Abstract
Autoreactive T cells are a central element in many systemic autoimmune diseases. The generation of these pathogenic T cells is instructed by antigen presenting cells. However, signalling pathways in APC that drive autoimmunity are not completely understood. Here we show that that conditional deletion of PTEN in myeloid cells are almost completely protected from the development of two prototypic model autoimmune diseases, collagen induced arthritis (CIA) and experimental autoimmune encephalomyelitis (EAE). Myeloid specific deletion of PTEN lead to a significant reduction of cytokines pivotal for the induction of systemic autoimmunity such as IL-23 and IL-6 in vitro and in vivo. In addition, PTEN deficient dendritic cells showed reduced activation of p38 MAP-kinase and increased inhibitory phosphorylation of GSK3β in vitro. Dendritic cell and macrophage phenotypic maturation and migration to lymph nodes as well as collagen specific T and B cell activation was comparable in wt and myeloid specific PTEN-/-. However, analysing the impact of myeloid specific PTEN deficiency on T cell polarization, we found a significant reduction of a Th17 type of immune response characterized by reduced production of IL-17 and IL-22. Moreover, there was an increase in IL-4 production and higher numbers of regulatory T cells myeloid specific PTEN-/-. In contrast, myeloid specific PTEN deficiency did not affect serum transfer arthritis, which is independent of the adaptive immune system and solely depends on innate effector functions. These data demonstrate that the presence of PTEN in myeloid cells is required for the development of systemic autoimmunity. Deletion of PTEN in myeloid cells inhibits the development of CIA and EAE by preventing the generation of a pathogenic Th17 type of immune response.
Highlights
Acute isolated neurological syndromes, such as optic neuropathy or transverse myelopathy, may cause diagnostic problems since they can be the first presentations in a number of demyelinating disorders including multiple sclerosis (MS) and collagen diseases
tumor necrosis factor (TNF) therapy and demyelinating event: A report indicates that adverse events such as the demyelinating lesion in the brain, optic neuritis, and neuropathy occurred after treatment with anti-TNF alpha therapy in collagen disease, and TNF antagonizing therapy showed worsening in a clinical trial with MS
Believing on the similarities of normal joints in humans and monkeys, we have employed a model of collagen-induced arthritis in Macaca fascicularis in an attempt to evaluate the histological alterations caused by such condition in the extracellular matrix of the articular cartilage
Summary
Acute isolated neurological syndromes, such as optic neuropathy or transverse myelopathy, may cause diagnostic problems since they can be the first presentations in a number of demyelinating disorders including multiple sclerosis (MS) and collagen diseases. Acute Serum Amyloid A (A-SAA) is an acute phase protein strongly expressed in rheumatoid arthritis (RA) synovial tissue (ST) critically involved in regulating cell migration and angiogenesis These processes are dependent on downstream interactions between extracellular matrix and cytoskeletal components. Conclusions: These results indicate that Egr-1 contributes to IL-1mediated down-regulation of PPARg expression in OA chondrocytes and suggest that this pathway could be a potential target for pharmacologic intervention in the treatment of OA and possibly other arthritic diseases. Immune cell-derived microparticles (MPs) are present at increased amounts in synovial fluid of rheumatoid arthritis (RA) patients [1] and can activate disease-relevant signalling pathways in RA synovial fibroblasts (SF) [2,3].
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