The intricate interplay between the gut microbiota and host metabolism plays a pivotal role in regulating glucose and lipid homeostasis, with bile acids (BAs) emerging as key signaling molecules. BAs, synthesized in the liver through two distinct pathways, impact metabolic diseases like obesity and nonalcoholic fatty liver disease. The alternative BA synthetic pathway, often overlooked, holds promise in treating hyperglycemia and fatty liver disease by modulating BA signaling. By exploring this pathway, novel pharmacological strategies could be developed to combat metabolic disorders more effectively.
The gut microbiota’s involvement in BA metabolism underscores its significance in regulating BA-receptor signaling pathways, influencing glucose and lipid metabolism. The complex interplay of primary and secondary BAs, modified by gut microbiota, highlights the critical role of BA homeostasis in metabolic disorders. The classic and alternative BA synthetic pathways, regulated by key enzymes like CYP7A1 and CYP27A1, offer insights into the modulation of BA composition to influence metabolic outcomes.
Activation of BA receptors like TGR5 and FXR regulates glucose and lipid metabolism, with potential therapeutic implications for metabolic diseases. The alternative BA synthetic pathway, though less explored, demonstrates its impact on energy expenditure, insulin sensitivity, and lipid metabolism. By targeting enzymes like CYP7B1 in this pathway, metabolic phenotypes can be improved, offering a novel avenue for developing metabolic disease therapies.
The alternative BA synthetic pathway also plays a crucial role in producing oxysterols, bioactive lipids involved in cholesterol metabolism and liver homeostasis. Oxysterols, derived from cholesterol oxidation, serve as LXR agonists and influence RCT, lipid metabolism, and glucose homeostasis. Dysregulation of this pathway is associated with metabolic disorders such as NAFLD and insulin resistance, highlighting its importance in maintaining metabolic balance.
In advanced stages of NAFLD progressing to NASH and liver cancer, alterations in the alternative BA synthetic pathway become prominent. The upregulation of this pathway, potentially as a compensatory mechanism, aims to alter BA composition for improved excretion of BAs. However, the delicate balance in the expression of key enzymes like CYP7B1 is crucial, as increased oxysterol levels can lead to pro-inflammatory responses and liver damage.
Understanding the intricate mechanisms of the alternative BA synthetic pathway offers new avenues for managing metabolic diseases. By targeting this pathway and modulating BA composition, therapeutic strategies can be tailored to address metabolic disorders more effectively. Further research into the role of oxysterols, enzyme regulation, and gut microbiota interactions in this pathway is essential for developing precision therapies for metabolic diseases.
Tags: downstream, secretion, regulatory, chaperones, metabolomics, microbiome
Read more on pmc.ncbi.nlm.nih.gov