scholarly journals Effect of Coxsackievirus B4 Infection on the Thymus: Elucidating Its Role in the Pathogenesis of Type 1 Diabetes

2021 ◽  
Vol 9 (6) ◽  
pp. 1177
Author(s):  
Abdulaziz Alhazmi ◽  
Magloire Pandoua Nekoua ◽  
Hélène Michaux ◽  
Famara Sane ◽  
Aymen Halouani ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
T Cell ◽  
Viral Infections ◽  
Lymphoid Organ ◽  
Thymic Epithelial Cells ◽  
Central Tolerance ◽  
Coxsackievirus B4

The thymus gland is a primary lymphoid organ for T-cell development. Various viral infections can result in disturbance of thymic functions. Medullary thymic epithelial cells (mTECs) are important for the negative selection of self-reactive T-cells to ensure central tolerance. Insulin-like growth factor 2 (IGF2) is the dominant self-peptide of the insulin family expressed in mTECs and plays a crucial role in the intra-thymic programing of central tolerance to insulin-secreting islet β-cells. Coxsackievirus B4 (CVB4) can infect and persist in the thymus of humans and mice, thus hampering the T-cell maturation and differentiation process. The modulation of IGF2 expression and protein synthesis during a CVB4 infection has been observed in vitro and in vivo in mouse models. The effect of CVB4 infections on human and mouse fetal thymus has been studied in vitro. Moreover, following the inoculation of CVB4 in pregnant mice, the thymic function in the fetus and offspring was disturbed. A defect in the intra-thymic expression of self-peptides by mTECs may be triggered by CVB4. The effects of viral infections, especially CVB4 infection, on thymic cells and functions and their possible role in the pathogenesis of type 1 diabetes (T1D) are presented.

scholarly journals Mechanisms of Igf2 inhibition in thymic epithelial cells infected by coxsackievirus CV-B4

2020 ◽  
Author(s):  
Hélène Michaux ◽  
Aymen Halouani ◽  
Charlotte Trussart ◽  
Chantal Renard ◽  
Hela Jaïdane ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Epithelial Cells ◽  
Thymic Epithelial Cells ◽  
Thymic Epithelial Cell ◽  
Epithelial Cell Line ◽  
Central Tolerance ◽  
Coxsackievirus B4 ◽  
Stat3 Signaling

ABSTRACTEpidemiological studies have evidenced a link between type 1 diabetes (T1D) and infections by enteroviruses, especially with coxsackievirus B4 (CV-B4). CV-B4 is able to infect human and murine thymic epithelial cells (TECs) and, in a murine TEC line, we have shown that the diabetogenic strain CV-B4 E2 decreases transcription of insulin-like growth factor 2 gene (Igf2), coding for the self-peptide of the insulin family. Here we show that in CV-B4 infection of mice alters Igf2 transcripts isoforms in TECs, followed by a decrease of pro-IGF2 precursor in the thymus. CV-B4 infection of a murine TEC line decreases Igf2 P3 promoter activity by targeting the region −68 to −22 upstream of the transcription start site (TSS) whereas Igf2 transcripts stability is not affected, pointing towards a regulation of Igf2 transcription. Our data also show that CV-B4 decreases IL-6/STAT3 signaling in vitro. This study provides new knowledge about the regulation of intrathymic Igf2 transcription by CV-B4 and reinforces the hypothesis that CV-B4 infection of the thymus could break central self-tolerance of the insulin family by decreasing Igf2 transcription and IGF2 presentation in thymus epithelium.IMPORTANCECoxsackievirus B4 represents one of the most important environmental factors associated to type 1 diabetes, autoimmune disease for which no curative treatment exist. The diabetogenic strain Coxsackievirus B4 E2 was previously shown to decrease Igf2 expression, important player for central tolerance towards insulin, in a thymic epithelial cell line. The understanding of Igf2 regulation mechanisms during coxsackievirus B4 infection represents an interest for the understanding of central tolerance development but also for Igf2 transcriptional regulation itself, still poorly understood.Here we demonstrate that, some transcripts isoforms of Igf2 are also decreased in thymic epithelial cells in vivo. Moreover, we show that this decrease is induced by an alteration of specific regions of Igf2 P3 promoter and may be linked by a decrease of STAT3 signaling. In fine we hope that this work could lead to future therapies leading to reprogramming central tolerance towards β cells antigens via Igf2 expression.

scholarly journals NKG2D signaling within the pancreatic islets reduces NOD diabetes and increases protective central memory CD8+ T cell numbers

2020 ◽  
Author(s):  
Ada Admin ◽  
Andrew P. Trembath ◽  
Kelsey L. Krausz ◽  
Neekun Sharma ◽  
Ivan C. Gerling ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
Autoimmune Diabetes ◽  
Central Memory ◽  
Anatomical Location

NKG2D is implicated in autoimmune diabetes. However, the role of this receptor in diabetes pathogenesis is unclear owing to conflicting results with studies involving global inhibition of NKG2D signaling. We found that NKG2D and its ligands are present in human pancreata, with expression of NKG2D and its ligands increased in the islets of patients with type 1 diabetes. To directly assess the role of NKG2D in the pancreas, we generated NOD mice that express an NKG2D ligand in b-islet cells. Diabetes was reduced in these mice. The reduction corresponded with a decrease in the effector to central memory CD8<sup>+</sup> T cell ratio. Further, NKG2D signaling during in vitro activation of both mouse and human CD8+ T cells resulted in an increased number of central memory CD8<sup>+</sup> T cells and diabetes protection by central memory CD8<sup>+</sup> T cells in vivo. Taken together, these studies demonstrate that there is a protective role for central memory CD8<sup>+</sup> T cells in autoimmune diabetes and that this protection is enhanced with NKG2D signaling. These findings stress the importance of anatomical location when determining the role NKG2D signaling plays, as well as when developing therapeutic strategies targeting this pathway, in type 1 diabetes development.

scholarly journals A miRNA181a/NFAT5 axis links impaired T cell tolerance induction with autoimmune type 1 diabetes

2018 ◽  
Vol 10 (422) ◽  
pp. eaag1782 ◽  
Author(s):  
Isabelle Serr ◽  
Martin G. Scherm ◽  
Adam M. Zahm ◽  
Jonathan Schug ◽  
Victoria K. Flynn ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
Early Stage ◽  
Tolerance Induction ◽  
Islet Autoimmunity ◽  
Activated T Cells

Molecular checkpoints that trigger the onset of islet autoimmunity or progression to human type 1 diabetes (T1D) are incompletely understood. Using T cells from children at an early stage of islet autoimmunity without clinical T1D, we find that a microRNA181a (miRNA181a)–mediated increase in signal strength of stimulation and costimulation links nuclear factor of activated T cells 5 (NFAT5) with impaired tolerance induction and autoimmune activation. We show that enhancing miRNA181a activity increases NFAT5 expression while inhibiting FOXP3+ regulatory T cell (Treg) induction in vitro. Accordingly, Treg induction is improved using T cells from NFAT5 knockout (NFAT5ko) animals, whereas altering miRNA181a activity does not affect Treg induction in NFAT5ko T cells. Moreover, high costimulatory signals result in phosphoinositide 3-kinase (PI3K)–mediated NFAT5, which interferes with FoxP3+ Treg induction. Blocking miRNA181a or NFAT5 increases Treg induction in murine and humanized models and reduces murine islet autoimmunity in vivo. These findings suggest targeting miRNA181a and/or NFAT5 signaling for the development of innovative personalized medicines to limit islet autoimmunity.

scholarly journals NKG2D signaling within the pancreatic islets reduces NOD diabetes and increases protective central memory CD8+ T cell numbers

2020 ◽  
Author(s):  
Ada Admin ◽  
Andrew P. Trembath ◽  
Kelsey L. Krausz ◽  
Neekun Sharma ◽  
Ivan C. Gerling ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
Autoimmune Diabetes ◽  
Central Memory ◽  
Anatomical Location

NKG2D is implicated in autoimmune diabetes. However, the role of this receptor in diabetes pathogenesis is unclear owing to conflicting results with studies involving global inhibition of NKG2D signaling. We found that NKG2D and its ligands are present in human pancreata, with expression of NKG2D and its ligands increased in the islets of patients with type 1 diabetes. To directly assess the role of NKG2D in the pancreas, we generated NOD mice that express an NKG2D ligand in b-islet cells. Diabetes was reduced in these mice. The reduction corresponded with a decrease in the effector to central memory CD8<sup>+</sup> T cell ratio. Further, NKG2D signaling during in vitro activation of both mouse and human CD8+ T cells resulted in an increased number of central memory CD8<sup>+</sup> T cells and diabetes protection by central memory CD8<sup>+</sup> T cells in vivo. Taken together, these studies demonstrate that there is a protective role for central memory CD8<sup>+</sup> T cells in autoimmune diabetes and that this protection is enhanced with NKG2D signaling. These findings stress the importance of anatomical location when determining the role NKG2D signaling plays, as well as when developing therapeutic strategies targeting this pathway, in type 1 diabetes development.

scholarly journals Modeling Type 1 Diabetes Using Pluripotent Stem Cell Technology

2021 ◽  
Vol 12 ◽  
Author(s):  
Kriti Joshi ◽  
Fergus Cameron ◽  
Swasti Tiwari ◽  
Stuart I. Mannering ◽  
Andrew G. Elefanty ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Stem Cell ◽  
Genetic Variants ◽  
Genetic Background ◽  
Pluripotent Stem Cell ◽  
Cell Types ◽  
Polygenic Inheritance

Induced pluripotent stem cell (iPSC) technology is increasingly being used to create in vitro models of monogenic human disorders. This is possible because, by and large, the phenotypic consequences of such genetic variants are often confined to a specific and known cell type, and the genetic variants themselves can be clearly identified and controlled for using a standardized genetic background. In contrast, complex conditions such as autoimmune Type 1 diabetes (T1D) have a polygenic inheritance and are subject to diverse environmental influences. Moreover, the potential cell types thought to contribute to disease progression are many and varied. Furthermore, as HLA matching is critical for cell-cell interactions in disease pathogenesis, any model that seeks to test the involvement of particular cell types must take this restriction into account. As such, creation of an in vitro model of T1D will require a system that is cognizant of genetic background and enables the interaction of cells representing multiple lineages to be examined in the context of the relevant environmental disease triggers. In addition, as many of the lineages critical to the development of T1D cannot be easily generated from iPSCs, such models will likely require combinations of cell types derived from in vitro and in vivo sources. In this review we imagine what an ideal in vitro model of T1D might look like and discuss how the required elements could be feasibly assembled using existing technologies. We also examine recent advances towards this goal and discuss potential uses of this technology in contributing to our understanding of the mechanisms underlying this autoimmune condition.

scholarly journals Glycosylation of CaV3.2 Channels Contributes to the Hyperalgesia in Peripheral Neuropathy of Type 1 Diabetes

2020 ◽  
Vol 14 ◽  
Author(s):  
Sonja Lj. Joksimovic ◽  
J. Grayson Evans ◽  
William E. McIntire ◽  
Peihan Orestes ◽  
Paula Q. Barrett ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Adult Female ◽  
Molecular Mechanisms ◽  
Sprague Dawley ◽  
Knock Out ◽  
Peripheral Diabetic Neuropathy ◽  
Novel Treatments

Our previous studies implicated glycosylation of the CaV3.2 isoform of T-type Ca2+ channels (T-channels) in the development of Type 2 painful peripheral diabetic neuropathy (PDN). Here we investigated biophysical mechanisms underlying the modulation of recombinant CaV3.2 channel by de-glycosylation enzymes such as neuraminidase (NEU) and PNGase-F (PNG), as well as their behavioral and biochemical effects in painful PDN Type 1. In our in vitro study we used whole-cell recordings of current-voltage relationships to confirm that CaV3.2 current densities were decreased ~2-fold after de-glycosylation. Furthermore, de-glycosylation induced a significant depolarizing shift in the steady-state relationships for activation and inactivation while producing little effects on the kinetics of current deactivation and recovery from inactivation. PDN was induced in vivo by injections of streptozotocin (STZ) in adult female C57Bl/6j wild type (WT) mice, adult female Sprague Dawley rats and CaV3.2 knock-out (KO mice). Either NEU or vehicle (saline) were locally injected into the right hind paws or intrathecally. We found that injections of NEU, but not vehicle, completely reversed thermal and mechanical hyperalgesia in diabetic WT rats and mice. In contrast, NEU did not alter baseline thermal and mechanical sensitivity in the CaV3.2 KO mice which also failed to develop painful PDN. Finally, we used biochemical methods with gel-shift analysis to directly demonstrate that N-terminal fragments of native CaV3.2 channels in the dorsal root ganglia (DRG) are glycosylated in both healthy and diabetic animals. Our results demonstrate that in sensory neurons glycosylation-induced alterations in CaV3.2 channels in vivo directly enhance diabetic hyperalgesia, and that glycosylation inhibitors can be used to ameliorate painful symptoms in Type 1 diabetes. We expect that our studies may lead to a better understanding of the molecular mechanisms underlying painful PDN in an effort to facilitate the discovery of novel treatments for this intractable disease.

Experimental silicosis: a shift to a preferential IFN-γ-based Th1 response in thoracic lymph nodes

2000 ◽  
Vol 278 (6) ◽  
pp. L1221-L1230 ◽  
Author(s):  
Holger Garn ◽  
Anke Friedetzky ◽  
Andrea Kirchner ◽  
Ruth Jäger ◽  
Diethard Gemsa
Keyword(s):  
T Cell ◽  
Lymph Nodes ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cytotoxic T Cell ◽  
Mrna Levels ◽  
Ifn Γ

In chronic silicosis, mechanisms leading to lymphocyte activation are still poorly understood, although it is well known that not only the lung but also the draining lymph nodes are affected. In the present study, we investigated T-cell activation by analysis of cytokine expression in the enlarged thoracic lymph nodes of rats 2 mo after an 8-day silica aerosol exposure. In the case of helper T cell (Th) type 1 cytokines, we found a significant increase in interferon (IFN)-γ mRNA expression, whereas interleukin (IL)-2 expression remained unchanged. In contrast, gene transcription for the Th2-type cytokines IL-4 and IL-10 was diminished. In addition, with use of an in vitro lymphocyte-macrophage coculture system, an enhanced IFN-γ and a reduced IL-10 release were shown with cells from silicotic animals. With regard to IFN-γ-inducing cytokines, we observed enhanced IL-12 mRNA levels in vivo, whereas IL-18 gene expression was slightly decreased. These data indicate that a persistent shift toward an IFN-γ-dominated type 1 (Th1/cytotoxic T cell type 1) T-cell reaction pattern occurred within the thoracic lymph nodes of silicotic animals. Thus a mutual activation of lymphocytes and macrophages may maintain the chronic inflammatory changes that characterize silicosis.

T cell-T cell activation in multiple sclerosis

1997 ◽  
Vol 3 (4) ◽  
pp. 238-242 ◽  
Author(s):  
JW Lindsey ◽  
RH Kerman ◽  
JS Wolinsky
Keyword(s):  
Multiple Sclerosis ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Viral Infections ◽  
Activated T Cells ◽  
In Vitro Proliferation

Activated T cells are able to stimulate proliferation in resting T cells through an antigen non-specific mechanism. The in vivo usefulness of this T cell-T cell activation is unclear, but it may serve to amplify immune responses. T cell-T cell activation could be involved in the well-documented occurrence of multiple sclerosis (MS) exacerbations following viral infections. Excessive activation via this pathway could also be a factor in the etiology of MS. We tested the hypothesis that excessive T cell-T cell activation occurs in MS patients using in vitro proliferation assays comparing T cells from MS patients to T cells from controls. When tested as responder cells, T cells from MS patients proliferated slightly less after stimulation with previously activated cells than T cells from controls. When tested as stimulator cells, activated cells from MS patients stimulated slightly more non-specific proliferation than activated cells from controls. Neither of these differences were statistically significant We conclude that T cell proliferation in response to activated T cells is similar in MS and controls.

scholarly journals High-glucose-induced miR-214-3p inhibits BMSCs osteogenic differentiation in type 1 diabetes mellitus

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Rongze Wang ◽  
Yuanxu Zhang ◽  
Fujun Jin ◽  
Gongchen Li ◽  
Yao Sun ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Type 1 Diabetes ◽  
Type 1 Diabetes Mellitus ◽  
Osteogenic Differentiation ◽  
High Glucose ◽  
Bone Homeostasis ◽  
Marrow Mesenchymal Stem Cells

Abstract Type 1 diabetes mellitus (T1DM) is an autoimmune insulin-dependent disease associated with destructive bone homeostasis. Accumulating evidence has proven that miRNAs are widely involved in the regulation of bone homeostasis. However, whether miRNAs also regulate osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) in T1DM mice is under exploration. In this study, miRNA microarray was utilized to screen the differentially expressed miRNAs, which uncovered that miR-214-3p potentially inhibited BMSCs osteogenic differentiation in T1DM mice. We found that high glucose suppressed BMSCs osteogenic differentiation with significant elevation of the miR-214-3p expression. Further study found that the osteogenic differentiation of BMSCs was inhibited by AgomiR-214-3p while enhanced by AntagomiR-214-3p in BMSCs supplemented with high glucose. Moreover, we found that miR-214-3p knockout T1DM mice were resistant to high-glucose-induced bone loss. These results provide a novel insight into an inhibitory role of high-glucose-induced miR-214-3p in BMSCs osteogenic differentiation both in vitro and in vivo. Molecular studies revealed that miR-214-3p inhibits BMSCs osteogenic differentiation by targeting the 3′-UTR of β-catenin, which was further corroborated in human bone specimens and BMSCs of T1DM patients. Taken together, our study discovered that miR-214-3p is a pivotal regulator of BMSCs osteogenic differentiation in T1DM mice. Our findings also suggest that miR-214-3p could be a potential target in the treatment of bone disorders in patients with T1DM.

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