High-Fat Diet Remodels Plasma Membrane Rigidity to Potentiate Colonocyte Stemness in Mice.

BACKGROUND & AIMS: Obesity and consumption of a high-fat diet are established risk factors for colorectal cancer. However, the cellular mechanisms linking dietary lipid exposure to intestinal stem cell dysregulation remain incompletely defined. We therefore investigated whether a high-fat diet perturbs plasma membrane homeostasis to potentiate colonocyte stemness in mice.

METHODS

Mice were placed on a chronic 12-week high-fat diet or control (low-fat diet) feeding regimen, or a short-term 1-week high-fat diet exposure. In addition, genetically obese leptin receptor-deficient (db/db) vs (db/+) wild-type mice were examined. Membrane free cholesterol and rigidity were quantified in colonic crypts and leucine-rich repeat-containing G-protein coupled receptor 5+ intestinal stem cells utilizing Filipin III and Di-4-ANEPPDHQ dyes, respectively. Membrane receptor nanoclustering of epidermal growth factor receptor and low-density lipoprotein receptor-related protein 6 was assessed by super-resolution microscopy. β-catenin activation, stem cell frequency, proliferation, and organoid-forming efficiency were also evaluated by immunostaining, flow cytometry, and ex vivo organoid assays.

RESULTS

Chronic high-fat diet feeding in mice increased membrane free cholesterol content and rigidity in colonic stem cells and enhanced epidermal growth factor receptor and low-density lipoprotein receptor-related protein 6 receptor nanoclustering. This alteration in plasma membrane homeostasis resulted in the overactivation of β-catenin and expansion of the intestinal stem cell niche (eg, stem cell proliferation and organoid-forming efficiency). Notably, genetically induced obesity in db/db mice did not recapitulate the high-fat diet membrane phenotype, highlighting a diet-specific effect.

CONCLUSIONS

Collectively, these findings identify plasma membrane remodeling as a previously unrecognized mechanism linking dietary lipids to aberrant intestinal stem cell homeostasis and colorectal cancer risk.