Date of Award

2009

Degree Name

Biological Sciences

College

College of Science

Type of Degree

M.S.

Document Type

Thesis

First Advisor

Elmer M. Price

Second Advisor

David S. Mallory

Third Advisor

Brian L. Antonsen

Abstract

Stem cells are populations of undifferentiated cells that are found in most tissues and act as precursors for regeneration and maintenance. In the future, they could provide promising therapies for diseases which are to date incurable. Our lab developed a novel cell line from the peripheral blood of adult transgenic green fluorescent protein swine and designated them as Peripheral Blood Derived Multipotent Adult Progenitor Cells (PBD-MAPCs). In this study we characterized the mRNA and protein expression profiles of PBD-MAPCs before and after neural differentiation and investigated the potential of PBD-MAPCs to differentiate into myocardial or neural lineages in vitro. We examined the potential of various cytokines to differentiate PBDMAPCs into cardiomyocytes. Also, as an alternative approach, we co-cultured PBD-MAPCs with neonatal cardiomyocytes or embryonic cardiomyoblasts, which produce factors to induce stem cell differentiation. These experiments did not succeed in differentiating PBD-MAPCs to a cardiac lineage. To study the expression profile of PBD-MAPCs before and after neural differentiation, we probed for the expression of stem cell marker CD133 in undifferentiated PBD-MAPCs and neural markers tyrosine hydroxylase (TH), β-tubulin III and PGP9.5 in neurally differentiated PBD-MAPCs using reverse transcription-PCR (RT-PCR) and immunoblot assays. Undifferentiated PBD-MAPCs were found to express CD133 and the neural markers TH, β-tubulin III and PGP9.5. Upon differentiation, they lost expression of CD133, TH and PGP9.5. Finally, we performed 3 dimensional cell cultures on PBD-MAPCs using various biomaterials in iiineural differentiation medium. We also tested if muscle fibers added to the biomatrix provide directional support to the growing cellular processes. This 3 dimensional cell culture research is a preliminary study aimed at the development of a bridging transplant for spinal cord injuries. On differentiation, cells showed neural morphology with long cellular processes and were immunopositive for neural proteins. Cells also grew along the muscle fibers indicating that muscle fibers provide support to the growing cells. Taken together, these data suggest that PBDMAPCs are stem cells and can be a promising stem cell population for future research in cellular therapeutics for spinal cord injury.

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