Mitochondrial Energetics in Obesity-Mitochondrial Energetics in Obesity

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Video Summary

Andrea Hevener described how estrogen receptor alpha (ERα), encoded by <strong>ESR1</strong>, supports exercise adaptation and metabolic health. Across rodent and human data, higher skeletal-muscle ESR1 expression was associated with lower adiposity and better metabolic health. In mice, muscle-specific ERα deletion impaired insulin sensitivity, mitochondrial respiration and quality control, and exercise-induced mitochondrial adaptations; it also increased adiposity and reduced endurance. ERα overexpression produced exercise-like muscle changes and protected against high-fat-diet weight gain and glucose intolerance. The findings implicate the <strong>POLG1–DRP1</strong> pathway in mitochondrial DNA replication and fission, and suggest that improving ERα action could be relevant to metabolic risk during menopause.

Orian Shirihai examined mitochondria that attach to lipid droplets, called <strong>peridroplet mitochondria</strong>. In brown fat, these mitochondria differ from cytosolic mitochondria in structure and function: they favor pyruvate use and lipid synthesis, while cytosolic mitochondria are more active in fat oxidation. During cold or adrenergic stimulation, peridroplet mitochondria fragment and detach, allowing lipases greater access to stored fat. The team identified mitochondrial calcium handling as a regulator of this process: calcium accumulation promotes swelling and detachment, while calcium export through NCLX helps maintain attachment. A compound that targets this pathway promoted detachment, lipolysis and fat use in cells. Together, the talks highlighted how mitochondrial dynamics and signaling shape metabolic resilience, exercise responses and fuel use.

Keywords

estrogen receptor alpha

ESR1

metabolic health

exercise adaptation

mitochondrial dynamics

insulin sensitivity

peridroplet mitochondria

lipid droplets

brown fat

calcium signaling