Rescue of multiorgan pathophysiology by adeno-associated virus 1 gene therapy

点击翻译按钮获取中文摘要

AAV vectors have great potential as gene therapeutic agents (3-5), in particular for cystic fibrosis (CF). Studies originating from our group led to the first use of rAAV in humans (2). Many studies have shown that AAV vectors can be used safely (5,6,9). The major challenge, however, is that they have not achieved a reproducible thera- peutic effect, making it necessary to take a new approach to AAV gene therapy. In previous work, we have identified three new strategies to alleviate these problems: 1) the use of AAV1, which is more tropic for the lung; 2) the use of 27-264, a truncated version of CFTR that corrects ∆F508 by a novel mechanism; and 3) the inclu- sion of a powerful chicken β-actin (CBA) promoter. Given that CF is a multi-organ disease, a gene-based therapy will have to target several organs whose cells normally turn over (3,4), making it advantageous to employ a virus that can transduce multiple cell types if it is to be used in a single-treatment therapy. To further explore this approach, we will use a ferret model bearing the G551D mutation, which responds to the CF potentiator VX-770. We propose three overall Specific Aims: Aim 1: To evaluate systemic vs. airway delivery of AAV1 gene therapy to transduce organs affected by CF. For gene therapy to be effective for CF, it must correct defective CFTR function in several organs in the body besides the airways. The question addressed here is whether transduction can occur in peripheral organs following airway delivery of naturally occurring AAV1. Aim 2: To determine the duration of the therapeutic effects of AAV1 vectors containing truncated CFTR. The overarching questions for CF gene therapy are whether gene transduction can rescue the CF phenotype and how long the therapeutic effect will last before a repeated dose is necessary. The answers to these practical questions have enormous clinical consequences for the development of effective CF gene therapy. This Aim will address the extent to which AAV1 vectors containing either AAV1-CBΔ27-264 or ΔR-CFTR will be effective in rescuing the CF phenotype and how long the rescue will last following a single dose of AAV. Aim 3: To determine whether dosing with an AAV1 vector con- taining a truncated CFTR will lead to transduction in the ferret GI tract and human enteroids. Given that gene therapy for CF will have to target multiple organs, the goal here is to show that AAV1-derived vectors will transduce the GI tract. For this Aim, we will take a two-pronged approach: First, from the ferrets transduced in Aims 1 and 2, we will isolate sections of GI tract (ileum and colon) and measure the transport characteristics of the transduced, excised tissue. Second, given that the ultimate goal of our studies is to treat patients with CF, we will study to what extent AAV1 virus containing truncated CFTR will rescue human enteroids from patients with mutations that are hard to treat with current therapies. Significance: CF is an autosomal disease that leads to significant morbidity and mortality in patients with the disorder (9). This work is novel because it proposes to treat the multiorgan pathologies associated with CF.