TRI microparticles prevent inflammatory arthritis in a collagen-induced arthritis model

Licorice-regulated gut-joint axis for alleviating collagen-induced rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is partially affected by the integrity of the intestinal barrier. Licorice (GC), a medicinal and food-related herb, exhibits potent anti-inflammatory activity; however, studies on its mechanisms of action in RA are limited.

METHOD

Using a bovine type-II collagen-induced arthritis rat model, this study examined how GC influences the gut-joint axis to decrease RA. The Th17/Treg cell ratios in the blood, colon, and joints were also measured. Metabolomics and 16S rRNA sequencing were applied to explore the effects of variations in gut flora and metabolites.

RESULTS

The arthropathological slices, inflammation markers, and joint inflammation index scores in the GC treatment group significantly differed from those in the CIA group. Studies on the effect of GC on the gut-joint axis showed changes in the levels of lipopolysaccharide and diamine oxidase, both directly associated with intestinal permeability. ZO-1, occludin, and claudin-1, three intestinal tight-junction proteins, may express themselves more when exposed to GC. By maintaining an appropriate Th17/Treg cell ratio in the blood, colon, and joints, GC may reduce impaired to the intestinal barrier. An imbalance in the intestinal microenvironment, caused by modifications in gut flora and endogenous substances, can damage the intestinal barrier. GC may modify the relative abundances of Papillibacter, Clostridium, Eubacterium, Helicobacter, Provotella, and Barnesiella during RA treatment by repairing the intestinal barrier. The metabolic differences were mainly related to primary bile acid biosynthesis, pyrimidine metabolism, steroid biosynthesis, biotin metabolism, and sphingolipid metabolism. A fecal microbiota transplantation experiment confirmed the involvement of the gut microbiota and its metabolites in GC-mediated RA therapy.

CONCLUSION

The results demonstrated that GC repairs the intestinal barrier and adjusts the gut-joint axis to manage immunological imbalance in RA.

Drug delivery strategies for local immunomodulation in transplantation: Bridging the translational gap

Drug delivery strategies for local immunomodulation hold tremendous promise compared to current clinical gold-standard systemic immunosuppression as they could improve the benefit to risk ratio of life-saving or life-enhancing transplants. Such strategies have facilitated prolonged graft survival in animal models at lower drug doses while minimizing off-target effects. Despite the promising outcomes in preclinical animal studies, progression of these strategies to clinical trials has faced challenges. A comprehensive understanding of the translational barriers is a critical first step towards clinical validation of effective immunomodulatory drug delivery protocols proven for safety and tolerability in pre-clinical animal models. This review overviews the current state-of-the-art in local immunomodulatory strategies for transplantation and outlines the key challenges hindering their clinical translation.

ABCD of IA: A multi-scale agent-based model of T cell activation in inflammatory arthritis

Biomaterial-based agents have been demonstrated to regulate the function of immune cells in models of autoimmunity. However, the complexity of the kinetics of immune cell activation can present a challenge in optimizing the dose and frequency of administration. Here, we report a model of autoreactive T cell activation, which are key drivers in autoimmune inflammatory joint disease. The model is termed a multi-scale Agent-Based, Cell-Driven model of Inflammatory Arthritis (ABCD of IA). Using kinetic rate equations and statistical theory, ABCD of IA simulated the activation and presentation of autoantigens by dendritic cells, interactions with cognate T cells and subsequent T cell proliferation in the lymph node and IA-affected joints. The results, validated with in vivo data from the T cell driven SKG mouse model, showed that T cell proliferation strongly correlated with the T cell receptor (TCR) affinity distribution (TCR-ad), with a clear transition state from homeostasis to an inflammatory state. T cell proliferation was strongly dependent on the amount of antigen in antigenic stimulus event (ASE) at low concentrations. On the other hand, inflammation driven by Th17-inducing cytokine mediated T cell phenotype commitment was influenced by the initial level of Th17-inducing cytokines independent of the amount of arthritogenic antigen. The introduction of inhibitory artificial antigen presenting cells (iaAPCs), which locally suppress T cell activation, reduced T cell proliferation in a dose-dependent manner. The findings in this work set up a framework based on theory and modeling to simulate personalized therapeutic strategies in IA.

The therapeutic potential of immunoengineering for systemic autoimmunity

Disease-modifying drugs have transformed the treatment options for many systemic autoimmune diseases. However, an evolving understanding of disease mechanisms, which might vary between individuals, is paving the way for the development of novel agents that operate in a patient-tailored manner through immunophenotypic regulation of disease-relevant cells and the microenvironment of affected tissue domains. Immunoengineering is a field that is focused on the application of engineering principles to the modulation of the immune system, and it could enable future personalized and immunoregulatory therapies for rheumatic diseases. An important aspect of immunoengineering is the harnessing of material chemistries to design technologies that span immunologically relevant length scales, to enhance or suppress immune responses by re-balancing effector and regulatory mechanisms in innate or adaptive immunity and rescue abnormalities underlying pathogenic inflammation. These materials are endowed with physicochemical properties that enable features such as localization in immune cells and organs, sustained delivery of immunoregulatory agents, and mimicry of key functions of lymphoid tissue. Immunoengineering applications already exist for disease management, and there is potential for this new discipline to improve disease modification in rheumatology.

Pathophysiology to advanced intra-articular drug delivery strategies: Unravelling rheumatoid arthritis

Rheumatoid arthritis (RA) is one of the most prevalent life-long autoimmune diseases with an unknown genesis. It primarily causes chronic inflammation, pain, and synovial joint-associated cartilage and bone degradation. Unfortunately, limited information is available regarding the etiology and pathogenesis of this chronic joint disorder. In the last few decades, an improved understanding of RA pathophysiology about key immune cells, antibodies, and cytokines has inspired the development of several anti-rheumatic drugs and biopharmaceuticals to act on RA-affected joints. However, life-long frequent systemic high doses of commercially available drugs are currently a limiting factor in the efficient management of RA. To address this issue, various single and double-barrier intra-articular drug delivery systems (IA-DDSs) such as nanocarriers, microparticles, hydrogels, and particles-hybrid hydrogel composite have been developed which can exclusively target the RA-affected joint cavity and release the precisely controlled therapeutic drug concentration for prolonged time whilst avoiding the systemic toxicity. This review provides a comprehensive overview of the pathogenesis of RA and discusses the rational design and development of biomaterials-based novel IA-DDs, ranging from conventional to advanced systems, for improved treatment of RA. Therefore, this review aims to unravel the pathophysiology of rheumatoid arthritis and explore cutting-edge IA-DD strategies exploiting biomaterials. It offers researchers a consolidated and up-to-date resource platform to analyze existing knowledge, identify research gaps, and contribute to the scientific literature.

Current Immunotherapy Strategies for Rheumatoid Arthritis: The Immunoengineering and Delivery Systems

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease accompanied by persistent multiarticular synovitis and cartilage degradation. The present clinical treatments are limited to disease-modifying anti-rheumatic drugs (DMARDs) and aims to relieve pain and control the inflammation of RA. Despite considerable advances in the research of RA, the employment of current clinical procedure is enormous, hindered by systemic side effect, frequent administration, tolerance from long-lasting administration, and high costs. Emerging immunoengineering-based strategies, such as multiple immune-active nanotechnologies via mechanism-based immunology approaches, have been developed to improve specific targeting and to reduce adverse reactions for RA treatments. Here, we review recent studies in immunoengineering for the treatment of RA. The prospect of future immunoengineering treatment for RA has also been discussed.

Immunomodulatory Microparticles Epigenetically Modulate T Cells and Systemically Ameliorate Autoimmune Arthritis

Disease modifying antirheumatic drugs (DMARDs) have improved the prognosis of autoimmune inflammatory arthritides but a large fraction of patients display partial or nonresponsiveness to front-line DMARDs. Here, an immunoregulatory approach based on sustained joint-localized release of all-trans retinoic acid (ATRA), which modulates local immune activation and enhances disease-protective T cells and leads to systemic disease control is reported. ATRA imprints a unique chromatin landscape in T cells, which is associated with an enhancement in the differentiation of naïve T cells into anti-inflammatory regulatory T cells (Treg ) and suppression of Treg destabilization. Sustained release poly-(lactic-co-glycolic) acid (PLGA)-based biodegradable microparticles encapsulating ATRA (PLGA-ATRA MP) are retained in arthritic mouse joints after intra-articular (IA) injection. IA PLGA-ATRA MP enhance migratory Treg which in turn reduce inflammation and modify disease in injected and uninjected joints, a phenotype that is also reproduced by IA injection of Treg . PLGA-ATRA MP reduce proteoglycan loss and bone erosions in the SKG and collagen-induced arthritis mouse models of autoimmune arthritis. Strikingly, systemic disease modulation by PLGA-ATRA MP is not associated with generalized immune suppression. PLGA-ATRA MP have the potential to be developed as a disease modifying agent for autoimmune arthritis.

Emerging local immunomodulatory strategies to circumvent systemic immunosuppression in cell transplantation

INTRODUCTION

Cell transplantation is a promising curative therapeutic strategy whereby impaired organ functions can be restored without the need for whole organ transplantation. A key challenge in allotransplantation is the requirement for life-long systemic immunosuppression to prevent rejection, which is associated with serious adverse effects such as increased risk of opportunistic infections and the development of neoplasms. This challenge underscores the urgent need for novel strategies to prevent graft rejection while abrogating toxicity-associated adverse events.

AREAS COVERED

We review recent advances in immunoengineering strategies for localized immunomodulation that aim to support allograft function and provide immune tolerance in a safe and effective manner.

EXPERT OPINION

Immunoengineering strategies are tailored approaches for achieving immunomodulation of the transplant microenvironment. Biomaterials can be adapted for localized and controlled release of immunomodulatory agents, decreasing the effective dose threshold and frequency of administration. The future of transplant rejection management lies in the shift from systemic to local immunomodulation with suppression of effector and activation of regulatory T cells, to promote immune tolerance.

Local induction of regulatory T cells prevents inflammatory bone loss in ligature-induced experimental periodontitis in mice

Periodontitis (periodontal disease) is a highly prevalent disease, affecting over 65 million adults in the United States alone. Characterized by an overburden of invasive bacteria, gum inflammation and plaque buildup, over time, these symptoms can result in severe loss of gingival tissue attachment, bone resorption and even tooth loss. Although current treatments (local antibiotics and scaling and root planing procedures) target the bacterial dysbiosis, they do not address the underlying inflammatory imbalance in the periodontium. In the healthy steady state, the body naturally combats destructive, imbalanced inflammatory responses through regulatory pathways mediated by cells such as regulatory T cells (Tregs). Consequently, we hypothesized that local enrichment of regulatory lymphocytes (Tregs) could restore local, immunological homeostasis and prevent the main outcome of bone loss. Accordingly, we locally delivered a combination of TGFβ, Rapamycin, and IL2 microspheres in a ligature-induced murine periodontitis model. Herein, we have demonstrated this preventative treatment decreases alveolar bone loss, increases the local ratio of Tregs to T effector cells and changes the local microenvironment’s expression of inflammatory and regenerative markers. Ultimately, these Treg-inducing microspheres appear promising as a method to improve periodontitis outcomes and may be able to serve as a platform delivery system to treat other inflammatory diseases.

Immunomodulatory and immunoregulatory nanomedicines for autoimmunity

Autoimmune diseases, caused by cellularly and molecularly complex immune responses against self-antigens, are largely treated with broad-acting, non-disease-specific anti-inflammatory drugs. These compounds can attenuate autoimmune inflammation, but tend to impair normal immunity against infection and cancer, cannot restore normal immune homeostasis and are not curative. Nanoparticle (NP)- and microparticle (MP)-based delivery of immunotherapeutic agents affords a unique opportunity to not only increase the specificity and potency of broad-acting immunomodulators, but also to elicit the formation of organ-specific immunoregulatory cell networks capable of inducing bystander immunoregulation. Here, we review the various NP/MP-based strategies that have so far been tested in models of experimental and/or spontaneous autoimmunity, with a focus on mechanisms of action.

Local delivery strategies to restore immune homeostasis in the context of inflammation

Immune homeostasis is maintained by a precise balance between effector immune cells and regulatory immune cells. Chronic deviations from immune homeostasis, driven by a greater ratio of effector to regulatory cues, can promote the development and propagation of inflammatory diseases/conditions (i.e., autoimmune diseases, transplant rejection, etc.). Current methods to treat chronic inflammation rely upon systemic administration of non-specific small molecules, resulting in broad immunosuppression with unwanted side effects. Consequently, recent studies have developed more localized and specific immunomodulatory approaches to treat inflammation through the use of local biomaterial-based delivery systems. In particular, this review focuses on (1) local biomaterial-based delivery systems, (2) common materials used for polymeric-delivery systems and (3) emerging immunomodulatory trends used to treat inflammation with increased specificity.

Evolution of nanomedicines for the treatment of autoimmune disease: From vehicles for drug delivery to inducers of bystander immunoregulation

Over the last two decades, the nanomedicine field has witnessed an explosive growth of research on the development of nanoparticle/microparticle (NP/MP)-based compounds for the treatment of autoimmune diseases. Studies have evaluated compounds generated with a broad range of materials with different shapes, sizes, surface chemistries and structures. A number of active pharmaceutical ingredients, including immunosuppressants, cytokines, nucleotides, peptides, proteins and immunomodulators of various types have been encapsulated into or incorporated onto the surface of these compounds, either individually or in combination, and delivered to animal models of autoimmune inflammation via different administration routes. These NP/MP-based compounds can be categorized into four different groups based on their intended mechanisms of action. Here, we review the engineering designs, the pharmacodynamic and therapeutic correlates and the disease specificity of nanomedicines belonging to each of these groups.