High mobility group box-1 (HMGB-1) in osteoarthritic cartilage.

Abstract

In resting chondrocytes tight nucleosomal HMGB-1 binding might cause steric hindrance of immunostaining. TNF-alpha- or OA-mediated activation leads to nuclear staining and cytoplasmic translocation. Advancing OA leads to increasingly intense extra-/pericellular deposition of HMGB-1 alarmin, indicating local chondrocyte activation and/or necrosis. In particular, HMGB-1 at the tidemark might play a role in the pathological thickening of subchondral bone plate/osteophyte formation.