Abstract

The prevalence of type 2 diabetes has been steadily increasing around the globe. Glucagon like peptide (GLP-1), a powerful incretin increases insulin secretion in a glucose dependent manner. But GLP-1 is subjected to rapid enzymatic degradation (half-life: 2 min in circulation). The commercially available GLP-1 analog, exenatide has a longer half life with potent insulinotropic effects (about 2.4 hr) which requires cold storage and daily subcutaneous injections. In this study, exendin 4 (EX4), lizard derived GLP-1R agonist, was expressed as cholera toxin B subunit (CTB)-fusion protein in chloroplasts of tobacco to facilitate transmucosal delivery in the gut by utilizing the ability of CTB pentamer to bind the GM1 receptors on the intestinal epithelium and to bioencapsulate EX4 within plant cells to confer protection in the digestive system. The LAMD tobacco leaves were bombarded with chloroplast vectors expressing modified EX4. The transgene integration was confirmed by PCR analysis and Southern blot analysis. Densitometric analysis revealed expression level of the protein varied from 9-13% of the total leaf protein depending on the developmental stage and time of harvest. The pentameric structure and functionality of CTB-EX4 fusion protein was confirmed by CTB-GM1 binding assay. The effect of transplastomic protein on insulin secretion was tested in β-TC6, a mouse pancreatic cell line. The plant derived CTB-EX4, partially purified with anti-CTB antibody conjugated protein A beads, showed the increase of insulin ~ 2.5 fold increase when compared to untreated cells. The transplastomic protein showed a linear increase in insulin secretion comparable to the commercially available EX4. The current cost of treatment with EX4 varies between $1800-$2200, annually. Production of functional EX4 in plants should facilitate low cost orally deliverable form of this drug for treatment of type 2 diabetes.

Notes

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Graduation Date

2011

Semester

Fall

Advisor

Daniell, Henry

Degree

Master of Science (M.S.)

College

College of Medicine

Department

Molecular Biology and Microbiology

Degree Program

Biotechnology

Format

application/pdf

Identifier

CFE0004485

URL

http://purl.fcla.edu/fcla/etd/CFE0004485

Language

English

Release Date

June 2013

Length of Campus-only Access

1 year

Access Status

Masters Thesis (Open Access)

Subjects

Dissertations, Academic -- Medicine, Medicine -- Dissertations, Academic

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