title: Scleraxis Is Essential for Tendon Differentiation by Equine Embryonic Stem Cells and in Equine Fetal Tenocytes.
abstract: The transcription factor scleraxis is required for tendon development and is upregulated during embryonic stem cell (ESC) differentiation into tenocytes. However, its role beyond early embryonic development is not defined. We utilized a short hairpin RNA to knock down scleraxis expression in ESCs and adult and fetal tenocytes. No effect on growth or morphology was observed in two-dimensional cultures. However, scleraxis knockdown in fetal tenocytes significantly reduced COL1A1, COMP, and SOX9 gene expression. Scleraxis knockdown in adult tenocytes had no effect on the expression of these genes. Strikingly, differentiating ESCs and fetal tenocytes without scleraxis failed to reorganize a three-dimensional (3D) matrix and generate artificial tendons. This was associated with a significantly reduced survival. In contrast, there was no effect on the survival and remodeling capacity of adult tenocytes following scleraxis knockdown. Overexpression of scleraxis in fetal tenocytes rescued gene expression, cell survival in 3D, and subsequent matrix contraction. Together, these results demonstrate that scleraxis is not only essential for ESC differentiation into tenocytes but that it also has an active role in maintaining fetal tenocytes, which is then redundant in adult tenocytes.
authors.affiliation: 1 Centre for Preventive Medicine , Animal Health Trust, Newmarket, United Kingdom .
authors.forename: Emma P
authors.initials: EP
authors.lastname: Bavin
authors.affiliation: 1 Centre for Preventive Medicine , Animal Health Trust, Newmarket, United Kingdom .
authors.forename: Francesca
authors.initials: F
authors.lastname: Atkinson
authors.affiliation: 1 Centre for Preventive Medicine , Animal Health Trust, Newmarket, United Kingdom .
authors.forename: Tom
authors.initials: T
authors.lastname: Barsby
authors.affiliation: 1 Centre for Preventive Medicine , Animal Health Trust, Newmarket, United Kingdom .
authors.forename: Debbie J
authors.initials: DJ
authors.lastname: Guest
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D064236:Cartilage Oligomeric Matrix Protein / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D005333:Fetus / Q000166:cytology*; D005782:Gels / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D055785:Gene Knockdown Techniques; D006736:Horses; D034741:RNA, Small Interfering / Q000378:metabolism; D055758:SOX9 Transcription Factor / Q000235:genetics / Q000378:metabolism; D013710:Tendons / Q000166:cytology*; D000070916:Tenocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D064236:Cartilage Oligomeric Matrix Protein; D024042:Collagen Type I; D018076:DNA, Complementary; D005782:Gels; D034741:RNA, Small Interfering; D055758:SOX9 Transcription Factor
keywords: embryonic stem cells; scleraxis; tendon