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1.
血管生成素(angiopoietin,Ang)是特异性作用于血管内皮细胞的生长因子,主要由Ang-1和Ang-2组成;Tie2(tyrosinekinasethatcontainsim-munoglubin-likeloopsandepidermalgrowthfac-tor-similardomains2)是其共同受体。Ang-1促使血管成熟,维持血管稳定。Ang-2则拮抗Ang-1的作用,始动病理性新生血管形成。在眼部新生血管形成过程中Ang/Tie2受体途径起重要作用,抑制Ang/Tie2受体途径可以抑制眼部新生血管形成。 相似文献
2.
目的:探讨人血管生成素-1(angiopoietin-1,Ang-1)对人脐静脉内皮细胞(human umbilican vein endothelia cell,HUVEC)增殖和凋亡的影响,以进一步研究其生物学作用及其在肿瘤发生中的作用机制.方法:构建pcDNA3.1-V5-HisC-Ang-1真核表达载体,并瞬时转染293细胞;取新生儿脐带经胶原酶消化等方法分离培养HUVEC;分别通过MTT比色和细胞计数法,分析Ang-1瞬时转染上清对HUVEC增殖的影响;通过流式细胞仪分析在血浆饥饿实验条件下,Ang-1对HUVEC凋亡的影响.结果:成功克隆了Ang-1基因,构建了其正义真核表达载体,并在293细胞中瞬时表达;成功进行了HUVEC的原代分离及传代培养;MTT法检测HUVEC增殖结果:只加培养液组、加空载体转染上清组、加Ang-1转染上清组HUVEC OD490值分别为0.36±0.11,0.40±0.03,0.68±0.10(P<0.05);细胞计数法检测结果依次为:(10.13±2.06)×104,(8.7±1.73)×104,(15.03±1.98)×104(P<0.05).流式细胞仪检测HUVEC凋亡率依次为:21%,19%和6%.结论:Ang-1能显著促进血管内皮细胞体外增殖,抑制血浆饥饿时HUVEC的凋亡. 相似文献
3.
Emmi Kapiainen Harri Elamaa Ilkka Miinalainen Valerio Izzi Lauri Eklund 《Investigative ophthalmology & visual science》2022,63(11)
PurposeDefects in the iridocorneal angle tissues, including the trabecular meshwork (TM) and Schlemm''s canal (SC), impair aqueous humor flow and increase the intraocular pressure (IOP), eventually resulting in glaucoma. Activation of endothelial tyrosine kinase receptor Tie2 by angiopoietin-1 (Angpt1) has been demonstrated to be essential for SC formation, but roles of the other two Tie2 ligands, Angpt2 and Angpt4, have been controversial or not yet characterized, respectively.MethodsAngpt4 expression was investigated using genetic cell fate mapping and reporter mice. Congenital deletion of Angpt2 and Angpt4 and tamoxifen-inducible deletion of Angpt1 in mice were used to study the effects of Angpt4 deletion alone and in combination with the other angiopoietins. SC morphology was examined with immunofluorescent staining. IOP measurements, electron microscopy, and histologic evaluation were used to study glaucomatous changes.Results Angpt4 was postnatally expressed in the TM. While Angpt4 deletion alone did not affect SC and Angpt4 deletion did not aggravate Angpt1 deletion phenotype, absence of Angpt4 combined with Angpt2 deletion had detrimental effects on SC morphology in adult mice. Consequently, Angpt2−/−;Angpt4−/− mice displayed glaucomatous changes in the eye. Mice with Angpt2 deletion alone showed only moderate SC defects, but Angpt2 was necessary for proper limbal vasculature development. Mechanistically, analysis of Tie2 phosphorylation suggested that Angpt2 and Angpt4 cooperate as agonistic Tie2 ligands in maintaining SC integrity.ConclusionsOur results indicated an additive effect of Angpt4 in SC maintenance and Tie2 activation and a spatiotemporally regulated interplay between the angiopoietins in the mouse iridocorneal angle. 相似文献
4.
Expression of angiopoietin‐like protein 4 at the fracture site: Regulation by hypoxia and osteoblastic differentiation
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Sabrina S. Wilson Alice Wong Chrisoula A. Toupadakis Clare E. Yellowley 《Journal of orthopaedic research》2015,33(9):1364-1373
Vascular disruption that occurs as a consequence of bone fracture, leads to hypoxia at the site of damage. Hypoxia regulates the expression of a number of genes that can modulate energy conservation, cell survival, tissue regeneration and angiogenesis. In this study we investigated the expression of Angiopoietin‐like 4, an adipocytokine that has additional roles in angiogenesis, at the fracture site. We demonstrate that Angptl4 mRNA expression increased early during fracture healing (day 3) returning close to baseline at day14. In the callus, Angptl4 mRNA was visualized in areas of condensing mesenchymal cells, callus cartilage and was especially high in mineralizing osteoblasts located in areas of new bone formation. In vitro, Angptl4 mRNA expression in osteoblasts increased under hypoxic conditions and in cells treated with the hypoxia mimetic desferrioxamine. Angptl4 levels were strongly induced at day 14 in differentiating MC3T3‐E1 osteoblastic cells. Exogenous ANGPTL4 increased expression of Runx2, Spp1, vegfa, and Alp mRNA in differentiating osteoblasts. We suggest that the distribution of Angptl4 in the callus may be driven by hypoxia and that Angptl4 may play a role in osteoblastic differentiation, and possibly angiogenesis via regulation of VEGF. Further studies could reveal a dual role for Angptl4 in angiogenesis and osteogenesis. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1364–1373, 2015. 相似文献
5.
Chandra C. Ghosh Sascha David Ruyang Zhang Anthony Berghelli Katelyn Milam Sarah J. Higgins Jon Hunter Aditi Mukherjee Yongyue Wei Mei Tran Freeman Suber Lester Kobzik Kevin C. Kain Shulin Lu Ansgar Santel Kiichiro Yano Prajna Guha Daniel J. Dumont David C. Christiani Samir M. Parikh 《Proceedings of the National Academy of Sciences of the United States of America》2016,113(9):2472-2477
Ligands of the endothelial-enriched tunica interna endothelial cell kinase 2 (Tie2) are markedly imbalanced in severe infections associated with vascular leakage, yet regulation of the receptor itself has been understudied in this context. Here, we show that TIE2 gene expression may constitute a novel vascular barrier control mechanism in diverse infections. Tie2 expression declined rapidly in wide-ranging models of leak-associated infections, including anthrax, influenza, malaria, and sepsis. Forced Tie2 suppression sufficed to attenuate barrier function and sensitize endothelium to permeability mediators. Rapid reduction of pulmonary Tie2 in otherwise healthy animals attenuated downstream kinase signaling to the barrier effector vascular endothelial (VE)-cadherin and induced vascular leakage. Compared with wild-type littermates, mice possessing one allele of Tie2 suffered more severe vascular leakage and higher mortality in two different sepsis models. Common genetic variants that influence TIE2 expression were then sought in the HapMap3 cohort. Remarkably, each of the three strongest predicted cis-acting SNPs in HapMap3 was also associated with the risk of acute respiratory distress syndrome (ARDS) in an intensive care unit cohort of 1,614 subjects. The haplotype associated with the highest TIE2 expression conferred a 28% reduction in the risk of ARDS independent of other major clinical variables, including disease severity. In contrast, the most common haplotype was associated with both the lowest TIE2 expression and 31% higher ARDS risk. Together, the results implicate common genetic variation at the TIE2 locus as a determinant of vascular leak-related clinical outcomes from common infections, suggesting new tools to identify individuals at unusual risk for deleterious complications of infection.Among vascular-enriched receptor tyrosine kinases, Tie2 is unusual in at least two functional aspects. First, Tie2 phosphorylation is tightly controlled by the interplay of several proteins: a paralogous receptor, Tie1; a tyrosine phosphatase, vascular endothelial-protein tyrosine phosphatase (VE-PTP); and two secreted ligands, angiopoietin (Angpt)-1 and Angpt-2, the latter of which can act as an agonist, partial agonist, or antagonist depending upon context (1–6). Second, unlike classic growth factor receptors, Tie2 is heavily expressed and phosphorylated throughout the quiescent adult vasculature (7), suggesting that Tie2 signaling has one or more roles in vascular maintenance.Based largely on Angpt-1 overexpression studies, Tie2 has been implicated in vascular barrier defense (8, 9). However, adult-specific deletion of Angpt-1 does not appear to trigger vascular leakage (10). Moreover, Angpt-1 has repeatedly been ascribed functions that are independent of Tie2 (11–13). Finally, observational studies in humans suffering clinical manifestations of vascular leakage have consistently shown a marked imbalance in Tie2 ligands tilting in favor of Angpt-2 (reviewed in 14). Although decreased Tie2 activity has been inferred from these reports, the role of TIE2 gene expression has not been directly queried experimentally or in clinical settings.This question is important not only for understanding control mechanisms of the circulatory system but also to guide the development of strategies to predict, stratify, and treat patients affected by acute vascular leakage. If tonic Tie2 signaling is indeed necessary for vascular barrier maintenance, then reducing the pool of receptors could constitute a ligand-independent means to attenuate barrier-protective signaling in the endothelium. We therefore hypothesized that the level of Tie2 expression modulates the sensitivity of blood vessels, and thereby the entire organism, to noxious stimuli. Cellular, rodent, and human genetics studies were undertaken to test this concept. 相似文献
6.
目的探讨心力衰竭患者血浆补体C1q肿瘤坏死因子相关蛋白3(C1q tumor necrosis factor related proteins-3,CTRP3)、血管生成素样蛋白2(angiopoietin like protein 2,angptl2)、可溶性致癌抑制因子2(soluble suppression of tumorigenicity 2,sST2)的浓度及预后价值。方法选择2014年8月到2018年2月在北京市垂杨柳医院心内科收治的心力衰竭患者122例作为心力衰竭组,并分为收缩性心力衰竭组62例和舒张性心力衰竭组60例两个亚组;对照组为非心力衰竭人群122例。采用酶联免疫吸附法检测混杂血浆CTRP3、angptl2、sST2浓度,随访调查患者的预后并进行相关性分析与预测价值分析。结果心力衰竭组的左心室射血分数(left ventricular ejection fraction,LVEF)低于对照组,左心室舒张末期内径(left ventricular end diastolic dimension,LVEDD)及血尿素、肌酐浓度高于对照组,差异有统计学意义(P<0.05)。两组总胆固醇、低密度脂蛋白胆固醇浓度比较,差异无统计学意义(P>0.05)。两亚组心功能与生化指标比较,差异无统计学意义(P>0.05)。心力衰竭组的血浆angptl2、sST2浓度高于对照组,CTRP3浓度低于对照组,差异有统计学意义(P<0.05);两亚组CTRP3、angptl2、s ST2浓度比较,差异无统计学意义(P>0.05)。随访至今,心力衰竭组患者中预后不良16例,发生率为13.1%。Pearson相关分析结果显示CTRP3、angptl2、sST2、LVEF、LVEDD、尿素、肌酐都与心力衰竭患者预后显著相关(P<0.05)。Cox回归模型分析显示CTRP3、angptl2、sST2为影响心力衰竭患者预后的主要因素(P<0.05)。结论心力衰竭患者血清CTRP3、angptl2、sST2浓度呈现异常表达情况,具有预测预后不良的价值,是心力衰竭预后评估的生物学标志物。 相似文献
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8.
Background. A continuous increase in number of CKD patients entering ESRD is a growing public health threat, which reflects the present therapeutic failure usually initiating at the late stage of CKD. Objective. To study the mechanism of vascular repair in CKD patients associated with mildly impaired renal function, which included angiogenic factors such as VEFG, angiopoietin-1, and flt-1 (VEGFR1); and antiangiogenic factors such as angiopoietin-2 and KDR (VEGFR2). Results. A mild defect in angiogenic factor—namely, angiopoietin-1—was observed, whereas VEGF and flt-1 (VEGFR1) were within normal limit. Also, antiangiogenic factor—namely, angiopoietin-2—was mildly elevated, whereas KDR (VEGFR2) remained within normal limit. Conclusion. The mechanism of vascular repair appears to be adequately functional in the early stage of CKD. Therapeutic intervention at this stage can improve renal perfusion and restore renal function as indicated in normoalbuminuric, type 2 diabetic nephropathy. The authors encourage changing the conceptual view of treatment under common treatment at late stage of CKD to treatment at early stage of CKD under an environment favorable for renal regeneration. 相似文献
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10.
目的 探讨血清血管生成素1(Ang-1)与血管生成素2(Ang-2)比值对2型糖尿病(T2DM)微血管病变的诊断价值。方法 选取2018年1-12月期间在山西医科大学附属第二医院(下称本院)接受治疗的T2DM患者98例,根据是否合并微血管病变将98例患者分为微血管病变组(42例)和单纯T2DM组(56例),另选取同期在本院体检的健康人群50例作为对照组。检测各组研究对象的空腹血糖(FPG)、糖化血红蛋白(HbA1c)、空腹胰岛素(FINS)、胰岛素抵抗指数(HOMA-IR)、Ang-1、Ang-2、Ang-1/Ang-2。结果 微血管病变组的体质量指数、FPG、HbA1c、HOMA-IR、Ang-2均高于单纯T2DM组和对照组,Ang-1/Ang-2低于单纯T2DM组和对照组,差异有统计学意义(P<0.05),微血管病变组的病程长于单纯T2DM组,FINS高于对照组,差异有统计学意义(P<0.05),单纯T2DM组的体质量指数、FPG、FINS、HbA1c、HOMA-IR、Ang-2均高于对照组,Ang-1/Ang-2低于对照组,差异有统计学意义(P<0.05),Ang-2与病程、HbA1c呈正相关(r分别为0.421、0.391,P<0.05),Ang-1/Ang-2与病程、HbA1c呈负相关(r分别为-0.548、-0.423,P<0.05),Ang-1、Ang-2、Ang-1/Ang-2曲线下的面积分别为0.625、0.737、0.902,约登指数分别为0.134、0.549、0.744。结论 血清Ang-2在T2DM微血管病变患者中呈高表达,而Ang-1/Ang-2则明显降低,且Ang-1/Ang-2对T2DM患者微血管病变有较高的诊断价值。 相似文献