title: The increase in O-linked N-acetylglucosamine protein modification stimulates chondrogenic differentiation both in vitro and in vivo.
abstract: Insulin is an inducer of chondrocyte hypertrophy and growth plate chondrogenesis, although the specific molecular mechanisms behind these effects are mostly unknown. Our aim was to investigate whether insulin-induced chondrocyte hypertrophy occurs through a modification in the amount of O-linked N-acetylglucosamine (O-GlcNAc)-modified proteins and in the expression of the key enzymes of this pathway, O-GlcNAc transferase and O-GlcNAcase (OGA). We also studied if O-GlcNAc accumulation per se, induced by an OGA inhibitor, was able to induce pre-hypertrophic chondrocyte differentiation both in vitro and in vivo. Insulin-induced differentiation of ATDC5 pre-chondrocytes occurred alongside a gradual increase in the accumulation of O-GlcNac-modified proteins (O-GlcNAcylated proteins), as well as an increase in the expression of O-GlcNAc transferase and OGA. In the absence of insulin, O-GlcNAc accumulation induced by thiamet-G, a specific OGA inhibitor, was able to increase the gene expression of differentiation markers, as well as the activity of MMP-2 and -9. Thiamet-G also activated pERK, p-JNK, and p-p38 and the O-GlcNAcylation of Akt. Thiamet-G administration to C57/bl mice induced a significant expansion in the growth plate height and in the hypertrophic zone height. Therefore, our results show that O-GlcNAc glycosylation has chondromodulating activity.
authors.affiliation: Joint and Bone Research Unit, IIS-Fundación Jiménez Díaz, Universidad Autónoma de Madrid, Madrid, Spain.
authors.forename: Jessica
authors.initials: J
authors.lastname: Andrés-Bergós
authors.forename: Lidia
authors.initials: L
authors.lastname: Tardio
authors.forename: Ane
authors.initials: A
authors.lastname: Larranaga-Vera
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Gómez
authors.forename: Gabriel
authors.initials: G
authors.lastname: Herrero-Beaumont
authors.forename: Raquel
authors.initials: R
authors.lastname: Largo
mesh_terms: D000117:Acetylglucosamine / Q000737:chemistry*; D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D019902:Chondrocytes / Q000166:cytology* / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D006984:Hypertrophy; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism; D008297:Male; D020782:Matrix Metalloproteinases / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D017351:N-Acetylglucosaminyltransferases / Q000378:metabolism*; D015398:Signal Transduction; D014018:Tissue Distribution
chemical_list: D007328:Insulin; D017351:N-Acetylglucosaminyltransferases; C449880:O-GlcNAc transferase; D020782:Matrix Metalloproteinases; D000117:Acetylglucosamine