A novel function of IL-2: chemokine/chemoattractant/retention receptor genes induction in Th subsets for skin and lung inflammation

IL-27 Gene Therapy Ameliorates IPEX Syndrome Caused by Germline Mutation of Foxp3 Gene: A Major Role for Induction of IL-10

Inactivating mutations of Foxp3, the master regulator of regulatory T cell development and function, lead to immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome in mice and humans. IPEX is a fatal autoimmune disease, with allogeneic stem cell transplant being the only available therapy. In this study, we report that a single dose of adeno-associated virus (AAV)-IL-27 to young mice with naturally occurring Foxp3 mutation (Scurfy mice) substantially ameliorates clinical symptoms, including growth retardation and early fatality. Correspondingly, AAV-IL-27 gene therapy significantly prevented naive T cell activation, as manifested by downregulation of CD62L and upregulation of CD44, and immunopathology typical of IPEX. Because IL-27 is known to induce IL-10, a key effector molecule of regulatory T cells, we evaluated the contribution of IL-10 induction by crossing IL-10-null allele to Scurfy mice. Although IL-10 deficiency does not affect the survival of Scurfy mice, it largely abrogated the therapeutic effect of AAV-IL-27. Our study revealed a major role for IL-10 in AAV-IL-27 gene therapy and demonstrated that IPEX is amenable to gene therapy.

Mutations from patients with IPEX ported to mice reveal different patterns of FoxP3 and Treg dysfunction

Mutations of the transcription factor FoxP3 in patients with "IPEX" (immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome) disrupt regulatory T cells (Treg), causing an array of multiorgan autoimmunity. To understand the functional impact of mutations across FoxP3 domains, without genetic and environmental confounders, six human FOXP3 missense mutations are engineered into mice. Two classes of mutations emerge from combined immunologic and genomic analyses. A mutation in the DNA-binding domain shows the same lymphoproliferation and multiorgan infiltration as complete FoxP3 knockouts but delayed by months. Tregs expressing this mutant FoxP3 are destabilized by normal Tregs in heterozygous females compared with hemizygous males. Mutations in other domains affect chromatin opening differently, involving different cofactors and provoking more specific autoimmune pathology (dermatitis, colitis, diabetes), unmasked by immunological challenges or incrossing NOD autoimmune-susceptibility alleles. This work establishes that IPEX disease heterogeneity results from the actual mutations, combined with genetic and environmental perturbations, explaining then the intra-familial variation in IPEX.

Amorphous Silica Nanoparticles Obtained by Laser Ablation Induce Inflammatory Response in Human Lung Fibroblasts

Silica nanoparticles (SiO₂ NPs) represent environmentally born nanomaterials that are used in multiple biomedical applications. Our aim was to study the amorphous SiO₂ NP-induced inflammatory response in MRC-5 human lung fibroblasts up to 72 hours of exposure. The intracellular distribution of SiO₂ NPs was measured by transmission electron microscopy (TEM). The lactate dehydrogenase (LDH) test was used for cellular viability evaluation. We have also investigated the lysosomes formation, protein expression of interleukins (IL-1β, IL-2, IL-6, IL-8, and IL-18), COX-2, Nrf2, TNF-α, and nitric oxide (NO) production. Our results showed that the level of lysosomes increased in time after exposure to the SiO₂ NPs. The expressions of interleukins and COX-2 were upregulated, whereas the expressions and activities of MMP-2 and MMP-9 decreased in a time-dependent manner. Our findings demonstrated that the exposure of MRC-5 cells to 62.5 µg/mL of SiO₂ NPs induced an inflammatory response.

Regulatory T cells in acute and chronic kidney diseases

Foxp3-expressing CD4+ regulatory T cells (Tregs) make up one subset of the helper T cells (Th) and are one of the major mechanisms of peripheral tolerance. Tregs prevent abnormal activation of the immune system throughout the lifespan, thus protecting from autoimmune and inflammatory diseases. Recent studies have elucidated the role of Tregs beyond autoimmunity. Tregs play important functions in controlling not only innate and adaptive immune cell activation, but also regulate nonimmune cell function during insults and injury. Inflammation contributes to a multitude of acute and chronic diseases affecting the kidneys. This review examines the role of Tregs in pathogenesis of renal inflammatory diseases and explores the approaches for enhancing Tregs for prevention and therapy of renal inflammation.

Systemic Activation of NRF2 Alleviates Lethal Autoimmune Inflammation in Scurfy Mice

The transcription factor NRF2 (nuclear factor [erythroid-derived 2]-like 2) plays crucial roles in the defense mechanisms against oxidative stress and mediates anti-inflammatory actions under various pathological conditions. Recent studies showed that the dysfunction of regulatory T cells (Tregs) is directly linked to the initiation and progression of various autoimmune diseases. To determine the Treg-independent impact of NRF2 activation on autoimmune inflammation, we examined scurfy (Sf) mice, which are deficient in Tregs and succumb to severe multiorgan inflammation by 4 weeks of age. We found that systemic activation of NRF2 by Keap1 (Kelch-like ECH-associated protein 1) knockdown ameliorated tissue inflammation and lethality in Sf mice. Activated T cells and their cytokine production were accordingly decreased by Keap1 knockdown. In contrast, NRF2 activation through cell lineage-specific Keap1 disruption (i.e., in T cells, myeloid cells, and dendritic cells) achieved only partial or no improvement in the inflammatory status of Sf mice. Our results indicate that systemic activation of NRF2 suppresses effector T cell activities independently of Tregs and that NRF2 activation in multiple cell lineages appears to be required for sufficient anti-inflammatory effects. This study emphasizes the possible therapeutic application of NRF2 inducers in autoimmune diseases that are accompanied by Treg dysfunction.

T cells and autoimmune kidney disease

Glomerulonephritis is traditionally considered to result from the invasion of the kidney by autoantibodies and immune complexes from the circulation or following their formation in situ, and by cells of the innate and the adaptive immune system. The inflammatory response leads to the proliferation and dysfunction of cells of the glomerulus, and invasion of the interstitial space with immune cells, resulting in tubular cell malfunction and fibrosis. T cells are critical drivers of autoimmunity and related organ damage, by supporting B-cell differentiation and antibody production or by directly promoting inflammation and cytotoxicity against kidney resident cells. T cells might become activated by autoantigens in the periphery and become polarized to secrete inflammatory cytokines before entering the kidney where they have the opportunity to expand owing to the presence of costimulatory molecules and activating cytokines. Alternatively, naive T cells could enter the kidney where they become activated after encountering autoantigen and expand locally. As not all individuals with a peripheral autoimmune response to kidney antigens develop glomerulonephritis, the contribution of local kidney factors expressed or produced by kidney cells is probably of crucial importance. Improved understanding of the biochemistry and molecular biology of T cells in patients with glomerulonephritis offers unique opportunities for the recognition of treatment targets for autoimmune kidney disease.

Affinity for self antigen selects Treg cells with distinct functional properties

The manner in which regulatory T cells (Treg cells) control lymphocyte homeostasis is not fully understood. We identified two Treg cell populations with differing degrees of self-reactivity and distinct regulatory functions. We found that GITR(hi)PD-1(hi)CD25(hi) (Triple(hi)) Treg cells were highly self-reactive and controlled lympho-proliferation in peripheral lymph nodes. GITR(lo)PD-1(lo)CD25(lo) (Triple(lo)) Treg cells were less self-reactive and limited the development of colitis by promoting the conversion of CD4(+) Tconv cells into induced Treg cells (iTreg cells). Although Foxp3-deficient (Scurfy) mice lacked Treg cells, they contained Triple(hi)-like and Triple(lo)-like CD4(+) T cells zsuper> T cells infiltrated the skin, whereas Scurfy Triple(lo)CD4(+) T cells induced colitis and wasting disease. These findings indicate that the affinity of the T cell antigen receptor for self antigen drives the differentiation of Treg cells into distinct subsets with non-overlapping regulatory activities.

Evaluation and treatment of critical asthma syndrome in children

The heterogeneity of asthma is illustrated by the significantly different features of pediatric asthma compared to adult asthma. One phenotype of severe asthma in pediatrics includes atopy, lack of reduction in lung function, and absence of gender bias as the main characteristics. Included in the NIH NAEPP EPR-3 are recommendations for the treatment and management of severe pediatric asthma and critical asthma syndrome, such as continuous nebulization treatments, intubation and mechanical ventilation, heliox, and magnesium sulfate. In addition, epinephrine, intravenous immunoglobulin, intravenous montelukast, extracorporeal membrane oxygenation, and many biological modulators currently under investigation are additional current and/or future treatment modalities for the severe pediatric asthmatic. But, perhaps the most important strategy for managing the severe asthmatic is preventative treatment, which can significantly decrease impairment and risk, particularly for severe acute exacerbations requiring emergency care and/or hospitalization. In order for preventative therapy to be successful, several challenges must be met, including selecting the correct therapy for each patient and then ensuring compliance or adherence to a treatment plan. The heterogeneity of asthma renders the former difficult in that not all patients will respond equally to the same treatment; the latter is only helpful if the correct treatment is employed. Strategies to ensure compliance include education of caregivers and patients and their families. As newer medications are introduced, options for individualized or customized medicine increase, and this may pave the way for significant decreases in morbidity and mortality in severe pediatric asthma.

PARP inhibition by olaparib or gene knockout blocks asthma-like manifestation in mice by modulating CD4(+) T cell function

Background

An important portion of asthmatics do not respond to current therapies. Thus, the need for new therapeutic drugs is urgent. We have demonstrated a critical role for PARP in experimental asthma. Olaparib, a PARP inhibitor, was recently introduced in clinical trials against cancer. The objective of the present study was to examine the efficacy of olaparib in blocking established allergic airway inflammation and hyperresponsiveness similar to those observed in human asthma in animal models of the disease.

Methods

We used ovalbumin (OVA)-based mouse models of asthma and primary CD4⁺ T cells. C57BL/6J WT or PARP-1^−/− mice were subjected to OVA sensitization followed by a single or multiple challenges to aerosolized OVA or left unchallenged. WT mice were administered, i.p., 1 mg/kg, 5 or 10 mg/kg of olaparib or saline 30 min after each OVA challenge.

Results

Administration of olaparib in mice 30 min post-challenge promoted a robust reduction in airway eosinophilia, mucus production and hyperresponsiveness even after repeated challenges with ovalbumin. The protective effects of olaparib were linked to a suppression of Th2 cytokines eotaxin, IL-4, IL-5, IL-6, IL-13, and M-CSF, and ovalbumin-specific IgE with an increase in the Th1 cytokine IFN-γ. These traits were associated with a decrease in splenic CD4⁺ T cells and concomitant increase in T-regulatory cells. The aforementioned traits conferred by olaparib administration were consistent with those observed in OVA-challenged PARP-1^−/− mice. Adoptive transfer of Th2-skewed OT-II-WT CD4⁺ T cells reversed the Th2 cytokines IL-4, IL-5, and IL-10, the chemokine GM-CSF, the Th1 cytokines IL-2 and IFN-γ, and ovalbumin-specific IgE production in ovalbumin-challenged PARP-1^−/−mice suggesting a role for PARP-1 in CD4⁺ T but not B cells. In ex vivo studies, PARP inhibition by olaparib or PARP-1 gene knockout markedly reduced CD3/CD28-stimulated gata-3 and il4 expression in Th2-skewed CD4⁺ T cells while causing a moderate elevation in t-bet and ifn-γ expression in Th1-skewed CD4⁺ T cells.

Conclusions

Our findings show the potential of PARP inhibition as a viable therapeutic strategy and olaparib as a likely candidate to be tested in human asthma clinical trials.

Less travelled roads in clinical immunology and allergy: drug reactions and the environmental influence

Allergy and clinical immunology are examples of areas of knowledge in which working hypotheses are dominant over mechanistic understanding. As such, sometimes scientific efforts follow major streams and overlook some epidemiologically prevalent conditions that thus become underestimated by the research community. For this reason, we welcome the present issue of Clinical Reviews in Allergy and Immunology that is dedicated to uncommon themes in clinical immunology and allergy. First, comprehensive discussions are provided for allergy phenomena of large potential impact in clinical practice such as reactions to cephalosporins or aspirin-induced asthma and in everyday life such as allergies to food additives or legumes. Further, the issue addresses other uncommon themes such as urticaria and angioedema, cercarial dermatitis, or late-onset inflammation to soft tissue fillers. Last, there will be discussion on transversal issues such as olfactory defects in autoimmunity, interleukin 1 beta pathway, and the search for new serological markers in chronic inflammation. As a result, we are convinced that this issue will be of help to clinicians involved in internal medicine as well as to allergists and clinical immunologists. More importantly, we are convinced that these discussions will be of interest also to basic scientists for the numerous translational implications.

Autoimmunity: from black water fever to regulatory function

Autoimmunity is a field that has only been around for a little over a century. Initially, it was thought that autoimmunity could not happen, that the body would never turn on itself (i.e. "horror autotoxicus"). It was only around the First World War that autoimmunity was recognized as the pathogenesis of various diseases, including rheumatoid arthritis. The discovery of Compound E led to successful treatment of patients with autoimmune diseases, but it was not till later that the adverse effects of this class of drugs were elucidated. The "modern" age of autoimmunity began around 1945 with the description of blackwater fever, and most of the subsequent research on hemolytic anemia and the role of an autoantibody in its pathogenesis led to a description of the anti-globulin reaction. The lupus erythematous (LE) cell was recognized in the mid-1940s by Hargreaves. His research carried on into the 1960s. Rheumatoid factor was also first described in the 1940s as yet another serum factor with activity against globulin-coated sheep red blood cells. The concept of autoimmunity really gained a foothold in the 1950s, when autoimmune thyroid disease and idiopathic thrombocytopenia were first described. Much has happened since then, and our understanding of autoimmunity has evolved now to include mechanisms of apoptosis, signaling pathway derangements, and the discovery of subsets of T cells with regulatory activity. The modern day study of autoimmunity is a fascinating area of research, and full understanding of the pathogenesis of autoimmune diseases is far from being completely elucidated.

Aberrant muscle antigen exposure in mice is sufficient to cause myositis in a Treg cell-deficient milieu

Objective

Myositis is associated with muscle-targeted inflammation and is observed in some Treg cell–deficient mouse models. Because an autoimmune pathogenesis has been strongly implicated, the aim of this study was to investigate the hypothesis that abnormal exposure to muscle antigens, as observed in muscle injury, can induce autoimmune-mediated myositis in susceptible hosts.

Methods

FoxP3 mutant (scurfy) mice were mated to synaptotagmin VII (Syt VII) mutant mice, which resulted in a new mouse strain that combines impaired membrane resealing with Treg cell deficiency. Lymphocyte preparations from double-mutant mice were adoptively transferred intraperitoneally, with or without purified Treg cells, into recombination-activating gene 1 (RAG-1)–null recipients. Lymph node cells from mice with the FoxP3 mutation were transferred into RAG-1–null mice either 1) intraperitoneally in conjunction with muscle homogenate or purified myosin protein or 2) intramuscularly with or without cotransfer of purified Treg cells.

Results

FoxP3-deficient mouse lymph node cells transferred in conjunction with myosin protein or muscle homogenate induced robust skeletal muscle inflammation. The infiltrates consisted predominantly of CD4+ and CD8+ T cells, a limited number of macrophages, and no B cells. Significant inflammation was also seen in similar experiments using lymph node cells from FoxP3/Syt VII double-mutant mice but was absent in experiments using adoptive transfer of FoxP3 mutant mouse cells alone. The cotransfer of Treg cells completely suppressed myositis.

Conclusion

These data, derived from a new, reproducible model, demonstrate the critical roles of Treg cell deficiency and aberrant muscle antigen exposure in the priming of autoreactive cells to induce myositis. This mouse system has multifaceted potential for examining the interplay in vivo between tissue injury and autoimmunity.

Hookworm-related cutaneous larva migrans in patients living in an endemic community in Brazil: immunological patterns before and after ivermectin treatmen

Hookworm-related cutaneous larva migrans (Hr-CLM) is caused by animal hookworm larvae migrating in the human epidermis where they elicit an inflammatory response. This study describes the immunological profile in Hr-CLM patients. In 77 Hr-CLM patients from Manaus, Brazil, peripheral eosinophils were counted, and serum concentrations of total immunoglobulin E (IgE) and selected cytokines were determined by ELISA before and after treatment with ivermectin. Controls included patients' household members (endemic controls), non-endemic Brazilian and Japanese individuals. Eosinophil counts and total IgE in Hr-CLM patients were higher than in controls and correlated with disease severity. Concentrations of interleukin (IL)-4, IL-5, IL-6, and IL-10 were higher in Hr-CLM patients than in endemic controls (p < 0.001) while no differences were detected for interferon (IFN)-γ, tumor necrosis factor (TNF)-α, IL-1β, IL-2, or transforming growth factor (TGF)-β. Following ivermectin treatment, numbers of eosinophils and concentrations of IL-4, IL-5, and IL-10 decreased whereas IgE, IFN-γ, and TGF-β concentrations increased. The IL-5/IFN-γ ratio declined from 5.9 (interquartile range [IQR] 0.8-31.6) before to 0.1 (IQR 0.05-0.2; p = 0.001) after treatment. Thus, although an impact of other infections on the immune parameters determined cannot be excluded, Hr-CLM in endemic areas is associated with eosinophilia and elevated cytokine levels, particularly of IL-5 and IL-10, which decrease following ivermectin treatment.

IL-2 controls trafficking receptor gene expression and Th2 response for skin and lung inflammation

Both Il2(-/-) mice and Scurfy (Sf) mutant mice that are deficient in FoxP3, develop multi-organ inflammation but only the latter display severe skin and lung inflammation. In contrast, Sf.Il2(-/-) double mutant mice do not display skin inflammation and markedly reduced lung inflammation. In this review, we summarize our recent findings based on microarray, q-PCR and functional studies of 10 Sf double mutant mice. These studies revealed novel pro-inflammatory functions of IL-2 in regulating inflammation in an organ-specific manner. IL-2 exerts its "organ-specific" pro-inflammatory function by regulating the migration and retention of CD4(+) T-cells (both Th1 and Th2) specifically to the skin and lung. In addition, IL-2 is also required for regulating the Th2 cytokine response during T-cell activation. Further studies on these IL-2-regulated genes will help in identifying novel targets for intervention in inflammatory diseases of skin and lung.

The dual roles of inflammatory cytokines and chemokines in the regulation of autoimmune diseases and their clinical implications

Cytokines and chemokines are secreted, small cell-signaling protein molecules, whose receptors are expressed on immune cells. These factors play a critical role in immune cell differentiation, migration, and polarization into functional subtypes and in directing their biological functions. Much attention has been devoted to exploring the role of key inflammatory cytokines and promigratory chemokines in autoimmune, autoinflammatory, and allergic diseases, leading to development of therapeutic strategies that are based on their targeted neutralization. Recent studies, including those coming from our groups, show that several major proinflammatory cytokines and chemokines, including IFN-γ, IL-2, CCL2, and CXCL12, may also function as anti-inflammatory mediators and therefore, may have potential as anti-inflammatory drugs. Likewise, major anti-inflammatory mediators, such as TGF-β, may under certain conditions, in combination with other cytokines, exhibit proinflammatory function and direct the polarization of the highly inflammatory CD4(+) Th17 cells. We show here that the biological function of pro- and anti-inflammatory cytokines is dependent on three key parameters: the local concentration of a given cytokine, the stage of disease in which it is administered, and its combination with other cytokines. The therapeutic implications of these findings are discussed, including two very recent studies summarizing clinical trials, in which low-dose administration of IL-2 was used to successfully suppress HCV and GVHD.

Loss of STAT6 promotes autoimmune disease and atopy on a susceptible genetic background

Atopy and autoimmunity are usually considered opposed immunological manifestations. Lyn(-/-) mice develop lupus-like autoimmune disease yet have coexistent intrinsic allergic traits and are prone to severe, persistent asthma induced exogenously. Recently it has been proposed that the Th2 environment and IgE auto-Abs promotes autoimmune disease in Lyn(-/-) mice. To examine this apparent contradiction, we derived Lyn(-/-) mice with a null mutation in STAT6, a regulator of Th2 immunity that integrates signaling from the IL-4/IL-13 receptor complex. Atopy and spontaneous peritoneal eosinophilia, characteristic of Lyn(-/-) mice, were lost in young Lyn(-/-)STAT6(-/-) mice; however, autoimmune disease was markedly exacerbated. At a time-point where Lyn(-/-) mice showed only mild autoimmune disease, Lyn(-/-)STAT6(-/-) mice had maximal titres of IgG and IgA auto-Abs, impaired renal function, myeloid expansion and a highly activated T cell compartment. Remarkably, low level IgE auto-Abs but not IgG1 auto-Abs were a feature of some aged Lyn(-/-)STAT6(-/-) mice. Furthermore, aged Lyn(-/-)STAT6(-/-) mice showed dramatically increased levels of serum IgE but minimal IgG1, suggesting that class-switching to IgE can occur in the absence of an IgG1 intermediate. The results show that Lyn-deficient mice can overcome the effects of disabling Th2 immunity, highlighting the importance of Lyn in controlling Th2 responses. Our data also indicates that, under certain conditions, STAT6-independent factors can promote IgE class-switching. This work has important clinical implications as many experimental therapies designed for the treatment of asthma or atopy are based on targeting the STAT6 axis, which could potentially reveal life endangering autoimmunity or promote atopy in susceptible individuals.

The Biology of Autoimmune Response in the Scurfy Mice that Lack the CD4+Foxp3+ Regulatory T-Cells

Due to a mutation in the Foxp3 transcription factor, Scurfy mice lack regulatory T-cells that maintain self-tolerance of the immune system. They develop multi-organ inflammation (MOI) and die around four weeks old. The affected organs are skin, tail, lungs and liver. In humans, endocrine and gastrointestinal inflammation are also observed, hence the disease is termed IPEX (Immunodysregulation, Polyendocrinopathy, Enteropathy, X-linked) syndrome. The three week period of fatal MOI offers a useful autoimmune model in which the controls by genetics, T-cell subsets, cytokines, and effector mechanisms could be efficiently investigated. In this report, we will review published work, summarize our recent studies of Scurfy double mutants lacking specific autoimmune-related genes, discuss the cellular and cytokine controls by these genes on MOI, the organ-specificities of the MOI controlled by environments, and the effector mechanisms regulated by specific Th cytokines, including several newly identified control mechanisms for organ-specific autoimmune response.