Immune modulation for prevention of type 1 diabetes mellitus

DYRK1A Inhibitors as Potential Therapeutics for β-Cell Regeneration for Diabetes

According to the World Health Organization (WHO), 422 million people are suffering from diabetes worldwide. Current diabetes therapies are focused on optimizing blood glucose control to prevent long-term diabetes complications. Unfortunately, current therapies have failed to achieve glycemic targets in the majority of people with diabetes. In this context, regeneration of functional insulin-producing human β-cells in people with diabetes through the use of DYRK1A inhibitor drugs has recently received special attention. Several small molecule DYRK1A inhibitors have been identified that induce human β-cell proliferation in vitro and in vivo. Furthermore, DYRK1A inhibitors have also been shown to synergize β-cell proliferation with other classes of drugs, such as TGFβ inhibitors and GLP-1 receptor agonists. In this perspective, we review the status of DYRK1A as a therapeutic target for β-cell proliferation and provide perspectives on technical and scientific challenges for future translational development.

Human Monocytes/Macrophage Inflammatory Cytokine Changes Following in vivo and in vitro Schistomam manoni Infection

Introduction

Epidemiological and animal studies indicate that helminth infections have positive effects due to their potential to protect against autoimmune diseases. Here, we aim to assess the effect of S. mansoni infection on immune modulation of human monocytes and their potential protection against autoimmune disease development both in vivo and in vitro.

Materials and Methods

Monocytes were isolated from helminth-infected Ethiopians (MHIE), and from Dutch healthy volunteers (MHV). The MHV were stimulated in vitro with S. mansoni soluble egg antigens (SEA) or soluble worm antigens (SWA). In addition, phenotypical changes were studied directly, as well as after culturing for 6 days in the presence of human serum to obtain macrophages. Q-PCR, flow cytometry, multiplex bead immunoassay, and live-cell imaging were employed during analysis.

Results

MHIE showed elevated transcripts of SOCS-1 and TNF-α compared to MHV. Similarly, MHV that were stimulated with SEA demonstrated enhanced levels of SOCS-1, IL-10, and IL-12 mRNA, compared to control MHV. Remarkably, the SEA-treated monocytes showed a much higher motility than control monocytes, a hallmark of a patrolling phenotype. Furthermore, in vitro cultured macrophages that were stimulated by SEA exhibited enhanced mRNA levels of SOCS-1, IL-10, TNF-α, IL-12 and TGF-β, compared to control macrophages.

Conclusion

Macrophages from MHIE as well as SEA-treated MHV show an intermediate activation phenotype with both pro-inflammatory and anti-inflammatory characteristics in vitro. The observed pro-inflammatory properties might reflect a recent response of the cells due to contact with a pathogen, whereas the anti-inflammatory properties might contribute to helminth-induced protection against inflammatory diseases. Large-scale study is recommended to consolidate the findings of the present study.

Point your SmartPhone at the code above. If you have a QR code reader the video abstract will appear. Or use:

https://youtu.be/SYOVExqwTRU

Combined use of pharmacophoric models together with drug metabolism and genotoxicity "in silico" studies in the hit finding process

In this study we propose a virtual screening strategy based on the generation of a pharmacophore hypothesis, followed by an in silico evaluation of some ADME-TOX properties with the aim to apply it to the hit finding process and, specifically, to characterize new chemical entities with potential to control inflammatory processes mediated by T lymphocytes such as multiple sclerosis, systemic lupus erithematosus or rheumatoid arthritis. As a result, three compounds with completely novel scaffolds were selected as final hits for future hit-to-lead optimization due to their anti-inflammatory profile. The biological results showed that the selected compounds increased the intracellular cAMP levels and inhibited cell proliferation in T lymphocytes. Moreover, two of these compounds were able to increase the production of IL-4, an immunoregulatory cytokine involved in the selective deviation of T helper (Th) immune response Th type 2 (Th2), which has been proved to have anti-inflammatory properties in several animal models for autoimmune pathologies as multiple sclerosis or rheumatoid arthritis. Thus our pharmacological strategy has shown to be useful to find molecules with biological activity to control immune responses involved in many inflammatory disorders. Such promising data suggested that this in silico strategy might be useful as hit finding process for future drug development.

Role of immune system modulation in prevention of type 1 diabetes mellitus

An increased incidence of Type 1 diabetes mellitus (T1DM) is expected worldwide. Eventually, T1DM is fatal unless treated with insulin. The expansion of interventions to prevent diabetes and the use of alternative treatments to insulin is a dream to be fulfilled. The pathophysiology in T1DM is basically a destruction of beta cells in the pancreas, regardless of which risk factors or causative entities have been present. Individual risk factors can have separate patho-physiological processes to, in turn, cause this beta cell destruction. Currently, autoimmunity is considered the major factor in the pathophysiology of T1DM. In a genetically susceptible individual, viral infection may stimulate the production of antibodies against a viral protein that trigger an autoimmune response against antigenically similar beta cell molecules. Many components of the immune system have been implicated in autoimmunity leading to β-cell destruction, including cytotoxic and helper T-cells, B-cells, macrophages, and dendritic cells. The inflammatory process in early diabetes is thought to be initiated and propagated by the effect of Th1-secreted cytokines (e.g. g interferon) and suppressed by Th2-secreted antiinflammatory cytokines (interleukins). Structure and function of β-cell may be modulated by using Th1/Th2-secreted cytokines. Several experimental and clinical trials of applying GAD65, Hsp60, peptide-MHC, pepetide-277 immunization, anti-CD3 infusion, and interleukins to modulate immune response in T1DM were done. Applying such trials in patients with prediabetes, will most likely be the future key in preventing Type 1 autoimmune diabetes.

GAD autoantibody epitope pattern after GAD-alum treatment in children and adolescents with type 1 diabetes

AIMS

We have previously shown that two injections of glutamic acid decarboxylase formulated in alum (GAD-alum) preserved residual insulin secretion in children and adolescents with recent onset type 1 diabetes (T1D), and was accompanied by increased GAD autoantibody (GADA) titers. The aim of this study was to investigate whether GAD-alum treatment affected the GADA epitope pattern.

METHODS

Serum samples from patients treated with GAD-alum (n = 33) or placebo (n = 27), at baseline, 1, 3, 9, and 15 months after the initial injection, were tested for their binding capacity to specific GADA epitopes in an epitope-specific radioligand binding assay with six recombinant Fab (rFab) (b96.11, DPA, DPD, MICA3, b78, and N-GAD(65) mAb).

RESULTS

No significant differences in variability of binding to any of the tested rFab were observed from baseline to 15 months. There was a sustained low binding of GADA to the b78- and N-GAD(65) mAb-defined epitopes, often recognized by GADA in patients with stiff person syndrome (SPS) and seldom in T1D patients. However, binding of GADA to the T1D-associated b96.11-defined epitope increased between baseline and 3 months in GAD-alum (-8.1%, min -72.4%, max 39.6%) compared to placebo patients (1.5%, min -28.3%, max 28.6%) (p = 0.02). Subsequently, the b96.11-defined epitope recognition returned to levels similar to that observed at baseline.

CONCLUSIONS

GAD-alum injections did not affect binding of GADA to SPS-related epitopes, further supporting the safety of the treatment. There were no changes in GADA epitope specificity to the T1D-related epitopes, except for a temporarily increased binding to one of the tested epitopes.

Oral anti-CD3 monoclonal antibody delays diabetes in non-obese diabetic (NOD) mice: effects on pregnancy and offspring--a preliminary report

BACKGROUND

The objective was to observe the effect of oral anti-CD3 monoclonal antibody (mAb) on non-obese diabetic mice, pregnancy, and offspring.

METHODS

Three protocols are classified as: (1) Twenty non-obese diabetic/ShiLtJ female mice were monitored for type 1 diabetes mellitus. If the blood glucose level was ≥ 250 mg/dL, the mice were treated for 8 days with either 50 or 100 µg oral anti-CD3 monoclonal antibody. If the diabetes resolved, the mice were bred. (2) F1 offspring were monitored for diabetes; 15 female mice became diabetic. Non-diabetic F1 female mice were divided into two groups [ten antibody (Ab) and ten control (C)] and bred. Ab female mice were given 100 µg monoclonal antibody before diabetes development and during pregnancy for 6 weeks. (3) Twenty-five F2 Ab and 23 F2 C mice were monitored. At 15-17 weeks, Ab mice, both female and male, were given 100 µg monoclonal antibody for 8 weeks.

RESULTS

(1) The diabetes in four female mice treated with 50 µg did not resolve; in three of the six diabetic female mice treated with 100 µg, the diabetes resolved and the mice were bred. The remaining ten non-diabetic female mice were given 100 µg oral monoclonal antibody and then bred. No diabetes developed during pregnancy; 13 litters were born. (2) Three diabetic Ab female mice sustained their pregnancies versus one diabetic C female mouse (p ≤ 0.05). (3) At 30 weeks, six Ab female and three Ab male mice and seven C female and three C male mice developed diabetes. The number of diabetic Ab and C mice was not different; diagnosis age was significantly different-Ab 23.3 ± 5.1 and C 18.8 ± 3.7 weeks (p ≤ 0.05).

CONCLUSIONS

In female non-obese diabetic mice, oral anti-CD3 monoclonal antibody was effective in reversing diabetes and allowing pregnancy and extending longevity, but it did not prevent diabetes in the offspring.

Immune and cell therapy in type 1 diabetes: too little too late?

INTRODUCTION

Type 1 diabetes is caused by autoimmune destruction of insulin-producing β-cells. Intensive insulin therapy protects most patients against chronic complications of diabetes, but exposes patients to acute complications like hypoglycaemia and impacts on quality of life. Therapies that aim at protecting or restoring endogenous insulin secretion might help in decreasing the risk of severe hypoglycemia and long-term complications.

AREAS COVERED

This article reviews the literature of clinical immunotherapy and β-cell transplantation in treatment of type 1 diabetes with specific focus on the effect on preserving and restoring β-cell mass.

EXPERT OPINION

Several studies in recent-onset type 1 diabetic patients have provided proof of principle that immunotherapy can preserve residual functional β-cell mass. The observation that this strategy is most effective early in the disease process opens possibilities of arresting and even preventing type 1 diabetes. In patients with too few or no surviving β-cells, current protocols of β-cell transplantation can restore functional β-cell mass up to 25% of levels in healthy controls. Unfortunately, both strategies to date are followed by progressive decline of endogenous insulin secretion later on. Strategies to restore functional β-cell mass to a higher level and to restore immune tolerance are thus needed.

Prevention of Type 1 Diabetes Mellitus using a Novel Vaccine

Type 1 diabetes mellitus (T1DM) affects 1 in 300 people and the incidence of the disease is rising worldwide. T1DM is caused by chronic autoimmune destruction of the insulin-producing β-cells. The exact etiology and primary auto-antigen are not yet known. The autoimmune, chronic, and progressive nature of the disease raises the possibility of intervention, preferably by slowing down or stopping the destruction of the β-cells as early as the prediabetic stage. Since the 1980s, several attempts have been made to maintain β-cell function using immunosuppressive agents, immune modulation such as plasmapheresis, cytokine therapy, or antibody treatment. These agents were not diabetes specific; the occasionally observed beneficial effect did not compensate for the often very severe side effects. According to the latest assumption, the administration of diabetes-specific auto-antigens can elicit tolerance, which can prevent the destruction of the β-cells, hopefully without serious side effects. The authors summarize current understanding of the immunology of T1DM, review the trials on prevention, and discuss their vaccination study.

Mathematical modelling of immune regulation of type 1 diabetes

Type 1 diabetes is a disease characterized by progressive loss of β cell function due to an autoimmune reaction affecting the islets of Langerhans. Two types of T cells are involved in diabetes: turncoat auto-reactive T cells, or T cells gone bad, that kill the insulin-producing cells, and regulatory T cells that are unable to control the auto-reactive T cells. We formulate a mathematical model that incorporates the role of cytotoxic T cells and regulatory T cells in type 1 diabetes. This study shows that onset of type 1 diabetes is due to a collective, dynamical instability, rather than being caused by a single etiological factor. It is also a numbers game between regulatory T cells and auto-reactive T cells. The problem in the onset of this disease is that there are not enough of the regulatory cells that suppress the immune response against the body's insulin-producing pancreatic islet cells.

Male and female NOD mice differentially express peroxisome proliferator-activated receptors and pathogenic cytokines

The peroxisome proliferator-activated receptors (PPARs) have been implicated in regulating the immune response. We determined the relative changes in the transcriptional expression of PPAR isoforms (α, γ1 and γ2) and cytokines involved in the pathogenesis of type 1 diabetes (T1D) in the immune cells of 5 weeks, 10 weeks and diabetic male non-obese diabetic (NOD) mice compared to those of female NOD mice from our previous studies, "normalized" against their respective non-obese diabetic resistant (NOR) mice controls. Overall PPARα was significantly more elevated in the macrophages of female NOD mice of all age groups whereas PPARγ, particularly the PPARγ2 isoform was more depressed in the macrophages and CD4(+) lymphocytes of female NOD mice compared to their male counterparts. The pro-inflammatory cytokines, IL-1 and TNFα, as well as the Th1 cytokines, IL-2 and IFNγ were more elevated in female NOD mice whereas the Th2 cytokine, IL-4, was more depressed in these mice compared to their male counterparts. These findings suggest that the preponderance of T1D in female NOD mice may be influenced by the more pronounced changes in the expression of PPAR isoforms and pathogenic cytokines compared to those in male NOD mice.

Processing and presentation of (pro)-insulin in the MHC class II pathway: the generation of antigen-based immunomodulators in the context of type 1 diabetes mellitus

Both CD4(+) and CD8(+) T lymphocytes play a crucial role in the autoimmune process leading to T1D. Dendritic cells take up foreign antigens and autoantigens; within their endocytic compartments, proteases degrade exogenous antigens for subsequent presentation to CD4(+) T cells via MHC class II molecules. A detailed understanding of autoantigen processing and the identification of autoantigenic T cell epitopes are crucial for the development of antigen-based specific immunomodulators. APL are peptide analogues of auto-immunodominant T cell epitopes that bind to MHC class II molecules and can mediate T cell activation. However, APL can be rapidly degraded by proteases occurring in the extracellular space and inside cells, substantially weakening their efficiency. By contrast, protease-resistant APL function as specific immunomodulators and can be used at low doses to examine the functional plasticity of T cells and to potentially interfere with autoimmune responses. Here, we review the latest achievements in (pro)-insulin processing in the MHC class II pathway and the generation of APL to mitigate autoreactive T cells and to activate Treg cells.

New insights into the role of VIP on the ratio of T-cell subsets during the development of autoimmune diabetes

Type I diabetes is an autoimmune T-cell-mediated disease associated with overexpression of inflammatory mediators and the disturbance of different T-cell subsets. Vasoactive intestinal peptide (VIP) is a potent anti-inflammatory agent with regulatory effects on activated T cells. As the equilibrium between different T-cell subsets is involved in the final outcome, leading to tolerance or autoimmunity, we studied the evolution of markers for T cells in nonobese diabetic (NOD) mice. The study of different transcription factors, cytokines or cytokine receptors, shows that VIP interferes with functional phase of T helper 17 (Th17) cells and prevents the increase in the proportion of Th1 to Th17 cells. On the other hand, VIP-treated NOD mice show an increase in the proportion of CD4(+)CD25(+) cells in the spleen. Thus, VIP switches the Tregs/Th17 ratio leading to tolerance in NOD mice. Similarly, VIP reverses the ratio of Th1-/Th2-cell subsets associated with autoimmune pathology. All these effects on the ratio of T-cell subsets and the anti-inflammatory effect of VIP in decreasing proinflammatory mediators result in a reduction of β-cell destruction in pancreas. Taken together, these results show that VIP provides significant protection against spontaneous diabetes by modulating T-cell subsets and counterbalancing tolerance and immunity.

Scorpion venom and the inflammatory response

Scorpion venoms consist of a complex of several toxins that exhibit a wide range of biological properties and actions, as well as chemical compositions, toxicity, and pharmacokinetic and pharmacodynamic characteristics. These venoms are associated with high morbility and mortality, especially among children. Victims of envenoming by a scorpion suffer a variety of pathologies, involving mainly both sympathetic and parasympathetic stimulation as well as central manifestations such as irritability, hyperthermia, vomiting, profuse salivation, tremor, and convulsion. The clinical signs and symptoms observed in humans and experimental animals are related with an excessive systemic host inflammatory response to stings and stings, respectively. Although the pathophysiology of envenomation is complex and not yet fully understood, venom and immune responses are known to trigger the release of inflammatory mediators that are largely mediated by cytokines. In models of severe systemic inflammation produced by injection of high doses of venom or venoms products, the increase in production of proinflammatory cytokines significantly contributes to immunological imbalance, multiple organ dysfunction and death. The cytokines initiate a cascade of events that lead to illness behaviors such as fever, anorexia, and also physiological events in the host such as activation of vasodilatation, hypotension, and increased of vessel permeability.

Regulation of type 1 diabetes, tuberculosis, and asthma by parasites

Helminth infection is a worldwide health problem. In addition to directly causing disease, helminthic infection also affects the incidence and progression of other diseases by exerting immune modulatory effects. In animal models, infection with helminthic parasites can prevent autoimmune diseases and allergic inflammatory diseases, but worsens protective immunity to certain infectious pathogens. In this review, we summarize current findings regarding the effects of helminth infection on type 1 diabetes, tuberculosis, and asthma and discuss possible mechanisms through which helminthic parasites modulate host immunity. Investigating these mechanisms could lead to treatment strategies that specifically modulate the immune response as well as address fundamental questions in immunobiology.

Protease-resistant human GAD-derived altered peptide ligands decrease TNF-alpha and IL-17 production in peripheral blood cells from patients with type 1 diabetes mellitus

Glutamic acid decarboxylase 65 (GAD) and proinsulin are major diabetes-associated autoantigens that drive autoreactive T cells. Altered peptide ligands (APL) have been proposed as reagents for the modification of autoimmune reactions. Here, we have prepared GAD-derived protease-resistant APL (prAPL) by cleavage site-directed modification. The resulting prAPL are resistant to lysosomal and serum proteases, bind with high-affinity to HLA-DRB1(*)0401 and have a prolonged half-life in the serum. GAD-derived prAPL significantly decreased the secretion of proinflammatory cytokines by a GAD-specific human T cell clone. Likewise, the production of IL-17, TNF-alpha, and secretion of IL-6 by peripheral blood lymphocytes from patients with type 1 diabetes mellitus (T1D) was reduced, when stimulated with both GAD and GAD-derived prAPL. Thus, prAPL with high affinity for HLA-DRB1(*)0401 mitigate the response of GAD-reactive human Th17 cells. The strategy of designing specific immunomodulatory protease-resistant altered peptide ligands provides the basis for novel avenues of therapeutic intervention.

Anti-inflammatory cytokine gene therapy decreases sensory and motor dysfunction in experimental Multiple Sclerosis: MOG-EAE behavioral and anatomical symptom treatment with cytokine gene therapy

Multiple Sclerosis (MS) is an autoimmune inflammatory disease that presents clinically with a range of symptoms including motor, sensory, and cognitive dysfunction as well as demyelination and lesion formation in brain and spinal cord. A variety of animal models of MS have been developed that share many of the pathological hallmarks of MS including motor deficits (ascending paralysis), demyelination and axonal damage of central nervous system (CNS) tissue. In recent years, neuropathic pain has been recognized as a prevalent symptom of MS in a majority of patients. To date, there have been very few investigations into sensory disturbances in animal models of MS. The current work contains the first assessment of hind paw mechanical allodynia (von Frey test) over the course of a relapsing-remitting myelin oligodendrocyte glycoprotein induced experimental autoimmune encephalomyelitis (MOG-EAE) rat model of MS and establishes the utility of this model in examining autoimmune induced sensory dysfunction. We demonstrate periods of both decreased responsiveness to touch that precedes the onset of hind limb paralysis, and increased responsiveness (allodynia) that occurs during the period of motor deficit amelioration traditionally referred to as symptom remission. Furthermore, we tested the ability of our recently characterized anti-inflammatory IL-10 gene therapy to treat the autoimmune inflammation induced behavioral symptoms and tissue histopathological changes. This therapy is shown here to reverse inflammation induced paralysis, to reduce disease associated reduction in sensitivity to touch, to prevent the onset of allodynia, to reverse disease associated loss of body weight, and to suppress CNS glial activation associated with disease progression in this model.

T cell cytokine gene polymorphisms in canine diabetes mellitus

Insulin-deficiency diabetes in dogs shares some similarities with human latent autoimmune diabetes of adults (LADA). Canine diabetes is likely to have a complex pathogenesis with multiple genes contributing to overall susceptibility and/or disease progression. An association has previously been shown between canine diabetes and MHC class II genes, although other genes are also likely to contribute to the genetic risk. Potential diabetes susceptibility genes include immuno-regulatory TH1/TH2 cytokines such as IFNgamma, IL-12, IL-4 and IL-10. We screened these candidate genes for single nucleotide polymorphisms (SNPs) in a range of different dog breeds using dHPLC analysis and DNA sequencing. Thirty-eight of the SNPs were genotyped in crossbreed dogs and seven other breed groups (Labrador Retriever, West Highland White Terrier, Collie, Schnauzer, Cairn Terrier, Samoyed and Cavalier King Charles Spaniel), which demonstrated substantial intra-breed differences in allele frequencies. When SNPs were examined for an association with diabetes by case:control analysis significant associations were observed for IL-4 in three breeds, the Collie, Cairn Terrier and Schnauzer and for IL-10 in the Cavalier King Charles Spaniel. These results suggest that canine cytokine genes regulating the TH1/TH2 immune balance might play a contributory role in determining susceptibility to diabetes in some breeds.

AAV8-mediated gene transfer of interleukin-4 to endogenous beta-cells prevents the onset of diabetes in NOD mice

We have demonstrated the ability to deliver and express genes specifically in beta-cells for at least 6 months, using a murine insulin promoter (mIP) in a double-stranded, self-complementary AAV vector (dsAAV8-mIP). In this study, we evaluated the effects of dsAAV8-mIP-mediated delivery of interleukin 4 (mIL-4) to endogenous beta-cells in nonobese diabetic (NOD) mice. In 4-week-old NOD mice, the extent of gene transfer and expression in endogenous beta-cells after ip delivery of dsAAV8-mIP-enhanced green fluorescent protein (eGFP) was comparable to normal BALB/C mice. Further, after IP delivery of dsAAV8-mIP-IL4, expression of mIL-4 was detected in islets isolated from the treated mice and cultured. AAV8-mIP-mediated gene expression of mIL-4 in endogenous beta- cells of 4- and 8-week-old NOD mice prevented the onset of hyperglycemia in NOD mice and reduced the severity of insulitis. Moreover, expression of mIL-4 also maintained the level of CD4(+)CD25(+)FoxP3(+) cells, and adoptive transfer of splenocytes from nondiabetic dsAAV8-mIP-IL-4 mice to NODscid mice was able to block the diabetes induced by splenocytes co-adoptively transferred from nondiabetic dsAAV-mIP-eGFP mice. Taken together, these results demonstrate that local expression of mIL-4 in islets prevents islet destruction and blocks autoimmunity, partly through regulation of T-cell function.

Analysis of Candidate Susceptibility Genes in Canine Diabetes

Canine diabetes is a complex genetic disease of unknown aetiology. It affects 0.005-1.5% of the canine population and shows a clear breed predisposition with the Samoyed being at high risk and the Boxer being at low risk of developing the disease. Canine diabetes is considered to be a disease homologue for human type 1 diabetes (T1D). It results in insulin deficiency as a consequence of autoimmune destruction of islet beta-cells in the pancreas and is believed to be mediated by Th1 cytokines (IFNgamma, TNFalpha, and IL-2). A number of genes have been associated with type 1 diabetes in humans, including the human leukocyte antigen region, the insulin variable number tandem repeat, PTPN22, CTLA4, IL-4, and IL-13. As yet, these genes have not been evaluated in canine diabetes. In this study, 483 cases of canine diabetes and 869 controls of known breed were analyzed for association with IFNgamma, IGF2, IL-10, IL-12beta, IL-6, insulin, PTPN22, RANTES, IL-4, IL-1alpha and TNFalpha. Minor allele frequencies were determined for these genes in each breed. These data were used for comparative analyses in a case-control study, and clear associations with diabetes were identified in some breeds with certain alleles of candidate genes. Some associations were with increased susceptibility to the disease (IFNgamma, IL-10, IL-12beta, IL-6, insulin, PTPN22, IL-4, and TNFalpha), whereas others were protective (IL-4, PTPN22, IL-6, insulin, IGF2, TNFalpha). This study demonstrates that a number of the candidate genes previously associated with human T1D also appear to be associated with canine diabetes and identifies an IL-10 haplotype which is associated with diabetes in the Cavalier King Charles Spaniel. This suggests that canine diabetes is an excellent comparative and spontaneously occurring disease model of human T1D.

Effects of diazoxide on gene expression in rat pancreatic islets are largely linked to elevated glucose and potentially serve to enhance beta-cell sensitivity

Diazoxide enhances glucose-induced insulin secretion from beta-cells through mechanisms that are not fully elucidated. Here, we used microarray analysis (Affymetrix) to investigate effects of diazoxide. Pancreatic islets were cultured overnight at 27, 11, or 5.5 mmol/l glucose with or without diazoxide. Inclusion of diazoxide upregulated altogether 211 genes (signal log(2) ratio > or =0.5) and downregulated 200 genes (signal log(2) ratio -0.5 or lower), and 92% of diazoxide's effects (up- and downregulation) were observed only after coculture with 11 or 27 mmol/l glucose. We found that 11 mmol/l diazoxide upregulated 97 genes and downregulated 21 genes. Increasing the glucose concentration to 27 mmol/l markedly shifted these proportions toward downregulation (101 genes upregulated and 160 genes downregulated). At 27 mmol/l glucose, most genes downregulated by diazoxide were oppositely affected by glucose (80%). Diazoxide influenced expression of several genes central to beta-cell metabolism. Diazoxide downregulated genes of fatty acid oxidation, upregulated genes of fatty acid synthesis, and downregulated uncoupling protein 2 and lactic acid dehydrogenase. Diazoxide upregulated certain genes known to support beta-cell functionality, such as NKX6.1 and PDX1. Long-term elevated glucose is permissive for most of diazoxide's effects on gene expression, the proportion of effects shifting to downregulation with increasing glucose concentration. Effects of diazoxide on gene expression could serve to enhance beta-cell functionality during continuous hyperglycemia.

Immune tolerance induced by adoptive transfer of dendritic cells in an insulin-dependent diabetes mellitus murine model

AIM

To investigate the effect and underlying mechanisms of immune-tolerance induced by the adoptive transfer of bone marrow (BM)-derived dendritic cells (DC) in insulin-dependent diabetes mellitus (IDDM) mice.

METHODS

The IDDM model was established by a low dose of streptozotocin (STZ) in Balb/c mice. Two DC subpopulations were generated from the BM cells with granulocyte-macrophage colony-stimulating factor with or without interleukin-4. The purity and the T cell stimulatory capability of DC were identified. These cells were used to modulate autoimmune response in pre-diabetic mice. Blood glucose was examined weekly; pancreas tissues were taken for histopathological analysis, and CD4(+) T cells were isolated to detect lymphocyte proliferation by MTT assay and the ratio of CD4(+)CD25(+) T cells by fluorescence-activated cell sorting (FACS). The cytokine secretion was determined by ELISA analysis.

RESULTS

Two DC subsets were generated from BM, which have phenotypes of mature DC (mDC) and immature DC (iDC), respectively. The level of blood glucose decreased significantly by transferring iDC (P< 0.01) rather than mDC. Less lymphocyte infiltration was observed in the islets, and pancreatic structure was intact. In vitro, proliferation of lymphocytes decreased and the proportion of CD4(+)CD25(+) T cells increased remarkably, compared with the mDC-treated groups (P< 0.05), which were associated with increased level of the Th2 cytokine and reduced level of the Th1 cytokine after iDC transfer.

CONCLUSION

Our data showed that iDC transfer was able to confer protection to mice from STZ-induced IDDM. The immune-tolerance to IDDM may be associated with promoting the production of CD4(+)CD25(+) T cells and inducing regulatory Th2 responses in vivo.

Experience with experimental biological treatment and local gene therapy in Sjogren's syndrome: implications for exocrine pathogenesis and treatment

Sjögren's syndrome is an autoimmune exocrinopathy, mainly affecting the lacrimal and salivary glands, and resulting in ocular and oral dryness (keratoconjunctivitis sicca and xerostomia). The aetiology and pathogenesis are largely unknown, and only palliative treatment is currently available. Data obtained from experimental animal and human studies using biological agents or gene therapeutics can offer insight into the disease process of Sjögren's syndrome. This article reviews the current literature on these approaches and assesses the lessons learnt about the pathogenesis of Sjögren's syndrome.

NOD mouse model for Sjögren's syndrome: lack of longitudinal stability

OBJECTIVES

The non-obese diabetic (NOD) mouse is not only a widely used model for diabetes mellitus type I, but also for the chronic autoimmune disease Sjögren's syndrome (SS), mainly affecting salivary and lacrimal glands. We studied the efficacy of local recombinant serotype 2 adeno-associated viral (rAAV2) vector transfer of immunomodulatory transgenes to alter the SS-like disease in NOD mice. Data collected over a 2-year period indicated a changing SS phenotype in these mice and this phenomenon was investigated.

METHODS

10(10) particles rAAV2LacZ/gland were delivered to both submandibular glands (SMGs) of NOD/LtJ mice at 8 weeks (before sialadenitis onset) of age. Salivary flow rates were determined at 8 weeks and time of killing. Blood glucose levels and body weights were measured weekly. After killing, saliva and SMGs were harvested. Analyses of salivary output, inflammatory infiltrates (focus score), SMG cytokine profile, body weight, and diabetes mellitus status were performed. Data from six different experimental studies over 2 years were analyzed and compared.

RESULTS

Salivary flow rate, focus score, and SMG cytokines interleukin (IL)-2, IL-4, IL-6, IL-10, IL-12(p70), tumor necrosis factor-alpha and IFNgamma showed changes over time. There were no differences for body weight, diabetes mellitus prevalence, or blood glucose level of non-diabetic mice.

CONCLUSION

This retrospective report is the first to describe longitudinal variability in the NOD mouse as a model for SS. We advise other investigators to continuously monitor the SS phenotype parameters and include appropriate controls when studying this disease in NOD mice.

Pro-apoptotic DNA vaccination ameliorates new onset of autoimmune diabetes in NOD mice and induces foxp3+ regulatory T cells in vitro

We have shown previously that incorporation of a cDNA coding for the pro-apoptotic protein BAX into plasmid DNA coding for a secreted form of the pancreatic beta-cell antigen glutamic acid decarboxylase (GAD) promotes prevention of type 1 diabetes in non-obese diabetic (NOD) mice. Here we present evidence indicating that injection of the same vaccine at time of early diabetes onset could ameliorate the disease with efficacy, with 42% of mice overtly diabetic by 40 weeks of age compared to 92% in control groups. In addition, immunological analysis revealed that the DNA vaccine induced CD4(+)CD25(+) T cells cultured from draining lymph nodes that had immunosuppressive function in vitro. The induced regulatory T cells (Tregs) expressed the foxp3 gene and showed cell-contact-dependent as well as TGF-beta- and IL-10-independent immunosuppressive activity. Data also revealed that CD4(+)CD25(-) T cells from mice immunized with the DNA vaccine yielded a cell population that was foxp3(+), showed increased expression of CD25 compared to control, and had immunosuppressive function in vitro, indicating that Tregs could have developed from antigen-induced, peripheral T lymphocytes. In contrast, injection of DNA coding for SGAD55 or BAX alone did not induce Tregs. Altogether, our data confirm that pro-apoptotic DNA vaccination can be used as an immunosuppressive strategy and demonstrate its potential for therapy of pathological autoimmunity.

An early but intense cytokine production within the islets may be predictive for type 1 diabetes occurrence in the Bio Breeding (BB) rat

The Bio Breeding (BB) rat is a useful animal model of type 1 autoimmune diabetes. The aim of this study was to observe and follow the cytokine and antigenic expressions within the islets of Langerhans in young non-diabetic, in pre-diabetic hyperglycemic, and in overtly diabetic animals. BB rats were therefore checked at day 21 up to day 90 of life for blood glucose, insulin levels, degree of islet infiltration, expression of proinflammatory and protective cytokines and antibodies including CD4, CD8, CD25, LFA-1, and ICAM-1. Animals were treated with insulin as they became diabetic. We found that islets of non-diabetic BB rats became positive to both IL-1beta and IL-4 very early on, confirming a local but intense production of both cytokines within the islets during the initial non-diabetic period. In addition, we observed that the production of these interleukins together with the expression levels of CD4 and CD25 are events predictive for type 1 diabetes onset in non-diabetic BB rats, as for non-obese diabetic (NOD) mice. In particular, the production of IL-1beta and IL-4 during the non-diabetic period together with the lack of enhancement of CD4 and CD25, indicating selective recruitment of activated T cells, may explain the failure of anti-diabetic treatments in this animal model of type 1 diabetes.

PROTECTING THE PUMP: Controlling Myocardial Inflammatory Responses

Because of the anatomy, function, and nonregenerative nature of the myocardium, inflammation in this tissue is not well tolerated. Nevertheless, various diseases of the heart are characterized by inflammatory responses involving the effector mechanisms of innate and adaptive (lymphocyte-dependent) immunity. The innate immune response to ischemia-reperfusion injury is, by far, the most common cause of myocardial inflammation. Innate responses may have beneficial influences that preserve myocardial function in the short term but may be maladaptive in chronic states. Adaptive responses in the myocardium occur with infection or loss of tolerance, and lead to myocarditis. Given the narrow margin for benefit of cardiac inflammation, special regulatory mechanisms likely raise the threshold, compared to other tissues, for the induction and persistence of adaptive immune responses. These mechanisms include strong central and peripheral T cell tolerance to heart antigens and induction of anti-inflammatory feedback mechanisms involving cytokines such as interferon-gamma.

Heat shock proteins in autoimmune diseases

Heat shock proteins (hsp's) are among the most conserved proteins in evolution. They have been identified as important pathogen-related antigens as well as autoantigens suitable for construction of novel vaccines. The high evolutionary homology of hsp's has raised the question about the safety of such vaccines. Experimental and clinical observations have confirmed that hsp proteins are involved in the regulation of some autoimmune disease such as autoimmune arthritis, type 1 diabetes mellitus, atherosclerosis, multiple sclerosis, and other autoimmune reactions. It has been shown in experimental animals that some hsp proteins (especially hsp60, hsp70, and hsp10) can either induce or prevent autoimmune reactions depending on the circumstances. This article discusses the involvement of hsp proteins in the etiology of autoimmune diseases and it presents promising experimental data on the effects of immunization with hsp proteins in the prevention and therapy of autoimmune diseases.

Immunomodulation with human recombinant autoantigens

The loss of beta cells in type 1 diabetes is the consequence of a T cell-dependent autoimmune attack. Autoantibodies against GAD65 (Mr 65.000 isoform of glutamic acid decarboxylase), IA-2 (insulinoma-associated protein IA-2) or insulin, alone or in combination, predict disease. Preclinical studies in spontaneously diabetic rodents suggest that immunomodulation with autoantigens might alter the course of autoimmune diabetes. Oral insulin reduces the development of diabetes in risk subjects with high insulin autoantibody levels. Giving alum-formulated GAD65 to patients classified with latent autoimmune diabetes of the adult (LADA) is safe and suggests possible immunomodulating effects of GAD65. Future immunomodulation trials might better ascertain subjects based on HLA genetic risk factors, the level of insulin that is still produced or by combining autoantigens with, for example, anti-CD3 antibodies, to induce antigen-specific tolerance and thereby a long-lasting protection for beta cells.