RPRM deletion preserves hematopoietic regeneration by promoting EGFR‐dependent DNA repair and hematopoietic stem cell proliferation post ionizing radiation

作者：Zixuan Li, Zhou Zhou, Shuaiyu Tian, Kailu Zhang, Gangli An, Yarui Zhang, Renyuxue Ma, Binjie Sheng, Tian Wang, Hongying Yang, Lin Yang · 发表于：Cell Biology International · 年份：2022 · DOI：10.1002/cbin.11900 · 被引用次数：10 · 研究领域：Effects of Radiation Exposure、Lung Cancer Treatments and Mutations、DNA Repair Mechanisms

Reprimo (RPRM), a target gene of p53, is a known tumor suppressor. DNA damage induces RPRM, which triggers p53-dependent G2 arrest by inhibiting cyclin B1/Cdc2 complex activation and promotes DNA damage-induced apoptosis. RPRM negatively regulates ataxia-telangiectasia mutated by promoting its nuclear-cytoplasmic translocation and degradation, thus inhibiting DNA damage. Therefore, RPRM plays a crucial role in DNA damage response. Moreover, the loss of RPRM confers radioresistance in mice, which enables longer survival and less severe intestinal injury after radiation exposure. However, the role of RPRM in radiation-induced hematopoietic system injury remains unknown. Herein, utilizing a RPRM-knockout mouse model, we found that RPRM deletion did not affect steady-state hematopoiesis in mice. However, RPRM knockout significantly alleviated radiation-induced hematopoietic system injury and preserved mouse hematopoietic regeneration in hematopoietic stem cells (HSCs) against radiation-induced DNA damage. Further mechanistic studies showed that RPRM loss significantly increased EGFR expression and phosphorylation in HSCs to activate STAT3 and DNA-PKcs, thus promoting HSC DNA repair and proliferation. These findings reveal the critical role of RPRM in radiation-induced hematopoietic system injury, confirming our hypothesis that RPRM may serve as a novel target for radiation protection.