Rare genetic variants in GATA transcription factors in patients with hypertrophic cardiomyopathy

Targeting GATA6 with pedunculoside inhibits fetal gene expression to attenuate pathological cardiac hypertrophy

BACKGROUND

Pathological cardiac hypertrophy is a characteristic feature of numerous cardiovascular diseases and significantly impacts human health. However, effective treatment options for cardiac hypertrophy are still significantly unmet. Pedunculoside, a pentacyclic triterpenoid saponin from the traditional Chinese herb Ilex rotunda Thunb., exhibits various pharmacological properties such as anti-inflammatory and cardiovascular therapeutic effects, but its anti-hypertrophy efficacy and mechanisms have not yet been reported.

PURPOSE

This study aimed to confirm the ameliorating effect of pedunculoside on cardiac hypertrophy and elucidate its underlying mechanism.

METHODS

To investigate the effect of pedunculoside on cardiac hypertrophy, we used transverse aortic constriction (TAC) and isoproterenol hydrochloride (ISO) infusion to induce cardiac hypertrophy model in mice. Angiotensin II (Ang II) was used to mimic hypertrophy model in myocardial cells. Then, we utilized a biotin-tagged carabrone chemical probe and validation experiments to pinpoint pedunculoside's key targets. Further, molecular docking study and sites mutation were used to predict and identify the binding modes of pedunculoside to target. Finally, structural optimization was carried out to find new pedunculoside derivatives with stronger anti-hypertrophy activity and binding affinity to the target.

RESULTS

Our findings revealed for the first time that pedunculoside treatment significantly attenuated hypertrophic phenotypes in response to TAC and ISO. It also effectively reduced hypertrophy and fibrosis in myocardial cells exposed to Ang II stimulation. Mechanically, we identified transcription factor GATA-6 (GATA6) as a key target of pedunculoside for treating cardiac hypertrophy. Further studies demonstrated that pedunculoside blocks cardiac hypertrophy progression by inhibiting the transcriptional activation of GATA6 on promoting fetal gene expression. More importantly, a new pedunculoside derivative PE-3 with stronger anti-hypertrophy activity and affinity for GATA6 was discovered.

CONCLUSION

Our findings suggest that pedunculoside and PE-3 could be developed as promising drug candidates for cardiac hypertrophy treatment.

Identification of biomarkers associated with energy metabolism in hypertrophic cardiomyopathy and exploration of potential mechanisms of roles

Background

In hypertrophic cardiomyopathy (HCM), limited reports exist regarding its association with energy metabolism. Here, biomarkers related to energy metabolism in HCM were identified through bioinformatics analysis.

Methods

HCM transcriptome data were acquired from the GEO (GSE36961) database for comparative analysis in order to identify differentially expressed genes (DEGs). Subsequently, the identified DEGs were intersected with key module genes in Weighted gene co-expression network analysis (WGCNA) and energy metabolism related genes (EMRGs) to identify DE-EMRGs. Then, feature biomarkers were screened using the least absolute shrinkage and selection operator (LASSO) regression and support vector machine-recursive feature elimination (SVM-RFE) methods, and the intersection of the feature biomarkers obtained from both methods was used for subsequent analysis. Furthermore, biomarkers defined as biomarkers with consistent expression trends across both GSE36961 and GSE89714 datasets and significant inter-cohort differences were selected for subsequent analysis. Subsequently, an immune analysis was conducted. Additionally, the transcription factors (TFs), and drugs regulating the biomarkers were predicted based on online databases.

Results

The co-selection of seven potential biomarkers based on machine learning identified IGFBP3 and JAK2 as biomarkers in HCM. Upregulation of IGFBP3 and JAK2 in the HCM cohort was observed in the GSE36961 and GSE89714 datasets. Utilizing ssGSEA, it was unveiled that the HCM cohort exhibited elevated ratings of effector memory CD4T cells while displaying diminished scores across 22 other immune cell categories. Notably, JAK2 expression exhibited a strong negative correlation with myeloid-derived suppressor cells (MDSCs) infiltration, while IGFBP3 showed no significant associations with immune cell infiltration. Utilizing NetworkAnalyst, miRNAs and TFs regulating biomarkers expression in HCM were predicted, with hsa-mir-16-5p, hsa-mir-147a, hsa-mir-210b-3p, hsa-let-7b-5p, and hsa-mir-34a-5p identified as regulators of both IGFBP3 and JAK2. GATA2 was also found to be a TF regulating the expression of both biomarkers. Furthermore, the potential therapeutic targets of JAK2 and IGFBP3 in HCM were ruxolitinib and celecoxib, respectively.

Conclusion

In conclusion, the identification of IGFBP3 and JAK2 as biomarkers in HCM, highlight promising avenues for further research and treatment development in HCM.

Genetics in Congenital Heart Diseases: Unraveling the Link Between Cardiac Morphogenesis, Heart Muscle Disease, and Electrical Disorders

The genetic background of congenital heart diseases (CHDs) is extremely complex, heterogenous, and still majorly to be determined. CHDs can be sporadic or familial. In this article we discuss in detail the phenotypic spectrum of selected genes including MYH7, GATA4, NKX2-5, TBX5, and TBX20. Our goal is to offer the clinician a general overview of the clinical spectrum of the analyzed topics that are traditionally known as causative for CHDs but we underline in this review the possible progressive functional (cardiomyopathy) and electric aspects (arrhythmias) caused by the genetic background.

Systemic Bioinformatic Analyses of Nuclear-Encoded Mitochondrial Genes in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is an autosomal dominant disease and mitochondria plays a key role in the progression in HCM. Here, we analyzed the expression pattern of nuclear-encoded mitochondrial genes (NMGenes) in HCM and found that the expression of NMGenes was significantly changed. A total of 316 differentially expressed NMGenes (DE-NMGenes) were identified. Pathway enrichment analyses showed that energy metabolism-related pathways such as "pyruvate metabolism" and "fatty acid degradation" were dysregulated, which highlighted the importance of energy metabolism in HCM. Next, we constructed a protein-protein interaction network based on 316 DE-NMGenes and identified thirteen hubs. Then, a total of 17 TFs (transcription factors) were predicted to potentially regulate the expression of 316 DE-NMGenes according to iRegulon, among which 8 TFs were already found involved in pathological hypertrophy. The remaining TFs (like GATA1, GATA5, and NFYA) were good candidates for further experimental verification. Finally, a mouse model of transverse aortic constriction (TAC) was established to validate the genes and results showed that DDIT4, TKT, CLIC1, DDOST, and SNCA were all upregulated in TAC mice. The present study represents the first effort to evaluate the global expression pattern of NMGenes in HCM and provides innovative insight into the molecular mechanism of HCM.

Unusual Cause of Bidirectional Ventricular Rhythm

Bidirectional ventricular tachycardia (BDVT), a rare ventricular arrhythmia, is commonly caused by digitalis toxicity or channelopathies and is rarely caused by aconite toxicity, myocarditis, infarction, or sarcoidosis. This paper describes a patient with BDVT, recurrent syncope, myocardial disarray, and interstitial fibrosis on histology but normal results on echocardiography with variants in the TTN, KCNH2, and GATA4 genes. (Level of Difficulty: Advanced.)

Variants in cardiac GATA genes associated with bicuspid aortic valve

BACKGROUND

Bicuspid aortic valve (BAV) is a heterogeneous and still not fully understood condition, with diverse genetic aetiology and associated phenotypes ranging from aortic stenosis or regurgitation to aneurysm and dissection. Several genes have been associated with the presence of BAV, notably some members of the GATA family of transcription factors that play important roles in cardiac embryogenesis.

METHODS

A case-control study with 122 unrelated and ethnically matched patients with bicuspid and 154 with tricuspid aortic valve was performed. All exons of GATA4, GATA5, and GATA6 genes were sequenced searching for variants. Frequencies were compared and functional effects of rare variants were analysed by informatic prediction tools.

RESULTS

Four rare and potentially pathogenic variants were identified in only five sporadic cases: a missense p.Arg202Gln (rs782614097) in GATA5 and three synonymous variants, p.Cys274= (rs55980825) and p.His302= (rs201516339) in GATA4, and p.Asn458= (rs143026087) in GATA6. Minor alleles of p.His302=, p.Arg202Gln and rs3764962 are enriched in BAV patients compared to ExAC database (P = 0.01, 0.03, and 0.01 respectively). In addition, a common polymorphism in GATA5 (p.Asp203=, rs41305803) is associated with BAV showing a protective effect in carriers of the minor allele (OR [95%CI] = 0.45[0.25-0.81]; P = 0.004).

CONCLUSION

This study associates additional genetic variants in GATA4 and GATA5 with BAV, supporting the implication of these genes in the development of this valvulopathy. The discovery of all the genetic factors involved will contribute to a better understanding of the process and, therefore, to detect a genetic predisposition and even to the identification of therapeutic targets.