宋鐵峰,王 楠,王會(huì)琴,袁 穎,黃麗文,莊春雨,張同存
(工業(yè)發(fā)酵微生物教育部重點(diǎn)實(shí)驗(yàn)室,天津市工業(yè)微生物重點(diǎn)實(shí)驗(yàn)室,天津科技大學(xué)生物工程學(xué)院,天津 300457)
PKCα 抑制劑Calphostin C抑制TNF-α 誘導(dǎo)的骨髓間充質(zhì)干細(xì)胞遷移
宋鐵峰,王 楠,王會(huì)琴,袁 穎,黃麗文,莊春雨,張同存
(工業(yè)發(fā)酵微生物教育部重點(diǎn)實(shí)驗(yàn)室,天津市工業(yè)微生物重點(diǎn)實(shí)驗(yàn)室,天津科技大學(xué)生物工程學(xué)院,天津 300457)
腫瘤壞死因子α(tumor necrosis factor-α,TNF-α )可以誘導(dǎo)間充質(zhì)干細(xì)胞(mesenchymal stem cells,MSCs)的遷移,但其促進(jìn)遷移機(jī)制尚不清楚.研究使用Calphostin C抑制劑來抑制PKCα 的活性,從而研究TNF-α 誘導(dǎo)MSCs遷移的作用是否通過激活PKCα 來完成.利用50,ng/mL的TNF-α 處理MSCs,劃痕實(shí)驗(yàn)和Transwell實(shí)驗(yàn)表明TNF-α 可以誘導(dǎo)MSCs的遷移.加入PKCα 的抑制劑Calphostin C后,可以抑制TNF-α 對(duì)MSCs遷移或侵襲的誘導(dǎo),并降低遷移標(biāo)志基因MYL9(Myosin light chain 9,MYL9)、CYR61(Cysteine rich 61,CYR61)的表達(dá).以上結(jié)果表明,PKCα抑制劑Calphostin C可以抑制TNF-α 誘導(dǎo)的MSCs遷移.
MSCs;遷移;TNF-α;PKCα
間充質(zhì)干細(xì)胞(mesenchymal stem cells,MSCs)是一種具有多向分化能力的干細(xì)胞[1-3].間充質(zhì)干細(xì)胞不僅具有多向分化潛能,還能靶向遷移到損傷部位、慢性炎癥部位及腫瘤部位,對(duì)于這些部位起到一定程度的修復(fù)作用[4].對(duì)于間充質(zhì)干細(xì)胞遷移機(jī)制的研究,有助于理解間充質(zhì)干細(xì)胞“歸巢”的分子機(jī)制,為自體修復(fù)和細(xì)胞治療提供理論依據(jù).間充質(zhì)干細(xì)胞的體內(nèi)歸巢和體外遷移也像細(xì)胞的其他生理活動(dòng)一樣由不同因素誘導(dǎo)引發(fā)涉及不同的信號(hào)通路[5-7].雖然多種誘導(dǎo)因子和信號(hào)通路被發(fā)現(xiàn)參與間充質(zhì)干細(xì)胞的遷移過程,但是其具體的遷移機(jī)制依然不明確.
腫瘤壞死因子(tumor necrosis factor,TNF),能引起腫瘤出現(xiàn)壞死,而對(duì)正常組織細(xì)胞無毒性,故稱之為腫瘤壞死因子.腫瘤壞死因子有 3種亞型:TNF-α、TNF-β和 TNF-γ.TNF-α主要由單核細(xì)胞分泌,但在其他細(xì)胞中也有分泌,包括間充質(zhì)干細(xì)胞[8-9].作為炎癥因子,TNF-α可以促進(jìn)間充質(zhì)干細(xì)胞的遷移,TNF-α 在MSCs遷移和黏附中均占有重要的作用.
蛋白激酶C(protein kinase C,PKC)是1977年在鼠腦的胞質(zhì)成分中發(fā)現(xiàn)的一種蛋白激酶,屬于多功能絲氨酸和蘇氨酸激酶,是 G蛋白偶聯(lián)受體信號(hào)轉(zhuǎn)導(dǎo)系統(tǒng)中的效應(yīng)物.絲氨酸/蘇氨酸激酶,PKC家族有3個(gè)亞家族:經(jīng)典型 PKCS(α、β和 γ同種型)、新型PKCS(δ、θ、η、ε同種型)以及非典型PKCS(ζ和ι亞型)[10-11].當(dāng)被激活時(shí),PKC磷酸化并轉(zhuǎn)運(yùn)到細(xì)胞膜,可調(diào)節(jié)信號(hào)轉(zhuǎn)導(dǎo)途徑[12],參與多種細(xì)胞遷移和侵襲過程.有文獻(xiàn)[13]報(bào)道,在肝癌細(xì)胞中 PKCα的表達(dá)誘導(dǎo)細(xì)胞的遷移和侵襲.有研究[14]顯示,TNF-α 通過PKC信號(hào)通路誘導(dǎo)肺腺癌細(xì)胞遷移.
研究發(fā)現(xiàn),TNF-α可促進(jìn)MSCs遷移,但TNF-α影響MSCs遷移的機(jī)制目前仍不清楚.因此,在本研究中,首先用TNF-α誘導(dǎo)MSCs遷移,再采用PKCα的特異性抑制劑Calphostin C,進(jìn)一步研究PKCα 在TNF-α 促進(jìn)MSCs遷移這一過程中的作用.
1.1材料
1.1.1實(shí)驗(yàn)動(dòng)物
健康SD(sprague dawley,SD)大鼠,由中國(guó)人民解放軍軍事醫(yī)學(xué)科學(xué)院實(shí)驗(yàn)動(dòng)物中心提供,實(shí)驗(yàn)動(dòng)物許可證號(hào)為SCXK-(軍)2012-0004,實(shí)驗(yàn)過程中對(duì)動(dòng)物的處置符合動(dòng)物倫理學(xué)標(biāo)準(zhǔn).
1.1.2主要試劑
DMEM/LG培養(yǎng)基,Gibco公司;胎牛血清,浙江天杭生物科技有限公司;重組大鼠TNF-α,Peprotech公司;Calphostin C、MYL9抗體、CYR61抗體、β-actin抗體,Santa Cruz公司;DAPI、dNTP,北京索萊寶科技有限公司;IRDye?800,CW山羊抗鼠抗體、IRDye?680 山羊抗兔抗體,LI-COR公司;M-MLV逆轉(zhuǎn)錄酶、Trizol裂解液,上海英俊生物技術(shù)有限公司;隨機(jī)引物 B0043,上海生工生物工程有限公司;Bestar?SybGreen qPCR Mastermix,DBI?Bioscience公司.
1.2方法
1.2.1骨髓間充質(zhì)干細(xì)胞的提取及體外擴(kuò)增培養(yǎng)
SD大鼠間充質(zhì)干細(xì)胞的提取采用全骨髓貼壁法.選健康80~90,g的 SD大鼠,雄性,頸椎脫臼法處死.剪刀剪去皮毛,無菌條件下取股骨和脛骨,剔除骨表面肌肉.吸取含15%,胎牛血清的DMEM/LG放入已滅菌玻璃離心管中.剪開股骨、脛骨關(guān)節(jié)兩端,用 5,mL一次性注射器吸取培養(yǎng)基沖洗骨髓腔.將帶有骨髓懸浮物的培養(yǎng)液用移液器吹散后,轉(zhuǎn)移到培養(yǎng)皿中,置于37,℃、5%, CO2培養(yǎng)箱中進(jìn)行原代細(xì)胞培養(yǎng).本研究所用的是第 3~7代的骨髓間充質(zhì)干細(xì)胞.
1.2.2細(xì)胞加藥處理
將MSCs以1×105,mL-1的密度接種于6孔板,分為4組:對(duì)照組,2%,血清DMEM/LG處理細(xì)胞;TNF-α 組,加 TNF-α(終質(zhì)量濃度 50,ng/mL)于 2%,血清的 DMEM/LG中,處理細(xì)胞 24,h;Calphostin C組,用含Calphostin C(終濃度0.1,μmol/L)的2%,血清的DMEM/LG處理細(xì)胞24,h;Calphostin C+TNF-α組,先用含Calphostin C(終濃度0.1,μmol/L)的2%,血清的DMEM/LG處理細(xì)胞1,h,再加入終質(zhì)量濃度為50,ng/mL的 TNF-α處理細(xì)胞 24,h.加藥處理 24,h后,收集上述細(xì)胞進(jìn)行后續(xù)實(shí)驗(yàn).
1.2.3細(xì)胞劃痕實(shí)驗(yàn)
將MSCs以1×105,mL-1的密度接種于6孔板,12~16,h后用 10,μL槍頭在細(xì)胞間按“十”字型劃出痕跡,同時(shí)加藥處理,24,h后在倒置顯微鏡下進(jìn)行觀察拍照,觀察細(xì)胞的彌合修復(fù)能力.
1.2.4Transwell實(shí)驗(yàn)
在 24孔板中加入 500,μL 10%,血清 DMEM/ LG(含所加的藥 TNF-α),然后在小孔內(nèi)放入小室,使小室下膜與培養(yǎng)基完全契合.在小室的上室中加入 5×104個(gè)細(xì)胞,放入培養(yǎng)箱培養(yǎng).16,h后將Transwell的小室取出,用棉簽輕輕擦去上室的細(xì)胞,PBS洗2次,每次5,min.4%,多聚甲醛室溫固定下室細(xì)胞20,min,PBS洗2次,每次5,min.無水甲醇浸泡下室膜20,min,PBS洗2次,每次5,min.用DAPI染細(xì)胞核,室溫放置 15,min,PBS洗 2次,每次5,min.共聚焦顯微鏡下照相.
1.2.5RNA的提取
用 0.5,mL Trizol裂解液在冰上裂解細(xì)胞15,min,重復(fù)吹懸使細(xì)胞充分裂解,加入0.1,mL的氯仿,劇烈振蕩 15,s,靜置 5,min,4,℃、12,000,r/min離心 10,min.取上層水相到另一 EP管中,加入等體積的異丙醇,混勻,-20,℃放置 30,min.12,000,r/min離心 10,min,棄掉上清液,加入 75%,乙醇 1,mL,洗滌RNA,離心棄掉上清液,室溫晾干 RNA.加入 20,μL DEPC水溶解RNA,放于-80,℃保存.
1.2.6RNA逆轉(zhuǎn)錄及實(shí)時(shí)熒光定量 PCR(Real-time PCR)
將提取的RNA用M-MLV逆轉(zhuǎn)錄方法進(jìn)行逆轉(zhuǎn)錄.RNA 2,μg、隨機(jī)引物(B0043)5,μL,70,℃水浴5,min;迅速冰??;10,mol/L dNTPs 5,μL、5×buffer 5,μL、RNAse inhibitor 0.625,μL、M-MLVRT 1,μL混勻,37,℃反應(yīng)1,h;70,℃保持10,min終止反應(yīng).
用Bestar?SybGreen qPCR Mastermix進(jìn)行Realtime PCR.擴(kuò)增程序:95,℃ 2,min;95,℃ 10,s,60,℃30,s,72,℃ 30,s,40個(gè)循環(huán).融解曲線:95,℃ 1,min,55,℃ 1,min,95,℃ 10,s.目的基因引物:GAPDH上游5′-ATTCAACGGCACAGTCAAGG-3′,GAPDH下游5′-GCAGAAGGGGCGGAGATGA-3′;CYR61上游5′-GAAGAAATACCGGCCCAAAT-3′,CYR61下游5′-CAGACTGTAGAGGCGAAACGAC-3′;MYL9上游5′-ATGAGGAGGTGGACGAGATGT-3′,MYL9下游5′-CGTGCTTGAGGATGCGAG-3′.
1.2.7免疫印跡實(shí)驗(yàn)(Western blot)
收集各組細(xì)胞,PBS洗1次,SDS細(xì)胞裂解液冰上裂解細(xì)胞,100,℃變性10,min,12%, SDS-PAGE電泳,電轉(zhuǎn)法將蛋白轉(zhuǎn)至 NC膜.5%,的脫脂奶粉室溫封閉1,h后,分別用β-actin抗體(1∶500)、CYR61抗體(1∶500)、MYL9抗體(1∶500)4,℃孵育過夜,PBS洗3次,每次10,min;IRDye?800,CW 山羊抗鼠抗體(1∶5,000)、IRDye?680 山羊抗兔抗體(1∶5,000)室溫孵育 2,h后,PBS洗 3次,每次 10,min,Odyssey成像系統(tǒng)進(jìn)行掃膜成像.
1.2.8統(tǒng)計(jì)學(xué)分析
所有實(shí)驗(yàn)數(shù)據(jù)均用SPSS 13.0統(tǒng)計(jì)軟件計(jì)算,實(shí)驗(yàn)數(shù)據(jù)均以“平均值±標(biāo)準(zhǔn)差”表示.用t檢驗(yàn)顯著性,*表示統(tǒng)計(jì)學(xué)上有顯著性差異(P<0.05).
2.1劃痕檢測(cè)加入 Calphostin C后對(duì) TNF-α 誘導(dǎo)MSCs遷移作用的影響
利用劃痕實(shí)驗(yàn)檢測(cè)細(xì)胞的遷移能力,結(jié)果如圖 1所示.加入TNF-α 的MSCs細(xì)胞的愈合程度大于沒有處理的MSCs細(xì)胞的愈合程度,證明 TNF-α 可以促進(jìn)MSCs細(xì)胞的遷移.而加入Calphostin C+TNF-α 組的 MSCs細(xì)胞愈合程度小于加入 TNF-α 組的MSCs細(xì)胞愈合程度,證明 PKCα 的活性被抑制后,TNF-α 促進(jìn)MSCs細(xì)胞的遷移作用也被抑制.
圖1 Calphostin C抑制 TNF-α 誘導(dǎo)的 MSCs細(xì)胞遷移能力Fig.1 Calphostin C inhibits MSC migration induced by TNF-α
2.2Transwell檢測(cè)加入Calphostin C后對(duì)TNF-α促侵襲作用的影響
利用 Transwell實(shí)驗(yàn)檢測(cè)了細(xì)胞的侵襲能力,結(jié)果如圖2所示.
圖2 Calphostin C抑制TNF-α 誘導(dǎo)的MSCs細(xì)胞侵襲能力Fig.2 Calphostin C inhibits MSC invasion induced by TNF-α
加入TNF-α的MSCs細(xì)胞的侵襲能力大于沒有處理的 MSCs細(xì)胞的侵襲能力,證明 TNF-α可以促進(jìn)MSCs細(xì)胞的侵襲.而加入Calphostin C+TNF-α組的 MSCs細(xì)胞侵襲能力小于加入 TNF-α 組的MSCs細(xì)胞侵襲能力,證明 PKCα的活性被抑制后,TNF-α促進(jìn)MSCs細(xì)胞的侵襲作用也被抑制.
2.3檢測(cè)遷移marker的表達(dá)變化
細(xì)胞外基質(zhì)蛋白 CYR61、細(xì)胞骨架蛋白 MYL9與細(xì)胞遷移有直接的關(guān)系[15-16].利用 Real-time PCR的方法檢測(cè)遷移maker MYL9、CYR61,mRNA水平的變化,結(jié)果如圖3所示.TNF-α可以促進(jìn)MYL9、CYR61,mRNA 表達(dá)的升高,而加入 Calphostin C抑制 PKCα 的活性后,TNF-α 的這種上調(diào)遷移 marker表達(dá)的能力被抑制.
圖3 Calphostin C抑制 TNF-α 誘導(dǎo)的 MSCs細(xì)胞遷移maker mRNA表達(dá)水平Fig.3 Calphostin C inhibits the mRNA levels of migration markers induced by TNF-α in MSCs cells
利用Western blot檢測(cè)這兩種基因蛋白水平的變化,如圖4所示.結(jié)果與mRNA水平的變化一致,進(jìn)一步證明了TNF-α 促進(jìn)MSCs細(xì)胞的遷移能力是通過激活PKCα.
圖4 Calphostin C抑制 TNF-α誘導(dǎo)的 MSCs細(xì)胞遷移maker蛋白表達(dá)水平Fig.4 Calphostin C inhibits the protein expression of migration markers induced by TNF-α in MSCs cells
腫瘤壞死因子 TNF-α 分泌前體是跨膜蛋白,然后經(jīng)過 TNF-α 轉(zhuǎn)化酶的剪切修飾轉(zhuǎn)變?yōu)榭扇苄誀顟B(tài).每一種可溶性的亞型均有生理活性,TNF-α 的主要生理作用都是通過TNFR1,將信號(hào)傳達(dá)到細(xì)胞內(nèi),啟動(dòng)一系列的生理反應(yīng).作為炎癥因子,TNF-α 促進(jìn)間充質(zhì)干細(xì)胞的遷移已有相關(guān)研究.有研究[5]顯示,TNF-α 可以增強(qiáng)間充質(zhì)干細(xì)胞的遷移能力,增加ERK的磷酸化和p38蛋白的磷酸化;加入 p38的抑制劑 SB203580后,細(xì)胞間黏附分子 1(intercellular cell adhesion molecule-1,ICAM-1)表達(dá)升高,抑制了TNF-α 引起的間充質(zhì)干細(xì)胞的遷移.在 Ponte等[17]的研究中,發(fā)現(xiàn) TNF-α 可以大大增強(qiáng)趨化因子RANTES(regulated upon activation normal T cell expressed and secreted facyor,RANTES)和SDF-1(stromal-cell derived factor-1,SDF-1)誘導(dǎo) MSCs遷移的能力.PKCα 是信號(hào)傳導(dǎo)PKC的大家族成員之一,在肝癌細(xì)胞中,PKCα 激活A(yù)KT/MAPK信號(hào)通路,誘導(dǎo)細(xì)胞的增殖、遷移和侵襲[13].研究[14]顯示,在人的肺腺癌細(xì)胞中,TNF-α 誘導(dǎo)的 CLDN1(claudin-1,CLDN1)表達(dá)及細(xì)胞遷移通過 PKC信號(hào)通路.同時(shí)有文獻(xiàn)報(bào)道,MSCs的遷移與PKC信號(hào)通路相關(guān),Lin等[18]發(fā)現(xiàn)白細(xì)胞介素1β(interleukin 1β,IL-1β)通過 PKC信號(hào)通路激活肌球蛋白輕鏈激酶(myosin light chain kinase,MLCK),從而誘導(dǎo)MSCs遷移.Tang等[19]發(fā)現(xiàn)乙酰膽堿通過PKC信號(hào)通路誘導(dǎo)MSCs遷移.
本文發(fā)現(xiàn)TNF-α 可以促進(jìn)MSCs細(xì)胞遷移和侵襲,并且通過加入PKCα 特異性抑制劑Calphostin C證實(shí) TNF-α 誘導(dǎo) MSCs細(xì)胞遷移通過 PKCα 通路.接下來可以通過RNA干擾技術(shù)敲低PKCα ,進(jìn)一步驗(yàn)證結(jié)論作出補(bǔ)充.雖然多種誘導(dǎo)因子和信號(hào)通路被發(fā)現(xiàn)參與間充質(zhì)干細(xì)胞的遷移過程,但是其具體的遷移機(jī)制依然不明確.在 TNF-α 誘導(dǎo)的MSCs遷移過程中是否還存在其他分子參與其中,激活PKCα 從而促進(jìn)TNF-α 誘導(dǎo)MSCs遷移是不是唯一的途徑,這些問題還有待于進(jìn)一步研究.
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責(zé)任編輯:郎婧
Inhibiting the Migration of Mesenchymal Stem Cells Induced by TNF-α with PKCα Inhibitor Calphostin C
SONG Tiefeng,WANG Nan,WANG Huiqin,YUAN Ying,HUANG Liwen,ZHUANG Chunyu,ZHANG Tongcun
(Key Laboratory of Industrial Fermentation Microbiology,Ministry of Education,Tianjin Key Laboratory of Industrial Microbiology,College of Biotechnology,Tianjin University of Science & Technology,Tianjin 300457,China)
Inflammatory cytokine TNF-α can induce the migration of MSCs,but the mechanism of migration remains unclear.This study used PKCα inhibitor Calphostin C to inhibit PKCα activity,in order to know whether the migration of MSCs induced by TNF-α was accomplished by activating PKCα.MSCs were treated with 50,ng/mL of TNF-α.Wound heal assay and Transwell assay confirmed that TNF-α could induce the migration of MSCs.PKCα inhibitor Calphostin C inhibited TNF-α-induced MSC migration or invasion and reduced the expression of migration marker genes MYL9,and CYR61.In conclusion,PKCα inhibitor Calphostin C can inhibit the migration of MSCs induced by TNF-α.
MSCs;migration ability;TNF-α;PKCα
Q28
A
1672-6510(2016)04-0015-05
10.13364/j.issn.1672-6510.20150148
2015-10-08;
2015-12-08
國(guó)家自然科學(xué)基金資助項(xiàng)目(31171303)
宋鐵峰(1990—),女,黑龍江人,碩士研究生;通信作者:張同存,教授,tony@tust.edu.cn.