Cardiac-targeted PIASy gene silencing mediates deSUMOylation of caveolin-3 and prevents ischemia/reperfusion-induced Nav1.5 downregulation and ventricular arrhythmias

Abstract

Background Abnormal myocardial Nav1.5 expression and function cause lethal ventricular arrhythmias during myocardial ischemia–reperfusion (I/R). Protein inhibitor of activated STAT Y (PIASy)-mediated caveolin-3 (Cav-3) SUMO modification affects Cav-3 binding to the voltage-gated sodium channel 1.5 (Nav1.5). PIASy activity is increased after myocardial I/R, but it is unclear whether this is attributable to plasma membrane Nav1.5 downregulation and ventricular arrhythmias. Methods Using recombinant adeno-associated virus subtype 9 (AAV9), rat cardiac PIASy was silenced using intraventricular injection of PIASy short hairpin RNA (shRNA). After two weeks, rat hearts were subjected to I/R and electrocardiography was performed to assess malignant arrhythmias. Tissues from peri-infarct areas of the left ventricle were collected for molecular biological measurements. Results PIASy was upregulated by I/R (P < 0.01), with increased SUMO2/3 modification of Cav-3 and reduced membrane Nav1.5 density (P < 0.01). AAV9-PIASy shRNA intraventricular injection into the rat heart downregulated PIASy after I/R, at both mRNA and protein levels (P < 0.05 vs. Scramble-shRNA + I/R group), decreased SUMO-modified Cav-3 levels, enhanced Cav-3 binding to Nav1.5, and prevented I/R-induced decrease of Nav1.5 and Cav-3 co-localization in the intercalated disc and lateral membrane. PIASy silencing in rat hearts reduced I/R-induced fatal arrhythmias, which was reflected by a modest decrease in the duration of ventricular fibrillation (VF; P < 0.05 vs. Scramble-shRNA + I/R group) and a significantly reduced arrhythmia score (P < 0.01 vs. Scramble-shRNA + I/R group). The anti-arrhythmic effects of PIASy silencing were also evidenced by decreased episodes of ventricular tachycardia (VT), sustained VT and VF, especially at the time 5–10 min after ischemia (P < 0.05 vs. Scramble-shRNA + IR group). Using in vitro human embryonic kidney 293 T (HEK293T) cells and isolated adult rat cardiomyocyte models exposed to hypoxia/reoxygenation (H/R), we confirmed that increased PIASy promoted Cav-3 modification by SUMO2/3 and Nav1.5/Cav-3 dissociation after H/R. Mutation of SUMO consensus lysine sites in Cav-3 (K38R or K144R) altered the membrane expression levels of Nav1.5 and Cav-3 before and after H/R in HEK293T cells. Conclusions I/R-induced cardiac PIASy activation increased Cav-3 SUMOylation by SUMO2/3 and dysregulated Nav1.5-related ventricular arrhythmias. Cardiac-targeted PIASy silencing mediated Cav-3 deSUMOylation and partially prevented I/R-induced Nav1.5 downregulation in the plasma membrane of cardiomyocytes, and subsequent ventricular arrhythmias in rats. PIASy was identified as a potential therapeutic target for life-threatening arrhythmias in patients with ischemic heart diseases.

Function and regulation of ubiquitin-like SUMO system in heart

“…PIASy is an important target in diseases such as ischemic heart disease and life-threatening arrhythmias. I/R-induced activation of cardiac PIASy could increase SUMOylation of caveolin-3 (Cav-3) by SUMO2/3, leading to ventricular arrhythmias ( Hu et al, 2022 ). Although the expression of PPARγ is limited in the heart, the ligand-dependent SUMOylation of PPARγ allows its recruitment to the promoters of inflammatory genes to participate in the regulation of these genes ( Zelcer and Tontonoz, 2005 ).…”

A highly sensitive nanochannel device for the detection of SUMO1 peptides

“…† 14,15 The silencing of cardiac-targeted PIASy through the de-SUMOylation of Cav-3 partially prevented the downregulation of the Na v 1.5 protein in the plasma membrane of cardiomyocytes during ischemia/reperfusion injury, thus reducing the incidence of ventricular arrhythmia in rats. 16 TAK-981 selectively reduces SUMOylation, thereby preventing cell proliferation and causing mitotic failure and defective chromosome segregation in pancreatic cancer cells. 17 For telomere maintenance, the disruption of the alternative lengthening of telomere-associated promyelocytic leukemia bodies is a potential target for cancer drugs; this disruption mainly involves SUMOylation.…”