Experimental Rheumatology

Nijmegen, Netherlands

Experimental Rheumatology

Nijmegen, Netherlands

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De Kleer I.,University Utrecht | Vercoulen Y.,University Utrecht | Klein M.,University Utrecht | Meerding J.,University Utrecht | And 6 more authors.
Journal of Immunology | Year: 2010

In many animal models, the manifestations of inflammatory diseases can be prevented by the adoptive transfer of CD4+FOXP3+ regulatory T cells (Tregs). CD4+FOXP3+ Tregs can be obtained by isolation and expansion of polyclonal naturally occurring Tregs or by Ag-specific activation of CD4+CD25-FOXP3- T cells. Two major obstacles are hampering the translation of this latter protocol into therapeutic application. First, there is a lack of knowledge on relevant autoantigens. Second, the resulting population is contaminated with activated CD4+ T cells that transiently express Forkhead box P3 but gain no regulatory function. Therefore, these cells may not be safe for clinical application. In this study, we demonstrate that highly suppressive FOXP3 + Tregs can be induced in vitro by the activation of CD4 +CD25- T cells with the self-Ag human 60-kDa heat shock protein (HSP60). The activation induced suppressive FOXP3+ Tregs can be distinguished by surface expression of CD30 from nonsuppressive FOXP3 + effector cells. We confirm that the induced CD30 +FOXP3+ Tregs recognize HSP60 epitopes and that the induction of Tregs by HSP60 is enhanced by signaling via TLR4 on APCs. These findings have implications for the generation and isolation of pure populations of Ag-specific Tregs, with the potential to prevent and treat human inflammatory diseases. Copyright © 2010 by The American Association of Immunologists, Inc.


Madej W.,Orthopaedic Research Laboratory | van Caam A.,Experimental Rheumatology | Blaney Davidson E.N.,Experimental Rheumatology | Hannink G.,Orthopaedic Research Laboratory | And 2 more authors.
Osteoarthritis and Cartilage | Year: 2016

Objective: Mechanical signals control key cellular processes in articular cartilage. Previously we have shown that mechanical compression is an important ALK5/Smad2/3P activator in cartilage explants. However, age-related changes in the cartilage are known to affect tissue mechanosensitivity and also ALK5/Smad2/3P signaling. We have investigated whether ageing of cartilage is associated with an altered response to mechanical compression. Design: Articular cartilage explants of two different age groups (young-6-36 months old, aged-6 - 13 years old) were subjected to dynamic mechanical compression with 3 MPa (physiological) or 12 MPa (excessive) load. Subsequently, essential cartilage extracellular matrix (ECM) components and tissue growth factors gene expression was measured in young and aged cartilage by QPCR. Furthermore, the ability of young and aged cartilage, to activate the Smad2/3P signaling in response to compression was analyzed and compared. This was done by immunohistochemical (IH) Smad2P detection and Smad3-responsive gene expression analysis. Results: Aged cartilage showed a highly reduced capacity for mechanically-mediated activation of Smad2/3P signaling when compared to young cartilage. Compression of aged cartilage, induced collagen type II (Col2a1) and fibronectin (Fn1) expression to a far lesser extent than in young cartilage. Additionally, in aged cartilage no mechanically mediated up-regulation of bone morphogenetic protein 2 (Bmp2) and connective tissue growth factor (Ctgf) was observed. Conclusions: We identified age-related changes in cellular responses to mechanical stimulation of articular cartilage. We propose that these changes might be associated with age-related alterations in cartilage functioning and can underlie mechanisms for development of age-related cartilage diseases like osteoarthritis (OA). © 2015 Osteoarthritis Research Society International.


PubMed | Orthopaedic Research Laboratory and Experimental Rheumatology
Type: Journal Article | Journal: Osteoarthritis and cartilage | Year: 2015

Mechanical signals control key cellular processes in articular cartilage. Previously we have shown that mechanical compression is an important ALK5/Smad2/3P activator in cartilage explants. However, age-related changes in the cartilage are known to affect tissue mechanosensitivity and also ALK5/Smad2/3P signaling. We have investigated whether ageing of cartilage is associated with an altered response to mechanical compression.Articular cartilage explants of two different age groups (young-6-36 months old, aged-6 - 13 years old) were subjected to dynamic mechanical compression with 3 MPa (physiological) or 12 MPa (excessive) load. Subsequently, essential cartilage extracellular matrix (ECM) components and tissue growth factors gene expression was measured in young and aged cartilage by QPCR. Furthermore, the ability of young and aged cartilage, to activate the Smad2/3P signaling in response to compression was analyzed and compared. This was done by immunohistochemical (IH) Smad2P detection and Smad3-responsive gene expression analysis.Aged cartilage showed a highly reduced capacity for mechanically-mediated activation of Smad2/3P signaling when compared to young cartilage. Compression of aged cartilage, induced collagen type II (Col2a1) and fibronectin (Fn1) expression to a far lesser extent than in young cartilage. Additionally, in aged cartilage no mechanically mediated up-regulation of bone morphogenetic protein 2 (Bmp2) and connective tissue growth factor (Ctgf) was observed.We identified age-related changes in cellular responses to mechanical stimulation of articular cartilage. We propose that these changes might be associated with age-related alterations in cartilage functioning and can underlie mechanisms for development of age-related cartilage diseases like osteoarthritis (OA).


Madej W.,Orthopedic Research Laboratory | van Caam A.,Experimental Rheumatology | Blaney Davidson E.,Experimental Rheumatology | Buma P.,Orthopedic Research Laboratory | van der Kraan P.M.,Experimental Rheumatology
Osteoarthritis and Cartilage | Year: 2016

Objective Recently it was shown that loading of articular cartilage explants activates TGFβ signaling. Here we investigated if in vivo chondrocytes express permanently high TGFβ signaling, and the consequence of the loss of compressive loading-mediated TGFβ signaling on chondrocyte function and phenotype. Method Bovine articular cartilage explants were collected within 10 min post mortem and stained immediately and after 30, 60 and 360 min for phosphorylated-Smad2, indicating active TGFβ signaling. Explants were unloaded for 48 h and subsequently repeatedly loaded with a compressive load of 3 MPa. In addition, explants were cultured unloaded for 2 weeks and the effect of loading or exogenous TGFβ on proteoglycan level and chondrocyte phenotype (Col10a1 mRNA expression) was analyzed. Results Unloading of articular cartilage results in rapid loss of TGFβ signaling while subsequent compressive loading swiftly restored this. Loading and exogenous TGFβ enhanced expression of TGFβ1 and ALK5. Unloading of explants for 2 weeks resulted in proteoglycan loss and increased Col10a1 expression. Both loading and exogenous TGFβ inhibited elevated Col10a1 expression but not proteoglycan loss. Conclusion Our data might imply that in vivo regular physiological loading of articular cartilage leads to enduring TGFβ signaling and TGFβ-induced gene expression. We propose a hypothetical model in which loading activates a self-perpetuating system that prevents hypertrophic differentiation of chondrocytes and is crucial for cartilage homeostasis. © 2016 Osteoarthritis Research Society International


PubMed | Orthopedic Research Laboratory and Experimental Rheumatology
Type: Journal Article | Journal: Osteoarthritis and cartilage | Year: 2016

Recently it was shown that loading of articular cartilage explants activates TGF signaling. Here we investigated if invivo chondrocytes express permanently high TGF signaling, and the consequence of the loss of compressive loading-mediated TGF signaling on chondrocyte function and phenotype.Bovine articular cartilage explants were collected within 10min post mortem and stained immediately and after 30, 60 and 360min for phosphorylated-Smad2, indicating active TGF signaling. Explants were unloaded for 48h and subsequently repeatedly loaded with a compressive load of 3MPa. In addition, explants were cultured unloaded for 2 weeks and the effect of loading or exogenous TGF on proteoglycan level and chondrocyte phenotype (Col10a1 mRNA expression) was analyzed.Unloading of articular cartilage results in rapid loss of TGF signaling while subsequent compressive loading swiftly restored this. Loading and exogenous TGF enhanced expression of TGF1 and ALK5. Unloading of explants for 2 weeks resulted in proteoglycan loss and increased Col10a1 expression. Both loading and exogenous TGF inhibited elevated Col10a1 expression but not proteoglycan loss.Our data might imply that invivo regular physiological loading of articular cartilage leads to enduring TGF signaling and TGF-induced gene expression. We propose a hypothetical model in which loading activates a self-perpetuating system that prevents hypertrophic differentiation of chondrocytes and is crucial for cartilage homeostasis.


PubMed | Experimental Rheumatology., Radboud University Nijmegen and Experimental Rheumatology
Type: | Journal: Rheumatology (Oxford, England) | Year: 2016

A crucial feature of OA is cartilage degradation. This process is mediated by pro-inflammatory cytokines, among other factors, via induction of matrix-degrading enzymes. Interleukin 37 (IL37) is an anti-inflammatory cytokine and is efficient in blocking the production of pro-inflammatory cytokines during innate immune responses. We hypothesize that IL37 is therapeutic in treating the inflammatory cytokine cascade in human OA chondrocytes and can act as a counter-regulatory cytokine to reduce cartilage degradation in OA.Human OA cartilage was obtained from patients undergoing total knee or hip arthroplasty. Immunohistochemistry was applied to study IL37 protein expression in cartilage biopsies from OA patients. Induction of IL37 expression by IL1, OA synovium-conditioned medium and TNF was investigated in human OA chondrocytes. Adenoviral overexpression of IL37 followed by IL1 stimulation was performed to investigate the anti-inflammatory potential of IL37.IL37 expression was detected in cartilage biopsies of OA patients and induced by IL1. After IL1 stimulation, increased IL1, IL6 and IL8 expression was observed in OA chondrocytes. Elevated IL37 levels diminished the IL1-induced IL1, IL6 and IL8 gene levels and IL1 and IL8 protein levels. In addition to the reduction in pro-inflammatory cytokine expression, IL37 reduced MMP1, MMP3, MMP13 and disintegrin and metalloproteinase with thrombospondin motifs 5 gene levels and MMP3 and MMP13 protein levels.IL37 is induced by IL1, and IL37 itself reduced IL1, IL6 and IL8 production, indicating that IL37 is able to induce a counter-regulatory anti-inflammatory feedback loop in chondrocytes. In addition, IL37 dampens catabolic enzyme expression. This supports IL37 as a potential therapeutic target in OA.


PubMed | Experimental Rheumatology
Type: | Journal: Arthritis research & therapy | Year: 2015

Pro-inflammatory cytokines and bone morphogenetic proteins are generally studied separately and considered to be elements of different worlds, immunology and developmental biology. Varas and colleagues report that these factors show cross-talk in rheumatoid arthritis synoviocytes. They show that pro-inflammatory cytokines not only stimulate the production of bone morphogenetic proteins but that these endogenously produced bone morphogenetic proteins interfere with the effects of pro-inflammatory cytokines on synoviocytes.

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