Exposure to Streptococcus anginosus facilitates lipid metabolism disorder in obese mouse model

Background Mendelian Randomization (MR) analysis can link the host gut microbiome to cardiovascular diseases. Streptococcus anginosus ( S. anginosus ) has been found to be positively correlated with early atherosclerosis, but its role in lipid metabolism remains to be explored. Methods We employed five MR analysis methods to examine the association between gut microbiota and disorders of lipoprotein metabolism. Inducing obesity in mouse models by using a high-fat diet. Throughout the experiment, we measured alterations in serum concentrations of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C). Hematoxylin and eosin (H&E) staining was utilized to assess pathological changes in adipose tissue and liver, while reverse transcription quantitative polymerase chain reaction (RT-qPCR) was conducted to evaluate changes in the expression of genes associated with triglyceride metabolism and synthesis. Results The findings from MR analysis indicate that ten specific gut microbial taxa, including Streptococcaceae , Parabacteroides goldsteinii , and Ruminococcus , exhibit a causal relationship with disorders of lipoprotein metabolism. Notably, Streptococcaceae has been identified as a risk factor for it, this result has been validated in another GWAS study. Furthermore, the presence of S. anginosus has been shown to elevate serum TG levels, diminish the accumulation of lipid droplets in both hepatic and adipose tissues, and downregulate the expression of genes associated with TG metabolism and the enzymes involved in TG synthesis. Conclusion these evidences suggest that Streptococcaceae as a risk factor for lipoprotein metabolism disorders, while S. anginosus induces TG metabolism disorders by impairing the utilization of dietary triglycerides.