title: Simulated microgravity perturbs actin polymerization to promote nitric oxide-associated migration in human immortalized Eahy926 cells.
abstract: Microgravity causes endothelium dysfunctions and vascular endothelium remodeling in astronauts returning from space flight. Cardiovascular deconditioning occurs as a consequence of an adaptive response to microgravity partially due to the effects exerted at cellular level. Directional migration of endothelial cell which are central in maintaining the structural integrity of vascular walls is regulated by chemotactic, haptotactic, and mechanotactic stimuli which are essential for vasculogenesis. We explored the migration property of transformed endothelial cells (EC) exposed to 2-h microgravity, simulated using a three-dimensional clinostat constructed based on blueprint published by the Fokker Space, Netherlands. Migration of EC was measured using the scrap wound healing in the presence or absence of actin polymerization inhibitor-cytochalasin D (CD) in Eahy926 cell lines. Simulated microgravity increased cellular migration by 25% while CD-blocked microgravity induced cellular migration. The key migratory structures of cells, filopodia and lamellipodia, formed by EC were more in simulated microgravity compared to gravity. Parallel experiments with phalloidin and diaminorhodamine-4M (DAR-4M) showed that simulated microgravity caused actin rearrangements that lead to 25% increase in nitric oxide production. Further nitric oxide measurements showed a higher nitric oxide production which was not abrogated by phosphoinositol 3 kinase inhibitor (Wortmanin). Bradykinin, an inducer of nitric oxide, prompted two folds higher nitric oxide production along with simulated microgravity in a synergistic manner. We suggest that limited exposure to simulated microgravity increases Eahy926 cell migration by modulating actin and releasing nitric oxide.
authors.affiliation: Vascular Biology Lab, AU-KBC Research Centre, Anna University, MIT Campus, Chromepet, Chennai, 600044, India.
authors.forename: Jamila H
authors.initials: JH
authors.lastname: Siamwala
authors.forename: S Himabindu
authors.initials: SH
authors.lastname: Reddy
authors.forename: Syamantak
authors.initials: S
authors.lastname: Majumder
authors.forename: Gopi Krishna
authors.initials: GK
authors.lastname: Kolluru
authors.forename: Ajit
authors.initials: A
authors.lastname: Muley
authors.forename: Swaraj
authors.initials: S
authors.lastname: Sinha
authors.forename: Suvro
authors.initials: S
authors.lastname: Chatterjee
mesh_terms: D000199:Actins / Q000378:metabolism*; D000730:Androstadienes / Q000494:pharmacology; D001920:Bradykinin / Q000494:pharmacology; D002460:Cell Line; D002461:Cell Line, Transformed; D002465:Cell Movement / Q000187:drug effects; D022081:Cell Surface Extensions / Q000187:drug effects / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008954:Models, Biological; D018919:Neovascularization, Physiologic / Q000187:drug effects; D009569:Nitric Oxide / Q000096:biosynthesis / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000037:antagonists & inhibitors; D000081082:Phosphoinositide-3 Kinase Inhibitors; D018474:Weightlessness Simulation / Q000295:instrumentation; D000077191:Wortmannin; D014945:Wound Healing / Q000187:drug effects
chemical_list: D000199:Actins; D000730:Androstadienes; D004791:Enzyme Inhibitors; D000081082:Phosphoinositide-3 Kinase Inhibitors; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III; D020928:Mitogen-Activated Protein Kinases; D001920:Bradykinin; D000077191:Wortmannin