Project description:Objective: Fibronectin is a matrix protein that is fragmented during cartilage degradation in osteoarthritis (OA). Treatment of chondrocytes with fibronectin fragments (FN-f) has been used to model OA in vitro, but the system has not been fully characterized. This study sought to define the transcriptional response of chondrocytes to FN-f, and directly compare it to responses traditionally observed in OA. Design: Normal human femoral chondrocytes isolated from tissue donors were treated with either FN-f or PBS (control) for 3, 6, or 18 hours. RNA-seq libraries were compared between time-matched FN-f and control samples in order to identify changes in gene expression over time. Differentially expressed genes were compared to a published OA gene set and used for pathway, transcription factor motif, and kinome analysis. Results: FN-f treatment resulted in 3,914 differentially expressed genes over the time course. Genes that are up- or downregulated in OA were significantly up- (p < 0.00001) or downregulated (p < 0.0004) in response to FN-f. Early response genes were involved in proinflammatory pathways, whereas many late response genes were involved in ferroptosis. The promoters of upregulated genes were enriched for NF-?B, AP-1, and IRF motifs. Highly upregulated kinases included CAMK1G, IRAK2, and the uncharacterized kinase DYRK3, while growth factor receptors TGFBR2 and FGFR2 were downregulated. Conclusions: FN-f treatment of normal human articular chondrocytes recapitulated many key aspects of the OA chondrocyte phenotype. This in vitro model is promising for future OA studies, especially considering its compatibility with genomics and genome-editing techniques.
Project description:Gene expression profiles in synovial biopsies from patients with rheumatoid arthritis (RA) display a high level of plasticity related to disease activity and response to therapy. In order to identify TNFa-dependent genes in ex vivo RA or other synovial biopsies, we generated the present set of data using primary fibroblast-like synovial cell (FLS) cultures incubated overnight in the presence or the absence of TNFa.
Project description:Background: Managing early-to-mid-stage knee osteoarthritis (OA) remains an unmet clinical need. Synovitis drives OA progression, but current anti-inflammatory therapies offer limited efficacy. Disrupted fibroblast lineage homeostasis is central in chronic inflammation, and targeting this may attenuate synovitis and pathological synovium-cartilage crosstalk in knee OA. Methods: Synovial single-cell sequencing, clinical histological and transcriptomic data assessed fibroblast lineage changes and similarities between dermal fibroblasts (DFb) and synovial fibroblasts. Labeled DFb injection in rat knees evaluated cell retention. Rat anterior cruciate ligament transection (ACLT) model with intra-articular DFb injection assessed the therapeutic efficacy. Co-cultures characterized DFb paracrine effects on synovial fibroblasts and chondrocytes. Proteomics identified active components in DFb supernatants. Results: OA synovium exhibits disrupted fibroblast lineage homeostasis, marked by a prominent pro-inflammatory phenotype in synovial fibroblasts. DFb show high transcriptomic and morphological similarity to synovial fibroblasts from healthy donors. Post-injection, DFb engrafted within the synovium with more than 3-week retention. Intra-articular DFb injection alleviated synovitis and cartilage degeneration in ACLT-induced OA rats. Co-cultures confirmed DFb alleviated cytokine-induced inflammatory responses in synovial fibroblasts and chondrocytes via paracrine mechanisms, and integrated proteomic/transcriptomic analyses identified apolipoprotein D (APOD) as a potential key mediator of these anti-inflammatory effects. Conclusions: This study validates a novel cell therapy for OA that targets disrupted fibroblast lineage homeostasis in synovitis. By modulating pro-inflammatory synovial fibroblasts and alleviating synovitis through restoring lineage homeostasis, DFb ameliorate OA progression, providing a new theoretical basis and practical approach for OA cell therapy research.
Project description:Synovial inflammation is associated with pain severity in patients with knee osteoarthritis (OA). The aim here was to determine in a population with knee OA, whether synovial tissue from areas associated with pain exhibited different synovial fibroblast subsets, compared to synovial tissue from sites not associated with pain. A further aim was to compare differences between early and end-stage disease synovial fibroblast subsets. Parapatellar synovitis was significantly associated with the pattern of patient-reported pain in knee OA patients. Synovial tissue from sites of patient-reported pain exhibited a differential transcriptomic phenotype, with distinct synovial fibroblast subsets in early OA and end-stage OA. Functional pathway analysis revealed that synovial tissue and fibroblast subsets from painful sites promoted fibrosis, inflammation and the growth and activity of neurons. The secretome of fibroblasts from early OA painful sites induced neurite outgrowth in dorsal root ganglion neurons. Sites of patient-reported pain in knee OA is associated with a different synovial tissue phenotype and distinct synovial fibroblast subsets. Further interrogation of these fibroblast pathotypes will increase our understanding of the role of synovitis in OA joint pain and provide a rationale for the therapeutic targeting of fibroblast subsets to alleviate pain in patients.
Project description:We demonstrate that JQ1 inhibits IL1B based RA Synovial Fibroblast activation and proliferation, by inhibiting key BRD2/4 superenhancer genes.
Project description:We demonstrate that JQ1 inhibits IL1B based RA Synovial Fibroblast activation and proliferation, by inhibiting key BRD2/4 superenhancer genes.
Project description:We demonstrate that JQ1 inhibits IL1B based RA Synovial Fibroblast activation and proliferation, by inhibiting key BRD2/4 superenhancer genes.