contributed equally to the research work.Abbreviations: AIM2, absent in melanoma 2; ASC, apoptosis speck-like protein; BBB, brain-blood barrier; DAMPs, damaged-associated molecular patterns; ECA, external carotid artery; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; GFAP, glial fibrillary acidic protein; HDAC3, histone deacetylases 3; Iba-1, ionized calcium binding adaptor molecule 1; LPS, lipopolysaccharide; MCAO, middle cerebral artery occlusion; NeuN, neuronal nuclei; Nrf2, nuclear factor E2-related factor-2; PYD, N-terminal pyrin domain; TTC, 2,3,5-triphenyltetrazolium chloride AbstractHistone deacetylases 3 (HDAC3) modulates the acetylation state of histone and nonhistone proteins and could be a powerful regulator of the inflammatory process in stroke. Inflammasome activation is a ubiquitous but poorly understood consequence of acute ischemic stroke. Here, we investigated the potential contributions of HDAC3 to inflammasome activation in primary cultured microglia and experimental stroke models. In this study, we documented that HDAC3 expression was increased in microglia of mouse experimental stroke model. Intraperitoneal injection of RGFP966 (a selective inhibitor of HDAC3) decreased infarct size and alleviated neurological deficits after the onset of middle cerebral artery occlusion (MCAO). In vitro data indicated that LPS stimulation evoked a time-dependent increase of HDAC3 and absent in melanoma 2 (AIM2) inflammasome in primary cultured microglia.Interestingly, AIM2 was subjected to spatiotemporal regulation by RGFP966. The ability of RGFP966 to inhibit the AIM2 inflammasome was confirmed in an experimental mouse model of stroke. As expected, AIM2 knockout mice also demonstrated significant resistance to ischemia injury compared with their wild-type littermates. RGFP966 failed to exhibit extra protective effects in AIM2−/− stroke mice. Furthermore, we found that RGFP966 enhanced STAT1 acetylation and subsequently attenuated STAT1 phosphorylation, which may at least partially contributed to the negative regulation of AIM2 by RGFP966. Together, we initially found that RGFP966 alleviated the inflammatory response and protected against ischemic stroke by regulating the AIM2 inflammasome. K E Y W O R D SAIM2 inflammasome, HDAC3, microglia, STAT1, stroke | 649 ZHANG et Al.

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