BMPR2 affected valve development via ECM-receptor interaction in zebrafish

Yan Shi^1,2Yanli Huang³Yu Xia⁴Yongqing Li⁵Yuequn Wang⁵Wuzhou Yuan⁵Fang Li⁵Zhigang Jiang⁵Yu Chen¹Ping Zhu^1,6Jian Zhuang^1,2*Xiushan Wu^4,5*Xiongwei Fan^5*

• ¹Medical Research Institute, Guangdong Provincial People’s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510080, Guangdong, China, Guangzhou, China
• ²Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong Provincial People’s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University,, Guangzhou, China
• ³The Laboratory of Heart Development Research, College of Life Science, Hunan Normal University., Changsha, China
• ⁴Department of Cardiothoracic Surgery, Guangdong Provincial Hospital of Chinese Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
• ⁵The Laboratory of Heart Development Research, College of Life Science, Hunan Normal University, Changsha, China
• ⁶Guangdong Provincial Key Laboratory of Pathogenesis, Targeted Prevention and Treatment of Heart Disease, Guangzhou Key Laboratory of Cardiac Pathogenesis and Prevention, Guangzhou, China

Abnormal cardiac valve development may lead to functional impairment in adulthood. BMPR2, a highly conserved receptor of the BMP family, exists in two subtypes (bmpr2a and bmpr2b) in zebrafish. However, the roles of bmpr2a and bmpr2b in valve development remain unclear. In this study, we generated three bmpr2a/b mutant zebrafish strains, bmpr2a-and bmpr2b-knockout zebrafish (bmpr2a-/- and bmpr2b-/-, respectively) using CRISPR/Cas9, and bmpr2a and bmpr2b double-knockout zebrafish (bmpr2a-/-;bmpr2b-/-) according bmpr2a-/- and bmpr2b-/- hybridization. Using cardiac function assessment (M-mode), we characterized the cardiac developmental phenotypes of the three zebrafish mutant strains. Transcriptomic profiling (RNA-seq) was combined with whole-mount in situ hybridization (WISH) and qRT-PCR to validate gene expression changes. The results showed that bmpr2a-/-, bmpr2b-/- and bmpr2a-/-;bmpr2b-/- mutant zebrafish strains displayed valve developmental defects at 52 hpf, followed by cardiac contractile dysfunction. RNA-seq revealed upregulation of cardiac markers (myl9a, myl9b, tnnc1a, cmlc1, myl7, nppa) and valve-related genes (fn1b, has2, nfatc1), along with downregulation of klf2a, as validated by WISH and qRT-PCR. Pathway analysis identified the ECM-receptor interaction as a key regulatory axis of bmpr2a/b-mediated valve development. This study demonstrated that bmpr2a and bmpr2b cooperatively regulate cardiac contractile function and valve development in zebrafish, providing insights into BMPR2-mediated cardiovascular morphogenesis in humans.