Arrb2 causes hepatic lipid metabolism disorder via AMPK pathway based on metabolomics in alcoholic fatty liver

Myeloid beta-arrestin 2 depletion attenuates metabolic dysfunction-associated steatohepatitis via the metabolic reprogramming of macrophages

Macrophage-mediated inflammation has been implicated in the pathogenesis of metabolic dysfunction-associated steatohepatitis (MASH); however, the immunometabolic program underlying the regulation of macrophage activation remains unclear. Beta-arrestin 2, a multifunctional adaptor protein, is highly expressed in bone marrow tissues and macrophages and is involved in metabolism disorders. Here, we observed that β-arrestin 2 expression was significantly increased in the liver macrophages and circulating monocytes of patients with MASH compared with healthy controls and positively correlated with the severity of metabolic dysfunction-associated steatotic liver disease (MASLD). Global or myeloid Arrb2 deficiency prevented the development of MASH in mice. Further study showed that β-arrestin 2 acted as an adaptor protein and promoted ubiquitination of immune responsive gene 1 (IRG1) to prevent increased itaconate production in macrophages, which resulted in enhanced succinate dehydrogenase activity, thereby promoting the release of mitochondrial reactive oxygen species and M1 polarization. Myeloid β-arrestin 2 depletion may be a potential approach for MASH.

Insight into the regulatory mechanism of β-arrestin2 and its emerging role in diseases

β-arrestin2, a member of the arrestin family, mediates the desensitization and internalization of most G protein-coupled receptors (GPCRs) and functions as a scaffold protein in signalling pathways. Previous studies have demonstrated that β-arrestin2 expression is dysregulated in malignant tumours, fibrotic diseases, cardiovascular diseases and metabolic diseases, suggesting its pathological roles. Transcription and post-transcriptional modifications can affect the expression of β-arrestin2. Furthermore, post-translational modifications, such as phosphorylation, ubiquitination, SUMOylation and S-nitrosylation affect the cellular localization of β-arrestin2 and its interaction with downstream signalling molecules, which further regulate the activity of β-arrestin2. This review summarizes the structure and function of β-arrestin2 and reveals the mechanisms involved in the regulation of β-arrestin2 at multiple levels. Additionally, recent studies on the role of β-arrestin2 in some major diseases and its therapeutic prospects have been discussed to provide a reference for the development of drugs targeting β-arrestin2.

The Flavonoid Glycoside from Abrus cantoniensis Hance Alleviates Alcoholic Liver Injury by Inhibiting Ferroptosis in an AMPK-Dependent Manner

Abrus cantoniensis Hance is a vegetative food and can be used as a folk beverage or soup to clear liver toxins and prevent liver damage. However, the components and effects of A. cantoniensis Hance in alcohol-induced liver injury were unknown. This study aimed to obtain abundant phytochemicals from A. cantoniensis Hance and identify the potency of the isolates in preventing alcohol-induced liver injury. Alcohol-stimulated AML12 cells and Lieber-DeCarli diet-fed mice were used to establish in vitro and in vivo models, respectively. Our findings indicated that flavonoid glycosides, especially AH-15, could significantly alleviate alcohol-induced liver injury by inhibiting oxidative stress. Furthermore, we demonstrated that AH-15 inhibited ferroptosis induced by lipid peroxidation. Mechanically, we found that AH-15 regulated nuclear factor erythroid 2-related factor 2 (NRF2) expression via activation of AMP-activated protein kinase (AMPK) signaling. These results indicate that A. cantoniensis Hance is a great potential functional food for alleviating alcohol-induced liver injury.

Dihydroartemisinin ameliorates the liver steatosis in metabolic associated fatty liver disease mice by attenuating the inflammation and oxidative stress and promoting autophagy

PURPOSE

To explore the effect and potential mechanism of dihydroartemisinin (DHA) on metabolism-related fatty liver disease.

METHODS

A metabolic associated fatty liver disease (MAFLD) mice model was induced with continuous supplies of high-fat diet. DHA was intraperitoneally injected into mice. The weight of mice was monitored. The concentrations of total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) in serum were detected by an automatic biochemical analyzer. The liver tissues were stained by hematoxylin and eosin and oil red O. The level of inflammation, oxidative stress, and autophagy was assessed by reverse transcription polymerase chain reaction, biochemical examination, Western blot and transmission electron microscope assays.

RESULTS

DHA treatment reduced theMAFLD-enhanced the level of weight gain, the concentrations of TC, TG, LDL and malonaldehyde, while increasedthe MAFLD-decreased the concentrations of HDL and superoxide dismutase. DHA ameliorated the MAFLD-aggravated pathological changes and the number of lipid droplets. Low dose of DHA declined the MAFLD-induced the enhancement of the expression of inflammatory factor. DHA treatment increased the MAFLD-enhanced the level of autophagy related protein, while decreased the MAFLD-reduced the protein level of p62. The increased level of autophagy was confirmed by transmission electron microscope.

CONCLUSIONS

DHA can improve liver steatosis in MAFLD mice by inhibiting inflammation and oxidative stress and promoting autophagy.

Berberine Ameliorates Abnormal Lipid Metabolism via the Adenosine Monophosphate-Activated Protein Kinase/Sirtuin 1 Pathway in Alcohol-Related Liver Disease

Alcoholic fatty liver disease (AFLD) is an early stage of alcohol-related liver disease characterized by abnormal lipid metabolism in hepatocytes. To date, to our knowledge, there have been no effective strategies for preventing or treating alcohol-related liver disease besides alcohol abstinence. Berberine (BBR) is the main bioactive ingredient extracted from traditional Chinese medicines, such as Coptis and Scutellaria, which protect liver function and relieve liver steatosis. However, the potential role of BBR in AFLD remains unclear. Therefore, this study investigated the protective effects of BBR against Gao-binge model-induced AFLD in 6- to 8-week-old C57BL/6J male mice in vivo and ethyl alcohol (EtOH)-induced alpha mouse liver 12 (AML-12) cells in vitro. The results showed that BBR (200 mg/kg) attenuated alcoholic liver injury and suppressed lipid accumulation and metabolism disorders in vivo. Consistently, BBR effectively inhibited the expression of sterol regulatory element-binding transcription factor 1C, sterol regulatory element-binding transcription factor 2, fatty acid synthase, and 3-hydroxy-3-methylglutaryl-CoenzymeA reductase in EtOH-stimulated AML-12 cells in vitro and promoted the expression of sirtuin 1 (SIRT1) in EtOH-fed mice and EtOH-treated AML-12 cells. Furthermore, SIRT1 silencing attenuated the hepatic steatosis alleviation potential of BBR treatment. Mechanistically, molecular docking revealed the binding effect of BBR and adenosine monophosphate-activated protein kinase (AMPK). The results of further studies showed that a decrease in AMPK activity was accompanied by a significant inhibition of SIRT1 expression. SIRT1 silencing attenuated the protective effect of BBR, whereas the inhibition of its expression had no apparent effect on AMPK phosphorylation, suggesting that SIRT1 acts downstream of AMPK in AFLD. Collectively, BBR ameliorated abnormal lipid metabolism and alleviated EtOH-induced liver injury via the AMPK/SIRT1 pathway in AFLD mice.

Antioxidant effects of Se-glutathione peroxidase in alcoholic liver disease

Oxidative damage induced by ethanol and its metabolites is one of the factors that fuels the development of alcoholic liver disease (ALD). Selenium (Se) is an effective cofactor for glutathione peroxidase (GPx), and has antioxidant effects that improve ALD. In patients with ALD, ethanol-induced oxidative damage inhibits the synthesis of related Se-containing proteins such as: selenoprotein P (Sepp1), albumin (ALB), and GPx in the liver, thus decreasing the overall Se level in patients. Both Se deficiency and excess can affect the expression of GPx, resulting in damage to the antioxidant defense system. This damage enhances oxidative stress by increasing the levels of reactive oxygen species (ROS) in the body, which aggravates the inflammatory response, lipid metabolism disorder, and lipid peroxidation and worsens ALD symptoms. A cascade of oxidative damages caused by ALD will deplete selenium deposition in the body, stimulate the expression of Gpx1, Sepp1, and Gpx4, and thus mobilize systemic selenoproteins, which can restore GPx activity in the hepatocytes of ALD patients, reduce the levels of reactive oxygen species and alleviate oxidative stress, the inflammatory response, lipid metabolism disorder, and lipid peroxidation, thus helping to mitigate ALD. This review provides a reference for future ALD studies that evaluate the regulation of Se levels and contributes to studies on the potential pathological mechanisms of Se imbalance in ALD.

FNDC3B protects steatosis and ferroptosis via the AMPK pathway in alcoholic fatty liver disease

BACKGROUND

Alcoholic liver disease (ALD) is a leading cause of chronic liver disease worldwide with limited therapeutic options. The role of fibronectin type III domain-containing protein 3B (FNDC3B), an important regulator of metabolism, in ALD, and the underlying mechanism as well as its potential implication in ALD therapeutic strategies remain unknown.

METHODS

Hepatocyte-specific FNDC3B knockdown or control C57BL/6 N mice received a Lieber-DeCarli diet for four weeks, followed by oral gavage (chronic-binge). Primary mouse hepatocytes and cell lines were used for in vitro studies. Liver injury, hepatic steatosis, and lipid peroxidation were assessed.

RESULTS

In cultured cells and mouse livers, alcohol exposure increased FNDC3B expression. Hepatocyte-specific FNDC3B deletion aggravated alcohol-induced liver steatosis via AMP-activated protein kinase (AMPK) inhibition. In vitro, FNDC3B expression was negatively regulated by miR-192-5p. Furthermore, FNDC3B deletion significantly exacerbated ethanol-mediated lipid peroxidation. The RNA sequence assay revealed a connection between FNDC3B and ferroptosis, which was verified by the administration of the ferroptosis inhibitor ferrostatin-1 (Fer-1). Additionally, FNDC3B inhibition-mediated AMPK inactivation downregulated transferrin expression, which was associated with marked iron overload and ferroptosis.

CONCLUSIONS

This study elucidated the critical role of FNDC3B in preventing hepatic steatosis and ferroptosis in response to chronic alcohol consumption. Our findings indicate that FNDC3B is a potential therapeutic target for ALD.

Isoliquiritigenin-mediated miR-23a-3p inhibition activates PGC-1α to alleviate alcoholic liver injury

BACKGROUND

Alcoholic liver disease (ALD), one of the most prevalent forms of liver disease, has received wide attention worldwide. However, limited efficient and appropriate therapeutic agents were responded to ALD. Isoliquiritigenin (ISL), a flavonoid isolated from liquorice, possesses multiple pharmacological activities.

PURPOSE

The current study investigated the hepatoprotective effect of ISL against ALD and further elucidate the involvement of miR-23a-3p/peroxisome proliferative activated receptor-γ coactivator 1 alpha (PGC-1α) in vivo and in vitro experiments.

STUDY DESIGN AND METHODS

In the study, H&E and Oil Red O staining were employed to detect liver histopathological changes and the accumulation of lipid droplets. Quantitative real-time PCR, bioinformatics, luciferase assay, immunofluorescence staining, reactive oxygen species (ROS), Western blot, and siRNA were used to further explore the mechanism of ISL protection.

RESULTS

ISL significantly reduced the liver-to-body weight ratios and biochemical index. The staining results showed that ISL remarkedly ameliorated the histopathological changes in the liver. Furthermore, ISL promoted fatty acid metabolism via induction in the expression of PGC-1α-target genes PPARα, CPT1α, and ACADs, and inhibited the ROS, TNF-α, IL-1β, and IL-6 expression. Bioinformatics and Luciferase assay analysis confirmed that miR-23a-3p might bind to PGC-1α mRNA in ALD. Significantly, the expression of miR-23a-3p was increased in the ALD, which was significantly decreased by ISL. In addition, the miR-23a-3p inhibitor also promoted lipid metabolism in ALD via PGC-1α activation.

CONCLUSIONS

We first demonstrated that ISL could alleviate ALD, and further verified that ISL exerted protective effects through modulating miR-23a-3p/PGC-1α-mediated lipid metabolism in vivo and in vitro.

Changes and Correlations of the Intestinal Flora and Liver Metabolite Profiles in Mice With Gallstones

There is increasing appreciation for the roles of the gut-liver axis in liver and gall diseases. Specific gut microbes are associated with susceptibility to gallstone diseases, while the relationship between intestinal flora and liver metabolism in the formation of gallstones remains unclear. In this study, an experimental group of model mice was given a lithogenic diet, and a control group was given a normal diet. Both groups were fed for 8 weeks. Integrating 16S rRNA gene sequencing and non-targeted metabolomics to explore the impact of the lithogenic diet on intestinal flora and liver metabolism, Spearman correlation analysis reveals the network of relationships between the intestine and liver. Our findings showed that the gut microbiome and liver metabolome compositions of the test group were significantly changed compared with those of the normal group. Through our research, biomarkers of gallstones were identified at the phylum (5), class (5), order (5), family (7), and genus levels. We predicted the function of the differential flora. We analyzed the liver metabolism of mice with gallstones paired with their flora, and the results showed that there were 138 different metabolites between the two groups. The metabolic pathways enriched by these differential metabolites are highly consistent with the functions of the disordered flora. We focused on an analysis of the relationship between deoxycholic acid, asymmetric dimethylarginine, glucosamine, tauroursodeoxycholic acid, and the disordered flora. This provides a basis for the establishment of the intestine-liver axis in gallstone disease. This research provides a theoretical basis for the research and development of probiotics and prebiotics.