Circular RNA PTP4A2 regulates microglial polarization through STAT3 to promote neuroinflammation in ischemic stroke

  • CNS Neurosci Ther. 2023 Oct 23. doi: 10.1111/cns.14512.
Xingzhi Wang  1  2  3 ,  Shenyang Zhang  1  2 ,  Bingchen Lv  1  2 ,  Hao Chen  1  2 ,  Wei Zhang  1  2 ,  Liguo Dong  1  2 ,  Lei Bao  1  2 ,  Miao Wang  4 ,  Yan Wang  1  2 ,  Wenqi Mao  1  2 ,  Likun Cui  1  2 ,  Ye Pang  1  2 ,  Fei Wang  1  2 ,  Fuling Yan  5 ,  Zuohui Zhang  1  2 ,  Guiyun Cui  1  2
Affiliations
  • 1. Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China.
  • 2. Institute of Stroke Research, Xuzhou Medical University, Xuzhou, China.
  • 3. Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, China.
  • 4. Department of Geriatrics, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China.
  • 5. Department of Neurology, Affiliated to ZhongDa Hospital of Southeast University, Nanjing, China.
PMID: 37869777 DOI: 10.1111/cns.14512
Abstract

Objective: Microglial polarization plays a critical role in neuroinflammation and may be a potential therapeutic target for ischemic stroke. This study was to explore the role and underlying molecular mechanism of Circular RNA PTP4A2 (circPTP4A2) in microglial polarization after ischemic stroke.

Methods: C57BL/6J mice underwent transient middle cerebral artery occlusion (tMCAO), while primary mouse microglia and BV2 microglial cells experienced oxygen glucose deprivation/reperfusion (OGD/R) to mimic ischemic conditions. CircPTP4A2 shRNA lentivirus and Colivelin were used to knock down circPTP4A2 and upregulate signal transducer and activator of transcription 3 (STAT3) phosphorylation, respectively. Microglial polarization was assessed using immunofluorescence staining and Western blot. RNA pull-down and RNA binding protein immunoprecipitation (RIP) were applied to detect the binding between circPTP4A2 and STAT3.

Results: The levels of circPTP4A2 were significantly increased in plasma and peri-infarct cortex in tMCAO mice. CircPTP4A2 knockdown reduced infarct volume, increased cortical cerebral blood flow (CBF), and attenuated neurological deficits. It also decreased pro-inflammatory factors levels in peri-infarct cortex and plasma, and increased anti-inflammatory factors concentrations 24 h post-stroke. In addition, circPTP4A2 knockdown suppressed M1 microglial polarization and promoted M2 microglial polarization in both tMCAO mice and OGD/R-induced BV2 microglial cells. Moreover, circPTP4A2 knockdown inhibited the phosphorylation of STAT3 induced by oxygen-glucose deprivation. In contrast, increased phosphorylation of STAT3 partly counteracted the effects of circPTP4A2 knockdown. RNA pull-down and RIP assays further certified the binding between circPTP4A2 and STAT3.

Conclusion: These results revealed regulatory mechanisms of circPTP4A2 that stimulated neuroinflammation by driving STAT3-dependent microglial polarization in ischemic brain injury. CircPTP4A2 knockdown reduced cerebral ischemic injury and promoted microglial M2 polarization, which could be a novel therapeutic target for ischemic stroke.

Keywords
STAT3; circPTP4A2; inflammation; ischemic stroke; microglia.
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