ABSTRACT
Nodal modulator 1 (NOMO1), a highly conserved transmembrane protein, has been identified as a part of a protein complex that participates in the Nodal signaling pathway, a critical determinant of heart and visceral organ formation. We previously found that the NOMO1 gene was substantially downregulated in human ventricular septal defect (VSD) myocardium and, thus, may be an important molecular pathway in human heart development. In this study, we aimed to investigate the effects of NOMO1 gene silencing by RNA interference (RNAi) during early mouse cardiac differentiation using P19 cells as a model system. Our results revealed that the differentiated P19 cell population exhibited downregulated NOMO1 levels and expressed lower levels of Nodal signaling mediators, such as Nodal, Cripto and Smad2, than the negative control. Similarly, cardiomyocyte-specific sarcomeric markers, such as cardiac troponin T, as well as expression of cardiogenesis-related transcriptional factors, such as Nkx2.5, Gata4 and Tbx5 were found to be downregulated in P19 differentiated cardiomyocytes in NOMO1-silenced cells when compared to controls. In conclusion, our results indicate that NOMO1 gene knockdown inhibits the differentiation of P19 cells into cardiomyocytes, which highlights a potential role for NOMO1 in early cardiogenesis.
Subject(s)
Cell Differentiation/genetics , Heart/embryology , Myocytes, Cardiac/cytology , Nodal Protein/genetics , Animals , Cell Line , Down-Regulation , Epidermal Growth Factor/biosynthesis , Epidermal Growth Factor/genetics , GATA4 Transcription Factor/biosynthesis , GATA4 Transcription Factor/genetics , Heart Septal Defects, Ventricular/genetics , Homeobox Protein Nkx-2.5 , Homeodomain Proteins/biosynthesis , Homeodomain Proteins/genetics , Membrane Glycoproteins/biosynthesis , Membrane Glycoproteins/genetics , Mice , Myocytes, Cardiac/metabolism , Neoplasm Proteins/biosynthesis , Neoplasm Proteins/genetics , RNA Interference , RNA, Messenger/biosynthesis , RNA, Small Interfering , Signal Transduction/genetics , Smad2 Protein/biosynthesis , Smad2 Protein/genetics , T-Box Domain Proteins/biosynthesis , T-Box Domain Proteins/genetics , Transcription Factors/biosynthesis , Transcription Factors/genetics , Troponin T/biosynthesis , Troponin T/geneticsABSTRACT
Exposure to persistent environmental pollutants, such as polychlorinated biphenyls (PCBs), is a risk factor for the development of congenital heart defects. MicroRNAs (miRNAs) have been shown to be involved in cardiac development. The objective of this study was to investigate changes in miRNA expression profiles during the differentiation of cardiomyocytes exposed to PCBs. For that purpose, PCBs (Aroclor 1254) at a concentration of 2.5 µmol/L were added on day 0 of differentiation of P19 mouse embryonal carcinoma cells into cardiac myocytes. The relative expression of miRNA genes was determined by miRNA microarray and real-time reverse transcriptase polymerase chain reaction (real-time RT-PCR) analyses. The microarray results revealed that 45 miRNAs, of which 14 were upregulated and 31 were downregulated, were differentially expressed in P19 cells treated with PCBs compared with control cells. The miRNA expression data was validated with real-time RT-PCR. The expression of certain potential target genes (Wnt1) was found to be reduced in P19 cells treated with PCBs, whereas the expression of other potential predicted target genes (GSK3ß) was increased. Our results demonstrate a critical role of miRNAs in mediating the effect of PCBs during the differentiation of P19 cells into cardiac myocytes.
Subject(s)
Antithyroid Agents/pharmacology , Cell Differentiation/drug effects , Gene Expression Regulation/drug effects , MicroRNAs/biosynthesis , Myocytes, Cardiac/metabolism , Animals , Cell Line, Tumor , Gene Expression Profiling , Glycogen Synthase Kinase 3/biosynthesis , Glycogen Synthase Kinase 3 beta , Mice , Myocytes, Cardiac/cytology , Oligonucleotide Array Sequence Analysis , Wnt1 Protein/biosynthesisABSTRACT
OBJECTIVES: This study was designed to determine the safety and efficiency of asymmetric and symmetric ventricular septal occluders (AVSDOs and SVSDOs, respectively) for closure perimembranous ventricular septal defect (PMVSD) in children. METHODS: Between January 2003 and December 2007, 142 children with PMVSD were treated with occluders (64 with AVSDOs and 78 with SVSDOs). RESULTS: The defect diameter was 5.3 ± 1.1 mm in the AVSDO group and 5.4 ± 1.3 mm in the SVSDO group (P > 0.05). The success rates were similar between two groups [93.8% (AVSDO) vs. 94.9% (SVSDO), P > 0.05]. Two patients in the AVSDO group were switched to the SVSDO group due to residual shunts, and one patient in the SVSDO group was switched due to aortic regurgitation after deployment of the occluder. After procedure, 17 patients [seven with AVSDOs and nine with SVSDOs (P > 0.05)] developed various types of heart block (HB). Among them, 13 patients converted to the normal sinus rhythm. The remaining four cases had not recovered at the end of the study. CONCLUSIONS: Transcatheter closure of PMVSD using both AVSDO and SVSDO was safe and effective. Development of HB was the main complication for both devices.
