GSE185395
A human hereditary cardiomyopathy shares a genetic substrate with bicuspid aortic valve
The complex genetics underlying human cardiac disease is evidenced by its heterogenous manifestation, multigenic basis and sporadic occurrence. These features have hampered disease modelling and mechanistic understanding. Here, we show that two structural cardiac diseases, left ventricular non-compaction (LVNC) and bicuspid aortic valve (BAV), can be caused by a combined set of inherited heterozygous mutations. We used CRISPR-Cas9 gene editing to generate mice harboring two mutations in the NOTCH ligand regulator MINDBOMB1 identified in LVNC families. One Mib1 mutation causes LVNC only in heteroallelic combination with a conditional Mib1 allele, while the other leads to BAV in a NOTCH-sensitized genetic background. These data suggest that the LVNC phenotype may be influenced by genetic modifiers present in these families, while valve defects are very sensitive to NOTCH haploinsufficiency. Whole-exome sequencing revealed single-nucleotide variants in the ASXL3, APCDD1 and TMX3, CEP192 and BCL7A genes, co-segregating with the MIB1 mutations and LVNC. We generated mice harboring the orthologous variants in the corresponding Mib1 backgrounds. Triple heterozygous Mib1 Apcdd1 Asxl3 mutants show LVNC, while quadruple heterozygous Mib1 Cep192 Tmx3;Bcl7a mice show BAV and other valve-associated defects. Biochemical assays suggest interactions between CEP192, BCL7A and NOTCH. Gene profiling of murine hearts and human induced pluripotent stem cell-derived cardiomyocytes reveals defective metabolic maturation. These findings provide evidence for a common genetic substrate for LVNC and BAV involving MIB1 and genetic modifiers Overall design: RNA was isolated at E15.5 from ventricles of Control (Mib1flox/+; Tnnt2-Cre/+) and Mib1R530X/flox; Tnnt2-Cre/+, and WT and Mib1R530X/+ Asxl3M1361V/+ Apcdd1V150I/+ embryos. Samples were distributed in three pools of four pairs of ventricles per genotype. Tissue was homogenized with a pestle mechanical homogenizer and RNA was extracted using RNEasy Mini Kit (Qiagen, 74104). RNA libraries were prepared using the NEB Next Ultra II Directional RNA Library Prep Kit and sequenced in a HiSeq2500 Illumina sequencer using a 60?bp single end elongation protocol.