摘要目的:探討苦杏仁苷(AMG)對(duì)脂多糖(LPS)誘導(dǎo)的心肌細(xì)胞炎癥反應(yīng)的影響及對(duì)高遷移率族ATHook蛋白1(HMGA1)/核因子-κB(NF-κB)信號(hào)通路的調(diào)節(jié)機(jī)制。方法:將H9c2心肌細(xì)胞分為對(duì)照組、LPS組、AMG低劑量組、AMG高劑量組、AMG高劑量+重組HMGA1組(AMG高+HMGA1組)。采用四甲基偶氮唑藍(lán)(MTT)檢測(cè)心肌細(xì)胞的增殖活性;流式細(xì)胞術(shù)檢測(cè)心肌細(xì)胞凋亡率;酶聯(lián)免疫吸附法(ELISA)檢測(cè)細(xì)胞培養(yǎng)液炎性因子白細(xì)胞介素(IL)-6、IL-1β、腫瘤壞死因子(TNF)-α;蛋白免疫印跡法(Western Blot)檢測(cè)心肌細(xì)胞HMGA1/NF-κB通路相關(guān)蛋白的表達(dá)。結(jié)果:與對(duì)照組比較,LPS組心肌細(xì)胞存活率、NF-κB抑制蛋白α(IκBα)蛋白表達(dá)降低,心肌細(xì)胞凋亡率、炎性因子IL-6、IL-1β、TNF-α含量、HMGA1蛋白和NF-κB p65、IκBα磷酸化水平升高(P<0.05)。與LPS組比較,AMG各劑量組心肌細(xì)胞存活率、IκBα蛋白表達(dá)升高,心肌細(xì)胞凋亡率、炎性因子IL-6、IL-1β、TNF-α含量、HMGA1蛋白和NF-κB p65、IκBα磷酸化水平降低(P<0.05),且HMGA1過(guò)表達(dá)可逆轉(zhuǎn)AMG對(duì)心肌細(xì)胞的保護(hù)作用(P<0.05)。結(jié)論:AMG通過(guò)抑制HMGA1/NF-κB信號(hào)通路,減輕LPS誘導(dǎo)的心肌細(xì)胞炎癥反應(yīng)。
關(guān)鍵詞心肌細(xì)胞;苦杏仁苷;高遷移率族ATHook蛋白1/核因子-κB信號(hào)通路;炎癥反應(yīng);實(shí)驗(yàn)研究
doi:10.12102/j.issn.1672-1349.2024.18.007
Effect of Amygdalin on LPS-induced Myocardial Inflammation by Regulating HMGA1/NF-κB Signaling Pathway
YANG Gaining, SU Haiyan
No.215 Hospital of Shaanxi Nuclear Industry, Xianyang 712000, Shaanxi, China
Corresponding AuthorSU Haiyan, E-mail: 3335171801@qq.com
AbstractObjective:To investigate the effect of amygdalin(AMG)on lipopolysaccharide(LPS)-induced myocardial inflammation and its regulatory mechanism of high mobility ATHook protein 1(HMGA1)/nuclear factor-κB(NF-κB) signaling pathway.Methods:H9c2 cardiomyocytes were divided into control group,LPS group,AMG low-dose group,AMG high-dose group,AMG high-dose + recombinant HMGA1 group(AMG high +HMGA1 group).The proliferative activity of cardiomyocytes was detected by tetramethylazolium blue(MTT).Cardiomyocyte apoptosis rate was detected by flow cytometry.The inflammatory factors interleukin(IL)-6,IL-1β and tumor necrosis factor(TNF)-α were detected by enzyme-linked immunosorbent assay(ELISA).The expressions of HMGA1/NF-κB pathway related proteins in cardiomyocytes were detected by Western Blot.Results:Compared with the control group,the survival rate of cardiomyocytes and the expression of NF-κB inhibitory protein α(IκBα) decreased in the LPS group,while the apoptosis rate,inflammatory factor IL-6,IL-1β,TNF-α content,HMGA1 protein and phosphorylation levels of NF-κB p65 and IκBα increased(P<0.05).Compared with the LPS group,the survival rate of cardiomyocytes and the expression of IκBα protein increased in AMG dose groups,while the apoptosis rate,inflammatory factor IL-6,IL-1β,TNF-α content,HMGA1 protein and phosphorylation levels of NF-κB p65 and IκBα decreased(P<0.05).Overexpression of HMGA1 could reverse the protective effect of AMG on cardiomyocytes(P<0.05).Conclusion:AMG could attenuate LPS-induced myocardial inflammation by inhibiting the HMGA1/NF-κB signalling pathway.
Keywordscardiomyocytes; amygdalin; high mobility ATHook protein 1/nuclear factor-κB signaling pathway; inflammatory response; experimental study
心肌炎是由感染、免疫反應(yīng)和中毒引起的心肌炎癥,其持續(xù)性發(fā)生可能導(dǎo)致心肌細(xì)胞結(jié)構(gòu)和功能異常,臨床癥狀主要表現(xiàn)為心律失常、急性心力衰竭、心源性休克等心肌功能障礙,但由于心肌炎癥狀多樣,與其他心血管疾病高度相似,且缺乏特異的診斷方法,目前尚無(wú)有效的治療方法[1-2]。因此,研究心肌炎的發(fā)病機(jī)制對(duì)尋找新的治療方法具有重要意義。高遷移率族ATHook蛋白1(high-mobility group AT-hook 1,HMGA1)作為結(jié)構(gòu)性轉(zhuǎn)錄因子是高遷移率族蛋白家族成員之一,除與多種癌癥的發(fā)生密切相關(guān)外,與心肌梗死、心肌細(xì)胞肥大、冠狀動(dòng)脈微栓塞等多種心血管疾病有關(guān)[3-4]。核因子-κB(NF-κB)是細(xì)胞內(nèi)重要的核轉(zhuǎn)錄因子,可釋放多種促炎因子。有研究指出,HMGA1/NF-κB信號(hào)通路在炎癥的發(fā)展中發(fā)揮著重要作用,抑制該信號(hào)通路可減輕冠狀動(dòng)脈微栓塞術(shù)誘導(dǎo)的心肌損傷[5]。脂多糖(LPS)是一種存在于革蘭氏陰性菌細(xì)胞壁中的細(xì)菌內(nèi)毒素,通過(guò)激活NF-κB信號(hào)通路促進(jìn)心肌細(xì)胞炎性因子產(chǎn)生,加劇心肌損傷[6-7]。苦杏仁苷(amygdalin,AMG)也稱為維生素B17,是一種含氰基的糖苷化合物,具有消炎、止咳化痰及抗腫瘤的作用,通過(guò)抑制Toll樣受體4(TLR4)/NF-κB信號(hào)通路,改善LPS誘導(dǎo)的支氣管上皮細(xì)胞炎癥損傷[8]。關(guān)于LPS誘導(dǎo)的心肌細(xì)胞損傷的作用機(jī)制尚未明確。本研究旨在探討AMG是否通過(guò)調(diào)節(jié)HMGA1/NF-κB信號(hào)通路對(duì)LPS誘導(dǎo)的心肌細(xì)胞炎癥產(chǎn)生影響。
1材料與方法
1.1實(shí)驗(yàn)材料和儀器
大鼠心肌細(xì)胞H9c2(貨號(hào):BW-5335,北京博沃爾斯生物科技有限公司);四甲基偶氮唑藍(lán)(MTT)細(xì)胞增殖活性檢測(cè)試劑盒(貨號(hào):R20228,上海源葉生物科技有限公司);膜聯(lián)蛋白V-異硫氰酸熒光素/碘化丙錠(Annexin V-FITC/PI)細(xì)胞凋亡檢測(cè)試劑盒(貨號(hào):E-CK-A211,武漢伊萊瑞特生物科技股份有限公司);白細(xì)胞介素(IL)-6酶聯(lián)免疫吸附法(ELISA)檢測(cè)試劑盒(貨號(hào):E0079r,武漢伊艾博科技股份有限公司);IL-1β、腫瘤壞死因子(TNF)-α ELISA檢測(cè)試劑盒(貨號(hào):EK-R36877、EK-R38696,廣州博輝生物科技有限公司);HMGA1、磷酸化NF-κB p65(p-NF-κB p65)、NF-κB抑制蛋白α(IκBα)、磷酸化IκBα(p-IκBα)一抗(貨號(hào):ab129153、ab76302、ab32518、ab133462,英國(guó)Abcam公司);羊抗兔免疫球蛋白G(貨號(hào):SPA9-1,北京索萊寶科技有限公司);CytoFLEX流式細(xì)胞儀(貝克曼庫(kù)爾特國(guó)際貿(mào)易有限公司);Tecan Spark多功能酶標(biāo)儀(上海帝肯實(shí)驗(yàn)器材有限公司);ChemiDoc MP System全能型成像系統(tǒng)(伯樂生命醫(yī)學(xué)產(chǎn)品有限公司)。
1.2細(xì)胞培養(yǎng)
將心肌細(xì)胞H9c2用含有10%的胎牛血清和1%青霉素-鏈霉素抗生素的DEME培養(yǎng)基,置于37 ℃,5% CO2的培養(yǎng)箱中培養(yǎng),待細(xì)胞的匯合率達(dá)到80%后進(jìn)行傳代,之后選擇生長(zhǎng)狀態(tài)較好的細(xì)胞繼續(xù)后續(xù)實(shí)驗(yàn)。
1.3細(xì)胞模型建立和分組
將培養(yǎng)的H9c2心肌細(xì)胞分為對(duì)照組、LPS組、AMG低劑量組、AMG高劑量組、AMG高劑量+重組HMGA1組(AMG高+HMGA1組)。除對(duì)照組外,其余組別心肌細(xì)胞均參照文獻(xiàn)[9]加入含1 μg/mL的LPS培養(yǎng)基培養(yǎng)24 h誘導(dǎo)細(xì)胞損傷;AMG低劑量組、AMG高劑量組心肌細(xì)胞分別用含80、320 μmol/L的AMG培養(yǎng)基培養(yǎng)[10];AMG高+HMGA1組用含320 μmol/L的AMG的培養(yǎng)基培養(yǎng),轉(zhuǎn)染HMGA1重組蛋白的細(xì)胞。
1.4MTT檢測(cè)心肌細(xì)胞的增殖活性
將心肌細(xì)胞按照1.3中的分組接種至96孔板中培養(yǎng)(4×103個(gè)/孔),每組設(shè)置6個(gè)復(fù)孔,每孔加入100 μL細(xì)胞培養(yǎng)物;24 h后,每孔中加入20 μL MTT溶液,37 ℃孵育4 h,之后棄上清,加入150 μL二甲基亞砜(DMSO)溶解晶體,使用酶標(biāo)儀檢測(cè)570 nm下各孔的吸光度,每組實(shí)驗(yàn)重復(fù)3次。
1.5流式細(xì)胞術(shù)檢測(cè)心肌細(xì)胞凋亡
收集心肌細(xì)胞按照1.3中的分組接種于6孔板中(2×105個(gè)/孔),培養(yǎng)24 h后棄上清收集細(xì)胞,之后用1×結(jié)合緩沖液重懸細(xì)胞,再依次加入5 μL的Annexin V-FITC和5 μL的PI,室溫孵育15 min,采用流式細(xì)胞儀檢測(cè)細(xì)胞凋亡情況并計(jì)算凋亡率。
1.6ELISA檢測(cè)心肌細(xì)胞培養(yǎng)液炎性因子IL-6、IL-1β、TNF-α水平
收集按照1.3分組培養(yǎng)24 h的細(xì)胞培養(yǎng)液,以3 000×重力加速度(g),離心5 min,收集上清。采用ELISA試劑盒檢測(cè)炎性因子IL-6、IL-1β、TNF-α含量。
1.7蛋白免疫印跡法(Western Blot)檢測(cè)心肌細(xì)胞HMGA1/NF-κB通路相關(guān)蛋白的表達(dá)
收集分組培養(yǎng)24 h后的H9c2心肌細(xì)胞,加入RIPA裂解液并提取總蛋白,之后進(jìn)行十二烷基硫酸鈉-聚丙烯酰胺凝膠電泳(SDS-PAGE),分離蛋白樣品并轉(zhuǎn)移至聚偏二氟乙烯(PVDF)膜。將PVDF膜置入含5%的脫脂牛奶中孵育2 h,之后與一抗稀釋液(HMGA1、p-NF-κB p65、IκBα比例為1∶2 000,p-IκBα比例為1∶10 000)4 ℃孵育過(guò)夜,再與羊抗兔IgG二抗稀釋液(1∶1 000)室溫下孵育2 h,最后采用電化學(xué)發(fā)光(ECL)顯色試劑顯色。以甘油醛-3-磷酸脫氫酶(GAPDH)為內(nèi)參,在凝膠成像儀中成像,應(yīng)用Image J軟件分析蛋白灰度值。
1.8統(tǒng)計(jì)學(xué)處理
采用GraphPad Prism 8.0軟件分析數(shù)據(jù)。符合正態(tài)分布的定量資料以均數(shù)±標(biāo)準(zhǔn)差(x±s)表示,多組間比較采用單因素方差分析,兩兩多重比較采用SNK-q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各組心肌細(xì)胞存活率比較
與對(duì)照組比較,LPS組心肌細(xì)胞存活率降低(P<0.05);與LPS組比較,AMG各劑量組、AMG高+HMGA1組心肌細(xì)胞存活率升高(P<0.05);與AMG高劑量組比較,AMG高+HMGA1組心肌細(xì)胞存活率降低(P<0.05)。詳見表1。
2.2AMG對(duì)心肌細(xì)胞凋亡率的影響
與對(duì)照組比較,LPS組心肌細(xì)胞凋亡率升高(P<0.05);與LPS組比較,AMG各劑量組、AMG高+HMGA1組心肌細(xì)胞凋亡率降低(P<0.05);與AMG高劑量組比較,AMG高+HMGA1組心肌細(xì)胞凋亡率升高(P<0.05)。詳見圖1、表2。
2.3AMG對(duì)心肌細(xì)胞炎性因子IL-6、IL-1β、TNF-α含量的影響
與對(duì)照組比較,LPS組心肌細(xì)胞培養(yǎng)液中IL-6、IL-1β、TNF-α含量升高(P<0.05);與LPS組比較,AMG各劑量組、AMG高+HMGA1組心肌細(xì)胞培養(yǎng)液中IL-6、IL-1β、TNF-α含量降低(P<0.05);與AMG高劑量組比較,AMG高+HMGA1組心肌細(xì)胞培養(yǎng)液中IL-6、IL-1β、TNF-α含量升高(P<0.05)。詳見表3。
2.4AMG對(duì)H9c2心肌細(xì)胞HMGA1/NF-κB通路相關(guān)蛋白的影響
與對(duì)照組比較,LPS組心肌細(xì)胞HMGA1、p-NF-κB p65、p-IκBα蛋白表達(dá)升高,IκBα蛋白表達(dá)降低(P<0.05);與LPS組比較,AMG各劑量組、AMG高+HMGA1組心肌細(xì)胞HMGA1、p-NF-κB p65、p-IκBα蛋白表達(dá)降低,IκBα蛋白表達(dá)升高(P<0.05);與AMG高劑量組比較,AMG高+HMGA1組心肌細(xì)胞HMGA1、p-NF-κB p65、p-IκBα蛋白表達(dá)升高,IκBα蛋白表達(dá)降低(P<0.05)。詳見表4、圖2。
3討論
心肌炎是由各種因素引起的危及生命的心血管疾病,如感染或接觸有毒物質(zhì)和免疫系統(tǒng)激活等,均可導(dǎo)致心臟功能障礙,也是膿毒癥等多種疾病的并發(fā)癥。目前關(guān)于心肌炎的發(fā)病機(jī)制尚未明確,而加大關(guān)于心肌炎的研究對(duì)新藥物的開發(fā)具有重要幫助[11-12]。天然物質(zhì)因廣泛的可用性和相對(duì)較低的成本廣泛用于各種疾病的治療。AMG是廣泛存在于薔薇科植物中的一種芳香族生氰化合物,已被推廣作為天然抗癌劑,具有抗菌、抗炎及免疫活性調(diào)節(jié)等多種藥理作用[13-14]。有研究表明,AMG通過(guò)抑制炎性因子分泌,減輕LPS誘導(dǎo)的急性肝損傷[15]。關(guān)于LPS誘導(dǎo)的心肌細(xì)胞損傷的作用機(jī)制尚未明確。LPS是炎癥反應(yīng)的關(guān)鍵介質(zhì)之一,可引發(fā)全身炎癥、多器官衰竭及心功能受損,常用于模擬心肌細(xì)胞炎癥[16]。本研究利用LPS誘導(dǎo)心肌細(xì)胞,結(jié)果顯示,LPS組心肌細(xì)胞存活率降低,凋亡率升高,促進(jìn)炎性因子IL-6、IL-1β、TNF-α釋放;AMG各劑量組心肌細(xì)胞存活率升高,凋亡率降低,減少了IL-6、IL-1β、TNF-α釋放。提示AMG可抑制心肌細(xì)胞凋亡及炎性因子的釋放,從而促進(jìn)細(xì)胞增殖,減輕LPS誘導(dǎo)的心肌細(xì)胞損傷。
HMGA1蛋白是一種核結(jié)構(gòu)因子,具有高遷移率,主要調(diào)節(jié)染色質(zhì)結(jié)構(gòu)、轉(zhuǎn)錄調(diào)節(jié)蛋白與下游DNA的相互作用,促進(jìn)多種類型癌癥的發(fā)生[17]。相關(guān)研究顯示,HMGA1通過(guò)增強(qiáng)NF-κB的轉(zhuǎn)錄活性誘導(dǎo)參與炎癥反應(yīng)的基因表達(dá)[5,18]。NF-κB是一個(gè)可誘導(dǎo)信號(hào)調(diào)節(jié)因子家族,調(diào)節(jié)一系列基因,刺激誘導(dǎo)炎癥反應(yīng)進(jìn)程,其中p65亞基是構(gòu)成NF-κB的有效轉(zhuǎn)錄激活因子[19]。IκBα是NF-κB抑制劑家族的一員,其被泛素依賴性蛋白酶體降解后,促進(jìn)p65磷酸化并轉(zhuǎn)移至細(xì)胞核,進(jìn)而促進(jìn)炎性因子的分泌[20]。本研究結(jié)果顯示,LPS組心肌細(xì)胞HMGA1蛋白和NF-κB p65、IκBα磷酸化水平升高,IκBα蛋白表達(dá)降低,AMG各劑量組HMGA1蛋白和NF-κB p65、IκBα磷酸化水平降低,IκBα蛋白表達(dá)升高。進(jìn)一步應(yīng)用重組HMGA1蛋白轉(zhuǎn)染培養(yǎng)細(xì)胞發(fā)現(xiàn),HMGA1過(guò)表達(dá)可逆轉(zhuǎn)AMG對(duì)心肌細(xì)胞的保護(hù)作用。提示AMG可抑制HMGA1/NF-κB通路被激活,阻止NF-κB p65進(jìn)入細(xì)胞核轉(zhuǎn)錄激活,從而減輕LPS誘導(dǎo)的心肌細(xì)胞炎性損傷。
綜上所述,AMG通過(guò)抑制HMGA1/NF-κB信號(hào)通路,進(jìn)而減輕LPS誘導(dǎo)的心肌細(xì)胞炎癥。本研究為治療心肌炎等心血管疾病提供了新方向。但關(guān)于HMGA1在炎性損傷疾病方面的研究較少,作用機(jī)制尚未明確,今后需對(duì)本研究結(jié)果進(jìn)行體內(nèi)實(shí)驗(yàn)驗(yàn)證。
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(收稿日期:2023-04-03)
(本文編輯薛妮)