Abstract
Homocystinuria is a metabolic disorder caused by a deficiency of cystathionine beta-synthase (CBS). The major clinical symptoms of this disease are mental retardation, lens dislocation, vascular disease with life-threatening thromboembolisms, and skeletal deformities. The major treatments for CBS deficiency include pharmacologic doses of pyridoxine or dietary restriction of methionine. There is currently no effective long-term treatment to lower the elevated plasma levels of homocysteine. However, gene therapy could be an effective novel approach for the treatment of homocystinuria. A recombinant adeno- associated virus vector carrying human CBS cDNA (rAAV-hCBS) was constructed and administered to CBS-/- mice by intramuscular (IM) and intraperitoneal (IP) injections. Serum homocysteine concentrations significantly decreased in treated mice compared with age-matched controls two weeks after treatment. The treated CBS-/- mice had life spans 3-7 days longer compared with untreated CBS-/- mice. In CBS-/- mice treated with rAAV-hCBS via IP injection, the vector was detected in all organs examined including liver, spleen, and kidney, and CBS gene expression was observed by immunohistochemical staining in the liver. These results indicate the efficacy of gene delivery and demonstrate the possibility of gene therapy mediated by AAV gene transfer in this mouse model of homocystinuria.
Highlights
Homocystinuria (MIN 236200) is a metabolic disorder inherited by an autosomal recessive pattern caused by a deficiency of cystathionine -synthase (CBS; EC 4.2.1.22)
The transgene, human CBS (hCBS) cDNA, was driven by a human elongation factor 1- promoter endowed with further stability by the woodchuck hepatitis virus posttranscriptional regulatory element, WPRE, and the polyadenylation site was provided by the BGH polyA
Expression of recombinant adeno-associated virus (rAAV)-hCBS after in vitro transduction Since the cysthathionine -synthase (CBS) gene is not expressed in NIH3T3 cells, these cells were used as a negative control cell line for the in vitro assay
Summary
Homocystinuria (MIN 236200) is a metabolic disorder inherited by an autosomal recessive pattern caused by a deficiency of cystathionine -synthase (CBS; EC 4.2.1.22). CBS is a pyridoxal-5-phosphate-dependent enzyme, which converts homocysteine to cystathionine in the transsulfuration pathway. The structure of the enzyme consists of a catalytic domain of 409 amino acids located in the N-terminal, and a regulatory domain of 142 amino acids located in the C-terminal (Kery et al, 1998; Shan and Kruger, 1998). Deletion of the C-terminal regulatory region, or specific point mutations within this region, can functionally suppress the phenotype of several CBS mutant alleles identified in homocystinuria when expressed in yeast (Shan and Kruger, 1998; Shan et al, 2001)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
