rAAV‐asPLB transfer attenuates abnormal sarcoplasmic reticulum Ca²⁺‐ATPase activity and cardiac dysfunction in rats with myocardial infarction

Abstract

Background: Diminished myocardial sarcoplasmic reticulum Ca 2+ -ATPase (SERCA) activity and upregulated phospholamban (PLB) level during cardiac dysfunction, had been reported in many studies. Aims: The current study was designed to examine the effects of rAAV-antisense phospholamban (asPLB) gene transfer on cardiac function, SERCA expression and activity, as well as PLB expression and phosphorylation (Pser16-PLB), in a rat myocardial infarction (MI) model. Methods and results: Rat MI model was generated by ligating the left anterior descending coronary artery. Four weeks later, left ventricular ejection fraction (LVEF), left ventricular systolic pressure (LVSP), the maximal rates of increase and decrease in intraventricular pressure (± dp / dt max ) were significantly depressed, and left ventricular end diastolic pressure (LVEDP) was increased. Myocardial PLB was markedly increased while both SERCA activity and Pser16-PLB level were decreased. In rAAV-asPLB transfected rats, rAAV-asPLB, which was injected into the myocardium around the infarction area immediately after the coronary artery ligation, effectively attenuated the depression of cardiac function, significantly inhibited the expression of PLB, restored Pser16-PLB level and enhanced myocardium SERCA activity. Conclusion: rAAV-asPLB transfer in rats with MI effectively prevented the progression of heart failure.

Cardiac Gene Transfer of Short Hairpin RNA Directed Against Phospholamban Effectively Knocks Down Gene Expression but Causes Cellular Toxicity in Canines

“…Although PLB knockout mice exhibit enhanced contractility without evidence of cardiomyopathy (Slack et al, 2001), and PLB inhibition in hamsters (Hoshijima et al, 2002) and rats (Iwanaga et al, 2004;Sakata et al, 2007;Zhao et al, 2008;Suckau et al, 2009) is effective in suppressing the progression of HF, humans homozygous and heterozygous for a null PLB L39Stop mutation develop left ventricular hypertrophy, premature dilated cardiomyopathy, and HF (Haghighi et al, 2003). This discrepancy in phenotype may exist because …”

Adeno-Associated Virus Vectors as Therapeutic and Investigational Tools in the Cardiovascular System

“…115 Accordingly, the AAVmediated knockdown of phospholamban by 3 different strategies, namely RNA interference, antisense oligonucleotides, and engineered zinc-finger protein transcription factor, was effective in restoring cardiac function and geometry in rat models of heart failure. 69,116,117 The enthusiasm for these promising results has been recently lessened by a study in which an shRNA against phospholamban delivered by an scAAV6 vector in canines resulted in serum troponin elevation and depressed cardiac function, possibly attributed to the dysregulation of endogenous microRNA pathways. 53 AAV-based experiments have proven the important role of additional proteins in controlling the levels of functional SERCA2a.…”

microRNA‐132 inhibits cardiomyocyte apoptosis and myocardial remodeling in myocardial infarction by targeting IL‐1β

“…EdU, 5-ethynyl-2'-deoxyuridine; H&E, Hematoxylin and eosin; IL-1β, interleukin-1β; MI, myocardial infarction; miR, microRNA; RT-qPCR, reverse-transcription quantitative polymerase chain reaction; TTC, 2, 3, 5-triphenyl tetrazolium chloride; TUNEL, terminal-deoxynucleoitidyl transferase mediated nick-end labeling can indicate cardiac dysfunction (Song et al, 2014). Zhao et al (2008) have also confirmed that LVEF and ±dp/dt max are decreased in MI rat models, suggesting that MI is typically accompanied with cardiac dysfunction. Bcl-2, antiapoptotic element, and Bax, proapoptotic element, which both function upstream of Caspase-3 in the apoptotic pathways, are critical regulatory factors during the process of cell death (Lim, Kim, & Lee, 2014).…”