Nondepleting anti-CD4 and soluble interleukin-1 receptor prevent autoimmune destruction of syngeneic islet grafts in diabetic NOD mice

The Role of Interleukin-1β in Destruction of Transplanted Islets

Islet transplantation is a promising β-cell replacement therapy for type 1 diabetes, which can reduce glucose lability and hypoglycemic episodes compared with standard insulin therapy. Despite the tremendous progress made in this field, challenges remain in terms of long-term successful transplant outcomes. The insulin independence rate remains low after islet transplantation from one donor pancreas. It has been reported that the islet-related inflammatory response is the main cause of early islet damage and graft loss after transplantation. The production of interleukin-1β (IL-1β) has considered to be one of the primary harmful inflammatory events during pancreatic procurement, islet isolation, and islet transplantation. Evidence suggests that the innate immune response is upregulated through the activity of Toll-like receptors and The NACHT Domain-Leucine-Rich Repeat and PYD-containing Protein 3 inflammasome, which are the starting points for a series of signaling events that drive excessive IL-1β production in islet transplantation. In this review, we show recent contributions to the advancement of knowledge of IL-1β in islet transplantation and discuss several strategies targeting IL-1β for improving islet engraftment.

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.

A phase I study of anti-inflammatory therapy with rilonacept in adolescents and adults with type 1 diabetes mellitus

BACKGROUND

The innate immune system may be activated around the time of diagnosis of type 1 diabetes (T1D). Components of this system, including cytokines such as interleukin-1β (IL-1β) represent potential therapeutic targets for disease modifying therapy.

OBJECTIVE

We conducted a phase 1 trial of rilonacept, an IL-1 cytokine trap, in patients with T1D.

SUBJECTS AND METHODS

Thirteen T1D patients (10 males) with median age (interquartile range, IQR) of 17 years (16-18), a median (IQR) of 5 months (5-7) since diagnosis. Rilonacept was administered subcutaneously for 26 weeks. Incidence of infections was the primary end-point.

RESULTS

There were 85 adverse events; 13 were Grade 2, of which 9 (8 infectious) were judged "possibly related" to the drug. The mean (SD) C-peptide on 2-hour mixed meal tolerance tests decreased from 0.87 (0.42) to 0.59 (0.29) ng/mL (P = .01 by paired t test) during 6 months on treatment. Hemoglobin A1c (HbA1c) increased from 6.8 (1.1) to 7.3 (1.1) (P = .05), but there was not a significant change in daily insulin dose (0.41 ± 0.23 to 0.47 ± 0.18), or in insulin dose-adjusted HbA1c (IDAA1c, 8.4 ± 1.8 to 9.0 ± 1.5). Subjects in "remission," defined as HbA1c <6.5 and a total daily insulin dose <0.5 units/kg/24 h, decreased from 5 to 4. There were no significantly differentially expressed genes in peripheral blood leukocytes before and after rilonacept.

CONCLUSIONS

Rilonacept treatment for 6 months is well-tolerated in individuals with T1D of recent onset, but is unlikely to be efficacious as a single agent in preserving beta cell function.

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.

T Cell-Mediated Beta Cell Destruction: Autoimmunity and Alloimmunity in the Context of Type 1 Diabetes

Type 1 diabetes (T1D) results from destruction of pancreatic beta cells by T cells of the immune system. Despite improvements in insulin analogs and continuous blood glucose level monitoring, there is no cure for T1D, and some individuals develop life-threatening complications. Pancreas and islet transplantation have been attractive therapeutic approaches; however, transplants containing insulin-producing cells are vulnerable to both recurrent autoimmunity and conventional allograft rejection. Current immune suppression treatments subdue the immune system, but not without complications. Ideally a successful approach would target only the destructive immune cells and leave the remaining immune system intact to fight foreign pathogens. This review discusses the autoimmune diabetes disease process, diabetic complications that warrant a transplant, and alloimmunity. First, we describe the current understanding of autoimmune destruction of beta cells including the roles of CD4 and CD8 T cells and several possibilities for antigen-specific tolerance induction. Second, we outline diabetic complications necessitating beta cell replacement. Third, we discuss transplant recognition, potential sources for beta cell replacement, and tolerance-promoting therapies under development. We hypothesize that a better understanding of autoreactive T cell targets during disease pathogenesis and alloimmunity following transplant destruction could enhance attempts to re-establish tolerance to beta cells.

Thinking bedside at the bench: the NOD mouse model of T1DM

Studies over the past 35 years in the nonobese diabetic (NOD) mouse have shown that a number of agents can prevent or even reverse type 1 diabetes mellitus (T1DM); however, these successes have not been replicated in human clinical trials. Although some of these interventions have delayed disease onset or progression in subsets of participants, none have resulted in a complete cure. Even in the most robust responders, the treatments do not permanently preserve insulin secretion or stimulate the proliferation of β cells, as has been observed in mice. The shortfalls of translating NOD mouse studies into the clinic questions the value of using this model in preclinical studies. In this Perspectives, we suggest how immunological and genetic differences between NOD mice and humans might contribute to the differential outcomes and suggest ways in which the mouse model might be modified or applied as a tool to develop treatments and improve understanding of clinical trial outcomes.

Transcriptional and translational regulation of cytokine signaling in inflammatory β-cell dysfunction and apoptosis

Disease is conventionally viewed as the chaotic inappropriate outcome of deranged tissue function resulting from aberrancies in cellular processes. Yet the patho-biology of cellular dysfunction and death encompasses a coordinated network no less sophisticated and regulated than maintenance of homeostatic balance. Cellular demise is far from passive subordination to stress but requires controlled coordination of energy-requiring activities including gene transcription and protein translation that determine the graded transition between defensive mechanisms, cell cycle regulation, dedifferentiation and ultimately to the activation of death programmes. In fact, most stressors stimulate both homeostasis and regeneration on one hand and impairment and destruction on the other, depending on the ambient circumstances. Here we illustrate this bimodal ambiguity in cell response by reviewing recent progress in our understanding of how the pancreatic β cell copes with inflammatory stress by changing gene transcription and protein translation by the differential and interconnected action of reactive oxygen and nitric oxide species, microRNAs and posttranslational protein modifications.

Preliminary studies related to anti-interleukin-1β therapy in children with newly diagnosed type 1 diabetes

BACKGROUND

Interleukin-1β (IL-1β) may play a role in the pathogenesis of type 1 diabetes, but there are no data regarding the efficacy of agents antagonizing IL-1β in patients with this disorder. We characterized the effects of IL-1β on gene expression in peripheral blood mononuclear cells (PBMC) and the clinical and gene expression effects of a short course of recombinant IL-1 receptor antagonist protein, anakinra, on children with newly diagnosed diabetes.

METHODS

PBMC from healthy adult volunteers were exposed to IL-1β for 24 h in vitro. Gene expression was analyzed via microarray. Fifteen children within 1 wk of diagnosis of type 1 diabetes received daily anakinra for 28 d and were followed for 6 months. Blood was drawn for microarray analysis before and after anakinra treatment. Insulin secretory capacity was assessed by mixed-meal tolerance testing (MMTT) at 3-4 wk and 7 months after diagnosis. Hemoglobin A1c (HbA1c) and insulin doses were periodically recorded. Data were compared with two historical control groups of children with newly diagnosed diabetes.

RESULTS

Although in vitro exposure to IL-1β caused many changes in PBMC gene expression, gene expression did not change significantly after anakinra therapy in diabetes patients. Anakinra-treated patients had similar HbA1c and MMTT responses, but lower insulin requirements 1 and 4 months after diagnosis compared to controls, and lower insulin-dose-adjusted A1c 1 month after diagnosis.

CONCLUSIONS

Anakinra therapy is well tolerated in children with newly diagnosed type 1 diabetes. Further studies are needed to demonstrate biological effects.

HE3286, an orally bioavailable synthetic analogue of an active DHEA metabolite suppresses spontaneous autoimmune diabetes in the non-obese diabetic (NOD) mouse

5-Androstene-3β,7β,17β-triol (AET) is a naturally occurring anti-inflammatory adrenal steroid that limits acute and chronic inflammation. HE3286 (17α-ethynyl-5-androstene-3β,7β,17β-triol) is a synthetic derivative of AET with improved pharmaceutical properties and efficacy in some animal models of autoimmunity. Here, daily oral doses of HE3286 led to a suppression of spontaneous autoimmune diabetes in the non-obese diabetic mouse model of type 1 diabetes mellitus when administered either shortly before or after the first incidence of disease onset. Efficacy was associated with reduced insulitis and a suppression of the pathogenic T helper cell type 1 and type 17 phenotypes in peripheral lymphoid organs. These results demonstrate that daily oral treatment with HE3286 administrated relatively late in the destructive autoimmune process led to a suppression of type 1 diabetes mellitus onset and of the pathological inflammatory status, supporting its clinical evaluation in type 1 diabetes mellitus subjects.

Histone deacetylase (HDAC) inhibition as a novel treatment for diabetes mellitus

Both common forms of diabetes have an inflammatory pathogenesis in which immune and metabolic factors converge on interleukin-1β as a key mediator of insulin resistance and β-cell failure. In addition to improving insulin resistance and preventing β-cell inflammatory damage, there is evidence of genetic association between diabetes and histone deacetylases (HDACs); and HDAC inhibitors (HDACi) promote β-cell development, proliferation, differentiation and function and positively affect late diabetic microvascular complications. Here we review this evidence and propose that there is a strong rationale for preclinical studies and clinical trials with the aim of testing the utility of HDACi as a novel therapy for diabetes.

Transgenic expression of single-chain anti-CTLA-4 Fv on beta cells protects nonobese diabetic mice from autoimmune diabetes

T cell-mediated immunodestruction of pancreatic beta cells is the key process responsible for both the development of autoimmune diabetes and the induction of rejection during islet transplantation. In this study, we investigate the hypothesis that transgenic expression of an agonistic, membrane-bound single-chain anti-CTLA-4 Fv (anti-CTLA-4 scFv) on pancreatic beta cells can inhibit autoimmune processes by selectively targeting CTLA-4 on pathogenic T cells. Strikingly, transgenic expression of anti-CTLA-4 scFv on pancreatic beta cells significantly protected NOD mice from spontaneous autoimmune diabetes. Interestingly, local expression of this CTLA-4 agonist did not alter the diabetogenic properties of systemic lymphocytes, because splenocytes from transgenic mice or their nontransgenic littermates equally transferred diabetes in NOD/SCID recipients. By analyzing the T cell development in anti-CTLA-4 scFv/Th1/Th2 triple transgenic mice, we found that beta cell-specific expression of CTLA-4 agonist did not affect the development of Th1/Th2 or CD4(+)CD25(+) regulatory T cells. Most strikingly, islets from transgenic mice inhibited T cell response to immobilized anti-CD3 in a T cell-islet coculture system, suggesting a trans-mediated inhibition provided by transgenic islets. Finally, transgenic islets implanted in diabetic recipients survived much longer than did wild-type islets, indicating a therapeutic potential of this genetically modified islet graft in autoimmune diabetes.

Patients with chronic pancreatitis have islet progenitor cells in their ducts, but reversal of overt diabetes in NOD mice by anti-CD3 shows no evidence for islet regeneration

Monoclonal antibodies to T-cell coreceptors have been shown to tolerise autoreactive T-cells and prevent or even reverse autoimmune pathology. In type 1 diabetes, there is a loss of insulin-secreting beta-cells, and a cure for type 1 diabetes would require not only tolerance induction but also recovery of the functional beta-cell mass. Although we have previously shown that diabetic mice have increased numbers of ductal progenitors in the pancreas, there is no evidence of any increase of insulin-secreting cells in the ducts. In contrast, in the adult human pancreas of patients with chronic pancreatitis, we can demonstrate, in the ducts, increased numbers of insulin-containing cells, as well as cells containing other endocrine and exocrine markers. There are also significantly increased numbers of cells expressing the homeodomain protein, pancreatic duodenal homeobox-1. Anti-CD3 has been shown to reverse overt diabetes in NOD mice; thus, we have used this model to ask whether monoclonal antibody-mediated inhibition of ongoing beta-cell destruction enables islet regeneration to occur. We find no evidence that such monoclonal antibody therapy results in either regeneration of insulin-secreting beta-cells or of increased proliferation of islet beta-cells.

A potent immunomodulatory compound, (S,R)-3-Phenyl-4,5-dihydro-5-isoxazole acetic acid, prevents spontaneous and accelerated forms of autoimmune diabetes in NOD mice and inhibits the immunoinflammatory diabetes induced by multiple low doses of streptozotocin in CBA/H mice

(S,R)-3-Phenyl-4,5-dihydro-5-isoxasole acetic acid (VGX-1027) is an isoxazole compound that exhibits various immunomodulatory properties. The capacity of VGX-1027 to prevent interleukin (IL)-1beta plus interferon-gamma-induced pancreatic islet death in vitro prompted us to evaluate its effects on the development of autoimmune diabetes in preclinical models of human type 1 diabetes mellitus (T1D). Administration of VGX-1027 to NOD mice with spontaneous or accelerated forms of diabetes induced either by injection of cyclophosphamide or by transfer of spleen cells from acutely diabetic syngeneic donors markedly reduced the cumulative incidence of diabetes and insulitis. In addition, VGX-1027 given either i.p. or p.o. to CBA/H mice made diabetic with multiple low doses of streptozotocin successfully counteracted the development of destructive insulitis and hyperglycemia. The animals receiving VGX-1027 exhibited reduced production of the proinflammatory mediators tumor necrosis factor-alpha, IL-1beta, macrophage migration inhibitory factor, and inducible nitric-oxide synthase-mediated nitric oxide generation in both pancreatic islets and peripheral compartments. These results indicate that VGX-1027 probably exerts its antidiabetogenic effects by limiting cytokine-mediated immunoinflammatory events, leading to inflammation and destruction of pancreatic islets. VGX-1027 seems worthy of being considered as a candidate drug in the development of new therapeutic strategies for the prevention and early treatment of T1D.

Islet transplantation: immunological perspectives

Clinical trials of islet transplantation are showing remarkable success, but they require administration of chronic immunosuppression, and are underscoring the large gap that exists between the number of human donors available and the number of patients that could benefit from the procedure. Recent progress has been made in the definition of key immunological mechanisms that are involved in determining islet transplant outcome. Clinical and preclinical studies, and studies in small animal model systems, will all eventually contribute to the definition of efficient and safe protocols for islet transplantation. If the use of xenografts is successful, it might represent a solution to the shortage of human organs.

Effects of streptozotocin on autoimmune diabetes in NOD mice

Non-obese diabetic (NOD) mice develop autoimmunity that destroys their native beta cells causing diabetes. Their autoimmunity will also destroy syngeneic transplanted islets and transfer both autoimmunity and diabetes via spleen cells to non-diabetic mice. In this report, we studied the effects of streptozotocin (STZ) on the autoimmune diabetes in NOD mice. We transplanted NOD.SCID islets into three groups of NOD mice: (1) spontaneously diabetic NOD mice (NOD-sp.); (2) prediabetic NOD mice made diabetic by streptozotocin (NOD-stz); and (3) diabetic NOD mice also treated with streptozotocin (NOD-sp./stz). In the first group, the transplants were rejected within 3 weeks. In the second and third groups, the transplants survived indefinitely. Alloxan, a drug similar to streptozotocin, did not have the same effect as streptozotocin. The ability of streptozotocin to prevent diabetes in young NOD mice was reversed by anti-CD8 antibody treatment but not by anti-CD4 treatment. Streptozotocin also made spleen cells from diabetic NOD mice less effective transferring diabetes. These results indicate that streptozotocin treatment both prevents and reverses the islet destructive autoimmunity in NOD mice. We postulate that the effects of streptozotocin treatment may be mediated in part by regulatory T cells.