biostudies-literatureUnknown4(1)Onnheim K<h4>Objective</h4> To investigate whether articular chondrocytes from rheumatoid arthritis (RA) patients have acquired a proinflammatory phenotype. <h4>Method</h4> Articular cartilage explants from RA patients and healthy controls (HC) were cultured with or without interleukin (IL)-1β for two weeks. Protein levels of cytokines and metalloproteinases (MMPs) in the supernatant were measured by LUMINEX, mRNA with qPCR and nitrogen oxide (NO) levels with Griess assay. <h4>Results</h4> Within 24 ​h after culture, cartilage explants from RA spontaneously produced MMP-1 and MMP-13, and matrix components (aggrecan and collagen type IV) were released. In addition, the RA explants released higher levels of tumor necrosis factor, interferon-γ, IL-33, IL-18, vascular endothelial growth factor-A, IL-6 but not IL-8, and granulocyte-macrophage colony-stimulating factor (GM-CSF) as compared with HC. During two weeks of incubation the higher levels did not diminish. IL-1β stimulation further increased the levels of IL-6, IL-8 and GM-CSF, mainly in RA explants, and induced increased levels of NO in the supernatant from both HC and RA explants, as a result of chondrocyte activation. <h4>Conclusions</h4> RA chondrocytes are activated with a proinflammatory profile involving the production of cytokines as well as MMP-1 and MMP-13, that can lead to release of matrix molecules after activation, which suggests that the chondrocytes have a proinflammatory phenotype and thereby an active role in the pathogenesis.Osteoarthritis and cartilage openhttps://www.ebi.ac.uk/biostudies/studies/S-EPMC9718183biostudies-literatureRheumatoid arthritis chondrocytes produce increased levels of pro-inflammatory proteinsPMC9718183Huang SStrid Holmertz AJonsson CAndersson SGjertsson ILonnblom EHolmdahl ROnnheim KfalseRheumatoid arthritis chondrocytes produce increased levels of pro-inflammatory proteins<h4>Objective</h4> To investigate whether articular chondrocytes from rheumatoid arthritis (RA) patients have acquired a proinflammatory phenotype. <h4>Method</h4> Articular cartilage explants from RA patients and healthy controls (HC) were cultured with or without interleukin (IL)-1β for two weeks. Protein levels of cytokines and metalloproteinases (MMPs) in the supernatant were measured by LUMINEX, mRNA with qPCR and nitrogen oxide (NO) levels with Griess assay. <h4>Results</h4> Within 24 ​h after culture, cartilage explants from RA spontaneously produced MMP-1 and MMP-13, and matrix components (aggrecan and collagen type IV) were released. In addition, the RA explants released higher levels of tumor necrosis factor, interferon-γ, IL-33, IL-18, vascular endothelial growth factor-A, IL-6 but not IL-8, and granulocyte-macrophage colony-stimulating factor (GM-CSF) as compared with HC. During two weeks of incubation the higher levels did not diminish. IL-1β stimulation further increased the levels of IL-6, IL-8 and GM-CSF, mainly in RA explants, and induced increased levels of NO in the supernatant from both HC and RA explants, as a result of chondrocyte activation. <h4>Conclusions</h4> RA chondrocytes are activated with a proinflammatory profile involving the production of cytokines as well as MMP-1 and MMP-13, that can lead to release of matrix molecules after activation, which suggests that the chondrocytes have a proinflammatory phenotype and thereby an active role in the pathogenesis.2022-01-01T00:00:00Z2022 Jan2025-04-26T20:48:32.527Z2025-04-06T16:32:27.955ZS-EPMC9718183