Intercellular mitochondria transfer to macrophages regulates white adipose tissue homeostasis and is impaired in obesity

Brestoff et al. show, for the first time, that mitochondria are transferred from adipocytes to macrophages and that this event has an impact on systemic metabolic homeostasis.Within the last years, it has been demonstrated that cells are able to communicate with each other by the exchange of organelles, such as lysosomes and mitochondria, and this gained considerable interest in different fields of medicine. Intercellular exchange of mitochondria can take place by several mechanisms, including tunnelling microtubes, extracellular vesicles, or cell fusion (1). Moreover, mitochondria appear to be transported systemically as well, as they are frequently found in the circulation (2). Whether or not mitochondrial transfer takes place in the adipose tissue had not been investigated so far. The authors used a transplantation mouse model, in which mitochondria in the adipose tissue were specifically labelled. They showed a directed transfer of mitochondria from adipocytes to macrophages, which was dependent on the presence of heparan sulphate on the surface of macrophages. This transport was diminished in high-fat-diet (HDF) obesity, and conversely, inhibition of mitochondrial transfer resulted in metabolic dysfunction.