郭道宇 劉昊 李冬
【摘要】 目的:研究依達(dá)拉奉防護(hù)過氧化氫(H2O2)損傷神經(jīng)細(xì)胞PC12的分子機(jī)制,為依達(dá)拉奉在腦出血疾病的治療利用提供理論依據(jù)。方法:本研究設(shè)置對照組(PC12細(xì)胞)、損傷組[PC12細(xì)胞+H2O2(600 μmol/L)]和處理組[PC12細(xì)胞+H2O2(600 μmol/L)+依達(dá)拉奉(0.5 mmol/L)]。觀察依達(dá)拉奉對PC12細(xì)胞氧化損傷防護(hù)效果。結(jié)果:損傷組PC12細(xì)胞繁殖下降,而處理組細(xì)胞數(shù)量接近對照組。細(xì)胞流式實(shí)驗(yàn)顯示:處理組PC12細(xì)胞沒有發(fā)生明顯的凋亡,而損傷組細(xì)胞凋亡率稍高。與對照組比較,損傷組細(xì)胞內(nèi)ROS的熒光強(qiáng)度顯著升高,損傷組細(xì)胞培養(yǎng)上清液中SOD、GSH-Px活性均顯著降低,而MDA含量顯著升高(P<0.05)。與損傷組比較,處理組細(xì)胞內(nèi)ROS的熒光強(qiáng)度顯著降低,處理組細(xì)胞培養(yǎng)上清液中SOD、GSH-Px的活性均顯著提高,MDA水平顯著降低(P<0.05)。Western blot實(shí)驗(yàn)分析結(jié)果顯示:處理組中ATG7表達(dá)顯著增強(qiáng),同時(shí),LC3Ⅰ含量減少,而LC3Ⅱ含量增加。結(jié)合KEGG富集分析發(fā)現(xiàn):在損傷組和對照組間,有4條信號通路發(fā)生了顯著性變化,其中mTOR信號通路和Caspase介導(dǎo)的信號通路被激活;在處理組和對照組間,有12條信號通路發(fā)生了顯著性變化,其中mTOR信號通路和MAPK信號通路被激活,而與細(xì)胞凋亡密切相關(guān)的Caspase信號通路沒有顯著增強(qiáng)。結(jié)論:依達(dá)拉奉通過增強(qiáng)PC12細(xì)胞自噬而防護(hù)氧損傷。該研究為依達(dá)拉奉在氧損傷對神經(jīng)元細(xì)胞保護(hù)機(jī)制的研究提供了一定的理論參考。
【關(guān)鍵詞】 PC12細(xì)胞 依達(dá)拉奉 H2O2脅迫 自噬 轉(zhuǎn)錄組學(xué)
Study on the Mechanism of Edaravone Enhancing Autophagy Protection in PC12 Cells from Oxidative Injury/GUO Daoyu, LIU Hao, LI Dong. //Medical Innovation of China, 2021, 18(36): 0-030
[Abstract] Objective: To study the molecular mechanism of Edaravone protecting nerve cell PC12 from hydrogen peroxide (H2O2) injury, so as to provide a theoretical basis for the treatment and utilization of edaravone in intracerebral hemorrhage. Method: In this study, the control group (PC12 cells) and the injury group [PC12 cells + H2O2 (600 μmol/L)] and treatment group [PC12 cells + H2O2 (600 μmol/L) + Edaravone (0.5 mmol/L)]. The protective effect of Edaravone on oxidative damage of PC12 cells was observed. Result: The proliferation of PC12 cells in the injury group decreased, while the number of cells in the treatment group was close to that in the control group. Flow cytometry showed that there was no obvious apoptosis in PC12 cells in the treatment group, but the apoptosis rate in the injury group was slightly higher. Compared with the control group, the fluorescence intensity of ROS in the injured group increased significantly, the activities of SOD and GSH-Px in the cell culture supernatant decreased significantly, and the content of MDA increased significantly (P<0.05). Compared with the injury group, the fluorescence intensity of ROS in the treatment group decreased significantly, the activities of SOD and GSH-Px in the cell culture supernatant in the treatment group increased significantly, and the level of MDA decreased significantly (P<0.05). The results of Western blot analysis showed that the expression of ATG7 was significantly increased in the treatment group, while the content of LC3Ⅰ decreased and the content of LC3Ⅱ increased. Combined with KEGG enrichment analysis, it was found that there were significant changes in four signal pathways between the injury group and the control group, in which mTOR signal pathway and caspase mediated signal pathway were activated; There were significant changes in 12 signal pathways between the treatment group and the control group, in which mTOR signal pathway and MAPK signal pathway were activated, but caspase signal pathway closely related to apoptosis was not significantly enhanced. Conclusion: Edaravone protects PC12 cells from oxygen injury by enhancing autophagy. This study provides a theoretical basis for the action of edaravone protection of neurons from oxygen-induced injury.
[Key words] PC12 cells Edaravone H2O2 stress Autophagy Transcriptomics
First-author’s address: North China University of Science and Technology Affiliated Hospital, Hebei Province, Tangshan 063009, China
doi:10.3969/j.issn.1674-4985.2021.36.007
腦出血(intracerebral hemorrhage,ICH)是由血管壁病變或腦血管導(dǎo)致顱內(nèi)血液凝結(jié)功能障礙或血液動力學(xué)改變的一種非創(chuàng)傷性的腦實(shí)質(zhì)出血[1]。腦出血可引起多種類型的神經(jīng)元損傷,氧化應(yīng)激損傷是其中之一[2]。大腦細(xì)胞中含有豐富的脂質(zhì)且抗氧化能力較弱,因此很容易成為氧化應(yīng)激損傷的靶點(diǎn)[3-4],因此,腦出血后神經(jīng)元細(xì)胞凋亡、死亡、自噬等都與氧化應(yīng)激損傷后過度出現(xiàn)的自由基和ROS有關(guān)[5-6],這些自由基和ROS等的過度化打破了神經(jīng)元細(xì)胞抗氧化防御機(jī)制的最強(qiáng)能力,從而導(dǎo)致細(xì)胞發(fā)生損傷[7]。
先前研究表明在氧化應(yīng)激的狀態(tài)下,Keap1/Nrf2復(fù)合物中解離下的轉(zhuǎn)錄因子Nrf2進(jìn)入細(xì)胞核,結(jié)合在抗氧化反應(yīng)元件(ARE)上激活許多抗氧化酶[8-9]。而腦保護(hù)劑依達(dá)拉奉,一種自由基清除劑[10],可以有效提高Nrf2的表達(dá)從而抑制氧化應(yīng)激對神經(jīng)元細(xì)胞的損傷[8]。但是Nrf2基因是怎樣被依達(dá)拉奉增強(qiáng)轉(zhuǎn)錄的機(jī)制尚不清楚,本研究構(gòu)建腦出血后氧化應(yīng)激神經(jīng)細(xì)胞模型(H2O2脅迫PC12細(xì)胞),通過RNA-seq技術(shù)深入解析依達(dá)拉奉對神經(jīng)細(xì)胞的保護(hù)作用。現(xiàn)報(bào)道如下。
1 材料與方法
1.1 試劑與儀器 依達(dá)拉奉( Edaravone,Mitsubishi Chemical Corporation,日本),DMEM培養(yǎng)基,胎牛血清(Gibco,美國),超凈工作臺(蘇州凈化),CO2培養(yǎng)箱(ESCO),高速低溫離心機(jī),全波長酶標(biāo)儀(SPECTROstar Nano),流式細(xì)胞儀(伯樂S6e)等。蛋白提取試劑(碧云天生物科技有限公司),MDA和SOD活性檢測試劑盒(北京索萊寶生物科技有限公司)、Western blot抗體(Abcam)、RNA-seq實(shí)驗(yàn)(上海生工生物工程有限公司)。
1.2 細(xì)胞分組與處理 本實(shí)驗(yàn)所用PC12細(xì)胞購自中國科學(xué)院典型培養(yǎng)物保藏委員會細(xì)胞庫,然后齊魯醫(yī)藥學(xué)院保存。本實(shí)驗(yàn)中將PC12細(xì)胞分為對照組、損傷組和處理組,每組5個(gè)重復(fù),對照組采用DMEM培養(yǎng)基培養(yǎng),損傷組在培養(yǎng)基中加入H2O2(終濃度為600 μmol/L)[11],處理組在培養(yǎng)基中加入終濃度為600 μmol/L的H2O2后12 h,加入依達(dá)拉奉注射液(終濃度為0.5 mmol/L)[12]。將三組細(xì)胞置于37 ℃,5% CO2培養(yǎng)箱孵育24 h。
1.3 細(xì)胞存活率檢測 將三組PC12細(xì)胞以1×103個(gè)/孔的細(xì)胞量接種于96孔板,37 ℃、5% CO2培養(yǎng)箱中培養(yǎng)24 h,然后每孔加入MTT(5 mg/mL),37 ℃繼續(xù)孵育4 h。去掉培養(yǎng)基,用PBS緩沖液清洗一次,去掉PBS后再每孔加入100 μL二甲基亞砜(dimethyl sulfoxide,DMSO)溶解甲瓚晶體。待結(jié)晶完全溶解后,吸棄DMSO,用PBS緩沖液清洗3遍后,加入100 μL PBS緩沖液,置于酶標(biāo)儀中測定波長490 nm處吸光值。
1.4 細(xì)胞凋亡檢測 將三組細(xì)胞以1×106個(gè)/孔的細(xì)胞量接種至6孔板中,37 ℃、5% CO2孵箱中孵育培養(yǎng)72 h,胰酶消化后,用Annexin V-FITC和Propidium Iodide(PI)雙染法在流式細(xì)胞儀上進(jìn)行細(xì)胞凋亡檢測并進(jìn)行數(shù)據(jù)分析。
1.5 細(xì)胞氧化應(yīng)激水平檢測 PC12細(xì)胞被藥物處理后,加入0.5%的胰酶消化細(xì)胞,收集細(xì)胞到15 mL離心管,4 ℃ 1 000 r/min離心沉淀細(xì)胞,吸取并保存上清液。將上清液與熒光探針DCFH-DA 1 mmol/L在室溫孵育30 min,然后用酶標(biāo)儀檢測熒光強(qiáng)度。根據(jù)熒光強(qiáng)度及試劑盒說明書上的計(jì)算方法評估細(xì)胞上清液中MDA含量和SOD活性。
1.6 Western blot檢測細(xì)胞自噬相關(guān)蛋白 取處理后的細(xì)胞樣品裂解提取總蛋白,并用Qubit 3.0熒光儀測定蛋白濃度。取20 μg總蛋白進(jìn)行10%的SDS-PAGE電泳,然后進(jìn)行轉(zhuǎn)膜至PVDC膜。用5%脫脂牛奶室溫封閉蛋白2 h,隨后加入一抗(ATG7 1︰500,LC3Ⅱ 1︰1 000,LC3Ⅰ 1︰500,Actin 1︰1 000)置于4 ℃環(huán)境進(jìn)行過夜封閉,第2天加入對應(yīng)二抗(1︰2 000)室溫封閉1 h,最后滴加ECL。以Actin作為內(nèi)參,在暗室壓片曝光分析。
1.7 轉(zhuǎn)錄組基因富集分析 取處理后的細(xì)胞樣品提交給Beyotime生物技術(shù)公司進(jìn)行RNA-seq。使用Qubit? 3.0熒光儀(Invitrogen)對RNA定量后,上機(jī)RNA樣品按照QuantSeq 3’mRNA-Seq文庫試劑盒FWD(illumina)說明進(jìn)行處理,然后使用NextSeq 500測序系統(tǒng)(illumina)進(jìn)行分析。數(shù)據(jù)FASTQ文件被上傳到隨機(jī)軟件BaseSpace進(jìn)行分析[13]。使用BaseSpace軟件中的Cufflinks Assembly和DE application (Version 2.1.0)對輸出文件進(jìn)行分析,以確定差異表達(dá)基因(DEGs),這些差異表達(dá)基因用于生成表達(dá)熱圖和FPKM散點(diǎn)圖。此外,數(shù)據(jù)基因的分析還使用ClueGO(2.3.3版)、CluePedia(1.3.3版)、Cytoscape(3.5.1版)等軟件。生物過程(BPs)的功能分組是基于Kappa評分進(jìn)行的。下載基因本體數(shù)據(jù)進(jìn)行分析。基因集富集分析(3.0版)用于測定實(shí)驗(yàn)組中差異富集的BPs[14]。
1.8 統(tǒng)計(jì)學(xué)處理 采用SPSS 18.0 (SPSS Inc.,Chicago,IL,USA)軟件對所得數(shù)據(jù)進(jìn)行統(tǒng)計(jì)分析,計(jì)量資料用(x±s)表示,比較采用t檢驗(yàn);計(jì)數(shù)資料以率(%)表示,比較采用字2檢驗(yàn)。以P<0.05為差異有統(tǒng)計(jì)學(xué)意義。
2 結(jié)果
2.1 依達(dá)拉奉對PC12細(xì)胞氧化損傷防護(hù)效
果 對照組吸光值為(0.80±0.03),損傷組吸光值為(0.31±0.02),處理組吸光值為(0.69±0.04)。損傷組PC12細(xì)胞繁殖下降,可能是因?yàn)镠2O2引起細(xì)胞死亡或凋亡,而處理組細(xì)胞數(shù)量接近對照組,見圖1A。細(xì)胞流式實(shí)驗(yàn)顯示:處理組PC12細(xì)胞沒有發(fā)生明顯的凋亡,而損傷組細(xì)胞凋亡率稍高,見圖1B、1C、1D。
注:A示MTT實(shí)驗(yàn)檢測H2O2脅迫下PC12細(xì)胞的存活率;B示對照組流式細(xì)胞分析情況;C示損傷組流式細(xì)胞分析情況;D示處理組流式細(xì)胞分析情況。
2.2 PC12細(xì)胞中依達(dá)拉奉拮抗氧化應(yīng)激變化情況 與對照組比較,損傷組細(xì)胞內(nèi)ROS的熒光強(qiáng)度顯著升高,損傷組細(xì)胞培養(yǎng)上清液中SOD、GSH-Px活性均顯著降低,而MDA含量顯著升高(P<0.05)。與損傷組比較,處理組細(xì)胞內(nèi)ROS的熒光強(qiáng)度顯著降低,處理組細(xì)胞培養(yǎng)上清液中SOD、GSH-Px的活性均顯著提高,MDA水平顯著降低(P<0.05)。見表1。
2.3 依達(dá)拉奉促進(jìn)PC12細(xì)胞自噬情況 通過Western blot實(shí)驗(yàn)分析依達(dá)拉奉對PC12細(xì)胞的防護(hù)作用,對每條條帶灰度值采用ImageJ軟件分析,以actin蛋白灰度值為基準(zhǔn),計(jì)算各蛋白的相對表達(dá),對照組ATG7表達(dá)量為(0.72±0.20),損傷組ATG7表達(dá)量為(1.52±0.23),處理組ATG7表達(dá)量為(1.63±0.25);對照組LC3Ⅰ表達(dá)量為(0.93±0.23),損傷組LC3Ⅰ表達(dá)量為(0.87±0.10),處理組LC3Ⅰ表達(dá)量為(0.39±0.05);對照組LC3Ⅱ表達(dá)量為(0.36±0.05),損傷組LC3Ⅱ表達(dá)量為(0.46±0.08),處理組LC3Ⅱ表達(dá)量為(1.08±0.12)。結(jié)果顯示:處理組中ATG7表達(dá)顯著增強(qiáng),同時(shí),LC3Ⅰ含量減少,而LC3Ⅱ含量增加。見圖2。
2.4 依達(dá)拉奉激活mTOR信號通路 本研究將RNA-seq結(jié)果借助KEGG數(shù)據(jù)庫進(jìn)行注釋和分析,結(jié)果表明:損傷組相對于對照組有4條信號通路發(fā)生了顯著性變化,其中mTOR信號通路和Caspase介導(dǎo)的信號通路被激活(圖3A),說明損傷組細(xì)胞的凋亡被啟動,氧化損傷增加了細(xì)胞凋亡;而處理組與對照組相比,有12條信號通路發(fā)生了顯著性增強(qiáng),其中mTOR信號通路和MAPK信號通路被激活,而與細(xì)胞凋亡密切相關(guān)的Caspase信號通路沒有顯著增強(qiáng)(圖3B),說明處理組的依達(dá)拉奉降低了細(xì)胞凋亡,而增強(qiáng)了細(xì)胞自噬。
3 討論
MAPK/JNK信號通路被激活后會影響應(yīng)激損傷狀態(tài)下細(xì)胞的存活。先前諸多實(shí)驗(yàn)證實(shí)細(xì)胞自噬以及細(xì)胞內(nèi)MAPK/JNK信號通路活化在缺血性腦卒中等多種神經(jīng)系統(tǒng)疾病的病理過程中發(fā)揮了重要作用[15]。其中mTOR-MAPK信號通路對下游JNK因子有正調(diào)控作用。文獻(xiàn)[16]顯示細(xì)胞內(nèi)氧自由基的增高是影響細(xì)胞自噬關(guān)鍵因素之一,而且尤為重要,且氧自由基能調(diào)節(jié)MAPK/JNK等多種信號轉(zhuǎn)導(dǎo)途徑。自由基增高是引起神經(jīng)細(xì)胞凋亡和神經(jīng)組織水腫的主要原因[17],本研究也觀察到了氧化損傷可引起細(xì)胞凋亡。
細(xì)胞自由基清除劑依達(dá)拉奉通過降低細(xì)胞內(nèi)自由基濃度實(shí)現(xiàn)抗腦水腫和保護(hù)神經(jīng)系統(tǒng)免受傷害的作用[18]。盡管目前依達(dá)拉奉被廣泛應(yīng)用于腦出血的治療中,但是其抑制腦出血后MAPK/JNK/Caspase-3表達(dá)機(jī)制尚不清楚,該機(jī)制與細(xì)胞自噬的發(fā)生及疾病的緩解密切相關(guān)。
本研究結(jié)果顯示:損傷組PC12細(xì)胞繁殖下降,而處理組細(xì)胞數(shù)量接近對照組,表明H2O2給PC12神經(jīng)元細(xì)胞造成損傷并抑制了細(xì)胞的生長,但是在添加依達(dá)拉奉后,細(xì)胞的繁殖情況明顯變好,說明依達(dá)拉奉能夠有效保護(hù)PC12細(xì)胞免受氧化損傷,具有拮抗氧化劑和細(xì)胞氧化應(yīng)激的能力。而后進(jìn)一步的流式細(xì)胞儀實(shí)驗(yàn)顯示,處理組PC12細(xì)胞沒有發(fā)生明顯的凋亡,而損傷組細(xì)胞凋亡率稍高,表明H2O2誘發(fā)了PC12細(xì)胞凋亡,但是添加依達(dá)拉奉后觀察到細(xì)胞的凋亡率很低,接近對照組,猜測可能是依達(dá)拉奉降低了氧自由基,同時(shí)降低了細(xì)胞凋亡。為了深入分析其凋亡降低的機(jī)制,采用Western blot分析PC12細(xì)胞是否發(fā)生了自噬,結(jié)果顯示:處理組中ATG7表達(dá)顯著增強(qiáng),同時(shí),LC3Ⅰ含量減少,而LC3Ⅱ含量增加。在添加依達(dá)拉奉后,細(xì)胞自噬標(biāo)記性基因的表達(dá)明顯上升。說明依達(dá)拉奉可能通過誘發(fā)細(xì)胞自噬啟動細(xì)胞存活的自我保護(hù)機(jī)制,避免受到氧損傷而死亡。
為了進(jìn)一步說明依達(dá)拉奉加強(qiáng)了細(xì)胞自噬,進(jìn)行了RNA-seq研究,轉(zhuǎn)錄組數(shù)據(jù)利用生物信息學(xué)進(jìn)行KEGG分析,KEGG是涵蓋基因組信息、化學(xué)信息和生化系統(tǒng)功能的綜合數(shù)據(jù)庫,擁有16個(gè)子數(shù)據(jù)庫[19]。結(jié)果顯示在損傷組中細(xì)胞凋亡和自噬等關(guān)聯(lián)信號通路都被激活,而添加依達(dá)拉奉后自噬關(guān)聯(lián)信號通路被顯著激活而凋亡途徑?jīng)]有顯著差異,說明依達(dá)拉奉激活了細(xì)胞自噬?;谏鲜鰧?shí)驗(yàn),筆者認(rèn)為依達(dá)拉奉對氧損傷神經(jīng)元具有顯著防護(hù)作用,其通過增強(qiáng)細(xì)胞自噬功能而對細(xì)胞進(jìn)行防護(hù)。
參考文獻(xiàn)
[1] ZHANG C,XIA B J,GE H,et al.Long-Term Mortality Related to Acute Kidney Injury Following Intracerebral Hemorrhage: A 10-Year (2010-2019) Retrospective Study[J].Journal of Stroke and Cerebrovascular Diseases,2021,30(5):105688.
[2] XU X,ZHANG J,YANG K,et al.Prognostic prediction of hypertensive intracerebral hemorrhage using CT radiomics and machine learning[J].Brain and Behavior,2021,11(5):e02085.
[3] Shoamanesh A,Katsanos A H.Combatting Secondary Injury From Intracerebral Hemorrhage With Supplemental Antioxidant Therapy[J].Stroke,2021,52(4).
[4] Salim S.Oxidative Stress and the Central Nervous System[J].
J Pharmacol Exp Ther,2017,360(1):201-205.
[5] Ozkul A,Akyol A,Yenisey C,et al.Oxidative stress in acute ischemic stroke[J].Journal of Clinical Neuroscience,2007,14(11):1062-1066.
[6] Magid-Bernstein J,Beaman C B,Poyraz F C,et al.Impacts of ABO Incompatible Platelet Transfusions on Platelet Recovery and Outcomes after Intracerebral Hemorrhage[J].Blood,2021,137(19):2699-2703.
[7] Sies H.Oxidative stress: oxidants and antioxidants[J].Experimental Physiology,1997,82(2):291-295.
[8] Vries H,Witte M,Hondius D,et al.Nrf2-induced antioxidant protection: a promising target to counteract ROS-mediated damage in neurodegenerative disease?[J].Free Radic Biol Med,2008,45(10):1375-1383.
[9] Wei R,Enaka M,Muragaki Y.Activation of KEAP1/NRF2/P62 signaling alleviates high phosphate-induced calcification of vascular smooth muscle cells by suppressing reactive oxygen species production[J].Sci Rep,2019,9(1):10366.
[10]祝丹丹,夏磊,陳泉,等.依達(dá)拉奉對腦出血血腫周圍水腫的影響[J].心腦血管病防治,2021,21(1):90-92.
[11]王力波,貝赟,秦東旭,等.依達(dá)拉奉通過Nrf2信號分子調(diào)節(jié)氧化應(yīng)激減輕腦缺血再灌注誘導(dǎo)的神經(jīng)損傷[J].中國生物化學(xué)與分子生物學(xué)報(bào),2020,36(3):328-336.
[12] LIU X,WU Y,ZHOU D,et al.Nlinoleyltyrosine protects PC12 cells against oxidative damage via autophagy: Possibleinvolvement of CB1 receptor regulation[J].International Journal of Molecular Medicine,2020,46(5):1827-1837.
[13]李福記,梁靖梅,段秀萍,等.苦參堿對TGF-β1誘導(dǎo)的人腹膜間皮細(xì)胞ETS2表達(dá)的影響[J].中國現(xiàn)代醫(yī)生,2020,58(6):30-33.
[14]于瑜,王鐘興.基于生物信息學(xué)途徑篩選缺血性腦卒中關(guān)鍵基因及藥物預(yù)測[J].中山大學(xué)學(xué)報(bào)(醫(yī)學(xué)科學(xué)版),2021,42(1):42-50.
[15] Schellino R,Boido M,Vercelli A.JNK Signaling Pathway Involvement in Spinal Cord Neuron Development and Death[J].Cells,2019,8(12):1576.
[16] LI N,LU X Y,SHI W Y,et al.Combined mTOR/MEK inhibition prevents proliferation and induces apoptosis in NF2-mutant tumors[J].Eur Rev Med Pharmacol Sci,2019,23(13):5874-5883.
[17] Paasz A,Segovia Y,Skowronek R,et al.Molecular neurochemistry of the lanthanides[J/OL].Synapse,2019,73(9):e22119.
[18] MIAO H,JIANG Y,GENG J,et al.Edaravone Administration Confers Neuroprotection after Experimental Intracerebral Hemorrhage in Rats via NLRP3 Suppression[J].Journal of Stroke and Cerebrovascular Diseases,2019,29(1):104468.
[19]郭俊愷,趙承磊,趙興旺,等.通過生物信息學(xué)分析鑒定干燥綜合征的關(guān)鍵基因[J].中國麻風(fēng)皮膚病雜志,2021,37(3):131-135,152.
(收稿日期:2021-04-07) (本文編輯:姬思雨)