Scavenger receptor SRA attenuates microglia activation and protects neuroinflammatory injury in intracerebral hemorrhage.

Microglia mediated neuroinflammation plays a crucial role in intracerebral hemorrhage (ICH). Therefore, the negative feedback immune mechanism to keep microglia homeostasis and inhibit the related inflammatory injury is important. Scavenger receptor A (SRA), a pattern recognition molecule, is a physiologic negative regulator of immune consequences. However, its role in microglia mediated immune response has not been well defined. In this study, we detected SRA expression and inflammatory response of microglia treated with erythrocyte lysate in vitro, and observed the cerebral water content and neurological deficit of ICH mice in vivo. We found that SRA was highly expressed in erythrocyte lysate treated microglia. Interestingly, genetic SRA ablation increased microglia activation and cytokine production, and sensitized mice to ICH induced neuron injury. In addition, we adoptive transferred microglia (WT) into ICH mice (SRA-/-), and found that the ICH-induced inflammation injury was effectively ameliorated. Therefore, the results demonstrated that SRA could attenuate microglia mediated inflammation injury in ICH. In addition, SRA mediated negative feedback mechanism in neuroimmune homeostasis might provide a novel therapeutical strategy for ICH. Scavenger receptor SRA restrains T cell activation and protects against concanavalin A-induced hepatic injury.