Intestinal FGF15 regulates bile acid and cholesterol metabolism but not glucose and energy balance

Document Type

Article

Publication Date

4-8-2024

Institution/Department

Center for Molecular Medicine

Journal Title

JCI insight

MeSH Headings

Animals; Humans; Mice; Bile Acids and Salts; Cholesterol (metabolism); Diabetes Mellitus, Type 2; Glucose; Non-alcoholic Fatty Liver Disease; Obesity (metabolism)

Abstract

Fibroblast growth factor 15/19 (FGF15/19, mouse/human ortholog) is expressed in the ileal enterocytes of the small intestine and released postprandially in response to bile acid absorption. Previous reports of FGF15-/- mice have limited our understanding of gut-specific FGF15's role in metabolism. Therefore, we studied the role of endogenous gut-derived FGF15 in bile acid, cholesterol, glucose, and energy balance. We found that circulating levels of FGF19 were reduced in individuals with obesity and comorbidities, such as type 2 diabetes and metabolic dysfunction-associated fatty liver disease. Gene expression analysis of ileal FGF15-positive cells revealed differential expression during the obesogenic state. We fed standard chow or a high-fat metabolic dysfunction-associated steatohepatitis-inducing diet to control and intestine-derived FGF15-knockout (FGF15INT-KO) mice. Control and FGF15INT-KO mice gained similar body weight and adiposity and did not show genotype-specific differences in glucose, mixed meal, pyruvate, and glycerol tolerance. FGF15INT-KO mice had increased systemic bile acid levels but decreased cholesterol levels, pointing to a primary role for gut-derived FGF15 in regulating bile acid and cholesterol metabolism when exposed to obesogenic diet. These studies show that intestinal FGF15 plays a specific role in bile acid and cholesterol metabolism regulation but is not essential for energy and glucose balance.

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