Kou Shan, Lu Zhengkai, Deng Defang, Ye Min, Sui Yu, Qin Lieyang, Feng Teng, Jiang Zhen, Meng Jufeng, Lin Chao-Po, Li Xiajun, Liu Chen, Tang Juan, Zhang Hui
School of Life Science and Technology (S.K., D.D., M.Y., Y.S., T.F., Z.J., J.M., C.L., X.L., H.Z.), ShanghaiTech University, Shanghai, China.
State Key Laboratory of Cardiovascular Diseases and Medical Innovation Center, Shanghai East Hospital, Frontier Science Center for Stem Cell Research, School of Life Science and Technology, Tongji University, Shanghai, China (S.K., Z.L., J.T.).
Circulation. 2025 Mar 4;151(9):623-639. doi: 10.1161/CIRCULATIONAHA.124.070738. Epub 2024 Dec 20.
Cardiac fibrosis, characterized by excessive extracellular matrix (ECM) deposition in the myocardium, is an important target for heart disease treatments. (paternally expressed gene 3) is an imprinted gene expressed from the paternal allele, and de novo purine biosynthesis (DNPB) is a crucial pathway for nucleotide synthesis. However, the roles of PW1 and DNPB in ECM production by cardiac fibroblasts during myocardial ischemia are not yet understood.
To induce myocardial damage, we performed left anterior descending coronary artery ligation. We generated and knock-in mouse lines to evaluate the expression of the 2 alleles in normal and injured hearts. Bisulfite sequencing was used to analyze the DNA methylation of the imprinting control region. We identified the phosphoribosylformylglycinamidine synthase () gene, encoding the DNPB enzyme PFAS, as a direct target of PW1 using chromatin immunoprecipitation sequencing and real-time quantitative polymerase chain reaction. The role of DNPB in ECM production and cardiac fibrosis after injury was examined in vitro using cultured cardiac fibroblasts and in vivo with -deficient mice.
Our study demonstrates that myocardial infarction reduces DNA methylation at the imprinting control region of the maternally imprinted gene , triggering a switch from monoallelic imprinting to biallelic expression of in cardiac fibroblasts. In activated cardiac fibroblasts, increased expression promotes purine biosynthesis and induces ECM production by transcriptionally activating the DNPB factor . We identified that DNPB is essential for ECM production in activated fibroblasts and that loss of in fibroblasts limits cardiac fibrosis and improves heart function after injury.
This study demonstrates that imprinting is disrupted after injury and reveals a novel role for the downstream target PFAS in ECM production and cardiac fibrogenesis. Targeting the PW1/PFAS signaling pathway presents a promising therapeutic strategy for improving cardiac repair after injury.
心肌纤维化以心肌细胞外基质（ECM）过度沉积为特征，是心脏病治疗的重要靶点。父系表达基因3（PW1）是一种从父本等位基因表达的印记基因，而从头嘌呤生物合成（DNPB）是核苷酸合成的关键途径。然而，PW1和DNPB在心肌缺血期间心脏成纤维细胞产生ECM中的作用尚不清楚。
为诱导心肌损伤，我们进行了左前降支冠状动脉结扎。我们构建了PW1和PFAS敲入小鼠品系，以评估这两个等位基因在正常和受损心脏中的表达。亚硫酸氢盐测序用于分析PW1印记控制区域的DNA甲基化。我们使用染色质免疫沉淀测序和实时定量聚合酶链反应，确定编码DNPB酶PFAS的磷酸核糖甲酰甘氨脒合酶（PFAS）基因是PW1的直接靶点。使用培养的心脏成纤维细胞在体外以及使用PFAS缺陷小鼠在体内研究了DNPB在损伤后ECM产生和心脏纤维化中的作用。
我们的研究表明，心肌梗死会降低母系印记基因PW1印记控制区域的DNA甲基化，从而引发心脏成纤维细胞中从单等位基因印记到双等位基因表达的转变。在活化的心脏成纤维细胞中，PW1表达增加会促进嘌呤生物合成，并通过转录激活DNPB因子PFAS来诱导ECM产生。我们确定DNPB对活化的成纤维细胞中ECM的产生至关重要，并且成纤维细胞中PFAS的缺失会限制心脏纤维化并改善损伤后的心脏功能。
本研究表明损伤后PW1印记被破坏，并揭示了下游靶点PFAS在ECM产生和心脏纤维生成中的新作用。靶向PW1/PFAS信号通路为改善损伤后心脏修复提供了一种有前景的治疗策略。
