DataSheet1_Craniofacial and cardiac defects in chd7 zebrafish mutants mimic CHARGE syndrome.pdf

Congenital heart defects occur in almost 80% of patients with CHARGE syndrome, a sporadically occurring disease causing craniofacial and other abnormalities due to mutations in the CHD7 gene. Animal models have been generated to mimic CHARGE syndrome; however, heart defects are not extensively described in zebrafish disease models of CHARGE using morpholino injections or genetic mutants. Here, we describe the co-occurrence of craniofacial abnormalities and heart defects in zebrafish chd7 mutants. These mutant phenotypes are enhanced in the maternal zygotic mutant background. In the chd7 mutant fish, we found shortened craniofacial cartilages and extra cartilage formation. Furthermore, the length of the ventral aorta is altered in chd7 mutants. Many CHARGE patients have aortic arch anomalies. It should be noted that the aberrant branching of the first branchial arch artery is observed for the first time in chd7 fish mutants. To understand the cellular mechanism of CHARGE syndrome, neural crest cells (NCCs), that contribute to craniofacial and cardiovascular tissues, are examined using sox10:Cre lineage tracing. In contrast to its function in cranial NCCs, we found that the cardiac NCC-derived mural cells along the ventral aorta and aortic arch arteries are not affected in chd7 mutant fish. The chd7 fish mutants we generated recapitulate some of the craniofacial and cardiovascular phenotypes found in CHARGE patients and can be used to further determine the roles of CHD7.

CHARGE综合征（CHARGE syndrome）是一种散发型遗传病，由CHD7基因突变引发，可导致颅面部及其他组织异常，近80%的该综合征患者会出现先天性心脏缺损。目前已有研究者构建了模拟CHARGE综合征的动物模型，但针对通过吗啉代（morpholino）注射或构建遗传突变体得到的斑马鱼CHARGE疾病模型，其心脏缺损表型尚未得到充分阐述。本研究首次报道了斑马鱼chd7突变体中同时存在颅面部异常与心脏缺损的表型，且该突变表型在母源合子突变（maternal zygotic mutant）背景下会进一步加重。在chd7突变斑马鱼中，我们观察到颅面部软骨缩短以及额外软骨生成，同时腹主动脉的长度发生异常改变。多数CHARGE综合征患者存在主动脉弓畸形，值得注意的是，我们首次在chd7斑马鱼突变体中观察到第一鳃弓动脉的分支异常。为阐明CHARGE综合征的细胞机制，我们利用sox10:Cre谱系示踪技术，对参与颅面部及心血管组织发育的神经嵴细胞（neural crest cells, NCCs）进行了检测。结果发现，与颅神经嵴的功能不同，沿腹主动脉和主动脉弓动脉分布的心脏神经嵴来源的周细胞在chd7突变斑马鱼中并未受到影响。本研究构建的chd7斑马鱼突变体复现了CHARGE综合征患者的部分颅面部及心血管表型，可用于后续进一步探究CHD7的具体作用机制。