丝裂原活化蛋白激酶信号通路在类风湿性关节炎发病中的作用研究进展

类风湿性关节炎（RA）是一种常见的自身免疫性疾病，主要特征为滑膜增生和骨侵蚀，最终导致关节畸形而致残。丝裂原活化蛋白激酶（MAPK）信号通路是真核细胞中参与调节细胞有丝分裂、分化和凋亡及炎症和应激反应的重要通路之一，与RA的发生发展密切相关。RA患者关节内细胞因子可与对应受体结合，激活胞内上游调控因子，以三级酶联的方式激活MAPK信号通路。活化的MAPK蛋白通过激活下游转录因子，一方面促进滑膜细胞增生和软骨细胞凋亡，另一方面导致滑膜细胞和软骨细胞中多种基质金属蛋白酶高表达而过度水解细胞外基质，最终造成关节损伤。本文就MAPK信号通路在RA发病中的作用进行综述，以期为RA的基础研究提供参考。     

类风湿关节炎滑膜细胞信号转导机制研究进展

滑膜细胞因子IL 1、TNF α、EGF、TGF β、PDGF、IGF 1在RA发病过程中可活化细胞内两条重要的信号通路 :受体蛋白酪氨酸蛋白激酶 Ras MAPK途径和非受体蛋白酪氨酸蛋白激酶 JAK STAT途径 ,其中受体蛋白酪氨酸蛋白激酶 Ras MAPKs信号转导路径异常是RA慢性滑膜炎的典型特征。研究G蛋白 AC cAMP信号转导通路及该通路与酶偶联受体 Ras MAPKs信号转导通路间的交互联系将具有十分重要的意义。     

以腺苷及其受体信号为靶点的类风湿关节炎疾病和治疗研究进展

类风湿关节炎(RA)是一种慢性自身免疫疾病,目前其发病机制尚未明确,也没有特效药物。新型有效免疫调节药物的发现对RA的有效治疗至关重要。腺苷是一种嘌呤核苷,也是一类重要的免疫调节信号分子,与细胞膜表面的腺苷受体(ARs)结合,ARs为G蛋白偶联腺苷受体有四种亚型,包括A_1AR、A_(2A)AR、A_(2B)AR、A_3AR。被活化的ARs调控促炎细胞因子及抗炎细胞因子释放,从而调节多种免疫细胞功能,参与RA的发生、发展,是RA治疗的潜在靶点。本文围绕腺苷及其受体各亚型在RA发生、发展中作用的研究新进展及针对调节腺苷及受体功能的药物研发新动态进行综述。     

中医药介导OPG/RANK/RANKL信号通路防治类风湿关节炎的研究进展

类风湿关节炎（rheumatoid arthritis, RA）是一种临床常见的以滑膜炎为主的自身免疫性疾病。炎性细胞因子和破骨细胞刺激滑膜组织增生、炎症反应、骨质破坏及关节功能障碍等，在RA的致病因素中占据关键位置。本文对中药单体及其提取物、中药复方及制剂、中药配伍，以及中医治疗通过调控骨保护蛋白（osteoprotegerin,OPG）/NF-κB受体激活因子（receptor activator of NF-κB, RANK）/NF-κB配体激活因子（receptor activator of NF-κB ligand, RANKL）信号通路干预RA的相关研究进行综述。结果表明，中药中的有效分子机制不同，但是可以起到调控信号通路的作用，刺激成骨细胞活性，抑制炎性细胞因子分泌，减少破骨细胞分化，从而防治RA，为中医药多靶点、多途径治疗RA提供理论依据。     

瘦素在类风湿关节炎中的作用机制初步探讨

目的：检测类风湿关节炎（RA）患者血清瘦素水平、滑膜中瘦素及瘦素受体的表达，探讨瘦素在RA发病中的作用机制。方法：RA患者血清标本30例（RA组），以酶联免疫吸附试验（ELISA）测定其血清瘦素浓度；关节滑膜标本25例，用免疫组化的方法测定瘦素及瘦素受体在滑膜中的表达；并与25例骨性关节炎（OA）组和3例正常者（对照组）比较。结果：RA组患者血清瘦素水平明显高于骨性关节炎（OA）组（P〈0．01），也明显高于滑液水平（P〈0．05）；且与体质量指数、a1酸性糖蛋白呈正相关（标准化回归系数分别为0．369及0．234；P〈0．01）；与握力、胰岛素指数及空腹血糖呈负相关（标准化回归系数分别为-0．295、-0．453及-0．192；P〈0．01）；与胰岛素水平、C反应蛋白、类风湿因子（RF）、肿胀指数、压痛指数、晨僵时间、病程、年龄、性别等无关：瘦素及瘦素受体在RA患者滑膜中的表达明显高于正常对照组。结论：瘦素可能通过在靶器官的高表达而起到调节炎症的作用；可能在炎性反应中参与急性时相蛋白的合成与调节而影响疾病的发展过程。     

狄诺塞麦靶向干扰RANK配体通路治疗类风湿关节炎的研究进展

类风湿关节炎（rheumatoid arthritis,RA）是一种系统性自身免疫病,以关节损害和病理性骨量丢失为特征。近年来研究表明,核因子κB受体激活蛋白（receptor activator of nuclear factor κB,RANK）配体（RANK ligand,RANKL）-RANK通路在RA骨损害中起关键作用。人源化单克隆抗体狄诺塞麦（Denosumab,DMab）可特异性结合RANKL,阻断RANKL-RANK通路,起到骨保护作用。DMab作为一种新的治疗手段,对RA患者的局部骨侵蚀和全身性骨质疏松治疗具有明确的理论基础。此文对近5年国内外使用DMab治疗RA的研究进展做一综述。     

调控血脑屏障 ABC转运体信号转导通路的研究现状

血脑屏障中的ABC转运体是介导内源性物质、药物和毒物转运的一类外排转运体,主要包括P－糖蛋白（ P－gp）、多药耐药相关蛋白（ Mrp）以及乳腺癌耐药蛋白（ Bcrp）。这类转运体能限制外来异物进入中枢神经系统,使得很多治疗药物难以透过血脑屏障产生治疗作用,阐明这些转运蛋白的转运机制,可为药物的中枢转运提供新的靶点,有助于降低脑部耐药的发生,改善药物治疗的结局。本文主要针对ABC转运体以及涉及的肿瘤坏死因子－α／蛋白激酶C－β／鞘氨醇1磷酸酯受体1（TNF－α／PKCβ／S1PR1）信号通路、血管内皮生长因子信号通路和雌激素受体信号通路进行探讨。     

STAT3信号通路在胰岛素抵抗中的研究进展 #br#

胰岛素抵抗（IR）是 2型糖尿病的重要发生机制,通过影响多种信号通路传导,从而使糖代谢紊乱,信号传 导与转录激活因子 3（STAT3）通路是一种调控基因转录的重要通路。有证据表明,STAT3信号通路是 IR的关键因 子,能够调节有丝分裂原活化蛋白激酶（MAPK）通路、胰岛素受体底物-1（IRS-1）/磷脂酰肌醇 3激酶（P13K）/蛋白激 酶 B（PKB）通路等胰岛素相关通路。STAT3信号通路被上游细胞因子白细胞介素-22（IL-22）激活,参与糖代谢调 节,目前是研究热点,本文就 STAT3通路与 IR的关系进行综述,旨在进一步阐明糖代谢紊乱机制,为糖尿病治疗提供 新思路。     

巨噬细胞极化对心肌成纤维细胞活化的影响

目的 观察巨噬细胞极化上清对心肌成纤维细胞活化的影响。方法 提取SD大鼠的骨髓细胞和心肌成 纤维细胞。利用巨噬细胞集落刺激因子（M-CSF）处理骨髓细胞后,加入刺激因子：M0（无刺激因子）、M1（100 μg/L脂 多糖+10 μg/L干扰素-γ）、M2（20 μg/L白细胞介素-4）诱导巨噬细胞极化。将极化后的不同型别巨噬细胞及其培养 上清分别与心肌成纤维细胞共培养,分别设空白对照组、M0组、M1组和M2组,通过细胞免疫荧光检测心肌成纤维细 胞中纤维化蛋白的表达水平;实时荧光定量逆转录聚合酶链反应检测巨噬细胞和成纤维细胞特征分子的表达; Western blot检测纤维化相关蛋白及转化生长因子β受体（TGFβR）、血小板衍生生长因子受体（PDGFRs）信号通路活 化情况。结果 经M-CSF及相应刺激因子诱导,成功获得M1和M2型巨噬细胞。细胞共培养结果显示,与M0组相 比,M1组上清培养的心肌成纤维细胞中胶原蛋白1（Col1a1）和Col3a1的mRNA水平以及平滑肌肌动蛋白（α-SMA）表 达水平显著降低（P＜0.05）,而M2组上清培养的心肌成纤维细胞中Col1a1和Col3a1的mRNA水平以及α-SMA、结缔 组织生长因子（CCN2）表达水平显著升高（P＜0.05）。M1组上清培养的心肌成纤维细胞中PDGFRβ蛋白磷酸化水平 显著低于 M0 组（P＜0.01）,而 M2 组上清培养的心肌成纤维细胞中 PDGFRβ 蛋白磷酸化水平显著高于 M0 组（P＜ 0.05）。结论 M1型巨噬细胞上清能够抑制心肌成纤维细胞活化,而M2型巨噬细胞上清能够激活心肌成纤维细胞。 M1型巨噬细胞抑制纤维化的作用可能与抑制PDGFRβ通路的活化有关。     

活化C蛋白样酶的筛选与特性研究Ⅰ.从蛇毒中筛选

活化C蛋白（activated protein C，APC）是人体内重要的生理抗凝剂，对凝血系统、炎症的发生和发展、细胞凋亡等生理反应进行调控。大量动物试验和临床研究表明APC对严重脓毒症、弥散性血管内凝血、婴儿紫斑和脊髓损伤等疾病有显著疗效。Lilly公司开发的重组人APC（商品名Xigris）于2001年由FDA批准上市，是首个治疗成年人严重脓毒症的生物药物。Xigris为新的治疗脓毒症药物的开发，特别为寻找同APC功能相似的天然药物提供了启示。     

Crosstalk between inflammation and coagulation: the lessons of sepsis

Sepsis results in the concurrent activation of inflammatory and procoagulant pathways. Bacterial products and proinflammatory cytokines trigger the coagulation system primarily via induction of tissue factor. During sepsis, activation of coagulation is accompanied by impaired function of major anticoagulant mechanisms, including antithrombin, the protein C system and fibrinolysis. Protease activated receptors (PARs) form the molecular connection between coagulation and inflammation, and especially PAR1 seems to play an eminent role in sepsis pathogenesis. Activated protein C (APC) can cleave PAR1 when associated with either the endothelial protein C receptor (EPCR) or CD11b/CD18, resulting in broad cytoprotective effects mediated by sphingosine 1 phosphate (S1P) receptor 1 (S1P1). In contrast, activation of PAR1 by high dose thrombin results in barrier disruptive effects in endothelial cells via an S1P3 dependent mechanism. Recombinant APC protects against mortality in experimental endotoxemia and sepsis by effects that can be mediated by either EPCR - PAR1 dependent (endothelial cells, dendritic cells) or CD11b/CD18 - PAR1 dependent (macrophages) mechanisms. These protective APC effects do not rely on the anticoagulant properties of this protein. APC mutants that lack anticoagulant properties but retain the capacity to activate PAR1 are promising new drugs for sepsis treatment.     

Anti-thrombotic effect of activated protein C

Protein C (PC) is an important anticoagulant protein in blood and converted to its active form, activated protein C (APC), by thrombin bound with thrombomodulin. APC exhibits an anticoagulant effect by the inactivation of FV a and FVIII a. In addition, APC exerts a profibrinolytic effect by inactivation of PAI-1 and inhibition of TAFI activation. APC is strongly anti-thrombotic because of its anticoagulant and profibrinolytic effect. APC has gamma-carboxyglutamic acid residues that bind to acidic phospholipids expressed on activated platelet or injured endothelial cells. Thus APC works only at the site where clots are formed and has a weak effect in primary hemostasis; this means that the use of APC is expected not to have any hemorrhagic risk. In both DIC animal models and clinical studies, we confirmed safer amelioration by APC than heparin. Recently, a specific receptor for PC/APC was found on endothelial cell membrane and anti-inflammatory effects of APC were also reported. Thus APC is thought to play an important regulatory role in blood coagulation, fibrinolysis and inflammation, especially in thrombotic diseases.     

Protective mechanisms of activated protein C in severe inflammatory disorders

The protein C system is an important natural anticoagulant mechanism mediated by activated protein C (APC) that regulates the activity of factors VIIIa and Va. Besides well-defined anticoagulant properties, APC also demonstrates anti-inflammatory, anti-apoptotic and endothelial barrier-stabilizing effects that are collectively referred to as the cytoprotective effects of APC. Many of these beneficial effects are mediated through its co-receptor endothelial protein C receptor, and the protease-activated receptor 1, although exact mechanisms remain unclear and are likely pleiotropic in nature. Increased insight into the structure–function relationships of APC facilitated design of APC variants that conserve cytoprotective effects and reduce anticoagulant features, thereby attenuating the risk of severe bleeding with APC therapy. Impairment of the protein C system plays an important role in acute lung injury/acute respiratory distress syndrome and severe sepsis. The pathophysiology of both diseases states involves uncontrolled inflammation, enhanced coagulation and compromised fibrinolysis. This leads to microvascular thrombosis and organ injury. Administration of recombinant human APC to correct the dysregulated protein C system reduced mortality in severe sepsis patients (PROWESS trial), which stimulated further research into its mechanisms of action. Several other clinical trials evaluating recombinant human APC have been completed, including studies in children and less severely ill adults with sepsis as well as a study in acute lung injury. On the whole, these studies have not supported the use of APC in these populations and challenge the field of APC research to search for additional answers.This article is part of a themed issue on Mediators and Receptors in the Resolution of Inflammation. To view this issue visit http://www3.interscience.wiley.com/journal/121548564/issueyear?year=2009     

Rosmarinic acid down-regulates endothelial protein C receptor shedding in vitro and in vivo

The endothelial protein C receptor (EPCR) plays pivotal roles in coagulation and inflammation, however, its activity is markedly changed by ectodomain cleavage and release as the soluble protein (sEPCR). According to previous studies, there are approximately 100 ng/ml sEPCR in human plasma and the levels increase in inflammatory diseases. EPCR can be shed from the cell surface, and this is mediated by tumor necrosis factor-α converting enzyme (TACE). We recently reported on the anti-inflammatory and barrier protective activities of rosmarinic acid (RA), an important component of the leaves of Perilla frutescens. However, little is known about the effects of RA on EPCR shedding. Here, we investigated this issue by monitoring the effects of RA on phorbol-12-myristate 13-acetate (PMA), tumor necrosis factor (TNF)-α, and interleukin (IL)-1β, and on cecal ligation and puncture (CLP)-mediated EPCR shedding and underlying mechanisms. Data showed that treatment with RA resulted in potent inhibition of PMA, TNF-α, IL-induced EPCR shedding by suppression of TACE expression. In addition, RA reduced PMA-stimulated phosphorylation of p38, extracellular regulated kinases (ERK) 1/2, and c-Jun N-terminal kinase (JNK). These results suggest the potential for use of RA as an anti-sEPCR shedding reagent against PMA, TNF-α, IL-1β and CLP-mediated EPCR shedding.     

Regulation of VEGF-induced endothelial cell PAF synthesis: role of p42/44 MAPK, p38 MAPK and PI3K pathways

1. Vascular endothelial growth factor (VEGF) is a potent angiogenic and inflammatory mediator. We have recently shown that this latter effect requires the activation of Flk-1 receptor and subsequent endothelial cell (EC) PAF synthesis. However, the intracellular events that regulate EC PAF synthesis upon Flk-1 stimulation by VEGF remain to be elucidated. 2. Using specific inhibitors and Western blot analysis, we herein report that in bovine aortic endothelial cells (BAEC), VEGF induces the synthesis of PAF through the cascade activation of Flk-1 receptor, phospholipase Cgamma (PLCgamma), protein kinase C (PKC) and p42/44 mitogen-activated protein kinases (MAPK). 3. Moreover, we demonstrate that VEGF-mediated PAF synthesis requires the activation of p38 MAPK, likely by directing the conversion of lyso-PAF to PAF. 4. Interestingly, we observed that VEGF also promoted the activation of the phosphatidyl inositol-3-phosphate kinase (PI3K) pathway, and that its blockade potentiated PAF synthesis following a VEGF treatment. Consequently, it appears that the PI3K pathway acts as a negative regulator of EC PAF synthesis. 5. Taken together, these results allow a better understanding of the intracellular events activated upon EC stimulation by VEGF, and shed a new light on the mechanisms by which VEGF induces PAF synthesis.     

Thrombin-stimulated proliferation of cultured human synovial fibroblasts through proteolytic activation of proteinase-activated receptor-1

We examined the mechanism of thrombin on proliferation of synovial fibroblasts obtained from rheumatoid arthritis (RA). Thrombin concentration-dependently induced proliferation of synovial fibroblasts. Proliferation in response to thrombin (10 U/ml) was completely blocked by hirudin. TP367 and TP508, peptides corresponding to 2 noncatalytic regions of thrombin, failed to induce cell proliferation. Thrombin did not induce the production of basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF), and epidermal growth factor (EGF) in synovial fibroblasts. Expression of proteinase-activated receptor (PAR)-1 and PAR-3 mRNAs was observed in synovial fibroblasts. Thrombin and PAR-1 agonist peptide (AP), but not PAR-3 AP, induced intracellular calcium mobilization. PAR-1 AP induced cell proliferation whereas PAR-3 AP and PAR-4 AP had no effect on proliferation. Pertussis toxin (PTX), a Gialpha protein inhibitor; wortmannin, a PI (phosphatidylinositol) 3-kinase inhibitor; and PD98059, a specific MEK [mitogen-activated protein (MAK) kinase kinase] inhibitor, inhibited the thrombin-induced cell proliferation. Furthermore, the proliferation of synovial fibroblasts was suppressed by U-73122, a PLC (phospholipase C) inhibitor; 2-APB, an antagonist of InsP3 (inositol 1,4,5-triphosphate) receptor; and GF-109203X, a PKC (protein kinase C) inhibitor. These results suggest that thrombin induces the proliferation of RA synovial fibroblasts through the activation of PAR-1, leading to the PTX-sensitive G proteins - PI3 kinase pathway and PTX-insensitive G proteins - PLC (InsP3 receptor) Ca(2+)-PKC branch.     

Retinoic acid remodels extracellular matrix (ECM) of cultured human fetal palate mesenchymal cells (hFPMCs) through down-regulation of TGF-β/Smad signaling

The regulation of extracellular matrix (ECM) by retinoic acid (RA) is interesting in light of the fact that the ECM plays an essential role in morphogenesis and palatal shelf elevation. In the current study, we explored the effect of RA overexposure on ECM and the probable mechanisms in cultured human fetal palate mesenchymal cells (hFPMCs). RA dose-dependently inhibited cell proliferation and mRNA and protein levels of ECM components fibronectin, tenascin C and fibrillin-2. Zymography revealed that MMP-2 activity was suppressed by RA. Further analysis revealed that mRNA levels of MMP2 and TIMP2 were decreased, while the MMP2/TIMP2 mRNA ratio was increased, which might facilitate the ECM degradation. Because of the pivotal role of TGF-β/Smad pathway in palatogenesis we therefore checked the effect of RA on TGF-β/Smad signaling. The results indicated RA treatment increased Smad7 expression and decreased the levels of TGF-β1, TGF-β3, TGF-β type II receptor (TβRII) and phosphorylated Smad2 and Smad3. Activation of the Smad pathways by either exogenous TGF-β3 or recombinant adenoviruses for Smad3 attenuated RA-induced inhibition of cell proliferation and ECM components and rescued the RA-altered MMP2/TIMP2 mRNA ratio. In conclusion, these findings suggested that RA overexposure inhibited cell proliferation and disrupted the ECM network through down-regulation of TGF-β/Smad pathway.     

G protein coupled receptors signaling pathways implicate in inflammatory and immune response of rheumatoid arthritis

G protein coupled receptors(GPCRs)are transmembrane receptor proteins,which allow signals to transfer across membrane.GPCRs include a large number of receptors,different receptors mediated different signaling pathways of GPCRs-adenylyl cyclase(AC)-cyclic adenosine 3',5'-monophosphate(c AMP),including β2 adrenergic receptors(β2-ARs)-AC-c AMP signaling pathways,E-prostanoid2/4(EP2/4)-AC-cA MP signaling pathways.Regulatory proteins,such as G protein coupled receptor kinases(GRKs)andβ-arrestins,play important modulatory roles in GPCRs signaling pathway.GPCRs signaling pathway and regulatory proteins implicate the pathogenesis process of inflammatory and immune response.Rheumatoid arthritis(RA)is an autoimmune disease characterized by synovitis and accompanied with inflammatory and abnormal immune response.This article review the advances on GPCRs signaling pathway implicating in the inflammatory and immune response of RA.     

Angiotensin II regulates vascular and endothelial dysfunction: recent topics of Angiotensin II type-1 receptor signaling in the vasculature

Accumulating evidence strongly implicates angiotensin II (AngII) intracellular signaling in mediating cardiovascular diseases such as hypertension, atherosclerosis and restenosis after vascular injury. In vascular smooth muscle cells (VSMCs), through its G-protein-coupled AngII Type 1 receptor (AT(1)), AngII activates various intracellular protein kinases, such as receptor or non-receptor tyrosine kinases, which includes epidermal growth factor receptor (EGFR), platelet-derived growth factor receptor (PDGFR), c-Src, PYK2, FAK, JAK2. In addition, AngII activates serine/threonine kinases such as mitogen-activated protein kinase (MAPK) family, p70 S6 kinase, Akt/protein kinase B and various protein kinase C isoforms. In VSMCs, AngII also induces the generation of intracellular reactive oxygen species (ROS), which play critical roles in activation and modulation of above signal transduction. Less is known about endothelial cell (EC) AngII signaling than VSMCs, however, recent studies suggest that endothelial AngII signaling negatively regulates the nitric oxide (NO) signaling pathway and thereby induces endothelial dysfunction. Moreover, in both VSMCs and ECs, AngII signaling cross-talk with insulin signaling might be involved in insulin resistance, an important risk factor in the development of cardiovascular diseases. In fact, clinical and pharmacological studies showed that AngII infusion induces insulin resistance and AngII converting enzyme inhibitors and AT(1) receptor blockers improve insulin sensitivity. In this review, we focus on the recent findings that suggest the existence of novel signaling mechanisms whereby AngII mediates processes, such as activation of receptor or non-receptor tyrosine kinases and ROS, as well as cross-talk between insulin and NO signal transduction in VSMCs and ECs.