Activating CD137 Signaling Promotes Sprouting Angiogenesis via Increased VEGFA Secretion and the VEGFR2/Akt/eNOS Pathway

Figure 8

Graphical abstract. Activation of CD137 signaling promoted sprouting angiogenesis via increased VEGFA secretion and the VEGFR2/Akt/eNOS pathway. CD137 upregulated the expression of VEGFR2 on the filopodia of migrating endothelial cells to sense VEGFA in the milieu. Therefore, increased VEGFA secretion together with the VEGFR2 activation induced downstream Akt/eNOS transduction, leading to proliferation, migration, and angiogenesis.