title: Cyclic mechanical stress modulates neurotrophic and myelinating gene expression of Schwann cells.
abstract: OBJECTIVE
  This study aimed to investigate the response of Schwann cells to cyclic compressive and tensile stresses of different durations of stimulation.
  
  
  METHODS
  RSC96 cells were subjected to cyclic tensile stress or compressive stress; for either, cells in five groups were treated for 0, 1, 2, 24 and 48 h respectively. Enzyme-linked immunosorbent assay was conducted to detect secretion of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 and neurotrophin-4 in the culture medium. Real-time PCR was conducted to quantify mRNA expression of neurotrophins including NGF, BDNF, neurotrophin-3 and neurotrophin-4, and myelin-related genes including Sox10, Krox20, neuregulin 1, NCAM, N-cadherin, P0, MAG and MBP. Immunofluorescent staining was performed to visualize Krox20 and F-actin in the tensile groups.
  
  
  RESULTS
  Within 24 h, cells treated with cyclic tensile stress expressed and secreted significantly more BDNF, while cyclic compression down-regulated BDNF expression. Cells treated with both tensile and compressive stress down-regulated expression of NRG1, NCAM, Krox20 and Sox10 at all time points. Expression of N-cadherin was not affected by either stretch or compression. F-actin was down-regulated by tensile stress.
  
  
  CONCLUSIONS
  Both tensile and compressive loading down-regulated expression of several important myelin-related Schwann cells genes and thus facilitated demyelination. Tensile stress meanwhile promoted secretion of BDNF by Schwann cells within 24 h, which may contribute to maintenance and repair of damaged axons. These effects of mechanical stress might have been mediated by the actin cytoskeleton.
authors.affiliation: State Key Laboratory of Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, 610041, China.
authors.forename: L
authors.initials: L
authors.lastname: Zhang
authors.forename: X
authors.initials: X
authors.lastname: Yang
authors.forename: Y
authors.initials: Y
authors.lastname: Yue
authors.forename: J
authors.initials: J
authors.lastname: Ye
authors.forename: Y
authors.initials: Y
authors.lastname: Yao
authors.forename: Y
authors.initials: Y
authors.lastname: Fu
authors.forename: G
authors.initials: G
authors.lastname: Li
authors.forename: Q
authors.initials: Q
authors.lastname: Yao
authors.forename: Y
authors.initials: Y
authors.lastname: Lin
authors.forename: P
authors.initials: P
authors.lastname: Gong
mesh_terms: D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002460:Cell Line; D051767:Early Growth Response Protein 2 / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D009186:Myelin Sheath / Q000378:metabolism*; D051381:Rats; D012583:Schwann Cells / Q000378:metabolism*; D013314:Stress, Mechanical
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D015815:Cell Adhesion Molecules; D051767:Early Growth Response Protein 2