Celastrol modulates calcium signaling in mouse taste bud cells and gustatory preference for a dietary fatty acid in the mouse

Abstract

Celastrol, a terpenoid, has been shown to exert several beneficial properties in health and disease, particularly in obesity. Recent studies have demonstrated that orosensory detection of dietary fatty acids plays an important role in the pathogenesis of obesity. In the present report, we have studied the role of celastrol in the modulation of calcium signaling in Fluo-4/AM loaded mouse taste bud cells (mTBC) and fat taste perception in the mouse. Celastrol was found to induce increases in free intracellular calcium concentrations, [Ca²⁺]i, in mTBC. Celastrol seems to exert its action via bile acid TGR5 (Takeda-G-protein-receptor-5) receptor. Furthermore, U-73122, a phospholipase C (PLC) inhibitor, significantly curtailed celastrol-induced calcium signaling, suggesting that this agent triggers an increase from endoplasmic reticulum via inositol-tris-phosphate (IP₃) production. Celastrol-recruited Ca²⁺ from intracellular pool that triggered the opening of TRPC3 channels. We further employed thapsigargin (TG), known to trigger an increase in [Ca²⁺]i. Celastrol shared the TG-recruited Ca²⁺ pool. Celastrol was observed to share linoleic acid-triggered Ca²⁺ signaling in these cells. In two-bottle choice paradigm, celastrol increased the gustatory preference for linoleic acid. Our study might be helpful for considering the synthesis of celastrol analogues as fat taste modifiers with a potential in the management of obesity.