ADAM15 modulates outside-in signalling in chondrocyte-matrix interactions

Area of Science:

• Biochemistry
• Cell Biology
• Biomedical Science

Background:

• ADAM15 is a transmembrane protein involved in cell interactions, upregulated in early osteoarthritis (OA).
• ADAM15 enhances chondrocyte adhesion to collagen matrix, potentially playing a homeostatic role in OA.
• Understanding ADAM15's function in chondrocytes is crucial for OA research.

Purpose of the Study:

• To identify functional domains of ADAM15 responsible for collagen II (CII) interaction.
• To investigate signaling events associated with ADAM15-mediated chondrocyte adhesion to CII.
• To explore the role of ADAM15 in chondrocyte-collagen matrix interactions.

Main Methods:

• Stable transfection of ADAM15 and deletion mutants into T/C28a4 chondrocyte cell line.
• Adhesion assays of transfected cells to Collagen II (CII).
• Western blotting for phosphoprotein analysis and co-immunoprecipitation for protein binding identification.

Main Results:

• The prodomain of ADAM15 is essential for enhancing chondrocyte adhesion to CII.
• A cell-adhesive function was identified for a metalloproteinase prodomain for the first time.
• The cytoplasmic tail of ADAM15 modulates focal adhesion kinase (FAK) autophosphorylation at Y397 during chondrocyte-collagen interaction.

Conclusions:

• ADAM15's prodomain plays a critical role in chondrocyte adhesion to the collagen matrix.
• ADAM15 influences outside-in signaling pathways, specifically FAK phosphorylation, during cell-matrix interactions.
• These findings contribute to understanding ADAM15's chondroprotective role in degenerative cartilage diseases like OA.