Heme oxygenase-1 induction modulates microsomal prostaglandin E synthase-1 expression and prostaglandin E[sub]2 production in osteoarthritic chondrocytes

• Published in: Biochemical pharmacology 2009-06, Vol.77 (12), p.1806-1813
• Main Authors: Megias, Javier, Guillen, Maria Isabel, Clerigues, Victoria, Rojo, Ana I, Cuadrado, Antonio, Castejon, Miguel Angel, Gomar, Francisco, Alcaraz, Maria Jose
• Format: Article
• Language: English
• ISSN: 0006-2952
• DOI: 10.1016/j.bcp.2009.03.009

Pro-inflammatory cytokines such as interleukin-1[beta] (IL-1[beta]) may participate in the pathogenesis of cartilage damage in osteoarthritis (OA) through the production of catabolic enzymes and inflammatory mediators. Induction of heme oxygenase-1 (HO-1) has previously been shown to exert anti-inflammatory effects in different cell types. We have investigated whether HO-1 induction may modify chondrocyte viability and the production of relevant mediators such as oxidative stress and prostaglandin E[sub]2 (PGE[sub]2) elicited by IL-1[beta] in OA chondrocytes. Chondrocytes were isolated from OA cartilage and used in primary culture. Cells were stimulated with IL-1[beta] in the absence or presence of the HO-1 inducer cobalt protoporphyrin IX (CoPP). Gene expression was assessed by quantitative real-time PCR, protein levels by ELISA and Western blot, apoptosis by laser scanning cytometry using annexin V-FITC and TUNEL assays, and oxidative stress by LSC with dihydrorhodamine 123. HO-1 induction by CoPP enhanced chondrocyte viability and aggrecan content while inhibiting apoptosis and oxidative stress generation. PGE[sub]2 is produced in OA chondrocytes stimulated by IL-1[beta] by the coordinated induction of cyclooxygenase-2 and microsomal PGE synthase 1 (mPGES-1). The production of PGE[sub]2 was decreased by HO-1 induction as a result of diminished mPGES-1 protein and mRNA expression. Transfection with HO-1 small interfering RNA counteracted CoPP effects. In addition, the activation of nuclear factor-[kappa]B and early growth response-1 was significantly reduced by CoPP providing a basis for its anti-inflammatory effects. These results confirm the protective role of HO-1 induction in OA chondrocytes and suggest the potential interest of this strategy in degenerative joint diseases..