192. Regulated Atrial Natriuretic Peptide Expression with a Novel Spatiotemporal AAV Vector Cassette for Treating Congestive Heart Failure

Patients suffering from congestive heart failure (CHF) are vulnerable to a fluid overloaded state, contributing to significant morbidity and the mortality of ~287,000 patients per year in the US. This vulnerability is in part mediated by a dysregulation of atrial natriuretic peptide (ANP) – a molecule acting on kidneys to induce diuresis. Multiple preclinical studies show that injecting pre-synthesized ANPs can induce diuresis, however pre-synthesized ANPs degrade rapidly making their impact only transient. Sustained ANP-mediated diuresis may provide a novel approach to curb fluid retention. To this end, we hypothesize that the use of AAV9 vectors will mediate delivery of a more biologically active version of ANP (aka mANP) in the context of a cardiomyocyte-specific, tetracycline-regulated expression cassette. Methodology – For temporal regulation we inserted a Tet-On 3G System into an AAV cassette (AAV-Tet). For cardiac restricted expression we also introduced a cardiomyocyte specific regulatory element. Preliminary Data – Doxycycline specifically induces expression in vitro of all tested genes, i.e. mANP, EGFP, and firefly luciferase (Luc). Regulation is tight, showing Luc expression increases of ~2000-fold over baseline. Using murine models we are currently accessing the pharmacokinetics of the AAV9-Tet vectors. Finally, diuretic potentials will be assessed in murine models of CHF. Conclusion – The spatiotemporally regulated mANP AAV vectors being developed herein could represent a new paradigm for treatment in CHF.