Nonalcoholic Fatty Liver Disease In Mice Research Articles

Zhimu-Huangbai herb-pair ameliorates hepatic steatosis in mice by regulating IRE1α/XBP1s pathway to inhibit SREBP-1c

BackgroundCurrently, there is a lack of validated pharmacological interventions for non-alcoholic fatty liver disease (NAFLD), which is characterized by the accumulation of hepatic triglyceride. Zhimu-Huangbai (ZH) herb-pair is a traditional Chinese medicine that regulates glucose and lipid metabolism disorders. However, the precise mechanisms underlying the preventive effects of hepatic triglyceride induced by high-fat diet (HFD) remain elusive. PurposeThe study aimed to examine the impact of ZH herb-pair on NAFLD in mice and explore the underlying mechanisms, particularly its effects on endoplasmic reticulum (ER) stress and lipid metabolism. MethodsNAFLD was induced in mice using HFD, and the treated mice were orally administered ZH, metformin (Glucophage) or lovastatin. The lipid metabolism factors, ER stress markers, and the unfolded protein response (UPR) branch factors were measured using immunohistochemistry, western blotting or qRT-PCR. Co-Immunoprecipitation (CoIP) was performed to reveal the connection between SCAP and SREBP-1c. Tunicamycin (TM) and plasmid delivery were used to induce acute ER stress or crease XBP1 gain function models. The main compounds in ZH binding to IRE1α protein were studied by molecular docking and cellular thermal shift assay (CETSA). ResultsTreatment with ZH significantly ameliorated hepatic steatosis and reduced lipid synthesis process mainly inhibiting the expression of mature active form of SREBP-1c through relieving ER stress. The expression of IRE1α and XBP1s was inhibited after treatment with ZH. In addition, ZH improved the fatty liver phenotype caused by XBP1 overexpression via decreasing srebp1c transcription. In vitro experimental results suggested that the main compounds in ZH decreased cellular TG contents. Mechanistically, ZH targeted IRE1α and inhibited XBP1s mRNA expression to relieve ER stress and inhibit SREBP-1c production. ConclusionsZH herb-pair can protect against NAFLD by reducing the expression of SREBP-1c, in part, via regulating IRE1α/XBP1s pathway.

Western Diet-Induced Nonalcoholic Fatty Liver Disease Mice Mimic the Key Transcriptomic Signatures Observed in Humans

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease characterized by the accumulation of fat in the liver in the absence of excessive alcohol consumption or a secondary cause of hepatic steatosis. The prevalence of NAFLD is increasing worldwide and its management has become a public health concern. Animal models are traditionally used to elucidate disease mechanisms and identify potential drug targets; however, their translational aspects in human diseases have not been fully established. This study aimed to clarify the utility of animal models for translational research by assessing their relevance to human diseases using gene expression analysis. Weighted gene co-expression network analysis of liver tissues from Western diet (WD)-induced NAFLD mice was performed to identify the modules associated with disease progression. Moreover, the similarity of the gene co-expression network across species was evaluated using module preservation analysis. Nineteen disease-associated modules were identified. The brown module was positively associated with disease severity, and functional analyses indicated that it may be involved in inflammatory responses in immune cells. Moreover, the gene co-expression network of the brown module was highly preserved in human NAFLD liver gene expression datasets. These results indicate that WD-induced NAFLD mice have similar gene co-expression networks (especially genes associated with inflammatory responses) to humans and are thought to be a useful experimental tool for preclinical research on NAFLD.

Polysaccharide of Atractylodes macrocephala Koidz alleviates NAFLD-induced hepatic inflammation in mice by modulating the TLR4/MyD88/NF-κB pathway

Non-alcoholic fatty liver disease (NAFLD) not only could cause abnormal lipid metabolism in the liver, but also could cause liver inflammation. Previous studies have shown that Polysaccharide of Atractylodes macrocephala Koidz (PAMK) could alleviate animal liver inflammatory damage and alleviate NAFLD in mice caused by high-fat diet(HFD), but regulation of liver inflammation caused by NAFLD has rarely been reported. In this study, an animal model of non-alcoholic fatty liver inflammation in the liver of mice was established to explore the protective effect of PAMK on the liver of mice. The results showed that PAMK could alleviate the abnormal increase of body weight and liver weight of mice caused by HFD, alleviate the abnormal liver structure of mice, reduce the level of oxidative stress and cytokine secretion in the liver of mice, and downregulate the mRNA expression of TLR4, MyD88, NF-κB and protein expression of P-IκB, P-NF-κB-P65, TLR4, MyD88, NF-κB in the liver. These results indicate that PAMK could alleviate hepatocyte fatty degeneration and damage, oxidative stress and inflammatory response of the liver caused by NAFLD in mice.

Exploration of the potential mechanism of aqueous extract of Artemisia capillaris for the treatment of non-alcoholic fatty liver disease based on network pharmacology and experimental verification.

Non-alcoholic fatty liver disease (NAFLD) is a nutritional and metabolic disease with a high prevalence today. Artemisia capillaris has anti-inflammatory, antioxidant, and other effects. However, the mechanism of A. capillaris in treating NAFLD is still poorly understood. This study explored the mechanism of A. capillaris in the treatment of NAFLD through network pharmacology and molecular docking, and verified the results through in vivo experiments using a high-fat diet-induced mouse model and in vitro experiments using an oleic acid-induced HepG2 cell model. Aqueous extract of A. capillaris (AEAC) can reduce blood lipids, reduce liver lipid accumulation and liver inflammation in NAFLD mice, and improve NAFLD. Network pharmacology analysis revealed that 51 drug ingredients in A. capillaris correspond to 370 targets that act on NAFLD. GEO data mining obtained 93 liver differentially expressed genes related to NAFLD. In the UHPLC-MS detection results, 36 components were characterized and molecular docked with JNK. Verified in vitro and in vivo, the results show that JNK and the phosphorylation levels of IL-6, IL-1β, c-Jun, c-Fos, and CCL2 are key targets and pathways. This study confirmed that AEAC reduces lipid accumulation and inflammation in the liver of NAFLD mice by inhibiting the JNK/AP-1 pathway.

Chemically synthesized osteocalcin alleviates NAFLD via the AMPK-FOXO1/BCL6-CD36 pathway

Nonalcoholic fatty liver disease (NAFLD) is a common chronic liver disease worldwide. Osteocalcin plays an important role in energy metabolism. In this study, we investigated the mechanism of action of chemically synthesized osteocalcin (csOCN) in ameliorating NAFLD. We demonstrated for the first time that csOCN attenuates lipid accumulation in the liver and hepatocytes by modulating CD36 protein expression. In addition, we found that the expression of p-AMPK, FOXO1 and BCL6 decreased and the expression of CD36 increased after OA/PA induction compared to the control group, and these effects were reversed by the addition of csOCN. In contrast, the therapeutic effect of csOCN was inhibited by the addition of AMPK inhibitors and BCL6 inhibitors. This finding suggested that csOCN regulates CD36 expression via the AMPK-FOXO1/BCL6 axis. In NAFLD mice, oral administration of csOCN also activated the AMPK pathway and reduced CD36 expression. Molecular docking revealed that osteocalcin has a docking site with CD36. Compared to oleic acid and palmitic acid, osteocalcin bound more strongly to CD36. Laser confocal microscopy results showed that osteocalcin colocalized with CD36 at the cell membrane. In conclusion, we demonstrated the regulatory role of csOCN in fatty acid uptake pathways for the first time; it regulates CD36 expression via the AMPK-FOXO1/BCL6 axis to reduce fatty acid uptake, and it affects fatty acid transport by may directly binding to CD36. There are indications that csOCN has potential as a CD36-targeted drug for the treatment of NAFLD.

Investigation of the Hepatitis-B Vaccine's Immune Response in a Non-Alcoholic Fatty Liver Disease Mouse Model.

This study aimed to investigate the immunogenicity of the hepatitis B virus (HBV) vaccine by applying a normal and high-dose hepatitis B virus vaccination program in the mice modeling of non-alcoholic fatty liver disease (NAFLD). NAFLD was induced in mouse livers via diet. At the 10-week mark, both groups were divided into 3 subgroups. While the standard dose vaccination program was applied on days 0, 7, and 21, two high-dose programs were applied: one was applied on days 0 and 7, and the other was applied on days 0, 7, and 21. All mice were euthanized. Blood samples from anti-HB titers; T follicular helper, T follicular regulatory, CD27+, and CD38+ cells; and the liver, spleen, and thymus were taken for histopathologic evaluation. NAFLD subgroups receiving high doses showed higher hepatocyte ballooning scores than normal-dose subgroup. There were differences in CD27+ and CD27+CD38+ cells in animals fed on different diets, without any differences or interactions in terms of vaccine protocols. In the NAFLD group, a negative correlation was observed between anti-HB titers and T helper and CD27+ cells, while a positive correlation was observed with CD38+ cells. NAFLD induced changes in immune parameters in mice, but there was no difference in vaccine efficacy among the applied vaccine protocols. Based on this study's results, high-dose vaccination protocols are not recommended in cases of NAFLD, as they do not enhance efficacy and may lead to increased liver damage.

Amelioration of nonalcoholic fatty liver disease by inhibiting the deubiquitylating enzyme RPN11

Nonalcoholic fatty liver disease (NAFLD), including its more severe manifestation nonalcoholic steatohepatitis (NASH), is a global public health challenge. Here, we explore the role of deubiquitinating enzyme RPN11 in NAFLD and NASH. Hepatocyte-specific RPN11 knockout mice are protected from diet-induced liver steatosis, insulin resistance, and steatohepatitis. Mechanistically, RPN11 deubiquitinates and stabilizes METTL3 to enhance the m6A modification and expression of acyl-coenzyme A (CoA) synthetase short-chain family member 3 (ACSS3), which generates propionyl-CoA to upregulate lipid metabolism genes via histone propionylation. The RPN11-METTL3-ACSS3-histone propionylation pathway is activated in the livers of patients with NAFLD. Pharmacological inhibition of RPN11 by Capzimin ameliorated NAFLD, NASH, and related metabolic disorders in mice and reduced lipid contents in human hepatocytes cultured in 2D and 3D. These results demonstrate that RPN11 is a novel regulator of NAFLD/NASH and that suppressing RPN11 has therapeutic potential for the treatment.

Effect of Ilex hainanensis Merr. On HFD-induced nonalcoholic fatty liver disease and rebalance of gut microbiota and bile acids metabolism in mice

Nonalcoholic fatty liver disease (NAFLD) is a clinicopathological syndrome characterized by excessive intracellular fat deposition in the hepatocytes, and the development is exacerbated by gut microbiota and bile acids metabolism disorders. Ilex hainanensis Merr. is a traditional medicine of the Zhuang nationality, historically esteemed for its efficacy in lowering blood pressure and lipid levels. This study aimed to investigate the pharmacodynamic effects in NAFLD mice and impacts on gut microbiota and bile acids (BAs) metabolism of I. hainanensis extract (IHA). 16 compounds were identified from IHA by HPLC-DAD-MS analysis. IHA significantly reduced body weight indexs, alanine transaminase (ALT) and aspartate transaminase (AST) activities, improved dyslipidemia and insulin resistance (IR), and effectively ameliorated hepatic steatosis in HFD-induced NAFLD mice. IHA also altered gut microbiota composition, particularly enhancing the abundance of bacteria involved in BAs metabolism, as well as augmented BAs synthesis in the liver and increased fecal excretion. In conclusion, our findings suggest that IHA holds promise in improving NAFLD conditions and modulating gut microbiota and BAs metabolism. These insights contribute to a deeper understanding of the mechanisms underlying IHA-mediated alleviation of lipid accumulation in NAFLD.

Exploring the effect and mechanism of Hippophae rhamnoides L. triterpenoid acids on improving NAFLD based on network pharmacology and experimental validation in vivo and in vitro

Ethnopharmacological relevanceSea buckthorn (Hippophae rhamnoides L.) is a traditional Chinese medicinal and possesses a rich medical history in terms of treating gastric disorders, sputum and cough and liver injuries in oriental medicinal system. By reason of the complicated chemical constituents, the material basis and potential pharmacological mechanism of sea buckthorn acting on Non-alcoholic fatty liver disease (NAFLD) has not been clearly elucidated. Aim of the studyTo explore the pharmacological efficacy and underlying mechanism of sea buckthorn triterpenoid acid enrichment (STE) in the treatment of NAFLD. Materials and methodsThe approaches of Network pharmacology and experiment validation in vitro and in vivo were applied in this study. Firstly, targets of triterpenoid acid compounds and NAFLD were collected from databases. The crucial targets were screened by the construction of protein-protein interaction (PPI) network. Furthermore, the potential signaling pathways and targets affected by STE was predicted by GO together with KEGG enrichment analysis. Finally, the experiment validation was carried out through high-fat feeding NAFLD mice and lipid accumulation HepG2 cell model. Lipids and liver related biochemical indicators were determined, Oil Red O and H&E staining were employed to observe fat accumulation. In addition, the expression levels of proteins of key target and signal pathway anticipated in network pharmacology were detected to elaborated its action mechanism. ResultsA total of 180 intersecting potential targets for enhancing NAFLD with STE were eventually identified. 6 key targets including AKT1, TNF, IL6, INS, JUN, STAT3 and TP53 were further identified and the AMPK-SREBP1 pathway was enriched. Animal experiment result showed that STE treatment could significantly reduce the levels of TG, TC, LDL-C, ALT and AST, increase the levels of HDL-C in serum, and improve lipid accumulation of epididymal fat and liver. The results of the lipid accumulation cell model indicated that STE and key compound oleanolic acid could diminish intracellular lipid levels of TG, TC, LDL-C and number of lipid droplets. Western blot results showed that the above beneficial effects could be achieved by regulating the expression of p-AMPK/AMPK, SREBP1, FAS, ACC, SCD protein. ConclusionThis study confirmed the effect of STE on improving NAFLD and the potential action mechanism was involved in the regulation of the AMPK-SREBP1 pathway.

Chiglitazar attenuates high-fat diet-induced nonalcoholic fatty liver disease by modulating multiple pathways in mice

Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases worldwide; however, effective intervention strategies for NAFLD are still unavailable. The present study sought to investigate the efficacy of chiglitazar, a pan-PPAR agonist, in protecting against NAFLD in mice and its underlying molecular mechanism. Male C57BL/6 J mice were fed a high-fat diet (HFD) for 8 weeks to generate NAFLD and the HFD was continued for an additional 10 weeks in the absence or presence of 5 mg/kg/d or 10 mg/kg/d chiglitazar by gavage. Chiglitazar significantly improved dyslipidemia and insulin resistance, ameliorated hepatic steatosis and reduced liver inflammation and oxidative stress in NAFLD mice. RNA-seq revealed that chiglitazar alleviated HFD-induced NAFLD in mice through multiple pathways, including fatty acid metabolism regulation, insulin signaling pathway, and AMPK signaling pathway. This study demonstrated the potential therapeutic effect of chiglitazar on NAFLD. Chiglitazar ameliorated NAFLD by modulating multiple pathways.

Exploring the Impact of the Liver-Intestine-Brain Axis on Brain Function in Non-Alcoholic Fatty Liver Disease

This study investigates the molecular complexities of Non-alcoholic Fatty Liver Disease (NAFLD)-induced brain dysfunction, with a focus on the liver-intestine-brain axis and potential therapeutic interventions. The main objectives include understanding critical microbiota shifts in NAFLD, exploring altered metabolites, and identifying key regulatory molecules influencing brain function. The methods employed encompassed 16S rRNA sequencing to scrutinize stool microbiota in NAFLD patients and healthy individuals, non-targeted metabolomics using LC-MS to uncover elevated levels of deoxycholic acid (DCA) in NAFLD mice, and single-cell RNA sequencing to pinpoint the pivotal gene Hpgd in microglial cells and its downstream janus kinase 2/signal transducer and activator of transcription 3 (Jak2/Stat3) signaling pathway. Behavioral changes and brain function were assessed in NAFLD mice with and without Fecal Microbiota Transplantation (FMT) treatment, utilizing various assays and analyses. The results revealed significant differences in microbiota composition, with increased levels of Bacteroides in NAFLD patients. Additionally, elevated DCA levels were observed in NAFLD mice, and FMT treatment demonstrated efficacy in ameliorating liver function and brain dysfunction. Hpgd inhibition by DCA activated the Jak2/Stat3 pathway in microglial cells, leading to inflammatory activation, inhibition of mitochondrial autophagy, induction of neuronal apoptosis, and reduction in neuronal action potentials. This study elucidates the intricate molecular mechanisms underlying the liver-gut-brain axis in NAFLD, and the identification of increased DCA and the impact of Jak2/Stat3 signaling on microglial cells highlight potential therapeutic targets for addressing NAFLD-induced brain dysfunction.

A preclinical model of severe NASH-like liver injury by chronic administration of a high-fat and high-sucrose diet in mice

Non-alcoholic fatty liver disease (NAFLD) is a progressive liver disease, affecting 38% of adults globally. If left untreated, NAFLD may progress to more advanced forms of the disease, including non-alcoholic steatohepatitis (NASH), liver cirrhosis, and fibrosis. Early NAFLD detection is critical to prevent disease progression. Using an obesogenic high-fat and high-sucrose (HF/HS) diet, we characterized the progression of NAFLD in male and female Collaborative Cross CC042 mice after 20-, 40-, and 60-week intervals of chronic HF/HS diet feeding. The incidence and severity of liver steatosis, inflammation, and fibrosis increased in both sexes over time, with male mice progressing to a NASH-like disease state faster than female mice, as indicated by earlier and more pronounced changes in liver steatosis. Histopathological indication of macrovesicular steatosis and gene expression changes of key lipid metabolism genes were found to be elevated in both sexes after 20 weeks of HF/HS diet. Measurement of circulating markers of inflammation (CXCL10 and TNF-α), histopathological analysis of immune cell infiltrates, and gene expression changes in inflammation-related genes indicated significant liver inflammation after 40 and 60 weeks of HF/HS diet exposure in both sexes. Liver fibrosis, as assessed by Picosirius red and Masson's trichrome staining and changes in expression of key fibrosis related genes indicated significant changes after 40 and 60 weeks of HF/HS diet exposure. In conclusion, we present a preclinical animal model of dietary NAFLD progression, which recapitulates human pathophysiological and pathomorphological changes, that could be used to better understand the progression of NAFLD and support development of new therapeutics.

Regulatory effect of Diwu Yanggan Decoction on lysoglycerophospholipids in circulating exosomes in a mouse model of nonalcoholic fatty liver disease

To evaluate the regulatory effect of Diwu Yanggan (DWYG) Decoction on lysoglycerophospholipids (Lyso-GPLs) in circulating exosomes in a mouse model of nonalcoholic fatty liver disease (NAFLD). Circulating exosomes isolated from mouse serum by size exclusion chromatography were morphologically characterized using transmission electron microscope and examined for surface markers CD9, CD63 and TSG101 using Western blotting. Twenty-four male Kunming mice were randomized into 3 groups for normal feeding (control, n=8) or high-fat diet feeding for 1 week to induce NAFLD, after which the latter mice were given DWYG decoction (treatment group, n=8) or normal saline (model group, n=8) by gavage for 4 weeks. After the last treatment, blood samples were collected from the mice for testing serum TC, HDL-C, LDL-C, ALT and AST levels and isolating circulating exosomes. Using multivariate statistical analysis based on targeted metabolomics strategy, the potential biomarkers for Lyso-GPLs in the exosomes were screened. The isolated exosomes about 100 nm in size had a typical saucer-like structure with distinct double-layer membranes and a mean particle size of 137.5 nm and expressed the specific surface marker proteins CD9, CD63 and TSG101. The mouse models of NAFLD had significantly increased serum levels of TC, HDL-C, LDL-C and AST and lowered serum ALT level. A total of 43 Lyso-GPLs with significant reduction after DWYG Decoction treatment were identified in NAFLD mice. DWYG Decoction can regulate Lyso-GPLs in circulating exosomes in NAFLD mice, which provides a new clue for studying the therapeutic mechanism of DWYG Decoction for liver disease.

Effect of Rab18 on liver injury and lipid accumulation by regulating perilipin 2 and peroxisome proliferator-activated receptor gamma in non-alcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is currently one of the most common chronic liver diseases worldwide, characterized by the presence of lipid droplets. Rab18 is an important lipid droplet protein; however, its effects and mechanisms of action on NAFLD remain unclear. Free fatty acid-stimulated AML-12 cells and high-fat diet (HFD)-fed mice were used as NAFLD models. Lentiviruses overexpressing Rab18 (Rab18-OE) or knockdown (Rab18-KD) were used to generate stable cell lines for genetic analysis. Blood serum levels of alanine aminotransferase, aspartate aminotransferase, total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, glucose, and leptin were measured using a biochemical autoanalyzer. Hematoxylin and eosin staining was performed to detect pathological damage to the liver. Lipid accumulation in the cells was assessed by Oil Red O staining. Target expression was measured using qPCR, western blotting, and immunocytochemistry. Rab18 mRNA and protein expression levels increased in free fatty acid-stimulated AML-12 cells and the livers of HFD-fed mice. Rab18-OE increased lipid accumulation in vitro, which was attenuated by Rab18-KD. In vivo, Rab18-OE augmented liver pathological damage, serum alanine aminotransferase/aspartate aminotransferase activity, and triglyceride, total cholesterol, and low-density lipoprotein levels, whereas Rab18-KD decreased these indicators. Rab18-KD also downregulated blood glucose levels in HFD-fed mice. Mechanistically, Rab18-OE and Rab18-KD regulated the mRNA and protein expression levels of perilipin 2 (PLIN2) and peroxisome proliferator-activated receptor gamma (PPARγ) in vitro and in vivo, respectively. Immunocytochemistry revealed that Rab18 colocalized with PLIN2 and PPARγ in AML-12 cells. Rab18 expression was elevated in vitro and in vivo in the NAFLD mouse model. Rab18 regulates PLIN2 and PPARγ expression to exaggerate liver injury and lipid accumulation in patients with NAFLD. Thus, Rab18 may be a crucial protein in this disease and a potential therapeutic target.

Serum Metabolomics Uncovers the Mechanisms of Inulin in Preventing Non-Alcoholic Fatty Liver Disease.

Inulin may be a promising therapeutic molecule for treating non-alcoholic fatty liver disease (NAFLD). However, the underlying mechanisms of its therapeutic activity remain unclear. To address this issue, a high-fat-diet-induced NAFLD mouse model was developed and treated with inulin. The NAFLD phenotype was evaluated via histopathological analysis and biochemical parameters, including serum levels of alanine aminotransferase, aspartate aminotransferase, liver triglycerides, etc. A serum metabolomics study was conducted using ultra-performance liquid chromatography coupled with tandem mass spectrometry. The results revealed that inulin mitigated NAFLD symptoms such as histopathological changes and liver cholesterol levels. Through the serum metabolomics study, 347 differential metabolites were identified between the model and control groups, and 139 differential metabolites were identified between the inulin and model groups. Additionally, 48 differential metabolites (such as phosphatidylserine, dihomo-γ-linolenic acid, L-carnitine, and 13-HODE) were identified as candidate targets of inulin and subjected to pathway enrichment analysis. The results revealed that these 48 differential metabolites were enriched in several metabolic pathways such as fatty acid biosynthesis and cardiolipin biosynthesis. Taken together, our results suggest that inulin might attenuate NAFLD partially by modulating 48 differential metabolites and their correlated metabolic pathways, constituting information that might help us find novel therapies for NAFLD.

Oleuropein mitigates non-alcoholic fatty liver disease (NAFLD) and modulates liver metabolites in high-fat diet-induced obese mice via activating PPARα.

This study aimed to elucidate the mechanism of oleuropein (OLE) ameliorates non-alcoholic fatty liver disease (NAFLD) and its underlying mechanisms. Male C57BL/6J mice were fed either a low-fat diet (LFD), a high-fat diet (HFD), or a HFD supplemented with 0.03% (w/w) OLE for 16 weeks. OLE supplementation decreased body weight and liver weight, improved serum lipid profiles, and ameliorated HFD-induced hepatic dysfunction. Liver metabolomics analysis revealed that OLE increased the levels of nicotinamide, tauroursodeoxycholic acid, taurine, and docosahexaenoic acid, which were beneficial for lipid homeostasis and inflammation regulation. OLE exerted its protective effects by activating peroxisome proliferator-activated receptor alpha (PPARα), a key transcription factor that regulates fibroblast growth factor 21 (FGF21) expression and modulates lipid oxidation, lipogenesis and inflammation pathways. Importantly, OLE supplementation did not significantly affect body weight or liver weight in PPARα knockout (PPARα KO) mice, indicating that PPARα is essential for OLE-mediated NAFLD prevention. Our results suggest that OLE alleviates NAFLD in mice by activating PPARα and modulating liver metabolites. © 2024 Society of Chemical Industry.

Increase in bile acids after sleeve gastrectomy improves metabolism by activating GPBAR1 to increase cAMP in mice with nonalcoholic fatty liver disease.

Bile acids (BAs) concentration can affect metabolic improvement caused by bariatric surgery and BA concentrations increase in patients after sleeve gastrectomy (SG). Here, how BAs after SG affect metabolism in nonalcoholic fatty liver disease (NAFLD) was studied. Mice were given high-fat diet (HFD) to induce NAFLD and received SG surgery. Hepatic and fecal BA concentrations in mice were detected by liquid chromatography-tandem mass spectrometry method. BA-related genes were detected by quantitative real-time polymerase chain reaction. G protein BA receptor 1 (GPBAR1) expression was identified using western blot analysis. NAFLD mice after SG received GPBAR1 inhibitor Triamterene. The weight of mice and mice liver was detected. Mouse liver tissue was observed by hematoxylin-eosin and Oil Red O staining. Triglyceride (TG), nonesterified fatty acid (NEFA), and cyclic adenosine monophosphate (cAMP) levels in mouse liver tissue were analyzed by metabolic assay and enzyme-linked immune sorbent assay. SG boosted increase in hepatic total/conjugated BAs and related genes and GPBAR1 expression, and attenuated increase in fecal total BAs/muricholic acid in HFD-induced mice and increased fecal taurine-BAs in HFD-induced mice. Triamterene (72 mg/kg) reversed the inhibitory role of SG in HFD-induced increase of body weight, lipid accumulation, inflammatory cell infiltration, and increase of hepatic weight and TG/NEFA content, and counteracted the positive role of SG in HFD-induced increase of hepatic cAMP concentration in mice. BAs improve metabolism via activating GPBAR1 to increase cAMP in NAFLD mice after SG.

Ebselen improves lipid metabolism by activating PI3K/Akt and inhibiting TLR4/JNK signaling pathway to alleviate nonalcoholic fatty liver

Nonalcoholic fatty liver disease (NAFLD), a metabolic disease associated with obesity and type 2 diabetes. Due to its complex pathogenesis, there are still limitations in the knowledge of the disease. To date, no drug has been approved to treat NAFLD. This study aims to explore the role and mechanism of Ebselen (EbSe) in NAFLD. A high-fat diet-induced mouse model of NAFLD was employed to investigate EbSe function in NAFLD mice by EbSe gavage and to regularly monitor the mouse body weight. HE and oil red O staining were performed, respectively, to detect the pathological damage and lipid accumulation in mouse liver tissues. The biochemical and ELISA kits were employed to measure the levels of ALT, AST, TG, TC, LDL-C, HDL-C and pro-inflammatory cytokines within mouse serum or liver tissue. The expression of key proteins of PPARα, fatty acid β oxidation-related protein, PI3K/Akt and TLR4/JNK signaling pathway was detected by western blot. EbSe significantly downregulated body weight, liver weight and liver lipid accumulation in NAFLD mice and downregulated ALT, AST, TG, TC, LDL-C and increased HDL-C serum levels. EbSe upregulated the expression levels of PPARα and fatty acid β oxidation-associated proteins CPT1α, ACOX1, UCP2 and PGC1α. EbSe promoted Akt and PI3K phosphorylation, and inhibited TLR4 expression and JNK phosphorylation. EbSe can upregulate PPARα to promote fatty acid β-oxidation and improve hepatic lipid metabolism. Meanwhile, EbSe also activated PI3K/Akt and inhibited TLR4/JNK signaling pathway. EbSe is predicted to be an effective therapeutic drug for treating NAFLD.

Lipid Nanoparticle-Mediated Delivery of CRISPR-Cas9 Against Rubicon Ameliorates NAFLD by Modulating CD36 Along with Glycerophospholipid Metabolism.

Non-alcoholic fatty liver disease (NAFLD) is a prominent cause of various chronic metabolic hepatic diseases with limited therapeutics. Rubicon, an essential regulator in lysosomal degradation, is reported to exacerbate hepatic steatosis in NAFLD mice and patients, indicating its probability of being a therapeutic target for NAFLD treatment. In this study, the therapeutic potential of Rubicon blockage is investigated. Lipid nanoparticles carrying Rubicon-specific CRISPR-Cas9 components exhibited liver accumulation, cell internalization, and Rubicon knockdown. A single administration of the nanoparticles results in attenuated lipid deposition and hepatic steatosis, with lower circulating lipid levels and decreased adipocyte size in NAFLD mice. Furthermore, the increase of phosphatidylcholine and phosphatidylethanolamine levels can be observed in the NAFLD mice livers after Rubicon silencing, along with regulatory effects on metabolism-related genes such as CD36, Gpcpd1, Chka, and Lpin2. The results indicate that knockdown of Rubicon improves glycerophospholipid metabolism and thereby ameliorates the NAFLD progression, which provides a potential strategy for NAFLD therapy via the restoration of Rubicon.

Chronic pharmacologic manipulation of dopamine transmission ameliorates metabolic disturbance in Trappc9-linked brain developmental syndrome.

Loss-of-function mutations of the gene encoding the trafficking protein particle complex subunit 9 (Trappc9) cause autosomal recessive intellectual disability and obesity by unknown mechanisms. Genome-wide analysis links Trappc9 to nonalcoholic fatty liver disease (NAFLD). Trappc9-deficient mice have been shown to appear overweight shortly after weaning. Here, we analyzed serum biochemistry and histology of adipose and liver tissues to determine the incidence of obesity and NAFLD in Trappc9-deficient mice and combined transcriptomic and proteomic analyses, pharmacological studies, and biochemical and histological examinations of postmortem mouse brains to unveil mechanisms involved. We found that Trappc9-deficient mice presented with systemic glucose homeostatic disturbance, obesity, and NAFLD, which were relieved upon chronic treatment combining dopamine receptor D2 (DRD2) agonist quinpirole and DRD1 antagonist SCH23390. Blood glucose homeostasis in Trappc9-deficient mice was restored upon administering quinpirole alone. RNA-sequencing analysis of DRD2-containing neurons and proteomic study of brain synaptosomes revealed signs of impaired neurotransmitter secretion in Trappc9-deficient mice. Biochemical and histological studies of mouse brains showed that Trappc9-deficient mice synthesized dopamine normally, but their dopamine-secreting neurons had a lower abundance of structures for releasing dopamine in the striatum. Our study suggests that Trappc9 loss of function causes obesity and NAFLD by constraining dopamine synapse formation.