龍瀛，歐陽(yáng)瑤，張婧

(遵義醫(yī)學(xué)院附屬醫(yī)院，貴州遵義563000)

慢性阻塞性肺疾病(以下稱(chēng)慢阻肺)是以持續(xù)呼吸系統(tǒng)癥狀及氣流受限為特征的慢性疾病。目前認(rèn)為，氣道和肺部炎癥、氧化/抗氧化失衡和蛋白酶/抗蛋白酶失衡是其主要發(fā)病機(jī)制。除此之外，自主神經(jīng)功能失調(diào)、營(yíng)養(yǎng)不良、吸煙、氣溫變化等可能亦參與慢阻肺的發(fā)生、發(fā)展。氣道和肺實(shí)質(zhì)的慢性炎癥是慢阻肺的特征性改變，吞噬細(xì)胞、T細(xì)胞、中性粒細(xì)胞等多種炎癥細(xì)胞均參與其發(fā)病過(guò)程。炎癥細(xì)胞被激活后，釋放多種炎性介質(zhì)，引起氣道和肺實(shí)質(zhì)的異常炎癥反應(yīng)，破壞肺結(jié)構(gòu)，導(dǎo)致外周氣道、肺實(shí)質(zhì)的炎癥和水腫，黏液過(guò)度分泌和纖維化，引起氣道狹窄，氣流阻力增加，最終導(dǎo)致病情惡化[3,4]。近年研究認(rèn)為，慢阻肺還是一種自身免疫性疾病[5，6]，T細(xì)胞介導(dǎo)的免疫應(yīng)答在慢阻肺的發(fā)病過(guò)程中起關(guān)鍵作用[7,8]。目前慢阻肺免疫發(fā)病機(jī)制的研究熱點(diǎn)主要涉及CD4+T細(xì)胞介導(dǎo)的免疫應(yīng)答，特別是輔助性T細(xì)胞17(Th17)、調(diào)節(jié)性T細(xì)胞(Treg)[9,10]。高遷移率族蛋白1(HMGB1)擁有諸多生物學(xué)功能，與炎癥反應(yīng)、細(xì)胞凋亡等關(guān)系密切，是一種重要的晚期炎癥介質(zhì)，在不同炎癥反應(yīng)中均有表達(dá)。本研究對(duì)Th17/Treg及高遷移率族蛋白1(HMGB1)在慢阻肺中作用的研究進(jìn)展作一綜述。

1 Th17/Treg在慢阻肺中的作用

Th17是CD4+T淋巴細(xì)胞的一個(gè)亞系，是一類(lèi)能夠誘導(dǎo)中性粒細(xì)胞聚合的前炎性細(xì)胞因子，并可催化其他細(xì)胞生成炎癥因子，促進(jìn)炎癥因子動(dòng)員、募集及活化，從而介導(dǎo)炎癥反應(yīng)，在自身免疫系統(tǒng)中有著十分關(guān)鍵的作用。Th17可生成IL-17A、IL-17F，在誘導(dǎo)趨化因子、促炎因子釋放之后，可直接導(dǎo)致組織細(xì)胞受損。Th17主要通過(guò)產(chǎn)生IL-17，開(kāi)始啟動(dòng)并逐步放大免疫反應(yīng)，在較多慢性炎癥性疾病發(fā)病過(guò)程中起到極為關(guān)鍵的作用，并可參與自身免疫性疾病的發(fā)病[11，12]。在慢阻肺中，有許多細(xì)胞參與其病理生理過(guò)程，其中最重要的是中性粒細(xì)胞、巨噬細(xì)胞和CD4+CD8+T細(xì)胞，中性粒細(xì)胞遷移到炎癥區(qū)域主要是通過(guò)CD4+Th17相關(guān)的細(xì)胞因子介導(dǎo)，已經(jīng)證實(shí)，IL-17A、IL-17F和IL-22可誘導(dǎo)氣道上皮細(xì)胞分泌CXCL8、CXCL1、CXCL5、G-CSF和GM-CSF[13]。Vargas-Rojas等[14]研究表明，慢阻肺患者外周血 Th17細(xì)胞較健康者增多，細(xì)胞數(shù)量與肺功能呈負(fù)相關(guān)關(guān)系，伴隨氣流受限程度加重而增加。與健康者相比，慢阻肺患者支氣管黏膜下層IL-17A、IL-17F表達(dá)明顯升高，提示 Th17細(xì)胞可直接參與慢阻肺的發(fā)生、發(fā)展和支氣管組織重組[14]。同樣，小鼠長(zhǎng)期暴露于香煙煙霧后肺組織內(nèi)IL-17表達(dá)明顯升高[15]，同時(shí)其肺上皮細(xì)胞所釋放的IL-17可引起與慢阻肺相似的肺部嚴(yán)重感染。Chu等[16]研究表明，慢阻肺患者Th17細(xì)胞的轉(zhuǎn)錄因子維甲酸相關(guān)孤核受體γt(RORγt)表達(dá)升高。上述研究顯示，Th17細(xì)胞和對(duì)應(yīng)細(xì)胞因子在慢阻肺的發(fā)生、發(fā)展中具有極為重要的作用。

相反，Treg是一種擁有抑制作用的T細(xì)胞亞群，能抑制潛在的、可被激活為效應(yīng)細(xì)胞的自身反應(yīng)性T細(xì)胞，促進(jìn)免疫系統(tǒng)獲得免疫耐受，在控制自身免疫反應(yīng)中發(fā)揮重要作用[17]。Treg對(duì)機(jī)體過(guò)度活躍的免疫反應(yīng)提供必要的保護(hù)，并在慢性炎癥中產(chǎn)生和誘導(dǎo)細(xì)胞因子。Treg生成減少或功能缺陷將導(dǎo)致自身免疫性疾病[18]。研究發(fā)現(xiàn)，肺氣腫及慢阻肺患者較健康志愿者Treg數(shù)量減少[19]；慢阻肺非吸煙患者Treg數(shù)量少于吸煙患者[20]。但在慢阻肺患者中Treg的免疫抑制作用仍存在爭(zhēng)議。有報(bào)道，長(zhǎng)時(shí)間暴露于煙霧環(huán)境中會(huì)導(dǎo)致氣道中Treg數(shù)量增多[21]；其在穩(wěn)定期慢阻肺患者體內(nèi)數(shù)量遠(yuǎn)高于健康者[22]；與不吸煙者比較，慢阻肺吸煙患者小氣道中Treg特異性轉(zhuǎn)錄因子數(shù)量減少，而大氣道中Treg數(shù)量增多[23]?？梢?jiàn)，與兩者在分化過(guò)程中相互抑制，功能上相互拮抗，兩者之間的平衡對(duì)于維持體內(nèi)免疫內(nèi)環(huán)境平衡起重要作用[24]，一旦失衡，即可導(dǎo)致多種自身免疫性疾病發(fā)生[25]。在慢阻肺小鼠模型體內(nèi)Th17及其相關(guān)的細(xì)胞因子(IL-17A、IL-6和IL -23)顯著增多，而Treg及其相關(guān)的細(xì)胞因子(IL-10)則顯著減少[25]。并且在慢阻肺小鼠模型中Th17的轉(zhuǎn)錄因子RORγt表達(dá)亦增高，Treg的轉(zhuǎn)錄因子Foxp3表達(dá)減少[26]。本課題組前期研究表明，慢阻肺小鼠模型外周血、BALF及肺組織中Th17的百分比高于健康小鼠，而Treg的百分比則低于健康小鼠。慢阻肺急性加重期和穩(wěn)定期患者RORγt表達(dá)增加，與病情嚴(yán)重程度表現(xiàn)出線(xiàn)性關(guān)系，并且與肺功能呈負(fù)相關(guān)關(guān)系[27]。以上研究提示，Th17/Treg失衡可參與慢阻肺的免疫發(fā)病機(jī)制。

2 HMGB1在慢阻肺中的作用

HMGB1是一類(lèi)擁有促炎功能的核內(nèi)非組蛋白，由A盒(A-box)、B盒(B-box)和C端尾部3個(gè)結(jié)構(gòu)域組成。HMGB1能夠經(jīng)由活化以后的免疫細(xì)胞分泌到細(xì)胞外，也可由壞死的細(xì)胞釋放，之后轉(zhuǎn)移到炎癥處，與有關(guān)受體，如Toll樣受體2(TLR2)、TLR4等結(jié)合促進(jìn)炎性細(xì)胞因子生成并介導(dǎo)下游炎癥反應(yīng)[28]。研究表明，HMGB1信號(hào)參與膿毒癥、腫瘤、關(guān)節(jié)炎等疾病的發(fā)生[29～31]；吸煙者和慢阻肺患者血漿中HMGB1水平升高。慢阻肺患者血漿HMGB1水平顯著高于不吸煙者及吸煙無(wú)慢阻肺者，且與肺功能顯著相關(guān)[32,33]。Kanazawa等[34]研究發(fā)現(xiàn)，慢阻肺吸煙患者氣道HMGB1表達(dá)顯著高于非吸煙者，且HMGB1表達(dá)與氣流堵塞密切聯(lián)系。Ferhani等[33]報(bào)道，慢阻肺患者支氣管活檢和肺組織切片HMGB1表達(dá)明顯高于健康吸煙者。研究發(fā)現(xiàn)，慢阻肺患者氣道上皮細(xì)胞和黏膜下層細(xì)胞HMGB1表達(dá)明顯升高[34]；慢阻肺患者痰液HMGB1水平升高且與慢阻肺的嚴(yán)重程度呈線(xiàn)性關(guān)系；血液中HMGB1水平亦升高[35]；HMGB1表達(dá)與慢阻肺炎癥和病理改變的嚴(yán)重程度存在一定正相關(guān)關(guān)系[36]。上述研究結(jié)果提示，HMGB1可能通過(guò)與多種炎癥介質(zhì)相互作用而放大炎癥反應(yīng)，從而參與慢阻肺的發(fā)病。

3 HMGB1與TH17/Treg的關(guān)系

有研究表明，HMGB1能夠通過(guò)與晚期糖基化終末產(chǎn)物受體(RAGE)結(jié)合而參與慢阻肺的炎癥反應(yīng)[37]，但其具體機(jī)制尚不完全明確。RAGE是細(xì)胞表面受體的免疫球蛋白超級(jí)家族一員，能識(shí)別病原體和宿主的內(nèi)源性配體，以啟動(dòng)對(duì)組織損傷、感染和炎癥的免疫反應(yīng)。盡管在肺生理學(xué)和病理生理學(xué)中RAGE的作用尚不清楚，但最近的全基因組關(guān)聯(lián)研究已經(jīng)將RAGE基因多態(tài)性與氣流阻塞聯(lián)系起來(lái)[38]。研究發(fā)現(xiàn)，RAGE在慢阻肺患者氣道上皮平滑肌高表達(dá)，且與HMGB1一同定位，而在正常機(jī)體中則沒(méi)有這種情況[39]。Th17和Treg均表達(dá)RAGE，故HMGB1可能與這兩種細(xì)胞上的RAGE相互作用來(lái)調(diào)節(jié)其平衡。HMGB1與一些免疫炎癥性疾病中T細(xì)胞介導(dǎo)的免疫失調(diào)有關(guān)。如在小鼠急性移植排斥反應(yīng)模型中發(fā)現(xiàn)，HMGB1可誘導(dǎo)同種反應(yīng)性T 細(xì)胞產(chǎn)生IL-17[40]。此外，在慢性乙型肝炎患者外周血中RORγt表達(dá)升高，F(xiàn)oxp3表達(dá)減少，而且RORγt/Foxp3失衡與HMGB1表達(dá)增加有關(guān)，通過(guò)抗HMGB1抗體抑制HMGB1表達(dá)可使RORγt表達(dá)降低而Foxp3表達(dá)增加，從而調(diào)節(jié)這種失衡；HMGB1 能通過(guò)TLR4-IL-6 軸來(lái)調(diào)節(jié)慢性乙型肝炎患者Th17/Treg 平衡[41]。有資料顯示，哮喘小鼠HMGB1濃度和細(xì)胞數(shù)量均較對(duì)照組明顯升高，重組高遷移率族蛋白1可誘導(dǎo)DCs分泌IL-23，從而啟動(dòng)哮喘小鼠Th17細(xì)胞應(yīng)答，并通過(guò)體內(nèi)外實(shí)驗(yàn)證實(shí)，抑制HMGB1表達(dá)可調(diào)控這種免疫失調(diào)[42]。上述研究提示，在這些疾病的發(fā)病機(jī)制中Th17/Treg失衡與HMGB1表達(dá)有關(guān)。

綜上所述，在慢阻肺的發(fā)病機(jī)制中HMGB1可導(dǎo)致Th17/Treg失衡，進(jìn)而導(dǎo)致慢阻肺的發(fā)生、發(fā)展?？笻MGB1抗體可抑制HMGB1表達(dá)，繼而使RORγt表達(dá)降低、Foxp3表達(dá)增加，從而調(diào)節(jié)Th17/Treg失衡。

參考文獻(xiàn)：

[1] Vogelmeier CF,Criner GJ,Martinez FJ,et al. Global strategy for diagnosis,management and prevention of chronic obstructive lung disease 2017 report: GOLD executive summary[J]. Respirology,2017,22(3):575-601.

[2] Miravitlles M. Cough and sputum production as risk factors for poor outcomes in patients with COPD[J]. Respir Med,2011,105(8):1118-1128.

[3] 孫沛，丁逸鵬 慢性阻塞性肺疾病危險(xiǎn)因素及發(fā)病機(jī)理研究進(jìn)展[J].海南醫(yī)學(xué),2015，26(9):1324-1327.

[4] Nikoletta R,Antonia K,Nikolaos G,et al. Inflammation and immune response in COPD: where do we stand[J]. Mediators Inflamm,2013,2013:413735.

[5] Jin Y,Wan Y,Chen G,et al. Treg/IL-17 ratio and Treg differentiation in patients with COPD[J]. PLoS One,2014,9(10):e111044.

[6] Lugade AA,Bogner PN,Thatcher TH,et al. Cigarette smoke exposure exacerbates lung inflammation and compromises immunity to bacterial infection[J]. J Immunol,2014,192(11):5226-35.

[7] Chiappori A,Folli C,Balbi F,et al. CD4+CD25 high CD127-regulatory T-cells in COPD: smoke and drugs effect[J]. World Allergy Organ J,2016,9(1):1-7.

[8] Duan MC,Zhang JQ,Liang Y,et al. Infiltration of IL-17-producing T Cells and treg cells in a mouse model of smoke-induced emphysema[J]. Inflammation,2016,39(4):1334-1344.

[9] Tan DB,Fernandez S,Price P,et al. Impaired function of regulatory T-cells in patients with chronicobstructive pulmonary disease (COPD)[J]. Immunobiology,2014,219(12):975-979.

[10] Li XN,Pan X,Qiu D. Imbalances of Th17 and Treg cells and their respective cytokines in COPD patients by disease stage[J]. Int J Clin Exp Med,2014,7(12):5324-5329.

[11] Kuchroo VK,Awasthi A. Emerging new roles of Th17 cells[J]. Eur J Immunol,2012,42(9):2211-2214.

[12] Lee HS,Park HW,Song WJ,et al. TNF-α enhance Th2 and Th17 immune responses regulating by IL23 during sensitization in asthma model[J]. Cytokine,2016(79):23-30.

[13] Ponce-Gallegos MA,Ramire-Venegas A,Falfan-Valencia R. Th17 profile in COPD exacerbations[J]. Int J Chron Obstruct Pulmon Dis,2017,22(12):1857-1865.

[14] Vargas-Rojas MI,Ramírez-Venegas A,Limón-Camacho L,et al. Increase of Th17 cells in peripheral blood of patients with chronic obstructive pulmonary disease[J]. Res Med,2011,105(11):1648-1654.

[15] Harrison OJ,Foley J,Bolognese BJ,et al. Airway infiltration of CD4+CCR6+Th17 type cells associated with chronic cigarette smoke induced airspace enlargement[J]. Immunol Lett,2008(121):13-21.

[16] Chu S,Zhong X,Zhang J,et al. The expression of Foxp3 and ROR gamma t in lung tissues from normal smokers and chronic obstructive pulmonary disease patients[J]. Int Immunopharmacol,2011,11(11):1780-1788.

[17] Dancer R,Sansom DM. Regulatory T cells and COPD[J]. Thorax,2013,68(12):1176-1178.

[18] Costantino C,Baecher-Allan CD. Human regulatory T cells and autoimmunity[J]. Eur J Immunol,2008,38(4):921-924.

[19] Lee SH,Goswami S,Grudo A,et al. Antielastin autoimmunity in tobacco smoking-induced emphysema[J]. Nat Med,2007,13(5):567-569.

[20] Roos-Engstrand E,Ekstrand-Hammarstr?m B,Pourazar J,et al. Influence of smoking cessation on airway T lymphocyte subsets in COPD[J]. COPD,2009,6(2):112-120.

[21] Lucy J C,Smyth,Cerys,Starkey,Jorgen,Vestbo,et al. CD4-regulatory cells in COPD patients[J]. Chest,2007,132(1):156-163.

[22] 陳鋼，謝燦茂，羅志揚(yáng)，等.慢性阻塞性肺疾病加重期和穩(wěn)定期Th17和Treg細(xì)胞的表達(dá)[J].中山大學(xué)學(xué)報(bào)(醫(yī)學(xué)科學(xué)版)，2013，34(6)：917-921.

[23] Handono K,Firdausi SN,Pratama MZ,et al. Vitamin A improve Th17 and Treg regulation in systemic lupus erythematosus[J]. Clin Rheumatol,2016,35(3):631-638.

[24] Lane N,Robins RA,Corne J,et al. Regulation in chronic obstructive pulmonary disease: the role of regulatory T-cells and Th17 cells[J]. Clin Sci (Lond),2010,119(2):75-86.

[25] Lim SM,Kang GD,Jeong JJ,et al. Neomangiferin modulates the Th17/Treg balance and ameliorates colitis in mice[J]. Phytomedicine,2016,23(2):131-140.

[26] Wang H,Peng W,Weng Y,et al. Imbalance of Th17/Treg cells in mice with chronic cigarette smoke exposure[J]. Int Immunopharmacol,2012,14(4):504-512.

[27] Wang Huaying,Ying Huajuan,Wang Shi,et al. Imbalance of peripheral blood Th17 and Treg responses in patients with chronic obstructive pulmonary disease[J]. Clin Res J,2014,9:330-341.

[28] Yang H,Antoine DJ,Andersson U,et al. The many faces of HMGB1:molecular structure-functionalactivity in inflammation,apoptosis,and chemotaxis[J]. J Leukoc Biol,2013,93(6):865-873.

[29] Yang Q,Liu X,Yao Z,et al. Penehyclidine hydrochloride inhib-its the release of high-mobility group box 1 in lipopolysaccharide-activated RAW264.7 cells and cecal ligation and puncture-induced septic mice[J]. J Surg Res，2014，186(1):310-317.

[30] Musumeci D,Roviello GN,Montesarchio D. An overview on HMGB1 inhibitors as potential therapeutic agents in HMGB1-related pathologies[J]. Pharmacol Ther,2014，14(3): 347-357.

[31] He ZW,Qin YH，Wang ZW，et al. HMGB1 acts in synergy with lipopolysaccharide in activating rheumatoid synovial fibroblasts via p38 MAPK and NF-κB signaling pathways[J]. Med Inflamm，2013，2013:596716.

[32] Ko HK,Hsu WH,Hsieh CC,et al. High expression of high-mobility group box 1 in the blood and lung s is associated with the development of chronic obstructive pulmonary disease in smokers[J]. Respirology,2014,19(2):253-261.

[33] Ferhani N,Letuve S,Kozhich A,et al. Expression of high-mobility group box 1 and of receptor for advanced glycation end products in chronic obstructive pulmonary disease[J]. Am J Respir Crit Care Med,2010,181(9):917-927.

[34] Kanazawa H,Tochino Y,Asai K，et al. Validity of HMGB1 measurement in epithelial lining fluid in patients with COPD[J]. Eur J Clin Invest，2012,42(4):419-426.

[35] Hou C，Zhao H,Liu L,et al. High mobility group protein B1(HMGB1) in asthma :comparison of patients with chronic obstructive pulmonary disease and healthy controls[J]. Mol Med,2011,17(7-8):807-815.

[36] 楊曉敏,楊華.慢性阻塞性肺疾病患者肺組織和血清高遷移率族蛋白B1的表達(dá)[J].實(shí)用醫(yī)學(xué)雜志,2013,29(18):3009-3011.

[37] Weitzenblum E,Chaouat A,Canuet M,et al. Pulmonary hypertension in chronic obstructive pulmo nary disease and interstitial lung diseases[J]. Semin Respir Crit Med，2009，30(4)：458-470.

[38] Sukkar MB,Ullah MA,Gan WJ,et al. RAGE： a new frontier in chronic airways disease[J]. Br J Pharmacol,2012,167(6):1161-1176.

[39] Ferhani N,Letuve S,Kozhich A,et al. Expression of high-mobility group box 1 and of receptor for adv anced glycation e nd products in chronic obstructive pulmonary disease[J]. Am J Respir Crit Care Med,2010,181(9):917-927.

[40] Duan L,Wang CY,Chen J,et al. High-mobility group box 1 promotes early acute allograft rejection by enhancing IL-6-dependent Th17 alloreactive response[J]. Lab Invest,2011,91(1):43-53.

[41] Li J,Wang FP,She WM,et al. Enhanced high-mobility group box 1 (HMGB1) modulates regulatory lls (Treg)/T helper 17 (Th17) balance via toll-like receptor (TLR)-4-interleukin (IL)-6 pathway in patients with chronic hepatitis B[J]. J Viral Hepat,2014,21(2):129-140.

[42] Zhang F,Huang G,Hu B,et al. Recombinant HMGB1 A box protein inhibits Th17 responses in mice with neutrophilic asthma by suppressing dendritic cell-mediated Th17 polarization[J]. Int Immunopharmacol,2015,24(1):110-118.