title: Effects of low oxygen tension on gene profile of soluble growth factors in co-cultured adipose-derived stromal cells and chondrocytes.
abstract: OBJECTIVE
  Moving towards development of optimized cartilage regeneration with adipose-derived stromal cells (ASCs), the focus of this study was on investigating the influence of hypoxia on soluble factors secreted by ASCs and chondrocytes after crosstalk.
  
  
  METHODS
  We established direct contact co-culture and non-contact co-culture systems by using red or green fluorescent protein (R/GFP)-labelled mice and SD rats respectively. Gene variation of growth factors of the two cell types, in both hypoxic and normoxic conditions, were screened using semi-quantitative polymerase chain reaction (PCR).
  
  
  RESULTS
  Co-culture with ASCs and chondrocytes under hypoxia was shown to successfully induce or enhance ASC to chondrogenic differentiation. To be specific, chondrogenic maker genes: AGC, COL II and SOX9 were remarkably enhanced in both ASCs and chondrocytes after crosstalk under low oxygen tension. Subsequently, screening growth factors in ASCs and chondrocytes under hypoxia showed that HIF-1α, VEGF-A/B, BMP-2/-4/-6, FGF-2 and IGF-1 were significantly increased, but not TGF-β1.
  
  
  CONCLUSIONS
  These results revealed that both hypoxia and co-culture systems can notably enhance chondrogenesis of ASCs as well as increase proliferation of ASCs and chondrocytes.
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China.
authors.forename: Sirong
authors.initials: S
authors.lastname: Shi
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Xie
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Zhong
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China.
authors.forename: Shiyu
authors.initials: S
authors.lastname: Lin
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China.
authors.forename: Na
authors.initials: N
authors.lastname: Fu
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China.
authors.forename: Xiaoru
authors.initials: X
authors.lastname: Shao
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China.
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Lin
mesh_terms: D000273:Adipose Tissue / Q000166:cytology* / Q000378:metabolism; D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000235:genetics; D002454:Cell Differentiation; D015687:Cell Hypoxia; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology* / Q000378:metabolism; D020219:Chondrogenesis; D018920:Coculture Techniques; D005260:Female; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic; D010100:Oxygen / Q000378:metabolism*; D017207:Rats, Sprague-Dawley; D017154:Stromal Cells / Q000166:cytology / Q000378:metabolism; D059467:Transcriptome
chemical_list: C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D036341:Intercellular Signaling Peptides and Proteins; D010100:Oxygen