On the mechanism underlying ethanol-induced mitochondrial dynamic disruption and autophagy response

Mitochondrial structure and function: a new direction for the targeted treatment of chronic liver disease with Chinese herbal medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Excessive fat accumulation, biological clock dysregulation , viral infections, and sustained inflammatory responses can lead to liver inflammation, fibrosis, and cancer, thus promoting the development of chronic liver disease. A comprehensive understanding of the etiological factors leading to chronic liver disease and the intrinsic mechanisms influencing its onset and progression can aid in identifying potential targets for targeted therapy. Mitochondria, as key organelles that maintain the metabolic homeostasis of the liver, provide an important foundation for exploring therapeutic targets for chronic liver disease. Recent studies have shown that active ingredients in herbal medicines and their natural products can modulate chronic liver disease by influencing the structure and function of mitochondria. Therefore, studying how Chinese herbs target mitochondrial structure and function to treat chronic liver diseases is of great significance.

AIM OF THE STUDY

Investigating the prospects of herbal medicine the Lens of chronic liver disease based on mitochondrial structure and function.

MATERIALS AND METHODS

A computerized search of PubMed was conducted using the keywords "mitochondrial structure", "mitochondrial function", "mitochondria and chronic liver disease", "botanicals, mitochondria and chronic liver disease".Data from the Web of Science and Science Direct databases were also included. The research findings regarding herbal medicines targeting mitochondrial structure and function for the treatment of chronic liver disease are summarized.

RESULTS

A computerized search of PubMed using the keywords "mitochondrial structure", "mitochondrial function", "mitochondria and chronic liver disease", "phytopharmaceuticals, mitochondria, and chronic liver disease", as well as the Web of Science and Science Direct databases was conducted to summarize information on studies of mitochondrial structure- and function-based Chinese herbal medicines for the treatment of chronic liver disease and to suggest that the effects of herbal medicines on mitochondrial division and fusion.The study suggested that there is much room for research on the influence of Chinese herbs on mitochondrial division and fusion.

CONCLUSIONS

Targeting mitochondrial structure and function is crucial for herbal medicine to combat chronic liver disease.

Probiotics as Potential Therapeutic Agents: Safeguarding Skeletal Muscle against Alcohol-Induced Damage through the Gut-Liver-Muscle Axis

Probiotics have shown the potential to counteract the loss of muscle mass, reduce physical fatigue, and mitigate inflammatory response following intense exercise, although the mechanisms by which they work are not very clear. The objective of this review is to describe the main harmful effects of alcohol on skeletal muscle and to provide important strategies based on the use of probiotics. The excessive consumption of alcohol is a worldwide problem and has been shown to be crucial in the progression of alcoholic liver disease (ALD), for which, to date, the only therapy available is lifestyle modification, including cessation of drinking. In ALD, alcohol contributes significantly to the loss of skeletal muscle, and also to changes in the intestinal microbiota, which are the basis for a series of problems related to the onset of sarcopenia. Some of the main effects of alcohol on the skeletal muscle are described in this review, with particular emphasis on the "gut-liver-muscle axis", which seems to be the primary cause of a series of muscle dysfunctions related to the onset of ALD. The modulation of the intestinal microbiota through probiotics utilization has appeared to be crucial in mitigating the muscle damage induced by the high amounts of alcohol consumed.

Body Composition in Chronic Liver Disease

Body composition has recently been attracting people's attention, not only from a cosmetic standpoint but also from the perspective of health and longevity. The body is classified into three components: fat, bone, and lean soft tissue, and it is common to see an increase in body fat and a decrease in total body muscle mass with aging. Aging-related loss of muscle mass and muscle function is referred to as primary sarcopenia, while sarcopenia caused by disease-specific conditions is referred to as secondary sarcopenia. On the other hand, the liver-muscle axis has been attracting attention in recent years, and it has become clear that the liver and the skeletal muscles interact with each other. In particular, patients with cirrhosis are prone to secondary sarcopenia due to protein-energy malnutrition, which is a characteristic pathophysiology of the disease, suggesting the importance of the organ-organ network. In this review, we would like to outline the latest findings in this field, with a focus on body composition in liver diseases such as liver cirrhosis, fatty liver disease, alcoholic liver disease, and hepatocellular carcinoma.

Val-Leu-Leu-Tyr (VLLY) Alleviates Ethanol-Induced Gastric Mucosal Cell Impairment by Improving Mitochondrial Fission

Ethanolic gastric mucosal impairment is one of the most common disorders in the gastrointestinal system. In this study, we investigated the potential alleviating effects of sea cucumber peptides on Ges-1 impairment caused by ethanol and the associated mechanisms. The sea cucumber peptide VLLY could promote the proliferation and migration of healthy Ges-1 cells. After ethanol injury, VLLY peptide treatment could greatly promote the migration of Ges-1 cells, scavenge intracellular and mitochondrial ROS, reverse mitochondrial fission and F-actin depolymerization, and improve mitochondrial respiration. VLLY peptide restored mitochondrial dynamics by downregulating Drp1 and Fis1 and upregulating Mfn2 against excessive mitochondrial fission. In addition, the VLLY peptide maintained the mitochondrial membrane potential, ablated the leakage of cytochrome c to the cytoplasm, upregulated the expression of the antiapoptotic factor Bcl-XL, decreased the expression of the proapoptotic factors of Bax, BAD, and cleaved caspase-3, and finally blocked the mitochondria-related apoptotic pathway. These findings strongly suggested that sea cucumber peptides could promote proliferation and migration of healthy Ges-1 cells and reverse ethanol-induced excess mitochondrial fission and maintain mitochondrial homeostasis through the Fis1/Bax pathway, thereby improving ethanol-induced apoptosis. VLLY offers a new perspective for improving the ethanolic gastric mucosal epithelial cell injury.

Ameliorative effect of diazepam against ethanol-induced mitochondrial disruption in brains of the mice

Brain oxidative damage and neurodegeneration by ethanol (ETH) are considered as important factors that triggered by oxidative stress. Recently, the abuse of diazepam (DZM) has increased by alcoholism-addicted patients. The present study evaluated the effects of combination treatment of ETH with DZM on oxidative damage induced in brain mitochondria of the mice. Only ETH (0.3, 0.6, and 2.5 g / kg) and ETH+ DZM (2.5 mg / kg) were administered intraperitoneally (ip) to the mice. Pathological changes and oxidative stress biomarkers including ROS, lipid peroxidation, carbonyl protein, mitochondrial function, and glutathione content were evaluated in brain mitochondria after 42 days. Results indicated that co-treatment of DZM and ETH significantly reduced mitochondrial toxicity, oxidative damage, pathological changes and increased level of glutathione. Subchronic ETH administration induced brain oxidative damage, mitochondrial disruption, and serious damage to the brain cells. Whereas, combination treatment improved oxidative damage, mitochondrial function, and pathological changes in brain cells after intoxication by ETH. These findings suggest antioxidant effect of DZM in combination with ETH and can be considered in reducing oxidative stress and mitochondrial damage attenuation in the brain. Combination therapy may be a better therapeutic candidate for prevention of brain oxidative damage induced by ETH.

Regular exercise attenuates alcoholic myopathy in zebrafish by modulating mitochondrial homeostasis

Alcoholic myopathy is caused by chronic consumption of alcohol (ethanol) and is characterized by weakness and atrophy of skeletal muscle. Regular exercise is one of the important ways to prevent or alleviate skeletal muscle myopathy. However, the beneficial effects and the exact mechanisms underlying regular exercise on alcohol myopathy remain unclear. In this study, a model of alcoholic myopathy was established using zebrafish soaked in 0.5% ethanol. Additionally, these zebrafish were intervened to swim for 8 weeks at an exercise intensity of 30% of the absolute critical swimming speed (Ucrit), aiming to explore the beneficial effects and underlying mechanisms of regular exercise on alcoholic myopathy. This study found that regular exercise inhibited protein degradation, improved locomotion ability, and increased muscle fiber cross-sectional area (CSA) in ethanol-treated zebrafish. In addition, regular exercise increases the functional activity of mitochondrial respiratory chain (MRC) complexes and upregulates the expression levels of MRC complexes. Regular exercise can also improve oxidative stress and mitochondrial dynamics in zebrafish skeletal muscle induced by ethanol. Additionally, regular exercise can activate mitochondrial biogenesis and inhibit mitochondrial unfolded protein response (UPRmt). Together, our results suggest regular exercise is an effective intervention strategy to improve mitochondrial homeostasis to attenuate alcoholic myopathy.

Click chemistry-based thiol redox proteomics reveals significant cysteine reduction induced by chronic ethanol consumption

In the U.S., alcohol-associated liver disease (ALD) impacts millions of people and is a major healthcare burden. While the pathology of ALD is unmistakable, the molecular mechanisms underlying ethanol hepatotoxicity are not fully understood. Hepatic ethanol metabolism is intimately linked with alterations in extracellular and intracellular metabolic processes, specifically oxidation/reduction reactions. The xenobiotic detoxification of ethanol leads to significant disruptions in glycolysis, β-oxidation, and the TCA cycle, as well as oxidative stress. Perturbation of these regulatory networks impacts the redox status of critical regulatory protein thiols throughout the cell. Integrating these key concepts, our goal was to apply a cutting-edge approach toward understanding mechanisms of ethanol metabolism in disrupting hepatic thiol redox signaling. Utilizing a chronic murine model of ALD, we applied a cysteine targeted click chemistry enrichment coupled with quantitative nano HPLC-MS/MS to assess the thiol redox proteome. Our strategy reveals that ethanol metabolism largely reduces the cysteine proteome, with 593 cysteine residues significantly reduced and 8 significantly oxidized cysteines. Ingenuity Pathway Analysis demonstrates that ethanol metabolism reduces specific cysteines throughout ethanol metabolism (Adh1, Cat, Aldh2), antioxidant pathways (Prx1, Mgst1, Gsr), as well as many other biochemical pathways. Interestingly, a sequence motif analysis of reduced cysteines showed a correlation for hydrophilic, charged amino acids lysine or glutamic acid nearby. Further research is needed to determine how a reduced cysteine proteome impacts individual protein activity across these protein targets and pathways. Additionally, understanding how a complex array of cysteine-targeted post-translational modifications (e.g., S-NO, S-GSH, S-OH) are integrated to regulate redox signaling and control throughout the cell is key to the development of redox-centric therapeutic agents targeted to ameliorate the progression of ALD.

A bifunctional hepatocyte-mitochondrion targeting nanosystem for effective astaxanthin delivery to the liver

A bifunctional hepatocyte-mitochondrion targeting nanosystem was prepared for astaxanthin by conjugating lactobionic acid (LA) and triphenylphosphonium-modified 2-hydroxypropyl-β-cyclodextrin onto sodium alginate. Hepatocyte-targeting evaluation indicated that the fluorescence intensity of HepaRG cells treated with the bifunctional nanosystem increased 90.3%, which was greater than that (38.7%) of the LA-only targeted nanosystem. The Rcoloc was 0.81 for the bifunctional nanosystem in mitochondrion-targeting analysis, which was greater than that (0.62) of the LA-only targeted nanosystem. The reactive oxygen species (ROS) level of the astaxanthin bifunctional nanosystem treated group significantly reduced to 62.20%, lower than that of free astaxanthin (84.01%) and LA-only targeted group (73.83%). Mitochondrial membrane potential recovered 97.35% in the astaxanthin bifunctional nanosystem treated group while the LA-only targeted group recovered 77.45%. The accumulation of bifunctional nanosystem in liver increased by 31.01% compared to the control. These findings indicated that the bifunctional nanosystem was beneficial for astaxanthin delivery in the liver precision nutrition intervention.

[Effect of erastin and G3139 on rat liver mitochondria in chronic alcoholic intoxication]

The effect of modulators of VDAC channels - G3139 and erastin on the mitochondrial permeability transition pore (mPTP) functioning and changes in the content of proteins involved in regulation of mPTP (VDAC, CNPase, and TSPO) has been investigated in liver mitochondria of rats with chronic alcohol intoxication. It was shown that the mitochondria of rats treated with ethanol were more sensitive to mPTP induction. Moreover, ethanol induced changes in the expression of mPTP regulator proteins. G3139 and erastin were also able to influence the studied mitochondrial parameters, and they increased their effect in the liver mitochondria of rats treated with ethanol, as compared to the mitochondria of control rats. We hypothesize that the results of this study may help to elucidate the mechanisms of chronic action of ethanol on mitochondria and contribute to the development of new therapeutic strategies for treating the consequences of ethanol-related diseases.

Rescue of Mitochondrial Function in Hutchinson-Gilford Progeria Syndrome by the Pharmacological Modulation of Exportin CRM1

Hutchinson-Gilford progeria syndrome (HGPS) is a rare premature aging disorder caused by the expression of progerin, a mutant variant of Lamin A. Recently, HGPS studies have gained relevance because unraveling its underlying mechanism would help to understand physiological aging. We previously reported that the CRM1-mediated nuclear protein export pathway is exacerbated in HGPS cells, provoking the mislocalization of numerous protein targets of CRM1. We showed that normalization of this mechanism by pharmacologically inhibiting CRM1 with LMB (specific CRM1 inhibitor), mitigates the senescent phenotype of HGPS cells. Since mitochondrial dysfunction is a hallmark of HGPS, in this study we analyze the effect of LMB on mitochondrial function. Remarkably, LMB treatment induced the recovery of mitochondrial function in HGPS cells, as shown by the improvement in mitochondrial morphology, mitochondrial membrane potential, and ATP levels, which consequently impeded the accumulation of ROS but not mitochondrial superoxide. We provide evidence that the beneficial effect of LMB is mechanistically based on a combinatory effect on mitochondrial biogenesis via upregulation of PGC-1α expression (master transcription cofactor of mitochondrial genes), and mitophagy through the recovery of lysosomal content. The use of exportin CRM1 inhibitors constitutes a promising strategy to treat HGPS and other diseases characterized by mitochondrial impairment.

Chronic Intermittent Ethanol Exposure Alters Behavioral Flexibility in Aged Rats Compared to Adult Rats and Modifies Protein and Protein Pathways Related to Alzheimer's Disease

Repeated excessive alcohol consumption increases the risk of developing cognitive decline and dementia. Hazardous drinking among older adults further increases such vulnerabilities. To investigate whether alcohol induces cognitive deficits in older adults, we performed a chronic intermittent ethanol exposure paradigm (ethanol or water gavage every other day 10 times) in 8-week-old young adult and 70-week-old aged rats. While spatial memory retrieval ascertained by probe trials in the Morris water maze was not significantly different between ethanol-treated and water-treated rats in both age groups after the fifth and tenth gavages, behavioral flexibility was impaired in ethanol-treated rats compared to water-treated rats in the aged group but not in the young adult group. We then examined ethanol-treatment-associated hippocampal proteomic and phosphoproteomic differences distinct in the aged rats. We identified several ethanol-treatment-related proteins, including the upregulations of the Prkcd protein level, several of its phosphosites, and its kinase activity and downregulation in the Camk2a protein level. Our bioinformatic analysis revealed notable changes in pathways involved in neurotransmission regulation, synaptic plasticity, neuronal apoptosis, and insulin receptor signaling. In conclusion, our behavioral and proteomic results identified several candidate proteins and pathways potentially associated with alcohol-induced cognitive decline in aged adults.

Alcohol as a Non-UV Social-Environmental Risk Factor for Melanoma

Although cancer mortality has declined among the general population, the incidence of melanoma continues to rise. While identifying high-risk cohorts with genetic risk factors improves public health initiatives and clinical care management, recognizing modifiable risk factors such as social-environmental risk factors would also affect the methods of patient outreach and education. One major modifiable social-environmental risk factor associated with melanoma is ultraviolet (UV) radiation. However, not all forms of melanoma are correlated with sun exposure or occur in sun-exposed areas. Additionally, UV exposure is rarely associated with tumor progression. Another social-environmental factor, pregnancy, does not explain the sharply increased incidence of melanoma. Recent studies have demonstrated that alcohol consumption is positively linked with an increased risk of cancers, including melanoma. This perspective review paper summarizes epidemiological data correlating melanoma incidence with alcohol consumption, describes the biochemical mechanisms of ethanol metabolism, and discusses how ethanol and ethanol metabolites contribute to human cancer, including melanoma.

Effects of Elamipretide on Autophagy in Renal Cells of Pigs with Metabolic Syndrome

Autophagy eliminates excessive nutrients and maintains homeostasis. Obesity and metabolic syndrome (MetS) dysregulate autophagy, possibly partly due to mitochondria injury and inflammation. Elamipretide (ELAM) improves mitochondrial function. We hypothesized that MetS blunts kidney autophagy, which ELAM would restore. Domestic pigs were fed a control or MetS-inducing diet for 16 weeks. During the 4 last weeks, MetS pigs received subcutaneous injections of ELAM (0.1 mg/kg/day, MetS + ELAM) or vehicle (MetS), and kidneys were then harvested to measure protein expression of autophagy mediators and apoptosis. Systemic and renal venous levels of inflammatory cytokines were measured to calculate renal release. The function of isolated mitochondria was assessed by oxidative stress, energy production, and pro-apoptotic activity. MetS slightly downregulated renal expression of autophagy mediators including p62, ATG5-12, mTOR, and AMPK vs. control. Increased mitochondrial H₂O₂ production accompanied decreased ATP production, elevated apoptosis, and renal fibrosis. In MetS + ELAM, mito-protection restored autophagic protein expression, improved mitochondrial energetics, and blunted renal cytokine release and fibrosis. In vitro, mitoprotection restored mitochondrial membrane potential and reduced oxidative stress in injured proximal tubular epithelial cells. Our study suggests that swine MetS mildly affects renal autophagy, possibly secondary to mitochondrial damage, and may contribute to kidney structural damage in MetS.

Polydatin attenuates chronic alcohol consumption-induced cardiomyopathy through a SIRT6-dependent mechanism

Polydatin has attracted much attention as a potential cardioprotective agent against ischemic heart disease and diabetic cardiomyopathy. However, the effect and mechanism of polydatin supplementation on alcoholic cardiomyopathy (ACM) are still unknown. This study aimed to determine the therapeutic effect of polydatin against ACM and to explore the molecular mechanisms with a focus on SIRT6-AMP-activated protein kinase (AMPK) signaling and mitochondrial function. The ACM model was established by feeding C57/BL6 mice with an ethanol Lieber-DeCarli diet for 12 weeks. The mice received polydatin (20 mg kg^-1) or vehicle treatment. We showed that polydatin treatment not only improved cardiac function but also reduced myocardial fibrosis and dynamin-related protein 1 (Drp-1)-mediated mitochondrial fission, and enhanced PTEN-induced putative kinase 1 (PINK1)-Parkin-dependent mitophagy in alcohol-treated myocardium. Importantly, these beneficial effects were mimicked by SIRT6 overexpression but abolished by the infection of recombinant serotype 9 adeno-associated virus (AAV9) carrying SIRT6-specific small hairpin RNA. Mechanistically, alcohol consumption induced a gradual decrease in the myocardial SIRT6 level, while polydatin effectively activated SIRT6-AMPK signaling and modulated mitochondrial dynamics and mitophagy, thus reducing oxidative stress damage and preserving mitochondrial function. In summary, these data present new information regarding the therapeutic actions of polydatin, suggesting that the activation of SIRT6 signaling may represent a new approach for tackling ACM-related cardiac dysfunction.

Oxidative Stress, Genomic Integrity, and Liver Diseases

Excess reactive oxygen species production and free radical formation can lead to oxidative stress that can damage cells, tissues, and organs. Cellular oxidative stress is defined as the imbalance between ROS production and antioxidants. This imbalance can lead to malfunction or structure modification of major cellular molecules such as lipids, proteins, and DNAs. During oxidative stress conditions, DNA and protein structure modifications can lead to various diseases. Various antioxidant-specific gene expression and signal transduction pathways are activated during oxidative stress to maintain homeostasis and to protect organs from oxidative injury and damage. The liver is more vulnerable to oxidative conditions than other organs. Antioxidants, antioxidant-specific enzymes, and the regulation of the antioxidant responsive element (ARE) genes can act against chronic oxidative stress in the liver. ARE-mediated genes can act as the target site for averting/preventing liver diseases caused by oxidative stress. Identification of these ARE genes as markers will enable the early detection of liver diseases caused by oxidative conditions and help develop new therapeutic interventions. This literature review is focused on antioxidant-specific gene expression upon oxidative stress, the factors responsible for hepatic oxidative stress, liver response to redox signaling, oxidative stress and redox signaling in various liver diseases, and future aspects.

Alcohol-Induced Neuroinflammatory Response and Mitochondrial Dysfunction on Aging and Alzheimer's Disease

Mitochondria are essential organelles central to various cellular functions such as energy production, metabolic pathways, signaling transduction, lipid biogenesis, and apoptosis. In the central nervous system, neurons depend on mitochondria for energy homeostasis to maintain optimal synaptic transmission and integrity. Deficiencies in mitochondrial function, including perturbations in energy homeostasis and mitochondrial dynamics, contribute to aging, and Alzheimer's disease. Chronic and heavy alcohol use is associated with accelerated brain aging, and increased risk for dementia, especially Alzheimer's disease. Furthermore, through neuroimmune responses, including pro-inflammatory cytokines, excessive alcohol use induces mitochondrial dysfunction. The direct and indirect alcohol-induced neuroimmune responses, including pro-inflammatory cytokines, are critical for the relationship between alcohol-induced mitochondrial dysfunction. In the brain, alcohol activates microglia and increases inflammatory mediators that can impair mitochondrial energy production, dynamics, and initiate cell death pathways. Also, alcohol-induced cytokines in the peripheral organs indirectly, but synergistically exacerbate alcohol's effects on brain function. This review will provide recent and advanced findings focusing on how alcohol alters the aging process and aggravates Alzheimer's disease with a focus on mitochondrial function. Finally, we will contextualize these findings to inform clinical and therapeutic approaches towards Alzheimer's disease.

Involvement of mitochondrial fission in renal tubular pyroptosis in mice exposed to high and environmental levels of glyphosate combined with hard water

Chronic interstitial nephritis in agricultural communities (CINAC) has reached epidemic proportions. The combination of glyphosate and hard water has been postulated to play a potent aetiological role in CINAC. Therefore, dynamin-related protein 1 (Drp1)-mediated aberrant mitochondrial fission and subsequent activation of the nucleotide-binding oligomerization domain (NOD)-like receptor protein 3 (Nlrp3)/caspase1 pathway may be involved in the pathogenesis of nephropathy. In the present study, mice were sub-chronically exposed to high doses and environmental levels of glyphosate (100 mg/kg body weight (mg/kg·bw) glyphosate in Roundup and 0.7 mg/L pure glyphosate, respectively) and hard water (2500 mg/L CaCO3 and 250 mg/L Ca2+, respectively) in drinking water. Moreover, Mdivi-1 (Md-1, 10 mg/kg·bw) was intraperitoneally injected to inhibit Drp1 on the basis of the high-dose experiment. Histopathological examination, biochemical analysis, ELISA, western blotting and fluorescent staining were used to analyse renal structure, renal tubular pyroptosis and mitochondrial fission/fusion alterations. The results showed dramatic proximal tubular injury, particularly in the combined groups. Moreover, significant increases in the protein expression levels of calmodulin (CaM), calmodulin-dependent protein kinase II (CaMKII), Drp1/p-Drp1-Ser616 and the Txnip/Nlrp3/caspase1 signalling pathway, and alterations in oxidative stress were observed in the combined groups, and these effects were attenuated by the Drp1 inhibitor Md-1. Intriguingly, there may be a synergistic effect of glyphosate and hard water on renal injury. Taken together, these results suggest that the combination of glyphosate and hard water, even at environmental exposure levels, enhances pyroptosis and ongoing tubulointerstitial inflammation through excessive Drp1-mediated mitochondrial fission.

Sarcopenia-The Impact on Physical Capacity of Liver Transplant Patients

Optimizing patients' condition before liver transplantation (LT) could potentially improve survival of LT patients. We focused on sarcopenia, as a common factor in liver transplant candidates that can impact their cardiopulmonary performance at the point of listing, morbidity, and mortality after LT. We performed a single-center cohort study on 98 consecutive patients with liver cirrhosis who were transplanted between March 2015 and December 2017. The third lumbar vertebra skeletal muscle index (L3SMI) was calculated using CT imaging to distinguish sarcopenia at listing for LT. Data regarding liver function, body mass index (BMI), cardiac biomarkers, the peak oxygen uptake (VO2) and LT outcome were collected and correlated to L3SMI. For data analysis the Dell Statistica (Version 13. Dell Inc., Rondrock, TX, USA) was used. In total, 98 cirrhotic patients were included. Fifty-five (56.1%) patients, mostly males, had sarcopenia according to L3SMI, with the lowest L3SMI in males with alcohol-related liver disease. Lower L3SMI correlated with lower BMI, lower VO2 peak, and higher NTproBNP (all p < 0.001) and revealed an essential correlation with prolonged ICU stay (r = -0.21, p < 0.05). 33 patients were unable to perform cardio-pulmonary exercise test, mostly sarcopenic (67%), with more advanced liver insufficiency (assessed with CPC and MELD scores) and longer stay at ICU after LT (all p < 0.001). Sarcopenia was common among LT recipients. It was associated with inferior result in cardio-pulmonary performance before LT and prolonged ICU stay after grafting.

Chronic Alcohol Intake Exacerbates Cardiac Dysfunction After Myocardial Infarction

AIMS

Alcohol intake is a risk factor for cardiovascular diseases. This study was designed to investigate whether chronic alcohol intake affects myocardial infarction (MI)-induced cardiac remodeling and heart failure.

METHODS

Eight-week-old male C57BL/6 mice were randomly divided into four groups: Sham group (Sham), MI plus drinking water group (MI + Vehicle), and MI plus daily alcohol intake for 6 weeks with or without gavage of additional alcohol every 3 days (MI + Alcohol and MI + Alcohol + G). The MI were induced by permanent left anterior descending (LAD) coronary artery ligation surgery before vehicle or alcohol treatment. The blood alcohol concentration (BAC), cardiac function, release of cardiac enzymes, pathological changes and mitochondrial function were measured.

RESULTS

As expected, supplementation of alcohol in drinking water significantly increased random BAC in mice. Long-term exposure to alcohol further reduced body weight, ejection fraction and fractional shortening in comparison with the MI + Vehicle group. Histopathological data showed that alcohol increased fibrosis in infarct zone, which was well correlated with the functional decline. Also, as compared to the MI + Vehicle group, the adenosine diphosphate-supported respiratory function of freshly isolated cardiac mitochondria was inhibited in the MI + Alcohol + G group. Besides, upon MI-induced cardiac damage, we did not observe further changes in heart weight, cardiomyocyte enlargement in remote zone, exercise capacity, lung edema and the release of cardiac enzyme after chronic alcohol intake.

CONCLUSIONS

Our study demonstrated that chronic daily alcohol exposure exacerbated MI-induced cardiac dysfunction, which is related to promoted myocardial fibrosis and inhibited mitochondrial function.

Sarcopenia in chronic liver disease: mechanisms and countermeasures

Sarcopenia, a condition of low muscle mass, quality, and strength, is commonly found in patients with cirrhosis and is associated with adverse clinical outcomes including reduction in quality of life, increased mortality, and posttransplant complications. In chronic liver disease (CLD), sarcopenia is most commonly defined through the measurement of the skeletal muscle index of the third lumbar spine. A major contributor to sarcopenia in CLD is the imbalance in muscle protein turnover, which likely occurs due to a decrease in muscle protein synthesis and an elevation in muscle protein breakdown. This imbalance is assumed to arise due to several factors including accelerated starvation, hyperammonemia, amino acid deprivation, chronic inflammation, excessive alcohol intake, and physical inactivity. In particular, hyperammonemia is a key mediator of the liver-gut axis and is known to contribute to mitochondrial dysfunction and an increase in myostatin expression. Currently, the use of nutritional interventions such as late-evening snacks, branched-chain amino acid supplementation, and physical activity have been proposed to help the management and treatment of sarcopenia. However, little evidence exists to comprehensively support their use in clinical settings. Several new pharmacological strategies, including myostatin inhibition and the nutraceutical Urolithin A, have recently been proposed to treat age-related sarcopenia and may also be of use in CLD. This review highlights the potential molecular mechanisms contributing to sarcopenia in CLD alongside a discussion of existing and potential new treatment strategies.

Chronic Alcohol Exposure Induces Aberrant Mitochondrial Morphology and Inhibits Respiratory Capacity in the Medial Prefrontal Cortex of Mice

Alcohol use disorder (AUD) is characterized as a chronic, relapsing disease with a pattern of excessive drinking despite negative consequences to an individual’s life. Severe chronic alcohol use impairs the function of the medial prefrontal cortex (mPFC), which contributes to alcohol-induced cognitive and executive dysfunction. The mPFC contains more mitochondria compared to other cortical areas, which suggests mitochondrial damage may occur in AUD and trigger subsequent behavior change. Here, we identified morphological and functional changes in mitochondria in the mPFC in C57BL6/J mice after 8 h of withdrawal from chronic intermittent alcohol (CIA) exposure. Three-dimensional serial block-face scanning electron microscopy (SBFSEM) reconstruction revealed that CIA exposure elongated mPFC mitochondria and formed mitochondria-on-a-string (MOAS). Furthermore, alcohol significantly affected mitochondrial bioenergetics, including oxidative phosphorylation and electron transport, with inhibited aerobic respiration in mPFC mitochondria after CIA exposure. We also found decreased expression of fusion (mitofusin 2, Mfn2) and increased fission (mitochondrial fission 1 protein, Fis1) proteins in the mPFC of alcohol-treated mice. In sum, our study suggests that CIA exposure impairs mitochondrial dynamics and function in the mPFC.

Ethanol-activated CaMKII signaling induces neuronal apoptosis through Drp1-mediated excessive mitochondrial fission and JNK1-dependent NLRP3 inflammasome activation

Background

Neurodegeneration is a representative phenotype of patients with chronic alcoholism. Ethanol-induced calcium overload causes NOD-like receptor protein 3 (NLRP3) inflammasome formation and an imbalance in mitochondrial dynamics, closely associated with the pathogenesis of neurodegeneration. However, how calcium regulates this process in neuronal cells is poorly understood. Therefore, the present study investigated the detailed mechanism of calcium-regulated mitochondrial dynamics and NLRP3 inflammasome formation in neuronal cells by ethanol.

Methods

In this study, we used the SK-N-MC human neuroblastoma cell line. To confirm the expression level of the mRNA and protein, real time quantitative PCR and western blot were performed. Co-immunoprecipitation and Immunofluorescence staining were conducted to confirm the complex formation or interaction of the proteins. Flow cytometry was used to analyze intracellular calcium, mitochondrial dysfunction and neuronal apoptosis.

Results

Ethanol increased cleaved caspase-3 levels and mitochondrial reactive oxygen species (ROS) generation associated with neuronal apoptosis. In addition, ethanol increased protein kinase A (PKA) activation and cAMP-response-element-binding protein (CREB) phosphorylation, which increased N-methyl-D-aspartate receptor (NMDAR) expression. Ethanol-increased NMDAR induced intracellular calcium overload and calmodulin-dependent protein kinase II (CaMKII) activation leading to phosphorylation of dynamin-related protein 1 (Drp1) and c-Jun N-terminal protein kinase 1 (JNK1). Drp1 phosphorylation promoted Drp1 translocation to the mitochondria, resulting in excessive mitochondrial fission, mitochondrial ROS accumulation, and loss of mitochondrial membrane potential, which was recovered by Drp1 inhibitor pretreatment. Ethanol-induced JNK1 phosphorylation activated the NLRP3 inflammasome that induced caspase-1 dependent mitophagy inhibition, thereby exacerbating ROS accumulation and causing cell death. Suppressing caspase-1 induced mitophagy and reversed the ethanol-induced apoptosis in neuronal cells.

Conclusions

Our results demonstrated that ethanol upregulated NMDAR-dependent CaMKII phosphorylation which is essential for Drp1-mediated excessive mitochondrial fission and the JNK1-induced NLRP3 inflammasome activation resulting in neuronal apoptosis.

Safety of drug use in patients with a primary mitochondrial disease: An international Delphi-based consensus

Clinical guidance is often sought when prescribing drugs for patients with primary mitochondrial disease. Theoretical considerations concerning drug safety in patients with mitochondrial disease may lead to unnecessary withholding of a drug in a situation of clinical need. The aim of this study was to develop consensus on safe medication use in patients with a primary mitochondrial disease. A panel of 16 experts in mitochondrial medicine, pharmacology, and basic science from six different countries was established. A modified Delphi technique was used to allow the panellists to consider draft recommendations anonymously in two Delphi rounds with predetermined levels of agreement. This process was supported by a review of the available literature and a consensus conference that included the panellists and representatives of patient advocacy groups. A high level of consensus was reached regarding the safety of all 46 reviewed drugs, with the knowledge that the risk of adverse events is influenced both by individual patient risk factors and choice of drug or drug class. This paper details the consensus guidelines of an expert panel and provides an important update of previously established guidelines in safe medication use in patients with primary mitochondrial disease. Specific drugs, drug groups, and clinical or genetic conditions are described separately as they require special attention. It is important to emphasise that consensus-based information is useful to provide guidance, but that decisions related to drug prescribing should always be tailored to the specific needs and risks of each individual patient. We aim to present what is current knowledge and plan to update this regularly both to include new drugs and to review those currently included.

Alcohol consumption during adolescence alters the hippocampal response to traumatic brain injury

Binge drinking is the consumption of large volumes of alcohol in short periods and exerts its effects on the central nervous system, including the hippocampus. We have previously shown that binge drinking alters mitochondrial dynamics and induces neuroinflammation in the hippocampus of adolescent rats. Mild traumatic brain injury (mTBI), is regularly linked to alcohol consumption and share mechanisms of brain damage. In this context, we hypothesized that adolescent binge drinking could prime the development of brain damage generated by mTBI. We found that alcohol binge drinking induced by the "drinking in the dark" (DID) paradigm increases oxidative damage and astrocyte activation in the hippocampus of adolescent mice. Interestingly, adolescent animals submitted to DID showed decreased levels of mitofusin 2 that controls mitochondrial dynamics. When mTBI was evaluated as a second challenge, hippocampi from animals previously submitted to DID showed a reduction in dendritic spine number and a different spine profile. Mitochondrial performance could be compromised by alterations in mitochondrial fission in DID-mTBI animals. These data suggest that adolescent alcohol consumption can modify the progression of mTBI pathophysiology. We propose that mitochondrial impairment and oxidative damage could act as priming factors, modifying predisposition against mTBI effects.

Oroxylin a promotes PGC-1α/Mfn2 signaling to attenuate hepatocyte pyroptosis via blocking mitochondrial ROS in alcoholic liver disease

BACKGROUND

It is well acknowledged that alcoholic liver disease (ALD) is widely prevalent all over the world, characterized by aberrant lipid deposition and excessive oxidative stress in hepatocytes. Recently, pyroptosis, a new type of programmed cell death, has been found in ALD, which provides new ideas for the treatment of ALD.

METHODS

Male ICR mice were treated with the Lieber-De-Carli diet (Dyets) or isocaloric liquid diet for 8 weeks, and binge alcohol model was also used for ALD. Blood and livers were taken to evaluate the efficacy of oroxylin A. The levels of factors related to hepatocyte pyroptosis were measured via western blot analyses, immunofluorescence analyses and quantitative reverse transcriptase in vitro.

RESULT

Our study found that oroxylin A suppressed hepatocyte pyroptosis through a NLRP3 inflammasome dependent-canonical caspase-1 pathway. Results illuminated that oroxylin A inhibited NLRP3 inflammasome activation by reducing ROS accumulation. Furthermore, oroxylin A upregulated mitofusin 2 (Mfn2) to resist lipid deposition and mitochondria-derived ROS overproduction. As an upstream mediator of Mfn2, peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α), a major regulator of mitochondria, was found to promote transcription of Mfn2 under oroxylin A treatment.

CONCLUSION

Our research revealed that oroxylin A could alleviate ALD via PGC-1α/Mfn2 signaling mediated canonical pyroptosis pathway resistance.

Cardiac Function is not Susceptible to Moderate Disassembly of Mitochondrial Respiratory Supercomplexes

Mitochondrial respiratory chain supercomplexes (RCS), particularly, the respirasome, which contains complexes I, III, and IV, have been suggested to participate in facilitating electron transport, reducing the production of reactive oxygen species (ROS), and maintaining the structural integrity of individual electron transport chain (ETC) complexes. Disassembly of the RCS has been observed in Barth syndrome, neurodegenerative and cardiovascular diseases, diabetes mellitus, and aging. However, the physiological role of RCS in high energy-demanding tissues such as the heart remains unknown. This study elucidates the relationship between RCS assembly and cardiac function. Adult male Sprague Dawley rats underwent Langendorff retrograde perfusion in the presence and absence of ethanol, isopropanol, or rotenone (an ETC complex I inhibitor). We found that ethanol had no effects on cardiac function, whereas rotenone reduced heart contractility, which was not recovered when rotenone was excluded from the perfusion medium. Blue native polyacrylamide gel electrophoresis revealed significant reductions of respirasome levels in ethanol- or rotenone-treated groups compared to the control group. In addition, rotenone significantly increased while ethanol had no effect on mitochondrial ROS production. In isolated intact mitochondria in vitro, ethanol did not affect respirasome assembly; however, acetaldehyde, a byproduct of ethanol metabolism, induced dissociation of respirasome. Isopropanol, a secondary alcohol which was used as an alternative compound, had effects similar to ethanol on heart function, respirasome levels, and ROS production. In conclusion, ethanol and isopropanol reduced respirasome levels without any noticeable effect on cardiac parameters, and cardiac function is not susceptible to moderate reductions of RCS.

Alcohol impairs hippocampal function: From NMDA receptor synaptic transmission to mitochondrial function

Many studies have reported that alcohol produces harmful effects on several brain structures, including the hippocampus, in both rodents and humans. The hippocampus is one of the most studied areas of the brain due to its function in learning and memory, and a lot of evidence suggests that hippocampal failure is responsible for the cognitive loss present in individuals with recurrent alcohol consumption. Mitochondria are organelles that generate the energy needed for the brain to maintain neuronal communication, and their functional failure is considered a mediator of the synaptic dysfunction induced by alcohol. In this review, we discuss the mechanisms of how alcohol exposure affects neuronal communication through the impairment of glutamate receptor (NMDAR) activity, neuroinflammatory events and oxidative damage observed after alcohol exposure, all processes under the umbrella of mitochondrial function. Finally, we discuss the direct role of mitochondrial dysfunction mediating cognitive and memory decline produced by alcohol exposure and their consequences associated with neurodegeneration.

Recent Insights into the Mitochondrial Role in Autophagy and Its Regulation by Oxidative Stress

Autophagy is a self-digestive process that degrades intracellular components, including damaged organelles, to maintain energy homeostasis and to cope with cellular stress. Autophagy plays a key role during development and adult tissue homeostasis, and growing evidence indicates that this catalytic process also has a direct role in modulating aging. Although autophagy is essentially protective, depending on the cellular context and stimuli, autophagy outcome can lead to either abnormal cell growth or cell death. The autophagic process requires a tight regulation, with cellular events following distinct stages and governed by a wide molecular machinery. Reactive oxygen species (ROS) have been involved in autophagy regulation through multiple signaling pathways, and mitochondria, the main source of endogenous ROS, have emerged as essential signal transducers that mediate autophagy. In the present review, we aim to summarize the regulatory function of mitochondria in the autophagic process, particularly regarding the mitochondrial role as the coordination node in the autophagy signaling pathway, involving mitochondrial oxidative stress, and their participation as membrane donors in the initial steps of autophagosome assembly.

Analysis of lacrimal gland derived mesenchymal stem cell secretome and its impact on epithelial cell survival

In situ regeneration of lacrimal gland (LG) tissue would be a promising approach to curatively treat dry eye disease (DED). Mesenchymal stem cells (MSC) exhibit therapeutic effects in a variety of pathological conditions and our group recently reported that their number increases in regenerating mouse LG. Since the therapeutic effects are suggested to arise from secreted trophic factors, the application of MSC-secreted proteins seems to be a promising approach to induce/enhance LG regeneration. Therefore, this study aims to optimize the isolation of murine LG-MSC and analyze their secretome to investigate its potential for LG epithelial cell survival in vitro. For optimization, LG-MSC were isolated by an explant technique or cell sorting and their secretome was investigated under normal and inflammatory conditions. Results showed that the secretome of MSC had beneficial effects on the viability of ethanol-damaged LG epithelial cells. Additional, Lipocalin-2, prosaposin, ras GTPase-activating protein-binding protein 1 (Rac1) and signal transducer and activator of transcription 1 (STAT1), proteins that were up-regulated under inflammatory conditions, further improved the cell survival of ethanol-damaged LG epithelial cells. Interestingly, recovery of cell viability was highest, when the cells were incubated with STAT1. Summarizing, this study identified promising proteins for further studies on LG regeneration.

Dynamin-1-Like Protein Inhibition Drives Megamitochondria Formation as an Adaptive Response in Alcohol-Induced Hepatotoxicity

Despite the growing global burden of alcoholic liver diseases, therapeutic options are limited, and novel targets are urgently needed. Accumulating evidence suggests that mitochondria adapt in response to ethanol and formation of megamitochondria in the livers of patients is recognized as a hallmark of alcoholic liver diseases. The processes involved in ethanol-induced hepatic mitochondrial changes, the impact on mitochondria-shaping proteins, and the significance of megamitochondria formation remain unknown. In this study, we investigated the mitochondrial and cellular response to alcohol in hepatoma cell line VL-17A. The mitochondrial architecture rapidly changed after 3 or 14 days of ethanol exposure with double-pronged presentation of hyperfragmentation and megamitochondria, and cell growth was inhibited. Dynamin-1-like protein (Drp1) was identified as the main mediator driving these mitochondrial alterations, and its genetic inactivation was determined to foster megamitochondria development, preserving the capacity of the cells to grow despite alcohol toxicity. The role of Drp1 in mediating megamitochondria formation in mice with liver-specific inactivation of Drp1 was further confirmed. Finally, when these mice were fed with ethanol, the presentation of hepatic megamitochondria was exacerbated compared with wild type fed with the same diet. Ethanol-induced toxicity was also reduced. Our study demonstrates that megamitochondria formation is mediated by Drp1, and this phenomenon is a beneficial adaptive response during alcohol-induced hepatotoxicity.

Differing Impact of Sarcopenia and Frailty in Nonalcoholic Steatohepatitis and Alcoholic Liver Disease

Sarcopenia and frailty are commonly encountered in patients with end-stage liver disease and are associated with adverse clinical outcomes, including decompensation and wait-list mortality. The impact of these entities in patients with differing disease etiologies has not been elucidated. We aim to ascertain the change in their prevalence over time on the wait list and determine their impact on hospitalization, delisting, and wait-list survival, specifically for patients with nonalcoholic steatohepatitis (NASH) and alcoholic liver disease (ALD). Adult patients who were evaluated for their first liver transplant from 2014 to 2016 with a primary diagnosis of NASH (n = 136) or ALD (n = 129) were included. Computed tomography scans were used to determine the presence of sarcopenia and myosteatosis. Frailty was diagnosed using the Rockwood frailty index. Patients with NASH had a significantly lower prevalence of sarcopenia (22% versus 47%; P < 0.001) but a significantly higher prevalence of frailty (49% versus 34%; P = 0.03) when compared with patients with ALD at the time of listing. In patients with NASH, sarcopenia was not associated with adverse events, but a higher frailty score was associated with an increased length of hospitalization (P = 0.05) and an increased risk of delisting (P = 0.02). In patients with ALD, univariate analysis showed the presence of sarcopenia was associated with an increased risk of delisting (P = 0.01). In conclusion, sarcopenia and frailty occur with differing prevalence with variable impact on outcomes in wait-listed patients with NASH and ALD.

Chronic Binge Alcohol-Induced Dysregulation of Mitochondrial-Related Genes in Skeletal Muscle of Simian Immunodeficiency Virus-Infected Rhesus Macaques at End-Stage Disease

Aims

Alcohol use disorders are more prevalent in HIV patients than the general population. Both chronic alcohol consumption and HIV infection have been linked to mitochondrial dysregulation; and this is considered an important mechanism in the pathogenesis of muscle myopathy. This study investigated if chronic binge alcohol (CBA) administration impairs the expression of genes involved in mitochondrial homeostasis in SIV-infected macaques.

Methods

Male rhesus macaques were administered daily CBA (to achieve peak blood alcohol concentrations of 50-60 mM within 2 h after start of infusion) or sucrose (SUC) intragastrically 3 months prior to intravenous SIVmac251 inoculation and continued until macaques met criteria for end-stage disease. Skeletal muscle (SKM) samples were obtained at necropsy. Muscle samples were obtained from a cohort of healthy uninfected macaque controls and used for comparison of analyzed variables. Total RNA was extracted and gene expression was analyzed by quantitative polymerase chain reaction.

Results

The relative expression of peroxisome proliferator-activated receptor gamma coactivator-1 beta (PGC-1β) was significantly decreased in the SKM of CBA/simian immunodeficiency virus (SIV) macaques compared to uninfected controls (P < 0.05). SIV infection resulted in a significant upregulation (P < 0.05) of mitophagy-related gene expression, which was prevented by CBA. CBA suppressed expression of anti-apoptotic genes and increased expression of pro-apoptotic genes (P < 0.05).

Conclusions

These findings suggest that SIV infection disrupts mitochondrial homeostasis and when combined with CBA, results in differential expression of genes involved in apoptotic signaling. We speculate that impaired mitochondrial homeostasis may contribute to the underlying pathophysiology of alcoholic and HIV/AIDS associated myopathy.

Short summary

This study investigated if CBA administration dysregulates gene expression associated with mitochondrial homeostasis in the SKM of SIV-infected macaques. The results suggest that SIV infection disrupts mitochondrial homeostasis and when combined with CBA, results in differential expression of genes involved in apoptotic signaling.

Role of retinal pigment epithelium-derived exosomes and autophagy in new blood vessel formation

Autophagy and exosome secretion play important roles in a variety of physiological and disease states, including the development of age‐related macular degeneration. Previous studies have demonstrated that these cellular mechanisms share common pathways of activation. Low oxidative damage in ARPE‐19 cells, alters both autophagy and exosome biogenesis. Moreover, oxidative stress modifies the protein and genetic cargo of exosomes, possibly affecting the fate of surrounding cells. In order to understand the connection between these two mechanisms and their impact on angiogenesis, stressed ARPE‐19 cells were treated with a siRNA‐targeting Atg7, a key protein for the formation of autophagosomes. Subsequently, we observed the formation of multivesicular bodies and the release of exosomes. Released exosomes contained VEGFR2 as part of their cargo. This receptor for VEGF—which is critical for the development of new blood vessels—was higher in exosome populations released from stressed ARPE‐19. While stressed exosomes enhanced tube formation, exosomes became ineffective after silencing VEGFR2 in ARPE‐19 cells and were, consequently, unable to influence angiogenesis. Moreover, vessel sprouting in the presence of stressed exosomes seems to follow a VEGF‐independent pathway. We propose that abnormal vessel growth correlates with VEGFR2‐expressing exosomes release from stressed ARPE‐19 cells, and is directly linked to autophagy.

Methyl ferulic acid exerts anti-apoptotic effects on L-02 cells via the ROS-mediated signaling pathway

The present study aimed to investigate the anti-apoptotic effects of methyl ferulic acid (MFA) on L-02 cell apoptosis induced by ethanol, and to elucidate the possible underlying mechanisms. L-02 cells were examined after being soaked in ethanol (400 mM) to allow the ethanol to permeate into the cells for 24 h. Cell survival was measured by MTT assay. Cell apoptosis was assessed by both flow cytometry and single-stranded DNA assays. Intracellular reactive oxygen species (ROS) production was determined using the 2',7'-dichlorofluorescein-diacetate dye. The protein expression levels of p38, p-p38, JNK, p-JNK, NADPH oxidase 4 (NOX4), p22, Bax and Bcl-2 were measured by western blot analysis. The mRNA expression levels of NOX4 and p22 were measured by RT-PCR. It was identified that MFA markedly suppressed the ethanol-induced apoptosis and necrosis of L-02 cells. In addition, MFA decreased the expression levels of superoxide dismutase, catalase and phospholipid hydroperoxide gluthione peroxidase, and downregulated the levels of Bax/Bcl-2 and the cleaved forms of caspase-3 in a dose- and time-dependent manner. This indicated that MFA attenuated the apoptosis of L-02 cells. MFA also decreased the elevated mRNA and protein expression levels of Nox4 and p22phox, and the production of intracellular ROS triggered by ethanol. Further analysis demonstrated that MFA significantly attenuated the phosphorylation of JNK and p38, which are major components of the mitogen-activated protein kinase (MAPK) pathways. On the whole, the findings of this study demonstrated that MFA attenuated the apoptotic cell death of L-02 cells by reducing the generation of ROS and inactivating the MAPK pathways.

The effect of interaction between EtOH dosage and exposure time on gene expression in DPSC

Alcohol (EtOH) dosage and exposure time can affect gene expression. However, whether there exists synergistic effect is unknown. Here, we analyzed the hDPSC gene microarray dataset GSE57255 downloaded from Gene Expression Omnibus and found that the interaction between EtOH dosage and exposure time on gene expression are statistically significant for two probes: 201917_s_at near gene SLC25A36 and 217649_at near gene ZFAND5. GeneMania showed that SLC25A36 and ZFAND5 were related to 20 genes, three of which had alcohol-related functions. WebGestalt revealed that the 22 genes were enriched in 10 KEGG pathways, four of which are related to alcoholic diseases. We explored the possible nonlinear interaction effect and got 172 gene probes with significant p-values. However, no significantly enriched pathways based on the 172 probes were detected. Our analyses indicated a possible molecular mechanism that could help explain why alcohol consumption has both deleterious and beneficial effects on human health.

PINK1/Parkin-mediated mitophagy was activated against 1,4-Benzoquinone-induced apoptosis in HL-60 cells

Hematotoxicity of benzene is derived mainly from its active metabolite, 1,4-Benzoquinone (1,4-BQ), which induces cell apoptosis and mitochondrial damage. Damaged mitochondria are degraded through a specialized autophagy pathway, called mitophagy, which is driven by PINK1/Parkin signaling. However, whether mitophagy is involved in 1,4-BQ-induced toxicity remains unclear. This study was designed to investigate whether PINK1/Parkin-mediated mitophagy is activated in 1,4-BQ-treated HL-60 cells, and the roles mitophagy plays in 1,4-BQ-induced apoptosis. Our results demonstrated that 1,4-BQ induced autophagy in HL-60 cells, characterized by increased LC3-II/LC3-I ratio and Beclin1 expression, as well as decreased expression of p62. We confirmed the presence of mitophagosomes using electron microscopy, and found that 1,4-BQ-induced autophagy was blocked by pretreatment with the mitophagy inhibitor Cyclosporine A (CsA). In addition, we found that 1,4-BQ induced mitochondrial stress through decreased mitochondrial membrane potential (MMP) and increasedproduction of reactive oxygen species (ROS). We also confirmed that 1,4-BQ-induced mitophagy was mediated by the PINK1/Parkin pathway, illustrated by increased expression of PINK1 and Parkin mRNA and protein. Finally, we examined 1,4-BQ-induced apoptosis with or without CsA, which demonstrated that apoptosis increased after mitophagy inhibition, suggesting that mitophagy has a protective effect in this context. In conclusion, this study demonstrates that the activated PINK1/Parkin-mediated mitophagy exerts a significantly protective effect against 1,4-BQ-induced apoptosis in HL-60 cells.

Myoblast mitochondrial respiration is decreased in chronic binge alcohol administered simian immunodeficiency virus-infected antiretroviral-treated rhesus macaques

Work from our group demonstrated that chronic binge alcohol (CBA)-induces mitochondrial gene dysregulation at end-stage disease of simian immunodeficiency virus (SIV) infection in antiretroviral therapy (ART) naïve rhesus macaques. Alterations in gene expression can disrupt mitochondrial homeostasis and in turn contribute to the risk of metabolic comorbidities characterized by loss of skeletal muscle (SKM) functional mass that are associated with CBA, human immunodeficiency virus (HIV) infection, and prolonged ART. The aim of this study was to examine the interaction of CBA and ART on SKM fiber oxidative capacity and myoblast mitochondrial respiration in asymptomatic SIV-infected macaques. SKM biopsies were obtained and myoblasts isolated at baseline and 11 months post-SIV infection from CBA/SIV/ART+ and from sucrose (SUC)-treated SIV-infected (SUC/SIV/ART+) macaques. CBA and ART decreased succinate dehydrogenase (SDH) activity in type 1 and type 2b fibers as determined by immunohistochemistry. Myoblasts isolated from CBA/SIV/ART+ macaques showed decreased maximal oxygen consumption rate (OCR) compared to myoblasts from control macaques. Maximal OCR was significantly increased in control myoblasts following incubation with formoterol, a beta adrenergic agonist, and this was associated with increased PGC-1α expression and mtDNA quantity. Additionally, formoterol treatment of myoblasts isolated from CBA/SIV/ART+ macaques partially restored maximal OCR to levels not significantly different from control. These results show that CBA in combination with ART impairs myoblast mitochondrial homeostasis in SIV-infected macaques. Moreover, our findings suggest that adrenergic agonists can potentially ameliorate mitochondrial dysfunction. Future studies will elucidate whether physical exercise in HIV patients with alcohol use disorder can improve mitochondrial health.

Nutrition and Muscle in Cirrhosis

As the cirrhosis progresses, development of complication like ascites, hepatic encephalopathy, variceal bleeding, kidney dysfunction, and hepatocellular carcinoma signify increasing risk of short term mortality. Malnutrition and muscle wasting (sarcopenia) is yet other complications that negatively impact survival, quality of life, and response to stressors, such as infection and surgery in patients with cirrhosis. Conventionally, these are not routinely looked for, because nutritional assessment can be a difficult especially if there is associated fluid retention and/or obesity. Patients with cirrhosis may have a combination of loss of skeletal muscle and gain of adipose tissue, culminating in the condition of "sarcopenic obesity." Sarcopenia in cirrhotic patients has been associated with increased mortality, sepsis complications, hyperammonemia, overt hepatic encephalopathy, and increased length of stay after liver transplantation. Assessment of muscles with cross-sectional imaging studies has become an attractive index of nutritional status evaluation in cirrhosis, as sarcopenia, the major component of malnutrition, is primarily responsible for the adverse clinical consequences seen in patients with liver disease. Cirrhosis is a state of accelerated starvation, with increased gluconeogenesis that requires amino acid diversion from other metabolic functions. Protein homeostasis is disturbed in cirrhosis due to several factors such as hyperammonemia, hormonal, and cytokine abnormalities, physical inactivity and direct effects of ethanol and its metabolites. New approaches to manage sarcopenia are being evolved. Branched chain amino acid supplementation, Myostatin inhibitors, and mitochondrial protective agents are currently in various stages of evaluation in preclinical studies to prevent and reverse sarcopenia, in cirrhosis.

Sarcopenia in Alcoholic Liver Disease: Clinical and Molecular Advances

Despite advances in treatment of alcohol use disorders that focus on increasing abstinence and reducing recidivism, alcoholic liver disease (ALD) is projected to be the major cause of cirrhosis and its complications. Malnutrition is recognized as the most frequent complication in ALD, and despite the high clinical significance, there are no effective therapies to reverse malnutrition in ALD. Malnutrition is a relatively imprecise term, and sarcopenia or skeletal muscle loss, the major component of malnutrition, is primarily responsible for the adverse clinical consequences in patients with liver disease. It is, therefore, critical to define the specific abnormality (sarcopenia) rather than malnutrition in ALD, so that therapies targeting sarcopenia can be developed. Skeletal muscle mass is maintained by a balance between protein synthesis and proteolysis. Both direct effects of ethanol (EtOH) and its metabolites on the skeletal muscle and the consequences of liver disease result in disturbed proteostasis (protein homeostasis) and consequent sarcopenia. Once cirrhosis develops in patients with ALD, abstinence is unlikely to be effective in completely reversing sarcopenia, as other contributors including hyperammonemia, hormonal, and cytokine abnormalities aggravate sarcopenia and maintain a state of anabolic resistance initiated by EtOH. Cirrhosis is also a state of accelerated starvation, with increased gluconeogenesis that requires amino acid diversion from signaling and substrate functions. Novel therapeutic options are being recognized that are likely to supplant the current "deficiency replacement" approach and instead focus on specific molecular perturbations, given the increasing availability of small molecules that can target specific signaling components. Myostatin antagonists, leucine supplementation, and mitochondrial protective agents are currently in various stages of evaluation in preclinical studies to prevent and reverse sarcopenia, in cirrhosis in general, and ALD, specifically. Translation of these data to human studies and clinical application requires priority for allocation of resources.

Disruption of retinal pigment epithelial cell properties under the exposure of cotinine

Cigarette smoking is a major risk factor for age-related macular degeneration (AMD), in which progressive retinal pigment epithelial (RPE) cell degeneration is a major pathological change. Nicotine is a major biologically active component in cigarette smoke. It is continuously catabolized into cotinine, which has longer half-life and higher concentration in tissue cells and fluids. Here we hypothesized that continuous exposure of cotinine has more potent effects on human RPE cell properties than nicotine. Human RPE cell line (ARPE-19) was treated continuously with 1-2 µM of nicotine and/or cotinine for 7 days. RPE cells treated with 2 μM cotinine and nicotine-cotinine mixture has lower MTT signals without significant changes in cell apoptosis or integrity. Moreover, RPE cell migration was retarded under cotinine treatments, but not nicotine. Both nicotine and cotinine treatments attenuated the phagocytotic activity of RPE cells. In addition, cotinine and nicotine-cotinine mixture suppressed VEGF and IL-8 expression and upregulated TIMP-2 expression. Expressions of autophagy genes were upregulated by the cotinine treatment, whereas expressions of epithelial-to-mesenchymal transition markers were downregulated. In conclusion, our study, for the first time, demonstrated that cotinine, rather than nicotine, affects the properties of RPE cells in vitro, which could explain the smoking-induced RPE pathology.

FoxO1-AMPK-ULK1 Regulates Ethanol-Induced Autophagy in Muscle by Enhanced ATG14 Association with the BECN1-PIK3C3 Complex

BACKGROUND

Excessive alcohol (EtOH) consumption causes an imbalance in protein metabolism. EtOH impairs protein synthesis in C2C12 myoblasts via a FoxO1-AMPK-TSC2-mTORC1 pathway and also induces protein degradation. As the underlying regulatory signaling cascades for these processes are currently poorly defined, we tested the hypothesis that alcohol-induced autophagy is mediated via activation of the PIK3C3 complex that is regulated by FoxO1-AMPK.

METHODS

C2C12 myoblasts were incubated with EtOH for various periods of time, and autophagy pathway-related proteins were assessed by Western blotting and immunoprecipitation. Expression of targeted genes was suppressed using electroporation of specific siRNAs and chemical inhibitors.

RESULTS

Incubation of C2C12 myoblasts with 100 mM EtOH increased the autophagy markers LC3B-II and ATG7, whereas levels of SQSTM1/p62 decreased. The lysosomal inhibitor bafilomycin A1 caused a similar response, although there was no additive effect when combined with EtOH. EtOH altered ULK1 S555 and S757 phosphorylation in a time- and AMPK-dependent manner. The activation of AMPK and ULK1 was associated with increased BECN1 (S93, S14) and PIK3C3/VPS34 (S164) phosphorylation as well as increased total ATG14 and PIK3C3. These changes promoted formation of the ATG14-AMBRA1-BECN1-PIK3C3 proautophagy complex that is important in autophagosome formation. EtOH-induced changes were not associated with increased production of PtdIns3P, which may be due to enhanced PIK3C3 complex binding with 14-3-3θ. Reduction of AMPK using siRNA suppressed the stimulatory effect of EtOH on BECN1 S93, BECN1 S14, and PIK3C3 S164 phosphorylation in a time-dependent manner. Likewise, knockdown of AMPK or chemical inhibition of FoxO1 attenuated phosphorylation of ULK1 at both residues. Knockdown of ULK1 or BECN1 antagonized the effect of EtOH on LC3B-II, SQSTM1, and ATG7 protein expression.

CONCLUSIONS

EtOH-induced autophagy is mediated through changes in phosphorylation and interaction of various PIK3C3 complex components. This, in turn, is regulated either directly via FoxO1-AMPK or indirectly via the FoxO1-AMPK-ULK1 signaling cascade in a mTORC1-independent or mTORC1-dependent manner.

Continuous exposure to non-lethal doses of sodium iodate induces retinal pigment epithelial cell dysfunction

Age-related macular degeneration (AMD), characterized by progressive degeneration of retinal pigment epithelium (RPE), is the major cause of irreversible blindness and visual impairment in elderly population. We previously established a RPE degeneration model using an acute high dose sodium iodate to induce oxidative stress. Here we report findings on a prolonged treatment of low doses of sodium iodate on human RPE cells (ARPE-19). RPE cells were treated continuously with low doses (2-10 mM) of sodium iodate for 5 days. Low doses (2-5 mM) of sodium iodate did not reduce RPE cell viability, which is contrasting to cell apoptosis in 10 mM treatment. These low doses are sufficient to retard RPE cell migration and reduced expression of cell junction protein ZO-1. Phagocytotic activity of RPE cells was attenuated by sodium iodate dose-dependently. Sodium iodate also increased expression of FGF-2, but suppressed expression of IL-8, PDGF, TIMP-2 and VEGF. Furthermore, HTRA1 and epithelial-to-mesenchymal transition marker proteins were downregulated, whereas PERK and LC3B-II proteins were upregulated after sodium iodate treatment. These results suggested that prolonged exposure to non-lethal doses of oxidative stress induces RPE cell dysfunctions that resemble conditions in AMD. This model can be used for future drug/treatment investigation on AMD.

Autophagy in the eye: Development, degeneration, and aging

Autophagy is a catabolic pathway that promotes the degradation and recycling of cellular components. Proteins, lipids, and even whole organelles are engulfed in autophagosomes and delivered to the lysosome for elimination. In response to stress, autophagy mediates the degradation of cell components, which are recycled to generate the nutrients and building blocks required to sustain cellular homeostasis. Moreover, it plays an important role in cellular quality control, particularly in neurons, in which the total burden of altered proteins and damaged organelles cannot be reduced by redistribution to daughter cells through cell division. Research has only begun to examine the role of autophagy in the visual system. The retina, a light-sensitive tissue, detects and transmits electrical impulses through the optic nerve to the visual cortex in the brain. Both the retina and the eye are exposed to a variety of environmental insults and stressors, including genetic mutations and age-associated alterations that impair their function. Here, we review the main studies that have sought to explain autophagy's importance in visual function. We describe the role of autophagy in retinal development and cell differentiation, and discuss the implications of autophagy dysregulation both in physiological aging and in important diseases such as age-associated macular degeneration and glaucoma. We also address the putative role of autophagy in promoting photoreceptor survival and discuss how selective autophagy could provide alternative means of protecting retinal cells. The findings reviewed here underscore the important role of autophagy in maintaining proper retinal function and highlight novel therapeutic approaches for blindness and other diseases of the eye.

Oxidative stress in retinal pigment epithelium cells increases exosome secretion and promotes angiogenesis in endothelial cells

The retinal pigment epithelium (RPE), a monolayer located between the photoreceptors and the choroid, is constantly damaged by oxidative stress, particularly because of reactive oxygen species (ROS). As the RPE, because of its physiological functions, is essential for the survival of the retina, any sustained damage may consequently lead to loss of vision. Exosomes are small membranous vesicles released into the extracellular medium by numerous cell types, including RPE cells. Their cargo includes genetic material and proteins, making these vesicles essential for cell-to-cell communication. Exosomes may fuse with neighbouring cells influencing their fate. It has been observed that RPE cells release higher amounts of exosomes when they are under oxidative stress. Exosomes derived from cultured RPE cells were isolated by ultracentrifugation and quantified by flow cytometry. VEGF receptors (VEGFR) were analysed by both flow cytometry and Western blot. RT-PCR and qPCR were conducted to assess mRNA content of VEGFRs in exosomes. Neovascularization assays were performed after applying RPE exosomes into endothelial cell cultures. Our results showed that stressed RPE cells released a higher amount of exosomes than controls, with a higher expression of VEGFR in the membrane, and enclosed an extra cargo of VEGFR mRNA. Angiogenesis assays confirmed that endothelial cells increased their tube formation capacity when exposed to stressed RPE exosomes.

Dynamin-related Protein 1 Inhibition Mitigates Bisphenol A-mediated Alterations in Mitochondrial Dynamics and Neural Stem Cell Proliferation and Differentiation

The regulatory dynamics of mitochondria comprises well orchestrated distribution and mitochondrial turnover to maintain the mitochondrial circuitry and homeostasis inside the cells. Several pieces of evidence suggested impaired mitochondrial dynamics and its association with the pathogenesis of neurodegenerative disorders. We found that chronic exposure of synthetic xenoestrogen bisphenol A (BPA), a component of consumer plastic products, impaired autophagy-mediated mitochondrial turnover, leading to increased oxidative stress, mitochondrial fragmentation, and apoptosis in hippocampal neural stem cells (NSCs). It also inhibited hippocampal derived NSC proliferation and differentiation, as evident by the decreased number of BrdU- and β-III tubulin-positive cells. All these effects were reversed by the inhibition of oxidative stress using N-acetyl cysteine. BPA up-regulated the levels of Drp-1 (dynamin-related protein 1) and enhanced its mitochondrial translocation, with no effect on Fis-1, Mfn-1, Mfn-2, and Opa-1 in vitro and in the hippocampus. Moreover, transmission electron microscopy studies suggested increased mitochondrial fission and accumulation of fragmented mitochondria and decreased elongated mitochondria in the hippocampus of the rat brain. Impaired mitochondrial dynamics by BPA resulted in increased reactive oxygen species and malondialdehyde levels, disruption of mitochondrial membrane potential, and ATP decline. Pharmacological (Mdivi-1) and genetic (Drp-1siRNA) inhibition of Drp-1 reversed BPA-induced mitochondrial dysfunctions, fragmentation, and apoptosis. Interestingly, BPA-mediated inhibitory effects on NSC proliferation and neuronal differentiations were also mitigated by Drp-1 inhibition. On the other hand, Drp-1 inhibition blocked BPA-mediated Drp-1 translocation, leading to decreased apoptosis of NSC. Overall, our studies implicate Drp-1 as a potential therapeutic target against BPA-mediated impaired mitochondrial dynamics and neurodegeneration in the hippocampus.

Autophagy in ethanol-exposed liver disease

Ethanol metabolism in hepatocytes causes the generation of reactive oxygen species, endoplasmic reticulum stress and alterations in mitochondrial energy and REDOX metabolism. In ethanol-exposed liver disease, autophagy not only acts as a cleanser to remove damaged organelles and cytosolic components, but also selectively clears specific targets such as lipid droplets and damaged mitochondria. Moreover, ethanol appears to play a role in protecting hepatocytes from apoptosis at certain concentrations. This article describes the evidence, function and potential mechanism of autophagy in ethanol-exposed liver disease and the controversy surrounding the effects of ethanol on autophagy.

Adoptive Autophagy Activation: a Much-Needed Remedy Against Chemical Induced Neurotoxicity/Developmental Neurotoxicity

The profound significance of autophagy as a cell survival mechanism under conditions of metabolic stress is a well-proven fact. Nearly a decade-long research in this area has led scientists to unearth various roles played by autophagy other than just being an auto cell death mechanism. It is implicated as a vital cell survival pathway for clearance of all the aberrant cellular materials in case of cellular injury, metastasis, disease states, cellular stress, neurodegeneration and so on. In this review, we emphasise the critical role of autophagy in the environmental stressors-induced neurotoxicity and its therapeutic implications for the same. We also attempt to shed some light on the possible protective role of autophagy in developmental neurotoxicity (DNT) which is a rapidly growing health issue of the human population at large and hence a point of rising concern amongst researchers. The intimate association between DNT and neurodegenerative disorders strongly indicates towards adopting autophagy activation as a much-needed remedy for DNT.

Quercetin Attenuates Chronic Ethanol-Induced Hepatic Mitochondrial Damage through Enhanced Mitophagy

Emerging evidence suggested mitophagy activation mitigates ethanol-induced liver injury. However, the effect of ethanol on mitophagy is inconsistent. Importantly, the understanding of mitophagy status after chronic ethanol consumption is limited. This study evaluated the effect of quercetin, a naturally-occurring flavonoid, on chronic ethanol-induced mitochondrial damage focused on mitophagy. An ethanol regime to mice for 15 weeks (accounting for 30% of total calories) led to significant mitochondrial damage as evidenced by changes of the mitochondrial ultrastructure, loss of mitochondrial membrane potential and remodeling of membrane lipid composition, which was greatly attenuated by quercetin (100 mg/kg.bw). Moreover, quercetin blocked chronic ethanol-induced mitophagy suppression as denoted by mitophagosomes-lysosome fusion and mitophagy-related regulator elements, including LC3II, Parkin, p62 and voltage-dependent anion channel 1 (VDAC1), paralleling with increased FoxO3a nuclear translocation. AMP-activated protein kinase (AMPK) and extracellular signal regulated kinase 2 (ERK2), instead of AKT and Sirtuin 1, were involved in quercetin-mediated mitophagy activation. Quercetin alleviated ethanol-elicited mitochondrial damage through enhancing mitophagy, highlighting a promising preventive strategy for alcoholic liver disease.