title: TOB1 Deficiency Enhances the Effect of Bone Marrow-Derived Mesenchymal Stem Cells on Tendon-Bone Healing in a Rat Rotator Cuff Repair Model.
abstract: OBJECTIVE
  This study investigated the effect of silencing TOB1 (Transducer of ERBB2, 1) expression in bone marrow-derived mesenchymal stem cells (MSCs) on MSC-facilitated tendon-bone healing in a rat supraspinatus repair model.
  
  
  METHODS
  Rat MSCs were transduced with a recombinant lentivirus encoding short hairpin RNA (shRNA) against TOB1. MSC cell proliferation was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. The effect of MSCs with TOB1 deficiency on tendon-bone healing in a rat rotator cuff repair model was evaluated by biomechanical testing, histological analysis and collagen type I and II gene expression. An upstream regulator (miR-218) of TOB1 was determined in MSCs.
  
  
  RESULTS
  We found that knockdown of TOB1 significantly increased the proliferative activity of rat MSCs in vitro. When MSCs with TOB1 deficiency were injected into injured rat supraspinatus tendon-bone junctions, the effect on tendon-bone healing was enhanced compared to treatment with control MSCs with normal TOB1 expression, as evidenced by elevated levels of ultimate load to failure and stiffness, increased amount of fibrocartilage and augmented expression of collagen type I and type II genes. In addition, we found that the TOB1 3' untranslated region is a direct target of miR-218. Similar to the effect of TOB1 deficiency, overexpression of miR-218 effectively promoted tendon-bone healing in rat.
  
  
  CONCLUSIONS
  These results suggest that TOB1 may play a negative role in the effect of MSCs on tendon-bone healing, and imply that expression of TOB1 may be regulated by miR-218.
authors.affiliation: Department of Orthopedics, Changhai Hospital, Second Military Medical University, Shanghai, China.
authors.forename: Yulei
authors.initials: Y
authors.lastname: Gao
authors.forename: Yinquan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yanghu
authors.initials: Y
authors.lastname: Lu
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.forename: Xingrui
authors.initials: X
authors.lastname: Kou
authors.forename: Yi
authors.initials: Y
authors.lastname: Lou
authors.forename: Yifan
authors.initials: Y
authors.lastname: Kang
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology; D049109:Cell Proliferation; D002478:Cells, Cultured; D024042:Collagen Type I / Q000378:metabolism; D024043:Collagen Type II / Q000378:metabolism; D004195:Disease Models, Animal; D016086:Lentivirus / Q000235:genetics; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism; D035683:MicroRNAs / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D016376:Oligonucleotides, Antisense / Q000378:metabolism; D034622:RNA Interference; D051381:Rats; D017207:Rats, Sprague-Dawley; D012097:Repressor Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D017006:Rotator Cuff / Q000473:pathology*; D013708:Tendon Injuries / Q000473:pathology / Q000628:therapy*; D013710:Tendons / Q000473:pathology*; D014945:Wound Healing
chemical_list: D024042:Collagen Type I; D024043:Collagen Type II; D035683:MicroRNAs; D016376:Oligonucleotides, Antisense; D012097:Repressor Proteins; C508773:Tob1 protein, rat