Blockage of ROS-ERK-DLP1 signaling and mitochondrial fission alleviates Cr(VI)-induced mitochondrial dysfunction in L02 hepatocytes

Hexavalent chromium [Cr(VI)] is a common heavy metal pollutant widely used in various industrial fields. It is well known that mitochondria are the most vulnerable targets of heavy metals, but the key molecule/event that directly mediated mitochondrial dysfunction after Cr(VI) exposure is still unclear. The present study was aimed to explore whether Cr(VI) exposure could affect the mitochondrial fission/fusion process, and whether the related abnormal mitochondrial dynamics have been implicated in Cr(VI)-induced mitochondrial dysfunction. We found that the mitochondrial dysfunction caused by Cr(VI) exposure was characterized by decreased mitochondrial respiratory chain complex (MRCC) I/II activities and levels, collapsed mitochondrial membrane potential (MMP), depleted ATP, and increased reactive oxygen species (ROS) level. Cr(VI) induced abnormal mitochondrial fission/fusion events, the antioxidant Nacetyl-L-cysteine (NAC) restored the abnormal mitochondrial function as well as the fission/fusion dynamics. ROS was the up-stream regulator of extracellular regulated protein kinases (ERK) signaling, and the application of a specific ERK1/2 inhibitor PD98059 confirmed that activation of ERK1/2 signaling was associated with the abnormal mitochondrial fission/fusion and mitochondrial dysfunction. We also demonstrated that treatment with dynamic-like protein 1 (DLP1)-siRNA rescued mitochondrial dysfunction in Cr(VI)-exposed L02 hepatocytes. We reached the conclusion that blockage of ROS-ERK-DLP1 signaling and mitochondrial fission alleviates Cr(VI)-induced mitochondrial dysfunction in L02 hepatocytes, which may provide the new avenue for developing effective strategies to protect against Cr(VI)-induced hepatotoxicity.

miR-139 Controls Viability Of Ovarian Cancer Cells Through Apoptosis Induction And Exosome Shedding Inhibition By Targeting ATP7A

Background

Emerging proof suggests that microRNA (miRNA) malfunction is correlated to the generation and development of multiple malignancies. It has been proven that miRNA (miR)-139 represses a variety of malignancies. However, the understanding of its impact on ovarian cancer (OC) is insufficient. We aimed to investigate the expression and function of miR-139 in OC.

Methods

The expression of mir-139 was detected and recorded, and the relationship of mir-139 remaining OC cells was explored. At the same time, we studied the correlation between ATP7A and mir-139 by the luciferase reporter test, Western blot, and quantitative real-time reverse transcription PCR.

Results

The expression of miR-139 was remarkably downregulated in OC specimens. Furthermore, excessive miR-139 expression noticeably inhibited the migration, colony generation, proliferation, and invasion of OC cells. In addition, excessive miR-139 expression remarkably repressed the death and the expression of proteins related to cell death in OC cells, as well as inhibited the shedding of exosomes. According to the luciferase reporter test, Western blot, and quantitative real-time reverse transcription PCR, miR-139 directly targeted ATP7A. Furthermore, the expression of ATP7A was found to be negatively related to miR-139 levels in OC specimens. It was revealed via a rescue experiment that excessive ATP7A expression counteracted the repressive effect of miR-139 in OC cells.

Conclusion

It was revealed via an in vivo study that miR-139 remarkably inhibited the growth of malignancies by downregulating ATP7A in nude mice. miR-139 represses the development of malignancies in OC by directly targeting ATP7A, offering an innovative approach for molecular therapy of OC.

Expression of Clusterin suppresses Cr(VI)-induced premature senescence through activation of PI3K/AKT pathway

Our group found that long-term low-dose exposure to hexavalent chromium [Cr(VI)] in L-02 hepatocytes resulted in premature senescence, which accompanied by the increased expression of Clusterin (CLU), but the functional role of CLU in premature senescence has never been explored. In the present study, the CLU overexpressed or silenced L-02 hepatocytes were established by lentiviral vector transfection. Cell viability assay, cell cycle analysis, western blotting, plate clone formation assay, and confocal microcopy were performed. The results indicated that Cr(VI)-induced premature senescence was associated with phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) pathway inhibition, and high expression of CLU in the senescent cells exerted its functional role of promoting cell proliferation. CLU could complex with eukaryotic translation initiation factor 3 subunit I (EIF3I) and prevent its degradation, leading to the increase of AKT activity in Cr(VI)-exposed senescent hepatocytes. Blockage of the PI3K/AKT pathway with its inhibitor LY294002 eliminated the inhibitory effect of CLU on Cr(VI)-induced premature senescence. We concluded that high expression of CLU suppressed Cr(VI)-induced premature senescence through activation of PI3K/AKT pathway, which will provide the experimental basis for the study of Cr(VI)-induced liver cancer, especially for the elucidation of the mechanism of liver cancer cells escaping from senescence.

Synthesis of Acetamides from Aryl Amines and Acetonitrile by Diazotization under Metal-Free Conditions

An efficient and metal-free coupling reaction has been developed that affords acetamides from the corresponding aryl amines and acetonitrile. This method tolerates a wide range of functional groups and is selective toward aryl amines. Preliminary mechanistic studies were conducted.

[Pharmacokinetics of skin and blood of Tripterygium wilfordii and Paeonia lactiflora micro-emulsion gel based on micro-dialysis technology]

To further investigate the metabolism of Tripterygium wilfordii and Paeonia lactiflora micro-emulsion gel in vivo,an LCMS/MS method was established for the determination of triptolide and paeoniflorin in T. wilfordii and P. lactiflora micro-emulsion gel.The extracorporeal recovery rate of blood probe was measured by concentration difference methods( incremental method and decremental method). Meanwhile,the skin and blood micro-dialysis methods of tripterine and paeoniflorin were established,and the pharmacokinetics of T. wilfordii microemulsion gel in skin and blood was studied by micro-dialysis combined with LC-MS/MS quantitative analysis. The results showed that the established method for the determination of triptolide and paeoniflorin in T. wilfordii microemulsion gel was well linear within the required range,and the specificity,recovery rate and degree of precision of the chromatography all conformed to the research requirements of micro-dialysis samples. The stability of freeze-thawing and the residual effect all conformed to the criteria of biological sample methodology. The probe recovery rates measured by incremental method and decremental method were almost consistent with the extracorporeal recovery rate test. The recovery rates of paeoniflorin in skin and blood micro-dialysis were( 30. 60±1. 09) % and( 28. 01± 1. 75) %,respectively. And the recovery rates of skin and blood micro-dialysis were( 26. 79 ± 2. 78) % and( 25. 39±1. 86) %,respectively. The intraday recovery rate of probes was stable within 11 h. The results of pharmacokinetic study showed that the Cmaxvalues of triptolide in skin and blood were( 148. 03±41. 51) and( 76. 77±15. 27) μg·L-1,respectively. And the Tmaxvalues were( 2. 33±0. 29) and( 3. 00± 0) h,respectively. The AUC0-11 hvalues were( 2 814. 05± 1 070. 37) and( 1 580. 63±208. 27) μg·h·L-1,respectively. The MRT0-11 hvalues were( 4. 20± 0. 33) and( 4. 54± 0. 34) h,respectively. The T1/2 values were( 4. 61±4. 11) and( 1. 07± 0. 13) h,respectively. The Cmaxvalues of paeoniflorin in skin and blood were( 991. 88 ± 152. 22) and( 407. 02±120. 06) μg·L-1,respectively. The Tmaxvalues were( 2. 00±0) h and( 2. 83±0. 29) h,respectively. The AUC0-11 hvalues were( 18 430. 27±3 289. 35) and( 6 338. 59 ± 1 659. 32) μg·h·L-1,respectively. The MRT0-11 hvalues were( 4. 29 ± 0. 16) and( 4. 00±0. 05) h,respectively. The T1/2 values were( 2. 16±0. 43) and( 1. 78±0. 48) h,respectively. The results suggested that micro-emulsion gel played a role in forming skin reservoir through percutaneous penetration. It not only could improve drug transdermal efficiency,but also control the sustained release of drug and form a long-term effect.

Probing magnetic order and disorder in the one-dimensional molecular spin chains CuF2(pyz) and [Ln(hfac)3(boaDTDA)] n (Ln = Sm, La) using implanted muons

We present the results of muon-spin relaxation ([Formula: see text]SR) measurements on antiferromagnetic and ferromagnetic spin chains. In antiferromagnetic CuF₂(pyz) we identify a transition to long range magnetic order taking place at [Formula: see text] K, allowing us to estimate a ratio with the intrachain exchange of [Formula: see text] and the ratio of interchain to intrachain exchange coupling as [Formula: see text]. The ferromagnetic chain [Sm(hfac)₃(boaDTDA)] _n undergoes an ordering transition at [Formula: see text] K, seen via a broad freezing of dynamic fluctuations on the muon (microsecond) timescale and implying [Formula: see text]. The ordered radical moment continues to fluctuate on this timescale down to 0.3 K, while the Sm moments remain disordered. In contrast, the radical spins in [La(hfac)₃(boaDTDA)] _n remain magnetically disordered down to T  =  0.1 K suggesting [Formula: see text].

[Clinical features and prognosis of infective endocarditis patients with acute kidney injury]

OBJECTIVE

To investigate the clinical features and treatment of infective endocarditis (IE) patients with acute kidney injury (AKI), and to compare the adverse complications and outcome with IE patients without AKI.

METHODS

Clinical data of 100 IE cases in Peking University First Hospital from January 2002 to June 2018 were retrospectively reviewed. The patients were divided into AKI group (n=21) and non-AKI group (n=79) based on the AKI network (AKIN) definition. The clinical data and prognosis were compared between the two groups.

RESULTS

The incidence of AKI was 21%. The average age was (43.7±15.7) years, and the ratio of male to female was 3 ∶1. There was no significant difference in age and gender between the two groups. Compared with non-AKI group, the AKI group had more rash and lower limbs edema (P=0.017 and P=0.001), higher urine blood and protein positive rate (both P<0.001). Lower hemoglobin and serum albumin level (both P<0.001), worse clinical cardiac function (NYHA III-IV, P=0.033) were found in AKI group compared with non-AKI group. There was no significant difference in microbiologic positive rate and pathogenic bacteria sorts between the two groups. Nine patients refused surgery, and the other 91 cases underwent cardiac surgery with cardiopulmonary bypass under general anesthesia, including 19 cases of AKI group and 72 cases of non-AKI group. The ventilation time and intensive care unit (ICU) stay time were longer in AKI group than in non-AKI group (P=0.028 and P=0.003). AKI group needed more red blood cell transfusion (P=0.010). Using the last serum creatinine before surgery as basic level, there was more new-onset AKI cases in AKI group than in non-AKI group. During the median follow-up time 42 months, there was no significant difference in perioperative and follow-up mortality between the two groups (P=0.463 and P=0.581).

CONCLUSION

More perioperation complications occurred in IE patients with AKI, but no significant difference in in-hospital and follow-up mortality between the AKI and non-AKI groups was observed.

Investigation of physicochemical composition and microbial communities in traditionally fermented vrum from Inner Mongolia

Mongolian traditionally fermented vrum is known for its functional characteristics, and indigenous microbial flora plays a critical role in its natural fermentation. However, studies of traditionally fermented vrum are still rare. In this study, we investigated the artisanal production of traditionally fermented vrum from Inner Mongolia. In general, its physicochemical composition was characterized by 34.5 ± 8% moisture, 44.9 ± 12.1% fat, 10.6 ± 3.2% protein, and 210 ± 102°T. The total lactic acid bacteria and yeast counts ranged from 50 to 2.8 × 10⁸ cfu/g and from 0 to 1.1 × 10⁶ cfu/g, respectively. We studied bacterial and fungal community structures in 9 fermented vrum; we identified 5 bacterial phyla represented by 11 genera (an average relative abundance >1%) and 8 species (>1%), and 3 fungal phyla represented by 8 genera (>1%) and 8 species (>1%). Relative abundance values showed that Lactococcus and Lactobacillus were the most common bacterial genera, and Dipodascus was the predominant fungal genus. This scientific investigation of the nutritional components, microbial counts, and community profiles in Mongolian traditionally fermented vrum could help to develop future functional biomaterials and probiotics.

The Epidemic Genotypes of Human Adenovirus in Outpatient Children with Adenoviral Conjunctivitis from 2011 to 2012 in Jiangxi, China

BACKGROUND

Human adenoviruses (HAdV) are a common cause of viral conjunctivitis, making surveillance of them from sporadic cases of conjunctivitis important.

METHODS

To acquire a better understanding of the epidemic genotypes of HAdV in outpatient children with adenoviral conjunctivitis in Jiangxi Province, China (2011-2012), 179 samples from cases with a high suspicion of HAdV were analyzed by PCR. Samples confirmed to be HAdV-positive by PCR were cultured in Hep-2 cells to isolate the viruses, which were then identified through hexon gene sequencing.

RESULTS

The adenoviral conjunctivitis positivity rate was 74.86% (134/179), from which 71.64% (96/134) were infections in boys, and 92.54% (124/134) were infections in children under 5 years of age. Sixty-nine HAdV strains were isolated from the positive samples and 69 sequences were obtained. Phylogenetic analysis indicated that 33 strains (47.82%) clustered with HAdV-B7, 21 (30.43%) with HAdV-B3, 6 (8.70%) with HAdV-B55, 6 (8.70%) with HAdV-E4, 1 with HAdV-B21 (1.45%), 1 with HAdV-D37 (1.45%), and 1 with HAdV-D64 (1.45%).

CONCLUSIONS

This is the first identification of HAdV-B55 relating to adenoviral conjunctivitis in China. These findings provide a firm basis for future surveillance of adenoviral conjunctivitis in China or other East Asian regions.

Proteomics analysis reveals heat shock proteins involved in caprine parainfluenza virus type 3 infection

BACKGROUND

Caprine parainfluenza virus type 3 (CPIV3) is major pathogen of goat herds causing serious respiratory tract disease and economic losses to the goat industry in China. We analyzed the differential proteomics of CPIV3-infected Madin-Darby bovine kidney (MDBK) cells using quantitative iTRAQ coupled LC-MS/MS. In addition, four DEPs were validated by qRT-PCR and western blot analysis.

RESULTS

Quantitative proteomics analysis revealed 163 differentially expressed proteins (DEPs) between CPIV3-infected and mock-infected groups (p-value < 0.05 and fold change > 1.2), among which 91 were down-regulated and 72 were up-regulated. Gene ontology (GO) analysis showed that these DEPs were involved in molecular functions, cellular components and biological processes. Biological functions in which the DEPs were involved in included diseases, genetic information processing, metabolism, environmental information processing, cellular processes, and organismal systems. STRING analysis revealed that four heat shock proteins (HSPs) included HSPA5, HSPA1B, HSP90B1 and HSPA6 may be associated with proliferation of CPIV3 in MDBK cells. qRT-PCR and western blot analysis showed that the selected HSPs were identical to the quantitative proteomics data.

CONCLUSION

To our knowledge, this is the first report of the proteomic changes in MDBK cells after CPIV3 infection.

Phenotypic analysis of atopic dermatitis in children aged 1-12 months: elaboration of novel diagnostic criteria for infants in China and estimation of prevalence

BACKGROUND

Atopic dermatitis (AD) is the most common skin disorder in infancy. However, the diagnosis and definite significance of infantile AD remains a debated issue.

OBJECTIVE

To analyse the phenotypes of AD in infancy, to establish diagnostic criteria and to estimate the prevalence of this condition in China.

METHODS

This is a multicentric study, in which 12 locations were chosen from different metropolitan areas of China. Following careful and complete history-taking and skin examination, the definite diagnosis of AD was made and the severity based on the SCORAD index was determined by local experienced dermatologists. Based on the detailed phenotyping, the major and representative clinical features of infantile AD were selected to establish the diagnostic criteria and evaluate their diagnostic efficacy.

RESULTS

A total of 5967 infants were included in this study. The overall point prevalence of AD was 30.48%. The infantile AD developed as early as at the second month of life, and its incidence peaked in the third month of life at 40.81%. The proportion of mild, moderate and severe AD was 67.40%, 30.57% and 2.03%, respectively. The most commonly seen manifestations in the infantile AD were facial dermatitis (72.07%), xerosis (42.72%) and scalp dermatitis (27.93%). We established the novel diagnostic criteria of infants, which included: (i) onset after 2 weeks of birth; (ii) pruritus and/or irritability and sleeplessness comparable with lesions; and (iii) all two items above with one of the following items can reach a diagnosis of AD: (i) eczematous lesions distributed on cheeks and/or scalp and/or extensor limbs, and (ii) eczematous lesions on any other parts of body accompanied by xerosis.

CONCLUSIONS

In China, the prevalence of AD in infancy is 30.48% according to clinical diagnosis of dermatologists. The novel Chinese diagnostic criteria for AD in infants show a higher sensitivity and comparable specificity.

Radical and testis-sparing surgery for primary testicular tumors: A single-center experience

The aim of the present study was to assess the oncological and functional outcomes of testis-sparing surgery (TSS) for testicular tumors compared with radical orchiectomy (RO) in a single center. A retrospective comparative cohort study was conducted in Changzheng Hospital. Patients were identified using the hospital information system from January 1999 to December 2016, collecting all of the data regarding clinical, treatment and prognostic profiles. Patient follow-up was also executed to obtain information on patients' survival status, serum markers profiles, disease progression, androgen substitution requirement and paternity status. In total 158 patients were enrolled into the cohort study, including 23 TSS cases. The TSS procedure was primarily conducted in younger patients (average age, 31.9 vs. 47.7 years) or those with smaller tumors (average tumor diameter, 26.0 vs. 51.5 mm). The overall survival and recurrence free survival revealed no differences in the two groups, suggesting similar oncological outcomes. Kaplan-Maier analysis demonstrated a higher cumulative paternity rate in the TSS group than in RO group, indicating a possible advantage of preserving patients' fertility in TSS over RO. TSS with proper adjuvant therapies proved to be a promising alternative in the avoidance of emasculation, infertility, life-long androgen substitution and other psychosexual difficulties, as the oncological outcomes were not inferior to RO in the selected cases. However, further investigation is required in order to assess its oncological and functional values.

P30 A PRISMA systematic review and meta-analysis of open and novel ‘minimally invasive’ techniques for mesial temporal lobe epilepsy (MTLE)

Objectives

One third of patients with focal epilepsy fail to achieve seizure freedom despite best medical therapy. Surgery may provide seizure freedom if the epileptogenic zone can be safely remove. We compare the outcomes following open surgery, laser interstitial thermal therapy (LITT), radiofrequency ablation (RFA) and radiosurgery (RS).

Design

PRISMA systematic review and meta-analysis.

Subjects

MTLE

Methods

Structured searchs of PubMed, Embase and Cochrane databases. Random effects meta-analysis to calculate effects sizes and a pooled estimate of the probability of remaining seizure free at one year following intervention.

Results

From 1212 screened publications, 57 articles were included in the quantitative analysis. Open surgery included anterior temporal lobectomy as well as transcortical, subtemporal and transsylvian selective amygdalohippocampectomy. The probability of remaining seizure free at one year was 0.89 (95% CI 0.83–0.93) with open surgery based on Level 1 and 2 evidence. RS resulted in 0.88 (95% CI 0.84–0.90) probability and a single RCT revealed RS was less efficacious than open surgery. Follow up duration and study sizes were limited with LITT and RFA providing a probability of remaining seizure free at one year of 0.71 (95% CI 0.65–0.76) and 0.86 (95% CI 0.76–0.92) respectively.

Conclusions

There is no evidence supporting novel ‘minimally invasive’ approaches as being as efficacious as open surgery. Secondary outcome measures such as neuropsychological outcome and intervention morbidity are poorly reported.

Reduction of T Cells and Hsa-miR150-5p in Female Canoeing Athletes: Preliminary Evidence Between Exercise Training and Immune

Xiao, F, Yang, Y, Xiao, L, Xia, Z, Wang, L, Yang, K, and Wang, S. Reduction of T cells and hsa-miR150-5p in female canoeing athletes: Preliminary evidence between exercise training and immune. J Strength Cond Res XX(X): 000-000, 2018-This article aims to reveal the alteration of immune profile in teenage canoeing athletes, by which applies a clue for regulation of exercise on human immune. Thirty-one teenagers of female canoeing athletes and age-matched subjects participated in this research. Peripheral leukocytes' microRNAs (miRNAs) were analyzed using Agilent human microRNA 2.0 and gene software. The miRNA candidates were quantified by reverse transcription real-time quantitative polymerase chain reaction (RT-qPCR). The percentages of various lymphocytes were tested using flow cytometry. There were 6 miRNAs (hsa-miR150-5p, 31-5p, 3659, 4419a, 650, and 8485) lower in canoeing athletes, and the reduction of miR-150 was identified by RT-qPCR (p = 0.021). Canoeing athletes had lower percent of CD3 T cells than the subjects with no exercise training had (p < 0.001), but the ratio of CD4 to CD8 and the percent of CD4 T cells and CD8 T cells showed no significant difference between these 2 groups. T cells and hsa-miR150-5p are sensitive to the long-time heavy exercise training, and the exercise for winning competition regulates the immune system by inhibiting T cells and hsa-miR150-5p.

An innovative reversed-phase monolithic column modified with 4-vinylbiphenyl and ionic liquid stationary phases for capillary electrochromatography

A poly(VBP-co-EDMA-co-IL) monolithic column was used for electrochromatographic separation.

Comparison of several commonly used detection indicators of cell senescence

Cell senescence is the state of irreversible growth arrest that can be triggered by a variety of different cellular stresses. Currently, the commonly used detection indicators involved in the study of cell senescence include senescence-associated β-galactosidase, Clusterin, Telomeres/Telomerase, senescence-associated heterochromatin foci, senescence-associated secretory phenotype, senescence marker protein-30, tumor suppressor genes p53 and p16, and other indicators such as Ki67 and decoy receptor 2. These indicators are widely used in the study of cell senescence, each with its own characteristics, advantages, and disadvantages. This review summarizes several commonly used cell senescence indicators and compares their accuracy, credibility, specificity, and the scope of their potential application.

Graphene Family Nanomaterials: Properties and Potential Applications in Dentistry

Graphene family nanomaterials, with superior mechanical, chemical, and biological properties, have grabbed appreciable attention on the path of researches seeking new materials for future biomedical applications. Although potential applications of graphene had been highly reviewed in other fields of medicine, especially for their antibacterial properties and tissue regenerative capacities, in vivo and in vitro studies related to dentistry are very limited. Therefore, based on current knowledge and latest progress, this article aimed to present the recent achievements and provide a comprehensive literature review on potential applications of graphene that could be translated into clinical reality in dentistry.

Asymmetric Synthesis of Chiral Flavan-3-Ols

Flavan-3-ols are a series of natural products widely present in plants and show versatile biological activities. The structures of such compounds are characterized by owing two adjacent chiral centers and three rings. Their interesting structures and promising biological activities have driven increasing research developments toward the preparation of enantioenriched flavan-3-ols. This review summarizes the recent approaches for the asymmetric synthesis of chiral flavan-3-ols from two strategies in the construction of chiral centers. The key steps in the synthetic protocol involve Sharpless asymmetric dihydroxylation, Shi asymmetric epoxidation and Sharpless asymmetric epoxidation.

Cr(VI)-Induced Autophagy Protects L-02 Hepatocytes from Apoptosis Through the ROS-AKT-mTOR Pathway

BACKGROUND/AIMS

Hexavalent chromium [Cr(VI)] pollution has become a global concern for both ecosystems and human health. Our previous study revealed Cr(VI) could induce both apoptosis and autophagy in L-02 hepatocytes. Here, we sought to explore the underlying mechanism of Cr(VI)-induced autophagy and its exact role in cell death.

METHODS

Autophagy ultrastructure was observed under transmission electron microscope (TEM), autophagy flux was measured with double-tagged mCherry-green fluorescent protein (GFP)-microtubule-associated protein 1 light chain 3 (LC3) assay, long-lived protein degradation assay, and LC3II expression assay in the presence of lysosomal inhibitor, bafilomycin A1 (BafA1). Reactive oxygen species (ROS) level was determined using fluorescent probe dichloro-dihydrofluorescein diacetate (DCFH-DA). The expression levels of Beclin-1, LC3, p62/ SQSTM1, and AKT-mammalian target of rapamycin (mTOR) pathway-related molecules including phosphorylation (p)-AKT, AKT, p-mTOR, and mTOR were examined using real-time polymerase chain reaction (RT-PCR) and western blotting. Apoptosis was determined using Annexin V- fluorescein isothiocyanate (FITC)/propidium iodide (PI) staining.

RESULTS

Our results demonstrated Cr(VI) exposure activated autophagy in L-02 hepatocytes, as evidenced by the accumulation of autophagosomes, the increase of LC3-II and degradation of p62/ SQSTM1, and the enhanced overall degradation of proteins. We also confirmed Cr(VI)-induced LC3-II elevation mainly came from autophagy induction rather than lysosomal degradation impairment. ROS-AKT-mTOR pathway was associated with Cr(VI)-induced autophagy, and ROS scavenger N-acetylcysteine (NAC) pretreatment inhibited Cr(VI)-induced autophagy by alleviating the inhibition of the AKT-mTOR pathway. Autophagy inhibitors 3-methyladenine (3-MA) and chloroquine diphosphate (CDP) promoted Cr(VI)-induced apoptotic death.

CONCLUSION

These findings indicated Cr(VI)-induced autophagy protected L-02 hepatocytes from apoptosis through the ROS-AKT-mTOR pathway.

Role of mitochondrial damage in Cr(VI)‑induced endoplasmic reticulum stress in L‑02 hepatocytes

Although it is well reported that mitochondrial damage and endoplasmic reticulum (ER) stress (ERS) are involved in heavy metal‑induced cytotoxicity, the role of mitochondrial damage in hexavalent chromium [Cr(VI)]‑induced ERS and the correlation between the two have not been described and remain to be elucidated. The present study evaluated the ability of Cr(VI) to induce ERS in L‑02 hepatocytes, and subsequently examined the role of reactive oxygen species (ROS)‑mediated mitochondrial damage in Cr(VI)‑induced ERS. The findings demonstrated that Cr(VI) induced ERS, which was characterized by the upregulation of ERS‑associated genes and the substantial release of Ca2+ from the ER. The Cr(VI)‑induced mitochondrial production of ROS, by disturbing mitochondrial respiratory chain complexes I and II, may damage mitochondria directly by inducing mitochondrial permeability transition pore opening and mitochondrial membrane potential collapse. The results additionally demonstrated that Cr(VI) induced Ca2+ release from the ER through ROS/caveolin‑1/protein kinase B/inositol 1,4,5‑trisphosphate receptor signaling. The application of the ROS scavenger N‑acetyl‑cysteine confirmed the role of ROS in Cr(VI)‑mediated mitochondrial damage, ERS and apoptotic cell death. The data obtained demonstrated the role of mitochondrial damage in Cr(VI)‑induced ERS and provide novel insight into the elucidation of Cr(VI)‑induced cytotoxicity.