title: Zinc-finger protein 145, acting as an upstream regulator of SOX9, improves the differentiation potential of human mesenchymal stem cells for cartilage regeneration and repair.
abstract: OBJECTIVE
  Human mesenchymal stem cells (hMSCs) represent one of the most promising stem cell therapies for traumatic injury and age-related degenerative diseases involving cartilage. However, few genetic factors regulating chondrogenesis of MSCs have been identified. One study showed that zinc-finger protein 145 (ZNF145), a transcription factor, was up-regulated during 3-lineage differentiation of hMSCs. The present study was undertaken to validate whether this novel transcription factor is useful for the repair and regeneration of cartilage.
  
  
  METHODS
  Human MSCs were transfected with lentiviral short hairpin RNA (for small interfering RNA knockdown of ZNF145) and a lentiviral vector for overexpression of ZNF145, and the effects of ZNF145 on chondrogenesis were studied using quantitative polymerase chain reaction and immunostaining. Microarray and transient expression analyses were used to determine whether ZNF145 is a factor operating upstream of SOX9. Allogeneic transplantation of hMSCs into osteochondral defects in rats was performed to determine the effects of ZNF145 on repair of cartilage in vivo.
  
  
  RESULTS
  Small interfering RNA-mediated gene silencing of ZNF145 slowed down chondrogenesis, whereas overexpression of ZNF145 enhanced chondrogenesis. Global gene expression profiling showed up-regulated gene expression in ZNF145-overexpressing MSCs, and transient overexpression of ZNF145 enhanced the expression of SOX9, suggesting that ZNF145 acts as a factor upstream of SOX9, the master regulator of chondrogenesis. Moreover, allogeneic transplantation of hMSCs into osteochondral defects of rat knees showed that ZNF145-overexpressing MSCs repaired cartilage defects better and earlier than empty control MSCs.
  
  
  CONCLUSIONS
  These findings suggest that ZNF145 gene therapy may be a very useful strategy for improving the quality of cartilage regeneration and repair.
authors.affiliation: Department of Orthopaedic Surgery, National University of Singapore and Genome Institute of Singapore, Singapore. dosltm@nus.edu.sg
authors.forename: Tong Ming
authors.initials: TM
authors.lastname: Liu
authors.forename: Xi Min
authors.initials: XM
authors.lastname: Guo
authors.forename: Hwee San
authors.initials: HS
authors.lastname: Tan
authors.forename: James H
authors.initials: JH
authors.lastname: Hui
authors.forename: Bing
authors.initials: B
authors.lastname: Lim
authors.forename: Eng Hin
authors.initials: EH
authors.lastname: Lee
mesh_terms: D000818:Animals; D002356:Cartilage / Q000378:metabolism*; D019070:Cell Lineage; D019902:Chondrocytes / Q000378:metabolism; D020219:Chondrogenesis / Q000502:physiology*; D006801:Humans; D051741:Kruppel-Like Transcription Factors / Q000378:metabolism*; D008297:Male; D059630:Mesenchymal Stem Cells / Q000378:metabolism*; D000075722:Promyelocytic Leukemia Zinc Finger Protein; D034741:RNA, Small Interfering; D051381:Rats; D017207:Rats, Sprague-Dawley; D012038:Regeneration / Q000502:physiology; D055758:SOX9 Transcription Factor / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology
chemical_list: D051741:Kruppel-Like Transcription Factors; D000075722:Promyelocytic Leukemia Zinc Finger Protein; D034741:RNA, Small Interfering; D055758:SOX9 Transcription Factor; C092037:ZBTB16 protein, human