Sinomenine suppresses collagen-induced arthritis by reciprocal modulation of regulatory T cells and Th17 cells in gut-associated lymphoid tissues

Sinomenine Alleviates Rheumatoid Arthritis by Suppressing the PI3K-Akt Signaling Pathway, as Demonstrated Through Network Pharmacology, Molecular Docking, and Experimental Validation

Purpose

Sinomenine (SIN) is commonly used in Traditional Chinese Medicine (TCM) as a respected remedy for rheumatoid arthritis (RA). Nevertheless, the therapeutic mechanism of SIN in RA remains incompletely understood. This study aimed to delve into the molecular mechanism of SIN in the treatment of RA.

Methods

The potential targets of SIN were predicted using the TCMSP server, STITCH database, and SwissTarget Prediction. Differentially expressed genes (DEGs) in RA were obtained from the GEO database. Enrichment analyses and molecular docking were conducted to explore the potential mechanism of SIN in the treatment of RA. In vitro and in vivo studies were conducted to validate the intervention effects of SIN on rheumatoid arthritis, as determined through network pharmacology analyses.

Results

A total of 39 potential targets associated with the therapeutic effects of SIN in RA were identified. Enrichment analysis revealed that these potential targets are primarily enriched in PI3K-Akt signaling pathway, and the molecular docking suggests that SIN may act on specific proteins in the pathway. Experimental results have shown that exposure to SIN inhibits cytokine secretion, promotes apoptosis, reduces metastasis and invasion, and blocks the activation of the PI3K-Akt signaling pathway in RA fibroblast-like synoviocytes (RA-FLS). Moreover, SIN treatment alleviated arthritis-related symptoms and regulated the differentiation of CD4+ T cells in the spleen of collagen-induced arthritis (CIA) mice.

Conclusion

By utilizing network pharmacology, molecular modeling, and in vitro/in vivo validation, this study demonstrates that SIN can alleviate RA by inhibiting the PI3K-Akt signaling pathway. These findings enhance the understanding of the therapeutic mechanisms of SIN in RA, offering a stronger theoretical foundation for its future clinical application.

Antioxidant Activity and the Therapeutic Effect of Sinomenine Hydrochloride-Loaded Liposomes-in-Hydrogel on Atopic Dermatitis

Sinomenine hydrochloride is an excellent drug with anti-inflammatory, antioxidant, immune-regulatory, and other functions. Atopic dermatitis is an inherited allergic inflammation that causes itchiness, redness, and swelling in the affected area, which can have a significant impact on the life of the patient. There are many therapeutic methods for atopic dermatitis, and sinomenine with immunomodulatory activity might be effective in the treatment of atopic dermatitis. In this study, the atopic dermatitis model was established in experimental mice, and physical experiments were carried out on the mice. In the experiment, sinomenine hydrochloride liposomes-in-hydrogel as a new preparation was selected for delivery. In this case, liposomes were dispersed in the colloidal hydrogel on a mesoscopic scale and could provide specific transfer properties. The results showed that the sinomenine hydrochloride-loaded liposomes-in-hydrogel system could effectively inhibit atopic dermatitis.

Qualitative and quantitative analysis of chemical constituents in goupi plaster prepared by various extraction methods using UPLC-Q-Exactive-MS and UPLC-MS/MS

Goupi plaster, a representative preparation of black plaster, has demonstrated promising effects in treating knee osteoarthritis. However, high temperature used in traditional frying extraction may cause decomposition of its effective components, thus limiting the efficacy. This study aimed to explore the scientific nature of the traditional preparation technology of Goupi plaster, and to compare the effects of different extraction methods on the types of chemical components and the content of index components. The UPLC-Q-Exactive-MS and UPLC-MS/MS technologies which have high efficiency, sensitivity and accuracy, were used to qualitatively and quantitatively analyze the chemical components of Goupi plaster under different preparation processes. The results show that the extraction solvent approach is different from the traditional frying extraction method, and has a positive effect. However, the mechanism of action of Goupi plaster is complex and its pharmacological effects are diverse. Future studies should explore whether it necessary to change the frying extraction method. This experiment provides a theoretical basis that will guide further scientific discussion and research into the frying extraction of Goupi plaster.

Sinomenine increases osteogenesis in mice with ovariectomy-induced bone loss by modulating autophagy

BACKGROUND

A decreased autophagic capacity of bone marrow mesenchymal stromal cells (BMSCs) has been suggested to be an important cause of decreased osteogenic differentiation. A pharmacological increase in autophagy of BMSCs is a potential therapeutic option to increase osteoblast viability and ameliorate osteoporosis.

AIM

To explore the effects of sinomenine (SIN) on the osteogenic differentiation of BMSCs and the underlying mechanisms.

METHODS

For in vitro experiments, BMSCs were extracted from sham-treated mice and ovariectomized mice, and the levels of autophagy markers and osteogenic differentiation were examined after treatment with the appropriate concentrations of SIN and the autophagy inhibitor 3-methyladenine. In vivo, the therapeutic effect of SIN was verified by establishing an ovariectomy-induced mouse model and by morphological and histological assays of the mouse femur.

RESULTS

SIN reduced the levels of AKT and mammalian target of the rapamycin (mTOR) phosphorylation in the phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR signaling pathway, inhibited mTOR activity, and increased autophagy ability of BMSCs, thereby promoting the osteogenic differentiation of BMSCs and effectively alleviating bone loss in ovariectomized mice in vivo.

CONCLUSION

The Chinese medicine SIN has potential for the treatment of various types of osteoporosis, bone homeostasis disorders, and autophagy-related diseases.

A systematic review: Sinomenine

Sinomenine (SIN), an alkaloid derived from the traditional Chinese medicine, Caulis Sinomenii, has been used as an anti-inflammatory drug in China for over 30 years. With the continuous increase in research on the pharmacological mechanism of SIN, it has been found that, in addition to the typical rheumatoid arthritis (RA) treatment, SIN can be used as a potentially effective therapeutic drug for anti-tumour, anti-renal, and anti-nervous system diseases. By reviewing a large amount of literature and conducting a summary analysis of the literature pertaining to the pharmacological mechanism of SIN, we completed a review that focused on SIN, found that the current research is insufficient, and offered an outlook for future SIN development. We hope that this review will increase the public understanding of the pharmacological mechanisms of SIN, discover SIN research trial shortcomings, and promote the effective treatment of immune diseases, inflammation, and other related diseases.

Sinomenine attenuates pulmonary fibrosis by downregulating TGF-β1/Smad3, PI3K/Akt and NF-κB signaling pathways

BACKGROUND

Since COVID-19 became a global epidemic disease in 2019, pulmonary fibrosis (PF) has become more prevalent among persons with severe infections, with IPF being the most prevalent form. In traditional Chinese medicine, various disorders are treated using Sinomenine (SIN). The SIN's strategy for PF defense is unclear.

METHODS

Bleomycin (BLM) was used to induce PF, after which inflammatory factors, lung histological alterations, and the TGF-/Smad signaling pathway were assessed. By administering various dosages of SIN and the TGF- receptor inhibitor SB-431,542 to human embryonic lung fibroblasts (HFL-1) and A549 cells, we were able to examine proliferation and migration as well as the signaling molecules implicated in Epithelial-Mesenchymal Transition (EMT) and Extra-Cellular Matrix (ECM).

RESULTS

In vivo, SIN reduced the pathological changes in the lung tissue induced by BLM, reduced the abnormal expression of inflammatory cytokines, and improved the weight and survival rate of mice. In vitro, SIN inhibited the migration and proliferation by inhibiting TGF-β1/Smad3, PI3K/Akt, and NF-κB pathways, prevented the myofibroblasts (FMT) of HFL-1, reversed the EMT of A549 cells, restored the balance of matrix metalloenzymes, and reduced the expression of ECM proteins.

CONCLUSION

SIN attenuated PF by down-regulating TGF-β/Smad3, PI3K/Akt, and NF-κB signaling pathways, being a potential effective drug in the treatment of PF.

Sinomenine ameliorates fibroblast-like synoviocytes dysfunction by promoting phosphorylation and nuclear translocation of CRMP2

ETHNOPHARMACOLOGICAL RELEVANCE

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by synovial inflammation and arthritic pain. Sinomenine (SIN), derived from the rhizome of Chinese medical herb Qing Teng (scientific name: Sinomenium acutum (Thunb.) Rehd. Et Wils), has a longstanding use in Chinese traditional medicine for treating rheumatoid arthritis. It has been shown to possess anti-inflammatory, analgesic, and immunosuppressive effects with minimal side-effects clinically. However, the mechanisms governing its effects in treatment of joint pathology, especially on fibroblast-like synoviocytes (FLSs) dysfunction, and arthritic pain remains unclear.

AIM

This study aimed to investigate the effect and underlying mechanism of SIN on arthritic joint inflammation and joint FLSs dysfunctions.

MATERIALS AND METHODS

Collagen-induced arthritis (CIA) was induced in rats and the therapeutic effects of SIN on joint pathology were evaluated histopathologically. Next, we conducted a series of experiments using LPS-induced FLSs, which were divided into five groups (Naïve, LPS, SIN 10, 20, 50 μg/ml). The expression of inflammatory factors was measured by qPCR and ELISA. The invasive ability of cells was detected by modified Transwell assay and qPCR. Transwell migration and cell scratch assays were used to assess the migration ability of cells. The distribution and content of relevant proteins were observed by immunofluorescence and laser confocal microscopy, as well as Western Blot and qPCR. FLSs were transfected with plasmids (CRMP2 T514A/D) to directly modulate the post-translational modification of CRMP2 protein and downstream effects on FLSs function was monitored.

RESULTS

SIN alleviated joint inflammation in rats with CIA, as evidenced by improvement of synovial hyperplasia, inflammatory cell infiltration and cartilage damage, as well as inhibition of pro-inflammatory cytokines release from FLSs induced by LPS. In vitro studies revealed a concentration-dependent suppression of SIN on the invasion and migration of FLSs induced by LPS. In addition, SIN downregulated the expression of cellular CRMP2 that was induced by LPS in FLSs, but increased its phosphorylation at residue T514. Moreover, regulation of pCRMP2 T514 by plasmids transfection (CRMP2 T514A/D) significantly influenced the migration and invasion of FLSs. Finally, SIN promoted nuclear translocation of pCRMP2 T514 in FLSs.

CONCLUSIONS

SIN may exert its anti-inflammatory and analgesic effects by modulating CRMP2 T514 phosphorylation and its nuclear translocation of FLSs, inhibiting pro-inflammatory cytokine release, and suppressing abnormal invasion and migration. Phosphorylation of CRMP2 at the T514 site in FLSs may present a new therapeutic target for treating inflammatory joint's destruction and arthritic pain in RA.

Pharmacological mechanisms of sinomenine in anti-inflammatory immunity and osteoprotection in rheumatoid arthritis: A systematic review

BACKGROUND

Sinomenine (SIN) is the main pharmacologically active component of Sinomenii Caulis and protects against rheumatoid arthritis (RA). In recent years, many studies have been conducted to elucidate the pharmacological mechanisms of SIN in the treatment of RA. However, the molecular mechanism of SIN in RA has not been fully elucidated.

PURPOSE

To summarize the pharmacological effects and molecular mechanisms of SIN in RA and clarify the most valuable regulatory mechanisms of SIN to provide clues and a basis for basic research and clinical applications.

METHODS

We systematically searched SciFinder, Web of Science, PubMed, China National Knowledge Internet (CNKI), the Wanfang Databases, and the Chinese Scientific Journal Database (VIP). We organized our work based on the PRISMA statement and selected studies for review based on predefined selection criteria.

OUTCOME

After screening, we identified 201 relevant studies, including 88 clinical trials and 113 in vivo and in vitro studies on molecular mechanisms. Among these studies, we selected key results for reporting and analysis.

CONCLUSIONS

We found that most of the known pharmacological mechanisms of SIN are indirect effects on certain signaling pathways or proteins. SIN was manifested to reduce the release of inflammatory cytokines such as Tumor necrosis factor-α (TNF-α), Interleukin-6 (IL-6), and IL-1β, thereby reducing the inflammatory response, and apparently blocking the destruction of bone and cartilage. The regulatory effects on inflammation and bone destruction make SIN a promising drug to treat RA. More notably, we believe that the modulation of α7nAChR and the regulation of methylation levels at specific GCG sites in the mPGES-1 promoter by SIN, and its mechanism of directly targeting GBP5, certainly enriches the possibilities and the underlying rationale for SIN in the treatment of inflammatory immune-related diseases.

Traditional Chinese Medicine in Osteoporosis Intervention and the Related Regulatory Mechanism of Gut Microbiome

The gut microbiome (GM) has become a crucial factor that can affect the progression of osteoporosis. A number of studies have demonstrated the impact of Traditional Chinese Medicine (TCM) on GM and bone metabolism. In this review, we summarize the potential mechanisms of the relationship between osteoporosis and GM disorder and introduce several natural Chinese medicines that exert anti-osteoporosis effects by modulating the GM. It is underlined that, through the provision of the microbial associated molecular pattern (MAMP), the GM causes inflammatory reactions and alterations in the Treg-Th17 balance and ultimately leads to changes in bone mass. Serotonin and many hormones, especially estrogen, may play a crucial role in the interaction of the GM with bone metabolism. Additionally, the GM may affect the absorption of specific nutrients in the intestine, particularly minerals like calcium, magnesium, and phosphorus. Several natural Chinese herbs, such as Sambucus Williamsii, Achyranthes bidentata Blume, Pleurotus ostreatus and Ganoderma lucidum mushrooms, Pueraria Lobata, and Agaricus blazei Murill have exhibited anti-osteoporosis effects through regulating the distribution and metabolism of the GM. These herbs may increase the abundance of Firmicutes, decrease the abundance of Bacteroides, promote the GM to produce more SCFAs, modulate the immune response caused by harmful bacteria, and increase the proportion of Treg-Th17 to indirectly affect bone metabolism. Moreover, gut-derived 5-HT is an important target for TCM to prevent osteoporosis via the gut-bone axis. Puerarin could prevent osteoporosis by improving intestinal mucosal integrity and decrease systemic inflammation caused by estrogen deficiency.

Rheumatoid Arthritis Has Won the Battle but Not the War: How Many Joints Will We Save Tomorrow?

Rheumatoid arthritis refers to joint diseases of unclear etiology whose final stages can lead to unbearable pain and complete immobility of the affected joints. As one of the most widely known diseases of the joints, it serves as a study target for a large number of research groups and pharmaceutical companies. Modern treatment with anti-inflammatory drugs, including janus kinase (JAK) inhibitors, monoclonal antibodies, and botanicals (polyphenols, glycosides, alkaloids, etc.) has achieved some success and hope for improving the course of the disease. However, existing drugs against RA have a number of side effects which push researchers to elaborate on more selective and effective drug candidates. The avant-garde of research, which aims to develop treatment of rheumatoid arthritis using antisense oligonucleotides along with nonsteroidal drugs and corticosteroids against inflammation, increases the chances of success and expands the arsenal of drugs. The primary goal in the treatment of this disease is to find therapies that allow patients with rheumatoid arthritis to move their joints without pain. The main purpose of this review is to show the victories and challenges for the treatment of rheumatoid arthritis and the tortuous but promising path of research that aims to help patients experience the joy of freely moving joints without pain.

Sinomenine ameliorates rheumatoid arthritis by modulating tryptophan metabolism and activating aryl hydrocarbon receptor via gut microbiota regulation

Gut microbiota dysbiosis is associated with the development of rheumatoid arthritis (RA). Sinomenine (SIN) is an effective immunosuppressive and anti-inflammatory drug used for treating RA, but how SIN regulates gut microbiota to alleviate RA remains underexplored. To identify the critical gut microbial species and microbial metabolites associated with the RA-protective effects of SIN, the microbiota-dependent anti-RA effects of SIN were assessed by 16S rRNA gene sequencing, antibiotic treatment, and fecal microbiota transplantation. Metabolomics analysis, transcriptional analysis, and targeted bacteria/metabolites gavage were conducted to explore how SIN regulates gut microbiota to reduce the severity of RA. SIN could restore intestinal microbial balance by mainly modulating the abundance of Lactobacillus, and significantly relieve collagen-induced arthritis (CIA) symptoms in a gut microbiota-dependent manner. SIN significantly elevated microbial tryptophan metabolites indole-3-acrylic acid (IA), indole-3-propionic acid (IPA), and indole-3-acetic acid (IAA). Tryptophan metabolites supplementation could activate aryl hydrocarbon receptor (AhR) and regulate Th17/Treg balance in CIA rats. Intriguingly, SIN relieved the arthritis symptoms involving the enrichment of two beneficial anti-CIA Lactobacillus species, L. paracasei and L. casei by mono-colonization. The promising therapeutic function of SIN was mostly attributed to the activation of AhR by explicitly targeting the Lactobacillus and microbial tryptophan metabolites. The intestinal bacterium L. paracasei and L. casei may be used to reduce the severity of CIA.

Fecal microbiota transplantation improves chicken growth performance by balancing jejunal Th17/Treg cells

BACKGROUND

Intestinal inflammation has become a threatening concern in chicken production worldwide and is closely associated with Th17/Treg cell imbalance. Several studies described that gut microbiota is significantly implicated in chicken growth by modulating intestinal immune homeostasis and immune cell differentiation. Whether reshaping gut microbiota by fecal microbiota transplantation (FMT) could improve chicken growth by balancing Th17/Treg cells is an interesting question.

RESULTS

Here, the chickens with significantly different body weight from three different breeds (Turpan cockfighting × White Leghorn chickens, white feather chickens, and yellow feather chickens) were used to compare Th17 and Treg cells. qPCR and IHC staining results indicated that Th17 cell-associated transcriptional factors Stat3 and rorγt and cytokines IL-6, IL-17A, and IL-21 were significantly (P < 0.05) higher in the jejunum of low body weight chickens, while Treg cell-associated transcriptional factor foxp3 and cytokines TGF-β and IL-10 were significantly (P < 0.05) lower in the jejunum of low body weight chickens, indicating imbalanced Th17/Treg cells were closely related to chicken growth performance. Transferring fecal microbiota from the healthy donor with better growth performance and abundant Lactobacillus in feces to 1-day-old chicks markedly increased growth performance (P < 0.001), significantly decreased Th17 cell-associated transcriptional factors and cytokines, and increased Treg cell-associated transcriptional factors and cytokines in the jejunum (P < 0.05). Furthermore, FMT increased the abundance of Lactobacillus (FMT vs Con; 84.98% vs 66.94%). Besides, the metabolites of tryptophan including serotonin, indole, and 5-methoxyindoleacetate were increased as well, which activated their receptor aryl-hydrocarbon-receptor (AhR) and expressed more CYP1A2 and IL-22 to maintain Th17/Treg cell balance and immune homeostasis.

CONCLUSION

These findings suggested that imbalanced Th17/Treg cells decreased chicken growth performance, while FMT-reshaped gut microbiota, i.e., higher Lactobacilli, increased chicken growth performance by balancing Th17/Treg cells. Video Abstract.

A review on pharmacokinetics of sinomenine and its anti-inflammatory and immunomodulatory effects

Autoimmune diseases (ADs), with significant effects on morbidity and mortality, are a broad spectrum of disorders featured by body's immune responses being directed against its own tissues, resulting in chronic inflammation and tissue damage. Sinomenine (SIN) is an alkaloid isolated from the root and stem of Sinomenium acutum which is mainly used to treat pain, inflammation and immune disorders for centuries in China. Its potential anti-inflammatory role for treating immune-related disorders in experimental animal models and in some clinical applications have been reported widely, suggesting an inspiring application prospect of SIN. In this review, the pharmacokinetics, drug delivery systems, pharmacological mechanisms of action underlying the anti-inflammatory and immunomodulatory effects of SIN, and the possibility of SIN as adjuvant to disease-modifying anti-rheumatic drugs (DMARDs) therapy were summarized and evaluated. This paper aims to reveal the potential prospects and limitations of SIN in the treatment of inflammatory and immune diseases, and to provide ideas for compensating its limitations and reducing the side effects, and thus to make SIN better translate to the clinic.

Sinomenine regulates immune cell subsets: Potential neuro-immune intervene for precise treatment of chronic pain

Chronic pain is a disease of long-lasting pain with unpleasant feelings mediated by central and (or) peripheral sensitization, its duration usually lasts more than 3 months or longer than the expected recovery time. The patients with chronic pain are manifested with enhanced sensitivity to noxious and non-noxious stimuli. Due to an incomplete understanding of the mechanisms, patients are commonly insensitive to the treatment of first line analgesic medicine in clinic. Thus, the exploration of non-opioid-dependent analgesia are needed. Recent studies have shown that "sinomenine," the main active ingredient in the natural plant "sinomenium acutum (Thunb.) Rehd. Et Wils," has a powerful inhibitory effect on chronic pain, but its underlying mechanism still needs to be further elucidated. A growing number of studies have shown that various immune cells such as T cells, B cells, macrophages, astrocytes and microglia, accompanied with the relative inflammatory factors and neuropeptides, are involved in the pathogenesis of chronic pain. Notably, the interaction of the immune system and sensory neurons is essential for the development of central and (or) peripheral sensitization, as well as the progression and maintenance of chronic pain. Based on the effects of sinomenine on immune cells and their subsets, this review mainly focused on describing the potential analgesic effects of sinomenine, with rationality of regulating the neuroimmune interaction.

Recent Advancements in Drug Delivery of Sinomenine, A Disease-Modifying Anti-Rheumatic Drug

Sinomenine (SIN) is a benzyltetrahydroisoquinoline-type alkaloid isolated from the dried plant root and stem of Sinomenium acutum (Thumb.) Rehd.et Wils, which shows potent anti-inflammatory and analgesic effects. As a transforming disease-modifying anti-rheumatic drug, SIN has been used to treat rheumatoid arthritis over twenty-five years in China. In recent years, SIN is also in development for use against other disorders, including colitis, pain, traumatic brain injury, and uveitis. However, its commercial hydrochloride (SIN-HCl) shows low oral bioavailability and certain allergic reactions in patients, due to the release of histamine. Therefore, a large number of pharmaceutical strategies have been explored to address these liabilities, such as prolonging release behaviors, enhancing skin permeation and adsorption for transdermal delivery, targeted SIN delivery using new material or conjugates, and co-amorphous technology. This review discusses these different delivery strategies and approaches employed to overcome the limitations of SIN for its efficient delivery, in order to achieve improved bioavailability and reduced side effects. The potential advantages and limitations of SIN delivery strategies are elaborated along with discussions of potential future SIN drug development strategies.

Towards Better Sinomenine-Type Drugs to Treat Rheumatoid Arthritis: Molecular Mechanisms and Structural Modification

Sinomenine is the main component of the vine Sinomenium acutum. It was first isolated in the early 1920s and has since attracted special interest as a potential anti-rheumatoid arthritis (RA) agent, owing to its successful application in traditional Chinese medicine for the treatment of neuralgia and rheumatoid diseases. In the past few decades, significant advances have broadened our understanding of the molecular mechanisms through which sinomenine treats RA, as well as the structural modifications necessary for improved pharmacological activity. In this review, we summarize up-to-date reports on the pharmacological properties of sinomenine in RA treatment, document their underlying mechanisms, and provide an overview of promising sinomenine derivatives as potential RA drug therapies.

The bone-protective mechanisms of active components from TCM drugs in rheumatoid arthritis treatment

Rheumatoid arthritis (RA) is an autoimmune disease whose hallmarks are synovial inflammation and irreversible bone destruction. Bone resorption resulting from osteoclasts involves the whole immune and bone systems. Breakdown of bone remodeling is attributed to overactive immune cells that produce large quantities of cytokines, upregulated differentiation of osteoclasts with enhanced resorptive activities, suppressed differentiation of osteoblasts, invading fibroblasts and microbiota dysbiosis. Despite the mitigation of inflammation, the existing treatment in Western medicine fails to prevent bone loss during disease progression. Traditional Chinese medicine (TCM) has been used for thousands of years in RA treatment, showing great efficacy in bone preservation. The complex components from the decoctions and prescriptions exhibit various pharmacological activities. This review summarizes the research progress that has been made in terms of the bone-protective effect of some representative compounds from TCM drugs and proposes the substantial mechanisms involved in bone metabolism to provide some clues for future studies. These active components systemically suppress bone destruction via inhibiting joint inflammation, osteoclast differentiation, and fibroblast proliferation. Neutrophil, gut microenvironment and microRNA has been proposed as future focus.

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.

An Apriori Algorithm-Based Association Analysis of Analgesic Drugs in Chinese Medicine Prescriptions Recorded From Patients With Rheumatoid Arthritis Pain

Chronic pain, a common symptom of people with rheumatoid arthritis, usually behaves as persistent polyarthralgia pain and causes serious damage to patients' physical and mental health. Opioid analgesics can lead to a series of side effects like drug tolerance and addiction. Thus, seeking an alternative therapy and screening out the corresponding analgesic drugs is the key to solving the current dilemma. Traditional Chinese Medicine (TCM) therapy has been recognized internationally for its unique guiding theory and definite curative effect. In this study, we used the Apriori Algorithm to screen out potential analgesics from 311 cases that were treated with compounded medication prescription and collected from “Second Affiliated Hospital of Zhejiang Chinese Medical University” in Hangzhou, China. Data on 18 kinds of clinical symptoms and 16 kinds of Chinese herbs were extracted based on this data mining. We also found 17 association rules and screened out four potential analgesic drugs—“Jinyinhua,” “Wugong,” “Yiyiren,” and “Qingfengteng,” which were promised to help in the clinical treatment. Besides, combined with System Cluster Analysis, we provided several different herbal combinations for clinical references.

Quercetin Impedes Th17 Cell Differentiation to Mitigate Arthritis Involving PPARγ-Driven Transactivation of SOCS3 and Redistribution Corepressor SMRT from PPARγ to STAT3

SCOPE

Quercetin (QU) is one of the most abundant flavonoids in plants and has attracted the attention of researchers because of its remarkable antirheumatoid arthritis (RA) effects and extremely low adverse reactions. However, the underlying mechanism needs further study.

METHODS AND RESULTS

Flow cytometry, immunofluorescence, enzyme linked immunosorbent assay （ELISA）, and quantitative real-time polymerase chain reaction （qRT-PCR） reveal the obvious inhibitory effects of QU on Th17 cell differentiation in arthritic mice. More importantly, QU markedly limits the development of Th17 cell polarization, which is virtually compromised by the treatment with peroxisome proliferator activated receptor γ (PPARγ) inhibitor GW9662 and knockdown of PPARγ. Additionally, molecular dynamics simulation and immunofluorescence exhibit QU directly binds to PPARγ and increases PPARγ nuclear translocation. Besides, QU confers its moderation effect on suppressor of cytokine signaling protein (SOCS3)/signal transducer and activator of transcription 3 (STAT3) axis partially depending on PPARγ. Furthermore, coimmunoprecipitation shows QU redistributes the corepressor silencing mediator for retinoid and thyroid-hormone receptors (SMRT) from PPARγ to STAT3. Finally, the inhibition of Th17 response and the antiarthritic effect of QU are nullified by GW9662 treatment in arthritic mice.

CONCLUSION

QU targets PPARγ and consequently inhibits Th17 cell differentiation by dual inhibitory activity of STAT3 to exert antiarthritic effect. The findings facilitate its development and put forth a stage for uncovering the mechanism of other naturally occurring compounds with chemical structures similar to QU.

Anti-inflammatory natural products as potential therapeutic agents of rheumatoid arthritis: A systematic review

BACKGROUND

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease causing severe locomotor disability and deterioration in the quality of life. Existing treatments for RA mainly focus on the use of immunomodulators and the suppression of synovial inflammation, and many have significant side effects. Medicinal plants are regarded as important alternative sources for treating RA.

PURPOSE

This review summarizes the bioactive compounds of medicinal plants, which have been shown to modulate the immune response by regulating interleukins in vitro and in vivo experimental models, and that may be promising substances for use in the treatment of RA.

METHODS

Articles on natural products used for the management of arthritis were retrieved from PubMed, Embase, Scopus, and Web of Science through electronic and manual search in English. In total, 576 publications were identified, and 34 were included in this systematic review.

RESULTS

Two articles presented findings on the role of natural components in the treatment of arthritis in both in vitro and in vivo studies. Nine reports defined the role of plant-derived natural molecules in the treatment of arthritis using cell lines, and 27 in vivo studies assessed the anti-arthritic efficacy and immunomodulation effects of phytoconstituents on interleukin production and inflammatory responses.

CONCLUSION

This systematic review broadly reports that, in contrast to other classes of phytochemicals, flavonoids have the greatest therapeutic potential against arthritis by modulating the expression of pro-inflammatory TNF-α, IL-1β, IL-6, IL-8, and IL-17, as well as anti-inflammatory IL-2 and IL-10 cytokines, through the suppression of dynamic inflammatory biomarkers.

Sinomenine Relieves Airway Remodeling By Inhibiting Epithelial-Mesenchymal Transition Through Downregulating TGF-β1 and Smad3 Expression In Vitro and In Vivo

Airway remodeling is associated with dysregulation of epithelial-mesenchymal transition (EMT) in patients with asthma. Sinomenine (Sin) is an effective, biologically active alkaloid that has been reported to suppress airway remodeling in mice with asthma. However, the molecular mechanisms behind this effect remain unclear. We aimed to explore the potential relationship between Sin and EMT in respiratory epithelial cells in vitro and in vivo. First, 16HBE cells were exposed to 100 μg/mL LPS and treated with 200 μg/mL Sin. Cell proliferation, migration, and wound healing assays were performed to evaluate EMT, and EMT-related markers were detected using Western blotting. Mice with OVA-induced asthma were administered 35 mg/kg or 75 mg/kg Sin. Airway inflammation and remodeling detection experiments were performed, and EMT-related factors and proteins in the TGF-β1 pathway were detected using IHC and Western blotting. We found that Sin suppressed cell migration but not proliferation in LPS-exposed 16HBE cells. Sin also inhibited MMP7, MMP9, and vimentin expression in 16HBE cells and respiratory epithelial cells from mice with asthma. Furthermore, it decreased OVA-specific IgE and IL-4 levels in serum, relieved airway remodeling, attenuated subepithelial collagen deposition, and downregulating TGF-β1and Smad3 expression in mice with asthma. Our results suggest that Sin suppresses EMT by inhibiting IL-4 and downregulating TGF-β1 and Smad3 expression.

Sinomenine hydrochloride ameliorates dextran sulfate sodium-induced colitis in mice by modulating the gut microbiota composition whilst suppressing the activation of the NLRP3 inflammasome

Sinomenine is a pure alkaloid that can be isolated from the root of Sinomenium acutum and has been found to exert anti-inflammatory and immunosuppressive effects. The present study investigated the effects of sinomenine hydrochloride (SIN) on inflammation and the gut microbiota composition in the colon of mouse models of dextran sulfate sodium (DSS)-induced colitis. DSS-induced mice colitis was established by treating the mice with drinking water containing 3% (w/v) DSS for 7 days. The disease activity index of each mouse was calculated on a daily basis. All mice were sacrificed on day 11, then the weight of their spleen and length of their colons were measured. The histological analysis was measured by hematoxylin-eosin staining. Oral administration of SIN (100 mg/kg/day) attenuated the DSS-induced increases in the disease activity indices and spleen indices, DSS-induced shortening of the colon length and histological damage. In addition, reverse transcription-quantitative PCR data showed that SIN treatment effectively regulated the expression of inflammatory mediators, specifically by suppressing the expression of proinflammatory gene (TNF-α, IL-6 and inducible nitric oxide synthase) whilst increasing those associated with inhibiting inflammation (IL-10 and arginine 1). Gut microbiota analysis was conducted using 16S ribosomal DNA sequencing. The results revealed that SIN improved bacterial community homeostasis and diversity, which were damaged by DSS. Furthermore, western blotting showed that the activation of the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome was markedly suppressed by SIN treatment. In conclusion, these results indicated that SIN may ameliorate experimental colitis by modulating the gut microbiota composition and suppressing the activation of the NLRP3 inflammasome in mice. Overall, these findings suggested a broad protective effect of SIN in treating inflammatory gut diseases, including ulcerative colitis.

Co-amorphous systems of sinomenine with nonsteroidal anti-inflammatory drugs: A strategy for solubility improvement, sustained release, and drug combination therapy against rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune joint disorder that affects about 1% of the world population and may lead to severe disability and comorbidity. Despite breakthroughs in past decades to understand its pathogenesis and the development of transforming disease-modifying antirheumatic drugs, the symptoms of many patients are not substantially improved. Sinomenine (SIN), a natural alkaloid with poor solubility, has been used to treat RA in China for years because of its unique immunoregulative activity. However, its commercial hydrochloride form has a short half-time, which may cause huge fluctuations of blood drug concentration leading to severe adverse reactions. In this study, co-amorphous systems of SIN with three nonsteroidal anti-inflammatory drugs (NSAIDs), including indomethacin, naproxen, and sulindac, were prepared for the combination therapy, as well as the improvement of its aqueous solubility and controlled release. Each co-amorphous sample was characterized by powder X-ray diffraction (PXRD), temperature-modulated differential scanning calorimetry (mDSC), and Fourier transform infrared spectroscopy (FTIR). The CO₂^- and N⁺H stretching vibration in the three co-amorphous samples appears in FTIR spectra, suggesting the formation of salts between SIN and NSAIDs. SIN also exhibits sustained release rates in all three co-amorphous samples. These co-amorphous systems show excellent physicochemical stability because no recrystallization was observed at 25 °C and 75% relative humidity (RH) after four months. Our study suggests that SIN-NSAIDs co-amorphous systems represent an affordable and promising treatment against RA.

The Role of Chronic Inflammation in Various Diseases and Anti-inflammatory Therapies Containing Natural Products

Chronic inflammation represents a long-term reaction of the body's immune system to noxious stimuli. Such a sustained inflammatory response sometimes results in lasting damage to healthy tissues and organs. In fact, chronic inflammation is implicated in the development and progression of various diseases, including cardiovascular diseases, respiratory diseases, metabolic diseases, neurodegenerative diseases, and even cancers. Targeting nonresolving inflammation thus provides new opportunities for treating relevant diseases. In this review, we will go over several chronic inflammation-associated diseases first with emphasis on the role of inflammation in their pathogenesis. Then, we will summarize a number of natural products that exhibit therapeutic effects against those diseases by acting on different markers in the inflammatory response. We envision that natural products will remain a rich resource for the discovery of new drugs treating diseases associated with chronic inflammation.

Sinomenine protects bone from destruction to ameliorate arthritis via activating p62Thr269/Ser272-Keap1-Nrf2 feedback loop

Disease-modifying antirheumatic drugs (DMARDs) are the first line medications to treat rheumatoid arthritis (RA), a chronic and systemic autoimmune disease affecting multiple joints. Sinomenine (SIN) is thought a natural DMARD (nDMARD) and effectively utilized to treat RA in clinic for several decades in China. Here we reported that it is not methotrexate (MTX), a representative drug of DMARDs, but SIN protected joints from destruction to alleviate the symptoms of the mice with arthritis, indicating that the underlying mechanism of SIN is different from MTX to treat arthritis. Due to the dominate role of synovium fibroblasts in the joint destruction of arthritis, we applied synovium fibroblasts derived from RA patients (RASFs) to investigate the anti-arthritic effect and explore the underlying mechanism of SIN. We found that SIN significantly inhibited the secretion of IL-6 and IL-33 and ROS production in RASFs to mediate protective effect on bone destruction to mediate anti-arthritis effect. Underlying mechanistic study showed that SIN induced phosphorylation of p62 at Ser349 and Thr269/Ser272 to activate Keap1-Nrf2 signaling in RASFs. In line with the results, we then observed that the anti-arthritic effect of SIN was significantly attenuated in Nrf2 deficient (Nrf2-/-) mice. Notably, we found that p62 expression and phosphorylation at Thr269/Ser272 remarkably reduced, while p62 phosphorylation at Ser351 was up-regulated in Nrf2 deficient mice compared to its wild littermates, indicating that Nrf2 probably negative regulates p62 phosphorylation at Ser351. Collectively, our findings demonstrate that SIN phosphorylated p62 at Ser351 (corresponding to human Ser349) to degrade Keap1 expression and accumulate Nrf2 expression, increased p62 expression and phosphorylation at Thr269/Ser272 to activate p62-Keap1-Nrf2 axis, and finally exerted anti-arthritic effect. The current study not only clarified the anti-arthritic characteristics of SIN but also provided the clue to elucidate the correlation of p62 phosphorylation sites and Nrf2 signaling activation.

Immune Privilege: The Microbiome and Uveitis

Immune privilege (IP), a term introduced to explain the unpredicted acceptance of allogeneic grafts by the eye and the brain, is considered a unique property of these tissues. However, immune responses are modified by the tissue in which they occur, most of which possess IP to some degree. The eye therefore displays a spectrum of IP because it comprises several tissues. IP as originally conceived can only apply to the retina as it contains few tissue-resident bone-marrow derived myeloid cells and is immunologically shielded by a sophisticated barrier – an inner vascular and an outer epithelial barrier at the retinal pigment epithelium. The vascular barrier comprises the vascular endothelium and the glia limitans. Immune cells do not cross the blood-retinal barrier (BRB) despite two-way transport of interstitial fluid, governed by tissue oncotic pressure. The BRB, and the blood-brain barrier (BBB) mature in the neonatal period under signals from the expanding microbiome and by 18 months are fully established. However, the adult eye is susceptible to intraocular inflammation (uveitis; frequency ~200/100,000 population). Uveitis involving the retinal parenchyma (posterior uveitis, PU) breaches IP, while IP is essentially irrelevant in inflammation involving the ocular chambers, uveal tract and ocular coats (anterior/intermediate uveitis/sclerouveitis, AU). Infections cause ~50% cases of AU and PU but infection may also underlie the pathogenesis of immune-mediated “non-infectious” uveitis. Dysbiosis accompanies the commonest form, HLA-B27–associated AU, while latent infections underlie BRB breakdown in PU. This review considers the pathogenesis of uveitis in the context of IP, infection, environment, and the microbiome.

Recovery of Ggt7 and Ace Expressions in the Colon Alleviates Collagen-Induced Arthritis in Rats by Specific Bioactive Polysaccharide Intervention

Rheumatoid arthritis (RA) causes swollen joints and irreversible joint damage and may even elevate cancer risks. Several bioactive nonstarch polysaccharides (NSPs) were reported to alleviate RA, but the key colonic genes accountable for this alleviation were elusive. Using collagen-induced arthritis as an RA model, colonic candidate genes related to RA were selected by transcriptome and methylome. The key genes were determined by comparing the transcriptome, methylome, and quantitative reverse transcription polymerase chain reaction profiles in RA rats with and without Lycium barbarum polysaccharides' treatment and further validated using Angelica sinensis polysaccharides and Astragalus propinquus polysaccharides for comparison. Both colonic genes γ-glutamyltransferase 7 (Ggt7) and angiotensin-I-converting enzyme (Ace) were downregulated by RA, and they were upregulated after L. barbarum polysaccharides' and A. sinensis polysaccharides' intervention that reduced the RA-caused hypermethylation status in nucleotide sites in the exon/promoter region of the two genes. However, the A. propinquus polysaccharides' intervention barely reduced the hypermethylation in the corresponding sites, failing to recover the expressions of these two genes and improve RA. Therefore, the colonic Ggt7 and Ace can be considered as key genes accountable for RA alleviation by bioactive NSP intervention. This study provides a more comprehensive insight into diet intervention to improve RA.

Natural products action on pathogenic cues in autoimmunity: Efficacy in systemic lupus erythematosus and rheumatoid arthritis as compared to classical treatments

Systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), which are characterized by self-perpetuating inflammation and tissue/organ damage, resulting from the failure of lymphocyte auto-tolerance, cause morbidity and mortality worldwide. The current drugs or therapies including conventional non-steroidal anti-inflammatory drugs (NSAIDs) and disease-modifying anti-rheumatic drugs (DMARDs), as well as several biologic therapies such as B cell-targeted, T cell-targeted, cytokines-targeted and cytokines receptors-targeted therapy, cannot completely cure SLE and RA, and are always accompanied by unexpected side effects. Therefore, more studies have explored new methods for therapy and found that the herbal medicine as well as its natural products (NPs) exhibited promising therapeutic value through exerting effects of immunomodulation, anti-inflammation, anti-oxidation, and anti-apoptosis, etc. via regulating abnormal responses in kidney, innate and adaptive immune systems, intestine, synoviocytes, as well as bone system including chondrocytes, osteoclasts, joints and paw tissues. In the present review, we will elucidate the current mainstream drugs and therapies for SLE and RA, and summarize the efficacy and mechanisms of NPs in the treatment of SLE and RA based on available findings including in vitro and in vivo animal models, as well as clinical studies, and further analyze the existing challenges, in order to provide comprehensive evidence for improvement of SLE and RA therapy by NPs and to promote management of these two autoimmune diseases.

Analysis of intestinal immunity and flora in a collagen-induced mouse arthritis model: differences during arthritis progression

Intestinal immunity and flora are reported to be associated with the onset of rheumatoid arthritis. However, differences in the intestinal immunity and flora dynamics between the initial peak and relapse of arthritis have not been investigated. Here we analyzed the lymphocyte populations in different lymphoid tissues, the IgA in feces, and the intestinal flora at the initial peak and the relapse phase of arthritis in a collagen-induced arthritis (CIA) mouse model. In this model compared with the control group, the percentage of RORγt+CD4+ T cells in the mesenteric lymph nodes (mLN) was increased at the initial peak but decreased at the relapse stage of arthritis, and the opposite changes were observed in the spleen. The percentage of Foxp3+CD4+ T cells was unchanged at the initial peak in both tissues but increased only in the mLN at the relapse stage. The IgA in feces increased with the progression of arthritis, and bacterial analysis revealed that some specific bacterial families were changed at the peak and relapse stages of arthritis. Finally, the immune dynamics under different arthritic conditions were examined by integrating these factors using principal component analysis (PCA). PCA showed that the immunological and intestinal flora profiles were different between the initial peak and the relapse of the arthritis. Our findings suggest that the intestinal immunity and the environment change drastically with the progress of arthritis.

Analgesic Mechanism of Sinomenine against Chronic Pain

Purified from the roots of the plant Sinomenium acutum, sinomenine is traditionally used in China and Japan for treating rheumatism and arthritis. Previously, we have demonstrated that sinomenine possessed a broad analgesic spectrum in various chronic pain animal models and repeated administration of sinomenine did not generate tolerance. In this review article, we discussed sinomenine's analgesic mechanism with focus on its role on immune regulation and neuroimmune interaction. Sinomenine has distinct immunoregulative properties, in which glutamate, adenosine triphosphate, nitric oxide, and proinflammatory cytokines are thought to be involved. Sinomenine may alter the unbalanced neuroimmune interaction and inhibit neuroinflammation, oxidative stress, and central sensitization in chronic pain states. In conclusion, sinomenine has promising potential for chronic pain management in different clinical settings.

The Role of Th17/Treg Axis in the Traditional Chinese Medicine Intervention on Immune-Mediated Inflammatory Diseases: A Systematic Review

The Th17/Treg axis plays a crucial role in immune-mediated inflammatory diseases (IMID) and might represent an interesting drug target of treatment strategy for these diseases. Accumulating evidence suggests a role for traditional Chinese medicine (TCM) in the modulation of Th17/Treg axis, but a comprehensive overview which summarizes this field hitherto is lacked. This paper performs a systematic literature review of the regulatory effects of TCM on the imbalance of Th17/Treg axis and its potential mechanisms. In addition, the frequency analysis and network pharmacology for the collected TCM herbs from clinical trial data were performed. The studies reported the changes in the ratio of Th17 and/or Treg cells as well as their transcription factor and related cytokines were included. Frequency analysis of composition of the 39 assessed TCM prescriptions showed that Astragalus membranaceus var.mongholicus (5.20%), Glycyrrhiza uralensis (3.67%), Paeonia obovate (3.06%), Salvia digitaloides (3.06%), and Angelica sinensis (2.75%) were the top five herbal components, which were closely associated to the treatment of IMID. Network pharmacology showed that six target proteins (transforming growth factor (TGF)-beta receptor type-1, TGF-beta receptor type-2, retineic-acid-receptor-related orphan nuclear receptor gamma (ROR-gamma), TGFB2, IL-17 and IL-2, respectively) might be involved in the regulatory effects of TCM on Th17/Treg axis. Moreover, there were nine active ingredients (including Oxymatrine, Baicalin, Triptolide, Paeoniflorin, Sinomenine, Celastrol, Emodin, Diosgenin and Chlorogenic acid) originating from TCM reported to have an immunological regulation effect on the Th17/Treg axis. The highlight of this systematic review is to reveal the pharmacological basis of TCM treating IMID and is helpful for supporting future pharmacologic-driven studies. Further research elucidates the immune-modulating mechanisms on Th17/Treg axis by TCM might provide a broader insight for the treatment of IMID.

Anti-CCL22 increases regulatory T cells in CD4+ T cells of rheumatoid arthritis patients via STAT5 pathway

Abnormality in the number and function of CD4⁺CD25⁺FOXP3⁺ regulatory T cells (Tregs) in peripheral blood has been linked to the initiation and progression of rheumatoid arthritis (RA). Effect of chemokine CCL22 on the number of Tregs in CD4⁺ T cells and the underlying mechanism were investigated. Downregulation of peripheral Tregs were observed while upregulation of serum chemokine CCL22 in RA patients. Tregs count and the expression of FOXP3 (Tregs function-related maker) and phosphorylated-signal transducer and activator of transcription 5 (p-STAT5) in CD4⁺ T cells from RA patients were increased while C-C chemokine receptor 4 (CCR4) was decreased by anti-CCL22 antibody, however, recombinant CCL22 resulted in the opposite effects in CD4⁺ T cells from the healthy control. STAT5 inhibitor significantly reversed the effects of anti-CCL22 antibody. Similarly, sinomenine, an anti-arthritis drug, which decreased CCL22 and CCR4, showed the same trends as the above events, and was reversed by recombinant CCL22 or STAT5 inhibitor. Collectively, anti-CCL22 induced the number of Tregs via STAT5 pathway, leading to expansion of Tregs and subsequently to control of the autoimmune reaction in RA patients. Our study provides s novel strategy for RA treatment.

Modulation of autoimmune arthritis by environmental 'hygiene' and commensal microbiota

Observations in patients with autoimmune diseases and studies in animal models of autoimmunity have revealed that external environmental factors including exposure to microbes and the state of the host gut microbiota can influence susceptibility to autoimmunity and subsequent disease development. Mechanisms underlying these outcomes continue to be elucidated. These include deviation of the cytokine response and imbalance between pathogenic versus regulatory T cell subsets. Furthermore, specific commensal organisms are associated with enhanced severity of arthritis in susceptible individuals, while exposure to certain microbes or helminths can afford protection against this disease. In addition, the role of metabolites (e.g., short-chain fatty acids, tryptophan catabolites), produced either by the microbes themselves or from their action on dietary products, in modulation of arthritis is increasingly being realized. In this context, re-setting of the microbial dysbiosis in RA using prebiotics, probiotics, or fecal microbial transplant is emerging as a promising approach for the prevention and treatment of arthritis. It is hoped that advances in defining the interplay between gut microbiota, dietary products, and bioactive metabolites would help in the development of therapeutic regimen customized for the needs of individual patients in the near future.

The Aryl Hydrocarbon Receptor as an Immune-Modulator of Atmospheric Particulate Matter-Mediated Autoimmunity

This review examines the current literature on the effects of atmospheric particulate matter (PM) on autoimmune disease and proposes a new role for the aryl hydrocarbon receptor (AHR) as a modulator of T cells in PM-mediated autoimmune disease. There is a significant body of literature regarding the strong epidemiologic correlations between PM exposures and worsened autoimmune diseases. Genetic predispositions account for 30% of all autoimmune disease leaving environmental factors as major contributors. Increases in incidence and prevalence of autoimmune disease have occurred concurrently with an increase in air pollution. Currently, atmospheric PM is considered to be the greatest environmental health risk worldwide. Atmospheric PM is a complex heterogeneous mixture composed of diverse adsorbed organic compounds such as polycyclic aromatic hydrocarbons (PAHs) and dioxins, among others. Exposure to atmospheric PM has been shown to aggravate several autoimmune diseases. Despite strong correlations between exposure to atmospheric PM and worsened autoimmune disease, the mechanisms underlying aggravated disease are largely unknown. The AHR is a ligand activated transcription factor that responds to endogenous and exogenous ligands including toxicants present in PM, such as PAHs and dioxins. A few studies have investigated the effects of atmospheric PM on AHR activation and immune function and demonstrated that atmospheric PM can activate the AHR, change cytokine expression, and alter T cell differentiation. Several studies have found that the AHR modulates the balance between regulatory and effector T cell functions and drives T cell differentiation in vitro and in vivo using murine models of autoimmune disease. However, there are very few studies on the role of AHR in PM-mediated autoimmune disease. The AHR plays a critical role in the balance of effector and regulatory T cells and in autoimmune disease. With increased incidence and prevalence of autoimmune disease occurring concurrently with increases in air pollution, potential mechanisms that drive inflammatory and exacerbated disease need to be elucidated. This review focuses on the AHR as a potential mechanistic target for modulating T cell responses associated with PM-mediated autoimmune disease providing the most up-to-date literature on the role of AHR in autoreactive T cell function and autoimmune disease.

Sinomenine Inhibits the Progression of Rheumatoid Arthritis by Regulating the Secretion of Inflammatory Cytokines and Monocyte/Macrophage Subsets

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory arthropathy associated with articular damage and attendant comorbidities. Even although RA treatment has advanced remarkably over the last decade, a significant proportion of patients still do not achieve sustained remission. The cause of RA is not yet known despite the many potential mechanisms proposed. It has been confirmed that RA is associated with dysregulated immune system and persistent inflammation. Therefore, management of inflammation is always the target of therapy. Sinomenine (SIN) is the prescription drug approved by the Chinese government for RA treatment. A previous study found that SIN was a robust anti-inflammation drug. In this study, we screened the different secretory cytokines using inflammation antibody arrays and qRT-PCR in both LPS-induced and SIN-treated RAW264.7 cells followed by evaluation of the ability of SIN to modulate cytokine secretion in a cell model, collagen-induced arthritis (CIA) mouse model, and RA patients. Several clinical indexes affecting the 28-joint disease activity score (DAS28) were determined before and after SIN treatment. Clinical indexes, inflammatory cytokine secretion, and DAS28 were compared among RA patients treated with either SIN or methotrexate (MTX). To explore the mechanism of SIN anti-inflammatory function, RA-associated monocyte/macrophage subsets were determined using flow cytometry in CIA mouse model and RA patients, both treated with SIN. The results demonstrated that SIN regulated IL-6, GM-CSF, IL-12 p40, IL-1α, TNF-α, IL-1β, KC (CXCL1), Eotaxin-2, IL-10, M-CSF, RANTES, and MCP-1 secretion in vivo and in vitro and reduced RA activity and DAS28 in a clinical setting. Furthermore, SIN attenuated CD11b⁺F4/80⁺CD64⁺ resident macrophages in the synovial tissue, CD11b⁺Ly6C⁺CD43⁺ macrophages in the spleen and draining lymph nodes of CIA mice. The percentage of CD14⁺CD16⁺ peripheral blood mononuclear cells was reduced by SIN in RA patients. These data indicated that SIN regulates the secretion of multiple inflammatory cytokines and monocyte/macrophage subsets, thereby suppressing RA progression. Therefore, along with MTX, SIN could be an alternative cost-effective anti-inflammatory agent for treating RA.

Sinomenine alleviates dextran sulfate sodium‑induced colitis via the Nrf2/NQO‑1 signaling pathway

Sinomenine (SIN), a pure alkaloid isolated from Sinomenium acutum, has been widely used in arthritis for its anti‑inflammatory effect, but little is known about the effect of SIN on human ulcerative colitis (UC). In the present study, the effect and mechanism of SIN was examined in a dextran sulfate sodium (DSS)‑induced murine colitis model, which mimics human UC. Oral administration of SIN significantly suppressed the elevated disease activity index and ameliorated colonic histological damage in a DSS‑induced colitis model. Tumor necrosis factor‑α, interleukin‑6 and inducible nitric oxide synthase levels were also reduced as detected by reverse transcription‑quantitative polymerase chain reaction. In addition, SIN reversed the decreased colon length and colonic superoxide dismutase activity. Furthermore, western blot analysis revealed that nuclear factor‑erythroid 2‑related factor 2 (Nrf2) and its downstream genes, heme oxygenase‑1 and NADP(H) quinone oxidoreductase 1 (NQO‑1), were markedly activated by SIN. The current results indicated that SIN alleviated DSS‑induced colitis in mice, which may be due to its antioxidant properties and was at least in part dependent on the Nrf2/NQO‑1 signaling pathway. Therefore, SIN may have potential applications as a protective drug for patients with UC.

Gut-Sourced Vasoactive Intestinal Polypeptide Induced by the Activation of α7 Nicotinic Acetylcholine Receptor Substantially Contributes to the Anti-inflammatory Effect of Sinomenine in Collagen-Induced Arthritis

Sinomenine has long been used for the treatment of rheumatoid arthritis in China. However, its anti-inflammatory mechanism is still debatable because the in vitro minimal effective concentration (≥250 μM) is hardly reached in either synovium or serum after oral administration at a therapeutic dose. Recent findings suggest that the α7 nicotinic acetylcholine receptor (α7nAChR) might mediate the inhibitory effect of sinomenine on macrophage activation, which attracts us to explore the anti-arthritis mechanism of sinomenine by taking neuroendocrine-inflammation axis into consideration. Here, we showed that orally administered sinomenine ameliorated the systemic inflammation of collagen-induced arthritis (CIA) rats, which was significantly diminished by either vagotomy or the antagonists of nicotinic acetylcholine receptors (especially the antagonist of α7nAChR), but not by the antagonists of muscarinic receptor. Sinomenine might bind to α7nAChR through interacting with the residues Tyr184 and Tyr191 in the pocket. In addition, the generation of vasoactive intestinal polypeptide (VIP) from the gut of CIA rats and cultured neuron-like cells was selectively enhanced by sinomenine through the activation of α7nAChR-PI3K/Akt/mTOR pathway. The elevated levels of VIP in the serum and small intestine of rats were negatively correlated with the scores of joint destruction. The crucial role of VIP in the anti-arthritic effect of sinomenine was confirmed by using VIP hybrid, a non-specific antagonist of VIP receptor. Taken together, intestine-sourced VIP mediates the anti-arthritic effect of sinomenine, which is generated by the activation of α7nAChR.

A selective HPLC-MS/MS method for quantification of SND-117 in rat plasma and its application to a pharmacokinetic study

Rheumatoid arthritis (RA), a chronic systemic inflammatory disorder affects many adults. Sinomenine, a natural product, has been clinically available for the treatment of RA in China. SND-117, a sinomenine derivative with much more potent activity, might serve as a candidate for anti-arthritis. The aim of the present study was to develop a sensitive and rapid high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method for quantification of SND-117 in rat plasma and to understand its absolute bioavailability. The HPLC-MS/MS method was developed and fully validated for determination of SND-117 in rat plasma, and the pharmacokinetic differences were investigated after different administration routes. The pharmacokinetics parameters were calculated by non-compartment model with DAS 3.0 software. After the oral or intravenous administration of different doses of SND-117, the time to peak is 1.5h, half-life time is 8-10h. The absolute oral bioavailability of SND-117 in rats was 9.60%. The results showed that SND-117 in rats was quickly absorbed, slowly eliminate, and the kinetics were linear. This method was suitable for pharmacokinetic studies of SNA-117 in rats.

Phytoconstituents as pharmacotherapeutics in rheumatoid arthritis: challenges and scope of nano/submicromedicine in its effective delivery

Objectives

The present review explores the therapeutic application of herbals in rheumatoid arthritis (RA) therapy, and how nano/submicromedicine can be fit in the scope of its therapeutic delivery in RA has been addressed.

Key findings

Incorporation of bioactive such as polyphenols, thymoquinone, resveratrol, hesperidin, curcumin, celastrol and gambogic acid in a dose-dependent manner showed quite high efficacy for the treatment of RA. It can be attributed to their targeting ability against various inflammatory mediators including nitric oxide (NO), cytokines, chemokines, adhesion molecules, NF-kβ, lipoxygenase (LOXs) and arachidonic acid (AA). Despite the presence of significant merits, the use of these bioactives has several demerits such as poor bioavailability as a function of low aqueous solubility and higher first-pass metabolism upon oral administration. The impact of nano/submicromedicine in the delivery of these bioactives against RA has gained wider attention owing to bioavailability enhancement, higher stability and better efficacy.

Conclusion

Phytoconstituents possess immense potential in RA pharmacotherapy, but the obstacles for their effective delivery can be overcome using nano/submicrocarrier-based drug delivery technologies, which maximize the efficacy of these herbal antirheumatic drugs without any systemic adverse effects.

Sinomenine induces the generation of intestinal Treg cells and attenuates arthritis via activation of aryl hydrocarbon receptor

Sinomenine (SIN), an anti-arthritis drug, has previously been proven to exert immunomodulatory activity in rats by inducing intestinal regulatory T-cells (Treg cells). Here, we assessed the effect of SIN on the generation and function of Treg cells in autoimmune arthritis, and the underlying mechanisms in view of aryl hydrocarbon receptor (AhR). The proportions of Treg cells and IL-17-producing T-cells (Th17 cells) differentiated from naive T-cells were analyzed by flow cytometric analysis. The AhR agonistic effect of SIN was tested by analyzing the activation of downstream signaling pathways and target genes. The dependence of intestinal Treg cell induction and arthritis alleviation by SIN on AhR activation was confirmed in a mouse collagen-induced arthritis (CIA) model. SIN promoted the differentiation and function of intestinal Treg cells in vitro. It induced the expression and activity of AhR target gene, promoted AhR/Hsp90 dissociation and AhR nuclear translocation, induced XRE reporter activity, and facilitated AhR/XRE binding in vitro, displaying the potential to be an agonist of AhR. In CIA mice, SIN induced the generation of intestinal Treg cells, and facilitated the immunosuppressive function of these Treg cells as shown by an adoptive transfer test. In addition, the induction of intestinal Treg cells and the anti-arthritic effect of SIN in CIA mice could be largely diminished by the AhR antagonist resveratrol. SIN attenuates arthritis by promoting the generation and function of Treg cells in an AhR-dependent manner.

Sinomenine enhances microglia M2 polarization and attenuates inflammatory injury in intracerebral hemorrhage

Microglia polarization plays a vital role in brain inflammatory injury following intracerebral hemorrhage (ICH). Previous studies have shown that sinomenine possesses potential immunoregulatory capabilities. However, microglia polarization's exact mechanisms in ICH remain uncertain. Therefore, we examined the role of sinomenine on microglia polarization and brain inflammation following ICH. For the experiment, autologous blood models were constructed in C57/BL6 mice. Markers of classically activated (M1) and alternatively activated (M2) microglia were detected by real-time polymerase chain reaction, immunofluorescence, and flow cytometry. Microglial toxicity was assessed using MTT and FACS assays. In addition, the neurological deficit and cerebral water content of ICH mice were also observed. Sinomenine attenuated M1 markers while promoting M2 markers of microglia. Sinomenine also protected hippocampal neurons from indirect toxicity mediated by ICH-treated microglia. Additionally, administration of sinomenine inhibited matrix metalloproteinase (MMP) 3/9 expression, cerebral water content, and neurological deficit. Therefore, sinomenine protected brain function following ICH, perhaps via M2 microglia phenotype induction and MMP 3/9 inhibition. This result suggests that sinomenine is a promising therapeutical strategy in ICH.

Role of the Gut Microbiome in Modulating Arthritis Progression in Mice

Genetics alone cannot explain most cases of rheumatoid arthritis (RA). Thus, investigating environmental factors such as the gut microbiota may provide new insights into the initiation and progression of RA. In this study, we performed 16S rRNA sequencing to characterise the gut microbiota of DBA1 mice that did or did not develop arthritis after induction with collagen. We found that divergence in the distribution of microbiota after induction was pronounced and significant. Mice susceptible to collagen-induced arthritis (CIA) showed enriched operational taxonomic units (OTUs) affiliated with the genus Lactobacillus as the dominant genus prior to arthritis onset. With disease development, the abundance of OTUs affiliated with the families Bacteroidaceae, Lachnospiraceae, and S24-7 increased significantly in CIA-susceptible mice. Notably, germ-free mice conventionalized with the microbiota from CIA-susceptible mice showed a higher frequency of arthritis induction than those conventionalized with the microbiota from CIA-resistant mice. Consistently, the concentration of the cytokine interleukin-17 in serum and the proportions of CD8+T cells and Th17 lymphocytes in the spleen were significantly higher in the former group, whereas the abundances of dendritic cells, B cells, and Treg cells in the spleen were significantly lower. Our results suggest that the gut microbiome influences arthritis susceptibility.

Salidroside ameliorates arthritis-induced brain cognition deficits by regulating Rho/ROCK/NF-κB pathway

The prevalence of cognitive impairment in rheumatoid arthritis (RA) patients was increasingly serious nowadays. The purpose of the current study was to explore whether salidroside (Sal) could alleviate arthritis-induced cognition deficits and examine the relationship between the impairment and Rho/ROCK/NF-κB pathway. Collagen-induced arthritis (CIA) was established by the injection of chicken type II collagen (CII), complete Freund's adjuvant (CFA) and incomplete Freund's adjuvant (IFA). Arthritic lesions of CIA rats were assessed by arthritis index score, swelling of paws and histological analysis. Cognitive deficits symptoms of CIA rats were monitored through Morris water maze test. The contents of pro-inflammatory cytokines tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and interleukin-6 (IL-6) in hippocampus and serum were significantly reduced with salidroside (20 mg/kg, 40 mg/kg) treatment compared with those in the CIA group. In parallel, we demonstrated that the expressions of RhoA, ROCK1, ROCK2, p-NF-κBp65, p-IκBα, p-IKKα and p-IKKβ were enhanced accompanying the investigation arthritis-induced cognition deficits, which were remarkably down-regulated by salidroside and confirmed by the results obtained from western blot and immunohistochemistry. LC-MS/MS results ascertained that Sal could enter into the blood and brain tissues to exhibit the protective effect on arthritis-induced cognitive dysfunction. Therefore, it was assumed that Sal might be a potential therapeutic candidate to treat arthritis-induced brain cognition deficits through the regulation of Rho/ROCK/NF-κB signaling.