miR-221 and -222 target CACNA1C and KCNJ5 leading to altered cardiac ion channel expression and current density

Abstract

MicroRNAs (miRs) contribute to different aspects of cardiovascular pathology, among others cardiac hypertrophy and atrial fibrillation. The aim of our study was to evaluate the impact of miR-221/222 on cardiac electrical remodeling. Cardiac miR expression was analyzed in a mouse model with altered electrocardiography parameters and severe heart hypertrophy. Next generation sequencing revealed 14 differentially expressed miRs in hypertrophic hearts, with miR-221 and-222 being the strongest regulated miR-cluster. This increase was restricted to cardiomyocytes and not observed in cardiac fibroblasts. Additionally, we evaluated the change of miR-221/222 in vivo in two models of pharmacologically induced heart hypertrophy (angiotensin II, isoprenaline), thereby demonstrating a stimulus-induced increase in miR-221/222 in vivo by angiotensin II but not by isoprenaline. Whole transcriptome analysis by RNA-seq and qRT-PCR validation revealed an enriched number of downregulated mRNAs coding for proteins located in the T-tubule, which are also predicted targets for miR-221/222. Among those, mRNAs were the L-type Ca 2+ channel subunits as well as potassium channel subunits. We confirmed that both miRs target the 3′-untranslated regions of Cacna1c and Kcnj5. Furthermore, enhanced expression of these miRs reduced L-type Ca 2+ channel and Kcnj5 channel abundance and function, which was analyzed by whole-cell patch clamp recordings or Western blot and flux measurements, respectively. miR-221 and-222 contribute to the regulation of L-type Ca 2+ channels as well as Kcnj5 channels and, therefore, potentially contribute to disturbed cardiac excitation generation and propagation. Future studies will have to evaluate the pathophysiological and clinical relevance of aberrant miR-221/222 expression for electrical remodeling. Keywords Electrical remodeling • Cardiomyocytes • Angiotensin II • Heart hypertrophy Abbreviations ANOVA Analysis of variance AUC Area under the curve AII Angiotensin II Bp Base pair BW Body weight Cacna1C Calcium voltage-gated channel subunit α1 C, L-type Cacnb2 Calcium voltage-gated channel auxiliary subunit β2 Cacna2d1 Voltage-dependent calcium channel subunit α2/δ1 Cav1.2 L-type Ca 2+ channel CCH Carbachol, acetylcholine analog cDNA Complementary DNA CE Carbachol effect CM Cardiomyocyte ddPCR Droplet digital PCR Cellular and Molecular Life Sciences

Exosomal LncRNA–NEAT1 derived from MIF-treated mesenchymal stem cells protected against doxorubicin-induced cardiac senescence through sponging miR-221-3p

“…Mir-221-3p was notably activated in the age-related degeneration diseases [48]. MiR-221-3p is enriched in aged cardiac tissue, thus leading to age-related cardiac injury [49]. Dox induced cardiac senescence accompanied by elevated levels of miR-221-3p in the cardiac tissue, while this elevation of miR-221-3p was reversed by exosomes MIF , through transferring LncRNA-NEAT1.…”

Exosomal LncRNA–NEAT1 Derived From MIF-Treated Mesenchymal Stem Cells Protected Against Doxorubicin-induced Cardiac Senescence Through Sponging miR-221-3p

“…Mir-221-3p was notably activated in the age-related degeneration diseases [39]. MiR-221-3p is enriched in aged cardiac tissue, thus leading to age-related cardiac injury [40]. Dox induced cardiac senescence accompanied by elevated levels of miR-221-3p in the cardiac tissue, while this elevation of miR-221-3p was reversed by exosomes MIF , through transferring LncRNA-NEAT1.…”

Molecular Mechanisms, Diagnostic Aspects and Therapeutic Opportunities of Micro Ribonucleic Acids in Atrial Fibrillation

“…Atrial electrical remodeling (AER) refers the shortening of atrial action potential duration (APD), refractory period and the decrease of atrial conduction velocity [46]. The ion channels that influence action potential generation, duration and propagation are the L-type Ca 2+ channel (Cav1.2), the voltage-gated potassium channel Kv4.2 or the G-protein-activated inwardly rectifying potassium channel (GIRK1/4) [47]. AF may be triggered due to premature pulmonary vein discharges, rapid electrical stimulation of atria, or a simple wave break.…”

“…It is now accepted that some miRNAs are associated with AER. Binas et al [47] evaluated the impact of miR-221/222 on cardiac electrical remodeling. Cardiac miRNA expression was analyzed in a mouse model with altered electrocardiography parameters and severe heart hypertrophy.…”

“…They found out that increased miR-221/222 levels are associated with certain forms of hypertrophy mediated by upregulation of renin-angiotensin-aldosterone system. Another important finding is that alteration of miR-221/222 expression is associated with changed Cav1.2 and GIRK1/4 channel density resulting in slower propagation of action potential and possibly disturbed electromechanical coupling, thereby making the heart more vulnerable to arrhythmia, what is manifested on electrocardiogram (ECG) as a prolonged QT interval [47].…”