Expression of heat shock protein receptors on fibroblast-like synovial cells derived from rheumatoid arthritis-affected joints

• Published in: Rheumatology international Vol. 28; no. 9; pp. 837 - 844
• Main Authors: Hromadnikova, Ilona, Nguyen, Thi Thu Hien, Zlacka, Denisa, Sedlackova, Lucie, Popelka, Stanislav, Veigl, David, Pech, Jan, Vavrincova, Pavla, Sosna, Antonin
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.07.2008; Springer Nature B.V
• Subjects: Adult; Aged; Antigens, CD - metabolism; Arthritis, Rheumatoid - metabolism; Cohort Studies; Female; Fibroblasts - metabolism; HSP70 Heat-Shock Proteins - metabolism; HSP72 Heat-Shock Proteins - metabolism; Humans; Low Density Lipoprotein Receptor-Related Protein-1; Male; Medicine; Medicine & Public Health; Middle Aged; Original Article; Rheumatoid arthritis; Rheumatology; Synovial Fluid; Synovial Membrane - metabolism; Inducible Hsp70; CD91; Rheumatoid arthritis; Synovial cells
• ISSN: 0172-8172; 1437-160X
• DOI: 10.1007/s00296-008-0532-9

We examined the membrane expression of inducible Hsp70 and HSP receptors like TLR2, TLR4, CD14, CD36, CD40 and CD91 on fibroblast-like synovial cells (SC) derived from synovial tissue in 23 patients with rheumatoid arthritis (RA), who underwent synovectomy by using flow cytometric analysis. For comparison, autologous skin fibroblasts (SF) derived from the operation wound were tested. Significantly higher Hsp70 expression was found on synovial cells than on skin fibroblasts (median SC 21.4% × SF 5.0%, P <  0.001). Both synovial cells and skin fibroblasts expressed high levels of cell surface CD91 (median SC 80.2% × SF 79.2%), however, no or low levels of CD14, CD40, TLR2, TLR4 and CD36. Further, we observed high co-expression of CD91 and Hsp70 on RA synovial cells (median 18.6%), while skin fibroblasts showed only background Hsp70 expression (median 3.9%, P <  0.001). Since we demonstrated the high prevalence of inducible Hsp70 in RA synovial fluids, we speculate that Hsp70 might be captured onto the membrane of synovial cells from the extracellular space via the CD91 receptor. The significance of the Hsp70 interaction with synovial cells via CD91 remains undefined, but may mediate other non-immune purposes.