Role of p38 and JNK in liver ischemia and reperfusion

Background/purpose

The signal transduction of mitogen-activated protein kinases (MAPKs) has appeared to be an important mediator of ischemic-related events. Because of this, we analyzed the participation of p38 and JNK in liver ischemia and reperfusion, as two individual members of the MAPK family of proteins.

Methods

All papers referred to in PubMed for the past 15 years were analyzed to determine how and when these MAPKs were considered to be an intricate part of the ischemic event. References were cross-studied to ascertain whether other papers could be found in the literature.

Results

The role of p38 and JNK in liver ischemia was confirmed in the literature. The activation of these mediators was associated with the induction of apoptosis and necrosis. Inhibitors of p38 and JNK reduced the liver ischemia and reperfusion damage, probably through the mechanisms mentioned before.

Conclusions

The development of effective inhibitors of p38 and JNK protein mediators is important for minimizing the harmful effects associated with liver ischemia and reperfusion.     

Role of p38alpha MAPK in cardiac apoptosis and remodeling after myocardial infarction

Acute coronary occlusion results in ischemia-mediated death of cardiomyocytes. In the days and weeks following myocardial infarction (MI), left ventricular remodeling occurs that is characterized by persistent cardiomyocyte apoptosis, thinning and fibrosis at the site of infarction, ventricular chamber dilatation, and growth of remaining viable cardiomyocytes. The p38 mitogen-activated protein kinase (MAPK) signaling cascade has been implicated in the remodeling process. In this work, mice with cardiac-specific expression of a dominant negative mutant form of p38 MAPK (DN-p38alpha) were subjected to MI by occlusion of the left coronary artery. Acute ischemia area was determined by transthoracic echocardiography 2 h after MI surgery, and was found to be nearly identical in DN-p38 mice and their wild-type littermates. Seven days after MI, mice were subjected to repeat echocardiography and histological examination of infarct size. DN-p38 mice had markedly reduced infarct size and increased ventricular systolic function 7 days after MI when compared to wild-type littermates. In addition, DN-p38 mice had less cardiomyocyte apoptosis than wild-type mice in the infarct border zone. Recently, it was discovered that Bcl-X(L) deamidation occurs in vivo, and this results in Bcl-X(L) degradation that sensitizes cells to apoptosis by enhancing BAX activity. Bcl-X(L) deamidation was found to occur in the cardiac tissue of wild-type mice after MI, but was reduced in DN-p38 mice. These results establish that p38 MAPK activity is required for pathological remodeling after MI and suggest that p38 MAPK may promote cardiomyocyte apoptosis through Bcl-X(L) deamidation.     

17-beta-Estradiol decreases p38 MAPK-mediated myocardial inflammation and dysfunction following acute ischemia

Understanding the inflammatory response to myocardial ischemia is an important part of achieving the elusive clinical goal of perfect myocardial protection. While it is established that estrogen affects the chronic inflammatory processes of coronary atherosclerosis, the effects of estrogen on acute myocardial proinflammatory signaling are unknown. To study this, myocardial ischemia and reperfusion was performed in rat hearts from normal adult males, normal adult females, ovariectomized (OVX) females, males supplemented with E2, and OVX females supplemented with E2. Following reperfusion, homogenized hearts were analyzed for TNF-alpha, IL-1beta, and IL-6 gene and protein expression, p38 MAPK activation, and the apoptosis-related proteins caspase-3 and Bcl-2. Hearts from proestrus females demonstrated significantly better post-ischemic functional recovery than males. E2 supplementation to males and OVX females improved post-ischemic myocardial functional recovery, reduced the production of TNF-alpha, IL-1beta and IL-6, and decreased the activation of p38 MAPK and caspase-3 when compared to their untreated counterparts. These results suggest that the effect of estrogen on cardioprotection against myocardial I/R may be attributed to its anti-inflammatory and anti-apoptotic properties. Further understanding of these mechanisms may allow therapeutic manipulation of sex hormones in the treatment of acute ischemic injury.     

人源乳酸杆菌对幽门螺杆菌诱导胃上皮细胞炎症反应的调节及可能通路

目的:探讨人源乳酸杆茵对H pylori诱导SGC7901细胞分泌IL-8及p38MAPK酸化水平的影响.方法:实验分为空白对照组、H pylori刺激组、SB203580干预 H pylori 刺激组和Lac15干预 H pylori刺激组.采用免疫细胞化学法观察该人源乳酸杆菌Lac15对H pylori致SGC7901 细胞p38MAPK磷酸化的影响.ELISA法观察该人源乳酸菌对H pylori致SGC7901细胞分泌IL-8的影响结果:H pylori能诱导细胞的p38MAPK磷酸化水平增高(L4:1.90±0.36 vs 14.01±1.12.P<0.01)以及IL-8分泌量明显增高(27.2616±0.27 ng/L vs 46.3691±0.33 ng/L,P<0.01).预先使用一定浓度(3.0×1011cfu/L,3.0×1010 cfu/L,3.0× 109cfu/L)的人源乳酸杆菌Lac15干预后,p38MAPK磷酸化水平明显降低(IA:4.61±1.13,6.11±0.19,8.25±0.56 vs14.01±1.12,均P<0.01),IL-8分泌量明显降低(42.3209±0.24 ng/L,42.1046±0.23 ng/L,43.4636±0.25 ng/L vs 46.3691±0.33 ng/L,均P<0.05或0.01),与 H pylori 刺激组比较,具有统计学意义.结论:p38MAPK磷酸化参与 H pylori诱导的SGC7901细胞分泌IL-8,人源乳酸杆菌三Lac15可能通过抑制p38MAPK磷酸化途径抑制IL-8的分泌,从而抑制炎症反应.     

吡格列酮预处理对大鼠缺血再灌注心肌细胞凋亡和线粒体超微结构的影响

目的:观察PPARγ激动剂吡格列酮对在体大鼠心肌缺血/再灌注(I/R)心肌细胞凋亡和线粒体超微结构的影响以及其可能机制。方法:将42只SD大鼠随机分为假手术组(对照组)、I/R组、吡咯列酮预处理组(预处理组)。I/R组、预处理组于I/R前24 h分别由尾静脉注射相应溶媒(0.9%氯化钠溶液)及吡格列酮(3 mg/kg)。对照组不结扎前降支,4 h后取出心脏;余2组结扎前降支30 min,再灌注4 h后取出心脏。每组取8只,用透射电镜观察心肌线粒体的超微结构改变,采用TUNEL法和免疫组化法检测各组缺血心肌细胞凋亡和Bcl-2、Bax、caspase-3蛋白的表达,RT-PCR法测p38 MAPK和JNK的mRNA表达;Western blot法测核转录因子-κBp65(NFκB p65)蛋白水平的表达;每组取6只,行心肌梗死面积测定。结果:①与I/R组相比,预处理组线粒体损伤程度明显减轻,梗死面积明显减少;②与I/R组相比,预处理组能明显增加Bcl-2蛋白的阳性细胞指数(P<0.05),降低心肌细胞凋亡率(P<0.05)及Bax、caspase-3蛋白的阳性细胞指数(P<0.05);③与对照组相比,I/R组p38 MAPK和JNK的mRNA表达水平及NFκB p65蛋白表达水平明显增加(P<0.05);与I/R组相比,预处理组能抑制以上水平的过度表达(P<0.05)。结论:吡格列酮预处理可通过保护心肌线粒体结构,减少心肌细胞凋亡起到抗I/R损伤作用,该保护作用机制可能与下调p38 MAPK和JNK的mRNA表达及NFκB p65蛋白表达活性有关。     

p38信号蛋白在乳腺癌组织中表达的研究

目的检测p38信号蛋白在人乳腺癌组织中的表达,探讨其与乳腺癌发展的关系。方法采用免疫组织化学S-P法,检测60例乳腺癌组织中p38信号蛋白的表达。结果38例有淋巴结转移的乳腺癌病例中29例p38表达阳性,阳性率76.3%;22例无淋巴结转移的病例中9例p38阳性表达,阳性率40.9%,两者差异有显著性(P<0.01)。p-p38在有淋巴结转移的病例中阳性率68.4%,在无淋巴结转移的病例中阳性表达率36.4%,差异有显著性(P<0.05)。结论p38信号传导途径在乳腺癌侵袭与转移中起关键作用,其蛋白表达与乳腺癌临床分期有关。     

p38参与单磷酰脂A预处理的延迟保护作用

目的探讨丝裂素活化蛋白激酶p38MAPK是否参与单磷酰脂A(MLA)预处理的延迟保护作用.方法建立大鼠心肌缺血/再灌注损伤(I/R)模型.分别应用MLA、p38的特异性抑制剂SB203580预处理心脏, 24 h后对心脏进行缺血再灌注,观察各组心功能、心肌梗死范围、血浆乳酸脱氢酶(LDH)活性, 同时用Western印迹法检测MLA预处理后即刻、10、15、30 min 、SB203580加单磷酰脂A预处理15 min时p38磷酸化水平.结果 MLA预处理组较I/R组心功能明显改善, 心梗范围明显缩小, 血浆LDH活性升高程度减轻(P<0.01).p38磷酸化在MLA预处理后即刻稍微增高,10 min轻度升高、15 min达到高峰、30 min开始下降, 而用SB203580可明显抑制p38活性, 且预处理延迟保护作用被消除, 分别与单纯缺血再灌注组相似 (P>0.05).结论 MLA预处理对24 h后缺血/再灌注心肌有保护作用.p38参与心肌预处理后的延迟保护作用,MLA预处理后p38适度激活可能是药物延迟保护作用的重要机制之一.     

p38MAPK在大鼠实验性肝纤维化发生中的表达及其意义

目的:观察p38MAPK在实验性大鼠肝纤维化(hepatic fibrosis,HF)发生过程中表达量的变化及其定位,从而揭示p38MAPK信号传导通路与HF形成之间的关系.方法:采用CCl4 sc诱导大鼠HF模型,36R ♂sD大鼠(体质量在180-220 g)随机分为正常对照组(12只)和CCl4造模组(24只),造模3、6、9 wk结束时分别随机处死各组大鼠.取其肝脏观察HF形成过程中不同时间段各组大鼠肝组织病理变化,用RT-PCR技术检测p38MAPKmRNA在造模过程中肝组织中的表达变化,免疫组化方法检测p38MAPK在造模过程中肝组织中蛋白表达量的变化,及其在肝组织中的表达分布情况.结果:与正常对照组比较,CCl4诱导的实验性大鼠HF不同时间段纤维化程度明显加重,随着HF的形成,p38MAPK在mRNA水平和蛋白水平都表现出增加的趋势,并且主要表达于肝脏的间质细胞,肝细胞未见染色.结论:p38MAPK在HF的形成中持续上调,参与HF形成的病理过程,p38MAPK信号传导通路活化可能促进CCl4诱导的HF的形成.     

p38MAPK信号通路与肝缺血再灌注损伤的关系研究

p38MAPK通路参与诸如细胞氧化应激、细胞凋亡和炎症等多种生理和病理过程并在其中起着重要作用。肝缺血再灌注损伤(HIRI)是肝脏外科手术面临的一大难题,由于HIRI发病机制复杂,临床上尚未发现更好的应对HIRI的防治策略。本文就p38MAPK信号通路的主要功能及其在HIRI中的相关作用作一综述,以便为防治HIRI提供一个新的思路。     

川芎嗪对哮喘小鼠p38蛋白激酶及类胰蛋白酶表达的影响

目的探讨川芎嗪对哮喘小鼠p38蛋白激酶（p38MAPK）及类胰蛋白酶表达的影响。方法将30只BALB/c小鼠随机分为3组：A组（对照组）、B组（哮喘组）及C组（川芎嗪组）,每组10只,采用鸡卵清蛋白（OVA）与免疫佐剂（氢氧化铝）腹腔注射致敏及用1%OVA生理盐水溶液雾化激发的方法制备哮喘小鼠模型,C组小鼠于每次激发前1 h腹腔注射川芎嗪（80mg/kg/d）,每天1次,持续5 d,A组腹腔注射等量生理盐水致敏及雾化吸入。行HE染色镜下观察各组肺组织病理改变,并采用免疫组织化学染色SP法半定量测定行肺组织中p38MAPK及类胰蛋白酶表达情况。结果 C组小鼠肺组织HE染色病理改变较B组有减轻,且免疫组化结果显示测定C组小鼠肺组织较B组p38MAPK及类胰蛋白酶MOD有降低（P〈0.05）。结论川芎嗪减轻哮喘气道炎症,部分机制可能是通过影响p38蛋白激酶信号通路及肥大细胞活化实现。     

补阳还五汤对沙鼠前脑缺血再灌注损伤p38MAPK磷酸化、神经细胞凋亡的影响

目的 探讨补阳还五汤对脑缺血再灌注损伤的治疗作用及机制.方法 88只雄性蒙古沙鼠随机分成对照组、模型组、补阳还五汤高、低剂量组.据Kirino法制作沙鼠前脑缺血模型.术后1、6 h,1、3、7 d 尼氏染色观察海马区神经细胞组织形态变化,Western印迹法检测海马区磷酸化p38MAPK的表达,TUNEL法检测凋亡细胞,术后7～13 d八臂迷宫法测试动物学习记忆功能.结果 与对照组比较,脑缺血后海马区神经元结构损伤明显、磷酸化p38MAPK表达水平、凋亡神经细胞数量增加(P＜0.05);大鼠的学习记忆功能下降;与模型组比较,补阳还五汤组大鼠的学习记忆功能得到改善、神经元形态结构损伤减轻、磷酸化p38MAPK蛋白以及神经细胞凋亡数量回降,上述变化在高剂量补阳还五汤组更为明显(P＜0.05).结论 补阳还五汤对脑缺血再灌注损伤有很好的治疗作用,其机制与抑制p38MAPK活化,减少神经细胞凋亡有关.     

p38MAPK-eNOS-N0信号通路在人脐静脉内皮细胞凋亡中的保护作用

目的探讨p38MAPK信号通路在胰高血糖素样肽1(GLP-1)拮抗人脐静脉内皮细胞凋亡中的作用。方法实验分为对照组、糖基化终末产物(AGE)组、GLP-1组、AGE+GLP-1组、AGE+SB203580组、AGE+GLP-1+SB203580组及AGE+GLP-1+L-NAME组,Western blot检测p-p38MAPK/p38MAPK、磷酸化内皮型一氧化氮合酶/内皮型一氧化氮合酶(p-eNOS/eNOS)蛋白表达情况,NO检测试剂盒(一步法)检测NO含量,DCFH-DA荧光探针检测细胞活性氧(ROS)含量,Annexin V/PI流式检测细胞凋亡率。结果与AGE组相比,GLP-1预处理可诱导p-p38MAPK蛋白表达下降(P=0.000);与对照组比较,GLP-1或p38 MAPK抑制剂(SB203580)预处理后,受AGE抑制的eNOS蛋白表达或诱导的ROS水平分别显著升高(P=0.004)或下降(P=0.000);GLP-1预处理后,因AGE诱导的细胞凋亡率显著降低(P=0.000),而加入L-NAME后,GLP-1的抗凋亡作用显著减弱(P=0.002);GLP-1预处理后,细胞NO含量较单纯AGE组明显升高(P=0.000),而予以L-NAME后,细胞NO含量显著降低(P=0.011)。结论GLP-1可抑制p38 MAPK信号通路的活化,拮抗AGE对血管内皮细胞的氧化损伤;上调eNOS蛋白的表达,拮抗AGE诱导的内皮细胞NO生成障碍及细胞凋亡,从而延缓糖尿病合并动脉粥样硬化的发生发展。     

p38MAPK信号转导通路与脑缺血

p38丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)是一类重要的细胞内信号转导通路,其主要作用是参与炎症调节和细胞凋亡.脑缺血时,p38 MAPK被激活,其表达水平以及上游和下游蛋白磷酸化水平均发生改变.缺血预处理可能通过p38 MAPK信号转导通路介导脑缺血后神经细胞的存亡.     

p38MAPK途径在淫羊藿甙促成骨细胞分化中的作用

观察淫羊藿甙对体外培养新生大鼠颅盖骨成骨细胞p38丝裂原活化蛋白激酶(MAPK)蛋白表达的影响,探讨淫羊藿甙防治骨质疏松症的信号转导机制.结果 显示淫羊藿甙可以在5 min内激活p38MAPK途径,并且可以上调Cbfa1蛋白表达和活性升高,加用p38MAPK途径的抑制剂SB203580后可以部分抑制淫羊藿甙对Cbfa1蛋白和活性的上调作用.

Abstract：

This paper was aimed to investigate the effects of icariin on the expression of p38 mitogen activated protein kinase(MAPK)protein in rat osteoblasts cultured in vitro, to elucidate the signal transduction of icariin in preventing and treating osteoporosis. The results showed that p38MAPK could be activated by icariin within 5min, and Cbfal could also be upregulated, and SB203580, an inhibitor of p38MAPK pathway, could partly inhibit Cbfal upregulation by icariin.     

Comparison Between Ischaemic and Anisomycin-Induced Preconditioning: Role of p38 MAPK

To further evaluate the significance of p38 MAPK as trigger or mediator in ischaemic preconditioning, anisomycin and SB 203580 were used to manipulate its activation status. Special attention was given to the concentration of the drugs and protocols used.The isolated perfused rat heart, subjected to either 25 min global ischaemia or 35 min regional ischaemia, was used as experimental model. This was preceded by anisomycin (2 or 5 M: 3 × 5 min; 5 M: 5 min or 10 min; 5 M: 10 min + 10 min washout or 20 M: 20 min) or SB 203580 (2 M: 3 × 5 min; before and during 3 × 5 min or 1 × 5 min ischaemic preconditioning; 10 min). Endpoints were functional recovery during reperfusion and infarct size.Anisomycin, regardless of the protocol, reduced infarct size, but did not improve functional recovery. In a number of experiments activation of JNK by anisomycin was blocked by SP 600125 (10 M). SP 600125 had no effect on the anisomycin-induced reduction in infarct size. SB 203580 when administered for 10 min before sustained ischaemia, improved functional recovery and reduced infarct size. SB 203580 could not abolish the beneficial effects of a multi-cycle preconditioning protocol, but it significantly reduced the outcome of 1 × 5 min preconditioning. In all hearts improved functional recovery and reduction in infarct size were associated with attenuation of p38 MAPK activation during sustained ischaemia-reperfusion.The results indicate that activation of p38 MAPK acts as a trigger of preconditioning, while attenuation of its activation is a prerequisite for improved recovery and a reduction in infarct size.     

p38MAPK在慢性低氧性肺动脉高压中的作用研究进展

肺动脉高压(PH)是一种具有潜在致命性的慢性肺循环疾病,临床表现为右心室后负荷增加,活动耐力下降,严重者可发生循环衰竭而死亡.其病因复杂,可由多种心、肺疾病或肺血管病引起,慢性低氧是PH的一个常见原因.慢性低氧可诱导p38MAPK激活,p38MAPK激活后能增加血管内皮生长因子的表达,血管内皮生长因子能够促进血管内皮细胞迁徙、增殖,从而导致PH的发生.因此,从p38MAPK信号通道角度研究是研究慢性低氧性肺动脉高压发生机制的新方向.     

丹皮酚通过抑制p38 MAPK/N-SMase2通路减少脂多糖诱导的THP-1细胞外泌体分泌

目的探讨丹皮酚抑制脂多糖诱导后THP-1细胞分泌外泌体的作用及机制。方法超速离心法提取外泌体,透射电镜(TEM)观察外泌体形态,Western blot检测标志蛋白Alix、TSG101、CD9和CD63,动态光散射检测外泌体粒径。CCK-8检测细胞存活率,BCA法检测外泌体蛋白量,Western blot检测N-SMase2、p-p38 MAPK蛋白水平。结果超速离心法获得的微囊泡结构物具有完整清晰茶托样膜,直径众数为130 nm,含标志性蛋白Alix、TSG101、CD9和CD63,鉴定为外泌体。丹皮酚(120、60及30μmol/L)可降低脂多糖(1 mg/L)诱导的THP-1细胞分泌外泌体,减少N-SMase2蛋白表达,抑制p38 MAPK磷酸化。结论丹皮酚抑制THP-1细胞外泌体分泌,该作用与抑制p38 MAPK/N-SMase2通路有关。     

Age-induced augmentation of p38 MAPK phosphorylation in mouse lung

The p38 mitogen-activated protein kinase (p38 MAPK) pathway is a key regulator of pro-inflammatory cytokine biosynthesis, which may contribute to the chronic low-grade inflammation observed with aging. We hypothesize that aging up-regulates the activation of p38 MAPK as well as the pro-inflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) in mouse lung, and is accompanied by disturbances in oxidant-antioxidant status. In addition, the elevated protein levels of phosphorylated active form of p38 MAPK (phospho-p38 MAPK) with age are tissue-specific.To test this hypothesis, protein levels of phospho-p38 MAPK were determined using Western blot analysis in isolated lung, brain, heart, spleen, kidney and muscle of young (2-month-old) and aged (20-month-old) male C57BL/6J mice. Results show that phospho-p38 MAPK protein levels, not total-p38 MAPK, increased significantly (p < 0.01, n = 8) in lung and brain of 20-month-old mice. The activation of p38 MAPK in other tissues was not altered with age. Immunostaining showed that epithelial cells and alveolar macrophages in lung parenchyma were the major cellular sources of phospho-p38 MAPK immunity. As measured by enzyme-linked immunosorbent assay (ELISA), TNF-α, IL-1β and IL-6 in lung homogenates were elevated significantly with age, but there were no differences with age in serum levels except for IL-6. In addition, IL-1β and IL-6 were increased notably while TNF-α was not different with age in bronchoalveolar lavage fluid (BALF). Furthermore, the oxidant-antioxidant status was evaluated by measuring pro-oxidant malondialdehyde (MDA) levels and the activity of reactive oxygen species scavenging enzymes (i.e. superoxide dismutase (SOD) and glutathione (GSH)) in lung homogenates. The results showed that SOD and GSH decreased with age, while MDA did not change.In conclusion, our data demonstrate that p38 MAPK is activated during lung aging with a corresponding increase in pro-inflammatory cytokines and decrease in antioxidant capacity.