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-1ß, 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.

Sinomenine ameliorates collagen-induced arthritis in mice by targeting GBP5 and regulating the P2X7 receptor to suppress NLRP3-related signaling pathways.

Sinomenine (SIN) is an isoquinoline alkaloid isolated from Sinomenii Caulis, a traditional Chinese medicine used to treat rheumatoid arthritis (RA). Clinical trials have shown that SIN has comparable efficacy to methotrexate in treating patients with RA but with fewer adverse effects. In this study, we explored the anti-inflammatory effects and therapeutic targets of SIN in LPS-induced RAW264.7 cells and in collagen-induced arthritis (CIA) mice. LPS-induced RAW264.7 cells were pretreated with SIN (160, 320, 640 µM); and CIA mice were administered SIN (25, 50 and 100 mg·kg-1·d-1, i.p.) for 30 days. We first conducted a solvent-induced protein precipitation (SIP) assay in LPS-stimulated RAW264.7 cells and found positive evidence for the direct binding of SIN to guanylate-binding protein 5 (GBP5), which was supported by molecular simulation docking, proteomics, and binding affinity assays (KD = 3.486 µM). More importantly, SIN treatment markedly decreased the expression levels of proteins involved in the GBP5/P2X7R-NLRP3 pathways in both LPS-induced RAW264.7 cells and the paw tissue of CIA mice. Moreover, the levels of IL-1ß, IL-18, IL-6, and TNF-α in both the supernatant of inflammatory cells and the serum of CIA mice were significantly reduced. This study illustrates a novel anti-inflammatory mechanism of SIN; SIN suppresses the activity of NLRP3-related pathways by competitively binding GBP5 and downregulating P2X7R protein expression, which ultimately contributes to the reduction of IL-1ß and IL-18 production. The binding specificity of SIN to GBP5 and its inhibitory effect on GBP5 activity suggest that SIN has great potential as a specific GBP5 antagonist.

Iristectorigenin C suppresses LPS-induced macrophages activation by regulating mPGES-1 expression and p38/JNK pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Nonsteroidal anti-inflammatory drugs (NSAIDs) have been used clinically to treat inflammatory diseases clinically. However, the adverse effects of NSAIDs cannot be ignored. Therefore, it is critical for us to find alternative anti-inflammatory drugs that can reduce adverse reactions to herbal medicine, such as Iris tectorum Maxim., which has therapeutic effects and can treat inflammatory diseases and liver-related diseases. AIM OF THE STUDY: This study aimed to isolate active compounds from I. tectorum and investigate their anti-inflammatory effects and action mechanisms. MATERIALS AND METHODS: Fourteen compounds were isolated from I. tectorum using silica gel column chromatography, Sephadex LH-20, ODS and high performance liquid chromatography, and their structures were identified by examining physicochemical properties, ultraviolet spectroscopy, infrared spectroscopy, mass spectrometry, and nuclear magnetic resonance spectroscopy. Classical inflammatory cell models were established using lipopolysaccharide (LPS)-stimulated RAW264.7 cells and rat primary peritoneal macrophages to examine the effect of these compounds. To examine the action mechanisms, the nitric oxide (NO) levels were measured by Griess reagent and the levels of inflammatory cytokines in the supernatant were measured by ELISA; The expressions of major proteins in prostaglandin E2 (PGE2) synthesis and the nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways were examined by Western blotting, and the mRNA expression levels were measured by quantitative real-time polymerase chain reaction; and the nuclear translocation of p65 was examined by high content imaging. Molecular docking was used to predict the binding of active compound to target protein. RESULTS: Our findings revealed that Iristectorigenin C (IT24) significantly inhibited the levels of NO and PGE2 without affecting cyclooxygenase (COX)-1/COX-2 expression in LPS-induced RAW264.7 cells and rat peritoneal macrophages. Furthermore, IT24 was shown to decrease the expression of microsomal prostaglandin synthetase-1 (mPGES-1) in LPS-induced rat peritoneal macrophages. IT24 did not suppress the phosphorylation and nuclear translocation of proteins in the NF-κB pathway, but it inhibited the phosphorylation of p38/JNK in LPS-stimulated RAW264.7 cells. Additionally, molecular docking analysis indicated that IT24 may directly bind to the mPGES-1 protein. CONCLUSION: IT24 might inhibit mPGES-1 and the p38/JNK pathway to exert its anti-inflammatory effects and could be also developed as an inhibitor of mPGES-1 to prevent and treat mPGES-1-related diseases, such as inflammatory diseases, and holds promise for further research and drug development.

(9S,13R)-12-oxo-phytodienoic acid attenuates inflammation by inhibiting mPGES-1 and modulating macrophage polarization via NF-κB and Nrf2/HO-1 pathways.

Non-steroidal anti-inflammatory drugs (NSAIDs) relieve inflammation by suppressing prostaglandin E2/cyclooxygenase 2 (PGE2/COX-2) with cardiovascular and gastrointestinal bleeding risk. Theoretically, suppressing PGE2 through inhibiting the terminal synthase microsomal prostaglandin E2 synthase-1 (mPGES-1) instead of upstream COX-2 is ideal for inflammation. Here, (9S,13R)-12-oxo-phytodienoic acid (AA-24) extracted from Artemisia anomala was first screened as an anti-inflammatory candidate and decreased inducible nitric oxide synthase (iNOS), nitric oxide (NO), mPGES-1, and PGE2 without affecting COX-1/2, thromboxane A2 (TXA2) and prostaglandin I2 (PGI2). Besides, AA-24 suppressed the differentiation of M0 macrophages to M1 phenotype but enhanced it to M2 phenotype, blocked the activation of NF-κB pathway, and increased the activation of Nrf2 and heme oxygenase-1 (HO-1). Moreover, AA-24 selectively inhibited mPGES-1 and reduced inflamed paw edema in carrageenan-induced mice. In conclusion, AA-24 attenuates inflammation by inhibiting mPGES-1 and modulating macrophage polarization via the NF-κB and Nrf2/HO-1 pathways and could be a promising candidate for developing anti-inflammatory drugs.

Sinomenine increases the methylation level at specific GCG site in mPGES-1 promoter to facilitate its specific inhibitory effect on mPGES-1.

Prostaglandin E2 (PGE2) in cancer and inflammatory diseases is a key mediator of disease progression. Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used to inhibit the expression of PGE2 by depressing cyclooxygenase (COX) in inflammatory treatments. However, the inhibition to COXs may cause serious side effects. Thus, it is urgent to develop new anti-inflammatory drugs aiming new targets to inhibit PGE2 production. Microsomal prostaglandin E synthase 1 (mPGES-1) catalyzes the final step of PGE2 biosynthesis. Therefore, the selective inhibition of mPGES-1 has become a promising strategy in the treatments of cancer and inflammatory diseases. Our previous studies confirmed that sinomenine (SIN) is a specific mPGES-1 inhibitor. However, the exact mechanism by which SIN inhibits mPGES-1 remains unknown. This study aimed to explain the regulation effect of SIN to mPGES-1 gene expression by its DNA methylation induction effect. We found that the demethylating agent 5-azacytidine (5-AzaC) reversed the inhibitory effect of SIN to mPGES-1. Besides, SIN selectively increased the methylation level of the promoter region in the mPGES-1 gene while the pretreatment of 5-AzaC suppressed this effect. The results also shows that pretreatment with SIN increased the methylation level of specific GCG sites in the promoter region of mPGES-1. This specific methylation site may become a new biomarker for predicting and diagnosing RA and cancer with high expression of mPGES-1. Also, our research provides new ideas and solutions for clinical diagnosis and treatment of diseases related to mPGES-1 and for targeted methylation strategy in drug development.

Establishment of a High Content Image Platform to Measure NF-κB Nuclear Translocation in LPS-induced RAW264.7 Macrophages for Screening Anti-inflammatory Drug Candidates.

BACKGROUND: High Content Image (HCI), an automatic imaging and analysis system, provides a fast drug screening method by detecting the subcellular distribution of protein in intact cells. OBJECTIVE: This study established the first standardized HCI platform for lipopolysaccharide (LPS)-induced RAW264.7 macrophages to screen anti-inflammatory compounds by measuring nuclear factor-κB (NF-κB) nuclear translocation. METHODS: The influence of the cell passages, cell density, LPS induction time and concentration, antibody dilution, serum, dimethyl sulfoxide, and analysis parameters on NF-κB nuclear translocation and HCI data quality was optimized. The BAY-11-7085, the positive control for inhibiting NF-κB, and the Western blot assay were separately employed to verify the stability and reliability of the platform. Lastly, the effect of BHA on NO release, iNOS expression, IL-1ß, IL-6, and TNF-α mRNA in LPS-induced RAW264.7 cells was detected. RESULTS: The optimal conditions for measuring NF-κB translocation in LPS-induced RAW264.7 cells by HCI were established. Cells that do not exceed 22 passages were seeded at a density of 10 k cells/well and pretreated with compounds following 200 ng/mL LPS for 40 min. Parameters including the nuclear area of 65 µm2, cell area of 80 µm2, collar of 0.9 µm, and sensitivity of 25% were recommended for image segmentation algorithms in the analysis workstation. Benzoylhypaconine from aconite was screened for the first time as an anti-inflammatory candidate by the established HCI platform. The inhibitory effect of benzoylhypaconine on NF-κB translocation was verified by Western blot. Furthermore, benzoylhypaconine reduced the release of NO, inhibited the expression of iNOS, and decreased the mRNA levels of IL-1ß, IL-6, and TNF-α. CONCLUSION: The established HCI platform could be applied to screen anti-inflammatory compounds by measuring the NF-κB nuclear translocation in LPS-induced RAW264.7 cells.

Microsomal prostaglandin E2 synthase-1 and its inhibitors: Molecular mechanisms and therapeutic significance.

Inflammation is closely linked to the abnormal phospholipid metabolism chain of cyclooxygenase-2/microsomal prostaglandin E2 synthase-1/prostaglandin E2 (COX-2/mPGES-1/PGE2). In clinical practice, non-steroidal anti-inflammatory drugs (NSAIDs) as upstream COX-2 enzyme activity inhibitors are widely used to block COX-2 cascade to relieve inflammatory response. However, NSAIDs could also cause cardiovascular and gastrointestinal side effects due to its inhibition on other prostaglandins generation. To avoid this, targeting downstream mPGES-1 instead of upstream COX is preferable to selectively block overexpressed PGE2 in inflammatory diseases. Some mPGES-1 inhibitor candidates including synthetic compounds, natural products and existing anti-inflammatory drugs have been proved to be effective in in vitro experiments. After 20 years of in-depth research on mPGES-1 and its inhibitors, ISC 27864 have completed phase II clinical trial. In this review, we intend to summarize mPGES-1 inhibitors focused on their inhibitory specificity with perspectives for future drug development.

Macrophage 3D migration: A potential therapeutic target for inflammation and deleterious progression in diseases.

Macrophages are heterogeneous cells that have different physiological functions, such as chemotaxis, phagocytosis, endocytosis, and secretion of various factors. All physiological functions of macrophages are integral to homeostasis, immune defense and tissue repair. However, in several diseases, macrophages are recruited from the blood towards inflammatory sites. This process is called macrophage migration, which promotes deleterious disease progression. Macrophage migration is a key player in many inflammatory diseases, autoimmune diseases and cancers because it contributes to the accumulation of proinflammatory factors, the destruction of tissues and the development of tumors. Therefore, macrophage migration is proposed to be a potential therapeutic target. Macrophages migrate between two-dimensional (2D) and three-dimensional (3D) environments, implying that distinct migratory features and mechanisms are involved. Compared with the 2D migration of macrophages, 3D migration involves more complex variations in cellular morphology and dynamics. The structure of the extracellular matrix, a key factor, is modified in diseases that influence macrophage 3D migration. Macrophage 3D migration relates to disease pathology. Research that focuses on macrophage 3D migration is an emerging field and was reviewed in this article to indicate the molecular and cellular mechanisms of macrophage migration in 3D environments and to provide potential targets for controlling disease progression associated with this migration.

Nardosinanone N suppresses LPS-induced macrophage activation by modulating the Nrf2 pathway and mPGES-1.

The side effects of nonsteroidal anti-inflammatory drugs (NSAIDs) in the cardiovascular system mainly result from its inhibitory effect on cyclooxygenase-2 (COX-2). Since NSAIDs are one of the most commonly used anti-inflammatory drugs in the clinic, it is necessary to identify new anti-inflammatory drugs that are safer than NSAIDs. Nardosinanone N (NAN), a compound isolated from the roots and rhizomes of Nardostachys chinensis, was evaluated for its anti-inflammatory effects using the lipopolysaccharide (LPS)-stimulated RAW264.7 cell line and rat peritoneal macrophage models. First, we found that NAN down regulated the levels of nitric oxide (NO), inducible nitric oxide synthase (iNOS) and prostaglandin E2 (PGE2), but not cyclooxygenase-2 (COX-2). Additionally, NAN reduced the M1 macrophage phenotype and increased the M2 macrophage phenotype. Furthermore, mechanistic studies showed that NAN activated the nuclear factor-erythroid 2 -related factor 2 (Nrf2) signaling pathway, which, in turn, increased the expression of antioxidant protein heme oxygenase-1 (HO-1) to achieve its anti-inflammatory effect. Finally, Nrf2 siRNA and the HO-1 inhibitor significantly attenuated the anti-inflammatory effect of NAN. More interestingly, we found that NAN did not affect COX-2 expression and activity but reduced the PGE2 concentration by selective inhibition of microsomal prostaglandin E synthase-1 (mPGES-1). In conclusion, NAN may be a new anti-inflammatory drug that has fewer side effects than NSAIDs and can be a new potential Nrf2 activator and mPGES-1 inhibitor.

3, 4-seco-Labdane diterpenoids from the leaves of Callicarpa nudiflora with anti-inflammatory effects.

Four new 3, 4-seco-labdane diterpenoids, nudiflopenes J-M, were isolated from the leaves of Callicarpa nudiflora along with six known compounds. The structures of these diterpenoids were determined by comprehensive spectroscopic analysis. All the isolated compounds were evaluated for their inhibitory effects on NO production in LPS-stimulated RPMs and RAW264.7 cells. The results suggest that nudiflopenes J-M and other four known compounds showed significant inhibitory effects against NO production comparable to the positive control dexamethasone.

Nardochinoid B Inhibited the Activation of RAW264.7 Macrophages Stimulated by Lipopolysaccharide through Activating the Nrf2/HO-1 Pathway.

Nardochinoid B (NAB) is a new compound isolated from Nardostachys chinensis. Although our previous study reported that the NAB suppressed the production of nitric oxide (NO) in lipopolysaccharide (LPS)-activated RAW264.7 cells, the specific mechanisms of anti-inflammatory action of NAB remains unknown. Thus, we examined the effects of NAB against LPS-induced inflammation. In this study, we found that NAB suppressed the LPS-induced inflammatory responses by restraining the expression of inducible nitric oxide synthase (iNOS) proteins and mRNA instead of cyclooxygenase-2 (COX-2) protein and mRNA in RAW264.7 cells, implying that NAB may have lower side effects compared with nonsteroidal anti-inflammatory drugs (NSAIDs). Besides, NAB upregulated the protein and mRNA expressions of heme oxygenase (HO)-1 when it exerted its anti-inflammatory effects. Also, NAB restrained the production of NO by increasing HO-1 expression in LPS-stimulated RAW264.7 cells. Thus, it is considered that the anti-inflammatory effect of NAB is associated with an induction of antioxidant protein HO-1, and thus NAB may be a potential HO-1 inducer for treating inflammatory diseases. Moreover, our study found that the inhibitory effect of NAB on NO is similar to that of the positive drug dexamethasone, suggesting that NAB has great potential for developing new drugs in treating inflammatory diseases.

Activation of Nrf2/HO-1 Pathway by Nardochinoid C Inhibits Inflammation and Oxidative Stress in Lipopolysaccharide-Stimulated Macrophages.

The roots and rhizomes of Nardostachys chinensis have neuroprotection and cardiovascular protection effects. However, the specific mechanism of N. chinensis is not yet clear. Nardochinoid C (DC) is a new compound with new skeleton isolated from N. chinensis and this study for the first time explored the anti-inflammatory and anti-oxidant effect of DC. The results showed that DC significantly reduced the release of nitric oxide (NO) and prostaglandin E2 (PGE2) in lipopolysaccharide (LPS)-activated RAW264.7 cells. The expression of pro-inflammatory proteins including inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were also obviously inhibited by DC in LPS-activated RAW264.7 cells. Besides, the production of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were also remarkably inhibited by DC in LPS-activated RAW264.7 cells. DC also suppressed inflammation indicators including COX-2, PGE2, TNF-α, and IL-6 in LPS-stimulated THP-1 macrophages. Furthermore, DC inhibited the macrophage M1 phenotype and the production of reactive oxygen species (ROS) in LPS-activated RAW264.7 cells. Mechanism studies showed that DC mainly activated nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway, increased the level of anti-oxidant protein heme oxygenase-1 (HO-1) and thus produced the anti-inflammatory and anti-oxidant effects, which were abolished by Nrf2 siRNA and HO-1 inhibitor. These findings suggested that DC could be a new Nrf2 activator for the treatment and prevention of diseases related to inflammation and oxidative stress.

Nardochinoids A-C, Three Dimeric Sesquiterpenoids with Specific Fused-Ring Skeletons from Nardostachys chinensis.

Three unusual sesquiterpenoid dimers, nardochinoids A-C (1-3), were isolated from Nardostachys chinensis Batal. Compound 1 features a rare fused 3,8-dioxatricyclo[7.2.1.01,6]dodecane-11-one ring system, compound 2 is the first nitrogen-containing nornardosinane-aristolane sesquiterpene conjugate, and compound 3 represents the first example of the dimer of a nornardosinane and a nardosinane sesquiterpene. Their structures were characterized by NMR spectroscopic methods and X-ray single-crystal diffraction analysis. Compound 3 showed significant anti-inflammatory activities.