Pathogenesis Of Nonalcoholic Fatty Liver Disease Research Articles

Identification and validation of cuproptosis-related genes for diagnosis and therapy in nonalcoholic fatty liver disease.

In recent years, nonalcoholic fatty liver disease (NAFLD) has become a more serious public health issue worldwide. This study strived to investigate the molecular mechanism of pathogenesis of NAFLD and explore promising diagnostic and therapeutic targets for NAFLD. Raw data from GSE130970 were downloaded from the Gene Expression Omnibus database. We used the dataset to analyze the expression levels of cuproptosis-related genes in NAFLD patients and healthy controls to identify the differentially expressed cuproptosis-related genes (DECRGs). The relationship and potential mechanism between DECRGs and clinicopathological factors were examined by enrichment analysis and two consensus clustering methods. We screened key DECRGs based on Random Forest (RF), and then verified the key DECRGs in NAFLD patients, high-fat diet (HFD)-fed mice, and palmitic acid-induced AML12 cells. ROC analysis showed good diagnostic function of DECRGs in normal and NAFLD liver tissue. Two consensus clusters indicated the important role of cuproptosis in the development of NAFLD. We screened for key DECRGs (DLD, DLAT) based on RF and found a close relationship between the DECRGs and clinicopathological factors. We collected clinical blood samples to verify the differences in gene expression levels by qPCR. In addition, we further verified the expression levels of DLD and DLAT in HFD mice and AML12 cells, which showed the same results. This study provides a novel perspective on the pathogenesis of NAFLD. We identified two cuproptosis-related genes that are closely related to NAFLD. These genes may play a significant role in the molecular pathogenesis of NAFLD, which may be useful to make progress in the diagnosis and treatment of NAFLD.

Bacteroides and NAFLD: pathophysiology and therapy.

Non-alcoholic fatty liver disease (NAFLD) is a prevalent chronic liver condition observed globally, with the potential to progress to non-alcoholic steatohepatitis (NASH), cirrhosis, and even hepatocellular carcinoma. Currently, the US Food and Drug Administration (FDA) has not approved any drugs for the treatment of NAFLD. NAFLD is characterized by histopathological abnormalities in the liver, such as lipid accumulation, steatosis, hepatic balloon degeneration, and inflammation. Dysbiosis of the gut microbiota and its metabolites significantly contribute to the initiation and advancement of NAFLD. Bacteroides, a potential probiotic, has shown strong potential in preventing the onset and progression of NAFLD. However, the precise mechanism by which Bacteroides treats NAFLD remains uncertain. In this review, we explore the current understanding of the role of Bacteroides and its metabolites in the treatment of NAFLD, focusing on their ability to reduce liver inflammation, mitigate hepatic steatosis, and enhance intestinal barrier function. Additionally, we summarize how Bacteroides alleviates pathological changes by restoring the metabolism, improving insulin resistance, regulating cytokines, and promoting tight-junctions. A deeper comprehension of the mechanisms through which Bacteroides is involved in the pathogenesis of NAFLD should aid the development of innovative drugs targeting NAFLD.

Comorbidity of periodontal diseases and non-alcoholic fatty liver disease

Among dental pathologies, periodontal diseases occupy the 2nd place in prevalence after caries. The prevalence of non-alcoholic fatty liver disease (NAFLD) in the general population in the world reaches 33.0% and is detected in all age categories. The presence of common risk factors suggests an indirect interaction between periodontitis and NAFLD, but the question of the possibility of direct interaction without the participation of “intermediaries” is relevant. The review examines the bidirectional relationship between periodontal pathology and NAFLD. The results of experimental and clinical studies indicate that periodontal bacteria, especially Porphyromonas gingivalis, correlate with the development of NAFLD. P. gingivalis has been detected in the liver, and LPS from this bacterium has been shown to be involved in the progression of NAFLD, suggesting a possible direct role of P. gingivalis in NAFLD. In addition, P. gingivalis causes disruption of the intestinal microbiocenosis, which contributes to the progression of NAFLD. There are two possible routes connecting the oral cavity and the liver - hematogenous and enteral diffusion of hepatotoxic components. The emerging concept of changes in the oral microbiota associated with periodontitis is closely related to the role of the mouth-gut-liver axis in the pathogenesis of NAFLD, based on the close relationship between the gut and liver connected by the enterohepatic circulation.

Anti-osteoporotic treatments in the era of non-alcoholic fatty liver disease: friend or foe.

Over the last years non-alcoholic fatty liver disease (NAFLD) has grown into the most common chronic liver disease globally, affecting 17-38% of the general population and 50-75% of patients with obesity and/or type 2 diabetes mellitus (T2DM). NAFLD encompasses a spectrum of chronic liver diseases, ranging from simple steatosis (non-alcoholic fatty liver, NAFL) and non-alcoholic steatohepatitis (NASH; or metabolic dysfunction-associated steatohepatitis, MASH) to fibrosis and cirrhosis with liver failure or/and hepatocellular carcinoma. Due to its increasing prevalence and associated morbidity and mortality, the disease-related and broader socioeconomic burden of NAFLD is substantial. Of note, currently there is no globally approved pharmacotherapy for NAFLD. Similar to NAFLD, osteoporosis constitutes also a silent disease, until an osteoporotic fracture occurs, which poses a markedly significant disease and socioeconomic burden. Increasing emerging data have recently highlighted links between NAFLD and osteoporosis, linking the pathogenesis of NAFLD with the process of bone remodeling. However, clinical studies are still limited demonstrating this associative relationship, while more evidence is needed towards discovering potential causative links. Since these two chronic diseases frequently co-exist, there are data suggesting that anti-osteoporosis treatments may affect NAFLD progression by impacting on its pathogenetic mechanisms. In the present review, we present on overview of the current understanding of the liver-bone cross talk and summarize the experimental and clinical evidence correlating NAFLD and osteoporosis, focusing on the possible effects of anti-osteoporotic drugs on NAFLD.

Non-alcoholic fatty liver disease and Helicobacter pylori infection: is there a relationship? Review

The article outlines the relevance of finding a connection between non‑alcoholic fatty liver disease (NAFLD) and Helicobacter pylori infection. The presented data of the majority of studies indicate the presence of Helicobacter pylori infection as a risk factor for the development of NAFLD. In addition, a number of researchers point to the possibility of the influence of Helicobacter pylori on important pathogenetic chains of NAFLD: insulin resistance, the state of the intestinal microbiota, the level of such hormones as ghrelin, leptin, adiponectin, and also that the effect of Helicobacter pylori (H. pylori) toxins can cause direct damage to the liver and that Helicobacter pylori invasion of the small intestine mucosa can increase the permeability of the latter, disrupting the functioning of the gut—liver axis. The article emphasizes the relationship between H. pylori infection and an unfavorable metabolic profile: dyslipidemia, body mass index, blood pressure, fasting blood glucose, and insulin resistance. In addition, research data on the novelty of higher levels of aspartate and alanine aminotransferase in Helicobacter‑positive patients compared to Helicobacter‑negative patients, in the absence of differences in liver fibrosis, are given. Separately, the research data are given, which indicate that the successful eradication of Helicobacter infection does not have a significant effect on liver steatosis, but probably reduces the severity of insulin resistance. Also, the authors draw attention to the fact that in a number of studies, the connection of H. pylori with NAFLD was not found, and no significant differences were found in the levels of high and low‑density lipoprotein cholesterol in people with Helicobacter infection compared to Helicobacter‑negative ones. The authors conclude that today there is no clear understanding of the role of Helicobacter pylori infection in the NAFLD pathogenesis, which requires further research because, after all, most researchers testify in favor of the fact that H. pylori infection can be one of the risk factors, contributing to the emergence and progression of NAFLD, and eradication of H. pylori may be important in the treatment of this disease.

Nanoplastics and chrysene pollution: Potential new triggers for nonalcoholic fatty liver disease and hepatitis, insights from juvenile Siniperca chuatsi

Nanopolystyrene (NP) and chrysene (CHR) are ubiquitous contaminants in the natural environment; however, research on their hepatotoxicity and associated adverse effects remains relatively inadequate. The present study aimed to investigate the hepatotoxic effects of NP and/or CHR at environmentally relevant concentrations, as well as the underlying molecular mechanisms, in juvenile Siniperca chuatsi (mandarin fish). After a 21-day exposure period, the livers of exposed S. chuatsi exhibited macrostructural and microstructural damage accompanied by oxidative stress. Importantly, our study provides the first evidence that NP exposure leads to the development of nonalcoholic fatty liver disease (NAFLD) and hepatitis in S. chuatsi. Similarly, CHR exposure has also been found, for the first time, to cause hepatic sinusoidal dilatation (HSD) and hepatitis. Exposure to the combination of NP and CHR alleviated the symptoms of NAFLD, HSD, and hepatitis. Furthermore, our comprehensive multi-omic analysis revealed that the pathogenesis of NP-induced NAFLD was mainly due to induction of the triglyceride synthesis pathway and inhibition of the very-low-density lipoprotein secretion process. CHR induced HSD primarily through a reduction in vasoprotective ability and smooth muscle contractility. Hepatitis was induced by activation of the JAK-STAT/NF-kappa B signaling pathways, which upregulated the expression of inflammation-specific genes. Collectively, results of this study offer novel insight into the multiple hepatotoxicity endpoints of NP and/or CHR exposure at environmentally relevant concentrations in organisms, and highlight the importance of nanoplastic/CHR pollution for liver health.

PCSK9 dysregulates cholesterol homeostasis and triglyceride metabolism in olanzapine-induced hepatic steatosis via both receptor-dependent and receptor-independent pathways.

Schizophrenia, affecting approximately 1% of the global population, is often treated with olanzapine. Despite its efficacy, olanzapine's prolonged use has been associated with an increased risk of cardiovascular diseases and nonalcoholic fatty liver disease (NAFLD); however, the underlying mechanism remains unclear. Proprotein convertase subtilisin kexin type 9 (PCSK9) plays a crucial role in lipid metabolism and is involved in NAFLD pathogenesis via an unknown mechanism. This study aims to investigate the role of PCSK9 in olanzapine-induced NAFLD. C57BL/6J mice and HepG2 and AML12 cell lines were treated with varying concentrations of olanzapine to examine the effects of olanzapine on PCSK9 and lipid metabolism. PCSK9 levels were manipulated using recombinant proteins, plasmids, and small interfering RNAs invitro, and the effects on hepatic lipid accumulation and gene expression related to lipid metabolism were assessed. Olanzapine treatment significantly increased PCSK9 levels in both animal and cell line models, correlating with elevated lipid accumulation. PCSK9 manipulation demonstrated its central role in mediating hepatic steatosis through both receptor-dependent pathways (impacting NPC1L1) and receptor-independent pathways (affecting lipid synthesis, uptake, and cholesterol biosynthesis). Interestingly, upregulation of SREBP-1c, rather than SREBP-2, was identified as a key driver of PCSK9 increase in olanzapine-induced NAFLD. Our findings establish PCSK9 as a pivotal factor in olanzapine-induced NAFLD, influencing both receptor-related and metabolic pathways. This highlights PCSK9 inhibitors as potential therapeutic agents for managing NAFLD in schizophrenia patients treated with olanzapine.

Exploration of the Key Genes Involved in Non-alcoholic Fatty Liver Disease and Possible MicroRNA Therapeutic Targets

BackgroundMicroRNAs (miRNAs) are promising therapeutic agents for nonalcoholic fatty liver disease (NAFLD). This study aimed to identify key genes/proteins involved in NAFLD pathogenesis and progression and to evaluate miRNAs influencing their expression. MethodsGene expression profiles from datasets GSE151158, GSE163211, GSE135251, GSE167523, GSE46300 and online databases were analyzed to identify significant NAFLD-related genes. Then, protein-protein interaction networks and module analysis identified hub genes/proteins, which were validated using real-time PCR in oleic acid-treated HepG2 cells. Functional enrichment analysis evaluated signaling pathways and biological processes. Gene-miRNA interaction networks identified miRNAs targeting critical NAFLD genes. ResultsThe most critical overexpressed hub genes/proteins included: TNF, VEGFA, TLR4, CYP2E1, ACE, SCD, FASN, SREBF2 and TGFB1 based on PPI network analysis, of which TNF, TLR4, SCD, FASN, SREBF2 and TGFB1 were up-regulated in oleic acid-treated HepG2 cells. Functional enrichment analysis for biological processes highlighted programmed necrotic cell death, lipid metabolic process response to reactive oxygen species, and inflammation. In Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, the highest adjusted P-value signaling pathways encompassed AGE-RAGE in diabetic complications, TNF and HIF-1 signaling pathways. In gene-miRNA network analysis, miR-16 and miR-124 were highlighted as the miRNAs exerting the most influence on important NAFLD-related genes. ConclusionIn silico analyses identified NAFLD therapeutic targets and miRNA candidates to guide further experimental investigation.

Links between gut microbiome, metabolome, clinical variables and non-alcoholic fatty liver disease severity in bariatric patients.

Bacterial species and microbial pathways along with metabolites and clinical parameters may interact to contribute to non-alcoholic fatty liver disease (NAFLD) and disease severity. We used integrated machine learning models and a cross-validation approach to assess this interaction in bariatric patients. 113 patients undergoing bariatric surgery had clinical and biochemical parameters, blood and stool metabolite measurements as well as faecal shotgun metagenome sequencing to profile the intestinal microbiome. Liver histology was classified as normal liver obese (NLO; n = 30), simple steatosis (SS; n = 41) or non-alcoholic steatohepatitis (NASH; n = 42); fibrosis was graded F0 to F4. We found that those with NASH versus NLO had an increase in potentially harmful E. coli, a reduction of potentially beneficial Alistipes putredinis and an increase in ALT and AST. There was higher serum glucose, faecal 3-(3-hydroxyphenyl)-3-hydroxypropionic acid and faecal cholic acid and lower serum glycerophospholipids. In NAFLD, those with severe fibrosis (F3-F4) versus F0 had lower abundance of anti-inflammatory species (Eubacterium ventriosum, Alistipes finegoldii and Bacteroides dorei) and higher AST, serum glucose, faecal acylcarnitines, serum isoleucine and homocysteine as well as lower serum glycerophospholipids. Pathways involved with amino acid biosynthesis and degradation were significantly more represented in those with NASH compared to NLO, with severe fibrosis having an overall stronger significant association with Superpathway of menaquinol-10 biosynthesis and Peptidoglycan biosynthesis IV. In bariatric patients, NASH and severe fibrosis were associated with specific bacterial species, metabolic pathways and metabolites that may contribute to NAFLD pathogenesis and disease severity.

Molecular Insights of Nonalcoholic Fatty Liver Disease Pathogenesis.

Nonalcoholic fatty liver disease (NAFLD) is now the most prevalent chronic liver disease. Many hepatic abnormalities are associated with NAFLD such as nonalcoholic steatohepatitis, progressive fibrosis, cirrhosis, and liver failure. Moreover, the pathogenesis of NAFLD has numerous etiologies and can be explained due to the existence of several of stimulus that act simultaneously on genetically susceptible patients. These stimuli include obesity, diabetes, and insulin resistance. In addition, identifying the role of gut microbiota on NAFLD progression has been illustrated. In this review, we clarified the several factors that lead to the development of NAFLD and identify those who are most at risk of developing liver end-stage disease. Highlighting the noninvasive diagnostic NAFLD markers could be helpful in the disease prevention and treatment approaches.

Macrophage-specific FGFR1 deletion alleviates high-fat-diet-induced liver inflammation by inhibiting the MAPKs/TNF pathways.

Non-alcoholic fatty liver disease (NAFLD) is a common metabolic disease that is substantially associated with obesity-induced chronic inflammation. Macrophage activation and macrophage-medicated inflammation play crucial roles in the development and progression of NAFLD. Furthermore, fibroblast growth factor receptor 1 (FGFR1) has been shown to be essentially involved in macrophage activation. This study investigated the role of FGFR1 in the NAFLD pathogenesis and indicated that a high-fat diet (HFD) increased p-FGFR1 levels in the mouse liver, which is associated with increased macrophage infiltration. In addition, macrophage-specific FGFR1 knockout or administration of FGFR1 inhibitor markedly protected the liver from HFD-induced lipid accumulation, fibrosis, and inflammatory responses. The mechanistic study showed that macrophage-specific FGFR1 knockout alleviated HFD-induced liver inflammation by suppressing the activation of MAPKs and TNF signaling pathways and reduced fat deposition in hepatocytes, thereby inhibiting the activation of hepatic stellate cells. In conclusion, the results of this research revealed that FGFR1 could protect the liver of HFD-fed mice by inhibiting MAPKs/TNF-mediated inflammatory responses in macrophages. Therefore, FGFR1 can be employed as a target to prevent the development and progression of NAFLD.

Exosomal miR-122, miR-128, miR-200, miR-298, and miR-342 as novel diagnostic biomarkers in NAFL/NASH: Impact of LPS/TLR-4/FoxO3 pathway.

Nonalcoholic fatty liver disease (NAFLD) is a common liver disorder affecting a quarter of the global residents. Progression of NAFL into nonalcoholic steatohepatitis (NASH) may cause cirrhosis, liver cancer, and failure. Gut microbiota imbalance causes microbial components translocation into the circulation, triggering liver inflammation and NASH-related fibrosis. MicroRNAs (miRNAs) regulate gene expression via repressing target genes. Exosomal miRNAs are diagnostic and prognostic biomarkers for NAFL and NASH liver damage. Our work investigated the role of the gut microbiota in NAFLD pathogenesis via the lipopolysaccharide/toll-like receptor 4/Forkhead box protein O3 (LPS/TLR-4/FoxO3) pathway and certain miRNAs as noninvasive biomarkers for NAFL or its development to NASH. miRNAexpression levels were measured using quantitative reverse transcription polymerase chain reaction (qRT-PCR) in 50 NAFL patients, 50 NASH patients, and 50 normal controls. Plasma LPS, TLR-4, adiponectin, peroxisome proliferator-activated receptor γ (PPAR-γ), and FoxO3 concentrations were measured using enzyme-linked immunosorbent assay (ELISA). In NAFL and NASH patients, miR-122, miR-128, FoxO3, TLR-4, LPS, and PPAR-γ were upregulated while miR-200, miR-298, miR-342, and adiponectin were downregulated compared with the normalcontrol. The examined miRNAs might distinguish NAFL and NASH patients from the normal controlusing receiver operating characteristic analysis. Our study is the first to examine these miRNAs in NAFLD. Our findings imply that these are potentially promising biomarkers for noninvasive early NAFL diagnosis and NASH progression. Understanding the LPS/TLR-4/FoxO3 pathway involvement in NAFL/NASH pathogenesis may aid disease management.

Association between serum trace element, mineral, and amino acid levels with non-alcoholic fatty liver disease (NAFLD) in adult women

The objective of the present study is assessment of serum trace element and amino acid levels in non-alcoholic fatty liver disease (NAFLD) patients with subsequent evaluation of its independent associations with markers of liver injury and metabolic risk. Materials and methods140 women aged 20–90 years old with diagnosed NAFLD and 140 healthy women with a respective age range were enrolled in the current study. Analysis of serum and hair levels of trace elements and minerals was performed with inductively-coupled plasma mass-spectrometry (ICP-MS). Serum amino acid concentrations were evaluated by high-pressure liquid chromatography (HPLC) with UV-detection. In addition, routine biochemical parameters including liver damage markers, alanine aminotransferase (ALT) and gamma-glutamyltransferase (GGT), were assessed spectrophotometrically. ResultsThe findings demonstrated that patients with NAFLD were characterized by higher ALT, GGT, lactate dehydrogenase (LDH) and cholinesterase (CE) activity, as well as increased levels of total cholesterol, low-density lipoprotein cholesterol, triglycerides, and uric acid. NAFLD patients were characterized by reduced serum and hair Co, Se, and Zn levels, as well as hair Cu content and serum Mn concentrations in comparison to controls. Circulating Ala, Cit, Glu, Gly, Ile, Leu, Phe, and Tyr levels in NAFLD patients exceeded those in the control group. Multiple linear regression demonstrated that serum and hair trace element levels were significantly associated with circulating amino acid levels after adjustment for age, BMI, and metabolic parameters including liver damage markers. ConclusionIt is proposed that altered trace element handling may contribute to NAFLD pathogenesis through modulation of amino acid metabolism.

Immunology of gut microbiome and liver in non-alcoholic fatty liver disease (NAFLD): mechanisms, bacteria, and novel therapeutic targets.

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the world. Most important contributors to its development are diet and obesity. Gut microbiome's importance for immune system and inflammatory pathways more widely accepted as an important component in NAFLD and other liver diseases' pathogenesis. In this article we review potential mechanisms of microbiome alteration of local and systemic immune responses leading to NAFLD's development, and how can modulate them for the treatment. Our review mentions different immune system pathways and microorganisms regulating metabolism, liver inflammation and fibrosis. We specifically point out TLR-4 as a potential key immune pathway activated by bacterial lipopolysaccharides producing pro-inflammatory cytokines in NAFLD. Also, we discuss three endotoxin-producing strains (Enterobacter cloacae B29, Escherichia coli PY102, Klebsiella pneumoniae A7) that can promote NAFLD development via TLR4-dependent immune response activation in animal models and how they potentially contribute to disease progression in humans. Additionally, we discuss their other immune and non-immune mechanisms contributing to NAFLD pathogenesis. In the end we point out gut microbiome researches' future perspective in NAFLD as a potential new target for both diagnostic and treatment.

The upregulation of Annexin A2 by TLR4 pathway facilitates lipid accumulation and liver injury via blocking AMPK/mTOR-mediated autophagy flux during the development of non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide. In this study, we aimed to investigate the role and regulatory mechanism of Annexin A2 (ANXA2) in the pathogenesis of NAFLD. Histological analyses and ELISA were used to illuminate the expression of ANXA2 in NAFLD and healthy subjects. The role of ANXA2 was evaluated using high-fat diet (HFD)-fed mice via vein injection of adeno-associated viruses (AAV) knocking down ANXA2 or non-targeting control (NC) shRNAs. Moreover, HepG2 and LO2 cells were employed as in vitro hepatocyte models to investigate the expression and function of ANXA2. ANXA2 was confirmed to be one of three hub genes in liver injury, and its expression was positively correlated with NAFLD activity score (NAS) and macrophage infiltration in NAFLD. Moreover, ANXA2 was significantly upregulated in NAFLD patients and HFD-fed mice. LPS/TLR4 pathway strongly upregulated ANXA2 expression, which is mediated by direct ANXA2 promoter binding by TLR4 downstream NF-κB p65 and c-Jun transcription factors. Increased ANXA2 expression was correlated with decreased autophagy flux and autophagy was activated by the depletion of ANXA2 in the models of NAFLD. Furthermore, ANXA2 interference led to the activation of AMPK/mTOR signaling axis, which may play a causal role in autophagy flux and the amelioration of steatosis. ANXA2 is a pathological predictor and promising therapeutic target for NAFLD. ANXA2 plays a crucial role in linking inflammation to hepatic metabolic disorder and injury, mainly through the blockage of AMPK/mTOR-mediated lipophagy.

Neutrophils: tissue and circulating signatures of pediatric non-alcoholic fatty liver disease.

The recent rise in non-alcoholic fatty liver disease (NAFLD) among children and adolescents led to a thorough investigation of the peculiarities of the cellular infiltrate which characterize the disease at young ages. This review aims to highlight the key involvement of neutrophils in the pathogenesis of pediatric NAFLD and the potential biomarker role of neutrophil-to-lymphocyte ratio (NLR) in the same pediatric disorder. Neutrophils, which are first responders to inflammation, constitute an abundant component of an infiltrate which is particularly disposed within the portal area of children with NAFLD. The involvement of neutrophils in triggering liver fibrosis has been related amongst others to reactive oxygen species (ROS) production, to the stimulation of hepatic stellate cells, and to their synthesis of neutrophil elastase. As immune imbalance characterizes NAFLD, potentially emerging non-invasive biomarkers such as NLR have been proposed for the detection and prognosis of NAFLD. In adults, several studies asserted the role of NLR in the prediction of advancing liver fibrosis and mortality in subjects with NAFLD. In children, data is scarce with contradicting findings, as some studies failed to identify significant shifting in NLR values in children with NAFLD when compared with obese controls without liver impairment. However, NLR seems to significantly increase in children with obesity and different degrees of NAFLD when compared to healthy counterparts and their changes seem to be reversible with weight loss. Still, paucity of pediatric studies calls for future research addressing the role of NLR in predicting NAFLD development and progression in children with obesity.

Fenofibrate alleviates NAFLD by enhancing the PPARα/PGC-1α signaling pathway coupling mitochondrial function

BackgroundTo comprehend the influences of fenofibrate on hepatic lipid accumulation and mitochondrial function-related signaling pathways in mice with non-alcoholic fatty liver disease (NAFLD) secondary to high-fat diets together with free fatty acids-influenced HepG2 cells model.Materials and methodsA random allocation of male 6-week C57BL/6J mice into three groups was done, including controls, model (14 weeks of a high-fat diet), and fenofibrate [similar to the model one with administered 0.04 g/(kg.d) fenofibrate by gavage at 11 weeks for 4 weeks] groups, which contained 10 mice each. This study verified NAFLD pathogenesis via mitochondrial functions in hepatic pathological abnormalities, liver index and weight, body weight, serum biochemical indexes, oxidative stress indicators, mitochondrial function indexes, and related signaling pathways. The effect of fenofibrate intervention was investigated in NAFLD model mice. In vitro, four groups based on HepG2 cells were generated, including controls, the FFA model (1.5 mmol/L FFA incubation for 24 h), LV-PGC-1α intervention (similar to the FFA model one after PPARGC1A lentivirus transfection), and LV control intervention (similar to the FFA model one after negative control lentivirus transfection) groups. The study investigated the mechanism of PGC-1α related to lipid decomposition and mitochondrial biosynthesis by Oil red O staining, colorimetry and western blot.ResultsIn vivo experiments, a high-fat diet achieved remarkable changes regarding liver weight, liver index, serum biochemical indicators, oxidative stress indicators, liver pathological changes, mitochondrial function indicators, and body weight of the NAFLD model mice while fenofibrate improved the objective indicators. In the HepG2 cells model, the lipid accumulation increased significantly within the FFA model group, together with aggravated hepatocytic damage and boosted oxidative stress levels. Moreover, FFA induced excessive mitosis into fragmented in mitochondrial morphology, ATP content in cells decreased, mtDNA replication fold decreased, the expression of lipid decomposition protein PPARα reduced, mitochondrial biosynthesis related protein PGC-1α, NRF-1 and TFAM decreased. PGC-1α overexpression inhibited lipid deposition by improving mitochondrial biosynthesis and lipid decomposition.ConclusionFenofibrate up-regulated PPARα/PGC-1α signaling pathway, promoted mitochondrial β-oxidation, reduced oxidative stress damage and lipid accumulation of liver. PGC-1α overexpression enhanced mitochondrial biosynthesis and ATP production, and reduced HepG2 intracellular accumulation of lipids and oxidative stress.

Effects of laparoscopic sleeve gastrectomy on nonalcoholic fatty liver disease and TGF-β signaling pathway.

Nonalcoholic fatty liver disease (NAFLD) develops as a result of unhealthy lifestyle but improves with laparoscopic sleeve gastrectomy (LSG). The transforming growth factor (TGF)-β signaling pathway reportedly contributes to liver fibrosis, mainly in animal experiments. The aim of the present study was to evaluate changes in serum proteins before and after LSG by proteomic analysis and to investigate their association with NAFLD. This study enrolled 36 severely obese patients who underwent LSG at our hospital from January 2020 to April 2022. As a pilot study, proteomic analysis was conducted on six patients using serum collected before and at 6 months after LSG, and significantly fluctuating proteins were extracted. Subsequently, verification by enzyme-linked immunosorbent assay (ELISA) using collected serum was performed on the remaining 30 patients. The mean weight of enrolled patients was 118.5 kg. Proteomic analysis identified 1,912 proteins, many of which were related to the TGF-β signaling pathway. Among these proteins, we focused on five TGF-β-related proteins: asporin, EMILIN-1, platelet factor-4, serglycin, and thrombospondin-1. Verification by ELISA revealed that asporin (p = 0.006) and thrombospondin-1 (p = 0.043) levels significantly fluctuated before and after LSG. Univariate analysis with a linear regression model showed that aspartate aminotransferase (p = 0.045), asporin (p = 0.011), and thrombospondin-1 (p = 0.022) levels were significantly associated with postoperative liver fibrosis. On multivariate analysis, asporin was an independent prognostic factor for postoperative liver fibrosis (95% confidence interval: 0.114-1.291, p = 0.002). TGF-β-related proteins dramatically fluctuated before and after LSG and were correlated with NAFLD pathogenesis. Asporin may be a useful prognostic marker of liver fibrosis in NAFLD after LSG.

Loss of LBP triggers lipid metabolic disorder through H3K27 acetylation-mediated C/EBPβ- SCD activation in non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is associated with mutations in lipopolysaccharide-binding protein ( LBP), but the underlying epigenetic mechanisms remain understudied. Herein, LBP -/- rats with NAFLD were established and used to conduct integrative targeting-active enhancer histone H3 lysine 27 acetylation (H3K27ac) chromatin immunoprecipitation coupled with high-throughput and transcriptomic sequencing analysis to explore the potential epigenetic pathomechanisms of active enhancers of NAFLD exacerbation upon LBP deficiency. Notably, LBP -/- reduced the inflammatory response but markedly aggravated high-fat diet (HFD)-induced NAFLD in rats, with pronounced alterations in the histone acetylome and regulatory transcriptome. In total, 1 128 differential enhancer-target genes significantly enriched in cholesterol and fatty acid metabolism were identified between wild-type (WT) and LBP -/- NAFLD rats. Based on integrative analysis, CCAAT/enhancer-binding protein β (C/EBPβ) was identified as a pivotal transcription factor (TF) and contributor to dysregulated histone acetylome H3K27ac, and the lipid metabolism gene SCD was identified as a downstream effector exacerbating NAFLD. This study not only broadens our understanding of the essential role of LBP in the pathogenesis of NAFLD from an epigenetics perspective but also identifies key TF C/EBPβ and functional gene SCD as potential regulators and therapeutic targets.

Chinese medicine in the treatment of non-alcoholic fatty liver disease based on network pharmacology: a review.

Non-alcoholic fatty liver disease (NAFLD) is a clinicopathological syndrome characterized by abnormalities in hepatic fat deposition, the incidence of which has been increasing year by year in recent years. It has become the largest chronic liver disease globally and one of the important causes of cirrhosis and even primary liver cancer formation. The pathogenesis of NAFLD has not yet been fully clarified. Modern medicine lacks targeted clinical treatment protocols for NAFLD, and most drugs lack efficacy and have high side effects. In contrast, Traditional Chinese Medicine (TCM) has significant advantages in the treatment and prevention of NAFLD, which have been widely recognized by scholars around the world. In recent years, through the establishment of a "medicine-disease-target-pathway" network relationship, network pharmacology can explore the molecular basis of the role of medicines in disease prevention and treatment from various perspectives, predicting the pharmacological mechanism of the corresponding medicines. This approach is compatible with the holistic view and treatment based on pattern differentiation of TCM and has been widely used in TCM research. In this paper, by searching relevant databases such as PubMed, Web of Science, and Embase, we reviewed and analyzed the relevant signaling pathways and specific mechanisms of action of single Chinese medicine, Chinese medicine combinations, and Chinese patent medicine for the treatment of NAFLD in recent years. These related studies fully demonstrated the therapeutic characteristics of TCM with multi-components, multi-targets, and multi-pathways, which provided strong support for the exact efficacy of TCM exerted in the clinic. In conclusion, we believe that network pharmacology is more in line with the TCM mindset of treating diseases, but with some limitations. In the future, we should eliminate the potential risks of false positives and false negatives, clarify the interconnectivity between components, targets, and diseases, and conduct deeper clinical or experimental studies.