Platelet-Derived Growth Factor-D Activates Complement System to Propagate Macrophage Polarization and Neovascularization

Front Cell Dev Biol. 2021 Jun 2:9:686886. doi: 10.3389/fcell.2021.686886. eCollection 2021.

Abstract

Platelet-derived growth factor-D (PDGF-D) is highly expressed in immune cells. However, the potential role of PDGF-D in immune system remains thus far unclear. Here, we reveal a novel function of PDGF-D in activating both classical and alternative complement pathways that markedly increase chemokine and cytokine responses to promote macrophage polarization. Pharmacological targeting of the complement C3a receptor using SB290157 alleviated PDGF-D-induced neuroinflammation by blocking macrophage polarization and inhibited pathological choroidal neovascularization. Our study thus suggests that therapeutic strategies targeting both PDGF-D and the complement system may open up new possibilities for the treatment of neovascular diseases.

Keywords: C1qa; C3; PDGF-D; inflammation; macrophage polarization.