Heterogeneous Expression of SDF1 Retains Actively Proliferating Neural Progenitors in the Capillary Compartment of the Niche

Summary: The vascular compartment of the adult brain ventricular-subventricular zone (V-SVZ) is a critical regulator of neural stem cell and progenitor function. Blood enters the V-SVZ via arteries and arterioles to capillaries that then connect with venules and veins to return blood to the heart. We found that stromal cell-derived factor 1 (SDF1) is expressed by a subpopulation of V-SVZ vessels, the capillaries, and that actively proliferating neural stem cells (NSCs) and progenitors are preferentially associated with these SDF1-positive vessels. In contrast, slowly dividing or quiescent NSCs are most prevalent near SDF1-negative vessels. By conditional knockout, we found that loss of SDF1 signaling in NSCs stimulates lineage progression and NSC displacement from the vessel niche. With aging, SDF1/CXCR4 signaling is dysregulated, coincident with reduced proliferation and increased displacement of dividing cells from the vasculature. Our findings demonstrate SDF1-based vascular heterogeneity in the niche and suggest that reduced SDF1 signaling contributes to age-related declines in adult neurogenesis. : The vascular compartment of the adult neurogenic niche is a major regulatory hub for neural stem cells. Here, Kokovay and colleagues show that the chemokine SDF1 is expressed by a subset of the blood vessels within the niche associated with proliferating progenitors. Knockdown of the SDF1 receptor leads to aberrant lineage progression. Keywords: neural stem cells, SDF1, CXCL14, CXCR4, blood vessels, vasculature, nich