Molecular Pathology of adverse local tissue reaction caused by metal-on-metal implants
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ABSTRACT: RNA-sequencing analysis of periacetabular synovial tissue collected from patients undergoing a revision total hip arthroplasty (rTHA) after failure of a Cobalt Chromium implant. Comparisons were made to periacetabular synovial tissue collected from patients undergoing primary THAs (pTHA). Results: Analysis of tissue biopsies by RNA-sequencing revealed that MoM patient samples exhibit significantly increased expression of immune response genes but decreased expression of genes related to extracellular matrix (ECM) remodeling.
Project description:In 21 patients undergoing revision arthroplasty due to septic or aseptic implant loosening, synovial fluid was collected intraoperatively after opening the joint capsule. In a proteomic MS approach, we wanted now to investigate these synovial fluids for novel proteogenic markers of periprosthetic infections.
Project description:To investigate the physiologic responses of whole osteoarthritic synovium to cycle tensile strain. We obtained 3 matched synovial tissue samples from 6 patients undergoing total knee arthroplasty, subjected them to cyclic tensile strain, and then performed gene expression profiling analysis using RNA seq from each cyclic tensile strain protocol.
Project description:Transcriptomics of distinct subpopulations of synovial fibroblasts from osteoarthritis and rheumatoid arthritis arthroplasty tissues.
Project description:Transcriptomics of distinct subpopulations of synovial fibroblasts from osteoarthritis and rheumatoid arthritis arthroplasty tissues.
Project description:Transcriptomics of distinct subpopulations of synovial fibroblasts from osteoarthritis and rheumatoid arthritis arthroplasty tissues.
Project description:A novel ArsR-SmtB family transcriptional repressor, KmtR, has been characterised from mycobacteria. Mutants of M. tuberculosis lacking kmtR show elevated expression of Rv2025c encoding a deduced CDF-family metal-exporter. KmtR-dependent repression of the cdf and kmtR operator-promoters was alleviated by nickel and cobalt in minimal medium. Electrophoretic mobility shift assays (EMSA) and fluorescence anisotropy (FA) show binding of purified KmtR to nucleotide sequences containing a region of dyad symmetry from the cdf and kmtR operator-promoters. A relatively large deltar(obs) in FA implies formation of high order apo-KmtR(n)-DNA and multiple complexes were detected by EMSA. Incubation of KmtR with cobalt inhibits DNA-complex assembly and metal-protein binding was confirmed by competition against 4-(2-pyridylazo)-resorcinol. KmtR is the second, to NmtR, characterised ArsR-SmtB sensor of nickel and cobalt from M. tuberculosis suggesting special significance for these ions in this pathogen. KmtR-dependent expression is elevated in complete medium with no increase in response to metals, while NmtR retains a response to nickel and cobalt under these conditions. Mixing equimolar apo-KmtR and apo-NmtR with 0.8 equivalents of nickel or cobalt gave nickel- and cobalt-dependent difference emission spectra similar to nickel(0.8)-KmtR and cobalt(0.8)-KmtR, respectively. Thus, KmtR has tighter affinities for nickel and cobalt than NmtR consistent with basal levels of these metals being sensed by KmtR but not NmtR in complete medium. More than a thousand genes encoding ArsR-SmtB related proteins are listed in databases and a proportion can be predicted to detect metals through known allosteric sites. KmtR has none of the previously defined sites. Substitution of His(88), Glu(101), His(102), His(110) or His(111) with Gln generated KmtR-variants that repress the cdf and kmtR operator-promoters even in elevated nickel and cobalt, revealing a new sensory site. Importantly, ArsR-SmtB sequence groupings do not correspond with the different sensory-motifs revealing that only the latter should be used to predict metal-sensing. Data is also available from http://bugs.sgul.ac.uk/E-BUGS-49
Project description:Synovial fibroblasts in persistent inflammatory arthritis have been suggested to have parallels with cancer growth and wound healing, both of which involve a stereotypical serum response program. We tested the hypothesis that a serum response program can be used to classify diseased tissues, and investigated the serum response program in fibroblasts from multiple anatomical sites and two diseases. To test our hypothesis we utilized a bioinformatics approach to explore a publicly available microarray dataset including RA, OA and normal synovial tissue, then extended those findings in a new microarray dataset representing matched synovial, bone marrow and skin fibroblasts cultured from RA and OA patients undergoing arthroplasty. The classical fibroblast serum response program discretely classified RA, OA and normal synovial tissues. Analysis of low and high serum treated fibroblast microarray data revealed a hierarchy of control, with anatomical site the most powerful classifier followed by response to serum and then disease. In contrast to skin and bone marrow fibroblasts, exposure of synovial fibroblasts to serum led to convergence of RA and OA expression profiles. Pathway analysis revealed three inter-linked gene networks characterising OA synovial fibroblasts: Cell remodelling through insulin-like growth factors, differentiation and angiogenesis through β3 integrin, and regulation of apoptosis through CD44. We have demonstrated that Fibroblast serum response signatures define disease at the tissue level, and that an OA specific, serum dependent repression of genes involved in cell adhesion, extracellular matrix remodelling and apoptosis is a critical discriminator between cultured OA and RA synovial fibroblasts.
Project description:Osteolysis is a serious postoperative complication of total joint arthroplasty that leads to aseptic loosening and surgical revision. Osteolysis is a chronic destructive process occurs when host macrophages recognize the implant particles and release inflammatory mediators that increase bone-resorbing osteoclastic activity and attenuate bone-formation osteoblastic activity. Although much progress has been made on understanding molecular responses of macrophage to implant particles, pathways/signals initiating osteolysis remain poorly characterized. Transcriptomics and gene-expression profiling of these macrophages may unravel key mechanism in pathogenesis of osteolysis and aid in identifying molecular candidates for therapeutic intervention. To this end, we analyzed the transcriptional profiling of macrophages exposed to UHMWPE particles of the most common components used in bearing materials of orthopedic implants. Regulated genes in stimulated macrophages were involved in cytokine, chemokine, growth factor and receptor activities. Gene enrichment analysis suggested that stimulated macrophages elicited common gene expression signatures for inflammation and rheumatoid arthritis. Among the regulated genes, TNFSF15 and CCL20 were further characterized as molecular targets involved pathogenesis of osteolysis. Treatment of monocyte cultures with TNFSF15 and CCL20 resulted in an increase in osteoclastogenesis and bone-resorbing osteoclastic activity, suggesting their potential contribution to loosening between implant and bone tissue.
Project description:Synovial fibroblasts in persistent inflammatory arthritis have been suggested to have parallels with cancer growth and wound healing, both of which involve a stereotypical serum response program. We tested the hypothesis that a serum response program can be used to classify diseased tissues, and investigated the serum response program in fibroblasts from multiple anatomical sites and two diseases. To test our hypothesis we utilized a bioinformatics approach to explore a publicly available microarray dataset including RA, OA and normal synovial tissue, then extended those findings in a new microarray dataset representing matched synovial, bone marrow and skin fibroblasts cultured from RA and OA patients undergoing arthroplasty. The classical fibroblast serum response program discretely classified RA, OA and normal synovial tissues. Analysis of low and high serum treated fibroblast microarray data revealed a hierarchy of control, with anatomical site the most powerful classifier followed by response to serum and then disease. In contrast to skin and bone marrow fibroblasts, exposure of synovial fibroblasts to serum led to convergence of RA and OA expression profiles. Pathway analysis revealed three inter-linked gene networks characterising OA synovial fibroblasts: Cell remodelling through insulin-like growth factors, differentiation and angiogenesis through ?3 integrin, and regulation of apoptosis through CD44. We have demonstrated that Fibroblast serum response signatures define disease at the tissue level, and that an OA specific, serum dependent repression of genes involved in cell adhesion, extracellular matrix remodelling and apoptosis is a critical discriminator between cultured OA and RA synovial fibroblasts. Fibroblasts were isolated from synovium, bone marrow and skin tissue samples taken at the time of knee or hip replacement surgery from 12 rheumatoid arthritis patients meeting the 1987 ACR criteria and 6 osteoarthritis patients diagnosed on the basis of characteristic x-ray findings and the absence of features suggestive of inflammatory arthritis. Only one hip sample was present in either disease group. Fibroblasts were maintained in fibroblast medium (consisting of 81.3% RPMI 1640, 10% FCS, 0.81x MEM non-essential amino acids, 0.81mM sodium orthopyruvate, 1.62mM glutamine, 810U/ml penicillin and 81?g/ml streptomycin) at 37°C in a humidified 5% CO2 atmosphere.