No description available.

Macrophages are an important cell type well known for its’ role in the immune system. Macrophages have two hematopoietic sources; they can be derived from hematopoietic stem cell (HSC) progenitors or erythro-myeloid progenitors (EMP). Synovial macrophages exist within the normal healthy joint, but the current origins and functions of these cells are unclear, including those involved in inflammatory arthritis (IA). To explore the origins of the synovial macrophages we utilized both cell lineage-tracing models and an arthritic model, K/BxN mice serum transfer arthritis (STA). We used Flt3Cre;Rosa26LSL-YFP mice to label HSC-derived cells and Cx3cr1CreERT2;Rosa26LSL-tdTomato and CSF1rmericremer;Rosa26LSL-tdTomato mice to label EMP-derived cells. Our histological data showed a unique population of EMP derived synovial tissue resident macrophages that was present in mice at ages E16.5 and P0 (neonate). Additionally, we found that HSC-derived cells do not significantly contribute to synovial macrophage populations throughout development. Interestingly, in arthritic conditions, we detected a dramatic increase in HSC-derived synovial macrophages in the inflamed synovium. Using macrophage markers F4/80 and CD68 we were able to fluorescently label and identify three different subtypes of synovial macrophages that exist within the joint in both homeostatic and arthritic conditions. Although further studies need to be completed, we have taken a pivotal step towards characterizing synovial macrophages in healthy and arthritic mice.

No description available.

Rheumatoid arthritis (RA) is a chronic inflammatory disease of autoimmune origin affecting approximately 1% of adult population worldwide. The clinical course of RA is highly variable, ranging from self-limiting to severe disease, with considerable individual and socio-economic implications. It is now well acknowledged that early diagnosis and treatment equates to better long-term outcomes. However, despite major therapeutic advances in recent decades, the management of RA remains challenging as a significant proportion of patients presents with active disease despite maximization of therapy. It is also difficult to predict which patients will respond adequately to various treatment regimens. The identification of biomarkers of clinical outcome capable of stratifying patients into accurate prognostic categories and guide pharmacological intervention is therefore urgently needed. Notably, along with clinical variability, RA is characterised by high biological heterogeneity at the tissue level. The cellular infiltrate of the RA synovium can be distinguished into at least three main patterns according to the degree and organisation of the immune cells: the 'Lymphoid' pattern characterised by predominant B and T lymphocytes which tend to cluster in discrete aggregates resembling ectopic lymphoid structures; the 'Myeloid' pattern characterised by absence of lymphocytic aggregates but significant expression of sublining macrophages; the 'Pauci-immune' pattern, that hardly shows any infiltrating immune cells. The hypothesis of this thesis was to determine whether these distinct synovial pathotypes may define specific disease subsets and predict response to therapy in patients with RA. Specifically, this work aims at: 1. evaluating whether the synovial pathotype associates with the presence of specific clinical, serological, radiological and ultrasonographic findings in an early RA cohort (< 1 year onset); 2. exploring the potential role of the synovial pathotype as a predictor of response to conventional synthetic disease-modifying antirheumatic drugs (csDMARD) after 6 months in an early RA cohort; 3. exploring the potential role of the synovial pathotype as a predictor of response to anti-TNFα treatment after 3 months in a csDMARD-failure established RA cohort.

No description available.

Rheumatoid arthritis (RA) is a chronic, systemic inflammatory disorder that may affect many tissues and organs but principally attacks synovial joints. All the symptoms of RA are mainly caused by cell inflammation, which results in cellular infiltration and synovial hyperplasia, finally leading to severe bone erosion. Existing drugs (steroids, non-steroid antiinflammatory drugs, disease-modifying anti-rheumatic drugs, etc.) can attenuate the symptoms of RA; however, these drugs also have many side effects. Therefore, it is necessary to discover new drugs for RA. Excavatolide B (Exc-B) is derived from the gorgonian coral. In our preliminary observations, Exc-B strongly inhibited lipopolysaccharide (LPS)-induced proinflammatory inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expression in RAW264.7 macrophages. The present study also showed that Exc-B significantly attenuates the expressions of osteoclast-like gene, cathepsin K, and matrix metalloproteinase (MMP)-9 in LPS-treated RAW 264.7 cells. Moreover, in the adjuvant-induced RA animal model, Exc-B effectively reduced the swelling and arthritic index from the morphological viewpoint as well as reduced bone erosion and synovial hyperplasia from the pathological viewpoint. Our data indicates that Exc-B can inhibit disease progression in RA. Hence, Exc-B may serve as a useful therapeutic agent for the treatment of RA.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第24829号 / 医博第4997号 / 新制||医||1067(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 森信, 暁雄, 教授 竹内, 理, 教授 濵﨑, 洋子 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Dorsoradial and anterior oblique ligaments were harvested during surgery in 13 patients with symptomatic trapeziometacarpal osteoarthritis, which had been graded preoperatively by a modified Eaton-Littler radiographic grading. Ligaments, including the periligamentous synovium, were stained with S100 protein, neurotrophic receptor p75, protein gene product 9.5, calcitonin gene related peptide, acetylcholine, substance P, neuropeptide Y, noradrenaline, N-methyl-D-aspartate-receptor and Met/Leu-enkephalin. The synovium was classified as showing no, low-grade or high-grade synovitis. Free nerve endings had higher immunoreactivity for substance P than for N-methyl-D-aspartate-receptor, enkephalin and noradrenaline. The synovial stroma had less immunoreactivity for N-methyl-D-aspartate-receptor than for noradrenaline, substance P and calcitonin gene related peptide. There was no relation between the grade of osteoarthritis and the visual pain analogue scale, synovitis score, immunoreactivity of all antibodies and quantity of free nerve endings or blood vessels. Synovium in trapeziometacarpal joint osteoarthritis produces several neuromediators causing a polymodal neurogenic inflammation and which may serve as biomarkers for osteoarthritis or therapeutic targets.

Rheumatoid arthritis (RA) is a chronic inflammatory disease affecting 1% of the population. The aetiology of rheumatoid arthritis is unknown, although there are multiple postulated theories. In 1950, Philip Hench won the Nobel prize for treating patients with rheumatoid arthritis with cortisone. He also treated 6 patients with adrenocorticotropic hormone (ACTH) with good results. ACTH is a melanocortin. The melanocortin system describes the five melanocortin receptors, their ligands, agonists and antagonists and the accessory proteins. The aim of this study was to explore the melanocortin receptors in rheumatoid arthritis synovium. Methods HA-tagged stable cell lines were created for MC1R, MC3R and MC5R. Multiple antibodies were tested for their utility using Western Blot, immunohistochemistry and flow cytometry. Samples of synovium from 28 patients with RA were tested using RTPCR for the presence of MC1R and MC3R. Gene expression was correlated with clinical characteristics, cytokine (RTPCR) expression and immunohistochemical score. Results The stable cell lines expressed MC1R, MC3R and MC5R respectively. Of the antibodies tested none were found to be of utility in detecting MC1R or MC3R .The MC1R RQ values in rheumatoid synovium appear to split into two groups, high and low. The medians of the two groups are significantly different (p=0.0005). There is almost a 5 cycle, or 64 fold, difference in gene expression between the medians of the two groups (1.59 v 6.23). Of note no MC3R positive samples were CD138 high (i.e. no MC3R positive samples had a significant plasma cell infiltrate) (p=0.006). Categorical analysis using Fishers Exact test revealed an association between MC1R high samples and CD68 lining high scores, (i.e. MC1R high samples also had a high macrophage score in the lining of the sample) (p=0.02). MC1R low samples were associated with not being on combination therapy, 15 this did not quite reach significance (p=0.07). Linear regression analysis confirmed these associations for MC1R. PCA analysis did not show any grouping of samples according to any of the variables tested, likely due to sample size. Conclusion MC1R and MC3R are found in human synovium. Current commercial antibodies are not of utility in detecting MC1R or MC3R. Synovial samples can be split into high and low MC1R gene expression groups. MC3R was either present or absent. High expression of MC1R was associated with a high macrophage score and MC3R expression was associated with a low plasma cell score. MC1R and MC3R expression in RA synovium could be used as biomarkers of disease state or severity as well as a target for therapy.

Rheumatoid arthritis (RA) is a chronic, inflammatory autoimmune disease that targets joints, resulting in in permanent disability. Synovial macrophages have been implicated in the pathogenesis of RA; however, their exact origins and functions remains unclear. In this study, we show evidence that synovial macrophages are mostly derived from embryonic origin during normal development. Macrophages are derived from either hematopoietic stem cells (HSC) or erythro-myeloid progenitors (EMP), and it is postulated that different subpopulations of synovial macrophages may have distinct functions contributing to either homeostasis or inflammation. To investigate the phenotypes of synovial macrophage populations and characterize their lineage-specific functions in arthritic joints, we utilized both cell lineage-tracing and K/BxN serum-transfer arthritis mouse models. Utilizing Flt3Cre;Rosa26LSL-YFP mice to label HSC-derived cells, we demonstrated that there is minimal HSC contribution to synovial macrophage populations during homeostasis. Use of RankCre;Rosa26LSL-YFP and Cx3cr1CreERT2;Rosa26LSL-tdTomato mice to label EMP-derived cells corroborated the finding that the EMP compartment maintains the largest contribution to synovial macrophage populations during normal development. Analysis of macrophages in Csf1rMericreMer;Rosa26-LSLtdTomato mice provided definitive prove that synovial macrophages derived from yolk-sac EMP precursors in adult mice. Use of serum transfer arthritis (STA) mice demonstrated that while most macrophages in the inflamed synovium were EMP-derived, there was a marked increase in HSC-derived cells compared to those present in homeostasis. Although this study has contributed to eluding that the heterogeneity of synovial macrophages in both homeostasis and inflammatory arthritis (IA) is complex and lineage-specific, further studies are needed to clearly define lineage-specific functions of macrophages in synovial tissues and in IA.