Role of Notch-1 intracellular domain in activation of rheumatoid synoviocytes

Arthritis Rheum. 2001 Jul;44(7):1545-54. doi: 10.1002/1529-0131(200107)44:7<1545::AID-ART278>3.0.CO;2-Q.


Objective: Notch family proteins are transmembrane receptors that control cell fate and proliferation. Rheumatoid arthritis (RA) is characterized by activation and abnormal proliferation/differentiation of synoviocytes. We examined the expression of Notch-1 and its role in the activation of RA synoviocytes.

Methods: The expression of Notch-1 protein was detected by a specific antibody raised against the Notch-1 intracellular domain. Notch-1 messenger RNA (mRNA) expression in synoviocytes was analyzed by Northern blotting. Notch-1 protein expression was confirmed by Western blotting with anti-Notch-1 antibody. To analyze the role of Notch-1 in synoviocyte proliferation, we examined the effects of antisense Notch-1 oligonucleotides (ODNs) and MW167, a gamma-secretase inhibitor.

Results: Notch-1 protein and mRNA were detected in synovium from all study subjects. The nucleus of RA synoviocytes showed strong staining with anti-Notch-1 antibody, whereas there was predominantly cytoplasmic staining of normal and osteoarthritis (OA) synoviocytes. Western blotting showed a distinct approximately 63-kd protein detected by anti-Notch-1 antibody in nuclear extracts from RA synoviocytes, indicating that nuclear staining of RA synovium and synoviocytes is likely to be the result of nuclear localization of Notch-1 intracellular domain (NICD). Furthermore, tumor necrosis factor alpha (TNFalpha) increased NICD nuclear translocation in a dose-dependent manner. Antisense Notch-1 ODNs partially blocked the proliferation of RA synoviocytes and inhibited TNFalpha-induced proliferation in both OA and RA synoviocytes. In addition, gamma-secretase inhibitor, which blocks the production of NICD, also inhibited TNFalpha-induced proliferation of RA synoviocytes.

Conclusion: Our results demonstrate the expression of Notch-1 in synoviocytes and the presence of Notch-1 fragment in the nuclei of RA synoviocytes and suggest the involvement of Notch-1 signaling in the TNFalpha-induced proliferation of RA synoviocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyloid Precursor Protein Secretases
  • Antisense Elements (Genetics)
  • Arthritis, Rheumatoid / pathology*
  • Arthritis, Rheumatoid / physiopathology
  • Aspartic Acid Endopeptidases
  • Blotting, Northern
  • Blotting, Western
  • Cell Division / drug effects
  • Cell Division / physiology
  • Cell Nucleus / chemistry
  • Cells, Cultured
  • Endopeptidases / metabolism
  • Enzyme Inhibitors / pharmacology
  • Fluorescent Antibody Technique
  • Gene Expression / drug effects
  • Humans
  • Membrane Proteins / analysis
  • Membrane Proteins / chemistry*
  • Membrane Proteins / genetics*
  • Osteoarthritis, Knee / pathology*
  • Osteoarthritis, Knee / physiopathology
  • Peptides*
  • Protein Structure, Tertiary
  • RNA, Messenger / analysis
  • Receptor, Notch1
  • Receptors, Cell Surface*
  • Signal Transduction / physiology
  • Synovial Membrane / chemistry
  • Synovial Membrane / pathology*
  • Transcription Factors*
  • Tumor Necrosis Factor-alpha / pharmacology


  • Antisense Elements (Genetics)
  • Enzyme Inhibitors
  • MW167
  • Membrane Proteins
  • NOTCH1 protein, human
  • Peptides
  • RNA, Messenger
  • Receptor, Notch1
  • Receptors, Cell Surface
  • Transcription Factors
  • Tumor Necrosis Factor-alpha
  • Amyloid Precursor Protein Secretases
  • Endopeptidases
  • Aspartic Acid Endopeptidases
  • BACE1 protein, human