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Proteomic Retrieval From Nucleic Acid Depleted Space-Flown Human Cells. D.K. Hammond1, T.F. Elliott3, K. Holubec3, T.L. Baker3, P.L. Allen4,5 T.G. Hammond4,5  and J.E. Love2.  1EASI; 2HACO, NASA, Johnson Space Center; and  3Wyle Life Sciences, Houston;  4V.A. Medical Center and 5Tulane University Health Sciences Center, New Orleans.

When compared to experiments utilizing humans in microgravity, cell-based approaches to questions about subsystems of the human system afford multiple advantages, such as crew safety and the ability to achieve statistical significance.  To maximize the science return from flight samples, an optimized method was developed to recover protein from samples depleted of nucleic acid. Specimens treated with an RNA stabilizing agent enabled both RNA and immunoreactive protein analysis. Human renal cortical epithelial (HRCE) cells grown onboard the International Space Station (ISS) during Increment 3 and ground control cultures exhibited similar immunoreactivity profiles for antibodies to the Vitamin D receptor (VDR), the beta isoform of protein kinase C (PKCß) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Parallel immunohistochemical studies on formalin-fixed flight and ground control cultures also showed positive immunostaining for VDR and other biomarkers.  These results are consistent with data from additional antigenic recovery experiments performed on human Mullerian tumor cells cultured in microgravity. This technique allows multiple analyses on a single cellular sample and when applied to future cellular bioastronautics investigations could accelerate solutions to significant biomedical  barriers to human space exploration.  (Supported by NAS9-02078 and NRA grant #NAG8-1362).