Tolerogenic IL-10-engineered dendritic cell-based therapy to restore antigen-specific tolerance in T cell mediated diseases

Artificial Tolerogenic Dendritic Cell-Derived Vesicles Prepared by High-Pressure Homogenization for Potent Immunotherapy of Type 1 Diabetes

Tolerogenic dendritic cells (tolDCs) have emerged as a promising immunotherapeutic approach for type 1 diabetes (T1D) by promoting immune tolerance and modulating autoimmune responses against pancreatic β cells. However, their clinical applications are challenged by various limitations including cell viability, scalability, and manufacturing complexities. As an alternative, tolDC-derived extracellular vesicles could address some limitations of cell-based therapies, though their application in T1D treatment remains unexplored. Here, we developed the artificial tolDC-derived vesicles (ACDVtolDC) by a high-pressure homogenization approach, which retained immunosuppressive properties with high yield production and stability that improved the scalability for potential clinical use. In both chemically induced (STZ) and spontaneous (NOD) T1D mouse models, ACDVtolDC exhibited abilities to reduce T cell infiltration by approximately 4-fold in the pancreas and re-establish the balance between regulatory and cytotoxic T cells to a healthy baseline, thereby preserving β cells and ameliorating T1D onset. Additionally, the therapeutic effect of ACDVtolDC was superior to that of the tolDC treatment. These findings highlighted ACDVtolDC as a potent vesicle-based immunotherapy for T1D, offering practical advantages over traditional tolDC therapies.

Extracellular vesicles from human semen induce unique tolerogenic phenotypes in vaginal dendritic cells and regulatory T lymphocytes

Introduction

The regulation of immune responses to promote tolerance to the fetus is critical for successful pregnancy. An understudied aspect of this process is the initiation of regulation pre-conception via exposure to semen. Our study aimed to understand how semen impacts recipient dendritic cells (DCs) and their subsequent role in shaping CD4 T cell differentiation.

Methods

Monocyte-derived DCs (MoDCs) were exposed to semen extracellular vesicles (SEV) or vesicle-depleted semen plasma (VDSP). Phenotypic and functional markers were analyzed using flow cytometry. We also exposed epithelial sheets from vaginal tissue to SEV and VDSP, and measured the number and marker expression of emigrating cells. Finally, we tested how SEV- or VDSP-exposed DCs altered CD4 T cell differentiation by co-culturing exposed MoDCs or tissue emigrated cells with autologous naïve CD4 T cells.

Results

MoDCs exhibited a significant increase of CD141, CD1a, CD38, and ILT4 expression when exposed to SEV or VDSP. A unique feature of semen-treated MoDCs was expression of indoleamine 2,3-dioxygenase (IDO), a potent contributor to the induction of regulatory T cells (Tregs). SEV but not VDSP significantly increased the emigration of intraepithelial DCs. Additionally, SEV significantly enhanced the expression of multiple immunoregulatory markers in the emigrated DCs. After co-culture, we observed significantly more FOXP3+ Tregs expressing high levels of TIGIT in the groups that were initially exposed to SEV.

Discussion

These findings indicate that exposure to SEV induces a tolerogenic program in DCs that can direct differentiation of a unique memory Treg subset, primed for expansion and presumably destined to support a successful pregnancy.

Advances in Regulatory Cell Therapy for Type 1 Diabetes: Emerging Strategies and Future Directions

Type 1 diabetes (T1D) is an autoimmune disorder characterized by the destruction of insulin-producing β-cells in the pancreas. Despite advances in insulin therapy and β-cell replacement, a definitive cure addressing the underlying cause of the disease, that is the loss of immune tolerance to β-cells remains elusive. Emerging strategies to reshape the immune response to pancreatic autoantigens include the adoptive transfer of ex vivo cultured regulatory cells, either mesenchymal stem cells (MSCs), regulatory T cells (Tregs), or dendritic cells (DCs), collectively known as regulatory cell therapy. This review aims to provide an overview of the regulatory cell-based approaches for T1D currently under development. Although several clinical trials have demonstrated the safety of in vivo administration of regulatory cells to T1D patients, only mild signs of efficacy have been reported. The most promising results were observed in patients with shorter disease duration and higher residual β-cell mass, suggesting that early interventions may result in clinical benefit. Significant challenges remain, including the long-term efficacy and stability of the infused products. In the future, approaches combining regulatory cell-based therapies with immunomodulatory agents or strategies to restore the damaged insulin-producing cells may hold the key to achieving a functional cure for T1D.

In vivo armed macrophages curb liver metastasis through tumor-reactive T-cell rejuvenation

Despite recent progress in cancer treatment, liver metastases persist as an unmet clinical need. Here, we show that arming liver and tumor-associated macrophages in vivo to co-express tumor antigens (TAs), IFNα, and IL-12 unleashes robust anti-tumor immune responses, leading to the regression of liver metastases. Mechanistically, in vivo armed macrophages expand tumor reactive CD8+ T cells, which acquire features of progenitor exhausted T cells and kill cancer cells independently of CD4+ T cell help. IFNα and IL-12 produced by armed macrophages reprogram antigen presenting cells and rewire cellular interactions, rescuing tumor reactive T cell functions. In vivo armed macrophages trigger anti-tumor immunity in distinct liver metastasis mouse models of colorectal cancer and melanoma, expressing either surrogate tumor antigens, naturally occurring neoantigens or tumor-associated antigens. Altogether, our findings support the translational potential of in vivo armed liver macrophages to expand and rejuvenate tumor reactive T cells for the treatment of liver metastases.

IL-10 signaling modulates PRKN methylation and influences STAT3 activity to drive regulatory macrophage differentiation

The pathogenesis of many immune disorders is linked to regulatory macrophage dysfunction. The mechanism underlying it is unclear. The objective of this study is to examine the mechanism by which the PRKN ubiquitin protein ligase (PRKN) inhibits the development of regulatory macrophages (Mreg). In this study, dust mite antigens were used as the specific allergens to establish an airway allergy (AA) mouse model. Flow cytometry cell sorting was used to isolate macrophages from the airway tissues. According to the results, the Prkn gene inhibition led to an increase in the number of Mregs in macrophages. Mregs demonstrated the capacity to suppress Th2 polarization, in which IL-10 played a critical role. Pan macrophages isolated from Prkn-deficient mice were more capable of suppressing the activities of other immune cells. PRKN was required for maintaining the hyperubiquitous status of signal transducer and transcriptional activator-3 (STAT3) in macrophages. Exposure to dust mite antigen increased the expression of PRKN in macrophages. IL-10 suppressed PRKN in macrophages by inducing its promoter hypermethylation. PRKN inhibition mitigated the experimental AA. To sum up, PRKN maintains the hyper ubiquitous status of STAT3 and restricts the expression of IL-10 in macrophages, which compromises their immune suppressive functions. Inhibition of PRKN increases Mreg development and mitigates AA. The data suggest that the regulation of Mreg has translation potential to be used in the treatment of immune disorders such as AA.

Regulation of antigen presentation and interleukin 10 production in murine dendritic cells via the oxidative stimulation of cell membrane using a polycation-porphyrin-conjugate-immobilized cell culture dish

Tolerogenic dendritic cells with professional antigen presentation via major histocompatibility complex molecules, co-stimulatory molecules (CD80/86), and interleukin 10 production have attracted significant attention as cellular therapies for autoimmune, allergic, and graft-versus-host diseases. In this study, we developed a cell culture dish equipped with polycation-porphyrin-conjugate-immobilized glass (PA-HP-G) to stimulate immature murine dendritic cell (iDCs). Upon irradiation with a red light at 635 nm toward the PA-HP-G surface, singlet oxygen was generated by the immobilized porphyrins on the PA-HP-G surface. When iDCs were cultured on the PA-HP-G surface, moderate light irradiation generated lipid radicals without excessive generation of reactive oxygen species in the cytoplasm and nucleus, which led to the oxidative stimulation of the iDC cell membrane without cell death. Light irradiation changed the morphology of dendritic cells on the PA-HP-G surface to a tree-like structure with dendrites, accelerated their maturation, and enhanced the antigen-presenting ability for the ovalbumin peptide via major histocompatibility complex class I molecules. Additionally, the antigen-presenting dendritic cells on the PA-HP-G surface produced the anti-inflammatory cytokine interleukin 10 upon light irradiation. These results indicated that upon moderate light irradiation, the PA-HP-G surface regulated the maturation of iDCs into tolerogenic dendritic cells. STATEMENT OF SIGNIFICANCE: • Cell culture dish is developed for selective oxidative stimulus of cell membrane. • 1O2 is generated from polycation/porphyrin-immobilized glass by light irradiation. • Lipid radicals are generated without generation of ROS in cytoplasm and nuclei. • Immature dendritic cells are maturated by oxidative stimulation of cell membrane. • Oxidative membrane stimulus enhances antigen-presentation and IL-10 secretion.

A comprehensive overview of tolerogenic vaccine adjuvants and their modes of action

Tolerogenic vaccines represent a therapeutic approach to induce antigen-specific immune tolerance to disease-relevant antigens. As general immunosuppression comes with significant side effects, including heightened risk of infections and reduced anti-tumor immunity, antigen-specific tolerance by vaccination would be game changing in the treatment of immunological conditions such as autoimmunity, anti-drug antibody responses, transplantation rejection, and hypersensitivity. Tolerogenic vaccines induce antigen-specific tolerance by promoting tolerogenic antigen presenting cells, regulatory T cells, and regulatory B cells, or by suppressing or depleting antigen-specific pathogenic T and B cells. The design of tolerogenic vaccines vary greatly, but they all deliver a disease-relevant antigen with or without a tolerogenic adjuvant. Tolerogenic adjuvants are molecules which mediate anti-inflammatory or immunoregulatory effects and enhance vaccine efficacy by modulating the immune environment to favor a tolerogenic immune response to the vaccine antigen. Tolerogenic adjuvants act through several mechanisms, including immunosuppression, modulation of cytokine signaling, vitamin signaling, and modulation of immunological synapse signaling. This review seeks to provide a comprehensive examination of tolerogenic adjuvants currently utilized in tolerogenic vaccines, describing their mechanism of action and examples of their use in human clinical trials and animal models of disease.

Evolving understanding of autoimmune mechanisms and new therapeutic strategies of autoimmune disorders

Autoimmune disorders are characterized by aberrant T cell and B cell reactivity to the body's own components, resulting in tissue destruction and organ dysfunction. Autoimmune diseases affect a wide range of people in many parts of the world and have become one of the major concerns in public health. In recent years, there have been substantial progress in our understanding of the epidemiology, risk factors, pathogenesis and mechanisms of autoimmune diseases. Current approved therapeutic interventions for autoimmune diseases are mainly non-specific immunomodulators and may cause broad immunosuppression that leads to serious adverse effects. To overcome the limitations of immunosuppressive drugs in treating autoimmune diseases, precise and target-specific strategies are urgently needed. To date, significant advances have been made in our understanding of the mechanisms of immune tolerance, offering a new avenue for developing antigen-specific immunotherapies for autoimmune diseases. These antigen-specific approaches have shown great potential in various preclinical animal models and recently been evaluated in clinical trials. This review describes the common epidemiology, clinical manifestation and mechanisms of autoimmune diseases, with a focus on typical autoimmune diseases including multiple sclerosis, type 1 diabetes, rheumatoid arthritis, systemic lupus erythematosus, and sjögren's syndrome. We discuss the current therapeutics developed in this field, highlight the recent advances in the use of nanomaterials and mRNA vaccine techniques to induce antigen-specific immune tolerance.

Leveraging current insights on IL-10-producing dendritic cells for developing effective immunotherapeutic approaches

Dendritic cells (DC) are professional antigen-presenting cells involved in promoting and controlling immune responses. Different subsets of DC, named tolerogenic (tol)DC, play a critical role in the maintenance of tissue homeostasis and in fostering tolerance. These unique skills make tolDC especially attractive for strategies aimed at re-establishing/inducing tolerance in immune-mediated conditions. The generation of potent tolDC in vitro from peripheral blood monocytes has seen remarkable advancements. TolDC modulate T cell dynamics by favoring regulatory T cells (Tregs) and curbing effector/pathogenic T cells. Among the several methods developed for in vitro tolDC generation, IL-10 conditioning has been proven to be the most efficient, as IL-10-modulated tolDC were demonstrated to promote Tregs with the strongest suppressive activities. Investigating the molecular, metabolic, and functional profiles of tolDC uncovers essential pathways that facilitate their immunoregulatory functions. This Review provides an overview of current knowledge on the role of tolDC in health and disease, focusing on IL-10 production, functional characterization of in vitro generated tolDC, molecular and metabolic changes occurring in tolDC induced by tolerogenic agents, clinical applications of tolDC-based therapy, and finally new perspectives in the generation of effective tolDC.

MerTK Induces Dysfunctional Dendritic Cells by Metabolic Reprogramming

Checkpoint inhibitors, specifically anti-programmed cell death protein 1 (PD1), have shown success in treating metastatic melanoma; however, some patients develop resistance. Dendritic cells (DC) play a key role in initiating an immune response, but in certain circumstances they become ineffective. We investigated the role of MerTK, a receptor tyrosine kinase responsible for myeloid cell clearance of dead cells, in the regulation of DC function and metabolism in the tumor microenvironment. Tumors resistant to anti-PD1 exhibited increased levels of MerTK+ DCs. Treating wild-type DCs with apoptotic melanoma cells in vitro resulted in increased MerTK expression, elevated mitochondrial respiration and fatty acid oxidation, and reduced T-cell stimulatory capacity, all characteristics of dysfunctional DCs. In contrast, dead cells had only limited effect on the metabolism of MerTK-deficient DCs, which instead maintained an antigen-presenting, stimulatory phenotype. The efficacy of anti-PD1 to slow tumor progression and induce antigen specific T-cell infiltration was markedly increased in mice with selective ablation of MerTK in the DC compartment, suggesting the possibility of therapeutically targeting MerTK to modulate DC metabolism and function and enhance anti-PD1 therapy.

TRIM41 contributes to the pathogenesis of airway allergy by compromising dendritic cells' tolerogenic properties

Dendritic cells (DC) play a crucial role in the initiation of immune responses. TRIM41, an E3 ubiquitin ligase, can facilitate targeting protein degradation. The purpose of this study is to analyze the role of TRIM41 in the pathogenesis of airway allergy (AA) and the impact of regulating TRIM41 on suppressing AA. We observed that the airway DCs of AA mice had a higher expression of Trim41. The expression of Trim41 in airway DCs was associated with the DCs' tolerogenic functions of AA mice. The AA responses, including increased amounts of eosinophil peroxidase, mast cell protease-1, Th2 cytokines, and specific IgE in bronchoalveolar lavage fluids, were positively correlated with the Trim41 expression in mouse airway DCs. TRIM41 induced c-Maf degradation and interfered with the Il10 expression in airway DCs, which could be counteracted by inhibiting TRIM41. Regulation of TRIM41 mitigated experimental AA responses.

Development Perspectives for Curative Technologies in Primary Demyelinating Disorders of the Central Nervous System with Neuromyelitis Optica Spectrum Disorder (NMOSD) and Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease (MOGAD) at the Forefront

Primary demyelinating disorders of the central nervous system (CNS) include multiple sclerosis and the orphan conditions neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein IgG-associated disease (MOGAD). Curative technologies under development aim to selectively block autoimmune reactions against specific autoantigens while preserving the responsiveness of the immune system to other antigens. Our analysis focused on target patient selection for such developments, carefully considering the relevant clinical, regulatory, and market-related aspects. We found that the selection of patients with orphan conditions as target populations offers several advantages. Treatments for orphan conditions are associated with limited production capacity, qualify for regulatory incentives, and may require significantly shorter and lower-scale clinical programs. Furthermore, they may meet a higher acceptable cost-effectiveness threshold in order to compensate for the low numbers of patients to be treated. Finally, curative technologies targeting orphan indications could enter less competitive markets with lower risk of generic price erosion and would benefit from additional market protection measures available only for orphan products. These advantages position orphan conditions and subgroups as the most attractive target indications among primary demyelinating disorders of the CNS. The authors believe that after successful proof-of-principle demonstrations in orphan conditions, broader autoimmune patient populations may also benefit from the success of these pioneering developments.

Antigen-specific immunotherapy via delivery of tolerogenic dendritic cells for multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system resulting from loss of immune tolerance. Many disease-modifying therapies for MS have broad immunosuppressive effects on peripheral immune cells, but this can increase risks of infection and attenuate vaccine-elicited immunity. A more targeted approach is to re-establish immune tolerance in an autoantigen-specific manner. This review discusses methods to achieve this, focusing on tolerogenic dendritic cells. Clinical trials in other autoimmune diseases also provide learnings with regards to clinical translation of this approach, including identification of autoantigen(s), selection of appropriate patients and administration route and frequency.

Therapeutic induction of antigen-specific immune tolerance

The development of therapeutic approaches for the induction of robust, long-lasting and antigen-specific immune tolerance remains an important unmet clinical need for the management of autoimmunity, allergy, organ transplantation and gene therapy. Recent breakthroughs in our understanding of immune tolerance mechanisms have opened new research avenues and therapeutic opportunities in this area. Here, we review mechanisms of immune tolerance and novel methods for its therapeutic induction.

Immunosuppressive microvesicles-mimetic derived from tolerant dendritic cells to target T-lymphocytes for inflammation diseases therapy

The utilization of extracellular vesicles (EV) in immunotherapy, aiming at suppressing peripheral immune cells responsible for inflammation, has demonstrated significant efficacy in treating various inflammatory diseases. However, the clinical application of EV has faced challenges due to their inadequate targeting ability. In addition, most of the circulating EV would be cleared by the liver, resulting in a short biological half-life after systemic administration. Inspired by the natural microvesicles (MV, as a subset of large size EV) are originated and shed from the plasma membrane, we developed the immunosuppressive MV-mimetic (MVM) from endotoxin tolerant dendritic cells (DC) by a straightforward and effective extrusion approach, in which DC surface proteins were inherited for providing the homing ability to the spleen, while αCD3 antibodies were conjugated to the MVM membranes for specific targeting of T cells. The engineered MVM carried a large number of bioactive cargos from the parental cells, which exhibited a remarkable ability to promote the induction of regulatory T cells (Treg) and polarization of anti-inflammatory M2 macrophages. Mechanistically, the elevated Treg level by MVM was mediated due to the upregulation of miR-155-3p. Furthermore, it was observed that systemic and local immunosuppression was induced by MVM in models of sepsis and rheumatoid arthritis through the improvement of Treg and M2 macrophages. These findings reveal a promising cell-free strategy for managing inflammatory responses to infections or tissue injury, thereby maintaining immune homeostasis.

Regulatory dendritic cell therapy in organ transplantation

PURPOSE OF REVIEW

Regulatory dendritic cells (DCregs; also 'tolerogenic DCs'), innate immune cells that regulate the alloimmune response, are a novel cellular therapy for organ transplantation. Preliminary results from early-phase clinical trials in live donor kidney and liver transplantation are promising. This follows many years of research elucidating mechanisms of action and utility of DCregs. Herein, we review early-phase clinical trial observations and recent advances in the production, modification, and future-trajectory of DCreg in organ transplantation.

RECENT FINDINGS

Preclinical work has demonstrated the ability of adoptively transferred DCreg to abrogate ischemia-reperfusion injury and promote long-term allograft survival. Good Manufacturing Practice-grade DCregs have been generated in adequate numbers for early-phase trials of autologous DCregs in kidney transplantation and donor-derived DCreg in liver transplantation. These trials have demonstrated feasibility and safety, with preliminary evidence of an influence on host immune reactivity. In both kidney and liver transplantation, reduced effector CD8 + T-cells have been noted, together with other changes that may be conducive to reduced dependence on immunosuppressive therapy.

SUMMARY

Substantial progress has been made in bringing DCreg to clinical testing in organ transplantation. Additional clinical and mechanistic studies are now needed to further explore and garner the full potential of DCreg in organ transplantation.

Role of Regulatory T Cells and Their Potential Therapeutic Applications in Celiac Disease

Celiac disease (CeD) is a T-cell-mediated immune disease, in which gluten-derived peptides activate lamina propria effector CD4+ T cells. While this effector T cell subset produces proinflammatory cytokines, which cause substantial tissue injury in vivo, additional subsets of T cells exist with regulatory functions (Treg). These subsets include CD4+ type 1 regulatory T cells (Tr1) and CD4+ CD25+ T cells expressing the master transcription factor forkhead box P3 (Foxp3) that may have important implications in disease pathogenesis. In this review, we provide an overview of the current knowledge about the effects of immunomodulating cytokines on CeD inflammatory status. Moreover, we outline the main Treg cell populations found in CeD and how their regulatory activity could be influenced by the intestinal microenvironment. Finally, we discuss the Treg therapeutic potential for the development of alternative strategies to the gluten-free diet (GFD).

IL-10-Engineered Dendritic Cells Modulate Allogeneic CD8+ T Cell Responses

Tolerogenic dendritic cells (tolDC) play a central role in regulating immune homeostasis and in promoting peripheral tolerance. These features render tolDC a promising tool for cell-based approaches aimed at inducing tolerance in T-cell mediated diseases and in allogeneic transplantation. We developed a protocol to generate genetically engineered human tolDC overexpressing IL-10 (DCIL-10) by means of a bidirectional lentiviral vector (LV) encoding for IL-10. DCIL-10 promote allo-specific T regulatory type 1 (Tr1) cells, modulate allogeneic CD4+ T cell responses in vitro and in vivo, and are stable in a pro-inflammatory milieu. In the present study, we investigated the ability of DCIL-10 to modulate cytotoxic CD8+ T cell responses. We demonstrate that DCIL-10 reduces allogeneic CD8+ T cell proliferation and activation in primary mixed lymphocyte reactions (MLR). Moreover, long-term stimulation with DCIL-10 induces allo-specific anergic CD8+ T cells without signs of exhaustion. DCIL-10-primed CD8+ T cells display limited cytotoxic activity. These findings indicate that stable over-expression of IL-10 in human DC leads to a population of cells able to modulate cytotoxic allogeneic CD8+ T cell responses, overall indicating that DCIL-10 represent a promising cellular product for clinical applications aimed at inducing tolerance after transplantation.