High-fat Diet-induced Hepatic Steatosis Research Articles

Porcine transient receptor potential channel 1 promotes adipogenesis and lipid deposition

Adipose tissue, an important organ involved in energy metabolism and endocrine, is closely related to animal meat quality and human health. Transient receptor potential channel 1 (TRPC1), an ion transporter, is adipocytes’ major Ca2+ entry channel. However, its function in fat deposition is poorly understood, particularly in pigs, which are both an ideal model for human obesity research and a primary meat source for human diets. In the present investigation, our findings demonstrate a prominent expression of TRPC1 within the adipose tissue of pigs with a strong fat deposition ability. Functional analysis showed that TRPC1 promotes primary preadipocyte proliferation and adipogenic differentiation. In vivo, transgenic mice expressing porcine TRPC1 (Tg-pTRPC1) exhibited aggravated high-fat diet-induced obesity, hepatic steatosis, and insulin resistance. Moreover, TRPC1 may facilitate adipogenesis via activating PI3K/AKT and β-catenin signaling pathways. Our research underscores the pivotal role of porcine TRPC1 as a positive regulator in adipogenesis and lipid accumulation processes, providing a potential target for improving animal meat quality and treating obesity-related diseases in humans.

Clopidogrel ameliorates high-fat diet-induced hepatic steatosis in mice through activation of the AMPK signaling pathway and beyond.

Metabolic dysfunction-associated steatotic liver disease (MASLD) frequently confers an increased risk of vascular thrombosis; however, the marketed antiplatelet drugs are investigated for the prevention and treatment of MASLD in patients with these coexisting diseases. To determine whether clopidogrel could ameliorate high-fat diet (HFD)-induced hepatic steatosis in mice and how it works, mice were fed on normal diet or HFD alone or in combination with or without clopidogrel for 14weeks, and primary mouse hepatocytes were treated with palmitate/oleate alone or in combination with the compounds examined for 24h. Body weight, liver weight, insulin resistance, triglyceride and total cholesterol content in serum and liver, histological morphology, transcriptomic analysis of mouse liver, and multiple key MASLD-associated genes and proteins were measured, respectively. Clopidogrel mitigated HFD-induced hepatic steatosis (as measured with oil red O staining and triglyceride kit assay) and reduced elevations in serum aminotransferases, liver weight, and the ratio of liver to body weight. Clopidogrel downregulated the expression of multiple critical lipogenic (Acaca/Acacb, Fasn, Scd1, Elovl6, Mogat1, Pparg, Cd36, and Fabp4), profibrotic (Col1a1, Col1a2, Col3a1, Col4a1, Acta2, and Mmp2), and proinflammatory (Ccl2, Cxcl2, Cxcl10, Il1a, Tlr4, and Nlrp3) genes, and enhanced phosphorylation of AMPK and ACC. However, compound C (an AMPK inhibitor) reversed enhanced phosphorylation of AMPK and ACC in clopidogrel-treated primary mouse hepatocytes and alleviated accumulation of intracellular lipids. We concluded that clopidogrel may prevent and/or reverse HFD-induced hepatic steatosis in mice, suggesting that clopidogrel could be repurposed to fight fatty liver in patients.

Hepatocyte-specific GDF15 overexpression improves high-fat diet-induced obesity and hepatic steatosis in mice via hepatic FGF21 induction

GDF15 and FGF21, stress-responsive cytokines primarily secreted from the liver, are promising therapeutic targets for metabolic dysfunction-associated steatotic liver disease (MASLD). However, the interaction between GDF15 and FGF21 remains unclear. We examined the effects of hepatocyte-specific GDF15 or FGF21 overexpression in high-fat diet (HFD)-fed mice for 8 weeks. Hydrodynamic injection of GDF15 or FGF21 sustained high circulating levels of GDF15 or FGF21, respectively, resulting in marked reductions in body weight, epididymal fat mass, insulin resistance, and hepatic steatosis. In addition, GDF15 treatment led to early reduction in body weight despite no change in food intake, indicating the role of GDF15 other than appetite loss. GDF15 treatment increased liver-derived serum FGF21 levels, whereas FGF21 treatment did not affect GDF15 expression. GDF15 promoted eIF2α phosphorylation and XBP1 splicing, leading to FGF21 induction. In murine AML12 hepatocytes treated with free fatty acids (FFAs), GDF15 overexpression upregulated Fgf21 mRNA levels and promoted eIF2α phosphorylation and XBP1 splicing. Overall, continuous exposure to excess FFAs resulted in a gradual increase of β-oxidation-derived reactive oxygen species and endoplasmic reticulum stress, suggesting that GDF15 enhanced this pathway and induced FGF21 expression. GDF15- and FGF21-related crosstalk is an important pathway for the treatment of MASLD.

8480 TIX100, a Novel Small Molecule for the Treatment of MASLD/MASH

Abstract Disclosure: S. Jo: None. J. Chen: None. G. Jing: None. K.M. Habegger: None. A. Shalev: Other; Self; TIXiMED, Inc. Founder & CSO. Metabolic dysfunction-associated steatotic liver disease (MASLD) and steatohepatitis (MASH) (aka NAFLD and NASH) affect over 1 billion people worldwide, yet no approved therapy is currently available. MASLD/MASH is often associated with diabetes and obesity and some diabetes medications have shown some beneficial effects in this context. However, beyond steatosis these drugs are in general unable to prevent all the problems associated with MASH, such as inflammation, hepatocyte injury and especially fibrosis. Interestingly, we have now discovered that the new antidiabetic small molecule thioredoxin-interacting protein (TXNIP) inhibitor, TIX100, effectively protects against high-fat diet-induced hepatic steatosis. Oral TIX100 also protected obese and diabetic db/db mice against steatosis and significantly reduced the elevated expression levels of lipogenic genes found in db/db livers, many of which have been shown to be elevated in human MASLD. In addition though, TIX100 also normalized the blood glucose of db/db mice to the levels observed in lean control animals. Therefore, to address the question of whether TIX100 would still be effective in the absence of diabetes, obesity and any genetic leptin-receptor deficiency, we used a validated choline-deficient, amino acid-defined, high-fat diet to induce MASH. Indeed, compared to control chow, this diet significantly increased plasma liver enzymes indicating liver injury without causing diabetes or obesity. It also led to elevated hepatic expression of inflammatory and fibrogenic markers and histology revealed lipid accumulation and steatosis as well as pronounced fibrosis and upregulation of liver macrophages. Excitingly, all these pathological changes were blunted or improved by oral TIX100 treatment. Taken together, oral TIX100 may provide an attractive and effective novel approach for the treatment of MASLD/MASH that goes beyond the correction of diabetes, obesity, and steatosis. Presentation: 6/3/2024

Gut microbiota of miR-30a-5p-deleted mice aggravate high-fat diet-induced hepatic steatosis by regulating arachidonic acid metabolic pathway.

Patients with non-alcoholic fatty liver disease (NAFLD) often exhibit hepatic steatosis and dyslipidemia. Studies have shown that intestinal microorganisms are closely related to the occurrence of NAFLD and atherosclerosis. Our previous study has underscored the protective role of microRNA-30a-5p (miR-30a-5p) against atherosclerosis. In the present study, we aimed to elucidate the effect and underlying mechanism of the intestinal microorganisms of miR-30a-5p knockout (KO) mice on NAFLD. Our findings demonstrated that KO exacerbated high-fat diet (HFD)-induced hepatic steatosis and disrupted liver function, as evidenced by elevated levels of total cholesterol, low-density lipoprotein, alanine aminotransferase, aspartate transaminase, and total bile acids in serum. Fecal microbiota from HFD-fed KO mice induced hepatic steatosis, dyslipidemia, and higher levels of enzymes indicative of liver damage in wild-type mice. Remarkably, KO mice significantly intensified the above effects. 16s rDNA sequencing and metabolomics of the intestinal microbiota in the HFD-treated KO and WT mice showed that the loss of miR-30a-5p resulted in intestinal microbiota imbalance and was highly related to the arachidonic acid metabolic pathway. Targeted metabolomic in the liver tissues unveiled upregulation of COX-related (PGF2a, 8-iso-PGF2a and PGF2) and LOX-related (LTB4, LTD4, 12S-HETE and 15S-HETE) factors in HFD-treated KO mice. Immunohistochemistry and transcriptional analyses showed that miR-30a-5p affected arachidonic acid metabolism through the LOX/COX pathways. Besides, COX/LOX pathways and hepatic steatosis were reversed after reintroducing miR-30a-5p in HFD-treated KO mice. This study reveals the pivotal mechanism by which miR-30a-5p and intestinal microbes regulate hepatic steatosis and abnormal lipid metabolism, offering promising avenues for NAFLD and atherosclerosis therapeutics. MiR-30a-5p deletion aggravated hepatic steatosis and lipid disorder induced by an HFD in mice. Gut microbiota participated in the regulation of hepatic steatosis in the context of miR-30a-5p. Gut microbiota metabolism-related arachidonic acid metabolic pathway contributed to miR-30a-5p-regulated hepatic steatosis and lipid disorder. Reintroducing miR-30a-5p reversed hepatic steatosis and arachidonic acid metabolism disorder caused by HFD and miR-30a-5p deletion.

β-Caryophyllene, a dietary phytocannabinoid, alleviates high-fat diet-induced hepatic steatosis in mice via AMPK activation.

β-Caryophyllene (BCP), a dietary phytocannabinoid, significantly suppresses palmitate-induced lipid accumulation in human HepG2 hepatocytes via activation of AMP-activated protein kinase (AMPK) signaling. The objective of the preset research was to assess whether oral administration of BCP alleviates obesity-induced hepatic steatosis in mice through AMPK activation. We examined the protective action of supplementation of 0.3% BCP (w/w) in a high-fat diet (HFD) on C57BL/6J mice for 12 weeks. BCP supplementation evidently ameliorated histological hepatic steatosis features, and significantly reduced triglycerides and cholesterol levels in the liver, and serum levels of aspartate aminotransferase and alanine aminotransferase as compared with non-supplemented HFD-fed mice. Immunoblotting revealed that BCP supplementation in HFD-fed mice also caused hepatic AMPK activation. Furthermore, treatment with BCP in HFD-fed mice significantly suppressed body weight gain and attenuated obesity-related phenotypes relative to the HFD mice. Our results suggest the usefulness of BCP in the prevention of obesity-related liver steatosis and liver injury.

Dietary medium-chain fatty acids reduce hepatic fat accumulation via activation of a CREBH-FGF21 axis

ObjectiveDietary medium-chain fatty acids (MCFAs), characterized by chain lengths of 8–12 carbon atoms, have been proposed to have beneficial effects on glucose and lipid metabolism, yet the underlying mechanisms remain elusive. We hypothesized that MCFA intake benefits metabolic health by inducing the release of hormone-like factors. MethodsThe effects of chow diet, high-fat diet rich in long-chain fatty acids (LCFA HFD) fed ad libitum or pair-fed to a high-fat diet rich in MCFA (MCFA HFD) on glycemia, hepatic gene expression, circulating fibroblast growth factor 21 (FGF21), and liver fat content in both wildtype and Fgf21 knockout mice were investigated. The impact of a single oral dose of an MCFA-rich oil on circulating FGF21 and hepatic Fgf21 mRNA expression was assessed. In flag-tagged Crebh knockin mice and liver-specific Crebh knockout mice, fed LCFA HFD or MCFA HFD, active hepatic CREBH and hepatic Fgf21 mRNA abundance were determined, respectively. ResultsMCFA HFD improves glucose tolerance, enhances glucose clearance into brown adipose tissue, and prevents high-fat diet-induced hepatic steatosis in wildtype mice. These benefits are associated with increased liver expression of CREBH target genes (Apoa4 and Apoc2), including Fgf21. Both acute and chronic intake of dietary MCFAs elevate circulating FGF21. Augmented hepatic Fgf21 mRNA following MCFA HFD intake is accompanied by higher levels of active hepatic CREBH; and MCFA-induced hepatic Fgf21 expression is blocked in mice lacking Crebh. Notably, while feeding male and female Fgf21 wildtype mice MCFA HFD results in reduced liver triacylglycerol (TG) levels, this liver TG-lowering effect is blunted in Fgf21 knockout mice fed MCFA HFD. The reduction in liver TG levels observed with MCFA HFD was independent of weight loss. ConclusionsDietary MCFAs reduce liver fat accumulation via activation of a CREBH-FGF21 signaling axis.

Integration of Lipidomics and Transcriptomics Identifies the Regulation of Lipid Homeostasis as Potential Mechanisms of Konjac Glucomannan against Hepatic Steatosis.

Hepatic steatosis is characterized by substantial disruption in the liver's lipid level regulation. Konjac glucomannan (KGM) is acknowledged as a nutritious food that has the potential to prevent hyperlipidemia. This study utilized lipidomics and transcriptomics to investigate the efficacy of KGM in alleviating high-fat diet-induced hepatic steatosis by regulating lipid homeostasis. The findings indicated that supplementation of KGM for a duration of 10 weeks led to significant decreases in body weight, liver weight, and epididymal fat tissue weight. Furthermore, improvements in lipid concentrations in plasma and liver samples were observed, along with enhancements in glucose tolerance and the mitigation of liver damage. Additionally, lipidomics analysis revealed that the primary differential lipid metabolites were mainly associated with fatty acid metabolism pathways. Transcriptomic analysis showed that KGM significantly altered the gene expression of the peroxisome proliferator-activated receptor (PPAR) signaling pathway in the liver. Moreover, KGM demonstrated a significant regulatory impact on the hepatic expression of PPARγ, potentially mitigating hepatic steatosis through modulation of the PPARγ-mediated lipid metabolism pathway. In conclusion, these findings suggest that KGM effectively mitigates steatosis by modulating hepatic lipid metabolites and controlling PPARγ-mediated genes in the liver.

Loss of NAT10 alleviates maternal high-fat diet-induced hepatic steatosis in male offspring of mice.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is becoming an escalating health problem in pediatric populations. This study aimed to investigate the role of N-acetyltransferase 10 (NAT10) in maternal high-fat diet (HFD)-induced MASLD in offspring at early life. We generated male hepatocyte-specific NAT10 knockout (Nat10HKO) mice and mated them with female Nat10fl/fl mice under chow or HFD feeding. Body weight, liver histopathology, and expression of lipid metabolism-associated genes (Srebp1c, Fasn, Pparα, Cd36, Fatp2, Mttp, and Apob) were assessed in male offspring at weaning. Lipid uptake assays were performed both in vivo and in vitro. The mRNA stability assessment and RNA immunoprecipitation were performed to determine NAT10-regulated target genes. NAT10 deletion in hepatocytes of male offspring alleviated perinatal lipid accumulation induced by maternal HFD, decreasing expression levels of Srebp1c, Fasn, Cd36, Fatp2, Mttp, and Apob while enhancing Pparα expression. Furthermore, Nat10HKO male mice exhibited reduced lipid uptake. In vitro, NAT10 promoted lipid uptake by enhancing the mRNA stability of CD36 and FATP2. RNA immunoprecipitation assays exhibited direct interactions between NAT10 and CD36/FATP2 mRNA. NAT10 deletion in offspring hepatocytes ameliorates maternal HFD-induced hepatic steatosis through decreasing mRNA stability of CD36 and FATP2, highlighting NAT10 as a potential therapeutic target for pediatric MASLD.

Inhibition of ACOX1 enhances the therapeutic efficacy of obeticholic acid in treating non-alcoholic fatty liver disease and mitigates its lipotoxicity.

High-dose Obeticholic acid exhibits promise for non-alcoholic fatty liver disease (NAFLD) treatment but can induce lipotoxicity. Our study sought to understand this mechanism and propose a solution. In a non-alcoholic fatty liver disease (NAFLD) model induced by a high-fat diet in FXR-/- mice, we pinpointed that FXR regulated the expression of ACOX1 through RNA-Seq analysis. In the livers of FXR-/- mice, both ACOX1 mRNA and protein expression notably decreased. In both HL-7702 and HEP-G2 cells, the silencing of FXR through shRNA plasmids decreased ACOX1 expression, while FXR activation with GW4064 increased it. These effects were reversible with the ACOX1-specific inhibitor, 10,12-Tricosadiynoic acid. In the NAFLD model of FXR-/- mice, The activation of ACOX1 is correlated with elevated serum LDL, triglycerides, and aggravated hepatic steatosis. However, the combination of 10,12-Tricosadiynoic acid with low-dose obeticholic acid effectively treated hepatic steatosis, reducing LDL levels in the NAFLD model of wild-type mice. This combination therapy demonstrated efficacy comparable to high-dose obeticholic acid alone. Notably, the combined drug regimen treats hepatic steatosis by inhibiting the IL-1β and α-SMA pathways in NAFLD. Combining ACOX1-specific inhibitors with low-dose obeticholic acid effectively treats high-fat diet-induced hepatic steatosis and reduces serum LDL. This approach enhances the therapeutic effects of obeticholic acid and mitigates its lipotoxicity by inhibiting the IL-1β and α-SMA pathways.

Repurposing lansoprazole to alleviate metabolic syndrome via PHOSPHO1 inhibition

Drug repurposing offers an efficient approach to therapeutic development. In this study, our bioinformatic analysis first predicted an association between obesity and lansoprazole (LPZ), a commonly prescribed drug for gastrointestinal ulcers. We went on to show that LPZ treatment increased energy expenditure and alleviated the high-fat diet-induced obesity, insulin resistance, and hepatic steatosis in mice. Treatment with LPZ elicited thermogenic gene expression and mitochondrial respiration in primary adipocytes, and induced cold tolerance in cold-exposed mice, suggesting the activity of LPZ in promoting adipose thermogenesis and energy metabolism. Mechanistically, LPZ is an efficient inhibitor of adipose phosphocholine phosphatase 1 (PHOSPHO1) and produces metabolic benefits in a PHOSPHO1-dependent manner. Our results suggested that LPZ may stimulate adipose thermogenesis by inhibiting the conversion of 2-arachidonoylglycerol-lysophosphatidic acid (2-AG-LPA) to 2-arachidonoylglycerol (2-AG) and reduce the activity of the thermogenic-suppressive cannabinoid receptor signaling. In summary, we have uncovered a novel therapeutic indication and mechanism of LPZ in managing obesity and its related metabolic syndrome, and identified a potential metabolic basis by which LPZ improves energy metabolism.

Lacticaseibacillus rhamnosus HF01 fermented yogurt alleviated high-fat diet-induced obesity and hepatic steatosis via the gut microbiota-butyric acid-hepatic lipid metabolism axis.

The objective of this study was to investigate the anti-obesity effects and underlying mechanism of Lacticaseibacillus rhamnosus HF01 fermented yogurt (HF01-Y). Herein, obesity was induced in mice through a high-fat diet and the changes in the gut microbiota were evaluated using 16S rRNA gene sequencing, combined with the expression levels of the liver AMPK signaling pathway to analyze the potential relationship between HF01-Y-mediated gut microbiota and obesity. The results showed that supplementation with HF01-Y improved obesity-related phenotypes in mice, including reduced body weight, improved serum lipid profiles, and decreased hepatic lipid droplet formation. In addition, HF01-Y altered the composition of the gut microbiota in obese mice, significantly upregulated norank_f__Muribaculaceae, unclassified_c__Clostridia, Blautia, unclassified_o__Bacteroidales, and Rikenellaceae_RC9_gut_group, while downregulating unclassified_f__Desulfovibrionaceae, Colidextribacter, and unclassified_f__Oscillospiraceae. These alterations led to an increase of the cecum butyric acid content, which in turn indirectly promoted the activation of the AMPK signaling pathway, subsequently, inhibited fat synthesis, and promoted fatty acid oxidation related gene expression. Therefore, HF01-Y was likely to alleviate hepatic fat and relieve obesity by modulating the gut microbiota-butyric acid-hepatic lipid metabolism axis, ultimately promoting host health.

Mitigation of high-fat diet-induced hepatic steatosis by thyme (Thymus quinquecostatus Celak) polyphenol-rich extract (TPE): insights into gut microbiota modulation and bile acid metabolism.

Our previous study demonstrated that thyme polyphenol-rich extract (TPE) mitigated hepatic injury induced by a high-fat diet (HFD) through the regulation of lipid metabolism, promotion of short-chain fatty acid production, enhancement of intestinal barrier function, and attenuation of inflammation. In this study, we aimed to further elucidate additional mechanisms underlying TPE-mediated preventive effects on hepatic steatosis, with a specific focus on its impact on the gut microbiota and bile acid (BA) metabolism in HFD-fed mice. TPE treatment resulted in a significant reduction in serum total BA levels and a notable increase in fecal total BA levels. In particular, elevations in fecal conjugated BA levels, in turn, impede intestinal farnesoid X receptor (FXR) signaling, thereby enhancing hepatic synthesis and fecal excretion of BAs. The downregulated mRNA expression levels of intestinal Fxr and Fgf15, and hepatic Fgfr4, along with the upregulated mRNA expression levels of Cyp7a1 and Cyp27a1 after TPE treatment also prove the above inference. Meanwhile, TPE appeared to promote BA efflux and enterohepatic circulation, as evidenced by changes in the mRNA levels of Bsep, Ntpc, Shp, Asbt, Ibabp, and Ostα/β. TPE also modulated the gut microbiota and was characterized by an increased relative abundance of Lactobacillus. Furthermore, antibiotic treatment depleted the intestinal flora in mice, also abrogating the hepatoprotective effect of TPE against NAFLD. These findings collectively indicate that TPE effectively mitigates HFD-induced NAFLD by modulating the gut-liver axis, specifically targeting the gut microbiota and bile acid metabolism.

Preventive effects of caffeine on nicotine plus high-fat diet-induced hepatic steatosis and gain weight: a possible explanation for why obese smokers with high coffee consumption tend to be leaner.

Non-alcoholic fatty liver disease (NAFLD) is a prevalent liver disorder, affecting approximately 25 % of the population. Coffee-drinking obese smokers exhibit lower body weights and decreased NAFLD rates, but the reasons behind this remain unclear. Additionally, the effect of nicotine, the main component of tobacco, on the development of NAFLD is still controversial. Our study aimed to explore the possible reasons that drinking coffee could alleviate NAFLD and gain weight and identify the real role of nicotine in NAFLD of obese smokers. A NAFLD model in mice was induced by administering nicotine and a high-fat diet (HFD). We recorded changes in body weight and daily food intake, measured the weights of the liver and visceral fat, and observed liver and adipose tissue histopathology. Lipid levels, liver function, liver malondialdehyde (MDA), superoxide dismutase (SOD), serum inflammatory cytokine levels and the expression of hepatic genes involved in lipid metabolism were determined. Our results demonstrated that nicotine exacerbated the development of NAFLD and caffeine had a hepatoprotective effect on NAFLD. The administration of caffeine could ameliorate nicotine-plus-HFD-induced NAFLD by reducing lipid accumulation, regulating hepatic lipid metabolism, alleviating oxidative stress, attenuating inflammatory response and restoring hepatic functions. Theseresultsmight explainwhyobese smokers with high coffee consumption exhibit the lower incidencerate of NAFLD and tend to be leaner. It is essential to emphasise that the detrimental impact of smoking on health is multifaceted. Smoking cessation remains the sole practical and effective strategy for averting the tobacco-related complications and reducing the risk of mortality.

Hepatic Huwe1 loss protects mice from non-alcoholic fatty liver disease through lipid metabolic rewiring

Non-alcoholic fatty liver disease (NAFLD) is the most pervasive liver pathology worldwide. Here, we demonstrate that the ubiquitin E3 ligase Huwe1 is vital in NAFLD pathogenesis. Using mass spectrometry and RNA sequencing, we reveal that liver-specific deletion of Huwe1 (Huwe1LKO) in 1-year-old mice (approximately middle age in humans) elicits extensive lipid metabolic reprogramming that involves downregulation of de novo lipogenesis and fatty acid uptake, upregulation of fatty acid β-oxidation, and increased oxidative phosphorylation. ChEA transcription factor prediction analysis inferred these changes result from attenuated PPARɑ, LXR, and RXR activity in Huwe1LKO livers. Consequently, Huwe1LKO mice fed chow diet exhibited significantly reduced hepatic steatosis and superior glucose tolerance compared to wild-type mice. Huwe1LKO also conferred protection from high-fat diet-induced hepatic steatosis by 6-months of age, with increasingly robust differences observed as mice reached middle age. Together, we present evidence that Huwe1 plays a critical role in the development of age- and diet-induced NAFLD.

Hepatobiliary and pancreatic: Multi-donor fecal microbiota transplantation attenuated high-fat diet-induced hepatic steatosis in mice by remodeling the gut microbiota.

Fecal microbiota transplantation (FMT) can improve the symptoms of nonalcoholic fatty liver disease (NAFLD) by restoring the gut microbiota. This study was aimed to evaluate the therapeutic effects of single-donor (SD) or multi-donor (MD) FMT in a mouse model of hepatic steatosis and explore the underlying mechanisms. Fecal samples were collected from NAFLD patients and healthy controls with similar baseline characteristics, with gut microbiota analyzed. Mice were fed either a normal-chow diet (NCD) or a high-fat diet (HFD) for 3weeks and then administered fecal microbiota collected from healthy SDs or MDs for 12weeks. Fecal samples from NAFLD patients showed significantly lower microbial diversity than those from healthy controls. MD-FMT reduced liver fat accumulation and body weight and significantly improved serum and liver biochemical indices in HFD-fed mice. Compared to untreated HFD-fed mice, MD-FMT significantly decreased the relative expression of IL-1β, IL-6, TNF-α, IFN-γ, and IL-1β mRNAs in the liver. The relative protein level of intestinal barrier components, including claudin-1, occludin, and E-cadherin, as well as serum lipopolysaccharide (LPS) level in mice, were found to be improved following MD-FMT intervention. Furthermore, FMT reversed HFD-induced gut dysbiosis and increased the abundance of beneficial bacteria such as Blautia and Akkermansia. NAFLD patients and healthy controls showed distinct gut microbiota. Likewise, HFD altered gut microbiota in mice compared to NCD-fed controls. MD-FMT restored gut dysbiosis in HFD-fed mice and attenuated liver steatosis, and should be considered as an effective treatment option for NAFLD.

Protective Effects of Gnetin C from Melinjo Seed Extract against High-Fat Diet-Induced Hepatic Steatosis and Liver Fibrosis in NAFLD Mice Model.

Nonalcoholic fatty liver disease (NAFLD), the most common form of chronic liver disease, can progress to hepatic steatosis, inflammation, and advanced fibrosis, increasing the risk of cirrhosis. Resveratrol, a natural polyphenol with antioxidant and anti-inflammatory properties, is beneficial in treating multiple metabolic diseases. Gnetin C, a resveratrol derivative obtained from Melinjo seed extract (MSE), shares similar health-promoting properties. We investigated the role of gnetin C in preventing NAFLD in a mouse model and compared it with resveratrol. Male C57BL/6J mice were fed a control diet (10% calories from fat), a high-fat choline-deficient (HFCD) diet (46% calories from fat) and HFCD diet supplemented with gnetin C (150 mg/kg BW·day-1) or resveratrol (150 mg/kg BW·day-1) for 12 weeks. Gnetin C supplementation reduced body and liver weight, and improved blood glucose levels and insulin sensitivity. Both gnetin C- and resveratrol reduced hepatic steatosis, with gnetin C also decreasing liver lipid content. Gnetin C and resveratrol ameliorated HFCD diet-induced hepatic fibrosis. The mRNA expression results, and western blot analyses showed that gnetin C and, to some extent, resveratrol downregulated fibrosis markers in the TGF-β1 signaling pathway, indicating a possible safeguarding mechanism against NAFLD. These results suggest that gnetin C supplementation may protect against lipid deposition and hepatic fibrosis.

Protective Effects of Melatonin in High-Fat Diet-Induced Hepatic Steatosis via Decreased Intestinal Lipid Absorption and Hepatic Cholesterol Synthesis.

The preventative effect of melatonin on the development of obesity and the progression of fatty liver under a high-fat diet (HFD) has been well elucidated through previous studies. We investigated the mechanism behind this effect regarding cholesterol biosynthesis and regulation of cholesterol levels. Mice were divided into three groups: normal chow diet (NCD); HFD; and HFD and melatonin administration group (HFD+M). We assessed the serum lipid profile, mRNA expression levels of proteins involved in cholesterol synthesis and reabsorption in the liver and nutrient transporters in the intestines, and cytokine levels. Additionally, an in vitro experiment using HepG2 cells was performed. Expression of hepatic sterol regulatory element-binding protein 2 (SREBP-2), 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR), and low-density lipoprotein receptor (LDLR) demonstrated that melatonin administration significantly reduces hepatic cholesterol synthesis in mice fed an HFD. Expression of intestinal sodium-glucose transporter 1 (SGLT1), glucose transporter 2 (GLUT2), GLUT5, and Niemann-pick C1-like 1 (NPC1L1) demonstrated that melatonin administration significantly reduces intestinal carbohydrate and lipid absorption in mice fed an HFD. There were no differences in local and circulatory inflammatory cytokine levels among the NCD, HFD, and HFD+M group. HepG2 cells stimulated with palmitate showed reduced levels of SREBP, LDLR, and HMGCR indicating these results are due to the direct mechanistic effect of melatonin on hepatocytes. Collectively, these data indicate the mechanism behind the protective effects of melatonin from weight gain and liver steatosis under HFD is through a reduction in intestinal caloric absorption and hepatic cholesterol synthesis highlighting its potential in the treatment of obesity and fatty liver disease.

Tuberostemonine alleviates high-fat diet-induced obesity and hepatic steatosis by increasing energy consumption

Obesity is of public concern worldwide, and it increases the probability of developing a number of comorbid diseases, including NAFLD. Recent research on obesity drugs and health demands have shown the potential of natural plant extracts for preventing and treating obesity and their lack of toxicity and treatment-related side effects. We have demonstrated that tuberostemonine (TS), an alkaloid extracted from the traditional Chinese medicine Stemona tuberosa Lour can inhibit intracellular fat deposition, reduce oxidative stress, increase cellular adenosine triphosphate (ATP), and increase mitochondrial membrane potential. It effectively reduced weight gain and fat accumulation caused by a high-fat diet, and regulated liver function and blood lipid levels. Moreover, it regulate glucose metabolism and improved energy metabolism in mice. TS also decreased high-fat diet-induced obesity and improved lipid and glucose metabolism disorders in mice, with no significant side effects. In conclusion, TS was shown to be a safe alternative for obese patients and might be developed as an antiobesity and anti-nonalcoholic fatty liver drug.

Tripartite motif 38 alleviates the pathological process of NAFLD–NASH by promoting TAB2 degradation

Nonalcoholic fatty liver disease (NAFLD) has become the most prevalent chronic liver disease worldwide, without any Food and Drug Administration-approved pharmacological intervention in clinic. Trim38, as an important member of the TRIM (tripartite motif-containing) family, was largely reported to be involved in the regulation of innate immune and inflammatory responses. However, the functional roles of TRIM38 in NAFLD remain largely unknown. Here, the expression of TRIM38 was first detected in liver samples of both NAFLD mice model and patients diagnosed with NAFLD. We found that TRIM38 expression was downregulated in NAFLD liver tissues compared with normal liver tissues. Genetic Trim38-KO in vivo showed that TRIM38 depletion deteriorated the high-fat diet and high fat and high cholesterol diet-induced hepatic steatosis and high fat and high cholesterol diet-induced liver inflammation and fibrosis. In particular, we found that the effects of hepatocellular lipid accumulation and inflammation induced by palmitic acid and oleic acid were aggravated by TRIM38 depletion but mitigated by TRIM38 overexpression in vitro. Mechanically, RNA-Seq analysis demonstrated that TRIM38 ameliorated nonalcoholic steatohepatitis progression by attenuating the activation of MAPK signaling pathway. We further found that TRIM38 interacted with transforming growth factor-β-activated kinase 1 binding protein 2 and promoted its protein degradation, thus inhibiting the transforming growth factor-β-activated kinase 1-MAPK signal cascades. In summary, our study revealed that TRIM38 could suppress hepatic steatosis, inflammatory, and fibrosis in NAFLD via promoting transforming growth factor-β-activated kinase 1 binding protein 2 degradation. TRIM38 could be a potential target for NAFLD treatment.