Bridged Biaryl Atropisomers by Organocatalyzed Kinetic Asymmetric Alcoholysis.

We disclose herein an asymmetric synthesis of axially chiral oxazepine-containing bridged biaryls via CPA-catalyzed kinetic asymmetric alcoholysis. Control experiments showed that this CPA-catalyzed alcoholysis was reversible, and lowering the reaction temperature could almost suppress the reversible reaction, thus providing a series of axially chiral oxazepine-containing bridged biaryl compounds in good to excellent enantioselectivities. The gram-scale reactions and facile derivatizations of the enantioenriched products demonstrate the practical utility of this reaction.

Chiral Brønsted Acid-Catalyzed Kinetic Resolution of Sulfoximines for the Synthesis of Benzothiadiazine-1-Oxides.

Benzothiadiazine-1-oxide scaffolds with S-stereogenic centers are prevalent in bioactive and pharmaceutical molecules. Reported works mainly focused on the metal-catalyzed asymmetric C-H amination/cyclization reaction for the synthesis of benzothiadiazine-1-oxides. Here, we reported a chiral phosphoric acid-catalyzed kinetic resolution of sulfoximines, providing chiral benzothiadiazine-1-oxides and recovered chiral sulfoximines with moderate to good enantioselectivities (s factors up to 36.6).

Effect of magnetic fields on the structure, properties, baking performance of frozen wheat dough at different frozen stage.

As an emerging physical technology, magnetic fields have been used to improve the quality of frozen and refrigerated foods. This study compared the effect of applying a static magnetic field (2 mT) at different stages of freezing and storage on the quality of frozen dough. Results suggested that the magnetic field significantly impacted frozen dough quality. It not only prevented the formation of ice crystals during the pre-freezing stage but also inhibited ice crystal growth during the following frozen storage. This effect helped to maintain the integrity of gluten proteins and their adhesion to starch granules by preventing the breakage of disulfide bonds and the depolymerization of gluten macromolecules. It was also observed that yeast inactivation and glutathione release were reduced, resulting in improved air retention and air production capacity of the dough. This, in turn, led to a more appealing volume and texture quality of the finished bread.

Improving microbial production of value-added products through the intervention of magnetic fields.

The magnetic field application is emerging as an auxiliary physical strategy to facilitate rapid biomass accumulation and intracellular production of compounds. However, the underlying mechanisms and principles governing the application of magnetic fields for microbial growth and biotransformation are not yet fully understood. Therefore, a better understanding of interdisciplinary technologies integration, expanded magnetic field application, and scaled-up industrial implementation is crucial. In this review, the magnetic field characteristics, magnetic field-assisted fermentation devices, and the working mechanism of magnetic field have been reviewed comprehensively from both physical and microbiological perspectives. The review suggests that magnetic fields affect the biochemical processes in microorganisms by mediating nutrient transport across membranes, electron transfer during photosynthesis and respiration, enzyme activity and gene expression. Moreover, the recent advances in magnetic field application for microbial fermentation and conversion in biochemical, food and agricultural fields have been summarized.

Chiral Phosphoric Acid Catalyzed Asymmetric Hydrolysis of Biaryl Oxazepines for the Synthesis of Axially Chiral Biaryl Amino Phenol Derivatives.

The development of catalytic asymmetric reaction with water as the reactant is challenging due to the reactivity- and stereoselectivity-control issues resulted from the low nucleophilicity and the small size of water. We disclose herein a chiral phosphoric acid (CPA) catalyzed atroposelective ring-opening reaction of biaryl oxazepines with water. A series of biaryl oxazepines undergo the CPA catalyzed asymmetric hydrolysis in a highly enantioselective manner. The key for the success of this reaction is the use of a new SPINOL-derived CPA catalyst and the high reactivity of biaryl oxazepine substrates towards water under acidic conditions. Density functional theory calculations suggest that the reaction proceeds via a dynamic kinetic resolution pathway and the CPA catalyzed addition of water to the imine group is both enantio- and rate-determining.

pH-sensitive tumor-tropism hybrid membrane-coated nanoparticles for reprogramming the tumor microenvironment and boosting the antitumor immunity.

Metabolic dysregulation contributes not only to cancer development but also to a tumor immune microenvironment (TIME), which poses great challenges to chemo- and immunotherapy. Targeting metabolic reprogramming has recently emerged as a promising strategy for cancer treatment, but the lethality against solid tumors appears to be fairly restricted, partially due to the poor solubility of small molecule drugs. Herein, we construct a versatile biomimetic nanoplatform (referred to as HM-BPT) employing pH-sensitive tumor-tropism hybrid membrane-coated Manganese oxide (MnO2) nanoparticles for the delivery of BPTES, a glutamine metabolism inhibitor. Basically, hybrid membranes consisting of mesenchymal stem cell membranes (MSCm) and pH-sensitive liposomes (pSL) enable the biomimetic nanoplatform to target TME and escape from endo/lysosomes after endocytosis. The results reveal that HM-BPT treatment leads to remarkable tumor inhibition, cytotoxic T lymphocyte (CTL) infiltration, as well as M1 phenotype repolarization and stimulator of IFN genes (STING) pathway activation in macrophages in a 4T1 xenograft model. Furthermore, glutathione (GSH) depletion and oxygen (O2) supply synergistically ameliorate the immunosuppressive status of the TME, boosting potent antitumor immune responses. Overall, our study explores an integrated therapeutic platform for TME reprogramming and immune activation, offering tremendous promise for cancer combination therapy. STATEMENT OF SIGNIFICANCE: Metabolic abnormalities and the tumor immune microenvironment (TIME) lead to hyporesponsiveness to conventional therapies, ultimately resulting in refractory malignancies. In the current work, a biomimetic nanoplatform (HM-BPT) was developed for TME metabolic reprogramming in favor of immunotherapy. Particularly, hybrid membrane camouflage endowed the nanoplatform with TME targeting, endo/lysosomal escape, and sensitive release properties. The impact of hybrid membrane fusion ratio on cellular uptake and cell viability was explored, yielding beneficial references for the future development of bioactive nanomaterials. Intravenous administration of HM-BPT substantially relieved tumor burden and restored innate and acquired immune activation in 4T1 xenograft models. In conclusion, the created HM-BPT system has the potential to be a promising nanoplatform for combining cancer therapies.

Leukocyte Immunoglobulin-like Receptor A5 Deletion Aggravates the Pathogenesis of Pseudomonas aeruginosa Keratitis by Promoting Proinflammatory Cytokines.

PURPOSE: The purpose of this study was to assess the role of leukocyte immunoglobulin-like receptor A5 (LILRA5) in regulating bacterial infection and corneal inflammation. METHODS: The human corneal tissue microarray data set GSE58291 from Gene Expression Omnibus was downloaded. Then, the differentially expressed genes, Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, Gene Set Enrichment Analysis, and the immune infiltration analysis were conducted. We constructed the Pseudomonas aeruginosa ( P. aeruginosa ) keratitis mice model using wild-type and LILRA5-deficient mice. The results of the bioinformatics analysis were verified by the cell in vitro and animal in vivo experiments. RESULTS: This study revealed that LILRA5 is substantially expressed in human keratitis and regulates the immune response negatively. Neutrophils were identified as the core fraction of immune cells in keratitis. After P. aeruginosa infection, neutrophils lacking LILRA5 induced elevated levels of proinflammatory cytokines and toll-like receptor 4. LILRA5 deficiency exacerbated the severity of the infection and the production of proinflammatory cytokines in mice. CONCLUSIONS: LILRA5 was discovered as an immunosuppressive regulator in P. aeruginosa keratitis, highlighting its significance in activated immune responses.

Atroposelective Access to 1,3-Oxazepine-Containing Bridged Biaryls via Carbene-Catalyzed Desymmetrization of Imines.

We disclose herein an atroposelective synthesis of novel bridged biaryls containing medium-sized rings via N-heterocyclic carbene organocatalysis. The reaction starts with addition of the carbene catalyst to the aminophenol-derived aldimine substrate. Subsequent oxidation and intramolecular desymmetrization lead to the formation of 1,3-oxazepine-containing bridged biaryls in good yields and excellent enantioselectivities. These novel bridged biaryl products can be readily transformed into chiral phosphite ligands. Preliminary density function theory calculations suggest that the origin of enantioselectivity arises from the more favorable frontier molecular orbital interactions in the transition state leading to the major product.

Main components of free organic carbon generated by obligate chemoautotrophic bacteria that inhibit their CO2 fixation.

Chemoautotrophic bacteria play an important role in combating the rise in global CO2. However, recently it was found that extracellular free organic carbon (EFOC) generated by chemoautotrophic bacteria inhibits their CO2 fixation. Although continuous-flow membrane bioreactor can remove EFOC and enrich bacteria, it may also remove beneficial bio-factors for bacterial growth. Finding out the main inhibitory factors and inhibitory mechanisms in EFOC can provide theoretical guidance for the development of targeted inhibitory component removal technology. The results show a significant negative correlation between the increasing proportion of small-molecule EFOC and the decreasing trend of CO2 fixation efficiency, and simulation experiments confirm that the small molecule organics such as amino acids and organic acids are the main components of EFOC that inhibit CO2 fixation by inhibiting ribulose bisphosphate carboxylase/oxygenase (RuBisCO) gene (cbb) transcription efficiency. Therefore, amino acids and organic acids are suggested to be recovered to promote efficient CO2 fixation of autotrophic bacteria.

Antibody Responses and the Effects of Clinical Drugs in COVID-19 Patients.

The coronavirus disease 2019 (COVID-19) emerged around December 2019 and have become a global epidemic disease currently. Specific antibodies against SAS-COV-2 could be detected in COVID-19 patients' serum or plasma, but the clinical values of these antibodies as well as the effects of clinical drugs on humoral responses have not been fully demonstrated. In this study, 112 plasma samples were collected from 36 patients diagnosed with laboratory-confirmed COVID-19 in the Fifth Affiliated Hospital of Sun Yat-sen University. The IgG and IgM antibodies against receptor binding domain (RBD) and spike protein subunit 1 (S1) of SAS-COV-2 were detected by ELISA. We found that COVID-19 patients generated specific antibodies against SARS-CoV-2 after infection, and the levels of anti-RBD IgG within 2 to 3 weeks from onset were negatively associated with the time of positive-to-negative conversion of SARS-CoV-2 nucleic acid. Patients with severe symptoms had higher levels of anti-RBD IgG in 2 to 3 weeks from onset. The use of chloroquine did not significantly influence the patients' antibody titer but reduced C-reaction protein (CRP) level. Using anti-viral drugs (lopinavir/ritonavir or arbidol) reduced antibody titer and peripheral lymphocyte count. While glucocorticoid therapy developed lower levels of peripheral lymphocyte count and higher levels of CRP, lactate dehydrogenase (LDH), α-Hydroxybutyrate dehydrogenase(α-HBDH), total bilirubin (TBIL), direct bilirubin (DBIL). From these results, we suggested that the anti-RBD IgG may provide an early protection of host humoral responses against SAS-COV-2 infection within 2 to 3 weeks from onset, and clinical treatment with different drugs displayed distinct roles in humoral and inflammatory responses.

Tetrahedral DNA Nanostructures Inhibit Ferroptosis and Apoptosis in Cisplatin-induced Renal Injury.

Acute kidney injury (AKI) is the most serious adverse reaction during cisplatin chemotherapy, which limits the drug's clinical effects. Therefore, effective strategies for protective therapy need to be developed. In the current study, we verified that tetrahedral DNA nanostructures (TDNs), promising DNA nano biomaterials, played protective roles against cisplatin-induced death of renal tubular cells. Herein, we observed that TDNs decreased the generation of lipid reactive oxygen species (ROS), restored the down-regulation of glutathione peroxidase 4 (GPX4), and hence inhibited ferroptosis induced by RSL3, a typical inducer of ferroptosis. In addition, we proved that TDNs attenuated cisplatin-induced ferroptosis by reversing the down-regulation of GPX4 and attenuated apoptosis induced by cisplatin via reducing the cleavage of poly(ADP-ribose) polymerase (PARP). Taking this all into account, our investigation suggested the potential of TDNs for cisplatin-induced AKI therapy.

Sirtuin1 activator SRT2183 suppresses glioma cell growth involving activation of endoplasmic reticulum stress pathway.

BACKGROUND: Glioblastoma (GBM) is an extremely deadly form of brain cancer with limited treatment options and thus novel therapeutic modalities are necessary. Histone deacetylase inhibitors (HDACi) have demonstrated clinical and preclinical activities against GBM. (Silent mating type information regulation 2 homolog, Sirt1) abbreviated as Sirtuin 1, has been implicated in GBM. We explored the activity of the Sirt1 activator SRT2183 in glioma cell lines in terms of biological response. METHODS: The effects of SRT2183 on glioma cell growth and neurosphere survival were evaluated in vitro using the CCK-8, clonogenic and neurosphere assays, respectively. Glioma cell cycle arrest and apoptosis were determined by flow cytometry. SRT2183-induced autophagy was investigated by detection of GFP-microtubule-associated protein 1 light chain 3 (GFP-LC3) puncta, conversion of the nonlipidated form of LC3 (LC3-I) to the phosphatidylethanolamine-conjugated form (LC3-II). Acetylation of STAT3 and NF-κB in SRT2183-treated glioma cells was examined using immunoprecipitation. The expression levels of anti-apoptotic proteins were assayed by immunoblotting. RESULTS: SRT2183 suppressed glioma cell growth and destroyed neurospheres in vitro. Furthermore, SRT2183 induced glioma cell cycle arrest and apoptosis, accompanying by upregulation of the pro-apoptotic Bim and downregulation of Bcl-2 and Bcl-xL. Notably, ER stress was triggered in glioma cells upon exposure to SRT2183 while the pre-exposure to 4-PBA, an ER stress inhibitor, significantly antagonized SRT2183-mediated growth inhibition in glioma cells. In addition, SRT2183 induced autophagy in glioma cells and pharmacological modulation of autophagy appeared not to affect SRT2183-inhibited cell growth. Of interest, the acetylation and phosphorylation of p65 NF-κB and STAT3 in glioma cells were differentially affected by SRT2183. CONCLUSIONS: Our data suggest the ER stress pathway is involved in SRT2183-mediated growth inhibition in glioma. Further investigation in vivo is needed to consolidate the data.

Transcriptomic analyses reveal the molecular mechanisms of schisandrin B alleviates CCl4-induced liver fibrosis in rats by RNA-sequencing.

Liver fibrosis is a progression of chronic liver disease with lacks effective therapies at present. Schisandrin B (Sch B), a bioactive compound extracted from the traditional Chinese medicine Schisandra chinensis, was reported to benefit liver diseases. This study aimed to investigate the therapeutic effects and molecular mechanisms of Sch B against CCl4-induced liver fibrosis in rats. RNA sequencing and transcriptome analysis were performed collaboratively, including analysis of differential gene expression, gene ontology (GO) analysis, pathway analysis and pathway-act-network analysis. The results demonstrated that Sch B effectively alleviated CCl4-induced liver damage and fibrosis in rats, as evidenced by improved liver function and decreased extracellular matrix deposition. Furthermore, 4440 (1878 up-regulated, 2562 down-regulated) genes in the model group versus (vs) normal group, 4243 (2584 up-regulated, 1659 down-regulated) genes in Sch B-treated group vs model group were identified as differentially expressed genes (DEGs). Subsequently, GO analysis revealed that DEGs were mainly enriched in metabolism, oxidation-reduction, endoplasmic reticulum stress and apoptosis-related biological processes. Pathway analysis suggested that Sch B up-regulated cytochrome P450 drug metabolism, PPAR signaling pathways, and down-regulated glutathione metabolism pathways. In addition, the regulatory patterns of Sch B on key genes and pathways were also confirmed. In conclusion, our study demonstrated Sch B alleviated CCl4-induced liver fibrosis by multiple modulatory mechanisms, which provide new clues for further pharmacological study of Sch B.

A Frizzled-Like Cysteine-Rich Domain in Glypican-3 Mediates Wnt Binding and Regulates Hepatocellular Carcinoma Tumor Growth in Mice.

Wnt signaling is one of the key regulators of hepatocellular carcinoma (HCC) tumor progression. In addition to the classical receptor frizzled (FZD), various coreceptors including heparan sulfate proteoglycans (HSPGs) are involved in Wnt activation. Glypican-3 (GPC3) is an HSPG that is overexpressed in HCC and functions as a Wnt coreceptor that modulates HCC cell proliferation. These features make GPC3 an attractive target for liver cancer therapy. However, the precise interaction of GPC3 and Wnt and how GPC3, Wnt, and FZD cooperate with each other are poorly understood. In this study, we established a structural model of GPC3 containing a putative FZD-like cysteine-rich domain at its N-terminal lobe. We found that F41 and its surrounding residues in GPC3 formed a Wnt-binding groove that interacted with the middle region located between the lipid thumb domain and the index finger domain of Wnt3a. Mutating residues in this groove significantly inhibited Wnt3a binding, ß-catenin activation, and the transcriptional activation of Wnt-dependent genes. In contrast with the heparan sulfate chains, the Wnt-binding groove that we identified in the protein core of GPC3 seemed to promote Wnt signaling in conditions when FZD was not abundant. Specifically, blocking this domain using an antibody inhibited Wnt activation. In HCC cells, mutating residue F41 on GPC3 inhibited activation of ß-catenin in vitro and reduced xenograft tumor growth in nude mice compared with cells expressing wild-type GPC3. Conclusion: Our investigation demonstrates a detailed interaction of GPC3 and Wnt3a, reveals the precise mechanism of GPC3 acting as a Wnt coreceptor, and provides a potential target site on GPC3 for Wnt blocking and HCC therapy.

Asiatic acid ameliorates CCl4-induced liver fibrosis in rats: involvement of Nrf2/ARE, NF-κB/IκBα, and JAK1/STAT3 signaling pathways.

PURPOSE: Currently, there are no effective therapies for liver fibrosis; hence, the development of anti-liver fibrosis agents is urgently needed. Here, we attempted to investigate the therapeutic effect and mechanism of asiatic acid (AA) on liver fibrosis, mainly focusing on the impact of AA on nuclear erythroid 2-related factor 2/antioxidant response element (Nrf2/ARE), nuclear factor-kappa B (NF-κB)/IκBα, and JAK1/signal transducer and activator of transcription 3 (STAT3) signaling pathways. METHODS: Rats were induced liver fibrosis by carbon tetrachloride (CCl4) for 6 weeks and concomitantly treated with AA (5 and 15 mg/kg) or vehicle by daily gavage. After AA treatment, the morphology of liver tissue was analyzed by H&E and Masson's trichrome staining, and serum biochemical indicators were also assayed. Thereafter, the protein levels of Nrf2, HO-1, NQO-1, GCLC, NF-κB, IκBα, JAK1, p-JAK1, STAT3, and p-STAT3 were determined by Western blotting. RESULTS: Our results showed that AA treatment dramatically ameliorated CCl4-induced oxidative stress, inflammation, and fibrosis in rats. The expression of nuclear Nrf2 was increased after AA treatment, whereas cytoplasm Nrf2 levels were decreased. The protein expression of Nrf2 target proteins including HO-1, NQO-1, and GCLC was significantly increased by AA treatment. Furthermore, AA treatment decreased the levels of nuclear NF-κB to inhibit NF-κB/IκBα signaling pathway. In addition, we also found that AA treatment regulated JAK1/STAT3 signaling by decreasing the phosphorylation levels of JAK1 and STAT3. CONCLUSION: These results demonstrate that AA ameliorates CCl4-induced liver fibrosis in rats by regulating Nrf2/ARE, NF-κB/IκBα, and JAK1/STAT3 signaling pathways, which suggests that AA might be a new antifibrosis agent that improves liver fibrosis.

Oncolytic Newcastle disease virus induces autophagy-dependent immunogenic cell death in lung cancer cells.

In addition to direct oncolysis, oncolytic viruses trigger immunogenic cell death (ICD) and primes antitumor immunity. We have previously shown that oncolytic Newcastle disease virus (NDV), strain FMW (NDV/FMW), induces apoptosis and/or autophagy in cancer cells. In this study, we investigated whether oncolytic NDV can induce ICD in lung cancer cells and whether apoptosis or autophagy plays a role in NDV-triggered ICD. To this end, we examined cell surface expression of calreticulin (CRT) on NDV-infected lung cancer cells and measured ICD determinants, high mobility group box 1 (HMGB1), heat shock protein 70/90 (HSP70/90) and ATP in supernatants following viral infection. Flow cytometric analysis using anti-CRT antibody and PI staining of NDV-infected lung cancer cells showed an increase in the number of viable (propidium iodide-negative) cells, suggesting the induction of CRT exposure upon NDV infection. In addition, confocal and immunoblot analysis using anti-CRT antibody showed that an enhanced accumulation of CRT on the cell surface of NDV-infected cells, indicating the translocation of CRT to the cell membrane upon NDV infection. We further demonstrated that NDV infection induced the release of secreted HMGB1 and HSP70/90 by examining the concentrated supernatants of NDV-infected cells. Furthermore, pre-treatment with either the pan-caspase inhibitor z-VAD-FMK or the necrosis inhibitor Necrostain-1, had no impact on NDV-induced release of ICD determinants in lung cancer cells. Rather, depletion of autophagy-related genes in lung cancer cells significantly inhibited the induction of ICD determinants by NDV. Of translational importance, in a lung cancer xenograft model, treatment of mice with supernatants from NDV-infected cells significantly inhibited tumour growth. Together, these results indicate that oncolytic NDV is a potent ICD-inducer and that autophagy contributes to NDV-mediated induction of ICD in lung cancer cells.

Asiatic acid attenuates CCl4-induced liver fibrosis in rats by regulating the PI3K/AKT/mTOR and Bcl-2/Bax signaling pathways.

Liver fibrosis is a major pathological feature of chronic liver diseases, and effective therapies are limited at present. Asiatic acid (AA) is a triterpenoid isolated from Centella asiatica, which exhibits efficient anti-inflammatory and anti-oxidative activities. In this study, we attempted to evaluate the potential therapeutic effect of AA on CCl4-induced liver fibrosis in rats and to investigate the underlying molecular mechanisms. Liver fibrosis-related indexes including body weight, biochemical parameters, histological changes, the mRNA expression levels of inflammatory cytokines and biomarkers, and changes in the expression of related proteins in liver tissue were assessed. The results showed that AA treatment effectively ameliorated CCl4-induced liver injury and fibrosis. Mechanistically, AA treatment attenuated CCl4-induced oxidative stress, inflammation, and hepatocyte apoptosis and regulated the Bcl-2/Bax signaling pathway in the liver. Additionally, we demonstrated that AA also inhibited hepatic stellate cell activation and extra cellular matrix (ECM) synthesis by regulating the PI3K/AKT/mTOR signaling pathway. In conclusion, these findings suggest that AA prevents the progression of liver fibrosis through multiple mechanisms and indicate that AA might be used for the treatment of liver fibrosis in the future.

PCB28 and PCB52 induce hepatotoxicity by impairing the autophagic flux and stimulating cell apoptosis in vitro.

Hepatotoxicity is one of the adverse health effects induced by polychlorinated biphenyls (PCBs). Recently, autophagy was revealed to play an important role in PCBs-induced toxicology, however, its precise role in PCBs-induced hepatotoxicity is as yet unknown. In this study, treatment of PCB28/PCB52 for 48 h dose-dependently induced hepatotoxicity at doses of 10, 20, 40 and 80 µM in homo and rattus hepatocytes. Expressions of proteins of BECN1, LC3-II and ULK1 significantly increased in PCB28/PCB52-treated cells at a dose of 40 µM, implying initiation of autophagy. Over-expression of p62 suggested deficient clearance of autophagosome. Consistently, accumulation of autophagosome was observed by transmission-electron microscopy and confocal fluorescence microscopy using adenovirus expressing mRFP-GFP-LC3, which may initiate apoptosis. Furthermore, increased reactive oxygen species levels might also induce autophagy and apoptosis. Consistently, cell apoptosis was evoked by the treatment of PCB28/PCB52 compared to the respective controls, which coincided with obvious hepatotoxicity. Subsequently, an inhibitor (3-methlyadenine) and an initiator (rapamycin) of autophagy were used. Compared to PCB28/PCB52 alone-treated cells, initiation of autophagy, blocked autophagic flux, cell apoptosis and hepatotoxicity were alleviated by 3-methlyadenine and aggravated by rapamycin, respectively. Taken together, PCB28 and PCB52 induced hepatotoxicity by impairing autophagic flux and stimulating cell apoptosis in vitro.

Induction of micronuclei and cell cycle arrest by some tri- and tetrachlorobiphenyls in mammalian cells deficient in xenobiotic-metabolizing enzymes.

Polychlorinated biphenyls (PCBs) are persistent organic pollutants with continued public health concerns. The lower chlorinated biphenyls are supposed to be mutagenic following metabolic activation. However, in a preliminary study, we recently observed induction of micronuclei by several PCBs in a subclone of Chinese hamster V79 cell line, V79-Mz, which is deficient in xenobiotic-metabolizing enzyme activities. In this study, metabolism-free genotoxicity of PCBs was investigated, using 10 tri- and tetrachlorobiphenyls, in V79, V79-Mz, and human hepatoma (HepG2) cell lines. Among the four tetrachlorobiphenyls, 2,4,4',5- and 2,3'4,4'-tetrachlorobiphenyl-both having a noncoplanar configuration-induced micronuclei in V79-Mz cells, while their coplanar analogs 3,4,4',5- and 3,3',4,4'-tetrachlorobiphenyl were inactive. Furthermore, 2,3,3'- (PCB 20) and 2,3,4'-trichlorobiphenyl (PCB 22) started to induce micronuclei in V79-Mz cells at 10 µM and higher concentrations, demonstrating more potent effects than observed with 2,2',3-, 2,2',4-, 2,2',5, and 2,4,4'-trichlorobiphenyl. As representative compounds, PCB 20 and 22 induced micronuclei in relatively high concentrations in HepG2 cells (p53-proficient), though they did not induce Hprt gene mutations in V79-Mz cells. PCB 20 and 22 increased mitotic index and induced cell cycle arrest at the G2/M phase, with effects more potent in V79-Mz than in V79 cells. This study suggests that 2,3,4'- and 2,3,3'-substituted PCBs are micronuclei inducers and G2/M arresters among a number of trichlorobiphenyls in mammalian cell lines, though with potency lower than that observed recently in V79-derived cells expressing human CYP2E1. Similarly, some noncoplanar tetrachlorobiphenyls possess metabolism-independent chromosome-damaging potentials. Environ. Mol. Mutagen. 58:199-208, 2017. © 2017 Wiley Periodicals, Inc.

Methamphetamine induces hepatotoxicity via inhibiting cell division, arresting cell cycle and activating apoptosis: In vivo and in vitro studies.

Methamphetamine (METH) resulted in acute hepatic injury. However, the underlying mechanisms have not been fully clarified. In the present study, rats were treated with METH (15 mg/kg B.W.) for 8 injections (i.p.), and the levels of alanine transaminase, asparatate transaminase and ammonia in serum were significantly elevated over those in the control group, suggesting hepatic injury, which was evidenced by histopathological observation. Analysis of the liver tissues with microarray revealed differential expressions of a total of 332 genes in METH-treated rats. According to the GO and KEGG annotations, a large number of down-regulated cell cycle genes were screened out, suggesting that METH induced cell cycle arrest and deficient of cell cycle checkpoint. Related genes and proteins were confirmed by RT-qPCR and western blotting in rat livers, respectively. Moreover, treatment of Brl-3A cells with METH caused significant cytotoxic response and marked cell cycle arrest. Furthermore, overexpressions of Cidea, cleaved caspase 3 and PARP 1 in METH-treated rats indicated activation of apoptosis, while its inhibition alleviated cell death in Brl-3A cells, suggesting that activation of apoptosis took an important role in METH-induced hepatotoxicity. Taken together, the present study demonstrates that METH induced hepatotoxicity via inducing cell cycle arrest and activating apoptosis.