p38 MAPK信号传导通路及其抑制剂的研究现状

丝裂原活化蛋白激酶（mitogen-activated protein kinases,MAPKs）级联反应是细胞内重要的信号传导系统之一,p38 MAPK信号传导通路是MAPK通路的分支之一,它通过转录因子磷酸化而改变基因的表达水平,参与多种胞内信息传递过程,能对广泛的细胞外刺激发生反应,介导细胞生长、发育、分化及死亡全过程。近年研究发现,p38 MAPK在许多疾病的发病过程中具有重要作用,其抑制剂也在相关疾病的动物模型和临床试验中获得令人可喜的成果。     

p38 MAPK及其抑制剂在子宫内膜异位症中的作用

子宫内膜异位症(EMs)是与炎症有关的雌激素依赖性疾病。p38丝裂原活化蛋白激酶(p38MAPK)受性激素、炎症因子等因素的激活,在细胞凋亡、增殖、炎症、应激等多种细胞反应中起着重要的作用,并直接参与子宫内膜异位症发生发展过程的调控。p38MAPK信号转导通路在性激素和炎症之间的特殊调节作用,将有助于更好地理解子宫内膜异位症错综复杂的病理假说。p38MAPK抑制剂在子宫内膜异位症的研究中发挥重要作用,且前景广阔。在信号通路水平上阻断和调控p38MAPK的表达和活性,有望成为防治子宫内膜异位症的新策略。     

MAPK级联信号通路与长时程增强

长时程增强(long-term potentiation,LTP)被认为是与学习记忆密切相关的神经突触可塑性的生物学基础,多种信号通路参与了LTP的诱导与维持。丝裂原活化蛋白激酶(m i-togen-activated prote in k inases,MAPK)级联信号通路是介导细胞反应的重要信号系统,是细胞外信号从细胞表面传导到细胞核内部的重要传递途径,在细胞的增殖、分化和调亡过程中发挥重要作用。研究表明,MAPK的上游调节物质和下游作用分子在神经元中广泛存在,MAPK级联信号通路通过磷酸化神经元参与LTP诱导与维持的多种受体和酶,进而发挥对LTP的调节作用,影响神经突触可塑性。该文综述了细胞外信号调节激酶(extracellu lar signal-regu lated k inase,ERK)、c-Jun氨基端激酶(c-JunN-term inal k inase,JNK)和p38 3条MAPK通路对LTP的调节作用。     

MAPK信号通路研究进展

丝裂原活化蛋白激酶(MAPK)信号通路是生物体内重要的信号转导系统之一,参与介导细胞生长、发育、分裂和分化等多种生理及病理过程。在哺乳动物细胞中MAPK亚族主要包括ERK1/2,JNK,p38和ERK5,其中ERK5近年来被发现对细胞的生存、增殖、调节血管生成有重要作用,这几条通路之间存在相互"对话"。在传统的信号通路研究方法基础上,蛋白质组学的发展给信号通路研究开辟了一条新的道路。     

p38丝裂原活化蛋白激酶在骨肉瘤的作用机制研究进展

骨肉瘤是临床上常见的一种恶性骨肿瘤,它的特点是肿瘤细胞可直接产生于骨样组织,造成机体骨组织细胞病变,影响患者的骨健康,降低免疫力,威胁患者的生命健康。目前,有调查研究资料显示骨肉瘤好发于青少年人群,且约65%的骨肉瘤患者年龄在25岁以下,男性多于女性。骨肉瘤多发于股骨远端、胫骨近端以及肱骨近端的干骺端部位,常于骨头表面呈现梭形的瘤体,并且多伤及骨膜、骨皮质以及髓腔等部位,影响股骨头的健康,对患者的关节活动范围造成很大的影响。p38丝裂原活化蛋白激酶（p38 mitogen-activated protein kinase,p38 MAPK）是人体内重要的信号物质,能够被MAPK激酶3和MKK6磷酸化从而被激活,进而磷酸化并激活MAPK相关蛋白激酶等,最终激活机体内的转录因子,如ATF-2、Max和MEF2等转录因子,参与调节细胞生长、分化以及炎症反应等重要的细胞生理和病理过程。在骨肉瘤方面,p38 MAPK信号通路能够参与到骨肉瘤的发生、侵袭和转移的过程。本文着重对p38MAPK信号通路在骨肉瘤中的作用机制进行综述。     

MAPK信号转导通路在糖皮质激素耐药白血病中的研究进展

丝裂原活化蛋白激酶(MAPK)信号通路作为信号传递网络中的重要途径之一,在细胞凋亡及生存中发挥重要作用,其中最主要的是ERK、JNK及p38 MAPK途径。近来研究发现,MAPK信号转导通路与白血病的发生发展及耐药的产生有密切关系,将有可能成为白血病治疗的新靶点。本文主要综述了MAPK信号转导通路与白血病发病、治疗作用机制及与糖皮质激素耐药的关系。     

不同阻断剂在人绒毛滋养层细胞中p38MAPK信号传导通路的作用

目的 针对三种不同的阻断剂在人绒毛滋养层细胞中p38MAPK信号传导通路的作用进行比较,探讨人绒毛滋养层细胞受阻断剂对其侵袭性的影响程度.方法 分别对阻断剂影响EMMPRIN表达的程度采用RT-PCR及Western blot方法分别进行观察.人绒毛滋养层细胞在浓度不同佛波酯作用下,对其中p38MAPK活性变化采用ELISA方法进行检测,人绒毛滋养层细胞侵袭作用采用trans well细胞侵入系统进行检测,将浓度不同的p38 MAPK抑制剂加入其中,对阻断剂影响人绒毛滋养层细胞侵袭性的效果进行观察.结果 p38MAPK抑制剂分别由5、10、15及20 μmol·L-1浓度持续24h作用后,对EMMPIRN分别达到7.4％、24.5％、31.7％及39.2％的的抑制率;p38MAPK抑制剂10μmol· L-1浓度进行24h培养后,能够对EMM PRIN基因和蛋白表达具有21.5％的抑制率,培养48h与72h可分别达到45.5％和75.9％的抑制率.分别采用佛波酯0.1、1、10 μmol·L-浓度加入培养细胞中持续30min作用,采用时间剂量依赖方式将p38MAPK激活,p38MAPK抑制剂采用时间剂量依赖方式对佛波酯激活p38MAPK进行抑制.结论 在人绒毛人绒毛滋养层细胞中EMMPRIN表达中体现出p38MAPK信号传导途径,该通路对于侵袭人绒毛滋养层细胞的行为具有重要作用,p38MAPK抑制剂在防治子痫前期-子痫中将发挥重要作用.     

MAPK信号转导途径及其在雌激素作用的研究进展

丝裂原活化蛋白激酶（Mitogen activated protein kinase,MAPK）信号转导途径是真核生物细胞重要的信号转导通路,雌激素可以通过膜受体激活细胞内MAPK（ERK、p38、JNK）信号传导通路引起细胞增殖、分化以及血管扩张等生物学效应和调节细胞凋亡、癌症发生等生命现象。近年来,关于MAPK信号传导途径及雌激素作用的报道逐渐增多,现对相关研究作一综述。     

MAPK信号转导通路与肿瘤细胞凋亡

丝裂原活化的蛋白激酶（mitogen—activated protein kinase,MAPK）是一组可被多种信号激活的丝／苏氨酸激酶。经双重磷酸化激活后可参与细胞的多种生物活性,如调节基因转录,诱导细胞凋亡、调节细胞周期等。而MAPK对细胞凋亡的诱导作用,是近年来研究的重点,尤其是对肿瘤细胞凋亡的诱导作用,更是人们关注的焦点。现已发现p38,ERK5,ERK以及JNK4个亚族。其中ERK,JNK,p38MAPK三条通路与肿瘤细胞凋亡关系密切。细胞凋亡是在特定时空发生的、受机体严密调控的细胞“自杀”现象。在肿瘤细胞中,活化的p38可增强c—myc表达、磷酸化p53、参与Fas／Fasl介导的凋亡;可增强TNF-α表达;作用于Caspase家族的上游而诱导肿瘤细胞凋亡。某些作用丁p38通路的化疗药物,也是通过诱导凋亡,产生抗肿瘤作用。JNK信号转导通路参与多种凋亡反应,现阶段研究表明,JNK通路介导肿瘤细胞凋亡的机制是通过磷酸化Bcl-2和Bcl-xL,促进线粒体释放细胞色素C,进而激活Caspase级联反应,最终作用于Caspase-3,导致细胞凋亡。     

TLR4-p38MAPK信号通路在金黄色葡萄球菌感染人巨噬细胞系U937过程中的表达及意义

目的观察金黄色葡萄球菌感染人巨噬细胞系U937细胞后信号通路Toll样受体4(TLR4)-p38蛋白激酶(p38MAPK)的表达及意义。方法体外培养人巨噬细胞系U937细胞,感染0、30、60和90 min时收集细胞,应用Western blot法检测各组TLR4和p38MAPK蛋白表达的变化;在另一实验中,分为对照组、金黄色葡萄球菌感染60 min组及p38MAPK抑制剂SB203580 5 mg/m L干预组、SB203580 10 mg/m L干预组,应用Western blot法检测各组TLR4和p38MAPK蛋白表达的变化。结果随着感染时间的延长,TLR4和p38MAPK蛋白的表达逐渐增加;给予SB203580抑制剂后,TLR4和p38MAPK蛋白的表达明显减弱。结论金黄色葡萄球菌感染U937细胞可引起TLR4-p38MAPK信号通路的活化,而SB203580对其有明显的抑制作用,证明TLR4-p38MAPK信号通路与金黄色葡萄球菌感染U937细胞密切相关。     

Involvement of the p38 MAPK signaling pathway in S‐phase cell‐cycle arrest induced by Furazolidone in human hepatoma G2 cells

Given the previously described essential role for the p38 mitogen‐activation protein kinase (p38 MAPK) signaling pathway in human hepatoma G2 cells (HepG2), we undertook the present study to investigate the role of the p38 MAPK signaling pathway in cell‐cycle arrest induced by Furazolidone (FZD). The aim of this study was to determine the effects of FZD on HepG2 cells by activating and inhibiting the p38 MAPK signaling pathway. The cell cycle and proliferation of HepG2 cells treated with FZD were detected by flow cytometry and MTT assay in the presence or absence of p38 MAPK inhibitors (SB203580), respectively. Cyclin D1, cyclin D3 and CDK6 were detected by quantitative real‐time PCR and western blot analysis. Our data showed that p38 MAPK became phosphorylated after stimulation with FZD. Activation of p38 MAPK could arise S‐phase cell‐cycle arrest and suppress cell proliferation. Simultaneously, inhibition of the p38 MAPK signaling pathway significantly prevented S‐phase cell‐cycle arrest, increased the percentage of cell viability and decreased the expression of cyclin D1, cyclin D3 and CDK6. These results demonstrated that FZD arose S‐phase cell‐cycle arrest via activating the p38 MAPK signaling pathway in HepG2 cells. Cyclin D1, cyclin D3 and CDK6 are target genes functioning at the downstream of p38 MAPK in HepG2 cells induced by FZD. Copyright © 2012 John Wiley & Sons, Ltd.     

Inhibition of transforming growth factor (TGF)-beta1-induced extracellular matrix with a novel inhibitor of the TGF-beta type I receptor kinase activity: SB-431542

Transforming growth factor beta1 (TGF-beta1) is a potent fibrotic factor responsible for the synthesis of extracellular matrix. TGF-beta1 acts through the TGF-beta type I and type II receptors to activate intracellular mediators, such as Smad proteins, the p38 mitogen-activated protein kinase (MAPK), and the extracellular signal-regulated kinase pathway. We expressed the kinase domain of the TGF-beta type I receptor [activin receptor-like kinase (ALK)5] and the substrate, Smad3, and determined that SB-431542 is a selective inhibitor of Smad3 phosphorylation with an IC50 of 94 nM. It inhibited TGF-beta1-induced nuclear Smad3 localization. The p38 mitogen-activated protein kinase inhibitors SB-203580 and SB-202190 also inhibit phosphorylation of Smad3 by ALK5 with IC50 values of 6 and 3 microM, respectively. This suggests that these p38 MAPK inhibitors must be used at concentrations of less than 10 microM to selectively address p38 MAPK mechanisms. However, the p38 MAPK inhibitor SB-242235 did not inhibit ALK5. To evaluate the relative contribution of Smad signaling and p38 MAPK signaling in TGF-beta1-induced matrix production, the effect of SB-431542 was compared with that of SB-242235 in renal epithelial carcinoma A498 cells. All compounds inhibited TGF-beta1-induced fibronectin (FN) mRNA, indicating that FN synthesis is mediated in part via the p38 MAPK pathway. In contrast, SB-431542, but not the selective p38 MAPK inhibitor SB-242235, inhibited TGF-beta1-induced collagen Ialpha1 (col Ialpha1). These data indicate that some matrix markers that are stimulated by TGF-beta1 are mediated via the p38 MAPK pathway (i.e., FN), whereas others seem to be activated via ALK5 signaling independent of the p38 MAPK pathway (i.e., col Ialpha1).     

Mycotoxin patulin activates the p38 kinase and JNK signaling pathways in human embryonic kidney cells.

Patulin (PAT), a mycotoxin mainly produced by Penicillium and Aspergillus, is frequently detected in moldy fruits and fruit products. Exposure of human embryonic kidney (HEK293) cells to PAT led to a dose- and time-dependent increase in the phosphorylation of two major mitogen-activated protein kinases (MAPKs), p38 kinase and c-Jun N-terminal kinase (JNK). The phosphorylated forms of MAPK kinase 4 (MKK4), c-Jun, and ATF-2 were also seen in PAT-treated cultures. The cell death caused by PAT was significantly reduced by the p38 kinase inhibitor, SB203580, but not by the JNK inhibitor, SP600125. Neither p38 kinase nor JNK played a role in the PAT-induced DNA damage. In PAT-treated cells, inactivation of double-stranded RNA-activated protein kinase R (PKR) by the inhibitor, adenine, markedly suppressed JNK and ERK phosphorylation. Treatment of HEK293 cells with PAT-cysteine adduct, a chemical derivative of PAT, showed no effect on MAPK signaling pathways, cell viability, or DNA integrity. These results indicate that PAT causes rapid activation of p38 kinase and JNK in HEK293 cells, but only the p38 kinase signaling pathway contributes to the PAT-induced cell death. PKR also plays a role in PAT-mediated MAPK activation.     

Amyloid beta peptide-activated signal pathways in human platelets

Amyloid beta peptide (amyloid-beta), which accumulates in the cerebral microvessels in an age-dependent manner, plays a key role in the pathogenesis of cerebral amyloid angiopathy. Platelets are an important cellular element in vasculopathy of various causes. Amyloid-beta may activate or potentiate platelet aggregation. The present study explored the signaling events that underlie amyloid-beta activation of platelet aggregation. Platelet aggregometry, immunoblotting and assays to detect activated cellular events were applied to examine the signaling processes of amyloid-beta activation of platelets. Exogenous amyloid-beta (1-2 microM) potentiated platelet aggregation caused by collagen and other agonists. At higher concentrations (5-10 microM), amyloid-beta induced platelet aggregation which was accompanied by an increase in thromboxane A2 (TxA2) formation. These amyloid-beta actions on platelets were causally related to amyloid-beta activation of p38 mitogen-activated protein kinase (MAPK). Inhibitors of p38 MAPK and its upstream signaling pathways including proteinase-activated receptor 1 (PAR1), Ras, phosphoinositide 3-kinase (PI3-kinase), or Akt, but not extracellular signal-regulated kinase 2 (ERK2)/c-Jun N-terminal kinase 1 (JNK1), blocked amyloid-beta-induced platelet activation. These findings suggest that the p38 MAPK, but not ERK2 or JNK1 pathway, is specifically activated in amyloid-beta-induced platelet aggregation with the following signaling pathway: PAR1 --> Ras/Raf --> PI3-kinase --> Akt --> p38 MAPK --> cytosolic phospholipase A2 (cPLA2)--> TxA2. In conclusion, this study demonstrates amyloid-beta activation of a p38 MAPK signaling pathway in platelets leading to aggregation. Further studies are needed to define the specific role of amyloid-beta activation of platelets in the pathogenesis of vasculopathy including cerebral amyloid angiopathy.     

Targeting mitogen-activated protein kinases for asthma

Allergic asthma is a chronic airway inflammatory disorder attributable to T-helper 2 cell responses together with other inflammatory cells such as mast cells, B cells and eosinophils, and pro-inflammatory cytokines and chemokines. Mitogen-activated protein kinase (MAPK) signaling cascades have been shown to be important in the differentiation, activation, proliferation, degranulation and migration of various immune cells, and airway smooth muscle and epithelial cells. In mammal, MAPK signaling modules are divided into at least 3 groups: extracellular signal-regulated kinase (ERK), p38 MAPK, and c-Jun NH2-terminal kinase (JNK). Each MAPK module plays a discrete yet complementary role in accentuating allergic airway inflammation. Cumulative evidence reveals potential anti-inflammatory activities of MAPK inhibitors in a variety of in vitro models of inflammation. Recently, the anti-inflammatory effects of MAPK kinase inhibitor (U0126), p38 MAPK inhibitors (SB239063 and respirable p38alpha MAPK antisense oligonucleotide) and JNK inhibitor (SP600125) have been demonstrated in in vivo animal models of asthma. Development of inhibitors targeting at MAPK could be an attractive strategy for the treatment of asthma.     

Selective pharmacological inhibitors reveal differences between Thy-1- and T cell receptor-mediated signal transduction in mouse T lymphocytes

A compelling body of evidence suggests a role for Thy-1 (CD90), a cell surface glycoprotein of mouse T lymphocytes, in signal transduction resulting in T cell activation. Despite more than 3 decades of investigation, intracellular biochemical events governing the Thy-1 signaling cascade are only vaguely understood. We have employed selective pharmacological inhibitors of signaling molecules to compare downstream elements participating in the Thy-1 signal transduction pathway with those involved in the T cell receptor (TCR)/CD3-associated signaling pathway. Mitogenic anti-Thy-1 or anti-CD3 monoclonal antibody (mAb) were used to cause T cells from C57BL/6 mice to proliferate in the presence or absence of different pharmacological inhibitors. Cyclosporine A, herbimycin A, LY294002, calphostin C and PD98059 all inhibited anti-Thy-1-induced T lymphocyte proliferation, indicating the involvement of calcineurin, protein tyrosine kinases, phosphatidylinositol 3-kinase, protein kinase C, and MEK1 (MAPK kinase 1), respectively, in Thy-1 signaling. Similar results were obtained when T cells were stimulated through the TCR with anti-CD3 monoclonal antibody in the presence or absence of the different inhibitors. Interestingly, the p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 augmented anti-Thy-1-induced T cell proliferation, whereas anti-CD3-induced proliferative response was partially suppressed by the same inhibitor. The Thy-1 signal transduction pathway, therefore, shares a requirement for calcineurin and several major kinase families with the TCR signaling pathway. However, Thy-1 and TCR-associated signaling pathways are differentially regulated by p38 MAPK.     

The p38 MAPK inhibitors for the treatment of inflammatory diseases and cancer

Background: The p38 mitogen-activated protein kinase (MAPK) is activated by various pro-inflammatory and stressful stimuli. Mounting evidence suggests that the p38 MAPK signaling cascade is involved in various biological responses other than inflammation such as cell proliferation, differentiation, apoptosis and invasion, suggesting that the p38 MAPK can serve as a potential therapeutic target for the treatment of not only inflammatory diseases but also cancer. Methods: The unique characteristics of p38 MAPK are summarized with regard to activation and function of p38 MAPK signaling cascades. We then discuss the involvement of p38 MAPK in diseases and the implications of the possible therapeutic use of p38 MAPK inhibitors. The p38 MAPK inhibitors that have been used in the in vitro/in vivo systems as well as in the clinical trials are summarized. Results/conclusion: The p38 MAPK plays an important role in key cellular processes related to inflammation and cancer. Understanding the signal transduction mechanisms and gene regulation by p38 MAPK provides useful information in the development of p38 MAPK inhibitors with therapeutic benefits with reduced side effects. In this review, we summarize and present the list of p38 MAPK inhibitors in in vitro/in vivo studies as well as in clinical trials.     

Nectandrin A Enhances the BMP-Induced Osteoblastic Differentiation and Mineralization by Activation of p38 MAPK-Smad Signaling Pathway

Osteoblastic activity of nectandrin A was examined in C2C12 cells. Nectandrin A enhances the BMP-induced osteoblastic differentiation and mineralization, manifested by the up-regulation of differentiation markers (alkaline phosphatase and osteogenic genes) and increased calcium contents. In C2C12 cells co-transfected with expression vector encoding Smad4 and Id1-Luc reporter, nectandrin A increased Id1 luciferase activity in a concentration-dependent manner, when compared to that in BMP-2 treated cells, indicating that Smad signaling pathway is associated with nectandrin A-enhanced osteoblastic differentiation in C2C12 cells. In addition, nectandrin A activated p38 mitogen-activated protein kinase (MAPK) in time- and concentration-dependent manners, and phosphorylated form of pSmad1/5/8 and alkaline phosphatase activity were both decreased when the cells were pretreated with SB203580, a p38 MAPK inhibitor, suggesting that p38 MAPK might be an upstream kinase for Smad signaling pathway. Taken together, nectandrin A enhances the BMP-induced osteoblastic differentiation and mineralization of C2C12 cells via activation of p38 MAPK-Smad signaling pathway, and it has a therapeutic potential for osteoporosis by promoting bone formation.