Adeno-associated virus vector-mediated IL-10 gene delivery prevents type 1 diabetes in NOD mice

IL-10 modified mRNA monotherapy prolongs survival after composite facial allografting through the induction of mixed chimerism

Vascularized composite allotransplantation has great potential in face transplantation by supporting functional restoration following tissue grafting. However, the need for lifelong administration of immunosuppressive drugs still limits its wide use. Modified mRNA (modRNA) technology provides an efficient and safe method to directly produce protein in vivo. Nevertheless, the use of IL-10 modRNA-based protein replacement, which exhibits anti-inflammatory properties, has not been shown to prolong composite facial allograft survival. In this study, IL-10 modRNA was demonstrated to produce functional IL-10 protein in vitro, which inhibited pro-inflammatory cytokines and in vivo formation of an anti-inflammatory environments. We found that without any immunosuppression, C57BL/6J mice with fully major histocompatibility complex (MHC)-mismatched facial allografts and local injection of IL-10 modRNA had a significantly prolonged survival rate. Decreased lymphocyte infiltration and pro-inflammatory T helper 1 subsets and increased anti-inflammatory regulatory T cells (Tregs) were seen in IL-10 modRNA-treated mice. Moreover, IL-10 modRNA induced multilineage chimerism, especially the development of donor Treg chimerism, which protected allografts from destruction because of recipient alloimmunity. These results support the use of monotherapy based on immunomodulatory IL-10 cytokines encoded by modRNA, which inhibit acute rejection and prolong allograft survival through the induction of donor Treg chimerism.

Effect of IL4 and IL10 on a human in vitro type 1 diabetes model

We defined the effect of the anti-inflammatory cytokines IL4 and IL10 on an in vitro model of human T1D. After preincubation with IL4 or IL10, human islet microtissues were co-cultured with PBMC and proinflammatory cytokines for a few hours or for multiple days to assess acute and chronic effects. This resulted in an immune attack with infiltration of T cells into the islet, a loss of beta cell endocrine function, and an upregulation of HLA-I on the beta cells. HLA-I upregulation was associated with infiltration of T cells and both HLA-I expression and infiltration were associated with impaired insulin secretion. Preincubation with IL4 or IL10 did not preserve beta cell function but decreased infiltration of T cells. Our data support the hypothesis that a loss of beta cell endocrine function mediates an increase in beta cell specific antigen presentation. IL4 and IL10 failed to preserve beta cell endocrine function.

Diabetes mellitus and diabetic foot ulcer: Etiology, biochemical and molecular based treatment strategies via gene and nanotherapy

Diabetes mellitus (DM) is a collection of metabolic and pathophysiological disorders manifested with high glucose levels in the blood due to the inability of β-pancreatic cells to secrete an adequate amount of insulin or insensitivity of insulin towards receptor to oxidize blood glucose. Nevertheless, the preceding definition is only applicable to people who do not have inherited or metabolic disorders. Suppose a person who has been diagnosed with Type 1 or Type 2DM sustains an injury and the treatment of the damage is complicated and prolonged. In that case, the injury is referred to as a diabetic foot ulcer (DFU). In the presence of many proliferating macrophages in the injury site for an extended period causes the damage to worsen and become a diabetic wound. In this review, the scientific information and therapeutic management of DM/DFU with nanomedicine, and other related data were collected (Web of Science and PubMed) from January 2000 to January 2022. Most of the articles revealed that standard drugs are usually prescribed along with hypoglycaemic medications. Conversely, such drugs stabilize the glucose transporters and homeostasis for a limited period, resulting in side effects such as kidney damage/failure, absorption/gastrointestinal problems, and hypoglycemic issues. In this paper, we review the current basic and clinical evidence about the potential of medicinal plants, gene therapy, chemical/green synthesized nanoparticles to improving the metabolic profile, and facilitating the DM and DFU associated complications. Preclinical studies also reported lower plasma glucose with molecular targets in DM and DFU. Research is underway to explore chemical/green synthesized nanoparticle-based medications to avoid such side effects. Hence, the present review is intended to address the current challenges, recently recognized factors responsible for DM and DFU, their pathophysiology, insulin receptors associated with DM, medications in trend, and related complications.

Rational Design of Immunomodulatory Hydrogels for Chronic Wound Healing

With all the advances in tissue engineering for construction of fully functional skin tissue, complete regeneration of chronic wounds is still challenging. Since immune reaction to the tissue damage is critical in regulating both the quality and duration of chronic wound healing cascade, strategies to modulate the immune system are of importance. Generally, in response to an injury, macrophages switch from pro-inflammatory to an anti-inflammatory phenotype. Therefore, controlling macrophages' polarization has become an appealing approach in regenerative medicine. Recently, hydrogels-based constructs, incorporated with various cellular and molecular signals, have been developed and utilized to adjust immune cell functions in various stages of wound healing. Here, the current state of knowledge on immune cell functions during skin tissue regeneration is first discussed. Recent advanced technologies used to design immunomodulatory hydrogels for controlling macrophages' polarization are then summarized. Rational design of hydrogels for providing controlled immune stimulation via hydrogel chemistry and surface modification, as well as incorporation of cell and molecules, are also dicussed. In addition, the effects of hydrogels' properties on immunogenic features and the wound healing process are summarized. Finally, future directions and upcoming research strategies to control immune responses during chronic wound healing are highlighted.

Lactobacilli and bifidobacteria derived from infant intestines may activate macrophages and lead to different IL-10 secretion

In this study, three strains of lactobacilli and bifidobacteria originally isolated from healthy infants, were tested for their abilities to activate RAW264.7 cells. Gene expression and cytokine production of interleukin-10 (IL-10) of RAW264.7 cells were evaluated. The activation of extracellular regulated protein kinases 1/2 (ERK1/2), p38, and nuclear factor-κB (NK-κB) were also assessed. These results suggest lactobacilli and bifidobacteria in infants may promote production of IL-10 in macrophages, conferring a protective effect in hosts suffering from inflammation. Dimerization of TLR2 and MyD88 and subsequent phosphorylation of the key downstream signaling molecules, such as MAPKs and NK-κB, may be one of the key underlying mechanisms of activation of macrophages by these microbes. Bifidobacteria and lactobacilli induced macrophages to secrete IL-10 in a different manner, which may relate to their abilities to activate key signaling pathways mediated by TLR2 and MyD88.

Using a barcoded AAV capsid library to select for clinically relevant gene therapy vectors

While gene transfer using recombinant adeno-associated viral (rAAV) vectors has shown success in some clinical trials, there remain many tissues that are not well transduced. Because of the recent success in reprogramming islet-derived cells into functional β cells in animal models, we constructed 2 highly complex barcoded replication competent capsid shuffled libraries and selected for high-transducing variants on primary human islets. We describe the generation of a chimeric AAV capsid (AAV-KP1) that facilitates transduction of primary human islet cells and human embryonic stem cell-derived β cells with up to 10-fold higher efficiency compared with previously studied best-in-class AAV vectors. Remarkably, this chimeric capsid also enabled transduction of both mouse and human hepatocytes at very high levels in a humanized chimeric mouse model, thus providing a versatile vector that has the potential to be used in both preclinical testing and human clinical trials for liver-based diseases and diabetes.

Regulated hAAT Expression from a Novel rAAV Vector and Its Application in the Prevention of Type 1 Diabetes

We, and others, have previously achieved high and sustained levels of transgene expression from viral vectors, such as recombinant adeno-associated virus (rAAV). However, regulatable transgene expression may be preferred in gene therapy for diseases, such as type 1 diabetes (T1D) and rheumatoid arthritis (RA), in which the timing and dosing of the therapeutic gene product play critical roles. In the present study, we generated a positive feedback regulation system for human alpha 1 antitrypsin (hAAT) expression in the rAAV vector. We performed quantitative kinetics studies in vitro and in vivo demonstrating that this vector system can mediate high levels of inducible transgene expression. Transgene induction could be tailored to occur rapidly or gradually, depending on the dose of the inducing drug, doxycycline (Dox). Conversely, after withdrawal of Dox, the silencing of transgene expression occurred slowly over the course of several weeks. Importantly, rAAV delivery of inducible hAAT significantly prevented T1D development in non-obese diabetic (NOD) mice. These results indicate that this Dox-inducible vector system may facilitate the fine-tuning of transgene expression, particularly for hAAT treatment of human autoimmune diseases, including T1D.

Alpha-1 Antitrypsin Therapy for Autoimmune Disorders

Autoimmune diseases are conditions caused by an over reactive immune system that attacks self-tissues and organs. Although the pathogenesis of autoimmune disease is complex and multi-factorial, inflammation is commonly involved. Therefore, anti-inflammatory therapies hold potential for the treatment of autoimmune diseases. However, long-term control of inflammation is challenging and most of the currently used drugs have side effects. Alpha-1 antitrypsin (AAT) is an anti-inflammatory protein with a well-known safety profile. The therapeutic potential of AAT has been tested in several autoimmune disease models. The first study using a recombinant adeno-associated viral (rAAV) vector showed that AAT gene transfer prevented the development of type 1 diabetes (T1D) in the non-obese diabetic (NOD) mouse model. Subsequent studies showed that treatment with AAT protein prevented and reversed type 1 diabetes. The beneficial effects of AAT treatment have also been observed in other autoimmune disease models such as rheumatoid arthritis and systemic lupus erythematosus. This paper reviews the therapeutic application of AAT and discusses possible mechanisms of action in various autoimmune diseases.

Gene therapy and type 1 diabetes mellitus

BACKGROUND

Type 1 diabetes mellitus (T1DM) is an autoimmune disorder characterized by T cell-mediated self-destruction of insulin-secreting islet β cells. Management of T1DM is challenging and complicated especially with conventional medications. Gene therapy has emerged as one of the potential therapeutic alternatives to treat T1DM. This review primarily focuses on the current status and the future perspectives of gene therapy in the management of T1DM. A vast number of the studies which are reported on gene therapy for the management of T1DM are done in animal models and in preclinical studies. In addition, the safety of such therapies is yet to be established in humans. Currently, there are several gene level interventions that are being investigated, notably, overexpression of genes and proteins needed against T1DM, transplantation of cells that express the genes against T1DM, stem-cells mediated gene therapy, genetic vaccination, immunological precursor cell-mediated gene therapy and vectors.

METHODS

We searched the current literature through searchable online databases, journals and other library sources using relevant keywords and search parameters. Only relevant publications in English, between the years 2000 and 2018, with evidences and proper citations, were considered. The publications were then analyzed and segregated into several subtopics based on common words and content. A total of 126 studies were found suitable for this review.

FINDINGS

Generally, the pros and cons of each of the gene-based therapies have been discussed based on the results collected from the literature. However, there are certain interventions that require further detailed studies to ensure their effectiveness. We have also highlighted the future direction and perspectives in gene therapy, which, researchers could benefit from.

Identification of Functional Genetic Polymorphisms at IL-10 Promoter Region and their Association with Risk of Ischemic Stroke in Chinese Han Population

BACKGROUND

Pleiotropic cytokine interleukin-10 (IL-10) has been suggested as modifying risk for atherosclerosis. Promoter region genetic polymorphism of IL-10 gene is known to be associated with the level of IL-10 production. Through these effects, they might be involved with the ischemic stroke (IS). Our aim was to assess the nature of the functional polymorphisms in IL-10 promoter and any links with IS in Chinese Han population.

METHODS

The IL-10 -1082 G>A, -819 C>T and -592 C>A functional polymorphisms were determined by TaqMan SNP Genotyping assays in 1296 subjects (648 IS patients diagnosed by CTs or/and magnetic resonance imaging (MRI) and 648 normal healthy controls from Chinese Han Population). Multivariate logistic regression analysis was used to show the association between the IL-10 genotypes and the IS events.

RESULTS

We found that the CC genotype of -819 C>T was more common in controls than IS subjects (P<0.05, corrected for multiple testing) in the Han population. CC carriage may be associated with the decreased risk of IS in the Han ethnic group (OR 0.65, 95% CI 0.43-0.97). In addition, the CC genotype in -592 C>A and GG genotype in -1082 G>A are all extremely low in Chinese Han cases and controls.

CONCLUSIONS

The G allele frequency at the -1082 promoter region of IL-10 was rare in Chinese Han population which are diffierent from American/European populations.. IL-10 -819 C>T may be an independent protective factor for IS in the Chinese Han population.

Immunomodulation by helminths: Similar impact on type 1 and type 2 diabetes?

The incidence of both type 1 (T1D) and type 2 diabetes (T2D) is drastically increasing, and it is predicted that the global prevalence of diabetes will reach almost 600 million cases by 2035. Even though the pathogenesis of both types of diabetes is distinct, the immune system is actively involved in both forms of the disease. Genetic and environmental factors determine the risk to develop T1D. On the other hand, sedentary life style, surplus of food intake and other lifestyle changes contribute to the increase of T2D incidence. Improved sanitation with high-quality medical treatment is such an environmental factor that has led to a continuous reduction of infectious diseases including helminth infections over the past decades. Recently, a growing body of evidence has implicated a negative association between helminth infections and diabetes in humans as well as animal models. In this review, we discuss studies that have provided evidence for the beneficial impact of helminth infections on T1D and T2D. Possible mechanisms are presented by which helminths prevent T1D onset by mitigating pancreatic inflammation and confer protection against T2D by improving insulin sensitivity, alleviating inflammation, augmenting browning of adipose tissue and improving lipid metabolism and insulin signalling.

Highly efficient adenoviral transduction of pancreatic islets using a microfluidic device

Tissues are challenging to genetically manipulate due to limited penetration of viral particles resulting in low transduction efficiency. We are particularly interested in expressing genetically-encoded sensors in ex vivo pancreatic islets to measure glucose-stimulated metabolism, however poor viral penetration biases these measurements to only a subset of cells at the periphery. To increase mass transfer of viral particles, we designed a microfluidic device that holds islets in parallel hydrodynamic traps connected by an expanding by-pass channel. We modeled viral particle flow into the tissue using fluorescently-labelled gold nanoparticles of varying sizes and showed a penetration threshold of only ∼5 nm. To increase this threshold, we used EDTA to transiently reduce cell-cell adhesion and expand intercellular space. Ultimately, a combination of media flow and ETDA treatment significantly increased adenoviral transduction to the core of the islet. As proof-of-principle, we used this protocol to transduce an ER-targeted redox sensitive sensor (eroGFP), and revealed significantly greater ER redox capacity at core islet cells. Overall, these data demonstrate a robust method to enhance transduction efficiency of islets, and potentially other tissues, by using a combination of microfluidic flow and transient tissue expansion.

A combination hydrogel microparticle-based vaccine prevents type 1 diabetes in non-obese diabetic mice

Targeted delivery of self-antigens to the immune system in a mode that stimulates a tolerance-inducing pathway has proven difficult. To address this hurdle, we developed a vaccine based-approach comprised of two synthetic controlled-release biomaterials, poly(lactide-co-glycolide; PLGA) microparticles (MPs) encapsulating denatured insulin (key self-antigen in type 1 diabetes; T1D), and PuraMatrix^TM peptide hydrogel containing granulocyte macrophage colony-stimulating factor (GM-CSF) and CpG ODN1826 (CpG), which were included as vaccine adjuvants to recruit and activate immune cells. Although CpG is normally considered pro-inflammatory, it also has anti-inflammatory effects, including enhancing IL-10 production. Three subcutaneous administrations of this hydrogel (GM-CSF/CpG)/insulin-MP vaccine protected 40% of NOD mice from T1D. In contrast, all control mice became diabetic. In vitro studies indicate CpG stimulation increased IL-10 production, as a potential mechanism. Multiple subcutaneous injections of the insulin containing formulation resulted in formation of granulomas, which resolved by 28 weeks. Histological analysis of these granulomas indicated infiltration of a diverse cadre of immune cells, with characteristics reminiscent of a tertiary lymphoid organ, suggesting the creation of a microenvironment to recruit and educate immune cells. These results demonstrate the feasibility of this injectable hydrogel/MP based vaccine system to prevent T1D.

Controlled release strategies for modulating immune responses to promote tissue regeneration

Advances in the field of tissue engineering have enhanced the potential of regenerative medicine, yet the efficacy of these strategies remains incomplete, and is limited by the innate and adaptive immune responses. The immune response associated with injury or disease combined with that mounted to biomaterials, transplanted cells, proteins, and gene therapies vectors can contribute to the inability to fully restore tissue function. Blocking immune responses such as with anti-inflammatory or immunosuppressive agents are either ineffective, as the immune response contributes significantly to regeneration, or have significant side effects. This review describes targeted strategies to modulate the immune response in order to limit tissue damage following injury, promote an anti-inflammatory environment that leads to regeneration, and induce antigen (Ag)-specific tolerance that can target degenerative diseases that destroy tissues and promote engraftment of transplanted cells. Focusing on targeted immuno-modulation, we describe local delivery techniques to sites of inflammation as well as systemic approaches that preferentially target subsets of immune populations.

Interleukin 10-coated nanoparticle systems compared for molecular imaging of atherosclerotic lesions

Atherosclerosis (AS) is one of the leading causes of mortality in high-income countries. Early diagnosis of vulnerable atherosclerotic lesions is one of the biggest challenges currently facing cardiovascular medicine. The present study focuses on developing targeted nanoparticles (NPs) in order to improve the detection of vulnerable atherosclerotic-plaques. Various biomarkers involved in the pathogenesis of atherosclerotic-plaques have been identified and one of these promising candidates for diagnostic targeting is interleukin 10 (IL10). IL10 has been shown to be a key anti-inflammatory responding cytokine in the early stages of atherogenesis, and has already been used for therapeutic interventions in humans and mice. IL10, the targeting sequence, was coupled to two different types of NPs: protamine-oligonucleotide NPs (proticles) and sterically stabilized liposomes in order to address the question of whether the recognition and detection of atherosclerotic-lesions is primarily determined by the targeting sequence itself, or whether it depends on the NP carrier system to which the biomarker is coupled. Each IL10-targeted NP was assessed based on its sensitivity and selectivity toward characterizing atherosclerotic-plaque lesions using an apolipoprotein E-deficient mouse as the model of atherosclerosis. Aortas from apolipoprotein E-deficient mice fed a high fat diet, were stained with either fluorescence-labeled IL10 or IL10-coupled NPs. Ex vivo imaging was performed using confocal laser-scanning microscopy. We found that IL10-targeted proticles generated a stronger signal by accumulating at the surface of atherosclerotic-plaques, while IL10-targeted, sterically stabilized liposomes showed a staining pattern deeper in the plaque compared to the fluorescence-labeled IL10 alone. Our results point to a promising route for enhanced in vivo imaging using IL10-targeted NPs. NPs allow a higher payload of signal emitting molecules to be delivered to the atherosclerotic-plaques, thus improving signal detection. Importantly, this allows for the opportunity to visualize different areas within the plaque scenario, depending on the nature of the applied nanocarrier.

Inducing immune tolerance: a focus on Type 1 diabetes mellitus

Tolerogenic strategies that specifically target diabetogenic immune cells in the absence of complications of immunosuppression are the desired treatment for the prevention or even reversal of Type 1 diabetes (T1D). Antigen (Ag)-based therapies must not only suppress disease-initiating diabetogenic T cells that are already activated, but, more importantly, prevent activation of naive auto-Ag-specific T cells that may become autoreactive through epitope spreading as a result of Ag liberation from damaged islet cells. Therefore, identification of auto-Ags relevant to T1D initiation and progression is critical to the design of effective Ag-specific therapies. Animal models of T1D have been successfully employed to identify potential diabetogenic Ags, and have further facilitated translation of Ag-specific tolerance strategies into human clinical trials. In this review, we highlight important advances using animal models in Ag-specific T1D immunotherapies, and the application of the preclinical findings to human subjects. We provide an up-to-date overview of the strengths and weaknesses of various tolerance-inducing strategies, including infusion of soluble Ags/peptides by various routes of delivery, genetic vaccinations, cell- and inert particle-based tolerogenic approaches, and various other strategies that target distinct tolerance-inducing pathways.

Dietary flavonol epicatechin prevents the onset of type 1 diabetes in nonobese diabetic mice

Type 1 diabetes (T1D) is an autoimmune disease characterized by the selective destruction of pancreatic β-cells. Although successful islet transplantation provides a promising treatment, high cost, lack of donor organs, immune-mediated destruction of transplanted islets, and side effects from immunosuppressive drugs greatly limit its uses. Therefore, the search for novel and cost-effective agents that can prevent or ameliorate T1D is extremely important to decrease the burden of T1D. In this study, we discovered that epicatechin (EC, 0.5% in drinking water), a flavonol primarily in cocoa, effectively prevented T1D in nonobese diabetic (NOD) mice. At 32 weeks of age, 66.7% of control mice had overt diabetes, whereas only 16.6% of EC-treated mice became diabetic. Consistently, EC mice had significantly higher plasma insulin levels but lower glycosylated hemoglobin concentrations compared to control mice. EC had no significant effects on food or water intake and body weight gain in NOD mice, suggesting that EC's effect was not due to alterations in these variables. Treatment with EC elevates circulating anti-inflammatory cytokine interleukin-10 levels, ameliorates pancreatic insulitis, and improves pancreatic islet mass. These findings demonstrate that EC may be a novel, plant-derived compound capable of preventing T1D by modulating immune function and thereby preserving islet mass.

Optimal formation of genetically modified and functional pancreatic islet spheroids by using hanging-drop strategy

BACKGROUND

Rejection and hypoxia are important factors causing islet loss at an early stage after pancreatic islet transplantation. Recently, islets have been dissociated into single cells for reaggregation into so-called islet spheroids. Herein, we used a hanging-drop strategy to form islet spheroids to achieve functional equivalence to intact islets.

METHODS

To obtain single islet cells, we dissociated islets with trypsin-EDTA digestion for 10 minutes. To obtain spheroids, we dropped various numbers of single cells (125, 250, or 500 cells/30 μL drop) onto a Petri dish, that was inverted for incubation in humidified air containing 5% CO(2) at 37 °C for 7 days. The aggregated spheroids in the droplets were harvested for further culture.

RESULTS

The size of the aggregated islet spheroids depended on the number of single cells (125-500 cells/30 μL droplet). Their morphology was similar to that of intact islets without any cellular damage. When treated with various concentrations of glucose to evaluate responsiveness, their glucose-mediated stimulation index value was similar to that of intact islets, an observation that was attributed to strong cell-to-cell interactions in islet spheroids. However, islet spheroids aggregated in general culture dishes showed abnormal glucose responsiveness owing to weak cell-to-cell interactions. Cell-to-cell interactions in islet spheroids were confirmed with an anti-connexin-36 monoclonal antibody. Finally, nonviral poly(ethylene imine)-mediated interleukin-10 cytokine gene delivered beforehand into dissociated single cells before formation of islet spheroids increased the gene transfection efficacy and interleukin-10 secretion from islet spheroids >4-fold compared with intact islets.

CONCLUSION

These results demonstrated the potential application of genetically modified, functional islet spheroids with of controlled size and morphology using an hanging-drop technique.

Interleukin-10: an anti-inflammatory marker to target atherosclerotic lesions via PEGylated liposomes

Atherosclerosis (AS) causes cardiovascular disease, which leads to fatal clinical end points like myocardial infarction or stroke, the most prevalent causes of death in developed countries. An early, noninvasive method of detection and diagnosis of atherosclerotic lesions is necessary to prevent and treat these clinical end points. Working toward this goal, we examined recombinant interleukin-10 (IL-10), stealth liposomes with nanocargo potency for NMRI relevant contrast agents, and IL-10 coupled to stealth liposomes in an ApoE-deficient mouse model using confocal laser-scanning microscopy (CLSM). Through ex vivo incubation and imaging with CLSM, we showed that fluorescently labeled IL-10 is internalized by AS plaques, and a low signal is detected in both the less injured aortic surfaces and the arteries of wild-type mice. In vivo experiments included intravenous injections of (i) fluorescent IL-10, (ii) IL-10 targeted carboxyfluorescin (CF-) labeled stealth liposomes, and (iii) untargeted CF-labeled stealth liposomes. Twenty-four hours after injection the arteries were dissected and imaged ex vivo. Compared to free IL-10, we observed a markedly stronger fluorescence intensity with IL-10 targeted liposomes at AS plaque regions. Moreover, untargeted CF-labeled liposomes showed only weak, unspecific binding. Neither free IL-10 nor IL-10 targeted liposomes showed significant immune reaction when injected into wild-type mice. Thus, the combined use of specific anti-inflammatory proteins, high payloads of contrast agents, and liposome particles should enable current imaging techniques to better recognize and visualize AS plaques for research and prospective therapeutic strategies.

Identification of adeno-associated viral vectors suitable for intestinal gene delivery and modulation of experimental colitis

Effective gene transfer with sustained gene expression is an important adjunct to the study of intestinal inflammation and future therapy in inflammatory bowel disease. Recombinant adeno-associated virus (AAV) vectors are ideal for gene transfer and long-term transgene expression. The purpose of our study was to identify optimal AAV pseudotypes for transduction of the epithelium in the small intestine and colon, which could be used for studies in experimental colitis. The tropism and transduction efficiencies of AAV pseudotypes 1-10 were examined in murine small intestine and colon 8 wk after administration by real-time PCR and immunohistochemistry. The clinical and histopathological effects of IL-10-mediated intestinal transduction delivered by AAVrh10 were examined in the murine IL-10⁻/⁻ enterocolitis model. Serum IL-10 levels and IL-10 expression were followed by ELISA and real-time PCR, respectively. AAV pseudotypes 4, 7, 8, 9, and 10 demonstrated optimal intestinal transduction. Transgene expression was sustained 8 wk after administration and was frequently observed in enteroendocrine cells. Long-term IL-10 gene expression and serum IL-10 levels were observed following AAV transduction in an IL-10-/- model of enterocolitis. Animals treated with AAVrh10-IL-10 had lower disease activity index scores, higher colon weight-to-length ratios, and lower microscopic inflammation scores. This study identifies novel AAV pseudotypes with small intestine and colon tropism and sustained transgene expression capable of modulating mucosal inflammation in a murine model of enterocolitis.

Tissue engineering tools for modulation of the immune response

Tissue engineering scaffolds have emerged as a powerful tool within regenerative medicine. These materials are being designed to create environments that promote regeneration through a combination of: (i) scaffold architecture, (ii) the use of scaffolds as vehicles for transplanting progenitor cells, and/or (iii) localized delivery of inductive factors or genes encoding for these inductive factors. This review describes the techniques associated with each of these components. Additionally, the immune response is increasingly recognized as a factor influencing regeneration. The immune reaction to an implant begins with an acute response to the injury and innate recognition of foreign materials, with the subsequent chronic immune response involving specific recognition of antigens (e.g., transplanted cells) by the adaptive immune response, which can eventually lead to rejection of the implant. Thus, we also describe the impact of each component on the immune response, and strategies (e.g., material design, anti-inflammatory cytokine delivery, and immune cell recruitment/transplantation) to modulate, yet not eliminate, the local immune response in order to promote regeneration, which represents another important tool for regenerative medicine.

Reprogramming gut and pancreas endocrine cells to treat diabetes

Multiple approaches have been investigated with the ultimate goal of providing insulin independence to patients with either type 1 or type 2 diabetes. Approaches to produce insulin-secreting cells in culture, convert non-β-cells into functional β-cells or engineer autologous cells to express and secrete insulin in a meal-responsive manner have all been described. This research has been facilitated by significant improvements in both viral and non-viral gene delivery approaches that have enabled new experimental strategies. Many studies have examined possible avenues to confer islet cytoprotection against immune rejection, inflammation and apoptosis by genetic manipulation of islet cells prior to islet transplantation. Here we review several reports based on the reprogramming of pancreas and gut endocrine cells to treat diabetes.

Immunomodulation and regeneration of islet Beta cells by cytokines in autoimmune type 1 diabetes

Juvenile or type 1 diabetes (T1D) involves autoimmune-mediated destruction of insulin-producing β cells in the islets of Langerhans in the pancreas. Lack of insulin prevents the absorption and metabolism of glucose throughout the body by interfering with cell signaling. Cytokines have been shown to play a key role in β cell destruction and regulation of autoimmunity in T1D. The multiple roles of cytokines in T1D pathogenesis, regulation, and regeneration of β cells presents both promise and challenge for their use in immunotherapy. We found that mycobacterial adjuvants induce various regulatory T cells in the non-obese diabetic (NOD) mouse model of T1D. Cytokines produced by these cells not only regulate innate and adaptive immunity but also prevent the development of diabetes and partially restored normoglycemia in diabetic NOD mice. We discovered that adjuvant immunotherapy upregulated Regenerating (Reg) genes in the islets and induced interleukin 22 (IL-22)-producing Th17 cells. IL-22 is known to upregulate Reg gene expression in islets and could potentially induce regeneration of β cells and prevent their apoptosis. Therefore, cytokines both induce and regulate T1D and have the potential to regenerate and preserve insulin-producing β cells in the islets.

Effect of acyl chain length and unsaturation on physicochemical properties and transfection efficiency of N-acyl-substituted low-molecular-weight chitosan

The effects of acyl chain length and unsaturation on physicochemical characteristics and transfection efficiency of novel nanomicelles of N-acyl-substituted low-molecular-weight chitosan (N-acyl LMWC) were studied. After transfection optimization, 18-carbon chain length grafts were selected, and N-acyl LMWCs were prepared with increasing unsaturation (18:1-18:3 carbon acyl grafts). N-acyl LMWCs were characterized using infrared spectroscopy and elemental analysis. The effect of DNA addition on size and zeta potential of N-acyl LMWCs was determined by dynamic light scattering. N-acyl LMWC-plasmid DNA (pDNA) polyplex stability was confirmed using gel electrophoresis. Transfection efficiency of the derivative polymers was visualized in human embryonic kidney cells using a plasmid encoding green fluorescent protein by confocal fluorescence microscopy and was quantified using therapeutic plasmids encoding for interleukin-4 and interleukin-10. N-acyl LMWCs could form cationic nanomicelles with average hydrodynamic size between 73 and 132 nm. DNA addition to nanomicelles led to minimal increase in the size. N-acyl LMWC-pDNA polyplexes showed excellent stability on storage and could protect DNA from enzymatic degradation. The transfection efficiencies of N-acyl LMWCs with 18:1 and 18:2 grafts were comparable with FuGENE® HD but were approximately eightfold and 35-fold greater as compared with LMWC and naked DNA, respectively.

Recombinant adeno-associated virus-mediated gene transfer for the potential therapy of adenosine deaminase-deficient severe combined immune deficiency

Severe combined immune deficiency due to adenosine deaminase (ADA) deficiency is a rare, potentially fatal pediatric disease, which results from mutations within the ADA gene, leading to metabolic abnormalities and ultimately profound immunologic and nonimmunologic defects. In this study, recombinant adeno-associated virus (rAAV) vectors based on serotypes 1 and 9 were used to deliver a secretory version of the human ADA (hADA) gene to various tissues to promote immune reconstitution following enzyme expression in a mouse model of ADA deficiency. Here, we report that a single-stranded rAAV vector, pTR2-CB-Igκ-hADA, (1) facilitated successful gene delivery to multiple tissues, including heart, skeletal muscle, and kidney, (2) promoted ectopic expression of hADA, and (3) allowed enhanced serum-based enzyme activity over time. Moreover, the rAAV-hADA vector packaged in serotype 9 capsid drove partial, prolonged, and progressive immune reconstitution in ADA-deficient mice. Overview Summary Gene therapies for severe combined immune deficiency due to adenosine deaminase (ADA) deficiency (ADA-SCID) over two decades have exclusively involved retroviral vectors targeted to lymphocytes and hematopoietic progenitor cells. These groundbreaking gene therapies represented an unprecedented revolution in clinical medicine but in most cases did not fully correct the immune deficiency and came with the potential risk of insertional mutagenesis. Alternatively, recombinant adeno-associated virus (rAAV) vectors have gained attention as valuable tools for gene transfer, having demonstrated no pathogenicity in humans, minimal immunogenicity, long-term efficacy, ease of administration, and broad tissue tropism (Muzyczka, 1992 ; Flotte et al., 1993 ; Kessler et al., 1996 ; McCown et al., 1996 ; Lipkowitz et al., 1999 ; Marshall, 2001 ; Chen et al., 2003 ; Conlon and Flotte, 2004 ; Griffey et al., 2005 ; Pacak et al., 2006 ; Stone et al., 2008 ; Liu et al., 2009 ; Choi et al., 2010 ). Currently, rAAV vectors are being utilized in phase I/II clinical trials for cystic fibrosis, α-1 antitrypsin deficiency, Canavan's disease, Parkinson's disease, hemophilia, limb-girdle muscular dystrophy, arthritis, Batten's disease, and Leber's congenital amaurosis (Flotte et al., 1996 , 2004 ; Kay et al., 2000 ; Aitken et al., 2001 ; Wagner et al., 2002 ; Manno et al., 2003 ; Snyder and Francis, 2005 ; Maguire et al., 2008 ; Cideciyan et al., 2009 ). In this study, we present preclinical data to support the viability of an rAAV-based gene transfer strategy for cure of ADA-SCID. We report efficient transduction of a variety of postmitotic target tissues in vivo, subsequent human ADA (hADA) expression, and enhanced hADA secretion in tissues and blood, with increasing peripheral lymphocyte populations over time.

The role of antigen presenting cells in multiple sclerosis

Multiple sclerosis (MS) is a debilitating T cell mediated autoimmune disease of the central nervous system (CNS). Animal models of MS, such as experimental autoimmune encephalomyelitis (EAE) and Theiler's murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD) have given light to cellular mechanisms involved in the initiation and progression of this organ-specific autoimmune disease. Within the CNS, antigen presenting cells (APC) such as microglia and astrocytes participate as first line defenders against infections or inflammation. However, during chronic inflammation they can participate in perpetuating the self-destructive environment by secretion of inflammatory factors and/or presentation of myelin epitopes to autoreactive T cells. Dendritic cells (DC) are also participants in the presentation of antigen to T cells, even within the CNS. While the APCs alone are not solely responsible for mediating the destruction to the myelin sheath, they are critical players in perpetuating the inflammatory milieu. This review will highlight relevant studies which have provided insight to the roles played by microglia, DCs and astrocytes in the context of CNS autoimmunity.

Genetic vaccination for re-establishing T-cell tolerance in type 1 diabetes

Type 1 diabetes (T1D) is a T-cell mediated autoimmune disease resulting in the destruction of the insulin-secreting β cells. Currently, there is no established clinical approach to effectively suppress long-term the diabetogenic response. Genetic-based vaccination offers a general strategy to reestablish β-cell specific tolerance within the T-cell compartment. The transfer of genes encoding β-cell autoantigens, anti-inflammatory cytokines and/or immunomodulatory proteins has proven to be effective at preventing and suppressing the diabetogenic response in animal models of T1D. The current review will discuss genetic approaches to prevent and treat T1D with an emphasis on plasmid DNA- and adeno-associated virus-based vaccines.

Epigallocatechin gallate delays the onset of type 1 diabetes in spontaneous non-obese diabetic mice

Type 1 diabetes (T1D) results from the autoimmune-mediated destruction of pancreatic β-cells, leading to deficiency of insulin production. Successful islet transplantation can normalise hyperglycaemia in T1D patients; however, the limited availability of the islets, loss of islet cell mass through apoptosis after islet isolation and potential autoimmune destruction of the transplanted islets prevent the widespread use of this procedure. Therefore, the search for novel and cost-effective agents that can prevent or treat T1D is extremely important to decrease the burden of morbidity from this disease. In the present study, we discovered that ( - )-epigallocatechin gallate (EGCG, 0·05 % in drinking-water), the primary polyphenolic component in green tea, effectively delayed the onset of T1D in non-obese diabetic (NOD) mice. At 32 weeks of age, eight (66·7 %) out of twelve mice in the control group developed diabetes, whereas only three (25 %) out of twelve mice in the EGCG-treated group became diabetic (P < 0·05). Consistently, mice supplemented with EGCG had significantly higher plasma insulin levels and survival rate but lower glycosylated Hb concentrations compared with the control animals. EGCG had no significant effects on food or water intake and body weight in mice, suggesting that the glucose-lowering effect was not due to an alteration in these parameters. While EGCG did not modulate insulitis, it elevated the circulating anti-inflammatory cytokine IL-10 level in NOD mice. These findings demonstrate that EGCG may be a novel, plant-derived compound capable of reducing the risk of T1D.

Autoantigens plus interleukin-10 suppress diabetes autoimmunity

BACKGROUND

Recombinant vaccinia virus (rVV) strains expressing the immunomodulatory cholera toxin B subunit (CTB) fused to the autoantigen glutamic acid decarboxylase (GAD) or the immunosuppressive cytokine interleukin-10 (IL-10) were independently able to generate only low levels of immune suppression of type 1 diabetes mellitus (T1DM). Here we suggest that a vaccinia virus (VV)-mediated combination of CTB::GAD fusion and IL-10 proteins promises a effective and durable immunotherapeutic strategy for T1DM.

METHODS

To explore this hypothesis, a CTB::GAD fusion gene was co-delivered with a gene encoding IL-10 by rVV infection (rVV-CTB::GAD + rVV-IL10) into 5-7-week-old non-obese diabetic (NOD) mice. The mice were assessed for vaccine protection against development of hyperglycemia from 12 to 64 weeks of age by assessment of pancreatic inflammation (insulitis) and splenocyte-secreted interferon-gamma and IL-10 cytokine levels.

RESULTS

By 36 weeks of age, from 54% to 80% of the mice in the negative control animal groups (either mock-infected or inoculated with unrelated plasmid or VV) had developed hyperglycemia. Similarly, no statistically significant improvement in protection against diabetes onset was achieved by inoculation with VV expressing CTB::GAD or IL-10 independently. Surprisingly, only 20% of mice co-inoculated with rVV-CTB::GAD + rVV-IL10 developed hyperglycemia by 28 weeks of age. Other treatment groups developed hyperglycemia by 32-36 weeks. After 36 weeks, diabetes incidence no longer increased in any groups until the end of experiment at 64 weeks of age. Histological analysis of pancreatic tissues of hyperglycemic mice revealed high levels of intra-islet insulitis. Analysis of insulitis at termination of the experiment showed that euglycemic mice co-inoculated with VV expressing CTB::GAD and IL-10 had more effectively reduced inflammation in comparison with the other groups.

CONCLUSIONS

A combinatorial vaccination strategy based on VV co-delivery of genes encoding the immunoenhanced autoantigen CTB::GAD and the anti-inflammatory cytokine IL-10 can maintain effective and durable euglycemia and immunological homeostasis in NOD mice with prediabetes.

Recombinant adenoviral expression of IL-10 protects beta cell from impairment induced by pro-inflammatory cytokine

Interleukin-10 (IL-10) is a pleiotropic immunosuppressive and immunostimulatory cytokine. In autoimmune diabetes of the nonobese diabetic (NOD) mouse, IL-10 has exhibited paradoxical effects. Systemic IL-10 expression prevented or delayed diabetes onset in NOD mice while local expression of IL-10 did not. As antigen-presenting cells (APCs) play a central role in the generation of primary T cell responses, the direct role of this gene in pancreatic beta (β) cell is not clear. The effects of IL-10 on the protection of β cells in vitro were examined. In the present study, we examined the effects of adenovirus vector-mediated murine IL-10 (mIL-10) gene transfer to islet cell line RINm5F cells in vitro and to explore if IL-10 overexpression may prevent cytokine-mediated cytotoxicity. We had established the recombinant adenovirus vector containing mIL-10 genes (Ad-mIL-10) successfully. After infection of Ad-mIL-10, both mRNA and protein were expressed in RINm5F cells. Moreover, RINm5F cells secreted IL-10 protein into culture medium. Ad-mIL-10 prevented IL-1β-mediated nitric oxide production from β cells in vitro as well as the suppression of β cells function as determined by glucose-stimulated insulin production. Furthermore, Ad-mIL-10 gene transfer led to a profound reduction of Fas-expressing β cells and caspase-3 activity which were induced by IL-1β and the apoptotic rates of Ad-mIL-10 group were decreased. These findings show that IL-10 gene transfer to β cells may be beneficial in maintaining cells function, protecting islet cells from apoptosis-mediated by factors, which showed the potential therapy for type 1 diabetes mellitus.

IL-10 delivery by AAV5 vector attenuates inflammation in mice with Pseudomonas pneumonia

Lung infections with Pseudomonas aeruginosa and other pathogens in cystic fibrosis (CF) cause progressive airway obstruction and tissue damage, the predominant cause of morbidity and mortality in CF. We investigated whether a recombinant adeno-associated virus type 5 (AAV5) vector expressing murine interleukin (IL)-10 (AAV5.Cbeta-mIL-10), a regulatory/anti-inflammatory cytokine, could decrease airway inflammation in IL-10 knockout mice chronically infected with mucoid P. aeruginosa. Mice that received AAV5.Cbeta-mIL10 through intratracheal inoculation produced IL-10 at an average of 25 000 pg/ml in the epithelial lining fluid (ELF) and 12 000 pg/g-lung tissue 6 weeks post-vector delivery, significantly higher levels than in placebo-treated mice. At 3 days post-infection, proinflammatory cytokines (IL-1beta, tumor necrosis factor (TNF)-alpha, macrophage inhibitory protein (MIP)-1alpha and (KC) in the ELF and lung homogenate were decreased (1-9 folds) in the AAV5.Cbeta-mIL10-treated mice accompanied by less pronounced and more localized neutrophil infiltration in lung sections, when compared with placebo-treated mice. These results suggest that AAV5.Cbeta-mIL10 induces IL-10 levels in the lungs mediating a significant anti-inflammatory response and making AAV-IL-10 gene transfer a potentially useful therapy in the treatment of CF lung disease.

Regulation of type 1 diabetes, tuberculosis, and asthma by parasites

Helminth infection is a worldwide health problem. In addition to directly causing disease, helminthic infection also affects the incidence and progression of other diseases by exerting immune modulatory effects. In animal models, infection with helminthic parasites can prevent autoimmune diseases and allergic inflammatory diseases, but worsens protective immunity to certain infectious pathogens. In this review, we summarize current findings regarding the effects of helminth infection on type 1 diabetes, tuberculosis, and asthma and discuss possible mechanisms through which helminthic parasites modulate host immunity. Investigating these mechanisms could lead to treatment strategies that specifically modulate the immune response as well as address fundamental questions in immunobiology.

Helminth infection can reduce insulitis and type 1 diabetes through CD25- and IL-10-independent mechanisms

Parasitic helminth infection has been shown to modulate pathological inflammatory responses in allergy and autoimmune disease. The aim of this study was to examine the effects of infection with a helminth parasite, Heligmosomoides polygyrus, on type 1 diabetes (T1D) in nonobese diabetic (NOD) mice and to elucidate the mechanisms involved in this protection. H. polygyrus inoculation at 5 weeks of age protected NOD mice from T1D until 40 weeks of age and also inhibited the more aggressive cyclophosphamide-induced T1D. Moreover, H. polygyrus inoculation as late as 12 weeks of age reduced the onset of T1D in NOD mice. Following H. polygyrus inoculation of NOD mice, pancreatic insulitis was markedly inhibited. Interleukin-4 (IL-4), IL-10, and IL-13 expression and the frequency of CD4(+) CD25(+) FoxP3(+) regulatory T cells were elevated in mesenteric and pancreatic lymph nodes. Depletion of CD4(+) CD25(+) T cells in vivo did not abrogate H. polygyrus-induced T1D protection, nor did anti-IL-10 receptor blocking antibody. These findings suggest that infection with H. polygyrus significantly inhibits T1D in NOD mice through CD25- and IL-10-independent mechanisms and also reduces the severity of T1D when administered late after the onset of insulitis.

Innovative Immune-Based Therapeutic Approaches for the Treatment of Type 1 Diabetes Mellitus

Type 1 diabetes mellitus is an autoimmune disease caused by a culmination of noxious processes of autoimmunity composed of various components of the innate and adaptive immune systems. Current treatment of type 1 diabetes focuses on restraining the endocrine disease without affecting the autoimmune process that underlies it. Prevention of this disease requires immune modulation and early intervention. New therapeutic approaches can be classified on the basis of the immunological arm targeted, that is, T-cell immune modulation (using cytokines, anti-CD3 monoclonal antibodies, and peptide MHC class II dimers), innate immune system modulation (using alpha-galactosylceramide or peptide 277), or specific antigen vaccination (glutamic acid decarboxylase and insulin). Here we review the most promising therapies developed based on these targets and emphasize those that have reached human phase clinical investigation.

Immunotherapy for the Prevention and Treatment of Type 1 Diabetes

A major effort has been on-going to develop immunotherapies to prevent and/or treat type 1 diabetes (T1D). This autoimmune disease is characterized by the selective loss of the insulin-producing beta cells via the cumulative effects of autoantigen-specific CD4(+) and CD8(+) T cells, autoantibodies, and activated antigen-presenting cells. To be applicable in a clinical setting, immunotherapies must suppress established beta-cell autoimmunity. Preclinical studies and recent clinical findings suggest that antigen-specific and systemic-based strategies can be effective in this regard. However, either approach alone may not be sufficient to block the diabetogenic response and establish long-term protection in the clinic. In this review, we will discuss the importance of both strategies and how a combinatorial approach to treat T1D is appealing.

Splenic cytokines in mice immunized with testicular germ cells

We previously established that two subcutaneous injections of viable syngeneic testicular germ cells (TGC) alone can induce CD4+ T cell-dependent experimental autoimmune orchitis (EAO) in mice. This model is histologically characterized by lymphocytic infiltration into the testes and the following aspermatogenesis. In the present study, we investigated the dynamics of splenic cytokines in EAO, using specific enzyme-linked immunosorbent assay. We found that splenic production of both type 1 helper T cell (Th1) and type 2 helper T cell (Th2)-related cytokines increased after the second but not the first immunization with TGC, indicating that secondary immune responses are critical to the EAO induction. However, the production of Th1-related cytokines became predominant at the clinical stage of EAO. Additionally, serum FSH and inhibin-B increased and decreased, respectively, during EAO. On the other hand, LH did not significantly change and testosterone temporally increased during the same period. These results indicate that both Th1- and Th2-related cytokines are involved at the pre-clinical phase of EAO, but that Th1- rather than Th2-related cytokines are responsible for the clinical phase when spermatogenesis is disrupted but the Leydig cell function is well preserved.

The pros and cons of immunomodulatory IL-10 gene therapy with recombinant AAV in a Cftr-/- -dependent allergy mouse model

Cystic fibrosis (CF) patients have decreased levels of lung epithelial interleukin (IL)-10 and increased levels of proinflammatory cytokines (tumor necrosis factor-alpha, IL-4, IL-8 and IL-6). This has also been documented in Cftr (cystic fibrosis transmembrane conductance regulator)-deficient mice (Cftr 489X(-/-), FABP-hCFTR(+/+)). Our laboratory has recently characterized a peculiar hyper-IgE phenotype in these mice, in response to Aspergillus fumigatus crude protein extract (Af-cpe). Thus, we hypothesized that sustained systemic circulating IL-10 levels achieved through skeletal muscle transduction with recombinant adeno-associated vectors expressing IL-10 (rAAV1-IL-10) would serve to downregulate Th1 and Th2 cytokine production. This in turn would dampen the allergic response in the Cftr(-/-)-dependent mouse model of allergic bronchopulmonary aspergillosis. After Af-cpe sensitization and airway challenge, mice treated with rAAV1-IL-10 had markedly lower IgE levels when compared to the control-treated rAAV1-GFP group. This was accompanied by a significant reduction in the levels of IL-5, IL-4 and IL-13 in the lung compartment. The lower lung cytokine profiles resulted in a near absence of eosinophil recruitment in the lung and a lower inflammatory response in the lung tissue of mice receiving rAAV1-IL-10. Unfortunately, sustained secretion of IL-10 from transduced muscle did lead to thrombocytopenia and splenomegaly in mice injected with rAAV1-IL-10. These results highlight that while IL-10 gene therapy is very effective for treating allergic responses caution must be taken with the prolonged secretion of IL-10.

AAV8-mediated gene transfer of interleukin-4 to endogenous beta-cells prevents the onset of diabetes in NOD mice

We have demonstrated the ability to deliver and express genes specifically in beta-cells for at least 6 months, using a murine insulin promoter (mIP) in a double-stranded, self-complementary AAV vector (dsAAV8-mIP). In this study, we evaluated the effects of dsAAV8-mIP-mediated delivery of interleukin 4 (mIL-4) to endogenous beta-cells in nonobese diabetic (NOD) mice. In 4-week-old NOD mice, the extent of gene transfer and expression in endogenous beta-cells after ip delivery of dsAAV8-mIP-enhanced green fluorescent protein (eGFP) was comparable to normal BALB/C mice. Further, after IP delivery of dsAAV8-mIP-IL4, expression of mIL-4 was detected in islets isolated from the treated mice and cultured. AAV8-mIP-mediated gene expression of mIL-4 in endogenous beta- cells of 4- and 8-week-old NOD mice prevented the onset of hyperglycemia in NOD mice and reduced the severity of insulitis. Moreover, expression of mIL-4 also maintained the level of CD4(+)CD25(+)FoxP3(+) cells, and adoptive transfer of splenocytes from nondiabetic dsAAV8-mIP-IL-4 mice to NODscid mice was able to block the diabetes induced by splenocytes co-adoptively transferred from nondiabetic dsAAV-mIP-eGFP mice. Taken together, these results demonstrate that local expression of mIL-4 in islets prevents islet destruction and blocks autoimmunity, partly through regulation of T-cell function.

Murine antithymocyte globulin therapy alters disease progression in NOD mice by a time-dependent induction of immunoregulation

OBJECTIVE

Antilymphocyte serum can reverse overt type 1 diabetes in NOD mice; yet, the therapeutic parameters and immunological mechanisms underlying the ability for this agent to modulate autoimmune responses against beta-cells are unclear, forming the rationale for this investigation.

RESEARCH DESIGN AND METHODS

A form of antilymphocyte serum, rabbit anti-mouse thymocyte globulin (mATG), was utilized in a variety of in vivo and in vitro settings, each for the purpose of defining the physiological, immunological, and metabolic activities of this agent, with particular focus on actions influencing development of type 1 diabetes.

RESULTS

We observed that mATG attenuates type 1 diabetes development in an age-dependent fashion, only proving efficacious at disease onset or in the late pre-diabetic phase (12 weeks of age). When provided at 12 weeks of age, mATG reversed pancreatic insulitis, improved metabolic responses to glucose challenge, and rapidly increased frequency of antigen-presenting cells in spleen and pancreatic lymph nodes. Surprisingly, mATG therapy dramatically increased, in an age-dependent fashion, the frequency and the functional activity of CD4(+)CD25(+) regulatory T-cells. Adoptive transfer/cotransfer studies of type 1 diabetes also support the concept that mATG treatment induces a stable and transferable immunomodulatory repertoire in vivo.

CONCLUSIONS

These findings indicate that an induction of immunoregulation, rather than simple lymphocyte depletion, contributes to the therapeutic efficacy of antithymocyte globulin and suggest that time-dependent windows for the ability to delay or reverse type 1 diabetes exist based on the capacity to enhance the functional activity of regulatory T-cells.

Beta-cell replacement for insulin-dependent diabetes mellitus

Beta-cell replacement is considered the optimal treatment for type 1 diabetes, however, it is hindered by a shortage of human organ donors. Given the difficulty of expanding adult beta cells in vitro, stem/progenitor cells, which can be expanded in tissue culture and induced to differentiate into multiple cell types, represent an attractive source for generation of cells with beta-cell properties. In the absence of well-characterized human pancreas progenitor cells, investigators are exploring the use of embryonic stem cells and stem/progenitor cells from other tissues. Once abundant surrogate beta cells are available, the challenge will be to protect them from recurring autoimmunity.

Genetic modification of cells for transplantation

Progress in gene therapy has produced promising results that translate experimental research into clinical treatment. Gene modification has been extensively employed in cell transplantation. The main barrier is an effective gene delivery system. Several viral vectors were utilized in end-stage differentiated cells. Recently, successful applications were described with adenovirus-associated vectors. As an alternative, embryonic stem cell- and stem cell-like systems were established for generation of tissue-specified gene-modified cells. Owing to the feasibility for genetic manipulations and the self-renewing potency of these cells they can be used in a way enabling large-scale in vitro production. This approach offers the establishment of in vitro cell culture systems that will deliver sufficient amounts of highly purified, immunoautologous cells suitable for application in regenerative medicine. In this review, the current technology of gene delivery systems to cells is recapitulated and the latest developments for cell transplantation are discussed.

Innocuous IFNgamma induced by adjuvant-free antigen restores normoglycemia in NOD mice through inhibition of IL-17 production

The role of Th17 cells in type I diabetes (TID) remains largely unknown. Glutamic acid decarboxylase (GAD) sequence 206–220 (designated GAD2) represents a late-stage epitope, but GAD2-specific T cell receptor transgenic T cells producing interferon γ (IFNγ) protect against passive TID. Because IFNγ is known to inhibit Th17 cells, effective presentation of GAD2 peptide under noninflammatory conditions may protect against TID at advanced disease stages. To test this premise, GAD2 was genetically incorporated into an immunoglobulin (Ig) molecule to magnify tolerance, and the resulting Ig-GAD2 was tested against TID at different stages of the disease. The findings indicated that Ig-GAD2 could not prevent TID at the preinsulitis phase, but delayed TID at the insulitis stage. More importantly, Ig-GAD2 sustained both clearance of pancreatic cell infiltration and β-cell division and restored normoglycemia when given to hyperglycemic mice at the prediabetic stage. This was dependent on the induction of splenic IFNγ that inhibited interleukin (IL)-17 production. In fact, neutralization of IFNγ led to a significant increase in the frequency of Th17 cells, and the treatment became nonprotective. Thus, IFNγ induced by an adjuvant free antigen, contrary to its usual inflammatory function, restores normoglycemia, most likely by localized bystander suppression of pathogenic IL-17–producing cells.

Induction of robust diabetes resistance and prevention of recurrent type 1 diabetes following islet transplantation by gene therapy

We have previously shown that the development of type 1 diabetes (T1D) can be prevented in nonobese diabetic (NOD) mice by reconstitution with autologous hemopoietic stem cells retrovirally transduced with viruses encoding MHC class II I-A beta-chain molecules associated with protection from the disease. In this study we examined whether a blockade of the programmed death-1 (PD-1)-programmed death ligand-1 (PD-L1) pathway, a major pathway known to control diabetes occurrence, could precipitate T1D in young NOD mice following reconstitution with autologous bone marrow retrovirally transduced with viruses encoding protective MHC class II I-A beta-chain molecules. In addition, we examined whether the expression of protective MHC class II alleles in hemopoietic cells could be used to prevent the recurrence of diabetes in mice with pre-existing disease following islet transplantation. Protection from the occurrence of T1D diabetes in young NOD mice by the expression of protective MHC class II I-A beta-chain molecules in bone marrow-derived hemopoietic cells was resistant to induction by PD-1-PD-L1 blockade. Moreover, reconstitution of NOD mice with pre-existing T1D autologous hemopoietic stem cells transduced with viruses encoding protective MHC class II I-A beta-chains allowed for the successful transplantation of syngeneic islets, resulting in the long-term reversal of T1D. Reversal of diabetes was resistant to induction by PD-1-PDL-1 blockade and depletion of CD25(+) T cells. These data suggest that expression of protective MHC class II alleles in bone marrow-derived cells establishes robust self-tolerance to islet autoantigens and is sufficient to prevent the recurrence of autoimmune diabetes following islet transplantation.

Cloning and characterization of recombinant rhesus macaque IL-10/Fc(ala-ala) fusion protein: a potential adjunct for tolerance induction strategies

The powerful anti-inflammatory and immunosuppressive activities of IL-10 make it attractive for supplemental therapy in translational tolerance induction protocols. This is bolstered by reports of IL-10-mediated inhibition of innate immunity, association of human stem cell and nonhuman primate (NHP) islet allograft tolerance with elevated serum IL-10, and evidence that systemic IL-10 therapy enhanced pig islets survival in mice. IL-10 has not been examined as adjunctive immunosuppression in NHP. To enable such studies, we cloned and expressed rhesus macaque (RM) IL-10 fused to a mutated hinge region of human IgG1 Fc to generate IL-10/Fc(ala-ala). RM IL-10/Fc(ala-ala) was purified to approximately 98% homogeneity by affinity chromatography and shown to be endotoxin-free (<0.008 EU/microg protein). The biological activity of IL-10/Fc(ala-ala) was demonstrated by (1) costimulation of the mouse mast cell line, MC/9 proliferation in a dose-dependent fashion, (2) suppression of LPS-induced septic shock in mice and (3) abrogation of LPS-induced secretion of proinflammatory cytokines/chemokines in vitro and in vivo in NHP. Notably, RM IL-10/Fc(ala-ala) had significantly greater potency than human IL-10/Fc(ala-ala) and exhibited a circulating half-life of approximately 14 days. The availability of this reagent will facilitate definitive studies to determine whether supplemental therapy with RM IL-10/Fc(ala-ala) can influence tolerance outcomes in NHP.

Ex vivo gene transfer of viral interleukin-10 to BB rat islets: no protection after transplantation to diabetic BB rats

Allogeneic and autoimmune islet destruction limits the success of islet transplantation in autoimmune diabetic patients. This study was designed to investigate whether ex vivo gene transfer of viral interleukin-10 (vIL-10) protects BioBreeding (BB) rat islets from autoimmune destruction after transplantation into diabetic BB recipients. Islets were transduced with adenoviral constructs (Ad) expressing the enhanced green fluorescent protein (eGFP), α-1 antitrypsin (AAT) or vIL-10. Transduction efficiency was demonstrated by eGFP-positive cells and vIL-10 production. Islet function was determined in vitro by measuring insulin content and insulin secretion and in vivo by grafting AdvIL-10-transduced islets into syngeneic streptozotocin (SZ)-diabetic, congenic Lewis (LEW.1 W) rats. Finally, gene-modified BB rat islets were grafted into autoimmune diabetic BB rats. Ad-transduction efficiency of islets increased with virus titre and did not interfere with insulin content and insulin secretion. Ad-transduction did not induce Fas on islet cells. AdvIL-10-transduced LEW.1 W rat islets survived permanently in SZ-diabetic LEW.1 W rats. In diabetic BB rats AdvIL-10-transduced BB rat islets were rapidly destroyed. Prolongation of islet culture prior to transplantation improved the survival of gene-modified islets in BB rats. Several genes including those coding for chemokines and other peptides associated with inflammation were down-regulated in islets after prolonged culture, possibly contributing to improved islet graft function in vivo. Islets transduced ex vivo with vIL-10 are principally able to cure SZ-diabetic rats. Autoimmune islet destruction in diabetic BB rats is not prevented by ex vivo vIL-10 gene transfer to grafted islets. Graft survival in autoimmune diabetic rats may be enhanced by improvements in culture conditions prior to transplantation.

Construction of miniantibodies for the in vivo study of human autoimmune diseases in animal models

Background

Phage display antibody libraries have been made from the lymphocytes of patients suffering from autoimmune diseases in which the antibodies are known to play a role in the pathogenesis or are important for the diagnosis of the disease. In the case of Celiac Disease, the immune response is directed against the autoantigen tissue transglutaminase. However, despite numerous studies, the role of these antibodies in the pathogenesis of this disease has not been elucidated.

Results

We were able to engineer specific anti-transglutaminase antibody fragments in the form called "miniantibody". These are produced by genetic fusion of anti-tTG scFv to Human, Mouse or Rat Fc domains, making them suitable for in vivo expression. The results obtained here indicate that the miniantibody molecule is efficiently secreted, and that the reactivity to the antigen is retained even after fusion to heterologous Fc domains. Further analysis demonstrate that the molecule is secreted as homodimeric, mimicking original antibody structure. Finally, the in vivo expression in mice leads to detectable serum levels with no apparent gross immune response by the host.

Conclusion

In this work we demonstrated the usefulness of a method for the in vivo expression of miniantibodies specific to transglutaminase, corresponding to the autoimmune specificity of Celiac Disease. This can be proposed as a general method to study the pathogenic role of autoimmune antibodies in autoimmune diseases.

Suppression of hyperglycemia in NOD mice after inoculation with recombinant vaccinia viruses

In autoimmune (type 1) diabetes, autoreactive lymphocytes destroy pancreatic beta-cells responsible for insulin synthesis. To assess the feasibility of gene therapy for type 1 diabetes, recombinant vaccinia virus (rVV) vectors were constructed expressing pancreatic islet autoantigens proinsulin (INS) and a 55-kDa immunogenic peptide from glutamic acid decarboxylase (GAD), and the immunomodulatory cytokine interleukin (IL)-10. To augment the beneficial effects of recombinant virus therapy, the INS and GAD genes were fused to the C terminus of the cholera toxin B subunit (CTB). Five-week-old non-obese diabetic (NOD) mice were injected once with rVV. Humoral antibody immune responses and hyperglycemia in the infected mice were analyzed. Only 20% of the mice inoculated with rVV expressing the CTB::INS fusion protein developed hyperglycemia, in comparison to 70% of the mice in the uninoculated animal group. Islets from pancreatic tissues isolated from euglycemic mice from this animal group showed no sign of inflammatory lymphocyte invasion. Inoculation with rVV producing CTB::GAD or IL-10 was somewhat less effective in reducing diabetes. Humoral antibody isotypes of hyperglycemic and euglycemic mice from all treated groups possessed similar IgG1/IgG2c antibody titer ratios from 19 to 32 wk after virus inoculation. In comparison with uninoculated mice, 11-wk-old NOD mice injected with virus expressing CTB::INS were delayed in diabetes onset by more than 4 wk. The experimental results demonstrate the feasibility of using rVV expressing CTB::INS fusion protein to generate significant protection and therapy against type 1 diabetes onset and progression.