Project description:Rationale- NAA15 is a component of the N-terminal (Nt) acetyltransferase complex, NatA. The mechanism by which NAA15 haploinsufficiency causes congenital heart disease (CHD) remains unknown. To better understand molecular processes by which NAA15 haploinsufficiency perturbs cardiac development, we introduced NAA15 variants into human induced pluripotent stem cells (iPSCs) and assessed the consequences of these mutations on RNA and protein expression. Objective- We aim to understand the role of NAA15 haploinsufficiency in cardiac development by investigating proteomic effects on NatA complex activity, and identifying proteins dependent upon a full amount of NAA15.Methods and Results - We introduced heterozygous LoF, compound heterozygous and missense residues (R276W) in iPS cells using CRISPR/Cas9. Haploinsufficient NAA15 iPS cells differentiate into cardiomyocytes, unlike NAA15-null iPS cells, presumably due to altered composition of NatA. Mass spectrometry (MS) analyses reveal ~80% of identified iPS cell NatA targeted proteins displayed partial or complete Nt-acetylation. Between null and haploinsufficient NAA15 cells Nt-acetylation levels of 32 and 9 NatA-specific targeted proteins were reduced, respectively. Similar acetylation loss in few proteins occurred in NAA15 R276W iPSCs. In addition, steady-state protein levels of 562 proteins were altered in both null and haploinsufficient NAA15 cells; eighteen were ribosomal-associated proteins. At least four proteins were encoded by genes known to cause autosomal dominant CHD. Conclusions - These studies define a set of human proteins that requires a full NAA15 complement for normal synthesis and development. A 50% reduction in the amount of NAA15 alters levels of at least 562 proteins and Nt-acetylation of only 9 proteins. One or more modulated proteins are likely responsible for NAA15-haploinsufficiency mediated CHD. Additionally, genetically engineered iPS cells provide a platform for evaluating the consequences of amino acid sequence variants of unknown significance on NAA15 function.
Project description:NAA15 is a component of the NatA complex that acetylates amino terminal (Nt) protein residues and influences protein synthesis. We identified multiple damaging NAA15 variants in congenital heart disease patients, including four loss-of-function (LoF) variants, one missense (R276W) de novo variant and 15 rare inherited missense variants. To understand the effects of these variants on NatA complex activity, we introduced heterozygous LoF, compound heterozygous and missense residues iPS cells using CRISPR/Cas9. Haploinsufficient NAA15 iPS cells differentiate into cardiomyocytes, unlike NAA15-null iPS cells, presumably due to alterations in the amount and composition of the NatA complex. Mass spectrometry (MS)-based N-terminomics analyses showed that nearly 80% of iPS cell proteins displayed partial or complete Nt-acetylation. Between null and haploinsufficient NAA15 cells, 32 and 9 NatA-specific targeted proteins differed in their Nt-acetylation degree, respectively. In addition, the steady-state protein levels of more than 560 proteins were altered in mutant compared to wild type cells. While most NatA-specific Nt-acetylated proteins were fully acetylated, ~19 proteins were partially acetylated. NAA15-haploinsufficiency abrogated Nt-acetylation of 4 of these proteins but did not affect the acetylation of the other 15 proteins. Similar patterns of acetylation loss in few proteins were observed in both NAA15 haploinsufficient and NAA15 R276W iPS cells. These studies define human proteins that appear to require the full NAA15 complex for normal acetylation and imply that deficiencies in one or more of these NAA15 target proteins contribute to normal cardiac development. The current dataset contains all N-terminomics data related to this study.
Project description:NAA15 is a component of the NatA complex that acetylates amino terminal (Nt) protein residues and influences protein synthesis. We identified multiple damaging NAA15 variants in congenital heart disease patients, including four loss-of-function (LoF) variants, one missense (R276W) de novo variant and 15 rare inherited missense variants. To understand the effects of these variants on NatA complex activity, we introduced heterozygous LoF, compound heterozygous and missense residues iPS cells using CRISPR/Cas9. Haploinsufficient NAA15 iPS cells differentiate into cardiomyocytes, unlike NAA15-null iPS cells, presumably due to alterations in the amount and composition of the NatA complex. Mass spectrometry (MS)-based N-terminomics analyses showed that nearly 80% of iPS cell proteins displayed partial or complete Nt-acetylation. Between null and haploinsufficient NAA15 cells, 32 and 9 NatA-specific targeted proteins differed in their Nt-acetylation degree, respectively. In addition, the steady-state protein levels of more than 560 proteins were altered in mutant compared to wild type cells. While most NatA-specific Nt-acetylated proteins were fully acetylated, ~19 proteins were partially acetylated. NAA15-haploinsufficiency abrogated Nt-acetylation of 4 of these proteins but did not affect the acetylation of the other 15 proteins. Similar patterns of acetylation loss in few proteins were observed in both NAA15 haploinsufficient and NAA15 R276W iPS cells. These studies define human proteins that appear to require the full NAA15 complex for normal acetylation and imply that deficiencies in one or more of these NAA15 target proteins contribute to normal cardiac development. The current dataset contains all shotgun proteomics data related to this study.
Project description:Congenital heart defects (CHDs) are the most common major developmental anomalies and the most frequent cause for perinatal mortality, but their etiology remains often obscure. We identified a locus for CHDs on 6q24-q25. Genotype-phenotype correlations in 12 patients carrying a chromosomal deletion on 6q delineated a critical 850 kb region on 6q25.1 harboring five genes. Bioinformatics prioritization of candidate genes in this locus for a role in CHDs identified the TGF-beta-activated kinase 1/MAP3K7 binding protein 2 gene (TAB2) as the top-ranking candidate gene. A role for this candidate gene in cardiac development was further supported by its conserved expression in the developing human and zebrafish heart. Moreover, a critical, dosage-sensitive role during development was demonstrated by the cardiac defects observed upon titrated knockdown of tab2 expression in zebrafish embryos. To definitively confirm the role of this candidate gene in CHDs, we performed mutation analysis of TAB2 in 402 patients with a CHD, which revealed two evolutionarily conserved missense mutations. Finally, a balanced translocation was identified, cosegregating with familial CHD. Mapping of the breakpoints demonstrated that this translocation disrupts TAB2. Taken together, these data clearly demonstrate a role for TAB2 in human cardiac development.
Project description:Down syndrome (DS), as a typical genomic aneuploidy, is a common cause of various birth defects, among which is congenital heart disease (CHD). 40-60% neonates with DS have some kinds of CHD. However, the molecular pathogenic mechanisms of DS associated CHD are still not fully understood. This review summarizes available studies on DS associated CHD from seven aspects so as to provide a crucial and updated overview of what we known so far in this domain.
Project description:We reported the RNAseq analyses of lungs tissues in neonatal SD rats with or without reduced pulmonary blood flow(RPF). RPF was induced by causing the supravalvular pulmonary stenosis through pulmonary artery banding within 24 hours postnatally (P1). RNAseq analyses of the upper lobe of the right lung tissues was generated at P14 from 5 sham-operated rats and 5 PAB rats. The results revealed that there were 2013 differentially expressed genes between PAB and sham group at P7, among which 936 were upregulated and 1077 were downregulated. GO and KEGG pathway analysis of downregulation of DEGs indicated that abundantly enriched terms of cell migration and metabolism.
Project description:Maternal hyperglycemia increases the risk of CHD and is further sensitized by haploinsufficiency of Notch1 supporting a gene-environment interaction model. To gain insights into chromatin accessible status by which hyperglycemia affects molecular pathways regulating cardiac development, we performed ATAC-seq on embryonic AV cushion mesenchymal cells maintained in normal and high glucose.
Project description:Birth defects are the leading cause of infant mortality, and they are caused by a combination of genetic and environmental factors. Environmental risk factors may contribute to birth defects in genetically susceptible infants by altering critical molecular pathways during embryogenesis, but experimental evidence for gene-environment interactions is limited. Fetal hyperglycemia associated with maternal diabetes results in a 5-fold increased risk of congenital heart disease (CHD), but the molecular basis for this correlation is unknown. Here, we show that the effects of maternal hyperglycemia on cardiac development are sensitized by haploinsufficiency of Notch1, a key transcriptional regulator known to cause CHD. Using ATAC-seq, we found that hyperglycemia decreased chromatin accessibility at the endothelial NO synthase (Nos3) locus, resulting in reduced NO synthesis. Transcription of Jarid2, a regulator of histone methyltransferase complexes, was increased in response to reduced NO, and this upregulation directly resulted in inhibition of Notch1 expression to levels below a threshold necessary for normal heart development. We extended these findings using a Drosophila maternal diabetic model that revealed the evolutionary conservation of this interaction and the Jarid2-mediated mechanism. These findings identify a gene-environment interaction between maternal hyperglycemia and Notch signaling and support a model in which environmental factors cause birth defects in genetically susceptible infants.