Genetic Control of Splicing at SIRPG Modulates Risk of Type 1 Diabetes

10.2337/figshare.17026610.v1 ◽

2021 ◽

Author(s):

Morgan J. Smith ◽

Lucia Pastor ◽

Jeremy R.B. Newman ◽

Patrick Concannon

Keyword(s):

T Cells ◽

Type 1 Diabetes ◽

Alternative Splicing ◽

Cell Surface ◽

Regulatory Protein ◽

Jurkat Cells ◽

Causative Gene ◽

Transcript Isoforms

Signal regulatory protein SIRPγ (CD172G) is expressed on the surface of lymphocytes where it acts by engaging its ligand, CD47. SIRPG, which encodes SIRPγ, contains a non-synonymous coding variant, rs6043409, which is significantly associated with risk for type 1 diabetes. SIRPG produces multiple transcript isoforms via alternative splicing, all encoding potentially functional proteins. We show that rs6043409 alters a predicted exonic splicing enhancer, resulting in significant shifts in the distribution of SIRPG transcript isoforms. All of these transcript isoforms produced protein upon transient expression in vitro. However, CRISPR targeting of one of the alternatively spliced exons in SIRPG eliminated all SIRPγ expression in Jurkat T cells. These targeted cells formed fewer cell-cell conjugates with each other than with wild type Jurkat cells, expressed reduced levels of genes associated with CD47 signaling and had significantly increased levels of cell surface CD47. In primary CD4+ and CD8+ T cells cell surface SIRPγ levels in response to anti-CD3 stimulation varied quantitatively by rs6043409 genotype. Our results suggest that SIRPG is the most likely causative gene for type 1 diabetes risk in the 20p13 region and highlight the role of alternative splicing in lymphocytes in mediating the genetic risk for autoimmunity.

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Dextran Sulfate Protects Pancreatic β-Cells, Reduces Autoimmunity and Ameliorates Type 1 Diabetes

10.2337/figshare.12245363.v1 ◽

2020 ◽

Author(s):

Ada Admin ◽

Geming Lu ◽

Francisco Rausell-Palamos ◽

Jiamin Zhang ◽

Zihan Zheng ◽

...

Keyword(s):

T Cells ◽

Type 1 Diabetes ◽

Heparan Sulfate ◽

Dextran Sulfate ◽

Nod Mice ◽

Β Cells ◽

Β Cell ◽

Pancreatic Β Cells

A failure in self-tolerance leads to autoimmune destruction of pancreatic β-cells and type 1 diabetes (T1D). Low molecular weight dextran sulfate (DS) is a sulfated semi-synthetic polysaccharide with demonstrated cytoprotective and immunomodulatory properties in vitro. However, whether DS can protect pancreatic β-cells, reduce autoimmunity and ameliorate T1D is unknown. Here we report that DS, but not dextran, protects human β-cells against cytokine-mediated cytotoxicity in vitro. DS also protects mitochondrial function and glucose-stimulated insulin secretion and reduces chemokine expression in human islets in a pro-inflammatory environment. Interestingly, daily treatment with DS significantly reduces diabetes incidence in pre-diabetic non-obese diabetic (NOD) mice, and most importantly, reverses diabetes in early-onset diabetic NOD mice. DS decreases β-cell death, enhances islet heparan sulfate (HS)/heparan sulfate proteoglycan (HSPG) expression and preserves β-cell mass and plasma insulin in these mice. DS administration also increases the expression of the inhibitory co-stimulatory molecule programmed death-1 (PD-1) in T-cells, reduces interferon-γ+ CD4+ and CD8+ T-cells and enhances the number of FoxP3+ cells. Collectively, these studies demonstrate that the action of one single molecule, DS, on β-cell protection, extracellular matrix preservation and immunomodulation can reverse diabetes in NOD mice highlighting its therapeutic potential for the treatment of T1D.

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Glycolysis Inhibition Induces Functional and Metabolic Exhaustion of CD4+ T Cells in Type 1 Diabetes

Frontiers in Immunology ◽

10.3389/fimmu.2021.669456 ◽

2021 ◽

Vol 12 ◽

Author(s):

Christina P. Martins ◽

Lee A. New ◽

Erin C. O’Connor ◽

Dana M. Previte ◽

Kasey R. Cargill ◽

...

Keyword(s):

T Cells ◽

Type 1 Diabetes ◽

T Cell ◽

Cell Function ◽

T Cell Responses ◽

Metabolic Reprogramming ◽

Cell Responses ◽

T Cell Function

In Type 1 Diabetes (T1D), CD4+ T cells initiate autoimmune attack of pancreatic islet β cells. Importantly, bioenergetic programs dictate T cell function, with specific pathways required for progression through the T cell lifecycle. During activation, CD4+ T cells undergo metabolic reprogramming to the less efficient aerobic glycolysis, similarly to highly proliferative cancer cells. In an effort to limit tumor growth in cancer, use of glycolytic inhibitors have been successfully employed in preclinical and clinical studies. This strategy has also been utilized to suppress T cell responses in autoimmune diseases like Systemic Lupus Erythematosus (SLE), Multiple Sclerosis (MS), and Rheumatoid Arthritis (RA). However, modulating T cell metabolism in the context of T1D has remained an understudied therapeutic opportunity. In this study, we utilized the small molecule PFK15, a competitive inhibitor of the rate limiting glycolysis enzyme 6-phosphofructo-2-kinase/fructose-2,6- biphosphatase 3 (PFKFB3). Our results confirmed PFK15 inhibited glycolysis utilization by diabetogenic CD4+ T cells and reduced T cell responses to β cell antigen in vitro. In an adoptive transfer model of T1D, PFK15 treatment delayed diabetes onset, with 57% of animals remaining euglycemic at the end of the study period. Protection was due to induction of a hyporesponsive T cell phenotype, characterized by increased and sustained expression of the checkpoint molecules PD-1 and LAG-3 and downstream functional and metabolic exhaustion. Glycolysis inhibition terminally exhausted diabetogenic CD4+ T cells, which was irreversible through restimulation or checkpoint blockade in vitro and in vivo. In sum, our results demonstrate a novel therapeutic strategy to control aberrant T cell responses by exploiting the metabolic reprogramming of these cells during T1D. Moreover, the data presented here highlight a key role for nutrient availability in fueling T cell function and has implications in our understanding of T cell biology in chronic infection, cancer, and autoimmunity.

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Dextran Sulfate Protects Pancreatic β-Cells, Reduces Autoimmunity and Ameliorates Type 1 Diabetes

10.2337/figshare.12245363 ◽

2020 ◽

Author(s):

Ada Admin ◽

Geming Lu ◽

Francisco Rausell-Palamos ◽

Jiamin Zhang ◽

Zihan Zheng ◽

...

Keyword(s):

T Cells ◽

Type 1 Diabetes ◽

Heparan Sulfate ◽

Dextran Sulfate ◽

Nod Mice ◽

Β Cells ◽

Β Cell ◽

Pancreatic Β Cells

A failure in self-tolerance leads to autoimmune destruction of pancreatic β-cells and type 1 diabetes (T1D). Low molecular weight dextran sulfate (DS) is a sulfated semi-synthetic polysaccharide with demonstrated cytoprotective and immunomodulatory properties in vitro. However, whether DS can protect pancreatic β-cells, reduce autoimmunity and ameliorate T1D is unknown. Here we report that DS, but not dextran, protects human β-cells against cytokine-mediated cytotoxicity in vitro. DS also protects mitochondrial function and glucose-stimulated insulin secretion and reduces chemokine expression in human islets in a pro-inflammatory environment. Interestingly, daily treatment with DS significantly reduces diabetes incidence in pre-diabetic non-obese diabetic (NOD) mice, and most importantly, reverses diabetes in early-onset diabetic NOD mice. DS decreases β-cell death, enhances islet heparan sulfate (HS)/heparan sulfate proteoglycan (HSPG) expression and preserves β-cell mass and plasma insulin in these mice. DS administration also increases the expression of the inhibitory co-stimulatory molecule programmed death-1 (PD-1) in T-cells, reduces interferon-γ+ CD4+ and CD8+ T-cells and enhances the number of FoxP3+ cells. Collectively, these studies demonstrate that the action of one single molecule, DS, on β-cell protection, extracellular matrix preservation and immunomodulation can reverse diabetes in NOD mice highlighting its therapeutic potential for the treatment of T1D.

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Inducible regulatory T cells (iTregs) from recent-onset type 1 diabetes subjects show increased in vitro suppression and higher ITCH levels compared with controls

Cell and Tissue Research ◽

10.1007/s00441-009-0900-0 ◽

2010 ◽

Vol 339 (3) ◽

pp. 585-595 ◽

Cited By ~ 15

Author(s):

Sanja Glisic ◽

Sarah Ehlenbach ◽

Parthav Jailwala ◽

Jill Waukau ◽

Srikanta Jana ◽

...

Keyword(s):

T Cells ◽

Type 1 Diabetes ◽

Regulatory T Cells ◽

Recent Onset ◽

Onset Type

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

10.2337/figshare.12311675.v1 ◽

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+ 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+ T cells and diabetes protection by central memory CD8+ T cells in vivo. Taken together, these studies demonstrate that there is a protective role for central memory CD8+ 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.

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

Science Translational Medicine ◽

10.1126/scitranslmed.aag1782 ◽

2018 ◽

Vol 10 (422) ◽

pp. eaag1782 ◽

Cited By ~ 25

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.

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Selective Expression of a Stable Cell Surface Molecule on Type 2 but Not Type 1 Helper T Cells

Journal of Experimental Medicine ◽

10.1084/jem.187.5.787 ◽

1998 ◽

Vol 187 (5) ◽

pp. 787-794 ◽

Cited By ~ 382

Author(s):

Damo Xu ◽

Woon Ling Chan ◽

Bernard P. Leung ◽

Fang-ping Huang ◽

Rachel Wheeler ◽

...

Keyword(s):

T Cells ◽

Cell Surface ◽

Leishmania Major ◽

Flow Cytometric Analysis ◽

Dependent Manner ◽

Cell Surface Molecule ◽

Ifn Γ

T helper cell type 1 (Th1) and 2 (Th2) are central to immune regulation. However, no stable cell surface marker capable of distinguishing and separating these two subsets of CD4+ cells has yet been found. Using differential display PCR, we have identified a gene encoding a cell membrane bound molecule, originally designated ST2L, T1, DER4, or Fit, expressed constitutively and stably on the surface of murine Th2s, but not Th1s even after stimulation with a range of immunological stimuli. Antibody against a peptide derived from ST2L strongly and stably labeled the surface of cloned Th2s but not Th1s, and Th2s but not Th1s derived from naive T cells of ovalbumin T cell receptor–α/β transgenic mice. Three-color single cell flow cytometric analysis shows that cell surface ST2L coexpressed with intracellular interleukin (IL)-4, but not with interferon (IFN)-γ. The antibody selectively lysed Th2s in vitro in a complement-dependent manner. In vivo, it enhanced Th1 responses by increasing IFN-γ production and decreasing IL-4 and IL-5 synthesis. It induced resistance to Leishmania major infection in BALB/c mice and exacerbated collagen-induced arthritis in DBA/1 mice. Thus, ST2L is a stable marker distinguishing Th2s from Th1s and is also associated with Th2 functions. Hence, it may be a target for therapeutic intervention.

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

10.2337/figshare.12311675 ◽

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+ 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+ T cells and diabetes protection by central memory CD8+ T cells in vivo. Taken together, these studies demonstrate that there is a protective role for central memory CD8+ 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.

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