PDGFRβ-P2A-CreER mice: a genetic tool to target pericytes in angiogenesis.

Pericytes are essential mural cells distinguished by their association with small caliber blood vessels and the presence of a basement membrane shared with endothelial cells. Pericyte interaction with the endothelium plays an important role in angiogenesis; however, very few tools are currently available that allow for the targeting of pericytes in mouse models, limiting our ability to understand their biology. We have generated a novel mouse line expressing tamoxifen-inducible Cre-recombinase under the control of the platelet-derived growth factor receptor β promoter: PDGFRβ-P2A-CreER . We evaluated the expression of the PDGFRβ-P2A-CreER line by crossing it with fluorescent reporter lines and analyzed reporter signal in the angiogenic retina and brain at different time points after tamoxifen administration. Reporter lines showed labeling of NG2, desmin, PDGFRβ perivascular cells in the retina and the brain, indicating successful targeting of pericytes; however, signal from reporter lines was also observed in a small subset of glial cells both in the retina and the brain. We also evaluated recombination in tumors and found efficient recombination in perivascular cells associated with tumor vasculature. As a proof of principle, we used our newly generated driver to delete Notch signaling in perivascular cells and observed a loss of smooth muscle cells in retinal arteries, consistent with previously published studies evaluating Notch3 null mice. We conclude that the PDGFRβ-P2A-CreER line is a powerful new tool to target pericytes and will aid the field in gaining a deeper understanding of the role of these cells in physiological and pathological settings.