SOX gene expression in human osteoarthritic cartilage.
OBJECTIVE
While the developmental role of the SOX transcription factors in fetal chondrocyte differentiation is well documented, much less is known about the expression of SOX family members in normal and osteoarthritic adult cartilage. Therefore, the aim of the present study was to present a thorough analysis of SOX gene expression in normal and osteoarthritic human adult cartilage.


METHODS
RNA from normal and osteoarthritic knee cartilage from human adults was analyzed by gene expression profiling using GeneChip technology (Affymetrix) and quantitative real time PCR.


RESULTS
Most members of the SOX transcription factor family showed no or very low expression levels in normal and osteoarthritic cartilage from adults. In contrast, SOX9 expression was fairly high in normal cartilage, amounting to approximately 20% of GAPDH levels. SOX9 transcript levels were substantially reduced in osteoarthritis. SOX6 levels were reduced, albeit starting from a low basis expression in normal tissue.


CONCLUSIONS
The presented data indicate that the role of the SOX transcription factor family in adult human cartilage is most probably restricted to a few members, with SOX9 being the most prominent. Furthermore, the reduction of SOX9 and SOX6 transcript levels in osteoarthritic chondrocytes might be responsible for the loss of phenotypic stability of osteoarthritic chondrocytes.
Institute of Pathology, University Hospital Leipzig, Leipzig, Germany.
Jochen
J
Haag
Pia M
PM
Gebhard
Thomas
T
Aigner
D000328:Adult; D002356:Cartilage / Q000378:metabolism*; D020869:Gene Expression Profiling; D006609:High Mobility Group Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007717:Knee; D010003:Osteoarthritis / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D055758:SOX9 Transcription Factor; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D006609:High Mobility Group Proteins; D012333:RNA, Messenger; D055758:SOX9 Transcription Factor; C527932:SOX9 protein, human; D014157:Transcription Factors