miR-34a derived from adipocyte exosomes is delivered to macrophages and inhibits the expression of Krüppel-like factor 4 (KLF4) to prevent M2 polarisation, thus aggravating metabolic inflammation and insulin resistance induced by obesity.243 Of interest, exosomes from adipose tissue could promote adipogenesis and exacerbate obesity. The gene discussed is KLF4; the disease is obesity disorder.