β-arrestin 2 protects neurological function defect in HSV-1- induced encephalitis mice.

The pathogenesis of herpes simplex encephalitis (HSE) needs to be fully explored. beta-Arrestin 2 (Arrb2) is highly expressed in brain tissues and plays a key role in the regulation of systemic immune reactions by modulating various signaling pathways. However, the expression of Arrb2 in microglial cells and its influence on HSE prognosis is still undefined. We explore the pathophysiological effect of Arrb2 in the brain using experimental HSE mice. The expression of Arrb2 in microglia was decreased significantly 48 hours following HSV-1 infection. Arrb2 overexpression transgenic (TG) mice had a significantly lower mortality and survival rate was improved by 40% compared to wild-type mice. Arrb2 suppressed the generation of proinflammatory cytokines TNF-alpha and IL-6 and increased anti-inflammatory cytokines IL-10 and IL-4 expression. Arrb2 also inhibited the activation of the transcription factor NF-kappa B in microglial cells. Arrb2 TG mice attenuated the blood-brain barrier breakdown and relieved cerebral edema, meanwhile, Arrb2 improved mice neurological function compared with wild-type mice. Overall, Arrb2 favored microglia of the M2 phenotype, attenuated brain proinflammatory responses, protected the blood vessel wall integrity, reduced HSV-1-induced neurological impairment, and improved the survival rate in HSE mice.