Abstract
Abstract: :
Purpose:To perform a proteomic analysis comparing retinal progenitor cells with brain progenitor cells. Different populations of stem cells and progenitor cells are likely to possess unique molecular fingerprints that may be correlated with their ability to survive, differentiate and integrate after transplantation. By characterizing the molecular fingerprint of cells that give the most promising results, we may be able to begin to identify the fundamental protein expression requirements for a given transplant application. We are using two–dimensional gel electrophoresis to characterize the proteome of two populations of progenitor cells (brain progenitor cells; BPCs, and retinal progenitor cells RPCs) isolated from mice of the same age and genetic background. Methods: RPCs and BPCs used in this study were isolated and expanded in vitro from neonatal mice as reported previously (Shatos et al., J. Reg. Med.(2), 2001). The cells were maintained as neurospheres in supplemented neurobasal medium with 20 ng/mL EGF. Cells were sonicated in hypotonic buffer with protease inhibitors and centrifuged to remove nuclei. 35 µg of protein was focused using pH 3–10 7.7cm IEF strips and separated in the second dimension on 4–12% Bis–Tris gels. Gels were stained with Sypro Ruby and analyzed for significant changes in the intensity of protein spots using Phoretix Expression 2D software. Results: Our analysis has thus far identified 323 distinct protein spots on the RPC gels and 233 distinct spots on the BPC gels. Of the proteins present in samples from both RPCs and BPCs, expression was greater (at least 2–fold) at 14 spots and lesser (at least 2–fold) at 32 spots in BPCs compared to RPCs. Conclusions: In our analysis comparing progenitor cells from the retina and brain demonstrates significant differences in 136 distinct protein spots. These results demonstrate the utility of proteomics for characterization of different progenitor cell populations in an effort to gain a better understanding of their fundamental, molecular similarities and differences. Ultimately, these molecular differences may be used to target different populations of cells for the most appropriate therapeutic applications.
Keywords: retinal development • proteomics