Autoimmune Diabetes In Mice Research Articles

Inhibition of the eukaryotic initiation factor-2α kinase PERK decreases risk of autoimmune diabetes in mice.

Preventing the onset of autoimmune type 1 diabetes (T1D) is feasible through pharmacological interventions that target molecular stress-responsive mechanisms. Cellular stresses, such as nutrient deficiency, viral infection, or unfolded proteins, trigger the integrated stress response (ISR), which curtails protein synthesis by phosphorylating eukaryotic translation initiation factor-2α (eIF2α). In T1D, maladaptive unfolded protein response (UPR) in insulin-producing β cells renders these cells susceptible to autoimmunity. We found that inhibition of the eIF2α kinase PKR-like ER kinase (PERK), a common component of the UPR and ISR, reversed the mRNA translation block in stressed human islets and delayed the onset of diabetes, reduced islet inflammation, and preserved β cell mass in T1D-susceptible mice. Single-cell RNA-Seq of islets from PERK-inhibited mice showed reductions in the UPR and PERK signaling pathways and alterations in antigen-processing and presentation pathways in β cells. Spatial proteomics of islets from these mice showed an increase in the immune checkpoint protein programmed death-ligand 1 (PD-L1) in β cells. Golgi membrane protein 1, whose levels increased following PERK inhibition in human islets and EndoC-βH1 human β cells, interacted with and stabilized PD-L1. Collectively, our studies show that PERK activity enhances β cell immunogenicity and that inhibition of PERK may offer a strategy for preventing or delaying the development of T1D.

ABIN1 is a negative regulator of effector functions in cytotoxic T cells

T cells are pivotal in the adaptive immune defense, necessitating a delicate balance between robust response against infections and self-tolerance. Their activation involves intricate cross-talk among signaling pathways triggered by the T-cell antigen receptors (TCR) and co-stimulatory or inhibitory receptors. The molecular regulation of these complex signaling networks is still incompletely understood. Here, we identify the adaptor protein ABIN1 as a component of the signaling complexes of GITR and OX40 co-stimulation receptors. T cells lacking ABIN1 are hyper-responsive ex vivo, exhibit enhanced responses to cognate infections, and superior ability to induce experimental autoimmune diabetes in mice. ABIN1 negatively regulates p38 kinase activation and late NF-κB target genes. P38 is at least partially responsible for the upregulation of the key effector proteins IFNG and GZMB in ABIN1-deficient T cells after TCR stimulation. Our findings reveal the intricate role of ABIN1 in T-cell regulation.

Inhibition of the Eukaryotic Initiation Factor-2-α Kinase PERK Decreases Risk of Autoimmune Diabetes in Mice.

Preventing the onset of autoimmune type 1 diabetes (T1D) is feasible through pharmacological interventions that target molecular stress-responsive mechanisms. Cellular stresses, such as nutrient deficiency, viral infection, or unfolded proteins, trigger the integrated stress response (ISR), which curtails protein synthesis by phosphorylating eIF2α. In T1D, maladaptive unfolded protein response (UPR) in insulin-producing β cells renders these cells susceptible to autoimmunity. We show that inhibition of the eIF2α kinase PERK, a common component of the UPR and ISR, reverses the mRNA translation block in stressed human islets and delays the onset of diabetes, reduces islet inflammation, and preserves β cell mass in T1D-susceptible mice. Single-cell RNA sequencing of islets from PERK-inhibited mice shows reductions in the UPR and PERK signaling pathways and alterations in antigen processing and presentation pathways in β cells. Spatial proteomics of islets from these mice shows an increase in the immune checkpoint protein PD-L1 in β cells. Golgi membrane protein 1, whose levels increase following PERK inhibition in human islets and EndoC-βH1 human β cells, interacts with and stabilizes PD-L1. Collectively, our studies show that PERK activity enhances β cell immunogenicity, and inhibition of PERK may offer a strategy to prevent or delay the development of T1D.

TIGIT acts as an immune checkpoint upon inhibition of PD1 signaling in autoimmune diabetes.

Chronic activation of self-reactive T cells with beta cell antigens results in the upregulation of immune checkpoint molecules that keep self-reactive T cells under control and delay beta cell destruction in autoimmune diabetes. Inhibiting PD1/PD-L1 signaling results in autoimmune diabetes in mice and humans with pre-existing autoimmunity against beta cells. However, it is not known if other immune checkpoint molecules, such as TIGIT, can also negatively regulate self-reactive T cells. TIGIT negatively regulates the CD226 costimulatory pathway, T-cell receptor (TCR) signaling, and hence T-cell function. The phenotype and function of TIGIT expressing islet infiltrating T cells was studied in non-obese diabetic (NOD) mice using flow cytometry and single cell RNA sequencing. To determine if TIGIT restrains self-reactive T cells, we used a TIGIT blocking antibody alone or in combination with anti-PDL1 antibody. We show that TIGIT is highly expressed on activated islet infiltrating T cells in NOD mice. We identified a subset of stem-like memory CD8+ T cells expressing multiple immune checkpoints including TIGIT, PD1 and the transcription factor EOMES, which is linked to dysfunctional CD8+ T cells. A known ligand for TIGIT, CD155 was expressed on beta cells and islet infiltrating dendritic cells. However, despite TIGIT and its ligand being expressed, islet infiltrating PD1+TIGIT+CD8+ T cells were functional. Inhibiting TIGIT in NOD mice did not result in exacerbated autoimmune diabetes while inhibiting PD1-PDL1 resulted in rapid autoimmune diabetes, indicating that TIGIT does not restrain islet infiltrating T cells in autoimmune diabetes to the same degree as PD1. Partial inhibition of PD1-PDL1 in combination with TIGIT inhibition resulted in rapid diabetes in NOD mice. These results suggest that TIGIT and PD1 act in synergy as immune checkpoints when PD1 signaling is partially impaired. Beta cell specific stem-like memory T cells retain their functionality despite expressing multiple immune checkpoints and TIGIT is below PD1 in the hierarchy of immune checkpoints in autoimmune diabetes.

Cell-Surface ZnT8 Antibody Prevents and Reverses Autoimmune Diabetes in Mice.

Type 1 diabetes (T1D) is an autoimmune disease where pathogenic lymphocytes target autoantigens expressed in the pancreatic islets, leading to the destruction of insulin-producing β-cells. Zinc transporter 8 (ZnT8) is a major autoantigen abundantly present on the β-cell surface. This unique molecular target offers the potential to shield β-cells against autoimmune attacks in T1D. Our previous work showed that a monoclonal antibody (mAb43) against cell-surface ZnT8 can home in on the pancreatic islets and prevent autoantibodies from recognizing β-cells. This study demonstrates that mAb43 binds to exocytotic sites on the β-cell surface, masking the antigenic exposure of ZnT8 and insulin following glucosestimulated insulin secretion. In vivo administration of mAb43 to nonobese diabetic (NOD) mice selectively increased the proportion of regulatory T-cells (Tregs) in the islet, resulting in complete and sustained protection against T1D onset as well as reversal of new-onset diabetes. The mAb43-induced self-tolerance was reversible after treatment cessation and exhibited no adverse effects during long-term monitoring. Our findings suggest that mAb43 masking of the antigenic exposure of β-cells suppresses the immunological cascade from B-cell antigen presentation to T-cell mediated β-cell destruction, providing a novel islet-targeted and antigen-specific immunotherapy to prevent and reverse clinical T1D.

Significant expansion of the donor pool achieved by utilizing islets of variable quality in the production of allogeneic "Neo-Islets", 3-D organoids of Mesenchymal Stromal and islet cells, a novel immune-isolating biotherapy for Type I Diabetes.

Novel biotherapies for Type 1 Diabetes that provide a significantly expanded donor pool and that deliver all islet hormones without requiring anti-rejection drugs are urgently needed. Scoring systems have improved islet allotransplantation outcomes, but their use may potentially result in the waste of valuable cells for novel therapies. To address these issues, we created "Neo-Islets" (NIs), islet-sized organoids, by co-culturing in ultralow adhesion flasks culture-expanded islet (ICs) and Mesenchymal Stromal Cells (MSCs) (x 24 hrs, 1:1 ratio). The MSCs exert powerful immune- and cyto-protective, anti-inflammatory, proangiogenic, and other beneficial actions in NIs. The robust in vitro expansion of all islet hormone-producing cells is coupled to their expected progressive de-differentiation mediated by serum-induced cell cycle entry and Epithelial-Mesenchymal Transition (EMT). Re-differentiation in vivo of the ICs and resumption of their physiological functions occurs by reversal of EMT and serum withdrawal-induced exit from the cell cycle. Accordingly, we reported that allogeneic, i.p.-administered NIs engraft in the omentum, increase Treg numbers and reestablish permanent normoglycemia in autoimmune diabetic NOD mice without immunosuppression. Our FDA-guided pilot study (INAD 012-0776) in insulin-dependent pet dogs showed similar responses, and both human- and canine-NIs established normoglycemia in STZ-diabetic NOD/SCID mice even though the utilized islets would be scored as unsuitable for transplantation. The present study further demonstrates that islet gene expression profiles (α, β, γ, δ) in human "non-clinical grade" islets obtained from diverse, non-diabetic human and canine donors (n = 6 each) closely correlate with population doublings, and the in vivo re-differentiation of endocrine islet cells clearly corresponds with the reestablishment of euglycemia in diabetic mice. Conclusion: human-NIs created from diverse, "non-clinical grade" donors have the potential to greatly expand patient access to this curative therapy of T1DM, facilitated by the efficient in vitro expansion of ICs that can produce ~ 270 therapeutic NI doses per donor for 70 kg recipients.

1808-PUB: Effective and Durable Stem-Cell-Enabled Therapy of Autoimmune T1DM in Rodents and Dogs Provides the Scientific Basis for the First-in-Human Trial Using I.P. Administered “Neo-Islets,” 3-D Organoids of Allogeneic Islet, and Mesenchymal Stromal Cells—The Omentum Becomes the New Endocrine Pancreas without the Need for Antirejection Drugs

Two initial reports from Clinical Trials with cell-based interventions for the urgently needed therapy of T1DM show: (a) Open, s.c.-placed encapsulation devices containing insulin-producing progenitor cells that require anti-rejection drugs have failed to adequately improve glycemic control. (b) The intraportal administration of stem cell-derived insulin-producing cells, requiring anti-rejection drugs, has shown promising results in 2 or 3 subjects. However, the inability to retrieve these cells and the need for anti-rejection drugs remain a concern. Our approach harnesses the immune-modulating and -isolating, anti-inflammatory, angiogenic, anti-apoptotic and other trophic actions of Mesenchymal Stromal Cells (MSCs). First, we demonstrated that allogeneic Neo-islets (NIs), islet-sized organoids composed of equal numbers of MSCs and culture expanded Islet Cells do, when given i.p., omentally engraft, redifferentiate, re-express all islet hormones and permanently restore euglycemia in auto-immune diabetic NOD mice, i.e., without encapsulation devices or antirejection drugs. The omentum becomes the new endocrine pancreas. Second, i.p. therapy of spontaneously diabetic pet dogs with allogeneic canine NIs significantly improved glycemia and insulin needs (> 3 years), and this without immune response (abstract this meeting). Third, human NIs permanently correct streptozotocin-induced diabetes in NOD/SCID mice. Removal of the omentally-engrafted NIs promptly restores the diabetic state. No long-term complications of the NI therapy have been observed. Based on this body of evidence, a successful Pre-IND meeting with the FDA was held and final Proof-of-Concept studies that are expected to lead IND approval are ongoing. Disclosure A.Gooch: Board Member; SymbioCellTech, LLC, Employee; SymbioCellTech, LLC, Stock/Shareholder; SymbioCellTech, LLC. C.Westenfelder: Board Member; SymbioCellTech, LLC., Employee; SymbioCellTech, LLC., Research Support; SymbioCellTech, LLC., Stock/Shareholder; SymbioCellTech, LLC.

Specific reprogramming of alpha cells to insulin-producing cells by short glucagon promoter-driven Pdx1 and MafA

Endogenous reprogramming of pancreas-derived non-beta cells into insulin-producing cells is a promising approach to treat type 1 diabetes (T1D). One strategy that has yet to be explored is the specific delivery of insulin-producing essential genes, Pdx1 and MafA, to pancreatic alpha cells to reprogram the cells into insulin-producing cells in an adult pancreas. In this study, we used an alpha cell-specific glucagon (GCG) promoter to drive Pdx1 and MafA transcription factors to reprogram alpha cells to insulin-producing cells in chemically induced and autoimmune diabetic mice. Our results showed that a combination of a short glucagon-specific promoter with AAV serotype 8 (AAV8) can be used to successfully deliver Pdx1 and MafA to pancreatic alpha cells in the mouse pancreas. Pdx1 and MafA expression specifically in alpha cells were also able to correct hyperglycemia in both induced and autoimmune diabetic mice. With this technology, targeted gene specificity and reprogramming were accomplished with an alpha-specific promotor combined with an AAV-specific serotype and provide an initial basis to develop a novel therapy for the treatment of T1D.

Regulatory T cells suppress the formation of potent KLRK1 and IL-7R expressing effector CD8 T cells by limiting IL-2.

Regulatory T cells (Tregs) are indispensable for maintaining self-tolerance by suppressing conventional T cells. On the other hand, Tregs promote tumor growth by inhibiting anticancer immunity. In this study, we identified that Tregs increase the quorum of self-reactive CD8+ T cells required for the induction of experimental autoimmune diabetes in mice. Their major suppression mechanism is limiting available IL-2, an essential T-cell cytokine. Specifically, Tregs inhibit the formation of a previously uncharacterized subset of antigen-stimulated KLRK1+ IL-7R+ (KILR) CD8+ effector T cells, which are distinct from conventional effector CD8+ T cells. KILR CD8+ T cells show superior cell-killing abilities in vivo. The administration of agonistic IL-2 immunocomplexes phenocopies the absence of Tregs, i.e., it induces KILR CD8+ T cells, promotes autoimmunity, and enhances antitumor responses in mice. Counterparts of KILR CD8+ T cells were found in the human blood, revealing them as a potential target for immunotherapy.

Bioluminescent Monitoring of Graft Survival in an Adoptive Transfer Model of Autoimmune Diabetes in Mice.

Type 1 diabetes is characterized by the autoimmune destruction of the insulin-producing beta cells of the pancreas. A promising treatment for this disease is the transplantation of stem cell-derived beta cells. Genetic modifications, however, may be necessary to protect the transplanted cells from persistent autoimmunity. Diabetic mouse models are a useful tool for the preliminary evaluation of strategies to protect transplanted cells from autoimmune attack. Described here is a minimally invasive method for transplanting and imaging cell grafts in an adoptive transfer model of diabetes in mice. In this protocol, cells from the murine pancreatic beta cell line NIT-1 expressing the firefly luciferase transgene luc2 are transplanted subcutaneously into immunodeficient non-obese diabetic (NOD)-severe combined immunodeficient (scid) mice. These mice are simultaneously injected intravenously with splenocytes from spontaneously diabetic NOD mice to transfer autoimmunity. The grafts are imaged at regular intervals via non-invasive bioluminescent imaging to monitor the cell survival. The survival of mutant cells is compared to that of control cells transplanted into the same mouse.

841-P: Scientific Basis for the First-in-Human Trial of “Neo-Islet”–Mediated Functional Cure of T1DM: The Intraperitoneal Administration of “Neo-Islets,” 3-D Organoids of Allogeneic Islet and Mesenchymal Stromal Cells from Rodents, Dogs, and Humans Durably Cures

Initial reports from Clinical Trials with cell-based interventions for the urgently needed therapy of T1DM show: (1) An open, s.c.-placed encapsulation device containing insulin-producing progenitor cells that require anti-rejection drugs has failed to adequately improve glycemic control. (2) The i.v. administration of stem cell-derived insulin-producing cells, requiring anti-rejection drugs, has shown promising results in 1 or 2 subjects. However, their unknown systemic location and inability to retrieve these cells remain a concern. Our approach harnesses the immune-modulating and -isolating, anti-inflammatory, angiogenic, anti-apoptotic and other trophic actions of Mesenchymal Stromal Cells (MSCs) . First, we demonstrated that allogeneic Neo-islets (NIs) , islet-sized organoids composed of equal numbers of MSCs and culture expanded Islet Cells do, when given i.p., omentally engraft, redifferentiate, re-express all islet hormones (Abstract this meeting) and permanently restore euglycemia in auto-immune diabetic NOD mice, i.e., without encapsulation devices or antirejection drugs. The omentum becomes the new endocrine pancreas. Second, i.p. therapy of spontaneously diabetic pet dogs with allogeneic canine NIs significantly improved glycemia and insulin needs (> 3 years) , and this without immune response. Third, human NIs permanently correct streptozotocin-induced diabetes in NOD/SCID mice. Removal of the omentally-engrafted NIs promptly restores the diabetic state. No long-term complications of the NI therapy have been observed. Based on this body of evidence, a successful Pre-IND meeting with the FDA was held and final Proof-of-Concept studies that are expected to lead IND approval are ongoing. Disclosure C.Westenfelder: None. S.S.Chowdhury: Employee; SymbioCellTech, LLC. A.Gooch: Board Member; SymbioCellTech, LLC., Employee; SymbioCellTech, LLC., Stock/Shareholder; SymbioCellTech, LLC.

760-P: Allogeneic "Neo-Islets," Organoids Composed of Cultured Pancreatic Islet and Mesenchymal Stromal Cells from Diverse Donors, Afford a Marked Increase in the Global Availability of a Curative, Novel, Anti-Rejection-Drug-Independent Biotherapy of T1DM

The scarcity of suitable pancreas/islet donors, the life-long need for potentially toxic anti-rejection drugs for transplants and certain biotherapies, and failure of some immune-isolating encapsulation devices collectively warrant the urgent development of novel therapies for T1DM that significantly expand the donor pool without reliance on anti-rejection drugs. Allogeneic, i.p.-administered “Neo-Islets” (NIs) are potentially such a therapy. We previously reported that the use of NIs reestablished permanent normoglycemia in autoimmune diabetic NOD mice without immunosuppression. Our FDA-guided pilot study (INAD 012-0776) in insulin dependent, spontaneously diabetic pet dogs showed similar, durable responses, also without immunosuppression. Scoring systems have improved allotransplantation outcomes while their use may actually waste potentially valuable cells for novel diabetes therapies such as NIs. In preparation for a Phase 1 clinical trial with NIs, we examined whether human “non-clinical grade” islets from diverse, nondiabetic human and canine donors (n=6-8 each) could be processed to generate fully functioning NIs. Islet gene expression profiles (insulin, others) in both species closely correlate with population doublings and GSIS responses. Human-NIs establish normoglycemia in STZ diabetic NOD/SCID mice. Based on these results, an estimated 600 therapeutic doses can be generated from a single islet donor. Conclusion: human-NIs created from diverse, “non-clinical grade” donors have the potential to greatly expand patient access to this curative therapy, facilitated by biotherapy-specific adjustments in the current scoring systems. Disclosure C. Westenfelder: Consultant; Self; SymbioCellTech. S. S. Chowdhury: Employee; Self; SymbioCellTech. A. Gooch: Employee; Self; SymbioCellTech.

Intestinal delivery of proinsulin and IL-10 via Lactococcus lactis combined with low-dose antiCD3 induces antigen-specific FoxP3+ Tregs in autoimmune diabetic mice

Intestinal delivery of proinsulin and IL-10 via <i>Lactococcus lactis</i> combined with low-dose antiCD3 induces antigen-specific FoxP3+ Tregs in autoimmune diabetic mice

Intestinal Delivery of Proinsulin and IL-10 via Lactococcus lactis Combined With Low-Dose Anti-CD3 Restores Tolerance Outside the Window of Acute Type 1 Diabetes Diagnosis.

A combination treatment (CT) of proinsulin and IL-10 orally delivered via genetically modified Lactococcus lactis bacteria combined with low-dose anti-CD3 (aCD3) therapy successfully restores glucose homeostasis in newly diagnosed non-obese diabetic (NOD) mice. Tolerance is accompanied by the accumulation of Foxp3+ regulatory T cells (Tregs) in the pancreas. To test the potential of this therapy outside the window of acute diabetes diagnosis, we substituted autoimmune diabetic mice, with disease duration varying between 4 and 53 days, with syngeneic islets at the time of therapy initiation. Untreated islet recipients consistently showed disease recurrence after 8.2 ± 0.7 days, while 32% of aCD3-treated and 48% of CT-treated mice remained normoglycemic until 6 weeks after therapy initiation (P < 0.001 vs. untreated controls for both treatments, P < 0.05 CT vs. aCD3 therapy). However, mice that were diabetic for more than 2 weeks before treatment initiation were less efficient at maintaining normoglycemia than those treated within 2 weeks of diabetes diagnosis, particularly in the aCD3-treated group. The complete elimination of endogenous beta cell mass with alloxan at the time of diabetes diagnosis pointed toward the significance of continuous feeding of the islet antigen proinsulin at the time of aCD3 therapy for treatment success. The CT providing proinsulin protected 69% of mice, compared to 33% when an irrelevant antigen (ovalbumin) was combined with aCD3 therapy, or to 27% with aCD3 therapy alone. Sustained tolerance was accompanied with a reduction of IGRP+CD8+ autoreactive T cells and an increase in insulin-reactive (InsB12–20 or InsB13–2) Foxp3+CD4+ Tregs, with a specific accumulation of Foxp3+ Tregs around the insulin-containing islet grafts after CT with proinsulin. The combination of proinsulin and IL-10 via oral Lactococcus lactis with low-dose aCD3 therapy can restore tolerance to beta cells in autoimmune diabetic mice, also when therapy is started outside the window of acute diabetes diagnosis, providing persistence of insulin-containing islets or prolonged beta cell function.

204-LB: The In Vitro Characteristics of Human Islet Cells from Diverse Donors, Coaggregated with Human Mesenchymal Stromal Cells to form “Neo-islets”, Are Consistently Identical: Relevance to Clinical Trials in Diabetic Subjects

We reported that allogeneic “Neo-Islets” (NIs), organoids composed of ~ equal numbers of Mesenchymal Stromal Cells and culture expanded Islet Cells (ICs) do, when given i.p., omentally engraft and permanently restore euglycemia in auto-immune diabetic NOD mice, i.e., without the use of either encapsulation devices or antirejection drugs. Similarly, spontaneously diabetic pet dogs treated with allogeneic canine NIs (cNIs) significantly improve glycemia with ~ 50% reduction in insulin needs (&amp;gt; 2 years), and this without immune response. In preparation for a Phase I Clinical Trial we tested whether human ICs in NIs (hNIs) are biologically comparable to canine Islet Cells (cICs) and cNIs, i.e., cells from a larger diabetes model. In our preclinical mouse and dog studies, insulin and other islet hormone gene expression levels were used as indicators of ICs in NIs to adequately re-differentiate into insulin and islet-specific endocrine cells when implanted i.p., thereby resulting in physiological control of T1DM.Human islet cells from 6 donors of different demographics were cultured, passaged to P4, and their growth rates, insulin and other islet-associated endocrine genes’ expression levels, secretion of insulin in response to glucose stimulation (GSIS), and NI formation abilities were compared. Results: (1) hICs and hNIs show comparable gene expression profiles to those of cICs and cNIs, and hNIs show identical GSIS responses to those of cNIs. (2) Insulin gene expression profiles of hICs are stable as a function of population doublings and independent of donor diversity. In conclusion, these data indicate that donor variability does not appear to be a significant factor in this NI technology, facilitating our IND work and further demonstrating hNIs’ translational potential in a planned Clinical Trial in subjects with T1DM. Disclosure A. Gooch: Employee; Self; SymbioCellTech. S.S. Chowdhury: Employee; Self; SymbioCellTech. P. Zhang: Employee; Self; SymbioCellTech. Z. Hu: Employee; Self; SymbioCellTech. C. Westenfelder: Consultant; Self; SymbioCellTech.

436-P: Characterization of Autoimmunity in the Acceleration of Atherosclerosis in Type 1 Diabetes

Hyperglycemia, hyperlipidemia and hypertension have been evaluated extensively as risk factors for cardiovascular disease (CVD) in people with type 1 diabetes (T1DM). However, the impact of autoimmunity in T1DM on CVD has not been determined. We have generated several mice models of atherosclerosis including ApoE-/-/NOD, ApoE-/-/NOD (congenic non diabetes and non-autoimmune), ApoE-/-/NOD (autoimmunity with insulitis, nondiabetes) and ApoE-/-/NOD autoimmune diabetic mice. All groups of mice have high plasma lipids but only ApoE-/-/NOD diabetic mice had hyperglycemia. However, ApoE-/-/NOD (insulitis and nondiabetes) and ApoE-/-/NOD (insulitis and diabetes) had high titers of autoantibodies to IA2 compared to control CongApoE-/-/NOD mice or nondiabetic ApoE-/-/NOD mice (P&amp;lt;0.0001). For the the severity of atherosclerosis, the presence of hyperglycemia in ApoE-/-/NOD-DM mice showed greater levels of lipid deposition in the descending aorta (22%) by en face assessment as compared to nondiabetic ApoE-/-/NOD mice (P&amp;lt;0.01). Similarly, we also observed in the macrophage content of the descending aorta, was greater in numbers in the ApoE-/-/NOD mice than in ApoE-/-/CongNOD mice (P&amp;lt;0.05) but less than in ApoE-/-/NOD-DM mice. FACS of the descending aorta showed the elevated CD3+/CD28- T-cells (CD4 and CD8) by 4.5 folds and decreased CD3+/CD28+ Treg cells by 46% at the atherosclerotic plaques of ApoE-/-/NOD mice, compared to those of CongApoE-/-/NOD mice. To further confirm the elevated infiltrate and accumulated CD3+ T-cells in vivo, we will investigate the levels of macrophages and CD3+ T-cells in the arterial wall of the coronary artery from the Medalists group T1D and autoimmunity with positive HLA DR3/4 risk alleles and autoantibodies and lacking monogenic diabetic variants, as compared to the group lacking HLA DR3/4 risk alleles and autoantibodies. These studies suggest that autoimmunity exacerbates atherosclerosis in T1D, independently and synergically hyperglycemia. Disclosure K. Park: None. Q. Li: None. H. Park: None. R. St-Louis: None. J. Fu: None. C. Rask-Madsen: None. E. Maddaloni: Consultant; Self; Merck KGaA. Speaker’s Bureau; Self; Abbott, AstraZeneca, Pikdare. H. Yokomizo: None. S. Kissler: None. A.H. Lichtman: None. G.L. King: Research Support; Self; Janssen Pharmaceuticals, Inc. Funding National Institutes of Health (R01DK053105); Thomas J. Beatson, Jr. Foundation

PAHSAs attenuate immune responses and promote β cell survival in autoimmune diabetic mice.

Palmitic acid esters of hydroxy stearic acids (PAHSAs) are endogenous antidiabetic and antiinflammatory lipids. Here, we show that PAHSAs protect against type 1 diabetes (T1D) and promote β cell survival and function. Daily oral PAHSA administration to nonobese diabetic (NOD) mice delayed the onset of T1D and markedly reduced the incidence of T1D, whether PAHSAs were started before or after insulitis was established. PAHSAs reduced T and B cell infiltration and CD4+ and CD8+ T cell activation, while increasing Treg activation in pancreata of NOD mice. PAHSAs promoted β cell proliferation in both NOD mice and MIN6 cells and increased the number of β cells in NOD mice. PAHSAs attenuated cytokine-induced apoptotic and necrotic β cell death and increased β cell viability. The mechanism appears to involve a reduction of ER stress and MAPK signaling, since PAHSAs lowered ER stress in NOD mice, suppressed thapsigargin-induced PARP cleavage in human islets, and attenuated ERK1/2 and JNK1/2 activation in MIN6 cells. This appeared to be mediated in part by glucagon-like peptide 1 receptor (GLP-1R) and not the G protein-coupled receptor GPR40. PAHSAs also prevented impairment of glucose-stimulated insulin secretion and improved glucose tolerance in NOD mice. Thus, PAHSAs delayed the onset of T1D and reduced its incidence by attenuating immune responses and exerting direct protective effects on β cell survival and function.

British Society for Gene and Cell Therapy Autumn Conference Friday 23 November 2018 Regent's University Conference Centre, London, UK www.bsgct.org

British Society for Gene and Cell Therapy Autumn Conference Friday 23 November 2018 Regent's University Conference Centre, London, UK www.bsgct.org

Immunosuppression overcomes insulin- and vector-specific immune responses that limit efficacy of AAV2/8-mediated insulin gene therapy in NOD mice

We report the restoration of euglycaemia in chemically induced diabetic C57BL/6 mice and spontaneously diabetic Non Obese Diabetic (NOD) mice by intravenous systemic administration of a single-stranded adeno-associated virus (ssAAV2/8) codon optimised (co) vector encoding furin cleavable human proinsulin under a liver-specific promoter. There were no immunological barriers to efficacy of insulin gene therapy in chemically induced C57BL/6 mice, which enjoyed long-lasting correction of hyperglycaemia after therapy, up to 250 days. Euglycaemia was also restored in spontaneously diabetic NOD mice, although these mice required a 7–10-fold higher dose of vector to achieve similar efficacy as the C57BL/6 mice and the immunodeficient NODscid mice. We detected CD8+ T cell reactivity to insulin and mild inflammatory infiltration in the livers of gene therapy recipient NOD mice, neither of which were observed in the treated C57BL/6 mice. Efficacy of the gene therapy in NOD mice was partially improved by targeting the immune system with anti-CD4 antibody treatment, while transfer of NOD mouse AAV2/8-reactive serum to recipients prevented successful restoration of euglycaemia in AAV2/8-HLP-hINSco-treated NODscid mice. Our data indicate that both immune cells and antibodies form a barrier to successful restoration of euglycaemia in autoimmune diabetic recipient mice with insulin gene therapy, but that this barrier can be overcome by increasing the dose of vector and by suppressing immune responses.

Simultaneous Recognition of Allogeneic MHC and Cognate Autoantigen by Autoreactive T Cells in Transplant Rejection.

The autoimmune condition is a primary obstacle to inducing tolerance in type 1 diabetes patients receiving allogeneic pancreas transplants. It is unknown how autoreactive T cells that recognize self-MHC molecules contribute to MHC-disparate allograft rejection. In this report, we show the presence and accumulation of dual-reactive, that is autoreactive and alloreactive, T cells in C3H islet allografts that were transplanted into autoimmune diabetic NOD mice. Using high-throughput sequencing, we discovered that T cells prevalent in allografts share identical TCRs with autoreactive T cells present in pancreatic islets. T cells expressing TCRs that are enriched in allograft lesions recognized C3H MHC molecules, and five of six cell lines expressing these TCRs were also reactive to NOD islet cells. These results reveal the presence of autoreactive T cells that mediate cross-reactive alloreactivity, and indicate a requirement for regulating such dual-reactive T cells in tissue replacement therapies given to autoimmune individuals.