Targeted co-delivery biomimetic nanoparticles reverse macrophage polarization for enhanced rheumatoid arthritis therapy

Surface saturation of drug-loaded hollow manganese dioxide nanoparticles with human serum albumin for treating rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease accompanied by energy depletion and accumulation of reactive oxygen species (ROS). Inorganic nanoparticles (NPs) offer great promise for the treatment of RA because they mostly have functions beyond being drug carriers. However, conventional nanomaterials become coated with a protein corona (PC) or lose their cargo prematurely in vivo, reducing their therapeutic efficacy. To avoid these problems, we loaded methotrexate (MTX) into hollow structured manganese dioxide nanoparticles (H-MnO2 NPs), then coated them with a 'pseudo-corona' of human serum albumin (HSA) at physiological concentrations to obtain HSA-MnO2@MTX NPs. Efficacy of MTX, MnO2@MTX, and HSA-MnO2@MTX NPs was compared in vitro and in vivo. Compared to MnO2@MTX, HSA-coated NPs were taken up better by lipopolysaccharide-activated RAW264.7 and were more effective at lowering levels of pro-inflammatory cytokines and preventing ROS accumulation. HSA-MnO2@MTX NPs were also more efficient at blocking the proliferation and migration of fibroblast-like synoviocytes from rats with collagen-induced arthritis. In this rat model, HSA-MnO2@MTX NPs showed better biodistribution than other treatments, specifically targeting the ankle joint. Furthermore, HSA-MnO2@MTX NPs reduced swelling in the paw, regulated pro-inflammatory cytokine production, and limited cartilage degradation and signs of inflammation. These results establish the therapeutic potential of HSA-MnO2@MTX NPs against RA.

Nanotechnology-empowered combination therapy for rheumatoid arthritis: principles, strategies, and challenges

Rheumatoid arthritis (RA) is an autoimmune disease with multifactorial etiology and intricate pathogenesis. In RA, repeated monotherapy is frequently associated with inadequate efficacy, drug resistance, and severe side effects. Therefore, a shift has occurred in clinical practice toward combination therapy. However, conventional combination therapy encounters several hindrances, including low selectivity to arthritic joints, short half-lives, and varying pharmacokinetics among coupled drugs. Emerging nanotechnology offers an incomparable opportunity for developing advanced combination therapy against RA. First, it allows for co-delivering multiple drugs with augmented physicochemical properties, targeted delivery capabilities, and controlled release profiles. Second, it enables therapeutic nanomaterials development, thereby expanding combination regimens to include multifunctional nanomedicines. Lastly, it facilitates the construction of all-in-one nanoplatforms assembled with multiple modalities, such as phototherapy, sonodynamic therapy, and imaging. Thus, nanotechnology offers a promising solution to the current bottleneck in both RA treatment and diagnosis. This review summarizes the rationale, advantages, and recent advances in nano-empowered combination therapy for RA. It also discusses safety considerations, drug-drug interactions, and the potential for clinical translation. Additionally, it provides design tips and an outlook on future developments in nano-empowered combination therapy. The objective of this review is to achieve a comprehensive understanding of the mechanisms underlying combination therapy for RA and unlock the maximum potential of nanotechnology, thereby facilitating the smooth transition of research findings from the laboratory to clinical practice.

Advances in immunotherapy of M2 macrophages and gastrointestinal stromal tumor

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal-derived tumors of the GI tract. They can occur throughout the GI tract, and the survival time of some patients can be improved by first-line targeted therapy with imatinib. However, there are some limitations with imatinib treatment. Immunotherapy for GIST has attracted much attention in recent years, and as one of the most abundant cells in the GIST microenvironment, M2 macrophages play an important role in disease progression. They have unique anti-inflammatory and pro-tumorigenic effects and are one target for immunotherapy. This review summarizes the connection between different factors and the programmed death receptor-1/programmed death ligand-1 pathway and M2 macrophages to reactivate or enhance anti-tumor immunity and improve imatinib efficacy, and to provide new ideas for GIST immunotherapy.

In vivo Fate of Targeted Drug Delivery Carriers

This review aimed to systematically investigate the intracellular and subcellular fate of various types of targeting carriers. Upon entering the body via intravenous injection or other routes, a targeting carrier that can deliver therapeutic agents initiates their journey. If administered intravenously, the carrier initially faces challenges presented by the blood circulation before reaching specific tissues and interacting with cells within the tissue. At the subcellular level, the car2rier undergoes processes, such as drug release, degradation, and metabolism, through specific pathways. While studies on the fate of 13 types of carriers have been relatively conclusive, these studies are incomplete and lack a comprehensive analysis. Furthermore, there are still carriers whose fate remains unclear, underscoring the need for continuous research. This study highlights the importance of comprehending the in vivo and intracellular fate of targeting carriers and provides valuable insights into the operational mechanisms of different carriers within the body. By doing so, researchers can effectively select appropriate carriers and enhance the successful clinical translation of new formulations.

Inducing the "re-development state" of periodontal ligament cells via tuning macrophage mediated immune microenvironment

INTRODUCTION

Periodontal regeneration, specifically the restoration of the cementum-periodontal ligament (PDL)-alveolar bone complex, remains a formidable challenge in the field of regenerative dentistry. In light of periodontal development, harnessing the multi-tissue developmental capabilities of periodontal ligament cells (PDLCs) and reinitiating the periodontal developmental process hold great promise as an effective strategy to foster the regeneration of the periodontal complex.

OBJECTIVES

This study aims to delve into the potential effects of the macrophage-mediated immune microenvironment on the "developmental engineering" regeneration strategy and its underlying molecular mechanisms.

METHODS

In this study, we conducted a comprehensive examination of the periodontium developmental process in the rat mandibular first molar using histological staining. Through the induction of diverse immune microenvironments in macrophages, we evaluated their potential effects on periodontal re-development events using a cytokine array. Additionally, we investigated PDLC-mediated periodontal re-development events under these distinct immune microenvironments through transcriptome sequencing and relevant functional assays. Furthermore, the underlying molecular mechanism was also performed.

RESULTS

The activation of development-related functions in PDLCs proved challenging due to their declined activity. However, our findings suggest that modulating the macrophage immune response can effectively regulate PDLCs-mediated periodontium development-related events. The M1 type macrophage immune microenvironment was found to promote PDLC activities associated with epithelial-mesenchymal transition, fiber degradation, osteoclastogenesis, and inflammation through the Wnt, IL-17, and TNF signaling pathways. Conversely, the M2 type macrophage immune microenvironment demonstrated superiority in inducing epithelium induction, fibers formation, and mineralization performance of PDLCs by upregulating the TGFβ and PI3K-Akt signaling pathway.

CONCLUSION

The results of this study could provide some favorable theoretical bases for applying periodontal development engineering strategy in resolving the difficulties in periodontal multi-tissue regeneration.

pH-responsive size-adjustable liposomes induce apoptosis of fibroblasts and macrophages for rheumatoid arthritis treatment

In rheumatoid arthritis (RA), macrophages infiltrate joints, while fibroblast-like synovial cells proliferate abnormally, forming a barrier against drug delivery, which hinders effective drug delivery to joint focus. Here we firstly designed a pH-responsive size-adjustable nanoparticle, composed by methotrexate (MTX)-human serum albumin (HSA) complex coating with pH-responsive liposome (Lipo/MTX-HSA) for delivering drugs specifically to inflamed joints in acidic environments. We showed in vitro that the nanoparticles can induce mitochondrial dysfunction, promote apoptosis of fibroblast-like synoviocytes and macrophages, further reduce the secretion of inflammatory factors (TNF-α, IL-1β, MMP-9), and regulate the inflammatory microenvironment. We also demonstrated similar effects in a rat model of arthritis, in which Lipo/MTX-HSA accumulated in arthritic joints, and at low pH, liposome phospholipid bilayer cleavage released small-sized MTX-HSA, which effectively reduced the number of fibroblast-synoviocytes and macrophages in joints, alleviated joint inflammation, and repaired bone erosion. These findings suggest that microenvironment-responsive size-adjustable nanoparticles show promise as a treatment against rheumatoid arthritis. STATEMENT OF SIGNIFICANCE: Abnormal proliferation of fibroblast synoviocytes poses a physical barrier to effective nanoparticle delivery. We designed size-adjustable nano-delivery systems by preparing liposomes with cholesterol hemisuccinate (CHEM), which were subsequently loaded with small-sized albumin nanoparticles encapsulating the cytotoxic drug MTX (MTX-HSA), termed Lipo/MTX-HSA. Upon tail vein injection, Lipo/MTX-HSA could be aggregated at the site of inflammation via the ELVIS effect in the inflamed joint microenvironment. Specifically, intracellular acidic pH-triggered dissociation of liposomes promoted the release of MTX-HSA, which was further targeted to fibroblasts or across fibroblasts to macrophages to exert anti-inflammatory effects. The results showed that liposomes with adjustable particle size achieved efficient drug delivery, penetration and retention in joint sites; the strategy exerted significant anti-inflammatory effects in the treatment of rheumatoid arthritis by inducing mitochondrial dysfunction to promote apoptosis in fibrosynoviocytes and macrophages.

Microenvironmental Enzyme-Responsive Methotrexate Modified Quercetin Micelles for the Treatment of Rheumatoid Arthritis

Purpose

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease involving synovial inflammation and joint destruction. Although therapeutic drugs for RA have some efficacy, they usually cause severe side effects and are expensive. RA is characterized by synovial hyperplasia, intra-articular hypoxia, upregulated expression of matrix metalloproteinases, and excessive accumulation of reactive oxygen species. The adverse microenvironment further aggravates activated macrophage infiltration. Therefore, controlling the microenvironment of diseased tissues and targeting the activated macrophages have become new therapeutic targets in RA patients.

Methods

Here, microenvironment-targeting micelles (PVGLIG-MTX-Que-Ms) were synthesized using the thin film hydration method. In the inflammatory microenvironment, PVGLIG was cleaved by the highly expressed MMP-2, PEG5000 was eliminated, MTX was exposed, macrophage activation was targeted, and Que enrichment was enhanced. The cytotoxicity, targeting, antioxidant, and anti-inflammatory properties of drug-loaded micelles were tested in vitro. The drug-loaded micelles were used to treat CIA rats. In vivo targeting, expression of serum inflammatory factors, immunohistochemistry of the articular cartilage, and changes in immunofluorescence staining were observed.

Results

The developed micelles had a particle size of (89.62 ±1.33) nm and a zeta potential of (-4.9 ±0.53) mV. The IC50 value of PVGLIG-MTX-Que-Ms (185.90 ±6.98) μmol/L was significantly lower than that of free Que (141.10 ±6.39) μmol/L. The synthesized micelles exhibited slow-release properties, low cytotoxicity, strong targeting abilities, and significant anti-inflammatory effects in vitro. In vivo, the drug-loaded micelles accumulated at the joint site for a long time. PVGLIG-MTX-Que-Ms significantly reduced joint swelling, improved bone destruction, and decreased the expression of serum inflammatory factors in CIA rats.

Conclusion

The smart-targeting micelles PVGLIG-MTX-Que-Ms with strong targeting, anti-inflammatory, cartilage-protective, and other multiple positive effects are a promising new tool for RA treatment.

Reproducible Synthesis of Biocompatible Albumin Nanoparticles Designed for Intra-articular Administration of Celecoxib to Treat Osteoarthritis

Osteoarthritis (OA) is the most common form of arthritis, with intra-articular (IA) delivery of therapeutics being the current best option to treat pain and inflammation. However, IA delivery is challenging due to the rapid clearance of therapeutics from the joint and the need for repeated injections. Thus, there is a need for long-acting delivery systems that increase the drug retention time in joints with the capacity to penetrate OA cartilage. As pharmaceutical utility also demands that this is achieved using biocompatible materials that provide colloidal stability, our aim was to develop a nanoparticle (NP) delivery system loaded with the COX-2 inhibitor celecoxib that can meet these criteria. We devised a reproducible and economical method to synthesize the colloidally stable albumin NPs loaded with celecoxib without the use of any of the following conditions: high temperatures at which albumin denaturation occurs, polymer coatings, oils, Class 1/2 solvents, and chemical protein cross-linkers. The spherical NP suspensions were biocompatible, monodisperse with average diameters of 72 nm (ideal for OA cartilage penetration), and they were stable over 6 months at 4 °C. Moreover, the NPs loaded celecoxib at higher levels than those required for the therapeutic response in arthritic joints. For these reasons, they are the first of their kind. Labeled NPs were internalized by primary human articular chondrocytes cultured from the knee joints of OA patients. The NPs reduced the concentration of inflammatory mediator prostaglandin E2 released by the primaries, an indication of retained bioactivity following NP synthesis. Similar results were observed in lipopolysaccharide-stimulated human THP-1 monocytes. The IA administration of these NPs is expected to avoid side-effects associated with oral administration of celecoxib and to maintain a high local concentration in the knee joint over a sustained period. They are now ready for evaluation by IA administration in animal models of OA.

Inflammation-Targeted Drug Delivery Strategies via Albumin-Based Systems

Albumin, being the most abundant serum protein, has the potential to significantly enhance the physicochemical properties of therapeutic payloads, thereby improving their pharmacological effects. Apart from its passive transport via the enhanced permeability and retention effect, albumin can actively accumulate in tumor microenvironments or inflammatory tissues via receptor-mediated processes. This unique property makes albumin a promising scaffold for targeted drug delivery. This review focuses on exploring different delivery strategies that combine albumin with drug payloads to achieve targeted therapy for inflammatory diseases. Also, albumin-derived therapeutic products on the market or undergoing clinical trials in the past decade have been summarized to gain insight into the future development of albumin-based drug delivery systems. Given the involvement of inflammation in numerous diseases, drug delivery systems utilizing albumin demonstrate remarkable advantages, including enhanced properties, improved in vivo behavior and efficacy. Albumin-based drug delivery systems have been demonstrated in clinical trials, while more advanced strategies for improving the capacity of drug delivery systems with the help of albumin remain to be discovered. This could pave the way for biomedical applications in more effective and precise treatments.

Development and challenges of antimicrobial peptide delivery strategies in bacterial therapy: A review

The escalating global prevalence of antimicrobial resistance poses a critical threat, prompting concerns about its impact on public health. This predicament is exacerbated by the acute shortage of novel antimicrobial agents, a scarcity attributed to the rapid surge in bacterial resistance. This review delves into the realm of antimicrobial peptides, a diverse class of compounds ubiquitously present in plants and animals across various natural organisms. Renowned for their intrinsic antibacterial activity, these peptides provide a promising avenue to tackle the intricate challenge of bacterial resistance. However, the clinical utility of peptide-based drugs is hindered by limited bioavailability and susceptibility to rapid degradation, constraining efforts to enhance the efficacy of bacterial infection treatments. The emergence of nanocarriers marks a transformative approach poised to revolutionize peptide delivery strategies. This review elucidates a promising framework involving nanocarriers within the realm of antimicrobial peptides. This paradigm enables meticulous and controlled peptide release at infection sites by detecting dynamic shifts in microenvironmental factors, including pH, ROS, GSH, and reactive enzymes. Furthermore, a glimpse into the future reveals the potential of targeted delivery mechanisms, harnessing inflammatory responses and intricate signaling pathways, including adenosine triphosphate, macrophage receptors, and pathogenic nucleic acid entities. This approach holds promise in fortifying immunity, thereby amplifying the potency of peptide-based treatments. In summary, this review spotlights peptide nanosystems as prospective solutions for combating bacterial infections. By bridging antimicrobial peptides with advanced nanomedicine, a new therapeutic era emerges, poised to confront the formidable challenge of antimicrobial resistance head-on.

Global scientific trends update on macrophage polarization in rheumatoid arthritis: A bibliometric and visualized analysis from 2000 to 2022

The goal of this work was to use bibliometric analysis to help guide future research on macrophage polarization in RA. We looked for studies on macrophage polarization in RA published between January 1, 2000, and December 31, 2022, in the WoSCC database. Research trends and hotspots were shown and assessed using VOSviewer and CiteSpace. A total of 181 articles were gathered. Belgium was among the early adopters of the field. Chinese institutes have produced the most research. Researchers such as Angel Luis Corb, Amaya Puig-Kröger, and Lizbeth Estrada-Capetillo have made major contributions to the field. Frontiers in Immunology has published the most study findings. According to VOSviewer, the most investigated immune cells, biomarkers, and signaling pathways in the previous three years have been "T cells", "gm-csf", and "nf-κb" in that order. We discovered that the most often used terms in the previous three years were "pathway", "oxidative stress", "extracellular capsule" and "nlrp3 inflammasome" using Citespace. We emphasize these concepts in our findings, presenting the exact mechanisms of pathophysiology related to macrophage polarization in RA, as well as current breakthroughs in therapy strategies.

Lonicerin alleviates the progression of experimental rheumatoid arthritis by downregulating M1 macrophages through the NF-κB signaling pathway

The present study aimed to evaluate anti-rheumatoid arthritis (RA) effect of Lonicerin (LON), a safe compound with anti-inflammatory and immunomodulatory properties. Nevertheless, the exact role of LON in RA remains elusive. In this test, the anti-RA effect of LON was evaluated in collagen-induced arthritis (CIA) mouse model. Relevant parameters were measured during the experiment; ankle tissue and serum were collected at the end of the experiment for radiology, histopathology, and inflammation analysis. ELISA, qRT-PCR, immunofluorescence, and western blot were used to explore the effect of LON on the polarization of macrophages and related signal pathways. It was discovered that LON treatment attenuated the disease progression of CIA mice with lower paw swelling, clinical score, mobility, and inflammatory response. LON treatment significantly decreased M1 marker levels in CIA mice and LPS/IFN-γ-induced RAW264.7 cells, while slightly increasing M2 marker levels in CIA mice and IL-4-induced RAW264.7 cells. Mechanistically, LON attenuated the activation of the NF-κB signaling pathway, which contributes to M1 macrophage polarization and inflammasome activation. In addition, LON inhibited NLRP3 inflammasome activation in M1 macrophages, thereby reducing inflammation by inhibiting IL-1β and IL-18 release. These results indicated that LON might exert anti-RA effects by regulating the polarization of M1/M2 macrophage, especially by inhibiting macrophage polarization toward M1.

Human Serum Albumin Based Nanodrug Delivery Systems: Recent Advances and Future Perspective

With the success of several clinical trials of products based on human serum albumin (HSA) and the rapid development of nanotechnology, HSA-based nanodrug delivery systems (HBNDSs) have received extensive attention in the field of nanomedicine. However, there is still a lack of comprehensive reviews exploring the broader scope of HBNDSs in biomedical applications beyond cancer therapy. To address this gap, this review takes a systematic approach. Firstly, it focuses on the crystal structure and the potential binding sites of HSA. Additionally, it provides a comprehensive summary of recent progresses in the field of HBNDSs for various biomedical applications over the past five years, categorized according to the type of therapeutic drugs loaded onto HSA. These categories include small-molecule drugs, inorganic materials and bioactive ingredients. Finally, the review summarizes the characteristics and current application status of HBNDSs in drug delivery, and also discusses the challenges that need to be addressed for the clinical transformation of HSA formulations and offers future perspectives in this field.

Research Advances in Nucleic Acid Delivery System for Rheumatoid Arthritis Therapy

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that affects the lives of nearly 1% of the total population worldwide. With the understanding of RA, more and more therapeutic drugs have been developed. However, lots of them possess severe side effects, and gene therapy may be a potential method for RA treatment. A nanoparticle delivery system is vital for gene therapy, as it can keep the nucleic acids stable and enhance the efficiency of transfection in vivo. With the development of materials science, pharmaceutics and pathology, more novel nanomaterials and intelligent strategies are applied to better and safer gene therapy for RA. In this review, we first summarized the existing nanomaterials and active targeting ligands used for RA gene therapy. Then, we introduced various gene delivery systems for RA treatment, which may enlighten the relevant research in the future.

Combining nanotechnology with monoclonal antibody drugs for rheumatoid arthritis treatments

Rheumatoid arthritis (RA) is a systemic immune disease characterized by synovial inflammation. Patients with RA commonly experience significant damage to their hand and foot joints, which can lead to joint deformities and even disability. Traditional treatments have several clinical drawbacks, including unclear pharmacological mechanisms and serious side effects. However, the emergence of antibody drugs offers a promising approach to overcome these limitations by specifically targeting interleukin-1 (IL-1), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and other cytokines that are closely related to the onset of RA. This approach reduces the incidence of adverse effects and contributes to significant therapeutic outcomes. Furthermore, combining these antibody drugs with drug delivery nanosystems (DDSs) can improve their tissue accumulation and bioavailability.Herein, we provide a summary of the pathogenesis of RA, the available antibody drugs and DDSs that improve the efficacy of these drugs. However, several challenges need to be addressed in their clinical applications, including patient compliance, stability, immunogenicity, immunosupression, target and synergistic effects. We propose strategies to overcome these limitations. In summary, we are optimistic about the prospects of treating RA with antibody drugs, given their specific targeting mechanisms and the potential benefits of combining them with DDSs.

Messenger Nanozyme for Reprogramming the Microenvironment of Rheumatoid Arthritis

Dysregulation of superoxide anion (O₂^-) and hydrogen peroxide (H₂O₂) metabolism in the microenvironment of rheumatoid arthritis (RA) drives the feedback loops of TNF-α and IL-1β thereby inducing an inflammatory storm between immune cells and joint tissue cells. Here, we combine nanoscale manganese dioxide (MnO₂) with microvesicles derived from macrophage (MMV). The former possesses superoxide dismutase (SOD) and catalase (CAT)-like activities that can modulate this imbalance, and we amplify the enzyme-like activities by using the amorphous hollow mesoporous structure and surface modification. The latter is a natural endogenous component with the parent cell-like inflammatory homing ability and a unique function of transmitting information to surrounding and distant cells (″messenger function″), which helps amorphous hollow MnO₂ (H-MnO₂) nanozymes to cloak in the blood and reach the site of inflammation, where they can not only accumulate in activated macrophages but also pretend to be ″messengers″ that are utilized by fibroblast-like synoviocytes (FLS) and chondrocytes. In addition, we also load dexamethasone sodium phosphate (DSP) for helping the nanozymes work. Messenger nanozyme (MMV-MnO₂@DSP) inherits the natural properties of MMV and mimics the enzymatic activity of SOD and CAT. It accumulates in activated macrophages to restore the metabolism of O₂^- and H₂O₂ while promoting repolarization and inhibits the feedback loops of TNF-α and IL-1β among macrophages, fibroblast-like synoviocytes, and chondrocytes, leading to anti-rheumatoid arthritis effects in vitro and in vivo.

Nano-Based Co-Delivery System for Treatment of Rheumatoid Arthritis

A systemic autoimmune condition known as rheumatoid arthritis (RA) has a significant impact on patients’ quality of life. Given the complexity of RA’s biology, no single treatment can totally block the disease’s progression. The combined use of co-delivery regimens integrating various diverse mechanisms has been widely acknowledged as a way to make up for the drawbacks of single therapy. These days, co-delivery systems have been frequently utilized for co-treatment, getting over drug limitations, imaging of inflammatory areas, and inducing reactions. Various small molecules, nucleic acid drugs, and enzyme-like agents intended for co-delivery are frequently capable of producing the ability to require positive outcomes. In addition, the excellent response effect of phototherapeutic agents has led to their frequent use for delivery together with chemotherapeutics. In this review, we discuss different types of nano-based co-delivery systems and their advantages, limitations, and future directions. In addition, we review the prospects and predicted challenges for the combining of phototherapeutic agents with conventional drugs, hoping to provide some theoretical support for future in-depth studies of nano-based co-delivery systems and phototherapeutic agents.

Xanthones from Securidaca inappendiculata Hassk. attenuate collagen-induced arthritis in rats by inhibiting the nicotinamide phosphoribosyltransferase/glycolysis pathway and macrophage polarization

Securidaca inappendiculata (SI) Hassk. is a traditional medicine used to treat rheumatoid arthritis. Recent studies have reported that macrophages are the primary regulators of joint homeostasis and their polarization is closely related to their metabolic mode. Here, we aimed to investigate the relationship between the joint protective effect of SI's xanthone-rich fraction (XRF) on collagen-induced arthritis (CIA) in rats and the nicotinamide phosphoribosyltransferase (NAMPT)-glycolysis-polarization axis of macrophages. CIA model rats were treated with oral XRF and therapeutic efficacy was assessed based on arthritis score, degree of paw swelling, histological examination, and immunohistochemical analysis. Serum levels of cytokines, cellular metabolite concentrations, and protein and mRNA expression were determined by enzyme-linked immunosorbent assay (ELISA), western blotting (WB), and quantitative real-time PCR (RT-qPCR), respectively. The effects of dihydroxy-3,4-dimethoxyxanthone (XAN), a representative SI-derived compound, on RAW264.7 macrophages was analyzed in vitro using confocal laser scanning and flow cytometry. We found that XRF treatment significantly alleviated disease severity in CIA model rats. Levels of pro-inflammatory cytokines in the serum and M1 markers in synovium were reduced after XRF treatment, accompanied by an increase in the levels of anti-inflammatory cytokines and M2 markers. Further, XRF significantly suppressed synovial glycolysis by regulating NAMPT. In vitro studies further showed that XAN induced repolarization of lipopolysaccharide (LPS)-induced RAW264.7 macrophages with M1-M2 phenotype. Moreover, XAN negatively regulated glycolysis in the LPS-induced RAW264.7 macrophages in correlation with changes in NAMPT expression. Overall, the findings of this study suggest that the joint protective effects of XRF are achieved by inhibiting the NAMPT/glycolysis pathway and thereby regulating macrophage polarization.

Natural medicines of targeted rheumatoid arthritis and its action mechanism

Rheumatoid arthritis (RA) is an autoimmune disease involving joints, with clinical manifestations of joint inflammation, bone damage and cartilage destruction, joint dysfunction and deformity, and extra-articular organ damage. As an important source of new drug molecules, natural medicines have many advantages, such as a wide range of biological effects and small toxic and side effects. They have become a hot spot for the vast number of researchers to study various diseases and develop therapeutic drugs. In recent years, the research of natural medicines in the treatment of RA has made remarkable achievements. These natural medicines mainly include flavonoids, polyphenols, alkaloids, glycosides and terpenes. Among them, resveratrol, icariin, epigallocatechin-3-gallate, ginsenoside, sinomenine, paeoniflorin, triptolide and paeoniflorin are star natural medicines for the treatment of RA. Its mechanism of treating RA mainly involves these aspects: anti-inflammation, anti-oxidation, immune regulation, pro-apoptosis, inhibition of angiogenesis, inhibition of osteoclastogenesis, inhibition of fibroblast-like synovial cell proliferation, migration and invasion. This review summarizes natural medicines with potential therapeutic effects on RA and briefly discusses their mechanisms of action against RA.

Recent progress in therapeutic strategies and biomimetic nanomedicines for rheumatoid arthritis treatment

INTRODUCTION

Rheumatoid arthritis (RA) is an autoimmune systemic disease in which inflammatory and immune cells accumulate in inflamed joints. Researchers aimed at the characteristics of RA to achieve the effect of treating RA through different therapeutic strategies, and have used various endogenous materials to design drug-loaded nanoparticles that can target RA by binding to cell adhesion molecules or chemokines. In some cases, the nanoparticles can respond to the characteristics of the microenvironment.

AREAS COVERED

This article reviews the recent advances in the treatment of RA from two aspects of therapeutic strategies and delivery strategies. Therapeutic strategies mainly include neutralization of inflammatory factors, promotion of inflammatory cell apoptosis, ROS scavenger, immunosuppression, and bone tissue repair. The drug delivery strategy is mainly described from two aspects: chemically functionalized biomimetic nanoparticles and endogenous nanoparticles.

EXPERT OPINION

Biomimetic NPs may be effective drug carriers for targeted RA treatment. NPs can reduce the clearance of mononuclear phagocytes, prolong the blood circulation time, and improve the targeting ability. With the deepening of research, more and more biomimetic NPs have entered the clinical trial stage. However, safe and scalable preparation methods are needed to improve their clinical applicability.