Exosomal miR-34a: the code for adipocyte-macrophage communication

The study “Adipocyte-secreted exosomal microRNA-34a inhibits M2 macrophage polarization to promote obesity-induced adipose inflammation”, presented by Pan et al. and published in J Clin Invest, has been read by us with great interest (1). In this study, the authors uncovered adipocyte-secreted exosomes as a potentially novel mediator of obesity-induced adipose inflammation, acting by transporting miR-34a into the adjacent macrophages, where it drives the polarization program toward proinflammatory M1 phenotype by targeting the transcription factor KLF4. Indeed, this study provided a new question for obesity-induced systemic inflammation and metabolic dysregulation, but in terms of the molecular mechanism of miR-34a on M1/M2 polarization, there still are something to clarify and need for more investigation.