RESUMEN
We recently reported that cyclin-dependent kinase inhibitor 1 (p21) deficiency induces osteoarthritis susceptibility. Here, we determined the mechanism underlying the effect of p21 in synovial and cartilage tissues in RA. The knee joints of p21-knockout (p21-/-) (n = 16) and wild type C57BL/6 (p21+/+) mice (n = 16) served as in vivo models of collagen antibody-induced arthritis (CAIA). Arthritis severity was evaluated by immunological and histological analyses. The response of p21 small-interfering RNA (siRNA)-treated human RA FLSs (n = 5 per group) to interleukin (IL)-1ß stimulation was determined in vitro. Arthritis scores were higher in p21-/- mice than in p21+/+ mice. More severe synovitis, earlier loss of Safranin-O staining, and cartilage destruction were observed in p21-/- mice compared to p21+/+ mice. p21-/- mice expressed higher levels of IL-1ß, TNF-α, F4/80, CD86, p-IKKα/ß, and matrix metalloproteinases (MMPs) in cartilage and synovial tissues via IL-1ß-induced NF-kB signaling. IL-1ß stimulation significantly increased IL-6, IL-8, and MMP expression, and enhanced IKKα/ß and IκBα phosphorylation in human FLSs. p21-deficient CAIA mice are susceptible to RA phenotype alterations, including joint cartilage destruction and severe synovitis. Therefore, p21 may have a regulatory role in inflammatory cytokine production including IL-1ß, IL-6, and TNF-α.
Asunto(s)
Artritis Experimental/genética , Artritis Reumatoide/genética , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/genética , Inflamación/genética , Interleucina-1beta/genética , Animales , Artritis Experimental/inducido químicamente , Artritis Experimental/patología , Artritis Reumatoide/inducido químicamente , Artritis Reumatoide/patología , Antígeno B7-2/genética , Proteínas de Unión al Calcio/genética , Cartílago/metabolismo , Cartílago/patología , Regulación de la Expresión Génica/efectos de los fármacos , Predisposición Genética a la Enfermedad , Humanos , Inflamación/inducido químicamente , Inflamación/patología , Interleucina-1beta/efectos adversos , Interleucina-1beta/farmacología , Interleucina-6/genética , Articulación de la Rodilla , Metaloproteinasas de la Matriz/genética , Ratones , Ratones Noqueados , Receptores Acoplados a Proteínas G/genética , Líquido Sinovial/metabolismo , Factor de Necrosis Tumoral alfa/genéticaRESUMEN
Eicosapentanoic acid (EPA) is an antioxidant and omega-3 polyunsaturated fatty acid that reduces inflammatory cytokine production. Gelatin hydrogel can be used as a carrier of a physiologically active substance that release it gradually for an average of ~3 weeks. Therefore, this study aimed to clarify the effect of EPA-incorporating gelatin hydrogels on osteoarthritis (OA) progression in vivo. Ten-week-old male C57BL/6J mice were randomly divided into six groups (n = 6): Sham, destabilization of the medial meniscus (DMM), Corn: DMM + 2 µL corn oil, EPA injection alone (EPA-I): DMM + 2 µL corn oil + 125 µg/µL EPA, Gel: DMM + gelatin hydrogels, and EPA-G: DMM + 125 µg/µL EPA-incorporating gelatin hydrogels. The mice were euthanized at 8 weeks after DMM or Sham surgery, and subjected to histological evaluation. Matrix-metalloproteinases-3 (MMP-3), MMP-13, interleukin-1ß (IL-1ß), p-IKK α/ß, CD86, and CD163 protein expression in the synovial cartilage was detected by immunohistochemical staining. F4/80 expression was also assessed using the F4/80 score of macrophage. Histological score was significantly lower in EPA-G than in EPA-I. MMP-3-, MMP-13-, IL-1ß-, and p-IKK α/ß-positive cell ratio was significantly lower in EPA-G than in EPA-I. However, CD86- and CD163-positive cell ratio was not significantly different between EPA-I and EPA-G. The average-sum F4/80 score of macrophage in EPA-G was significantly lower than that in EPA-I. EPA-incorporating gelatin hydrogels were shown to prevent OA progression in vivo more effectively than EPA injection alone. Our results suggested that intra-articular administration of controlled-release EPA can be a new therapeutic approach for treating OA.