title: Simulated Microgravity Modulates Differentiation Processes of Embryonic Stem Cells.
abstract: OBJECTIVE
  Embryonic developmental studies under microgravity conditions in space are very limited. To study the effects of altered gravity on the embryonic development processes we established an in vitro methodology allowing differentiation of mouse embryonic stem cells (mESCs) under simulated microgravity within a fast-rotating clinostat (clinorotation) and capture of microarray-based gene signatures.
  
  
  METHODS
  The differentiating mESCs were cultured in a 2D pipette clinostat. The microarray and bioinformatics tools were used to capture genes that are deregulated by simulated microgravity and their impact on developmental biological processes.
  
  
  RESULTS
  The data analysis demonstrated that differentiation of mESCs in pipettes for 3 days resultet to early germ layer differentiation and then to the different somatic cell types after further 7 days of differentiation in the Petri dishes. Clinorotation influences differentiation as well as non-differentiation related biological processes like cytoskeleton related 19 genes were modulated. Notably, simulated microgravity deregulated genes Cyr61, Thbs1, Parva, Dhrs3, Jun, Tpm1, Fzd2 and Dll1 are involved in heart morphogenesis as an acute response on day 3. If the stem cells were further cultivated under normal gravity conditions (1 g) after clinorotation, the expression of cardiomyocytes specific genes such as Tnnt2, Rbp4, Tnni1, Csrp3, Nppb and Mybpc3 on day 10 was inhibited. This correlated well with a decreasing beating activity of the 10-days old embryoid bodies (EBs). Finally, we captured Gadd45g, Jun, Thbs1, Cyr61and Dll1 genes whose expressions were modulated by simulated microgravity and by real microgravity in various reported studies. Simulated microgravity also deregulated genes belonging to the MAP kinase and focal dhesion signal transduction pathways.
  
  
  CONCLUSIONS
  One of the most prominent biological processes affected by simulated microgravity was the process of cardiomyogenesis. The most significant simulated microgravity-affected genes, signal transduction pathways, and biological processes which are relevant for mESCs differentiation have been identified and discussed below.
authors.forename: Vaibhav
authors.initials: V
authors.lastname: Shinde
authors.forename: Sonja
authors.initials: S
authors.lastname: Brungs
authors.forename: Margit
authors.initials: M
authors.lastname: Henry
authors.forename: Lucia
authors.initials: L
authors.lastname: Wegener
authors.forename: Harshal
authors.initials: H
authors.lastname: Nemade
authors.forename: Tamara
authors.initials: T
authors.lastname: Rotshteyn
authors.forename: Aviseka
authors.initials: A
authors.lastname: Acharya
authors.forename: Christa
authors.initials: C
authors.lastname: Baumstark-Khan
authors.forename: Christine E
authors.initials: CE
authors.lastname: Hellweg
authors.forename: Jürgen
authors.initials: J
authors.lastname: Hescheler
authors.forename: Ruth
authors.initials: R
authors.lastname: Hemmersbach
authors.forename: Agapios
authors.initials: A
authors.lastname: Sachinidis
mesh_terms: D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D059447:Cell Cycle Checkpoints; D002454:Cell Differentiation; D055515:Cysteine-Rich Protein 61 / Q000235:genetics / Q000378:metabolism; D058732:Embryoid Bodies / Q000502:physiology; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D060588:LIM Domain Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D000066450:Mouse Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D054839:Retinol-Binding Proteins, Plasma / Q000235:genetics / Q000378:metabolism; D059467:Transcriptome; D014335:Tropomyosin / Q000235:genetics / Q000378:metabolism; D020107:Troponin T / Q000235:genetics / Q000378:metabolism; D018474:Weightlessness Simulation; D000097642:GADD45 Proteins
chemical_list: D000429:Alcohol Oxidoreductases; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D055515:Cysteine-Rich Protein 61; D036341:Intercellular Signaling Peptides and Proteins; D047908:Intracellular Signaling Peptides and Proteins; D060588:LIM Domain Proteins; D009124:Muscle Proteins; D054839:Retinol-Binding Proteins, Plasma; D014335:Tropomyosin; D020107:Troponin T; C491850:CCN1 protein, mouse; C512925:Dlk1 protein, mouse; C121373:Gadd45g protein, mouse; D000097642:GADD45 Proteins; C502487:Rbp4 protein, mouse; C490774:Tpm1 protein, mouse; C090114:cysteine and glycine-rich protein 3; C586097:DHRS3 protein, mouse