ABSTRACT
This study started from the effect of baicalin (BC), the main active component of the labiaceae plant Scutellaria baicalensis, on collagen-induced arthritis (CIA) in rats, to explore the mechanism of glucose metabolism reprogramming in fibroblast like synoviocytes (FLSs), a key effector cell of synovial inflammation in rheumatoid arthritis (RA). First of all, CIA rats and tumor necrosis factor-α (TNF-α)-induced RASFs in vitro and in vivo models were established, the arthritis index (AI) score and histopathological changes of CIA rats after BC administration were observed, and the levels of inflammatory factors in serum and cell supernatant were quantified by ELISA, immunocytochemistry and Western blot were used to detect the expression of G-protein-coupled receptor 81 (GPR81) and pyruvate dehydrogenase kinase 1 (PDK1) proteins. In addition, the kit was used to measure the levels of key products and enzyme activities in glucose metabolism reprogramming. The results showed that BC (50, 100 and 200 mg·kg-1) could alleviate the symptoms of arthritis in CIA rats in a dose-dependent manner, inhibit synovial hyperplasia, alleviate the infiltration of inflammatory cells, down-regulate the levels of pro-inflammatory factors TNF-α and interleukin (IL)-1β, and up-regulate the levels of anti-inflammatory factor IL-10 in CIA rats. At the same time, the secretion levels of lactate, pyruvate, acetyl-CoA, citrate and the activity of lactate dehydrogenase B (LDH-B) were decreased, and the expressions of GRP81 and PDK1 were down-regulated, suggesting that BC mediated the reprogramming process of glucose metabolism. However, when GPR81 inhibitor 3-OBA inhibited lactate uptake, the activity of LDH-B was significantly increased, suggesting that BC inhibited the expression of PDK1, a key enzyme in the reprogramming metabolism from glycolysis to oxidative phosphorylation. All animal experiments in this study were conducted in accordance with the ethical standards of the Laboratory Animal Care Center of Anhui University of Chinese Medicine (approval number: AHUCM-rats-2021049). These studies revealed that baicalin mediated metabolic reprogramming of RASFs from glycolysis to oxidative phosphorylation by inhibiting PDK1 protein expression, and alleviated joint inflammation in CIA rats.
ABSTRACT
Objective:To observe the effect of Fengshi Qutong capsule (FSQTC) on protein kinase B(Akt) and mitogen-activated protein kinase (MAPK) signaling pathways of rheumatoid arthritis (RA). Method:Collagen-induced arthritis (CIA) was induced in SD rats, and the synovial membranes of the knee joints were prepared after 19 days of oral administration of 0.25, 0.5, 1 g·kg-1 FSQTC. MH7A cells were induced by tumor necrosis factor-α (TNF-α, 20 μg·L-1) in vitro, and human umbilical vein endothelial cells (HUVEC) were induced by vascular endothelial growth factor (VEGF). FSQTC (0.02, 0.1, 0.5 μg·L-1) were added to MH7A/HUVEC cells, and then the cells were collected. Proteins of synovial tissue, MH7A and HUVEC cells were extracted, and then were detected the expresstion of p-Akt, p-p38 MAPK, p-extracellular signal-regulated kinase(ERK) and p-Jun n-terminal kinase(JNK) by Western blot. Result:The expression levels of p-Akt, p-p38 MAPK, p-ERK and p-JNK in the synovial membrane of CIA model were significantly increased compared with normal group (P-1·d-1 FSQTC significantly decreased their expression levels (PPα or VEGF were increased (P-1 FSQTC (PPConclusion:FSQTC can down-regulate the abnormal activation of Akt and MAPK signaling pathways in the synovial membrane of CIA rats, fibroblast synovial cells and vascular endothelial cells, which is related to the inhibition of synovial angiogenesis in the treatment of RA.
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Objective:It has been found that serum CXCL16 concentration in rheumatoid arthritis (RA) patients are significantly higher than those in osteoarthritis (OA) and normal subjects, and are positively correlated with disease activity and bone erosion.However, how is CXCL16 involved in the pathogenesis of RA is unclear.To evaluate the expression of CXCL16 and its receptor CXCR6 in fibroblast-like synoviocytes (FLS) of rheumatoid arthritis (RA) patients, and to explore the role of CXCL16 in the proliferation of RA-FLS.Methods: FLS were isolated from knee synovial tissues obtained from 8 patients of RA, 7 osteoarthritis (OA) and 3 normal controls.The diagnosis of RA was in line with the 1987 American Rheumatology Association (ACR) RA classification criteria, osteoarthritis met the 1996 ACR revised knee osteoarthritis classification criteria.Control synovium were obtained from trauma caused knee joint injury in healthy individuals who required surgery.Human knee FLS were cultured by tissue explants adherent method.FLS between passages 3 and 5 were used in the experiment.Expression of CXCL16 and its receptor CXCR6 were performed in Western blot analysis.FLS proliferation follo-wing stimulation with TNF-α and different concentrations of CXCL16 was examined by cell counting kit-8 (CCK-8).Expression of phosphorylated AKT (pAKT) in RA-FLS stimulated by CXCL16 was quantified by Western blot.Different concentrations of recombinant human CXCL16 were added to the culture medium of RA-FLS.After 48 h culture, supernantants were collected, and TNF-α, IL-6, RANKL and MMP3 in culture supernatants of RA-FLS were determined by enzyme-linked immunosorbent assays (ELISA) operated following the kit instructions.Results: Expression of CXCL16 and CXCR6 in RA-FLS was significantly higher than that of OA and controls (P<0.05), but no significant difference was found between OA-FLS and control FLS.Proliferation of RA-FLS was markedly up-regulated after stimulation of CXCL16 (P <0.05).In the case of the CXCL16 stimulated OA-FLS and control FLS, the FLS proliferation remained basically unchanged.Expression of phosphorylated AKT in RA-FLS increased remarkably in condition of CXCL16 (50,100, 200 μg/L) stimulation.The levels of IL-6 and RANKL in culture supernatants of RA-FLS were obviously increased under CXCL16 (200 μg/L) stimulation, while TNF-α and MMP-3 levels in the culture supernatants remained unchanged after CXCL16 (200 μg/L) stimulation.Conclusion: This study shows that the expression of CXCL16 and its receptor was highly elevated in RA-FLS.Recombinant CXCL16 promoted RA-FLS proliferation and activation in vitro.All these indicate that CXCL16 play an important role in the pathogenesis of RA, anti-CXCL16 treatment may help to relieve inflammation and bone damage of RA patients.However, due to the limitations of this study, the role of CXCL16 and its receptors in RA-FLS remains to be elucidated by further research.
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This study was aimed to observe the influence of Discornin Tablets on activation nuclear transcription factor NF-κBp65 of rheumatoid arthritis (RA) cell model as well as the expression of MMP-9, VEGF and tumor necrosis factor-α (TNF-α). Interleukin-17 (IL-17) and TNF-α were used for stimulating RSC-364 cells. Discornin Tablets at different concentrations were used for intervention. The influence of Discornin Tablets in different concentrations on cell viability was detected by MTT method. Expressions of NF-κBp65 and its inhibitory protein (IκB-α) in each group were detected by western blot method. Changes in VEGF, MMP-9 and TNF-α protein levels in cell broth supernatant were checked by ELISA. The results showed that Discornin Tablets can promote the expression of κB inhibitory pro-tein, reduce the high expression of NF-κB protein level, and inhibit the cellular secretion of VEGF, MMP-9 and TNF-α. It was concluded that Discornin Tablets had negative regulation effect on nuclear transcription factor κB of RSC-364 cells. It can increase the expression of IκB-α, as well as reduce the secretion of inflammation factors and blood vessel newborn factors. It suggested that Discornin Tablets may have the potential regulation effect on RA.
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This study was aimed to observe the influence of water-solubility nipponica saponin on activation of TNF-α+IL-17-induced rat fibroblast-like synovial cell line RSC-364 cellular model nuclear transcription factor NF-κB pathway as well as TNF-α, IL-1, ICAM-1, MMP-2, MMP-3 secretion. IL-17+ TNF-α were used for stimulating RSC-364 to establish rheumatoid arthritis (RA) cellular model. Water-solubility nipponica saponin in different con-centrations was used for intervention. The influence of water-solubility nipponica saponin in different concentrations on cell viability was detected by semi-quantitative RT-PCR method. Changes in the level of TNF-α, IL-1, ICAM-1, MMP-2, and MMP-3 of culture supernatant were detected by ELISA. The results showed that the activation of NF-κB p65 in RSC-364 stimulated by TNF-α+ IL-17 can be inhibited by water-solubility nipponica saponin ac-cording to its concentration. It improved IκB-α expression, and inhibited TNF-α, IL-1, ICAM-1, MMP-2 and MMP-3 secretion. It was concluded that water-solubility nipponica saponin can inhibit the activation of NF-κB pathway, hinder the secretion and activation of multiple downstream genes, which may be its effect in inhibiting syn-ovial inflammation in RA.
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Objective To investigate the proliferative characteristics of fibroblast-like synovial cells (FLS)in osteoarthritis in vitro and the mechanism of the immunosuppressive effect of total glucusides of paeony(TGP).Methods FLS of OA and non-inflamed synovium(NS)were cultured and identified in vitro in the presence or absence of TGP.After incubation,the survival fraction(SF)of FLS was evaluated by MTI' and the TNF-?,IFN-?and bFGF level in cultured FLS supernatant was measured by ELISA.The expression of FLS c-los mRNA and cell cycle of OA-FLS was observed by RT-PCR and flow eytometry respectively at the same time.Results No statistical significant differences were noted between the OA and NS FLS in pro- liferating double time.High doses of TGP suppressed FLS-SF more evidently in OA patients than in NS(P0.05).Conclusion High dose TGP can inhibit OA-FLS proliferation,modulate cy- tokine secretion and c-fos expression in OA.This suggests that TGP has immunosuppressive effect on OA syn- ovitis,probably by preventing the synovial hypertrophy in OA.
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Objective To investigate the proliferation and differentiation characteristics of fibroblast like synovial cells(FLS)in rheumatoid arthritis(RA)in vitro and the mechanism of the immunosuppressive effect of differentiation inducers, such as all trans retinoid acid(ATRA), ealcitriol [1,25(OH)_2D_3] and dexamethasone(DEX). Methods FLS of knee synovial tissues from RA patients were cultured and identified in vitro in the presence or absence of ATRA, 1,25(OH)_2D_3 and DEX respectively. Synoviocyte proliferation in RA were measured by MTT colorimetrie assay and the survival fraction(SF)of FLS was evaluated. Cell cycle of FLS was observed using fluorescence-activated cell sorting(FCS)method in RA patients. Results The identified synovial cells in patients with RA were FLS(Vimentin and Fibronectin expression was positive), and hadn't been transformed or differentiated to adipocytes and osteoblasts with the three inducers. The SF of all RA-FLS interfered by ATRA, 1,25(OH)_2D_3 and DEX was much lower than that without drugs vehicle group in RA-FLS(P