Autologous regulatory T cells for the treatment of type 1 diabetes

Arrest in the Progression of Type 1 Diabetes at the Mid-Stage of Insulitic Autoimmunity Using an Autoantigen-Decorated All-trans Retinoic Acid and Transforming Growth Factor Beta-1 Single Microparticle Formulation

Type 1 diabetes (T1D) is a disorder of impaired glucoregulation due to lymphocyte-driven pancreatic autoimmunity. Mobilizing dendritic cells (DC) in vivo to acquire tolerogenic activity is an attractive therapeutic approach as it results in multiple and overlapping immunosuppressive mechanisms. Delivery of agents that can achieve this, in the form of micro/nanoparticles, has successfully prevented a number of autoimmune conditions in vivo. Most of these formulations, however, do not establish multiple layers of immunoregulation. all-trans retinoic acid (RA) together with transforming growth factor beta 1 (TGFβ1), in contrast, has been shown to promote such mechanisms. When delivered in separate nanoparticle vehicles, they successfully prevent the progression of early-onset T1D autoimmunity in vivo. Herein, we show that the approach can be simplified into a single microparticle formulation of RA + TGFβ1 with surface decoration with the T1D-relevant insulin autoantigen. We show that the onset of hyperglycemia is prevented when administered into non-obese diabetic mice that are at the mid-stage of active islet-selective autoimmunity. Unexpectedly, the preventive effects do not seem to be mediated by increased numbers of regulatory T-lymphocytes inside the pancreatic lymph nodes, at least following acute administration of microparticles. Instead, we observed a mild increase in the frequency of regulatory B-lymphocytes inside the mesenteric lymph nodes. These data suggest additional and potentially-novel mechanisms that RA and TGFβ1 could be modulating to prevent progression of mid-stage autoimmunity to overt T1D. Our data further strengthen the rationale to develop RA+TGFβ1-based micro/nanoparticle “vaccines” as possible treatments of pre-symptomatic and new-onset T1D autoimmunity.

Expansion of Human Tregs from Cryopreserved Umbilical Cord Blood for GMP-Compliant Autologous Adoptive Cell Transfer Therapy

Umbilical cord blood is a traditional and convenient source of cells for hematopoietic stem cell transplantation. Thymic regulatory T cells (Tregs) are also present in cord blood, and there is growing interest in the use of autologous Tregs to provide a low-risk, fully human leukocyte antigen (HLA)-matched cell product for treating autoimmune diseases, such as type 1 diabetes. Here, we describe a good manufacturing practice (GMP)-compatible Treg expansion protocol using fluorescence-activated cell sorting, resulting in a mean 2,092-fold expansion of Tregs over a 16-day culture for a median yield of 1.26 × 10⁹ Tregs from single-donor cryopreserved units. The resulting Tregs passed prior clinical trial release criteria for Treg purity and sterility, including additional rigorous assessments of FOXP3 and Helios expression and epigenetic analysis of the FOXP3 Treg-specific demethylated region (TSDR). Compared with expanded adult peripheral blood Tregs, expanded cord blood Tregs remained more naive, as assessed by continued expression of CD45RA, produced reduced IFN-γ following activation, and effectively inhibited responder T cell proliferation. Immunosequencing of the T cell receptor revealed a remarkably diverse receptor repertoire within cord blood Tregs that was maintained following in vitro expansion. These data support the feasibility of generating GMP-compliant Tregs from cord blood for adoptive cell transfer therapies and highlight potential advantages in terms of safety, phenotypic stability, autoantigen specificity, and tissue distribution.

Tolerogenic nanoparticles inhibit T cell-mediated autoimmunity through SOCS2

Type 1 diabetes (T1D) is a T cell-dependent autoimmune disease that is characterized by the destruction of insulin-producing β cells in the pancreas. The administration to patients of ex vivo-differentiated FoxP3(+) regulatory T (Treg) cells or tolerogenic dendritic cells (DCs) that promote Treg cell differentiation is considered a potential therapy for T1D; however, cell-based therapies cannot be easily translated into clinical practice. We engineered nanoparticles (NPs) to deliver both a tolerogenic molecule, the aryl hydrocarbon receptor (AhR) ligand 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE), and the β cell antigen proinsulin (NPITE+Ins) to induce a tolerogenic phenotype in DCs and promote Treg cell generation in vivo. NPITE+Ins administration to 8-week-old nonobese diabetic mice suppressed autoimmune diabetes. NPITE+Ins induced a tolerogenic phenotype in DCs, which was characterized by a decreased ability to activate inflammatory effector T cells and was concomitant with the increased differentiation of FoxP3(+) Treg cells. The induction of a tolerogenic phenotype in DCs by NPs was mediated by the AhR-dependent induction of Socs2, which resulted in inhibition of nuclear factor κB activation and proinflammatory cytokine production (properties of tolerogenic DCs). Together, these data suggest that NPs constitute a potential tool to reestablish tolerance in T1D and potentially other autoimmune disorders.

Neoantigens and Microenvironment in Type 1 Diabetes: Lessons from Antitumor Immunity

Type 1 diabetes (T1D) is characterized by the selective and progressive destruction of insulin-producing beta cells by the immune system. An incomplete thymic selection against self-reactive islet antigens partly explains how these T cells reach the periphery and become diabetogenic. Increasing evidence suggest that beta cells themselves also participate to their own demise by generating neoepitopes that could be recognized by the immune surveillance machinery. In this regard, these T cells eradicate self-tissue by mechanisms analogous to a classical antitumor response. Cancer immunotherapy has exploited mutations and transcriptional and translational errors to trigger a specific antitumor response. In this opinion article, we aim at merging insight in antitumor immunology and autoimmunity to reveal processes that had previously been ignored to create beta cell-specific neoantigens.

Toward beta cell replacement for diabetes

The discovery of insulin more than 90 years ago introduced a life-saving treatment for patients with type 1 diabetes, and since then, significant progress has been made in clinical care for all forms of diabetes. However, no method of insulin delivery matches the ability of the human pancreas to reliably and automatically maintain glucose levels within a tight range. Transplantation of human islets or of an intact pancreas can in principle cure diabetes, but this approach is generally reserved for cases with simultaneous transplantation of a kidney, where immunosuppression is already a requirement. Recent advances in cell reprogramming and beta cell differentiation now allow the generation of personalized stem cells, providing an unlimited source of beta cells for research and for developing autologous cell therapies. In this review, we will discuss the utility of stem cell-derived beta cells to investigate the mechanisms of beta cell failure in diabetes, and the challenges to develop beta cell replacement therapies. These challenges include appropriate quality controls of the cells being used, the ability to generate beta cell grafts of stable cellular composition, and in the case of type 1 diabetes, protecting implanted cells from autoimmune destruction without compromising other aspects of the immune system or the functionality of the graft. Such novel treatments will need to match or exceed the relative safety and efficacy of available care for diabetes.

Restoring the balance: immunotherapeutic combinations for autoimmune disease

Autoimmunity occurs when T cells, B cells or both are inappropriately activated, resulting in damage to one or more organ systems. Normally, high-affinity self-reactive T and B cells are eliminated in the thymus and bone marrow through a process known as central immune tolerance. However, low-affinity self-reactive T and B cells escape central tolerance and enter the blood and tissues, where they are kept in check by complex and non-redundant peripheral tolerance mechanisms. Dysfunction or imbalance of the immune system can lead to autoimmunity, and thus elucidation of normal tolerance mechanisms has led to identification of therapeutic targets for treating autoimmune disease. In the past 15 years, a number of disease-modifying monoclonal antibodies and genetically engineered biologic agents targeting the immune system have been approved, notably for the treatment of rheumatoid arthritis, inflammatory bowel disease and psoriasis. Although these agents represent a major advance, effective therapy for other autoimmune conditions, such as type 1 diabetes, remain elusive and will likely require intervention aimed at multiple components of the immune system. To this end, approaches that manipulate cells ex vivo and harness their complex behaviors are being tested in preclinical and clinical settings. In addition, approved biologic agents are being examined in combination with one another and with cell-based therapies. Substantial development and regulatory hurdles must be overcome in order to successfully combine immunotherapeutic biologic agents. Nevertheless, such combinations might ultimately be necessary to control autoimmune disease manifestations and restore the tolerant state.

GITR+ regulatory T cells in the treatment of autoimmune diseases

Autoimmune diseases decrease life expectancy and quality of life for millions of women and men. Although treatments can slow disease progression and improve quality of life, all currently available drugs have adverse effects and none of them are curative; therefore, requiring patients to take immunosuppressive drugs for the remainder of their lives. A curative therapy that is safe and effective is urgently needed. We believe that therapies promoting the in vivo expansion of regulatory T cells (Tregs) or injection of in vitro expanded autologous/heterologous Tregs (cellular therapy) can alter the natural history of autoimmune diseases. In this review, we present data from murine and human studies suggesting that 1) glucocorticoid-induced tumor necrosis factor receptor-related protein (GITR) plays a crucial role in thymic Treg (tTreg) differentiation and expansion; 2) GITR plays a crucial role in peripheral Treg (pTreg) expansion; 3) in patients with Sjögren syndrome and systemic lupus erythematosus, CD4(+)GITR(+) pTregs are expanded in patients with milder forms of the disease; and 4) GITR is superior to other cell surface markers to differentiate Tregs from other CD4(+) T cells. In this context, we consider two potential new approaches for treating autoimmune diseases consisting of the in vivo expansion of GITR(+) Tregs by GITR-triggering drugs and in vitro expansion of autologous or heterologous GITR(+) Tregs to be infused in patients. Advantages of such an approach, technical problems, and safety issues are discussed.

Expansion of regulatory GITR+CD25 low/-CD4+ T cells in systemic lupus erythematosus patients

Introduction

CD4⁺CD25^low/-GITR⁺ T lymphocytes expressing forkhead box protein P3 (FoxP3) and showing regulatory activity have been recently described in healthy donors. The objective of the study was to evaluate the proportion of CD4⁺CD25^low/-GITR⁺ T lymphocytes within CD4⁺ T cells and compare their phenotypic and functional profile with that of CD4⁺CD25^highGITR⁻ T lymphocytes in systemic lupus erythematosus (SLE) patients.

Methods

The percentage of CD4⁺CD25^low/-GITR⁺ cells circulating in the peripheral blood (PB) of 32 patients with SLE and 25 healthy controls was evaluated with flow cytometry. CD4⁺CD25^low/-GITR⁺ cells were isolated with magnetic separation, and their phenotype was compared with that of CD4⁺CD25^highGITR⁻ cells. Regulatory activity of both cell subsets was tested in autologous and heterologous co-cultures after purification through a negative sorting strategy.

Results

Results indicated that CD4⁺CD25^low/-GITR⁺ cells are expanded in the PB of 50% of SLE patients. Expansion was observed only in patients with inactive disease. Phenotypic analysis demonstrated that CD4⁺CD25^low/-GITR⁺ cells display regulatory T-cell (Treg) markers, including FoxP3, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), transforming growth factor-beta (TGF-β), and interleukin (IL)-10. In contrast, CD4⁺CD25^highGITR⁻ cells appear to be activated and express low levels of Treg markers. Functional experiments demonstrated that CD4⁺CD25^low/-GITR⁺ cells exert a higher inhibitory activity against both autologous and heterologous cells as compared with CD4⁺CD25^highGITR⁻ cells. Suppression is independent of cell contact and is mediated by IL-10 and TGF-β.

Conclusions

Phenotypic and functional data demonstrate that in SLE patients, CD4⁺CD25^low/-GITR⁺ cells are fully active Treg cells, possibly representing peripheral Treg (pTreg) that are expanded in patients with inactive disease. These data may suggest a key role of this T-cell subset in the modulation of the abnormal immune response in SLE. Strategies aimed at expanding this Treg subset for therapeutic purpose deserve to be investigated.

The changing landscape of type 1 diabetes: recent developments and future frontiers

Type 1 diabetes (T1D) research has made great strides over the past decade with advances in understanding the pathogenesis, natural history, candidate environmental exposures, exposure triggering time, disease prediction, and diagnosis. Major monitoring efforts have provided baseline historical measures, leading to better epidemiological studies incorporating longitudinal biosamples (ie, biobanks), which have allowed for new technologies ('omics') to further expose the etiological agents responsible for the initiation, progression, and eventual clinical onset of T1D. These new frontiers have brought forth high-dimensionality data, which have furthered the evidence of the heterogeneous nature of T1D pathogenesis and allowed for a more mechanistic approach in understanding the etiology of T1D. This review will expand on the most recent advances in the quest for T1D determinants, drawing upon novel research tools that epidemiology, genetics, microbiology, and immunology have provided, linking them to the major hypotheses associated with T1D etiology, and discussing the future frontiers.

Mechanism of BDE209-induced impaired glucose homeostasis based on gene microarray analysis of adult rat liver

Several persistent organic pollutants are reported to be potentially associated with the risk of human diabetes that has become rapidly epidemic in China currently. 2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether (BDE209) is commercially most important both in the production and in the use of polybrominated diphenyl ethers (PBDEs). It might bioaccumulate in wildlife and human and is the only PBDEs mixture still used today. In the present study, male adult rats treated with BDE209 (0, 0.05, 1, and 20 mg/kg) for 8 weeks were used to explore the effects of BDE209 on glucose homeostasis and possible mechanisms; 0.05 mg/kg of BDE209 induced dose-related hyperglycemia. Then, we performed the full-genome gene expression microarrays, gene ontology analysis, and pathway analysis in this group and control. BDE209 induced 1,257 liver gene transcript changes, and 18 canonical pathways were significantly enriched. Four of them were involved in immune diseases, including autoimmune thyroid disease, graft-versus-host disease, allograft rejection, and type I diabetes mellitus (T1MD), which was confirmed by the decrease in serum insulin. Subsequently, gene act network and gene co-expression network found that some MHC molecules and TNF-α were involved in T1DM pathway, which was then confirmed by the increase in serum TNF-α. Additionally, reduced glutathione and superoxide dismutase in plasma indicated that oxidative damage might partly contribute to BDE209-induced hyperglycemia. The results of this study provide some new experimental evidence that the exposure to high levels of BDE209 may contribute to the onset of diabetes in human populations. Further work needs to be done to confirm this link.

Decreased levels of circulating CD4+CD25+Foxp3+ regulatory T cells in patients with primary antiphospholipid syndrome

INTRODUCTION

CD4(+)CD25(+)Foxp3(+) regulatory T (Treg) cell dysfunction has been documented in various autoimmune disorders, but not in antiphospholipid syndrome (APS) so far.

METHODS

In this cross-sectional study, we aim to investigate CD4(+)CD25(+)Foxp3(+) Treg cells, CD3(+)CD19(-) T cells and CD3(-)CD19(+) B cells in patients with primary APS and healthy controls. Cell subtypes were immunophenotyped using specific monoclonal antibodies (anti-CD3 CY5, anti-CD4 FITC, anti-CD25, anti-Foxp3, anti-CD19 PE) and flow cytometry.

RESULTS

Twenty patients with APS and 20 age- and sex-matched controls were studied. The percentage of total lymphocytes, activated Th cells (CD4+CD25+), Treg cells and CD3(-)CD19(+) B cells were found significantly lower in APS patients as compared to controls (all p < 0.05).

CONCLUSION

A dysfunction in CD4(+)CD25(+)Foxp3(+) Treg cells may represent one of the mechanisms leading to autoimmunity in APS patients. The decreased number of CD3(-)CD19(+) B cells of APS patients warrants further elucidation.