Chemokine expression by subchondral bone marrow stromal cells isolated from osteoarthritis (OA) and rheumatoid arthritis (RA) patients

Abstract

We analysed the spontaneous and cytokine-stimulated production and expression in vitro of IL-8, GROα, MCP-1, RANTES, MIP-1α, MIP-1β, by subchondral bone marrow stromal cells (BMSC) isolated from RA, OA, post- traumatic (PT) patients and normal donors (ND), BMSC were cultured in vitro in the presence or absence of IL-1β and tumour necrosis factor-alpha (TNF- α), and assessed for chemokine production, expression and immunolocalization. BMSC from different sources constitutively released MCP- 1, GROα and IL-8, but not MIP-1α or MIP-1β, while BMSC from ND constitutively released only IL-8 and MCP-1. IL-8, GROα and RANTES production in basal conditions was significantly higher in RA patients than in ND. RANTES production was also higher in OA and RA than in PT patients. The combination of TNF-α and IL-1β synergistically increased the production of all chemokines tested except for RANTES. Reverse transcriptase-polymerase chain reaction (RT-PCR) demonstrated that all chemokines not detectable in the supernatants were expressed at the mRNA level. Chemokine immunostaining was localized around the nuclei. This work demonstrates that BMSC from subchondral bone produce chemokines and indicates that these cells could actively participate in the mechanisms directly or indirectly causing cartilage destruction and bone remodelling.