RESUMO
Perfluorooctane sulfonate (PFOS), an officially listed persistent organic pollutant, is a widely distributed perfluoroalkyl substance. Epidemiological studies have shown that PFOS is intimately linked to the occurrence of insulin resistance (IR). However, the detailed mechanism remains obscure. In previous studies, we found that mitochondrial calcium overload was concerned with hepatic IR induced by PFOS. In this study, we found that PFOS exposure noticeably raised lysosomal calcium in L-02 hepatocytes from 0.5â¯h. In the PFOS-cultured L-02 cells, inhibiting autophagy alleviated lysosomal calcium overload. Inhibition of mitochondrial calcium uptake aggravated the accumulation of lysosomal calcium, while inhibition of lysosomal calcium outflowing reversed PFOS-induced mitochondrial calcium overload and IR. Transient receptor potential mucolipin 1 (TRPML1), the calcium output channel of lysosomes, interacted with voltage-dependent anion channel 1 (VDAC1), the calcium intake channel of mitochondria, in the PFOS-cultured cells. Moreover, we found that ATP synthase F1 subunit beta (ATP5B) interacted with TRPML1 and VDAC1 in the L-02 cells and the liver of mice under PFOS exposure. Inhibiting ATP5B expression or restraining the ATP5B on the plasma membrane reduced the interplay between TRPML1 and VDAC1, reversed the mitochondrial calcium overload and deteriorated the lysosomal calcium accumulation in the PFOS-cultured cells. Our research unveils the molecular regulation of the calcium crosstalk between lysosomes and mitochondria, and explains PFOS-induced IR in the context of activated autophagy.
Assuntos
Ácidos Alcanossulfônicos , Autofagia , Cálcio , Fluorocarbonos , Resistência à Insulina , Fígado , Lisossomos , Mitocôndrias , ATPases Mitocondriais Próton-Translocadoras , Ácidos Alcanossulfônicos/toxicidade , Fluorocarbonos/toxicidade , Animais , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Autofagia/efeitos dos fármacos , Cálcio/metabolismo , Camundongos , ATPases Mitocondriais Próton-Translocadoras/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Masculino , Canal de Ânion 1 Dependente de Voltagem/metabolismo , Linhagem Celular , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Poluentes Ambientais/toxicidade , Canais de Cátion TRPM/metabolismo , Camundongos Endogâmicos C57BLRESUMO
The incidence of nonalcoholic steatohepatitis (NASH) is related with perfluorooctane sulfonate (PFOS), yet the mechanism remains ill-defined. Mounting evidence suggests that ferroptosis plays a crucial role in the initiation of NASH. In this study, we used mice and human hepatocytes L-02 to investigate the role of ferroptosis in PFOS-induced NASH and the effect and molecular mechanism of PFOS on liver ferroptosis. We found here that PFOS caused NASH in mice, and lipid accumulation and inflammatory response in the L-02 cells. PFOS induced hepatic ferroptosis in vivo and in vitro, as evidenced by the decrease in glutathione peroxidase 4 (GPX4), and the increases in cytosolic iron, acyl-CoA synthetase long-chain family member 4 (ACSL4) and lipid peroxidation. In the PFOS-treated cells, the increases in the inflammatory factors and lipid contents were reversed by ferroptosis inhibitor. PFOS-induced ferroptosis was relieved by autophagy inhibitor. The expression of mitochondrial calcium uniporter (MCU) was accelerated by PFOS, leading to subsequent mitochondrial calcium accumulation, and inhibiting autophagy reversed the increase in MCU. Inhibiting mitochondrial calcium reversed the variations in GPX4 and cytosolic iron, without influencing the change in ACSL4, induced by PFOS. MCU interacted with ACSL4 and the siRNA against MCU reversed the changes in ACSL4ï¼GPX4 and cytosolic iron systemically. This study put forward the involvement of hepatic ferroptosis in PFOS-induced NASH and identified MCU as the mediator of the autophagy-dependent ferroptosis.
Assuntos
Ácidos Alcanossulfônicos , Autofagia , Cálcio , Coenzima A Ligases , Ferroptose , Fluorocarbonos , Hepatopatia Gordurosa não Alcoólica , Ferroptose/efeitos dos fármacos , Fluorocarbonos/toxicidade , Animais , Ácidos Alcanossulfônicos/toxicidade , Camundongos , Hepatopatia Gordurosa não Alcoólica/induzido quimicamente , Hepatopatia Gordurosa não Alcoólica/patologia , Autofagia/efeitos dos fármacos , Coenzima A Ligases/metabolismo , Humanos , Cálcio/metabolismo , Canais de Cálcio/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Linhagem Celular , Hepatócitos/efeitos dos fármacosRESUMO
Perfluorooctane sulfonate (PFOS) is known as a persistent organic pollutant. A significant correlation between PFOS and liver ferroptosis has been unveiled, but the precise mechanism needs to be elucidated. In prior research, we found that PFOS treatment provoked mitochondrial iron overload. In this study, we observed a gradual increase in lysosomal iron in L-O2 cells after exposure to PFOS for 0.5-24â¯h. In PFOS-exposed L-O2 cells, suppressing autophagy relieved the lysosomal iron overload. Inhibiting transient receptor potential mucolipin 1 (TRPML1), a calcium efflux channel on the lysosomal membrane, led to a further rise in lysosomal iron levels and decreased mitochondrial iron overload during PFOS treatment. Suppressing VDAC1, a subtype of voltage-dependent anion-selective channels (VDACs) on the outer mitochondrial membrane, had no impact on PFOS-triggered mitochondrial iron overload, whereas restraining VDAC2/3 relieved this condition. Although silencing VDAC2 relieved PFOS-induced mitochondrial iron overload, it had no effect on PFOS-triggered lysosomal iron overload. Silencing VDAC3 alleviated PFOS-mediated mitochondrial iron overload and led to an additional increase in lysosomal iron. Therefore, we regarded VDAC3 as the specific VDACs subtype that mediated the lysosomes-mitochondria iron transfer. Additionally, in the presence of PFOS, an enhanced association between TRPML1 and VDAC3 was found in mice liver tissue and L-O2 cells. Our research unveils a novel regulatory mechanism of autophagy on the iron homeostasis and the effect of TRPML1-VDAC3 interaction on lysosomes-mitochondria iron transfer, giving an explanation of PFOS-induced ferroptosis and shedding some light on the role of classic calcium channels in iron transmission.
RESUMO
As a well-known traditional Chinese medicine and functional food, Schisandra chinensis (S. chinensis) has been proved to possess excellent neuroprotective effects, and particularly the role of the polysaccharide fraction in neuroprotection has been increasingly emphasized. The aim of this study was to investigate the therapeutic effects and potential mechanism of action of the homogeneous polysaccharide SCP2, isolated and purified from S. chinensis polysaccharide (SCP), on Alzheimer's disease (AD) rats based on a holistic metabolomics approach in serum and urine. The results of the pharmacodynamics study showed that SCP2 significantly improved Aß25-35-induced cognitive dysfunction, improved oxidative damage and reduced Aß deposition in the hippocampus. The holistic metabolomics results of serum and urine showed that the intervention with SCP2 significantly reversed the metabolic profile disorder in AD rats. A total of 40 metabolites (21 serum metabolites and 19 urine metabolites) were identified, which were mainly involved in linoleic acid metabolism, alpha-linolenic acid metabolism and arachidonic acid metabolism. The results obtained in this study will provide new insights into the mechanisms of SCP2 in the treatment of AD and provide a basis for the subsequent structure-activity studies of SCP2.
Assuntos
Doença de Alzheimer , Medicamentos de Ervas Chinesas , Schisandra , Animais , Ratos , Doença de Alzheimer/tratamento farmacológico , Cromatografia Líquida de Alta Pressão , Medicamentos de Ervas Chinesas/uso terapêutico , Metabolômica , Polissacarídeos/farmacologia , Ratos Sprague-Dawley , Espectrometria de MassasRESUMO
Schisandra chinensis (S. chinensis) is an herbal medicine used for the treatment of Alzheimer's disease (AD). The purified polysaccharide fraction, namely SCP2, was previously isolated from S. chinensis crude polysaccharide (SCP) and its structure and in vitro activity were investigated. However, the in vivo activity of SCP2 and its potential mechanism for the treatment of AD have yet to be determined. This study used a combination of microbiomics and metabolomics to comprehensively explore the microbiota and metabolic changes in AD rats under SCP2 intervention, with the aim of elucidating the potential mechanisms of SCP2 in the treatment of AD. SCP2 showed significant therapeutic effects in AD rats, as evidenced by improved learning and memory capacity, reduced neuroinflammation, and restoration of the integrity of the intestinal barrier. Fecal metabolomic and microbiomic analyses revealed that SCP2 significantly modulated 19 endogenous metabolites and reversed gut microbiota disorders in AD rats. Moreover, SCP2 significantly increased the content of short-chain fatty acid (SCFAs) in the AD rats. Correlation analysis showed a significant correlation between gut microbes, metabolites and the content of SCFAs. Collectively, these findings will provide the basis for further development of SCP2.