Mitochondrial lipoylation integrates age-associated decline in brown fat thermogenesis

Thermogenesis in brown adipose tissue (BAT) declines with age; however, what regulates this process is poorly understood. Here, we identify mitochondrial lipoylation as a previously unappreciated molecular hallmark of aged BAT in mice. Using mitochondrial proteomics, we show that mitochondrial lipoylation is disproportionally reduced in aged BAT through a post-transcriptional decrease in the iron–sulfur (Fe–S) cluster formation pathway. A defect in Fe–S cluster formation by the fat-specific deletion of Bola3 significantly reduces mitochondrial lipoylation and fuel oxidation in BAT, leading to glucose intolerance and obesity. In turn, enhanced mitochondrial lipoylation by α-lipoic acid supplementation effectively restores BAT function in old mice, thereby preventing age-associated obesity and glucose intolerance. The effect of α-lipoic acids requires mitochondrial lipoylation via the BOLA3 pathway and does not depend on the antioxidant activity of α-lipoic acid. These results open up the possibility of alleviating age-associated decline in energy expenditure by enhancing the mitochondrial lipoylation pathway. Tajima and colleagues identify mitochondrial lipoylation as a post-transcriptional molecular signature of aged brown adipose tissue (BAT) in mice. Reduced mitochondrial lipoylation is tightly coupled with the age-associated decline in BAT function, whereas enhanced lipoylation restores BAT activity in aged mice.