NT4-TAT-His-PR39融合基因cDNA的构建及意义

目的: 探讨PR39对急性缺血心肌的保护作用,构建可分泌表达PR39的神经生长因子4（NT4）-TAT-His-PR39融合基因cDNA。方法: 采用互为模板、引物的PCR技术,制备两端含有酶切位点的PR39 cDNA片段。通过常规分子生物学方法,将其与编码NT4信号肽及引导肽、TAT及6×His基因序列用T4 DNA连接酶相连,将NT4-TAT-His-PR39装入质粒pBV220中。结果: 融合基因NT4-TAT-His-PR39的长度为421 bp,限制性内切酶切图谱显示,目的带的大小略超过marker的400 bp的位置,证实已经成功地将PR39 cDNA重组到NT4-TAT-His序列的下游。基因测序结果及DNAsis软件分析结果表明,NT4-TAT-His-PR39的全序列与实验设计的序列完全一致。结论: 成功地构建能分泌表达PR39、并具穿膜功能和标签的融合基因NT4-TAT-His-PR39。     

大鼠脑缺血及缺氧预处理对HIF-1α表达的影响

目的探讨脑缺血及脑缺氧预处理后HIF-1α表达的变化及其意义。方法建立大鼠局灶性脑缺血及脑缺氧预处理模型。随机分为正常对照组、缺氧预处理组（8%O2、92%N2,3h）、局灶性缺血组、缺氧预处理＋局灶性脑缺血组。其中后两组又根据缺血时间不同分为6h、1、3、7d。应用普通病理、免疫组化和原位杂交技术,观察大鼠脑缺血及缺氧预处理后HIF-1α表达变化。结果脑组织中HIF-1α蛋白及 mRNA表达可见于存活和坏死的神经细胞、血管内皮细胞、胶质细胞。脑缺血缺氧诱导了HIF-1α的表达,以缺血周边区表达最为明显（P〈0.05）。结论缺氧预处理后HIF-1α在周边区表达增强,其表达可见于神经细胞、血管内皮细胞及胶质细胞,提示HIF-1α的激活转录是缺氧预处理的脑保护机制之一。     

重组腺病毒介导的缺氧诱导因子-1α对脑缺氧后神经元中缺氧诱导因子-1α的调控

目的探讨重组腺病毒介导的缺氧诱导因子-1α(HIF-1α)转染对缺氧后的大鼠大脑皮层神经元中HIF-1α的调控作用及可能机制。方法 (1)制备大鼠大脑皮层神经元原代培养模型及缺氧模型。重组腺病毒缺氧诱导因子-1α(AdHIF-1α)转染和重组腺病毒空载体(Ad)转染正常及缺氧细胞;将其分为正常对照组(Normal)、缺氧组(Hypoxia)、AdHIF-1α基因转染组、Ad组。(2)荧光显微镜下观察AdHIF-1α/Ad转染情况;采用蛋白印迹(Western blot)法分别在12 h、24 h、48 h及72 h观察各实验组HIF-1α蛋白的表达。结果用Ad/AdHIF-lα转染缺氧的神经元后, 在荧光显微镜下观察转染48 h时荧光表达最明显。Western blot检测经AdHIF-1α基因转染组各时间点HIF-1α的表达明显增加, 12 h有阳性表达, 24 h表达有所增加, 48 h达高峰, 持续到72 h开始下降, 与缺氧组相比差异均有统计学意义(P<0.01, P<0.05), Ad组与缺氧组相比无统计学意义。结论重组腺病毒介导的HIF-1α基因转染能明显提高缺...     

1缺氧诱导因子-1α反义寡核苷酸对新生血管形成的抑制作用

目的:研究缺氧诱导因子-1α反义寡核苷酸对肿瘤血管形成的影响.方法:通过将腺病毒包装的反义HIF-1α(Ad-antiHIF-1α)和腺病毒包装的lacZ标志基因(Ad-lacZ)注射入人大肠癌鸡胚移植模型的鸡胚绒毛尿囊膜(CAM)中,观察他们对鸡胚移植瘤新生血管形成的影响.结果:注射Ad-antiHIF-1α组血管稀疏、纤细,一级血管数(16.8±1.6 vs 45.2±2.8,t=2.42,P=0.02＜0.05)及二级血管数(34.8±3.6 vs 58.4±5.3,t=2.97,P=0.005＜0.01)均明显少于注射Ad-lacZ组.结论:Ad-antiHIF-1α能有效抑制鸡胚移植瘤新生血管的形成.     

硫氧还蛋白对缺氧/复氧人脐静脉内皮细胞的保护作用

目的 探讨硫氧还蛋白(thioredoxin,TRX)对缺氧/复氧损伤内皮细胞(ECV)的保护作用.方法 对体外培养的内皮细胞株ECV304(缺氧/复氧组)及TRX修饰的ECV304(TRX组)进行缺氧/复氧实验,另一组ECV304细胞不作缺氧/复氧作为正常对照组,检测复氧不同时间点细胞培养上清液中丙二醛(MDA)、内皮素-1(ET-1)及一氧化氮(NO)的含量变化.结果 正常对照(ECV304组),细胞内的MDA、ET-1及NO含量在24 h内变化不大；转染空载体的ECV304细胞在缺氧3h时,MDA、ET-1含量显著增加,复氧12 h时,MDA、ET-1含量达到最高,然后缓慢下降；ECV304/Trx组与转染空载体组相比,在3h及12时,MDA含量极显著下降(P＜0.01),而在24 h MDA水平显著下降(P＜0.05).ET-1水平在复氧的各时间点均比有下降,在复氧24 h下降最明显(P＜0.01)；转染空载体的ECV304细胞在缺氧3h时,NO含量显著下降,复氧12 h时,NO含量下降到最低,然后缓慢上升；ECV304/Trx组与转染空载体组相比,在3h及12时,NO含量极显著上升(P＜0.01),在12 h NO水平最高.ECV304/TRX组与正常对照组相比,在12 h时,有显著差异.结论 TRX能抑制缺氧/复氧对ECV的损伤,对缺氧/复氧环境下的ECV起保护作用.     

缺氧诱导因子-1α shRNA 重组质粒的构建及对人结肠癌细胞生长的影响

目的 构建靶向缺氧诱导因子-1α特异性短发卡RNA(shRNA)的真核表达载体,为结肠癌的靶向治疗奠定基础.方法 设计、合成针对缺氧诱导因子-1α的特异性短链寡核苷酸,构建缺氧诱导因子-1α特异性shRNA的重组质粒,稳定转染结肠癌SW480细胞;采用氯化钴制备缺氧诱导培养基,模拟肿瘤缺氧状态.采用实时定量聚合酶链反应和免疫印迹法检测转染前后SW480细胞中缺氧诱导因子-1α的表达;MTT法检测SW480细胞活性.结果 经酶切和测序鉴定,成功构建HIF-1α特异性shRNA的重组质粒,并能转染SW480细胞.转染后,缺氧诱导因子-1α mRNA和蛋白水平表达分别下降约86.1%和79.7%,肿瘤细胞增殖活性明显降低.结论 运用pGenesil-1质粒载体构建的靶向HIF-1α特异性shRNA的重组质粒已成功构建,该质粒可转染SW480细胞,有效抑制HIF-1α的表达;本研究可为结肠癌的靶向治疗提供新方法.     

缺氧对肝癌HepG2细胞内PPARα和HIF-1α表达的影响及机制探讨

目的 观察不同程度缺氧条件下,肝癌HepG2细胞内过氧化物酶体增殖物激活受体α(PPARα)和缺氧诱导因子1α(HIF-1α)的表达,及反义封闭HIF-1α后对PPARα表达的影响.方法 HepG2细胞分为正常对照组(A组)、缺氧24 h组(B组)、缺氧48 h组(C组)、缺氧72 h组(D组).观察各组的PPARα、HIF-1α蛋白和mRNA表达变化.再设计对照组(E组)、HIF-1α反义寡核苷酸组(F组)、HIF-1α正义寡核苷酸组(G组)、HIF-1α错义寡核苷酸组(H组),观察各组HIF-1α对PPARα的表达影响.结果 正常对照组,PPARα和HIF-1α少量表达.随着缺氧时间延长,PPARα和HIF-1α的表达呈现逐渐升高,在缺氧24 h时,mRNA和蛋白开始增高,48 h增高明显,72 h达高峰.反义封闭HIF-1α后,PPARα表达明显下降.结论 PPARα及HIF-1α的表达随肿瘤细胞缺氧信号的加强而增加,PPARα受HIF-1α的调控.     

低氧条件下人成骨细胞长链非编码RNA5'aHIF-1α的表达

目的观察低氧条件下人成骨细胞HIF-1α反义转录物5'aHIF-1α的表达变化,探讨低氧对人成骨细胞分化影响的调控机制。方法采用人成骨肉瘤细胞系(MG63),随机分为4组,分别在不同氧体积分数(10%、6%、3%和1%O2)条件下培养72 h。用Trizol法提取总RNA,用实时荧光定量PCR法检测5'aHIF-1α表达;用Western blot法检测HIF-1α蛋白表达。结果 10%O2组MG63细胞5'aHIF-1α表达水平是对照组(6%O2)的2.06±0.07倍,3%和1%O2组MG63细胞5'aHIF-1α表达水平分别是对照组的0.63±0.08和0.43±0.03倍。10%O2组5'a HIF-1α蛋白表达水平明显降低,3%和1%O2组HIF-1α蛋白表达水平随氧体积分数降低而逐渐升高。结论低氧条件下,长链非编码RNA-5'aHIF-1α可能在转录或转录后水平抑制MG63细胞HIF-1α的表达,但随着氧体积分数的降低,其抑制作用逐渐减弱。     

问号钩端螺旋体毒力基因mviN的表达及细胞毒性作用研究

目的克隆表达问号钩端螺旋体毒力基因mviN并观察表达产物对血管内皮细胞ECV304及肺上皮细胞A549的毒性作用。方法将mviN基因插入原核表达载体pET32a(+),构建重组质粒pET-mviN,转化大肠杆菌BL21(DH3)以高效表达携带组氨酸标签的Trx-MviN融合蛋白,并作亲和层析纯化。以XTT法检测毒力蛋白Trx-MviN对ECV304及A549细胞增殖的抑制作用,同时以流式细胞术检测其作用于ECV304及A549后的细胞凋亡率。结果成功构建了重组质粒pET-mviN并高效表达出Trx-MviN融合蛋白;毒力蛋白Trx-MviN作用于ECV304及A549后,与对照组相比较,其细胞增殖被显著抑制(P<0.05),而细胞凋亡率显著增加(P<0.01)。结论重组质粒pET-mviN高效表达出Trx-MviN融合蛋白,纯化后的融合蛋白Trx-MviN对ECV304及A549具有细胞毒性作用。     

Vasostatin基因对胰腺癌细胞和血管内皮细胞增殖的影响

目的研究Vasostatin转基因对胰腺癌细胞、血管内皮细胞的作用,探讨其对胰腺癌生长抑制的作用机制.方法应用腺病毒载体将Vasostatin基因转入人胰腺癌细胞SW1990、人脐静脉血管内皮细胞ECV304,应用MTT方法检测转基因后细胞的生长活力.同时,应用小管形成实验研究Vasostatin对血管内皮细胞ECV304体外血管生成的影响.结果 Vasostatin转基因对人胰腺癌SW1990细胞生长无显著影响.Vasostatin转基因(MOI分别为25和50)对人脐静脉血管内皮细胞ECV304作用72 h后,Ad-Vasostatin组的ECV304细胞数目显著少于PBS组和Ad-lacZ组(P < 0.05).小管形成实验结果显示,Ad-Vasostatin组内皮细胞数目较少,细胞排列连续性差,可见条索状的细胞链,但中空闭合的管状结构缺如.结论腺病毒介导的Vasostatin基因可显著抑制人脐静脉血管内皮细胞ECV304的体外细胞增殖,抑制其体外血管生成,而对人胰腺癌肿瘤细胞SW1990的体外细胞增殖无明显影响.     

人双突变型低氧诱导因子α促进骨髓间充质干细胞向心肌细胞分化的实验研究

目的 探讨人双突变型低氧诱导因子1α(HIF-1α)基因(HIF-1α-402-564)对与心肌细胞共培养的骨髓间充质干细胞(MSC)向心肌细胞分化的影响.方法 实验分为4组:HIF-1α组(MSC+心肌细胞+Ad-HIF-1α)、LacZ组(MSC+心肌细胞+Ad-Lacz)、Sham组[MSC+心肌细胞+胎牛血清(PBS)]、MSC+HIF-1α组(MSC+Ad-HIF-1α),前三组中MSC与心肌细胞按1:2比例共同培养,各组细胞培养24 h后分别感染不同病毒(MOI=100)或加入PBS液.病毒感染后7 d,免疫细胞化学分析共培养的MSC表达心肌细胞特异性标志物心肌肌钙蛋白T(cTnT)的情况,逆转录聚合酶链式反应(RT-PCR)分析各组细胞HIF-1α、转化生长因子β1(TGF-β1)、Smad4、NKx2.5、GATA结合蛋白4(GATA-4)的mRNA表达量.结果 HIF-1α组MSc心肌细胞分化率为(32.68±6.52)%,显著高于LacZ组[(8.28±0.09)%]和Sham组[(10.25±2.20)%],P均<0.05,MSC±HIF-1α组仅为(0.32±0.05)%.LacZ组和Sham组间差异无统计学意义.MSC+HIF-1α组与Sham组比较,差异有统计学意义(P<0.05).HIF-1α组TGFβ1及Smad4 mRNA表达水平明显高于其余各组,P均<0.05.HIF-1α组NKx2.5和GATA-4 mRNA表达水平明显高于Sham组,P均<0.05.结论 HIF-1α能够促进与心肌细胞共培养的MSC向心肌细胞分化,TGF-β1/Smad4信号通路参与了该过程.     

Constitutive HIF-1α Expression Blunts the Beneficial Effects of Cardiosphere-Derived Cell Therapy in the Heart by Altering Paracrine Factor Balance

Hypoxia-inducible factor-1alpha (HIF-1α) expression promotes angiogenesis and can influence stem cell engraftment. We investigated the effect of stable over-expression of constitutively active HIF-1α on cardiosphere-derived cell (CDC) engraftment and left ventricular function. CDCs were transduced with a lentivirus expressing a constitutively active mutant of human HIF-1α (LVHIF-1α). Two million male rat CDCs were injected into the infarct following ligation of the mid-LAD in female syngeneic rats. Left ventricular ejection fraction (EF) and circumferential strain were measured by echocardiography at 1 and 4 weeks post-MI in the following groups: PBS group (n = 7), CELL group (n = 7), and CELL-HIF group (n = 7). HIF-1α, VEGF, endothelin-1 expression, and CDC engraftment were measured by quantitative PCR. At 30 days, EF was unchanged in the CELL-HIF group (p = NS), increased in the CELL group (p = 0.025), and decreased in the PBS group (p = 0.021), but engraftment was similar (2.4% ± 3.3% vs 1.7% ± 0.8%, p = NS). Mean circumferential strain of the infarcted region was unchanged in the CELL-HIF group, but improved in the CELL group (p = 0.02). Endothelin-1 and VEGF expression were higher in HIF-CDCs exposed to hypoxia, compared with non-transduced CDCs. HIF-1α expression in CDCs blunted the beneficial functional effects of CDC transplantation, suggesting that paracrine factor balance may play an important role in cardiac regeneration.     

5-Fu对低氧下胃癌SGC7901细胞系中SP细胞比例及HIF-2、ABCG2表达的影响

目的:探讨低氧下5-Fu化疗抵抗的机制.方法:MTT检测常氧和低氧下的细胞活力,并计算5-Fu的半数抑制浓度(IC50).以IC50的5-Fu分别作用细胞常氧和低氧组细胞24、48和72h后,收集标本,Hoechst33342染色法检测侧群(side population,SP)细胞的比例,免疫细胞化学法检测低氧诱导因子(hypoxia-inducible factor-2α,HIF-2α),荧光免疫细胞化学法检测ABCG2(ATP-binding cassettesuperfamily Gmember 2)的表达.结果:常氧和低氧下,5-Fu均呈时间、剂量依赖性地抑制SGC7901细胞增殖,其IC50分别为100、200mg/L.常氧下SP细胞的比例为1.87%,低氧诱导后其比例逐渐增加.常氧下5-Fu-IC50作用于细胞不用时间后,SP细胞的比例无明显变化,低氧下其比例却逐渐增加.常氧下,HIF-2和ABCG2蛋白呈低水平表达,且5-Fu-IC50作用于不同时间后也无明显变化,低氧下5-Fu-IC50作用于不同时间后二者的表达逐渐增加.结论:低氧下5-Fu对胃癌SGC7901细胞存在化疗抵抗可能与低氧通过诱导HIF-2α-ABCG2通路的表达、促进肿瘤细胞的干细胞化有关,这可能是肿瘤化疗抵抗和复发的根源.     

Treatment of pancreatic carcinoma by adenoviral mediated gene transfer of vasostatin in mice

BACKGROUND: Tumour growth is angiogenesis dependent and antiangiogenesis therapy may represent a promising therapeutic option. AIMS: To evaluate the inhibitory effect of vasostatin gene mediated by a replication deficient recombinant adenovirus (Ad) on human pancreatic cancer in vivo and to investigate the mechanism of action of vasostatin. METHODS: Human umbilical vein endothelium derived ECV304 cells were infected with Ad-vasostatin and Ad-lacZ, and compared with phosphate buffered saline (PBS). MTT (3,-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay was used to estimate the proliferation of ECV304 cells; tube formation assay and choriallantoic membrane assay were used to evaluate angiogenesis in vivo and in vitro. Xenografted nude mice with pancreatic cancer were established to observe in vivo tumour growth suppression. Microvessel density revealed by CD31 immunohistochemical staining was measured. RESULTS: Growth and tube formation of ECV304 cells infected with Ad-vasostatin were suppressed significantly compared with cells infected with Ad-lacZ or cells treated with PBS. Neovascularisation in the Ad-vasostatin group was less than that in the PBS and Ad-lacZ groups, based on chorioallantoic membrane results. Volumes of pancreatic tumours in the Ad-vasostatin group were significantly smaller than those in the PBS and Ad-lacZ groups at the end of the treatment period. Microvessel density in the Ad-vasostatin group was significantly lower than that in the Ad-lacZ and PBS groups. CONCLUSION: The vasostatin gene mediated by adenovirus is efficient for gene therapy for pancreatic carcinoma. Suppression of vasostatin on proliferation of vascular endothelium cells and angiogenesis may account for its effect.     

Hypoxia-inducible factor-1 up-regulates the expression of Toll-like receptor 4 in pancreatic cancer cells under hypoxic conditions

Background & aimsHypoxia is a common characteristic of solid tumors. Recent studies confirmed that Toll-like receptor 4 (TLR4) plays a significant role in cancer invasion and progression. In this study, the correlation between the expression of TLR4 and the change of the protein level of Hypoxia-inducible factor-1 alpha (HIF-1α) was studied.MethodsWe examined 84 human pancreatic cancer tissues for expression of HIF-1α and TLR4 proteins. Panc-1 cells were exposed to normoxia (20% O₂) or hypoxia (<1% O₂) or treated with CoCl₂. TLR4 protein was analyzed by flow cytometry and immunostaining. Growth studies were conducted on cells with the HIF-1α inhibition isolated from stable transfected cell lines. Finally, TLR4 protein was detected by immunohistochemistry in vivo tumors.ResultsThere was a positive correlation between TLR4 and HIF-1α protein in pancreatic cancer tissues. Hypoxic stress induced TLR4 mRNA and protein expression in Panc-1 cells. Cells transfected with HIF-1α siRNA showed attenuation of hypoxia stress-induced TLR4 expression. In vivo growth decreased in response to TLR4 and HIF-1α inhibiton. Transient HIF-1α siRNA treatment could effectively curb tumor growth in vivo.ConclusionThese results suggest that TLR4 expression in pancreatic cancer cells is up-regulated via HIF-1α in response to hypoxic stress and underscore the crucial role of HIF-1α-induced TLR4 in tumor growth.     

Hypoxic stress tolerance of the blind subterranean mole rat: expression of erythropoietin and hypoxia-inducible factor 1 alpha

Blind subterranean mole rats (Spalax, Spalacidae) evolved adaptive strategies to cope with hypoxia that climaxes during winter floods in their burrows. By using real-time PCR, we compared gene expression of erythropoietin (Epo), a key regulator of circulating erythrocytes, and hypoxia-inducible factor 1 alpha (HIF-1 alpha), Epo expression inducer, in the kidneys of Spalax and white rats, Rattus norvegicus. Our results show significantly higher, quicker, and longer responses to different O(2) levels in Spalax compared with Rattus. (i) In normoxia, both Spalax and Rattus kidneys produce small amounts of Epo. Maximal expression of Rattus Epo is noticed after a 4-h hypoxia at 6% O(2). Under these conditions, Spalax Epo levels are 3-fold higher than in Rattus. After 24 h of 10% O(2), Spalax Epo reaches its maximal expression, remarkably 6-fold higher than the maximum in Rattus; (ii) the HIF-1 alpha level in normoxia is 2-fold higher in Spalax than in Rattus. Spalax HIF-1 alpha achieves maximal expression after 4-h hypoxia at 3% O(2), a 2-fold increase compared with normoxia, whereas no significant change was detected in Rattus HIF-1 alpha at any of the conditions studied; (iii) at 6% O(2) for 10 h, in which Rattus cannot survive, Epo and HIF-1 alpha levels in Spalax galili, living in heavily flooded soils, are higher than in Spalax judaei, residing in light aerated soil. We suggest that this pattern of Epo and HIF-1 alpha expression is a substantial contribution to the adaptive strategy of hypoxia tolerance in Spalax, evolved during 40 million years of evolution to cope with underground hypoxic stress.     

缺氧—复氧诱导ECV304细胞与中性粒细胞粘附的分子机制

为探讨缺氧-复氧诱导人脐静脉内皮细胞ECV304与中性粒细胞粘附的信号转导机制，以缺氧-复氧诱导粘附为模型，采用比色法检测粘附率，流式细胞术检测ECV304细胞表面粘附分子E选择素、细胞问粘附分子1的表达，Western blot法检测ECV304细胞亲环素A、磷酸化细胞外信号调节激酶、总细胞外信号调节激酶、磷酸化D70核糖体S6激酶、总p70核糖体S6激酶蛋白的表达。结果发现，经缺氧-复氧处理后，ECV304细胞E选择素、细胞间粘附分子1的表达上调，其表面中性粒细胞粘附增加。总细胞外信号调节激酶、总p70核糖体S6激酶蛋白表达无明显改变，亲环素A蛋白表达明显上调，细胞外信号调节激酶和p70核糖体S6激酶显著活化。亲环素A抑制剂环孢霉素A以及亲环素A反义寡核苷酸均明显减轻缺氧-复氧诱导的细胞外信号调节激酶和p70核糖体S6激酶激活，显著减少ECV304细胞与中性粒细胞粘附。p70核糖体S6激酶阻断剂雷帕霉素显著抑制p70核糖体S6激酶的激活，中性粒细胞与ECV304细胞的粘附亦明显减少。细胞外信号调节激酶信号通路特异性阻断剂PD98059亦显著抑制ECV304细胞与中性粒细胞粘附。结果提示，亲环素A-细胞外信号调节激酶-p70核糖体S6激酶信号通路介导缺氧-复氧诱导的ECV304细胞与中性粒细胞粘附。     

Suppression of NHE1 by small interfering RNA inhibits HIF-1α-induced angiogenesis in vitro via modulation of calpain activity

Hypoxia-inducible factor-1 (HIF-1) orchestrates angiogenesis under hypoxic conditions mainly due to increased expression of such target genes as vascular endothelial growth factor (VEGF). Na+/H + exchanger-1 (NHE1), a potential HIF target gene product, plays a pivotal role in proliferation, survival, migration, adhesion and so on. However, it is unknown whether NHE1 is involved in HIF-1α-induced angiogenesis. This present study demonstrated that the expression of NHE1 was much higher in human umbilical vein endothelial cells (HUVECs) infected with adenovirus encoding HIF-1α (rAd-HIF) than with vacuum adenovirus (vAd). HIF-1α also increased the expression of VEGF, the expression and activity of calpains, and the intracellular pH. Moreover, small interfering RNA targeting NHE1 (NHE1 siRNA) dramatically decreased the expression of NHE1 and thus lowered the intracellular pH, and it also attenuated the protein expression of calpain-2 but not calpain-1, resulting in the lower calpain activity. Furthermore, HIF-1α enhanced the proliferation, migration and Matrigel tube formation, which were inhibited by NHE1 siRNA. Finally, the inhibitory effect of NHE1 siRNA was reversed by VEGF and the reversibility of the later was abrogated by the calpain inhibitor ALLM. In conclusion, the findings have revealed that NHE1 might participate in HIF-1-induced angiogenesis due, at least in part, to the alteration of the calpain activity, suggesting that NHE1 as well as calpains might represent a potential target of controlling angiogenesis in response to the hypoxic stress under various pathological conditions.