Neuroinflammation after ischemic stroke involves INPP5D expression mediated by the TMPO-AS1-PU.1 complex

Objectives: This study aims to explore the role of lncRNA TMPO-AS1 in ischemic stroke and corresponding mechanism.

Methods: Adult male C57BL/6 J mice were subjected to a middle cerebral artery occlusion (MCAO) model of ischemic stroke, then TMPO-AS1 shRNA lentivirus were injected into ipsilateral striatum of mice. The neurological score and cerebral infarction volume were evaluatedHypoxia/glucose deprivation/reoxygenation (OGD/R)-induced BV2 cells were transfected with TMPO-AS1 shRNA (sh-TMPO-AS1) or together with pcDNA-INPP5D, as well as transfected with sh-PU.1 or together with pcDNA-INPP5D, then TMPO-AS1 level, the expression of PU.1 and INPP5D proteins, the secretion of inflammatory factors (TNF-α, IL-6 and IL-1β), the levels of iNOS, CD68,Arg1 and CD206 mRNA were detected. RIP and PNA-pull down assays were used to detect the binding of TMPO-AS1 and PU.1, luciferase reporter gene and chromatin immunoprecipitation (ChIP) assays were used to detect the binding activity of PU.1 and INPP5D.

Results: TMPO-AS1 level was increased in peripheral blood of ischemic stroke patients , brain tissues of MCAO/R model mice and OGD/R-induced BV2 cells. TMPO-AS1 interference inhibited the inflammation of OGD/R-induced BV2 cells. TMPO-AS1 also enhanced the nuclear accumulation of PU.1 by binding to the transcription factor PU.1, and promoted the transcriptional activation of INPP5D. The anti-inflammatory effects of TMPO-AS1 interference were reversed by INPP5D overexpression. In addition, TMPO-AS1 interference improved the infarct volume of MCAO mice, and improved sensorimotor and cognitive functions.

Conclusion: INPP5D underexpression mediated by TMPO-AS1-PU.1 complex alleviated neuroinflammation after ischemic stroke.

BV2 cells; INPP5D; Ischemic stroke; PU.1; TMPO-AS1.