A dual role for TNF-alpha in type 1 diabetes: islet-specific expression abrogates the ongoing autoimmune process when induced late but not early during pathogenesis

Evaluation of miRNA-146a, miRNA-34a, and pro-inflammatory cytokines as a potential early indicators for type 1 diabetes mellitus

Background

Type I diabetes mellitus (T1DM) is one of the most common chronic autoimmune diseases worldwide. miRNAs are a class of small non-coding RNA molecules that have been linked to immune system functions, β-cell metabolism, proliferation, and death, all of which contribute to pathogenesis of TIDM. Dysregulated miRNAs have been identified in Egyptian TIDM patients.

Aim

Several miRNAs were profiled in Egyptian TIDM patients to determine whether they can be used as molecular biomarkers for T1DM. The relationship between the investigated miRNAs and pro-inflammatory cytokines (TNF-α and IL-6) has also been evaluated in the development of TIDM, in addition to the creation of a proposed model for TIDM prediction.

Patients & methods

Case-control study included 177 Egyptian patients with confirmed type I diabetes mellitus and 177 healthy individuals. MiRNA-34 and miRNA-146 were detected in serum samples using real-time PCR, whereas TNF-α and IL-6 levels were assessed using ELIZA.

Results

Patients with TIDM showed a significant decrease in the expression of miRNA-146, with a cut-off value ≤ 3.3, 48 % specificity, and 92.1 % sensitivity, whereas miRNA-34 had the highest sensitivity (95.5 %) and specificity (97.2 %) for differentiating diabetic patients from controls. Furthermore, other diagnostic proinflammatory markers showed lower sensitivity and specificity.

Conclusion

Serum levels of miRNA-34a, miRNA-146, IL-6, and TNF-α provide new insights into T1DM pathogenesis and could be used for screening and diagnosis purposes. They can be also a potential therapeutic target, as well as allowing for more strategies to improve T1DM disease outcomes.

The Relationship between Type 1 Diabetes Mellitus, TNF-α, and IL-10 Gene Expression

Type 1 diabetes mellitus (T1DM) is one of the major chronic diseases in children worldwide. This study aimed to investigate interleukin-10 (IL-10) gene expression and tumor necrosis factor-alpha (TNF-α) in T1DM. A total of 107 patients were included, 15 were T1DM in ketoacidosis, 30 patients had T1DM and HbA1c ≥ 8%; 32 patients had T1DM and presented HbA1c < 8%; and 30 were controls. The expression of peripheral blood mononuclear cells was performed using the reverse transcriptase-polymerase chain reaction in real time. The cytokines gene expression was higher in patients with T1DM. The IL-10 gene expression increased substantially in patients with ketoacidosis, and there was a positive correlation with HbA1c. A negative correlation was found for IL-10 expression and the age of patients with diabetes, and the time of diagnosis of the disease. There was a positive correlation between TNF-α expression with age. The expression of IL-10 and TNF-α genes showed a significant increase in DM1 patients. Once current T1DM treatment is based on exogenous insulin, there is a need for other therapies, and inflammatory biomarkers could bring new possibilities to the therapeutic approach of the patients.

Effect of Epstein-Barr Virus Infection on Selected Immunological Parameters in Children with Type 1 Diabetes

Diabetes mellitus is a group of metabolic disorders with different etiologies, pathogeneses and clinical pictures, characterized by chronic hyperglycemia due to abnormal insulin secretion or action. Type 1 diabetes mellitus is the most common type of diabetes mellitus in children and adolescents, accounting for about 90% of diabetes in the population under the age of 18. The etiopathogenesis of type 1 diabetes is multifactorial. The disease occurs as a result of the interaction of three factors: genetic predisposition, environmental factors and the immune response. Research in recent years has focused on the involvement of Epstein-Barr virus (EBV) in the pathogenesis of type I diabetes. The goals of treating type 1 diabetes include maintaining blood-glucose, fructosamine and glycated hemoglobin (HbA1c) levels; therefore, the main purpose of this study was to evaluate the effect of EBV infection on the activation of selected immune cells, fructosamine levels and HbA1c levels in children with type I diabetes. Based on our study, we found a lower percentage of CD8+ T lymphocytes with expression of the CD69 molecule in patients with anti-VCA antibodies in the IgG class, and a lower percentage of CD8+ T lymphocytes with expression of the CD25+ molecule in patients with anti-EBNA-1 antibodies in the IgG class, which may indicate limited control of the immune system during EBV infection in patients. There was a lower percentage of CD3+CD4+ T lymphocytes secreting IL-4 in the study group, indicating that a deficiency in IL-4 production may be related to the development of type 1 diabetes. There was an increase in the percentage of CD4+CD3+IL-10 lymphocytes in the study group with anti-VCA antibodies present in the IgG class and anti-EBNA-1 antibodies in the IgG class compared to the patients without antibodies. In addition, there was a significant increase in fructosamine levels and higher glycated hemoglobin levels in the study group with antibodies to EBV antigens. In addition, an increase in the percentage of T lymphocytes with a CD4+CD3+IL-17+ phenotype in the patients with anti-VCA IgG antibodies was confirmed, and higher HbA1c levels may suggest that EBV infection is accompanied by an increase in IL-17 secretion.

The dichotomous outcomes of TNFα signaling in CD4+ T cells

TNFa blocking agents were the first-in-class biologic drugs used for the treatment of autoimmune disease. Paradoxically, however, exacerbation of autoimmunity was observed in some patients. TNFa is a pleiotropic cytokine that has both proinflammatory and regulatory effects on CD4+ T cells and can influence the adaptive immune response against autoantigens. Here, we critically appraise the literature and discuss the intricacies of TNFa signaling that may explain the controversial findings of previous studies. The pleiotropism of TNFa is based in part on the existence of two biologically active forms of TNFa, soluble and membrane-bound, with different affinities for two distinct TNF receptors, TNFR1 and TNFR2, leading to activation of diverse downstream molecular pathways involved in cell fate decisions and immune function. Distinct membrane expression patterns of TNF receptors by CD4+ T cell subsets and their preferential binding of distinct forms of TNFα produced by a diverse pool of cellular sources during different stages of an immune response are important determinants of the differential outcomes of TNFa-TNF receptor signaling. Targeted manipulation of TNFa-TNF receptor signaling on select CD4+ T cell subsets may offer specific therapeutic interventions to dampen inflammation while fortifying immune regulation for the treatment of autoimmune diseases.

Exocrine pancreas regeneration modifies original pancreas to alleviate diabetes in mouse models

Diabetes is a major public health issue because of its widely epidemic nature and lack of cure. Here, we show that pancreas-derived mesenchymal stem cells (PMSCs) are capable of regenerating exocrine pancreas when implanted into the kidney capsule of mice with streptozotocin (STZ)-induced diabetes. Mechanistically, we found that the regenerated exocrine pancreas elevated interleukin-6 (IL-6) in PMSC implants, which transiently activated tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) to inhibit IL-17, thereby rescuing damaged exocrine pancreas and islet β cells. In addition, we used knockout mouse models to show that global lack of IL-6, TNF-α, or IFN-γ resulted in increased severity of STZ-induced diabetes and resistance to PMSC implantation therapy, confirming the roles of these factors in safeguarding pancreatic β cells. Furthermore, removal of the kidney capsule PMSC implants at 28 days after implantation did not affect the PMSC-initiated therapeutic effect on diabetic mice. This study reveals a previously unknown role of exocrine pancreas regeneration in safeguarding β cells and demonstrates a "soil-rescues-seed" strategy for type 1 diabetes therapy.

Single-cell multi-omics analysis of human pancreatic islets reveals novel cellular states in type 1 diabetes

Type 1 diabetes (T1D) is an autoimmune disease in which immune cells destroy insulin-producing beta cells. The aetiology of this complex disease is dependent on the interplay of multiple heterogeneous cell types in the pancreatic environment. Here, we provide a single-cell atlas of pancreatic islets of 24 T1D, autoantibody-positive and nondiabetic organ donors across multiple quantitative modalities including ~80,000 cells using single-cell transcriptomics, ~7,000,000 cells using cytometry by time of flight and ~1,000,000 cells using in situ imaging mass cytometry. We develop an advanced integrative analytical strategy to assess pancreatic islets and identify canonical cell types. We show that a subset of exocrine ductal cells acquires a signature of tolerogenic dendritic cells in an apparent attempt at immune suppression in T1D donors. Our multimodal analyses delineate cell types and processes that may contribute to T1D immunopathogenesis and provide an integrative procedure for exploration and discovery of human pancreatic function.

Causal effects of inflammatory protein biomarkers on inflammatory diseases

Many circulating proteins are associated with the presence or severity of disease. However, whether these protein biomarkers are causal for disease development is usually unknown. We investigated the causal effect of 21 well-known or exploratory protein biomarkers of inflammation on 18 inflammatory diseases using two-sample Mendelian randomization. We identified six proteins to have causal effects on any of 11 inflammatory diseases (FDR < 0.05, corresponding to P < 1.4 × 10^–3). IL-12B protects against psoriasis and psoriatic arthropathy, LAP-TGF-β-1 protects against osteoarthritis, TWEAK protects against asthma, VEGF-A protects against ulcerative colitis, and LT-α protects against both type 1 diabetes and rheumatoid arthritis. In contrast, IL-18R1 increases the risk of developing allergy, hay fever, and eczema. Most proteins showed protective effects against development of disease rather than increasing disease risk, which indicates that many disease-related biomarkers are expressed to protect from tissue damage. These proteins represent potential intervention points for disease prevention and treatment.

Gold Nanoparticles: Multifaceted Roles in the Management of Autoimmune Disorders

Gold nanoparticles (GNPs) have been recently applied for various diagnostic and therapeutic purposes. The unique properties of these nanoparticles (NPs), such as relative ease of synthesis in various sizes, shapes and charges, stability, high drug-loading capacity and relative availability for modification accompanied by non-cytotoxicity and biocompatibility, make them an ideal field of research in bio-nanotechnology. Moreover, their potential to alleviate various inflammatory factors, nitrite species, and reactive oxygen production and the capacity to deliver therapeutic agents has attracted attention for further studies in inflammatory and autoimmune disorders. Furthermore, the characteristics of GNPs and surface modification can modulate their toxicity, biodistribution, biocompatibility, and effects. This review discusses in vitro and in vivo effects of GNPs and their functionalized forms in managing various autoimmune disorders (Ads) such as rheumatoid arthritis, type 1 diabetes, and multiple sclerosis.

MiR-126, IL-7, CXCR1/2 receptors, inflammation and circulating endothelial progenitor cells: The study on targets for treatment pathways in a model of subclinical cardiovascular disease (type 1 diabetes mellitus)

Background

Type 1 diabetes (T1DM) is associated with premature cardiovascular disease (CVD) and a pro-inflammatory state whilst the proangiogenic miR-126-3p/-5p may play a role in CVD. Animal studies established miR-126 to be pro-angiogenic. We hypothesised miR-126-3p/-5p are reduced in T1DM whilst pro-inflammatory cytokines are increased.

Methods

29 well controlled, T1DM patients without CVD and 20 healthy controls (HCs) were studied. MiR-126-3p/-5p were assayed in plasma and peripheral blood mononuclear cells (PBMCs) whilst Chemokine C-X-C Receptor 1/2 (CXCR1/2) mRNA in PBMCs by real-time quantitative PCR. Cytokines were assayed by the Mesoscale Discovery. Ingenuity Pathway Analysis (IPA) was used to predict target genes, cellular functions and pathological states regulated by miR-126-3p/-5p. IPA generated both direct and indirect causations between different targets and analysed whether these effects would be inhibitory or stimulatory based on the published evidence.

Results

T1DM patients had a relatively good diabetic control (HbA1c = 7.4 ± 0.7% or 57.3 ± 7.6 mmol/mol). Homeostatic cytokine IL-7, pro-inflammatory cytokines IL-8 and TNF-α, and vascular endothelial growth factor-C (VEGF-C) were increased in T1DM, versus HCs; p = 0.008, p = 0.003, p = 0.041 and p = 0.013 respectively. MiR-126-5p was significantly upregulated in PBMCs in T1DM versus HCs; p = 0.01, but not in plasma. MiR-126-3p was unchanged. CXCR1/2 were elevated in T1DM versus HCs; p = 0.009 and p < 0.001 respectively. MiR-126-5p was positively correlated with CXCR1/2, and with HbA1c whilst negatively correlated with circulating endothelial progenitor cells (CD34⁺CD133⁺CD45^dim) and fibronectin adhesion assay in a combined group of T1DM patients and HCs; p = 0.028 p = 0.049 p = 0.035 p = 0.047 and p = 0.004 respectively. IPA predicted miR-126-5p to be anti-inflammatory through the inhibition of chemokine C–C motif ligand 27, chymotrypsin-like elastase 2A and IL-7, whilst miR-126-3p had no direct anti-inflammatory effect. Simultaneously IPA predicted IL-7 as the most upstream cytokine target.

Conclusions

T1DM without apparent CVD or diabetic complications is an inflammatory state characterised not only by raised pro-inflammatory cytokines but also by increased receptor CXCR1/2 and miR-126-5p. MiR-126-5p upregulation may represent a compensatory response. Pro-miR-126-5p therapies or anti-IL-7 therapies may be a new option to reduce both inflammation and CVD risk in T1DM. Further research is required in a large prospective study in patients with T1DM.

Transcriptional networks in at-risk individuals identify signatures of type 1 diabetes progression

Type 1 diabetes (T1D) is a disease of insulin deficiency that results from autoimmune destruction of pancreatic islet β cells. The exact cause of T1D remains unknown, although asymptomatic islet autoimmunity lasting from weeks to years before diagnosis raises the possibility of intervention before the onset of clinical disease. The number, type, and titer of islet autoantibodies are associated with long-term disease risk but do not cause disease, and robust early predictors of individual progression to T1D onset remain elusive. The Environmental Determinants of Diabetes in the Young (TEDDY) consortium is a prospective cohort study aiming to determine genetic and environmental interactions causing T1D. Here, we analyzed longitudinal blood transcriptomes of 2013 samples from 400 individuals in the TEDDY study before both T1D and islet autoimmunity. We identified and interpreted age-associated gene expression changes in healthy infancy and age-independent changes tracking with progression to both T1D and islet autoimmunity, beginning before other evidence of islet autoimmunity was present. We combined multivariate longitudinal data in a Bayesian joint model to predict individual risk of T1D onset and validated the association of a natural killer cell signature with progression and the model's predictive performance on an additional 356 samples from 56 individuals in the independent Type 1 Diabetes Prediction and Prevention study. Together, our results indicate that T1D is characterized by early and longitudinal changes in gene expression, informing the immunopathology of disease progression and facilitating prediction of its course.

Dual Role of Interleukin-10 in Murine NZB/W F1 Lupus

As a key anti-inflammatory cytokine, IL-10 is crucial in preventing inflammatory and autoimmune diseases. However, in human and murine lupus, its role remains controversial. Our aim was to understand regulation and immunologic effects of IL-10 on different immune functions in the setting of lupus. This was explored in lupus-prone NZB/W F1 mice in vitro and vivo to understand IL-10 effects on individual immune cells as well as in the complex in vivo setting. We found pleiotropic IL-10 expression that largely increased with progressing lupus, while IL-10 receptor (IL-10R) levels remained relatively stable. In vitro experiments revealed pro- and anti-inflammatory IL-10 effects. Particularly, IL-10 decreased pro-inflammatory cytokines and slowed B cell proliferation, thereby triggering plasma cell differentiation. The frequent co-expression of ICOS, IL-21 and cMAF suggests that IL-10-producing CD4 T cells are important B cell helpers in this context. In vitro and in vivo effects of IL-10 were not fully concordant. In vivo IL-10R blockade slightly accelerated clinical lupus manifestations and immune dysregulation. Altogether, our side-by-side in vitro and in vivo comparison of the influence of IL-10 on different aspects of immunity shows that IL-10 has dual effects. Our results further reveal that the overall outcome may depend on the interplay of different factors such as target cell, inflammatory and stimulatory microenvironment, disease model and state. A comprehensive understanding of such influences is important to exploit IL-10 as a therapeutic target.

Treg Enhancing Therapies to Treat Autoimmune Diseases

Regulatory T cells (Tregs) are a small yet critical subset of CD4+ T cells, which have the role of maintaining immune homeostasis by, for example, regulating self-tolerance, tumor immunity, anti-microbial resistance, allergy and transplantation rejection. The suppressive mechanisms by which Tregs function are varied and pleiotropic. The ability of Tregs to maintain self-tolerance means they are critical for the control and prevention of autoimmune diseases. Irregularities in Treg function and number can result in loss of tolerance and autoimmune disease. Restoring immune homeostasis and tolerance through the promotion, activation or delivery of Tregs has emerged as a focus for therapies aimed at curing or controlling autoimmune diseases. Such therapies have focused on the Treg cell subset by using drugs to suppress T effector cells and promote Tregs. Other approaches have trialed inducing tolerance by administering the autoantigen via direct administration, by transient expression using a DNA vector, or by antigen-specific nanoparticles. More recently, cell-based therapies have been developed as an approach to directly or indirectly enhance Treg cell specificity, function and number. This can be achieved indirectly by transfer of tolerogenic dendritic cells, which have the potential to expand antigen-specific Treg cells. Treg cells can be directly administered to treat autoimmune disease by way of polyclonal Tregs or Tregs transduced with a receptor with high affinity for the target autoantigen, such as a high affinity T cell receptor (TCR) or a chimeric antigen receptor (CAR). This review will discuss the strategies being developed to redirect autoimmune responses to a state of immune tolerance, with the aim of the prevention or amelioration of autoimmune disease.

Lower risk of primary Sjogren's syndrome in patients with dengue virus infection: a nationwide cohort study in Taiwan

The data concerning the association between dengue viruses (DV) infection and autoimmune diseases (ADs) remain unclear and are scarce. This nationwide population-based cohort study assessed the risk of ADs among patients with DV infection. We analyzed Taiwanese medical data from the Registry of the National Notifiable Disease Reporting System of Taiwan’s Centers for Disease Control between 1998 and 2015 and identified patients with DV infection. From the entire general population data in the National Health Insurance Research Database, we randomly selected a comparison cohort that was individual matching by age, sex, residence, and index date. We analyzed the risk of ADs using a Cox proportional hazards regression model stratified by sex, age, and residence. We enrolled 29,365 patients with DV infection (50.68% men; mean age, 44.13 years) and 117,460 age-, sex-, and residence-matched controls in the present study. The incidence rates of organ-specific ADs were nonsignificantly higher in the DV cohort than in the non-DV control cohort. An approximately 70% lower risk of primary Sjogren syndrome (pSS) was evident in the DV cohort than in the non-DV control cohort with an adjusted hazard ratio of 0.30 (95% confidence interval 0.13–0.67) after adjusting for comorbidities in matched design. By contrast, the other systemic ADs were nonsignificantly lower in the DV cohort than in the non-DV control cohort. This nationwide long-term cohort study demonstrated that patients with DV infection had a lower risk of primary Sjogren syndrome than those without DV infection.

Key Points • This retrospective, longitudinal cohort observational study shows that patients with DV infection had a lower risk of pSS than those without DV infection. • The DV cohort had an approximately 70% lower risk of pSS than the control group, with a multivariate-adjusted HR of 0.30. • On the basis of this result, we contended that DV infection has a protective effect that reduces the risk of pSS.

Feasibility of Localized Metabolomics in the Study of Pancreatic Islets and Diabetes

(1) Background: Disruption of insulin production by native or transplanted pancreatic islets caused by auto/allo-immunity leads to hyperglycemia, a serious health condition and important therapeutic challenge due to the lifelong need for exogeneous insulin administration. Early metabolic biomarkers can prompt timely interventions to preserve islet function, but reliable biomarkers are currently lacking. We explored the feasibility of "localized metabolomics" where initial biomarker discovery is made in aqueous humor samples for further validation in the circulation. (2) Methods: We conducted non-targeted metabolomic studies in parallel aqueous humor and plasma samples from diabetic and nondiabetic mice. Metabolite levels and associated pathways were compared in both compartments as well as to an earlier longitudinal dataset in hyperglycemia-progressor versus non-progressor non-obese diabetic (NOD) mice. (3) Results: We confirmed that aqueous humor samples can be used to assess metabolite levels. About half of the identified metabolites had well-correlated levels in the aqueous humor and plasma. Several plasma metabolites were significantly different between diabetic and nondiabetic animals and between males and females, and many of them were correlated with the aqueous humor. (4) Conclusions: This study provides proof-of-concept evidence that aqueous humor samples enriched with islet-related metabolites and representative of the immediate islet microenvironment following intraocular islet transplant can be used to assess metabolic changes that could otherwise be overlooked in the general circulation. The findings support localized metabolomics, with and without intraocular islet transplant, to identify biomarkers associated with diabetes and islet allograft rejection.

Viruses and Autoimmunity: A Review on the Potential Interaction and Molecular Mechanisms

For a long time, viruses have been shown to modify the clinical picture of several autoimmune diseases, including type 1 diabetes (T1D), systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), Sjögren’s syndrome (SS), herpetic stromal keratitis (HSK), celiac disease (CD), and multiple sclerosis (MS). Best examples of viral infections that have been proposed to modulate the induction and development of autoimmune diseases are the infections with enteric viruses such as Coxsackie B virus (CVB) and rotavirus, as well as influenza A viruses (IAV), and herpesviruses. Other viruses that have been studied in this context include, measles, mumps, and rubella. Epidemiological studies in humans and experimental studies in animal have shown that viral infections can induce or protect from autoimmunopathologies depending on several factors including genetic background, host-elicited immune responses, type of virus strain, viral load, and the onset time of infection. Still, data delineating the clear mechanistic interaction between the virus and the immune system to induce autoreactivity are scarce. Available data indicate that viral-induced autoimmunity can be activated through multiple mechanisms including molecular mimicry, epitope spreading, bystander activation, and immortalization of infected B cells. Contrarily, the protective effects can be achieved via regulatory immune responses which lead to the suppression of autoimmune phenomena. Therefore, a better understanding of the immune-related molecular processes in virus-induced autoimmunity is warranted. Here we provide an overview of the current understanding of viral-induced autoimmunity and the mechanisms that are associated with this phenomenon.

The biological effects of the hypolipidaemic drug probucol microcapsules fed daily for 4 weeks, to an insulin-resistant mouse model: potential hypoglycaemic and anti-inflammatory effects

Probucol (PB) is an hypolipidaemic drug with potential antidiabetic effects. We showed recently using in vitro studies that when PB was incorporated with stabilising lipophilic bile acids and microencapsulated using the polymer sodium alginate, the microcapsules showed good stability but poor and irregular PB release. This suggests that PB microcapsules may exhibit better release profile and hence better absorption, if more hydrophilic bile acids were used, such as ursodeoxycholic acid (UDCA). Accordingly, this study aimed to produce PB-UDCA microcapsules and examine PB absorption and antidiabetic effects in our mouse-model of insulin-resistance and diabetes (fed high-fat diet; HFD). The study also aimed to examine the effects of the microcapsules on the bile acid profile. Healthy mice (fed low-fat diet; LFD) were used as control. Seventy mice were randomly allocated into seven equal groups: LFD, HFD given empty microcapsules, HFD given metformin (M), HFD given standard-dose probucol (PB-SD), HFD given high-dose probucol (PB-H), HFD given UDCA microcapsules and HFD given PB-UDCA microcapsules. Blood glucose (BG), inflammatory biomarkers (TNF-α, IFN-γ, IL-1β, IL-6, IL-10, IL-12 and IL-17), plasma cholesterol, non-esterified fatty acids and triglycerides were analysed together with plasma bile acid and probucol concentrations. PB-UDCA microcapsules reduced BG in HFD mice, but did not reduce inflammation or improve lipid profile, compared with positive control (HFD) group. Although PB-UDCA microcapsules did not exert hypolipidaemic or antiinflammatory effects, they resulted in significant hypoglycaemic effects in a mouse model of insulin resistance, which suggests potential applications in insulin-resistance and glucose haemostasis.

Human milk oligosaccharides protect against the development of autoimmune diabetes in NOD-mice

Development of Type 1 diabetes (T1D) is influenced by non-genetic factors, such as optimal microbiome development during early life that "programs" the immune system. Exclusive and prolonged breastfeeding is an independent protective factor against the development of T1D, likely via bioactive components. Human Milk Oligosaccharides (HMOS) are microbiota modulators, known to regulate immune responses directly. Here we show that early life provision (only for a period of six weeks) of 1% authentic HMOS (consisting of both long-chain, as well as short-chain structures), delayed and suppressed T1D development in non-obese diabetic mice and reduced development of severe pancreatic insulitis in later life. These protective effects were associated with i) beneficial alterations in fecal microbiota composition, ii) anti-inflammatory microbiota-generating metabolite (i.e. short chain fatty acids (SCFAs)) changes in fecal, as well as cecum content, and iii) induction of anti-diabetogenic cytokine profiles. Moreover, in vitro HMOS combined with SCFAs induced development of tolerogenic dendritic cells (tDCs), priming of functional regulatory T cells, which support the protective effects detected in vivo. In conclusion, HMOS present in human milk are therefore thought to be vital in the protection of children at risk for T1D, supporting immune and gut microbiota development in early life.

Neutralization Versus Reinforcement of Proinflammatory Cytokines to Arrest Autoimmunity in Type 1 Diabetes

As physiological pathways of intercellular communication produced by all cells, cytokines are involved in the pathogenesis of inflammatory insulitis as well as pivotal mediators of immune homeostasis. Proinflammatory cytokines including interleukins, interferons, transforming growth factor-β, tumor necrosis factor-α, and nitric oxide promote destructive insulitis in type 1 diabetes through amplification of the autoimmune reaction, direct toxicity to β-cells, and sensitization of islets to apoptosis. The concept that neutralization of cytokines may be of therapeutic benefit has been tested in few clinical studies, which fell short of inducing sustained remission or achieving disease arrest. Therapeutic failure is explained by the redundant activities of individual cytokines and their combinations, which are rather dispensable in the process of destructive insulitis because other cytolytic pathways efficiently compensate their deficiency. Proinflammatory cytokines are less redundant in regulation of the inflammatory reaction, displaying protective effects through restriction of effector cell activity, reinforcement of suppressor cell function, and participation in islet recovery from injury. Our analysis suggests that the role of cytokines in immune homeostasis overrides their contribution to β-cell death and may be used as potent immunomodulatory agents for therapeutic purposes rather than neutralized.

Galega officinalis extract regulate the diabetes mellitus related violations of proliferation, functions and apoptosis of leukocytes

BACKGROUND

An impaired leukocytes function is the factor causing the susceptibility of patients with diabetes mellitus to infections. The outmost importance for the understanding of the immunological processes involved in diabetes pathogenesis is to give the characteritics of the immunological profile and changes therein, during the course of desease. Long-used in folk medicine to treat diabetes Galega officinalis L. has been chosen for the correction of the immune system dysfunction.

METHODS

The experiments were conducted on male Wistar rats. Fractionation of bone marrow cells suspension was performed in a three-layer ficoll-sodium amidotrizoate density gradient. The lymphocytic-granulocytic cells proliferative activity was studied using enzyme immunoassay with 5-bromo-2'-deoxyuridine (BrdU). For staining of bone marrow preparations May-Gruenwald-Romanowsky-Giemsa (Pappenheim) method was used. To evaluate the content of cationic proteins and myeloperoxidase in neutrophilic leukocytes cytochemical studies were performed. Content of tumor necrosis factor alpha was carried out by immuno-enzymatic analysis. Lymphocytes apoptosis was examined by fluorescent analysis using annexin V.

RESULTS

Diabetes mellitus development was accompanied with violation of neutrophils and lymphocytes proliferation, increased activity of myeloperoxidase and enhanced apoptosis process. Administration of Galega officinalis extract under the condition of diabetes promotes the restoration of neutrophils bone marrow pool and the reduction of lymphoblasts number and causes inhibition of the lymphocytes apoptosis process.

CONCLUSIONS

Investigated medicine has a pronounced immunocorrective effect under the conditions of diabetes mellitus and can become the basis for creating a new generation of antidiabetic drugs.

TNF, TNF inducers, and TNFR2 agonists: A new path to type 1 diabetes treatment

In the past decade, interest in the century-old tuberculosis vaccine, bacillus Calmette-Guerin (BCG), has been revived for potential new therapeutic uses in type 1 diabetes and other forms of autoimmunity. Diverse clinical trials are now proving the value of BCG in prevention and treatment of type 1 diabetes, in the treatment of new onset multiple sclerosis and other immune conditions. BCG contains the avirulent tuberculosis strain Mycobacterium bovis, a vaccine originally developed for tuberculosis prevention. BCG induces a host response that is driven in part by tumour necrosis factor (TNF). Induction of TNF through BCG vaccination or through selective agonism of TNF receptor 2 (TNFR2) has 2 desired cellular immune effects: (1) selective death of autoreactive T cells and (2) expansion of beneficial regulatory T cells (Tregs). In human clinical trials in both type 1 diabetes and multiple sclerosis, administration of the BCG vaccine to diseased adults has shown great promise. In a Phase I trial in advanced type 1 diabetes (mean duration of diabetes 15 years), 2 BCG vaccinations spaced 4 weeks apart selectively eliminated autoreactive T cells, induced beneficial Tregs, and allowed for a transient and small restoration of insulin production. The advancing global clinical trials using BCG combined with mechanistic data on BCGs induction of Tregs suggest value in this generic agent and possible immune reversal of the type 1 diabetic autoimmune process.

Antibody Neutralization of CXCL10 in Vivo Is Dependent on Binding to Free and Not Endothelial-bound Chemokine: IMPLICATIONS FOR THE DESIGN OF A NEW GENERATION OF ANTI-CHEMOKINE THERAPEUTIC ANTIBODIES

To improve our understanding of properties that confer successful inhibition of chemokines in vivo, we analyzed anti-murine CXCL10 monoclonal antibodies (mAb) having different characteristics. 1B6 displayed potent inhibition of cell recruitment in vitro with an IC50 of 0.5 nm but demonstrated little efficacy in various animal models of human disease. On the contrary, 1F11 showed efficacy in several models of inflammation yet was less potent at inhibiting chemotaxis in vitro with an IC50 of 21 nm Furthermore, we observed that 1B6 displayed a rapid dose-dependent clearance (t½ 10-60 h) in contrast to 1F11, which presented a dose-proportional pharmacokinetic profile and a half-life of 12 days. Moreover, 1B6 recognized glycosaminoglycan (GAG)-bound CXCL10, resulting in target-mediated clearance, which was corroborated using CXCL10-deficient mice. In contrast to 1B6, 1F11 inhibited the interaction of CXCL10 with GAGs, did not recognize GAG-bound CXCL10, and did not display target-mediated drug disposition. Confirming previous animal studies, 1B6 was poor at reversing glycemia in a model of type 1 diabetes, whereas 1F11 induced early and prolonged control of diabetes. Furthermore, when using 1A4, a subsequently generated anti-mCXCL10 mAb that shares the property with 1F11 of being unable to recognize CXCL10 immobilized on GAG, we observed a similar superior control of diabetes as compared with 1B6. We therefore concluded that targeting chemokines with antibodies such as 1B6 that recognize the more abundant GAG-bound form of the chemokine may not be the optimal strategy to achieve disease control.

A roadmap of the generation of neoantigens as targets of the immune system in type 1 diabetes

Type 1 diabetes (T1D) is an autoimmune disease characterized by the selective destruction of the insulin-producing beta cells. Beta cell dysfunction caused by an inflammatory microenvironment is believed to trigger the peripheral activation of CD4 and CD8 autoreactive T cells. This review will compile post-transcriptional and post-translational modifications (PTM) involved in the generation of beta cell neoantigens and proposes a reconstruction of the sequence of events connecting environmental changes and autoimmunity.

Therapeutic antibodies that target inflammatory cytokines in autoimmune diseases

Inflammatory cytokines are key regulators of immune responses. Persistent and excessive production of inflammatory cytokines underscores the development of autoimmune diseases. Therefore, neutralizing inflammatory cytokines or antagonizing their receptor function is considered as a useful therapeutic strategy to treat autoimmune diseases. To achieve the success of such a strategy, understanding of the complex actions of these cytokines and cytokine networks is required. In this review we focus on four inflammatory cytokines--tumor necrosis factor α (TNFα), interleukin-6 (IL-6), IL-23 and IL-17--and dissect how the dysregulation of these cytokines regulates autoimmune diseases. On the basis of pre-clinical and clinical data, we specifically discuss the therapeutic rationale for targeting these cytokines and describe the potential adverse effects.

Anti-CD3/Anti-CXCL10 Antibody Combination Therapy Induces a Persistent Remission of Type 1 Diabetes in Two Mouse Models

Anti-CD3 therapy of type 1 diabetes results in a temporary halt of its pathogenesis but does not constitute a permanent cure. One problem is the reinfiltration of islets of Langerhans with regenerated, autoaggressive lymphocytes. We aimed at blocking such a reentry by neutralizing the key chemokine CXCL10. Combination therapy of diabetic RIP-LCMV and NOD mice with anti-CD3 and anti-CXCL10 antibodies caused a substantial remission of diabetes and was superior to monotherapy with anti-CD3 or anti-CXCL10 alone. The combination therapy prevented islet-specific T cells from reentering the islets of Langerhans and thereby blocked the autodestructive process. In addition, the local immune balance in the pancreas was shifted toward a regulatory phenotype. A sequential temporal inactivation of T cells and blockade of T-cell migration might constitute a novel therapy for patients with type 1 diabetes.

Restoration of Na+/H+ exchanger NHE3-containing macrocomplexes ameliorates diabetes-associated fluid loss

Diarrhea is one of the troublesome complications of diabetes, and the underlying causes of this problem are complex. Here, we investigated whether altered electrolyte transport contributes to diabetic diarrhea. We found that the expression of Na+/H+ exchanger NHE3 and several scaffold proteins, including NHE3 regulatory factors (NHERFs), inositol trisphosphate (IP₃) receptor-binding protein released with IP₃ (IRBIT), and ezrin, was decreased in the intestinal brush border membrane (BBM) of mice with streptozotocin-induced diabetes. Treatment of diabetic mice with insulin restored intestinal NHE3 activity and fluid absorption. Molecular analysis revealed that NHE3, NHERF1, IRBIT, and ezrin form macrocomplexes, which are perturbed under diabetic conditions, and insulin administration reconstituted these macrocomplexes and restored NHE3 expression in the BBM. Silencing of NHERF1 or IRBIT prevented NHE3 trafficking to the BBM and insulin-dependent NHE3 activation. IRBIT facilitated the interaction of NHE3 with NHERF1 via protein kinase D2-dependent phosphorylation. Insulin stimulated ezrin phosphorylation, which enhanced the interaction of ezrin with NHERF1, IRBIT, and NHE3. Additionally, oral administration of lysophosphatidic acid (LPA) increased NHE3 activity and fluid absorption in diabetic mice via an insulin-independent pathway. Together, these findings indicate the importance of NHE3 in diabetic diarrhea and suggest LPA administration as a potential therapeutic strategy for management of diabetic diarrhea.

The role of Th17-associated cytokines in the pathogenesis of experimental autoimmune uveitis (EAU)

The proinflammatory and pathogenic function of Th17 cells in autoimmune diseases have been established but the mechanism by which such cells cause disease remains to be determined. Inflammatory cytokines produced by Th17 cells may either promote or inhibit disease development. The major cytokines produced by the uveitogenic T cells, such as IL-17 and IL-22, are not always pathogenic, and the disease-inducing ability of pathogenic T cells is not immediately correlated to the amount of cytokine they produce. Future studies identifying factors causing increased Th17 responses and determining the types of cells that regulating Th17 autoreactive T cells should facilitate our effort of understanding Th17-mediated disease pathogenesis.

Enterovirus and type 1 diabetes: What is the matter?

A complex interaction of genetic and environmental factors can trigger the immune-mediated mechanism responsible for type 1 diabetes mellitus (T1DM) establishment. Environmental factors may initiate and possibly sustain, accelerate, or retard damage to β-cells. The role of environmental factors in this process has been exhaustive studied and viruses are among the most probable ones, especially enteroviruses. Improvements in enterovirus detection methods and randomized studies with patient follow-up have confirmed the importance of human enterovirus in the pathogenesis of T1DM. The genetic risk of T1DM and particular innate and acquired immune responses to enterovirus infection contribute to a tolerance to T1DM-related autoantigens. However, the frequency, mechanisms, and pathways of virally induced autoimmunity and β-cell destruction in T1DM remain to be determined. It is difficult to investigate the role of enterovirus infection in T1DM because of several concomitant mechanisms by which the virus damages pancreatic β-cells, which, consequently, may lead to T1DM establishment. Advances in molecular and genomic studies may facilitate the identification of pathways at earlier stages of autoimmunity when preventive and therapeutic approaches may be more effective.

Interplay among cytokines and T cell subsets in the progression and control of immune-mediated diseases

Cytokines serve as key mediators of inflammation and tissue damage in a variety of immune-mediated disorders. The induction, progression, and resolution of inflammation in such disorders are characterized by a dynamic balance between both the pro-inflammatory and anti-inflammatory cytokines as well as the pathogenic and protective T cell subsets. Over the past two decades, the roles of the interleukin-17 (IL-17) /IL-23 axis and the T helper 17 (Th17)/ T regulatory (Treg) cell balance in the pathogenesis of autoimmunity and other inflammatory diseases have extensively been analyzed, and their significance validated. However, these studies, coupled with others devoted to well-established Th1/Th2 cytokines, have unraveled some challenging issues including the dual action of cytokines and the plasticity of T cell subsets. Nevertheless, major positive advances have also been made regarding cytokines and T cell subsets as therapeutic targets/agents. In this special issue, "Cytokines in Immune Pathology and Therapy," leading experts have shared their research work and perspectives on the roles of cytokines in the development and control of immune-mediated diseases. An outline of 14 articles in the first volume is presented here. The second volume will follow soon.

TLR2- and Dectin 1-associated innate immune response modulates T-cell response to pancreatic β-cell antigen and prevents type 1 diabetes

The progression of autoimmune diseases is dictated by deviations in the fine balance between proinflammatory versus regulatory responses, and pathogen recognition receptors (PRRs) play a key role in maintaining this balance. Previously, we have reported that ligation of Toll-like receptor 2 (TLR2) and Dectin 1 on antigen-presenting cells by zymosan results in a regulatory immune response that prevents type 1 diabetes (T1D). Here, we show that TLR2 and Dectin 1 engagement by zymosan promotes regulatory T-cell (Treg) responses against the pancreatic β-cell-specific antigen (Ag). Unlike the TLR4 ligand, bacterial lipopolysaccharide, which induced proinflammatory cytokines and pathogenic T cells, zymosan induced a mixture of pro- and anti-inflammatory factors and Tregs, both in vitro and in vivo. Ag-specific T cells that are activated using zymosan-exposed dendritic cells (DCs) expressed Foxp3 and produced large amounts of IL-10, TGF-β1, and IL-17. NOD mice that received β-cell-Ag-loaded, zymosan-exposed DCs showed delayed hyperglycemia. Injection of NOD mice at the prediabetic age and early hyperglycemic stage with β-cell-Ag, along with zymosan, results in a superior protection of the NOD mice from diabetes as compared with mice that received zymosan alone. This therapeutic effect was associated with increased frequencies of IL-10-, IL-17-, IL-4-, and Foxp3-positive T cells, especially in the pancreatic lymph nodes. These results show that zymosan can be used as an immune regulatory adjuvant for modulating the T-cell response to pancreatic β-cell-Ag and reversing early-stage hyperglycemia in T1D.

Novel insights into the immunomodulatory role of the dendritic cell and macrophage-expressed C-type lectin MGL

Based on their ability to balance tolerance and inflammation, antigen presenting cells, such as dendritic cells and macrophages contribute to the maintenance of immune homeostasis as well as the instigation of immune activation. Acting as key sensors of tissue integrity and pathogen invasion, they are well equipped with a wide variety of pattern recognition receptors, to which the C-type lectin family also belongs. C-type lectins are glycan-binding receptors that mediate cell-cell communication and pathogen recognition, besides participating in the endocytosis of antigens for presentation to T cells and the fine-tuning of immune responses. Here we review the current state-of-the-art on the dendritic cell and macrophage-expressed C-type lectin macrophage galactose-type lectin (MGL), highlighting the binding specificities, signaling properties and modulation of innate and adaptive immunity by its human and murine orthologues.

Effect of biologically synthesized gold nanoparticles on alloxan-induced diabetic rats-an in vivo approach

Development of novel antidiabetic agents using various organic compounds and biomolecules has been in practice for a long time. Recently, nanomaterials are also being used in antidiabetic studies for their unique properties such as small size, biocompatibility and ability to penetrate cell membrane for carrying drugs. Herein, in vivo antidiabetic activity of gold nanoparticles (AuNPs) synthesized using the antidiabetic potent plant Gymnema sylvestre R. Br on wistar albino rats has been evaluated. The formation of AuNPs and their morphology were confirmed using spectroscopic and microscopic analyses, respectively. The treatment of AuNPs has shown significant reduction in blood glucose level on diabetic rats. AuNPs were also tested for its anti-inflammatory effect by estimating the serum levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and high-sensitive C-reactive protein (CRP).

TNF-α and IFN-γ gene variation and genetic susceptibility to type 1 diabetes and its microangiopathic complications

Background

TNF-α has accelerating role in development of type 1 diabetes. Although an immunosupressor function and leading protecting role in T1DM also has been claimed for this pro-inflammatory cytokine. Over-expression of pro-inflammatory and type 1 cytokines (Th1, like IFN-γ) drive insulitis toward the destructive form that leads to type 1 diabetes (T1DM). Among type 1 cytokines only IFN-γ has been detectable in the islet β cells. In deletion studies IFN-γ was also the only Th1 cytokine for which its ablation or blockade caused delayed or decreased incidence of T1DM.

Methods

Functional polymorphisms of TNF-α at position -308*G/A and at position +874*T/A of IFN-γ gene were employed as markers and the comparative distribution of derived genotypes/alleles were assessed in 248 British Caucasian T1DM patients and 118 healthy controls.

Results

There was no significant association between IFN-γ gene polymorphism and T1DM or the diabetic complication triad. There was a marginal association between TNF-α –308*G/A polymorphism in nephropaths (vs healthy controls) (p = 0.06), which its insignificancy may be due to survivor factor. No significant association was evident between the genotype/allele of the applied marker and T1DM or diabetic complication triad.

Conclusion

Our results are in contrast with previous reports suggesting that these polymorphisms are not related to T1DM. This study also underlines the importance of replication of association studies to confirm the previous interpretation.

TNF Receptor 2 and Disease: Autoimmunity and Regenerative Medicine

The regulatory cytokine tumor necrosis factor (TNF) exerts its effects through two receptors: TNFR1 and TNFR2. Defects in TNFR2 signaling are evident in a variety of autoimmune diseases. One new treatment strategy for autoimmune disease is selective destruction of autoreactive T cells by administration of TNF, TNF inducers, or TNFR2 agonism. A related strategy is to rely on TNFR2 agonism to induce T-regulatory cells (T_regs) that suppress cytotoxic T cells. Targeting TNFR2 as a treatment strategy is likely superior to TNFR1 because of its more limited cellular distribution on T cells, subsets of neurons, and a few other cell types, whereas TNFR1 is expressed throughout the body. This review focuses on TNFR2 expression, structure, and signaling; TNFR2 signaling in autoimmune disease; treatment strategies targeting TNFR2 in autoimmunity; and the potential for TNFR2 to facilitate end organ regeneration.

Low C-peptide levels and decreased expression of TNF and CD45 in children with high risk of type 1 diabetes

Type 1 diabetes (T1D) patients have numeral and functional defects in peripheral immune cells, but the pre-diabetic period is fairly uncharacterized. Our aim was to analyze expression of immunological markers in T1D high risk children and relate it to clinical/immunological parameters. Children from ABIS (All Babies in Southeast Sweden) with ≥2 diabetes related autoantibodies were considered at high risk. Age-matched controls and new-onset T1D patients were included. Expression of genes related to immune cell function and different arms of the immune system was assessed in peripheral blood mononuclear cells using PCR array. Risk children had lower TNF and CD45, and although there were few differences between the groups, expression of many genes differed when comparing children with regard to residual insulin secretion. Hence, expression of immune related genes seemed related not only to the autoimmune process but rather to residual β-cell function, which was decreased already during the pre-diabetic phase.

Blockade but not overexpression of the junctional adhesion molecule C influences virus-induced type 1 diabetes in mice

Type 1 diabetes (T1D) results from the autoimmune destruction of insulin-producing beta-cells in the pancreas. Recruitment of inflammatory cells is prerequisite to beta-cell-injury. The junctional adhesion molecule (JAM) family proteins JAM-B and JAM–C are involved in polarized leukocyte transendothelial migration and are expressed by vascular endothelial cells of peripheral tissue and high endothelial venules in lympoid organs. Blocking of JAM-C efficiently attenuated cerulean-induced pancreatitis, rheumatoid arthritis or inflammation induced by ischemia and reperfusion in mice. In order to investigate the influence of JAM-C on trafficking and transmigration of antigen-specific, autoaggressive T-cells, we used transgenic mice that express a protein of the lymphocytic choriomeningitis virus (LCMV) as a target autoantigen in the β-cells of the islets of Langerhans under the rat insulin promoter (RIP). Such RIP-LCMV mice turn diabetic after infection with LCMV. We found that upon LCMV-infection JAM-C protein was upregulated around the islets in RIP-LCMV mice. JAM-C expression correlated with islet infiltration and functional beta-cell impairment. Blockade with a neutralizing anti-JAM-C antibody reduced the T1D incidence. However, JAM-C overexpression on endothelial cells did not accelerate diabetes in the RIP-LCMV model. In summary, our data suggest that JAM-C might be involved in the final steps of trafficking and transmigration of antigen-specific autoaggressive T-cells to the islets of Langerhans.

Tumor Necrosis Factor-α Gene Polymorphisms in FMF and Their Association With Amyloidosis

Familial Mediterranean fever (FMF) is an autosomal recessive disorder characterized by periodic provocative attacks of fever with peritonitis, pleuritis, arthritis, or eriseplemya. Tumor necrosis factor-α (TNF-α) plays an important role in the regulation of the immune response as a part of the cytokine network, including activation of macrophages and apoptosis. We investigated the possible association of TNF-α promoter −1031T/C and −308G/A polymorphisms in 86 FMF patients carrying M694 V homozygous mutation and 100 matched healthy controls both from Iranian Azeri Turks. Our data showed that patients with TNF-α −308 GG are more susceptible to the development of amyloidosis and arthritis ( P value <.05). These data also showed that the frequency of TNF-α −308 A allele is considerably low among patients with amyloidosis, and it may have protective role among them (odds ratio [OR] = 0.083, χ2 = 5.46, P value = .003). Further evaluation of this polymorphism may be important and need further studies.

Tumor necrosis factor-associated susceptibility to type 1 diabetes is caused by linkage disequilibrium with HLA-DR3 haplotypes

Tumor necrosis factor-α (TNF-α) is an important proinflammatory cytokine involved in the pathogenesis of autoimmune type 1 diabetes (T1D). The TNF gene locus is located in the major histocompatibility complex (MHC) class III region and its genetic polymorphisms have been reported to be associated with T1D. However, it is not clear whether these associations are primary or caused by their linkage disequilibrium with other predisposing genes within the MHC. We have tested 2 TNF-α single nucleotide polymorphisms at positions -308G/A and -238G/A in the 5' untranslated region and a (GT)n microsatellite TNFa in the North Indian healthy population and T1D patients with known HLA-A-B-DR-DQ haplotypes. The allele frequencies of TNFa5, -308A, and -238G were determined to be significantly increased among patients compared with controls. Although the observed positive association of -238G was caused by its presence on all 3 DR3(+) groups, namely, B8-DR3-DQ2, B50-DR3-DQ2, and B58-DR3-DQ2 haplotypes associated with T1D in this population, the increase of the -308A allele was caused by its association with the latter 2 haplotypes. On the other hand, TNF -308G occurred on B8-DR3 haplotypes along with -238G and TNFa5 alleles, particularly in T1D patients with late disease onset (at >20 years of age). These results indicate that TNF associations with T1D are caused by their linkage disequilibrium with specific HLA-DR3-DQ2 haplotypes in the Indian population. Because polymorphisms in the promoter region regulate TNF expression levels (e.g., -308A), they retain crucial immunological significance in the development of T1D and its management.

Targeting pre-ligand assembly domain of TNFR1 ameliorates autoimmune diseases - an unrevealed role in downregulation of Th17 cells

The pre-ligand assembly domain (PLAD) of tumor necrosis factor receptors mediates specific ligand-independent receptor assembly and subsequent signaling. However, the physiological role of PLAD in the regulation of TNFR-mediated immune responses in autoimmunity is still unclear. By using the recombinant PLAD.Fc protein to block TNFR1 assembly, we demonstrated that PLAD.Fc treatment significantly reduced the TNFR1-driving proinflammatory cytokines and protected NOD mice from diabetes. Strikingly, Th17 differentiation was significantly inhibited in PLAD.Fc-treated NOD and TNFR1-deficient mice, indicating a TNFR1-dependent Th17 development. PLAD.Fc-modulated effects on DCs, in terms of the downregulation of Th17-inducing cytokines, IL-6 and TGF-β, explained the potential mechanism for Th17 suppression. Finally, we provided an additional result that PLAD.Fc administration diminished the infiltration of Th17 cells in the central nervous system and ameliorated the experimental autoimmune encephalomyelitis in mice. Collectively, these data demonstrated that targeting PLAD of TNFR1 provides protection from autoimmune diseases through the downregulation of Th17 and suggested a therapeutic potential of PLAD-modulation in TNF-involved inflammatory diseases.

Cytokines in autoimmunity: role in induction, regulation, and treatment

Cytokines play a pivotal role in the pathogenesis of autoimmune diseases. The precise triggers for the breakdown of self-tolerance and the subsequent events leading to the induction of pathogenic autoimmune responses remain to be defined for most of the naturally occurring autoimmune diseases. Studies conducted in experimental models of human autoimmune diseases and observations in patients have revealed a general scheme in which proinflammatory cytokines contribute to the initiation and propagation of autoimmune inflammation, whereas anti-inflammatory cytokines facilitate the regression of inflammation and recovery from acute phase of the disease. This idea is embodied in the T helper (Th) 1/Th2 paradigm, which over the past two decades has had a major influence on our thinking about the role of cytokines in autoimmunity. Interestingly, over the past decade, the interleukin (IL)-17/IL-23 axis has rapidly emerged as the new paradigm that has compelled us to critically re-examine the cytokine-driven immune events in the pathogenesis and treatment of autoimmunity. In this 2-volume special issue of the journal, leading experts have presented their research findings and viewpoints on the role of cytokines in the context of specific autoimmune diseases.

Small molecule CXCR3 antagonist NIBR2130 has only a limited impact on type 1 diabetes in a virus-induced mouse model

CXCL10 is one of the key chemokines involved in trafficking of autoaggressive T cells to the islets of Langerhans during the autoimmune destruction of beta cells in type 1 diabetes (T1D). Blockade of CXCL10 or genetic deletion of its receptor CXCR3 results in a reduction of T1D in animal models. As an alternative to the use of neutralizing monoclonal antibodies to CXCL10 or CXCR3 we evaluated the small molecule CXCR3 antagonist NIBR2130 in a virus-induced mouse model for T1D. We found that the overall frequency of T1D was not reduced in mice administered with NIBR2130. An initial slight delay of diabetes onset was not stable over time, because the mice turned diabetic upon removal of the antagonist. Accordingly, no significant differences were found in the islet infiltration rate and the frequency and activity of islet antigen-specific T cells between protected mice administered with NIBR2130 and control mice. Our data indicate that in contrast to direct inhibition of CXCL10, blockade of CXCR3 with the small molecule antagonist NIBR2130 has no impact on trafficking and/or activation of autoaggressive T cells and is not sufficient to prevent T1D.

Tumor necrosis factor induces GSK3 kinase-mediated cross-tolerance to endotoxin in macrophages

Endotoxin tolerance, a key mechanism for suppressing excessive inflammatory cytokine production, is induced by prior exposure of macrophages to Toll-like receptor (TLR) ligands. Induction of cross-tolerance to endotoxin by endogenous cytokines has not been investigated. Here we show that prior exposure to tumor necrosis factor (TNF) induced a tolerant state in macrophages, with less cytokine production after challenge with lipopolysaccharide (LPS) and protection from LPS-induced death. TNF-induced cross-tolerization was mediated by suppression of LPS-induced signaling and chromatin remodeling. TNF-induced cross-tolerance was dependent on the kinase GSK3, which suppressed chromatin accessibility and promoted rapid termination of signaling via the transcription factor NF-κB by augmenting negative feedback by the signaling inhibitors A20 and IκBα. Our results demonstrate an unexpected homeostatic function for TNF and a GSK3-mediated mechanism for the prevention of prolonged and excessive inflammation.

TLR2 signaling improves immunoregulation to prevent type 1 diabetes

Signaling through TLR2 promotes inflammation and modulates CD4(+) CD25(+) Tregs. We assessed mechanistically how this molecule would alter immunoregulation in type 1 diabetes (T1D). We also asked whether TLR2 may be involved in our recent discovery that viral infection can protect from autoimmune diabetes by expanding and invigorating Tregs. Treatment of prediabetic mice with a synthetic TLR2 agonist diminished T1D and increased the number and function of CD4(+) CD25(+) Tregs, also conferring DCs with tolerogenic properties. TLR2 ligation also promoted the expansion of Tregs upon culture with DCs and ameliorated their capacity to prevent the disease. Protection from T1D by lymphocytic choriomeningitis virus (LCMV) infection depended on TLR2. LCMV increased the frequency of CD4(+) CD25(+) Tregs and their production of TGF-β more significantly in WT than TLR2-deficient mice. Furthermore, LCMV infection in vivo or LCMV-infected DCs in vitro rendered, via TLR2, CD4(+) CD25(+) Tregs capable of diminishing T1D. We identify novel mechanisms by which TLR2 promotes immunoregulation and controls autoimmune diabetes in naïve or infected hosts. This work should help understand T1D etiology and develop novel immune-based therapeutic interventions.

Enterovirus infection induces cytokine and chemokine expression in insulin-producing cells

Despite evidence supporting an association between enterovirus (EV) infection and type 1 diabetes, the etiological mechanism(s) for EV-induced beta cell destruction is(are) not well understood. In this study, the effects of Coxsackievirus B (CVB) 1-6 on cell lysis and cytokine/chemokine expression in the insulinoma-1 (INS-1) beta cell line were investigated. Cytolysis was assessed using tissue culture infectious dose 50 (TCID(50)). Quantitative RT-PCR was used to measure viral RNA and mRNA of cytokines interferon (IFN)-α, IFN-β, IFN-γ, tumor necrosis factor (TNF)-α, and chemokine (C-X-C motif) ligand 10 (CXCL10), chemokine (C-C motif) ligand 2 (CCL2), and chemokine (C-C motif) ligand 5 (CCL5) in infected INS-1 cells. CVB2, 4, 5, and 6 lysed and replicated in INS-1 cells; TCID(50) was lowest for CVB5 and highest for CVB6. IFN-γ, CXCL10, and CCL5 mRNA levels all increased significantly following infection with CVB2, 4, 5, and 6 (P<0.05). CCL2 mRNA increased with CVB2, 5, and 6 (P<0.05), IFN-α mRNA increased with CVB5 infection (P<0.05), while TNF-α mRNA and IFN-β mRNA (P<0.001) increased with CVB2 infection. Dose-dependent effects of infection on cytokine mRNA levels were observed for all (P<0.01) except IFN-γ. Following inoculation of INS-1 cells with CVB1 and 3, viral RNA was not detected and cytokine/chemokine mRNA levels were unchanged. In conclusion, CVB2, 4, 5, and 6 induce dose-dependent cytokine and chemokine mRNA production from INS-1 cells suggesting that pro-inflammatory cytokine and chemokine secretion by beta cells is a potential mechanism for EV-induced beta cell damage in type 1 diabetes.

Type 1 Diabetes: Etiology, Immunology, and Therapeutic Strategies

Type 1 diabetes (T1D) is a chronic autoimmune disease in which destruction or damaging of the beta-cells in the islets of Langerhans results in insulin deficiency and hyperglycemia. We only know for sure that autoimmunity is the predominant effector mechanism of T1D, but may not be its primary cause. T1D precipitates in genetically susceptible individuals, very likely as a result of an environmental trigger. Current genetic data point towards the following genes as susceptibility genes: HLA, insulin, PTPN22, IL2Ra, and CTLA4. Epidemiological and other studies suggest a triggering role for enteroviruses, while other microorganisms might provide protection. Efficacious prevention of T1D will require detection of the earliest events in the process. So far, autoantibodies are most widely used as serum biomarker, but T-cell readouts and metabolome studies might strengthen and bring forward diagnosis. Current preventive clinical trials mostly focus on environmental triggers. Therapeutic trials test the efficacy of antigen-specific and antigen-nonspecific immune interventions, but also include restoration of the affected beta-cell mass by islet transplantation, neogenesis and regeneration, and combinations thereof. In this comprehensive review, we explain the genetic, environmental, and immunological data underlying the prevention and intervention strategies to constrain T1D.

Calcineurin/nuclear factor of activated T cells and MAPK signaling induce TNF-{alpha} gene expression in pancreatic islet endocrine cells

Cytokines contribute to pancreatic islet inflammation, leading to impaired glucose homeostasis and diabetic diseases. A plethora of data shows that proinflammatory cytokines are produced in pancreatic islets by infiltrating mononuclear immune cells. Here, we show that pancreatic islet α cells and β cells express tumor necrosis factor-α (TNF-α) and other cytokines capable of promoting islet inflammation when exposed to interleukin-1β (IL-1β). Cytokine expression by β cells was dependent on calcineurin (CN)/nuclear factor of activated T cells (NFAT) and MAPK signaling. NFAT associated with the TNF-α promoter in response to stimuli and synergistically activated promoter activity with ATF2 and c-Jun. In contrast, the β-cell-specific transcriptional activator MafA could repress NFAT-mediated TNF-α gene expression whenever C/EBP-β was bound to the promoter. NFAT differentially regulated the TNF-α gene depending upon the expression and MAPK-dependent activation of interacting basic leucine zipper partners in β cells. Both p38 and JNK were required for induction of TNF-α mRNA and protein expression. Collectively, the data show that glucose and IL-1β can activate signaling pathways, which control induction and repression of cytokines in pancreatic endocrine cells. Thus, by these mechanisms, pancreatic β cells themselves may contribute to islet inflammation and their own immunological destruction in the pathogenesis of diabetes.

CXCL10 promotes liver fibrosis by prevention of NK cell mediated hepatic stellate cell inactivation

Chemokines, such as CXCL10, promote hepatic inflammation in chronic or acute liver injury through recruitment of leukocytes to the liver parenchyma. The CXCL10 receptor CXCR3, which is expressed on a subset of leukocytes, plays an important part in Th1-dependent inflammatory responses. Here, we investigated the role of CXCL10 in chemically induced liver fibrosis. We used carbon tetrachloride (CCl(4)) to trigger chronic liver damage in wildtype C57BL/6 and CXCL10-deficient mice. Fibrosis severity was assessed by Sirius Red staining and intrahepatic leukocyte subsets were investigated by immunohistochemistry. We have further analyzed hepatic stellate cell (HSC) distribution and activation and investigated the effect of CXCL10 on HSC motility and proliferation. In order to demonstrate a possible therapeutic intervention strategy, we have examined the anti-fibrotic potential of a neutralizing anti-CXCL10 antibody. Upon CCl(4) administration, CXCL10-deficient mice showed massively reduced liver fibrosis, when compared to wildtype mice. CXCL10-deficient mice had less B- and T lymphocyte and dendritic cell infiltrations within the liver and the number and activity of HSCs was reduced. In contrast, natural killer (NK) cells were more abundant in CXCL10-deficient mice and granzyme B expression was increased in areas with high numbers of NK cells. Further detailed analysis revealed that HSCs express CXCR3, respond to CXCL10 and secrete CXCL10 when stimulated with IFNγ. Blockade of CXCL10 with a neutralizing antibody exhibited a significant anti-fibrotic effect. Our data suggest that CXCL10 is a pro-fibrotic factor, which participates in a crosstalk between hepatocytes, HSCs and immune cells. NK cells seem to play an important role in controlling HSC activity and fibrosis. CXCL10 blockade may constitute a possible therapeutic intervention for hepatic fibrosis.