Georg Schett

Universitätsklinikum Erlangen, Erlangen, Bavaria, Germany

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Publications (447)3166.86 Total impact

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    ABSTRACT: Autophagy has recently been shown to regulate osteoclast activity and osteoclast differentiation. Here, we aim to investigate the impact of autophagy inhibition as a potential therapeutic approach for the treatment of osteoporosis in preclinical models. Systemic bone loss was induced in mice by glucocorticoids and by ovariectomy (OVX). Autophagy was targeted by conditional inactivation of autophagy-related gene 7 (Atg7) and by treatment with chloroquine (CQ). Bone density was evaluated by microCT. The role of autophagy on osteoclastogenesis was analysed by osteoclastogenesis and bone resorption assays. The quantification of receptor activator of nuclear factor κ B ligand and osteoprotegerin proteins in cocultures was performed using ELISA whereas that of osteoclast and osteoblast differentiation markers was by qPCR. Selective deletion of Atg7 in monocytes from Atg7(fl/fl)_x_LysM-Cre mice mitigated glucocorticoid-induced and OVX-induced osteoclast differentiation and bone loss compared with Atg7(fl/fl) littermates. Pharmacological inhibition of autophagy by treatment with CQ suppressed glucocorticoid-induced osteoclastogenesis and protected mice from bone loss. Similarly, inactivation of autophagy shielded mice from OVX-induced bone loss. Inhibition of autophagy led to decreased osteoclast differentiation with lower expression of osteoclast markers such as NFATc1, tartrate-resistant acid phosphatase, OSCAR and cathepsin K and attenuated bone resorption in vitro. In contrast, osteoblast differentiation was not affected by inhibition of autophagy. Pharmacological or genetic inactivation of autophagy ameliorated glucocorticoid-induced and OVX-induced bone loss by inhibiting osteoclastogenesis. These findings may have direct translational implications for the treatment of osteoporosis, since inhibitors of autophagy such as CQ are already in clinical use. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
    Annals of the rheumatic diseases 06/2015; DOI:10.1136/annrheumdis-2015-207240 · 9.27 Impact Factor
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    ABSTRACT: In order to investigate the characteristics of anti-ß2GP1 autoantibodies that determine pathogenicity in the antiphospholipid syndrome, we analysed sera from healthy children harbouring anti-ß2GP1 autoantibodies and from patients with antiphospholipid syndrome (APS). Healthy donors served as controls. We performed ELISAs to quantify the levels of anti-ß2GP1-IgM, anti-ß2GP1-IgG and its subclasses. Furthermore, we investigated the complement factors C1q and C3c bound to the anti-ß2GP1 antibodies. To analyse the glycosylation of anti-ß2GP1, we investigated purified IgG from healthy children, patients with APS and asymptomatic adult carriers of anti-phospholipid antibodies. We observed that in the sera of healthy children and of patients with APS, IgG3 and IgG2 were predominant, respectively. The potentially protective anti-ß2GP1-IgM was even lower in the sera of healthy children. Although anti-ß2GP1-associated C1q did not differ between children and patients with antiphospholipid syndrome, the associated C3c was significantly higher in the sera of healthy children. This indicates a more efficient clearance of anti-ß2GP1 immune complexes in the healthy children. Obviously, this clearance is not accompanied by inflammation and coagulatory events. It is likely that the most important pathogenic factor of the anti-ß2GP1-IgG is related to the different glycosylation observed in healthy and diseased individuals. We detected a significantly higher sialylation of anti-ß2GP1-IgG isolated from the sera of healthy children and asymptomatic adults when compared with that of patients with clinically apparent antiphospholipid syndrome. Low sialylated IgG reportedly ameliorates inflammation and inflammation promotes hyposialylation. Thus, both reactions form a vicious circle that precipitates the pathogenicity of the antiphospholipid syndrome including thrombus-formation. We conclude that the increased sialylation of anti-ß2GP1-IgG of sera of healthy individuals limits their pathogenic potential.
    Journal of Immunology Research 06/2015; 2015(Article ID 638129):12. DOI:10.1155/2015/638129 · 2.93 Impact Factor
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    ABSTRACT: Chronic peripheral inflammation mediated by cytokines such as TNFα, IL-1β, and IL-6 is associated with psychiatric disorders like depression and anxiety. However, it remains elusive which distinct type of peripheral inflammation triggers neuroinflammation and affects hippocampal plasticity resulting in depressive-like behavior. We hypothesized that chronic peripheral inflammation in the human TNF-α transgenic (TNFtg) mouse model of rheumatoid arthritis spreads into the central nervous system and induces depressive state manifested in specific behavioral pattern and impaired adult hippocampal neurogenesis. TNFtg mice showed severe erosive arthritis with increased IL-1β and IL-6 expression in tarsal joints with highly elevated human TNF-α levels in the serum. Intriguingly, IL-1β and IL-6 mRNA levels were not altered in the hippocampus of TNFtg mice. In contrast to the pronounced monocytosis in joints and spleen of TNFtg mice, signs of hippocampal microgliosis or astrocytosis were lacking. Furthermore, locomotion was impaired, but there was no locomotion-independent depressive behavior in TNFtg mice. Proliferation and maturation of hippocampal neural precursor cells as well as survival of newly generated neurons were preserved in the dentate gyrus of TNFtg mice despite reduced motor activity and peripheral inflammatory signature. We conclude that peripheral inflammation in TNFtg mice is mediated by chronic activation of the innate immune system. However, severe peripheral inflammation, though impairing locomotor activity, does not elicit depressive-like behavior. These structural and functional findings indicate the maintenance of hippocampal immunity, cellular plasticity, and behavior despite peripheral innate inflammation. Copyright © 2015. Published by Elsevier Inc.
    Brain Behavior and Immunity 06/2015; DOI:10.1016/j.bbi.2015.05.011 · 6.13 Impact Factor
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    ABSTRACT: Osteoarthritis is not only characterized by cartilage degradation but also involves subchondral bone remodeling and osteophyte formation. Osteophytes are fibrocartilage-capped bony outgrowths originating from the periosteum. The pathophysiology of osteophyte formation is not completely understood. Yet, different research approaches are under way. Therefore, a histological osteophyte classification to achieve comparable results in osteophyte research was established for application to basic science research questions. The osteophytes were collected from knee joints of osteoarthritis patients (n=10, 94 osteophytes in total) after joint replacement surgery. Their size and origin in the respective joint were photo-documented. To develop an osteophyte classification, serial tissue sections were evaluated using histological (hematoxylin and eosin, Masson's trichrome, toluidine blue) and immunohistochemical staining (collagen type II). Based on the histological and immunohistochemical evaluation, osteophytes were categorized into four different types depending on the degree of ossification and the percentage of mesenchymal connective tissue. Size and localization of osteophytes were independent from the histological stages. This histological classification system of osteoarthritis osteophytes provides a helpful tool for analyzing and monitoring osteophyte development and for characterizing osteophyte types within a single human joint and may therefore contribute to achieve comparable results when analyzing histological findings in osteophytes. Copyright © 2015 Société française de rhumatologie. Published by Elsevier SAS. All rights reserved.
    Joint, bone, spine: revue du rhumatisme 06/2015; DOI:10.1016/j.jbspin.2015.04.008 · 3.22 Impact Factor
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    ABSTRACT: Clustering of surface receptors is often required to initiate signal transduction, receptor internalization, and cellular activation. To study the kinetics of clustering, we developed an economic high-throughput method using flow cytometry. The quantification of receptor clustering by flow cytometry is based on the following two observations: first, the fluorescence signal length (FL time-of-flight [ToF]) decreases relative to the forward scatter signal length (FSc-ToF), and second, the peak FL (FL-peak) increases relative to the integral FL (FL-integral) upon clustering of FL-labeled surface receptors. Receptor macroclustering can therefore be quantified using the ratios FL-ToF/FSc-ToF (method ToF) or FL-peak/FL-integral (method Peak). We have used these methods to analyze clustering of two immune receptors known to undergo different conformational and oligomeric states: the BCR and the complement receptor 3 (CR3), on murine splenocytes, purified B cells, and human neutrophils. Engagement of both the BCR and CR3, on immortalized as well as primary murine B cells and human neutrophil, respectively, resulted in decreased FL-ToF/FSc-ToF and increased FL-peak/FL-integral ratios. Manipulation of the actin-myosin cytoskeleton altered BCR clustering which could be measured using the established parameters. To confirm clustering of CR3 on neutrophils, we applied imaging flow cytometry. Because receptor engagement is as a biological process dependent on cell viability, energy metabolism, and temperature, receptor clustering can only be quantified by gating on viable cells under physiological conditions. In summary, with this novel method, receptor clustering on nonadherent cells can easily be monitored by high-throughput conventional flow cytometry. Copyright © 2015 by The American Association of Immunologists, Inc.
    The Journal of Immunology 05/2015; DOI:10.4049/jimmunol.1401889 · 5.36 Impact Factor
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    ABSTRACT: Molecular and clinical observations provide evidence for a potential role of parathyroid hormone (PTH) in colorectal cancer development. We therefore aimed to assess the association of PTH with regard to colorectal cancer precursor lesions. A cohort of 1432 participants, 777 men, 58.4 ± 9.6 years and 701 women, 59.1 ± 10.6 years, undergoing screening colonoscopy were allocated to PTH serum concentrations either above or below 55 ng/L. The number, localization, size, and histology of the polypoid lesions detected during screening colonoscopy were recorded according to PTH serum concentrations. Serum PTH concentrations were not different between men and women. Women with PTH serum concentrations above the cut-off had significantly more adenomas (13/40; 32.5 %) of the distal colon compared to women below the cut-off (91/659; 13.8 %; P = 0.001). Additionally, the rate of dysplasia in adenomas of the distal colon was higher in women with high compared to low PTH concentrations (P = 0.001). These findings remained robust after adjustments for serum vitamin D, age, plasma creatinine, BMI, diabetes, and liver steatosis. No associations were observed between serum PTH concentrations and colorectal lesions in men. These data suggest that elevated PTH serum concentrations might have a role in colorectal cancer development as indicated by higher rates of adenomas, specifically with dysplasia, in women. The role of PTH in colon carcinogenesis and its sex specificity deserve further study.
    Hormones and Cancer 05/2015; 6(4). DOI:10.1007/s12672-015-0227-0 · 2.15 Impact Factor
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    ABSTRACT: Neutrophil granulocytes possess a large arsenal of pro-inflammatory substances and mechanisms that empower them to drive local acute immune reactions to invading microorganisms or endogenous inflammatory triggers. The use of this armory needs to be tightly controlled to avoid chronic inflammation and collateral tissue damage. In gout, inflammation arises from precipitation of uric acid in the form of needle-shaped monosodium urate crystals. Inflammasome activation by these crystals in local immune cells results in a rapid and dramatic recruitment of neutrophils. This neutrophil influx is accompanied by the infamously intense clinical symptoms of inflammation during an acute gout attack. Neutrophilic inflammation however is equipped with a built-in safeguard; activated neutrophils form neutrophil extracellular traps (NETs). At the very high neutrophil densities that occur at the site of inflammation, NETs build aggregates that densely pack the monosodium urate (MSU) crystals and trap and degrade pro-inflammatory mediators by inherent proteases. Local removal of cytokines and chemokines by aggregated NETs explains how acute inflammation can stop in the consistent presence of the inflammatory trigger. Aggregated NETs resemble early stages of the typical large MSU deposits that constitute the pathognomonic structures of gout, tophi. Although tophi contribute to muscosceletal damage and mortality in patients with chronic gout, they can therefore be considered as a payoff that is necessary to silence the intense inflammatory response during acute gout.
    Journal of Molecular Medicine 05/2015; 93(7). DOI:10.1007/s00109-015-1295-x · 4.74 Impact Factor
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    ABSTRACT: TNF-α drives bone destruction but also inhibits new bone formation by inducing Dkk-1, an inhibitor of the Wnt pathway. Accordingly, blocking Dkk-1 reverses the bone-destructive phenotype to a bone-forming pattern in experimental arthritis. To delineate the potential role of Dkk-1 in the structural phenotype of human arthritis, we analyzed the expression of Dkk-1 and its regulation by pro-inflammatory cytokines in spondyloarthritis (SpA) versus rheumatoid arthritis (RA) inflamed peripheral joints. Expression of Dkk-1 and pro-inflammatory cytokines was determined by ELISA and microarray in synovial fluid (SF) and tissue, respectively. Regulation of Dkk-1 production by pro-inflammatory cytokines was assessed in fibroblast-like synoviocytes (FLS) cultures. TNF-α and IL-1β, but not IL-6, levels were significantly higher in RA than SpA SF (p<0.001 for both). SF levels of Dkk-1 were similar in SpA and RA, and did not correlated with TNF-α and IL-1β levels. However, Dkk-1 showed an inverse correlation with IL-6 levels in both SpA (r =-0.31; p=0.04) and RA SF (r=-0.39; p=0.01), which was reproduced at the mRNA levels in synovial tissue. In vitro experiments with FLS confirmed that Dkk-1 production was strongly induced by TNF-α but clearly suppressed by IL-6. Moreover, IL-6 was able to suppress the TNF-α-induced upregulation of Dkk-1 production by FLS. The inverse correlation of Dkk-1 with IL-6 levels observed in vivo in the inflamed joints was mirrored by the differential regulation of Dkk-1 production by TNF-α and IL-6 in vitro. The relative balance between these and other factors in the arthritic joints may determine functional Wnt signalling and tissue remodelling. This article is protected by copyright. All rights reserved. © 2015, American College of Rheumatology.
    05/2015; DOI:10.1002/art.39183
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    ABSTRACT: To investigate the prevalence of knee US findings of inflammation and structural damage in aged individuals (≥60 years) of a long-term population-based cohort and to correlate these findings with demographic, clinical and laboratory parameters. Cross-sectional clinical and US investigation of both knee joints during the 2010 follow-up of the prospective population-based Bruneck Study. Demographic variables, physical activity, comorbidities, medications, pain, and functional scales related to the knee joints were recorded. US-assessed parameters were synovial hypertrophy, power Doppler signal, joint effusion, cartilage abnormalities, osteophytes, enthesopathy and bursitis. Statistics included univariate and multivariate regression analysis. A total of 488 subjects (mean age 72.5 years; 53.5% females, 46.5% males) were examined by clinical assessment, and 433 of these underwent US examination of both knees. Both inflammatory and structural abnormalities were found in 296 (68.8%) subjects. Inflammatory abnormalities were significantly associated with age in years, male gender, diabetes and the presence of knee joint symptoms. In the multivariate analysis, age, male gender and knee swelling emerged as independent predictors of inflammation [odds ratio (OR) (95% CI) = 1.06 (1.03, 1.09), 2.55 (1.55, 4.21) and 5.92 (1.99, 17.58), respectively]. The present study showed a high prevalence of US inflammatory abnormalities in the knee joints of a normal aged population. These data suggest a substantial contribution of inflammation in progressive impairment of joint function with age. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
    Rheumatology (Oxford, England) 04/2015; DOI:10.1093/rheumatology/kev032 · 4.44 Impact Factor
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    ABSTRACT: Nintedanib is a tyrosine kinase inhibitor that has recently been shown to slow disease progression in idiopathic pulmonary fibrosis in two replicate phase III clinical trials. The aim of this study was to analyse the antifibrotic effects of nintedanib in preclinical models of systemic sclerosis (SSc) and to provide a scientific background for clinical trials in SSc. The effects of nintedanib on migration, proliferation, myofibroblast differentiation and release of extracellular matrix of dermal fibroblasts were analysed by microtitre tetrazolium and scratch assays, stress fibre staining, qPCR and SirCol assays. The antifibrotic effects of nintedanib were evaluated in bleomycin-induced skin fibrosis, in a murine sclerodermatous chronic graft-versus-host disease model and in tight-skin-1 mice. Nintedanib dose-dependently reduced platelet-derived growth factor-induced and transforming growth factor-β-induced proliferation and migration as well as myofibroblast differentiation and collagen release of dermal fibroblasts from patients with and healthy individuals. Nintedanib also inhibited the endogenous activation of SSc fibroblasts. Nintedanib prevented bleomycin-induced skin fibrosis in a dose-dependent manner and was also effective in the treatment of established fibrosis. Moreover, treatment with nintedanib ameliorated fibrosis in the chronic graft-versus-host disease model and in tight-skin-1 mice in well-tolerated doses. We demonstrate that nintedanib effectively inhibits the endogenous as well as cytokine-induced activation of SSc fibroblasts and exerts potent antifibrotic effects in different complementary mouse models of SSc. These data have direct translational implications for clinical trials with nintedanib in SSc. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
    Annals of the rheumatic diseases 04/2015; DOI:10.1136/annrheumdis-2014-207109 · 9.27 Impact Factor
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    ABSTRACT: DCs are able to undergo rapid maturation, which subsequently allows them to initiate and orchestrate T cell-driven immune responses. DC maturation must be tightly controlled in order to avoid random T cell activation and development of autoimmunity. Here, we determined that 12/15-lipoxygenase-meditated (12/15-LO-mediated) enzymatic lipid oxidation regulates DC activation and fine-tunes consecutive T cell responses. Specifically, 12/15-LO activity determined the DC activation threshold via generation of phospholipid oxidation products that induced an antioxidative response dependent on the transcription factor NRF2. Deletion of the 12/15-LO-encoding gene or pharmacologic inhibition of 12/15-LO in murine or human DCs accelerated maturation and shifted the cytokine profile, thereby favoring the differentiation of Th17 cells. Exposure of 12/15-LO-deficient DCs to 12/15-LO-derived oxidized phospholipids attenuated both DC activation and the development of Th17 cells. Analysis of lymphatic tissues from 12/15-LO-deficient mice confirmed enhanced maturation of DCs as well as an increased differentiation of Th17 cells. Moreover, experimental autoimmune encephalomyelitis in mice lacking 12/15-LO resulted in an exacerbated Th17-driven autoimmune disease. Together, our data reveal that 12/15-LO controls maturation of DCs and implicate enzymatic lipid oxidation in shaping the adaptive immune response.
    The Journal of clinical investigation 04/2015; 125(5). DOI:10.1172/JCI78490 · 13.77 Impact Factor
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    ABSTRACT: Immunglobulin G (IgG) sialylation represents a key checkpoint that determines the engagement of pro- or anti-inflammatory Fcγ receptors (FcγR) and the direction of the immune response. Whether IgG sialylation influences osteoclast differentiation and subsequently bone architecture has not been determined yet, but may represent an important link between immune activation and bone loss. Here we demonstrate that desialylated, but not sialylated, immune complexes enhance osteoclastogenesis in vitro and in vivo. Furthermore, we find that the Fc sialylation state of random IgG and specific IgG autoantibodies determines bone architecture in patients with rheumatoid arthritis. In accordance with these findings, mice treated with the sialic acid precursor N-acetylmannosamine (ManNAc), which results in increased IgG sialylation, are less susceptible to inflammatory bone loss. Taken together, our findings provide a novel mechanism by which immune responses influence the human skeleton and an innovative treatment approach to inhibit immune-mediated bone loss.
    Nature Communications 03/2015; 6:6651. DOI:10.1038/ncomms7651 · 10.74 Impact Factor
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    ABSTRACT: To investigate whether MRI allows the detection of osteosclerosis as a sign of repair of bone erosions compared with high-resolution peripheral quantitative computed tomography (HR-pQCT) as a reference and whether the presence of osteosclerosis on HR-pQCT is linked to synovitis and osteitis on MRI. A total of 103 RA patients underwent HR-pQCT and MRI of the dominant hand. The presence and size of erosions and the presence and extent (grades 0-2) of osteosclerosis were assessed by both imaging modalities, focusing on MCP 2 and 3 and wrist joints. By MRI, the presence and grading of osteitis and synovitis were assessed according to the Rheumatoid Arthritis MRI Score (RAMRIS). Parallel evaluation was feasible by both modalities on 126 bone erosions. Signs of osteosclerosis were found on 87 erosions by HR-pQCT and on 22 by MRI. False-positive results (MRI(+)CT(-)) accounted for 3%, while false-negative results (MRI(-)CT(+)) accounted for 76%. MRI sensitivity for the detection of osteosclerosis was 24% and specificity was 97%. The semi-quantitative scoring of osteosclerosis was reliable between MRI and HR-pQCT [intraclass correlation coefficient 0.917 (95% CI 0.884, 0.941), P < 0.001]. The presence of osteosclerosis on HR-pQCT showed a trend towards an inverse relationship to the occurrence and extent of osteitis on MRI [χ(2)(1) = 3.285; ϕ coefficient = -0.124; P = 0.070] but not to synovitis [χ(2)(1) = 0.039; ϕ coefficient = -0.14; P = 0.844]. MRI can only rarely detect osteosclerosis associated with bone erosions in RA. Indeed, the sensitivity compared with HR-pQCT is limited, while the specificity is high. The presence of osteitis makes osteosclerosis more unlikely, whereas the presence of synovitis is not related to osteosclerosis. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
    Rheumatology (Oxford, England) 03/2015; DOI:10.1093/rheumatology/kev031 · 4.44 Impact Factor
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    ABSTRACT: Stimulators of the soluble guanylate cyclase (sGC) have recently been shown to inhibit transforming growth factor-β signalling. Here, we aimed to demonstrate that riociguat, the drug candidate for clinical trials in systemic sclerosis (SSc), is effective in experimental fibrosis and to compare its efficacy to that of phosphodiesterase V inhibitors that also increase the intracellular levels of cyclic guanosine monophosphate. The antifibrotic effects of riociguat and sildenafil were compared in the tight-skin 1 model, in bleomycin-induced fibrosis and in a model of sclerodermatous chronic graft-versus-host-disease (cGvHD). Doses of 0.1-3 mg/kg twice a day for riociguat and of 3-10 mg/kg twice a day for sildenafil were used. Riociguat dose-dependently reduced skin thickening, myofibroblast differentiation and accumulation of collagen with potent antifibrotic effects at 1 and 3 mg/kg. Riociguat also ameliorated fibrosis of the gastrointestinal tract in the cGvHD model. The antifibrotic effects were associated with reduced phosphorylation of extracellular signal-regulated kinases. Sildenafil at doses of 3 and 10 mg/kg exerted mild antifibrotic effects that were significantly less pronounced compared with 1 and 3 mg/kg riociguat. These data demonstrated potent antifibrotic effects of riociguat on experimental skin and organ fibrosis. These findings suggest a role for riociguat for the treatment of fibrotic diseases, especially for the treatment of SSc. A phase II study with riociguat in patients with SSc is currently starting. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
    Annals of the rheumatic diseases 03/2015; DOI:10.1136/annrheumdis-2014-206809 · 9.27 Impact Factor
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    ABSTRACT: Fc-gamma receptors (FcγRs) have been shown to play a crucial role in cartilage degradation during experimental arthritis. Although most of their effect on cartilage degradation has been attributed to their potential to promote inflammation in the presence of immunoglobulins, activating FcγRs promote cartilage degeneration in antigen-induced arthritis (AIA) independently of the level of inflammation. This prompted us to investigate, whether FcγRs may also play a role in osteoarthritis-related cartilage degradation. FcγR expression was measured by RT-PCR and FACS in murine cartilage tissue and chondrocytes. Experimental osteoarthritis was induced by destabilisation of the medial meniscus (DMM) in WT mice and animals lacking either activating (Fc receptor γ-chain-deficient) or inhibitory (FcγRIIB-deficient) FcγRs. Cartilage damage was investigated histologically 8 weeks post-surgery by assessing proteoglycan loss and structural damage according to OARSI recommendations. Osteophyte size was measured to investigate alterations in bone turnover. Expression analyses revealed significant levels for all four types of murine FcγRs in mouse chondrocytes and cartilage tissue from newborn and 8-week-old mice. Surprisingly, yet, ablation of either activating or inhibitory FcγRs did not affect cartilage damage or bone turnover during DMM-induced osteoarthritis in mice. While FcγRs appear to have a crucial role in cartilage degradation during inflammatory arthritis our data indicate that FcγRs do not influence cartilage destruction in experimental osteoarthritis. This indicates that a certain threshold of inflammation is a prerequisite for FcγR-induced cartilage destruction in arthritis. Copyright © 2015 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.
    Osteoarthritis and Cartilage 03/2015; 23(7). DOI:10.1016/j.joca.2015.02.019 · 4.66 Impact Factor
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    ABSTRACT: Psoriatic arthritis (PsA) is a chronic inflammatory disease characterized by periarticular bone loss and new bone formation. Current data regarding systemic bone loss and bone mineral density (BMD) in PsA are conflicting. The aim of this study was to evaluate bone microstructure and volumetric BMD in patients with PsA and psoriasis. We performed HR-pQCT scans at the ultradistal and periarticular radius in 50 PsA patients, 30 psoriasis patients and 70 healthy, age- and sex-related controls assessing trabecular bone volume (BV/TV), trabecular number (Tb.N), inhomogeneity of the trabecular network, cortical thickness (Ct.Th) and cortical porosity (Ct.Po) as well as volumetric BMD. Trabecular BMD (Tb.BMD, p = 0.021, 12.0%), BV/TV (p = 0.020, -11.9%) and Tb.N (p = 0.035, 7.1%) were significantly decreased at the ultradistal radius and the periarticular radius in PsA patients compared to controls. In contrast, bone architecture of the ultradistal radius and periarticular radius was similar in patients with psoriasis and healthy controls. Duration of skin disease was associated with low BV/TV and Tb.N in patients with PsA. These data suggest that trabecular BMD and bone microstructure are decreased in PsA patients. The observation that duration of skin disease determines bone loss in PsA supports the concept of subclinical musculoskeletal disease in psoriasis patients. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 03/2015; DOI:10.1002/jbmr.2521 · 6.59 Impact Factor
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    ABSTRACT: To investigate whether bortezomib, a proteasome inhibitor approved for treatment of multiple myeloma, induces clinically relevant plasma cell (PC) depletion in patients with active, refractory systemic lupus erythematosus (SLE). Twelve patients received a median of two (range 1-4) 21-day cycles of intravenous bortezomib (1.3 mg/m(2)) with the coadministration of dexamethasone (20 mg) for active SLE. Disease activity was assessed using the SLEDAI-2K score. Serum concentrations of anti-double-stranded DNA (anti-dsDNA) and vaccine-induced protective antibodies were monitored. Flow cytometry was performed to analyse peripheral blood B-cells, PCs and Siglec-1 expression on monocytes as surrogate marker for type-I interferon (IFN) activity. Upon proteasome inhibition, disease activity significantly declined and remained stable for 6 months on maintenance therapies. Nineteen treatment-emergent adverse events occurred and, although mostly mild to moderate, resulted in treatment discontinuation in seven patients. Serum antibody levels significantly declined, with greater reductions in anti-dsDNA (∼60%) than vaccine-induced protective antibody titres (∼30%). Bortezomib significantly reduced the numbers of peripheral blood and bone marrow PCs (∼50%), but their numbers increased between cycles. Siglec-1 expression on monocytes significantly declined. These findings identify proteasome inhibitors as a putative therapeutic option for patients with refractory SLE by targeting PCs and type-I IFN activity, but our results must be confirmed in controlled trials. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
    Annals of the Rheumatic Diseases 02/2015; 74(7). DOI:10.1136/annrheumdis-2014-206016 · 9.27 Impact Factor
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    ABSTRACT: To prospectively analyse the risk for disease relapses in patients with rheumatoid arthritis (RA) in sustained remission, either continuing, tapering or stopping disease-modifying antirheumatic drugs (DMARDs) in a prospective randomised controlled trial. Reduction of Therapy in patients with Rheumatoid arthritis in Ongoing remission is a multicentre, randomised controlled, parallel-group phase 3 trial evaluating the effects of tapering and stopping all conventional and/or biological DMARDs in patients with RA in stable remission. Patients (disease activity score 28 (DAS28)<2.6 for least 6 months) were randomised into three arms, either continuing DMARDs (arm 1), tapering DMARDs by 50% (arm 2) or stopping DMARDs after 6 months tapering (arm 3). The primary endpoint was sustained remission during 12 months. In this interim analysis, the first 101 patients who completed the study were analysed. At baseline, all patients fulfilled DAS28 remission and 70% also American College of Rheumatology- European League Against Rheumatism Boolean remission. 82.2% of the patients received methotrexate, 40.6% biological DMARDs and 9.9% other DMARDs. Overall, 67 patients (66.3%) remained in remission for 12 months, whereas 34 patients (33.7%) relapsed. The incidence of relapses was related to study arms (p=0.007; arm 1: 15.8%; arm 2: 38.9%; arm 3: 51.9%). Multivariate logistic regression identified anticitrullinated protein antibodies (ACPA) positivity (p=0.038) and treatment reduction (in comparison to continuation) as predictors for relapse (arm 2: p=0.012; arm 3: p=0.003). This randomised controlled study testing three different treatment strategies in patients with RA in sustained remission demonstrated that more than half of the patients maintain in remission after tapering or stopping conventional and biological DMARD treatment. Relapses occurred particularly in the first 6 months after treatment reduction and were associated with the presence of ACPA. 2009-015740-42. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
    Annals of the Rheumatic Diseases 02/2015; DOI:10.1136/annrheumdis-2014-206439 · 9.27 Impact Factor
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    ABSTRACT: Tribbles homologue 3 (TRB3) is a pseudokinase that modifies the activation of various intracellular signalling pathways to control fundamental processes extending from mitosis and cell activation to apoptosis and modulation of gene expression. Here, we aimed to analyse the role of TRB3 in fibroblast activation in systemic sclerosis (SSc). The expression of TRB3 was quantified by quantitative PCR, western blot and immunohistochemistry. The role of TRB3 was analysed in cultured fibroblasts and in experimental fibrosis using small interfering RNA (siRNA)-mediated knockdown and overexpression of TRB3. TRB3 expression was increased in fibroblasts of patients with SSc and in murine models of SSc in a transforming growth factor-β (TGF-β)/Smad-dependent manner. Overexpression of TRB3 stimulated canonical TGF-β signalling and induced an activated phenotype in resting fibroblasts. In contrast, knockdown of TRB3 reduced the profibrotic effects of TGF-β and decreased the collagen synthesis. Moreover, siRNA-mediated knockdown of TRB3 exerted potent antifibrotic effects and ameliorated bleomycin as well as constitutively active TGF-β receptor I-induced fibrosis with reduced dermal thickening, decreased hydroxyproline content and impaired myofibroblast differentiation. The present study characterises TRB3 as a novel profibrotic mediator in SSc. TGF-β induces TRB3, which in turn activates canonical TGF-β/Smad signalling and stimulates the release of collagen, thereby inducing a positive feedback loop that may contribute to aberrant TGF-β signalling in SSc. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
    Annals of the Rheumatic Diseases 01/2015; DOI:10.1136/annrheumdis-2014-206234 · 9.27 Impact Factor
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    ABSTRACT: To test medication adherence using the Compliance-Questionnaire-Rheumatology (CQR). Invitation letter and CQR were sent to 240 patients with rheumatoid arthritis. Followup CQR was sent 3 months later. Adherence was evaluated using CQR 80% cutoff scores. Seventy-eight patients who were being treated with disease-modifying antirheumatic drugs provided full information on the CQR at both points in time. Eleven patients (14.1%) were classified as adherent based on taking compliance (TC), with only 3 patients (3.8%) adherent in regard to correct dosing (CD) [followup: 13 (16.7%) and 3 (3.8%) for TC and CD, respectively]. Nonadherence was not related to disease activity or side effects. We demonstrated low adherence, suggesting differences between doctors' records and patients' practice of antirheumatic drug therapy.
    The Journal of Rheumatology 01/2015; 42(3). DOI:10.3899/jrheum.140982 · 3.17 Impact Factor

Publication Stats

13k Citations
3,166.86 Total Impact Points

Institutions

  • 2007–2015
    • Universitätsklinikum Erlangen
      Erlangen, Bavaria, Germany
    • Maastricht University
      Maestricht, Limburg, Netherlands
    • Universitätsklinikum Münster
      Muenster, North Rhine-Westphalia, Germany
  • 2006–2015
    • Friedrich-Alexander Universität Erlangen-Nürnberg
      • Nikolaus-Fiebiger-Center of Molecular Medicine (NFZ)
      Erlangen, Bavaria, Germany
  • 2013
    • University of Leeds
      • Leeds Institute of Rheumatic and Musculoskeletal Medicine
      Leeds, England, United Kingdom
  • 2004–2013
    • University of Innsbruck
      • Institute of Biochemistry
      Innsbruck, Tyrol, Austria
  • 2012
    • University of British Columbia - Vancouver
      • Department of Psychology
      Vancouver, British Columbia, Canada
    • University of Amsterdam
      • Faculty of Medicine AMC
      Amsterdamo, North Holland, Netherlands
    • Nordic Bioscience
      København, Capital Region, Denmark
  • 2011
    • National Academy of Sciences of Ukraine
      • Institute of Cell Biology
      Kharkiv, Kharkivs'ka Oblast', Ukraine
  • 2007–2011
    • University of Glasgow
      • • College of Medical, Veterinary and Life Sciences
      • • Institute of Infection, Immunity and Inflammation
      Glasgow, SCT, United Kingdom
  • 2008–2010
    • Nuremberg University of Music
      Nuremberg, Bavaria, Germany
  • 2009
    • University of Texas Southwestern Medical Center
      Dallas, Texas, United States
  • 1998–2008
    • Medical University of Vienna
      • Department of Medicine II
      Wien, Vienna, Austria
  • 2004–2006
    • Biomedical Sciences Research Center Alexander Fleming
      • Institute of Immunology
      Βάρη, Attica, Greece
  • 1998–2006
    • University of Vienna
      • Department of Internal Medicine III
      Wien, Vienna, Austria
  • 2005
    • University of Verona
      Verona, Veneto, Italy
  • 1995–2005
    • Austrian Academy of Sciences
      • • Forschungszentrum für Molekulare Medizin (CeMM)
      • • Institut für Biomedizinische Alternsforschung
      Mondsee, Upper Austria, Austria
  • 2000
    • Vienna General Hospital
      Wien, Vienna, Austria