Dataset Information

Bile acid-receptor TGR5 deficiency worsens liver injury in alcohol-fed mice by inducing intestinal microbiota dysbiosis.

ABSTRACT:

Background & aims

Bile-acid metabolism and the intestinal microbiota are impaired in alcohol-related liver disease. Activation of the bile-acid receptor TGR5 (or GPBAR1) controls both biliary homeostasis and inflammatory processes. We examined the role of TGR5 in alcohol-induced liver injury in mice.

Methods

We used TGR5-deficient (TGR5-KO) and wild-type (WT) female mice, fed alcohol or not, to study the involvement of liver macrophages, the intestinal microbiota (16S sequencing), and bile-acid profiles (high-performance liquid chromatography coupled to tandem mass spectrometry). Hepatic triglyceride accumulation and inflammatory processes were assessed in parallel.

Results

TGR5 deficiency worsened liver injury, as shown by greater steatosis and inflammation than in WT mice. Isolation of liver macrophages from WT and TGR5-KO alcohol-fed mice showed that TGR5 deficiency did not increase the pro-inflammatory phenotype of liver macrophages but increased their recruitment to the liver. TGR5 deficiency induced dysbiosis, independently of alcohol intake, and transplantation of the TGR5-KO intestinal microbiota to WT mice was sufficient to worsen alcohol-induced liver inflammation. Secondary bile-acid levels were markedly lower in alcohol-fed TGR5-KO than normally fed WT and TGR5-KO mice. Consistent with these results, predictive analysis showed the abundance of bacterial genes involved in bile-acid transformation to be lower in alcohol-fed TGR5-KO than WT mice. This altered bile-acid profile may explain, in particular, why bile-acid synthesis was not repressed and inflammatory processes were exacerbated.

Conclusions

A lack of TGR5 was associated with worsening of alcohol-induced liver injury, a phenotype mainly related to intestinal microbiota dysbiosis and an altered bile-acid profile, following the consumption of alcohol.

Lay summary

Excessive chronic alcohol intake can induce liver disease. Bile acids are molecules produced by the liver and can modulate disease severity. We addressed the specific role of TGR5, a bile-acid receptor. We found that TGR5 deficiency worsened alcohol-induced liver injury and induced both intestinal microbiota dysbiosis and bile-acid pool remodelling. Our data suggest that both the intestinal microbiota and TGR5 may be targeted in the context of human alcohol-induced liver injury.

SUBMITTER: Spatz M

PROVIDER: S-EPMC7903352 | biostudies-literature | 2021 Apr

REPOSITORIES: biostudies-literature

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Publications

Bile acid-receptor TGR5 deficiency worsens liver injury in alcohol-fed mice by inducing intestinal microbiota dysbiosis.

Spatz Madeleine M Ciocan Dragos D Merlen Gregory G Rainteau Dominique D Humbert Lydie L Gomes-Rochette Neuza N Hugot Cindy C Trainel Nicolas N Mercier-Nomé Françoise F Domenichini Séverine S Puchois Virginie V Wrzosek Laura L Ferrere Gladys G Tordjmann Thierry T Perlemuter Gabriel G Cassard Anne-Marie AM

JHEP reports : innovation in hepatology 20210119 2

<h4>Background & aims</h4>Bile-acid metabolism and the intestinal microbiota are impaired in alcohol-related liver disease. Activation of the bile-acid receptor TGR5 (or GPBAR1) controls both biliary homeostasis and inflammatory processes. We examined the role of TGR5 in alcohol-induced liver injury in mice.<h4>Methods</h4>We used TGR5-deficient (TGR5-KO) and wild-type (WT) female mice, fed alcohol or not, to study the involvement of liver macrophages, the intestinal microbiota (16S sequencing), ...[more]

PMID: 33665587

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Project description:Takeda G protein-coupled receptor 5 (TGR5) agonists induce systemic release of glucagon-like peptides (GLPs) from intestinal L cells, a potentially therapeutic action against metabolic diseases such as nonalcoholic steatohepatitis (NASH), nonalcoholic fatty liver disease (NAFLD), and Type 2 diabetes. Historically, TGR5 agonist use has been hindered by side effects, including inhibition of gallbladder emptying. Here, we characterize RDX8940, a novel, orally administered TGR5 agonist designed to have minimal systemic effects and investigate its activity in mice fed a Western diet, a model of NAFLD and mild insulin resistance. Agonist activity, binding selectivity, toxicity, solubility, and permeability of RDX8940 were characterized in standard in vitro models. RDX8940 pharmacokinetics and effects on GLP secretion, insulin sensitivity, and liver steatosis were assessed in C57BL/6 mice fed normal or Western diet chow and given single or repeated doses of RDX8940 or vehicle, with or without dipeptidyl peptidase-4 (DPP4) inhibitors. Gallbladder effects were assessed in CD-1 mice fed normal chow and given RDX8940 or a systemic TGR5 agonist or vehicle. Our results showed that RDX8940 is minimally systemic, potent, and selective, and induces incretin (GLP-1, GLP-2, and peptide YY) secretion. RDX8940-induced increases in plasma active GLP-1 (aGLP-1) levels were enhanced by repeated dosing and by coadministration of DPP4 inhibitors. RDX8940 increased hepatic exposure to aGLP-1 without requiring coadministration of a DPP4 inhibitor. In mice fed a Western diet, RDX8940 improved liver steatosis and insulin sensitivity. Unlike systemic TGR5 agonists, RDX8940 did not inhibit gallbladder emptying. These results indicate that RDX8940 may have therapeutic potential in patients with NAFLD/NASH. NEW & NOTEWORTHY Takeda G protein-coupled receptor 5 (TGR5) agonists have potential as a treatment for nonalcoholic steatohepatitis and nonalcoholic fatty liver disease (NAFLD) but have until now been associated with undesirable side effects associated with systemic TGR5 agonism, including blockade of gallbladder emptying. We demonstrate that RDX8940, a potent, selective, minimally systemic oral TGR5 agonist, improves liver steatosis and insulin sensitivity in a mouse model of NAFLD and does not inhibit gallbladder emptying in mice.

Project description:Background & aimsAlcoholic liver disease (ALD) is characterized by gut dysbiosis and increased gut permeability. Hypoxia inducible factor 1α (HIF-1α) has been implicated in transcriptional regulation of intestinal barrier integrity and inflammation. We aimed to test the hypothesis that HIF-1α plays a critical role in gut microbiota homeostasis and the maintenance of intestinal barrier integrity in a mouse model of ALD.MethodsWild-type (WT) and intestinal epithelial-specific Hif1a knockout mice (IEhif1α-/-) were pair-fed modified Lieber-DeCarli liquid diet containing 5% (w/v) alcohol or isocaloric maltose dextrin for 24 days. Serum levels of alanine aminotransferase and endotoxin were determined. Fecal microbiota were assessed. Liver steatosis and injury, and intestinal barrier integrity were evaluated.ResultsAlcohol feeding increased serum levels of alanine aminotransferase and lipopolysaccharide, hepatic triglyceride concentration, and liver injury in the WT mice. These deleterious effects were exaggerated in IEhif1α-/- mice. Alcohol exposure resulted in greater reduction of the expression of intestinal epithelial tight junction proteins, claudin-1 and occludin, in IEhif1α-/- mice. In addition, cathelicidin-related antimicrobial peptide and intestinal trefoil factor were further decreased by alcohol in IEhif1α-/- mice. Metagenomic analysis showed increased gut dysbiosis and significantly decreased Firmicutes/Bacteroidetes ratio in IEhif1α-/- mice compared to the WT mice exposed to alcohol. An increased abundance of Akkermansia and a decreased level of Lactobacillus in IEhif1α-/- mice were also observed. Non-absorbable antibiotic treatment reversed the liver steatosis in both WT and IEhif1α-/- mice.ConclusionIntestinal HIF-1α is essential for the adaptative response to alcohol-induced changes in intestinal microbiota and barrier function associated with elevated endotoxemia and hepatic steatosis and injury.Lay summaryAlcohol consumption alters gut microbiota and multiple intestinal barrier protecting factors that are regulated by intestinal hypoxia-inducible factor 1α (HIF-1α). Absence of intestinal HIF-1α exacerbates gut leakiness leading to an increased translocation of bacteria and bacterial products to the liver, consequently causing alcoholic liver disease. Intestinal specific upregulation of HIF-1α could be developed as a novel approach for the treatment of alcoholic liver disease.

Dataset Information

Bile acid-receptor TGR5 deficiency worsens liver injury in alcohol-fed mice by inducing intestinal microbiota dysbiosis.

Background & aims

Methods

Results

Conclusions

Lay summary

Publications

Bile acid-receptor TGR5 deficiency worsens liver injury in alcohol-fed mice by inducing intestinal microbiota dysbiosis.

Similar Datasets

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