Bioenergetic adaptations of small intestinal epithelial cells reduce cell differentiation enhancing intestinal permeability in obese mice

Background: Obesity and overweight are associated with low-grade inflammation induced by adipose tissue expansion and perpetuated by altered intestinal homeostasis, including increased epithelial permeability. Intestinal epithelium functions are supported by intestinal epithelial cells (IEC) mitochondria function.

Methods and results: Here, we report that diet-induced obesity (DIO) in mice induces lipid metabolism adaptations favoring lipid storage in IEC together with reduced number, altered dynamics and diminished oxidative phosphorylation activity of IEC mitochondria. Using the jejunal epithelial cell line IPEC-J2, we showed that IEC lipid metabolism and oxidative stress machinery adaptations preceded mitochondrial bioenergetic ones. Moreover, we unraveled the intricate link between IEC energetic status and proliferation / differentiation balance since enhancing mitochondrial function with the AMPK activator AICAR in jejunal organoids reduced proliferation and initiated IEC differentiation and conversely. We confirmed that the reduced IEC mitochondrial function observed in DIO mice was associated with increased proliferation and reduced differentiation, promoting expression of the permissive Cldn2 in the jejunal epithelium of DIO mice.

Conclusions: Our study provides new insights into metabolic adaptations of IEC in obesity by revealing that excess lipid intake diminishes mitochondrial number in IEC, reducing IEC differentiation that contribute to increased epithelial permeability.