吉圣珺,葉志堅(jiān),陳耀豐,劉劍,張培芳,鄭韶欣
(1.佛山市第一人民醫(yī)院呼吸內(nèi)科,廣東 佛山 528000;2.廣州市中山大學(xué)孫逸仙紀(jì)念醫(yī)院心內(nèi)科,廣東 廣州 510120)
·論 著·
TNF-α誘導(dǎo)人肺微血管內(nèi)皮細(xì)胞凋亡Caspase-3活性的研究
吉圣珺1,葉志堅(jiān)1,陳耀豐1,劉劍1,張培芳1,鄭韶欣2
(1.佛山市第一人民醫(yī)院呼吸內(nèi)科,廣東 佛山 528000;2.廣州市中山大學(xué)孫逸仙紀(jì)念醫(yī)院心內(nèi)科,廣東 廣州 510120)
目的 探討凋亡“核心蛋白酶”-半胱氨酸蛋白酶-3(Caspase-3)在腫瘤壞死因子-α(TNF-α)誘導(dǎo)人肺微血管內(nèi)皮細(xì)胞(HPMVECs)凋亡中的作用。方法體外培養(yǎng)HPMVECs,空白對(duì)照組置于CO2培養(yǎng)箱中常規(guī)培養(yǎng),TNF-α組分別以10 ng/mL、20 ng/mL、50 ng/mL、100 ng/mL濃度刺激HPMVECs,使用MTT比色法檢測(cè)各組細(xì)胞活性,AnnexinⅤ/PI雙染色聯(lián)合流式細(xì)胞術(shù)檢測(cè)細(xì)胞凋亡率,流式細(xì)胞術(shù)檢測(cè)Caspase-3的活性。結(jié)果空白對(duì)照組的細(xì)胞凋亡率及Caspase-3活性最低;空白對(duì)照組和TNF-α組(10 ng/mL、20 ng/mL、50 ng/mL)比較,100 ng/mL TNF-α組的相對(duì)細(xì)胞活性最低,而細(xì)胞凋亡率及Caspase-3活性最高,TNF-α誘導(dǎo)HPMVEC凋亡時(shí)呈現(xiàn)出濃度依賴性,隨著時(shí)間的延長(zhǎng),Caspase-3活性逐漸升高(P<0.05)。結(jié)論TNF-α誘導(dǎo)人肺微血管內(nèi)皮細(xì)胞凋亡呈現(xiàn)濃度依賴性,Caspase-3可能參與了這一細(xì)胞凋亡過(guò)程的調(diào)控。
腫瘤壞死因子-α;人肺微血管內(nèi)皮細(xì)胞;凋亡;半胱氨酸蛋白酶-3
慢性阻塞性肺疾病(Chronic obstructive pulmonary disease,COPD)是全世界范圍內(nèi)發(fā)病率和死亡率最高的疾病之一。肺動(dòng)脈高壓(Pulmonary hypertension,PH)是其常見(jiàn)的并發(fā)癥之一,PH的發(fā)生與COPD患者死亡率的顯著增加相關(guān)[1]。缺氧及炎癥引起肺血管收縮及重構(gòu)是慢性阻塞性肺疾病發(fā)生肺動(dòng)脈高壓的重要病理生理基礎(chǔ),肺血管內(nèi)皮損傷是PH發(fā)病的起始環(huán)節(jié),而血管內(nèi)皮細(xì)胞凋亡是血管內(nèi)皮損傷的重要機(jī)制[2-3]。半胱氨酸天冬氨酸蛋白水解酶(Caspase)家族是一組特異性切割天冬氨酸殘基上的肽鍵繼而引起細(xì)胞凋亡的蛋白水解酶,是所有凋亡蛋白中最主要的執(zhí)行者[4]。Caspase-3在血管內(nèi)皮細(xì)胞的凋亡信號(hào)傳導(dǎo)路徑中占據(jù)著的核心地位,是凋亡信號(hào)傳導(dǎo)的共同通路[5]。目前尚未見(jiàn)到有關(guān)于TNF-α誘導(dǎo)人肺微血管內(nèi)皮細(xì)胞(HPMVEC)凋亡與Caspase-3活性變化的相關(guān)報(bào)道。本研究探討了TNF-α誘導(dǎo)HPMVEC的凋亡及其可能的作用機(jī)制。
1.1 主要試劑及儀器 HPMVEC株購(gòu)自上海細(xì)胞庫(kù),100 mL/L胎牛血清及高糖細(xì)胞培養(yǎng)基購(gòu)自Hy-clone公司,四甲基偶氮唑藍(lán)購(gòu)自Sigma公司,Caspase-3活性檢測(cè)試劑盒、流式細(xì)胞儀購(gòu)自BD公司,異硫氰酸熒光素標(biāo)記的膜聯(lián)素Ⅴ/碘化丙啶(AnnexinⅤ-fluorescein isothiocyanate/propidium iodide,AnnexinⅤ-FITC/PI)凋亡檢測(cè)試劑盒購(gòu)自瑞士Roche公司。
1.2 HPMVEC的復(fù)蘇和傳代培養(yǎng) 從液氮保存罐中取出凍存管(含原代HPMVEC),立即放入37℃水浴中,快速搖晃,直至凍存液完全融化。將其置于含100 mL/L胎牛血清的DMEM培養(yǎng)液中,在37℃、50 mL/L CO2培養(yǎng)箱中培養(yǎng),隔天換液。內(nèi)皮細(xì)胞呈鵝卵石樣貼壁生長(zhǎng),當(dāng)細(xì)胞生長(zhǎng)至90%匯合時(shí)用2.5 g/L乙二胺四乙酸(Ethylene diamine tetraacetic acid,EDTA)胰蛋白酶進(jìn)行消化傳代,取第4代血管內(nèi)皮細(xì)胞進(jìn)行實(shí)驗(yàn)。
1.3 實(shí)驗(yàn)分組及處理 空白對(duì)照組:用100 mL/L胎牛血清的DMEM培養(yǎng)基處理內(nèi)皮細(xì)胞,置于50 mL/L CO2培養(yǎng)箱中常規(guī)培養(yǎng);TNF-α組:分別用10 ng/mL、20 ng/mL、50 ng/mL、100 ng/mL TNF-α進(jìn)行刺激,然后用100 mL/L胎牛血清的DMEM培養(yǎng)基處理內(nèi)皮細(xì)胞,置于50 mL/L CO2培養(yǎng)箱中常規(guī)培養(yǎng)。
1.4 MTT法檢測(cè)HPMVEC的增殖活性 MTT比色法測(cè)定各組細(xì)胞的活性。收集對(duì)數(shù)期細(xì)胞,調(diào)整細(xì)胞數(shù);以4 000個(gè)/孔細(xì)胞接種到96孔板中。37℃、50 mL/L CO2條件下孵育1 d;棄去培養(yǎng)液,按上述實(shí)驗(yàn)分組方法處理細(xì)胞。吸干培養(yǎng)基,每孔加入20 μL MTT溶液,繼續(xù)孵育4 h,終止培養(yǎng)。小心吸棄孔內(nèi)培養(yǎng)上清液,每孔加入150 μL DMSO溶液,置搖床上低度振蕩10 min,用酶標(biāo)儀檢測(cè)490 nm波長(zhǎng)各孔的吸光度(A)值。細(xì)胞活力=(A處理組-A空白管)/(A空白對(duì)照組-A空白管)× 100%。
1.5 AnnexinⅤ/PI雙染色聯(lián)合流式細(xì)胞術(shù)檢測(cè)HPMVEC的凋亡 細(xì)胞分為空白對(duì)照組、TNF-α處理組。每組取3個(gè)6孔板的培養(yǎng)孔,胰蛋白酶消化(不含EDTA)收集細(xì)胞,1 000×g離心5 min,棄上清。磷酸鹽緩沖液(PBS)重懸細(xì)胞后,離心,重復(fù)兩次后棄上清。分別加入結(jié)合緩沖液200 μL重懸并進(jìn)行細(xì)胞計(jì)數(shù),調(diào)整細(xì)胞數(shù)。取200 μL細(xì)胞懸液,加入5 μL annexinⅤ-FITC混勻,室溫避光10 min。再加入5 μL PI染液混勻,流式細(xì)胞儀進(jìn)行檢測(cè)分析:每份樣品取1×104個(gè)細(xì)胞PI染色,做DNA分析。
1.6 Caspase-3的活性檢測(cè) 根據(jù)預(yù)實(shí)驗(yàn)結(jié)果,實(shí)驗(yàn)分為空白對(duì)照組、TNF-α處理組。分別收集各組細(xì)胞。1 500 r/min離心10 min,用預(yù)冷的PBS洗滌細(xì)胞兩次;4℃、300×g離心5 min,收集(1~5)×105個(gè)細(xì)胞;加氟甲基酮標(biāo)記的轉(zhuǎn)錄因子2-天冬氨酸-谷氨酸-纈氨酸-天冬氨酸(Transcription factor 2-Asp-Glu-Val-A sp-fluoromethylketone,TF2-DEVD-FMK),37℃反應(yīng)1 h;流式細(xì)胞術(shù)分析Caspase-3陽(yáng)性細(xì)胞數(shù)和平均熒光強(qiáng)度[6-7]。
1.7 統(tǒng)計(jì)學(xué)方法 應(yīng)用SPSS17.0統(tǒng)計(jì)學(xué)軟件進(jìn)行數(shù)據(jù)分析,計(jì)量資料以均數(shù)±標(biāo)準(zhǔn)差(±s)表示,多組比較采用單因素方差分析,組間比較采用t檢驗(yàn),以P<0.05為差異有統(tǒng)計(jì)學(xué)意義。
2.1 MTT比色法檢測(cè)細(xì)胞活性 10 ng/mL、20 ng/mL、50 ng/mLTNF-α處理組與100 ng/mLTNF-α處理組間差異有統(tǒng)計(jì)學(xué)意義(P<0.05),而100 ng/mL TNF-α處理組的相對(duì)細(xì)胞活性明顯低于空白對(duì)照組(P<0.01),TNF-α對(duì)細(xì)胞活性的抑制與TNF-α劑量呈現(xiàn)劑量依賴關(guān)系,見(jiàn)表1。
組別空白對(duì)照組TNF-α處理組10 ng/mL 20 ng/mL 50 ng/mL 100 ng/mL OD值1.97±0.05相對(duì)細(xì)胞活性(%) 100±0.00 1.84±0.01 1.81±0.02a1.71±0.02a1.53±0.02abcd93.68±3.30 92.24±2.55a87.30±2.64a77.93±2.97abcd
2.2 AnnexinⅤ/PI檢測(cè)HPMVEC凋亡 10 ng/mL、20 ng/mL、50 ng/mL TNF-α處理組與空白對(duì)照組間差異均有統(tǒng)計(jì)學(xué)意義(P<0.05),而100 ng/mL TNF-α處理組的細(xì)胞凋亡率最高(P<0.01),TNF-α對(duì)細(xì)胞活性的抑制與TNF-α劑量呈現(xiàn)劑量依賴關(guān)系,見(jiàn)表2。
表2 不同劑量TNF-α刺激下HPMVEC的凋亡率檢測(cè)(n=3,±s)
表2 不同劑量TNF-α刺激下HPMVEC的凋亡率檢測(cè)(n=3,±s)
組別空白對(duì)照組TNF-α處理組10 ng/mL 20 ng/mL 50 ng/mL 100 ng/mL細(xì)胞凋亡率(%) 0.00±0.005 5.57±0.23a6.69±0.17ab8.67±0.25abc10.76±0.25abcd
2.3 HPMVEC的Caspase-3活性檢測(cè) 10 ng/mL、20 ng/mL、50 ng/mL TNF-α處理組與空白對(duì)照組間差異有統(tǒng)計(jì)學(xué)意義(t值分別為43.85、96.24、26.45,P值分別為0.000 5、0.000 1、0.001,P<0.05),而100 ng/mL TNF-α處理組的Caspase-3活性最高(t=16.77,P= 0.004),隨著時(shí)間的延長(zhǎng),Caspase-3活性逐漸升高,與空白對(duì)照組比較,100 ng/mL TNF-α組在24 h時(shí)Caspase-3的活性最高(t=62.06,P=0.003),見(jiàn)表3。
表3 不同劑量TNF-α刺激下HPMVEC的Caspase-3活性檢測(cè)(n=3,±s)
表3 不同劑量TNF-α刺激下HPMVEC的Caspase-3活性檢測(cè)(n=3,±s)
注:與空白對(duì)照組比較,aP<0.05;與10 ng/mL TNF-α組比較,bP<0.05;與20 ng/mL TNF-α組比較,cP<0.05;與50 ng/mL TNF-α組比較,dP<0.05;與0 h組比較,eP<0.05;與6 h組比較,fP<0.05;與12 h組比較,gP<0.05。
組別Caspase-3活性(%) 0 h 6 h 12 h 24 h空白對(duì)照組TNF-α處理組10 ng/mL 20 ng/mL 50 ng/mL 100 ng/mL 0.39±0.184.98±0.585.79±0.386.03±0.38 15.36±0.92aefg17.37±0.92aefg24.56±0.77abcefg25.39±0.59abcdef5.2±0.33a5.98±0.16a8.12±0.47abc11.33±1.00abcd9.2±0.56ae10.52±0.82ae13.39±1.00abce16.65±0.72abcde10.97±0.97ae14.05±0.55abef16.85±0.85abcef23.60±0.80abcdef
COPD是常見(jiàn)的呼吸系統(tǒng)疾病,其發(fā)病率及病死率呈現(xiàn)逐年增加的趨勢(shì),目前已成為全球第四大致死性病因[8]。PH是其重要的合并癥,炎癥反應(yīng)是COPD患者形成PH的重要因素[9],炎癥引起的血管內(nèi)皮細(xì)胞凋亡是PH發(fā)生的重要機(jī)制[10]。近年來(lái),有關(guān)于血管內(nèi)皮細(xì)胞凋亡與PH之間的研究逐漸增多[11-13]。
本實(shí)驗(yàn)發(fā)現(xiàn),10 ng/mL的TNF-α即可引起HPMVEC發(fā)生凋亡,隨著TNF-α濃度的增加,HPMVEC凋亡率亦增加;100 ng/mL的TNF-α作用于HPMVEC時(shí),細(xì)胞凋亡率最高,TNF-α對(duì)細(xì)胞活性的抑制與TNF-α劑量呈現(xiàn)出劑量依賴關(guān)系。Chen等[14]研究也支持本實(shí)驗(yàn)的結(jié)果。Kim等[15]發(fā)現(xiàn),細(xì)胞凋亡的增加與Caspase-3的表達(dá)增強(qiáng)相關(guān)。
筆者進(jìn)一步探討了TNF-α誘導(dǎo)HPMVEC凋亡的分子機(jī)制。目前研究發(fā)現(xiàn),血管內(nèi)皮細(xì)胞凋亡主要有兩條信號(hào)轉(zhuǎn)導(dǎo)通路,分別由Caspase-8激活的外源性途徑即死亡受體途徑及Caspase-9激活的細(xì)胞內(nèi)在途徑即線粒體通路,而兩者最終均需要通過(guò)激活Caspase-3來(lái)實(shí)現(xiàn),因此,目前認(rèn)為,Caspase-3是血管內(nèi)皮細(xì)胞發(fā)生凋亡的標(biāo)志物。本實(shí)驗(yàn)結(jié)果發(fā)現(xiàn),隨著TNF-α作用濃度的增加及時(shí)間的延長(zhǎng),Caspase-3的活性表達(dá)亦隨之增強(qiáng),Caspase-3的活性表達(dá)與HPMVEC凋亡率的增加呈正相關(guān)關(guān)系。與Ohtsubo等[16]研究結(jié)果相符合。有關(guān)于血管內(nèi)皮細(xì)胞凋亡信號(hào)通路的探討是近年來(lái)PH的研究熱點(diǎn),除了 Caspase-3通路,還包括 PI3K/AKT[17]、P38MAPK[18]及STAT3[19-20]等通路途徑。在未來(lái)的研究中,我們將進(jìn)一步探討Caspase-3的上游信號(hào)通路,進(jìn)一步了解TNF-α誘導(dǎo)HPMVEC凋亡的完整信號(hào)分子傳導(dǎo)途徑。
綜上所述,筆者認(rèn)為TNF-α可誘導(dǎo)HPMVEC發(fā)生凋亡,并且這一凋亡作用呈現(xiàn)濃度依賴性。而在細(xì)胞凋亡過(guò)程中,Caspase-3的活性表達(dá)增強(qiáng),因此,TNF-α誘導(dǎo)HPMVEC凋亡可能與上調(diào)Caspase-3的活性表達(dá)有關(guān)。
[1]Hayes D Jr,Black SM,Tobias JD,et al.Prevalence of pulmonary hypertension and its influence on survival in patients with advanced chronic obstructive pulmonary disease prior to lung transplantation [J].COPD,2016,13(1):50-56.
[2]Li S,Xu J,Yao W,et al.Sevoflurane pretreatment attenuates TNF-α-induced human endothelial cell dysfunction through activating eNOS/ NO pathway[J].Biochem Biophys Res Commun,2015,460(3): 879-886.
[3]Yamaji-Kegan K,Takimoto E,Zhang A,et al.Hypoxia-induced mitogenic factor(FIZZ1/RELMα)induces endothelial cell apoptosis and subsequent interleukin-4-dependent pulmonary hypertension[J]. Am J Physiol Lung Cell Mol Physiol,2014,306(12):L1090-L1103.
[4] Choudhary GS,Al-Harbi S,Almasan A.Caspase-3 activation is a critical determinant of genotoxic stress-induced apoptosis[M].New York:Methods Mol Biol,2015:1-9.
[5]吳云飛,鄭維銀,李焰.Caspase-3在血管內(nèi)皮細(xì)胞凋亡中的作用研究進(jìn)展[J].西南軍醫(yī),2013,15(4):408-411.
[6]馮永東,陶德定,謝大興,等.流式細(xì)胞術(shù)檢測(cè)胱氡肽酶3原位激活與兩種檢測(cè)細(xì)胞凋亡方法的比較性研究[J].中華檢驗(yàn)醫(yī)學(xué)雜志, 2004,27(9):582-585.
[7] Porter AG,J?nicke RU.Emerging roles of Caspase-3 in apoptosis [J].Cell Death Differ,1999,6(2):99-104.
[8] Vijayan VK.Chronic obstructive pulmonary disease[J].Indian J Med Res,2013,137(2):251-269.
[9]李雪英.慢性阻塞性肺病相關(guān)肺動(dòng)脈高壓與炎癥反應(yīng)[J].臨床肺科雜志,2014,19(5):900-902.
[10]Sage E,Mercier O,Van den Eyden F,et al.Endothelial cell apoptosis in chronically obstructed and reperfused pulmonary artery[J].Respiratory Research,2008,9:19.
[11]Tian W,Jiang X,Tamosiuniene R,et al.Blocking macrophage leukotriene b4 prevents endothelial injury and reverses pulmonary hypertension[J].Sci Transl Med,2013,5(200):2418-2419.
[12]Cao Y,Jiang Z,Zeng Z,et al.Bcl-2 silencing attenuates hypoxia-induced apoptosis resistance in pulmonary microvascular endothelial cells[J].Apoptosis,2016,21(1):69-84.
[13]Liu P,Zhang HM,Tang YJ,et al.Influence of Rho kinase inhibitor fasudil on late endothelial progenitor cells in peripheral blood of COPD patients with pulmonary artery hypertension[J].Bratisl Lek Listy,2015,116(3):150-153.
[14]Chen TG,Zhong ZY,Sun GF,et al.Effects of tumour necrosis factor-alpha on activity and nitric oxide synthase of endothelial progenitor cells from peripheral blood[J].Cell Prolif,2011,44(4): 352-359.
[15]Kim KC,Lee JC,Lee H,et al.Changes in Caspase-3,B cell leukemia/lymphoma-2,interleukin-6,tumor necrosis factor-α and vascular endothelial growth factor gene expression after human umbilical cord blood derived mesenchymal stem cells transfusion in pulmonary hypertension rat models[J].Korean Circ J,2016,46(1): 79-92.
[16]Ohtsubo H,Ichiki T,Imayama I,et al.Involvement of Mst1 in tumor necrosis factor-alpha-induced apoptosis of endothelial cells[J/OL].Biochem Biophys Res Commun,2008,367(2):474-480.
[17]Wang J,Chen Y,Yang Y,et al.Endothelial progenitor cells and neural progenitor cells synergistically protect cerebral endothelial cells from Hypoxia/reoxygenation-induced injury via activating the PI3K/Akt pathway[J].Mol Brain,2016,9(1):1-12.
[18]曾海龍,黃志秋,張藝能,等.p38MAPK/eNOS信號(hào)通道在胰高血糖素樣肽-1抑制AGEs誘導(dǎo)的人臍靜脈內(nèi)皮細(xì)胞凋亡中的作用[J].南方醫(yī)科大學(xué)學(xué)報(bào),2016,36(1):116-119.
[19]Bader AM,Brodarac A,Klose K,et al.Cord blood mesenchymal stromal cell-conditioned medium protects endothelial cells via STAT3 signaling[J].Cell Physiol Biochem,2014,34(3):646-657.
[20]Zhang S,Patel A,Moorthy B,et al.Adrenomedullin deficiency potentiates hyperoxic injury in fetal human pulmonary microvascularendothelial cells[J].Biochem Biophys Res Commun,2015,464(4): 1048-1053.
Caspase-3 activity in TNF-α-induced apoptosis of human pulmonary microvascular endothelial cells.
JI Sheng-jun1,YE Zhi-jian1,CHEN Yao-feng1,LIU Jian1,ZHANG Pei-fang1,ZHENG Shao-xin2.1.Department of Respiratory Medicine,the First People's Hospital of Foshan,Foshan 528000,Guangdong,CHINA;2.Department of Cardiology,Sun Yat-sen Memorial Hospital of the Sun Yat-sen University,Guangzhou 510120,Guangdong,CHINA
ObjectiveTo investigate the change of Caspase-3 activity in tumor necrosis factor-α(TNF-α)induced apoptosis of human pulmonary microvascular endothelial cells(HPMVECs).MethodsHPMVECs were cultured in vitro.The blank control was treated in a carbon dioxide incubator.HPMVECs were treated by TNF-α at the concentration of 10 ng/mL,20 ng/mL,50 ng/mL,or 100 ng/mL.The activity of cells,apoptosis rate,as well as the expressions of Caspase-3 in HPMVECs were determined respectively by MTT cell viability assay,flow cytometric analysis with dual Annexin V-FITC/propidium iodide(PI)staining and flow cytometry.ResultsApoptosis rate of cell and Caspase-3 activity were the lowest in the blank control group.Compared with the other groups(10 ng/mL,20 ng/mL,50 ng/mL),the Caspase-3 activity and apoptosis rate of cell in 100 ng/mL TNF-α group were highest,and with the lowest cell activity. The inhibition of TNF-α-induced cell activity was a manner of dose-dependent.The Caspase-3 activity increased gradually with time(P<0.05).ConclusionTNF-α-induced apoptosis of HPMVEC is a manner of dose-dependent,and Caspase-3 may be taking part in the control of apoptosis process.
Tumor necrosis factor-α(TNF-α);Human pulmonary microvascular endothelial cells(HPMVECs);Apoptosis;Caspase-3
R329.2+7
A
1003—6350(2016)14—2237—04
2016-02-23)
國(guó)家自然科學(xué)基金(編號(hào):81400251);廣東省佛山市衛(wèi)生及計(jì)生局醫(yī)學(xué)科研立項(xiàng)課題(編號(hào):2015255)
鄭韶欣。E-mail:schwannnn@163.com