Mutual interaction between endoplasmic reticulum and mitochondria in nonalcoholic fatty liver disease

A multidisciplinary approach to the antioxidant and hepatoprotective activities of Arbutus pavarii Pampan fruit; in vitro and in Vivo biological evaluations, and in silico investigations

The Libyan Strawberry, Arbutus pavarii Pampan (ARB), is an endemic Jebel Akhdar plant used for traditional medicine. This study presents the antioxidant and hepatoprotective properties of ARB fruit-extract. ARB phytochemical analysis indicated the presence of 354.54 GAE and 36.2 RE of the phenolics and flavonoids. LC-MS analysis identified 35 compounds belonging to phenolic acids, procyanidins, and flavonoid glycosides. Gallic acid, procyanidin dimer B3, β-type procyanidin trimer C, and quercetin-3-O-glucoside were the major constituents of the plant extract. ARB administration to paracetamol (PAR)-intoxicated rats reduced serum ALT, AST, bilirubin, hepatic tissue MDA and proinflammatory markers; TNF-α and IL-6 with an increase in tissue GSH level and SOD activity. Histological and immunohistochemical studies revealed that ARB restored the liver histology and significantly reduced the tissue expression of caspase 3, IL-1B, and NF-KB in PAR-induced liver damage. Docking analysis disclosed good binding affinities of some compounds with XO, COX-1, 5-LOX, and PI3K.

Patchouli alcohol alleviates metabolic dysfunction-associated steatohepatitis via inhibiting mitochondria-associated endoplasmic reticulum membrane disruption-induced hepatic steatosis and inflammation in rats

Metabolic dysfunction-associated steatohepatitis (MASH) is a severe metabolic dysfunction-associated steatotic liver disease (MASLD) characterized by abnormal hepatic steatosis and inflammation. Previous studies have shown that Patchouli alcohol (PA), the primary component of Pogostemonis Herba, can alleviate digestive system diseases. However, its protection against MASH remains unclear. This study explored the protective effects and underlying mechanism of PA against high-fat diet-induced MASH in rats. Results showed that PA considerably reduced body weight, epididymal fat, and liver index and attenuated liver histological injury in MASH rats. PA alleviated hepatic injury by inhibiting steatosis and inflammation. These effects are associated with the improvement of SREBP-1c- and PPARα-mediated lipid metabolism and inhibition of the STING-signaling pathway-mediated inflammatory response. Moreover, PA-inhibited hepatic endoplasmic reticulum (ER) stress and mitochondrial dysfunction, reducing SREBP-1c and STING expressions and enhance PPARα expression. PA treatment had the strongest effect on the regulation of mitogen fusion protein 2 (Mfn2) in inhibiting mitochondrial dysfunction. Mfn2 is an important structural protein for binding ERs and mitochondria to form mitochondria-associated ER membranes (MAMs). MASH-mediated disruption of MAMs was inhibited after PA treatment-induced Mfn2 activation. Therefore, the pharmacological effect of PA on MASH is mainly attributed to the inhibition of MAM disruption-induced hepatic steatosis and inflammation. The findings of this study may have implications for MASH treatment that do not neglect the role of Mfn2-mediated MAMs.

MICOS Complex Loss Governs Age-Associated Murine Mitochondrial Architecture and Metabolism in the Liver, While Sam50 Dictates Diet Changes

The liver, the largest internal organ and a metabolic hub, undergoes significant declines due to aging, affecting mitochondrial function and increasing the risk of systemic liver diseases. How the mitochondrial three-dimensional (3D) structure changes in the liver across aging, and the biological mechanisms regulating such changes confers remain unclear. In this study, we employed Serial Block Face-Scanning Electron Microscopy (SBF-SEM) to achieve high-resolution 3D reconstructions of murine liver mitochondria to observe diverse phenotypes and structural alterations that occur with age, marked by a reduction in size and complexity. We also show concomitant metabolomic and lipidomic changes in aged samples. Aged human samples reflected altered disease risk. To find potential regulators of this change, we examined the Mitochondrial Contact Site and Cristae Organizing System (MICOS) complex, which plays a crucial role in maintaining mitochondrial architecture. We observe that the MICOS complex is lost during aging, but not Sam50. Sam50 is a component of the sorting and assembly machinery (SAM) complex that acts in tandem with the MICOS complex to modulate cristae morphology. In murine models subjected to a high-fat diet, there is a marked depletion of the mitochondrial protein SAM50. This reduction in Sam50 expression may heighten the susceptibility to liver disease, as our human biobank studies corroborate that Sam50 plays a genetically regulated role in the predisposition to multiple liver diseases. We further show that changes in mitochondrial calcium dysregulation and oxidative stress accompany the disruption of the MICOS complex. Together, we establish that a decrease in mitochondrial complexity and dysregulated metabolism occur with murine liver aging. While these changes are partially be regulated by age-related loss of the MICOS complex, the confluence of a murine high-fat diet can also cause loss of Sam50, which contributes to liver diseases. In summary, our study reveals potential regulators that affect age-related changes in mitochondrial structure and metabolism, which can be targeted in future therapeutic techniques.

Exploring the therapeutic effects of sulforaphane: an in-depth review on endoplasmic reticulum stress modulation across different disease contexts

The endoplasmic reticulum (ER) is an intracellular organelle that contributes to the folding of proteins and calcium homeostasis. Numerous elements can disrupt its function, leading to the accumulation of proteins that are unfolded or misfolded in the lumen of the ER, a condition that is known as ER stress. This phenomenon can trigger cell death through the activation of apoptosis and inflammation. Glucoraphanin (GRA) is the predominant glucosinolate found in cruciferous vegetables. Various mechanical and biochemical processes activate the enzyme myrosinase, leading to the hydrolysis of glucoraphanin into the bioactive compound sulforaphane. Sulforaphane is an organosulfur compound that belongs to the isothiocyanate group. It possesses a wide range of activities and has shown remarkable potential as an anti-inflammatory, antioxidant, antitumor, and anti-angiogenic substance. Additionally, sulforaphane is resistant to oxidation, has been demonstrated to have low toxicity, and is considered well-tolerable in individuals. These properties make it a valuable natural dietary supplement for research purposes. Sulforaphane has been demonstrated as a potential candidate drug molecule for managing a range of diseases, primarily because of its potent antioxidant, anti-inflammatory, and anti-apoptotic properties, which can be mediated by modulation of ER stress pathways. This review seeks to cover a wealth of data supporting the broad range of protective functions of sulforaphane, improving various diseases, such as cardiovascular, central nervous system, liver, eye, and reproductive diseases, as well as diabetes, cancer, gastroenteritis, and osteoarthritis, through the amelioration of ER stress in both in vivo and in vitro studies.

Construction of a prognostic risk model for Stomach adenocarcinoma based on endoplasmic reticulum stress genes

OBJECTIVE

Stomach adenocarcinoma (STAD) is caused by malignant transformation of gastric glandular cells and is characterized by a high incidence rate and a poor prognosis. This study was designed to establish a prognostic risk model for STAD according to endoplasmic reticulum (ER) stress feature genes as cancer cells are susceptible to ER stress.

METHODS

The TCGA-STAD dataset was downloaded to screen differentially expressed genes (DEGs). By intersecting DEGs with ER stress genes retrieved from GeneCards, ER stress-related DEGs in STAD were obtained. Kmeans cluster analysis of STAD subtypes and Single sample gene set enrichment analysis (ssGSEA) analysis of immune infiltration were performed. Cox regression analysis was utilized to construct a risk prognostic model. Samples were split into high-risk and low-risk groups according to the median risk score. Survival analysis and Receiver Operating Characteristic (ROC) curves were conducted to assess the validity of the model. Gene set enrichment analysis (GSEA) was performed to investigate differential pathways in the two risk groups. Cox analysis was performed to verify the independence of the risk model, and a nomogram was generated.

RESULTS

A total of 162 ER stress-related DEGs in STAD were identified by bioinformatics analysis. Kmeans cluster analysis showed that STAD was divided into 3 subgroups. The ssGSEA showed that the levels of immune infiltration in subgroups 2 and 3 were significantly higher than subgroup 1. With 12 prognostic genes (MATN3, ATP2A1, NOX4, AQP11, HP, CAV1, STARD3, FKBP10, EGF, F2, SERPINE1, CNGA3) selected from ER stress-related DEGs using Cox regression analysis, we then constructed a prognostic model. Kaplan-Meier (K‑M) survival curves and ROC curves showed good prediction performance of the model. Significant enrichment of genes in the high-risk group was found in extracellular matrix (ECM) receptor interaction. Cox regression analysis combined with clinical factors showed that the risk model could be used as an independent prognostic factor. The prediction correction curve showed that the good prediction ability of the nomogram.

CONCLUSION

The STAD could be divided into three subgroups, and the 12-gene model constructed by ER stress signatures had a good prognostic performance for STAD patients.

Mechanism of PANoptosis in metabolic dysfunction-associated steatotic liver disease

In recent years, the incidence of metabolic dysfunction-associated steatotic liver disease (MASLD) has been steadily rising, emerging as a major chronic liver disease of global concern. The course of MASLD is varied, spanning from MASLD to metabolic dysfunction associated steatohepatitis (MASH). MASH is an important contributor to cirrhosis, which may subsequently lead to hepatocellular carcinoma. It has been found that PANoptosis, an emerging inflammatory programmed cell death (PCD), is involved in the pathogenesis of MASLD and facilitates the development of NASH, eventually resulting in inflammatory fibrosis and hepatocyte death. This paper reviews the latest research progress on PANoptosis and MASLD to understand the mechanism of MASLD and provide new directions for future treatment and drug development.

The Global Epidemic of Metabolic Fatty Liver Disease

PURPOSE OF REVIEW

The objective of this manuscript is to examine the current literature on the epidemiology of metabolic dysfunction-associated steatotic liver disease (MASLD), its correlation with cardiovascular disease (CVD) outcomes, as well as to evaluate the update in nomenclature from non-alcoholic liver disease (NAFLD).

RECENT FINDINGS

The update of diagnostic criteria from NAFLD to MASLD reduces the stigma associated with alcohol consumption and poor health choices. It also shines a light on the crucial role of cardiometabolic risk factors in disease pathophysiology. The incidence and prevalence of MASLD are projected to increase significantly in the future as the population burden of cardiometabolic risk factors rises. MASLD is also a potent risk factor for developing CVD that should be tackled by using a multi-disciplinary team with a holistic approach. As the new nomenclature for metabolic liver disease is adopted on a global scale, more research is needed to investigate the applicability of findings from previous trials focusing on NAFLD. It is anticipated that the epidemic of MASLD will continue to increase globally, hence the urgent need for therapeutic approaches to reverse this trend.

Uridine diphosphate glucuronosyltransferase 1A1 prevents the progression of liver injury

BACKGROUND

Uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) plays a crucial role in metabolizing and detoxifying endogenous and exogenous substances. However, its contribution to the progression of liver damage remains unclear.

AIM

To determine the role and mechanism of UGT1A1 in liver damage progression.

METHODS

We investigated the relationship between UGT1A1 expression and liver injury through clinical research. Additionally, the impact and mechanism of UGT1A1 on the progression of liver injury was analyzed through a mouse model study.

RESULTS

Patients with UGT1A1 gene mutations showed varying degrees of liver damage, while patients with acute-on-chronic liver failure (ACLF) exhibited relatively reduced levels of UGT1A1 protein in the liver as compared to patients with chronic hepatitis. This suggests that low UGT1A1 levels may be associated with the progression of liver damage. In mouse models of liver injury induced by carbon tetrachloride (CCl4) and concanavalin A (ConA), the hepatic levels of UGT1A1 protein were found to be increased. In mice with lipopolysaccharide or liver steatosis-mediated liver-injury progression, the hepatic protein levels of UGT1A1 were decreased, which is consistent with the observations in patients with ACLF. UGT1A1 knockout exacerbated CCl4- and ConA-induced liver injury, hepatocyte apoptosis and necroptosis in mice, intensified hepatocyte endoplasmic reticulum (ER) stress and oxidative stress, and disrupted lipid metabolism.

CONCLUSION

UGT1A1 is upregulated as a compensatory response during liver injury, and interference with this upregulation process may worsen liver injury. UGT1A1 reduces ER stress, oxidative stress, and lipid metabolism disorder, thereby mitigating hepatocyte apoptosis and necroptosis.

Unraveling Adipose Tissue Dysfunction: Molecular Mechanisms, Novel Biomarkers, and Therapeutic Targets for Liver Fat Deposition

Adipose tissue (AT), once considered a mere fat storage organ, is now recognized as a dynamic and complex entity crucial for regulating human physiology, including metabolic processes, energy balance, and immune responses. It comprises mainly two types: white adipose tissue (WAT) for energy storage and brown adipose tissue (BAT) for thermogenesis, with beige adipocytes demonstrating the plasticity of these cells. WAT, beyond lipid storage, is involved in various metabolic activities, notably lipogenesis and lipolysis, critical for maintaining energy homeostasis. It also functions as an endocrine organ, secreting adipokines that influence metabolic, inflammatory, and immune processes. However, dysfunction in WAT, especially related to obesity, leads to metabolic disturbances, including the inability to properly store excess lipids, resulting in ectopic fat deposition in organs like the liver, contributing to non-alcoholic fatty liver disease (NAFLD). This narrative review delves into the multifaceted roles of WAT, its composition, metabolic functions, and the pathophysiology of WAT dysfunction. It also explores diagnostic approaches for adipose-related disorders, emphasizing the importance of accurately assessing AT distribution and understanding the complex relationships between fat compartments and metabolic health. Furthermore, it discusses various therapeutic strategies, including innovative therapeutics like adipose-derived mesenchymal stem cells (ADMSCs)-based treatments and gene therapy, highlighting the potential of precision medicine in targeting obesity and its associated complications.

Endotoxin Inflammatory Action on Cells by Dysregulated-Immunological-Barrier-Linked ROS-Apoptosis Mechanisms in Gut-Liver Axis

Our study highlighted the immune changes by pro-inflammatory biomarkers in the gut-liver-axis-linked ROS-cell death mechanisms in chronic and acute inflammations when gut cells are exposed to endotoxins in patients with hepatic cirrhosis or steatosis. In duodenal tissue samples, gut immune barrier dysfunction was analyzed by pro-inflammatory biomarker expressions, oxidative stress, and cell death by flow cytometry methods. A significant innate and adaptative immune system reaction was observed as result of persistent endotoxin action in gut cells in chronic inflammation tissue samples recovered from hepatic cirrhosis with the A-B child stage. Instead, in patients with C child stage of HC, the endotoxin tolerance was installed in cells, characterized by T lymphocyte silent activation and increased Th1 cytokines expression. Interesting mechanisms of ROS-cell death were observed in chronic and acute inflammation samples when gut cells were exposed to endotoxins and immune changes in the gut-liver axis. Late apoptosis represents the chronic response to injury induction by the gut immune barrier dysfunction, oxidative stress, and liver-dysregulated barrier. Meanwhile, necrosis represents an acute and severe reply to endotoxin action on gut cells when the immune system reacts to pro-inflammatory Th1 and Th2 cytokines releasing, offering protection against PAMPs/DAMPs by monocytes and T lymphocyte activation. Flow cytometric analysis of pro-inflammatory biomarkers linked to oxidative stress-cell death mechanisms shown in our study recommends laboratory techniques in diagnostic fields.

Proanthocyanidins-Based Synbiotics as a Novel Strategy for Nonalcoholic Fatty Liver Disease (NAFLD) Risk Reduction

Nonalcoholic fatty liver disease (NAFLD), the most common liver disease worldwide, is a spectrum of liver abnormalities ranging from steatosis to nonalcoholic steatohepatitis (NASH) characterized by excessive lipid accumulation. The prevalence of NAFLD is predicted to increase rapidly, demanding novel approaches to reduce the global NAFLD burden. Flavonoids, the most abundant dietary polyphenols, can reduce the risk of NAFLD. The majority of dietary flavonoids are proanthocyanidins (PACs), which are oligomers and polymers of the flavonoid sub-group flavan-3-ols. The efficacy of PAC in reducing the NAFLD risk can be significantly hindered by low bioavailability. The development of synbiotics by combining PAC with probiotics may increase effectiveness against NAFLD by biotransforming PAC into bioavailable metabolites. PAC and probiotic bacteria are capable of mitigating steatosis primarily through suppressing de novo lipogenesis and promoting fatty acid β-oxidation. PAC and probiotic bacteria can reduce the progression of steatosis to NASH mainly through ameliorating hepatic damage and inflammation induced by hepatic oxidative stress, endoplasmic reticulum stress, and gut microbiota dysbiosis. Synbiotics of PAC are superior in reducing the risk of NAFLD compared to independent administration of PAC and probiotics. The development of PAC-based synbiotics can be a novel strategy to mitigate the increasing incidence of NAFLD.

Selenizing chitooligosaccharide with site-selective modification to alleviate acute liver injury in vivo

Two selenized chitooligosaccharide (O-Se-COS and N,O-Se-COS) with different sites modification were synthesized to alleviate liver injury in vivo. Comparing to traditional COS, both selenized COS exhibited enhanced reducibility as well as antioxidant capacity in vitro. Furthermore, O-Se-COS demonstrated superior efficacy in reducing intracellular reactive oxygen species (ROS) and mitochondrial damage compared to N,O-Se-COS as its enhanced cellular uptake by the positive/negative charge interactions. Two mechanisms were proposed to explained these results: one is to enhance the enzymatic activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), which effectively scavenge free radicals; the other is to down-regulate intracellular cytochrome P450 (CYP2E1) levels, inhibiting carbon tetrachloride (CCl4)-induced peroxidation damage. In vivo studies further demonstrated the effective alleviation of CCl4-induced liver injury by selenized COS, with therapeutic efficacy observed in the following order: O-Se-COS > N,O-Se-COS > COS. Finally, hemolysis and histological tests confirmed the biosafety of both selenized COS. Taken together, these finding demonstrated that selenium has the potential to improve the biological activity of COS, and precise selenylation was more conducive to achieving the synergistic effect where 1 + 1>2.

Cellular and molecular effects of fipronil in lipid metabolism of HepG2 and its possible connection to non-alcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a global public health problem that affects more than a quarter of the population. The development of this disease is correlated with metabolic dysfunctions that lead to lipid accumulation in the liver. Pesticides are one of etiologies that support NAFLD establishment. Therefore, the effects of the insecticide fipronil on the lipid metabolism of the human hepatic cell line, HepG2, was investigated, considering its widespread use in field crops and even to control domestic pests. To address the goals of the study, biochemical, cellular, and molecular analyses of different concentrations of fipronil in cell cultures were investigated, after 24 h of incubation. Relevant metabolites such as triglycerides, glucose levels, β-oxidation processes, and gene expression of relevant elements correlated with lipid and metabolism of xenobiotics were investigated. The results suggested that at 20 μM, the pesticide increased the accumulation of triglycerides and neutral lipids by reducing fatty acid oxidation and increasing de novo lipogenesis. In addition, changes were observed in genes that control oxidative stress and the xenobiotic metabolism. Together, the results suggest that the metabolic changes caused by the insecticide fipronil may be deleterious if persistent, favoring the establishment of hepatic steatosis.

Associations between types and sources of dietary carbohydrates and liver fat: a UK Biobank study

BACKGROUND AND AIMS

Excess energy intake can lead to metabolic dysfunction-associated steatotic liver disease (MASLD), but the relationship between dietary carbohydrate intake and liver fat content remains unclear. This study aimed to examine the associations between types and sources of dietary carbohydrates and liver fat content.

METHODS

UK Biobank participants with no pre-existing diabetes, liver disease or cardiovascular disease reported dietary intake of types and sources of carbohydrates (total carbohydrates, free sugars, non-free sugars, starch from whole grains, starch from refined grains, and fibre) on at least two 24-h dietary assessments. In cross-sectional analyses, (n = 22,973), odds ratios (OR) of high liver fat content (defined as a score of ≥ 36 in the hepatic steatosis index) by quintiles of carbohydrate intakes were estimated using multivariable logistic regression models. In prospective analyses, a second sample (n = 9268) had liver proton density fat fraction (PDFF) measured by magnetic resonance imaging (2014-2020). Multivariable linear regression models estimated geometric means of PDFF (%) by quintiles of carbohydrate intakes. Models were adjusted for demographic and lifestyle confounders, including total energy intake.

RESULTS

In the cross-sectional analyses, 6894 cases of high liver fat content were identified. Inverse associations between intakes of fibre (OR of highest vs. lowest quintile 0.46 [95% CI: 0.41-0.52]), non-free sugars (0.63 [0.57-0.70]) and starch from whole grains (0.52 [0.47-0.57]) with liver fat were observed. There were positive associations between starch from refined grains and liver fat (1.33 [1.21-1.46]), but no association with free sugars (p=0.61). In prospective analyses, inverse associations with PDFF (%) were observed for intakes of fibre (- 0.48 geometric mean difference between highest and lowest quintile of intake [- 0.60 to - 0.35]), non-free sugars (- 0.37 [- 0.49 to - 0.25]) and starch from whole grains (- 0.31 [- 0.42 to - 0.19]). Free sugars, but not starch from refined grains, were positively associated with PDFF (0.17 [0.05 to 0.28]).

CONCLUSION

This study suggests that different carbohydrate types and sources have varying associations with liver fat, which may be important for MASLD prevention. Non-free sugars, fibre, and starch from whole grains could be protective, while associations with free sugars and starch from refined grains are less clear.

Circ_0004535/miR-1827/CASP8 network involved in type 2 diabetes mellitus with nonalcoholic fatty liver disease

Diagnostic delay in type 2 diabetes mellitus (T2DM) with nonalcoholic fatty liver disease (NAFLD) patients often leads to a serious public health problem. Understanding the pathophysiological mechanisms of disease will help develop more effective treatments. High-throughput sequencing was used to determine the expression levels of circRNAs, and mRNAs in health controls, T2DM patients, and T2DM with NAFLD patients. Differentially expressed genes (DEcircRs, DEmRs) in T2DM with NAFLD were identified by differential analysis. The miRNAs with targeted relationship with the DEcircRs and DEmRs were respectively predicted to construct a ceRNA regulatory network. In addition, enrichment analysis of DEmRs in the ceRNA network was performed. The expression of important DEcircRs was further validated by quantitative real-time PCR (qRT-PCR). The steatosis was detected in glucose treated LO2 cells by overexpressing circ_0004535, and CASP8. There were 586 DEmRs, and 10 DEcircRs in both T2DM and T2DM with NAFLD patients. Combined with predicted results and differential analysis, the ceRNA networks were constructed. The DEmRs in the ceRNA networks were mainly enriched in Toll-like receptor signaling pathway, and apoptosis. Importantly, dual luciferase experiments validated the targeted binding of hsa_circ_0004535 and hsa-miR-1827 or hsa-miR-1827 and CASP8. qRT-PCR experiments validated that hsa_circ_0004535, and CASP8 was downregulated and hsa-miR-1827 was upregulated expression in peripheral blood of T2DM with NAFLD patients. Abnormal cell morphology, and increased lipid droplet fusion were observed in the glucose treated LO2 cells, overexpression of circ_0004535 and CASP8 ameliorated these changes. Our work provides a deeper understanding of ceRNA mediated pathogenesis of T2DM with NAFLD and provides a novel strategy for treatment.

The Involvement of Calcium Channels in the Endoplasmic Reticulum Membrane in Nonalcoholic Fatty Liver Disease Pathogenesis

Nonalcoholic fatty liver disease (NAFLD) is a prevalent and complex condition that affects millions of people globally. It occurs when fat, primarily triglycerides, accumulates in liver cells, leading to inflammation and damage. Calcium, an essential mineral, is involved in various physiological processes, including the regeneration process following liver injury. The endoplasmic reticulum (ER), a complex organelle involved in protein synthesis and lipid metabolism, regulates intracellular calcium levels. Dysregulation of this process can lead to calcium overload, oxidative stress, and cellular damage, all of which are hallmarks of NAFLD. Inositol 1,4,5-trisphosphate receptor (IP3R), a type of calcium ion channel, is found throughout the body, including the liver. IP3R is classified into three subtypes: IP3R1, IP3R2, and IP3R3, and it plays a critical role in regulating intracellular calcium levels. However, excessive calcium accumulation in the mitochondria due to an overload of calcium ions or increased IP3R activity can lead to NAFLD. Therefore, targeting calcium channels in the ER membrane may represent a promising therapeutic strategy for preventing and treating this increasingly prevalent metabolic disorder. It may help prevent mitochondrial calcium accumulation and reduce the risk of hepatic damage. This review article aimed to review the relationship between IP3R modulation and the pathogenicity of NAFLD, providing valuable insights to help researchers develop more effective treatments for the condition.

The Crosstalk between Mesenchymal Stromal/Stem Cells and Hepatocytes in Homeostasis and under Stress

Liver diseases, characterized by high morbidity and mortality, represent a substantial medical problem globally. The current therapeutic approaches are mainly aimed at reducing symptoms and slowing down the progression of the diseases. Organ transplantation remains the only effective treatment method in cases of severe liver pathology. In this regard, the development of new effective approaches aimed at stimulating liver regeneration, both by activation of the organ's own resources or by different therapeutic agents that trigger regeneration, does not cease to be relevant. To date, many systematic reviews and meta-analyses have been published confirming the effectiveness of mesenchymal stromal cell (MSC) transplantation in the treatment of liver diseases of various severities and etiologies. However, despite the successful use of MSCs in clinical practice and the promising therapeutic results in animal models of liver diseases, the mechanisms of their protective and regenerative action remain poorly understood. Specifically, data about the molecular agents produced by these cells and mediating their therapeutic action are fragmentary and often contradictory. Since MSCs or MSC-like cells are found in all tissues and organs, it is likely that many key intercellular interactions within the tissue niches are dependent on MSCs. In this context, it is essential to understand the mechanisms underlying communication between MSCs and differentiated parenchymal cells of each particular tissue. This is important both from the perspective of basic science and for the development of therapeutic approaches involving the modulation of the activity of resident MSCs. With regard to the liver, the research is concentrated on the intercommunication between MSCs and hepatocytes under normal conditions and during the development of the pathological process. The goals of this review were to identify the key factors mediating the crosstalk between MSCs and hepatocytes and determine the possible mechanisms of interaction of the two cell types under normal and stressful conditions. The analysis of the hepatocyte-MSC interaction showed that MSCs carry out chaperone-like functions, including the synthesis of the supportive extracellular matrix proteins; prevention of apoptosis, pyroptosis, and ferroptosis; support of regeneration; elimination of lipotoxicity and ER stress; promotion of antioxidant effects; and donation of mitochondria. The underlying mechanisms suggest very close interdependence, including even direct cytoplasm and organelle exchange.

Effects of 3021 meal replacement powder protect NAFLD via suppressing the ERS, oxidative stress and inflammatory responses

Objective

To explore the specific protective mechanism of 3021 meal replacement powder (MRP) against non-alcoholic fatty liver disease (NAFLD).

Materials and Methods

C57BL/6J male mice were divided into four groups: control group, 3021 MRP group, model group and test group. The lipid accumulation and endoplasmic reticulum stress (ERS)-related proteins in hepatocytes of mice were detected by hematoxylin-eosin (HE) staining, oil red O staining and Western blotting.

Results

The expressions of GRP78, GRP94, p-PERK and p-IRE1α were significantly inhibited in test group compared with those in model group. The protein expressions of p-NF-κB, p-JNK, IL-1β, IL-18 and NOX4 in test group were also significantly lower than those in model group. In vivo and in vitro experiments revealed that the body weight and lipid droplet content, and the expressions of ERS-related proteins (including BIP and XBP-1) in liver tissues all significantly declined in model group compared with those in 3021 MRP group.

Conclusion

In conclusion, 3021 MRP can greatly reduce lipid accumulation by inhibiting ERS, oxidative stress and inflammatory response in NAFLD.

High Gamma-Aminobutyric Acid (GABA) Oolong Tea Alleviates High-Fat Diet-Induced Metabolic Disorders in Mice

Obesity and overweight are associated with an increasing risk of developing health conditions and chronic non-communicable diseases, including cardiovascular diseases, cancer, musculoskeletal problems, respiratory problems, and mental health, and its prevalence is rising. Diet is one of three primary lifestyle interventions. Many bioactive components in tea especially oolong tea, including flavonoids, gamma-aminobutyric acid (GABA), and caffeine were reported to show related effects in reducing the risk of obesity. However, the effects of GABA oolong tea extracts (OTEs) on high-fat diet (HFD)-induced obesity are still unclear. Therefore, this study aims to explore whether the intervention of GABA OTEs can prevent HFD-induced obesity and decipher its underlying mechanisms using male C57BL/6 J mice. The result indicated that GABA OTEs reduced leptin expression in epididymal adipose tissue and showed a protective effect on nonalcoholic fatty liver disease. It promoted thermogenesis-related protein of uncoupling protein-1 and peroxisome proliferator-activated receptor-gamma coactivator (PGC-1α), boosted lipid metabolism, and promoted fatty acid oxidation. It also reduced lipogenesis-related protein levels of sterol regulatory element binding protein, acetyl-CoA carboxylase, and fatty acid synthase and inhibited hepatic triglyceride (TG) levels. These data suggest that regular drinking of GABA oolong tea has the potential to reduce the risk of being overweight, preventing obesity development through thermogenesis, lipogenesis, and lipolysis.

The emerging significance of mitochondrial targeted strategies in NAFLD treatment

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease worldwide, ranging from liver steatosis to nonalcoholic steatohepatitis, which ultimately progresses to fibrosis, cirrhosis, and hepatocellular carcinoma. Individuals with NAFLD have a higher risk of developing cardiovascular and extrahepatic cancers. Despite the great progress being made in understanding the pathogenesis and the introduction of new pharmacological targets for NAFLD, no drug or intervention has been accepted for its management. Recent evidence suggests that NAFLD may be a mitochondrial disease, as mitochondrial dysfunction is involved in the pathological processes that lead to NAFLD. In this review, we describe the recent advances in our understanding of the mechanisms associated with mitochondrial dysfunction in NAFLD progression. Moreover, we discuss recent advances in the efficacy of mitochondria-targeted compounds (e.g., Mito-Q, MitoVit-E, MitoTEMPO, SS-31, mitochondrial uncouplers, and mitochondrial pyruvate carrier inhibitors) for treating NAFLD. Furthermore, we present some medications currently being tested in clinical trials for NAFLD treatment, such as exercise, mesenchymal stem cells, bile acids and their analogs, and antidiabetic drugs, with a focus on their efficacy in improving mitochondrial function. Based on this evidence, further investigations into the development of mitochondria-based agents may provide new and promising alternatives for NAFLD management.

Coagulation Dysfunctions in Non-Alcoholic Fatty Liver Disease-Oxidative Stress and Inflammation Relevance

Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases. Its incidence is progressively rising and it is possibly becoming a worldwide epidemic. NAFLD encompasses a spectrum of diseases accounting for the chronic accumulation of fat within the hepatocytes due to various causes, excluding excessive alcohol consumption. In this study, we aimed to focus on finding evidence regarding the implications of oxidative stress and inflammatory processes that form the multifaceted pathophysiological tableau in relation to thrombotic events that co-occur in NAFLD and associated chronic liver diseases. Recent evidence on the pathophysiology of NAFLD suggests that a complex pattern of multidirectional components, such as prooxidative, proinflammatory, and prothrombotic components, better explains the multiple factors that promote the mechanisms underlying the fatty acid excess and subsequent processes. As there is extensive evidence on the multi-component nature of NAFLD pathophysiology, further studies could address the complex interactions that underlie the development and progression of the disease. Therefore, this study aimed to describe possible pathophysiological mechanisms connecting the molecular impairments with the various clinical manifestations, focusing especially on the interactions among oxidative stress, inflammation, and coagulation dysfunctions. Thus, we described the possible bidirectional modulation among coagulation homeostasis, oxidative stress, and inflammation that occurs in the various stages of NAFLD.

Thioredoxin/Glutaredoxin Systems and Gut Microbiota in NAFLD: Interplay, Mechanism, and Therapeutical Potential

Non-alcoholic fatty liver disease (NAFLD) is a common clinical disease, and its pathogenesis is closely linked to oxidative stress and gut microbiota dysbiosis. Recently accumulating evidence indicates that the thioredoxin and glutaredoxin systems, the two thiol-redox dependent antioxidant systems, are the key players in the NAFLD's development and progression. However, the effects of gut microbiota dysbiosis on the liver thiol-redox systems are not well clarified. This review explores the role and mechanisms of oxidative stress induced by bacteria in NAFLD while emphasizing the crucial interplay between gut microbiota dysbiosis and Trx mediated-redox regulation. The paper explores how dysbiosis affects the production of specific gut microbiota metabolites, such as trimethylamine N-oxide (TMAO), lipopolysaccharides (LPS), short-chain fatty acids (SCFAs), amino acids, bile acid, and alcohol. These metabolites, in turn, significantly impact liver inflammation, lipid metabolism, insulin resistance, and cellular damage through thiol-dependent redox signaling. It suggests that comprehensive approaches targeting both gut microbiota dysbiosis and the thiol-redox antioxidant system are essential for effectively preventing and treating NAFLD. Overall, comprehending the intricate relationship between gut microbiota dysbiosis and thiol-redox systems in NAFLD holds significant promise in enhancing patient outcomes and fostering the development of innovative therapeutic interventions.

A new perspective on mesenchymal stem cell-based therapy for liver diseases: restoring mitochondrial function

Mesenchymal stem cells (MSCs) have emerged as a promising alternative treatment for liver disease due to their roles in regeneration, fibrosis inhibition, and immunoregulation. Mitochondria are crucial in maintaining hepatocyte integrity and function. Mitochondrial dysfunction, such as impaired synthesis of adenosine triphosphate (ATP), decreased activity of respiratory chain complexes, and altered mitochondrial dynamics, is observed in most liver diseases. Accumulating evidence has substantiated that the therapeutic potential of MSCs is mediated not only through their cell replacement and paracrine effects but also through their regulation of mitochondrial dysfunction in liver disease. Here, we comprehensively review the involvement of mitochondrial dysfunction in the development of liver disease and how MSCs can target mitochondrial dysfunction. We also discuss recent advances in a novel method that modifies MSCs to enhance their functions in liver disease. A full understanding of MSC restoration of mitochondrial function and the underlying mechanisms will provide innovative strategies for clinical applications. Video Abstract.

New discoveries in the field of metabolism by applying single-cell and spatial omics

Single-cell multi-Omics (SCM-Omics) and spatial multi-Omics (SM-Omics) technologies provide state-of-the-art methods for exploring the composition and function of cell types in tissues/organs. Since its emergence in 2009, single-cell RNA sequencing (scRNA-seq) has yielded many groundbreaking new discoveries. The combination of this method with the emergence and development of SM-Omics techniques has been a pioneering strategy in neuroscience, developmental biology, and cancer research, especially for assessing tumor heterogeneity and T-cell infiltration. In recent years, the application of these methods in the study of metabolic diseases has also increased. The emerging SCM-Omics and SM-Omics approaches allow the molecular and spatial analysis of cells to explore regulatory states and determine cell fate, and thus provide promising tools for unraveling heterogeneous metabolic processes and making them amenable to intervention. Here, we review the evolution of SCM-Omics and SM-Omics technologies, and describe the progress in the application of SCM-Omics and SM-Omics in metabolism-related diseases, including obesity, diabetes, nonalcoholic fatty liver disease (NAFLD) and cardiovascular disease (CVD). We also conclude that the application of SCM-Omics and SM-Omics approaches can help resolve the molecular mechanisms underlying the pathogenesis of metabolic diseases in the body and facilitate therapeutic measures for metabolism-related diseases. This review concludes with an overview of the current status of this emerging field and the outlook for its future.

Investigation of FGF21 mRNA levels and relative mitochondrial DNA copy number levels and their relation in nonalcoholic fatty liver disease: a case-control study

Background: Although the exact mechanisms of nonalcoholic fatty liver disease (NAFLD) are not fully understood, numerous pieces of evidence show that the variations in mitochondrial DNA (mtDNA) level and hepatic Fibroblast growth factor 21 (FGF21) expression may be related to NAFLD susceptibility. Objectives: The main objective of this study was to determine relative levels of mtDNA copy number and hepatic FGF21 expression in a cohort of Iranian NAFLD patients and evaluate the possible relationship. Methods: This study included 27 NAFLD patients (10 with nonalcoholic fatty liver (NAFL) and 17 with non-alcoholic steatohepatitis (NASH)) and ten healthy subjects. Total RNA and genomic DNA were extracted from liver tissue samples, and then mtDNA copy number and FGF21 expression levels were assessed by quantitative real-time PCR. Results: The relative level of hepatic mtDNA copy number was 3.9-fold higher in patients than in controls (p < 0.0001). NAFLD patients showed a 2.9-fold increase in hepatic FGF21 expression compared to controls (p < 0.013). Results showed that hepatic FGF21 expression was positively correlated with BMI, serum ALT, and AST levels (p < 0.05). The level of mitochondrial copy number and hepatic FGF21 expression was not significantly associated with stages of change in hepatic steatosis. Finally, there was a significant correlation between FGF21 expression and mitochondrial copy number in NAFLD patients (p = 0.027). Conclusion: Our findings suggest a considerable rise of hepatic FGF21 mRNA levels and mtDNA-CN and show a positive correlation between them in the liver tissue of NAFLD patients.

5-HT3 Receptors on Mitochondria Influence Mitochondrial Function

The 5-hydroxytryptamine 3 (5-HT₃) receptor belongs to the pentameric ligand-gated cation channel superfamily. Humans have five different 5-HT₃ receptor subunits: A to E. The 5-HT₃ receptors are located on the cell membrane, but a previous study suggested that mitochondria could also contain A subunits. In this article, we explored the distribution of 5-HT₃ receptor subunits in intracellular and cell-free mitochondria. Organelle prediction software supported the localization of the A and E subunits on the inner membrane of the mitochondria. We transiently transfected HEK293T cells that do not natively express the 5-HT₃ receptor with an epitope and fluorescent protein-tagged 5HT3A and 5HT3E subunits. Fluorescence microscopy and cell fractionation indicated that both subunits, A and E, localized to the mitochondria, while transmission electron microscopy revealed the location of the subunits on the mitochondrial inner membrane, where they could form heteromeric complexes. Cell-free mitochondria isolated from cell culture media colocalized with the fluorescent signal for A subunits. The presence of A and E subunits influenced changes in the membrane potential and mitochondrial oxygen consumption rates upon exposure to serotonin; this was inhibited by pre-treatment with ondansetron. Therefore, it is likely that the 5-HT₃ receptors present on mitochondria directly impact mitochondrial function and that this may have therapeutic implications.

Hepatic Alarmins and Mitochondrial Dysfunction under Residual Hyperlipidemic Stress Lead to Irreversible NAFLD

BACKGROUND AND AIMS

Nonalcoholic fatty liver disease (NAFLD) includes a range of progressive disorders generated by excess lipid accumulation in the liver leading to hepatic steatosis and eventually fibrosis. We aimed to identify by high performance mass spectrometry-based proteomics the main signaling pathways and liver proteome changes induced by hypercholesterolemia in a rabbit atherosclerotic model that induced high accumulation of lipids in the liver.

METHODS

The effect of combined lipid-lowering drugs (statins and anti-PCSK9 monoclonal antibody) were used after the interruption of the hypercholesterolemic diet to identify also the potential mediators, such as alarmins, responsible for the irreversible NAFLD build up under the hyperlipidemic sustained stress.

RESULTS

Proteomic analysis revealed a number of proteins whose abundance was altered. They were components of metabolic pathways including fatty-acid degradation, glycolysis/gluconeogenesis, and nonalcoholic fatty liver disease. Mitochondrial dysfunction indicated alteration at the mitochondrial respiratory chain level and down-regulation of NADH: ubiquinone oxidoreductase. The expression of a majority of cytochromes (P4502E1, b5, and c) were up-regulated by lipid-lowering treatment. Long-term hyperlipidemic stress, even with a low-fat diet and lipid-lowering treatment, was accompanied by alarmin release (annexins, galectins, HSPs, HMGB1, S100 proteins, calreticulin, and fibronectin) that generated local inflammation and induced liver steatosis and aggressive fibrosis (by high abundance of galectin 3, fibronectin, and calreticulin).

CONCLUSIONS

The novel findings of this study were related to the residual effects of hyperlipidemic stress with consistent, combined lipid-lowering treatment with statin and inhibitor of PCSK9.

Vanillic acid mitigates hyperinsulinemia induced ER stress mediated altered calcium homeostasis, MAMs distortion and surplus lipogenesis in HepG2 cells

Hyperinsulinemia (HI) induced insulin resistance (IR) and associated pathologies are the burning and unsolvable issues in diabetes treatment. The cellular, molecular and biochemical events associated with HI are not yet elucidated. Similarly, no focused research on designing therapeutic strategies with natural products for attenuation of HI are seen in literature. Keeping this in mind we planned the present study to evaluate the alterations occurring at ER/Ca²⁺ homeostasis/mitochondria associated endoplasmic reticulum membranes (MAMs) in HepG2 cells during HI and to evaluate the possible beneficial effect of vanillic acid (VA) to mitigate the complications. An in vitro model of HI was established by treating HepG2 cells with human insulin (1 μM) for 24 h. Then, ER stress, Ca²⁺ homeostasis, MAMs, IR and hepatic lipogenesis were studied at protein level. Various proteins critical to ER, Ca²⁺ homeostasis and MAMs such as p-IRE-1α, ATF6, p-PERK, p-eIF2α, CHOP, XBP1, p-CAMKII, InsP3R, SERCA, JNK, GRP78, VDAC, Cyp D, GRP75, MFN2, PTEN and mTORC were studied and found altered significantly causing ER stress, defect in Ca²⁺ movements and distortion of MAMs. The decreased expression of IRS2 and an unaltered expression of IRS1 confirmed the development of selective insulin resistance in hepatocytes during HI and this was the crucial factor for the progression of the hepatic lipid accumulation. We found simultaneous treatment of VA is beneficial up to a certain extent to protect HepG2 cells from the adverse effect of HI via its antioxidant, antilipogenic, mitochondrial and ER protection properties.

Atherogenic Index of Plasma (AIP) and Its Association with Fatty Liver in Obese Adolescents

Background: The atherogenic index of plasma (AIP) is the base-10 logarithmic conversion of the triglyceride to high-density lipoprotein cholesterol ratio [AIP = log10 (triglyceride/HDL cholesterol)]. Some studies have found a link between low serum vitamin D levels, AIP, and fatty liver. This study was conducted to evaluate the relationship between AIP levels, fatty liver, and vitamin D levels in obese adolescents aged 10–17 years. Methods: This study included 136 adolescents, including 83 obese and 53 healthy controls, in the age range of 10–17 years. Thirty-nine of the obese adolescents had fatty livers. Those with ultrasonography grades 2 or 3 of fat were in the fatty liver group. The AIP value was calculated as the logarithmic conversion of the ratio (triglyceride/HDL cholesterol) at the base of 10. Vitamin D and other laboratory tests were analyzed biochemically. Statistical evaluations were made with the SPSS program. Results: The AIP, body mass index (BMI), homeostatic model assessment for insulin resistance (HOMA-IR), and insulin averages of obese adolescents with fatty liver were significantly higher than those of obese adolescents without fatty liver and the healthy control group (p < 0.05). Again, the mean AIP of obese patients without fatty liver was pointedly higher than that of the healthy control group (p < 0.05). There was a positive, moderate relationship between AIP and BMI, AIP and HOMA-IR, and AIP and insulin levels (p < 0.05), whereas there was a negative, moderate (37.3%) relationship between AIP and vitamin D (p = 0.019). Conclusion: AIP levels were higher in obese adolescents, and this increase was higher in obese adolescents with fatty liver in this study. Moreover, we detected a negative correlation between AIP and vitamin D levels and a positive correlation with BMI, insulin resistance, and insulin levels. Based on our data, we concluded that AIP can be a useful predictor of fatty liver in obese adolescents.

Distinct Role of Lycium barbarum L. Polysaccharides in Oxidative Stress-Related Ocular Diseases

Oxidative stress is an imbalance between the increased production of reactive species and reduced antioxidant activity, which can cause a variety of disturbances including ocular diseases. Lycium barbarum polysaccharides (LBPs) are complex polysaccharides isolated from the fruit of L. barbarum, showing distinct roles in antioxidants. Moreover, it is relatively safe and non-toxic. In recent years, the antioxidant activities of LBPs have attracted remarkable attention. In order to illustrate its significance and underlying therapeutic value for vision, we comprehensively review the recent progress on the antioxidant mechanisms of LBP and its potential applications in ocular diseases, including diabetic retinopathy, hypertensive neuroretinopathy, age-related macular degeneration, retinitis pigmentosa, retinal ischemia/reperfusion injury, glaucoma, dry eye syndrome, and diabetic cataract.

Screening of Biomarkers in Liver Tissue after Bariatric Surgery Based on WGCNA and SVM-RFE Algorithms

As the most common chronic liver disease around the world, nonalcoholic fatty liver disease (NAFLD) has a close connection with obesity, diabetes, and metabolic syndrome. Bariatric surgery (BS) is considered to be the most effective treatment for NAFLD. However, the regulatory mechanism of hepatic lipid metabolism after BS remains poorly elucidated. By analyzing two transcriptome datasets regarding liver tissues after BS, namely, GSE83452 and GSE106737, we acquired 110 differentially expressed genes (DEGs). By further analysis of DEGs in terms of the weighted gene coexpression network analysis (WGCNA) and support vector machine-recursive feature elimination (SVM-RFE) algorithms, we identified four crucial genes participating in the regulation of hepatic lipid metabolism: SRGN, THEMIS2, SGK1, and FPR3. In addition, the results of gene set enrichment analysis (GSEA) showed that BS can activate immune-related regulatory pathways and change immune cell infiltration levels. Finally, through cellular level studies, we found that the silencing of SRGN affects the expression of SREBP-1, SIRT1, and FAS during adipogenesis in the liver and the formation of lipid droplets in the liver. In summary, the immune system in the liver is activated after BS, and SRGN participates in the regulation of hepatic lipid metabolism.

Peonidin-3-O-Glucoside from Purple Corncob Ameliorates Nonalcoholic Fatty Liver Disease by Regulating Mitochondrial and Lysosome Functions to Reduce Oxidative Stress and Inflammation

A frequent chronic liver condition across the world is nonalcoholic fatty liver disease (NAFLD). Oxidative stress caused by lipid accumulation is generally considered to be the main cause of NAFLD. Anthocyanins can effectively inhibit the production of reactive oxygen species and improve oxidative stress. In this work, six major anthocyanins were separated from purple corncob by semi-preparative liquid chromatography. The effects of the 6 kinds of anthocyanins against NAFLD were investigated using a free fatty acid (FFA)-induced cell model. The results showed that peonidin 3-O-glucoside (P3G) can significantly reduce lipid accumulation in the NAFLD cell model. The treatment with P3G also inhibited oxidative stress via inhibiting the excessive production of reactive oxygen species and superoxide anion, increasing glutathione levels, and enhancing the activities of SOD, GPX, and CAT. Further studies unveiled that treatment with P3G not only alleviated inflammation but also improved the depletion of mitochondrial content and damage of the mitochondrial electron transfer chain developed concomitantly in the cell model. P3G upregulated transcription factor EB (TFEB)-mediated lysosomal function and activated the peroxisome proliferator-activated receptor alpha (PPARα)-mediated peroxisomal lipid oxidation by interacting with PPARα possibly. Overall, this study added to our understanding of the protective effects of purple corn anthocyanins against NAFLD and offered suggestions for developing functional foods containing these anthocyanins.

Genetic polymorphisms of Ca2+ transport proteins and molecular chaperones in mitochondria-associated endoplasmic reticulum membrane and non-alcoholic fatty liver disease

Background

Non-alcoholic fatty liver disease (NAFLD) is recognized to be closely associated with endoplasmic reticulum stress and mitochondrial dysfunction, while previous studies have emphasized the important role of calcium homeostasis from the mitochondria-associated endoplasmic reticulum membrane (MAM) in the endoplasmic reticulum and mitochondria. This article will assess the association between genetic polymorphisms of Ca2+ transport proteins and molecular chaperones in MAM and NAFLD risk.

Methods

A case-control study was conducted in a community of Nanjing, China during April to December 2020. 2701 subjects were enrolled and genotyped for 6 genetic variants in HSPA5 and ITPR2 genes. Logistic regression analysis was used to assess impact of these variants on NAFLD risk.

Results

After adjusting for age, gender, total cholesterol and glucose, we identified that HSPA5 rs12009 variant genotypes (recessive model: OR= 0.801, 95% CI= 0.652-0.986, P= 0.036), rs430397 variant genotypes (recessive model: OR= 0.546, 95% CI= 0.314-0.950, P= 0.032), and ITPR2 rs11048570 variant genotypes (recessive model: OR= 0.673, 95% CI= 0.453-0.999, P= 0.049) were associated with a reduced risk of NAFLD. Multivariate stepwise regression analysis indicated that gender, glucose, body mass index, triglycerides and favorable alleles were independent influencers of NAFLD (all P< 0.05). The area under the receiver operating characteristic curve was 0.764 (95% CI= 0.745-0.783, P< 0.001).

Conclusion

The variant genotypes of Ca2+ transport-associated genes HSPA5 (rs12009 and rs430397) and ITPR2 (rs11048570) might contribute to the reduction of the NAFLD risk in Chinese Han population, which can provide new insight into NAFLD pathogenesis.

Liver immune and lipid metabolism disorders in mice induced by triphenyl phosphate with or without high fructose and high fat diet

Organophosphorus flame retardants (OPFRs) are frequently detected in food and human samples, and epidemiological studies have found that human exposure to aryl-OPFRs (triphenyl phosphate, TPP) is associated with lipid metabolism. Although toxicity studies suggest a potential obesity risk from TPP exposure, the molecular mechanism remains unclear. This study investigated the subchronic dietary effects on mouse liver significantly changed proteins (SCPs) and elucidated the underlying molecular mechanisms of TPP with or without a high-fructose and high-fat (HFF) diet. Male C57BL/6J mice were exposed to low-dose TPP (corresponding to the oral reference dose, 10 μg/kg body weight (bw)/day) and high-dose TPP (1000 μg/kg bw/day) for 12 weeks. The results showed that exposure to TPP generated changes of liver function and organelle damage as well as increases in total cholesterol and triglyceride levels. TPP exposure at a low dose damaged the liver immune system via major histocompatibility complex-related proteins involved in antigen processing and presentation. TPP exposure at a high dose caused disorders of the biosynthesis of unsaturated fatty acids and steroid hormones, thereby inducing lipid accumulation in the liver. Although 10 μg/kg TPP did not cause serious lipid metabolism disorders in the liver, significant overexpression of fatty acid-binding protein 5, malic enzyme 1, and other related SCPs was observed, which led to disorders of cholesterol metabolism and lipogenesis to activate the proliferator-activated receptor signaling pathway and thus induced potential obesity risks. In addition, lipid metabolism disorders related to TPP were aggravated under the HFF diet, impairing liver mitochondrial and endoplasmic reticulum function in mice by altering the activity of cytochrome P450 enzyme subfamilies. These findings provide an in-depth understanding of the molecular toxicity mechanisms and health risks associated with subchronic exposure to TPP under different dietary regimes.

Involvement of oxidative species in cyclosporine-mediated cholestasis

Cyclosporine is an established medication for the prevention of transplant rejection. However, adverse consequences such as nephrotoxicity, hepatotoxicity, and cholestasis have been associated with prolonged usage. In cyclosporine-induced obstructive and chronic cholestasis, for example, the overproduction of oxidative stress is significantly increased. Additionally, cyclosporine exerts adverse effects on liver function and redox balance responses in treated rats, as evidenced by its increasing levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and bilirubin while also decreasing the levels of glutathione and NADPH. Cyclosporine binds to cyclophilin to produce its therapeutic effects, and the resulting complex inhibits calcineurin, causing calcium to accumulate in the mitochondria. Accumulating calcium with concomitant mitochondrial abnormalities induces oxidative stress, perturbation in ATP balance, and failure of calcium pumps. Also, cyclosporine-induced phagocyte oxidative stress generation via the interaction of phagocytes with Toll-like receptor-4 has been studied. The adverse effect of cyclosporine may be amplified by the release of mitochondrial DNA, mediated by oxidative stress-induced mitochondrial damage. Given the uncertainty surrounding the mechanism of cyclosporine-induced oxidative stress in cholestasis, we aim to illuminate the involvement of oxidative stress in cyclosporine-mediated cholestasis and also explore possible strategic interventions that may be applied in the future.

Bone Metabolism Discrepancy in Type 2 Diabetes Mellitus Patients With and Without Non-Alcoholic Fatty Liver Disease

To explore the distribution of several bone metabolic indicators in type 2 diabetes patients (T2DM) with and without non-alcoholic fatty liver disease (NAFLD) and to preliminarily evaluate the relationship of bone metabolism with NAFLD in patients with T2DM. The hospitalized patients with T2DM were divided into the group of T2DM complicated with NAFLD and the group of T2DM alone according to the results of ultrasonic diagnosis. The general information and laboratory test data such as bone metabolism indexes of these patients were collected and the differences of the indexes between the 2 groups were compared. Furthermore, the independent influencing factors of NAFLD in patients with T2DM were analyzed. A total of 186 patients were included in the study. Compared with patients with T2DM only, patients with T2DM combined with NAFLD were characterized with younger age (p &lt; 0.001), higher BMI (p = 0.016), ALT (p = 0.001), TG (p = 0.005), HOMA-IR (p = 0.005), and lower HDL-C (p = 0.031). Significant discrepancy of age (OR 1.052, p = 0.001), ALT (OR 0.964, p = 0.047), HOMA-IR (OR 0.801, p = 0.005), and T-PINP (OR 1.022, p = 0.008) was found using multivariate logistic regression model. Significant discrepancy of T-PINP was found in T2DM patients with and without NAFLD. Further studies are needed to explore whether T-PINP could be used as a predictor of fatty liver disease, osteoporosis, and other related complications in patients with T2DM.

Mitofusin-2 in cancer: Friend or foe?

Cancer is a category of disorders characterized by excessive cell proliferation with the ability to infiltrate or disseminate to other organs of the body. Mitochondrial dysfunction, as one of the most prominent hallmarks of cancer cells, has been related to the onset and development of various cancers. Mitofusin 2 (MFN2) is a major mediator of mitochondrial fusion, endoplasmic reticulum (ER)-mitochondria interaction, mitophagy and axonal transport of mitochondria. Available data have shown that MFN2, which its alterations have been associated with mitochondrial dysfunction, could affect cancer initiation and progression. In fact, it showed that MFN2 may have a double-edged sword effect on cancer fate. Precisely, it demonstrated that MFN2, as a tumor suppressor, induces cancer cell apoptosis and inhibits cell proliferation via Ca²⁺ and Bax-mediated apoptosis and increases P21 and p27 levels, respectively. It also could suppress cell survival via inhibiting PI3K/Akt, Ras-ERK1/2-cyclin D1 and mTORC2/Akt signaling pathways. On the other hand, MFN2, as an oncogene, could increase cancer invasion via snail-mediated epithelial-mesenchymal transition (EMT) and in vivo tumorigenesis. While remarkable progress has been achieved in recent decades, further exploration is required to elucidate whether MFN2 could be a friend or it's an enemy. This study aimed to highlight the different functions of MFN2 in various cancers.

Exercise and Metformin Intervention Prevents Lipotoxicity-Induced Hepatocyte Apoptosis by Alleviating Oxidative and ER Stress and Activating the AMPK/Nrf2/HO-1 Signaling Pathway in db/db Mice

Objective

Nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes (T2DM) commonly coexist and act synergistically to drive adverse clinical outcomes. This study is aimed at investigating the effects of exercise intervention and oral hypoglycaemic drug of metformin (MET) alone or combined on hepatic lipid accumulation. To investigate if oxidative stress and endoplasmic reticulum stress (ERS) are involved in lipotoxicity-induced hepatocyte apoptosis in diabetic mice and whether exercise and/or MET alleviated oxidative stress or ERS-apoptosis by AMPK-Nrf2-HO-1 signaling pathway.

Methods

Forty db/db mice with diabetes (random blood glucose ≥ 250 mg/dL) were randomly allocated into four groups: control (CON), exercise training alone (EX), metformin treatment alone (MET), and exercise combined with metformin (EM) groups. Hematoxylin-eosin and oil red O staining were carried out to observe hepatic lipid accumulation. Immunohistochemical and TUNEL methods were used to detect the protein expression of the binding immunoglobulin protein (BiP) and superoxide dismutase-1 (SOD1) and the apoptosis level of hepatocytes. ERS-related gene expression and the AMPK-Nrf2-HO-1 signaling pathway were tested by western blotting.

Results

Our data showed that db/db mice exhibited increased liver lipid accumulation, which induced oxidative and ER stress of the PERK-eIF2α-ATF4 pathway, and hepatocyte apoptosis. MET combined with exercise training significantly alleviated hepatic lipid accumulation by suppressing BiP expression, the central regulator of ER homeostasis, and its downstream PERK-eIF2α-ATF4 pathway, as well as upregulated the AMPK-Nrf2-HO-1 signaling pathway. Moreover, the combination of exercise and MET displayed protective effects on hepatocyte apoptosis by downregulating Bax expression and TUNEL-positive staining, restoring the balance of cleaved-caspase-3 and caspase-3, and improving the antioxidant defense system to prevent oxidative damage in db/db mice.

Conclusion

Compared to MET or exercise intervention alone, the combined exercise and metformin exhibited significant effect on ameliorating hepatic steatosis, inhibiting oxidative and ER stress-induced hepatocyte apoptosis via improving the capacity of the antioxidant defense system and suppression of the PERK-eIF2α-ATF4 pathway. Furthermore, upregulation of AMPK-Nrf2-HO-1 signaling pathway might be a key crosstalk between MET and exercise, which may have additive effects on alleviating hepatic lipid accumulation.

Endoplasmic reticulum-mitochondria miscommunication is an early and causal trigger of hepatic insulin resistance and steatosis

BACKGROUND & AIMS

Hepatic insulin resistance in obesity and type 2 diabetes was recently associated with endoplasmic reticulum (ER)-mitochondria miscommunication. These contact sites (mitochondria-associated membranes: MAMs) are highly dynamic and involved in many functions; however, whether MAM dysfunction plays a causal role in hepatic insulin resistance and steatosis is not clear. Thus, we aimed to determine whether and how organelle miscommunication plays a role in the onset and progression of hepatic metabolic impairment.

METHODS

We analyzed hepatic ER-mitochondria interactions and calcium exchange in a time-dependent and reversible manner in mice with diet-induced obesity. Additionally, we used recombinant adenovirus to express a specific organelle spacer or linker in mouse livers, to determine the causal impact of MAM dysfunction on hepatic metabolic alterations.

RESULTS

Disruption of ER-mitochondria interactions and calcium exchange is an early event preceding hepatic insulin resistance and steatosis in mice with diet-induced obesity. Interestingly, an 8-week reversal diet concomitantly reversed hepatic organelle miscommunication and insulin resistance in obese mice. Mechanistically, disrupting structural and functional ER-mitochondria interactions through the hepatic overexpression of the organelle spacer FATE1 was sufficient to impair hepatic insulin action and glucose homeostasis. In addition, FATE1-mediated organelle miscommunication disrupted lipid-related mitochondrial oxidative metabolism and induced hepatic steatosis. Conversely, reinforcement of ER-mitochondria interactions through hepatic expression of a synthetic linker prevented diet-induced glucose intolerance after 4 weeks' overnutrition. Importantly, ER-mitochondria miscommunication was confirmed in the liver of obese patients with type 2 diabetes, and correlated with glycemia, HbA1c and HOMA-IR index.

CONCLUSIONS

ER-mitochondria miscommunication is an early causal trigger of hepatic insulin resistance and steatosis, and can be reversed by switching to a healthy diet. Thus, targeting MAMs could help to restore metabolic homeostasis.

LAY SUMMARY

The literature suggests that interactions between the endoplasmic reticulum and mitochondria could play a role in hepatic insulin resistance and steatosis during chronic obesity. In the present study, we reappraised the time-dependent regulation of hepatic endoplasmic reticulum-mitochondria interactions and calcium exchange, investigating reversibility and causality, in mice with diet-induced obesity. We also assessed the relevance of our findings to humans. We show that organelle miscommunication is an early causal trigger of hepatic insulin resistance and steatosis that can be improved by nutritional strategies.

Nonalcoholic Fatty Liver Disease and Hypothyroidism: What You Need to Know

Non-alcoholic fatty liver disease (NAFLD) represents one of the leading causes of chronic liver disease globally, perhaps because of the drastic increase in prevalence around the world during the last 20 years and continues growing. The disease starts from simple steatosis (NAFL) that can progress to non-alcoholic steatohepatitis (NASH) and, in some patients, progress to cirrhosis and hepatocellular carcinoma (HCC). The pathogenesis and pathophysiology of NAFLD are complex and involve different factors (genetic, metabolic, endocrinopathies, and others). One of the concerns that appeared in recent years is hypothyroidism-induced NAFLD. The pathogenesis is compound and not well understood, and an association between hypothyroidism and NAFLD remains controversial because of insufficient studies that can confirm it. More research is needed to determine the association between hypothyroidism and NAFLD and the underlying mechanisms. In this review, we will discuss a more in-depth analysis of the physiology of thyroid hormones (TH) as well as the pathophysiology of hypothyroidism-induced NAFLD and, based on the recent meta-analyses, the association of thyroid hormones and NAFLD.

Downregulation of hepatic fat accumulation, inflammation and fibrosis by nerolidol in purpose built western-diet-induced multiple-hit pathogenesis of NASH animal model

Western diet style (fast food), which includes fatty frozen junk food, lard, processed meats, whole-fat dairy foods, cream, mayonnaise, butter, snacks, and fructose, is a primary etiological determinant for developing nonalcoholic steatohepatitis (NASH) worldwide. Here the primary focus is to see the impact of naturally identified essential oil on disease mechanisms developed in an animal model using the same ingredients. Currently, symptomatic therapies are recommended for the management of NASH due to non-availability of specific treatments. Therefore, the present study was designed to evaluate the potential anti-NASH effect of nerolidol in a rat model fed with a purpose-built diet. The diet substantially induced insulin resistance, hepatic steatosis, dyslipidemia, and elevation of liver enzymes in the experimental animals. The levels of liver oxidative stress markers, nitrites (NO₂^-), serum pro-inflammatory cytokine (TNF-α) and hepatic collagen were increased in disease control rats. Nerolidol oral treatment in ascending dose order of 250 and 500 mg/kg substantially reduced the steatosis (macrovesicular and microvesicular), degeneration of hepatocytes, and inflammatory cells infiltration. The amounts of circulatory TNF-α and tissue collagen were also reduced at 500 mg/kg dose of nerolidol, expressing its anti-fibrotic effect. The current study described the multiple-hit pathophysiology of NASH as enhanced steatosis, pro-inflammatory markers, and oxidative stress in rats, which resulted in the development of vicious insulin resistance. Nerolidol treatment significantly reduced hepatic lipid accumulation and halted disease progression induced by a hypercaloric diet.

Adverse Effects of Perfluorooctane Sulfonate on the Liver and Relevant Mechanisms

Perfluorooctane sulfonate (PFOS) is a persistent, widely present organic pollutant. PFOS can enter the human body through drinking water, ingestion of food, contact with utensils containing PFOS, and occupational exposure to PFOS, and can have adverse effects on human health. Increasing research shows that the liver is the major target of PFOS, and that PFOS can damage liver tissue and disrupt its function; however, the exact mechanisms remain unclear. In this study, we reviewed the adverse effects of PFOS on liver tissue and cells, as well as on liver function, to provide a reference for subsequent studies related to the toxicity of PFOS and liver injury caused by PFOS.

Protective Effects of Tiaoganquzhi Decoction in Treating inflammatory Injury of Nonalcoholic Fatty liver Disease by Promoting CGI-58 and Inhibiting Expression of NLRP3 Inflammasome

Tiaoganquzhi Decoction (TGQZD) is a traditional Chinese herbal formulation demonstrated to be a clinically effective treatment for nonalcoholic fatty liver disease (NAFLD), although details concerning its clinical mechanism are poor. This study aimed to explore the mechanism of TGQZD on improvement of inflammatory damage and dyslipidemia caused by NAFLD through the CGI-58/ROS/NLRP3 inflammasome pathway. In our research, the in vivo protective effects of TGQZD on HFD-induced liver injury in rats and in vitro using lipopolysaccharide (LPS)+palmitate (PA)-stimulated HepG-2 cells model. Histological changes were evaluated by hematoxylin-eosin and Oil Red O staining. Inflammatory cytokines and protein expression were analyzed by ELISA, Real time PCR and western blotting. Liver function, blood lipids, free fatty acids (FFA), and reactive oxygen species (ROS) were determined by biochemical detection. Our results indicated that TGQZD exhibited anti-inflammatory activity, reduced the severity of NAFLD and ameliorated the pathological changes. Further, TGQZD improved liver function and lipid metabolism in NAFLD rats. TGQZD lowered serum aspartate aminotransferase, alanine aminotransferase, triglyceride, and total cholesterol levels. TGQZD suppressed the formulation of FFA and ROS. It also reduced the expression and release of the inflammatory cytokine interleukin-1β by promoting CGI-58 expression and inhibiting the expression of FFA, TNF-α, and the NLRP3 inflammasome induced by ROS. TGQZD exhibited anti-inflammatory effects via the CGI-58, ROS and NLRP3 inflammasome pathway in vivo and in vitro, respectively. Our findings demonstrated that TGQZD is a useful and effective therapeutic agent for treating NAFLD via promotion of CGI-58 to inhibit the expression of ROS-induced NLRP3 inflammasome.

Physical exercise positively modulates nonalcoholic steatohepatitis-related hepatic endoplasmic reticulum stress

Obesity is a predictive factor for the development of nonalcoholic steatohepatitis (NASH). Although some of the mechanisms associated with NASH development are still elusive, its pathogenesis relies on a complex broad spectrum of (interconnected) metabolic-based disorders. We analyzed the effects of voluntary physical activity (VPA) and endurance training (ET), as preventive and therapeutic nonpharmacological strategies, respectively, against hepatic endoplasmic reticulum (ER) stress, ER-related proapoptotic signaling, and oxidative stress in an animal model of high-fat diet (HFD)-induced NASH. Adult male Sprague-Dawley rats were divided into standard control liquid diet (SCLD) or HFD groups, with sedentary, VPA, and ET subgroups in both (sedentary animals with access to SCLD [SS], voluntarily physically active animals with access to SCLD [SV], and endurance-trained animals with access to SCLD [ST] in the former and sedentary animals with access to liquid HFD [HS], voluntarily physically active animals with access to liquid HFD [HV], and endurance-trained animals with access to liquid HFD [HT] in the latter, respectively). Hepatic ER stress and ER-related proapoptotic signaling were evaluated by Western blot and reverse transcriptase-polymerase chain reaction; redox status was evaluated through quantification of lipid peroxidation, protein carbonyls groups, and glutathione levels as well as antioxidant enzymes activity. In SCLD-treated animals, VPA significantly decreased eukaryotic initiation factor-2 alpha (eIF2α). In HFD-treated animals, VPA significantly decreased eIF2α and phospho-inositol requiring enzyme-1 alpha (IRE1α) but ET significantly decreased eIF2α and significantly increased both spliced X-box binding protein 1 (sXBP1) and unspliced X-box binding protein 1; a significant increase of phosphorylated-eIF2α (p-eIF2α) to eIF2α ratio occurred in ET versus VPA. HS compared to SS disclosed a significant increase of total and reduced glutathione, HV compared to SV a significant increase of oxidized glutathione, HT compared to ST a significant increase of p-eIF2α to eIF2α ratio and sXBP1. Physical exercise counteracts NASH-related ER stress and its associated deleterious consequences through a positive and dynamical modulation of the hepatic IRE1α-X-box binding protein 1 pathway.

β-cell mitochondria in diabetes mellitus: a missing puzzle piece in the generation of hPSC-derived pancreatic β-cells?

Diabetes mellitus (DM), currently affecting 463 million people worldwide is a chronic disease characterized by impaired glucose metabolism resulting from the loss or dysfunction of pancreatic β-cells with the former preponderating in type 1 diabetes (T1DM) and the latter in type 2 diabetes (T2DM). Because impaired insulin secretion due to dysfunction or loss of pancreatic β-cells underlies different types of diabetes, research has focused its effort towards the generation of pancreatic β-cells from human pluripotent stem cell (hPSC) as a potential source of cells to compensate for insulin deficiency. However, many protocols developed to differentiate hPSCs into insulin-expressing β-cells in vitro have generated hPSC-derived β-cells with either immature phenotype such as impaired glucose-stimulated insulin secretion (GSIS) or a weaker response to GSIS than cadaveric islets. In pancreatic β-cells, mitochondria play a central role in coupling glucose metabolism to insulin exocytosis, thereby ensuring refined control of GSIS. Defects in β-cell mitochondrial metabolism and function impair this metabolic coupling. In the present review, we highlight the role of mitochondria in metabolism secretion coupling in the β-cells and summarize the evidence accumulated for the implication of mitochondria in β-cell dysfunction in DM and consequently, how targeting mitochondria function might be a new and interesting strategy to further perfect the differentiation protocol for generation of mature and functional hPSC-derived β-cells with GSIS profile similar to human cadaveric islets for drug screening or potentially for cell therapy.

HIIT and MICT attenuate high-fat diet-induced hepatic lipid accumulation and ER stress via the PERK-ATF4-CHOP signaling pathway

Fatty liver can be induced by dietary habits and lifestyle and is directly related to obesity. Although the benefits of exercise interventions for reduction of liver fat have recently been acknowledged, the underlying mechanisms remain unclear. Thus, our present study investigated the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on high-fat diet-induced hepatic lipid accumulation, and explored the role of endoplasmic reticulum (ER) stress signaling pathways. To establish an obesity model, rats were fed with a normal standard diet or a high-fat diet (45% kcal as fat). Then, both lean and obese rats were divided into three subgroups: sedentary control (LC, OC) groups, high-intensity interval training (LHI, OHI) groups, and moderated-intensity continuous training (LMI, OMI) groups (n = 10). Rats in the exercise group underwent a swimming training protocol for 8 weeks. After the experimental period, serum and liver tissues from different groups were dissected for morphological and biochemical analyses. The results showed that with HIIT and MICT interventions, body weight and serum inflammatory markers (e.g., MCP-1, IL-1β, and TNF-α) were reduced in obese rats. Interestingly, HIIT was more effective in ameliorating liver triglyceride content and enhancing mitochondrial metabolic-enzymatic activity than was MICT in obese rats. Both HIIT and MICT conferred beneficial properties through upregulating Nrf2 expression, improving antioxidant enzyme activities and reduction of hepatic ER stress, which may have been regulated by the Bip-mediated PERK-ATF4-CHOP pathway. In conclusion, our findings confirmed the effectiveness of HIIT and MICT, particularly HIIT, in mitigating hepatic lipid accumulation.

Potential role of mitochondria-associated endoplasmic reticulum membrane proteins in diseases

Mitochondria-associated endoplasmic reticulum membranes (MAMs) are dynamic membrane coupling regions formed by the coupling of the mitochondrial outer membrane and endoplasmic reticulum (ER). MAMs are involved in the mitochondrial dynamics, mitophagy, Ca²⁺ exchange, and ER stress. A large number of studies indicate that many proteins are involved in the formation of MAMs, including dynamic-related protein 1 (Drp1), DJ-1, PTEN-induced putative kinase 1 (PINK), α-synuclein (α-syn), sigma-1 receptor (S1R), mitofusin-2 (Mfn2), presenilin-1 (PS1), protein kinase R (PKR)-like ER kinase (PERK), Parkin, Cyclophilin D (CypD), glucose-related protein 75 (Grp75), FUN14 domain containing 1 (Fundc1), vesicle-associated membrane-protein-associated protein B (VAPB), phosphofurin acidic cluster sorting protein 2 (PACS-2), ER oxidoreductin 1 (Ero1), and receptor expression-enhancing protein 1 (REEP1). These proteins play an important role in the structure and functions of the MAMs. Abnormalities in these MAM proteins further contribute to the occurrence and development of related diseases, such as neurodegenerative diseases, non-alcoholicfattyliverdisease (NALFD), type 2 diabetes mellitus (T2DM), and diabetic kidney (DN). In this review, we introduce important proteins involved in the structure and the functions of the MAMs. Furthermore, we effectively summarize major insights about these proteins that are involved in the physiopathology of several diseases through the effect on MAMs.

Perspectives in liver redox imbalance: Toxicological and pharmacological aspects underlying iron overloading, nonalcoholic fatty liver disease, and thyroid hormone action

Oxidative stress is an imbalance between oxidants and antioxidants in favor of the oxidants, leading to a disruption of redox signaling and control, and/or molecular damage altering cellular functions. This redox imbalance may trigger different responses depending on the antioxidant potential of a given cell, the level of reactive oxygen/nitrogen species (ROS/RNS) attained and the time of exposure, with protective effects being induced at low ROS/RNS levels in acute or short-term conditions, and harmful effects after high ROS/RNS exposure in prolonged situations. Relevant conditions underlying liver redox imbalance include iron overload associated with ROS production via Fenton chemistry and the magnitude of the iron labile pool achieved, with low iron exposure inducing protective effects related to nuclear factor-κB, signal transducer and activation of transcription 3, and nuclear factor erythroid-related factor 2 (Nrf2) activation and upregulation of ferritin, hepcidin, acute-phase response and antioxidant components, whereas high iron exposure causes drastic oxidation of biomolecules, mitochondrial dysfunction, and cell death due to necrosis, apoptosis and/or ferroptosis. Redox imbalance in nonalcoholic fatty liver disease (NAFLD) is related to polyunsaturated fatty acid depletion, lipogenic factor sterol regulatory element-binding protein-1c upregulation, fatty acid oxidation-dependent peroxisome proliferator-activated receptor-α downregulation, low antioxidant factor Nrf2 and insulin resistance, a phenomenon that is exacerbated in nonalcoholic steatohepatitis triggering an inflammatory response. Thyroid hormone (T₃ ) administration determines liver preconditioning against ischemia-reperfusion injury due to the redox activation of several transcription factors, AMP-activated protein kinase, unfolded protein response and autophagy. High grade liver redox imbalance occurring in severe iron overload is adequately handled by iron chelation, however, that underlying NAFLD/NASH is currently under study in several Phase II and Phase III trials.