title: Mechanical culture conditions effect gene expression: gravity-induced changes on the space shuttle.
abstract: Three-dimensional suspension culture is a gravity-limited phenomenon. The balancing forces necessary to keep the aggregates in suspension increase directly with aggregate size. This leads to a self-propagating cycle of cell damage by balancing forces. Cell culture in microgravity avoids this trade-off. We determined which genes mediate three-dimensional culture of cell and tissue aggregates in the low-shear stress, low-turbulent environment of actual microgravity. Primary cultures of human renal cortical cells were flown on the space shuttle. Cells grown in microgravity and ground-based controls were grown for 6 days and fixed. 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.
authors.affiliation: Nephrology Section, Department of Medicine, Tulane/Veterans Affairs Environmental Astrobiology Center, New Orleans, Louisiana 70112, USA. thammond@mailhost.tcs.tulane.edu
authors.forename: T G
authors.initials: TG
authors.lastname: Hammond
authors.forename: E
authors.initials: E
authors.lastname: Benes
authors.forename: K C
authors.initials: KC
authors.lastname: O'Reilly
authors.forename: D A
authors.initials: DA
authors.lastname: Wolf
authors.forename: R M
authors.initials: RM
authors.lastname: Linnehan
authors.forename: A
authors.initials: A
authors.lastname: Taher
authors.forename: J H
authors.initials: JH
authors.lastname: Kaysen
authors.forename: P L
authors.initials: PL
authors.lastname: Allen
authors.forename: T J
authors.initials: TJ
authors.lastname: Goodwin
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D018929:Cell Culture Techniques / Q000379:methods*; D002478:Cells, Cultured; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D005796:Genes / Q000235:genetics; D006112:Gravitation; D006801:Humans; D007668:Kidney / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D012313:RNA / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013026:Space Flight
chemical_list: D012313:RNA