Enhanced neutral protease activity in proliferating rheumatoid synovial cells

Area of Science:

• Biochemistry
• Cell Biology
• Rheumatology

Background:

• Proteolytic enzymes from rheumatoid synovial cells (RSC) are linked to articular cartilage degradation.
• Understanding protease activity in different synovial cell states is crucial for rheumatoid arthritis research.

Purpose of the Study:

• To quantify and compare protease activity in proliferating and non-proliferating rheumatoid (RSC) and non-rheumatoid synovial cells (NSC).
• To investigate the relationship between cell origin, proliferative state, and protease activity.

Main Methods:

• Measurement of total surface-associated and secreted neutral protease activity.
• Assay of secreted proteases alone.
• Analysis of extractable cellular protease activity at various pH levels.
• Comparison between early-passaged and serially-passaged cells.

Main Results:

• Proliferating RSC (P-RSC) and NSC (P-NSC) showed enhanced neutral protease activity compared to non-proliferating cells.
• P-RSC exhibited significantly higher neutral protease activity than P-NSC.
• RSC secreted higher levels of proteases than NSC, irrespective of proliferative state.
• Elevated extractable cellular protease activity was found in RSC compared to NSC, particularly in early-passaged cells.

Conclusions:

• Synovial cell protease activity is influenced by both proliferative state and cell origin.
• Proliferating rheumatoid synovial cells display the highest levels of neutral protease activity.
• RSC possess higher overall extractable protease activity, suggesting a key role in rheumatoid arthritis pathogenesis.