APL1, an altered peptide ligand derived from human heat-shock protein 60, increases the frequency of Tregs and its suppressive capacity against antigen responding effector CD4 + T cells from rheumatoid arthritis patients.

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by a chronic relapsing-remitting joint inflammation. Perturbations in the balance between CD4 + T cells producing IL-17 and CD4 + CD25(high)FoxP3 + Tregs correlate with irreversible bone and cartilage destruction in RA. APL1 is an altered peptide ligand derived from a CD4+ T-cell epitope of human HSP60, an autoantigen expressed in the inflamed synovium, which increases the frequency of CD4 + CD25(high)FoxP3+ Tregs in peripheral blood mononuclear cells from RA patients. The aim of this study was to evaluate the suppressive capacity of Tregs induced by APL1 on proliferation of effector CD4+ T cells using co-culture experiments. Enhanced Treg-mediated suppression was observed in APL1-treated cultures compared with cells cultured only with media. Subsequent analyses using autologous cross-over experiments showed that the enhanced Treg suppression in APL1-treated cultures could reflect increased suppressive function of Tregs against APL1-responsive T cells. On the other hand, APL1-treatment had a significant effect reducing IL-17 levels produced by effector CD4+ T cells. Hence, this peptide has the ability to increase the frequency of Tregs and their suppressive properties whereas effector T cells produce less IL-17. Thus, we propose that APL1 therapy could help to ameliorate the pathogenic Th17/Treg balance in RA patients.

APL-2, an altered peptide ligand derived from heat-shock protein 60, induces interleukin-10 in peripheral blood mononuclear cell derived from juvenile idiopathic arthritis patients and downregulates the inflammatory response in collagen-induced arthritis model.

Juvenile idiopathic arthritis (JIA) is a heterogeneous group of diseases characterized by autoimmune arthritis of unknown cause with onset before age of 16 years. Methotrexate provides clinical benefits in JIA. For children who do not respond to methotrexate, treatment with anti-tumor necrosis factor (TNF)-α is an option. However, some patients do not respond or are intolerant to anti-TNF therapy. Induction of peripheral tolerance has long been considered a promising approach to the treatment of chronic autoimmune diseases. We aimed to evaluate the potentialities of two altered peptide ligands (APLs) derived from human heat-shock protein 60, an autoantigen involved in the pathogenesis of autoimmune arthritis, in JIA patients. Interferon (IFN)-γ, TNF-α and interleukin (IL)-10 levels were determined in ex vivo assays using peripheral blood mononuclear cells (PBMC) from these patients. Wild-type peptide and one of these APLs increased IFN-γ and TNF-α levels. Unlike, the other APLs (called APL2) increased the IL-10 level without affecting IFN-γ and TNF-α levels. On the other hand, APL2 induces a marked activation of T cells since it transforms cell cycle phase's distribution of CD4+ T cells from these patients. In addition, we evaluated the therapeutic effect of APL2 in collagen-induced arthritis model. Therapy with APL2 reduced arthritis scores and histological lesions in mice. This effect was associated to a decrease in TNF-α and IL-17 levels. These results indicate a therapeutic potentiality of APL2 for JIA.

APL-1, an altered peptide ligand derived from human heat-shock protein 60, selectively induces apoptosis in activated CD4+ CD25+ T cells from peripheral blood of rheumatoid arthritis patients.

Rheumatoid arthritis (RA) is a chronic T-cell mediated autoimmune disease that affects primarily the joints. The induction of immune tolerance through antigen-specific therapies for the blockade of pathogenic CD4+ T cells constitutes a current focus of research. In this focus it is attempted to simultaneously activate multiple regulatory mechanisms, such as: apoptosis and regulatory T cells (Tregs). APL-1 is an altered peptide ligand derived from a novel CD4+ T-cell epitope of human heat-shock protein of 60kDa, an autoantigen involved in the pathogenesis of RA. Previously, we have reported that APL-1 induces CD4+ CD25(high)Foxp3+ Tregs in several systems. Here, we investigated the ability of APL-1 in inducing apoptosis in PBMCs from RA patients, who were classified as active or inactive according to their DAS28 score. APL-1 decreased the viability of PBMCs from active but not from inactive patients. DNA fragmentation assays and typical morphological features clearly demonstrated that APL-1 induced apoptosis in these cells. Activated CD4+ CD25+ T cells but not resting CD4+ CD25- T cells were identified as targets of APL-1. Furthermore, CD4+ T-cell responses to APL-1 were found to be dependent on antigen presentation via the HLA-DR molecule. Thus, APL-1 is a regulatory CD4+ T cell epitope which might modulate inflammatory immune responses in PBMCs from RA patients by inducing CD4+ CD25(high)Foxp3+ Tregs and apoptosis in activated CD4+ T cells. These results support further investigation of this candidate drug for the treatment of RA.

Ozone oxidative postconditioning ameliorates joint damage and decreases pro-inflammatory cytokine levels and oxidative stress in PG/PS-induced arthritis in rats.

Rheumatoid Arthritis (RA) is the most prevalent chronic condition present in ~1% of the adult population. Many pro-inflammatory mediators are increased in RA, including Reactive Oxygen Species such as nitric oxide NO, pro-inflammatory cytokines as tumor necrosis factor alpha (TNF-α), interleukin-1beta (IL-1ß) and other molecules. Ozone oxidative postconditioning has regulatory effects on some pathological targets associated with RA. Thus, the aim of this study was to investigate the efficacy of ozone therapy in PG/PS-induced arthritis in rats in point of joints inflammation and morphology. Moreover, cytokines, nitric oxide and oxidative stress levels in spleen homogenates were evaluated. Ozone treatment ameliorated joint damage, reduced TNF-α concentrations as well as TNF-α and IL-1ß mRNA levels. Besides, cellular redox balance, nitric oxide and fructolysine levels were reestablished after ozone oxidative postconditioning. It was concluded that pleiotropic ozone's effects clarify its therapeutic efficacy in RA. Decreasing inflammation and joint injury, reduction of pro-inflammatory cytokines, TNF-α and IL-1ß transcripts and re-establishment of cellular redox balance after ozone treatment were demonstrated.

An altered peptide ligand corresponding to a novel epitope from heat-shock protein 60 induces regulatory T cells and suppresses pathogenic response in an animal model of adjuvant-induced arthritis.

Induction of immune tolerance as therapeutic approach for autoimmune diseases constitutes a current research focal point. In this sense, we aimed to evaluate an altered peptide ligand (APL) for induction of peripheral tolerance in patients with rheumatoid arthritis (RA). A novel T-cell epitope from human heat-shock protein 60 (Hsp60), an autoantigen involved in the pathogenesis of RA, was identified by bioinformatics tools and an APL was design starting from this epitope. We investigated the ability of this APL for inducing regulatory T cells (Treg cells) in mice and evaluated the therapeutic effect of this peptide in an adjuvant-induced arthritis (AA) rat model. Clinical score, TNFα levels and histopathology were monitored, as well as the capacity of this APL for inducing Treg cells. Finally, the potentialities of the APL for inducing Treg cells were evaluated in ex vivo assays using mononuclear cells isolated from peripheral blood (PBMC). The APL induced an increase of the proportions of Treg cells in the draining lymph nodes of the injected site in mice. The APL efficiently inhibited the course of AA, with significant reduction of the clinical and histopathology score. This effect was associated with an increase of the proportions of Treg cells and a decrease of TNFα levels in spleen. Finally, stimulation of PBMCs from RA patients by the APL increases the proportions of the CD4(+)CD25(high)FoxP3(+) Treg cells. These results indicate a therapeutic potentiality of APL and support further investigation of this candidate drug for treatment of RA.