Publications by authors named "Evan G Pappas"

Article Synopsis
  • - Persistent exposure to antigens leads to the development of exhausted T cells, which are less effective in responding to threats, and this phenomenon typically occurs during chronic infections and cancer, raising questions about its role in autoimmune diabetes.
  • - In a study using nonobese diabetic (NOD) mice, exhausted CD8+ T cells targeting the islet antigen IGRP were found in the pancreas, while more of these cells were preserved in peripheral lymphoid organs.
  • - By creating transgenic NOD mice that express IGRP in cells outside the islet, researchers showed that exposure to IGRP in these extraislet areas resulted in severely exhausted T cells, which ultimately protected the mice from developing diabetes.
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This Special Issue reminds us that, although incredible developments have occurred in the field of cancer immunotherapy, there is still plenty of room for improvement [...

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Article Synopsis
  • Immune checkpoint inhibitors can effectively treat cancer but are linked to immune-related side effects, including type 1 diabetes (T1D), prompting researchers to explore preventive treatments like JAK1/JAK2 inhibitors.* -
  • In experiments with nonobese diabetic mice, JAK1/JAK2 inhibitors successfully prevented and even reversed diabetes caused by PD-L1 blockade, inhibiting harmful immune cell activity in the pancreas.* -
  • The study demonstrates that JAK1/JAK2 inhibitors might be a viable option for managing diabetes resulting from cancer therapy, without compromising the anti-tumor effectiveness in other models.*
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Interferon gamma (IFNγ) is a proinflammatory cytokine implicated in autoimmune diseases. However, deficiency or neutralization of IFNγ is ineffective in reducing disease. We characterize islet antigen-specific T cells in non-obese diabetic (NOD) mice lacking all three IFN receptor genes.

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Objectives: Loss of functional β-cell mass is a key factor contributing to poor glycemic control in advanced type 2 diabetes (T2D). We have previously reported that the inhibition of the neuropeptide Y1 receptor improves the islet transplantation outcome in type 1 diabetes (T1D). The aim of this study was to identify the pathophysiological role of the neuropeptide Y (NPY) system in human T2D and further evaluate the therapeutic potential of using the Y1 receptor antagonist BIBO3304 to improve β-cell function and survival in T2D.

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T-cell responses to insulin and its precursor proinsulin are central to islet autoimmunity in humans and non-obese diabetic (NOD) mice that spontaneously develop autoimmune diabetes. Mice have two proinsulin genes proinsulin -1 and 2 that are differentially expressed, with predominant proinsulin-2 expression in the thymus and proinsulin-1 in islet beta-cells. In contrast to proinsulin-2, proinsulin-1 knockout NOD mice are protected from autoimmune diabetes.

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Aims/hypothesis: Stimulator of IFN genes (STING) is a central hub for cytosolic nucleic acid sensing and its activation results in upregulation of type I IFN production in innate immune cells. A type I IFN gene signature seen before the onset of type 1 diabetes has been suggested as a driver of disease initiation both in humans and in the NOD mouse model. A possible source of type I IFN is through activation of the STING pathway.

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Article Synopsis
  • Cytokines like IFN-γ and common γ chain cytokines play a harmful role in type 1 diabetes by promoting the destruction of insulin-producing β cells via CD8 T cells.
  • Research found that JAK1/JAK2 inhibitors can reverse autoimmune responses and reduce harmful signals in β cells related to these cytokines in non-obese diabetic mice.
  • The JAK1-selective inhibitor ABT 317 significantly reduced T cell proliferation and improved diabetes symptoms in treated mice, showing promise for future type 1 diabetes treatments.
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Aims/hypothesis: The mechanisms responsible for beta cell compensation in obesity and for beta cell failure in type 2 diabetes are poorly defined. The mRNA levels of several metallothionein (MT) genes are upregulated in islets from individuals with type 2 diabetes, but their role in beta cells is not clear. Here we examined: (1) the temporal changes of islet Mt1 and Mt2 gene expression in mouse models of beta cell compensation and failure; and (2) the role of Mt1 and Mt2 in beta cell function and glucose homeostasis in mice.

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BCL-2 proteins are known to engage each other to determine the fate of a cell after a death stimulus. However, their evolutionary conservation and the many other reported binding partners suggest an additional function not directly linked to apoptosis regulation. To identify such a function, we studied mice lacking the BH3-only protein BIM.

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Granzyme A is a protease implicated in the degradation of intracellular DNA. Nucleotide complexes are known triggers of systemic autoimmunity, but a role in organ-specific autoimmune disease has not been demonstrated. To investigate whether such a mechanism could be an endogenous trigger for autoimmunity, we examined the impact of granzyme A deficiency in the NOD mouse model of autoimmune diabetes.

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BCL-2 proteins have been implicated in the control of glucose homeostasis and metabolism in different cell types. Thus, the aim of this study was to determine the role of the pro-apoptotic BH3-only protein, p53-upregulated-modulator-of-apoptosis (PUMA), in metabolic changes mediated by diet-induced obesity, using PUMA deficient mice. At 10 weeks of age, knockout and wild type mice either continued consuming a low fat chow diet (6% fat), or were fed with a high fat diet (23% fat) for 14-17 weeks.

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Diabetes mellitus are complex, multi-organ metabolic pathologies characterized by hyperglycemia. Emerging evidence shows that the highly conserved and potent JAK/STAT signaling pathway is required for normal homeostasis, and, when dysregulated, contributes to the development of obesity and diabetes. In this review, we analyze the role of JAK/STAT activation in the brain, liver, muscle, fat and pancreas, and how this affects the course of the disease.

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Pancreatic β-cell loss induced by saturated free fatty acids (FFAs) is believed to contribute to type 2 diabetes. Previous studies have shown induction of endoplasmic reticulum (ER) stress, increased ubiquitinated proteins, and deregulation of the Bcl-2 family in the pancreas of type 2 diabetic patients. However, the precise mechanism of β-cell death remains unknown.

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