Mitochondrial dysfunction and oxidative stress in the pathogenesis of alcohol- and obesity-induced fatty liver diseases

Gut Microbiota Disorders and Metabolic Syndrome: Tales of a Crosstalk Process

The microbiota in humans consists of trillions of microorganisms that are involved in the regulation of the gastrointestinal tract and immune and metabolic homeostasis. The gut microbiota (GM) has a prominent impact on the pathogenesis of metabolic syndrome (MetS). This process is reciprocal, constituting a crosstalk process between the GM and MetS. In this review, GM directly or indirectly inducing MetS via the host-microbial metabolic axis has been systematically reviewed. Additionally, the specifically altered GM in MetS are detailed in this review. Moreover, short-chain fatty acids (SCFAs), as unique gut microbial metabolites, have a remarkable effect on MetS, and the role of SCFAs in MetS-related diseases is highlighted to supplement the gaps in this area. Finally, the existing therapeutics are outlined, and the superiority and shortcomings of different therapeutic approaches are discussed, in hopes that this review can contribute to the development of potential treatment strategies.

Mechanisms of rifaximin inhibition of hepatic fibrosis in mice with metabolic dysfunction associated steatohepatitis through the TLR4/NFκB pathway

Metabolic dysfunction-associated steatohepatitis (MASH) has become a serious public health problem, posing an increasingly dangerous threat to human health owing to its increasing prevalence and accompanying intra- and extrahepatic adverse outcomes. Rifaximin is considered to have therapeutic potential for MASH; however, its efficacy remains controversial. Our study aimed to observe the ameliorative effects of rifaximin and explore its possible mechanisms at the cellular level. 1. 42 male C57BL/6J mice were divided into 3 groups, the CON group and MCD group were fed with normal feed and MCD feed for 12 weeks respectively, and the MCD + RFX group was treated with rifaximin by gavage for 4 weeks on the basis of MCD feed. Hematoxylin-eosin staining, Sirius red staining and immunohistochemical staining were used to observe the histopathological changes of liver and intestine. Differences in liver transaminases, inflammatory factors, fibrosis indexes and intestinal tight junction proteins were compared among the 3 groups of mice. 2. A MASH cell model was constructed by inducing HepG2 cells with free fatty acids to observe the effects of rifaximin on MASH in vitro. In addition, the effects of rifaximin on TLR4/NF-κB signaling pathway were explored by applying TLR4 agonist LPS and TLR4 inhibitor TAK-242. Hepatic histopathology was significantly improved in MASH mice after rifaximin treatment, and their serum alanine aminotransferase and aspartate aminotransferase levels were (72.72 ± 5.68) U/L and (222.8 ± 11.22) U/L, respectively, which were significantly lower than those in the MCD group [(293.3 ± 10.69) U/L and (414.1 ± 36.29) U/L, P < 0.05], and the levels of inflammatory factors and fibrosis indicators were reduced. Rifaximin ameliorated intestinal barrier injury with increased expression of intestinal tight junction protein ZO-1 in the MCD + RFX group of mice, and the concentration of LPS-binding proteins (4.92 ± 0.55 vs. 15.82 ± 1.71, P < 0.05) was lower than that in the MCD group. In the NASH cell model, rifaximin similarly exerted inhibitory effects on its inflammatory factors and TLR4/NF-κB signaling pathway. Application of TLR4 inhibitors weakened the inhibitory effect of rifaximin on MASH. Our study supports rifaximin as a potential treatment for MASH, with potential mechanisms related to improving intestinal barrier integrity and downregulating the TLR4/NF-κB signaling pathway.

Mitochondrial targeted therapies in MAFLD

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a clinical-pathological syndrome primarily characterized by excessive accumulation of fat in hepatocytes, independent of alcohol consumption and other well-established hepatotoxic agents. Mitochondrial dysfunction is widely acknowledged as a pivotal factor in the pathogenesis of various diseases, including cardiovascular diseases, cancer, neurodegenerative disorders, and metabolic diseases such as obesity and obesity-associated MAFLD. Mitochondria are dynamic cellular organelles capable of modifying their functions and structures to accommodate the metabolic demands of cells. In the context of MAFLD, the excess production of reactive oxygen species induces oxidative stress, leading to mitochondrial dysfunction, which subsequently promotes metabolic disorders, fat accumulation, and the infiltration of inflammatory cells in liver and adipose tissue. This review aims to systematically analyze the role of mitochondria-targeted therapies in MAFLD, evaluate current therapeutic strategies, and explore future directions in this rapidly evolving field. We specifically focus on the molecular mechanisms underlying mitochondrial dysfunction, emerging therapeutic approaches, and their clinical implications. This is of significant importance for the development of new therapeutic approaches for these metabolic disorders.

Protective effects of CoQ10 and L-carnitine against antidepressant-induced mitochondrial dysfunction and teratogenicity in chicken embryos

Fluoxetine (FXT) and alprazolam (APZ), widely used for mental disorders, have poorly studied adverse effects on mitochondrial function, including oxidative phosphorylation, electron transport, and membrane permeability. This study represents the first investigation using a chick embryo model (HH-stage 10, day 1.5) to analyze the teratogenic effects of FXT and APZ and explore the protective potential of coenzyme Q10 (CoQ10) and L-carnitine (CNT). Administration of FXT (10 μM) and APZ (1 μM) resulted in high teratogenic rates of 53 % and 80 %, respectively, predominantly manifesting as lipid myopathy in hatching muscles, characterized by lipid accumulation, myofibril disruption, inflammation, and edema. Gene expression analysis revealed upregulation of acetyl-CoA carboxylase (ACC) and downregulation of carnitine palmitoyltransferase 1 (CPT1), leading to impaired lipid peroxidation and excessive reactive oxygen species (ROS) production. Markers of oxidative stress, including superoxide dismutase (SOD), hydrogen peroxide (H2O2), and nitric oxide (NO), were significantly elevated, correlating with glutathione (GSH) depletion and mitochondrial ultrastructural damage, resulting in reduced ATP production. Notably, co-administration of CoQ10 and CNT with FXT or APZ significantly improved teratogenic and mortality rates and reduced oxidative stress levels. Specifically, CoQ10 (2 μM) in the FXT group significantly reduced SOD, H2O2, and NO levels, while co-treatment with CNT and CoQ10 (2 μM) in the APZ group significantly alleviated NO levels. This pioneering study highlights the novel and crucial potential of CoQ10 and CNT as nutritional supplements to mitigate mitochondrial damage and antioxidant system imbalance caused by FXT and APZ, providing an innovative strategy for clinical application.

Fluorescent probes for detecting and imaging mitochondrial hydrogen sulfide

Hydrogen sulfide (H2S) is a potent redox-active signaling molecule commonly dysregulated in disease states. The production of H2S and its involvement in various pathological conditions associated with mitochondrial dysfunction have extensively documented. During stress, cystathionine gamma-lyase and cystathionine beta-synthase in cytosol are copiously translocated into the mitochondria to boost H2S production, confirming its pivotal role in mitochondrial activities. However, little study has been done on H2S levels in tissues, cells and organelles, mainly due to the absence of precise and accurate detection tools. Thus, there is an urgent need to determine and monitor the levels of H2S in these important organelles. Fluorescent probes are efficient tools for detecting and monitoring various important biomolecules including biological thiols. The development of fluorescent probes is a multi-pronged approach which involves coupling fluorophores with responsive sites. The use of fluorescent probes for monitoring mitochondrial H2S levels has recently received widespread attention, resulting in numerous publications depicting their synthesis, mechanism of action, application, and potential challenges. Fluorescent probes offer precise and timely results, high sensitivity and selectivity, low biotoxicity, and minimal background interference. In this review, we aim to report designs of such probes, reaction mechanisms and their application in detecting mitochondrial H2S levels. Fluorescent probes can help uncover physio/pathological levels of H2S in essential organelles, its interactions with various biomarkers and associated consequences in biological systems.

Ferric ammonium citrate regulates iron death in mature porcine oocytes and their embryonic development in vitro through the NRF2 signaling pathway

Iron death is a novel type of programmed cell death caused by excessive accumulation of iron-dependent lipid peroxidation products; however, the function of iron death during porcine oocyte maturation and embryo growth is poorly understood. This study was conducted to investigate the mechanism of ferric ammonium citrate (FAC) in regulating iron death in mature oocytes in vitro through the NRF2 signaling pathway, and subsequent embryonic development. The experiment was divided into four groups: 0 (control group), 2, 5, and 10 μM FAC. Western blotting (WB), reactive oxygen species (ROS)assays, mitochondrial membrane potential (MMP) assays, and Quantitative real-time polymerase chain reaction (qRT-PCR) were used to detect the maturation of porcine oocytes in vitro, the protein content of nuclear transcription factor E2-related factor 2 (Nrf2), the distribution of mitochondria, the level of oxidative stress, and the development of embryos fertilized in vitro. The results showed that with increasing FAC concentrations, the oocyte maturation rate in vitro, Nrf2 protein content, MMP, and cleavage rates of in vitro fertilized embryos decreased (significantly in the 5 μM group); the oxidative stress level was significantly increased; the transcript levels of Nrf2, GPX4, and FTH1 mRNAs were significantly decreased; the expression of ACSL4 was significantly upregulated (P < 0.05); and the blastocyst rate of embryos fertilized in vitro was reduced (significantly in the 2 μM group). In conclusion, FAC can regulate Nrf2 protein levels in porcine oocytes matured in vitro to induce iron death, affecting the maturation rate of oocytes, distribution of mitochondria, level of oxidative stress, expression of iron-death-related genes, and development of embryos after in vitro fertilization.

Nicotine aggravates high-fat diet-induced non-alcoholic fatty liver disease in mice via inhibition of CISD3

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease globally. Growing data suggests that smoking plays an important role in the evolution of NAFLD. CDGSH iron sulfur domain 3 (CISD3) regulates critical biological activities. However, its role in nicotine-associated NAFLD and its underlying mechanisms have not been elucidated. Mice were given a high-fat diet for 10 weeks to induce the development of NAFLD. The results revealed that in mice with NAFLD, nicotine treatment resulted in reduced CISD3 expression, leading to mitochondrial dysfunction and impaired β-oxidation. Notably, exacerbation of hepatic steatosis and inflammatory injury was observed. Furthermore, Cisd3-knockout exacerbated lipid accumulation, aggravating oxidative stress and apoptosis. In conclusion, these results contribute to our knowledge of the function of CISD3 in nicotine-associated NAFLD, revealing the possibility of using CISD3 as a potential molecular target for treating NAFLD.

Associations of dietary sources of antioxidant intake and NAFLD: NHANES 2017-2020 and Mendelian randomization

Purpose

To determine the association between dietary antioxidant sources and non-alcoholic fatty liver disease (NAFLD).

Methods

In this observational study, we utilized NHANES 2017-2020 data to identify the factors associated with NAFLD in dietary antioxidant sources via weighted multivariate logistic regression models. Then, Mendelian randomization (MR) was applied to investigate the effect of dietary antioxidant sources on NAFLD at the genetic level.

Results

Of the six dietary sources of antioxidants, only vitamin E (Vit E) was significantly associated with NAFLD (OR = 0.98; 95% CI: 0.97-0.99; p = 0.001). Upon adjusting for all covariates, it was determined that the highest quartile of dietary Vit E intake was associated with a decreased NAFLD occurrence compared with the lowest quartile of dietary Vit E intake (p < 0.001). The results of IVW-MR analysis revealed an association between Vit E and NAFLD (OR = 0.028; p = 0.039).

Conclusion

Our research indicates a negative and linear relationship between daily vitamin E intake and NAFLD.

New Application of an Old Drug: Anti-Diabetic Properties of Phloroglucinol

Phloroglucinol (PHG), an analgesic and spasmolytic drug, shows promise in preventing high-fat-diet (HFD)-induced non-alcoholic fatty liver disease (NAFLD) and insulin resistance. In Wistar rats, 10 weeks of PHG treatment did not prevent HFD-induced weight gain but significantly mitigated fasting hyperglycemia, impaired insulin responses, and liver steatosis. This protective effect was not linked to hepatic lipogenesis or AMP-activated protein kinase (AMPK) activation. Instead, PHG improved mitochondrial function by reducing oxidative stress, enhancing ATP production, and increasing anti-oxidant enzyme activity. PHG also relaxed gastric smooth muscles via potassium channel activation and nitric oxide (NO) signaling, potentially delaying gastric emptying. A pilot intervention in pre-diabetic men confirmed PHG's efficacy in improving postprandial glycemic control and altering lipid metabolism. These findings suggest PHG as a potential therapeutic for NAFLD and insulin resistance, acting through mechanisms involving mitochondrial protection, anti-oxidant activity, and gastric motility modulation. Further clinical evaluation is warranted to explore PHG's full therapeutic potential.

Melatonin Alleviates Liver Mitochondrial Dysfunction in Leptin-Deficient Mice

Despite efforts to elucidate the cellular adaptations induced by obesity, cellular bioenergetics is currently considered a crucial target. New strategies to delay the onset of the hazardous adaptations induced by obesity are needed. Therefore, we evaluated the effects of 4 weeks of melatonin treatment on mitochondrial function and lipid metabolism in the livers of leptin-deficient mice. Our results revealed that the absence of leptin increased lipid storage in the liver and induced significant mitochondrial alterations, which were ultimately responsible for defective ATP production and reactive oxygen species overproduction. Moreover, leptin deficiency promoted mitochondrial biogenesis, fusion, and outer membrane permeabilization. Melatonin treatment reduced the bioenergetic deficit found in ob/ob mice, alleviating some mitochondrial alterations in the electron transport chain machinery, biogenesis, dynamics, respiration, ATP production, and mitochondrial outer membrane permeabilization. Given the role of melatonin in maintaining mitochondrial homeostasis, it could be used as a therapeutic agent against adipogenic steatosis.

Beyond the hype and toward application: liver complex in vitro models in preclinical drug safety

INTRODUCTION

Drug induced Liver-Injury (DILI) is a leading cause of drug attrition and complex in vitro models (CIVMs), including three dimensional (3D) spheroids, 3D bio printed tissues and flow-based systems, could improve preclinical prediction. Although CIVMs have demonstrated good sensitivity and specificity in DILI detection their adoption remains limited.

AREAS COVERED

This article describes DILI, the challenges with its prediction and the current strategies and models that are being used. It reviews data from industry-FDA collaborations and strategic partnerships and finishes with an outlook of CIVMs in preclinical toxicity testing. Literature searches were performed using PubMed and Google Scholar while product information was collected from manufacturer websites.

EXPERT OPINION

Liver CIVMs are promising models for predicting DILI although, a decade after their introduction, routine use by the pharmaceutical industry is limited. To accelerate their adoption, several industry-regulator-developer partnerships or consortia have been established to guide the development and qualification. Beyond this, liver CIVMs should continue evolving to capture greater immunological mimicry while partnering with computational approaches to deliver systems that change the paradigm of predicting DILI.

Tussilagone ameliorates high-fat diet-induced hepatic steatosis by enhancing energy metabolism and antioxidant activity

Non-alcoholic fatty liver disease (NAFLD) is a major health problem. However, no effective treatments are currently available. Thus, there is a critical need to develop novel drugs that can prevent and treat NAFLD with few side effects. In this study, Tussilagone (TUS), a natural sesquiterpene isolated from Tussilago farfara L, was explored in vitro and in vivo for its potential to treat NAFLD. Our results showed that in vitro TUS reduced oleic acid palmitate acid-induced triglyceride and cholesterol synthesis in HepG2cells, reduced intracellular lipid droplet accumulation, improved glucose metabolism disorders and increased energy metabolism and reduced oxidative stress levels. In vivo, TUS significantly reduced fat accumulation and improved liver injury in high-fat diet (HFD)-induced mice. TUS treatment significantly increased liver mitochondrial counts and antioxidant levels compared to the HFD group of mice. In addition, TUS was found to reduce the expression of genes involved in lipid synthesis sterol regulatory element binding protein-1 (SREBP1), fatty acid synthase (FASN), and stearoy-CoA desaturase 1 (SCD1) in vitro and in vivo. Our results suggest that TUS may be helpful in the treatment of NAFLD, suggesting that TUS is a promising compound for the treatment of NAFLD. Our findings provided novel insights into the application of TUS in regulating lipid metabolism.

Mitochondrial dynamics, quality control, and mtDNA in alcohol-associated liver disease and liver cancer

Mitochondria are intracellular organelles responsible for energy production, glucose and lipid metabolism, cell death, cell proliferation, and innate immune response. Mitochondria are highly dynamic organelles that constantly undergo fission, fusion, and intracellular trafficking, as well as degradation and biogenesis. Mitochondrial dysfunction has been implicated in a variety of chronic liver diseases including alcohol-associated liver disease, metabolic dysfunction-associated steatohepatitis, and HCC. In this review, we provide a detailed overview of mitochondrial dynamics, mitophagy, and mitochondrial DNA-mediated innate immune response, and how dysregulation of these mitochondrial processes affects the pathogenesis of alcohol-associated liver disease and HCC. Mitochondrial dynamics and mitochondrial DNA-mediated innate immune response may thereby represent an attractive therapeutic target for ameliorating alcohol-associated liver disease and alcohol-associated HCC.

Hepatic effects of acetochlor chiral isomers in zebrafish and L02 cells

The pesticide acetochlor (ACT) is a chiral isomer commonly detected in the global environment, yet its specific impacts on liver function remain poorly understood. We utilized zebrafish and L02 cells as research models to comprehensively investigate how ACT and its chiral isomers affect the liver. Our investigations unveiled that the R, Rac, and S isomers of ACT disrupt hepatic lipid transport, catabolism, and synthesis, leading to delayed yolk sac absorption and the accumulation of lipids in zebrafish embryos. These isomers induce oxidative stress in the liver of zebrafish embryos, reducing antioxidant levels and enzyme activity. The accumulated lipids in the liver render it susceptible to oxidative stress, further exacerbating hepatocyte damage. Hepatocyte damage manifests as extensive vacuolization of liver cells and alterations in liver morphology, which are induced by R, Rac, and S. Furthermore, we elucidated the molecular mechanisms underpinning the disturbance of hepatic lipid metabolism by R, Rac, and S in L02 cells. These compounds stimulate lipid synthesis through the upregulation of the AMPK/SREBP-1c/FAS pathway while inhibiting lipolysis via downregulation of the PPAR-α/CPT-1a pathway. Remarkably, our results highlight that S exhibits significantly higher hepatotoxicity in comparison to R. This study provides valuable insights into the hepatic effects of ACT chiral isomers.

The dynamic equilibrium between the protective and toxic effects of matrine in the development of liver injury: a systematic review and meta-analysis

Background: Matrine, an alkaloid derived from the dried roots of Sophora flavescens Aiton, has been utilized for the treatment of liver diseases, but its potential hepatotoxicity raises concerns. However, the precise condition and mechanism of action of matrine on the liver remain inconclusive. Therefore, the objective of this systematic review and meta-analysis is to comprehensively evaluate both the hepatoprotective and hepatotoxic effects of matrine and provide therapeutic guidance based on the findings. Methods: The meta-analysis systematically searched relevant preclinical literature up to May 2023 from eight databases, including PubMed, Web of Science, Cochrane Library, Embase, China National Knowledge Infrastructure, WanFang Med Online, China Science and Technology Journal Database, and China Biomedical Literature Service System. The CAMARADES system assessed the quality and bias of the evidence. Statistical analysis was conducted using STATA, which included the use of 3D maps and radar charts to display the effects of matrine dosage and frequency on hepatoprotection and hepatotoxicity. Results: After a thorough screening, 24 studies involving 657 rodents were selected for inclusion. The results demonstrate that matrine has bidirectional effects on ALT and AST levels, and it also regulates SOD, MDA, serum TG, serum TC, IL-6, TNF-α, and CAT levels. Based on our comprehensive three-dimensional analysis, the optimal bidirectional effective dosage of matrine ranges from 10 to 69.1 mg/kg. However, at a dose of 20-30 mg/kg/d for 0.02-0.86 weeks, it demonstrated high liver protection and low toxicity. The molecular docking analysis revealed the interaction between MT and SERCA as well as SREBP-SCAP complexes. Matrine could alter Ca2+ homeostasis in liver injury via multiple pathways, including the SREBP1c/SCAP, Notch/RBP-J/HES1, IκK/NF-κB, and Cul3/Rbx1/Keap1/Nrf2. Conclusion: Matrine has bidirectional effects on the liver at doses ranging from 10 to 69.1 mg/kg by influencing Ca2+ homeostasis in the cytoplasm, endoplasmic reticulum, Golgi apparatus, and mitochondria. Systematic review registration: https://inplasy.com/, identifier INPLASY202340114.

Endometrial organoids: a reservoir of functional mitochondria for uterine repair

Background: Asherman's syndrome (AS) is a dreadful gynecological disorder of the uterus characterized by intrauterine adhesion with severe fibrotic lesions, resulting in a damaged basalis layer with infertility. Despite extensive research on overcoming AS, evidence-based effective and reproducible treatments to improve the structural and functional morphology of the AS endometrium have not been established. Methods: Endometrial organoids generated from human or mouse endometrial tissues were transplanted into the uterine cavity of a murine model of AS to evaluate their transplantable feasibility to improve the AS uterine environment. The successful engraftment of organoid was confirmed by detection of human mitochondria and cytosol (for human endometrial organoid) or enhanced green fluorescent protein signals (for mouse endometrial organoid) in the recipient endometrium. The therapeutic effects mediated by organoid transplantation were examined by the measurements of fibrotic lesions, endometrial receptivity and angiogenesis, and fertility assessment by recording the number of implantation sites and weighing the fetuses and placenta. To explore the cellular and molecular mechanisms underlying the recovery of AS endometrium, we evaluated the status of mitochondrial movement and biogenetics in organoid transplanted endometrium. Results: Successfully engrafted endometrial organoids with similar morphological and molecular features to the parental tissues dramatically repaired the AS-induced damaged endometrium, significantly reducing fibrotic lesions and increasing fertility outcomes in mice. Moreover, dysfunctional mitochondria in damaged tissues, which we propose might be a key cellular feature of the AS endometrium, was fully recovered by functional mitochondria transferred from engrafted endometrial organoids. Endometrial organoid-originating mitochondria restored excessive collagen accumulation in fibrotic lesions and shifted uterine metabolic environment to levels observed in the normal endometrium. Conclusions: Our findings suggest that endometrial organoid-originating mitochondria might be key players to mediate uterine repair resulting in fertility enhancement by recovering abrogated metabolic circumstance of the endometrium with AS. Further studies addressing the clinical applicability of endometrial organoids may aid in identifying new therapeutic strategies for infertility in patients with AS.

Non-Genetic-Induced Zebrafish Model for Type 2 Diabetes with Emphasis on Tools in Model Validation

The unrelenting increase in the incidence of type 2 diabetes (T2D) necessitates the urgent need for effective animal models to mimic its pathophysiology. Zebrafish possess human-like metabolic traits and share significant genetic similarities, making them valuable candidates for studying metabolic disorders, including T2D. This review emphasizes the critical role of animal models in diabetes research, especially focusing on zebrafish as an alternative model organism. Different approaches to a non-genetic model of T2D in zebrafish, such as the glucose solution, diet-induced, chemical-induced, and combined diet-induced and glucose solution methods, with an emphasis on model validation using indicators of T2D, were highlighted. However, a significant drawback lies in the validation of these models. Some of these models have not extensively demonstrated persistent hyperglycemia or response to insulin resistance and glucose tolerance tests, depicted the morphology of the pancreatic β-cell, or showed their response to antidiabetic drugs. These tools are crucial in T2D pathology. Future research on non-genetic models of T2D in zebrafish must extensively focus on validating the metabolic deficits existing in the model with the same metabolic defects in humans and improve on the existing models for a better understanding of the molecular mechanisms underlying T2D and exploring potential therapeutic interventions.

Supplementation with EPA and DHA omega-3 fatty acids improves peripheral immune cell mitochondrial dysfunction and inflammation in subjects with obesity

Omega-3 fatty acids (w-3 FA) have anti-inflammatory effects and improve mitochondrial function. Nonetheless, little is known about their effect on mitochondrial bioenergetics of peripheral blood mononuclear cells (PBMCs) in individuals with obesity. Thus, this study aimed to determine the mitochondrial bioenergetics status and cell subset composition of PBMCs during obesity, before and after 1 month supplementation with w-3 FA. We performed a case-control study with twelve women with normal BMI (lean group) and 19 with grade 2 obesity (obese group), followed by a before-after prospective study where twelve subjects with obesity received a 1 month intervention with 5.25 g of w-3 FA (3.5 g eicosapentaenoic (EPA) and 1.75 g docosahexaenoic (DHA) acids), and obtained PBMCs from all participants. Mitochondrial bioenergetic markers, including basal and ATP-production associated respiration, proton leak, and nonmitochondrial respiration, were higher in PBMCs from the obese group vs. the lean group. The bioenergetic health index (BHI), a marker of mitochondrial function, was lower in the obese vs. the lean group. In addition, Th1, Th2, Th17, CD4+ Tregs, CD8+ Tregs, and Bregs, M1 monocytes and pDCreg cells were higher in PBMCs from the obese group vs. the lean group. The w-3 FA intervention improved mitochondrial function, mainly by decreasing nonmitochondrial respiration and increasing the reserve respiratory capacity and BHI. The intervention also reduced circulating pro-inflammatory and anti-inflammatory lymphocyte and monocytes subsets in individuals with obesity. The mitochondrial dysfunction of PBMCs and the higher proportion of peripheral pro-inflammatory and anti-inflammatory immune cells in subjects with obesity, improved with 1 month supplementation with EPA and DHA.

Thrap3 promotes nonalcoholic fatty liver disease by suppressing AMPK-mediated autophagy

Autophagy functions in cellular quality control and metabolic regulation. Dysregulation of autophagy is one of the major pathogenic factors contributing to the progression of nonalcoholic fatty liver disease (NAFLD). Autophagy is involved in the breakdown of intracellular lipids and the maintenance of healthy mitochondria in NAFLD. However, the mechanisms underlying autophagy dysregulation in NAFLD remain unclear. Here, we demonstrate that the hepatic expression level of Thrap3 was significantly increased in NAFLD conditions. Liver-specific Thrap3 knockout improved lipid accumulation and metabolic properties in a high-fat diet (HFD)-induced NAFLD model. Furthermore, Thrap3 deficiency enhanced autophagy and mitochondrial function. Interestingly, Thrap3 knockout increased the cytosolic translocation of AMPK from the nucleus and enhanced its activation through physical interaction. The translocation of AMPK was regulated by direct binding with AMPK and the C-terminal domain of Thrap3. Our results indicate a role for Thrap3 in NAFLD progression and suggest that Thrap3 is a potential target for NAFLD treatment.

The ER calcium channel Csg2 integrates sphingolipid metabolism with autophagy

Sphingolipids are ubiquitous components of membranes and function as bioactive lipid signaling molecules. Here, through genetic screening and lipidomics analyses, we find that the endoplasmic reticulum (ER) calcium channel Csg2 integrates sphingolipid metabolism with autophagy by regulating ER calcium homeostasis in the yeast Saccharomyces cerevisiae. Csg2 functions as a calcium release channel and maintains calcium homeostasis in the ER, which enables normal functioning of the essential sphingolipid synthase Aur1. Under starvation conditions, deletion of Csg2 causes increases in calcium levels in the ER and then disturbs Aur1 stability, leading to accumulation of the bioactive sphingolipid phytosphingosine, which specifically and completely blocks autophagy and induces loss of starvation resistance in cells. Our findings indicate that calcium homeostasis in the ER mediated by the channel Csg2 translates sphingolipid metabolism into autophagy regulation, further supporting the role of the ER as a signaling hub for calcium homeostasis, sphingolipid metabolism and autophagy.

Adipose tissue-derived exosomes contribute to obesity-associated liver diseases in long-term high-fat diet-fed mice, but not in short-term

Introduction

Our study aimed to investigate the changes in hepatic endoplasmic reticulum (ER) stress, inflammation, insulin signaling, and lipid metabolism during the administration of a high-fat diet (HFD) in mice in order to identify correlations between obesity and metabolic disease development in the liver.

Methods

We used short-, medium-, and long-term HFD periods, corresponding to 4, 8, and 12 weeks, respectively, and isolated exosomes from adipose tissue. We confirmed the effect of adipose tissue-derived exosomes on metabolic disorders in obesity in alpha mouse liver 12 (AML12) hepatocytes.

Results

Adipose tissue-derived exosomes from HFD mice did not affect the AML12 cells after 4 weeks, but ER stress, inflammatory response, insulin resistance, and lipid synthesis were observed after 8 and 12 weeks. Furthermore, we confirmed that an HFD increases the amount of adipose tissue-derived exosomes in mice. Consequently, we can infer that adipose tissue-derived exosomes from HFD-fed mice significantly increase ER stress, inflammatory response, insulin resistance, and lipid synthesis in AML12 cells.

Discussion

Our results demonstrate that obesity alters the effects of adipose tissue-derived exosomes in the liver, potentially becoming a risk factor in the development of obesity-induced liver diseases.

The Effect of Bioactive Aliment Compounds and Micronutrients on Non-Alcoholic Fatty Liver Disease

In the current review, we focused on identifying aliment compounds and micronutrients, as well as addressed promising bioactive nutrients that may interfere with NAFLD advance and ultimately affect this disease progress. In this regard, we targeted: 1. Potential bioactive nutrients that may interfere with NAFLD, specifically dark chocolate, cocoa butter, and peanut butter which may be involved in decreasing cholesterol concentrations. 2. The role of sweeteners used in coffee and other frequent beverages; in this sense, stevia has proven to be adequate for improving carbohydrate metabolism, liver steatosis, and liver fibrosis. 3. Additional compounds were shown to exert a beneficial action on NAFLD, namely glutathione, soy lecithin, silymarin, Aquamin, and cannabinoids which were shown to lower the serum concentration of triglycerides. 4. The effects of micronutrients, especially vitamins, on NAFLD. Even if most studies demonstrate the beneficial role of vitamins in this pathology, there are exceptions. 5. We provide information regarding the modulation of the activity of some enzymes related to NAFLD and their effect on this disease. We conclude that NAFLD can be prevented or improved by different factors through their involvement in the signaling, genetic, and biochemical pathways that underlie NAFLD. Therefore, exposing this vast knowledge to the public is particularly important.

Nutritional Support for Alcoholic Liver Disease

Malnutrition is a common finding in alcohol use disorders and is associated with the prognosis of patients with alcoholic liver disease (ALD). These patients also frequently show deficiencies in vitamins and trace elements, increasing the likelihood of anemia and altered cognitive status. The etiology of malnutrition in ALD patients is multifactorial and complex and includes inadequate dietary intake, abnormal absorption and digestion, increased skeletal and visceral protein catabolism, and abnormal interactions between ethanol and lipid metabolism. Most nutritional measures derive from general chronic liver disease recommendations. Recently, many patients with ALD have been diagnosed with metabolic syndrome, which requires individualized treatment via nutritional therapy to avoid overnutrition. As ALD progresses to cirrhosis, it is frequently complicated by protein–energy malnutrition and sarcopenia. Nutritional therapy is also important in the management of ascites and hepatic encephalopathy as liver failure progresses. The purpose of the review is to summarize important nutritional therapies for the treatment of ALD.

Crosstalk between Adipose Tissue and Hepatic Mitochondria in the Development of the Inflammation and Liver Injury during Ageing in High-Fat Diet Fed Rats

Obesity is considered an epidemic disorder, due to an imbalance between energy consumption and metabolizable energy intake. This balance is increasingly disrupted during normal aging processes due to the progressive impairment of mechanisms that normally control energy homeostasis. Obesity is triggered by an excessive lipid depots but reflects systemic inflammation along with large adipocytes secreting proinflammatory adipokines, an increase of the free fatty acids levels in the bloodstream, and ectopic lipid accumulation. Hepatic fat accumulation is the most common cause of chronic liver disease, characterized by mitochondrial dysfunction with a consequent impaired fat metabolism and increased oxidative stress. Therefore, mitochondrial dysfunction is associated to hepatic lipid accumulation and related complications. In this study, we assessed the crosstalk between adipose tissue and liver, analyzing the time-course of changes in hepatic mitochondrial fatty acid oxidation capacity versus fatty acid storage, focusing on the contribution of adipose tissue inflammation to hepatic lipid accumulation, using a rodent model of high fat diet-induced obesity. Our results demonstrate that both high-fat diet-induced obesity and aging induce dysregulation of adipose tissue function and similar metabolic alterations mediated by mitochondrial function impairment and altered inflammatory profile. The high fat diet-induced obesity anticipates and exacerbates liver mitochondrial dysfunction that occurs with aging processes.

[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.

Loss of hepatic DRP1 exacerbates alcoholic hepatitis by inducing megamitochondria and mitochondrial maladaptation

BACKGROUND AND AIMS

Increased megamitochondria formation and impaired mitophagy in hepatocytes have been linked to the pathogenesis of alcohol-associated liver disease (ALD). This study aims to determine the mechanisms by which alcohol consumption increases megamitochondria formation in the pathogenesis of ALD.

APPROACH AND RESULTS

Human alcoholic hepatitis (AH) liver samples were used for electron microscopy, histology, and biochemical analysis. Liver-specific dynamin-related protein 1 (DRP1; gene name DNM1L, an essential gene regulating mitochondria fission ) knockout (L-DRP1 KO) mice and wild-type mice were subjected to chronic plus binge alcohol feeding. Both human AH and alcohol-fed mice had decreased hepatic DRP1 with increased accumulation of hepatic megamitochondria. Mechanistic studies revealed that alcohol feeding decreased DRP1 by impairing transcription factor EB-mediated induction of DNM1L . L-DRP1 KO mice had increased megamitochondria and decreased mitophagy with increased liver injury and inflammation, which were further exacerbated by alcohol feeding. Seahorse flux and unbiased metabolomics analysis showed alcohol intake increased mitochondria oxygen consumption and hepatic nicotinamide adenine dinucleotide (NAD + ), acylcarnitine, and ketone levels, which were attenuated in L-DRP1 KO mice, suggesting that loss of hepatic DRP1 leads to maladaptation to alcohol-induced metabolic stress. RNA-sequencing and real-time quantitative PCR analysis revealed increased gene expression of the cGAS-stimulator of interferon genes (STING)-interferon pathway in L-DRP1 KO mice regardless of alcohol feeding. Alcohol-fed L-DRP1 KO mice had increased cytosolic mtDNA and mitochondrial dysfunction leading to increased activation of cGAS-STING-interferon signaling pathways and liver injury.

CONCLUSION

Alcohol consumption decreases hepatic DRP1 resulting in increased megamitochondria and mitochondrial maladaptation that promotes AH by mitochondria-mediated inflammation and cell injury.

Current Therapeutic Options and Potential of Mesenchymal Stem Cell Therapy for Alcoholic Liver Disease

Alcoholic liver disease (ALD) is a globally prevalent chronic liver disease caused by chronic or binge consumption of alcohol. The therapeutic efficiency of current therapies for ALD is limited, and there is no FDA-approved therapy for ALD at present. Various strategies targeting pathogenic events in the progression of ALD are being investigated in preclinical and clinical trials. Recently, mesenchymal stem cells (MSCs) have emerged as a promising candidate for ALD treatment and have been tested in several clinical trials. MSC-released factors have captured attention, as they have the same therapeutic function as MSCs. Herein, we focus on current therapeutic options, recently proposed strategies, and their limitations in ALD treatment. Also, we review the therapeutic effects of MSCs and those of MSC-related secretory factors on ALD. Although accumulating evidence suggests the therapeutic potential of MSCs and related factors in ALD, the mechanisms underlying their actions in ALD have not been well studied. Further investigations of the detailed mechanisms underlying the therapeutic role of MSCs in ALD are required to expand MSC therapies to clinical applications. This review provides information on current or possible treatments for ALD and contributes to our understanding of the development of effective and safe treatments for ALD.

CSAD Ameliorates Lipid Accumulation in High-Fat Diet-Fed Mice

Non-alcoholic fatty liver disease (NAFLD) is a chronic metabolic disease manifested in hepatic steatosis, inflammation, fibrosis, etc., which affects over one-quarter of the population around the world. Since no effective therapeutic drugs are available to cope with this widespread epidemic, the functional research of genes with altered expression during NAFLD helps understand the pathogenesis of this disease and the development of new potential therapeutic targets for drugs. In the current work, we discovered via the analysis of the Gene Expression Omnibus (GEO) dataset that cysteine sulfinic acid decarboxylase (CSAD) decreased significantly in NAFLD patients, which was also confirmed in multiple NAFLD mouse models (HFD-fed C57BL/6J, db/db and HFHFrHC-fed C57BL/6J mice). Next, CSAD's function in the progression of NAFLD was explored using AAV-mediated liver-directed gene overexpression in an HFD-fed mouse model, where the overexpression of CSAD in the liver could alleviate NAFLD-associated pathologies, including body weight, liver/body weight ratio, hepatic triglyceride and total cholesterol, and the degree of steatosis. Mechanically, we found that the overexpression of CSAD could increase the expression of some genes related to fatty acid β-oxidation (Acad1, Ppara, and Acox1). Furthermore, we also detected that CSAD could improve mitochondrial injury in vitro and in vivo. Finally, we proposed that the effect of CSAD on lipid accumulation might be independent of the taurine pathway. In conclusion, we demonstrated that CSAD is involved in the development of NAFLD as a protective factor, which suggested that CSAD has the potential to become a new target for drug discovery in NAFLD.

Mechanistic insights into the pleiotropic effects of butyrate as a potential therapeutic agent on NAFLD management: A systematic review

Non-alcoholic fatty liver disease (NAFLD) is one of the most common chronic diseases worldwide. As a multifaceted disease, NAFLD's pathogenesis is not entirely understood, but recent evidence reveals that gut microbiota plays a significant role in its progression. Butyrate, a gut microbiota metabolite, has been reported to have hepato-protective effects in NAFLD animal models. The purpose of this systematic review is to determine how butyrate affects the risk factors for NAFLD. Searches were conducted using relevant keywords in electronic databases up to March 2022. According to the evidence presented in this study, butyrate contributes to a wide variety of biological processes in the gut-liver axis. Its beneficial properties include improving intestinal homeostasis and liver health as well as anti-inflammatory, metabolism regulatory and anti-oxidative effects. These effects may be attributed to butyrate's ability to regulate gene expression as an epigenetic modulator and trigger cellular responses as a signalling molecule. However, the exact underlying mechanisms remain unclear. Human trials have not been performed on the effect of butyrate on NAFLD, so there are concerns about whether the results of animal studies can be translated to humans. This review summarises the current knowledge about the properties of butyrate, particularly its potential effects and mechanisms on liver health and NAFLD management.

Moringa oleifera Improves MAFLD by Inducing Epigenetic Modifications

Background and aims. Metabolic Associated Fatty Liver Disease (MAFLD) encompasses a spectrum of diseases from simple steatosis to nonalcoholic steatohepatitis (NASH). Here, we investigated the hepatoprotective role of Moringa oleifera aqueous extract on hepatic miRNAs, genes and protein expression, as well as histological and biochemical parameters in an experimental model of NASH. Methods. Male C57BL/6J mice were fed with a high fat diet (HFD, 60% lipids, 42 gr/L sugar in water) for 16 weeks. Moringa extract was administered via gavage during the final 8 weeks. Insulin Tolerance Test (ITT) and HOMA-IR were calculated. Serum levels of insulin, resistin, leptin and PAI-1 and hepatic expression of miR-21a-5p, miR-103-3p, miR-122-5p, miR-34a-5p and SIRT1, AMPKα and SREBP1c protein were evaluated. Alpha-SMA immunohistochemistry and hematoxylin-eosin, Masson’s trichrome and sirius red staining were made. Hepatic transcriptome was analyzed using microarrays. Results. Animals treated with Moringa extract improved ITT and decreased SREBP1c hepatic protein, while SIRT1 increased. Hepatic expression of miR-21a-5p, miR-103-3p and miR-122-5p, miR34a-5p was downregulated. Hepatic histologic analysis showed in Moringa group (HF + MO) a significant decrease in inflammatory nodules, macro steatosis, fibrosis, collagen and αSMA reactivity. Analysis of hepatic transcriptome showed down expression of mRNAs implicated in DNA response to damage, endoplasmic reticulum stress, lipid biosynthesis and insulin resistance. Moringa reduced insulin resistance, de novo lipogenesis, hepatic inflammation and ER stress. Conclusions. Moringa prevented progression of liver damage in a model of NASH and improved biochemical, histological and hepatic expression of genes and miRNAs implicated in MAFLD/NASH development.

Whey protein protects liver mitochondrial function against oxidative stress in rats exposed to acrolein

Acrolein (AC) is one of the most toxic environmental pollutants, often associated with incomplete combustion of petrol, wood, and plastic, oil frying, and tobacco smoking, that causes oxidative damage to DNA and mitochondria. Considering that little is known about the protective effects of whey protein (WP) against AC-induced liver toxicity, the aim of our study was to learn more about them in respect to liver mitochondrial oxidative stress, respiratory enzymes, Krebs cycle enzymes, and adenosine triphosphate (ATP). To do that, we treated Sprague Dawley rats with daily doses of AC alone (5 mg/kg bw in 0.9 % NaCl solution), WP alone (200 mg/kg bw, in 0.9 % NaCl solution), or their combination by oral gavage for six days a week over 30 days. As expected, the AC group showed a drop in glutathione levels and antioxidant, transport chain, and tricarboxylic acid cycle enzyme activities and a significant rise in mitochondrial lipid peroxidation and protein carbonyl levels. Co-treatment with WP mitigated oxidative stress and improved enzyme activities. Judging by the measured parameters, WP reduced AC toxicity by improving bioenergetic mechanisms and eliminating oxidative stress.

Insulin resistance enhances binge ethanol-induced liver injury through promoting oxidative stress and up-regulation CYP2E1

Alcoholic liver disease (ALD) has caused a serious burden on public and personal health in crowd with ethanol abuse. The effects of insulin resistance (IR) on ALD and the mechanisms underlying these responses are still not well understood. In this study, we investigated the changes of liver injury, inflammation, apoptosis, mitochondrial dysfunction and CYP2E1 changes in liver of mice exposed to ethanol with IR or not. We found IR increased the sensitivity of liver injury in mice exposed to ethanol, manifested as the increase serum activities of AST and ALT, the accumulation of triglycerides, the deterioration of liver pathology and increase of inflammatory factors. IR also exacerbated apoptosis and mitochondrial dysfunction in liver of mice exposed to ethanol. The increase of oxidative stress and the decrease of antioxidant defense ability might be responsible for the sensitizing effects of IR on ethanol-induced liver injury, supported by the increase of MDA levels and the decline of GSH/GSSG, the inactivation of antioxidant enzymes SOD, GR through the inhibition of Nrf-2 pathway. The activation of CYP2E1 might be also involved in the sensitizing effects of IR on ethanol induced liver injury in mice. These results demonstrated that IR exhibited a significant pro-oxidative and pro-apoptosis effects to aggravate alcoholic liver injury. Our study helped us to better understand the sensitive role of IR on ALD and suggested that alcohol intake may be more harmful for people with IR.

Suppression of colonic oxidative stress caused by chronic ethanol administration and attenuation of ethanol-induced colitis and gut leakiness by oral administration of sesaminol in mice

Chronic consumption of excess ethanol is one of the major risk factors for colorectal cancer (CRC), and the pathogenesis of ethanol-related CRC (ER-CRC) involves ethanol-induced oxidative-stress and inflammation in the colon and rectum, as well as gut leakiness. In this study, we hypothesised that oral administration of sesaminol, a sesame lignan, lowers the risk of ER-CRC because we found that it is a strong antioxidant with very low prooxidant activity. This hypothesis was examined using a mouse model, in which 2.0% v/v ethanol was administered ad libitum for 2 weeks with or without oral gavage with sesaminol (2.5 mg per day). Oral sesaminol administration suppressed the ethanol-induced colonic lesions and the ethanol-induced elevation of the colonic levels of oxidative stress markers (8-hydroxy-2'-deoxyguanosine, malondialdehyde, and 4-hydroxyalkenals). It consistently suppressed the chronic ethanol-induced expressions of cytochrome P450-2E1 and inducible nitric oxide synthase and upregulated heme oxygenase-1 expression, probably via the nuclear factor erythroid-derived 2-like 2 pathway in the mouse colon. Oral sesaminol administration also suppressed the chronic ethanol-induced elevation of colonic inflammation marker levels, such as those of tumour necrosis factor-α, interleukin-6, and monocyte chemoattractant protein-1, probably via the nuclear factor-kappa B pathway. Moreover, it prevented the chronic ethanol-induced gut leakiness by restoring tight junction proteins, giving rise to lower plasma endotoxin levels compared with those of ethanol-administered mice. All of these results suggest that dietary supplementation of sesaminol may lower the risk of ER-CRC by suppressing each of the above-mentioned steps in ER-CRC pathogenesis.

Fu brick tea alleviates alcoholic liver injury by modulating the gut microbiota-liver axis and inhibiting the hepatic TLR4/NF-κB signaling pathway

This study first evaluated the protective effects of Fu brick tea water extracts (FTE) on alcoholic liver injury and its underlying mechanism in C57BL/6J mice. Oral administration of FTE by oral gavage (400 mg per kg bw) for 12 weeks significantly alleviated lipid metabolism disorder, reduced the activities of serum ALT and AST, decreased the expression of the liver CYP2E1 gene, and enhanced the antioxidant capacities of the livers in alcohol-fed mice (p < 0.05). FTE also relieved alcohol-induced gut microbiota dysbiosis by promoting the proliferation of probiotics such as Muribaculaceae and Lactobacillus, and subsequently increased the cecal levels of short-chain fatty acids (SCFAs) and decreased the tryptophan content of alcohol-fed mice (p < 0.05). Importantly, FTE was found to improve the alcohol-impaired gut barrier function by up-regulating the expression of the epithelial tight junction protein. Accordingly, FTE decreased the circulating lipopolysaccharide (LPS) and thus inhibited the hepatic TLR4/NF-κB signaling pathway to ameliorate alcoholic liver injury. Cumulatively, these findings shed light on the important role of the gut microbiota-liver axis behind the protective efficacy of FTE on alcoholic liver injury.

Anthocyanin-Rich Extract of Red Cabbage Attenuates Advanced Alcohol Hepatotoxicity in Rats in Association with Mitochondrial Activity Modulation

Aim

The liver is the main target for alcohol-induced injury. The aims of this work were to carry out further research into the mechanisms of liver damage induced by long-term administration of high-dose ethanol to rats and to evaluate the hepatoprotective potential of red cabbage (Brassica oleracea var. capitata f. rubra) anthocyanins (RCE).

Material/Methods

Male albino Wistar rats were divided into four groups. Group 1 was the control. Groups 2 through 4 received ethanol (4 g/kg body weight, 8 weeks). Group 3 received 11 mg RCE/kg and Group 4 received 22 mg RCE/kg. Dry lyophilised RCE was prepared from fresh red cabbage and analysed. We then evaluated the liver histology, mitochondrial respiration, and biochemical and immunological parameters in these groups of rats.

Results

The rat intoxication caused steatohepatitis characterised by macro- and microvesicular steatosis, ballooning and fatty liver dystrophies, lymphocytic infiltration, neutral lipid accumulation, and elevations of the serum activities of the liver injury marker enzymes. The treatment of alcohol-administered rats with RCE (mainly, cyanidin-3-diglucoside-5-glucoside, cyanidin-3-coumaroylrutinoside-5-hexoside, cyanidin-3-feruloylrutinoside-5-hexoside, delphinidin-3-feruloylrutinoside-hexoside) dose-dependently alleviated these pathological changes: The sizes of hepatocyte lipid vacuoles and the inflammatory signs were decreased, and the levels of the rat serum biochemical markers of liver injury, proinflammatory cytokines TNFα and IL-6, and the adipokine leptin (and not TGFβ) were significantly reversed. The RCE administration during intoxication completely recovered the changed liver mitochondria respiration rates and the ADP/O coefficient, as well as the phagocytic index and neutrophil metabolic activity in the blood. In experiments in vitro, RCE (13.6 μg/ml) modulated the respiratory parameters of isolated rat liver mitochondria, dissipated mitochondrial membrane potential, and inhibited the Ca2+-induced mitochondrial permeability transition.

Conclusion

The red cabbage anthocyanins could be useful for treatment of alcoholic liver injury due to their Ca2+-ionophoric/protonophoric activity, influence on Ca2+ homeostasis, and improving mitochondrial functions and inflammatory status.

Mesenchymal stem cells-based therapy in liver diseases

Multiple immune cells and their products in the liver together form a complex and unique immune microenvironment, and preclinical models have demonstrated the importance of imbalances in the hepatic immune microenvironment in liver inflammatory diseases and immunocompromised liver diseases. Various immunotherapies have been attempted to modulate the hepatic immune microenvironment for the purpose of treating liver diseases. Mesenchymal stem cells (MSCs) have a comprehensive and plastic immunomodulatory capacity. On the one hand, they have been tried for the treatment of inflammatory liver diseases because of their excellent immunosuppressive capacity; On the other hand, MSCs have immune-enhancing properties in immunocompromised settings and can be modified into cellular carriers for targeted transport of immune enhancers by genetic modification, physical and chemical loading, and thus they are also used in the treatment of immunocompromised liver diseases such as chronic viral infections and hepatocellular carcinoma. In this review, we discuss the immunological basis and recent strategies of MSCs for the treatment of the aforementioned liver diseases. Specifically, we update the immune microenvironment of the liver and summarize the distinct mechanisms of immune microenvironment imbalance in inflammatory diseases and immunocompromised liver diseases, and how MSCs can fully exploit their immunotherapeutic role in liver diseases with both immune imbalance patterns.

Dietary Supplementation of Salidroside Alleviates Liver Lipid Metabolism Disorder and Inflammatory Response to Promote Hepatocyte Regeneration via PI3K/AKT/Gsk3-β Pathway

Fatty liver hemorrhagic syndrome (FLHS) is a chronic hepatic disease which occurs when there is a disorder in lipid metabolism. FLHS is often observed in caged laying hens and characterized by a decrease in egg production and dramatic increase of mortality. Salidroside (SDS) is an herbal drug which has shown numerous pharmacological activities, such as protecting mitochondrial function, attenuating cell apoptosis and inflammation, and promoting antioxidant defense system. We aimed to determine the therapeutic effects of SDS on FLHS in laying hens and investigate the underlying mechanisms through which SDS operates these functions. We constructed oleic acid (OA)-induced fatty liver model in vitro and high-fat diet-induced FLHS of laying hens in vivo. The results indicated that SDS inhibited OA-induced lipid accumulation in chicken primary hepatocytes, increased hepatocyte activity, elevated the mRNA expression of proliferation related genes PCNA, CDK2, and cyclinD1 and increased the protein levels of PCNA and CDK2 (P < 0.05), as well as decreased the cleavage levels of Caspase-9, Caspase-8, and Caspase-3 and apoptosis in hepatocytes (P < 0.05). Moreover, SDS promoted the phosphorylation levels of PDK1, AKT, and Gsk3-β, while inhibited the PI3K inhibitor (P < 0.05). Additionally, we found that high-fat diet-induced FLHS hens had heavier body weight, liver weight, and abdominal fat weight, and severe steatosis in histology, compared with the control group (Con). However, hens fed with SDS maintained lighter body weight, liver weight, and abdominal fat weight, as well as normal liver without hepatic steatosis. In addition, high-fat diet-induced FLHS hens had high levels of serum total cholesterol (TC), triglyceride (TG), alanine transaminase (ALT), and aspartate aminotransferase (AST) compared to the Con group, however, in the Model+SDS group, the levels of TC, TG, ALT, and AST decreased significantly, whereas the level of superoxide dismutase (SOD) increased significantly (P < 0.05). We also found that SDS significantly decreased the mRNA expression abundance of PPARγ, SCD, and FAS in the liver, as well as increased levels of PPARα and MTTP, and decreased the mRNA expression of TNF-α, IL-1β, IL-6, and IL-8 in the Model+SDS group (P < 0.05). In summary, this study showed that 0.3 mg/mL SDS attenuated ROS generation, inhibited lipid accumulation and hepatocyte apoptosis, and promoted hepatocyte proliferation by targeting the PI3K/AKT/Gsk3-β pathway in OA-induced fatty liver model in vitro, and 20 mg/kg SDS alleviated high-fat-diet-induced hepatic steatosis, oxidative stress, and inflammatory response in laying hens in vivo.

Hydroxytyrosol Promotes the Mitochondrial Function through Activating Mitophagy

Emerging evidence suggests that mitochondrial dysfunction mediates the pathogenesis for non-alcoholic fatty liver disease (NAFLD). Hydroxytyrosol (HT) is a key component of extra virgin olive oil which can exert beneficial effects on NAFLD through modulating mitochondria. However, the mechanism of the impacts of HT still remains elusive. Thus, an in vivo and a series of in vitro experiments were carried out to examine the impacts of hydroxytyrosol (HT) on lipid metabolism and mitochondrial function in fish. For the in vivo experiment, two diets were produced to contain 10% and 16% fat as normal-fat and high-fat diets (NFD and HFD) and two additional diets were prepared by supplementing 200 mg/kg of HT to the NFD and HFD. The test diets were fed to triplicate groups of spotted seabass (Lateolabrax maculatus) juveniles for 8 weeks. The results showed that feeding HFD leads to increased fat deposition in the liver and induces oxidative stress, both of which were ameliorated by HT application. Furthermore, transmission electron microscopy revealed that HFD destroyed mitochondrial cristae and matrix and induced severe hydropic phenotype, while HT administration relieved these alterations. The results of in vitro studies using zebrafish liver cell line (ZFL) showed that HT promotes mitochondrial function and activates PINK1-mediated mitophagy. These beneficial effects of HT disappeared when the cells were treated with cyclosporin A (Csa) as a mitophagy inhibitor. Moreover, the PINK1-mediated mitophagy activation by HT was blocked when compound C (CC) was used as an AMPK inhibitor. In conclusion, our findings demonstrated that HT alleviates fat accumulation, oxidative stress and mitochondrial dysfunction, and its effects are deemed to be mediated via activating mitophagy through the AMPK/PINK1 pathway.

Magnesium isoglycyrrhizinate attenuates acute alcohol-induced hepatic steatosis in a zebrafish model by regulating lipid metabolism and ER stress

Background

Alcoholism is a well-known risk factor for liver injury and is one of the major causes of hepatic steatosis worldwide. Although many drugs have been reported to have protective effects against acute alcohol-induced hepatotoxicity, there is limited available treatment for alcoholic liver disease (ALD), indicating an urgent need for effective therapeutic options. Herein, we first reported the protective effects of magnesium isoglycyrrhizinate (MgIG) on acute alcohol-induced hepatic steatosis and its related mechanisms in a zebrafish model.

Methods

Alcohol was administered directly to embryo medium at 5 days post-fertilization (dpf) for up to 32 h. MgIG was given to the larvae 2 h before the administration of alcohol and then cotreated with alcohol starting at 5 dpf. Oil red O staining was used to determine the incidence of steatosis, and pathological features of the liver were assessed by hematoxylin–eosin staining. Biological indexes, total cholesterol (TC) and triacylglycerol (TG) were detected in the livers of zebrafish larvae. Morphological changes in the livers of zebrafish larvae were observed using liver-specific EGFP transgenic zebrafish (Tg(lfabp10a:eGFP)). The expression levels of critical molecules related to endoplasmic reticulum (ER) stress and lipid metabolism were detected by qRT–PCR, whole-mount in situ hybridization and western blotting.

Results

Alcohol-treated larvae developed hepatomegaly and steatosis after 32 h of exposure. We found that MgIG improved hepatomegaly and reduced the incidence of steatosis in a dose-dependent manner by oil red O staining and diminished deposits of alcohol-induced fat droplets by histologic analysis. Moreover, MgIG significantly decreased the levels of TC and TG in the livers of zebrafish larvae. Furthermore, the expression levels of critical genes involved in ER stress (atf6, irela, bip, chop) and the key enzymes regulating lipid metabolism (acc1, fasn, hmgcs1 and hmgcra) were significantly higher in the alcohol-treated group than in the control group. However, in the MgIG plus alcohol-treated group, the expression of these genes was markedly decreased compared with that in the alcohol-treated group. Whole-mount in situ hybridization and western blotting also showed that MgIG had an effect on the expression levels of critical genes and proteins involved in lipid metabolism and ER stress. Our results revealed that MgIG could markedly regulate these genes and protect the liver from ER stress and lipid metabolism disorders.

Conclusions

Our study is the first to demonstrate that MgIG could protect the liver from acute alcohol stimulation by ameliorating the disorder of lipid metabolism and regulating ER stress in zebrafish larvae.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12986-022-00655-7.

Hepatoprotective effects of sea cucumber ether-phospholipids against alcohol-induced lipid metabolic dysregulation and oxidative stress in mice

Sea cucumber is widely consumed as food and folk medicine in Asia, and its phospholipids are rich sources of dietary eicosapentaenoic acid enriched ether-phospholipids (ether-PLs). Emerging evidence suggests that ether-PLs are associated with neurodegenerative disease and steatohepatitis. However, the function and mechanism of ether-PLs in alcoholic liver disease (ALD) are not well understood. To this end, the present study sought to investigate the hepatoprotective effects of sea cucumber ether-PLs, including plasmenyl phosphatidylethanolamine (PlsEtn) and plasmanyl phosphatidylcholine (PlsCho), and their underlying mechanisms. Our results showed that compared with EtOH-induced mice, ether-PL treated mice showed improved liver histology, decreased serum ALT and AST levels, and reduced alcohol metabolic enzyme (ALDH2 and ADH1) expressions. Mechanistic studies showed that ether-PLs attenuated "first-hit" hepatic steatosis and lipid accumulation evoked by alcohol administration. Moreover, PlsEtn more effectively restored endogenous plasmalogen levels than PlsCho, thereby enhancing hepatic antioxidation against "second-hit" reactive oxygen species (ROS) due to the damaged mitochondria and abnormal ethanol metabolism. Taken together, sea cucumber ether-PLs show great potential to become a natural functional food against chronic alcohol-induced hepatic steatosis and lipid metabolic dysregulation.

Blueberry-derived exosomes-like nanoparticles ameliorate nonalcoholic fatty liver disease by attenuating mitochondrial oxidative stress

Accumulating evidence indicates that mitochondrial dysfunction and oxidative stress play a pivotal role in the initiation and progression of nonalcoholic fatty liver disease (NAFLD). In this study, we found that blueberry-derived exosomes-like nanoparticles (BELNs) could ameliorate oxidative stress in rotenone-induced HepG2 cells and high-fat diet (HFD)-fed C57BL/6 mice. Preincubation with BELNs decreased the level of reactive oxygen species (ROS), increased the mitochondrial membrane potential, and prevented cell apoptosis by inducing the expression of Bcl-2 and heme oxygenase-1 (HO-1) and decreasing the content of Bax in rotenone-treated HepG2 cells. We also found that preincubation with BELNs accelerated the translocation of Nrf2, an important transcription factor of antioxidative proteins, from the cytoplasm to the nucleus in rotenone-treated HepG2 cells. Moreover, administration of BELNs improved insulin resistance, ameliorated the dysfunction of hepatocytes, and regulated the expression of detoxifying/antioxidant genes by affecting the distribution of Nrf2 in the cytoplasm and nucleus of hepatocytes of HFD-fed mice. Furthermore, BELNs supplementation prevented the formation of vacuoles and attenuated the accumulation of lipid droplets by inhibiting the expression of fatty acid synthase (FAS) and acetyl-CoA carboxylase 1 (ACC1), the two key transcription factors for de novo lipogenesis in the liver of HFD-fed mice. These findings suggested that BELNs can be used for the treatment of NAFLD because of their antioxidative activity.

Mitochondrial oxidative stress mediated Fe-induced ferroptosis via the NRF2-ARE pathway

Ferroptosis is a regulated form of cell death induced by iron (Fe)-dependent lipid peroxidation. At present, the underlying molecular mechanisms remain elusive. Herein, we hypothesized that mitochondria and the NRF2 (transcription factor nuclear factor E2-related factor 2) are potential mediators of ferroptosis, considering their well-established involvement in the oxidative stress pathway. We found that a high iron diet increased hepatic iron content and promoted glutathione (GSH) depletion, lipid peroxidation and oxidative stress. Dietary iron overload also decreased mRNA and protein expression levels of glutathione peroxidase 4 (GPX4) and cystine-glutamate antiporter (SLC7A11), and increased mRNA and protein expression of acyl-CoA synthetase long-chain family member 4 (ACSL4), which are all markers of ferroptosis. Consistent with ferroptosis, iron overload promoted lipid peroxidation and the generation of mitochondrial reactive oxygen species (ROS), and decreased the mitochondrial membrane potential (MMP). Pre-treatment with deferoxamine mesylate (DFO, an iron chelator) alleviated ROS generation and lipid peroxidation, indicating a causative link between iron overload and lipid peroxidation. Suppression of mitochondrial oxidative stress attenuated ferroptosis. Experiments with HEK293T cells revealed that Fe-induced ferroptosis involved direct inhibition of NRF2 binding to antioxidant response elements (AREs) within the promoters of the gpx4 and slc7a11 genes, which in turn induced transcriptional silencing. In conclusion, our study provided a direct link between mitochondrial oxidative stress and ferroptosis via the NRF2-ARE pathway.

Dichloroacetate reactivates pyruvate-supported peroxide removal by liver mitochondria and prevents NAFLD aggravation in NAD(P)+ transhydrogenase-null mice consuming a high-fat diet

The mechanisms by which a high-fat diet (HFD) promotes non-alcoholic fatty liver disease (NAFLD) appear to involve liver mitochondrial dysfunction and redox imbalance. The functional loss of the enzyme NAD(P)+ transhydrogenase, a main source of mitochondrial NADPH, results in impaired mitochondrial peroxide removal, pyruvate dehydrogenase inhibition by phosphorylation, and progression of NAFLD in HFD-fed mice. The present study aimed to investigate whether pharmacological reactivation of pyruvate dehydrogenase by dichloroacetate attenuates the mitochondrial redox dysfunction and the development of NAFLD in NAD(P)+ transhydrogenase-null (Nnt-/-) mice fed an HFD (60% of total calories from fat). For this purpose, Nnt-/- mice and their congenic controls (Nnt+/+) were fed chow or an HFD for 20 weeks and received sodium dichloroacetate or NaCl in the final 12 weeks via drinking water. The results showed that HFD reduced the ability of isolated liver mitochondria from Nnt-/- mice to remove peroxide, which was prevented by the dichloroacetate treatment. HFD-fed mice of both Nnt genotypes exhibited increased body and liver mass, as well as a higher content of hepatic triglycerides, but dichloroacetate treatment attenuated these abnormalities only in Nnt-/- mice. Notably, dichloroacetate treatment decreased liver pyruvate dehydrogenase phosphorylation levels and prevented the aggravation of NAFLD in HFD-fed Nnt-/- mice. Conversely, dichloroacetate treatment elicited moderate hepatocyte ballooning in chow-fed mice, suggesting potentially toxic effects. We conclude that the protection against HFD-induced NAFLD by dichloroacetate is associated with its role in reactivating pyruvate dehydrogenase and reestablishing the pyruvate-supported liver mitochondrial capacity to handle peroxide in Nnt-/- mice.

Oxidative Stress in Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a challenging disease caused by multiple factors, which may partly explain why it still remains an orphan of adequate therapies. This review highlights the interaction between oxidative stress (OS) and disturbed lipid metabolism. Several reactive oxygen species generators, including those produced in the gastrointestinal tract, contribute to the lipotoxic hepatic (and extrahepatic) damage by fatty acids and a great variety of their biologically active metabolites in a “multiple parallel-hit model”. This leads to inflammation and fibrogenesis and contributes to NAFLD progression. The alterations of the oxidant/antioxidant balance affect also metabolism-related organelles, leading to lipid peroxidation, mitochondrial dysfunction, and endoplasmic reticulum stress. This OS-induced damage is at least partially counteracted by the physiological antioxidant response. Therefore, modulation of this defense system emerges as an interesting target to prevent NAFLD development and progression. For instance, probiotics, prebiotics, diet, and fecal microbiota transplantation represent new therapeutic approaches targeting the gut microbiota dysbiosis. The OS and its counter-regulation are under the influence of individual genetic and epigenetic factors as well. In the near future, precision medicine taking into consideration genetic or environmental epigenetic risk factors, coupled with new OS biomarkers, will likely assist in noninvasive diagnosis and monitoring of NAFLD progression and in further personalizing treatments.

Alcoholic liver disease-from steatosis to cirrhosis - a biochemistry approach

Nowadays, chronic alcoholism and its health implications represent a global concern. Over three million deaths are linked to chronic alcohol intake every year. This article aims to spread awareness about the negative impact ethanol can have on almost every organ in the body, especially the liver. Understanding ethanol metabolism and the cellular pathways through which alcohol increases liver oxidative stress may prevent a broad spectrum of hepatic lesions such as steatosis, steatohepatitis, and, ultimately, cirrhosis. After a short review of ethanol metabolism and liver oxidative stress, each hepatic lesion will be individually discussed regarding the mechanism of apparition, treatment, and future targeted therapies.

Pancreastatin induces hepatic steatosis in type 2 diabetes by impeding mitochondrial functioning

AIMS

Mitochondrial dysfunction is among the key factors for the advancement of hepatic steatosis to NAFLD and NASH. Pancreastatin (PST: human ChgA250-301) is a dysglycemic hormone, previously reported to promote steatosis and inflammation in various animal models of metabolic disorders. Recently, we observed PST deregulates energy expenditure and mitochondrial functioning in perimenopausal rats. In the current study, we aimed to decipher the role of PST instigated altered mitochondrial functioning in hepatic steatosis.

MAIN METHODS

The HepG2 cells were PST exposed and the Chga gene was knocked down using siRNA and lipofectamine. Parallelly, type 2 diabetes (T2D) was developed in C57BL/6 mice by HFD feeding and administered PST inhibitor (PSTi8).

KEY FINDINGS

The PST exposed cells and HFD fed mice depicted: enhanced CHGA expression detected by IF/IHC, WB, and ELISA; dysregulated cellular ROS, mitochondrial ROS, oxygen consumption rate, mitochondrial membrane potential, ATP level, and NADP/NADP ratio; enhanced apoptosis determined by MTT, TUNEL, Annexin-V FITC, and WB of Bax/bcl2 and caspase 3; hepatic lipid accumulation upon Nile Red, Oil Red O, H&E staining, and the expression of SREBP-1c, FAS, ACC, and SCD; inflammation based on expression and circulatory level of IL6, IL-1β, and TNF-α. However, Chga knocked down HepG2 cells and PSTi8 treated mice unveiled protection from all the above abnormalities.

SIGNIFICANCE

Collectively, the aforementioned data suggested the alteration in mitochondrial function induced by PST is responsible for hepatic steatosis in T2D.