All ETDs from UAB

Advisory Committee Chair

David M Bedwell

Advisory Committee Members

Jerry N Thompson

Kim M Keeling

Robert A Kesterson

Trenton R Schoeb

Document Type

Dissertation

Date of Award

2012

Degree Name by School

Doctor of Philosophy (PhD) Heersink School of Medicine

Abstract

Nonsense suppression therapy utilizes compounds that suppress translation termination at disease-causing premature termination codons (PTCs) to restore full-length, functional protein synthesis. This approach may provide a treatment for many diseases caused by nonsense mutations including Hurler syndrome (mucopolysaccharidosis type I - Hurler, MPS I-H). MPS I-H is a lysosomal storage disease caused by severe &alpha-L-iduronidase deficiency and subsequent lysosomal glycosaminoglycan (GAG) accumulation. In this work, we investigated the effectiveness of nonsense suppression therapy as a treatment for MPS I-H. We first generated a targeted knock-in mouse model that carries the Idua-W392X nonsense mutation homologous to the human IDUA-W402X mutation frequently found in MPS I-H patients. The homozygous Idua-W392X mice exhibit phenotypes that are consistent with the biochemical defects and disease manifestations in human MPS I-H patients, including a deficiency of α-L-iduronidase activity and elevated GAG levels in urine and tissues. As a result, the Idua-W392X mouse represents a murine model of human MPS I-H, and it is suitable to study suppression therapy in vivo. We next tested a broad range of known suppression agents, including the conventional aminoglycosides gentamicin, G418, amikacin, and paromomycin, as well as two novel synthetic aminoglycosides NB54 and NB84 that were designed for better readthrough efficiency and reduced toxicity. We found that NB84 treatment significantly improved the primary biochemical defects associated with MPS I-H in vitro and in vivo, suggesting that NB84-mediated suppression therapy has the potential to attenuate the MPS I-H disease phenotype. Overall, we demonstrated the feasibility of suppressing a nonsense mutation underlying Hurler syndrome by stimulating translational readthrough at the corresponding PTC in vivo. Our results suggested that suppression therapy is a potential treatment for Hurler syndrome. The Idua-W392X mouse model we generated and characterized in this study proved to be a suitable in vivo system to test novel suppression agents and potentially other treatment approaches to enhance the efficacy of suppression therapy, such as NMD inhibition.

Share

COinS