Determination of plasma concentrations of endothelin-1(1-31) and endothelin-1 in healthy subjects and patients with atherosclerosis

We previously found that human chymase cleaves big endothelins at the Tyr31-Gly32 bond and produces 31-amino-acid endothelins, endothelins(1-31). Endothelin-1(1-31) has been isolated from a number of human organs, including the heart and lungs. As endothelin-1 has been shown to play a significant role in the paracrine regulation of cardiovascular functions in humans, it is possible that endothelin-1(1-31) may also exhibit biological activity on human tissues. We previously reported that synthetic endothelin-1(1-31) exhibits a number of physiological actions on cultured cells in vitro. In the present study, we investigated the plasma concentrations of endothelin-1(1-31) and endothelin-1 in healthy subjects and compared them with those in patients with cardiovascular diseases. Endothelin-1(1-31) and endothelin-1 in human plasma was measured using a sandwich-enzyme-immunoassay system, which was recently described for measurement of endothelin-1(1-31). The plasma concentrations of endothelin-1(1-31) and endothelin-1 in healthy volunteers were 19.24 +/- 5.70 and 15.54 +/- 4.45 pg/ml (n = 5), respectively. We also measured plasma concentrations of endothelin-1(1-31) and endothelin-1 before and after surgery in patients with abdominal aortic aneurysms. Before surgery, plasma concentrations of endothelin-1(1-31) and endothelin-1 in these patients were higher than those in healthy individuals. After surgery, both endothelin-1(1-31) and endothelin-1 in plasma decreased to levels similar to those of healthy subjects. This suggests that endothelin-1(1-31) may have similar physiological significance to endothelin-1 in patients with atherosclerosis.     

Enzymatic pathways involved in the generation of endothelin-1(1-31) from exogenous big endothelin-1 in the rabbit aorta

We investigated whether blood vessels contribute to the production of ET-1(1-31) from exogenous big endothelin-1 (BigET-1) in the rabbit and assessed which enzymes are involved in this process. Vascular reactivity experiments, using standard muscle bath procedures, showed that BigET-1 induces contraction in endothelium-intact rabbit aortic rings. Preincubation of the rings with phosphoramidon, CGS35066 or thiorphan reduced BigET-1-induced contraction. Conversely, chymostatin did not affect BigET-1-induced contraction. Thiorphan and phosphoramidon, but not CGS35066 or chymostatin, reduced ET-1(1-31)-induced contraction. None of the enzymatic inhibitors affected the contraction afforded by ET-1.BQ123-, but not BQ788-, selective antagonists for ET(A) and ET(B) receptors, respectively, produced concentration-dependent rightward displacements of the ET-1(1-31) and ET-1 concentration-response curves. By the use of enzymatic assays, we found that the aorta, as well as the heart, lung, kidney and liver, possess a chymase-like activity. Enzyme immunoassays detected significant levels of Ir-ET-1(1-31) in bathing medium of aortas after the addition of BigET-1 (30 nM). Neither thiorphan nor chymostatin altered the levels of Ir-ET-1(1-31). Conversely, the levels of Ir-ET-1(1-31) were increased in the presence of phosphoramidon. This marked increase of the 31-amino-acid peptide was abolished when phosphoramidon and chymostatin were added simultaneously. The major new finding of the present work is that the rabbit aorta generates ET-1(1-31) from exogenously administered BigET-1. Additionally, by measuring the production of ET-1(1-31), we showed that a chymase-like enzyme is involved in this process when ECE and NEP are inhibited by phosphoramidon. Our results also suggest that ET-1(1-31) is an alternate intermediate in the production of ET-1 following BigET-1 administration. Finally, we showed that NEP is the predominant enzymatic pathway involved in the cleavage of ET-1(1-31) to a bioactive metabolite that will act on ET(A) receptors to induce contraction in the rabbit aorta.     

Antioxidants inhibit endothelin-1 (1-31)-induced proliferation of vascular smooth muscle cells via the inhibition of mitogen-activated protein (MAP) kinase and activator protein-1 (AP-1)

We previously found that human chymase cleaves big endothelins (ETs) at the Tyr(31)-Gly(32) bond and produces 31-amino acid ETs (1-31), without any further degradation products. In the present study, we investigated the effects of various antioxidants on the ET-1 (1-31)-induced change in intracellular signaling and proliferation of cultured rat aortic smooth muscle cells (RASMC). ET-1 (1-31) stimulated rapid and significant activation of the mitogen-activated protein (MAP) kinase family, i.e. extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun NH(2)-terminal kinase (JNK), and p38 MAPK, in RASMC to an extent similar to that of ET-1. All of the antioxidants examined, i.e. N-acetyl-L-cysteine (NAC), diphenyleneiodonium chloride (DPI), and L-(+)-ascorbic acid (ascorbic acid), inhibited both ET-1 (1-31)- and ET-1-induced JNK and p38 MAPK activation but not ERK1/2 activation. Electron paramagnetic resonance (EPR) spectroscopy measurements revealed that NAC, DPI, and ascorbic acid inhibited xanthine oxidase-induced superoxide (O(2)(.-)) generation in a cell-free system. ET-1 (1-31) in addition to ET-1 increased the generation of cellular reactive oxygen species (ROS) in RASMC. ET-1 (1-31)- and ET-1-induced cellular ROS generation was inhibited similarly by NAC, DPI, and ascorbic acid in RASMC. Gel-mobility shift analysis showed that ET-1 (1-31) and ET-1 caused an increase in activator protein-1 (AP-1)-DNA binding activity in RASMC that was inhibited by the above three antioxidants. ET-1 (1-31) increased [3H]thymidine incorporation into cells to an extent similar to that of ET-1. This ET-1 (1-31)-induced increase in [3H]thymidine incorporation was also inhibited by NAC and DPI, but not by ascorbic acid. These results suggest that antioxidants inhibit ET-1 (1-31)-induced RASMC proliferation by inhibiting ROS generation within the cells. The underlying mechanisms of the inhibition of cellular proliferation by antioxidants may be explained, in part, by the inhibition of JNK activation and the resultant inhibition of AP-1-DNA binding.     

Blood pressure responses of endothelin-1 1-31 within the rostral ventrolateral medulla through conversion to endothelin-1 1-21

Endothelin-1 1-31 (ET-1 1-31), a novel member of the endothelin family comprising 31 amino acids and derived from the selective hydrolysis of big ET-1 by chymase, directly activates endothelin receptors or converts to ET-1 1-21 by ET converting enzyme (ECE). The cardiovascular effects of central ET-1 1-31 are not identified. The present study was designed to investigate the cardiovascular actions of ET-1 1-31 within the rostral ventrolateral medulla (RVLM) in anesthetized rats. Bilateral injection of ET-1 1-31 (0.5, 1, and 2 pmol for each side) into the rostral ventrolateral medulla produced an initial pressor and/or a long-lasting hypotensive action but did not affect HR. Unilateral microinjection of 2 and 4 pmol of ET-1 1-31 into the rostral ventrolateral medulla only produced a significant (P < 0.05) transient increase in blood pressure by an average of 13 and 12 mm Hg, respectively, whereas unilateral microinjection of 8 pmol of ET-1 1-31 produced a sustained fall in blood pressure (from 92 +/- 6 to 69 +/- 8 mm Hg, P < 0.05). The transient pressor effect of unilaterally injecting ET-1 1-31 (4 pmol) into the rostral ventrolateral medulla was completely abolished by pretreatment with either ETA receptor antagonist BQ123 (83 +/- 2 versus 84 +/- 5 mm Hg, P > 0.05) or ET converting enzyme inhibitor phosphoramidon (99 +/- 5 versus 99 +/- 7 mm Hg, P > 0.05) but not ETB receptor antagonist IRL1038 (89 +/- 6 versus 96 +/- 7 mm Hg, P < 0.05). In addition, prior injection of phosphoramidon also completely abolished the long-lasting hypotension of intra-RVLM ET-1 1-31 (8 pmol) but did not modify the depressor action of intra-RVLM ET-1 1-21 (from 100 +/- 6 to 76 +/- 8 mm Hg, P < 0.05). In conclusion, the current results suggest that the cardiovascular effects of intra-RVLM ET-1 1-31 might be the result of conversion of ET-1 1-31 to ET-1 1-21 through activation of ETA receptors.     

Comparison of the effects of endothelin-1, -2 and -3 (1-31) on changes in [Ca2+]i in human coronary artery smooth muscle cells

We have previously found that human chymase selectively cleaves big endothelins (ETs) at the Tyr31-Gly32 bond to produce 31-amino-acid endothelins, ETs (1-31). In the present study, we investigated the effects of ETs (1-31) on changes in intracellular free Ca2+ ([Ca2+]i) in cultured human coronary artery smooth muscle cells (HCASMCs) using confocal laser microscopy. ETs (1-31) increased [Ca2+]i in a concentration-dependent manner. Phosphoramidon did not inhibit the increases in [Ca2+]i caused by ETs (1-31). The [Ca2+]i increases induced by ETs (1-31) were compared to those of ETs (1-21) and big ETs. ET-1 (1-21) was about 10-times more potent than big ET-1 or ET-1 (1-31), whereas big ET-2 was 10-times less potent than ET-2 (1-21) or ET-2 (1-31). ETs (1-31) may induce [Ca2+]i increase through ET(A)-type or ET(A)-type-like receptors. The 10(-12) M ET (1-31)-induced increases in [Ca2+]i were not affected by removal of extracellular Ca2+, but were inhibited by thapsigargin. These results suggested that ET-1, -2 and -3 (1-31) showed similar potencies in increasing [Ca2+]i and mechanisms of ET (1-31)-induced increases in [Ca2+]i may be similar among the three ETs (1-31).     

冬虫夏草对离体人肾小球系膜增殖的影响

目的 :观察冬虫夏草对离体人肾小球系膜增殖的疗效 ,并探讨其机制。方法 :利用体外培养的人肾小球系膜细胞 ,采用检测 3H胸腺嘧啶掺入量的方法 ,研究北冬虫夏草和天然冬虫夏草对低密度脂蛋白 (L DL )引起系膜细胞增殖的影响。结果 :2组冬虫夏草组的 3H掺入率均明显低于 L DL对照组 (P<0 .0 1) ,而 2组冬虫夏草之间同一浓度相比无显著性差异 (P>0 .0 5 )。结论 :冬虫夏草明显抑制 L DL引起的系膜细胞增殖 ,北冬虫夏草与天然冬虫夏草作用相似。其机制可能是由于冬虫夏草间接抑制了系膜细胞增殖过程中 DNA的合成。     

白花丹素抑制肾小球系膜细胞增殖及促纤维化相关因子的表达

目 的：探讨白花丹素对人肾小球系膜细胞株HMC细胞增殖及TGFβ1、CTGF、FN表达的影响。 方 法： 1 μmol/L~10 μmol/L白花丹素分别处理HMC细胞后,MTT法检测细胞增殖活性;RT-PCR和细胞免疫荧光法分别检测TGFβ1、CTGF、FN mRNA和蛋白的表达。 结 果：1 μmol/L~10 μmol/L白花丹素作用后,HMC细胞呈时间、浓度依赖性生长抑制,TGFβ1、CTGF、FN mRNA和蛋白的表达下降。 结 论： 白花丹素通过降低HMC细胞TGFβ1、CTGF、FN的表达,抑制HMC细胞增殖。     

肾小球系膜细胞增殖抑制的研究进展

肾小球系膜细胞异常增殖对肾小球疾病进展有重要作用,探讨其发生机制对肾小球疾病的防治具有重要意义.本文综述了近年来肾小球系膜细胞增殖机制及抑制因子的研究进展.     

益肾蠲湿合剂对肾小球系膜细胞增殖及细胞外基质分泌的影响

目的观察益肾蠲湿合剂对肾小球系膜细胞（GMC）增殖及细胞外基质的抑制作用。方法将含低、中、高剂量益肾蠲湿合剂的药物血清作用于10％血清-DMEM培养液培养的GMC,分别用噻唑蓝和酶联免疫吸附（ELISA）方法检测细胞增殖和培养液中基质的浓度。结果益肾蠲湿合剂对GMC增殖有明显的抑制作用,并随着剂量的增加作用也逐渐增强（72h低、中、高剂量的抑制率分别为28．3％、40．5％、47．5％）。同时益肾蠲湿合剂对GMC分泌细胞外基质有也明显的抑制作用（高剂量组对FN、LN及ColⅣ的抑制率分别为26．1％、25．4％、22．3％,中剂量组分别为17．4％、20．5％、15．9％;低剂量组分别为10．4％、10．7％、9．3％）。结论益肾蠲湿合剂对GMC的增殖及基质的分泌有明显的抑制作用,这可能是其有效抑制各种慢性肾炎发展的重要原因。     

他克莫司对人肾小球系膜细胞增殖的影响

目的探讨他克莫司对体外培养的人肾小球系膜细胞增殖的影响及可能机制。方法采用四甲基偶氮唑盐法(MTT)检测不同浓度的他克莫司处理后系膜细胞的增殖情况;用流式细胞仪检测不同浓度的他克莫司作用48、72h后系膜细胞细胞周期的改变;用流式细胞仪检测不同浓度的他克莫司作用72h后系膜细胞发生凋亡的情况。结果①浓度为1μmol/L的他克莫司对系膜细胞的增殖无明显抑制作用;作用24、48和72h后,浓度为5～20μmol/L的他克莫司能显著抑制系膜细胞的增殖;随着他克莫司浓度的增大,抑制作用更显著,呈一定的剂量—效应关系;随着他克莫司作用时间的延长,抑制作用更显著,呈一定的时间—效应关系。②5μmol/L的他克莫司作用48、72h,G0/G1期的系膜细胞百分比增高,S期的系膜细胞百分比降低,细胞周期阻滞于G0/G1期。③5μmol/L的他克莫司作用72h,对系膜细胞的凋亡无明显影响。结论他克莫司显著抑制体外培养的人肾小球系膜细胞增殖,且呈剂量和时间依赖性;其可能机制是使系膜细胞的细胞周期阻滞于G0/G1期。     

白细胞介素10对人系膜细胞增殖的调节

目的 观察白细胞介素10(IL—10)对体外培养的人肾小球系膜细胞(HMC)增殖影响。方法 分别应用^3H—胸腺嘧啶(^3H—TdR)和四甲基偶氮唑蓝(MTT)掺入法及流式细胞仪测定HMC增殖和细胞周期的变化。结果 血清可诱导系膜细胞明显增殖；IL—10则能呈剂量依赖性地抑制血清诱导的系膜细胞增殖，25ng／ml IL—10对系膜细胞增殖的抑制率接近70％；流式细胞仪分析表明IL—10可显减少S期和G2／M期细胞数。结论 IL—10通过下调血清诱导的人系膜细胞G0／G1期进入S期和G2／M期，从而达到抑制细胞增殖的目的，提示IL—10在增殖性肾小球肾炎中可能发挥重要的调节作用。     

体外转染Kiss-1基因对人黑色素瘤细胞A375生长增殖的影响

目的 探讨转染Kiss-1基因对人黑色素瘤细胞A375生长增殖的影响,筛选出有意义的肿瘤治疗的生物学靶标.方法 在人黑色素瘤细胞A375中转染Kiss-1基因,经G418筛选,建立稳定高表达Kiss-1蛋白的细胞系.Western blot方法 检测Kiss-1蛋白以证实转染成功.流式细胞术检测Kiss-1基因对A375生长增殖的影响.结果 稳定转染Kiss-1基因的A375细胞中不仅Kiss-1蛋白稳定表达（1.20±0.21）高于对照组（0.60±0.41）,Kiss-1基因转染A375细胞48 h后对其具有凋亡的作用（凋亡率为28.42%）高于对照组（2.12%）.结论 外源性Kiss-1基因导入A375细胞后,可诱导A375细胞其凋亡,从而抑制肿瘤细胞增殖.     

Effect of bradykinin on tyrosine kinase and phosphatase activities and cell proliferation in mesangial cells

We investigated the relationship between protein tyrosine phosphorylation and bradykinin (BK) receptor activation in rat mesangial cells (MC). Stimulation of the B2 receptor resulted in a dual effect consisting of an independent activation and inhibition of tyrosine kinase activity (TKA). The activation was rapid and transient, reaching a peak value at 30 s whereas the inhibition was observed at 5 min and persisted up to 10 min. Treatments with pertussis-toxin and U73122 showed that only the BK-induced stimulation of TKA is dependent on phospholipase C activation via a pertussis-toxin sensitive G-protein. In addition, BK induced an increase in tyrosine phosphatase activity. Western-blot analysis demonstrated that the dual effect of BK on TKA was associated with both an increase and a decrease in tyrosine phosphorylation of the p125-focal adhesion kinase (FAK). Moreover, BK was able to reduce the maximal stimulated MC cell proliferation induced by fetal calf serum. These data show that in rat MC, B2 receptor stimulation activates and inhibits two independent tyrosine kinase signaling pathways associated with tyrosine phosphorylation of p125-FAK that might be implicated in MC proliferation.     

血管紧张素-（1-7）对高糖诱导的大鼠肾小球系膜细胞表型转化的影响

目的观察血管紧张素-（1-7）[Ang-（1-7）]对高糖诱导的体外培养大鼠肾系膜细胞表型转化的影响。方法将35株体外培养的大鼠肾小球系膜细胞株EC（HB2Y-1）随机分为对照组9株,低糖组6株,高糖组7株,高糖＋Ang-（1-7）10-6mol/L组6株及高糖＋Ang-（1-7）10^-7mol/L组7株。采用免疫化学染色检测各组α-平滑肌肌动蛋白（α-SMA）的表达。结果高糖组细胞α-SMA表达明显高于对照组（P〈0.01）;与高糖组相比,高糖＋Ang-（1-7）10^-6mol/L组及高糖＋Ang-（1-7）10^-7mol/L组α-SMA阳性细胞率明显下降（P〈0.01）,但高糖＋Ang-（1-7）10^-7mol/L组下调幅度较低。结论Amg-（1-7）呈剂量依赖性抑制高糖诱导的体外培养大鼠肾系膜细胞表型转化。     

白细胞介素1β对人胃粘膜正常上皮细胞增殖的影响

目的研究白细胞介素1β（IL-1β）对人胃粘膜正常上皮细胞（GES-1）株增殖的影响。方法用IL广1β与GES-1细胞培养，用3^H-Tdr掺入法测定及MTT比色法分析检测总活细胞数来估计GES-1细胞DNA合成及细胞生成情况。结果IL-1β以剂量依赖性增加GES-1细胞DNA合成及细胞数量。IL-1β对GES-1细胞的增殖作用可被IL-1ra阻断，IL-1β抗体对此无抑制作用。结论IL-1β刺激可引起GES-1细胞的增殖。IL-1β是GES-1细胞的生长因子，在调节GES-1细胞增殖中有重要作用。IL-1β涉及幽门螺杆菌感染胃粘膜细胞的高增殖反应和胃癌的致癌过程。     

重组人内抑素对内皮细胞增殖的影响

目的　探讨原核表达的可溶性重组人内抑素(rhEndo)对ECV 30 4内皮细胞和原代培养兔主动脉内皮细胞增殖的影响。方法　利用酶标仪进行噻唑蓝 (MTT)法检测 ,同时采用倒置相差显微镜、电子显微镜、流式细胞仪、半胱天冬酶 3活性分析观察该内抑素对碱性成纤维细胞生长因子 (bFGF)刺激的血管内皮细胞增殖的影响。结果　该rhEndo明显抑制ECV 30 4细胞的增殖 ,MultiCycleDNACycle软件分析表明细胞增殖阻滞在G1期 ,流式细胞仪检测发现该内抑素可诱导ECV 30 4细胞凋亡 ,且与半胱天冬酶 3活性增强有关 ,但对原代培养的兔主动脉内皮细胞增殖并未产生明显的作用。结论　内抑素可明显抑制ECV 30 4细胞增殖并诱导其发生凋亡 ,但对原代培养的兔主动脉内皮细胞增殖没有明显的影响 ,这将有利于与血管新生有关的疾病如癌症等的治疗。     

维胺酯对皮肤鳞癌细胞系SCL-1增殖的影响

目的 探讨维胺酯对皮肤鳞癌细胞系SCL-1增殖的影响及可能机制.方法 MTT法检测不同浓度维胺酯(5、10、20、40、80 μmol/L)作用SCL-1细胞24、72 h后细胞增殖率.维胺酯10 μmol/L作用 SCL-1细胞24 h,流式细胞术检测细胞周期分布,实时荧光定量PCR检测维A酸受体(RAR)α、RAARβ、RARγ、维A酸X受体(RXR)α和他扎罗汀诱导基因1(TIG1)、细胞色素P450家族成员26A1 (CYP26A1) mRNA的表达;荧光素酶报告基因检测维胺酯10 μmol/L作用SCL-1细胞24 h激活蛋白1(AP-1)转录活性的变化.结果 5-80μmol/L的维胺酯呈时间和浓度依赖住地抑制SCL-1细胞.维胺酯10 μmol/L作用24 h后,SCL-1细胞的G1期百分比上升,而S期、G2期百分比下降.维胺酯10 μmol/L不诱导RARα、RARβ、RARγ、RXRα、TIG1和CYP26A1 mRNA的表达,但能在24 h内抑制AP-1的转录激活.结论 维胺酯抑制SCL-1细胞增殖涉及G1期细胞阻滞;其作用机制不依赖于经典的维A酸受体通路,而与抑制AP-1的转录活性有关.     

Modulation of cell proliferation and hypertrophy by gangliosides in cultured human glomerular mesangial cells

Glomerular mesangial cells (GMCs) in diverse renal diseases undergo cell proliferation and/or hypertrophy, and gangliosides have been reported to play an important role in modulating cell structure and function. This study compared the effects of transforming growth factor-beta1 (TGF-beta1) and the effects of the application of exogenous gangliosides on GMCs and investigated whether the application of exogenous gangliosides regulated cellular proliferation and hypertrophy. Human GMCs were cultured with exogenous gangliosides and TGF-beta1 in a media containing 10% fetal bovine serum and in a media without the fetal bovine serum. Exogenous gangliosides biphasically changed the proliferation of human GMCs (0.1-1.0 mg/mL). A low concentration (0.1 mg/mL) of gangliosides mainly increased the number of human GMCs, whereas cellular proliferation was significantly reduced by raising the concentration of exogenous gangliosides. TGF-beta1 greatly reduced the number of human GMCs in a concentration-dependent manner (1-10 ng/mL). Serum deprivation accelerated the gangliosides- and TGF-beta1-induced inhibition of mesangial cell proliferation to a greater extent. Gangliosides (1.0 mg/ mL) and TGF-beta1 (10 ng/mL) both caused a significant increase in the incorporation of [3H]leucine per cell in the serum-deprived condition, whereas it was completely reversed in serum-supplemented condition. Similar results to the [3H]leucine incorporation were also observed in the changes in cell size measured by flow cytometric analysis. These results show that exogenous gangliosides modulate cell proliferation and hypertrophy in cultured human GMCs, and these cellular responses were regulated differently based on whether the media contained serum or not. Results from the present study raise new possibilities about the potential involvement of gangliosides in the development of mesangial cell proliferation and hypertrophy.