Mild cold stress at ambient temperature elevates muscle calcium cycling and exercise adaptations in obese female mice

Abstract Objective Housing temperature is a critical regulator of mouse metabolism and thermoneutral housing can improve human translation. However, the impact of housing temperature on the ability of wheel running to rescue the detrimental effect of diet-induced obese mice is currently not fully understood. Methods Lean or obese female mice were housed at standard ambient temperature (22℃) or thermoneutrality (30℃) with/without access to running wheels. The metabolic phenotype was investigated using glucose tolerance tests, indirect calorimetry, and body composition. Molecular muscle adaptations were measured using immunoblotting, qPCR, and spectrophotometric/fluorescent assays. Results Obese female mice housed at 22°C showed lower adiposity, lower circulating insulin levels, improved glucose tolerance, and elevated basal metabolic rate compared to 30°C housing. Mice exposed to voluntary wheel running exhibited a larger fat loss and higher metabolic rate at 22°C housing compared to thermoneutrality. In obese female mice, glucose tolerance improved after exercise training independent of housing temperature. Independent of diet and training, 22°C housing increased skeletal muscle sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA) activity. Additionally, 22°C-housing elevated the induction of training-responsive muscle proteins in obese mice. Conclusion Our findings highlight that housing temperature significantly influences adiposity, insulin sensitivity, muscle physiology, and exercise adaptations in diet-induced obese female mice.