Ampuja Minna, Ericsson Sabina, Paatero Ilkka, Chowdhury Iftekhar, Villman Jenna, Broberg Martin, Ramste Amanda, Balboa Diego, Ojala Tiina, Chong Jessica X, Bamshad Michael J, Priest James R, Varjosalo Markku, Kivelä Riikka, Helle Emmi
Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland.
HGG Adv. 2025 Jul 10;6(3):100446. doi: 10.1016/j.xhgg.2025.100446. Epub 2025 May 5.
Non-syndromic congenital heart defects (CHDs) are occasionally familial and left ventricular outflow tract obstruction (LVOTO) defects are among the subtypes with the highest hereditability. The aim of this study was to evaluate the pathogenicity of a heterozygous ERBB2 variant c.1795C>T, p.Arg599Cys identified in three families with LVOTO defects. Variant detection was done with exome sequencing. Western blotting, digital PCR, mass spectrometry (MS), MS microscopy, and flow cytometry were used to study the function of the ERBB2 variant c.1795C>T. Cardiac structure and function were studied in zebrafish embryos expressing human ERBB2 wild type or c.1795C>T. Proband-derived human induced pluripotent stem cell cardiomyocytes (hiPS-CMs) and endothelial cells (hiPS-ECs) were used for transcriptomic analyses. While phosphorylation of the ERBB2 p.Arg599Cys receptor was not altered, the variant affected dramatically the binding partners of the protein, indicating mislocalization of the mutant ERBB2 from plasma membrane to endoplasmic reticulum. Expression of human ERBB2 p.Arg599Cys in zebrafish embryos resulted in cardiomyocyte hypertrophy, increased cardiac wall thickness, and impaired fractional shortening. Transcriptomic analyses of hiPS-ECs and hiPS-CMs from an individual with the c.1795C>T variant showed aberrant expression of genes related to cardiovascular system development and abnormal response to oxidative stress in both cell types. In conclusion, the heterozygous variant ERBB2 c.1795C>T, p.Arg599Cys leads to abnormal cellular localization of the ERBB2 receptor and induces structural changes and dysfunction in the zebrafish embryo heart. This evidence expands previous findings from animal studies to humans and suggests variants in ERBB2 may be associated with CHD.
非综合征性先天性心脏病（CHD）偶尔具有家族性，左心室流出道梗阻（LVOTO）缺陷是遗传性最高的亚型之一。本研究的目的是评估在三个患有LVOTO缺陷的家族中鉴定出的杂合ERBB2变体c.1795C>T、p.Arg599Cys的致病性。通过外显子组测序进行变体检测。使用蛋白质免疫印迹、数字PCR、质谱（MS）、MS显微镜和流式细胞术研究ERBB2变体c.1795C>T的功能。在表达人ERBB2野生型或c.1795C>T的斑马鱼胚胎中研究心脏结构和功能。使用先证者来源的人诱导多能干细胞心肌细胞（hiPS-CMs）和内皮细胞（hiPS-ECs）进行转录组分析。虽然ERBB2 p.Arg599Cys受体的磷酸化没有改变，但该变体显著影响了该蛋白的结合伙伴，表明突变型ERBB2从质膜错误定位到内质网。人ERBB2 p.Arg599Cys在斑马鱼胚胎中的表达导致心肌细胞肥大、心脏壁厚度增加和缩短分数受损。对来自携带c.1795C>T变体个体的hiPS-ECs和hiPS-CMs进行的转录组分析显示，两种细胞类型中与心血管系统发育相关的基因表达异常以及对氧化应激的异常反应。总之，杂合变体ERBB2 c.1795C>T、p.Arg599Cys导致ERBB2受体的细胞定位异常，并在斑马鱼胚胎心脏中诱导结构变化和功能障碍。这一证据将先前动物研究的结果扩展到了人类，并表明ERBB2中的变体可能与CHD有关。
