Genetic deletion of microRNA-15a/16-1 in pericytes stimulates cerebral angiogenesis and promotes functional recovery after ischemic stroke.

Abstract

Stroke is a leading cause of mortality and disability globally. Despite advancements in acute stroke therapies, patient outcomes with ischemic stroke remain suboptimal. Understanding its molecular mechanisms is crucial for developing effective treatments. Angiogenesis actively contributes to post-stroke functional recovery and improves long-term survival in stroke patients. Pericytes are essential for maintaining vascular stability and promoting angiogenesis. We hypothesized that microRNA-15a/16-1 in pericytes significantly modulates post-stroke angiogenesis and neurological recovery. Using a pericyte-specific miR-15a/16-1 conditional knockout (cKO) mouse model, we found that genetic deletion of miR-15a/16-1 in pericytes enhances angiogenesis, promotes cerebral blood flow recovery, and improves sensorimotor and cognitive outcomes following ischemic stroke. Mechanistically, RNA sequencing identified several novel targets of miR-15a/16-1, including Pappa2, Fgf9, Islr, and Ccr2. Interestingly, Pappa2, Fgf9, and Islr function as secreted proteins. Luciferase reporter assays demonstrated that miR-15a/16-1 directly binds and suppresses Pappa2, Fgf9, Islr, and Ccr2 activity in cultured pericytes. In vivo and in vitro assays further confirmed that miR-15a/16-1 silencing in pericytes significantly elevates the protein levels of Pappa2, Fgf9, Islr, and Ccr2 and enhances endothelial cell proliferation, migration, and tube formation under ischemic conditions. These findings suggest that targeting miR-15a/16-1 in pericytes offers a promising therapeutic strategy for enhancing stroke recovery by promoting neurovascular repair and reducing brain damage.