KAP1 phosphorylation promotes the survival of neural stem cells after ischemia/reperfusion by maintaining the stability of PCNA

  • Stem Cell Res Ther. 2022 Jul 7;13(1):290. doi: 10.1186/s13287-022-02962-5.
Wan Wang   #  1  2 ,  Tianqing Yan   #  1 ,  Xinjian Guo   #  1 ,  Heng Cai  1 ,  Chang Liang  3 ,  Linyan Huang  1 ,  Yanling Wang  1 ,  Ping Ma  4  5 ,  Suhua Qi  6  7
Affiliations
  • 1. School of Medical Technology, Xuzhou Key Laboratory of Laboratory Diagnostics, Xuzhou Medical University, Xuzhou, 221004, China.
  • 2. Department of Laboratory Medicine, Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221002, China.
  • 3. School of Basic Medical Science, Xuzhou Medical University, Xuzhou, 221004, China.
  • 4. School of Medical Technology, Xuzhou Key Laboratory of Laboratory Diagnostics, Xuzhou Medical University, Xuzhou, 221004, China. [email protected].
  • 5. Department of Laboratory Medicine, Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221002, China. [email protected].
  • 6. School of Medical Technology, Xuzhou Key Laboratory of Laboratory Diagnostics, Xuzhou Medical University, Xuzhou, 221004, China. [email protected].
  • 7. Pharmacology College, Xuzhou Medical University, Xuzhou, 221004, China. [email protected].
  • # Contributed equally.
PMID: 35799276 DOI: 10.1186/s13287-022-02962-5
Abstract

Aims: To explore the function of phosphorylation of KAP1 (p-KAP1) at the serine-824 site (S824) in the proliferation and Apoptosis of endogenous neural stem cells (NSCs) after cerebral ischemic/reperfusion (I/R).

Methods: The Apoptosis and proliferation of C17.2 cells transfected with the p-KAP1-expression plasmids and the expression of proliferation cell nuclear antigen (PCNA) and p-KAP1 were detected by immunofluorescence and Western blotting after the Oxygen Glucose deprivation/reperfusion model (OGD/R). The interaction of p-KAP1 and CUL4A with PCNA was analyzed by immunoprecipitation. In the rats MCAO model, we performed the adeno-associated virus (AAV) 2/9 gene delivery of p-KAP1 mutants to verify the proliferation of endogenous NSCs and the colocalization of PCNA and CUL4A by immunofluorescence.

Results: The level of p-KAP1 was significantly down-regulated in the stroke model in vivo and in vitro. Simulated p-KAP1(S824) significantly increased the proliferation of C17.2 cells and the expression of PCNA after OGD/R. Simulated p-KAP1(S824) enhanced the binding of p-KAP1 and PCNA and decreased the interaction between PCNA and CUL4A in C17.2 cells subjected to OGD/R. The AAV2/9-mediated p-KAP1(S824) increased endogenous NSCs proliferation, PCNA expression, p-KAP1 binding to PCNA, and improved neurological function in the rat MCAO model.

Conclusions: Our findings confirmed that simulated p-KAP1(S824) improved the survival and proliferation of endogenous NSCs. The underlying mechanism is that highly expressed p-KAP1(S824) promotes binding to PCNA, and inhibits the binding of CUL4A to PCNA. This reduced CUL4A-mediated ubiquitination degradation to increase the stability of PCNA and promote the survival and proliferation of NSCs.

Keywords
Cerebral ischemia/reperfusion (I/R); KRAB domain protein 1(KAP1); Neural stem cells (NSCs); PCNA; Proliferation.
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