Anti-Inflammatory Effect of Geniposide on Regulating the Functions of Rheumatoid Arthritis Synovial Fibroblasts via Inhibiting Sphingosine-1-Phosphate Receptors1/3 Coupling Gαi/Gαs Conversion

The new anti-angiogenesis perspective of rheumatoid arthritis with geniposide: Reducing the extracellular release of HSP70 in HUVECs

BACKGROUND

Angiogenesis is essential for pannus formation and maintenance in rheumatoid arthritis (RA). Heat shock protein 70 kDa (HSP70) can induce angiogenesis by being released extracellularly through exosomes. Geniposide (GE) is the primary pharmacological component of the fruit of Gardenia jasminoides Ellis (GJ). In vivo, we have found that GE is able to reduce HSP70 levels in the synovium and serum of CIA-S and has anti-angiogenic effects. However, the mechanism by which GE inhibits HSP70 to improve angiogenesis is still unclear. This study aims to explore how GE inhibits the extracellular release of HSP70 and its impact on angiogenesis in human umbilical vein endothelial cells (HUVECs).

METHODS

HUVECs' exosomes were extracted using ultracentrifugation and characterized through transmission electron microscope, nanoparticle tracer technology, nano-flow cytometry and Western blotting. The proliferative ability of HUVECs was assessed by EdU and CCK8 assay. Transwell and wound healing assays were used to measure the migration ability of HUVECs, while tube formation assay was employed to evaluate their tube-forming ability. The TNF-α-induced HSP70 release model in HUVECs was established, with extracellular HSP70 levels serving as an evaluation index. Immunofluorescence and co-immunoprecipitation assay were used to analyze the interaction between HSP70 and the lipid raft marker Caveolin-1 (Cav-1). Western blotting was employed to investigate the expression of SphK1/S1P/S1PRs/Gαi pathway-related proteins, and ELISA was utilized to detect extracellular S1P and HSP70 levels.

RESULTS

The exosomes of HUVECs contained HSP70. HUVECs were stimulated by extracellular HSP70, which enhanced their proliferation, migration, and tube-forming abilities. TNF-α (10 ng/mL) significantly increased the release of HSP70, which was inhibited by GE (25 µM-100 µM) in a concentration-dependent manner. GE reduced HSP70 in lipid rafts without affecting Cav-1. GE (100 µM) inhibited proteins in the SphK1/S1P/S1PRs/Gαi pathway, preventing HSP70 release and improving HUVECs' functions compared to the K6PC-5 (SphK1-specific agonist) and TNF-α groups.

CONCLUSION

This study found that GE inhibited the extracellular release of HSP70 by suppressing the SphK1/S1P/S1PRs/Gαi pathway, thereby producing anti-angiogenic effects in vitro. This provides a novel direction and strategy for anti-angiogenesis therapy for RA.

A new look at angiogenesis inhibition of geniposide in experimental arthritis by blocking angiopoietin-2 exocytosis

Angiogenesis is a key player in the pathogenesis of rheumatoid arthritis. Exocytosis from Weibel-Palade bodies is a prerequisite for angiopoietin-2 (Ang-2) to activate endothelial cells and initiate angiogenesis. Geniposide (GE) was previously reported to exert anti-angiogenic effects. The aim of this study was to shed light on whether and how GE regulates Ang-2 exocytosis. A rat model of adjuvant arthritis (AA) was established to evaluate the therapeutic effect of GE (60 and 120 mg/kg) especially in synovial angiogenesis. In addition, the Matrigel plug assay was used to detect the effect of GE (120 and 240 mg/kg) on angiogenesis in AA mice. In vitro, sphingosine-1-phosphate (S1P)-stimulated human umbilical vein endothelial cells (HUVECs) were used to investigate the effect and mechanism of GE on Ang-2 exocytosis. It was found that GE improved the symptoms of AA rats and inhibited angiogenesis in AA, which may be related to the down-regulation of S1P receptors 1, 3 (S1PR1, S1PR3), phospholipase Cβ3 (PLCβ3), inositol 1,4,5-trisphosphate receptor (IP3 R) and Ang-2 expression. The results of in vitro experiments showed that S1P induced rapid release of Ang-2 from HUVECs with multigranular exocytosis. Suppression of the S1P/S1PR1/3/PLCβ3/Ca2+ signal axis by the S1PR1/3 inhibitor VPC23019 and the IP3 R inhibitor 2-APB blocked Ang-2 exocytosis, accompanied by diminished angiogenesis in vitro. GE dose-dependently weakened S1P/S1PR1/3/PLCβ3/Ca2+ signal axis activation, Ang-2 exocytosis and angiogenesis in HUVECs (p < 0.05, p < 0.01). Overall, these findings revealed that angiogenesis inhibition of GE was partly attributed to the intervention of Ang-2 exocytosis through negatively modulating the S1P/S1PR1/3/PLCβ3/Ca2+ signal axis, providing a novel strategy for rheumatoid arthritis anti-angiogenic therapy.

Network Pharmacology and Molecular Docking Explore the Mechanism of Mubiezi-Yinyanghuo Herb Pair in the Treatment of Rheumatoid Arthritis

Objective

Our previous studies have shown that the Mubiezi-Yinyanghuo (MBZ-YYH) herb pair inhibits rheumatoid arthritis (RA) cell proliferation and glycolysis, promising results with an obscure mechanism of action.

Methods

Therefore, it is necessary to explore the main components of MBZ-YYH and unravel the potential mechanism in RA based on network pharmacology and molecular docking methods. Components and targets of MBZ-YYH were retrieved from the TCMSP. Relevant targets of RA were searched in GeneCards, therapeutic target database (TTD), and DisGeNET databases; the common targets of the MBZ-YYH compounds and RA were obtained by comparison; and a component-target interaction network was established by Cytoscape 3.9.1. Gene ontology (GO) analysis and Kyoto Encyclopedia of Gene and Genome (KEGG) pathway enrichment analysis were performed through the David database. Molecular docking was performed by PyMoL2.3.0 and AutoDock Vina1.1.2 software.

Results

7 active ingredients and 58 putatively identified target genes were screened from MBZ, and 16 effective components of YYH and 230 potential targets were identified. There were 29 mutual targets between the two herbs and RA. Through the PPI network, 9 hub targets which contain JUN, CASP3, PPARG, PTGS2, GSK3B, CASP8, HMOX1, ICAM1, and HK2 were screened out. GO term enrichment analysis indicated that positive regulation of the apoptotic process, response to drugs, and response to hypoxia were significantly enriched. Based on KEGG analysis, it was mainly associated with the IL-17 signaling pathway, the TNF signaling pathway, and the p53 signaling pathway. The docking analysis revealed that the effective components showed strong binding activity with the receptors.

Conclusion

The effects of the MBZ-YYH herb pair on RA were coordinated by the interaction of diverse components, which may be through the IL-17 signaling pathway and the TNF signaling pathway, which target GSK3B, HK2, caspase 3, and caspase 8, inhibiting the proliferation and glycolysis of rheumatoid arthritis fibroblast-like synovial cells (RA-FLS) and tending towards an increasing efficacy and decreasing toxicity effect on RA.

Geniposide augments apoptosis in fibroblast-like synoviocytes by restoring hypoxia-enhanced JNK-BNIP3-mediated autophagy

BACKGROUND

As the main effector cells of chronic inflammation and hyperplasia of synovium, fibroblast-like synoviocytes (FLSs) show abnormal proliferation and insufficient apoptosis in the hypoxic microenvironment, which is due to the increase of BNIP3-mediated autophagy. This study aimed to explore the mechanism of geniposide (GE) on hypoxia-induced hyper-proliferative FLSs with a focus on autophagy and the JNK-BNIP3 pathway.

METHODS

The dynamic changes of autophagy, apoptosis, and hypoxia-related proteins in adjuvant arthritis (AA) rats were detected by immunohistochemistry and Western blot. The proliferation, autophagy, apoptosis, and mitochondrial state of FLSs were detected by CCK-8, flow cytometry, immunofluorescence, and transmission electron microscopy, respectively. Western blot, qRT-PCR, and co-immunoprecipitation were used to detect the expression of the JNK-BNIP3 pathway.

RESULTS

The excessive accumulation of BNIP3 in the synovium of AA rats was accompanied by inhibition of apoptosis and an increase in autophagy. GE inhibited the expression of BNIP3, enhanced apoptosis, decreased autophagy, and improved chronic inflammation and hyperplasia of synovium. The amount of autophagy under different oxygen concentrations was the key to mediating the different survival rates of FLSs, and the inhibition of autophagy triggered apoptosis. GE suppressed the proliferation of FLSs and down-regulated autophagy, leading to the accumulation of ROS and the decrease of mitochondrial membrane potential, induced the increase of apoptosis, and suppressed the accumulation of BNIP3 and the hyperphosphorylation of JNK.

CONCLUSION

GE inhibited autophagy by restoring the hypoxia-induced activated JNK-BNIP3 pathway, inducing mitochondrial oxidative damage, augmented apoptosis, and decreased survival rate of FLSs.

Network pharmacology-based prediction and verification of the active ingredients and potential targets of Huagan Decoction for reflux esophagitis

ETHNOPHARMACOLOGICAL RELEVANCE

Huagan Decoction (HGD), a famous traditional Chinese medicine (TCM) formula, has been widely used in the treatment of reflux esophagitis (RE). However, its effective compounds, potential targets and molecular mechanism remain unclear.

AIM OF THE STUDY

To investigate effective compounds, potential targets and molecular mechanism of HGD against RE by using network pharmacology combined with in vitro validation, with the aims of observing the action of HGD and exploring new therapeutic strategies for RE treatment.

MATERIALS AND METHODS

Effective compounds and potential targets of HGD, as well as related genes of RE, were collected from public databases. Pharmacological clustering and Gene Ontology (GO) enrichment analysis were applied to find targets that involving in the anti-inflammatory module. The pathways were drawn using Cytoscape 3.8.0. Important ingredients, potential targets, and signaling pathways were determined through the construction of protein-protein interaction (PPI), GO and Kyoto Encyclopedia of Genes and Genomes (KEGG). Subsequently, cell experiments were carried out.

RESULTS

A total of 54 active ingredients and 240 RE-related gene targets of HGD were identified. The active compound-target network was visualized and pharmacological clustering further sorted 53 proteins that involve in the regulation of inflammatory responses. GO analysis confirmed the classification was statistically significant. Analysis of compound-target network revealed that quercetin and geniposide may be key ingredients for the anti-inflammatory effect of HGD against RE. The potential targets regulated by HGD are IL-6, IL-1β, PTGS2, AKT1, TNF-α, MAPK1, IL-8, IL-10, CCL2 and MAPK3. In vitro experiment showed that quercetin and geniposide could inhibit the inflammatory response of HET-1A cells through p38MAPK/NF-κB signaling pathway, which was consistent with the prediction by the network pharmacology approach.

CONCLUSIONS

Geniposide and quercetin could be effective therapeutic ingredients for the HGD against RE. They play anti-inflammatory effects via down-regulating the pro-inflammatory cytokines and the conduction of p38MAPK/NF-κB signal. This research provides a comprehensive study on the active components, potential targets, and molecular mechanisms of HGD against RE. Moreover, the study supplies a feasible approach to reveal the mechanisms of TCM formula.

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.

Geniposide restricts angiogenesis in experimentary arthritis via inhibiting Dnmt1-mediated PTEN hypermethylation

Neovascularization in rheumatoid arthritis (RA) is a key bridge between malignant proliferative synovial tissue and pannus. In view of previous studies on the efficacy of Geniposide (GE) in experimentary arthritis, the purpose of this study was to investigate the possible mechanism of GE inhibiting angiogenesis by regulating the gene of phosphate and tension homology deleted on chromosome ten (PTEN). In this study, human umbilical vein endothelial cells (HUVEC) and adjuvant arthritis (AA) rat models were performed to research in vitro and in vivo. The results showed that GE treatment significantly reduced synovitis and angiogenesis in AA rats, which may be associated with the increased expression of PTEN with GE treatment. Meanwhile, the hypermethylation of PTEN accompanied by the over-expression of DNA methyltransferases (Dnmts) was demonstrated in TNF-α-induced HUVEC and AA rats. Knockdown of Dnmt1 by Dnmt1- siRNA significantly inhibited the tube formation of HUVEC in vitro. GE significantly restricted the angiogenesis of HUVEC by inhibiting DNA methylation, which was attributed to the down-regulation of Dnmt1 rather than Dnmt3a and Dnmt3b. The anti-angiogenesis effect of GE was further verified in AA model by the inhibition of Dnmt1. These results indicate that GE exhibited anti-angiogenesis effects in experimentary arthritis by inhibiting Dnmt1-mediated PTEN gene hypermethylation, which may brings new insights for the prevention and research of RA.

Metabonomic analysis of abnormal sphingolipid metabolism in rheumatoid arthritis synovial fibroblasts in hypoxia microenvironment and intervention of geniposide

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by a joint hypoxia microenvironment. Our previous untargeted metabolomics study found that sphingolipid (SPL) metabolism was abnormal in the joint synovial fluid samples from adjuvant arthritis (AA) rats. Geniposide (GE), an iridoid glycoside component of the dried fruit of Gardenia jasminoides Ellis, is commonly used for RA treatment in many Asian countries. At present, the mechanism of GE in the treatment of RA, especially in the joint hypoxia microenvironment, is not entirely clear from the perspective of SPL metabolism. The purpose of this research was to explore the potential mechanism of abnormal SPL metabolism in RA joint hypoxia microenvironment and the intervention effect of GE, through the untargeted metabolic analysis based on the ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS). Arthritis index, foot swelling and histopathology were used to assess whether the AA rat model was successfully established. The SPLs extracts collected from AA rats’ synovial tissue, serum and rheumatoid arthritis synovial fibroblasts (RASFs, MH7A cells, hypoxia/normoxia culture) were analyzed by metabolomics and lipdomics approach based on UPLC-Q-TOF/MS, to identify potential biomarkers associated with disorders of GE regulated RA sphingolipid metabolism. As a result, 11 sphingolipid metabolites related to RA were screened and identified. Except for galactosylceramide (d18:1/20:0), GE could recover the change levels of the above 10 sphingolipid biomarkers in varying degrees. Western blotting results showed that the changes in ceramide (Cer) level regulated by GE were related to the down-regulation of acid-sphingomyelinase (A-SMase) expression in synovial tissue of AA rats. To sum up, this research examined the mechanism of GE in the treatment of RA from the perspective of SPL metabolism and provided a new strategy for the screening of biomarkers for clinical diagnosis of RA.

Geniposide alleviates VEGF-induced angiogenesis by inhibiting VEGFR2/PKC/ERK1/2-mediated SphK1 translocation

BACKGROUND

Rheumatoid arthritis (RA) is an angiogenesis-dependent disease caused by the imbalance of pro- and anti-angiogenic factors. More effective strategies to block synovial angiogenesis in RA should be studied. Geniposide (GE), a natural product isolated from the fruit of Gardenia jasminoides Ellis (GJ), is reported to have anti-inflammatory, anti-angiogenic and other pharmacological effects. However, the underlying mechanism through which GE affects synovial angiogenesis in RA remains unclear.

PURPOSE

In this research, we aimed to elucidate the effect and potential mechanisms of GE on angiogenesis in RA.

MATERIALS AND METHODS

Synovial angiogenesis in patients with RA and a rat model of adjuvant arthritis (AA) was detected by hematoxylin and eosin (HE) staining, immunohistochemistry (IHC), and western blottiing. The biological functions of vascular endothelial cells (VECs) and sphingosine kinase 1 (SphK1) translocation were checked by CCK-8, EdU, Transwell, tube formation, co-immunoprecipitation assays, and laser scanning confocal microscopy. The effect of the SphK1 gene on angiogenesis was assessed by transfection of SphK1-siRNA in cells and mices. The effect of GE on VEGF-induced angiogenesis was measured by Matrigel plug assay in a mouse model of AA.

RESULTS

GE effectively inhibited synovial angiogenesis and alleviated the disease process. SphK1, as a new regulatory molecule, has a potentially important relationship in regulating VEGF/VEGFR2 and S1P/S1PR1 signals. SphK1 translocation was activated via the VEGFR2/PKC/ERK1/2 pathway and was closely linked to the biological function of VECs. GE significantly reduced SphK1 translocation, thereby ameliorating the abnormal biological function of VECs. Furthermore, after transfection of SphK1 siRNA in VECs and C57BL/6 mice, silencing SphK1 caused effectively attenuation of VEGF-induced VEC biological functions and angiogenesis. In vivo, the Matrigel plug experiment indicated that GE significantly inhibited pericyte coverage, basement membrane formation, vascular permeability, and fibrinogen deposition.

CONCLUSIONS

Our findings suggest that GE inhibited VEGF-induced VEC biological functions and angiogenesis by reducing SphK1 translocation. Generally, studies have revealed that GE down-regulated VEGFR2/PKC/ERK1/2-mediated SphK1 translocation and inhibited S1P/S1PR1 signaling activation, thereby alleviating VEGF-stimulated angiogenesis. The above evidences indicated that angiogenesis inhibition may provide a new direction for RA treatment.

Molecular Mechanism of Sphingosine-1-Phosphate Receptor 1 Regulating CD4+ Tissue Memory in situ T Cells in Primary Sjogren's Syndrome

Objective

Although extensive research has been carried out on CD4⁺T cells infiltrating the labial glands in patients with primary Sjögren’s Syndrome (pSS), it is still unclear how CD4⁺T cells remain in the labial gland tissue and develop into tissue resident cells. The aim of this study was to investigate the molecular mechanism by which CD4⁺T reside in labial glandular tissue of pSS patients.

Methods

Lymphocyte infiltration in labial salivary glands (LSG) of pSS patients was detected by H&E staining. Expression of sphingosine-1-phosphate receptor 1 (S1PR1) in LSG was examined by Immunohistochemistry. Immunofluorescence analyses were utilized to detect the co-expression of CD4, CD69 and S1PR1 in T cells of LSG of pSS patients. Expression of gene S1pr1 in peripheral blood CD4⁺T cells of healthy controls and pSS patients was detected by quantitative real-time PCR (QPCR). QPCR was used to examine the expression of gene S1pr1, Klf2, and Cd69 in the CD4⁺T cells that were co-cultured in vitro with cytokines TNF-α, TGF-β, and IL-33.

Results

S1PR1 was expressed in the infiltrating monocytes in LSG of pSS patients, and S1PR1 was weakly or even not expressed in cytoplasm of CD4⁺CD69⁺T_RM cells of LSG in patients with pSS. Expression of gene S1pr1 in peripheral blood CD4⁺T cells of pSS patients was about three-fifths of that of healthy controls (P < 0.05). Expression of genes S1pr1 (P < 0.001) and Klf-2 (P < 0.001) was significantly decreased, and the expression of gene Cd69 (P < 0.05) was significantly increased in peripheral blood CD4⁺T cells of pSS patients co-cultured in vitro with cytokines TNF-α, TGF-β, and IL-33.

Conclusion

Our study suggests that the decrease of S1pr1 gene expression may provide a molecular basis for promoting the tissue retention and development of CD4⁺CD69⁺T_RM cells.

The interplay between fibroblast-like synovial and vascular endothelial cells leads to angiogenesis via the sphingosine-1-phosphate-induced RhoA-F-Actin and Ras-Erk1/2 pathways and the intervention of geniposide

The changes of fibroblast-like synoviocytes (FLSs) and vascular endothelial cells (VECs) biological functions are closely related to angiogenesis in rheumatoid arthritis (RA). Nevertheless, how the crosstalk between FLSs and VECs interferes with RA is far from being clarified. Herein, we studied the effect of the reciprocal interactions between FLSs and VECs on angiogenesis and mechanism of geniposide (GE). After administration of GE, improvement of synovial hyperplasia in adjuvant arthritis rats was accompanied by downregulation of SphK1 and p-Erk1/2. The dynamic interaction between FLSs and VECs triggers the release of S1P by activating p-Erk1/2 and SphK1, then activating RhoA-F-actin and Ras-Erk1/2 pathways. When exposed to the inflammatory microenvironment mediated by FLSs-VECs crosstalk, proliferation, migration, and permeability of VECs were enhanced, the angiogenic factors were imbalanced. Meanwhile, the proliferation and secretory ability of FLSs increased. Interestingly, depletion of S1P or blocking of the activation of SphK1 by GE and PF-543 prevented the changes. In conclusion, S1P released during FLSs-VECs crosstalk changed their biological functions by activating RhoA-F-actin and Ras-Erk1/2 pathways. GE acted on p-Erk1/2 and SphK1, inhibited the secretion of S1P, and blocked the interplay between FLSs and VECs. These results provide new insights into the mechanism of angiogenesis in RA.