Epigenetic Regulation of Cardiac Troponin Genes in Pediatric Patients with Heart Failure Supported by Ventricular Assist Device

Abstract

Ventricular Assist Device (VAD) therapy is considered as a part of standard care for end-stage Heart Failure (HF) children unresponsive to medical management, but the potential role of miRNAs in response to VAD therapy on molecular pathways underlying LV remodeling and cardiac function in HF is unknown. The aims of this study were to evaluate the effects of VAD on miRNA expression profile in cardiac tissue obtained from HF children, to determine the putative miRNA targets by an in-silico analysis as well as to verify the changes of predicated miRNA target in the same cardiac samples. The regulatory role of selected miRNAs on predicted targets was evaluated by a dedicated in vitro study. miRNA profile was determined in cardiac samples obtained from 13 HF children [median: 29 months; 19 LVEF%; 9 Kg] by NGS before VAD implant (pre-VAD) and at the moment of heart transplant (Post-VAD). Only hsa-miR-199b-5p, hsa-miR-19a-3p, hsa-miR-1246 were differentially expressed at post-VAD when compared to pre-VAD, and validated by real-time PCR. Putative targets of the selected miRNAs were involved in regulation of sarcomere genes, such as cardiac troponin (cTns) complex. The expression levels of fetal ad adult isoforms of cTns resulted significantly higher after VAD in cardiac tissue of HF pediatric patients when compared with HF adults. An in vitro study confirmed a down-regulatory effect of hsa-miR-19a-3p on cTnC expression. The effect of VAD on sarcomere organization through cTn isoform expression may be epigenetically regulated, suggesting for miRNAs a potential role as therapeutic targets to improve heart function in HF pediatric patients.

Changes in adiponectin system after ventricular assist device in pediatric heart failure

“… 3 Our previous study suggested that VAD heart unloading was able to modify the expression of specific microRNA (miRNAs) in HF pediatric patients. 9 The hsa-miR-1246, hsa-miR-199b-5p, and hsa-miR-19a-3p were differentially expressed after VAD implant and were able to regulate the expression of cardiac troponins. 9 In addition to sarcomere proteins, in silico analysis suggested the adiponectin (ADPN) system, including ADPN and its receptors, as a putative target of selected miRNAs ( Figure 1 ).…”

“… 9 The hsa-miR-1246, hsa-miR-199b-5p, and hsa-miR-19a-3p were differentially expressed after VAD implant and were able to regulate the expression of cardiac troponins. 9 In addition to sarcomere proteins, in silico analysis suggested the adiponectin (ADPN) system, including ADPN and its receptors, as a putative target of selected miRNAs ( Figure 1 ). 9 ADPN is an adipocyte-derived protein with the anti-inflammatory, anti-hypertrophic, anti-apoptotic, and anti-fibrotic role in the heart.…”

“…At molecular level, the mechanisms associated with left ventricle (LV) remodeling and pediatric HF progression include the chronic activation of both sympathetic nervous system and renin-angiotensin-aldosterone system (RAAS), the sarcomere proteins’ dysfunction, the cardiac fetal genes re-expression, and the epigenetic modifications. 3 , 9 Moreover, VAD treatment could contribute to reverse cardiac remodeling in HF children. 3 Our previous study suggested that VAD heart unloading was able to modify the expression of specific microRNA (miRNAs) in HF pediatric patients.…”

“… 9 In addition to sarcomere proteins, in silico analysis suggested the adiponectin (ADPN) system, including ADPN and its receptors, as a putative target of selected miRNAs ( Figure 1 ). 9 ADPN is an adipocyte-derived protein with the anti-inflammatory, anti-hypertrophic, anti-apoptotic, and anti-fibrotic role in the heart. 10 , 11 , 12 , 13 , 14 , 15 The bond of ADPN to its receptors AdipoR1, AdipoR2, and co-receptor T-cadherin (T-cad) mediates these cardioprotective effects.…”

Myocardial Remodeling with Ventricular Assist Devices

“…Comprehensive microarray profiling of miRNAs and mRNAs, comparing myocardial specimens from adults with end stage HF with VAD and nonfailing hearts, showed upregulation of 28 miRNAs with almost normalization of miRNA profiles by VAD treatment [117]. Cardiac miRNAs have also been compared in 13 HF children at pre-VAD and at the moment of heart transplant (post-VAD) by next-generation sequencing [118]. The investigators found hsa-miR-199b-5p, hsa-miR-19a-3p, and hsa-miR-1246 being differentially expressed at post-VAD compared to that at pre-VAD.…”