缺氧时培养的肺动脉平滑肌细胞血管紧张素Ⅱ自分泌的变化及其机制

缺氧是否通过影响血管平滑肌细胞的自分泌功能而参与缺氧性肺动脉高压的发生尚不清楚。本实验动态了缺氧对培养的新生小牛肺动脉平滑肌细胞（ＰＡＳＭＣｓ）的血管紧张素Ⅱ（ＡＴⅡ）分泌的影响。结果发现：２．５％Ｏ２缺氧导致ＰＡＳＭＣｓ的ＡＴⅡ分泌降低,０％Ｏ２缺氧进一步抑制ＡＴⅡ分泌。常氧条件下,ＮＯ供体ＳＩＮ－１显著的抑制ＡＴⅡ分泌,而ＮＯ合酶凶制剂硝基精氨酸（ＬＮＡ）则能消除缺氧对ＡＴⅡ分泌的抑制作用。０     

周期应变对动脉平滑肌细胞分泌血管紧张素II的影响

应用自行设计的硅胶膜伸张加载装置对培养硅胶膜上的Ｗｉｓｔａｒ大鼠主动脉平滑肌细胞施以周期性二维伸张应变,运用放射免疫沉淀法对其Ａｇ１１的分泌量进行测定,结果表明：加载组血管紧张素Ⅱ分泌量明显高于对照组,对照组分泌曲线较平坦,而加载组曲线较尖锐;加载４ｈ,ＡｇⅡ分泌量达到峰值。     

周期应变对动脉平滑肌细胞分泌血管紧张素II的影响

应用自行设计的硅胶膜伸张加载装置对培养于硅胶膜上的Ｗｉｓｔａｒ 大鼠主动脉平滑肌细胞施以周期性二维伸张应变（ 最大伸长比：纵向０ ．７ ％ ,横向０ ．３ ％ ） ,运用放射免疫沉淀法对其ＡｇＩＩ 的分泌量进行测定, 结果表明： 加载组血管紧张素ＩＩ 分泌量明显高于对照组（Ｐ＜ ０ ．００１ ,２ｈ ,１０ｈ 除外） ,对照组分泌曲线较平坦,而加载组曲线较尖锐;加载４ｈ ,ＡｇＩＩ分泌量达到峰值（２１９ ±２０ ．０ｐｇ／１０５ｃｅｌｌｓ） 。结合形态观察,表明力学信号能对主动脉平滑肌细胞的行为产生明显影响     

心房钠尿肽对血管紧张素Ⅱ促血管平滑肌细胞增殖和c-fos原癌基因表达的影响

本工作应用细胞培养、~3氢·胸腺嘧啶核苷参入和斑点杂交的方法,观察到血管紧张素Ⅱ(AGTⅡ)明显促进培养的自发性高血压大鼠的主动脉平滑肌细胞(VSMC)的增殖和c-fos原癌基因的表达;该效应可显著为心房钠尿肽(ANP)所抑制。     

黏着斑激酶与肿瘤微环境

黏着斑激酶（focal adhesion kinase, FAK）是一种胞质非受体酪氨酸激酶。FAK和肿瘤密切相关,在多种癌细胞中高表达,促进癌细胞的发生、生长、存活、增殖、粘附、转移和侵袭以及血管生成等过程。肿瘤微环境包括肿瘤细胞、周围血管、免疫细胞、纤维母细胞、内皮细胞、信号分子和细胞外基质,它对癌症的发展和恶化具有重要作用。肿瘤细胞可以通过分泌细胞外信号影响微环境,使其有利于肿瘤生存和发展|肿瘤微环境中的基质细胞能通过产生趋化因子、基质降解酶和生长因子促进肿瘤侵袭和转移。本文综述肿瘤微环境在癌症发生发展过程中的作用及FAK在肿瘤微环境中的调控作用,为肿瘤疾病的治疗提供新思路。     

血管紧张素Ⅱ上调自发性高血压大鼠和Wistar-Kyoto大鼠血管平滑肌细胞外信号调节激酶的信号转导

本文研究血管紧张素Ⅱ(angiotensin Ⅱ,Ang Ⅱ)对自发性高血压大鼠(spontaneously hypertensive rat,SHR)和Wistar- Kyoto(WKY)大鼠血管平滑肌细胞(vascular smooth muscle cells．VSMCs)细胞外信号调节激酶(extracellular signal-regulated pro- tein kinases,ERKs)信号途径的影响。体外培养SHR和WKY大鼠的VSMCs,先在培养基中加入终浓度为1×105mmol／L 的缬沙坦或1×105mmol／L的PD98059或不加药物,再给予1×107mmol／L的Ang Ⅱ刺激24 h后收集细胞,以无血清培养基 培养的VSMCs作对照。用免疫沉淀法测定ERK活性;用Western-blot方法检测总ERK(total ERK,t-ERK)、磷酸化ERK (phosphorylated-ERK,p-ERK)及丝裂素活化蛋白激酶磷酸酶-1(mitogen-activated protem kinases phosphatase-1,MKP-1)水 平;用RT-PCR法半定量测定MKP-1 mRNA的含量。结果显示:(1)SHR和WKY大鼠Ang Ⅱ刺激组VSMCs中ERK活 性、p-ERK、MKP-1及MKP-1 mRNA水平均明显高于对照组(P<0．05);SHR和WKY大鼠Ang Ⅱ+缬沙坦组和Ang Ⅱ +PD98059组的上述指标与对照组比较均无显著性差异。(2)SHR大鼠VSMCs中ERK活性、P-ERK、MKP-1及MKP-1 mRNA均显著高于相同干预的WKY大鼠(P<0．01)。(3)SHR和WKY大鼠之间以及对照组、Ang Ⅱ刺激组、Ang Ⅱ+缬沙 坦组和Ang Ⅱ+PD98059组间VSMCs中t-ERK水平均无显著性差异。以上结果表明,Ang Ⅱ可能主要通过其1型(Ang Ⅱ type 1,AT)受体激活SHR和WKY大鼠VSMCs中ERK途径,增加ERK活性和p-ERK蛋白水平,继而引起MKP-1及 MKP-1 mRNA水平升高。     

下调血管生成素样蛋白7表达对血管紧张素Ⅱ介导的血管平滑肌细胞炎症反应的影响

目的探讨RNA干扰血管生成素样蛋白7 （Angptl7）基因对血管紧张素Ⅱ（AngⅡ）诱导的血管平滑肌细胞（VSMC）炎症因子的影响及其作用机制。 方法体外培养人VSMC,分为常规F12K培养基培养（对照）和1 μg/mL AngII培养24 h。VSMC用AngⅡ（1 μg/mL）处理24 h后,采用siRNA-Angptl7和阴性对照siRNA-NC在Lipofectamine 2000介导下转染VSMC。RT-qPCR检测mRNA表达水平;Griess反应测定一氧化氮（NO）含量;蛋白免疫印记法检测相关蛋白的改变;酶联免疫吸附法检测VSMC中炎症因子肿瘤坏死因子α（TNF-α）、白细胞介素-1β （IL-1β）和IL-6水平。多组间比较采用单因素方差分析,组间两两比较采用LSD-t检验,两组间比较采用独立样本t检验。 结果与对照比较,1 μg/mL AngⅡ处理可促进VSMC中Angptl7 mRNA （0.97±0.06比3.05±0.21）和蛋白表达（1.01±0.12比1.61±0.14）,亦可促进VSMC中IL-1β[（45.21±8.10）比（126.17±11.77） pg/mL]、IL-6[（50.50±7.51）比（108.50±9.51）pg/mL]和TNF-α的表达[（60.77±9.58）比（185.67±17.35）pg/mL],差异有统计学意义（P均< 0.01）。与对照和转染siRNA-NC相比,转染siRNA-Angptl7下调Angptl7蛋白表达（0.99±0.12,0.98±0.12比0.44±0.14,P < 0.01）。与AngⅡ干预组相比,siRNA-Angptl7降低AngⅡ介导的VSMC炎症反应相关蛋白TNF-α、IL-6和IL-1β的表达,核因子κB （NF-κB）/诱导型一氧化氮合酶（iNOS）/环氧化酶2 （COX-2）信号通路相关蛋白NF-κB、iNOS和COX-2表达及NO含量亦降低,差异有统计学意义（P均< 0.01）。与siRNA-NC相比,siRNA-Angptl7组AngⅡ诱导的VSMC炎症反应相关蛋白TNF-α （0.99±0.13比0.51±0.12）、IL-6 （1.00±0.12比0.38±0.05）和IL-1β的表达（0.99±0.14比0.48±0.11）,NF-κB （1.00±0.10比0.42±0.08）、iNOS （1.02±0.12比0.42±0.10）和COX-2表达（1.00±0.11比0.52±0.12）均降低,NO含量[（54.78±2.76）比（18.08±3.61）μmol/L]亦降低,差异有统计学意义（P均< 0.01）。 结论AngⅡ可通过Angptl7促进VSMC炎症反应,下调Angptl7蛋白表达可以抑制VSMC的炎症反应,其作用机制可能与抑制NF-κB/iNOS-COX-2信号通路有关。     

KLF5与c-Jun相互作用促进Ang II诱导的血管平滑肌细胞增殖

KLF5（Krüppel-like factor 5）是KLF家族转录因子中的成员,参与多种与增 殖相关基因的转录调节.通过体外培养大鼠血管平滑肌细胞（vascular smooth muscle cells, VSMC）,以Ang Ⅱ为增殖诱导因素,研究KLF5介导VSMC增殖的机制. 研究发现,Ang Ⅱ可剂量依赖性诱导VSMC增殖,并伴有KLF5和c-Jun蛋白表达水平的 升高.为了证实KLF5参与Ang Ⅱ诱导的细胞增殖过程,用siRNA敲低内源性KLF5的表达后,发现细胞增殖活力受到明显的抑制;交互免疫沉淀和GST pull down分析结果显示,KLF5与c-Jun在体内和体外存在物理学上的相互作用,并且Ang Ⅱ可诱导二者之间的相互缔合.这些结果表明,KLF5通过与c-Jun相互作用进而介导Ang Ⅱ诱导的VSMC 增殖.     

低氧、血管紧张素Ⅱ对肺内小动脉平滑肌细胞膜Ca2 ┐ATPase活力的影响

本课题观察了低氧及血管紧张素Ⅱ（ａｎｇｉｏｔｅｎｓｉｎⅡ,ＡｎｇⅡ）对分离培养家兔肺内小动脉平滑肌细胞（ＰＡＳＭ－Ｃｓ）膜Ｃａ２＋－ＡＴＰａｓｅ活力的影响,同时用钙通道阻断剂维拉帕米（ｖｅｒａｐａｍｉｌ,ＶＰ）进行干预,进一步了解细胞内钙与Ｃａ２＋－ＡＴＰａｓｅ活力的关系。结果表明：ＰＡＳＭＣｓ膜Ｃａ２＋－ＡＴＰａｓｅ活力对低氧具有短暂的耐受性,随低氧时间延长,Ｃａ２＋－ＡＴＰａｓｅ活力呈时间依赖性抑制;低氧、ＡＮＧⅡ均能抑制Ｃａ２＋－ＡＴＰａｓｅ活力（Ｐ＜０．０１）低氧＋ＡⅡ对Ｃａ２＋－ＡＴＰａｓｅ活力的抑制具叠加效应（Ｐ＜０．０５）;ＶＰ可逆转低氧、ＡｎｇⅡ、低氧＋ＡｎｇⅡ对Ｃａ２＋－ＡＴＰａｓｅ活力的抑制（Ｐ＜０．０１）。结果提示：低氧,ＡＮＧⅡ可通过抑制肺血管平滑肌细胞膜Ｃａ２＋－ＡＴＰａｓｅ活力而可能削弱肺血管平滑肌舒张功能也可能是低氧性肺动脉高压（ＨＰＨ）形成的原因之一。     

血管紧张素Ⅱ对肾上腺糖皮质激素分泌的影响

本工作观察了血管紧张素Ⅱ（ＡⅡ）对豚鼠和狗的肾上组织皮质醇分泌量的影响。结果表明,当ＡⅡ浓度≥１０＾－９ｍｏｌ／Ｌ时孵育液中皮质醇含量显著增加（Ｐ〈０．０１）,并且具有较明显的量效关系和时效关系。ＡⅡ以及促肾上腺皮质激素（ＡＣＴＨ）与肾上腺组织或细胞一同孵育时,皮质醇的分泌量明显高于ＡⅡ和ＡＣＴＨ单独存在时的分泌量（Ｐ〈０．０５）。孵育液内游离钙减少时ＡⅡ促皮质醇分泌的作用有所降低（Ｐ〈０．０５）     

青心酮对体外培养的HPASMCs合成、分泌FAK和caspase-3的影响

目的:研究青心酮(3.4-DHAP)对人肺血管平滑肌细胞(HPASMCs)的作用。方法:应用免疫印迹、免疫组织化学等方法测定了黏着斑激酶(FAK)、半胱氨酸蛋白酶(caspase-3)的蛋白质表达。结果:应用青心酮后FAK蛋白的表达量明显减少,胞浆蛋白caspase-3表达明显增高。结论:青心酮影响体外培养的HPASMCs的FAK、caspase-3合成及分泌。     

Hypertrophic response to angiotensin II is mediated by protein kinase D-extracellular signal-regulated kinase 5 pathway in human aortic smooth muscle cells

Angiotensin II plays a critical role in hypertrophy of vascular smooth muscle cells, however, the molecular underpinnings remain unclear. The present study indicated that AT₁/PKC/PKD pathway was able to regulate downstream ERK5, affecting pro-hypertrophic responses to Ang II. Ang II-stimulated phosphorylation of ERK5 in a time- and dose-dependent manner in human aortic smooth muscle cells (HASMCs). The pharmacological inhibitors for AT₁ and PKCs significantly inhibited Ang II-induced ERK5 activation, suggesting the involvement of the AT₁/PKC pathway. In particular, PKD was critical for Ang II-induced ERK5 activation since silencing PKD by siRNA markedly inhibited Ang II-induced ERK5 activation. Consequently, we found that Losartan, Gö 6983 and PKD siRNA significantly attenuated ERK5 activated translocation and hypertrophy of HASMCs by Ang II. Taken together, we demonstrated for the first time that Ang II activates ERK5 via the AT₁/PKC/PKD pathway and revealed a critical role of ERK5 in Ang II-induced HASMCs hypertrophy.     

尾加压素增加血管平滑肌细胞粘着斑激酶的含量和活力

在体外培养的血管平滑肌细胞上,采用蛋白印迹杂交免疫沉淀的方法,研究尾加压素Ⅱ（ＵⅡ）与粘着斑激酶（ＦＡＫ）介导的信号传导之间的关系。结果表明,ＵⅡ在１０＾－８、１０＾－７和１０＾－６ｍｏｌ／Ｌ的深度时,可分别使ＦＡＫ活力增加２．２、３．０４和０．７３倍。加入ＵⅡ在（１０＾０７ｍｏｌ／Ｌ）５ｍｉｎ后,ＦＡＫ活力增加９５％,但与对照组相比无显著性差异（Ｐ〉０．０５０,刺激１０ｍｉｎ后,ＦＡＫ活力升高３     

The functional expression of extracellular calcium-sensing receptor in rat pulmonary artery smooth muscle cells

Background

The extracellular calcium-sensing receptor (CaSR) belongs to family C of the G protein coupled receptors. Whether the CaSR is expressed in the pulmonary artery (PA) is unknown.

Methods

The expression and distribution of CaSR were detected by RT-PCR, Western blotting and immunofluorescence. PA tension was detected by the pulmonary arterial ring technique, and the intracellular calcium concentration ([Ca²⁺]_i) was detected by a laser-scanning confocal microscope.

Results

The expressions of CaSR mRNA and protein were found in both rat pulmonary artery smooth muscle cells (PASMCs) and PAs. Increased levels of [Ca²⁺]_o (extracellular calcium concentration) or Gd³⁺ (an agonist of CaSR) induced an increase of [Ca²⁺]_i and PAs constriction in a concentration-dependent manner_. In addition, the above-mentioned effects of Ca²⁺ and Gd³⁺ were inhibited by {"type":"entrez-nucleotide","attrs":{"text":"U73122","term_id":"4098075","term_text":"U73122"}}U73122 (specific inhibitor of PLC), 2-APB (specific antagonist of IP₃ receptor), and thapsigargin (blocker of sarcoplasmic reticulum calcium ATPase).

Conclusions

CaSR is expressed in rat PASMCs, and is involved in regulation of PA tension by increasing [Ca²⁺]_i through G-PLC-IP₃ pathway.     

Pleiotropic effects of statins in distal human pulmonary artery smooth muscle cells

Background

Recent clinical data suggest statins have transient but significant effects in patients with pulmonary arterial hypertension. In this study we explored the molecular effects of statins on distal human pulmonary artery smooth muscle cells (PASMCs) and their relevance to proliferation and apoptosis in pulmonary arterial hypertension.

Methods

Primary distal human PASMCs from patients and controls were treated with lipophilic (simvastatin, atorvastatin, mevastatin and fluvastatin), lipophobic (pravastatin) and nitric-oxide releasing statins and studied in terms of their DNA synthesis, proliferation, apoptosis, matrix metalloproteinase-9 and endothelin-1 release.

Results

Treatment of human PASMCs with selected statins inhibited DNA synthesis, proliferation and matrix metalloproteinase-9 production in a concentration-dependent manner. Statins differed in their effectiveness, the rank order of anti-mitogenic potency being simvastatin > atorvastatin > > pravastatin. Nevertheless, a novel nitric oxide-releasing derivative of pravastatin (NCX 6550) was effective. Lipophilic statins, such as simvastatin, also enhanced the anti-proliferative effects of iloprost and sildenafil, promoted apoptosis and inhibited the release of the mitogen and survival factor endothelin-1. These effects were reversed by mevalonate and the isoprenoid intermediate geranylgeranylpyrophosphate and were mimicked by inhibitors of the Rho and Rho-kinase.

Conclusions

Lipophilic statins exert direct effects on distal human PASMCs and are likely to involve inhibition of Rho GTPase signalling. These findings compliment some of the recently documented effects in patients with pulmonary arterial hypertension.