Urocortin Gene Transfer for CHF a Paracrine Approach Using Intravenous AAV

DESCRIPTION provided by applicant Gene transfer for the treatment of cardiovascular diseases is bedeviled by inability to obtain safely and easily sufficient cardiac transgene expression Current methods of gene transfer for heart disease include intramuscular injection into heart muscle or intracoronary delivery approaches that are cumbersome to apply Consequently we have considered the usefulness of a vector encoding a paracrine type transgene In this approach the transgene acts as a hormone having cardiac effects after being released to the circulation from a distant site This approach would circumvent the problem of attaining high yield cardiac gene transfer and enable patients to be treated by a systemic injection during an office visit Furthermore the approach proposed would eliminate the need for intravenous delivery of therapeutic peptides and thereby circumvent repeated and prolonged hospital stays high morbidity and enormous economic costs The most suited vector to achieve these goals is the adeno associated virus type AAV which provides long term and extensive expression after intravenous delivery in rodents pigs and primates Urocortin a recently discovered corticotrophin releasing factor family vasoactive peptide acts via corticotropin releasing factor type receptors which are robustly expressed in the heart and vasculature Studies in animals and patients with congestive heart failure have shown favorable hemodynamic effects of urocortin peptide infusions including increased contractile function independent of loading indicating direct cardiac effects Urocortin is an ideal selection as a therapeutic transgene in the proposed studies We have established that intravenous delivery of AAV using the chicken actin promoter provides sustained high serum levels of UCn and increases function of the normal and failing mouse heart To develop and refine such an approach we propose to determine in sequential studies in mice and pigs a the optimal system to provide regulated transgene expression to enable fine tuning of plasma transgene levels and allow turning expression off and on as needed and b the safety and efficacy of urocortin gene transfer using this optimal paracrine based approach in a mouse model of CHF Subsequently in normal pigs we will determine a the minimally effective vector dose required to increase serum urocortin b biodistribution of the vector and transgene and c toxicity HYPOTHESIS Intravenous injection of an AAV vector with regulated expression of urocortin will through paracrine mediated actions have favorable effects on the failing heart Aim To determine the optimal regulated expression system to achieve long term and dose responsive urocortin expression in plasma with minimal immune response and toxicity Aim To test the optimal AAV vector providing regulated expression of urocortin identified in Aim and determine in mice with and without heart failure a plasma levels over months b efficacy for increasing function of the failing heart and reducing mortality c mechanisms for beneficial effects and d biodistribution and toxicity of the vector and transgene Aim To test the optimal AAV vector encoding urocortin confirmed in Aim in normal pigs to determine a plasma levels of urocortin b biodistribution of the vector and transgene c toxicity These mechanistic and proof of concept studies are designed to be sufficient in scope to lay the groundwork for future studies to be conducted in a CHF model in pigs and subsequently file an IND to initiate a clinical trial PUBLIC HEALTH RELEVANCE We propose to develop a method to treat patients with heart failure using an intravenous injection of a gene therapy virus vector encoding a peptide that improves heart function The peptide is called urocortin and it has favorable effects on the heart and blood vessels In preclinical studies this approach increases function of the failing heart in mice