Nanoemulsions Target to Ectopic Lymphoids in Inflamed Joints to Restore Immune Tolerance in Rheumatoid Arthritis

Engineering M2 macrophage-derived exosomes modulate activated T cell cuproptosis to promote immune tolerance in rheumatoid arthritis

Nanomedicines for immune modulation have made advancements in the treatment of rheumatoid arthritis (RA). However, due to aberrations in patients' immune systems, inducing antigen-specific immune tolerance while halting disease progression remains a significant challenge. Here, we develop a highly targeted multifunctional nanocomplex, termed M2Exo@CuS-CitP-Rapa (M2CPR), with the aim of selectively inhibiting inflammatory immune reactions while promoting immune tolerance towards specific antigens. M2CPR specifically targets inflammatory tissues in RA, delivering CuS NPs, CitP, Rapa, and endogenous anti-inflammatory factors, thereby ameliorating the inflammatory joint microenvironment. CuS NPs induce Cuproptosis of activated T cells, whose fragments are engulfed by resident or recruited macrophages, resulting in abundant production of TGF-β. TGF-β acts synergistically with Rapa to induce the iDCs into tDCs. tDCs present CitP to Naive T cells, promoting Tregs differentiation. Tregs, in turn, produce more TGF-β, inducing tDCs differentiation, thereby establishing a cycle of immune tolerance. Through in vitro and in vivo experiments, we validate that M2CPR can induce robust and durable antigen-specific immune tolerance, offering a new paradigm for RA therapy.

Revolutionizing rheumatoid arthritis treatment with emerging cutaneous drug delivery systems: overcoming the challenges and paving the way forward

Rheumatoid arthritis (RA) is a chronic inflammatory disorder of the articulating joints. Though considerable progress has been made in understanding the disease in the past 50 years, its pathogenesis remains unclear. The therapies for RA, such as nonsteroidal anti-inflammatory drugs, disease-modifying antirheumatic drugs, and glucocorticoids through conventional therapeutic delivery systems by percutaneous, intra-articular, intraperitoneal, oral, and intravenous administration, have shown their own disadvantages, which eventually reduce patient compliance for long-term therapy. Recently, drug delivery via a topical or transdermal route has gained attention as an alternative to the conventional approach. Though skin acts as a barrier for the delivery of drugs due to its structure, various permeation pathways are manipulated to enhance the drug delivery across or into the skin. However, poor skin retention is the reason for the failure of many conventional topical dosage forms, such as gels, sprays, and creams. Hence, there is an urgent need for conquering the skin boundary to improve skin partitioning. Nanotechnology is a developing and dynamic field gaining popularity in the nanoscale design. This review extensively describes the potential of various nanoformulations, such as vesicular systems, lipid nanoparticles, and polymeric nanoparticles, with a targeted approach to deliver the drugs to the inflamed joint region. Limelight has also been provided to next-generation approaches like surface modification, stimuli-responsive formulations, multifunctional carrier systems, microneedles, and microsponge systems. Physical methods for enhancing the transdermal delivery, such as electroporation and sonophoresis, and emerging treatment therapies, such as gene therapy, photothermal therapy, and photodynamic therapy, have been evaluated to enhance the treatment efficacy. The clinical status, patents and current challenges associated with nanotechnology and the future prospects of targeted drug delivery have also been discussed.

Lipid-based nanocarriers: an attractive approach for rheumatoid arthritis management

Lipid nanoparticles (LNPs) have emerged as transformative tools in modern drug delivery, offering unparalleled potential in enhancing the efficacy and safety of various therapeutics. In the context of rheumatoid arthritis (RA), a disabling autoimmune disorder characterized by chronic inflammation, joint damage, and limited patient mobility, LNPs hold significant promise for revolutionizing treatment strategies. LNPs offer several advantages over traditional drug delivery systems, including improved pharmacokinetics, enhanced tissue penetration, and reduced systemic toxicity. This article concisely summarizes the pathogenesis of RA, its associated risk factors, and therapeutic techniques and their challenges. Additionally, it highlights the noteworthy advancements made in managing RA through LNPs, including liposomes, niosomes, bilosomes, cubosomes, spanlastics, ethosomes, solid lipid nanoparticles, lipid micelles, lipid nanocapsules, nanostructured lipid carriers, etc. It also delves into the specific functional attributes of these nanocarrier systems, focusing on their role in treating and monitoring RA.

Polypropylene sulfide methotrexate nanoparticles target the synovial lymphatic system to restore immune tolerance in rheumatoid arthritis

Around 40 % of patients fail to achieve primary clinical outcomes for rheumatoid arthritis (RA). The growth of lymphatic system in the synovial membrane, is a primary response during RA inflammation. It is suggested that a delivery strategy targeting immunosuppressive agents to the synovial lymph nodes and then to the immune cells is beneficial for resolving arthritis. This study introduced a synthetic polypropylene sulfide methotrexate nano-delivery system (PPS-MTX), which was prepared by covalently bonding methotrexate to polypropylene sulfide, with a diameter size range of 36 nm. It enhanced joint accumulation and retention, which can be selectively uptake by antigen-presenting cells in the synovial lymphatic system. The results indicated that PPS-MTX nanoparticles effectively improved arthritis disease progression and restored the immune tolerance microenvironment in the synovial lymphatic system, promoting peripheral tolerance in collagen-induced arthritis mice. Additionally, no systemic toxicity was observed. This study presents a promising targeted strategy for inducing immune tolerance in the treatment of rheumatoid arthritis.

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.

Mesenchymal Stem Cell-Based Biomimetic Liposome for Targeted Treatment of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disorder that severely compromises joint health. The primary therapeutic strategy for advanced RA aims to inhibit joint inflammation. However, the nonspecific distribution of pharmacological agents has limited therapeutic efficacy and heightens the risks associated with RA treatment. To address this issue, we developed mesenchymal stem cell (MSC)-based biomimetic liposomes, termed MSCsome, which were composed of a fusion between MSC membranes and liposomes. MSC some with relatively simple preparation method effectively enhanced the targeting efficiency of drug to diseased joints. Interaction between lymphocyte function-associated antigen-1 and intercellular adhesion molecule-1 enhanced the affinity of the MSCsome for polarized macrophages, thereby improving its targeting capability to affected joints. The effective targeted delivery facilitated drug accumulation in joints, resulting in the significant inhibition of the inflammation, as well as protection and repair of the cartilage. In conclusion, this study introduced MSCsome as a promising approach for the effective treatment of advanced RA, providing a novel perspective on targeted drug delivery therapy for inflammatory diseases.

Lymphoid organ-targeted nanomaterials for immunomodulation of cancer, inflammation, and beyond

Nanomaterials exhibit significant potential for stimulating immune responses, offering both local and systemic modulation across a variety of diseases. The lymphoid organs, such as the spleen and lymph nodes, are home to various immune cells, including monocytes and dendritic cells, which contribute to both the progression and prevention/treatment of diseases. Consequently, many nanomaterial formulations are being rationally designed to target these organs and engage with specific cell types, thereby inducing therapeutic and protective effects. In this review, we explore crucial cellular interactions and processes involved in immune regulation and highlight innovative nano-based immunomodulatory approaches. We outline essential considerations in nanomaterial design with an emphasis on their impact on biological interactions, targeting capabilities, and treatment efficacy. Through selected examples, we illustrate the strategic targeting of therapeutically active nanomaterials to lymphoid organs and the subsequent immunomodulation for infection resistance, inflammation suppression, self-antigen tolerance, and cancer immunotherapy. Additionally, we address current challenges, discuss emerging topics, and share our outlook on future developments in the field.

Dual drug nanoparticle synergistically induced apoptosis, suppressed inflammation, and protected autophagic response in rheumatoid arthritis fibroblast-like synoviocytes

Rheumatoid arthritis (RA) is a chronic immune-mediated joint inflammatory disorder associated with aberrant activation of fibroblast-like synoviocytes (FLS). Recently, FLS gained importance due to its crucial role in RA pathogenesis, and thus, targeting FLS is suggested as an attractive treatment strategy for RA. FLS-targeted approaches may be combined with disease-modifying antirheumatic drugs (DMARDs) and natural phytochemicals to improve efficacy in RA control and negate immunosuppression. In this study, we assessed the therapeutic effectiveness of DD NP HG in primary RA-FLS cells isolated from the synovial tissue of FCA-induced RA rats. We observed that DD NP HG had good biosafety for healthy FLS cells and, at higher concentrations, a mild inhibitory effect on RA-FLS. The combination therapy (DD NP HG) of MTX NP and PEITC NE in RA-FLS showed a higher rate of apoptosis with significantly reduced LPS-induced expression of pro-inflammatory cytokines (TNF-α, IL-17A, and IL-6) in arthritic FLS. Further, the gene expression studies showed that DD NP HG significantly down-regulated the mRNA expression of IL-1β, RANKL, NFATc1, DKK1, Bcl-xl, Mcl-1, Atg12, and ULK1, and up-regulated the mRNA expression of OPG, PUMA, NOXA and SQSTM1 in LPS-stimulated RA-FLS cells. Collectively, our results demonstrated that DD NP HG significantly inhibited the RA-FLS proliferation via inducing apoptosis, down-regulating pro-inflammatory cytokines, and further enhancing the expression of genes associated with bone destruction in RA pathogenesis. A nanotechnology approach is a promising strategy for the co-delivery of dual drugs to regulate the RA-FLS function and achieve synergistic treatment of RA.

A Less-is-More Strategy for Mitochondria-Targeted Photodynamic Therapy of Rheumatoid Arthritis

Conventional photodynamic therapy (PDT) of rheumatoid arthritis (RA) faces a dilemma: low-power is insufficient to kill pro-inflammatory cells while high-power exacerbates inflammation. Herein, mitochondrial targeting is introduced in PDT of RA to implement a "less-is-more" strategy, where higher apoptosis in pro-inflammatory cells are achieved with lower laser power. In arthritic rats, chlorine 6-loaded and mitochondria-targeting liposomes (Ce6@M-Lip) passively accumulated in inflamed joints, entered pro-inflammatory macrophages, and actively localized to mitochondria, leading to enhanced mitochondrial dysfunction under laser irradiation. By effectively disrupting mitochondria, pro-inflammatory macrophages are more susceptible to PDT, resulting in increased apoptosis initiation. Additionally, it identifies that high-power irradiation caused cell rupture and release of endogenous danger signals that recruited and activated additional macrophages. In contrast, under low-power irradiation, mitochondria-targeting Ce6@M-Lip not only prevented inflammation but also reduced pro-inflammatory macrophage infiltration and pro-inflammatory cytokine secretion. Overall, targeting mitochondria reconciled therapeutic efficacy and inflammation, thus enabling efficacious yet inflammation-sparing PDT for RA. This highlights the promise of mitochondrial targeting to resolve the dilemma between anti-inflammatory efficacy and inflammatory exacerbation in PDT by implementing a "less-is-more" strategy.

Microenvironment Responsive Hydrogel Exerting Inhibition of Cascade Immune Activation and Elimination of Synovial Fibroblasts for Rheumatoid Arthritis Therapy

Rheumatoid arthritis (RA) is a progressive autoimmune disease and drug therapy has been restricted due to poor therapeutic efficacy and adverse effects. In RA synovium, dendritic cells present self-antigens to activate cascade immune pathway. Furthermore, downstream macrophages secrete high levels of pro-inflammatory cytokines; Hyperplasia of activated synovial fibroblasts (FLS) is responsible for hypoxic synovium microenvironment, secretion of cytokines/chemokines and erosion of bone/cartilage tissues. Positive feedback loop of inflammation between macrophages and FLS independent of antigen-presentation is constructed. Herein, an injectable pH-sensitive peptide hydrogel encapsulating siRNA/Methotrexate-polyethyleneimine (siMP, including sip65MP, sip38MP, siCD86MP) and Bismuthene nanosheet/Methotrexate-polyethyleneimine (BiMP) is successfully developed. Among them, siCD86MP reduces protein level of co-stimulatory molecule CD86 while sip65MP and sip38MP separately inhibit NF-κB and MAPK-p38 pathways of macrophages and FLS to suppress secretion of cytokines and MMPs. Meanwhile, reduction in anti-apoptotic property of FLS induced by inhibition of NF-κB pathway has a synergistic effect with photodynamic therapy (PDT) and photothermal therapy (PTT) mediated by BiMP for FLS elimination, effectively ameliorating hypoxic synovium microenvironment. After being injected into synovium, hydrogel responds to acidic microenvironment and serves as a reservoir for sustained drug release and inherent retention capacity of which enables cationic nanoparticles to bypass tissue barrier for precise synovium targeting. This brand-new drug delivery system combines modulating cascade immune pathway from beginning to end by RNAi and eliminating FLS for improving synovium microenvironment by phototherapy together, providing a robust strategy for clinical RA treatment.

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.

Autoantigenic Peptide and Immunomodulator Codelivery System for Rheumatoid Arthritis Treatment by Reestablishing Immune Tolerance

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by abnormal activation of CD4+ T cells and an imbalance of T helper 17 (Th17) and regulatory T (Treg) cells. Tolerogenic therapy via administration of self-antigens is a promising strategy for RA treatment, but delivery of autoantigens alone may exacerbate disease conditions. Current studies indicated that codelivery of autoantigens with immunomodulators can lead to a more tolerogenic immune response. Here, we constructed an autoantigen type II collagen peptide (CII250-270)- and immunomodulator leflunomide (LEF)-coloaded phosphatidylserine liposome vaccine (CII250-270-LEF-PSL) for RA treatment via induction of tolerant dendritic cells (tolDC) for further activation of Treg cells. The in vivo results showed that CII250-270-LEF-PSL can effectively induce tolDC, regulate the balance of Th1/Th2 and Th17/Treg, and reduce the secretion of pro-inflammatory cytokines (IFN-γ, IL-1β, and IL-17A) and IgG antibodies to inhibit synovial inflammation and bone erosion. Furthermore, our study also suggested that LEF regulated Th1 cell differentiation by inhibiting the activation of the JAK1/STAT1 signaling pathway, further alleviating RA. Overall, this work proved that the combination of autoantigenic peptides and immunomodulators was a promising modality for RA treatment by reestablishing antigen-specific immune tolerance, which also inspired additional insights into the development of combination therapies for the tolerability of RA.

Coassembly Nanomedicine Mediated by Intermolecular Interactions Between Methotrexate and Baricitinib for Improved Rheumatoid Arthritis Treatment

The combination of anti-rheumatoid arthritis (RA) drugs methotrexate (MTX) and baricitinib (BTN) has been reported to improve RA treatment efficacy. However, study on the strategy of combination is elusive when considering the benefit of the synergy between MTX and BTN. In this study, we found that the N-heterocyclic rings in the MTX and BTN offer hydrogen bonds and π-π stacking interactions, driving the formation of exquisite vesicular morphology of nanovesicles, denoted as MB NVs. The MB NVs with the MTX/BTN weight ratio of 2:1, MB NVs (2:1), showed an improved anti-RA effect through the synergy between the anti-inflammatory and antiproliferative responses. This work presents that the intermolecular interactions between drug molecules could mediate the coassembly behavior into nanomedicine as well as the therapy synergy both in vitro and in vivo, which may provide further understanding on the rational design of combination nanomedicine for therapeutic purposes.

Transdermally delivered tolerogenic nanoparticles induced effective immune tolerance for asthma treatment

Induction of antigen-specific immune tolerance for the treatment of allergic or autoimmune diseases is an attractive strategy. Herein, we investigated the protective effect of a transdermal microneedle patch against allergic asthma by stimulating allergen-specific immune tolerance. We fabricated biodegradable tolerogenic nanoparticles (tNPs) that are loaded with a model allergen ovalbumin (OVA) and an immunomodulator rapamycin, and filled the tNPs into microneedle tips by centrifugation to form sustained-release microneedles. After intradermal immunization, the microneedles successfully delivered the cargos into the skin and sustainedly released them for over 96 h. Importantly, the microneedles induced allergen-specific regulatory T cells (Treg), decreased the levels of pro-inflammatory cytokines and antibodies while increased anti-inflammation cytokines, finally leading to restored immune homeostasis. The lung tissue analysis illustrated that the sustained-release microneedles significantly reduced the infiltration of eosinophils, decreased the accumulation of mucus and collagen, and significantly relived asthma symptoms. Our results suggested that the sustained-release microneedle-based transdermal delivery system can induce antigen-specific immune tolerance with improved compliance and efficacy, providing a new therapeutic strategy for the treatment of allergic and autoimmune diseases.

Prodrug-based nanomedicines for rheumatoid arthritis

Most antirheumatic drugs with high toxicity exhibit a narrow therapeutic window due to their nonspecific distribution in the body, leading to undesirable side effects and reduced patient compliance. To in response to these challenges, prodrug-based nanoparticulate drug delivery systems (PNDDS), which combines prodrug strategy and nanotechnology into a single system, resulting their many advantages, including stability for prodrug structure, the higher drug loading capacity of the system, improving the target activity and bioavailability, and reducing their untoward effects. PNDDS have gained attention as a method for relieving arthralgia syndrome of rheumatoid arthritis in recent years. This article systematically reviews prodrug-based nanocarriers for rheumatism treatment, including Nano systems based on prodrug-encapsulated nanomedicines and conjugate-based nanomedicines. It provides a new direction for the clinical treatment of rheumatoid arthritis.

An Updated Review on Nanoemulsion: Factory for Food and Drug Delivery

BACKGROUND

A nanoemulsion is a colloidal system of small droplets dispersed in another liquid. It has attracted considerable attention due to its unique properties and various applications. Throughout this review, we provide an overview of nanoemulsions and how they can be applied to various applications such as drug delivery, food applications, and pesticide formulations.

OBJECTIVE

This updated review aims to comprehensively overview nanoemulsions and their applications as a versatile platform for drug delivery, food applications, and pesticide formulations.

METHODS

Research relevant scientific literature across various databases, including PubMed, Scopus, and Web of Science. Suitable keywords for this purpose include "nanoemulsion," "drug delivery," and "food applications." Ensure the search criteria include recent publications to ensure current knowledge is included.

RESULTS

Several benefits have been demonstrated in the delivery of drugs using nanoemulsions, including improved solubility, increased bioavailability, and controlled delivery. Nanoemulsions have improved some bioactive compounds in food applications, including vitamins and antioxidants. At the same time, pesticide formulations based on nanoemulsions have also improved solubility, shelf life, and effectiveness.

CONCLUSION

The versatility of nanoemulsions makes them ideal for drug delivery, food, and pesticide formulation applications. These products are highly soluble, bioavailable, and targeted, providing significant advantages. More research and development are required to implement nanoemulsion-based products on a commercial scale.

Immunomodulatory nano-preparations for rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease (AD) caused by the aberrant attack of the immune system on its own joint tissues. Genetic and environmental factors are the main reasons of immune system impairment and high incidence of RA. Although there are medications on the market that lessen disease activity, there is no known cure for RA, and patients are at risk in varying degrees of systemic immunosuppression. By transporting (encapsulating or surface binding) RA-related self-antigens, nucleic acids, immunomodulators, or cytokines, tolerogenic nanoparticles-also known as immunomodulatory nano-preparations-have the potential to gently regulate local immune responses and ultimately induce antigen-specific immune tolerance. We review the recent advances in immunomodulatory nano-preparations for delivering self-antigen or self-antigen plus immunomodulator, simulating apoptotic cell avatars in vivo, acting as artificial antigen-presenting cells, and based on scaffolds and gels, to provide a reference for developing new immunotherapies for RA.

Vaccines for immune tolerance against autoimmune disease

The high prevalence and rising incidence of autoimmune diseases have become a prominent public health issue. Autoimmune disorders result from the immune system erroneously attacking the body's own healthy cells and tissues, causing persistent inflammation, tissue injury, and impaired organ function. Existing treatments primarily rely on broad immunosuppression, leaving patients vulnerable to infections and necessitating lifelong treatments. To address these unmet needs, an emerging frontier of vaccine development aims to restore immune equilibrium by inducing immune tolerance to autoantigens, offering a potential avenue for a cure rather than mere symptom management. We discuss this burgeoning field of vaccine development against inflammation and autoimmune diseases, with a focus on common autoimmune disorders, including multiple sclerosis, type 1 diabetes, rheumatoid arthritis, inflammatory bowel disease, and systemic lupus erythematosus. Vaccine-based strategies provide a new pathway for the future of autoimmune disease therapeutics, heralding a new era in the battle against inflammation and autoimmunity.

A critical review of the novelties in the development of intravenous nanoemulsions

Nanoemulsions have gained increasing attention in recent years as a drug delivery system due to their ability to improve the solubility and bioavailability of poorly water-soluble drugs. This systematic review aimed to collect and critically analyze recent novelties in developing, designing, and optimizing intravenous nanoemulsions appearing in articles published between 2017 and 2022. The applied methodology involved searching two electronic databases PubMed and Scopus, using the keyword "nanoemulsion" in combination with "intravenous" or "parenteral". The resulting original articles were classified by the method of preparation into different categories. An overview of the current methods used for the preparation of such formulations, including high- and low-energy emulsification, was provided. The advantages and disadvantages of these methods were discussed, as well as their potential impact on the properties of the developed intravenous nanoemulsions. The problem of inconsistency in intravenous nanoemulsion terminology may lead to misunderstandings and misinterpretations of their properties and applications was also undertaken. Finally, the regulatory aspects of intravenous nanoemulsions, the state of the art in the field of intravenous emulsifiers, and the future perspectives were presented.

Advancement in nanotechnology for treatment of rheumatoid arthritis: scope and potential applications

Rheumatoid arthritis is a hyperactive immune disorder that results in severe inflammation in synovial joints, cartilage, and bone deterioration, resulting in immobilization of joints. Traditional approaches for the treatment of rheumatoid arthritis are associated with some limiting factors such as suboptimal patient compliance, inability to control the progression of disorder, and safety concerns. Therefore, innovative drug delivery carriers for efficient therapeutic delivery at inflamed synovial sites with better safety assessment are urgently needed to address these issues. From this perspective, nanotechnology is an outstanding alternative to traditional drug delivery approaches, and it has shown great promise in developing novel carriers to treat rheumatoid arthritis. Considering the current research and future application of nanocarriers, it is believed that nanocarriers can be a crucial element in rheumatoid arthritis treatment. This paper covers all currently available pathophysiological aspects of rheumatoid arthritis and treatment options. Future research for the reduction of synovial inflammation should focus on developing multifunction nanoparticles capable of delivering therapeutic agents with improved safety, efficacy, and cost-effectiveness to be commercialized.

Transition Metal-Based Therapies for Inflammatory Diseases

Inflammatory disease (ID) is a general term that covers all diseases in which chronic inflammation performs as the major manifestation of pathogenesis. Traditional therapies based on the anti-inflammatory and immunosuppressive drugs are palliative with the short-term remission. The emergence of nanodrugs has been reported to solve the potential causes and prevent recurrences, thus holding great potential for the treatment of IDs. Among various nanomaterial systems, transition metal-based smart nanosystems (TMSNs) with unique electronic structures possess therapeutic advantages owing to their large surface area to volume ratio, high photothermal conversion efficiency, X-ray absorption capacity, and multiple catalytic enzyme activities. In this review, the rationale, design principle, and therapeutic mechanisms of TMSNs for treatments of various IDs are summarized. Specifically, TMSNs can not only be designed to scavenge danger signals, such as reactive oxygen and nitrogen species and cell-free DNA, but also can be engineered to block the mechanism of initiating inflammatory responses. In addition, TMSNs can be further applied as nanocarriers to deliver anti-inflammatory drugs. Finally, the opportunities and challenges of TMSNs are discussed, and the future directions of TMSN-based ID treatment for clinical applications are emphasized.

Nanomaterials for antigen-specific immune tolerance therapy

Impairment of immune tolerance might cause autologous tissue damage or overactive immune response against non-pathogenic molecules. Although autoimmune disease and allergy have complicated pathologies, the current strategies have mainly focused on symptom amelioration or systemic immunosuppression which can lead to fatal adverse events. The induction of antigen-specific immune tolerance may provide therapeutic benefits to autoimmune disease and allergic response, while reducing nonspecific immune adverse responses. Diverse nanomaterials have been studied to induce antigen-specific immune tolerance therapy. This review will cover the immunological background of antigen-specific tolerance, clinical importance of antigen-specific immune tolerance, and nanomaterials designed for autoimmune and allergic diseases. As nanomaterials for modulating immune tolerances, lipid-based nanoparticles, polymeric nanoparticles, and biological carriers have been covered. Strategies to provide antigen-specific immune tolerance have been addressed. Finally, current challenges and perspectives of nanomaterials for antigen-specific immune tolerance therapy will be discussed.

Folate receptor-mediated targeted therapy for rheumatoid arthritis by methotrexate-phospholipid complex nano-emulsions

Rheumatoid arthritis (RA) is a common autoimmune and inflammatory disease. Activated macrophages in arthritic joints play a prominent role in the initiation and persistence of RA. Despite great progress in the clinical treatment of RA, poor response and high discontinuation due to systemic toxicity remain unsolved issues, especially the well-known methotrexate (MTX). Therefore, active targeted delivery of therapeutic drugs to pathogenic cells in arthritic joints is essential to increase in situ activity and decrease systemic toxicity. Here, we developed an MTX-loaded macrophage-targeted nano-emulsion (NE) based on the overexpression of folate receptor (FR) on activated macrophages, the inherent high affinity of FR for folate (FA), as well as the property of MTX and phospholipids to form complexes (MTX@PC). Intravenous injection of DID-labelled MTX@PC-FA NEs into adjuvant-induced arthritis (AIA) mice, in vivo images and flow cytometry results revealed that the NEs were highly targeted to inflamed joints and macrophages, respectively. Therapeutic studies suggested that this strategy was conducive to achieve high efficacy and low toxicity of MTX in the treatment of RA. Our research highlights MTX@PC-FA NEs as a potential treatment option for RA targeting the FR-expressed activated macrophages.

Exosome inspired photo-triggered gelation hydrogel composite on modulating immune pathogenesis for treating rheumatoid arthritis

Although exosome therapy has been recognized as a promising strategy in the treatment of rheumatoid arthritis (RA), sustained modulation on RA specific pathogenesis and desirable protective effects for attenuating joint destruction still remain challenges. Here, silk fibroin hydrogel encapsulated with olfactory ecto-mesenchymal stem cell-derived exosomes (Exos@SFMA) was photo-crosslinked in situ to yield long-lasting therapeutic effect on modulating the immune microenvironment in RA. This in situ hydrogel system exhibited flexible mechanical properties and excellent biocompatibility for protecting tissue surfaces in joint. Moreover, the promising PD-L1 expression was identified on the exosomes, which potently suppressed Tfh cell polarization via inhibiting the PI3K/AKT pathway. Importantly, Exos@SFMA effectively relieved synovial inflammation and joint destruction by significantly reducing T follicular helper (Tfh) cell response and further suppressing the differentiation of germinal center (GC) B cells into plasma cells. Taken together, this exosome enhanced silk fibroin hydrogel provides an effective strategy for the treatment of RA and other autoimmune diseases.

Therapeutic potential of tolerance-based peptide vaccines in autoimmune diseases

Autoimmune diseases are caused by the dysfunction of the body's immune regulatory system, which leads to the recognition of self-antigens and the destruction of self-tissues and is mediated by immune cells such as T and B cells, and affects 5-10% of the population worldwide. Current treatments such as non-steroidal anti-inflammatory drugs and glucocorticoids can only relieve symptoms of the disease and are accompanied by serious side effects that affect patient quality of life. The recent rise in antigen-specific therapies, especially vaccines carrying autoantigenic peptides, promises to change this disadvantage, where research has increased dramatically in the last decade. This therapy established specific immune tolerance by delivering peptide fragments containing disease-specific self-antigen epitopes to suppress excessive immune responses, thereby exerting a therapeutic effect, with high safety and specificity. This article presents the latest progress on the treatment of autoimmune diseases with autoantigen peptide vaccines. It includes the construction of peptide vaccine delivery system, the mechanism of inducing immune tolerance and its application.

Inflammation specific environment activated methotrexate-loaded nanomedicine to treat rheumatoid arthritis by immune environment reconstruction

Rheumatoid arthritis (RA), as an autoimmune inflammatory disease, is featured by enhanced vascular permeability, irreversible cartilage destroys and bone erosion. Although the pathogenesis of RA is still unclear, the immune environment, particularly the lymphatic system, which is instrumental to immune cell surveillance and interstitial fluid balance, plays vital roles in the process of RA. Herein, an inflammation specific environment activated methotrexate-encapsulated nanomedicine (MTX@NPs) was constructed for RA treatment, which accumulated in inflamed joints, and released MTX in the specific RA microenvironment. Notably, MTX@NPs could regulate the immune environment including reducing the expressions of inflammatory cytokines of macrophages and the inflammatory level of lymphatic epithelial cells (LECs), and ameliorating the lymphatic vessel contraction and drainage. In vitro and In vivo studies illustrated that MTX@NPs exhibited a high RA therapeutic efficacy and insignificant systemic toxicity owing to the suppression of the inflammation response and the improved lymphatic functions of RA joints. It suggests that the nanomedicine paves a potential way to the clinical practice of autoimmune diseases treatments via the regulation of immune environment and lymphatic functions. STATEMENT OF SIGNIFICANCE: Although 1.0% of the population in the world suffers from rheumatoid arthritis (RA), the pathogenesis of RA is still unclear and the therapeutic effect of the first-line clinical drugs is relatively low. Herein, we propose a specific RA-microenvironment triggered nanomedicine (MTX@NPs), which enhances RA treatment of a first-line antirheumatic drug (methotrexate, MTX) by immune environment reconstruction. The nanomedicine exhibits RA joints accumulation by EPR effect, and releases MTX under the specific RA environment, leading to the dramatical drop of M1-type macrophages and acceleration of lymphatic vessel contraction and drainage. Finally, the inflammatory cytokines in RA immune environment are reduced sharply, indicating the outstanding therapeutic efficacy of MTX@NPs to RA.

From vaccines to nanovaccines: A promising strategy to revolutionize rheumatoid arthritis treatment

Rheumatoid arthritis (RA) is a joint-related autoimmune disease that is difficult to cure. Most therapeutics act to alleviate the symptoms but not correct the causes of RA. Novel strategies that specifically target the causes are highly needed for RA management. Currently, early interruption of RA is increasingly suggested but the corresponding therapeutics are not available. Vaccines that have shown great success to combat infection, cancer, degenerative diseases, autoimmune diseases, etc. are ideal candidates for a new generation of anti-RA therapeutics to correct the causes and prevent RA or interrupt RA in early phases. Anti-RA vaccines can be divided into two major categories. One is to induce neutralizing antibodies and the other is to induce antigen-specific immune tolerance. The vaccines are inherently linked to nanotechnology because they usually need a biomacromolecule or carrier to provoke sufficient immune responses. In the past decade, designed nanocarriers such as nanoparticles, liposomes, nanoemulsion, etc., have been applied to optimize the vaccines for autoimmune disease treatment. Nanotechnology endows vaccines with a higher biostability, tunable in vivo behavior, better targeting, co-delivery with stimulatory agents, regulatory effects on immune responses, etc. In this review, unmet medical needs for RA treatment and anti-RA vaccinology are first introduced. The development of anti-RA therapies from vaccines to nanovaccines are then reviewed and perspectives on how nanotechnology promotes vaccine development and advancement are finally provided. In addition, challenges for anti-RA vaccine development are summarized and advantages of nanovaccines are analyzed. In conclusion, nanovaccines will be a promising strategy to revolutionize the treatment of RA by correcting the causes in an early phase of RA.

Radicals Scavenging MOFs Enabling Targeting Delivery of siRNA for Rheumatoid Arthritis Therapy

Macrophages play essential roles in the progression of rheumatoid arthritis (RA), which are polarized into the pro-inflammatory M1 phenotype with significant oxidative stress and cytokines excretion. Herein, an active targeting nanomedicine based on metal-organic frameworks (MOFs) to re-educate the diseased macrophages for RA therapy is reported. The MOFs are prepared via coordination between tannic acid (TA) and Fe³⁺ , and anti-TNF-α siRNA is loaded via a simple sonication process, achieving high loading capacity comparable to cationic vectors. The MOFs show excellent biocompatibility, and enable rapid endo/lysosome escape of siRNA via the proton-sponge effect for effective cytokines down-regulation. Importantly, such nanomedicine displays intrinsic radicals scavenging capability to eliminate a broad spectrum of reactive oxygen and nitrogen species (RONS), which in turn repolarizes the M1 macrophages into anti-inflammatory M2 phenotypes for enhanced RA therapy in combination with siRNA. The MOFs are further modified with bovine serum albumin (BSA) to allow cascade RA joint and diseased macrophages targeted delivery. As a result, an excellent anti-RA efficacy is achieved in a collagen-induced arthritis mice model. This work provides a robust gene vector with great translational potential, and offers a vivid example of rationally designing MOF structure with multifunctionalities to synergize with its payload for enhanced disease treatment.

Immune Modulation Using Extracellular Vesicles Encapsulated with MicroRNAs as Novel Drug Delivery Systems

Self-tolerance involves protection from self-reactive B and T cells via negative selection during differentiation, programmed cell death, and inhibition of regulatory T cells. The breakdown of immune tolerance triggers various autoimmune diseases, owing to a lack of distinction between self-antigens and non-self-antigens. Exosomes are non-particles that are approximately 50–130 nm in diameter. Extracellular vesicles can be used for in vivo cell-free transmission to enable intracellular delivery of proteins and nucleic acids, including microRNAs (miRNAs). miRNAs encapsulated in exosomes can regulate the molecular pathways involved in the immune response through post-transcriptional regulation. Herein, we sought to summarize and review the molecular mechanisms whereby exosomal miRNAs modulate the expression of genes involved in the immune response.