Project description:Complex genetic inheritance is thought to underlie many human diseases, yet experimental proof of this model has been elusive. Here, we show that a human congenital heart defect, left ventricular non-compaction (LVNC), can be caused by a combination of rare, inherited heterozygous missense single nucleotide variants. Whole exome sequencing of a nuclear family revealed novel single nucleotide variants of MYH7 and MKL2 in an asymptomatic father while the offspring with severe childhood-onset LVNC harbored an additional missense variant in the cardiac transcription factor, NKX2-5, inherited from an unaffected mother. Mice bred to compound heterozygosity for the orthologous missense variants in Myh7 and Mkl2 had mild cardiac pathology; the additional inheritance of the Nkx2-5 variant yielded a more severe LVNC-like phenotype in triple compound heterozygotes. RNA sequencing identified genes associated with endothelial and myocardial development that were dysregulated in hearts from triple heterozygote mice and human induced pluripotent stem cell–derived cardiomyocytes harboring the three variants, with evidence for NKX2-5’s contribution as a modifier on the molecular level. These studies demonstrate that the deployment of efficient gene editing tools can provide experimental evidence for complex inheritance of human disease.
Project description:Complex genetic inheritance is thought to underlie many human diseases, yet experimental proof of this model has been elusive. Here, we show that a human congenital heart defect, left ventricular non-compaction (LVNC), can be caused by a combination of rare, inherited heterozygous missense single nucleotide variants. Whole exome sequencing of a nuclear family revealed novel single nucleotide variants of MYH7 and MKL2 in an asymptomatic father while the offspring with severe childhood-onset LVNC harbored an additional missense variant in the cardiac transcription factor, NKX2-5, inherited from an unaffected mother. Mice bred to compound heterozygosity for the orthologous missense variants in Myh7 and Mkl2 had mild cardiac pathology; the additional inheritance of the Nkx2-5 variant yielded a more severe LVNC-like phenotype in triple compound heterozygotes. RNA sequencing identified genes associated with endothelial and myocardial development that were dysregulated in hearts from triple heterozygote mice and human induced pluripotent stem cell–derived cardiomyocytes harboring the three variants, with evidence for NKX2-5’s contribution as a modifier on the molecular level. These studies demonstrate that the deployment of efficient gene editing tools can provide experimental evidence for complex inheritance of human disease.
Project description:NKX2-5 is a homeodomain transcription factor that plays a central role in the cardiac gene regulatory network, and is commonly mutated in human congenital heart disease. Here, we take a functional genomics approach to congenital heart disease mechanism. We used DamID to establish a robust set of target genes for both wild type NKX2-5 and a mutation lacking the homeodomain (NKX2-5delHD), the latter to model loss-of-function in gene regulatory network. NKX2-5delHD bound hundreds of targets including NKX2-5 wild type targets and a unique set of “off-targets”, and retained partial functionality. We showed that NKX2-5delHD could heterodimerize with NKX2-5 wild type and cofactors, including ubiquitous ETS family members ELK1 and ELK4, through a tyrosine-rich homophilic interaction domain (YRD). NKX2-5delHD off-targets, but not those of an NKX2-5 YRD mutant, were enriched in ETS motifs and were occupied by ELK1/ELK4 proteins, as determined by DamID. Our study reveals unexpected activities for NKX2-5 mutations on chromatin, guided by interactions with their normal cardiac and general cofactors, and suggest potential for a novel type of gain-of-function in congenital heart disease. The supplementary bed file contains all binding regions detected for the N/C-terminal fusions reported in the manuscript, in addition to probe locations, ready to upload directly into UCSC browser (mm9).
Project description:Mutations in Nkx2-5 are a main cause of cardiac congenital heart disease. Here we describe a new Nkx2-5 point-mutation murine model, akin to its human counterpart disease generating mutation. Our model fully reproduces the morphological and physiological clinical presentations of the disease and reveals an under-studied aspect of Nkx2-5 driven pathology, a primary right ventricular dysfunction. We further describe the molecular consequences of disrupting the transcriptional network regulated by Nkx2-5 in the heart and show that Nkx2-5 dependent perturbation of the Wnt signaling pathway promotes heart dysfunction through alteration of cardiomyocyte metabolism. Our data provide mechanistic insights on how Nkx2-5 regulates heart function and metabolism, a novel link in the study of congenital heart disease, and confirms that our models are the first murine genetic models to present all spectra of clinically relevant congenital heart disease phenotypes generated by Nkx2-5 mutations in patients.
Project description:Atrial specific knockout of Nkx2-5 results in hyperplastic atria with ASD and conduction defects. To examine how Nkx2-5 regulates cardiac proliferation at late gestational stages, RNA-seq was performed. Examination of expression profile of 2 Nkx2-5-null atria and 3 controls
Project description:The NKX2-1 transcription factor, a regulator of normal lung development, is the most significantly amplified gene in human lung adenocarcinoma. To better understand how genomic alterations of NKX2-1 drive tumorigenesis, we generated an expression signature associated with NKX2-1 amplification in human lung adenocarcinoma, and analyzed DNA binding sites of NKX2-1 by genome-wide chromatin immunoprecipitation from NKX2-1-amplified human lung adenocarcinoma cell lines. Combining these expression and cistromic analyses identified LMO3, itself encoding a transcription regulator, as a candidate direct transcriptional target of NKX2-1, in addition to consensus binding motifs including a nuclear hormone receptor signature and a Forkhead box motif in NKX2-1-bound sequences. RNA interference analysis of NKX2-1-amplified cells compared to non-amplified cells demonstrated that LMO3 mediates cell proliferation downstream of NKX2-1; cistromic analysis that NKX2-1 may cooperate with FOXA1. Our findings provide new insight into the transcriptional regulatory network of NKX2-1 and suggest that LMO3 is a transducer of lineage specific cell survival of NKX2-1-amplified lung adenocarcinomas. NKX2-1 ChIP-seq from three lung adenocarcinoma cell lines with amplification of NKX2-1