AQP1促进肺动脉平滑肌细胞的增殖与迁移（应作者要求撤稿）

该文应作者要求已撤稿。肺动脉平滑肌细胞（PASMCs）的迁移和增殖是肺动脉重塑进而造成肺动脉高压的主要病理基础。水通道蛋白1（AQP1）具有促进上皮细胞、内皮细胞迁移的作用,但机制不清。由于AQP1也表达于血管平滑肌细胞,推测AQP1可能参与缺氧诱导的PASMCs增殖及迁移。通过PCR和免疫印迹分析,检测AQP的表达以及缺氧对AQP表达水平的影响,并通过细胞迁移以及增殖实验观察AQP1在缺氧诱导的PASMCs迁移与增殖中的作用。AQP1在PASMCs和主动脉平滑肌细胞（AoSMCs）均表达,但缺氧只增加PASMCs中AQP1的表达,以及促进PASMCs的迁移与增殖。敲除AQP1可抑制PASMCs的增殖以及缺氧诱导的细胞增殖和迁移。过表达AQP1促进PASMCs的增殖和迁移。缺氧促进β联蛋白在PASMCs内的表达。敲除β联蛋白后,抑制AdAQP1所介导的PASMCs迁移与增殖。这些结果表明,缺氧可促进AQP1在肺动脉内的表达,AQP1可通过β联蛋白对PASMCs的增殖和迁移进行调节。     

时钟基因Bmal1促进血管平滑肌细胞增殖

摘要 目的：观察时钟基因Bmal1的过表达对血管平滑肌细胞增殖的影响,进一步探讨生物节律对于血管发育的具体影响。方法：采用包装GV341-Bmal1载体的慢病毒转染的方法构建大鼠胸主动脉平滑肌细胞（A7R5）稳定转染Bmal1的细胞系,实时定量PCR和细胞爬片Bmal1的免疫荧光染色的方法判断所构建细胞系是否稳定过表达Bmal1,细胞爬片Ki67的免疫荧光染色的方法观察时钟基因Bmal1的过表达对血管平滑肌细胞增殖的影响。结果：实时定量PCR结果显示稳定转染Bmal1组细胞Bmal1的表达是对照组的11.2倍（P<0.01）;细胞爬片的免疫荧光染色结果显示稳定转染Bmal1组细胞BMAL1的表达明显升高（P<0.05）,且稳定转染Bmal1组Ki67阳性细胞比例明显升高（P<0.05）。结论：通过慢病毒转染的方法成功构建了血管平滑肌细胞稳定转染Bmal1的细胞系,细胞片Ki67的免疫荧光染色结果显示Bmal1的过表达促进了血管平滑肌细胞的增殖。     

miR-20a靶向CCND1作用PI3K/AKT信号通路抑制皮肤鳞状细胞癌的发展

摘要 目的：探究miR-20a与CCND1蛋白在皮肤鳞状细胞癌（CSCC）中的作用关系,以及其可能涉及的信号通路分子机制。方法：分别收集皮肤鳞状细胞癌患者的皮肤癌组织及其邻近正常皮肤组织,采用qRT-PCR分析组织中miR-20a和CCND1基因表达水平。为探究miR-20a对CSCC细胞的影响,将SCL-1细胞分为对照组（不转染）、miR-NC组（转染miR-NC）和miR-20a mimics组（转染miR-20a mimics）;为探究CCND1与PI3K/AKT信号通路的关系,将SCL-1细胞分为对照组（不转染）、si-NC组（转染si-NC）和si-CCND1组（转染si-CCND1）;为探究miR-20a与CCND1间的作用关系及对CSCC细胞的影响,将SCL-1细胞分为miR-NC组（转染miR-NC）、miR-20a mimics组（转染miR-20a mimics）、mimics+pcDNA组（共转染miR-20a mimics和pcDNA）和mimics+CCND1组（共转染miR-20a mimics和pcDNA-CCND1）。采用Western blot分析p-AKT、AKT、p-PI3K、PI3K和GSK-3β蛋白表达水平;采用MTT检测细胞增殖情况;采用流式细胞术检测细胞凋亡情况;采用Transwell分析细胞迁移和侵袭情况;采用双荧光素酶报告基因检测分析miR-20a与CCND1的靶向关系。结果：CSCC癌组织和SCL-1中miR-20a均低表达,CCND1高表达。与对照组和miR-NC组比较,miR-20a mimics组SCL-1细胞增殖水平以及侵袭和迁移数量均降低（P<0.05）,SCL-1细胞凋亡水平升高（P<0.05）,PI3K和AKT蛋白磷酸化水平降低（P<0.05）。TargetScanHuman数据库分析和双荧光素酶报告基因检测结果显示miR-20a与CCND1存在靶向作用关系。与对照组和si-NC组比较,si-CCND1组SCL-1细胞中CCND1和GSK-3β蛋白表达水平以及PI3K和AKT蛋白磷酸化水平均降低（P<0.01）。与miR-20a mimics组或mimics+pcDNA组比较,mimics+CCND1组SCL-1细胞增殖水平以及侵袭和迁移数量均升高（P<0.05）,SCL-1细胞凋亡水平降低（P<0.05）,PI3K和AKT蛋白磷酸化水平均升高（P<0.05）。结论：过表达miR-20a可能通过靶向抑制CCND1的表达而抑制PI3K/AKT信号通路的激活,从而抑制CSCC细胞的增殖、侵袭和迁移,并促进癌细胞凋亡。     

自噬抑制剂氯奎对低氧诱导肺动脉平滑肌细胞增殖的影响

目的：探讨自噬抑制刺氯喹（cQ）在低氧（hypoxia）调节肺动脉平滑肌细胞（PASMCs）增殖中的作用。方法：将体外培养的大鼠PASMCs分为4组：正常对照组、1％低氧组、50μmol／L氯喹＋1％低氧组、50ttmol／L氯喹组。MTF方法检测各组的PASMCs增殖率;MDC染色检测细胞自噬空泡的变化;Westernblot方法检测微管相关蛋白轻链3（LC3）蛋白的表达变化;划痕法检测细胞迁移的变化。结果：与对照组比较,氯喹组的PASMCs细胞增殖率无明显变化。与对照组比较,1％低氧组PASMCs增殖率明显增加,细胞内出现大量自噬空泡,细胞迁移速度明显增加。细胞LC3-Ⅱ蛋白表达增强。与1％低氧组比较,氯喹与低氧联合作用时细胞自噬空泡的积聚以及rE3．II蛋白表达增强,但细胞增殖率和迁移明显降低。结论：低氧激活自噬过程并促进了PASMCs增殖和迁移,而自噬抑制剂氯喹在一定程度上通过抑制自噬进程,达到抑制肺动脉平滑肌细胞增殖和迁移的作用。     

脂联素抑制子宫内膜癌HEC-1B细胞增殖、迁移及侵袭的作用及机制研究

摘要 目的：探讨脂联素（APN）对子宫内膜癌HEC-1B细胞增殖、迁移及侵袭的抑制作用及分子机制。方法：分别采用磺酰罗丹明 B(SRB)实验、细胞迁移(Transwell)实验和划痕实验检测子宫内膜癌细胞HEC-1B的增殖、迁移和侵袭能力。采用蛋白免疫印迹（Western blot）法检测腺苷酸活化蛋白激酶(AMPK)信号通路相关蛋白、AdipoR1、AdipoR2、cyclinD1和cyclinE2蛋白表达水平。结果：与对照组相比,APN组HEC-1B细胞增殖、迁移及侵袭功能明显下降（P<0.05）。与对照组相比,APN组p-AMPK/AMPK比值明显提高,而p-mTOR/mTOR和p-4EBP1/4EBP1比值明显下降（P<0.05）。与对照组相比,APN组cyclinD1和cyclinE2蛋白表达水平明显下降（P<0.05）。APN组和对照组的AdipoR1、AdipoR2蛋白表达水平比较无统计学差异（P>0.05）。结论：APN能够激活AMPK信号通路并下调cyclinD1和cyclinE2蛋白表达,进而抑制子宫内膜癌细胞的增殖、迁移和侵袭功能。     

车前草提取物对缺氧性肺动脉高压SD大鼠模型肺动脉压力、肺功能及炎症因子的影响

摘要 目的：探讨车前草提取物对缺氧性肺动脉高压(HPH)SD大鼠模型肺动脉压力、肺功能及炎症改变的效果。方法：随机选取18只SD雄性大鼠分为3组,正常对照组（Control组）、缺氧性肺动脉高压（HPH组）、车前草干预组（PW组）,每组各6只。观察并记录各组大鼠日常状况,于第21天测定大鼠肺动脉压力、肺功能后处死各组6只大鼠,获取大鼠肺组织标本,左肺泡灌洗液予Elisa试剂盒检测各组ICAM-1、TGF-β、MMP-9因子含量,右肺上中下叶各取一块组织行苏木精-伊红染色,其余肺组织研磨匀浆后予Elisa试剂盒检测HIF-1α含量。结果：用PW干预HPH大鼠,可降低SD大鼠的平均肺动脉压力,提高0.4 sFEV、FVC、0.4sFEV/FVC、MMEF等肺功能指标,降低肺泡灌洗液中ICAM-1、TGF-β、MMP-9炎症因子水平及肺组织中HIF-1a水平,气道及肺动脉管腔扩大,管壁变薄,炎性细胞浸润减少。结论：车前草提取物能降低HIF-1a水平,减轻HPH SD大鼠的炎症反应,降低肺动脉压力,提升肺功能,改善肺动脉及气道重塑。     

血浆M-CSF、MMP9、TIMP-1水平及HPV阳性大鼠宫颈癌增殖能力的关系研究

摘要 目的：探究血浆巨噬细胞集落刺激因子（Macrophage colony stimulating factor, M-CSF）、基质金属蛋白酶9（Matrix metalloproteinase 9, MMP9）及其组织抑制因子1（tissue inhibitor of the metalloproteinases, TIMP1）水平及人乳头瘤病毒（Human papilloma virus,HPV）阳性大鼠宫颈癌增殖能力的关系。方法：20只健康雌性Wistar白化大鼠根据实验目的分为两组：对照组（异种移植时注射SiHa细胞作为对照实验,n=10）和观察组（将转染sh-M-CSF、sh-MMP9和sh-TIMP-1的SiHa细胞注射大鼠的子宫颈,n=10）。通过ELISA测定大鼠血浆M-CSF、MMP9和TIMP-1的水平。通过PCR检测实验大鼠中M-CSF、MMP9和TIMP-1的mRNA表达。使用数字游标卡尺分析大异种移植大鼠肿瘤体积生长。第3、4、5周分别处死并切除大鼠肿瘤进行称重。通过免疫组织化学分析肿瘤组织中增殖细胞核抗原（Proliferating cell nuclear antigen,PCNA）、pAKT和pSTAT3的蛋白表达。通过免疫组织化学染色和TUNEL染色分别确定Ki67阳性细胞数量及凋亡细胞数量。结果：观察组较对照组M-CSF、MMP9和TIMP-1的水平降低（P<0.05）。观察组较对照组M-CSF、MMP9和TIMP-1的mRNA表达降低（P<0.05）。随着时间的增加,两组大鼠肿瘤体积均增加。1周和2周对照组和观察组大鼠肿瘤体积比较无差异（P>0.05）,第3周、第4周和第5周,观察组较对照组大鼠肿瘤体积降低（P<0.05）。观察组较对照组大鼠体内肿瘤重量减少（P<0.05）。观察组较对照组PCNA、pAKT和pSTAT3的蛋白表达量降低（P<0.05）。观察组较对照组Ki67 阳性细胞数量降低,凋亡细胞升高（P<0.05）。结论：降低血浆M-CSF、MMP2和TIMP1水平可促进HPV阳性大鼠宫颈癌细胞凋亡,有效抑制细胞增殖。     

CXCR4 抑制剂AMD3100 对大鼠低氧性肺动脉高压作用的实验研究

目的:研究CXC趋化因子受体-4(CXC Chemokine receptor-4,CXCR4)的抑制剂(AMD3100)对大鼠低氧性肺动脉高压的影响。方法:将实验动物随机分为常氧对照组、低氧组、低氧+AMD3100组,采用低压低氧法建立大鼠低氧性肺动脉高压模型,4周后观察低氧对CXCR4表达的影响及各组大鼠血流动力学、右心室肥厚指标和组织病理学改变。培养原代大鼠肺动脉平滑肌细胞(Pulmonary arterial smooth cells,PASMCs),分别低氧处理及给予AMD3100,观察细胞迁移、增殖情况。结果:1低氧组大鼠CXCR4表达增加,右心室压力(Mean right ventricle pressure,m RVP)、右心室肥厚指标(Right ventricle/Body weight,RV/BW;Right ventricle/Left ventricle plus septum,RV/(LV+S))增加,肺细小动脉管壁增厚,造模成功;低氧+AMD3100组大鼠m RVP和RV/BW、RV/(LV+S)比值、肺细小动脉管壁增厚程度较低氧组明显降低(P0.05)。2低氧组PASMCs与常氧组相比,细胞迁移及增殖均明显增加;AMD3100组PASMCs迁移和增殖与低氧组相比受抑制(P0.05)。结论:AMD3100能有效的降低大鼠低氧性肺动脉高压的m RVP,抑制肺细小动脉管壁的增生,减轻右心室的肥厚,其有可能是通过抑制了PASMCs的迁移和增殖,从而抑制肺血管的重建,防治低氧性肺动脉高压。     

RNA干扰沉默低氧诱导因子-1α对低氧下大鼠肺动脉平滑肌细胞增殖的影响

本研究应用基因克隆技术,将合成的发卡样特异性低氧诱导因子-1α（hypoxia inducible factor-1alpha,HIF-1α）干扰寡核苷酸（siRNA）序列插入真核表达载体中,构建出特异性HIF-1α基因RNA干扰（RNAi）真核表达载体。采用组织块种植法,原代培养大鼠肺动脉平滑肌细胞（pulmonary artery smooth muscle cells,PASMCs）,将构建出的特异性HIF-1αRNAi真核表达载体转染到PASMCs;分别在常氧和低氧下进行细胞培养,采用RT-PCR检测PASMCsHIF-1αmRNA表达水平,用MTT和流式细胞仪检测细胞增殖水平,探讨低氧条件下HIF-1αRNAi真核表达载体对PASMCs增殖的影响。结果表明,低氧培养48h后,正常PASMCs和转染了HIF-1αsiRNA阴性表达载体的细胞增殖显著,HIF-1αmRNA表达水平也显著升高;而转染了HIF-1αsiRNA阳性表达质粒的细胞增殖不显著,HIF-1αmRNA表达水平较低。结果提示：HIF-1αRNAi真核表达载体能显著干扰培养的PASMCsHIF-1αmRNA表达,同时抑制低氧环境下PASMCs的增殖。     

MicroRNA-520e通过靶向抑制AEG-1发挥抗结直肠癌特性

摘要 目的：探究MicroRNA-520e（miR-520e）在结直肠癌中的表达模式及其对细胞功能的影响。方法：采用qRT-PCR方法检测47例结直肠癌患者的癌组织和癌旁组织中miR-520e和星形胶质细胞上调基因-1（AEG-1）的mRNA表达水平。将SW480细胞分为对照组、miR-520e-mimic组、NC-mimic组、miR-520e-inhibitor组、NC-inhibitor组、miR-520e-mimic+AEG-1-pcDNA3.1组和miR-520e-mimic+NC-pcDNA3.1组。通过MTT法检测SW480细胞的增殖,通过Annexin V-FITC/PI双染色试剂盒检测细胞凋亡,通过Transwell检测细胞迁移和侵袭,通过双荧光素酶报告基因实验验证miR-520e和AEG-1的靶向关系,通过qRT-PCR或Western blotting检测AEG-1、基质金属蛋白酶2（MMP2）、MMP9、NF-κB p65（p65）和磷酸化的NF-κB p65（p-p65）的表达。结果：与癌旁组织相比,结直肠癌组织中miR-520e的表达水平降低（t=9.353,P<0.001）。与对照组相比,miR-520e-mimic组的OD_490nm 值降低,细胞凋亡率升高,细胞迁移和侵袭数量降低,MMP2、MMP9和p-p65蛋白表达水平降低（P<0.001）。与对照组相比,miR-520e-inhibitor组的OD_490nm 值升高,细胞凋亡率降低,细胞迁移和侵袭数量升高,MMP2、MMP9和p-p65蛋白表达水平升高。与NC-mimic组相比,miR-520e-inhibitor组的相对荧光素酶活性降低（P<0.001）。与对照组相比,miR-520e-mimic组的AEG-1的mRNA和蛋白表达水平均降低,而miR-520e-inhibitor组均升高（P<0.001）。与miR-520e-mimic+NC-pcDNA3.1组相比,miR-520e-mimic+AEG-1-pcDNA3.1组的AEG-1的mRNA和蛋白表达水平升高,OD_490nm 值升高,细胞凋亡率降低,迁移和侵袭细胞数增加,MMP2和MMP9的蛋白表达水平及p65的磷酸化水平均增加（P<0.001）。结论：miR-520e在结直肠癌中表达降低,可通过靶向抑制AEG-1来发挥抗结直肠癌特性,其抗癌机制可能通过NF-κB信号通路介导。     

ERK/Drp1‐dependent mitochondrial fission contributes to HMGB1‐induced autophagy in pulmonary arterial hypertension

ObjectivesHigh‐mobility group box‐1 (HMGB1) and aberrant mitochondrial fission mediated by excessive activation of GTPase dynamin‐related protein 1 (Drp1) have been found to be elevated in patients with pulmonary arterial hypertension (PAH) and critically implicated in PAH pathogenesis. However, it remains unknown whether Drp1‐mediated mitochondrial fission and which downstream targets of mitochondrial fission mediate HMGB1‐induced pulmonary arterial smooth muscle cells (PASMCs) proliferation and migration leading to vascular remodelling in PAH. This study aims to address these issues.MethodsPrimary cultured PASMCs were obtained from male Sprague‐Dawley (SD) rats. We detected RNA levels by qRT‐PCR, protein levels by Western blotting, cell proliferation by Cell Counting Kit‐8 (CCK‐8) and EdU incorporation assays, migration by wound healing and transwell assays. SD rats were injected with monocrotaline (MCT) to establish PAH. Hemodynamic parameters were measured by closed‐chest right heart catheterization.ResultsHMGB1 increased Drp1 phosphorylation and Drp1‐dependent mitochondrial fragmentation through extracellular signal‐regulated kinases 1/2 (ERK1/2) signalling activation, and subsequently triggered autophagy activation, which further led to bone morphogenetic protein receptor 2 (BMPR2) lysosomal degradation and inhibitor of DNA binding 1 (Id1) downregulation, and eventually promoted PASMCs proliferation/migration. Inhibition of ERK1/2 cascade, knockdown of Drp1 or suppression of autophagy restored HMGB1‐induced reductions of BMPR2 and Id1, and diminished HMGB1‐induced PASMCs proliferation/migration. In addition, pharmacological inhibition of HMGB1 by glycyrrhizin, suppression of mitochondrial fission by Mdivi‐1 or blockage of autophagy by chloroquine prevented PAH development in MCT‐induced rats PAH model.ConclusionsHMGB1 promotes PASMCs proliferation/migration and pulmonary vascular remodelling by activating ERK1/2/Drp1/Autophagy/BMPR2/Id1 axis, suggesting that this cascade might be a potential novel target for management of PAH.     

Propylthiouracil Attenuates Experimental Pulmonary Hypertension via Suppression of Pen-2, a Key Component of Gamma-Secretase

Gamma-secretase-mediated Notch3 signaling is involved in smooth muscle cell (SMC) hyper-activity and proliferation leading to pulmonary arterial hypertension (PAH). In addition, Propylthiouracil (PTU), beyond its anti-thyroid action, has suppressive effects on atherosclerosis and PAH. Here, we investigated the possible involvement of gamma-secretase-mediated Notch3 signaling in PTU-inhibited PAH. In rats with monocrotaline-induced PAH, PTU therapy improved pulmonary arterial hypertrophy and hemodynamics. In vitro, treatment of PASMCs from monocrotaline-treated rats with PTU inhibited their proliferation and migration. Immunocyto, histochemistry, and western blot showed that PTU treatment attenuated the activation of Notch3 signaling in PASMCs from monocrotaline-treated rats, which was mediated via inhibition of gamma-secretase expression especially its presenilin enhancer 2 (Pen-2) subunit. Furthermore, over-expression of Pen-2 in PASMCs from control rats increased the capacity of migration, whereas knockdown of Pen-2 with its respective siRNA in PASMCs from monocrotaline-treated rats had an opposite effect. Transfection of PASMCs from monocrotaline-treated rats with Pen-2 siRNA blocked the inhibitory effect of PTU on PASMC proliferation and migration, reflecting the crucial role of Pen-2 in PTU effect. We present a novel cell-signaling paradigm in which overexpression of Pen-2 is essential for experimental pulmonary arterial hypertension to promote motility and growth of smooth muscle cells. Propylthiouracil attenuates experimental PAH via suppression of the gamma-secretase-mediated Notch3 signaling especially its presenilin enhancer 2 (Pen-2) subunit. These findings provide a deep insight into the pathogenesis of PAH and a novel therapeutic strategy.     

Role of platelet-derived growth factor-BB (PDGF-BB) in human pulmonary artery smooth muscle cell proliferation

Abstract

Pulmonary arterial hypertension (PAH) is a vascular remodeling disease characterized by enhanced proliferation of pulmonary artery smooth muscle cells (PASMCs) and suppressed apoptosis. Platelet-derived growth factor (PDGF) is a potent mitogen involved in cell proliferation and migration. PDGF-BB induces the proliferation and migration of PASMCs and has been proposed to be a key mediator in the progression of PAH. Previous studies have shown that PDGF and its receptor are substantially elevated in lung tissues and PASMCs isolated from patients and animals with PAH, but the underlying mechanisms are still poorly manifested. MAP kinases, including extracellular signal-regulated kinase1/2 (ERK1/2), c-Jun NH2-terminal kinase1/2 (JNK1/2), and p38 are the key intracellular signals for stimuli-induced cell proliferation, survival, and apoptosis. Therefore, the purpose of this study is to determine whether PDGF-BB on cell proliferation process is mediated through the MAP kinases pathway in human PASMCs (HPASMCs). Our results showed PDGF-BB-induced proliferating cell nuclear antigen (PCNA), Cyclin A and Cyclin E expression in a concentration-dependent manner. The expression levels of phosphorylated JNK (p-JNK) was upregulated with 20?ng/ml PDGF-BB treatment, while PDGF-BB could not increase phosphorylated ERK1/2 (p-ERK1/2) and p-38 (p-p38) expression. The effects of PDGF-BB on cell proliferation and survival were weakened after the administration of antagonist of the JNK pathway or si-JNK. In addition, PDGF-BB protected against the loss of mitochondrial membrane potentials evoked by serum deprivation (SD) in a JNK-dependent manner. These results suggest that PDGF-BB promotes HPASMCs proliferation and survival, which is likely to be mediated via the JNK pathway.     

Activation of PPAR-γ ameliorates pulmonary arterial hypertension via inducing heme oxygenase-1 and p21: An in vivo study in rats

Aims

Our previous study has indicated that activation of PPAR-γ inhibits the proliferation of rat pulmonary artery smooth muscle cells (PASMCs) in vitro through inducing the expression of heme oxygenase-1 (HO-1), which in turn up-regulates the p21^WAF1 expression. In the present study, we intended to determine whether similar mechanisms have been involved in activation of PPAR-γ inhibition of development of rat PAH model.

Material and methods

Rat pulmonary arterial hypertension (PAH) model was established by subcutaneous injection of monocrotaline (MCT). Rosiglitazone was administered to activate PPAR-γ. Zinc protoporphyria IX (ZnPP-IX), was used to confirm the role of HO-1 in mediating PPAR-γ function. Parameters including the right ventricle systolic pressure (RVSP), the right ventricular hypertrophy (RVH) and the percentage of medial wall thickness were used to evaluate the development of PAH. Immunoblotting was used to determine the expression of HO-1 and p21^WAF1.

Key findings

Rosiglitazone significantly decreased the RVSP and inhibited the RVH in MCT-induced rat PAH model, and partially inhibited the pulmonary vascular remodeling. These effects were coupled with the sequential increase of HO-1 and p21^WAF1 expressions by rosiglitazone.

Significance

Activation of PPAR-γ benefits PAH by inhibiting proliferation of PASMCs and reducing pulmonary vascular remodeling. The present study suggests that enhancing PPAR-γ activity might have potential value in clinical treatment of PAH.     

Norepinephrine stimulation of alpha1D-adrenoceptor promotes proliferation of pulmonary artery smooth muscle cells via ERK-1/2 signaling

It has been shown that the sympathetic nervous system is activated in pulmonary arterial hypertension (PAH). Norepinephrine (NE) levels are increased by chemoreflex-dependent sympathetic overactivation and involved in pulmonary vascular remodeling. However, the underlying mechanisms of the remodeling induced by NE are poorly understood. In this study, we found that, in vivo, the expression of tyrosine hydroxylase and the concentration of plasma NE were increased in PAH rats compared with normal rats. Increases in ventricular hypertrophy and medial width of the pulmonary arteries were reversed by prazosin, α₁-adrenoceptor (α₁-AR) antagonists, in PAH rats. Elevated expression of α_1D-AR was detected in PAH rats. In addition, prazosin reduced the increasing expression of PCNA, CyclinA and CyclinE induced by hypoxia. In vitro, MTT assay, flow cytometry, Western blotting and immunofluorescence were performed to investigate the effects of NE on proliferation of pulmonary artery smooth muscle cells (PASMCs). We revealed that NE promoted PASMCs viability, increased the expression of PCNA, CyclinA and CyclinE, made more cells from G₀/G₁ phase to G₂/M + S phase and enhanced the microtubule formation. Above NE-induced changes could be suppressed by BMY 7378, an inhibitor of α_1D-AR. Furthermore, ERK-1/2 pathway was activated by NE. U0126, a specific inhibitor for ERK-1/2, attenuated the NE-induced proliferation of PASMCs under normoxia and hypoxia. Taken together, our results suggest that NE which stimulates α_1D-AR promotes proliferation of PASMCs and the effect is, at least in part, mediated via the ERK-1/2 pathway.     

Knockdown of connective tissue growth factor by plasmid-based short hairpin RNA prevented pulmonary vascular remodeling in cigarette smoke-exposed rats

Cigarette smoking may contribute to pulmonary hypertension in chronic obstructive pulmonary disease by resulting in pulmonary vascular remodeling that involves pulmonary artery smooth muscle cell proliferation. Connective tissue growth factor (CTGF) is a cysteine-rich peptide implicated in several biological processes such as cell proliferation, survival, and migration. This study investigated the potential role of CTGF in pulmonary vascular remodeling. We constructed a plasmid-based short hairpin RNA (shRNA) to knock down the expression of CTGF in primary cultured rat pulmonary artery smooth muscle cells (rPASMCs) and in rat lung vessels. Rat PASMCs were challenged with cigarette smoke extract (CSE). Rats were exposed to cigarette smoke for 3 months in the absence or in the presence of plasmid-based short hairpin RNA against CTGF which was administrated by tail vein injection. CTGFshRNA significantly prevented CTGF and cyclin D1 expression, arrested cell cycle at G0/G1 phase and suppressed cell proliferation in rPASMCs exposed to CSE. CTGFshRNA administration ameliorated pulmonary vascular remodeling, inhibited cigarette smoke-induced CTGF elevation and reversed the cyclin D1 increase in pulmonary vessels in rats. Collectively, our data demonstrated that plasmid-based shRNA against CTGF attenuated pulmonary vascular remodeling in cigarette smoke-exposed rats.     

HIF-1α promotes the proliferation and migration of pulmonary arterial smooth muscle cells via activation of Cx43

The proliferation of pulmonary artery smooth muscle cells (PASMCs) is an important cause of pulmonary vascular remodelling in hypoxia-induced pulmonary hypertension (HPH). However, its underlying mechanism has not been well elucidated. Connexin 43 (Cx43) plays crucial roles in vascular smooth muscle cell proliferation in various cardiovascular diseases. Here, the male Sprague-Dawley (SD) rats were exposed to hypoxia (10% O₂) for 21 days to induce rat HPH model. PASMCs were treated with CoCl₂ (200 µM) for 24 h to establish the HPH cell model. It was found that hypoxia up-regulated the expression of Cx43 and phosphorylation of Cx43 at Ser 368 in rat pulmonary arteries and PASMCs, and stimulated the proliferation and migration of PASMCs. HIF-1α inhibitor echinomycin attenuated the CoCl₂-induced Cx43 expression and phosphorylation of Cx43 at Ser 368 in PASMCs. The interaction between HIF-1α and Cx43 promotor was also identified using chromatin immunoprecipitation assay. Moreover, Cx43 specific blocker (^37,43Gap27) or knockdown of Cx43 efficiently alleviated the proliferation and migration of PASMCs under chemically induced hypoxia. Therefore, the results above suggest that HIF-1α, as an upstream regulator, promotes the expression of Cx43, and the HIF-1α/Cx43 axis regulates the proliferation and migration of PASMCs in HPH.     

LncRNA NRON alleviates atrial fibrosis via promoting NFATc3 phosphorylation

Abnormal proliferation of pulmonary artery smooth muscle cells (PASMCs) plays a dominant role in the development of pulmonary arterial hypertension (PAH). Some studies and our previous work found that disturbance of fatty acid metabolism existed in PAH. However, the mechanistic link between fatty acid catabolism and cell proliferation remains elusive. Here, we identified an essential role and signal pathway for the key rate-limiting enzyme of mitochondrial fatty acid β-oxidation, carnitine palmitoyltransferase (CPT) 1, in regulating PASMC proliferation in PAH. We found that CPT1 was highly expressed in rat lungs and pulmonary arteries in monocrotaline-induced PAH, accompanied by decreased adenosine triphosphate (ATP) production and downregulation of the AMPK-p53-p21 pathway. Platelet-derived growth factor (PDGF)-BB upregulated the expression of CPT1 in a dose- and time-dependent manner. PASMC proliferation and ATP production induced by PDGF-BB were partly reversed by the CPT1 inhibitor etomoxir (ETO). The overexpression of CPT1 in PASMCs also promoted proliferation and ATP production and subsequently inhibited the phosphorylation of AMPK, p53, as well as p21 in PASMCs. Furthermore, AMPK was activated by ETO, which increased the expression of p53 and p21, and the proportion of cells in the cell cycle G₂/M phase in response to PDGF-BB stimulation in PASMCs. Our work reveals a novel mechanism of CPT1 regulating PASMC proliferation in PAH, and regulation of CPT1 may be a potential target for therapeutic intervention in PAH.

     

内质网应激促进肺动脉平滑肌细胞的表型转化

目的:探讨内质网应激(ERS)对肺动脉平滑肌细胞表型转化的影响。方法:采用胶原酶Ⅰ消化法培养原代大鼠肺动脉平滑肌细胞(PASMCs),用衣霉素(TM)或4-苯基丁酸(4-PBA)诱导或抑制内ERS,MTS法评价细胞增殖情况,western blot和定量RT-PCR检测蛋白和mRNA表达情况。结果:TM呈浓度依赖性诱导内质网应激标志物GRP78和XBP1 mRNA表达;较低浓度的TM促进PASMCs增殖,高浓度(5μg/mol)使细胞凋亡;TM使PASMCs表达SM22 alpha减少,分泌Ⅰ型胶原增加;4-PBA预处理可逆转TM诱导PASMCs的SM22 alpha减少和Ⅰ型胶原分泌增加。结论:内质网应激促进肺动脉平滑肌细胞表型转化,可能是内质网应激参与肺动脉高压的机制之一。     

alpha1A-adrenoceptor is involved in norepinephrine-induced proliferation of pulmonary artery smooth muscle cells via CaMKII signaling

Pulmonary arterial hypertension (PAH) is a progressive disease of the pulmonary vasculature characterized by excessive proliferation of pulmonary artery smooth muscle cells (PASMCs). Some studies have demonstrated the sympathetic nervous system is activated in PAH and norepinephrine (NE) released is closely linked with its activation. However, the subtypes of adrenoreceptor (AR) and the downstream molecular cascades which are involved in the proliferation of PASMCs are still unclear. In this study, adult male Wistar rats were exposed to chronic hypoxia and PASMCs were cultured in hypoxic condition. Significant upregulation of α_1A-AR was identified by Western blot analysis or immunofluorescence in all of the pulmonary arteries, lung tissues, and cell hypoxic models. Western blot analysis, flow cytometry, and immunofluorescence were applied to detect the roles of α_1A-AR in NE mediated proliferation of PASMCs. We revealed 5-methylurapidil (5-MU) reversed NE-induced upregulation of PCNA, CyclinA and CyclinE, more cells from G₀/G₁ phase to G₂/M+S phase, enhancement of the microtubule formation. In addition, we found calcium/calmodulin(CaM)-dependent protein kinase type II (CaMKII) pathway was involved in α_1A-AR-mediated cell proliferation. [Ca²⁺]_i measurements showed that an increase of [Ca²⁺]_i caused by NE or/and hypoxia could be blocked by 5-MU in PASMCs. Western blot analysis results demonstrated the augmentation of CaMKII phosphorylation level was caused by hypoxia or NE in pulmonary arteries, lung tissues, and PASMCs. KN62 attenuated NE-induced proliferation of PASMCs under normoxia and hypoxia. In conclusion, those results suggested NE which stimulated α_1A-AR-mediated the proliferation of PASMCs, which may be via the CaMKII pathway, and it could be used as a novel treatment strategy in PAH.