Project description:Homozygous deletion of the SNX17 gene in rats resulted in mid-gestational embryonic lethality which was accompanied by congenital heart defects, including in the double-outlet right ventricle, atrioventricular and ventricular septal defects. To elucidate the potential mechanisms underlying development of cardiac OFT defects induced by SNX17 knockout, we performed RNA-seq analysis in cardiac outflow tract (OFT) tissues isolated from WT and HO embryos at E13.5. A total of 262 differentially expressed genes (DEGs) were identified between WT and HO samples, of which 94 and 168 were up-regulated and down-regulated, respectively. Analysis of biological functions of the DEGs, via Gene Ontology (GO), revealed that the up-regulated genes were mainly involved in heart development, and negative regulation of the intrinsic apoptotic pathway, while the down-regulated DEGs were associated with cell adhesion, extracellular organization, and negative regulation of the Wnt signaling pathway.
Project description:Sorting nexin 17 (SNX17), a member of sorting nexin (SNX) family, acts as a modulator for endocytic recycling of membrane proteins. Results from our previous study demonstrated the embryonic lethality of homozygous defect of SNX17. In this study, we investigated the role of SNX17 in rat fetal development. Specifically, we analyzed patterns of SNX17 messenger RNA (mRNA) expression in multiple rat tissues and found high expression in the cardiac outflow tract (OFT). This expression was gradually elevated during the cardiac OFT morphogenesis. Homozygous deletion of the SNX17 gene in rats resulted in mid-gestational embryonic lethality, which was accompanied by congenital heart defects, including the double-outlet right ventricle and atrioventricular and ventricular septal defects, whereas heterozygotes exhibited normal fetal development. Moreover, we found normal migration distance and the number of cardiac neural crest cells during the OFT morphogenesis. Although cellular proliferation in the cardiac OFT endocardial cushion was not affected, cellular apoptosis was significantly suppressed. Transcriptomic profiles and quantitative real-time PCR data in the cardiac OFT showed that SNX17 deletion resulted in abnormal expression of genes associated with cardiac development. Overall, these findings suggest that SNX17 plays a crucial role in cardiac development.
Project description:During development the fetal heart undergoes a rapid and dramatic transition to adult function through transcriptional and post-transcriptional mechanisms, including alternative splicing (AS). We performed deep RNA-sequencing for high-resolution analysis of transcriptome changes during postnatal mouse heart development using RNA from ventricles and freshly isolated cardiomyocytes (CM) and cardiac fibroblasts (CF). Extensive changes in gene expression and AS occur primarily between postnatal days 1 and 28. CM and CF showed reciprocal regulation of gene expression during postnatal development reflecting differences in proliferative capacity, cell adhesion functions, and mitochondrial metabolism. We found that AS plays a novel role in vesicular trafficking and membrane organization during postnatal CM development. Interestingly, these AS transitions are enriched among targets of two RNA-binding proteins, Celf1 and Mbnl1, which undergo developmentally regulated change in expression. Vesicular traffic genes affected by AS during normal development where Celf1 is down-regulated, showed a reversion to neonatal AS patterns when Celf1 was over-expressed in adults. RNA-seq was performed in RNA samples of ventricles, cardiomyocytes or cardiac fibroblast at different developmental stages; embryonic day 17, postnatal day (PN) 1, 10, 28 and 90 for ventricles, PN1-3, PN28 and PN60 for cardiac fibroblasts, and PN1-2, PN30, and PN67 for cardiomyocytes
Project description:Aims: MiRNAs are post-transcriptional regulatory molecules with recognized roles in human heart development and disease. The purpose of this study was to define human miRNA expression profile in cardiac progenitors and early-differentiated cardiomyocytes and to determine if these miRNAs that are governing cardiogenesis is dependent on NKX2-5, a highly conserved pan-cardiac transcription factor. Methods: MiRNA expression profiles of pre-NKX2-5 mesoderm, cardiac progenitors and early cardiomyocytes derived from heterozygous HES3 NKX2-5eGFP/w and null NKX2-5eGFP/eGFP hESC lines were generated by small RNA sequencing in triplicates, using Illumina HiSeq. Reads between 17-28 base pairs were selected for sequence alignment to the human genome (hg19) using Bowtie2. FeatureCounts (Subread, R package) was used to count the number of reads mapping to miRNAs and analysis of statistically differentially expressed miRNA was carried out using Limma (Bioconductor) through the statistical language R. qRT–PCR validation was performed using Taqman MicroRNA Assays. Results: We identified 11 miRNAs that were differentially expressed between pre-NKX2-5 mesoderm and cardiac progenitors, and 112 differentially expressed miRNAs between cardiac progenitors and early cardiomyocytes. Four of which were validated with qRT–PCR, including canonical myogenic miRNAs such as MIR-1-1, -133A1 and 208A that were enriched in both the cardiac progenitor and early cardiomyocyte populations. Strikingly, deletion of NKX2-5 did not result in gross changes in cardiac miRNA profile either at progenitor or cardiomyocyte stage. Instead, non-hierarchical clustering and principal component analysis demonstrated that the different stages of differentiation (day 6 vs day 10) was a larger discriminator between samples than NKX2-5 genotype. Conclusion: Our study demonstrates the application of human embryonic stem cells as an in vitro model to investigate the role of miRNAs in human cardiac development. We conclude that while specific miRNAs have been identified in our study to have a role in the early stages cardiac cell fate specification, the majority of cardiac myogenic miRNA program is regulated separately from the highly conserved NKX2-5 -dependent gene network. This study provides a framework for further investigation of other key transcription factors of cardiac muscle development that might drive cardiomyogenic expression of miRNAs.
Project description:Alternative splicing is critical for development. However, its role in the specification of the three embryonic germ layers is poorly understood. By performing RNA-Seq on human embryonic stem cells (hESCs) and derived endoderm, cardiac mesoderm, and ectoderm cell lineages, we detect distinct alternative splicing programs associated with each lineage. The most prominent splicing program differences are observed between definitive endoderm and cardiac mesoderm. Integrative multi-omics analyses link each program with lineage-specific RNA binding protein regulators, and further suggest a widespread role for Quaking (QKI) in the specification of cardiac mesoderm. Remarkably, knockout of QKI disrupts the cardiac mesoderm-associated alternative splicing program and formation of myocytes. These changes likely arise in part through reduced expression of BIN1 splice variants linked to cardiac development. Collectively, our results thus uncover alternative splicing programs associated with the three germ lineages and demonstrate an important role for QKI in the formation of cardiac mesoderm.
Project description:microRNAs regulate cardiac hypertrophy development, which predicts the risk of heart failure. Here we investigate the role of microRNA-204-5p (miR-204) in developing cardiac hypertrophy and cardiac dysfunction following transaortic constriction. To determine the role of miR-204, we determined the transcriptomic profile of hearts following transaortic constriction.
Project description:Two different mouse models of cardiac-specific ILK expression (ILKS343D and ILKR211A) were used to investigate the role of ILK in cardiac regeneration 4 groups with 3 mice (biological replicates) in each group with the total of 12 heart samples were used in this microarray experiment