Premium
Increased intracellular calcium is a mediator of heat stress induced adipocyte hypertrophy
Author(s) -
Ajuwon Kolapo M,
Qu Huan
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.915.27
Subject(s) - calcium , calcium in biology , chemistry , endoplasmic reticulum , intracellular , unfolded protein response , microbiology and biotechnology , ionomycin , endocrinology , medicine , biochemistry , biology , organic chemistry
Exposure of porcine preadipocytes to heat stress (41.5°C) during differentiation results in increased intracellular triglyceride storage, characterized by elevated expression of glyceroneogenic genes such as phosphoenolpyruvate carboxykinase (PCK1) and glycerol kinase (GK), compared to cells differentiated at control (37°C) temperature. However, the molecular mediators of this response are unknown. Therefore, we investigated the role of calcium in this response. Compared to cells differentiated at control temperature, heat stress results in increased intracellular calcium release from the endoplasmic reticulum(ER) in response to ionomycin (2μM), suggesting that heat stress may promote increased ER calcium storage. To determine wether calcium plays a role in the increased lipid storage during heat stress, cells were treated with or without the calcium chelator, FURA2‐AM, during differentiation. Treatment with FURA2‐AM resulted in reduced lipid storage in response to heat stress, suggesting that calcium may play a role in the stress‐induced lipid storage. We also investigated the potential role of calcium channels TRPV1 and TRPV3 because of their implication in heat sensing mechanism. The use of inhibitors to both channels, AMG 9810 (5μM) and DPTHF (100μM), resulted in reduction in intracellular calcium and triglyceride concentrations. Therefore, the TRP channels may play a role in the elevated intracellular calcium concentration in adipocytes during heat stress. The implication of the increased ER calcium release on ER stress and lipid synthesis is still being investigated.