title: Pim-1 is up-regulated by shear stress and is involved in shear stress-induced proliferation of rat mesenchymal stem cells.
abstract: OBJECTIVE
  Investigation of the response of mesenchymal stem cells (MSCs) to vascular mechanical forces is very important in the field of cardiovascular intervention. Ser/Thr-protein kinase Pim-1 is a novel transducer of cell survival and the cell cycle that promotes signals in the hematopoietic cell system. Current studies aim to foster an understanding of Pim-1 expression and regulation in MSCs in response to different durations and strengths of laminar shear stress (SS) and to investigate the role of Pim-1 in SS-induced cell proliferation.
  
  
  METHODS
  A parallel-plate flow chamber was used to control the strength and duration of SS. Proliferation was measured with the BrdU cell proliferation assay. The expressions of Pim-1 mRNA and protein were evaluated by reverse transcription-polymerase chain reaction and western blotting, respectively. RNA interference was used to knock down the Pim-1 gene.
  
  
  RESULTS
  The results showed that SS up-regulation of Pim-1 mRNA and protein was time-dependent. Pim-1 induction was SS strength-dependent, and the expression level reached a maximum at 30 dynes/cm(2). Inhibitors of p38MAPK and ERK attenuated the SS-induced expression of Pim-1. In addition, SS significantly increased BrdU-uptake, which was effectively blocked by the silencing of Pim-1.
  
  
  CONCLUSIONS
  These results demonstrated that Pim-1 is expressed in MSCs and plays an important role in the SS-induced proliferation of MSCs.
authors.affiliation: Department of Respiratory Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Ming-Li
authors.initials: ML
authors.lastname: Tu
authors.forename: Han-Qin
authors.initials: HQ
authors.lastname: Wang
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Sun
authors.forename: Long-Ju
authors.initials: LJ
authors.lastname: Chen
authors.forename: Xing-Chun
authors.initials: XC
authors.lastname: Peng
authors.forename: Ya-Hong
authors.initials: YH
authors.lastname: Yuan
authors.forename: Rui-Ming
authors.initials: RM
authors.lastname: Li
authors.forename: Xu-zhi
authors.initials: XZ
authors.lastname: Ruan
authors.forename: Dong-Sheng
authors.initials: DS
authors.lastname: Li
authors.forename: Yong-Jian
authors.initials: YJ
authors.lastname: Xu
authors.forename: Zun-Ji
authors.initials: ZJ
authors.lastname: Ke
mesh_terms: D000818:Animals; D015153:Blotting, Western; D049109:Cell Proliferation; D002478:Cells, Cultured; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism*; D051573:Proto-Oncogene Proteins c-pim-1 / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013314:Stress, Mechanical; D015854:Up-Regulation
chemical_list: D012333:RNA, Messenger; D051573:Proto-Oncogene Proteins c-pim-1