成纤维样滑膜细胞在类风湿关节炎发病机制中的作用

类风湿关节炎的发病过程非常复杂,与遗传、免疫、环境等因素密切相关,其发病机制尚未被阐明.成纤维样滑膜细胞是血管翳交界处最常见的细胞类型,在类风湿关节炎的发生、发展中发挥重要作用.从成纤维样滑膜细胞的角度入手,探讨当前类风湿关节炎的相关作用机制.研究认为成纤维样滑膜细胞介导的炎症反应、血管翳生成、骨破坏,是类风湿关节炎形...     

银杏素促进成纤维样滑膜细胞中TRAF3蛋白的表达缓解类风湿关节炎

目的 探究银杏素(ginkgetin)治疗类风湿关节炎(rheumatoid arthritis,RA)的潜在机制.方法 通过TNF-α刺激成纤维样滑膜MH7A细胞建立炎性细胞模型,用银杏素单独处理或分别与TNF受体相关因子3(tumor necrosis factor receptor-associated fact...     

类风湿关节炎成纤维样滑膜细胞体外增殖活性的研究

目的研究类风湿关节炎成纤维样滑膜细胞(RA-FLS)的体外增殖活性。方法收集行关节腔镜术或关节置换术的RA、骨关节炎(OA)、关节创伤患者的膝关节滑膜组织标本各3例,应用酶消化法进行FLS的分离培养,采用MTT法比较三种来源细胞的体外增殖活性。结果 RA-FLS在体外培养第3、4、5天时OD值较OA、关节创伤来源者增高(P值均小于0.05)。结论 RA-FLS细胞增殖程度较OA、关节创伤来源者增高。     

造影剂激活p38信号通路诱导肾小管细胞凋亡

目的探讨丝裂素激活蛋白激酶(MAPK)信号通路在造影剂诱导的肾小管细胞凋亡中的作用。方法培养大鼠肾小管细胞(NRK-52E),分别加入不同种类和浓度的造影剂刺激,部分实验同时加入SB203580(p38MAPK抑制剂)。台盼蓝排除试验检测细胞膜完整性。流式细胞仪DNA分析、FITC-AnnexinⅤbinding/PI染色以及电镜扫描检测细胞凋亡。Western印迹分析和免疫沉淀法检测MAPK的磷酸化水平和活性。结果高渗性造影剂泛影葡胺可诱导NRK-52E细胞凋亡,并且,在一定的渗透浓度范围内,随着渗透浓度的升高,细胞凋亡率越高;在一定的时间范围内,随着时间的延长,细胞凋亡率也越高。低渗性造影剂欧乃派克在实验浓度范围内则不能诱导NRK-52E细胞凋亡。泛影葡胺刺激NRK-52E细胞15min后,p38MAPK磷酸化水平及活性便明显增加,并持续至60min,120min时磷酸化水平及活性明显降低,几乎回到零水平。总的p38MAPK水平在整个实验期间内几乎无变化。SB203580可明显抑制泛影葡胺诱导的NRK-52E细胞凋亡。p44/p42MAPK的磷酸化水平在整个实验阶段则无明显变化。结论造影剂呈渗透浓度和时间依赖性诱导NRK-52E细胞凋亡,造影剂诱导细胞凋亡与其高渗有关。p38MAPK信号通路的激活介导了造影剂诱导的NRK-52E细胞凋亡。     

老年性骨关节炎与类风湿关节炎滑膜细胞转化特性的比较研究

目的与骨关节炎比较,探讨类风湿关节炎(rheumatoid arthritis,RA)成纤维样滑膜细胞(fibroblast-like synoviocytes,FLS)胞外信号活化蛋白激酶(ERK)的活化状态和P53蛋白的异常表达。方法原代培养RA FLS和OA FLS,应用western blot检测二者ERK活化状态的差异;应用抗P53抗体(DO-1和PAb240)与抗PCNA抗体对RA和OA的滑膜组织和细胞进行免疫组织化学染色;并进一步应用western blots确定RA FLS P53的异常表达。结果与OA相比,RA滑膜衬里层P53蛋白表达增多,主要为与抗突变型P53抗体阳性反应细胞积聚,并进一步证实RA衬里层成纤维样滑膜细胞P53表达异常;而且RA FLS在低血清和非贴壁情况下ERK活化状态均明显高于骨关节炎。结论类风湿关节炎衬里层成纤维样滑膜细胞P53蛋白异常表达,而且ERK处于持续活化状态,这为RAFLS的转化特性提供了新的佐证。     

类风湿关节炎滑膜成纤维细胞增殖及巨自噬的表达水平

目的:探讨体外原代培养的类风湿关节炎滑膜成纤维细胞(RA-FLS)中是否存在巨自噬现象以及在类风湿关节炎(RA)中的发病机制.方法:培养原代RA-FLS,以骨关节炎(OA)患者膝关节滑膜组织中培养的骨关节炎滑膜成纤维细胞(OA-FLS)作为对照组.采用MTT法检测细胞增殖活力;流式细胞仪检测细胞凋亡;采用实时荧光定量聚...     

大黄素抗类风湿关节炎的作用机制研究进展

类风湿关节炎是一种累及关节的自身免疫性疾病,临床表现为关节炎症、骨损伤和软骨破坏、关节功能障碍和畸形,以及关节外的器官损伤。近年来,天然药物治疗类风湿关节炎的研究取得了显著的成果,大黄素是中药大黄的主要活性成分之一,具有良好的抗炎和抗氧化等作用。筛选近年来实验方法科学、研究方向新颖的文献,总结大黄素抗类风湿关节炎的作用机制,发现大黄素可通过减轻炎症反应、促进软骨细胞的增殖分化、抑制软骨细胞凋亡、延缓软骨细胞外基质降解等途径显示出抗类风湿关节炎的潜力。     

类风湿关节炎滑膜成纤维细胞通过高表达RANKL促进破骨细胞分化及活化

目的探讨类风湿关节炎滑膜成纤维细胞（RA-FLS）对破骨细胞（Oc）分化和活化的作用及机制。方法活动期RA滑膜体外分离培养FLS,以骨关节炎（OA）-FLS为对照,分别与健康人外周血单核细胞（MNC）共培养后,抗酒石酸酸性磷酸酶（TRAP）染色鉴定Oc并计数、甲苯胺蓝染色观察骨吸收陷窝情况。细胞免疫荧光染色检测FLS RANKL表达,Real-time PCR及W estern blot检测RANKL和OPG mRNA、蛋白表达。结果 RA-FLS与MNC共培养7 d时TRAP＋且细胞核≥3个的Oc很少,14 d时见较多的Oc,21 d甲苯胺蓝染色示清晰的骨吸收陷窝,而OA-FLS与MNC共培养后未见Oc,也未见骨吸收陷窝。细胞免疫荧光染色示RA-FLS较OA-FLS高表达RANKL（P〈0.05）。RA-FLS RANKL mRNA和蛋白表达较OA-FLS明显增高,而OPG mRNA和蛋白表达则明显降低,RANKL/OPG mRNA和蛋白比率较OA-FLS明显增高（均P〈0.05）。结论 RA-FLS可能通过高表达RANKL,促进外周血MNC向Oc分化,并促进Oc的骨吸收功能。     

电针调控lncRNA NEAT1减轻类风湿关节炎滑膜成纤维细胞炎症反应的研究

目的：观察电针对调控lncRNA NEAT1减轻类风湿关节炎大鼠滑膜成纤维细胞炎症反应的影响。方法：将16只2月龄大鼠应用随机数字表法分为空白对照组和电针组,每组8只。空白对照组大鼠未接受干预,电针组大鼠予以电针干预,分别制备空白对照组、电针组血清。予以连续酶消化法获取3周龄SD大鼠滑膜成纤维细胞,波形蛋白免疫组化染色进行鉴定;再将6孔板中已培养的滑膜成纤维细胞随机分为空白对照组、模型对照组、电针组成纤维细胞。空白对照组成纤维细胞予以空白对照组血清干预,模型对照组成纤维细胞予以含10 ng·mL^-1白细胞介素-1β(IL-1β)的空白对照组血清诱导滑膜成纤维细胞致炎,电针组成纤维细胞予以含10 ng·mL^-1 IL-1β的电针组血清干预。Real-time PCR检测各组滑膜成纤维细胞中lncRNA NEAT1水平变化;Western blot检测各组滑膜成纤维细胞基质金属蛋白酶-3(MMP-3)、V-Rel网状内皮增生病毒癌基因同源物A(RELA)、肿瘤坏死因子-α(TNF-α)蛋白表达含量。结果：经波形蛋白免疫组化染色后,大鼠滑膜成纤维细...     

重组Furin蛋白对类风湿关节炎滑膜细胞生物学行为的影响

[目的]探讨重组弗林蛋白(Furin)对于类风湿性关节炎(rheumatoid arthritis,RA)滑膜细胞增殖、迁移、侵袭和细胞因子分泌的影响。[方法]从类风湿关节炎患者关节内提取RA滑膜组织后培养原代滑膜成纤维细胞(fibroblast-like synovial cells,FLS);将重组Furin蛋白按照不同浓度(250 ng/ml,500 ng/ml)加入RA滑膜细胞培养基中诱导培养并采用MTT、细胞划痕、Transwell、ELISA等方法检测重组蛋白处理对细胞增殖、迁移、侵袭和炎性因子分泌等生物学特性的影响。[结果]与空白对照组比,加入重组Furin蛋白处理24 h、48 h,对类风湿滑膜细胞增殖活动没有明显影响(P>0.05)。处理24 h后与空白对照组比,迁入划痕伤口内细胞数无显著区别(P>0.05),滑膜细胞穿透基底膜细胞数明显减少(P<0.05),且与剂量浓度呈正相关。培养液上清中IL-1α和IL-17含量升高(P<0.05),而各组间IL-1β和TNF-α含量差异无统计学意义(P>0.05)。[结论]重组Furin蛋白诱导可抑制类风湿关节炎滑膜细胞侵袭能力同时可促进其分泌IL-1α和IL-17。     

Methylglyoxal induces apoptosis through activation of p38 mitogen-activated protein kinase in rat mesangial cells

BACKGROUND: The formation of methylglyoxal (MG), a highly reactive dicarbonyl compound, is accelerated through several pathways, including the glycation reaction under diabetic conditions, presumably contributing to tissue injury in diabetes. On the other hand, apoptotic cell death of glomerular cells has been suggested to play a role in the development of glomerulosclerosis in various types of glomerular injuries. We therefore examined whether MG was capable of inducing apoptosis in rat mesangial cells to address the possible mechanism by which hyperglycemia-related products accelerated pathologic changes in diabetic glomerulosclerosis. METHODS: Rat mesangial cells were incubated with 0 to 400 micromol/L MG, followed by the detection of apoptosis by both TUNEL method and electrophoretic analysis for DNA fragmentation. In addition, we investigated intracellular mechanisms mediating MG-induced apoptosis, focusing especially on the p38 mitogen-activated protein kinase (MAPK) pathway. RESULTS: MG induced apoptosis in rat mesangial cells in a dose-dependent manner and was accompanied by the activation of p38alpha isoform. Aminoguanidine and N-acetyl-l-cysteine inhibited the MG-induced p38 MAPK activation, as well as apoptosis in rat mesangial cells, suggesting the involvement of oxidative stress in these phenomena. SB203580, a specific inhibitor of p38 MAPK also suppressed the MG-induced apoptosis in rat mesangial cells. CONCLUSIONS: These results suggest a potential role for MG in glomerular injury through p38 MAPK activation under diabetic conditions and may serve as a novel insight into the therapeutic strategies for diabetic nephropathy.     

Homocysteine induces mesangial cell apoptosis via activation of p38-mitogen-activated protein kinase

Hyperhomocysteinemia is prevalent among patients with chronic kidney disease (CKD) and has been linked to progressive kidney and vascular diseases. Increased glomerular mesangial cell (MC) turnover, including proliferation and apoptosis, is a hallmark of CKD. Activation of p38-mitogen-activated protein kinase (p38-MAPK) has been linked to apoptosis in many cell lines. Accordingly, we studied the effect of homocysteine (Hcy) on MC p38-MAPK signalling and apoptosis. Hcy (50 microM/24 h) increased MC apoptosis as determined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP) nick end labelling (TUNEL) and single-stranded DNA (ssDNA) analysis. In addition to increases in pro-caspase-3 protein and caspase-3 activity, cells exposed to Hcy manifested enhanced reactive oxygen species content. Hcy increased p38-MAPK activity (fivefold), with maximal effect at 50 microM and 20 min; p38-MAPK activation was attenuated by N-acetylcysteine (Nac) and catalase (Cat), further indicating that the effect was via oxidative stress. Confocal microscopy revealed activation and nuclear translocation of p38-MAPK that was attenuated by Cat. In addition, Hcy-induced apoptosis as determined by TUNEL and ssDNA assay was abrogated by Nac, Cat, and SB203580 (p38-MAPK inhibitor). We conclude that in MC, Hcy (i) activates p38-MAPK and increases p38MAPK nuclear translocation via an oxidative stress dependent mechanism and (ii) induces DNA damage and apoptosis that is dependent on oxidative stress and p38-MAPK activation.     

Sphingosine 1-phosphate induces heat shock protein 27 via p38 mitogen-activated protein kinase activation in osteoblasts.

We previously showed that sphingosine 1-phosphate acts as a second messenger for tumor necrosis factor alpha-induced interleukin-6 synthesis in osteoblast-like MC3T3-E1 cells and that the synthesis by sphingosine 1-phosphate is dependent on p42/p44 mitogen-activated protein (MAP) kinase activation. In the present study, we investigated the effect of sphingosine 1-phosphate on the induction of heat shock protein 27 (HSP27) in MC3T3-E1 cells. Not C2-ceramide, but sphingosine and sphingosine 1-phosphate significantly induced HSP27 accumulation dose dependently in the range between 1microM and 30 microM. DL-threo-dihydrosphingosine, an inhibitor of sphingosine kinase, markedly inhibited the sphingosine-induced HSP27 accumulation. Sphingosine 1-phosphate induced increase in the levels of the mRNA for HSP27. Sphingosine 1-phosphate stimulated the phosphorylation of p38 MAP kinase. The sphingosine 1-phosphate-induced HSP27 accumulation was dose dependently suppressed by SB203580, an inhibitor of p38 MAP kinase, but not PD98059, an inhibitor of the upstream kinase that activates p42/p44 MAP kinase. SB203580 reduced the sphingosine 1-phosphate-induced increase of mRNA for HSP27. These results strongly suggest that sphingosine 1-phosphate-stimulated HSP27 induction is mediated via p38 MAP kinase activation in osteoblasts.     

RHAMM induces progression of rheumatoid arthritis by enhancing the functions of fibroblast-like synoviocytes

Background

Rheumatoid arthritis (RA) is a chronic and refractory autoimmune joint disease. Fibroblast-like synoviocytes (FLS) produce inflammatory cytokines and are involved in the migration and invasion of panuus tissue, which leads to the destruction of joints in RA. Receptor for hyaluronan mediated motility (RHAMM), is known to be one of the important receptors for hyaluronic acid. It has the ability to regulate migration of fibrocytes and infiltration of inflammatory cells. Here,we explored the mechanisms of RHAMM in RAFs.

Methods

Quantitative PCR and western blot were performed to test the expression of RHAMM in synoviocytes of RA patients and osteoarthritis (OA) controls. Collagen antibody-induced arthritis (CAIA) was used to investigate the RHAMM expression in mouse synovial issues. RHAMM siRNA was used to detect the function of RHAMM in FLS.

Results

RA-FLS has a significantly higher expression of RHAMM than OA-FLS. Expression of RHAMM in joint synovial tissue was markedly increased in the CAIA mice compared with the controls. RHAMM silencing using SiRNA was not only decreased the production of IL-6 and IL-8, but also inhibited the migration and invasion of RA-FLS.

Conclusions

RHAMM has an important role in the FLS induced modulation of inflammation and destruction of joints in RA.

     

Mycophenolic acid induces islet apoptosis by regulating mitogen-activated protein kinase activation

Mycophenolic acid (MPA), an inosine monophosphate dehydrogenase inhibitor, is widely used as an immunosuppressive drug after transplantations including those of pancreas islet cells. However, recent reports have indicated that MPA has apoptotic effects on islet cells in vitro. To study the effect of MPA on islet cells and determine its mechanism, we used an insulin secreting cell-line, HIT-T15. We examined mitogen-activated protein kinase (MAPK) activation after MPA treatment, and determining cell death levels using methylthiazdetetrazolium assays. The activations of extracellular signal-regulated protein kinase (ERK), c-jun N-terminal kinase (JNK), and p38 MAPK and caspase-3 cleavage were measured by Western blotting. MPA (1, 10, 30 micromol/L) increased cell death and caspase-3 cleavage within 24 hours. Exogenous 500 micromol/L guanosine reversed the MPA-induced islet cell death, but exogenous adenosine did not. MPA 10 micromol/L induced cell apoptosis and increased the activations of JNK, ERK, and p38 MAPK. Furthermore, exogenous guanosine, but not exogenous adenosine, reversed these effects induced by MPA. This study demonstrated that MPA may induce islet apoptosis in HIT-T15 cells by increasing activations of JNK, ERK, and p38 MAPK in a guanosine-dependent manner.     

The role of p38alpha mitogen-activated protein kinase activation in renal fibrosis

The p38 mitogen-activated protein kinase (MAPK) pathway transduces external stress stimuli and is important in extracellular matrix synthesis in cell types in vitro; however, its role in renal fibrosis is not known. Explored was the role the p38 MAPK pathway in rat unilateral ureteric obstruction (UUO), a model of renal fibrosis induced by a noninflammatory surgical insult. In a time-course study, a marked increase in phosphorylation (activation) of p38 in both interstitial myofibroblasts and tubules was shown. Rats were then treated daily with a specific inhibitor of p38alpha, NPC 31169, from the time of UUO surgery until being killed 7 d later. Compared with vehicle, NPC 31169-treated rats had a significant reduction in renal fibrosis assessed by interstitial volume, collagen IV deposition, and mRNA levels. This was primarily due to a reduction in the accumulation of interstitial myofibroblasts, as shown by a reduction in the area of immunostaining for alpha-smooth muscle actin and heat shock protein 47. The increase in renal TGF-beta1 mRNA and protein levels in UUO was unaltered with NPC 31169 treatment; however, connective tissue growth factor mRNA was reduced. These results demonstrate that p38alpha MAPK plays an important role in renal fibrosis, acting downstream of TGF-beta1. Blockade of p38 MAPK reduces extracellular matrix production and may be considered a potential therapeutic option in the treatment of renal fibrosis.     

Gallic acid,a natural polyphenolic acid,induces apoptosis and inhibits proinflammatory gene expressions in rheumatoid arthritis fibroblast-like synoviocytes

ObjectivesTo investigate whether gallic acid (3, 4, 5-trihydroxybenzoic acid), a natural polyphenolic acid found in gall nuts, sumac, oak bark, tea leaves, grapes and wine, has pro-apoptotic and anti-inflammatory effects on fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis (RA).MethodsViability of RA FLS was assessed using a MTT assay after gallic acid treatment. Apoptosis was assessed by TUNEL assay and caspase-3 activity was determined by a colorimetric assay. The levels of apoptosis-related proteins including Bcl-2, p-Akt, p53, and Bax were determined using western blot analyses, and the mRNA expressions of various pro-inflammatory mediators were measured using quantitative real-time PCR.ResultsCell viability of RA FLS was significantly decreased by treatment with 10 or more μM of gallic acid. Gallic acid treatment at the concentrations that do not affect cell viability (0.1 and 1 μM) induced cellular apoptosis of RA FLS. Treatment with 0.1 and 1 μM of gallic acid also resulted in a significant increase in caspase-3 activity and regulated the productions of Bcl-2, Bax, p53 and pAkt. The mRNA expression levels of pro-inflammatory cytokines (IL-1β, IL-6), chemokines (CCL-2/MCP-1, CCL-7/MCP-3), cyclooxygenase-2, and matrix metalloproteinase-9 from RA FLS were suppressed by the gallic acid treatment in dose-dependent manners.ConclusionGallic acid treatment was found to induce apoptosis of RA FLS through regulation of apoptosis-related protein expressions and to reduce the expression of pro-inflammatory genes in RA FLS. These data suggest that pro-apoptotic and anti-inflammatory activities of gallic acid may be used as a possible therapeutic option for RA.