一氧化氮通过环磷酸鸟苷激活细胞外信号调节激酶/P90RSK 信号通路在大鼠脑缺血再灌注损伤中的作用

目的:观察大鼠脑缺血再灌注损伤时诱导型一氧化氮合酶源性一氧化氮、细胞外信号调节激酶激酶/细胞外信号调节激酶的信号转导通路,分析神经细胞损伤之间的联系。方法:实验于2005-03/2006-03在中国医科大学第一临床学院麻醉实验室完成。32只Wistar大鼠随机摸球法分为4组,即对照组、模型组、诱导型一氧化氮合酶抑制剂组、细胞外信号调节激酶激酶抑制剂组,每组各8只。采用4血管阻断法制作大鼠全脑缺血再灌注模型,对照组行假手术。诱导型一氧化氮合酶抑制剂组、细胞外信号调节激酶激酶抑制剂组夹闭两侧颈总动脉前30min分别腹腔注射N-3-苯甲基-乙脒(诱导型一氧化氮合酶特异性抑制剂)45μmol/kg或SL327(细胞外信号调节激酶激酶特异性抑制剂)100mg/kg,对照组和模型组腹腔注射等量生理盐水。缺血20min再灌注24h后处死大鼠取海马,检测大鼠海马组织中一氧化氮、环磷酸鸟苷量的变化及诱导型一氧化氮合酶mRNA和细胞外信号调节激酶1/2、P90RSK蛋白表达水平;电镜观察海马线粒体的变化。结果:Wistar大鼠32只全部纳入结果分析。①模型组大鼠海马中一氧化氮、环磷酸鸟苷的量、诱导型一氧化氮合酶mRNA水平比对照组增高[(0.42±0.03),(0.21±0.02)μmol/g;(44.7±4.1),(19.6±1.8)nmol/L;1.07±0.04,0.25±0.02;P<0.01];诱导型一氧化氮合酶抑制剂组、细胞外信号调节激酶激酶抑制剂组大鼠海马中一氧化氮、环磷酸鸟苷、诱导型一氧化氮合酶mRNA水平比模型组降低[(0.31±0.02),(0.44±0.03)μmol/g;(29.5±2.4),(46.3±4.2)nmol/L;0.70±0.03,1.10±0.04;P<0.01]。②模型组大鼠海马中细胞外信号调节激酶1/2,P90RSK蛋白表达水平较对照组升高;诱导型一氧化氮合酶抑制剂组、细胞外信号调节激酶激酶抑制剂组较模型组降低(P<0.01)。③电镜观察模型组大鼠海马线粒体变性率比对照组升高(P<0.01),诱导型一氧化氮合酶抑制剂组和细胞外信号调节激酶激酶抑制剂组大鼠海马线粒体变性率比模型组低(P<0.01)。结论:脑缺血再灌注损伤时,诱导型一氧化氮合酶源性的一氧化氮可能通过环磷酸鸟苷激活了细胞外信号调节激酶激酶/细胞外信号调节激酶/P90RSK信号转导通路诱导了神经细胞的损伤。     

电针对脑缺血再灌注大鼠海马区胰岛素样生长因子-1表达的影响

目的 观察电针对大脑中动脉缺血再灌注大鼠缺血脑组织海马区神经细胞凋亡及胰岛素样生长因子-1（IGF—1）的影响。方法 采用大脑中动脉线栓法制备大脑中动脉闭塞（MCAO）再灌注模型，分别应用TUNEL染色法、免疫组化法观察脑缺血再灌注及电针对大鼠缺血脑组织海马区神经细胞凋亡及IGF-1的影响。结果 脑缺血再灌注后大鼠缺血侧海马CA1区凋亡细胞数显著增多（模型组与正常组、假手术组比较，P〈0．01），IGF-1阳性表达数目少量增加，胞浆染色呈轻-中度阳性（模型组与正常组、假手术组比较，P〈0．05），电针组大鼠缺血侧海马CA1区的凋亡细胞数减少，IGF-1的阳性表达数目增加，胞浆染色呈中-强阳性（电针组与模型组比较，P〈0．01）。结论 电针可降低大鼠缺血侧海马CA1区的凋亡细胞数，增强IGF-1的阳性表达；早期电针治疗对脑缺血损害的有效防治作用，可能是通过上调IGF-1表达、抑制神经元凋亡的机制实现的。     

一氧化氮通过环磷酸鸟苷激活细胞外信号调节激酶／P^90RSK信号通路在大鼠脑缺血再灌注损伤中的作用

目的：观察大鼠脑缺血再灌注损伤时诱导型一氧化氮合酶源性一氧化氮、细胞外信号调节激酶激酶／细胞外信号调节激酶的信号转导通路，分析神经细胞损伤之间的联系。 方法：实验于2005-03／2006-03在中国医科大学第一临床学院麻醉实验室完成。32只Wistar大鼠随机摸球法分为4组，即对照组、模型组、诱导型一氧化氮合酶抑制剂组、细胞外信号调节激酶激酶抑制剂组，每组各8只。采用4血管阻断法制作大鼠全脑缺血再灌注模型，对照组行假手术。诱导型一氧化氮合酶抑制剂组、细胞外信号调节激酶激酶抑制剂组夹闭两侧颈总动脉前30min分别腹腔注射N-3-苯甲基-乙脒（诱导型一氧化氮合酶特异性抑制剂）45μmol／kg或SL327（细胞外信号调节激酶激酶特异性抑制剂）100mg／kg，对照组和模型组腹腔注射等量生理盐水。缺血20min再灌注24h后处死大鼠取海马，检测大鼠海马组织中一氧化氮、环磷酸鸟苷量的变化及诱导型一氧化氮合酶mRNA和细胞外信号调节激酶1／2、p^90RSK蛋白表达水平；电镜观察海马线粒体的变化。 结果：Wistar大鼠32只全部纳入结果分析。①模型组大鼠海马中一氧化氮、环磷酸鸟苷的量、诱导型一氧化氮合酶mRNA水平比对照组增高[（0．42&;#177;0．03），（0．21&;#177;0．02）μmol／g；（44．7&;#177;4．1），（19．6&;#177;1．8）nmol／L：1．07&;#177;0．04，0．25&;#177;0．02；P〈0．01]；诱导型一氧化氮合酶抑制剂组、细胞外信号调节激酶激酶抑制剂组大鼠海马中一氧化氮、环磷酸鸟苷、诱导型一氧化氮合酶mRNA水平比模型组降低[（0．31&;#177;0．02），（0．44&;#177;0．03）μmol／g；（29．5&;#177;2．4），（46．3&;#177;4．2）nmol／L；0．70&;#177;0．03，1．10&;#177;0．04；P〈0．011。②模型组大鼠海马中细胞外信号调节激酶1／2，p^90RSK蛋白表达水平较对照组升高；诱导型一氧化氮合酶抑制剂组、细胞外信号调节激酶激酶抑制剂组较模型组降低（P〈0．01）。③电镜观察模型组大鼠海马线粒体变性率比对照组升高（P〈0．01），诱导型一氧化氮合酶抑制剂组和细胞外信号调节激酶激酶抑制剂组大鼠海马线粒体变性率比模型组低（P〈0．01）。 结论：脑缺血再灌注损伤时，诱导型一氧化氮合酶源性的一氧化氮可能通过环磷酸鸟苷激活了细胞外信号调节激酶激酶／细胞外信号调节激酶/p^90RSK信号转导通路诱导了神经细胞的损伤。     

脑缺血再灌注后Src激酶抑制剂PP2对神经元保护机制的探讨

目的探讨Src激酶抑制剂PP2在大鼠脑缺血再灌注后对神经元延迟性死亡保护作用的机制。方法建立Wistar大鼠全脑缺血再灌注动物模型,分为无缺血再灌注正常空白对照组(sham),Src激酶抑制剂PP2实验组(PP2)和Src激酶抑制剂PP2类似物的实验对照组(PP3)。实验组及实验对照组Wistar大鼠在双侧颈动脉夹闭造成全脑缺血前30分钟于脑室内分别注射PP2和PP3,控制大鼠脑组织缺血时间均为10min,再灌注时间均为72h。于再灌注时取出大鼠脑组织,部分脑组织通过甲醛固定后行HE染色观察每组大鼠海马CA1区神经元存活数量;另外部分脑组织在-20℃环境下将丘脑背外侧皮层脑组织分离,并应用差速离心法分离出神经元,通过Western Blot分析神经元组分中Src激酶、NMDA受体及PSD蛋白的磷酸化变化情况。结果通过HE病理切片发现,在成功建立了大鼠全脑缺血再灌注动物模型中海马CA1区神经元出现延迟性死亡的现象,大鼠海马CA1区神经元死亡数量PP2实验组的明显少于PP3实验对照组。Western Blot分析结果显示:与空白对照组比较,实验组及实验对照组神经元出现缺血延迟性死亡时NMDAR2B、NMDAR2A、PSD93及Src激酶的磷酸化表达明显升高(P0.001);实验组与实验对照组比较,Src激酶抑制剂PP2可显著下调脑缺血再灌注后NMDAR2B、NMDAR2A、PSD93及Src激酶的磷酸化表达(P0.01)。结论脑缺血再灌注后Src激酶抑制剂PP2可以对神经元起到保护作用,其机制可能与NMDAR2B、NMDAR2A、PSD93及Src磷酸化表达水平的改变有关。     

电针对脑缺血再灌注大鼠学习记忆能力及RhoA蛋白表达的影响

目的探讨电针神庭、百会穴对脑缺血再灌注模型大鼠学习记忆能力的影响及其可能机制。方法 45只雄性Sprague-Dawley大鼠随机分为假手术组(n=15)、模型组(n=15)和电针组(n=15)。模型组和电针组均采用左侧大脑中动脉缺血(MCAO)再灌注模型。电针组电针神庭、百会穴共7 d。采用Morris水迷宫测试观察大鼠学习记忆能力;尼氏染色观察大鼠海马神经元形态结构变化;Western blotting法检测大鼠左侧海马Rho A蛋白的表达。结果与模型组相比,电针组学习记忆能力改善(P0.05),海马神经元损伤减少(P0.05),海马组织中Rho A蛋白表达降低(P0.05)。结论电针能够改善脑缺血再灌注大鼠学习记忆能力,其机制可能与抑制Rho A蛋白表达有关。     

脊髓损伤模型大鼠神经修复与法舒地尔和RhoA基因沉默的干预

背景:研究认为Rho激酶可致使神经生长锥塌陷,对神经修复具有抑制作用。目的:观察Rho激酶抑制剂法舒地尔及RNA干预介导的RhoA基因沉默对脊髓损伤大鼠在体神经损伤修复的作用。方法:雄性SD大鼠60只半切法制成脊髓半横断模型,随机等分成对照组、法舒地尔组和RhoA siRNA组。法舒地尔组于腹腔注射10mg/kg法舒地尔,2次/d,连续用药1周;RhoA siRNA干扰组将RhoA siRNA表达质粒注射于大鼠脊髓损伤区。结果与结论:伤后4周,法舒地尔和RhoA siRNA组大鼠后肢运动功能均有明显恢复,可见少量神经轴索样结构,辣根过氧化物酶阳性神经纤维数增多(P<0.05),体感诱发电位的潜伏期明显缩短、波幅显著增强(P<0.05)。提示大鼠脊髓损伤后给予Rho激酶抑制剂法舒地尔及RNA介导的RhoA基因沉默能够促进受损伤的脊髓神经功能恢复。     

脊髓损伤模型大鼠神经修复与法舒地尔和RhoA基因沉默的干预

背景：研究认为Rho激酶可致使神经生长锥塌陷,对神经修复具有抑制作用。目的：观察Rho激酶抑制剂法舒地尔及RNA干预介导的RhoA基因沉默对脊髓损伤大鼠在体神经损伤修复的作用。方法：雄性SD大鼠60只半切法制成脊髓半横断模型,随机等分成对照组、法舒地尔组和RhoA siRNA组。法舒地尔组于腹腔注射10mg/kg法舒地尔,2次/d,连续用药1周;RhoA siRNA干扰组将RhoA siRNA表达质粒注射于大鼠脊髓损伤区。结果与结论：伤后4周,法舒地尔和RhoA siRNA组大鼠后肢运动功能均有明显恢复,可见少量神经轴索样结构,辣根过氧化物酶阳性神经纤维数增多（P〈0.05）,体感诱发电位的潜伏期明显缩短、波幅显著增强（P〈0.05）。提示大鼠脊髓损伤后给予Rho激酶抑制剂法舒地尔及RNA介导的RhoA基因沉默能够促进受损伤的脊髓神经功能恢复。     

法舒地尔对急性心肌梗死大鼠血流动力学及相关蛋白表达的影响

[目的]探讨法舒地尔对急性心肌梗死（AMI）大鼠血流动力学及相关蛋白表达的影响.[方法]取雄性Wistar大鼠,结扎左前降支建立AMI 动物模型,术后24 h存活的大鼠随机分为AMI组、低分子肝素组和法舒地尔组.再随机选取10只大鼠作为假手术组,只在左前降支下穿线不结扎.低分子肝素组4 μL/kg腹腔注射;法舒地尔组给予法舒地尔5 mg/ kg 腹腔注射,2次/日;AMI组和假手术组给予等量生理盐水.4周后分别测血流动力学指标：左心室收缩压（LVSP）、左心室舒张末压（LVEDP）、左心室内压最大上升和下降速率（ ＋ dp/ dtmax、- dp/ dtmax）;western blot检测Caspase-3、Bax及Bcl-2表达的变化.[结果]AMI组大鼠血流动力学指标与假手术组相比,差异有显著性（P〈0.05）.与AMI组相比,低分子肝素组和法舒地尔组大鼠血流动力学指标改善,相关蛋白Bcl-2 表达增加,Caspase-3、Bax表达减少,差异均有显著性（P〈0.05）.[结论]Rho激酶参与了AMI后心肌细胞凋亡及心力衰竭的进展,法舒地尔通过抑制Rho激酶的表达减少细胞凋亡,保护缺血心肌,延缓心力衰竭进程.     

脑缺血再灌注糖尿病大鼠海马CA1区凋亡基因的表达

目的 观察凋亡基因Bcl-2、Bax在糖尿病大鼠脑缺血再灌注海马CA1区神经元损伤中的表达。方法 采用链脲佐菌素（STZ）诱导和线栓法制备糖尿病大脑中动脉闭塞模型（MCAO）,应用HE染色和免疫组化方法比较糖尿病脑缺血再灌注组与缺血再灌注组海马CA1区神经元缺失、凋亡基因Bcl-2、Bax的表达。结果 糖尿病脑缺血再灌注组海马CA1区神经元缺失,明显高于缺血再灌注组（P〈0.05）;缺血再灌注组及糖尿病脑缺血再灌注组大鼠海马CA1区Bcl-2、Bax阳性染色阳性细胞与正常对照组及假手术组比增多,差异显著（P〈0.05）,而糖尿病脑缺血再灌注组比缺血再灌注组增加得更明显,差异有显著性（P〈0.05）,其中Bax上调幅度大。结论 糖尿病大鼠脑缺血再灌注损伤后海马CA1区细胞发生凋亡,Bcl-2、Bax介导的细胞凋亡机制可能是糖尿病加重脑缺血再灌注海马神经元损伤机制之一。     

西洛他唑对慢性脑缺血大鼠学习记忆能力的影响

目的观察慢性脑缺血致大鼠学习记忆功能及西洛他唑对其的影响。方法结扎大鼠双侧颈总动脉（2VO）建立慢性脑缺血模型。雄性Wistar大鼠随机分为假手术组、缺血组和西洛他唑组,每组又分为3、6、9周三个时间点;应用Morris水迷宫评定不同时期大鼠认知功能,通过HE染色观察神经细胞形态学改变。结果Morris水迷宫表明,各时间点西洛他唑组和假手术组大鼠游迷宫平均潜伏期均明显低于缺血组（P〈0.05）;HE染色显示假手术组和西洛他唑组皮层、海马CA1区神经元缺血性改变较缺血组改变轻,6、9周较3周给药组缺血改变明显。结论西洛他唑能改善慢性脑缺血大鼠的学习记忆能力,可能通过减轻神经元损伤作用改善慢性脑缺血大鼠学习记忆障碍。     

法舒地尔和RhoA沉默对神经干细胞增殖的影响

背景：Rho及其相关分子在神经轴突生长、分化、延伸及突触形成中起重要作用,阻断和抑制RhoA/ROCK通路可促进神经干细胞的增殖与生长。目的：观察Rho激酶抑制剂法舒地尔和RNAi介导的RhoA基因沉默对大鼠神经干细胞增殖的影响。方法：体外培养Wistar胎鼠神经干细胞,分6组干预：空白对照组,5,10,15,20μmol/L法舒地尔组,siRNA沉默RhoA基因组。干预后第3天,采用RT-PCR,Westernblot检测各组神经干细胞RhoA基因及蛋白的表达。应用MTT比色法观察神经干细胞增殖情况;采用流式细胞术测定神经干细胞周期分布的变化。结果与结论：15,20μmol/L法舒地尔组、siRNA沉默RhoA基因组神经干细胞RhoA基因及蛋白表达量较5,10μmol/L法舒地尔组、空白对照组明显降低（P〈0.05）,细胞的生长速度较5,10μmol/L法舒地尔组、空白对照组明显增快（P〈0.05）,细胞周期G0/G1期减少（P〈0.05）,S期细胞数增多（P〈0.05）。当法舒地尔浓度增加到20μmol/L时对细胞的作用并非随浓度的增加而增强,与15μmol/L组的差异无显著性意义（P〉0.05）。15,20μmol/L法舒地尔组与siRNA沉默RhoA基因组相比差异无显著性意义（P〉0.05）。说明Rho激酶抑制剂法舒地尔和RNAi介导的RhoA基因沉默在体外均能促进神经干细胞增殖,法舒地尔最佳作用浓度为15μmol/L。     

盐酸法舒地尔对老年急性脑梗死患者神经功能缺损评分的影响

目的 探讨Rho激酶抑制剂盐酸法舒地尔治疗老年急性脑梗死患者的临床疗效.方法 选择符合入选标准的急性期老年脑梗死患者,随机分入治疗组和对照组,每组各48例.在常规治疗基础上治疗组应用法舒地尔进行治疗,对照组应用盐酸川芎嗪进行治疗,根据治疗前及治疗后第7天、第14天神经功能缺损评分观察临床治疗效果,应用相关分析.结果 两组治疗第7天时神经功能缺损评分有显著改善(P<0.05或P<0.01),但治疗组第14d疗效更为明显,与对照组相比差异有统计学意义(P<0.01).治疗组显效率达62.50%(30/48),对照组显效率45.83%(22/48),两组间显效率相比差异有统计学意义(P<0.05).结论 老年脑梗死患者急性期应用法舒地尔可有效改善神经功能缺损评分,临床疗效明显.     

The Rho kinase inhibitor fasudil inhibits tumor progression in human and rat tumor models

The ability of cancer cells to undergo invasion and migration is a prerequisite for tumor metastasis. Rho, a Ras-related small GTPase, and the Rho-associated coiled coil-containing protein kinases (Rho kinases, ROCK1 and ROCK2) are key regulators of focal adhesion, actomyosin contraction, and thus cell motility. Inhibitors of this pathway have been shown to inhibit tumor cell motility and metastasis. Here, we show that fasudil [1-(5-isoquinolinesulfonyl)-homopiperazine], an orally available inhibitor of Rho kinases, and its metabolite 1-(hydroxy-5-isoquinoline sulfonyl-homopiperazine) (fasudil-OH) modify tumor cell morphology and inhibit tumor cell migration and anchorage-independent growth. In addition, we show that fasudil inhibited tumor progression in three independent animal models. In the MM1 peritoneal dissemination model, tumor burden and ascites production were reduced by > 50% (P < 0.05). In the HT1080 experimental lung metastasis model, fasudil decreased lung nodules by approximately 40% (P < 0.05). In the orthotopic breast cancer model with MDA-MB-231, there were 3-fold more tumor-free mice in the fasudil-treated group versus saline control group (P < 0.01). Fasudil has been approved for the treatment of cerebral vasospasm and associated cerebral ischemic symptoms. In patients, fasudil is well tolerated without any serious adverse reactions. Therefore, the concept of Rho kinase inhibition as an antimetastatic therapy for cancer can now be clinically explored.     

Central role of rho kinase in lipopolysaccharide-induced platelet capture on venous endothelium.

BACKGROUND: Platelet-endothelial cell interactions play a key role in hemostasis and pathological coagulation and are dependent on different surface molecules that are expressed upon activation (eg, mediated by lipopolysaccharide [LPS]). Recently, we have shown that Rho kinase plays a central role in LPS-mediated leukocyte-endothelial cell interactions. We investigated the role of Rho-kinase in inflammatory interactions between platelets and the endothelium in femoral veins in vivo. METHODS: Mice were injected intravenously with LPS (0.5 mg/kg)/D-galactosamine (900 mg/kg), and Rho kinase was blocked with fasudil 15 minutes before LPS application. Four hours after LPS administration, intravital fluorescence microscopy of the femoral vein was performed, and primary and secondary platelet-endothelial cell interactions were visualized after in vivo platelet staining with rhodamine 6G. RESULTS: Intravital microscopy showed a significant increase in platelet tethering, rolling, and firm adhesion as well as platelet secondary capture in LPS-treated mice. Rho-kinase inhibition by fasudil significantly reduced platelet tethering, rolling, and firm adhesion. Interestingly, functional blockade of Rho kinase was also able to diminish secondary platelet capture by 79%. CONCLUSIONS: From our data, we conclude that Rho-kinase signaling plays a central role in the regulation of LPS-induced platelet-endothelial cell interactions in large veins in vivo. Thus, Rho-kinase inhibition might be useful in prevention or treatment of pathological inflammation and endotoxin-mediated hypercoagulation.     

Fasudil and ozagrel in combination show neuroprotective effects on cerebral infarction after murine middle cerebral artery occlusion

Rho kinase (ROCK), one of the serine/threonine kinases, is involved in pathologic conditions, and its activation causes neuronal cell death. Fasudil, a selective ROCK inhibitor, has been reported to cause increased cerebral blood flow (CBF) in the ischemic brain and protect against neuronal cell death by inhibiting ROCK. Ozagrel, a thromboxane A(2) synthase inhibitor, inhibits platelet aggregation and causes vasodilatation, thereby increasing CBF in cerebral thrombosis. The present study evaluates the combination therapy of fasudil and ozagrel on focal brain ischemia induced by middle cerebral artery occlusion (MCAO) in mice. Each monotherapy of fasudil at 10 mg/kg i.p. and ozagrel at 30 mg/kg i.p. significantly reduced cerebral infarction. The combination therapy of fasudil (3 mg/kg i.p.) and ozagrel (10 mg/kg i.p.), which are noneffective doses, resulted in reduction of cerebral infarction, and the protective effect was observed up to 5 min, but not 3 h, after reperfusion. Regional CBF after MCAO and phosphorylation of endothelial nitric-oxide synthase (NOS) significantly increased in response to the combination therapy, whereas these effects were not observed with monotherapy of either drug. The protective effect of combination treatment was antagonized by the treatment of a NOS inhibitor, nitro-l-arginine methyl ester hydrochloride. These findings indicate that the combination treatment of fasudil and ozagrel exhibits additive effects for neuroprotection after MCAO. These findings indicate that the combination treatment of fasudil and ozagrel may be useful as a potential therapeutic strategy for the treatment of stroke.     

Rho kinase inhibition by fasudil attenuates cyclosporine-induced kidney injury

It has been shown that the inhibition of the Rho/Rho kinase (ROCK) pathway prevents tubulointerstitial fibrosis and ameliorates renal function in various progressive renal disorders. The present study was to determine whether fasudil, a ROCK inhibitor, has a protective effect on cyclosporine A (CsA)-induced nephropathy. Male Sprague-Dawley rats were treated with CsA (n = 10, 20 mg · kg(-1) day(-1) s.c.), CsA + fasudil (n = 10, 3 mg · kg(-1) day(-1) i.p.), or vehicle alone (n = 10) for 28 days. Fasudil cotreatment ameliorated CsA-induced changes and restored renal function. CsA decreased the expression of endothelial nitric-oxide synthase and increased inducible nitric-oxide synthase/3-nitrotyrosine in the kidney. Accordingly, there was infiltration of inflammatory cells and up-regulation of inflammatory cytokines. Fasudil also significantly suppressed the expression of transforming growth factor-β1, Smad signaling, and subsequent epithelial-to-mesenchymal processes. In addition, fasudil augmented p27(kip1) expression and decreased the number of proliferating cell nuclear antigen-positive cells. In another series of experiments using HK-2 cells in culture, fasudil also suppressed CsA-induced increases in mitogen-activated protein kinase phosphorylation. CsA induced expression of p53, the degree of which was attenuated by fasudil in association with decreases of proapoptotic markers such as Bad, Bax, and total/cleaved caspase-3. These results suggest that inhibition of the Rho/ROCK pathway attenuates CsA-induced nephropathy through the suppression of the induction of inflammatory, apoptotic, and fibrogenic factors, along with inhibition of Smad, mitogen-activated protein kinases, and nitric oxide signaling pathways.     

Rho kinase inhibition by fasudil suppresses lipopolysaccharide-induced apoptosis of rat pulmonary microvascular endothelial cells via JNK and p38 MAPK pathway

Apoptosis of microvascular endothelial cells plays a crucial role in the progression of various lung diseases and triggers microcirculatory disorder and organ dysfunction. LPS, an outer membrane component of Gram-negative bacteria, is one of the major virulence factors for lung diseases. Recent studies have shown that the Rho/Rho kinase (ROCK) pathway plays an important role in the regulation of apoptosis, inflammatory cell migration and chemokine production in various cell types and animal models. We therefore undertake this study to investigate the inhibitory effect of fasudil, a potent and selective inhibitor of ROCK, on LPS-induced apoptosis of rat pulmonary microvascular endothelial cells (PMVECs). The results suggested that fasudil effectively prevented LPS-induced injury of rat PMVECs, as determined by MTT assay, LDH activity assay, apoptosis and western blot analysis of apoptosis-related proteins Bcl-2 and Bax. Furthermore, the mechanisms underlying the protective effect were evaluated. We found that LPS-induced MYPT-1 phosphorylation was markedly suppressed by fasudil. Moreover, fasudil pretreatment obviously inhibited the activation of JNK and p38 MAPKs induced by LPS, whereas that of ERK1/2 was not affected by fasudil. In addition, inhibiting the JNK and p38 pathways by SP600125 and SB203580 respectively attenuated the LPS-induced apoptosis and regulated the expression of apoptosis-related proteins Bcl-2 and Bax. Taken together, these results demonstrate that fasudil exerts an anti-apoptotic effect in rat PMVECs, which is mediated by the inhibition of Rho/ROCK and its downstream JNK and p38 MAPKs.     

Fasudil-induced hypoxia-inducible factor-1alpha degradation disrupts a hypoxia-driven vascular endothelial growth factor autocrine mechanism in endothelial cells

Hypoxic response of endothelial cells (EC) is an important component of tumor angiogenesis. Especially, hypoxia-inducible factor-1 (HIF-1)-dependent EC-specific mechanism is an essential component of tumor angiogenesis. Recently, the Rho/Rho-associated kinase (ROCK) signaling has been shown to play a key role in HIF-1alpha induction in renal cell carcinoma and trophoblast. The present study was designed to investigate whether low oxygen conditions might modulate HIF-1alpha expression through the Rho/ROCK signaling in human umbilical vascular ECs (HUVEC). Pull-down assay showed that hypoxia stimulated RhoA activity. Under hypoxic conditions, HUVECs transfected with small interfering RNA of RhoA and ROCK2 exhibited decreased levels of HIF-1alpha protein compared with nontargeted small interfering RNA transfectants, whereas HIF-1alpha mRNA levels were not altered. One of ROCK inhibitors, fasudil, inhibited hypoxia-induced HIF-1alpha expression without altering HIF-1alpha mRNA expression. Furthermore, proteasome inhibitor prevented the effect of fasudil on HIF-1alpha expression, and polyubiquitination was enhanced by fasudil. These results suggested that hypoxia-induced HIF-1alpha expression is through preventing HIF-1alpha degradation by activating the Rho/ROCK signaling in ECs. Furthermore, hypoxia induced both vascular endothelial growth factor (VEGF) and VEGF receptor-2 expression through the Rho/ROCK/HIF-1alpha signaling in HUVECs. Thus, augmented VEGF/VEGF receptor-2 autocrine mechanism stimulated HUVEC migration under hypoxic conditions. In summary, the Rho/ROCK/HIF-1alpha signaling is an essential mechanism for hypoxia-driven, VEGF-mediated autocrine loop in ECs. Therefore, fasudil might have the antimigratory effect against ECs in tumor angiogenesis.