STAT6/Arg1 promotes microglia/macrophage efferocytosis and inflammation resolution in stroke mice
W Cai, X Dai, J Chen, J Zhao, M Xu, L Zhang… - JCI …, 2019 - pmc.ncbi.nlm.nih.gov
JCI insight, 2019•pmc.ncbi.nlm.nih.gov
Efferocytosis, or phagocytic clearance of dead/dying cells by brain-resident microglia and/or
infiltrating macrophages, is instrumental for inflammation resolution and restoration of brain
homeostasis after stroke. Here, we identify the signal transducer and activator of
transcription 6/arginase1 (STAT6/Arg1) signaling axis as a potentially novel mechanism that
orchestrates microglia/macrophage responses in the ischemic brain. Activation of STAT6
was observed in microglia/macrophages in the ischemic territory in a mouse model of stroke …
infiltrating macrophages, is instrumental for inflammation resolution and restoration of brain
homeostasis after stroke. Here, we identify the signal transducer and activator of
transcription 6/arginase1 (STAT6/Arg1) signaling axis as a potentially novel mechanism that
orchestrates microglia/macrophage responses in the ischemic brain. Activation of STAT6
was observed in microglia/macrophages in the ischemic territory in a mouse model of stroke …
Efferocytosis, or phagocytic clearance of dead/dying cells by brain-resident microglia and/or infiltrating macrophages, is instrumental for inflammation resolution and restoration of brain homeostasis after stroke. Here, we identify the signal transducer and activator of transcription 6/arginase1 (STAT6/Arg1) signaling axis as a potentially novel mechanism that orchestrates microglia/macrophage responses in the ischemic brain. Activation of STAT6 was observed in microglia/macrophages in the ischemic territory in a mouse model of stroke and in stroke patients. STAT6 deficiency resulted in reduced clearance of dead/dying neurons, increased inflammatory gene signature in microglia/macrophages, and enlarged infarct volume early after experimental stroke. All of these pathological changes culminated in an increased brain tissue loss and exacerbated long-term functional deficits. Combined in vivo analyses using BM chimeras and in vitro experiments using microglia/macrophage-neuron cocultures confirmed that STAT6 activation in both microglia and macrophages was essential for neuroprotection. Adoptive transfer of WT macrophages into STAT6-KO mice reduced accumulation of dead neurons in the ischemic territory and ameliorated brain infarction. Furthermore, decreased expression of Arg1 in STAT6–/– microglia/macrophages was responsible for impairments in efferocytosis and loss of antiinflammatory modality. Our study suggests that efferocytosis via STAT6/Arg1 modulates microglia/macrophage phenotype, accelerates inflammation resolution, and improves stroke outcomes.
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