L-Lysine Attenuates Hepatic Steatosis in Senescence-Accelerated Mouse Prone 8 Mice

Ginseng polysaccharide components attenuate obesity and liver lipid accumulation by regulating fecal microbiota and hepatic lysine degradation

The increasing incidence of obesity has led to widespread attention in the exploration of natural ingredients. Ginseng polysaccharides (PGP), the main components from Panax ginseng, have been reported potential effect to attenuate obesity and regulate lipid metabolism. In this study, we found that PGP inhibited the high-fat diet (HFD)-induced weight gain, fat ratio and fat tissue weight after 8-week administration. Serum and liver lipid analysis showed that PGP decreased the levels of triglyceride and total cholesterol, which was mediated by the inhibition of key genes for fatty acid and cholesterol metabolisms. Metabolomics studies showed that the inhibitory effect of PGP on liver lipid accumulation was significantly correlated with its regulation of citric acid cycle and lysine degradation. PGP regulated the expression of genes related to lysine degradation in both liver tissue and hepatocytes. In addition, PGP reshaped the composition of fecal microbiota at the genus and species levels in obese mice. Spearman's correlation analysis demonstrated that Staphylococcus sciuri, Staphylococcus lentus, and Pseudoflavonifractor sp. An85 may be the potential targets that PGP maintains the abundance of l-lysine against obesity. It concluded that PGP can attenuate obesity and liver lipid accumulation by regulating fecal microbiota and hepatic lysine degradation.

The role of amino acid metabolism in autoimmune hepatitis

Autoimmune hepatitis (AIH) is an inflammatory chronic liver disease with persistent and recurrent immune-mediated liver injury. The exact cause of AIH is still not fully understood, but it is believed to be primarily due to an abnormal activation of the immune system, leading to autoimmune injury caused by the breakdown of autoimmune tolerance. Although the pathogenesis of AIH remains unclear, recent studies have shown that abnormalities in amino acid metabolism play significant roles in its development. These abnormalities in amino acid metabolism can lead to remodeling of metabolic processes, activation of signaling pathways, and immune responses, which may present new opportunities for clinical intervention in AIH. In this paper, we first briefly outline the recent progress of clinically relevant research on AIH, focusing on the role of specific amino acid metabolism (including glutamine, cysteine, tryptophan, branched-chain amino acids, etc.) and their associated metabolites, as well as related pathways, in the development of AIH. Furthermore, we discuss the scientific issues that remain to be resolved regarding amino acid metabolism, AIH development and related clinical interventions, with the aim of contributing to the future development of amino acid metabolism-based as a new target for the clinical diagnosis and treatment of AIH.

Molecular mechanism and therapeutic significance of essential amino acids in metabolically associated fatty liver disease

Non-alcoholic fatty liver disease (NAFLD), also known as metabolically associated fatty liver disease (MAFLD), is a systemic metabolic disease characterized by lipid accumulation in the liver, lipid toxicity, insulin resistance, intestinal dysbiosis, and inflammation that can progress from simple steatosis to nonalcoholic steatohepatitis (NASH) and even cirrhosis or cancer. It is the most prevalent illness threatening world health. Currently, there are almost no approved drug interventions for MAFLD, mainly dietary changes and exercise to control weight and regulate metabolic disorders. Meanwhile, the metabolic pathway involved in amino acid metabolism also influences the onset and development of MAFLD in the body, and most amino acid metabolism takes place in the liver. Essential amino acids are those amino acids that must be supplemented from outside the diet and that cannot be synthesized in the body or cannot be synthesized at a rate sufficient to meet the body's needs, including leucine, isoleucine, valine (collectively known as branched-chain amino acids), tryptophan, phenylalanine (which are aromatic amino acids), histidine, methionine, threonine and lysine. The metabolic balance of the body is closely linked to these essential amino acids, and essential amino acids are closely linked to the pathophysiological process of MAFLD. In this paper, we will focus on the metabolism of essential amino acids in the body and further explore the therapeutic strategies for MAFLD based on the studies conducted in recent years.

A novel network pharmacology strategy to decode mechanism of Wuling Powder in treating liver cirrhosis

BACKGROUND

Liver cirrhosis is a chronic liver disease with hepatocyte necrosis and lesion. As one of the TCM formulas Wuling Powder (WLP) is widely used in the treatment of liver cirrhosis. However, it's key functional components and action mechanism still remain unclear. We attempted to explore the Key Group of Effective Components (KGEC) of WLP in the treatment of Liver cirrhosis through integrative pharmacology combined with experiments.

METHODS

The components and potential target genes of WLP were extracted from published databases. A novel node importance calculation model considering both node control force and node bridging force is designed to construct the Function Response Space (FRS) and obtain key effector proteins. The genetic knapsack algorithm was employed to select KGEC. The effectiveness and reliability of KGEC were evaluated at the functional level by using gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Finally, the effectiveness and potential mechanism of KGEC were confirmed by CCK-8, qPCR and Western blot.

RESULTS

940 effective proteins were obtained in FRS. KEGG pathways and GO terms enrichments analysis suggested that effective proteins well reflect liver cirrhosis characteristics at the functional level. 29 components of WLP were defined as KGEC, which covered 100% of the targets of the effective proteins. Additionally, the pathways enriched for the KGEC targets accounted for 83.33% of the shared genes between the targets and the pathogenic genes enrichment pathways. Three components scopoletin, caryophyllene oxide, and hydroxyzinamic acid from KGEC were selected for in vivo verification. The qPCR results demonstrated that all three components significantly reduced the mRNA levels of COL1A1 in TGF-β1-induced liver cirrhosis model. Furthermore, the Western blot assay indicated that these components acted synergistically to target the NF-κB, AMPK/p38, cAMP, and PI3K/AKT pathways, thus inhibiting the progression of liver cirrhosis.

CONCLUSION

In summary, we have developed a new model that reveals the key components and potential mechanisms of WLP for the treatment of liver cirrhosis. This model provides a reference for the secondary development of WLP and offers a methodological strategy for studying TCM formulas.

L-lysine supplementation attenuates experimental autoimmune hepatitis in a chronic murine model

The incidence of autoimmune hepatitis (AIH) has increased significantly worldwide. The present study aims to explore the protective effect of L-lysine supplementation against AIH and to investigate its potential underlying mechanisms. A chronic experimental AIH mouse model was established by repeated tail vein injection of human cytochrome P450 2D6 (CYP2D6) plasmid. Starting from day 14 of the modeling, mice in the CYP2D6-AIH +L-lysine group were given 200 µl of purified water containing 10 mg/kg L-lysine by gavage until day27, once a day, and mice in the healthy control group and model group were given an equal volume of purified water by gavage. Our results showed that L-lysine supplementation partially reversed the liver injury mediated by CYP2D6 overexpression. These effects were consistent with the restraining impacts of L-lysine supplementation on decreasing pro-inflammatory cytokines expression level and CD4+ and CD8+ T lymphocytes infiltration, as well as curbing hepatic oxidative stress. Furthermore, L-lysine supplement relieved liver fibrosis in the context of AIH. In conclusion, L-lysine supplementation attenuates CYP2D6-induced immune liver injury in mice, which may serve as a novel nutrition support approach for AIH.

Integrated Analysis of Gut Microbiome and Liver Metabolome to Evaluate the Effects of Fecal Microbiota Transplantation on Lipopolysaccharide/D-galactosamine-Induced Acute Liver Injury in Mice

Acute liver failure (ALF) refers to the occurrence of massive hepatocyte necrosis in a short time, with multiple complications, including inflammatory response, hepatic encephalopathy, and multiple organ failure. Additionally, effective therapies for ALF are lacking. There exists a relationship between the human intestinal microbiota and liver, so intestinal microbiota modulation may be a strategy for therapy of hepatic diseases. In previous studies, fecal microbiota transplantation (FMT) from fit donors has been used to modulate intestinal microbiota widely. Here, we established a mouse model of lipopolysaccharide (LPS)/D-galactosamine (D-gal) induced ALF to explore the preventive and therapeutic effects of FMT, and its mechanism of action. We found that FMT decreased hepatic aminotransferase activity and serum total bilirubin levels, and decreased hepatic pro-inflammatory cytokines in LPS/D-gal challenged mice (p < 0.05). Moreover, FMT gavage ameliorated LPS/D-gal induced liver apoptosis and markedly reduced cleaved caspase-3 levels, and improved histopathological features of the liver. FMT gavage also restored LPS/D-gal-evoked gut microbiota dysbiosis by modifying the colonic microbial composition, improving the abundance of unclassified_o_Bacteroidales (p < 0.001), norank_f_Muribaculaceae (p < 0.001), and Prevotellaceae_UCG-001 (p < 0.001), while reducing that of Lactobacillus (p < 0.05) and unclassified_f_Lachnospiraceae (p < 0.05). Metabolomics analysis revealed that FMT significantly altered LPS/D-gal induced disordered liver metabolites. Pearson's correlation revealed strong correlations between microbiota composition and liver metabolites. Our findings suggest that FMT ameliorate ALF by modulating gut microbiota and liver metabolism, and can used as a potential preventive and therapeutic strategy for ALF.

A novel chicken model of fatty liver disease induced by high cholesterol and low choline diets

Fatty liver diseases, common metabolic diseases in chickens, can lead to a decrease in egg production and sudden death of chickens. To solve problems caused by the diseases, reliable chicken models of fatty liver disease are required. To generate chicken models of fatty liver, 7-week-old ISA female chickens were fed with a control diet (17% protein, 5.3% fat, and 1,300 mg/kg choline), a low protein and high fat diet (LPHF, 13% protein, 9.1% fat, and 1,300 mg/kg choline), a high cholesterol with low choline diet (CLC, 17% protein, 7.6% fat with additional 2% cholesterol, and 800 mg/kg choline), a low protein, high fat, high cholesterol, and low choline diet (LPHFCLC, 13% protein, 12.6% fat with additional 2% cholesterol, and 800 mg/kg choline) for 4 wk. Our data showed that the CLC and LPHFCLC diets induced hyperlipidemia. Histological examination and the content of hepatic lipids indicated that the CLC and LPHFCLC diets induced hepatic steatosis. Plasma dipeptidyl peptidase 4, a biomarker of fatty liver diseases in laying hens, increased in chickens fed with the CLC or LPHFCLC diets. Hepatic ballooning and immune infiltration were observed in these livers accompanied by elevated interleukin 1 beta and lipopolysaccharide induced tumor necrosis factor mRNAs suggesting that the CLC and LPHFCLC diets also caused steatohepatitis in these livers. These diets also induced hepatic steatosis in Plymouth Rock chickens. Thus, the CLC and LPHFCLC diets can be used to generate models for fatty liver diseases in different strains of chickens. In ISA chickens fed with the CLC diet, peroxisome proliferator-activated receptor γ, sterol regulatory element binding transcription factor 1, and fatty acid synthase mRNAs increased in the livers, suggesting that lipogenesis was enhanced by the CLC treatment. Our data show that treatment with CLC or LPHFCLC for 4 wk induces fatty liver disease in chickens. These diets can be utilized to rapidly generate chicken models for fatty liver research.