San1 deficiency leads to cardiomyopathy due to excessive R-loop-associated DNA damage and cardiomyocyte hypoplasia

BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR BASIS OF DISEASE

卷:1867

Article

Liu, Zhiheng¹  Gao, Xu¹  Zhou, Zhou¹  Kang, Sung Wook²  Yang, Yong¹  Liu, Hao¹  Zhang, Chunqin³  Wen, Zheng¹  Rao, Xiaoquan¹  Wang, Daowen¹  White, Donnell²  Yang, Qinglin²  Long, Qinqiang^1,4 

[1] Huazhong Univ Sci & Technol, Tongji Med Coll, Tongji Hosp, Div Cardiol,Dept Internal Med, 1095 Jiefang Ave, Wuhan 430030, Peoples R China

[2] Louisan State Univ, Hlth Sci Ctr, Cardiovasc Ctr Excellence, 533 Bolivar St 4th Fl,Rm 416, New Orleans, LA 70112 USA

[3] Nanjing Med Univ, Affiliated Suqian Peoples Hosp 1, Dept Emergency, Suqian 223800, Peoples R China

[4] Guangdong Pharmaceut Univ, Inst Chinese Med, Guangdong Metab Dis Res Ctr Integrated Chinese &, Guangzhou Higher Educ Mega Ctr, 280 Wai Huan Dong Rd, Guangzhou 510006, Peoples R China

关键词: San1;    R-loops;    DNA damage;    Cardiomyocytes proliferation;    Heart development;   

DOI  :  10.1016/j.bbadis.2021.166237

来源: Elsevier

【 摘 要 】

R-loops are naturally occurring transcriptional intermediates containing RNA/DNA hybrids. Excessive R-loops cause genomic instability, DNA damage, and replication stress. Senataxin-associated exonuclease (San1) is a protein that interacts with Senataxin (SETX), a helicase resolving R-loops. It remains unknown if R-loops-induced DNA damage plays a role in the heart, especially in the proliferative neonatal cardiomyocytes (CMs). San1-/- mice were generated using the CRISPR/Cas9 technique. The newborn San1-/- mice show no overt phenotype, but their hearts were smaller with larger, yet fewer CMs. CM proliferation was impaired with reduced cell cycle-related transcripts and proteins. S9.6 staining revealed that excessive R-loops accumulated in the nucleus of neonatal San1-/- CMs. Increased gamma H2AX staining on newborn and adult heart sections exhibited increased DNA damage. Similarly, San1-/- AC16-cardiomyocytes showed cumulative R-loops and DNA damage, leading to the activation of cell cycle checkpoint kinase ATR and PARP1 hyperactivity, arresting G2/M cell-cycle and CM proliferation. Together, the present study uncovers an essential role of San1 in resolving excessive R-loops that lead to DNA damage and repressing CM proliferation, providing new insights into a novel biological function of San1 in the neonatal heart. San1 may serve as a novel therapeutic target for the treatment of hypoplastic cardiac disorders.

【 授权许可】

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