L Utomo1, Y M Bastiaansen-Jenniskens2, J A N Verhaar3, G J V M van Osch4. 1. Department of Orthopaedics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands. Electronic address: l.utomo@erasmusmc.nl. 2. Department of Orthopaedics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands. Electronic address: y.bastiaansen@erasmusmc.nl. 3. Department of Orthopaedics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands. Electronic address: j.verhaar@erasmusmc.nl. 4. Department of Orthopaedics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands; Department of Otorhinolaryngology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands. Electronic address: g.vanosch@erasmusmc.nl.
Abstract
OBJECTIVE: Macrophages play a crucial role in the progression of osteoarthritis (OA). Their phenotype may range from pro-inflammatory to anti-inflammatory. The aim of this study was to evaluate the direct effects of macrophage subtypes on cartilage by culturing macrophage conditioned medium (MCM) on human articular cartilage. DESIGN: Human OA cartilage explants were cultured with MCM of pro-inflammatory M(IFNγ+TNFα), or anti-inflammatory M(IL-4) or M(IL-10) human monocyte-derived macrophages. To assess effects of anti-inflammatory macrophages, the cartilage was cultured with a combination of MCM phenotypes as well as pre-stimulated with IFNγ+TNFα cartilage before culture with MCM. The reactions of the explants were assessed by gene expression, nitric oxide (NO) production and release of glycosaminoglycans (GAGs). RESULTS: M(IFNγ+TNFα) MCM affected OA cartilage by upregulation of IL1B (Interleukin 1β), IL6, MMP13 (Matrix Metalloproteinase-13) and ADAMTS5 (A Disintegrin And Metalloproteinase with Thrombospondin Motifs-5), while inhibiting ACAN (aggrecan) and COL2A1 (collagen type II). M(IL-10) upregulated IL1B and Suppressor of cytokine signaling 1 (SOCS1). NO production and GAG release by the cartilage was increased when cultured with M(IFNγ+TNFα) MCM. M(IL-4) and M(IL-10) did not inhibit the effects of M(IFNγ+TNFα) MCM of neither phenotype affected IFNγ+TNFα pre-stimulated cartilage, in which an inflammatory gene response was deliberately induced. CONCLUSION: M(IFNγ+TNFα) macrophages have a prominent direct effect on OA cartilage, while M(IL-4) and M(IL-10) do not inhibit the effects of M(IFNγ+TNFα), or IFNγ+TNFα induced inflammation of the cartilage. Therapies aiming at inhibiting cartilage degeneration may take this into account by directing suppression of pro-inflammatory macrophages or stimulation of anti-inflammatory macrophages.
OBJECTIVE: Macrophages play a crucial role in the progression of osteoarthritis (OA). Their phenotype may range from pro-inflammatory to anti-inflammatory. The aim of this study was to evaluate the direct effects of macrophage subtypes on cartilage by culturing macrophage conditioned medium (MCM) on humanarticular cartilage. DESIGN:Human OA cartilage explants were cultured with MCM of pro-inflammatory M(IFNγ+TNFα), or anti-inflammatory M(IL-4) or M(IL-10) human monocyte-derived macrophages. To assess effects of anti-inflammatory macrophages, the cartilage was cultured with a combination of MCM phenotypes as well as pre-stimulated with IFNγ+TNFα cartilage before culture with MCM. The reactions of the explants were assessed by gene expression, nitric oxide (NO) production and release of glycosaminoglycans (GAGs). RESULTS: M(IFNγ+TNFα) MCM affected OA cartilage by upregulation of IL1B (Interleukin 1β), IL6, MMP13 (Matrix Metalloproteinase-13) and ADAMTS5 (A Disintegrin And Metalloproteinase with Thrombospondin Motifs-5), while inhibiting ACAN (aggrecan) and COL2A1 (collagen type II). M(IL-10) upregulated IL1B and Suppressor of cytokine signaling 1 (SOCS1). NO production and GAG release by the cartilage was increased when cultured with M(IFNγ+TNFα) MCM. M(IL-4) and M(IL-10) did not inhibit the effects of M(IFNγ+TNFα) MCM of neither phenotype affected IFNγ+TNFα pre-stimulated cartilage, in which an inflammatory gene response was deliberately induced. CONCLUSION: M(IFNγ+TNFα) macrophages have a prominent direct effect on OA cartilage, while M(IL-4) and M(IL-10) do not inhibit the effects of M(IFNγ+TNFα), or IFNγ+TNFα induced inflammation of the cartilage. Therapies aiming at inhibiting cartilage degeneration may take this into account by directing suppression of pro-inflammatory macrophages or stimulation of anti-inflammatory macrophages.