In a new study published in Journal of Extracellular Vesicles, Chen-Yu Zhang’s group and Antonio Vidal-Puig’s group at University of Cambridge report that pancreatic β cells secrete miR-29 family members (miR-29a, miR-29b and miR-29c) in response to high levels of free fatty acids (FFAs). These β cell-derived miR-29s are delivered to the liver, promoting insulin resistance and enhancing hepatic glucose output.