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  Subjects -> ENVIRONMENTAL STUDIES (Total: 825 journals)
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Journal Cover Toxicology and Applied Pharmacology
  [SJR: 1.429]   [H-I: 117]   [16 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0041-008X - ISSN (Online) 1096-0333
   Published by Elsevier Homepage  [2970 journals]
  • Resveratrol protects the ovary against chromium-toxicity by enhancing
           endogenous antioxidant enzymes and inhibiting metabolic clearance of
           estradiol
    • Abstract: Publication date: 15 July 2016
      Source:Toxicology and Applied Pharmacology, Volume 303
      Author(s): Sakhila K. Banu, Jone A. Stanley, Kirthiram K. Sivakumar, Joe A. Arosh, Robert C. Burghardt
      Resveratrol (RVT), a polyphenolic component in grapes and red wine, has been known for its cytoprotective actions against several diseases. However, beneficial effects of RVT against early exposure to endocrine disrupting chemicals (EDCs) have not been understood. EDCs are linked to several ovarian diseases such as premature ovarian failure, polycystic ovary syndrome, early menopause and infertility in women. Hexavalent chromium (CrVI) is a heavy metal EDC, and widely used in >50 industries. Environmental contamination with CrVI in the US is rapidly increasing, predisposing the human to several illnesses including cancers and still birth. Our lab has been involved in determining the molecular mechanism of CrVI-induced female infertility and intervention strategies to mitigate CrVI effects. Lactating mother rats were exposed to CrVI (50ppm potassium dichromate) from postpartum days 1–21 through drinking water with or without RVT (10mg/kg body wt., through oral gavage daily). During this time, F1 females received respective treatments through mother's milk. On postnatal day (PND) 25, blood and the ovary, kidney and liver were collected from the F1 females for analyses. CrVI increased atresia of follicles by increasing cytochrome C and cleaved caspase-3; decreasing antiapoptotic proteins; decreasing estradiol (E2) biosynthesis and enhancing metabolic clearance of E2, increasing oxidative stress and decreasing endogenous antioxidants. RVT mitigated the effects of CrVI by upregulating cell survival proteins and AOXs; and restored E2 levels by inhibiting hydroxylation, glucuronidation and sulphation of E2. This is the first study to report the protective effects of RVT against any toxicant in the ovary.


      PubDate: 2016-05-21T00:25:53Z
       
  • Epigenetic silencing of miR-218 by the lncRNA CCAT1, acting via BMI1,
           promotes an altered cell cycle transition in the malignant transformation
           of HBE cells induced by cigarette smoke extract
    • Abstract: Publication date: Available online 19 May 2016
      Source:Toxicology and Applied Pharmacology
      Author(s): Lu Lu, Hui Xu, Fei Luo, Xinlu Liu, Xiaolin Lu, Qianlei Yang, Junchao Xue, Chao Chen, Le Shi, Qizhan Liu
      Cigarette smoking is the strongest risk factor for the development of lung cancer, the leading cause of cancer-related deaths. However, the molecular mechanisms leading to lung cancer are largely unknown. A long-noncoding RNA (lncRNA), CCAT1, regarded as cancer-associated, has been investigated extensively. Moreover, the molecular mechanisms of lncRNAs in regulation of microRNAs (miRNAs) induced by cigarette smoke remain unclear. In the present investigation, cigarette smoke extract (CSE) caused an altered cell cycle and increased CCAT1 levels and decreased miR-218 levels in human bronchial epithelial (HBE) cells. Depletion of CCAT1 attenuated the CSE-induced decreases of miR-218 levels, suggesting that miR-218 is negatively regulated by CCAT1 in HBE cells exposed to CSE. The CSE-induced increases of BMI1 levels and blocked by CCAT1 siRNA were attenuated by an miR-218 inhibitor. Moreover, in CSE-transformed HBE cells, the CSE-induced cell cycle changes and elevated neoplastic capacity were reversed by CCAT1 siRNA or BMI1 siRNA. This epigenetic silencing of miR-218 by CCAT1 induces an altered cell cycle transition through BMI1 and provides a new mechanism for CSE-induced lung carcinogenesis.


      PubDate: 2016-05-21T00:25:53Z
       
  • Mustard Vesicant-induced Lung Injury: Advances in Therapy
    • Abstract: Publication date: Available online 19 May 2016
      Source:Toxicology and Applied Pharmacology
      Author(s): Barry Weinberger, Rama Malaviya, Vasanthi Sunil, Alessandro Venosa, Diane E. Heck, Jeffrey D. Laskin, Debra L. Laskin
      Most mortality and morbidity following exposure to vesicants such as sulfur mustard is due to pulmonary toxicity. Acute injury is characterized by epithelial detachment and necrosis in the pharynx, trachea and bronchioles, while long-term consequences include fibrosis and in some instances, cancer. Current therapies to treat mustard poisoning are primarily palliative and do not target underlying pathophysiologic mechanisms. New knowledge about vesicant-induced pulmonary disease pathogenesis has led to the identification of potentially efficacious strategies to reduce injury by targeting inflammatory cells and mediators including reactive oxygen and nitrogen species, proteases and proinflammatory/cytotoxic cytokines. Therapeutics under investigation include corticosteroids, N-acetyl cysteine, which has both mucolytic and antioxidant properties, inducible nitric oxide synthase inhibitors, liposomes containing superoxide dismutase, catalase, and/or tocopherols, protease inhibitors, and cytokine antagonists such as anti-tumor necrosis factor (TNF)-α antibody and pentoxifylline. Antifibrotic and fibrinolytic treatments may also prove beneficial in ameliorating airway obstruction and lung remodeling. More speculative approaches include inhibitors of transient receptor potential channels, which regulate pulmonary epithelial cell membrane permeability, non-coding RNAs and mesenchymal stem cells. As mustards represent high priority chemical threat agents, identification of effective therapeutics for mitigating toxicity is highly significant.


      PubDate: 2016-05-21T00:25:53Z
       
  • Sinomenine attenuates renal fibrosis through Nrf2-mediated inhibition of
           oxidative stress and TGFβ signaling
    • Abstract: Publication date: Available online 17 May 2016
      Source:Toxicology and Applied Pharmacology
      Author(s): Tian Qin, Shasha Yin, Jun Yang, Qin Zhang, Yangyang Liu, Fengjie Huang, Wangsen Cao
      Renal fibrosis is the common feature of chronic kidney disease and mainly mediated by TGFβ-associated pro-fibrogenic signaling, which causes excessive extracellular matrix accumulation and successive loss of kidney functions. Sinomenine (SIN), an alkaloid derived from medicinal herb extensively used in treatment of rheumatoid arthritis and various inflammatory disorders, displays renal protective properties in experimental animals; however its pharmacological potency against renal fibrosis is not explored. In this study we report that SIN possesses strong anti-renal fibrosis functions in kidney cell and in mouse fibrotic kidney. SIN beneficially modulated the pro-fibrogenic protein expression in TGFβ-treated kidney cells and attenuated the renal fibrotic pathogenesis incurred by unilateral ureteral obstruction (UUO), which correlated with its activation of Nrf2 signaling - the key defender against oxidative stress with anti-fibrotic potentials. Further investigation on its regulation of Nrf2 downstream events revealed that SIN significantly balanced oxidative stress via improving the expression and activity of anti-oxidant and detoxifying enzymes, and interrupted the pro-fibrogenic signaling of TGFβ/Smad and Wnt/β-catenin. Even more impressively SIN achieved its anti-fibrotic activities in an Nrf2-dependent manner, suggesting that SIN regulation of Nrf2-associated anti-fibrotic activities constitutes a critical component of SIN's renoprotective functions. Collectively our studies have demonstrated a novel anti-fibrotic property of SIN and its upstream events and provided a molecular basis for SIN's potential applications in treatment of renal fibrosis-associated kidney disorders.
      Graphical abstract image

      PubDate: 2016-05-21T00:25:53Z
       
  • Development of HSPA1A promoter-driven luciferase reporter gene assays in
           human cells for assessing the oxidative damage induced by silver
           nanoparticles
    • Abstract: Publication date: Available online 17 May 2016
      Source:Toxicology and Applied Pharmacology
      Author(s): Lili Xin, Jianshu Wang, Leshuai W. Zhang, Bizhong Che, Guangzhu Dong, Guoqiang Fan, Kaiming Cheng
      The exponential increase in the total number of engineered nanoparticles in consumer products requires novel tools for rapid and cost-effective toxicology screening. In order to assess the oxidative damage induced by nanoparticles, toxicity test systems based on a human HSPA1A promoter-driven luciferase reporter in HepG2, LO2, A549, and HBE cells were established. After treated with heat shock and a group of silver nanoparticles (AgNPs) with different primary particle sizes, the cell viability, oxidative damage, and luciferase activity were determined. The time-dependent Ag+ ions release from AgNPs in cell medium was also evaluated. Our results showed that heat shock produced a strong time-dependent induction of relative luciferase activity in the four luciferase reporter cells. Surprisingly, at 4h of recovery, the relative luciferase activity was >98× the control level in HepG2-luciferase cells. Exposure to different sizes of AgNPs resulted in activation of the HSPA1A promoter in a dose-dependent manner, even at low cytotoxic or non-cytotoxic doses. The smaller (5nm) AgNPs were more potent in luciferase induction than the larger (50 and 75nm) AgNPs. These results were generally in accordance with the oxidative damage indicated by malondialdehyde concentration, reactive oxygen species induction and glutathione depletion, and Ag+ ions release in cell medium. Compared with the other three luciferase reporter cells, the luciferase signal in HepG2-luciferase cells is obviously more sensitive and stable. We conclude that the luciferase reporter cells, especially the HepG2-luciferase cells, could provide a valuable tool for rapid screening of the oxidative damage induced by AgNPs.


      PubDate: 2016-05-21T00:25:53Z
       
  • Modulation of expression and activity of intestinal multidrug
           resistance-associated protein 2 by xenobiotics
    • Abstract: Publication date: 15 July 2016
      Source:Toxicology and Applied Pharmacology, Volume 303
      Author(s): Guillermo Nicolás Tocchetti, Juan Pablo Rigalli, Maite Rocío Arana, Silvina Stella Maris Villanueva, Aldo Domingo Mottino
      The multidrug resistance-associated protein 2 (MRP2/ABCC2) is a transporter that belongs to the ATP-binding cassette (ABC) superfamily. In the intestine, it is localized to the apical membrane of the enterocyte and plays a key role in limiting the absorption of xenobiotics incorporated orally. MRP2 may also play a role in systemic clearance of xenobiotics available from the serosal side of the intestine. MRP2 transports a wide range of substrates, mainly organic anions conjugated with glucuronic acid, glutathione and sulfate and its expression can be modulated by xenobiotics at transcriptional- and post-transcriptional levels. Transcriptional regulation is usually mediated by a group of nuclear receptors. The pregnane X receptor (PXR) is a major member of this group. Relevant drugs described to up-regulate intestinal MRP2 via PXR are rifampicin, spironolactone and carbamazepine, among others. The constitutive androstane receptor (CAR, NR1I3) was also reported to modulate MRP2 expression, phenobarbital being a typical activator. Dietary compounds, including micronutrients and other natural products, are also capable of regulating intestinal MRP2 expression transcriptionally. We have given them particular attention since the composition of the food ingested daily is not necessarily supervised and may result in interactions with therapeutic drugs. Post-transcriptional regulation of MRP2 activity by xenobiotics, e.g. as a consequence of inhibitory actions, is also described in this review. Unfortunately, only few studies report on drug-drug or nutrient-drug interactions as a consequence of modulation of intestinal MRP2 activity by xenobiotics. Future clinical studies are expected to identify additional interactions resulting in changes in efficacy or safety of therapeutic drugs.
      Graphical abstract image

      PubDate: 2016-05-21T00:25:53Z
       
  • Curcumin rescues high fat diet-induced obesity and insulin sensitivity in
           mice through regulating SREBP pathway
    • Abstract: Publication date: Available online 18 May 2016
      Source:Toxicology and Applied Pharmacology
      Author(s): Lili Ding, Jinmei Li, Baoliang Song, Xu Xiao, Binfeng Zhang, Meng Qi, Wendong Huang, Li Yang, Zhengtao Wang
      Obesity and its major co-morbidity, type 2 diabetes, have reached an alarming epidemic prevalence without an effective treatment available. It has been demonstrated that inhibition of SREBP pathway may be a useful strategy to treat obesity with type 2 diabetes. Sterol regulatory element-binding proteins (SREBPs) are major transcription factors regulating the expression of genes involved in biosynthesis of cholesterol, fatty acid and triglyceride. In current study, we identified a small molecule, curcumin, inhibited the SREBP expression in vitro. The inhibition of SREBP by curcumin decreased the biosynthesis of cholesterol and fatty acid. In vivo, curcumin ameliorated HFD-induced body weight gain and fat accumulation in liver or adipose tissues, and improved serum lipid levels and insulin sensitivity in HFD-induced obese mice. Consistently, curcumin regulates SREBPs target genes and metabolism associated genes in liver or adipose tissues, which may directly contribute to the lower lipid level and improvement of insulin resistance. Take together, curcumin, a major active component of Curcuma longa could be a potential leading compound for development of drugs for the prevention of obesity and insulin resistance.


      PubDate: 2016-05-21T00:25:53Z
       
  • The effects of MEK1/2 inhibition on cigarette smoke exposure-induced ET
           receptor upregulation in rat cerebral arteries
    • Abstract: Publication date: Available online 19 May 2016
      Source:Toxicology and Applied Pharmacology
      Author(s): Lei Cao, Na-Na Ping, Yong-Xiao Cao, Wei Li, Yan Cai, Karin Warfvinge, Lars Edvinsson
      Cigarette smoking, a major stroke risk factor, upregulates endothelin receptors in cerebral arteries. The present study examined the effects of MEK1/2 pathway inhibition on cigarette smoke exposure-induced ET receptor upregulation. Rats were exposed to the secondhand smoke (SHS) for 8weeks followed by intraperitoneal injection of MEK1/2 inhibitor, U0126 for another 4weeks. The urine cotinine levels were assessed with high-performance liquid chromatography. Contractile responses of isolated cerebral arteries were recorded by a sensitive wire myograph. The mRNA and. Protein expression levels of receptor and MEK/ERK1/2 pathway molecules were examined by real-time PCR and Western blotting, respectively. Cerebral artery receptor localization was determined with immunohistochemistry. The results showed the urine cotinine levels from SHS exposure group were significantly higher than those from the fresh group. In addition, the MEK1/2 inhibitor, U0126 significantly reduced SHS exposure-increased ETA receptor mRNA and protein levels as well as contractile responses mediated by ETA receptors. The immunoreactivity of increased ETA receptor expression was primarily cytoplasmic in smooth muscle cells. In contrast, ETB receptor was noted in endothelial cells. However, the SHS-induced decrease in endothelium-dependent relaxation was unchanged after treatment. Furthermore, SHS increased the phosphorylation of MEK1/2 and ERK1/2 protein in cerebral arteries. By using U0126 could inhibit the phosphorylated ERK1/2 protein but not MEK1/2. Taken together, our data show that treatment with MEK1/2 pathway inhibitor offsets SHS exposure-induced ETA receptor upregulation in rat cerebral arteries.


      PubDate: 2016-05-21T00:25:53Z
       
  • Mustard vesicants alter expression of the endocannabinoid system in mouse
           skin
    • Abstract: Publication date: 15 July 2016
      Source:Toxicology and Applied Pharmacology, Volume 303
      Author(s): Irene M. Wohlman, Gabriella M. Composto, Diane E. Heck, Ned D. Heindel, C. Jeffrey Lacey, Christophe D. Guillon, Robert P. Casillas, Claire R. Croutch, Donald R. Gerecke, Debra L. Laskin, Laurie B. Joseph, Jeffrey D. Laskin
      Vesicants including sulfur mustard (SM) and nitrogen mustard (NM) are bifunctional alkylating agents that cause skin inflammation, edema and blistering. This is associated with alterations in keratinocyte growth and differentiation. Endogenous cannabinoids, including N-arachidonoylethanolamine (anandamide, AEA) and 2-arachidonoyl glycerol (2-AG), are important in regulating inflammation, keratinocyte proliferation and wound healing. Their activity is mediated by binding to cannabinoid receptors 1 and 2 (CB1 and CB2), as well as peroxisome proliferator-activated receptor alpha (PPARα). Levels of endocannabinoids are regulated by fatty acid amide hydrolase (FAAH). We found that CB1, CB2, PPARα and FAAH were all constitutively expressed in mouse epidermis and dermal appendages. Topical administration of NM or SM, at concentrations that induce tissue injury, resulted in upregulation of FAAH, CB1, CB2 and PPARα, a response that persisted throughout the wound healing process. Inhibitors of FAAH including a novel class of vanillyl alcohol carbamates were found to be highly effective in suppressing vesicant-induced inflammation in mouse skin. Taken together, these data indicate that the endocannabinoid system is important in regulating skin homeostasis and that inhibitors of FAAH may be useful as medical countermeasures against vesicants.
      Graphical abstract image

      PubDate: 2016-05-21T00:25:53Z
       
  • Editorial Board
    • Abstract: Publication date: 1 July 2016
      Source:Toxicology and Applied Pharmacology, Volume 302




      PubDate: 2016-05-16T00:12:21Z
       
  • Cover 4--TOC
    • Abstract: Publication date: 1 July 2016
      Source:Toxicology and Applied Pharmacology, Volume 302




      PubDate: 2016-05-16T00:12:21Z
       
  • Obaculactone protects against bleomycin-induced pulmonary fibrosis in mice
    • Abstract: Publication date: 15 July 2016
      Source:Toxicology and Applied Pharmacology, Volume 303
      Author(s): Xingqi Wang, Zijun Ouyang, Qian You, Shuai He, Qianqian Meng, Chunhui Hu, Xudong Wu, Yan Shen, Yang Sun, Xuefeng Wu, Qiang Xu
      Idiopathic pulmonary fibrosis is a progressive, degenerative and almost irreversible disease. There is hardly an effective cure for lung damage due to pulmonary fibrosis. The purpose of this study was to evaluate the role of obaculactone in an already-assessed model of idiopathic pulmonary fibrosis induced by bleomycin administration. Mice were subjected to intratracheal instillation of bleomycin, and obaculactone was given orally after bleomycin instillation daily for 23days. Treatment with obaculactone ameliorated body weight loss, lung histopathology abnormalities and pulmonary collagen deposition, with a decrease of the inflammatory cell number and the cytokine level in bronchoalveolar lavage fluid. Moreover, obaculactone inhibited the expression of icam1, vcam1, inos and cox2, and attenuated oxidative stress in bleomycin-treated lungs. Importantly, the production of collagen I and α-SMA in lung tissues as well as the levels of TGF-β1, ALK5, p-Smad2 and p-Smad3 in lung homogenates was also reduced after obaculactone treatment. Finally, the TGF-β1-induced epithelial-mesenchymal transition via Smad-dependent and Smad-independent pathways was reversed by obaculactone. Collectively, these data suggest that obaculactone may be a promising drug candidate for the treatment of idiopathic pulmonary fibrosis.


      PubDate: 2016-05-16T00:12:21Z
       
  • Bronchopulmonary C-fibers' IL1RI contributes to the prolonged apneic
           response to intra-atrial injection of capsaicin by prenatal nicotinic
           exposure in rat pups
    • Abstract: Publication date: Available online 12 May 2016
      Source:Toxicology and Applied Pharmacology
      Author(s): Lei Zhao, Jianguo Zhuang, Fadi Xu
      Prenatal nicotinic exposure (PNE) as a SIDS model reportedly sensitizes bronchopulmonary C-fibers (PCFs), contributing to the prolonged PCF-mediated apnea in rat pups, but the relevant mechanisms are not fully understood. Pulmonary IL-1β upregulated by cigarette smoke is known to stimulate or sensitize PCFs acting via IL-1 type I receptor (IL1RI) and inhibit inspiration frequency. Because of its upregulation observed in SIDS victims, we hypothesized that PNE increased pulmonary IL-1β release and IL1RI expression in pulmonary C-neurons via action on α7 nicotinic acetylcholine receptors (α7nAChR) to induce the prolonged PCF-mediated apnea. IL-1β in BALF and IL1RI in the nodose/jugular (N/J) ganglion and vagal pulmonary C-neurons retrogradely-traced were compared between Ctrl (saline) and PNE pups and among the vehicle-treated Ctrl and PNE and methyllycaconitine (a selective α7nAChR antagonist)-treated PNE pups. The effect of IL-1RI blockade (IL-1Ra) on the PCF-mediated apnea was also compared between Ctrl and PNE pups. PNE significantly elevated IL-1β in BALF and upregulated IL1RI gene and protein expression in N/J ganglia and gene in vagal pulmonary C-neurons. All of these responses were eliminated by pretreatment with blockade of α7nAChR. In addition, the prolonged PCF-mediated apnea in PNE pups was significantly shortened by right atrial bolus injection of IL-1Ra. We conclude that PNE enhances pulmonary IL-1β release and PCF IL1RI expression acting via α7nAChR in contributing to sensitization of PCFs and prolongation of the PCF-mediated apneic response.


      PubDate: 2016-05-16T00:12:21Z
       
  • ABC transporters affect the elimination and toxicity of CdTe quantum dots
           in liver and kidney cells
    • Abstract: Publication date: 15 July 2016
      Source:Toxicology and Applied Pharmacology, Volume 303
      Author(s): Mingli Chen, Huancai Yin, Pengli Bai, Peng Miao, Xudong Deng, Yingxue Xu, Jun Hu, Jian Yin
      This paper aimed to investigate the role of adenosine triphosphate-binding cassette (ABC) transporters on the efflux and the toxicity of nanoparticles in liver and kidney cells. In this study, we synthesized CdTe quantum dots (QDs) that were monodispersed and emitted green fluorescence (maximum peak at 530nm). Such QDs tended to accumulate in human hepatocellular carcinoma cells (HepG2), human kidney cells 2 (HK-2), and Madin-Darby canine kidney (MDCK) cells, and cause significant toxicity in all the three cell lines. Using specific inhibitors and inducers of P-glycoprotein (Pgp) and multidrug resistance associated proteins (Mrps), the cellular accumulation and subsequent toxicity of QDs in HepG2 and HK-2 cells were significantly affected, while only slight changes appeared in MDCK cells, corresponding well with the functional expressions of ABC transporters in cells. Moreover, treatment of QDs caused concentration- and time- dependent induction of ABC transporters in HepG2 and HK-2 cells, but such phenomenon was barely found in MDCK cells. Furthermore, the effects of CdTe QDs on ABC transporters were found to be greater than those of CdCl2 at equivalent concentrations of cadmium, indicating that the effects of QDs should be a combination of free Cd2+ and specific properties of QDs. Overall, these results indicated a strong dependence between the functional expressions of ABC transporters and the efflux of QDs, which could be an important reason for the modulation of QDs toxicity by ABC transporters.


      PubDate: 2016-05-10T20:19:43Z
       
  • Evaluation of novel biomarkers of nephrotoxicity in Cynomolgus monkeys
           treated with gentamicin
    • Abstract: Publication date: 15 July 2016
      Source:Toxicology and Applied Pharmacology, Volume 303
      Author(s): Jean-Charles Gautier, Xiaobing Zhou, Yi Yang, Thierry Gury, Zhe Qu, Xavier Palazzi, Jean-François Léonard, Mohamed Slaoui, Yaligara Veeranagouda, Isabelle Guizon, Eric Boitier, Aziz Filali-Ansary, Bart H.J. van den Berg, Oliver Poetz, Thomas Joos, Tianyi Zhang, Jufeng Wang, Philippe Detilleux, Bo Li
      Most studies to evaluate kidney safety biomarkers have been performed in rats. This study was conducted in Cynomolgus monkeys in order to evaluate the potential usefulness of novel biomarkers of nephrotoxicity in this species. Groups of 3 males were given daily intramuscular injections of gentamicin, a nephrotoxic agent known to produce lesions in proximal tubules, at dose-levels of 10, 25, or 50mg/kg/day for 10days. Blood and 16-h urine samples were collected on Days −7, −3, 2, 4, 7, and at the end of the dosing period. Several novel kidney safety biomarkers were evaluated, with single- and multiplex immunoassays and in immunoprecipitation-LC/MS assays, in parallel to histopathology and conventional clinical pathology parameters. Treatment with gentamicin induced a dose-dependent increase in kidney tubular cell degeneration/necrosis, ranging from minimal to mild severity at 10mg/kg/day, moderate at 25mg/kg/day, and to severe at 50mg/kg/day. The results showed that the novel urinary biomarkers, microalbumin, α1-microglobulin, clusterin, and osteopontin, together with the more traditional clinical pathology parameters, urinary total protein and N-acetyl-β-D-glucosaminidase (NAG), were more sensitive than blood urea nitrogen (BUN) and serum creatinine (sCr) to detect kidney injury in the monkeys given 10mg/kg/day gentamicin for 10days, a dose leading to an exposure which is slightly higher than the desired therapeutic exposure in clinics. Therefore, these urinary biomarkers represent non-invasive biomarkers of proximal tubule injury in Cynomolgus monkeys which may be potentially useful in humans.


      PubDate: 2016-05-06T22:03:23Z
       
  • Table of Contents
    • Abstract: Publication date: 15 June 2016
      Source:Toxicology and Applied Pharmacology, Volume 301




      PubDate: 2016-05-02T21:50:30Z
       
  • Alteration of canonical and non-canonical WNT-signaling by crystalline
           silica in human lung epithelial cells
    • Abstract: Publication date: 15 June 2016
      Source:Toxicology and Applied Pharmacology, Volume 301
      Author(s): Timothy N. Perkins, Mieke A. Dentener, Frank R. Stassen, Gernot G. Rohde, Brooke T. Mossman, Emiel F.M. Wouters, Niki L. Reynaert
      Growth and development of the mature lung is a complex process orchestrated by a number of intricate developmental signaling pathways. Wingless-type MMTV-integration site (WNT) signaling plays critical roles in controlling branching morphogenesis cell differentiation, and formation of the conducting and respiratory airways. In addition, WNT pathways are often re-activated in mature lungs during repair and regeneration. WNT- signaling has been elucidated as a crucial contributor to the development of idiopathic pulmonary fibrosis as well as other hyper-proliferative lung diseases. Silicosis, a detrimental occupational lung disease caused by excessive inhalation of crystalline silica dust, is hallmarked by repeated cycles of damaging inflammation, epithelial hyperplasia, and formation of dense, hyalinized nodules of whorled collagen. However, mechanisms of epithelial cell hyperplasia and matrix deposition are not well understood, as most research efforts have focused on the pronounced inflammatory response. Microarray data from our previous studies has revealed a number of WNT-signaling and WNT-target genes altered by crystalline silica in human lung epithelial cells. In the present study, we utilize pathway analysis to designate connections between genes altered by silica in WNT-signaling networks. Furthermore, we confirm microarray findings by QRT-PCR and demonstrate both activation of canonical (β-catenin) and down-regulation of non-canonical (WNT5A) signaling in immortalized (BEAS-2B) and primary (PBEC) human bronchial epithelial cells. These findings suggest that WNT-signaling and cross-talk with other pathways (e.g. Notch), may contribute to proliferative, fibrogenic and inflammatory responses to silica in lung epithelial cells.


      PubDate: 2016-05-02T21:50:30Z
       
  • Calcium channel blockers ameliorate iron overload-associated hepatic
           fibrosis by altering iron transport and stellate cell apoptosis
    • Abstract: Publication date: 15 June 2016
      Source:Toxicology and Applied Pharmacology, Volume 301
      Author(s): Ying Zhang, Xin Zhao, Yanzhong Chang, Yuanyuan Zhang, Xi Chu, Xuan Zhang, Zhenyi Liu, Hui Guo, Na Wang, Yonggang Gao, Jianping Zhang, Li Chu
      Liver fibrosis is the principal cause of morbidity and mortality in patients with iron overload. Calcium channel blockers (CCBs) can antagonize divalent cation entry into renal and myocardial cells and inhibit fibrogenic gene expression. We investigated the potential of CCBs to resolve iron overload-associated hepatic fibrosis. Kunming mice were assigned to nine groups (n =8 per group): control, iron overload, deferoxamine, high and low dose verapamil, high and low dose nimodipine, and high and low dose diltiazem. Iron deposition and hepatic fibrosis were measured in mouse livers. Expression levels of molecules associated with transmembrane iron transport were determined by molecular biology approaches. In vitro HSC-T6 cells were randomized into nine groups (the same groups as the mice). Changes in proliferation, apoptosis, and metalloproteinase expression in cells were detected to assess the anti-fibrotic effects of CCBs during iron overload conditions. We found that CCBs reduced hepatic iron content, intracellular iron deposition, the number of hepatic fibrotic areas, collagen expression levels, and hydroxyproline content. CCBs rescued abnormal expression of α1C protein in L-type voltage-dependent calcium channel (LVDCC) and down-regulated divalent metal transporter-1 (DMT-1) expression in mouse livers. In iron-overloaded HSC-T6 cells, CCBs reduced iron deposition, inhibited proliferation, induced apoptosis, and elevated expression of matrix metalloproteinase-13 (MMP-13) and tissue inhibitor of metalloproteinase-1 (TIMP-1). CCBs are potential therapeutic agents that can be used to address hepatic fibrosis during iron overload. They resolve hepatic fibrosis probably correlated with regulating transmembrane iron transport and inhibiting HSC growth.
      Graphical abstract image

      PubDate: 2016-05-02T21:50:30Z
       
  • Comparison of the inhibitory effects of tolcapone and entacapone against
           human UDP-glucuronosyltransferases
    • Abstract: Publication date: 15 June 2016
      Source:Toxicology and Applied Pharmacology, Volume 301
      Author(s): Xia Lv, Xin-Xin Wang, Jie Hou, Zhong-Ze Fang, Jing-Jing Wu, Yun-Feng Cao, Shu-Wen Liu, Guang-Bo Ge, Ling Yang
      Tolcapone and entacapone are two potent catechol-O-methyltransferase (COMT) inhibitors with a similar skeleton and displaying similar pharmacological activities. However, entacapone is a very safe drug used widely in the treatment of Parkinson's disease, while tolcapone is only in limited use for Parkinson's patients and needs careful monitoring of hepatic functions due to hepatotoxicity. This study aims to investigate and compare the inhibitory effects of entacapone and tolcapone on human UDP-glucosyltransferases (UGTs), as well as to evaluate the potential risks from the view of drug-drug interactions (DDI). The results demonstrated that both tolcapone and entacapone exhibited inhibitory effects on UGT1A1, UGT1A7, UGT1A9 and UGT1A10. In contrast to entacapone, tolcapone exhibited more potent inhibitory effects on UGT1A1, UGT1A7, and UGT1A10, while their inhibitory potentials against UGT1A9 were comparable. It is noteworthy that the inhibition constants (K i) of tolcapone and entacapone against bilirubin-O-glucuronidation in human liver microsomes (HLM) are determined as 0.68μM and 30.82μM, respectively, which means that the inhibition potency of tolcapone on UGT1A1 mediated bilirubin-O-glucuronidation in HLM is much higher than that of entacapone. Furthermore, the potential risks of tolcapone or entacapone via inhibition of human UGT1A1 were quantitatively predicted by the ratio of the areas under the plasma drug concentration-time curve (AUC). The results indicate that tolcapone may result in significant increase in AUC of bilirubin or the drugs primarily metabolized by UGT1A1, while entacapone is unlikely to cause a significant DDI through inhibition of UGT1A1.
      Graphical abstract image

      PubDate: 2016-05-02T21:50:30Z
       
  • Editorial Board
    • Abstract: Publication date: 15 June 2016
      Source:Toxicology and Applied Pharmacology, Volume 301




      PubDate: 2016-05-02T21:50:30Z
       
  • Specific histone modification responds to arsenic-induced oxidative stress
    • Abstract: Publication date: 1 July 2016
      Source:Toxicology and Applied Pharmacology, Volume 302
      Author(s): Lu Ma, Jun Li, Zhengbao Zhan, Liping Chen, Daochuan Li, Qing Bai, Chen Gao, Jie Li, Xiaowen Zeng, Zhini He, Shan Wang, Yongmei Xiao, Wen Chen, Aihua Zhang
      To explore whether specific histone modifications are associated with arsenic-induced oxidative damage, we recruited 138 arsenic-exposed and arsenicosis subjects from Jiaole Village, Xinren County of Guizhou province, China where the residents were exposed to arsenic from indoor coal burning. 77 villagers from Shang Batian Village that were not exposed to high arsenic coal served as the control group. The concentrations of urine and hair arsenic in the arsenic-exposure group were 2.4-fold and 2.1-fold (all P <0.001) higher, respectively, than those of the control group. Global histone modifications in human peripheral lymphocytes (PBLCs) were examined by ELISA. The results showed that altered global levels of H3K18ac, H3K9me2, and H3K36me3 correlated with both urinary and hair-arsenic levels of the subjects. Notably, H3K36me3 and H3K18ac modifications were associated with urinary 8-OHdG (H3K36me3: β=0.16; P =0.042, H3K18ac: β=−0.24; P =0.001). We also found that the modifications of H3K18ac and H3K36me3 were enriched in the promoters of oxidative stress response (OSR) genes in human embryonic kidney (HEK) cells and HaCaT cells, providing evidence that H3K18ac and H3K36me3 modifications mediate transcriptional regulation of OSR genes in response to NaAsO2 treatment. Particularly, we found that reduced H3K18ac modification correlated with suppressed expression of OSR genes in HEK cells with long term arsenic treatment and in PBLCs of all the subjects. Taken together, we reveal a critical role for specific histone modification in response to arsenic-induced oxidative damage.


      PubDate: 2016-05-02T21:50:30Z
       
  • Contents
    • Abstract: Publication date: 1 June 2016
      Source:Toxicology and Applied Pharmacology, Volume 300




      PubDate: 2016-04-27T21:29:31Z
       
  • A semisynthetic diterpenoid lactone inhibits NF-κB signalling to
           ameliorate inflammation and airway hyperresponsiveness in a mouse asthma
           model
    • Abstract: Publication date: 1 July 2016
      Source:Toxicology and Applied Pharmacology, Volume 302
      Author(s): J.C.-W. Lim, F.-Y. Goh, S.-R. Sagineedu, A.C.-H. Yong, S.M. Sidik, N.H. Lajis, W.S.F. Wong, J. Stanslas
      Andrographolide (AGP) and 14-deoxy-11,12-didehydroandrographolide (DDAG), two main diterpenoid constituents of Andrographis paniculata were previously shown to ameliorate asthmatic symptoms in a mouse model. However, due to inadequacies of both compounds in terms of drug-likeness, DDAG analogues were semisynthesised for assessment of their anti-asthma activity. A selected analogue, 3,19-diacetyl-14-deoxy-11,12-didehydroandrographolide (SRS27), was tested for inhibitory activity of NF-κB activation in TNF-α-induced A549 cells and was subsequently evaluated in a mouse model of ovalbumin (OVA)-induced asthma. Female BALB/c mice, 6–8weeks old were sensitized on days 0 and 14, and challenged on days 22, 23 and 24 with OVA. Compound or vehicle (3% dimethyl sulfoxide) was administered intraperitoneally 1h before and 11h after each OVA aerosol challenge. On day 25, pulmonary eosinophilia, airway hyperresponsiveness, mucus hypersecretion, inflammatory cytokines such as IL-4, -5 and -13 in BAL fluid, gene expression of inflammatory mediators such as 5-LOX, E-selectin, VCAM-1, CCL5, TNF-α, AMCase, Ym2, YKL-40, Muc5ac, CCL2 and iNOS in animal lung tissues, and serum IgE were determined. SRS27 at 30μM was found to suppress NF-κB nuclear translocation in A549 cells. In the ovalbumin-induced mouse asthma model, SRS27 at 3mg/kg displayed a substantial decrease in pulmonary eosinophilia, BAL fluid inflammatory cytokines level, serum IgE production, mucus hypersecretion and gene expression of inflammatory mediators in lung tissues. SRS27 is the first known DDAG analogue effective in ameliorating inflammation and airway hyperresponsiveness in the ovalbumin-induced mouse asthma model.
      Graphical abstract image

      PubDate: 2016-04-27T21:29:31Z
       
  • Deoxynivalenol exposure induces autophagy/apoptosis and epigenetic
           modification changes during porcine oocyte maturation
    • Abstract: Publication date: 1 June 2016
      Source:Toxicology and Applied Pharmacology, Volume 300
      Author(s): Jun Han, Qiao-Chu Wang, Cheng-Cheng Zhu, Jun Liu, Yu Zhang, Xiang-Shun Cui, Nam-Hyung Kim, Shao-Chen Sun
      Deoxynivalenol (DON) is a widespread trichothecene mycotoxin which contaminates agricultural staples and elicits a complex spectrum of toxic effects on humans and animals. It has been shown that DON impairs oocyte maturation, reproductive function and causes abnormal fetal development in mammals; however, the mechanisms remain unclear. In the present study, we investigate the possible reasons of the toxic effects of DON on porcine oocytes. Our results showed that DON significantly inhibited porcine oocyte maturation and disrupted meiotic spindle by reducing p-MAPK protein level, which caused retardation of cell cycle progression. In addition, up-regulated LC3 protein expression and aberrant Lamp2, LC3 and mTOR mRNA levels were observed with DON exposure, together with Annexin V-FITC staining assay analysis, these results indicated that DON treatment induced autophagy/apoptosis in porcine oocytes. We also showed that DON exposure increased DNA methylation level in porcine oocytes through altering DNMT3A mRNA levels. Histone methylation levels were also changed showing with increased H3K27me3 and H3K4me2 protein levels, and mRNA levels of their relative methyltransferase genes, indicating that epigenetic modifications were affected. Taken together, our results suggested that DON exposure reduced porcine oocytes maturation capability through affecting cytoskeletal dynamics, cell cycle, autophagy/apoptosis and epigenetic modifications.


      PubDate: 2016-04-27T21:29:31Z
       
  • Editorial Board
    • Abstract: Publication date: 1 June 2016
      Source:Toxicology and Applied Pharmacology, Volume 300




      PubDate: 2016-04-27T21:29:31Z
       
  • Beneficial effects of vitamin C treatment on pregnant rats exposed to
           formaldehyde: Reversal of immunosuppression in the offspring
    • Abstract: Publication date: 1 June 2016
      Source:Toxicology and Applied Pharmacology, Volume 300
      Author(s): Beatriz Silva Ibrahim, Éric Diego Barioni, Cíntia Heluany, Tárcio Teodoro Braga, Carine Cristiane Drewes, Silvia Goes Costa, Niels Olsen Saraiva Câmara, Sandra Helena Poliselli Farsky, Adriana Lino-dos-Santos-Franco
      Inhalation of formaldehyde (FA) during the pregnancy induces oxidative stress in the uterus, and here we hypothesized that this mechanism may be responsible for the impaired immune response detected in the offspring. In order to investigate the protective effects of Vitamin C on the oxidative stress induced by FA in the uterine microenvironment, pregnant Wistar rats were treated with vitamin C (150mg/kg, gavage) or vehicle (distilled water, gavage) 1h before FA exposure (0.92mg/m3, 1h/day, 5days/week), for 21days, and the 30days old offspring were submitted to LPS injection (Salmonella abortus equi, 5mg/kg, i.p.). The enhanced gene expression of iNOS, COX-1 and COX-2 and decreased gene expression of SOD-2 in the uterus of FA exposed mothers was rescued by Vit C treatment. Moreover, vitamin C rescued the impaired immune response elicited by LPS in the offspring from FA exposed mothers, by increasing the number of blood and bone marrow leukocytes, and augmenting gene expression of IL-6 and reducing mRNA levels of IL-10 and IFN in the lungs. Vitamin C treatment did not rescue the impaired TLR4-NF-kB pathway in the lung of the offspring, suggesting that FA-induced uterine oxidative stress affects other inflammatory pathways activated by LPS in the offspring. Together, data obtained here confirm our hypothesis that FA-induced oxidative stress in the uterine microenvironment modifies the programming mechanisms of the immune defenses of offspring, leading to an impaired host defense.


      PubDate: 2016-04-27T21:29:31Z
       
  • An extensive cocktail approach for rapid risk assessment of in vitro
           CYP450 direct reversible inhibition by xenobiotic exposure
    • Abstract: Publication date: Available online 20 April 2016
      Source:Toxicology and Applied Pharmacology
      Author(s): Dany Spaggiari, Youssef Daali, Serge Rudaz
      Acute exposure to environmental factors strongly affects the metabolic activity of P450. As a consequence, the risk of interaction could be increased, modifying the clinical outcomes of a medication. Because toxic agents cannot be administered to humans for ethical reasons, in vitro approaches are therefore essential to evaluate their impact on P450 activities. In this work, an extensive cocktail mixture was developed and validated for in vitro P450 inhibition studies using human liver microsomes (HLM). The cocktail comprised eleven P450-specific probe substrates to simultaneously assess the activities of the following isoforms: 1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, 2J2 and subfamily 3A. The high selectivity and sensitivity of the developed UHPLC-MS/MS method were critical for the success of this methodology, whose main advantages are: (i) the use of eleven probe substrates with minimized interactions, (ii) a low HLM concentration, (iii) fast incubation (5min) and (iv) the use of metabolic ratios as microsomal P450 activities markers. This cocktail approach was successfully validated by comparing the obtained IC50 values for model inhibitors with those generated with the conventional single probe methods. Accordingly, reliable inhibition values could be generated 10-fold faster using a 10-fold smaller amount of HLM compared to individual assays. This approach was applied to assess the P450 inhibition potential of widespread insecticides, namely, chlorpyrifos, fenitrothion, methylparathion and profenofos. In all cases, P450 2B6 was the most affected with IC50 values in the nanomolar range. For the first time, mixtures of these four insecticides incubated at low concentrations showed a cumulative inhibitory in vitro effect on P450 2B6.
      Graphical abstract image

      PubDate: 2016-04-23T21:01:14Z
       
  • Mitochondrial nucleoid clusters protect newly synthesized mtDNA during
           Doxorubicin- and Ethidium Bromide-induced mitochondrial stress
    • Abstract: Publication date: Available online 19 April 2016
      Source:Toxicology and Applied Pharmacology
      Author(s): Lukáš Alán, Tomáš Špaček, David Pajuelo Reguera, Martin Jabůrek, Petr Ježek
      Mitochondrial DNA (mtDNA) is compacted in ribonucleoprotein complexes called nucleoids, which can divide or move within the mitochondrial network. Mitochondrial nucleoids are able to aggregate into clusters upon reaction with intercalators such as the mtDNA depletion agent Ethidium Bromide (EB) or anticancer drug Doxorobicin (DXR). However, the exact mechanism of nucleoid clusters formation remains unknown. Resolving these processes may help to elucidate the mechanisms of DXR-induced cardiotoxicity. Therefore, we addressed the role of two key nucleoid proteins; mitochondrial transcription factor A (TFAM) and mitochondrial single-stranded binding protein (mtSSB); in the formation of mitochondrial nucleoid clusters during the action of intercalators. We found that both intercalators cause numerous aberrations due to perturbing their native status. By blocking mtDNA replication, both agents also prevented mtDNA association with TFAM, consequently causing nucleoid aggregation into large nucleoid clusters enriched with TFAM, co-existing with the normal nucleoid population. In the later stages of intercalation (>48h), TFAM levels were reduced to 25%. In contrast, mtSSB was released from mtDNA and freely distributed within the mitochondrial network. Nucleoid clusters mostly contained nucleoids with newly replicated mtDNA, however the nucleoid population which was not in replication mode remained outside the clusters. Moreover, the nucleoid clusters were enriched with p53, an anti-oncogenic gatekeeper. We suggest that mitochondrial nucleoid clustering is a mechanism for protecting nucleoids with newly replicated DNA against intercalators mediating genotoxic stress. These results provide new insight into the common mitochondrial response to mtDNA stress and can be implied also on DXR-induced mitochondrial cytotoxicity.


      PubDate: 2016-04-19T20:48:53Z
       
  • Assessment of mitochondrial dysfunction-related, drug-induced
           hepatotoxicity in primary rat hepatocytes
    • Abstract: Publication date: Available online 16 April 2016
      Source:Toxicology and Applied Pharmacology
      Author(s): Cong Liu, Shuichi Sekine, Kousei Ito
      Evidence that mitochondrial dysfunction plays a central role in drug-induced liver injury is rapidly accumulating. In contrast to physiological conditions, in which almost all adenosine triphosphate (ATP) in hepatocytes is generated in mitochondria via aerobic respiration, the high glucose content and limited oxygen supply of conventional culture systems force primary hepatocytes to generate most ATP via cytosolic glycolysis. Thus, such anaerobically poised cells are resistant to xenobiotics that impair mitochondrial function, and are not suitable to identify drugs with mitochondrial liabilities. In this study, primary rat hepatocytes were cultured in galactose-based medium, instead of the conventional glucose-based medium, and in hyperoxia to improve the reliance of energy generation on aerobic respiration. Activation of mitochondria was verified by diminished cellular lactate release and increased oxygen consumption. These conditions improved sensitivity to the mitochondrial complex I inhibitor rotenone. Since oxidative stress is also a general cause of mitochondrial impairment, cells were exposed to test compounds in the presence of transferrin to increase the generation of reactive oxygen species via increased uptake of iron. Finally, 14 compounds with reported mitochondrial liabilities were tested to validate this new drug-induced mitochondrial toxicity assay. Overall, the culture of primary rat hepatocytes in galactose, hyperoxia and transferrin is a useful model for the identification of mitochondrial dysfunction-related drug-induced hepatotoxicity.


      PubDate: 2016-04-19T20:48:53Z
       
  • Advantageous use of HepaRG cells for the screening and mechanistic study
           of drug-induced steatosis
    • Abstract: Publication date: Available online 16 April 2016
      Source:Toxicology and Applied Pharmacology
      Author(s): Laia Tolosa, M. José Gómez-Lechón, Nuria Jiménez, David Hervás, Ramiro Jover, M. Teresa Donato
      Only a few in vitro assays have been proposed to evaluate the steatotic potential of new drugs. The present study examines the utility of HepaRG cells as a cell-based assay system for screening drug-induced liver steatosis. A high-content screening assay was run to evaluate multiple toxicity-related cell parameters in HepaRG cells exposed to 28 compounds, including drugs reported to cause steatosis through different mechanisms and non-steatotic compounds. Lipid content was the most sensitive parameter for all the steatotic drugs, whereas no effects on lipid levels were produced by non-steatotic compounds. Apart from fat accumulation, increased ROS production and altered mitochondrial membrane potential were also found in the cells exposed to steatotic drugs, which indicates that all these cellular events contributed to drug-induced hepatotoxicity. These findings are of clinical relevance as most effects were observed at drug concentrations under 100-fold of the therapeutic peak plasmatic concentration. HepaRG cells showed increased lipid overaccumulation vs. HepG2 cells, which suggests greater sensitivity to drug-induced steatosis. An altered expression profile of transcription factors and the genes that code key proteins in lipid metabolism was also found in the cells exposed to drugs capable of inducing liver steatosis. Our results generally indicate the value of HepaRG cells for assessing the risk of liver damage associated with steatogenic compounds and for investigating the molecular mechanisms involved in drug-induced steatosis.
      Graphical abstract image

      PubDate: 2016-04-19T20:48:53Z
       
  • Nonselective inhibition of the epigenetic transcriptional regulator BET
           induces marked lymphoid and hematopoietic toxicity in mice
    • Abstract: Publication date: 1 June 2016
      Source:Toxicology and Applied Pharmacology, Volume 300
      Author(s): Dong U. Lee, Paula Katavolos, Gopinath Palanisamy, Arna Katewa, Charly Sioson, Janice Corpuz, Jodie Pang, Kevin DeMent, Edna Choo, Nico Ghilardi, Dolores Diaz, Dimitry M. Danilenko
      Bromo and extra terminal (BET) proteins (BRD2, BRD3, BRD4 and BRDT) are epigenetic transcriptional regulators required for efficient expression of growth promoting, cell cycle progression and antiapoptotic genes. Through their bromodomain, these proteins bind to acetylated lysine residues of histones and are recruited to transcriptionally active chromatin. Inhibition of the BET-histone interaction provides a tractable therapeutic strategy to treat diseases that may have epigenetic dysregulation. JQ1 is a small molecule that blocks BET interaction with histones. It has been shown to decrease proliferation of patient-derived multiple myeloma in vitro and to decrease tumor burden in vivo in xenograft mouse models. While targeting BET appears to be a viable and efficacious approach, the nonclinical safety profile of BET inhibition remains to be well-defined. We report that mice dosed with JQ1 at efficacious exposures demonstrate dose-dependent decreases in their lymphoid and immune cell compartments. At higher doses, JQ1 was not tolerated and due to induction of significant body weight loss led to early euthanasia. Flow cytometry analysis of lymphoid tissues showed a decrease in both B- and T-lymphocytes with a concomitant decrease in peripheral white blood cells that was confirmed by hematology. Further investigation with the inactive enantiomer of JQ1 showed that these in vivo effects were on-target mediated and not elicited through secondary pharmacology due to chemical structure.


      PubDate: 2016-04-16T03:09:43Z
       
  • 4-(E)-{(p-tolylimino)-methylbenzene-1,2-diol}, 1 a novel resveratrol
           analog, differentially regulates estrogen receptors α and β in
           breast cancer cells
    • Abstract: Publication date: 15 June 2016
      Source:Toxicology and Applied Pharmacology, Volume 301
      Author(s): Amruta Ronghe, Anwesha Chatterjee, Bhupendra Singh, Prasad Dandawate, Fatma Abdalla, Nimee K. Bhat, Subhash Padhye, Hari K. Bhat
      Breast cancer is a public health concern worldwide. Prolonged exposure to estrogens has been implicated in the development of breast neoplasms. Epidemiologic and experimental evidence suggest a chemopreventive role of phytoestrogens in breast cancers. Resveratrol, a naturally occurring phytoestrogen, has been shown to have potent anti-cancer properties. However, poor efficacy and bioavailability have prevented the use of resveratrol in clinics. In order to address these problems, we have synthesized a combinatorial library of azaresveratrol analogs and tested them for their ability to inhibit the proliferation of breast cancer cells. We have recently shown that 4-(E)-{(p-tolylimino)-methylbenzene-1,2-diol} (TIMBD), has better anti-cancer properties than resveratrol and any other resveratrol analog we have synthesized so far. The objective of this study was to investigate the regulation of estrogen receptors (ERs) α and β by TIMBD in breast cancer cell lines. We demonstrate that TIMBD significantly induces the mRNA and protein expression levels of ERβ and inhibits that of ERα. TIMBD inhibits mRNA and protein expression levels of oncogene c-Myc, and cell cycle protein cyclin D1, which are important regulators of cellular proliferation. TIMBD significantly induces protein expression levels of tumor suppressor genes p53 and p21 in MCF-7 cells. TIMBD inhibits c-Myc in an ERβ-dependent fashion in MCF-10A and ERβ1-transfected MDA-MB-231 cells, suggesting regulation of ERs as an important upstream mechanism of this analog. ERβ plays a partial role in inhibition of proliferation by TIMBD while ERα overexpression does not significantly affect TIMBD's inhibition.


      PubDate: 2016-04-16T03:09:43Z
       
  • Serca2a and Na+/Ca2+ exchanger are involved in left ventricular function
           following cardiac remodelling of female rats treated with anabolic
           androgenic steroid
    • Abstract: Publication date: Available online 10 April 2016
      Source:Toxicology and Applied Pharmacology
      Author(s): Andrews Marques do Nascimento, Ewelyne Miranda de Lima, Girlandia Alexandre Brasil, Izabela Facco Caliman, Josiane Fernandes da Silva, Virgínia Soares Lemos, Tadeu Uggere de Andrade, Nazaré Souza Bissoli
      Anabolic-androgenic steroids are misused, including by women, but little is known about the cardiovascular effects of these drugs on women. Aim: To evaluated the effects of nandrolone decanoate (ND) and resistive physical exercise on cardiac contractility in young female rats. Main methods: Female Wistar rats were separated into 4 groups: C (untrained animals); E (animals were submitted to resistance exercise by jumping in water 5 times per week); ND (animals were treated with ND, 20mg/kg/week for 4weeks); and NDE (trained and treated). The haemodynamic parameters (+dP/dtmax, −dP/dtmin and Tau) were assessed in the left ventricle. The heart was collected for histological analyses and collagen deposition. The gastrocnemius muscle was weighed, and hypertrophy was assessed by the ratio of their weights to gastrocnemius/tibia length. The expression of calcium handling proteins was measured by western blot analysis. Results: ND treatment and physical exercise increased cardiac contractility and relaxation. In addition, ND promoted increases in phospholamban phosphorylated (p-PLB) and isoforms of sarcoplasmic/endoplasmic reticulum calcium ATPase 2 (SERCA2a) expression, while resistance exercise increased the phosphorylation of PLB and expression of Na+/Ca2+ exchangers (NCX). Cardiac hypertrophy and collagen deposition were observed after ND treatment. Conclusion: Regulatory components of cytosolic calcium, such as SERCA2a and p-PLB, play important roles in modulating the contractility and relaxation effects of ND in females.
      Graphical abstract image

      PubDate: 2016-04-16T03:09:43Z
       
  • Crosstalk between liver antioxidant and the endocannabinoid systems after
           chronic administration of the FAAH inhibitor, URB597, to hypertensive rats
           
    • Abstract: Publication date: Available online 13 April 2016
      Source:Toxicology and Applied Pharmacology
      Author(s): Michał Biernacki, Wojciech Łuczaj, Agnieszka Gęgotek, Marek Toczek, Katarzyna Bielawska, Elżbieta Skrzydlewska
      Hypertension is accompanied by perturbations to the endocannabinoid and antioxidant systems. Thus, potential pharmacological treatments for hypertension should be examined as modulators of these two metabolic systems. The aim of this study was to evaluate the effects of chronic administration of the fatty acid amide hydrolase (FAAH) inhibitor [3-(3-carbamoylphenyl)phenyl]N-cyclohexylcarbamate (URB597) on the endocannabinoid system and on the redox balance in the livers of DOCA-salt hypertensive rats. Hypertension caused an increase in the levels of endocannabinoids [anandamide (AEA), 2-arachidonoyl-glycerol (2-AG) and N-arachidonoyl-dopamine (NADA)] and CB1 receptor and the activities of FAAH and monoacylglycerol lipase (MAGL). These effects were accompanied by an increase in the level of reactive oxygen species (ROS), a decrease in antioxidant activity/level, enhanced expression of transcription factor Nrf2 and changes to Nrf2 activators and inhibitors. Moreover, significant increases in lipid, DNA and protein oxidative modifications, which led to enhanced levels of proapoptotic caspases, were also observed. URB597 administration to the hypertensive rats resulted in additional increases in the levels of AEA, NADA and the CB1 receptor, as well as decreases in vitamin E and C levels, glutathione peroxidase and glutathione reductase activities and Nrf2 expression. Thus, after URB597 administration, oxidative modifications of cellular components were increased, while the inflammatory response was reduced. This study revealed that chronic treatment of hypertensive rats with URB597 disrupts the endocannabinoid system, which causes an imbalance in redox status. This imbalance increases the levels of electrophilic lipid peroxidation products, which later participate in metabolic disturbances in liver homeostasis.


      PubDate: 2016-04-16T03:09:43Z
       
  • Effects of developmental exposure to perfluorooctanoic acid (PFOA) on long
           bone morphology and bone cell differentiation
    • Abstract: Publication date: Available online 9 April 2016
      Source:Toxicology and Applied Pharmacology
      Author(s): A. Koskela, M.A. Finnilä, M. Korkalainen, S. Spulber, J. Koponen, H. Håkansson, J. Tuukkanen, M. Viluksela
      Perfluorooctanoic acid (PFOA) is a ubiquitous and persistent environmental chemical, which has been used extensively due to its stability and surface tension-lowering properties. Toxicological effects include induction of neonatal mortality and reproductive toxicity. In this study, pregnant C57BL/6 mice were exposed orally to 0.3mg PFOA/kg/day throughout pregnancy, and female offspring were studied at the age of 13 or 17months. Morphometrical and biomechanical properties of femurs and tibias were analyzed with micro-computed tomography and 3-point bending, and bone PFOA concentrations were determined by mass spectrometry. The effects of PFOA on bone cell differentiation were studied in osteoclasts from C57BL/6 mice and in the MC3T3 pre-osteoblast cell line. PFOA exposed mice showed increased femoral periosteal area as well as decreased mineral density of tibias. Biomechanical properties of these bones were not affected. Bone PFOA concentrations were clearly elevated even at the age of 17months. In osteoblasts, low concentrations of PFOA increased osteocalcin (OCN) expression and calcium secretion, but at PFOA concentrations of 100μM and above osteocalcin (OCN) expression and calcium secretion were decreased. The number of osteoclasts was increased at all PFOA concentrations tested and resorption activity dose-dependently increased from 0.1–1.0μM, but decreased at higher concentrations. The results show that PFOA accumulates in bone and is present in bones until the old age. PFOA has the potential to influence bone turnover over a long period of time. Therefore bone is a target tissue for PFOA, and altered bone geometry and mineral density seem to persist throughout the life of the animal.


      PubDate: 2016-04-09T08:57:33Z
       
  • Nodularin induces tumor necrosis factor-alpha and mitogen-activated
           protein kinases (MAPK) and leads to induction of endoplasmic reticulum
           stress
    • Abstract: Publication date: 1 June 2016
      Source:Toxicology and Applied Pharmacology, Volume 300
      Author(s): Nicole Meili, Verena Christen, Karl Fent
      Nodularin is produced by the cyanobacterium Nodularia spumigena. It is of concern due to hepatotoxicity in humans and animals. Here we investigated unexplored molecular mechanisms by transcription analysis in human liver cells, focusing on induction of pro-inflammatory cytokines, the tumor necrosis factor α (TNF-α), endoplasmic reticulum (ER) stress and components of the activator protein-1 complex in human hepatoma cells (Huh7) exposed to non-cytotoxic (0.1 and 1μM) and toxic concentrations (5μM) for 24, 48, and 72h. Transcripts of TNF-α and ER stress marker genes were strongly induced at 1 and 5μM at all time-points. TNF-α led to induction of mitogen-activated protein kinases (MAPK), as demonstrated by induction of CJUN and CFOS, which form the AP-1 complex. Human primary liver cells reacted more sensitive than Huh7 cells. They showed higher cytotoxicity and induction of TNF-α and ER stress at 2.5nM, while HepG2 cells were insensitive up to 10μM due to low expression of organic anion transporting polypeptides. Furthermore, nodularin led to induction of TNF-α protein, and CCAAT/enhancer-binding protein-homologous (CHOP) protein. Our data indicate that nodularin induces inflammation and ER stress and leads to activation of MAPK in liver cells. All of these activated pathways, which were analysed here for the first time in detail, may contribute to the hepatotoxic, and tumorigenic action of nodularin.
      Graphical abstract image

      PubDate: 2016-04-08T08:55:33Z
       
  • Tea polyphenols EGCG and TF restrict tongue and liver carcinogenesis
           simultaneously induced by N-nitrosodiethylamine in mice
    • Abstract: Publication date: Available online 4 April 2016
      Source:Toxicology and Applied Pharmacology
      Author(s): Subhayan Sur, Debolina Pal, Rituparna Roy, Atish Barua, Anup Roy, Prosenjit Saha, Chinmay Kumar Panda
      The aim of this study is to understand the molecular mechanisms of N-nitrosodiethylamine (NDEA) induced multi-organ carcinogenesis in tongue and liver of the same mouse and restriction of carcinogenesis by Epigallocatechin gallate (EGCG) and Theaflavin (TF), if any. For that purpose, cellular proliferation/apoptosis, prevalence of CD44 positive stem cell population and expressions of some key regulatory genes of self renewal Wnt and Hedgehog (Hh) pathways and some of their associated genes were analyzed in the NDEA induced tongue and liver lesions in absence or presence of EGCG/TF. Chronic NDEA exposure in oral cavity could decrease mice body weights and induce tongue and liver carcinogenesis with similar histological stages (severe dysplasia up to 30thweeks of NDEA administration). Increasing mice body weights were seen in continuous and post EGCG/TF treated groups. EGCG/TF treatment could restrict both the carcinogenesis at similar histological stages showing potential chemopreventive effect in continuous treated groups (mild dysplasia) followed by pre treatment (moderate dysplasia) and therapeutic efficacy in post treated groups (mild dysplasia) up to 30thweek. The mechanism of carcinogenesis by NDEA and restriction by the EGCG/TF in both tongue and liver were similar and found to be associated with modulation in cellular proliferation/apoptosis and prevalence of CD44 positive population. The up-regulation of self renewal Wnt/β-catenin, Hh/Gli1 pathways and their associated genes Cyclin D1, cMyc and EGFR along with down regulation of E-cadherin seen during the carcinogenesis processes were found to be modulated during the restriction processes by EGCG/TF.
      Graphical abstract image

      PubDate: 2016-04-04T13:14:44Z
       
  • 14-Deoxy-11,12-didehydroandrographolide induces DDIT3-dependent
           endoplasmic reticulum stress-mediated autophagy in T-47D breast carcinoma
           cells
    • Abstract: Publication date: Available online 2 April 2016
      Source:Toxicology and Applied Pharmacology
      Author(s): Heng Kean Tan, Tengku Sifzizul Tengku Muhammad, Tan Mei Lan
      14-Deoxy-11,12-didehydroandrographolide (14-DDA), a major diterpenoid isolated from Andrographis paniculata (Burm.f.) Nees, is known to be cytotoxic and elicits a non-apoptotic cell death in T-47D breast carcinoma cells. In this study, the mechanistic toxicology properties of 14-DDA in T-47D cells were further investigated. 14-DDA is found to induce the formation of endoplasmic reticulum (ER) vacuoles and autophagosomes, with concurrent upregulation of LC3-II in the breast carcinoma cells. It stimulated an increase in cytosolic calcium concentration and caused a collapse in mitochondrial membrane potential in these cells. In addition, both DDIT3 and GADD45A, molecules implicated in ER stress pathway, were significantly upregulated. DDIT3 knockdown suppressed the formation of both ER vacuoles and autophagosomes, indicating that 14-DDA-induced ER stress and autophagy is dependent on this transcription factor. Collectively, it is possible that GADD45A/p38 MAPK/DDIT3 pathway is involved in the 14-DDA-induced ER-stress-mediated autophagy in T-47D cells.


      PubDate: 2016-04-04T13:14:44Z
       
  • Pathophysiologic mechanisms of biomedical nanomaterials
    • Abstract: Publication date: 15 May 2016
      Source:Toxicology and Applied Pharmacology, Volume 299
      Author(s): Liming Wang, Chunying Chen
      Nanomaterials (NMs) have been widespread used in biomedical fields, daily consuming, and even food industry. It is crucial to understand the safety and biomedical efficacy of NMs. In this review, we summarized the recent progress about the physiological and pathological effects of NMs from several levels: protein-nano interface, NM-subcellular structures, and cell–cell interaction. We focused on the detailed information of nano-bio interaction, especially about protein adsorption, intracellular trafficking, biological barriers, and signaling pathways as well as the associated mechanism mediated by nanomaterials. We also introduced related analytical methods that are meaningful and helpful for biomedical effect studies in the future. We believe that knowledge about pathophysiologic effects of NMs is not only significant for rational design of medical NMs but also helps predict their safety and further improve their applications in the future.


      PubDate: 2016-03-26T12:39:43Z
       
  • A redox proteomics approach to investigate the mode of action of
           nanomaterials
    • Abstract: Publication date: 15 May 2016
      Source:Toxicology and Applied Pharmacology, Volume 299
      Author(s): Christian Riebeling, Martin Wiemann, Jürgen Schnekenburger, Thomas A.J. Kuhlbusch, Wendel Wohlleben, Andreas Luch, Andrea Haase
      Numbers of engineered nanomaterials (ENMs) are steadily increasing. Therefore, alternative testing approaches with reduced costs and high predictivity suitable for high throughput screening and prioritization are urgently needed to ensure a fast and effective development of safe products. In parallel, extensive research efforts are targeted to understanding modes of action of ENMs, which may also support the development of new predictive assays. Oxidative stress is a widely accepted paradigm associated with different adverse outcomes of ENMs. It has frequently been identified in in vitro and in vivo studies and different assays have been developed for this purpose. Fluorescent dye based read-outs are most frequently used for cell testing in vitro but may be limited due to possible interference of the ENMs. Recently, other assays have been put forward such as acellular determination of ROS production potential using methods like electron spin resonance, antioxidant quantification or the use of specific sensors. In addition, Omics based approaches have gained increasing attention. In particular, redox proteomics can combine the assessment of oxidative stress with the advantage of getting more detailed mechanistic information. Here we propose a comprehensive testing strategy for assessing the oxidative stress potential of ENMs, which combines acellular methods and fast in vitro screening approaches, as well as a more involved detailed redox proteomics approach. This allows for screening and prioritization in a first tier and, if required, also for unraveling mechanistic details down to compromised signaling pathways.


      PubDate: 2016-03-26T12:39:43Z
       
  • Integrative analysis of genes and miRNA alterations in human embryonic
           stem cells-derived neural cells after exposure to silver nanoparticles
    • Abstract: Publication date: 15 May 2016
      Source:Toxicology and Applied Pharmacology, Volume 299
      Author(s): Jung-Hwa Oh, Mi-Young Son, Mi-Sun Choi, Soojin Kim, A-young Choi, Hyang-Ae Lee, Ki-Suk Kim, Janghwan Kim, Chang Woo Song, Seokjoo Yoon
      Given the rapid growth of engineered and customer products made of silver nanoparticles (Ag NPs), understanding their biological and toxicological effects on humans is critically important. The molecular developmental neurotoxic effects associated with exposure to Ag NPs were analyzed at the physiological and molecular levels, using an alternative cell model: human embryonic stem cell (hESC)-derived neural stem/progenitor cells (NPCs). In this study, the cytotoxic effects of Ag NPs (10–200μg/ml) were examined in these hESC-derived NPCs, which have a capacity for neurogenesis in vitro, at 6 and 24h. The results showed that Ag NPs evoked significant toxicity in hESC-derived NPCs at 24h in a dose-dependent manner. In addition, Ag NPs induced cell cycle arrest and apoptosis following a significant increase in oxidative stress in these cells. To further clarify the molecular mechanisms of the toxicological effects of Ag NPs at the transcriptional and post-transcriptional levels, the global expression profiles of genes and miRNAs were analyzed in hESC-derived NPCs after Ag NP exposure. The results showed that Ag NPs induced oxidative stress and dysfunctional neurogenesis at the molecular level in hESC-derived NPCs. Based on this hESC-derived neural cell model, these findings have increased our understanding of the molecular events underlying developmental neurotoxicity induced by Ag NPs in humans.


      PubDate: 2016-03-26T12:39:43Z
       
  • Inhibition of the aryl hydrocarbon receptor prevents Western diet-induced
           obesity. Model for AHR activation by kynurenine via oxidized-LDL, TLR2/4,
           TGFβ, and IDO1
    • Abstract: Publication date: Available online 25 March 2016
      Source:Toxicology and Applied Pharmacology
      Author(s): Benjamin J. Moyer, Itzel Y. Rojas, Joanna S. Kerley-Hamilton, Haley F. Hazlett, Krishnamurthy V. Nemani, Heidi W. Trask, Rachel J. West, Leslie E. Lupien, Alan J. Collins, Carol S. Ringelberg, Barjor Gimi, William B. Kinlaw, Craig R. Tomlinson
      Obesity is an increasingly urgent global problem, yet, little is known about its causes and less is known how obesity can be effectively treated. We showed previously that the aryl hydrocarbon receptor (AHR) plays a role in the regulation of body mass in mice fed Western diet. The AHR is a ligand-activated nuclear receptor that regulates genes involved in a number of biological pathways, including xenobiotic metabolism and T cell polarization. This study was an investigation into whether inhibition of the AHR prevents Western diet-based obesity. Male C57Bl/6J mice were fed control and Western diets with and without the AHR antagonist α-naphthoflavone or CH-223191, and a mouse hepatocyte cell line was used to delineate relevant cellular pathways. Studies are presented showing that the AHR antagonists α-naphthoflavone and CH-223191 significantly reduce obesity and adiposity and ameliorates liver steatosis in male C57Bl/6J mice fed a Western diet. Mice deficient in the tryptophan metabolizing enzyme indoleamine 2,3-dioxygenase 1 (IDO1) were also resistant to obesity. Using an AHR-directed, luciferase-expressing mouse hepatocyte cell line, we show that the transforming growth factor β1 (TGFβ1) signaling pathway via PI3K and NF-κB and the toll-like receptor 2/4 (TLR2/4) signaling pathway stimulated by oxidized low-density lipoproteins via NF-κB, each induce luciferase expression; however, TLR2/4 signaling was significantly reduced by inhibition of IDO1. At physiological levels, kynurenine but not kynurenic acid (both tryptophan metabolites and known AHR agonists) activated AHR-directed luciferase expression. We propose a hepatocyte-based model, in which kynurenine production is increased by enhanced IDO1 activity stimulated by TGFβ1 and TLR2/4 signaling, via PI3K and NF-κB, to perpetuate a cycle of AHR activation to cause obesity; and inhibition of the AHR, in turn, blocks the cycle's output to prevent obesity. The AHR, with its broad ligand binding specificity, is a promising candidate for a potentially simple therapeutic approach for the prevention and treatment of obesity and associated complications.
      Graphical abstract image

      PubDate: 2016-03-26T12:39:43Z
       
  • Editorial Board
    • Abstract: Publication date: 15 May 2016
      Source:Toxicology and Applied Pharmacology, Volume 299




      PubDate: 2016-03-26T12:39:43Z
       
  • The concept of bio-corona in modulating the toxicity of engineered
           nanomaterials (ENM)
    • Abstract: Publication date: 15 May 2016
      Source:Toxicology and Applied Pharmacology, Volume 299
      Author(s): Dana Westmeier, Roland H. Stauber, Dominic Docter
      Besides the wide use of engineered nanomaterials (ENM) in technical products, their application spectrum in biotechnology and biomedicine is steadily increasing. In complex physiological environments the physico-chemical properties and the behavior of nanoparticles (NPs) are challenging to characterize. Biomolecules rapidly adsorb to the nanomaterial, leading to the formation of the protein/biomolecule corona, which critically affects the nanomaterials' (patho)biological and technical identities. This formation can trigger an immune response and affect nanoparticles' toxicity and targeting capabilities. In this review, we provide a survey of recent findings on the (protein)corona-nanoparticle interaction and discuss how the corona modulates both cytotoxicity and the immune response as well as to improve the efficacy of targeted delivery of nanocarriers.


      PubDate: 2016-03-26T12:39:43Z
       
  • Enzymatic oxidative biodegradation of nanoparticles: Mechanisms,
           significance and applications
    • Abstract: Publication date: 15 May 2016
      Source:Toxicology and Applied Pharmacology, Volume 299
      Author(s): Irina I. Vlasova, Alexandr A. Kapralov, Zachary P. Michael, Seth C. Burkert, Michael R. Shurin, Alexander Star, Anna A. Shvedova, Valerian E. Kagan
      Biopersistence of carbon nanotubes, graphene oxide (GO) and several other types of carbonaceous nanomaterials is an essential determinant of their health effects. Successful biodegradation is one of the major factors defining the life span and biological responses to nanoparticles. Here, we review the role and contribution of different oxidative enzymes of inflammatory cells – myeloperoxidase, eosinophil peroxidase, lactoperoxidase, hemoglobin, and xanthine oxidase – to the reactions of nanoparticle biodegradation. We further focus on interactions of nanomaterials with hemoproteins dependent on the specific features of their physico-chemical and structural characteristics. Mechanistically, we highlight the significance of immobilized peroxidase reactive intermediates vs diffusible small molecule oxidants (hypochlorous and hypobromous acids) for the overall oxidative biodegradation process in neutrophils and eosinophils. We also accentuate the importance of peroxynitrite-driven pathways realized in macrophages via the engagement of NADPH oxidase- and NO synthase-triggered oxidative mechanisms. We consider possible involvement of oxidative machinery of other professional phagocytes such as microglial cells, myeloid-derived suppressor cells, in the context of biodegradation relevant to targeted drug delivery. We evaluate the importance of genetic factors and their manipulations for the enzymatic biodegradation in vivo. Finally, we emphasize a novel type of biodegradation realized via the activation of the “dormant” peroxidase activity of hemoproteins by the nano-surface. This is exemplified by the binding of GO to cyt c causing the unfolding and ‘unmasking’ of the peroxidase activity of the latter. We conclude with the strategies leading to safe by design carbonaceous nanoparticles with optimized characteristics for mechanism-based targeted delivery and regulatable life-span of drugs in circulation.


      PubDate: 2016-03-26T12:39:43Z
       
  • Developmental toxicity of engineered nanomaterials in rodents
    • Abstract: Publication date: 15 May 2016
      Source:Toxicology and Applied Pharmacology, Volume 299
      Author(s): Makoto Ema, Masashi Gamo, Kazumasa Honda
      We summarized significant effects reported in the literature on the developmental toxicity of engineered nanomaterials (ENMs) in rodents. The developmental toxicity of ENMs included not only structural abnormalities, but also death, growth retardation, and behavioral and functional abnormalities. Most studies were performed on mice using an injection route of exposure. Teratogenic effects were indicated when multi-walled carbon nanotubes (MWCNTs), single-walled carbon nanotubes (SWCNTs), and TiO2-nanoparticles were administered to mice during early gestation. Reactive oxygen species levels were increased in placentas and malformed fetuses and their placentas after prenatal exposure to MWCNTs and SWCNTs, respectively. The pre- and postnatal mortalities and growth retardation in offspring increased after prenatal exposure to ENMs. Histopathological and functional abnormalities were also induced in placentas after prenatal exposure to ENMs. Maternal exposure to ENMs induced behavioral alterations, histopathological and biochemical changes in the central nervous system, increased susceptibility to allergy, transplacental genotoxicity, and vascular, immunological, and reproductive effects in offspring. The size- and developmental stage-dependent placental transfer of ENMs was noted after maternal exposure. Silver accumulated in the visceral yolk sac after being injected with Ag-NPs during early gestation. Although currently available data has provided initial information on the potential developmental toxicity of ENMs, that on the developmental toxicity of ENMs is still very limited. Further studies using well-characterized ENMs, state-of the-art study protocols, and appropriate routes of exposure are required in order to clarify these developmental effects and provide information suitable for risk assessments of ENMs.


      PubDate: 2016-03-26T12:39:43Z
       
  • Nanotoxicology ten years later: Lights and shadows
    • Abstract: Publication date: 15 May 2016
      Source:Toxicology and Applied Pharmacology, Volume 299
      Author(s): Anna Shvedova, Antonio Pietroiusti, Valerian Kagan
      The mounting societal concerns about possible and maybe even likely adverse effects of nanomaterials are reflected in a large and growing number of publications in the field of nanotoxicology. Indeed, today's search in PubMed reveals >3700 publications on the subject denoted by (toxic+nanomaterials) – quite a growth over the last decade that began with only two dozens of them up-to 2005.


      PubDate: 2016-03-26T12:39:43Z
       
  • Grouping nanomaterials to predict their potential to induce pulmonary
           inflammation
    • Abstract: Publication date: 15 May 2016
      Source:Toxicology and Applied Pharmacology, Volume 299
      Author(s): Hedwig M. Braakhuis, Agnes G. Oomen, Flemming R. Cassee
      The rapidly expanding manufacturing, production and use of nanomaterials have raised concerns for both worker and consumer safety. Various studies have been published in which induction of pulmonary inflammation after inhalation exposure to nanomaterials has been described. Nanomaterials can vary in aspects such as size, shape, charge, crystallinity, chemical composition, and dissolution rate. Currently, efforts are made to increase the knowledge on the characteristics of nanomaterials that can be used to categorise them into hazard groups according to these characteristics. Grouping helps to gather information on nanomaterials in an efficient way with the aim to aid risk assessment. Here, we discuss different ways of grouping nanomaterials for their risk assessment after inhalation. Since the relation between single intrinsic particle characteristics and the severity of pulmonary inflammation is unknown, grouping of nanomaterials by their intrinsic characteristics alone is not sufficient to predict their risk after inhalation. The biokinetics of nanomaterials should be taken into account as that affects the dose present at a target site over time. The parameters determining the kinetic behaviour are not the same as the hazard-determining parameters. Furthermore, characteristics of nanomaterials change in the life-cycle, resulting in human exposure to different forms and doses of these nanomaterials. As information on the biokinetics and in situ characteristics of nanomaterials is essential but often lacking, efforts should be made to include these in testing strategies. Grouping nanomaterials will probably be of the most value to risk assessors when information on intrinsic characteristics, life-cycle, biokinetics and effects are all combined.


      PubDate: 2016-03-26T12:39:43Z
       
  • Discovery of unique and ENM— specific pathophysiologic pathways:
           Comparison of the translocation of inhaled iridium nanoparticles from
           nasal epithelium versus alveolar epithelium towards the brain of rats
    • Abstract: Publication date: 15 May 2016
      Source:Toxicology and Applied Pharmacology, Volume 299
      Author(s): Wolfgang G. Kreyling
      The biokinetics of inhaled nanoparticles (NP) is more complex than that of larger particles since NP may NP deposited on the nasal mucosa of the upper respiratory tract (URT) may translocate to the olfactory bulb of the brain and also via the trigeminus (URT neuronal route); and (b) NP deposited in the lower respiratory tract (LRT) may cross the ABB into blood and enter the brain across the blood-brain-barrier (BBB) or take a neuronal route from enervated tracheo-bronchial epithelia via the vagus nerve. Translocation from both - the URT and the LRT - are quantified during the first 24h after a 1-hour aerosol inhalation of 20nm-sized, 192Ir radiolabeled iridium NP by healthy adult rats using differential exposures: (I) nose-only exposure of the entire respiratory tract or (II) intratracheal (IT) inhalation of intubated and ventilated rats, thereby bypassing the URT and extrathoracic nasal passages. After nose-only exposure brain accumulation (BrAcc) is significantly nine-fold higher than after IT inhalation since the former results from both pathways (a+b) while the latter exposure comes only from pathway (b). Interestingly, there are significantly more circulating NP in blood 24h after nose-only inhalation than after IT inhalation. Distinguishing translocation from URT versus LRT estimated from the differential inhalation exposures, the former is significantly higher (8-fold) than from the LRT. Although the BrAcc fraction is rather low compared to total NP deposition after this short-term exposure, this study proofs that inhaled insoluble NP can accumulate in the brain from both – URT and LRT which may trigger and/or modulate adverse health effects in the central nervous system (CNS) during chronic exposure.
      Graphical abstract image

      PubDate: 2016-03-26T12:39:43Z
       
  • Goniothalamin prevents the development of chemically induced and
           spontaneous colitis in rodents and induces apoptosis in the HT-29 human
           colon tumor cell line
    • Abstract: Publication date: Available online 22 March 2016
      Source:Toxicology and Applied Pharmacology
      Author(s): Débora Barbosa Vendramini-Costa, Antonio Alcaide, Karin Juliane Pelizzaro-Rocha, Elena Talero, Javier Ávila-Román, Sofia Garcia-Mauriño, Ronaldo Aloise Pilli, João Ernesto de Carvalho, Virginia Motilva
      Colon cancer is the third most incident type of cancer worldwide. One of the most important risk factors for colon cancer development are inflammatory bowel diseases (IBD), thus therapies focusing on IBD treatment have great potential to be used in cancer prevention. Nature has been a source of new therapeutic and preventive agents and the racemic form of the styryl-lactone goniothalamin (GTN) has been shown to be a promising antiproliferative agent, with gastroprotective, antinociceptive and anti-inflammatory effects. As inflammation is a well-known tumor promoter, the major goal of this study was to evaluate the therapeutic and preventive potentials of GTN on chemically induced and spontaneous colitis, as well as the cytotoxic effects of GTN on a human colon tumor cell line (HT-29). GTN treatments inhibited TNBS-induced acute and chronic colitis development in Wistar rats, reducing myeloperoxidase levels and inflammatory cells infiltration in the mucosa. In spontaneous-colitis using IL-10 deficient mice (C57BL/6 background), GTN prevented colitis development through downregulation of TNF-α, upregulation of SIRT-1 and inhibition of proliferation (PCNA index), without signs of toxicity after three months of treatment. In HT-29 cells, treatment with 10μM of GTN induced apoptosis by increasing BAX/BCL2, p-JNK1/JNK1, p-P38/P38 ratios as well as through ROS generation. Caspase 8, 9 and 3 activation also occurred, suggesting caspase-dependent apoptotic pathway, culminating in PARP-1 cleavage. Together with previous data, these results show the importance of GTN as a pro-apoptotic, preventive and therapeutic agent for IBD and highlight its potential as a chemopreventive agent for colon cancer.


      PubDate: 2016-03-22T12:31:48Z
       
 
 
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