Gene Transfer Therapy for Alport Syndrome

描述(由申请人提供)：这项提议的长期目标是开发人类Alport综合征的基因转移疗法，这是一种遗传性肾脏疾病，目前肾脏移植是唯一的治疗方法。这种疾病是由IV型胶原基因突变引起的，IV型胶原是被称为基底膜的组织结构的组成部分。肾小球基底膜(GBM)缺乏正常的IV型胶原，导致肾小球基底膜(GBM)退化，导致肾功能不全。这一建议的中心假设是，通过将缺陷的IV型胶原的正确拷贝转移到合成GBM蛋白的肾小球细胞中，可以充分恢复GBM的正常IV型胶原成分，从而稳定GBM的结构，减缓或阻止Alport肾病的进展。在X连锁Alport综合征中，编码IV型胶原a5链的基因(Col4A5)发生突变。这项应用的目的是使用一种实现基因转移到肾小球细胞的新方法来治疗X-连锁机场综合征(XLAS)。该建议的具体目的是：(1)使用由开放手术技术输送的病毒载体进行闭路肾脏灌流，该载体成功地将编码C5型IV型胶原的cDNA转移到正常猪的肾小球内，以治疗XLAS犬；(2)构建包含全长Col4A5 cDNA的新病毒载体，使转基因基因能够稳定表达长达一年；(3)开发使用经血管插管技术进行闭路肾脏灌流的微创方法，以允许个别受试者重复治疗；以及(4)在狗身上进行XLAS基因转移治疗的随机试验。转基因E5(IV)链的表达对Alport GBM的分子、结构和功能特性以及对Alport肾病临床病程的影响将被确定。女性XLAS杂合子表现出的轻度肾病表型表明，即使在男性半合子中实现Normal_5(IV)链的嵌合体表达，也将产生临床满意的治疗结果。由于犬XLAS是人类Alport综合征的动物模型，因此在狗身上成功地进行XLAS的基因转移治疗将为在人类身上试验这种治疗Alport综合征的方法提供基础。这也为其他肾小球疾病的基因转移治疗奠定了基础。

DESCRIPTION (provided by applicant): The long-range goal of this proposal is development of gene transfer therapy for human Alport syndrome, a genetic renal disease for which kidney transplantation currently is the only treatment. The disease results from mutations in genes for type IV collagen, which is an integral component of tissue structures known as basement membranes. Abnormalities leading to renal failure are initiated by deterioration of the glomerular basement membrane (GBM) that occurs because of an absence of normal type IV collagen in the GBM. The central hypothesis of this proposal is that the normal type IV collagen composition of the GBM can be adequately restored by transferring a correct copy of the defective gone into the glomerular cells that synthesize GBM proteins, thus stabilizing GBM structure and slowing or stopping progression of Alport renal disease. In X-linked Alport syndrome, the gene (COL4A5) that encodes the a5 chain of type IV collagen is mutated. The objective of this application is to use a new method of achieving gene transfer into glomerular cells to treat dogs with X-linked Aiport syndrome (XLAS). Specific aims of the proposal are to: (1) use a virus vector delivered by an open surgical technique for closed-circuit renal perfusion that successfully transferred a cDNA encoding c_5type IV collagen into the glomeruli of normal pigs to treat dogs with XLAS, (2) construct new viral vectors containing full-length COL4A5 cDNAs that will enable stable transgene expression for up to one year, (3) develop minimally invasive methods for performing closed circuit perfusion of the kidney using trans-vascular catheterization techniques to permit repeated treatment of individual subjects, and (4) perform randomized trials of gene transfer therapy for XLAS in dogs. Effects of transgenic E5(IV) chain expression on the molecular, structural and functional properties of Alport GBM and on the clinical course of Alport renal disease will be determined. The mild renal disease phenotype manifested in female heterozygotes with XLAS suggests that even achieving mosaic expression of normal _5(IV) chains in male hemizygotes will produce a clinically satisfactory treatment result. Because canine XLAS is an animal model of human Alport syndrome, successful gene transfer therapy for XLAS in dogs will provide a basis for trials of such treatment for Alport syndrome in people. It will also lay the foundation for gene transfer therapy of other glomerular iseases.