Mitochondrial adaptations and dysfunctions in nonalcoholic fatty liver disease

Generation and characterization of a chronic in vitro model to study the early stage of metabolic dysfunction-associated steatotic liver disease (MASLD)

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a chronic and progressive liver disease with an increasing global burden that starts with an early stage of simple steatosis (MASL) which frequently progresses to liver cirrhosis and hepatocellular carcinoma (HCC). Despite its widespread occurrence, the MASL or steatotic stage, characterized by excessive fat accumulation in the liver and considered reversible and benign, has not been extensively studied. To study MASL effectively, it is imperative to have a clinically relevant model system that focuses solely on steatosis, in a progressive and time-dependent manner, recapitulating molecular changes associated with human disease. We established a chronic cellular model of MASL using a primary immortalized human hepatocyte cell line treated with a low dose mixture of fatty acids. This model mimics the pattern of chronic disease progression, shows minimal lipotoxicity, exhibits progressive lipid accumulation (from early to moderate steatosis), and demonstrates macrosteatosis, a hallmark of MASL. To determine whether this model recapitulates both morphological and molecular aspects of steatosis, we measured the expression of key genes and pathways found to be dysregulated in a recently available early MASL patient dataset as well as a non-human primate model of MASL. In support of the relevance of our model, we observed increased fatty acid uptake, lipogenesis, mitochondrial activity, metabolic rewiring, and autophagic alterations that significantly overlap with the pathological features of human and non-human primate MASL. In conclusion, we generate a relevant cellular model of steatosis that can serve as a robust platform for screening of existing chemical libraries to identify potent inhibitors of MASL as well as discovering novel therapeutic targets by mechanistically studying altered molecular signatures associating early stages of MASLD.

Mitochondrial viscosity, oxidative stress and autophagy responsive fluorescent Zn(II) complex for monitoring non-alcoholic fatty liver disease

Accumulating evidence highlights the critical role of dysfunctional mitochondrial quality control in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). However, there is limited information available regarding of viscosity-related cellular metabolic processes of NAFLD. To address this, we developed a novel viscosity-sensitive fluorescent metal Zn(II) complex, LIFM-ZY-1, for monitoring viscosity changes with one-photon (OP) and two-photon (TP) fluorescence. It could effectively track cellular oxidative stress induced by lipotoxicity with viscosity changes, as reflected by viscosity changes in the OP/TP channel. Besides, LIFM-ZY-1 was capable of detecting non-selective mitophagy triggered by starvation in real time and selective mitophagy induced by autophagy drug rapamycin. Moreover, LIFM-ZY-1 successfully monitored the deterioration and therapeutic outcome of NAFLD mice with changing viscosity induced by overeating and autophagy drug empagliflozin. Overall, our findings demonstrated the potential of LIFM-ZY-1 as a valuable tool for real time monitoring NAFLD treatment through viscosity, oxidative stress and autophagy changes, offering valuable insights into the underlying biological processes and potential therapeutic strategies for NAFLD.

Neurotensin promotes hepatic steatosis by regulating lipid uptake and mitochondrial adaptation in hepatocytes

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a multifactorial disease characterized by hepatic steatosis. Mitochondrial dysfunction resulting in the incomplete digestion of surplus fat is one of the key factors that lead to hepatic steatosis but the reason for this remains unclear. We investigated the role of neurotensin (NTS), a gut hormone, in inducing maladaptive fat metabolism in steatotic liver. We identify CD36 and PGC1α, two critical drivers of MASLD, as direct NTS signaling targets in the liver. NTS upregulates CD36, a free fatty acid receptor, in hepatocytes and promotes long chain lipid uptake. Conversely, NTS inhibits PGC1α, which acts as a lipid sensor and translocates to the nucleus to activate lipid catabolism-related genes in an AMPK-dependent manner. Thus, a high fat diet decreases the fatty acid oxidation and oxidative phosphorylation capacity of the liver and hepatocytes from NTS or NTS receptor 1 (NTSR1) wild type mice; whereas NTS deficiency preserves the lipid metabolism capacity of the liver. NTS signaling is significantly upregulated in MASLD and in metabolic dysfunction-associated steatohepatitis (MASH) human liver samples when compared to normal livers, which correlates with the expression of CD36 and oxidative phosphorylation proteins. These findings provide critical mechanistic insights into the maladaptive fat metabolism noted with steatosis in mice and humans and suggest novel strategies for therapeutic intervention of MASLD, which affects nearly one-quarter of the global population.

Ultrasound-driven ROS-scavenging nanobubbles for synergistic NASH treatment via FXR activation

Non-alcoholic steatohepatitis (NASH) pathogenesis is primarily driven by lipotoxicity-induced oxidative stress and inflammation, yet effective treatments remain challenging to identify. In this work, a novel therapeutic approach was introduced via a ultrasound (US) -driven, reactive oxygen species (ROS) -scavenging and liver-targeted nanobubbles system, termed Apt-DTP-NBs@RSV@OCA, which co-encapsulated resveratrol (RSV) and obeticholic acid (OCA). This system provides a safe and efficient platform for specifically delivering these agents to the liver in the context of the NASH therapy. The synthesized nanobubbles showed a spherical morphology with an average diameter of 165 ± 6.05 nm, whose encapsulation efficiencies of approximately 93 % for RSV and 90 % for OCA were achieved. These nanobubbles exhibited the enhanced targeting and accumulation within NASH affected cells and the excellent biocompatibility in cytotoxicity experiments. Subsequently, in vitro assessments using HepG2 cells, Apt-DTP-NBs@RSV@OCA improved lipid metabolism and reduced ROS levels. It was also showed in vivo experiments in mice that the hepatic targeting of Apt-DTP-NBs@RSV@OCA increased their effective concentration within the liver. In addition, the hepatic-targeting and ultrasound-driving Apt-DTP-NBs@RSV@OCA nanocarriers enhanced the cellular uptake of RSV and OCA in a NASH cell model and improved ROS-scavenging capabilities. Meanwhile, these nanocarriers modulated lipid metabolism (triglycerides, total cholesterol), inflammatory cytokine metabolism (IL-4, IL-10, IL-15, TNF-α) and oxidative stress levels (SOD, MDA). Furthermore, mechanistic studies revealed that Apt-DTP-NBs@RSV@OCA activated the FXR/SHP signaling pathway, enhanced FoxO1 activity, and alleviated lipid accumulation, inflammation, and oxidative stress. In summary, these findings suggest that Apt-DTP-NBs@RSV@OCA pave a promising way for the treatment of NASH.

Prevotella-Produced Succinate Alleviates Hepatic Steatosis by Enhancing Mitochondrial Function in Layer-Type Chickens

BACKGROUND

A higher abundance of Prevotella species in the gut microbiota is associated with the consumption of high-fiber diets and can be reproduced by dietary supplementation with L-arabinose. The effect of Prevotella and its metabolite succinate on hepatic lipid metabolism remains unclear.

OBJECTIVES

This study aimed to elucidate the effects of Prevotella and its metabolite succinate on hepatic steatosis in layer-type pullets.

METHODS

In experiment 1, 4-wk-old female layer-type chickens (Isa Brown) were randomly divided into 4 dietary groups and fed a basal diet supplemented with 0%, 2%, 4%, or 6% L-arabinose for 11 wk. In experiments 2 and 3, 10-wk-old chickens were orally administered Prevotella (106 CFU) or fed a diet supplemented with 0.2% sodium succinate for 4 wk. The growth performance, plasma lipid metabolites, hepatic lipid accumulation and gene expression, and cecal microbiota were determined. In in vitro experiment, chicken embryo hepatocytes were treated with Prevotella's metabolites or 0.1 mM succinate in the absence or presence of 4c, a succinate receptor 1 (SUCNR1) inhibitor, or shRNA-PGC1β. Lipid deposition and mitochondrial function were measured. Data were analyzed with a 1-way analysis of variance followed by Tukey's test.

RESULTS

L-arabinose decreased (-68%) hepatic and plasma TG (-52%) and enhanced the abundance of cecal Prevotella (+45-fold) (P < 0.001). Oral administration of Prevotella melaninogenica reduced plasma TG (-22%, P < 0.05) and increased succinate (+66%, P < 0.01). Succinate feeding reduced hepatic (-51%, P < 0.001) and plasma TG (-40%, P < 0.05). Both Prevotella and succinate administration reduced fatty acid synthase (FAS) activity with the induction of mitochondrial function-associated proteins. In vitro experiments showed that Prevotella and succinate alter mitochondrial function and lipid metabolism via SUCNR1, wherein PGC1β plays a critical role.

CONCLUSIONS

Succinate produced by Prevotella is a likely metabolite that reduces hepatic lipid deposition by suppressing FAS activity and activating mitochondrial function.

Furan fatty acids supplementation in obese mice reverses hepatic steatosis and protects against cartilage degradation

Obesity is a major global health problem associated with numerous metabolic dysfunctions, an increased risk of developing Metabolic Associated Steatotic Liver Disease (MASLD) and osteoarthritis. Recently, we demonstrated that in Diet-induced-Obesity (DIO) mouse model, preventive furan fatty acids (FuFA-F2) supplementation, a natural compounds found in many foods, reduced the onset of metabolic disorders and increased muscle mass. Here, we aimed to determine whether a short FuFA-F2 supplementation is capable of providing beneficial health effects in obese mice, notably by reversing metabolic disorders and limiting cartilage degradation. 6-month-old obese C57Bl/6 J mice were fed for four additional weeks on a high-fat and high-sucrose (HFHS) diet, supplemented or not with FuFA-F2 (40 mg/day/kg of body weight). Liver triglyceride content and histologic analysis revealed that 4 weeks of FuFA-F2 supplementation fully reversed hepatic steatosis in obese mice. Liver RNA-sequencing analysis highlighted that FuFA-F2 partly reversed the gene expression signature induced by the HFHS diet and favorably changed the expression of many genes known to be involved in the development of hepatic steatosis such as Pcsk9, Stard4, Insig1 and Sulf2. We also found that FuFA-F2 supplementation increased skeletal muscle mass and protected against cartilage degradation and synovitis induced by obesity. Our findings demonstrated that FuFA-F2 supplementation for 4 weeks in obese mice was enough to reverse the development of MASLD, promote an increase in skeletal muscle mass and protect against cartilage degradation induced by the HFHS diet. This study highlights that nutritional supplementation with FuFA-F2 could be an effective approach to treat obesity-related disorders.

Correlation of organelle interactions in the development of non-alcoholic fatty liver disease

Organelles, despite having distinct functions, interact with each other. Interactions between organelles typically occur at membrane contact sites (MCSs) to maintain cellular homeostasis, allowing the exchange of metabolites and other pieces of information required for normal cellular physiology. Imbalances in organelle interactions may lead to various pathological processes. Increasing evidence suggests that abnormalorganelle interactions contribute to the pathogenesis of non-alcoholic fatty liver disease (NAFLD). However, the key role of organelle interactions in NAFLD has not been fully evaluated and researched. In this review, we summarize the role of organelle interactions in NAFLD and emphasize their correlation with cellular calcium homeostasis, lipid transport, and mitochondrial dynamics.

Butyrate Regulates Intestinal DNA Virome and Lipopolysaccharide Levels to Prevent High-Fat Diet-Related Liver Damage in Rats

As the adsorption receptor of bacteriophage tail protein, bacterial lipopolysaccharide (LPS) is a main culprit responsible for nonalcoholic fatty liver disease (NAFLD) caused by high-fat diets. However, few studies have focused on how the interaction between intestinal bacteriophages and bacterial LPS affects the development and progression of NAFLD. Herein, we determined that excessive fat intake significantly increases the levels of endogenous LPS, while the administration of beneficial metabolites of the intestinal microbiota (specifically butyrate) alleviated hepatic injury in rats. The beneficial mechanism of butyrate was attributed to the reprogramming of the structure of the intestinal DNA virome (primarily, phageome). Butyrate possesses the potential to augment bacteriophagic microbial diversity, thereby potentially facilitating interactions between intestinal bacteriophages and bacterial LPS (in the case of homologous phage), further improving mitochondrial dysfunction and reactive oxygen species production, which, in turn, lowered HepG2 cell damage. Likewise, fecal phage transplantation further confirmed that intestinal phages from rats that received butyrate could effectively interact with bacterial LPS to reduce liver damage in rats. Taken together, modifying the intestinal phageome is a promising treatment option for high-fat diet-related NAFLD.

The Warburg hypothesis and the emergence of the mitochondrial metabolic theory of cancer

Otto Warburg originally proposed that cancer arose from a two-step process. The first step involved a chronic insufficiency of mitochondrial oxidative phosphorylation (OxPhos), while the second step involved a protracted compensatory energy synthesis through lactic acid fermentation. His extensive findings showed that oxygen consumption was lower while lactate production was higher in cancerous tissues than in non-cancerous tissues. Warburg considered both oxygen consumption and extracellular lactate as accurate markers for ATP production through OxPhos and glycolysis, respectively. Warburg's hypothesis was challenged from findings showing that oxygen consumption remained high in some cancer cells despite the elevated production of lactate suggesting that OxPhos was largely unimpaired. New information indicates that neither oxygen consumption nor lactate production are accurate surrogates for quantification of ATP production in cancer cells. Warburg also did not know that a significant amount of ATP could come from glutamine-driven mitochondrial substrate level phosphorylation in the glutaminolysis pathway with succinate produced as end product, thus confounding the linkage of oxygen consumption to the origin of ATP production within mitochondria. Moreover, new information shows that cytoplasmic lipid droplets and elevated aerobic lactic acid fermentation are both biomarkers for OxPhos insufficiency. Warburg's original hypothesis can now be linked to a more complete understanding of how OxPhos insufficiency underlies dysregulated cancer cell growth. These findings can also address several questionable assumptions regarding the origin of cancer thus allowing the field to advance with more effective therapeutic strategies for a less toxic metabolic management and prevention of cancer.

Early-life exposure to gestational diabetes mellitus predisposes offspring to pediatric nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has emerged as the prevailing chronic liver disease in the pediatric population due to the global obesity pandemic. Evidence shows that prenatal and postnatal exposure to maternal abnormalities leads to a higher risk of pediatric NAFLD through persistent alterations in developmental programming. Gestational diabetes mellitus (GDM) is a hyperglycemic syndrome which has become the most prevalent complication in pregnant women. An increasing number of both epidemiologic investigations and animal model studies have validated adverse and long-term outcomes in offspring following GDM exposure in utero. Similarly, GDM is considered a crucial risk factor for pediatric NAFLD. This review aimed to summarize currently published studies concerning the inductive roles of GDM in offspring NAFLD development during childhood and adolescence. Dysregulations in hepatic lipid metabolism and gut microbiota in offspring, as well as dysfunctions in the placenta are potential factors in the pathogenesis of GDM-associated pediatric NAFLD. In addition, potentially effective interventions for GDM-associated offspring NAFLD are also discussed in this review. However, most of these therapeutic approaches still require further clinical research for validation.

A mitochondria-targeted fluorescent probe based on an anti-diffusion strategy for in situ imaging of fatty liver, inflammation and cancer

Abnormal mitochondrial viscosity is closely associated with a wide range of diseases and cellular dysfunction. It is crucial to develop fluorescent probes for precisely monitoring changes of mitochondrial viscosity in the detection and treatment of associated diseases. However, mitochondria-targeted fluorescent probes currently faced off-target problems because their high water-solubility could hinder the accurate detection of mitochondrial viscosity. Herein, a viscosity-sensitive fluorescent probe, HPQ-MV was designed and synthesized in this work. The indole cation and HPQ (2-(2'-hydroxyphenyl)-4(3H)-quinazolinone) moiety were introduced could make the probe HPQ-MV have excellent mitochondrial targeting properties and reduce the aqueous solubility of HPQ-MV made the probe less susceptible to diffusion, respectively. When the mitochondrial membrane potential was decreased, HPQ-MV could remain stable in the mitochondria and not cause false-negative signals. HPQ-MV had a signal-to-noise ratio of up to 2900-fold with respect to viscosity which was unaffected by pH and polarity. Additionally, HPQ-MV possessed a tissue permeability of up to 62.6 μM and had effectively facilitated in vivo imaging of fatty liver, inflammation, and in situ tumors.

N6-Methyladenosine Modification in the Metabolic Dysfunction-Associated Steatotic Liver Disease

Epigenetics of N6-methyladenine (m6A) modification may play a key role during the regulation of various diseases, including metabolic dysfunction-associated steatotic liver disease (MASLD). The m6A modification has been shown to be accomplished via the exploitation of several players such as methyltransferases, demethylases, and/or methylation-binding molecules. Significantly, the m6A methylation can regulate the key eukaryotic transcriptome by affecting the subcellular localization, splicing, export, stability, translation, and decay of those RNAs. An increasing amount of data has designated that the m6A modification of RNAs can also modulate the expression of autophagy-related genes, which could also control the autophagy in hepatocytes. Oxidative stress with reactive oxygen species (ROS) can induce m6A RNA methylation, which might be associated with the regulation of mitochondrial autophagy (mitophagy) and/or the development of MASLD. Therefore, both autophagy and the m6A modification could play important roles in regulating the pathogenesis of MASLD. Comprehending the relationship between m6A and mitophagy may be helpful for the development of future therapeutic strategies against MASLD. This review would advance the understanding of the regulatory mechanisms of m6A RNA modification, focusing on the impact of mitochondrial dysregulation and mitophagy in the liver with MASLD.

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.

Flutamide Promotes Early Hepatocarcinogenesis Through Mitophagy in High-Fat Diet-Fed Non-Obese Steatotic Rats

Flutamide (FL), a non-steroidal drug used for its antiandrogenic, anticancer, and disrupting endocrine properties, induces mitochondrial toxicity and drug metabolism enzymes and promotes hepatocarcinogenesis. The inhibition of mitophagy, leading to the accumulation of damaged mitochondria, is implicated in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). In this study, we investigated the effects of FL in high-fat diet (HFD)-induced non-obese steatosis rats, categorized into four groups: basal diet (BD), BD + FL, HFD, and HFD + FL. The FL exacerbated HFD-induced steatosis and marginally increased preneoplastic lesions. To analyze hepatic preneoplastic lesions, we divided them into clusters based on the expression ratios of the mitophagy regulators LC3 and AMBRA1. The expression rates of LC3 and AMBRA1 in these precancerous lesions were classified into three clusters using k-means clustering. The HFD group exhibited an increased ratio of mitophagy inhibition clusters, as indicated by decreased LC3 and increased AMBRA1 levels in background hepatocytes and preneoplastic lesions. FL counteracted HFD-mediated mitophagy inhibition, as indicated by increased LC3 and decreased AMBRA1 levels in background hepatocytes. Our clustering analysis revealed that FL-induced mitophagy induction relied on Parkin expression. The present study underscores the significance of cluster analysis in understanding the role of mitophagy within small preneoplastic lesions and suggests that FL may potentially exacerbate NAFLD-associated hepatocarcinogenesis by affecting mitophagy.

Mitochondrial mt12361A>G increased risk of metabolic dysfunction-associated steatotic liver disease among non-diabetes

BACKGROUND

Insulin resistance, lipotoxicity, and mitochondrial dysfunction contribute to the pathogenesis of metabolic dysfunction-associated steatotic liver disease (MASLD). Mitochondrial dysfunction impairs oxidative phosphorylation and increases reactive oxygen species production, leading to steatohepatitis and hepatic fibrosis. Artificial intelligence (AI) is a potent tool for disease diagnosis and risk stratification.

AIM

To investigate mitochondrial DNA polymorphisms in susceptibility to MASLD and establish an AI model for MASLD screening.

METHODS

Multiplex polymerase chain reaction was performed to comprehensively genotype 82 mitochondrial DNA variants in the screening dataset (n = 264). The significant mitochondrial single nucleotide polymorphism was validated in an independent cohort (n = 1046) using the Taqman® allelic discrimination assay. Random forest, eXtreme gradient boosting, Naive Bayes, and logistic regression algorithms were employed to construct an AI model for MASLD.

RESULTS

In the screening dataset, only mt12361A>G was significantly associated with MASLD. mt12361A>G showed borderline significance in MASLD patients with 2-3 cardiometabolic traits compared with controls in the validation dataset (P = 0.055). Multivariate regression analysis confirmed that mt12361A>G was an independent risk factor of MASLD [odds ratio (OR) = 2.54, 95% confidence interval (CI): 1.19-5.43, P = 0.016]. The genetic effect of mt12361A>G was significant in the non-diabetic group but not in the diabetic group. mt12361G carriers had a 2.8-fold higher risk than A carriers in the non-diabetic group (OR = 2.80, 95%CI: 1.22-6.41, P = 0.015). By integrating clinical features and mt12361A>G, random forest outperformed other algorithms in detecting MASLD [training area under the receiver operating characteristic curve (AUROC) = 1.000, validation AUROC = 0.876].

CONCLUSION

The mt12361A>G variant increased the severity of MASLD in non-diabetic patients. AI supports the screening and management of MASLD in primary care settings.

The role of extracellular vesicles in non-alcoholic steatohepatitis: Emerging mechanisms, potential therapeutics and biomarkers

Non-alcoholic steatohepatitis (NASH), an emerging global healthcare problem, has become the leading cause of liver transplantation in recent decades. No effective therapies in the clinic have been proven due to the incomplete understanding of the pathogenesis of NASH, and further studies are expected to continue to delve into the mechanisms of NASH. Extracellular vesicles (EVs), which are small lipid membrane vesicles carrying proteins, microRNAs and other molecules, have been identified to play a vital role in cell-to-cell communication and are involved in the development and progression of various diseases. In recent years, there has been increasing interest in the role of EVs in NASH. Many studies have revealed that EVs mediate important pathological processes in NASH, and the role of EVs in NASH is distinct and variable depending on their origin cells and target cells. This review outlines the emerging mechanisms of EVs in the development of NASH and the preclinical evidence related to stem cell-derived EVs as a potential therapeutic strategy for NASH. Moreover, possible strategies involving EVs as clinical diagnostic, staging and prognostic biomarkers for NASH are summarized.

Perinatal obesity primes the hepatic metabolic stress response in the offspring across life span

Perinatal obesity is associated with an increased risk of metabolic diseases and hepatic dysfunction in offspring. However, the underlying mechanisms of this metabolic programming remain incompletely understood. This study aimed to elucidate the influence of maternal obesity and early life exposure to high-fat diet on offspring liver phenotype, hepatokine profile, and key components of hepatic metabolism. To this end, we employed a murine high-fat diet-induced perinatal obesity model, investigating the offspring in early life and late adulthood. After exposure to perinatal obesity, the offspring showed a significantly increased body weight in early life with no histological signs of steatosis, but a dysregulated hepatokine profile. Proteomic profiling, followed by molecular analyses, revealed a decreased lipogenesis and increased fatty acid oxidation, suggesting a protective mechanism against the development of steatosis. These changes were accompanied by increased markers of lipid peroxidation and DNA damage, indicating increased oxidative stress. Concomitantly, the antioxidative enzymes catalase and superoxide dismutase 2 were significantly reduced and oxidative phosphorylation was impaired, implying an altered oxidative stress response. While changes in oxidative stress level were only detected in early life, the lipid metabolism was altered across life span. This metabolic programming could determine the resilience and susceptibility to chronic liver disease later in life.

Antioxidants and the risk of metabolic dysfunction-associated steatotic liver disease: results of National Health and Nutrition Examination Survey and two-sample Mendelian randomization analyses

BACKGROUND

The link between antioxidants and metabolic dysfunction-associated steatotic liver disease (MASLD) is a topic of considerable discussion in the field of observational studies, with the exact causal connections still being unclear.

METHODS

In this investigation, a cohort consisting of 17 061 participants from the National Health and Nutrition Examination Surveys was studied. Initially, a cross-sectional analysis was carried out to examine the relationship between the CDAI and MASLD. Further, Mendelian randomization (MR) was utilized to assess the possible causal links between antioxidant levels in the bloodstream and MASLD.

RESULTS

The association between the CDAI and MASLD was found to be significant in the fully adjusted logistic regression model, showing an OR of 0.95 [95% confidence interval (CI): 0.94-0.97; P  < 0.001]. The use of restricted cubic spline regression revealed no significant nonlinear association between the CDAI and the occurrence of MASLD ( Pnonlinearity  = 0.321). Additionally, MR findings did not suggest any causal connections between circulating levels of various antioxidants and MASLD. These antioxidants included vitamin A (retinol) (IVW: OR: 0.67, 95% CI: 0.33-1.36, P  = 0.272), vitamin C (ascorbate) (IVW: OR: 0.61, 95% CI: 0.34-1.09, P  = 0.094), vitamin E (α-tocopherol) (IVW: OR: 0.55, 95% CI: 0.13-2.25, P  = 0.407), vitamin E (γ-tocopherol) (IVW: OR: 0.89, 95% CI: 0.36-2.23, P  = 0.806), zinc (IVW: OR: 0.95, 95% CI: 0.82-1.09, P  = 0.449), selenium (IVW: OR: 0.98, 95% CI: 0.84-1.16, P  = 0.855), and carotene (IVW: OR: 0.80, 95% CI: 0.36-1.81, P  = 0.596).

CONCLUSION

The findings highlight a significant negative linear relationship between CDAI and MASLD prevalence in the observational component of the study. However, the MR analysis did not indicate any causal effects of circulating antioxidant levels on MASLD.

Exploring the molecular mechanisms of tirzepatide in alleviating metabolic dysfunction-associated fatty liver in mice through integration of metabolomics, lipidomics, and proteomics

Clinical studies have suggested that tirzepatide may also possess hepatoprotective effects; however, the molecular mechanisms underlying this association remain unclear. In our study, we performed biochemical analyses of serum and histopathological examinations of liver tissue in mice. To preliminarily explore the molecular mechanisms of tirzepatide on metabolic dysfunction-associated fatty liver disease (MAFLD), liquid chromatography-mass spectrometry (LC-MS) was employed for comprehensive metabolomic, lipidomic, and proteomic analyses in MAFLD mice fed a high-fat diet (HFD). The results demonstrated that tirzepatide significantly reduced serum levels of alanine transaminase (ALT) and aspartate transaminase (AST), as well as hepatic triglycerides (TG) and total cholesterol (TC), indicating its efficacy in treating MAFLD. Further findings revealed that tirzepatide reduced fatty acid uptake by downregulating Cd36 and Fabp2/4, as well as enhance the mitochondrial-lysosomal function by upregulating Lamp1/2. In addition, tirzepatide promoted cholesterol efflux and reduced cholesterol reabsorption by upregulating the expression of Hnf4a, Abcg5, and Abcg8. These results suggest that tirzepatide exerts its therapeutic effects on MAFLD by reducing fatty acid uptake, promoting cholesterol excretion, and enhancing mitochondrial-lysosomal function, providing a theoretical basis for a comprehensive understanding of tirzepatide.

Application and research progress of magnetic resonance proton density fat fraction in metabolic dysfunction-associated steatotic liver disease: a comprehensive review

Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD), formerly known as Non-Alcoholic Fatty Liver Disease (NAFLD), is a chronic liver disorder associated with disturbances in lipid metabolism. The disease is prevalent worldwide, particularly closely linked with metabolic syndromes such as obesity and diabetes. Magnetic Resonance Proton Density Fat Fraction (MRI-PDFF), serving as a non-invasive and highly quantitative imaging assessment tool, holds promising applications in the diagnosis and research of MASLD. This paper aims to comprehensively review and summarize the applications and research progress of MRI-PDFF technology in MASLD, analyze its strengths and challenges, and anticipate its future developments in clinical practice.

Augmenter of Liver Regeneration Crotonylation Assists in Mitochondria-ER Contact to Alleviate Hepatic Steatosis

BACKGROUND & AIMS

Crotonylation (Kcr), a newly identified post-translation modification (PTM), has been confirmed to be involved in diverse biological processes and human diseases as well. Metabolic dysfunction-associated steatotic liver disease (MASLD) poses a serious threat to people's health. Augmenter of liver regeneration (ALR) is an important liver regulatory protein, and the insufficiency of ALR expression is reported to accelerate liver steatosis progression to liver fibrosis or even hepatic carcinoma (HCC). However, the connection between dysregulated ALR crotonylation and MASLD pathogenesis remains largely unknown.

METHODS

Steatotic liver samples from human and Western diet (WD)-fed mice were employed for detecting Kcr levels. Mitochondrial function and mitochondria-ER interaction (MAM) relevant to ALR-Kcr modification was evaluated for hepatocyte lipid metabolism both in in vivo and in vitro experiments.

RESULTS

Global protein crotonylation (Kcr) as well as ALR-Kcr was significantly decreased in liver samples of patients with MASLD and WD mice. Histone deacetylase1/2 (HDAC1/2) and lysine acetyltransferase 8 (KAT8) were identified responsible for regulation of ALR-Kcr, which takes place at lysine 78 (K78). The decrease of ALR crotonylation might be related to the imbalance between HDAC1/2 and KAT8 expression, inhibited its interaction with MFN2, expanding MAM distance and impairing mitochondrial lipid metabolism, and consequently deteriorating hepatic steatosis.

CONCLUSIONS

The insufficient ALR crotonylation might be a crucial mechanism contributing to the pathogenesis of MASLD. Keeping ALR crotonylation level would be beneficial for the prevention and treatment of MASLD.

Betaine alleviates nonalcoholic fatty liver disease (NAFLD) via a manner involving BHMT/FTO/m6A/ PGC1α signaling

Nonalcoholic fatty liver disease (NAFLD) has emerged as a major public health crisis with significant health threats and economic burdens worldwide in the past decades. Betaine, a naturally occurring alkaloid compound present in various dietary sources including spinach and beets, has been shown to ameliorate hepatic lipid metabolism and attenuate (NAFLD), while the underlying mechanism remains elusive. Here, we propose a novel mechanism through which betaine exerts its protective effects against hepatic lipid accumulation and (NAFLD) from an epigenetics perspective. Specifically, we discover that betaine upregulates betaine homocysteine S-methyltransferase (BHMT) expression, leading to increased nicotinamide adenine dinucleotide phosphate (NADPH) production and subsequent upregulation of fat mass and obesity-associated protein (FTO) expression. Increased abundance of FTO targets peroxisome proliferator-activated receptor-gamma coactivator 1-alpha (PGC1α) mRNA and reduces the N6-methyladenosine (m6A) level in the CDS of Ppargc1α transcript, which positively regulates PGC1α expression and subsequently inhibits hepatic lipid accumulation. Overall, our works demonstrate that betaine may be a promising therapeutic strategy for treating (NAFLD) and improving liver function through the regulation of (NADPH) and m6A-mediated pathways.

The Role of the Gut Microbiome in the Development and Progression of Type 2 Diabetes and Liver Disease

Type 2 diabetes mellitus (T2DM) and progressive liver disease are 2 of the most significant global health concerns, and they have alarming and ever-increasing prevalence. A growing body of literature has demonstrated a potential multilateral link between gut microbiome dysbiosis and the development and progression of the above-mentioned conditions. Modulation of gut microbial composition from the norm is due to changes in diet allied with external factors such as age, genetics, and environmental changes. In this comprehensive review, we recapitulate the research to date investigating the links between gut microbiome dysbiosis and T2DM or liver disease, with special attention to the importance of diet. Additionally, we review the most commonly used tools and methodologies of investigating changes in the gut microbiome, highlighting the advantages and limitations of each strategy, before introducing a novel in vitro approach to the problem. Finally, the review offers recommendations for future research in this field that will allow better understanding of how the gut microbiota affects disease progression and of the prospects for intestinal microbiota-based therapeutic options.

Imeglimin Halts Liver Damage by Improving Mitochondrial Dysfunction in a Nondiabetic Male Mouse Model of Metabolic Dysfunction-Associated Steatohepatitis

Imeglimin promotes glucose-stimulated insulin secretion in the pancreas in a glucose-dependent manner and inhibits gluconeogenesis in the liver. Meanwhile, imeglimin can improve mitochondrial function in hepatocytes. We used a nondiabetic metabolic dysfunction-associated steatohepatitis (MASH) model to examine the effects of imeglimin on MASH independent of its glucose-lowering action. Mice fed a choline-deficient high-fat diet (CDA-HFD) were orally administered imeglimin (100 and 200 mg/kg twice daily), and MASH pathophysiology was evaluated after 8 weeks. Moreover, an in vitro study investigated the effects of imeglimin on palmitic acid (PA)-stimulated lipid accumulation, apoptosis, and mitochondrial dysfunction in human hepatocytes. CDA-HFD-fed mice showed hepatic steatosis, inflammation, and fibrosis without hyperglycemia. Imeglimin reduced hepatic steatosis in response to increased expression of β-oxidation-related markers. Imeglimin reduced reactive oxygen species accumulation and increased mitochondrial biogenesis in CDA-HFD-fed mice. Consequently, imeglimin suppressed hepatocyte apoptosis and decreased macrophage infiltration with reduced proinflammatory cytokine expression, suppressing hepatic fibrosis development. PA-stimulated hepatocytes induced lipogenesis, inflammatory cytokine production, and apoptosis, which were significantly suppressed by imeglimin. In mitochondrial function, imeglimin improved PA-stimulated decrease in mitochondrial membrane potential, mitochondrial complexes activity, oxygen consumption rate, and mitochondrial biogenesis marker expression. In conclusion, imeglimin could contribute to prevention of MASH progression through suppressing de novo lipogenesis and enhancing fatty acid oxidation.

Application and mechanism of Chinese herb medicine in the treatment of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a chronic liver condition closely associated with metabolic syndrome, with its incidence rate continuously rising globally. Recent studies have shown that the development of NAFLD is associated with insulin resistance, lipid metabolism disorder, oxidative stress and endoplasmic reticulum stress. Therapeutic strategies for NAFLD include lifestyle modifications, pharmacological treatments, and emerging biological therapies; however, there is currently no specific drug to treat NAFLD. However Chinese herb medicine (CHM) has shown potential in the treatment of NAFLD due to its unique therapeutic concepts and methods for centuries in China. This review aims to summarize the pathogenesis of NAFLD and some CHMs that have been shown to have therapeutic effects on NAFLD, thus enriching the scientific connotation of TCM theories and facilitating the exploration of TCM in the treatment of NAFLD.

Glucagon promotes increased hepatic mitochondrial oxidation and pyruvate carboxylase flux in humans with fatty liver disease

We assessed in vivo rates of hepatic mitochondrial oxidation, gluconeogenesis, and β-hydroxybutyrate (β-OHB) turnover by positional isotopomer NMR tracer analysis (PINTA) in individuals with metabolic-dysfunction-associated steatotic liver (MASL) (fatty liver) and MASL disease (MASLD) (steatohepatitis) compared with BMI-matched control participants with no hepatic steatosis. Hepatic fat content was quantified by localized 1H magnetic resonance spectroscopy (MRS). We found that in vivo rates of hepatic mitochondrial oxidation were unaltered in the MASL and MASLD groups compared with the control group. A physiological increase in plasma glucagon concentrations increased in vivo rates of hepatic mitochondrial oxidation by 50%-75% in individuals with and without MASL and increased rates of glucose production by ∼50% in the MASL group, which could be attributed in part to an ∼30% increase in rates of mitochondrial pyruvate carboxylase flux. These results demonstrate that (1) rates of hepatic mitochondrial oxidation are not substantially altered in individuals with MASL and MASLD and (2) glucagon increases rates of hepatic mitochondrial oxidation.

Telomerase reverse transcriptase protects against diabetic kidney disease by promoting AMPK/PGC-1a-regulated mitochondrial energy homeostasis

Disordered glucose and lipid metabolism, coupled with disturbed mitochondrial bioenergetics, are pivotal in the initiation and development of diabetic kidney disease (DKD). While the essential role of telomerase reverse transcriptase (TERT) in regulating mitochondrial function in the cardiovascular system has been recognized, its specific function in maintaining mitochondrial homeostasis in DKD remains unclear. This study aimed to explore how TERT regulates mitochondrial function and the underlying mechanisms. In vitro, human renal proximal tubular HK-2 cells exposed to high glucose/high fat (HG/HF) presented significant downregulation of TERT and AMPK dephosphorylation. This led to decreased ATP production, altered NAD+/NADH ratios, reduced mitochondrial complex activities, increased mitochondrial dysfunction, lipid accumulation, and reactive oxygen species (ROS) production. Knockdown of TERT (si-TERT) further exacerbated mitochondrial dysfunction, decreased mitochondrial membrane potential, and lowered levels of cellular oxidative phosphorylation and glycolysis, as determined via a Seahorse X24 flux analyzer. Conversely, mitochondrial dysfunction was significantly alleviated after pcDNA-TERT plasmid transfection and adeno-associated virus (AAV) 9-TERT gene therapy in vivo. Notably, treatment with an AMPK inhibitor, activator, and si-PGC-1a (peroxisome proliferator-activated receptor γ coactivator-1α), resulted in mitochondrial dysfunction and decreased expression of genes related to energy metabolism and mitochondrial biogenesis. Our findings reveal that TERT protects mitochondrial function and homeostasis by partially activating the AMPK/PGC-1a signaling pathway. These results establish a crucial foundation for understanding TERT's critical role inmitochondrial regulation and its protective effect on DKD.

Tao-Hong-Si-Wu-Tang improves thioacetamide-induced liver fibrosis by reversing ACSL4-mediated lipid accumulation and promoting mitophagy

ETHNOPHARMACOLOGICAL RELEVANCE

Liver fibrosis is a generic fibrous scarring event resulting from accumulation of extracellular matrix (ECM) proteins, easily progressing to end-stage liver diseases. Tao-Hong-Si-Wu-Tang (THSWT) is a traditional Chinese medicine formula applied in clinics to treat gynecological and chronic liver diseases. However, the role of THSWT on thioacetamide (TAA)-induced hepatic fibrosis and the specific mechanisms remains unclear.

AIM OF THE STUDY

To investigate the improving effects of THSWT on TAA-insulted hepatic fibrosis and the underlying mechanisms.

MATERIALS AND METHODS

UHPLC-MS/MS was performed to explore the chemical characterization of THSWT. Mice were orally administered with THSWT once daily for 6 weeks along with TAA challenge. Liver function was reflected through serum biomarkers and histopathological staining. RNA sequencing, non-targeted metabolomics and molecular biology experiments were applied to investigate the underlying mechanisms.

RESULTS

THSWT profoundly repaired lipid metabolism dysfunction and blocked collagen accumulation both in TAA-stimulated mice and in hepatocytes. Results of RNA sequencing and non-targeted metabolomics revealed that the anti-fibrotic effects of THSWT mostly relied on lipid metabolism repairment by increasing levels of acetyl-CoA, phosphatidylcholine, phosphatidylethanolamine, lysophosphatidylcholine and lysophosphatidylethanolamine, and decreasing relative abundances of acyl-CoA, total cholesterol, diacylglycerol, triacylglycerol and phosphatidylinositol. Mechanically, long-chain acyl-CoA synthetases 4 (ACSL4) was a key profibrotic target both in human and mice by disrupting lipid oxidation and metabolism in hepatic mitochondria. THSWT effectively blocked ACSL4 and promoted mitophagy to reverse above outcomes, which was verified by mitophagy depletion.

CONCLUSION

THSWT may be a promising therapeutic option for treating hepatic fibrosis and its complications by modulating lipid metabolism and promoting mitophagy in livers.

Saccharomyces boulardii Mitigates Fructose-Induced Non-Alcoholic Fatty Liver in Rats

Background and Objectives: Non-alcoholic fatty liver disease (NAFLD) is a growing global health concern closely linked to metabolic disorders, including obesity, insulin resistance, and dyslipidemia. Emerging evidence suggests that the gut-liver axis plays a critical role in the pathogenesis of NAFLD, with recent research highlighting the influence of gut microbiota, including fungal species such as Saccharomyces boulardii (S. boulardii). This study aimed to evaluate the effects of S. boulardii on lipid metabolism and oxidative stress in a rat model of fructose-induced NAFLD. Materials and Methods: Thirty Wistar rats were divided into three groups: a control group, a fatty liver group induced by 35% fructose supplementation, and a treatment group receiving S. boulardii (100 mg/kg/day) after fructose induction. Results: Biochemical analyses revealed that the treatment group exhibited significantly lower plasma levels of malondialdehyde (MDA), alanine aminotransferase (ALT), total triglycerides, and cholesterol compared to the untreated fatty liver group (p < 0.05). Furthermore, liver tissue analysis showed a marked reduction in lipid accumulation and fatty infiltration in the treatment group, with no visible lipid vacuoles in hepatocytes. The expression of aquaporin-8 (AQP8) and sirtuin-1 (SIRT1), key markers associated with hepatocyte function and lipid metabolism, was significantly higher in the S. boulardii group compared to the fatty liver group (p < 0.001). Conclusions: These findings indicate that S. boulardii supplementation mitigates the metabolic and oxidative stress-related alterations associated with fructose-induced NAFLD. In conclusion, our study suggests that S. boulardii exerts protective effects on the liver by reducing lipid accumulation and oxidative stress, highlighting its potential as a therapeutic intervention for NAFLD.

Setting the curve: the biophysical properties of lipids in mitochondrial form and function

Mitochondrial membranes are defined by their diverse functions, complex geometries, and unique lipidomes. In the inner mitochondrial membrane, highly curved membrane folds known as cristae house the electron transport chain and are the primary sites of cellular energy production. The outer mitochondrial membrane is flat by contrast, but is critical for the initiation and mediation of processes key to mitochondrial physiology: mitophagy, interorganelle contacts, fission and fusion dynamics, and metabolite transport. While the lipid composition of both the inner mitochondrial membrane and outer mitochondrial membrane have been characterized across a variety of cell types, a mechanistic understanding for how individual lipid classes contribute to mitochondrial structure and function remains nebulous. In this review, we address the biophysical properties of mitochondrial lipids and their related functional roles. We highlight the intrinsic curvature of the bulk mitochondrial phospholipid pool, with an emphasis on the nuances surrounding the mitochondrially-synthesized cardiolipin. We also outline emerging questions about other lipid classes - ether lipids, and sterols - with potential roles in mitochondrial physiology. We propose that further investigation is warranted to elucidate the specific properties of these lipids and their influence on mitochondrial architecture and function.

The Interplay between Liver and Adipose Tissue in the Onset of Liver Diseases: Exploring the Role of Vitamin Deficiency

The deficiency of vitamins, a condition known as "hidden hunger", causes comprehensive pathological states. Research over the years has identified a relationship between liver diseases and hypovitaminosis or defects in vitamin metabolism. The exact mechanisms remain elusive; however, the crucial involvement of specific vitamins in metabolic functions, alongside the reclassification of liver disease as metabolic dysfunction-associated steatotic liver disease (MASLD), has prompted researchers to investigate the potential cause-effect dynamics between vitamin deficiency and liver disease. Moreover, scientists are increasingly investigating how the deficiency of vitamins might disrupt specific organ crosstalk, potentially contributing to liver disease. Although the concept of a dysmetabolic circuit linking adipose tissue and the liver, leading to liver disease, has been discussed, the possible involvement of vitamin deficiency in this axis is a relatively recent area of study, with numerous critical aspects yet to be fully understood. In this review, we examine research from 2019 to July 2024 focusing on the possible link between liver-adipose tissue crosstalk and vitamin deficiency involved in the onset and progression of non-alcoholic fatty liver disease (NAFLD). Studies report that vitamin deficiency can affect the liver-adipose tissue axis, mainly affecting the regulation of systemic energy balance and inflammation.

tBHQ mitigates fatty liver ischemia-reperfusion injury by activating Nrf2 to attenuate hepatocyte mitochondrial damage and macrophage STING activation

BACKGROUND

Liver ischemia-reperfusion (IR) injury is an inevitable pathophysiological process in various liver surgeries. Previous studies have found that IR injury is exacerbated in fatty liver due to significant hepatocellular damage and macrophage inflammatory activation, though the underlying mechanisms are not fully understood. In this study, we aim to explore the role and mechanism of Nrf2 (Nuclear factor erythroid 2-related factor 2) signaling in regulating hepatocellular damage and macrophage immune response in fatty liver IR injury.

METHODS

The study used high-fat diet-induced fatty liver mice to establish an IR model, alongside an in vitro co-culture system of primary hepatocytes and macrophages. This approach was used to examine mitochondrial dysfunction, oxidative stress, mitochondrial DNA (mtDNA) release, and activation of macrophage STING (Stimulator of interferon genes) signaling. We also conducted recovery verification using H-151 (a STING inhibitor) and tBHQ (an Nrf2 activator).

RESULTS

Compared to the control group, mice on a high-fat diet demonstrated more severe liver IR injury, as evidenced by increased histological damage, elevated liver enzyme levels, and heightened inflammatory markers. The HFD group showed significant oxidative stress and mitochondrial dysfunction and damage post-IR, as indicated by elevated levels of ROS and lipid peroxidation markers, and decreased antioxidant enzyme activity. Elevated mtDNA release from hepatocytes post-IR activated macrophage STING signaling, worsening inflammation and liver damage. However, STING signaling inhibition with H-151 in vivo or employing STING knockout macrophages significantly reduced these injuries. In-depth mechanism studies have found that the transfer of Nrf2 protein into the nucleus of liver cells after IR in fatty liver is reduced. Pre-treatment with tBHQ ameliorated liver oxidative stress, mitochondrial damage and suppressed the macrophage STING signaling activation.

CONCLUSIONS

Our study reveals a novel mechanism where the interaction between hepatocellular damage and macrophage inflammation intensifies liver IR injury in fatty liver. Enhancing Nrf2 activation to protect mitochondrial from oxidative stress damage and inhibiting macrophage STING signaling activation emerge as promising strategies for clinical intervention in fatty liver IR injury.

Mettl3-m6A-YTHDF1 axis promotion of mitochondrial dysfunction in metabolic dysfunction-associated steatotic liver disease

BACKGROUND

N6-methyladenosine (m6A) mRNA modification and mitochondrial function hold paramount importance in the advancement of metabolic dysfunction-associated steatotic liver disease (MASLD).

AIM

The aim of this study was to elucidate the impact of m6A on hepatic mitochondrial dysfunction and provide a novel perspective for a more comprehensive understanding of the pathogenesis of MASLD.

METHODS

High-throughput screening methods were used to identify the underlying transcriptome and proteome changes in MASLD model mice. Western blotting, blue native gel electrophoresis (BNGE), dot blot, and Seahorse analyses were conducted to identify and validate the underlying regulatory mechanisms of m6A on mitochondria.

RESULTS

In vivo, abnormal m6A modification in MASLD was attributed to the upregulation of methyltransferase like 3 (Mettl3) and the downregulation of YTH N6-methyladenosine RNA binding protein 1 (YTHDF1) induced by high-fat foods. In vitro, knockdown of Mettl3 inhibited hepatic oxidative phosphorylation (OXPHOS) and the mitochondrial respiratory chain (MRC), while overexpression of Mettl3 promoted these processes. However, knockout of the reader protein YTHDF1, which plays a crucial role in the m6A modification process, counteracted the effect of Mettl3 and suppressed mitochondrial OXPHOS.

CONCLUSIONS

In MASLD, damage to the MRC may be regulated by the Mettl3-m6A-YTHDF1 axis, particularly by the role of YTHDF1. Modulation of the Mettl3-m6A-YTHDF1 axis has the potential to improve mitochondrial function, alleviate MASLD symptoms, and decrease the likelihood of disease progression.

miR-33 deletion in hepatocytes attenuates MASLD-MASH-HCC progression

The complexity of the mechanisms underlying metabolic dysfunction-associated steatotic liver disease (MASLD) progression remains a significant challenge for the development of effective therapeutics. miRNAs have shown great promise as regulators of biological processes and as therapeutic targets for complex diseases. Here, we study the role of hepatic miR-33, an important regulator of lipid metabolism, during the progression of MASLD and the development of hepatocellular carcinoma (HCC). We report that miR-33 was elevated in the livers of humans and mice with MASLD and that its deletion in hepatocytes (miR-33 HKO) improved multiple aspects of the disease, including steatosis and inflammation, limiting the progression to metabolic dysfunction-associated steatotic hepatitis (MASH), fibrosis, and HCC. Mechanistically, hepatic miR-33 deletion reduced lipid synthesis and promoted mitochondrial fatty acid oxidation, reducing lipid burden. Additionally, absence of miR-33 altered the expression of several known miR-33 target genes involved in metabolism and resulted in improved mitochondrial function and reduced oxidative stress. The reduction in lipid accumulation and liver injury resulted in decreased YAP/TAZ pathway activation, which may be involved in the reduced HCC progression in HKO livers. Together, these results suggest suppressing hepatic miR-33 may be an effective therapeutic approach to temper the development of MASLD, MASH, and HCC in obesity.

The newly proposed plasma-glycosylated hemoglobin A1c/High-Density lipoprotein cholesterol ratio serves as a simple and practical indicator for screening metabolic associated fatty liver disease: an observational study based on a physical examination population

BACKGROUND

Glycotoxicity and lipotoxicity are key pathophysiological mechanisms underlying the development of metabolic associated fatty liver disease (MAFLD). The primary objective of this study is to investigate the association between the newly proposed Plasma-Glycosylated Hemoglobin A1c/High-Density Lipoprotein Cholesterol Ratio (HbA1c/HDL-C ratio) and the risk of MAFLD.

METHODS

A study population of 14,251 individuals undergoing health examinations was included. The association between the HbA1c/HDL-C ratio and MAFLD was analyzed using multivariable logistic regression and restricted cubic spline (RCS) analysis. Exploratory analyses were conducted to assess variations in this association across subgroups stratified by gender, age, body mass index (BMI), exercise habits, drinking status, and smoking status. The discriminatory value of the HbA1c/HDL-C ratio and its components for screening MAFLD was evaluated using receiver operating characteristic (ROC) curves.

RESULTS

A total of 1,982 (13.91%) subjects were diagnosed with MAFLD. After adjusting for confounding factors, we found a significant positive association between the HbA1c/HDL-C ratio and MAFLD [odds ratio (OR) 1.34, 95% confidence interval (CI): 1.25, 1.44]. No significant differences in this association were observed across all subgroups (All P for interaction > 0.05). Furthermore, through RCS analysis, we observed a nonlinear positive correlation between the HbA1c/HDL-C ratio and MAFLD (P for non-linearity < 0.001), with a potential threshold effect point (approximately 3 for the HbA1c/HDL-C ratio). Beyond this threshold point, the slope of the MAFLD prevalence curve increased rapidly. Additionally, in further ROC analysis, we found that for the identification of MAFLD, the HbA1c/HDL-C ratio was significantly superior to HbA1c and HDL-C, with an area under the curve (AUC) and optimal threshold of 0.81 and 4.08, respectively.

CONCLUSIONS

Our findings suggest that the newly proposed HbA1c/HDL-C ratio serves as a simple and practical indicator for assessing MAFLD, exhibiting well-discriminatory performance in screening for MAFLD.

Diosgenin attenuates nonalcoholic hepatic steatosis through the hepatic SIRT1/PGC-1α pathway

The prevalence of nonalcoholic fatty liver disease (NAFLD) has been increasing worldwide in recent years, causing severe economic and social burdens. Therefore, the lack of currently approved drugs for anti-NAFLD has gradually gained attention. SIRT1, as a member of the sirtuins family, is now the most widely studied in the pathophysiology of many metabolic diseases, and has great potential for preventing and treating NAFLD. Natural products such as Diosgenin (DG) have the potential to be developed as clinical drugs for the treatment of NAFLD due to their excellent multi-target therapeutic effects. In this study, we found that DG can activate the SIRT1/PGC-1α pathway and upregulate the expression of its downstream targets nuclear respiratory factor 1 (NRF1), complex IV (COX IV), mitofusin-2 (MFN2), and PPARα (perox-isome proliferator-activated receptor α) in SD rats induced by high-fat diet (HFD) and HepG2 cells caused by free fatty acids (FFAs, sodium oleate: sodium palmitate = 2:1). Conversely, the levels of dynamin-related protein 1 (DRP1) and inflammatory factors, including NF-κB p65, IL6, and TNFα, were downregulated both in vitro and in vivo. This improved mitochondrial dysfunction, fatty acid oxidation (FAO), lipid accumulation, steatosis, oxidative stress, and hepatocyte inflammation. Subsequently, we applied SIRT1 inhibitor EX527 and SIRT1 agonist SRT1720 to confirm further the necessity of activating SIRT1 for DG to exert therapeutic effects on NAFLD. In summary, these results further demonstrate the potential therapeutic role of DG as a SIRT1 natural agonist for NAFLD. (Graphical Abstracts).

Hepatic Steatosis Can Be Partly Generated by the Gut Microbiota-Mitochondria Axis via 2-Oleoyl Glycerol and Reversed by a Combination of Soy Protein, Chia Oil, Curcumin and Nopal

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a serious health problem, and recent evidence indicates that gut microbiota plays a key role in its development. It is known that 2-oleoyl glycerol (2-OG) produced by the gut microbiota is associated with hepatic fibrosis, but it is not known whether this metabolite is involved in the development of hepatic steatosis. The aim of this study was to evaluate how a high-fat-sucrose diet (HFS) increases 2-OG production through gut microbiota dysbiosis and to identify whether this metabolite modifies hepatic lipogenesis and mitochondrial activity for the development of hepatic steatosis as well as whether a combination of functional foods can reverse this process. Wistar rats were fed the HFS diet for 7 months. At the end of the study, body composition, biochemical parameters, gut microbiota, protein abundance, lipogenic and antioxidant enzymes, hepatic 2-OG measurement, and mitochondrial function of the rats were evaluated. Also, the effect of the consumption of functional food with an HFS diet was assessed. In humans with MASLD, we analyzed gut microbiota and serum 2-OG. Consumption of the HFS diet in Wistar rats caused oxidative stress, hepatic steatosis, and gut microbiota dysbiosis, decreasing α-diversity and increased Blautia producta abundance, which increased 2-OG. This metabolite increased de novo lipogenesis through ChREBP and SREBP-1. 2-OG significantly increased mitochondrial dysfunction. The addition of functional foods to the diet modified the gut microbiota, reducing Blautia producta and 2-OG levels, leading to a decrease in body weight gain, body fat mass, serum glucose, insulin, cholesterol, triglycerides, fatty liver formation, and increased mitochondrial function. To use 2-OG as a biomarker, this metabolite was measured in healthy subjects or with MASLD, and it was observed that subjects with hepatic steatosis II and III had significantly higher 2-OG than healthy subjects, suggesting that the abundance of this circulating metabolite could be a predictor marker of hepatic steatosis.

Shenling Baizhu powder alleviates non-alcoholic fatty liver disease by modulating autophagy and energy metabolism in high-fat diet-induced rats

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) has emerged as a burgeoning health problem worldwide, but no specific drug has been approved for its treatment. Shenling Baizhu powder (SL) is extensively used to treat NAFLD in Chinese clinical practice. However, the therapeutic components and pharmacological mechanisms of SL against NAFLD have not been thoroughly investigated.

PURPOSE

This study aimed to investigate the pharmacological impact and molecular mechanism of SL on NAFLD.

METHODS

First, we established an animal model of NAFLD by high-fat diet (HFD) feeding, and evaluated the therapeutic efficacy of SL on NAFLD by physiological, biochemical, pathological, and body composition analysis. Next, the effect of SL on autophagic flow in NAFLD rats was evaluated by ultrastructure, immunofluorescence staining, and western blotting. Moreover, an integrated strategy of targeted energy metabolomics and network pharmacology was performed to characterize autophagy-related genes and explore the synergistic effects of SL active compounds. UPLC-MS/MS, molecular docking combined with in vivo and in vitro experiments were conducted to verify the key compounds and genes. Finally, a network was established among SL-herb-compound-genes-energy metabolites-NAFLD, which explains the complicated regulating mechanism of SL on NAFLD.

RESULTS

We discovered that SL decreased hepatic lipid accumulation, hepatic steatosis, and insulin resistance, and improved systemic metabolic disorders and pathological abnormalities. Subsequently, an integrated strategy of targeted energy metabolomics and network pharmacology identified quercetin, ellagic acid, kaempferol, formononetin, stigmasterol, isorhamnetin and luteolin as key compounds; catalase (CAT), AKT serine/threonine kinase 1 (AKT), nitric oxide synthase 3 (eNOS), NAD(P)H quinone dehydrogenase 1 (NQO1), heme oxygenase 1 (HO-1) and hypoxia-inducible factor 1 subunit alpha (HIF-1α) were identified as key genes; while nicotinamide adenine dinucleotide phosphate (NADP) and succinate emerged as key energy metabolites. Mechanistically, we revealed that SL may exert its anti-NAFLD effect by inducing autophagy activation and forming a comprehensive regulatory network involving key compounds, key genes, and key energy metabolites, ultimately alleviating oxidative stress, endoplasmic reticulum stress, and mitochondrial dysfunction.

CONCLUSION

Our study demonstrated the therapeutic effect of SL in NAFLD models, and establishes a basis for the development of potential products from SL plant materials for the treatment of NAFLD.

Post-Liver Transplant Metabolic Syndrome

Non-alcoholic steatohepatitis (NASH) is the second most frequent cause of liver transplantation following alcoholic liver disease. With longer follow-up and increased survival rates, the occurrence rate of the metabolic syndrome is increasing with time among liver transplant recipients. Reappearances of non-alcoholic fatty liver disease after transplantation, both as recurring cases and new instances, are prevalent; nonetheless, the recurrence of fibrosis is minimal. Recognizing populations at elevated risk and enhancing the management of metabolic-related conditions are crucial for maintaining a healthy transplanted organ, particularly considering the prolonged utilization of immunosuppressive treatments. Furthermore, NASH-related cirrhosis patients who had transplant are at a greater risk of cardiovascular, renal events and increased incidence of cancer, necessitating a unique care strategy. This review discusses post-transplant metabolic syndrome, risk factors, pathogenesis, diagnosis, prevention strategy, recurrent and de novo NAFLD and customized immunosuppression.

Suppression of hepatic ChREBP⍺-CYP2C50 axis-driven fatty acid oxidation sensitizes mice to diet-induced MASLD/MASH

OBJECTIVES

Compromised hepatic fatty acid oxidation (FAO) has been observed in human MASH patients and animal models of MASLD/MASH. It remains poorly understood how and when the hepatic FAO pathway is suppressed during the progression of MASLD towards MASH. Hepatic ChREBP⍺ is a classical lipogenic transcription factor that responds to the intake of dietary sugars.

METHODS

We examined its role in regulating hepatocyte fatty acid oxidation (FAO) and the impact of hepatic Chrebpa deficiency on sensitivity to diet-induced MASLD/MASH in mice.

RESULTS

We discovered that hepatocyte ChREBP⍺ is both necessary and sufficient to maintain FAO in a cell-autonomous manner independently of its DNA-binding activity. Supplementation of synthetic PPAR⍺/δ agonist is sufficient to restore FAO in Chrebp-/- primary mouse hepatocytes. Hepatic ChREBP⍺ was decreased in mouse models of diet-induced MAFSLD/MASH and in patients with MASH. Hepatocyte-specific Chrebp⍺ knockout impaired FAO, aggravated liver steatosis and inflammation, leading to early-onset fibrosis in response to diet-induced MASH. Conversely, liver overexpression of ChREBP⍺-WT or its non-lipogenic mutant enhanced FAO, reduced lipid deposition, and alleviated liver injury, inflammation, and fibrosis. RNA-seq analysis identified the CYP450 epoxygenase (CYP2C50) pathway of arachidonic acid metabolism as a novel target of ChREBP⍺. Over-expression of CYP2C50 partially restores hepatic FAO in primary hepatocytes with Chrebp⍺ deficiency and attenuates preexisting MASH in the livers of hepatocyte-specific Chrebp⍺-deleted mice.

CONCLUSIONS

Our findings support the protective role of hepatocyte ChREBPa against diet-induced MASLD/MASH in mouse models in part via promoting CYP2C50-driven FAO.

RNF31 alleviates liver steatosis by promoting p53/BNIP3-related mitophagy in hepatocytes

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) is one of the liver illnesses that may be affected by mitophagy, which is the selective removal of damaged mitochondria. RNF31, an E3 ubiquitin ligase, is carcinogenic in many malignancies. However, the influence of RNF31 on mitochondrial homeostasis and NAFLD development remains unknown.

METHODS

Oleic-palmitic acid treated hepatocytes and high-fat diet (HFD)-fed mice were established to observe the effect of RNF31 on hepatocyte mitophagy and steatosis. Mitophagy processes were comprehensively assessed by mt-Keima fluorescence imaging, while global changes in hepatic gene expression were measured by RNA-seq.

RESULTS

The present study discovered a reduction in RNF31 expression in lipotoxic hepatocytes with mitochondrial dysfunction. The observed decrease in RNF31 expression was associated with reduced mitochondrial membrane potential, disturbed mitophagy, and increased steatosis. Additionally, the findings indicated that RNF31 is a pivotal factor in the initiation of mitophagy and the facilitation of mitochondrial homeostasis, resulting in a decrease in steatosis in lipotoxic hepatocytes. Mechanistically, RNF31 enhanced p53 ubiquitination and subsequent proteasomal degradation. Down-regulation of p53 led to increased expression of the mitophagy receptor protein BCL2 and adenovirus E1B 19 kDa-interacting protein 3 (BNIP3), thereby promoting mitophagy in hepatocytes. Furthermore, it was demonstrated that the transportation of RNF31 via small extracellular vesicles derived from mesenchymal stem cells (referred to as sEV) had a substantial influence on reducing hepatic steatosis and restoring liver function in HFD-fed mice.

CONCLUSIONS

The findings highlight RNF31's essential role in the regulation of mitochondrial homeostasis in hepatocytes, emphasizing its potential as a therapeutic target for NAFLD.

Reactive Oxygen Species-Responsive Delivery of a Notch Inhibitor to Alleviate Nonalcoholic Steatohepatitis by Inhibiting Hepatic de Novo Lipogenesis and Inflammation

With the increased prevalence of nonalcoholic steatohepatitis (NASH) in the world, effective pharmacotherapy in clinical practice is still lacking. Previous studies have shown that dibenzazepine (DBZ), a Notch inhibitor, could alleviate NASH development in a mouse model. However, low bioavailability, poor water solubility, and extrahepatic side effects restrict its clinical application. To overcome these barriers, we developed a reactive oxygen species (ROS)-sensitive nanoparticle based on the conjugation of bilirubin to poly(ethylene glycol) (PEG) chains, taking into account the overaccumulation of hepatic ROS in the pathologic state of nonalcoholic steatohepatitis (NASH). The PEGylated bilirubin can self-assemble into nanoparticles in an aqueous solution and encapsulate insoluble DBZ into its hydrophobic cavity. DBZ nanoparticles (DBZ Nps) had good stability, rapidly released DBZ in response to H2O2, and effectively scavenged intracellular ROS of hepatocytes. After systemic administration, DBZ Nps could accumulate in the liver of the NASH mice, extend persistence in circulation, and improve the bioavailability of DBZ. Furthermore, DBZ Nps significantly improved glucose intolerance, relieved hepatic lipid accumulation and inflammation, and ameliorated NASH-induced liver fibrosis. Additionally, DBZ Nps had no significant extrahepatic side effects. Taken together, our results highlight the potential of the ROS-sensitive DBZ nanoparticle as a promising therapeutic strategy for NASH.

Deciphering the molecular pathways of saroglitazar: A dual PPAR α/γ agonist for managing metabolic NAFLD

Saroglitazar (SARO), a dual peroxisome proliferator activated receptor (PPAR)-α/γ agonist, has been used to treat metabolic diseases such as insulin resistance and diabetic dyslipidemia in patients with non-alcoholic fatty liver disease (NAFLD). SARO, administered at a dose of 4 mg/day, has been consistently studied in clinical trials with different time points ranging from 4 to 24 weeks with NAFLD patients. Due to its PPAR-γ agonistic action, SARO prevents adipose tissue-mediated fatty acid delivery to the liver by increasing insulin sensitivity and regulating adiponectin and leptin levels in adipose tissue. In hepatocytes, SARO induces fatty acid β-oxidation in mitochondria and transcriptionally activates lipid metabolizing genes in peroxisomes. SARO inhibits insulin resistance, thereby preventing the activation of sterol regulatory element-binding proteins -1c and carbohydrate response element binding protein in hepatocytes through its PPAR-α agonistic action. SARO treatment reduces lipotoxicity-mediated oxidative stress by activating the nuclear factor erythroid 2-related factor 2 and transcriptionally expressing the antioxidants from the antioxidant response element in the nucleus through its PPAR-γ agonistic action. SARO provides a PPAR-α/γ-mediated anti-inflammatory effect by preventing the phosphorylation of mitogen-activated protein kinases (JNK and ERK) and nuclear factor kappa B in hepatocytes. Additionally, SARO interferes with transforming growth factor-β/Smad downstream signaling, thereby reducing liver fibrosis progression through its PPAR-α/γ agonistic actions. Thus, SARO improves insulin resistance and dyslipidemia in NAFLD, reduces lipid accumulation in the liver, and thereby prevents mitochondrial toxicity, oxidative stress, inflammation, and fibrosis progression. This review summarizes the possible molecular mechanism of SARO in the NAFLD.

Hepatokine ITIH3 protects against hepatic steatosis by downregulating mitochondrial bioenergetics and de novo lipogenesis

Recent studies demonstrate that liver secretory proteins, also known as hepatokines, regulate normal development, obesity, and simple steatosis to non-alcoholic steatohepatitis (NASH) progression. Using a panel of ∼100 diverse inbred strains of mice and a cohort of bariatric surgery patients, we found that one such hepatokine, inter-trypsin inhibitor heavy chain 3 (ITIH3), was progressively lower in severe non-alcoholic fatty liver disease (NAFLD) disease states highlighting an inverse relationship between Itih3/ITIH3 expression and NAFLD severity. Follow-up animal and cell culture models demonstrated that hepatic ITIH3 overexpression lowered liver triglyceride and lipid droplet accumulation, respectively. Conversely, ITIH3 knockdown in mice increased the liver triglyceride in two independent NAFLD models. Mechanistically, ITIH3 reduced mitochondrial respiration and this, in turn, reduced liver triglycerides, via downregulated de novo lipogenesis. This was accompanied by increased STAT1 signaling and Stat3 expression, both of which are known to protect against NAFLD/NASH. Our findings indicate hepatokine ITIH3 as a potential biomarker and/or treatment for NAFLD.

Machine learning-based algorithm identifies key mitochondria-related genes in non-alcoholic steatohepatitis

BACKGROUND

Evidence suggests that hepatocyte mitochondrial dysfunction leads to abnormal lipid metabolism, redox imbalance, and programmed cell death, driving the onset and progression of non-alcoholic steatohepatitis (NASH). Identifying hub mitochondrial genes linked to NASH may unveil potential therapeutic targets.

METHODS

Mitochondrial hub genes implicated in NASH were identified via analysis using 134 algorithms.

RESULTS

The Random Forest algorithm (RF), the most effective among the 134 algorithms, identified three genes: Aldo-keto reductase family 1 member B10 (AKR1B10), thymidylate synthase (TYMS), and triggering receptor expressed in myeloid cell 2 (TREM2). They were upregulated and positively associated with genes promoting inflammation, genes involved in lipid synthesis, fibrosis, and nonalcoholic steatohepatitis activity scores in patients with NASH. Moreover, using these three genes, patients with NASH were accurately categorized into cluster 1, exhibiting heightened disease severity, and cluster 2, distinguished by milder disease activity.

CONCLUSION

These three genes are pivotal mitochondrial genes implicated in NASH progression.

Corn Oligopeptide Alleviates Nonalcoholic Fatty Liver Disease by Regulating the Sirtuin Signaling Pathway

Nonalcoholic fatty liver disease (NAFLD) represents the most prevalent type of chronic liver disease, spanning from simple steatosis to nonalcoholic steatohepatitis (NASH). Corn oligopeptide (CP) is a functional peptide known for its diverse pharmacological effects on metabolism. In this study, we evaluated the protective activity of CP against fatty liver disease. Oral administration of CP significantly reduced body weight gain by 2.95%, serum cholesterol by 22.54%, and liver injury, as evidenced by a reduction of 32.19% in serum aspartate aminotransferase (AST) and 49.10% in alanine aminotransferase (ALT) levels in mice subjected to a high-fat diet (HFD). In a streptozotocin/HFD-induced NASH mouse model, CP attenuated body weight gain by 5.11%, liver injury (with a 34.15% decrease in AST and 11.43% decrease in ALT), and, to some extent, liver inflammation and fibrosis. Proteomic analysis revealed the modulation of oxidative phosphorylation and sirtuin (SIRT) signaling pathways by CP. Remarkably, CP selectively inhibited the hepatic expression of mitochondrial SIRT3 and SIRT5 in both HFD and NASH models. In summary, CP demonstrates a preventive effect against metabolic-stress-induced NAFLD progression by modulating oxidative stress and the SIRT signaling pathway, suggesting the potential of CP as a therapeutic agent for the treatment of NAFLD and advanced-stage NASH.

Effect of Gracilaria vermiculophylla Macroalga on Non-Alcoholic Fatty Liver Disease in Obese Rats

Marine algae are valuable sources of bioactive compounds that have the potential to be used in the management of various pathologies. Despite the increasing prevalence of NAFLD, the absence of an approved effective pharmacological treatment with demonstrable effectiveness persists. In this context, the aim of the present study is to assess the effect of Gracilaria vermiculophylla red seaweed dietary supplementation on hepatic lipid accumulation, as well as on oxidative stress, inflammation and fibrosis- related markers on obese fa/fa Zucker rats fed with a standard diet, supplemented or not with 2.5% or 5% dehydrated Gracilaria vermiculophylla. After a six-week supplementation with the macroalga, no significant reduction in hepatic total lipid content or hepatic triglyceride content was observed. However, both doses were able to diminish hepatic NEFA concentration by reducing de novo lipogenesis and increasing mitochondrial biogenesis. Moreover, supplementation with the dose of 2.5% improved some oxidative stress and inflammation-related markers. Supplementation with the dose of 5% did not exert these clear beneficial effects. Thus, this study demonstrates that while Gracilaria vermiculophylla may not mitigate hepatic steatosis, it could exert protective effects on the liver by reducing NEFA content and enhancing oxidative stress and inflammation parameters.

Chronic exposure to 3,6-dichlorocarbazole exacerbates non-alcoholic fatty liver disease in zebrafish by disrupting lipid metabolism and inducing special lipid biomarker accumulation

Most previous studies have focused primarily on the adverse effects of environmental chemicals on organisms of good healthy. Although global prevalence of non-alcoholic fatty liver disease (NAFLD) has reached approximately 25%, the impact of environmentally persistent organic chemicals on organisms with NAFLD is substantially unknown. Polyhalogenated carbazoles (PHCZs) as emerging contaminants have been frequently detected in the environment and organisms. In this study, we investigated the impact of the most frequently detected PHCZs, 3,6-dichlorocarbazole (36-CCZ), on zebrafish with high-fat diet (HFD)-induced NAFLD. After 4 weeks exposure to environmentally relevant concentrations of 36-CCZ (0.16-0.45 μg/L), the accumulation of lipid in zebrafish liver dramatically increased, and the transcription of genes involved in lipid synthesis, transport and oxidation was significantly upregulated, demonstrating that 36-CCZ had exacerbated the NAFLD in zebrafish. Lipidomic analysis indicated that 36-CCZ had significantly affected liver lipid metabolic pathways, mainly including glycerolipids and glycerophospholipids. Additionally, fifteen lipids were identified as potential lipid biomarkers for 36-CCZ exacerbation of NAFLD, including diacylglycerols (DGs), triglycerides (TGs), phosphatidylcholines (PCs), phosphatidylethanolamines (PEs), phosphatidic acid (PA), and phosphatidylinositol (PI). These findings demonstrate that long-term exposure to 36-CCZ can promote the progression of NAFLD, which will contribute to raising awareness of the health risks of PHCZs.

Unveiling global research trends and hotspots on mitochondria in NAFLD from 2000 to 2023: A bibliometric analysis

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) has garnered significant attention in the past decade as a prevalent chronic liver condition. Despite a growing body of evidence implicating mitochondria in NAFLD development, comprehensive bibliometric analyses within this research domain are scarce. This study aims to provide a thorough overview of the knowledge framework and key research areas related to mitochondria in the context of NAFLD, utilizing bibliometric techniques.

METHODS

A comprehensive search of publications on mitochondria in NAFLD from 2000 to 2023 was conducted using the Web of Science Core Collection database. VOSviewers, CiteSpace, and the R package "bibliometrix" were employed for a precise assessment of the literature.

RESULTS

Examining 2530 articles from 77 countries, primarily led by the United States and China, revealed a consistent increase in publications on mitochondria's role in NAFLD. Leading research institutions include the University of Coimbra, the University of Missouri, the Chinese Academy of Sciences, Fudan University, and Shanghai Jiao Tong University. Notably, the International Journal of Molecular Sciences emerged as the most popular journal, and Hepatology was the most frequently cited. With contributions from 14,543 authors, Michael Roden published the highest number of papers, and A. J. Samyal was the most frequently cocited author. Key focus areas include investigating mitochondrial mechanisms impacting NAFLD and developing therapeutic strategies targeting mitochondria. Emerging research hotspots are associated with keywords such as "inflammation," "mitochondrial dysfunction," "autophagy," "obesity," and "insulin resistance."

CONCLUSION

This study, the first comprehensive bibliometric analysis, synthesizes research trends and advancements in the role of mitochondria in NAFLD. Insights derived from this analysis illuminate current frontiers and emerging areas of interest, providing a valuable reference for scholars dedicated to mitochondrial studies.

GBA3 promotes fatty acid oxidation and alleviates non-alcoholic fatty liver by increasing CPT2 transcription

BACKGROUND

Excessive lipids accumulation and hepatocytes death are prominent characteristics of non-alcoholic fatty liver disease (NAFLD). Nonetheless, the precise pathophysiological mechanisms are not fully elucidated.

METHODS

HepG2 cells stimulated with palmitic acids and rats fed with high-fat diet were used as models for NAFLD. The impact of Glucosylceramidase Beta 3 (GBA3) on fatty acid oxidation (FAO) was assessed using Seahorse metabolic analyzer. Lipid content was measured both in vitro and in vivo. To evaluate NAFLD progression, histological analysis was performed along with measurements of inflammatory factors and liver enzyme levels. Western blot and immunohistochemistry were employed to examine the activity levels of necroptosis. Flow cytometry and reactive oxygen species (ROS) staining were utilized to assess levels of oxidative stress.

RESULTS

GBA3 promoted FAO and enhanced the mitochondrial membrane potential without affecting glycolysis. These reduced the lipid accumulation. Rats supplemented with GBA3 exhibited lower levels of inflammatory factors and liver enzymes, resulting in a slower progression of NAFLD. GBA3 overexpression reduced ROS and the ratio of cell apoptosis. Phosphorylation level was reduced in the essential mediator, MLKL, implicated in necroptosis. Mechanistically, as a transcriptional coactivator, GBA3 promoted the expression of Carnitine Palmitoyltransferase 2 (CPT2), which resulted in enhanced FAO.

CONCLUSIONS

Increased FAO resulting from GBA3 reduced oxidative stress and the production of ROS, thereby inhibiting necroptosis and delaying the progression of NAFLD. Our research offers novel insights into the potential therapeutic applications of GBA3 and FAO in the management and treatment of NAFLD.