Cardiac delivery of RNA to treat contractile disorder

The delivery of therapeutic nucleotides to the myocardium is notoriously challenging and remains an important unmet clinical need. Based on the global success of mRNA vaccines, solid lipid nanoparticles are the most widely used vehicle for RNA delivery. We recently identified species of lipid nanoparticles with unprecedented cardiotropism (cLNPs) that are efficient at delivering inhibitory RNA cargos to the heart. This supports development of cLNPs for the therapeutic inhibition of select cardiomyocyte targets. Our prior work suggests that increases in stable, post-translationally detyrosinated microtubules, as mediated by vasohibins (VASH1/2) in complex with their chaperone (SVBP), contribute to contractile dysfunction in human heart failure and clinically relevant animal models. Accordingly, the proposed research tests the hypothesis that cLNPs with inhibitory cargos that limit disease-associated microtubule network detyrosination can improve contractile dysfunction in disease models where increased VASH1 or VASH2 expression has been linked to systolic and/or diastolic dysfunction. To test this hypothesis, Aim 1 experiments will prioritize therapeutic reagents by characterizing the extent and duration of on- and off-target effects of cLNPs with alternative inhibitory cargos (siRNA, shRNA, and antisense oligonucleotides) against both constitutively expressed transcripts or against Vash1, Vash2, or Svbp in healthy rats. Studies demonstrating functional inhibition will be extended to human myocardium using ex vivo delivery of cLNPs to perfused cardiac wedge preparations derived from heart transplant recipients. Aim 2 experiments will determine whether short-term inhibition of Vash2 via delivery of cLNPs is sufficient to blunt contractile dysfunction in viable myocardium following acute myocardial infarction. Aim 3 experiments test whether cLNPs achieving sustained delivery of Vash1 can delay the progression of diastolic dysfunction in an animal model of heart failure with preserved ejection fraction. Our overall study design uses novel and complementary experimental approaches that seek to rigorously characterize inhibitory nucleic acid delivery via cLNPs, and then test them in clinically relevant models of microtubule-dependent cardiac dysfunction. Use of both acute and chronic models of cardiac dysfunction, and in turn acute and chronic therapeutic inhibition, respectively, exploits a range of therapeutic options of cLNPs. Inclusion of delivery to human myocardium furthers ultimate clinical translation. Together this work will establish whether inhibition of microtubule network remodeling is therapeutically beneficial in heart failure, defne which molecular target is best suited for each of two therapeutic scenarios, and establish the versatility of cLNP mediated delivery of inhibitory nucleic acids for the treatment of cardiac dysfunction.