Sphingolipid metabolism and insulin resistance - Does cannabigerol protect against experimental colitis induced by high-fat high-sucrose diet?

Abstract

Metabolic disturbances, including sphingolipid dysregulation and insulin resistance, play a crucial role in the pathogenesis of colon disorders. Excessive consumption of a high-fat high-sucrose diet (HFHS) exacerbates these conditions, contributing to colonic inflammation and impaired glucose metabolism. The herein study aimed to assess the potential protective effect of cannabigerol (CBG), a non-psychoactive phytocannabinoid, on sphingolipid metabolism and insulin signaling in a rat model of experimental colitis induced by an HFHS diet. Male Wistar rats were divided into four groups: standard diet, standard diet + CBG, HFHS diet, and HFHS diet + CBG. CBG was administered intragastrically at 30 mg/kg body mass during the last 14 days of a six-week feeding period. Sphingolipid fractions were quantified by high-performance liquid chromatography, while insulin signaling components were assessed using multiplex immunoassays, immunoblotting and molecular docking simulations. Immunoblotting was also used to measure the expression of proteins involved in sphingolipid metabolism. Immunohistochemical staining was used to assess inflammatory cell infiltration. CBG supplementation significantly reduced ceramide levels and restored sphingosine-1-phosphate concentrations, thus improving the S1P/CER ratio in colon tissue of HFHS-fed rats. In HFHS-fed rats CBG also modulated the expression of key enzymes from sphingolipid pathways, specifically a diminution in the expression of SPTLC1, SPTLC2, CerS2, ASAH1, ASAH2, N-SMase and Alk-SMase, accompanied by a simultaneous increase in the expression of SPHK1 and CerS6. CBG also enhanced the phosphorylation ratio of critical insulin pathway proteins, including pIRS1/IRS1, pAkt/Akt, pGSK3β/GSK3β and pmTOR/mTOR. Molecular docking revealed the stable binding of CBG to pPTEN and pS6RP, suggesting a direct interaction that contributes to its beneficial effects. CBG also reduced the level of inflammatory markers like CD68 and F4/80. These findings suggest that CBG alleviates HFHS-induced colitis possibility by modulating sphingolipid metabolism and restoring insulin signaling, supporting its potential as a therapeutic agent in colon function disturbances associated with metabolic disorders.

Keywords: Cannabigerol; Colon tissue; Insulin resistance; Metabolic disorder; Sphingolipid.