Brain immune cells undergo cGAS/STING-dependent apoptosis during herpes simplex virus type 1 infection to limit type I IFN production


Protection of the brain from viral infections involves the type I IFN (IFN-I) system, defects in which render humans susceptible to herpes simplex encephalitis (HSE). However, excessive cerebral IFN-I levels lead to pathologies, suggesting the need for tight regulation of responses. Based on data from mouse models, human HSE cases, and primary cell culture systems, we showed that microglia and other immune cells undergo apoptosis in the HSV-1-infected brain through a mechanism dependent on the cyclic GMP-AMP synthase/stimulator of interferon genes (cGAS/STING) pathway, but independent of IFN-I. HSV-1 infection of microglia induced cGAS-dependent apoptosis at high viral doses, whereas lower viral doses led to IFN-I responses. Importantly, inhibition of caspase activity prevented microglial cell death and augmented IFN-I responses. Accordingly, HSV-1-infected organotypic brain slices or mice treated with a caspase inhibitor exhibited lower viral load and an improved infection outcome. Collectively, we identify an activation-induced apoptosis program in brain immune cells that downmodulates local immune responses.

Authors Reinert LS, Rashidi AS, Tran DN, Katzilieris-Petras G, Hvidt AK, Gohr M, Fruhwürth S, Bodda C, Thomsen MK, Vendelbo MH, Khan AR, Hansen B, Bergström P, Agholme L, Mogensen TH, Christensen MH, Nyengaard JR, Sen GC, Zetterberg H, Verjans GM, Paludan SR
Journal The Journal of clinical investigation
Publication Date 2021 Jan 4;131(1)
PubMed 32990676
PubMed Central PMC7773356
DOI 10.1172/jci136824

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