RESUMO
Osteoarthritis (OA) is a chronic disease of articular joints that leads to degeneration of both cartilage and subchondral bone. These degenerative changes are further aggravated by proinflammatory cytokines including IL-1ß and TNF-α. Previously, we have reported that IL-3, a cytokine secreted by activated T cells, protects cartilage and bone damage in murine models of inflammatory and rheumatoid arthritis. However, how IL-3 protects cartilage degeneration is not yet known. In this study, we investigated the role of IL-3 on cartilage degeneration under both in vitro and in vivo conditions. We found that both mouse and human chondrocytes show strong expression of IL-3R at gene and protein levels. IL-3 increases the expression of mouse chondrocyte-specific genes, Sox9 and collagen type IIa, which were downregulated by IL-1ß. Moreover, IL-3 downregulated IL-1ß- and TNF-α-induced expression of matrix metalloproteinases in both mouse and human chondrocytes. Interestingly, IL-3 reduces the degeneration of articular cartilage and subchondral bone microarchitecture in a mouse model of human OA. Moreover, IL-3 showed the preventive and therapeutic effects on cartilage degeneration induced by IL-1ß in micromass pellet cultures of human mesenchymal stem cells. Thus, to our knowledge, we provide the first evidence that IL-3 has therapeutic potential in amelioration of degeneration of articular cartilage and subchondral bone microarchitecture associated with OA.
Assuntos
Cartilagem Articular/patologia , Regulação para Baixo , Interleucina-3/uso terapêutico , Metaloproteinases da Matriz/genética , Osteoartrite/tratamento farmacológico , Animais , Cartilagem Articular/efeitos dos fármacos , Cartilagem Articular/imunologia , Células Cultivadas , Condrócitos/efeitos dos fármacos , Condrócitos/imunologia , Colágeno Tipo II/genética , Colágeno Tipo II/metabolismo , Modelos Animais de Doenças , Humanos , Interleucina-1beta/farmacologia , Interleucina-3/administração & dosagem , Interleucina-3/farmacologia , Subunidade alfa de Receptor de Interleucina-3/genética , Subunidade alfa de Receptor de Interleucina-3/metabolismo , Metaloproteinases da Matriz/metabolismo , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/imunologia , Camundongos , Osteoartrite/imunologia , Osteoartrite/fisiopatologia , Fatores de Transcrição SOX9/genética , Fatores de Transcrição SOX9/metabolismo , Fator de Necrose Tumoral alfa/farmacologiaRESUMO
IL-3 is an important cytokine that regulates hematopoiesis. We have previously demonstrated that IL-3 is a potent inhibitor of osteoclastogenesis and bone resorption. In the present study, we have investigated the role of IL-3 on human osteoblast differentiation and bone formation. We found that IL-3 in a dose-dependent manner increases osteoblast differentiation and matrix mineralization in human mesenchymal stem cells (MSCs). IL-3 significantly enhances the expression of osteoblast specific genes such as alkaline phosphatase, collagen type-I, osteocalcin and osteopontin; and Runx-2 and osterix transcription factors. Moreover, IL-3 induces the expression of bone morphogenetic protein-2 (BMP-2), and activates smad1/5/8. IL-3 enhances osteoblast differentiation and BMP-2 secretion through JAK/STAT pathway. Interestingly, IL-3 promotes in vivo bone regeneration ability of MSCs. Thus, we reveal for the first time that IL-3 enhances human osteoblast differentiation and bone formation in both in vitro and in vivo conditions, and suggest its therapeutic potential for bone formation in important bone diseases.
