NASA ARC Seminar: Latest Findings: Genomics and Proteomics of Kidney Cells in Space
Note: contact NASA Ames Research Center Office of Public Affairs if you are interested in attending this seminar.
Speaker:
Dr. Timothy Hammond Tulane University Medical Center
12 December 2000
8:30 a.m. to 9:30 a.m.
NASA Ames Research Center Building 233A Room 172
In a Neurolab experiment, we determined which genes mediate three-dimensional culture of cell and tissue aggregates in the low-shear stress, low-turbulent environment of microgravity. Primary cultures of human renal cortical cells were flown on the space shuttle during April 1998. Cells in microgravity and ground-based controls were grown for 6 days and fixed. Flight samples were fixed inflight. RNA was extracted, and automated gene array analysis of the expression of 10,000 genes was performed. A select group of genes were regulated in microgravity. These 1,632 genes were independent of known shear stress response element-dependent genes and heat shock proteins. Specific transcription factors underwent large changes in microgravity including the Wilms’ tumor zinc finger protein, and the vitamin D receptor. A specific group of genes, under the control of defined transcription factors, mediate three-dimensional suspension culture under microgravity conditions.
On STS-106 which launched September 8, 2000, a second examination of kidney cells was undertaken. Postflight analysis revealed some of the mechanisms by which the dynamic culture conditions in space affect cells. Ground controls included aliquots of the same batch of cells spun in a centrifuge to mimic the launch gravity profile. A vibration profile was obtained and rotating wall vessels were used for comparison with statis ground controls. Multiple repeats for gene array were performed, giving us multiple replicates at an early 2 hour time point (Neurolab was 6 days). Other genetic and protein analyses which extended and complimented these gene arrays were completed. Incyte gene arrays measured changes in total binding in known genetic sequences. Affymetrix analysis measured actual specific binding. Ciphergen analysis of nuclear protein allowed us to see known and unknown transcription factors entering the nucleus to turn on the gene cascades. There was sufficient sample to enable limited confocal microscopy of the inflight cells. Analyses still to be performed include Restriction Fragment Differential Display which will reveal known and novel gene sequences and Select Capture of Transcribed Sequences (SCOTS) analysis which can also reveal known and unknown sequences, but more importantly can identify low abundance genes which all the other techniques miss.
The STS-106 experiment was conducted within a single modified Group Activation Pack (GAP) of Bioserve’s Commercial Generic Bioprocessing Apparatus (CGBA). Each GAP encloses a volume of approximately 0.75 liter and provides temperature control and automated inflight fixation capabilities. The CGBA nominally contains 8 GAPs, each with individual temperature and fixation options, and fits within a Space Shuttle middeck locker.
This seminar will present the latest findings from STS-106 as well as the Neurolab results.
Dr. Timothy Hammond is Director of the Tulane Environmental Astrobiology Center at the Tulane University Medical Center, Associate Chief of Staff for Research at the New Orleans VA Medical Center, and Associate Professor Nephrology Section, Tulane University Medical Center. He is board certified in Internal Medicine and Nephrology. Dr. Hammond received a B.Med.Sci &M.B., B.S. from the University of Melbourne Medical School, Melbourne, Australia. He interned at the Royal Melbourne Hospital and served his residency in Internal Medicine at University of Wisconsin-Milwaukee Clinical Campus. Dr. Hammond was a Research Fellow in the Department of Physiology, Harvard Medical School; J.G. Hunter Fellow at the Australian Medical Association, Royal Melbourne Hospital; Research Fellow at the Department of Physiology and Biophysics at the Mayo Clinic and Clinical Nephrology Fellow at the University of Wisconsin, Madison & Milwaukee Clinical Campuses.
Background Information
