PARP-1 inhibitor alleviates liver lipid accumulation of atherosclerosis modulating bile acid metabolism and gut microbes

Background : The DNA damage repair enzyme, poly(ADP-ribose) polymerase 1 (PARP1), is crucial for lipid and glucose metabolism. However, no evidence has been presented on the relationship between liver lipid accumulation and the PARP1 inhibitor, 3-aminobenzamide (3-AB), in atherosclerosis. Methods : ApoE −/− mice were used to explore the effect of 3-AB on atherosclerotic liver lipid accumulation, and the experiment of Sprague Dawley (SD) rats was designed to determine if the lowering of liver lipid levels by 3-AB was linked to gut bacteria. The levels of bile acid metabolism-related targets were assessed by ELISA, western blotting, and RT-qPCR. The relative abundances of gut microbes and biomarkers were determined using 16S rRNA sequencing analysis. Bile acid levels in the liver and ileum were examined by ultra-performance liquid chromatography-tandem mass spectrometry. The relationship between gut microbes and bile acids was assessed by Spearman's correlation analysis. Results : 3-AB significantly reduced the formation of aortic plaques in apoE −/− mice, according to gross oil red staining. H & E and Oil Red O staining revealed that 3-AB significantly reduced the hepatic lipid droplet area in ApoE −/− mice and SD rats. Compared with the atherosclerosis (ATH) group, 3-AB dramatically decreased the levels of total cholesterol (TC), triglyceride (TG), and low-density lipoprotein-cholesterol (LDL-C) in the serum of SD rats and apoE −/− mice, and the levels of TC, TG, and LDL-C in the serum and liver of apoE −/− mice. Furthermore, in apoE −/− mice and SD rats, 3-AB increased the mRNA and protein levels of farnesoid X receptor (FXR) and bile salt export pump (BSEP) in the liver, while inhibiting the mRNA and protein levels of FXR and fibroblast growth factor 15 (FGF15) in the ileum, respectively. 3-AB clearly inhibited the mRNA and protein levels of PARP1 in the liver and ileum of apoE −/− mice and rats. Following treatment with 3-AB, the levels of conjugated bile acids decreased in the liver of apoE −/− mice and increased in the ileum of SD rats, according to targeted metabolomic analysis. Microbiome sequencing analysis revealed that 3-AB reduced the relative abundance of Lactobacillus , Bifidobacterium , Listeria , Clostridium , Bacillus , and Staphylococcus in the feces of apoE −/− mice, and the relative abundance of Blautia , Clostridium , and Listeria in the feces of SD rats, eventually decreasing the total abundance of 10 bile salt hydrolase-associated gut