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.

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 over-expression 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-labeled 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.

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by persistent synovial inflammation and joint destruction. Insufficient apoptosis of fibroblast-like synoviocytes (FLSs) significantly contributes to the pathogenesis of RA by promoting hyperplasia and inflammatory cytokine secretion. Celastrol (CLT), a pentacyclic triterpene derived from Tripterygium wilfordii, has shown promise in inducing apoptosis via endoplasmic reticulum (ER) stress-mediated pathways. However, its clinical application is limited by poor solubility and off-target effects. Targeted delivery of CLT to FLSs and their ER could enhance therapeutic efficacy while minimizing toxicity. We engineered CLT-loaded, enzyme-responsive liposomes (CLT-FELipos) functionalized with hyaluronic acid (HA), oligopeptide GPA (for FAP-α recognition on FLSs), an ER-targeting KDEL peptide, and cleavable PEG chains. In vitro, CLT-FELipos were evaluated for FLS-specific uptake (via FAP-α/GPA and CD44/HA interactions), ER accumulation, and apoptosis induction. In vivo, adjuvant-induced arthritis (AIA) rats were treated with various formulations. Joint distribution was assessed using near-infrared imaging, and therapeutic efficacy was evaluated through measurements of paw swelling, histological analysis, and micro-CT for bone erosion. CLT-FELipos demonstrated selective binding to FAP-α on FLSs, followed by PEG cleavage and CD44-mediated cellular uptake. Confocal microscopy confirmed specific accumulation within the ER. In AIA rats, CLT-FELipos showed joint-specific distribution and effectively reduced FLS numbers in arthritic joints. Treatment with CLT-FELipos brought about inflammatory remission, bone erosion repair, and minimal adverse effects. Notably, CLT-FELipos caused minimal systemic toxicity, as evidenced by stable body weight and normal liver and kidney function tests results. CLT-FELipos represents a novel drug delivery system that specifically targets FLS and ER, which enhances CLT's therapeutic index in RA by inducing apoptosis in hyperplastic FLSs. The dual-targeting strategy (FAP-α/CD44 for FLSs and KDEL for ER) ensures precise drug delivery while reducing inflammation and joint destruction with improved safety. This innovative approach holds potential for RA treatment and warrants further clinical investigation.

Rheumatoid arthritis (RA) is a chronic autoimmune inflammation. Excessive proliferation and inadequate apoptosis of synovial macrophages are the crucial events of RA. Therefore, delivering therapeutic molecules to synovial macrophages specifically to tackle apoptotic insufficiency probably be an efficient way to reduce joint inflammation and bone erosion. Based on the characteristics of dextran sulfate (DS) specifically binding scavenger receptor A (SR-A) on macrophage and celastrol (CLT) inducing apoptosis, we designed synovial macrophage-targeted nano-emulsions encapsulated with CLT (SR-CLTNEs) and explored their anti-RA effect. After intravenous injection, fluorescence-labeled SR-CLTNEs successfully targeted inflammatory joints and synovial macrophages in a mouse model of RA, with the macrophage targeting efficiency of SR-CLTNEs, CLTNEs, and Free DID was 20.53%, 13.93%, and 9.8%, respectively. In vivo and in vitro studies showed that SR-CLTNEs effectively promoted the apoptosis of macrophages, reshaped the balance between apoptosis and proliferation, and ultimately treated RA in a high efficiency and low toxicity manner. Overall, our work demonstrates the efficacy of using SR-CLTNEs as a novel nanotherapeutic approach for RA therapy and the great translational potential of SR-CLTNEs.

Copper deficiency, commonly observed in myocardial infarction, leads to cardiomyocyte loss and cardiac dysfunction, yet the mechanism driving copper efflux remains unclear. To further elucidate the relationship between copper transporters and cardiac copper efflux during chronic myocardial ischemia, a rhesus monkey model was established by performing the permanent ligation of the left anterior descending coronary artery. A dramatic decrease in copper concentration within ischemic cardiomyocytes was observed alongside declining cardiac function. Among major copper transporters, COMMD1 and ATP7B were significantly upregulated in the ischemic myocardium. COMMD1 was specifically localised in cardiomyocytes undergoing copper efflux, whereas increased ATP7B was restricted to cardiac fibroblasts. This indicates that elevated COMMD1 regulates copper efflux in cardiomyocytes during chronic myocardial ischemia, functioning independently of its interactions with P‐type ATPase transporters. Given the discrepancy between RNA and protein levels of COMMD1 in ischemic myocardium, post‐translational modification is likely responsible for regulating COMMD1 expression. We found that the copper‐binding protein with E3 ubiquitin ligase activity, XIAP, augmented before the rise in COMMD1 expression within ischemic cardiomyocytes. Excessive XIAP specifically interacted with COMMD1 to enhance its protein levels under copper‐deprivation conditions and vice versa. Overall, our findings reveal a positive feedback loop among XIAP, COMMD1 and copper, highlighting the intricate interplay between XIAP and COMMD1 in regulating copper efflux in cardiomyocytes. This loop sets the stage for further investigation into therapeutic strategies to manage copper homeostasis in chronic myocardial ischemia.

Background: Rheumatoid arthritis (RA) is a systemic autoimmune disease (AD), and the global incidence rate is 0.5 ~ 1%. Existing medications might reduce symptoms, however, there is no known cure for this illness. Etanercept (EN) can competitively inhibit TNF-α binding to the TNF receptor on the cell surface to treat RA. However, subcutaneous injection of free EN predisposes to systemic distribution and induces immune system hypofunction. Draining lymph nodes (LNs) play a significant role in the onset, maintenance, and progression of RA as they are the primary sites of aberrant immune response and inflammatory cytokine production. Aim: The purpose of this study was to successfully treat RA with etanercept by encapsulating it in nanoemulsions (NEs/EN) and then delivering it specifically to draining LNs. The EN-loaded NEs were prepared by high-pressure homogenization method and modified with DSPE-mPEG2000 and Ca(OH)2. Methods: A novel nano-emulsion (NE) was constructed to deliver EN (NE/EN) to RA-draining LNs. To decrease aggregation and load EN, DSPE-mPEG2000 and Ca(OH)2 were successively decorated on the surface of the lipid injectable emulsions. The hydrodynamic diameter and morphology of NEs/EN were investigated by using a laser particle size analyzer and transmission electron microscopy, respectively. The in vivo fluorescence imaging system was used to study the in vivo LN targeting ability of the formulation. In the therapeutic experiment, NEs/EN was subcutaneously administrated to inhibit the development of the mouse arthritis model. Results: Circular dichroism spectrum and L929 cell experiment confirmed that NEs encapsulation had no impact on the biological activity of EN. In vivo investigation on collagen-induced arthritis (CIA) mouse model showed that NEs/EN have good inguinal lymph node targeting capabilities, as well as, anti-inflammatory effect against RA. Compared with the free group, the paw thickness and arthritic score in NEs/EN group were significantly alleviated. Moreover, the concentration of pro-inflammatory cytokines TNF-α and IL-1β in NEs/EN-treated mice was lower than that in free EN. Conclusion: NEs/EN effectively improve the effectiveness of EN in the treatment of RA. Our work provides an experimental foundation for expanding the clinical application of EN.