p38 mitogen-activated protein kinase functionally contributes to chondrogenesis induced by growth/differentiation factor-5 in ATDC5 cells

Exp Cell Res. 1999 Aug 1;250(2):351-63. doi: 10.1006/excr.1999.4535.

Abstract

Recent studies of intracellular signal transduction mechanisms for the transforming growth factor-beta (TGF-beta) superfamily have focused on Smad proteins, but have paid little attention to mitogen-activated protein (MAP) kinase cascades. Here we demonstrate that growth/differentiation factor-5 (GDF-5), but neither bone morphogenetic protein-2 (BMP-2) nor TGF-beta1, fully promotes the early phase of the chondrogenic response by inducing cellular condensation followed by cartilage nodule formation in a mouse chondrogenic cell line, ATDC5. We investigated which, if any, of the three major types of MAP kinase plays a functional role in the promotion of chondrogenesis induced by GDF-5. GDF-5 induced phosphorylation of p38 MAP kinase and extracellular signal-regulated kinase (ERK) but not that of c-Jun N-terminal kinase (JNK). The phosphorylation of p38 MAP kinase was also induced by BMP-2 and TGF-beta1. An inhibitor of p38 and p38 beta MAP kinase, SB202190, showed complete inhibition of cartilage nodule formation but failed to affect alkaline phosphatase (ALP) activity induced by GDF-5. Expression of the type II collagen gene, a hallmark of chondrogenesis in vertebrates, was also induced by GDF-5 treatment and strongly suppressed by SB202190. On the other hand, although an inhibitor of MAP/ERK kinase, PD98059, inhibited the rapid phosphorylation of ERK by GDF-5, it inhibited neither ALP activity nor cartilage nodule formation induced by GDF-5. These results strongly suggest that the p38 MAP kinase cascade is involved in GDF-5 signaling pathways and that a role of the p38 MAP kinase pathway is necessary over a longer period to promote chondrogenesis in ATDC5 cells.

MeSH terms

  • Alkaline Phosphatase / metabolism
  • Animals
  • Bone Morphogenetic Protein 2
  • Bone Morphogenetic Proteins / pharmacology
  • Calcium-Calmodulin-Dependent Protein Kinases / antagonists & inhibitors
  • Calcium-Calmodulin-Dependent Protein Kinases / metabolism*
  • Carcinoma, Embryonal
  • Cartilage / drug effects
  • Cartilage / metabolism
  • Cell Differentiation / drug effects
  • Cell Size / drug effects
  • Chondrogenesis / drug effects*
  • Collagen / genetics
  • Dose-Response Relationship, Drug
  • Enzyme Induction / drug effects
  • Growth Differentiation Factor 5
  • Growth Substances / pharmacology*
  • Humans
  • JNK Mitogen-Activated Protein Kinases
  • MAP Kinase Kinase 1
  • Mice
  • Mitogen-Activated Protein Kinase Kinases*
  • Mitogen-Activated Protein Kinases*
  • Phosphorylation / drug effects
  • Protein Serine-Threonine Kinases / antagonists & inhibitors
  • Protein Serine-Threonine Kinases / metabolism
  • Protein-Tyrosine Kinases / antagonists & inhibitors
  • Protein-Tyrosine Kinases / metabolism
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Signal Transduction / drug effects
  • Transforming Growth Factor beta / pharmacology
  • Tumor Cells, Cultured
  • p38 Mitogen-Activated Protein Kinases

Substances

  • BMP2 protein, human
  • Bmp2 protein, mouse
  • Bone Morphogenetic Protein 2
  • Bone Morphogenetic Proteins
  • GDF5 protein, human
  • Gdf5 protein, mouse
  • Growth Differentiation Factor 5
  • Growth Substances
  • RNA, Messenger
  • Transforming Growth Factor beta
  • Collagen
  • Protein-Tyrosine Kinases
  • Protein Serine-Threonine Kinases
  • Calcium-Calmodulin-Dependent Protein Kinases
  • JNK Mitogen-Activated Protein Kinases
  • Mitogen-Activated Protein Kinases
  • p38 Mitogen-Activated Protein Kinases
  • MAP Kinase Kinase 1
  • MAP2K1 protein, human
  • Map2k1 protein, mouse
  • Mitogen-Activated Protein Kinase Kinases
  • Alkaline Phosphatase