Nkx2-5 Regulates the Proliferation and Migration of H9c2 Cells

A whole-exome sequencing study of patent foramen ovale: investigating genetic variants and their association with cardiovascular disorders

Background

Patent foramen ovale (PFO) has a genetic predisposition and is closely associated with cryptogenic stroke (CS), migraine, decompression sickness, and hypoxemia. Identifying PFO-related mutant genes through whole-exome sequencing (WES) can help in the early recognition of cardiovascular genetic risk factors, guide timely clinical intervention, and reduce the occurrence of cardiovascular events.

Methods

We analyzed mutant genes from ClinVar and OMIM databases. WES was performed on 25 PFO patients from Zhejiang Provincial Hospital of Chinese Medicine. Pathogenicity of variants was evaluated using American College of Medical Genetics and Genomics (ACMG) and Association for Molecular Pathology. (AMP) guidelines.

Results

In ClinVar (4 Feb 2023), 113 coding gene mutations were found, including 83 associated with PFO. From OMIM (18 Apr 2023), 184 gene mutations were analyzed, with 110 mutant coding genes. WES identified pathogenic mutations in two of 25 PFO patients (8%). LDLR, SDHC, and NKX2-5 genes were linked to PFO and primarily involved in myocardial tissue function. NKX2-5 may play a crucial role in PFO development, interacting with NOTCH1, GATA4, MYH6, SCN5A signaling pathways regulating cardiomyocyte characteristics.

Conclusion

We identified pathogenic mutations in LDLR, SDHC, and NKX2-5 genes, implying their role in PFO development. Functional enrichment analysis revealed NKX2-5's interaction with signaling pathways regulating cardiomyocyte function. These findings enhance our understanding of PFO's genetic basis, suggesting potential therapeutic targets for future research.

Associations between NKX2-5 gene polymorphisms and congenital heart disease in the Chinese Tibetan population

BACKGROUND

The pathogenesis of congenital heart disease (CHD) has not been fully elucidated, and this study considers the interaction between inheritance and the environment as the main cause of CHD. Previous studies have found that the incidence of CHD in the Tibetan plateau population is significantly higher than in low-altitude populations. Numerous reports have confirmed that NKX2-5 gene mutations can lead to coronary heart disease, but the relationship between NKX2-5 and Tibetan nationality has not yet been reported.

OBJECTIVE

To explore the relationship between NKX2-5 gene polymorphisms and CHD in Tibetan people.

METHODS

Blood samples were collected retrospectively from Tibetan patients diagnosed with CHD as well as healthy Tibetans, and the exons of NKX2-5 were sequenced. The MassARRAY technique was used to detect and genotype candidate tag single nucleotide polymorphisms (SNPs) in the non-coding regions of NKX2-5.

RESULTS

Exon sequencing revealed no difference in the coding regions of the NKX2-5 gene between the CHD and control groups. In the non-coding regions of NKX2-5, rs6882776 and rs2546741 differed significantly between the two groups. Strong linkage disequilibrium was found between the selected sites of NKX2-5.

CONCLUSIONS

The NKX2-5 exons do not associate with CHD in Tibetans. Rs6882776 and rs2546741 in the non-coding regions of NKX2-5 may protect against CHD in Tibetans. The NKX2-5 haplotype associated with CHD occurrence in the Tibetan population.

Nkx2.5 Functions as a Conditional Tumor Suppressor Gene in Colorectal Cancer Cells via Acting as a Transcriptional Coactivator in p53-Mediated p21 Expression

NK2 homeobox 5 (Nkx2.5), a homeobox-containing transcription factor, is associated with a spectrum of congenital heart diseases. Recently, Nkx2.5 was also found to be differentially expressed in several kinds of tumors. In colorectal cancer (CRC) tissue and cells, hypermethylation of Nkx2.5 was observed. However, the roles of Nkx2.5 in CRC cells have not been fully elucidated. In the present study, we assessed the relationship between Nkx2.5 and CRC by analyzing the expression pattern of Nkx2.5 in CRC samples and the adjacent normal colonic mucosa (NCM) samples, as well as in CRC cell lines. We found higher expression of Nkx2.5 in CRC compared with NCM samples. CRC cell lines with poorer differentiation also had higher expression of Nkx2.5. Although this expression pattern makes Nkx2.5 seem like an oncogene, in vitro and in vivo tumor suppressive effects of Nkx2.5 were detected in HCT116 cells by establishing Nkx2.5-overexpressed CRC cells. However, Nkx2.5 overexpression was incapacitated in SW480 cells. To further assess the mechanism, different expression levels and mutational status of p53 were observed in HCT116 and SW480 cells. The expression of p21^WAF1/CIP1, a downstream antitumor effector of p53, in CRC cells depends on both expression level and mutational status of p53. Overexpressed Nkx2.5 could elevate the expression of p21^WAF1/CIP1 only in CRC cells with wild-type p53 (HCT116), rather than in CRC cells with mutated p53 (SW480). Mechanistically, Nkx2.5 could interact with p53 and increase the transcription of p21^WAF1/CIP1 without affecting the expression of p53. In conclusion, our findings demonstrate that Nkx2.5 could act as a conditional tumor suppressor gene in CRC cells with respect to the mutational status of p53. The tumor suppressive effect of Nkx2.5 could be mediated by its role as a transcriptional coactivator in wild-type p53-mediated p21^WAF1/CIP1 expression.