Phospholamban Antisense Oligonucleotides Improve Cardiac Function in Murine Cardiomyopathy

Heart failure (HF) is a major cause of morbidity and mortality worldwide, but therapeutic intervention remains limited despite recent improvements. Aberrant Ca2+ handling is a key feature of HF pathophysiology. Restoring the Ca2+ regulating machinery is an attractive therapeutic strategy supported by genetic and pharmacological proof of concept studies. Here, we studied antisense oligonucleotides (ASOs) as a novel therapeutic modality, interfering with the PLN/SERCA2a interaction by targeting Pln mRNA for downregulation in the heart of murine HF models. Mice harboring the PLN R14del pathogenic variant recapitulate the human dilated cardiomyopathy (DCM) phenotype; subcutaneously administrated PLN-ASO prevented PLN protein aggregation, cardiac dysfunction, and led to a 3-fold increase in survival rate. In another genetic DCM mouse model, unrelated to PLN (as  a disease driver) (Cspr3/Mlp-/-), PLN-ASO also reversed the HF phenotype. Finally, in rats with myocardial infarction, progression of left ventricular dilatation was prevented by PLN-ASO treatment, which also improved left ventricular contractility. Thus, our data establish PLN-ASO as a possible precision medicine for genetic cardiomyopathy as well as general HF. Left ventricle RNA sequencing profiles of 7 week old homozygous Pln R14del mice treated with PBS vs. PLN-ASO and WT mice as control. Additionally, long-term survival data is available for PLN-ASO treated mice.