Development of novel heart failure therapy by using gene transfer into cardiac myocytes

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1) Development of novel heart failure therapy by introducing SERCA2 gene into cardiac myocytesWe have developed gene transfer system bearing human SERCA2 cDNA using adeno-associated virus and lenti-virus. By infecting these constructs into cardiac myocytes, we observed 3-fold increase of SERCA2 mRNA and 2-fold of SERCA2 protein. In the transfected myocytes, Ca2+ uptake capacity was enhanced by 40% in compared with the group infected with control vector that did not harbor SERCA2 cDNA. We are now under investigation of the effect of the gene transfer on the in vivo cardiac function in the rat.2) Development of heart failure therapy by inhibiting the phospholamban expression using a RNA interference methodPhospholamban is a key regulatory protein for Ca2+ uptake function of SERCA2 protein. Inibition of phospholamban increases the Ca2+ uptake function. In this research project, we have developed phospholamban-specific RNA interference method. Double strand 21 ribonucleotide sequence specific for coding region of phospholamban gene was introduced into rat neonatal cardiac myocytes using HVJ envelope. The effect of phospholamban siRNA was highly gene specific for target mRNA and reduced its mRNA level to 10% of control group. The anount of phospholamban protein was also significantly decresed to 10% of control. Importantly, Ca2+ uptake kinetics was shifted to increase the efficiency by 38%. These beneficial effect of phospholamban RNAi was also demonstrated in the hydrogen peroxide-induced failing heart model. Decreased Ca2+ uptake was restored in the phospholamban ablation group.Our data suggest that genetic modulation of Ca2+ transporting protein has a therapeutic benefit in the treatment of heart failure.