CXCR3, CXCL10 and type 1 diabetes

Type 1 diabetes (T1D) is due to antigen-specific assaults on the insulin producing pancreatic β-cells by diabetogenic T-helper (Th)1 cells. (C-X-C motif) ligand (CXCL)10, an interferon-γ inducible Th1 chemokine, and its receptor, (C-X-C motif) receptor (CXCR)3, have an important role in different autoimmune diseases. High circulating CXCL10 levels were detected in new onset T1D patients, in association with a Th1 autoimmune response. Furthermore β-cells produce CXCL10, under the influence of Th1 cytokines, that suppresses their proliferation. Viral β-cells infections induce cytokines and CXCL10 expression, inducing insulin-producing cell failure in T1D. CXCL10/CXCR3 system plays a critical role in the autoimmune process and in β-cells destruction in T1D. Blocking CXCL10 in new onset diabetes seems a possible approach for T1D treatment.     

Roles of cytokines in the pathogenesis and therapy of type 1 diabetes

Type 1 diabetes (T1D) results from autoimmune destruction of the insulin-producing β-cells in the pancreatic islets of Langerhans by autoreactive T helper 1 (Th1) cells characterized by their cytokine secretory products, interleukin-2 (IL-2) and interferon γ (IFNγ). Th1-type cytokines (IL-2 and IFNγ) correlate with T1D, whereas Th2 (IL-4 and IL-10), Th3 (transforming growth factor beta [TGFβ]), and T regulatory cell-type cytokines (IL-10 and TGFβ) correlate with protection from T1D. Paradoxically, however, administrations of Th1-type cytokines (IL-2 and IFNγ) and immunotherapies that induce Th1-type cytokine responses actually prevent T1D, at least in animal models. Therefore, immunotherapies that inhibit IL-2 production/action will block Th1 cell/cytokine-driven effector mechanisms of pancreatic islet β-cell destruction; however, anti-IL-2 therapy will not allow immune tolerance to be established. In contrast, immunotherapies that increase IL-2 production/action may correct an immunodeficiency in IL-2 production that appears to underlie the autoimmunity of T1D, thereby restoring immune tolerance to islet β-cells and prevention of T1D.     

How viral infections affect the autoimmune process leading to type 1 diabetes

Despite a large body of evidence describing associations between viruses and the development of type 1 diabetes (T1D) in genetically prone individuals, clearly defining causative infectious agents has not been successful. A likely explanation is that the link between infections and autoimmunity is more multifaceted than we initially assumed. Viral footprints might be hard to detect systemically or in the target organ once autoimmunity has been initiated, and several infections might have to act in concert to precipitate clinical autoimmunity. Furthermore, cells cross-reactive between viral and self-antigens might express low avidity T cell receptors and only be present transiently in the blood of affected individuals. In addition, there are two new observations from animal models that we should take into account at this point: first, viral infections alone might not be able to induce disease in the absence of other inflammatory factors (supporting the "fertile field hypothesis" [M.G. von Herrath et al., Microorganisms and autoimmunity: making the barren field fertile? Nat. Rev. Microbiol. 1 (2003) 151-157, ]). Second, increasing evidence indicates that viruses can play a role in preventing rather than enhancing T1D development (supporting the "hygiene hypothesis" [J.F. Bach, Protective role of infections and vaccinations on autoimmune diseases. J. Autoimmun. 16 (2001) 347-353]). In this article we will present an overview of the early events and requirements that could account for T1D predisposition and development, and explain how these can be modulated by viral infections. Focusing on coxsackie B and lymphocytic choriomeningitis virus infections, we will discuss new data that can hopefully help us understand how virus-induced inflammation can positively or negatively affect the clinical outcome of islet-autoimmunity and T1D.     

Type 1 diabetes cadaveric human pancreata exhibit a unique exocrine tissue proteomic profile

Type 1 diabetes (T1D) is an autoimmune disorder resulting from a self‐destruction of pancreatic islet beta cells. The complete proteome of the human pancreas, where both the dysfunctional beta cells and their proximal environment co‐exist, remains unknown. Here, we used TMT10‐based isobaric labeling and multidimensional LC‐MS/MS to quantitatively profile the differences between pancreatic head region tissues from T1D (N = 5) and healthy subjects (N = 5). Among the 5357 (1% false discovery rate) confidently identified proteins, 145 showed statistically significant dysregulation between T1D and healthy subjects. The differentially expressed pancreatic proteome supports the growing notion of a potential role for exocrine pancreas involvement in T1D. This study also demonstrates the utility for this approach to analyze dysregulated proteins as a means to investigate islet biology, pancreatic pathology and T1D pathogenesis.     

Deficient heat shock protein 70 response to stress in leukocytes at onset of type 1 diabetes

Type 1 diabetes is caused by the immune-mediated destruction of pancreatic beta cells. Animal models of the disease demonstrate an increased susceptibility of beta cells to immunological attacks due to their defective stress-responsiveness. To investigate the stress-responsiveness in human type 1 diabetes we analyzed the heat-inducibility of the dominant stress protein heat shock protein (Hsp)70 in diabetic patients at different disease stages. At diabetes-manifestation heat-induced Hsp70 levels in peripheral blood mononuclear cells (PBMC) reached only about 25% of the levels expressed by heat-treated PBMC from non-diabetic subjects (p < 0.05). Heat-responsiveness improved with disease duration and was re-established at more than eight months after disease-manifestation. Hyperthermia-induced Hsp70 expression was decreased by the T-helper 1-associated cytokine interferon-γ and increased by the T-helper 2-associated transforming growth factor-β. We conclude that impaired cellular stress-responsiveness, aggravated by the inflammatory milieu at the onset of type 1 diabetes, contributes to disease manifestation.     

Heat shock protein 70 and albuminuria in patients with type 2 diabetes: a matched case control study

Here, we aimed to study serum heat shock protein (HSP) 70 levels in diabetic patients with and without albuminuria. We performed a 1:1 matched case control study on 40 diabetic patients with albuminuria as cases and 40 age, sex, body mass index matched diabetic patients without albuminuria (normoalbuminuria) as controls. Normoalbuminuria was defined as urinary albumin excretion rate <15 mg/12 h, and albuminuria was defined as urinary albumin excretion rate between 100–400 mg/12 h. Patients with albuminuria had a higher HSP70 than controls (0.83 ± 0.50 vs. 0.63 ± 0.06; p = 0.02), while they did not differ in any other studied variables. In ten of the studied pairs, the controls had higher HSP70 levels than cases (reverse relationship). Patients in the “direct relationship group” had higher HbA1c values than the patients in the “reverse relationship group” (8.9 ± 0.3 vs. 7.3 ± 0.6, p = 0.04). Cases in the reverse pairs had a lower low density lipoprotein cholesterol levels than their controls. The odds ratio of HSP70 in the prediction of albuminuria was (28.69 (3.2–250.1), p = 0.002). In conclusion, we have shown an increased HSP70 levels in diabetic patients with albuminuria.     

Identification and functional analysis of CBLB mutations in type 1 diabetes

Casitas B-lineage lymphoma b (Cblb) is a negative regulator of T-cell activation and dysfunction of Cblb in rats and mice results in autoimmunity. In particular, a nonsense mutation in Cblb has been identified in a rat model of autoimmune type 1 diabetes. To clarify the possible involvement of CBLB mutation in type 1 diabetes in humans, we performed mutation screening of CBLB and characterized functional properties of the mutations in Japanese subjects. Six missense mutations (A155V, F328L, N466D, K837R, T882A, and R968L) were identified in one diabetic subject each, excepting N466D. Of these mutations, F328L showed impaired suppression of T-cell activation and was a loss-of-function mutation. These data suggest that the F328L mutation is involved in the development of autoimmune diseases including type 1 diabetes, and also provide insight into the structure-function relationship of CBLB protein.     

Engineering and expression of the intracellular domain of insulinoma-associated tyrosine phosphatase (IA-2ic), a type 1 diabetes autoantigen,in plants

We have produced the recombinant intracellular domain of human IA-2 (IA-2ic), a diabetes-associated autoantigen, in plants. This was achieved by transient expression using agroinfiltration of Nicotiana benthamiana plants. The resulting plant-derived IA-2ic had the expected size, reacted with polyclonal and monoclonal antibodies specific to human IA-2ic and competitively inhibited radiolabeled IA-2ic in an immunoprecipitation assay. The expression level of recombinant IA-2ic was estimated to be 0.5% of the total soluble protein (TSP). Transient expression in plants has the potential to produce a large amount of human IA-2ic protein at low cost in a short period of time.     

Calpain10基因多态性与2 型糖尿病的相关性研究

目的：探讨钙蛋白酶10（Calpain10）基因第3内含子SNP19多态性在湖北汉族人群2型糖尿痛发生发展中的作用。方法：采用同胞对（家系内对照）和随机病例-对照两种实验设计,结合聚合酶链反应-限制性片断长度多态性（PCR-RFLP）．技术分析共403个样本的Calpain10基因第3内合子SNP19多态性,并测定身高、体重、腰围、臀围、血压和空腹血糖等生理指标。结果：两种实验设计中对照组与病例组的基因型和基因频率均无显著差异（PO．05）。结论：Calpain10基因SNP19多态性在湖北汉族人群2型糖尿病的发生发展中可能不起主要作用。     

Androgen receptor: a new player associated with apoptosis and proliferation of pancreatic beta-cell in type 1 diabetes mellitus

Androgen receptor (AR) mediates a wide range of cellular processes, such as proliferation, differentiation and apoptosis. Here we sought to identify whether AR was located in pancreatic beta-cells and investigate its functions in type 1 diabetes induced by multiple low doses of streptozotocin. Double/triple immunofluorescence, Western blot and semi-quantitative RT-PCR were carried out to determine variances of AR expression in beta-cells and correlation between AR and apoptosis/proliferation of beta-cells with progress of diabetes. In addition, in vitro primary beta-cells from control mice were cultured for 3 days or 6 days with compound stimulation in order to further identify effect of AR on beta-cell apoptosis and proliferation. AR expression in beta-cells peaked in control and 1-day diabetic mice, gradually and significantly decreased, even disappeared in diabetic mice with progress of diabetes. TUNEL-positive beta-cells were concomitant with overexpression of AR, and Ki67-positive beta-cells showed extremely weak, even negative AR staining. In vitro, AR could mediate beta-cell apoptosis, and AR antagonist flutamide contributed to beta-cell proliferation. In conclusion, AR is abundantly expressed in pancreatic beta-cell cytoplasm of control mice. With progress of type 1 diabetes, decrement of AR expression in diabetic mice contributes to prohibit beta-cells from apoptosis, and is strongly associated with beta-cell proliferation.     

Upregulation of myostatin gene expression in streptozotocin-induced type 1 diabetes mice is attenuated by insulin

Myostatin is a strong inhibitor of muscle growth, and its expression is increased in several types of muscle atrophy. However, whether or not myostatin expression is altered in muscle atrophy associated with type 1 diabetes (T1D) remains uncertain. In this study, we provided experimental evidence to show that myostatin mRNA increased in the early stage of T1D but came back to control levels later on. This expression pattern was closely correlated with the loss of body weight and atrogin-1 expression. Furthermore, induction of myostatin expression could be attenuated by insulin in T1D mice. Taken together, our findings indicate that the upregulation of myostatin expression most likely contributes to the muscle atrophy process during insulin deficiency.     

胰腺或胰岛移植后1型糖尿病复发的预测

胰腺或胰岛移植后的1型糖尿病复发(T1DR)是影响远期移植物功能的关键因素之一。由T1DR导致的移植物功能丧失约占7﹪,与慢性同种排斥反应的发生率相当。然而,由于T1DR引起的复发性高血糖缺乏特异性,导致一直以来临床上T1DR发生被严重低估。移植物组织活检提示特异性靶向β细胞的炎性T细胞浸润是诊断T1DR的“金标准”。但是,作为一种有创性操作,组织活检不作为常规筛查T1DR方法。研究显示监测移植受者的胰岛自身抗体和抗原特异性T细胞对T1DR具有预测价值。本文就胰岛自身抗体和抗原特异性T细胞对预测T1DR作一综述。     

VEGF gene variability and type 1 diabetes: evidence for a protective role

Vascular endothelial growth factor (VEGF) is a multifunctional cytokine originally described as an angiogenic factor. A number of reports have recently demonstrated that VEGF increases pancreatic islet survival after islet transplantation by stimulating angiogenesis and improving islet revascularization. Whether VEGF can protect from the autoimmune destruction of insulin-producing beta-cells that characterizes the development of type 1 diabetes is presently unknown. To clarify this issue, we studied the association of three polymorphisms of the promoter region of VEGF with type 1 diabetes in the Italian and the Finnish populations. The polymorphisms considered [C(-2578)A, G(-1190)A, and G(-1154)A] are known to modulate in vitro and in vivo VEGF expression. We found that VEGF promoter genotypes are associated with type 1 diabetes in both populations, but with different combinations. In Italian individuals, the -2578AA and -1190AA genotypes are associated with type 1 diabetes and accelerate its onset, while in Finnish individuals, -1154GG and -1190GG protect from type 1 diabetes and delay its onset. In conclusion, because the expected functional consequence of both genotype combinations is a reduced VEGF expression in diabetic patients, we propose a protective role of VEGF in the development of type 1 diabetes.     

HLA polymorphism in type 1 diabetes Tunisians

Several studies of the association between HLA and type 1 diabetes have been carried out revealing differences between ethnic groups. Our study, as part of the studies that should be performed about this association in the rest of the word, aims at elucidating the HLA DRB1, DQB1 polymorphism in Tunisian type 1 diabetes. This study includes 43 unrelated type 1 diabetes patients, and their mean age at onset is less than 15 years. Analysis of the frequency of alleles and haplotypes in these subjects, compared to a reference group (n = 101) led to the following results. 1) The Tunisian insulin-dependent diabetics present similarities as well as differences with other ethnic groups (Caucasians, North Africans). 2) The haplotype DRB1*04 DQ*0302 and DRB1*03 DQB1*0201 is positively associated to type 1 diabetes. 3) The heterozygotic genotype DRB1*04 DQB1*0302 / DRB1*03 DQB1*0201 is strongly associated to type 1 diabetes. 4) The haplotypes DRB1*01501 DQB1*0602 and DRB1*11 DQB1*0301 proved to be protective. In addition, the study of the subtypes DRB1*04 showed that alleles DRB1*0405 predispose to type 1 diabetes, whereas the allele DRB1*0403, which is in linkage disequilibrium with the DQB1*0402 in the Tunisian population, has a protective effect.     

The role of lymphotoxin signaling in the development of autoimmune pancreatitis and associated secondary extra-pancreatic pathologies

The pathogenic mechanisms of autoimmune pancreatitis (AIP), an increasingly recognized, immune-mediated form of chronic pancreatitis, have so far remained elusive. Treatment options for AIP are currently limited and disease relapse is frequent. Still, AIP can be characterized by specific clinical and histologic features. It has turned out that as described in other autoimmune diseases the generation of tertiary lymphoid organs is also a hallmark of patients with AIP. We have recently demonstrated that pancreata derived from human AIP patients display overexpression of lymphotoxin (LT) α and β and LTβR-target genes expressed by immune cells but also by irradiation resistant cells of the pancreas (e.g. acinar cells). Expression of LT α and β on acinar cells in murine pancreata Tg(Ela1-Lta,b) mice led to chronic pancreatitis and sufficed to reproduce key features of human AIP including the development of autoimmunity and AIP associated secondary extra pancreatic pathologies. Here, we review how aberrant and ectopic expression of LT α and β can induce inflammation and autoimmune diseases in general and how this knowledge might specifically lead to an alternative treatment for patients suffering from autoimmune pancreatitis.     

Double transgenic mice with type 1 diabetes mellitus develop somatic, metabolic and vascular disorders

The double transgenic mice (dTg) were obtained by mating: (i) transgenic mice expressing the hemagglutinin of influenza virus under the insulin promoter with (ii) transgenic mice expressing specific T lymphocytes with receptor for the immunodominant epitope of the same virus. In this study we show that dTg mice developed type 1 diabetes mellitus associated with hyperglycemia, low level of plasma insulin, glucosuria, weight loss and approximately 90% mortality (at 3 months biological age). The membrane of red blood cells was more sensitive to osmotic shock in diabetic mice, compared to non-diabetic mice, assessing systemic oxidative stress. Both vasoconstriction and vasorelaxation of the renal arteries decreased significantly in diabetic mice (compared to the control group of non-diabetic mice) related to the phenotypic change of endothelium and smooth muscle cells within the artery wall. This animal model, may be used in developing various strategies to study pancreatic beta-cell function, as well as for a better metabolic control conducting to a reduced risk of vascular complications.     

Mimotope-hormesis and mortalin/grp75/mthsp70: a new hypothesis on how infectious disease-associated epitope mimicry may explain low cancer burden in developing nations

It is generally observed that countries with heavy infectious burden show lower cancer incidence as compared to more affluent nations. With the emerging paradigm on microbial heat shock proteins (hsps) as molecular link between infections and autoimmune diseases, we posit a new hypothesis, the "mimotope-hormesis", on the immunologic impact of infections on regional cancer prevention. According to this, assaults of infection during early adulthood could fortify the immune system to evoke more potent defenses against late-onset diseases, such as cancer, via autoimmunity. Interestingly, both experimental and clinical data support the beneficial role of autoimmunity in long-term cancer survivors. We illustrate this by a comprehensive in silico mimotope (epitope mimicry) analysis of human infectious pathogens against mortalin (mthsp70/PB74/GRP75), a type of hsp70 protein involved in control of cell proliferation, immortalization and tumorigenesis.     

Novel AGLP-1 albumin fusion protein as a long-lasting agent for type 2 diabetes

Glucagon like peptide-1 (GLP-1) regulates glucose mediated-insulin secretion, nutrient accumulation, and β-cell growth. Despite the potential therapeutic usage for type 2 diabetes (T2D), GLP-1 has a short half-life in vivo (t_1/2 ＜2 min). In an attempt to prolong half-life, GLP-1 fusion proteins were genetically engineered: GLP-1 human serum albumin fusion (GLP-1/HSA), AGLP-1/HSA which has an additional alanine at the N-terminus of GLP-1, and AGLP-1-L/HSA, in which a peptide linker is inserted between AGLP-1 and HSA. Recombinant fusion proteins secreted from the Chinese Hamster Ovary-K1 (CHO-K1) cell line were purified with high purity (＞96%). AGLP-1 fusion protein was resistant against the dipeptidyl peptidase-IV (DPP-IV). The fusion proteins activated cAMP-mediated signaling in rat insulinoma INS-1 cells. Furthermore, a C57BL/6N mice pharmacodynamics study exhibited that AGLP-1-L/HSA effectively reduced blood glucose level compared to AGLP-1/HSA. [BMB Reports 2013; 46(12): 606-610]