王東巖,楊海永,董旭,何雷,麻聰聰

·綜 述·

針刺調(diào)控a7nAchR 激活膽堿能抗炎通路的研究現(xiàn)狀

王東巖1,2,楊海永1,董旭1,2,何雷1,麻聰聰1

(1.黑龍江中醫(yī)藥大學(xué),哈爾濱 150040;2.黑龍江中醫(yī)藥大學(xué)附屬第二醫(yī)院,哈爾濱 150001)

膽堿能抗炎通路是一條神經(jīng)免疫通路,主要依靠乙酰膽堿與巨噬細(xì)胞及其他細(xì)胞表面上的a7nAchR相結(jié)合抑制促炎因子的合成與釋放,從而防止組織損傷。a7nAchR是膽堿能遞質(zhì)的主要受體,在膽堿能抗炎通路中起關(guān)鍵作用。針刺治療有明確的抗炎作用,其作用機(jī)制可能與調(diào)控a7nAchR激活膽堿能抗炎通路有關(guān)。近年來(lái)雖然國(guó)內(nèi)外學(xué)者對(duì)針刺抗炎機(jī)制進(jìn)行了大量研究,然而針刺抗炎的作用機(jī)制目前仍不明確。該文從膽堿能抗炎通路概述、a7nAchR結(jié)構(gòu)及功能、a7nAchR的分布、a7nAchR在膽堿能抗炎通路的作用、針刺調(diào)控a7nAchR激活膽堿能抗炎通路的機(jī)制等方面對(duì)針刺調(diào)控a7nAchR激活膽堿能抗炎通路進(jìn)行分析總結(jié),為今后探究針刺抗炎作用機(jī)制提供借鑒思路和科學(xué)依據(jù)。

針刺療法;乙酰膽堿;a7煙堿型乙酰膽堿受體;信號(hào)通路;神經(jīng)免疫調(diào)節(jié)

膽堿能抗炎通路(cholinergic anti-inflamma- tory pathway, CAP)是一條以迷走神經(jīng)、乙酰膽堿和特異性乙酰膽堿受體為基礎(chǔ),通過(guò)神經(jīng)反射作用抑制炎癥反應(yīng)的神經(jīng)-免疫調(diào)節(jié)通路。其作用機(jī)制是乙酰膽堿與巨噬細(xì)胞及其他細(xì)胞表面上的a7煙堿型乙酰膽堿受體(a7 nicotinic acetylcholine receptor,a7nAchR)結(jié)合,抑制炎性因子的合成與釋放從而防止組織損傷。

針刺療法在臨床已經(jīng)得到十分廣泛的應(yīng)用,越來(lái)越多的研究者重視針刺抗炎作用,大量的實(shí)驗(yàn)證明針刺能夠抑制炎性因子干擾素、白介素、TNF-a等的釋放,從而抑制炎癥反應(yīng)[1-2]。但針刺抗炎的作用機(jī)制目前仍不明確。相關(guān)研究表明針刺抗炎機(jī)制可能與激活膽堿能抗炎通路有關(guān),a7nAchR作為CAP的核心在針刺調(diào)控膽堿能通路中發(fā)揮重要作用[3]。因此探究針刺是否通過(guò)調(diào)控a7nAchR激活膽堿能通路是可能揭示針刺抗炎作用機(jī)制的關(guān)鍵問(wèn)題之一,為臨床治療各種炎性疾病提供新的治療思路。

1 膽堿能抗炎通路概述

CAP是根據(jù)膽堿能神經(jīng)調(diào)節(jié)或抑制全身炎癥反應(yīng)基礎(chǔ)提出的。Borovikova LV等[4]通過(guò)研究動(dòng)物模型及培養(yǎng)人體外周血巨噬細(xì)胞發(fā)現(xiàn)刺激外周迷走神經(jīng)傳出支或利用擬膽堿藥物可以抑制內(nèi)毒素血癥引發(fā)的炎癥反應(yīng),明顯降低細(xì)胞炎性因子如腫瘤壞死因子(tumor necrosis factor, TNF)、白介素1(interleukin-1, IL-1)與白介素6(interleukin-6, IL-6)等的釋放。根據(jù)以上研究結(jié)果Borovikova LV等[4]2000年在Nature發(fā)表文章首先提出“膽堿能抗炎通路”的概念。CAP發(fā)揮抗炎作用的基本原理是炎癥反應(yīng)過(guò)程中促炎因子作用于迷走神經(jīng)的傳入支,促進(jìn)迷走神經(jīng)釋放乙酰膽堿(acetylcholine, Ach),被釋放出的Ach與中樞神經(jīng)系統(tǒng)(central nervous system, CNS)的M受體相結(jié)合,再通過(guò)迷走神經(jīng)傳出支末端釋放的乙酰膽堿與機(jī)體內(nèi)免疫細(xì)胞上的a7nAchR相結(jié)合,從而抑制促炎因子的產(chǎn)生。膽堿能抗炎通路的受體主要為a7nAchR,它在膽堿能抗炎過(guò)程中起關(guān)鍵作用。Ach與a7nAchR結(jié)合后能夠使巨噬細(xì)胞失活,抑制巨噬細(xì)胞合成與釋放TNF-a、IL-1和IL-6等促炎細(xì)胞因子,從而起到抗炎作用[5]。

2 a7nAchR的結(jié)構(gòu)及功能

煙堿型乙酰膽堿受體(nicotinic acetylcholine receptors, nAchRs)是一種配體門(mén)控離子通道蛋白,主導(dǎo)突觸間快速信號(hào)的傳遞[6]。nAchRs大體可分為中樞型和外周型兩類(lèi)。nAchRs由不同亞單位組成,到目前為止已確認(rèn)了16種nAchRs亞單位,不同亞單位的nAchRs的藥理學(xué)和生理學(xué)特征不同。a7nAchRs是較為特殊的一種亞型,它由5個(gè)相同的亞基構(gòu)成,5個(gè)a7亞基構(gòu)成的同源聚合體的配體門(mén)控離子通道蛋白。a7亞基編碼基因包含10個(gè)外顯子,基因編碼、翻譯、修飾后5個(gè)亞基在Ric-3蛋白的作用下形成具有一定功能的同源聚合體a7nAchR。用親和標(biāo)記方法研究發(fā)現(xiàn)a7受體激動(dòng)劑的結(jié)合位點(diǎn)位于外顯子4、6、7決定的蛋白結(jié)構(gòu)中[7]。每個(gè)亞基含有502個(gè)氨基酸,各亞基聯(lián)合形成一個(gè)中心通道,亞基相連的區(qū)域有配基結(jié)合位點(diǎn),其與配基結(jié)合可改變受體狀態(tài)[8]。

a7nAchR是煙堿型乙酰膽堿能受體的成員,作用于突觸后膜、突觸前膜、突觸周?chē)炔课话l(fā)揮其特定功能。當(dāng)刺激突觸前膜a7nAchR時(shí),可以促進(jìn)囊泡與突觸前膜的融合、胞吐與Ca2﹢內(nèi)流從而興奮電壓依賴(lài)性鈣通道引發(fā)突觸前膜去極化,最終促進(jìn)或激發(fā)相應(yīng)遞質(zhì)的釋放[如谷氨酸、多巴胺、去甲腎上腺素、乙酰膽堿、g-氨基丁酸(GABA)等][9]。當(dāng)興奮突觸后膜的a7nAchR不僅可以使突觸后膜去極化直接興奮神經(jīng)元,同時(shí)還可以調(diào)節(jié)GABA的釋放[10]。因此a7nAchR能夠調(diào)節(jié)神經(jīng)元興奮性使其維持正常的生理狀態(tài)。

3 a7nAchR的分布

a7nAchR分布較廣泛,在中樞海馬、前額皮層、基底核、顳葉皮層等區(qū)域及外周淋巴細(xì)胞、巨噬細(xì)胞等均廣泛分布,其中在海馬組織中含量最高[11]。

3.1 a7nAchR在外周的分布

a7nAchR于淋巴細(xì)胞、巨噬細(xì)胞、樹(shù)突狀細(xì)胞、角質(zhì)細(xì)胞及肺上皮細(xì)胞表面表達(dá)[12]。在免疫細(xì)胞中尤其是巨噬細(xì)胞表面的a7nAchR參與膽堿能抗炎通路并且發(fā)揮核心作用。膽堿能抗炎通路通過(guò)網(wǎng)狀內(nèi)皮系統(tǒng)(reticuloendothelial system, RES)支配的器官(包括肺、脾臟、肝臟、腎臟以及胃腸道)分泌Ach來(lái)抑制炎癥反應(yīng)。Ach與各類(lèi)免疫細(xì)胞表面上的a7nAchR相結(jié)合,結(jié)合物可以抑制或上調(diào)胞內(nèi)下游信號(hào)通路從而抑制促炎因子的合成與釋放最后起到減輕組織損害的目的。當(dāng)體外細(xì)胞培養(yǎng)液中加入Ach可以顯著降低LPS刺激體外巨噬細(xì)胞釋放各類(lèi)促炎細(xì)胞因子水平,當(dāng)Ach作用于敲除a7nAchRs基因的大鼠發(fā)現(xiàn),Ach的這個(gè)抗炎作用消失[13]。研究證實(shí)a7nAchRs是機(jī)體調(diào)控外周炎癥反應(yīng)的核心物質(zhì)[14]。

3.2 a7nAchR在中樞的分布

在中樞神經(jīng)系統(tǒng)中神經(jīng)細(xì)胞和非神經(jīng)細(xì)胞表面均有a7nAchR廣泛表達(dá),如星狀膠質(zhì)細(xì)胞、小膠質(zhì)細(xì)胞、少突膠質(zhì)細(xì)胞和內(nèi)皮細(xì)胞[15]。其中神經(jīng)細(xì)胞a7nAchRs的表達(dá)主要集中在海馬區(qū)神經(jīng)元區(qū)域,主要參與注意力、記憶力及認(rèn)知等功能。阿爾茲海默病和帕金森病的病理改變基礎(chǔ)可能是神經(jīng)細(xì)胞上a7nAchR功能失調(diào),因此a7nAchR結(jié)構(gòu)和表達(dá)水平的改變可能誘發(fā)多種神經(jīng)系統(tǒng)疾病。到目前為止a7nAchR功能改變對(duì)認(rèn)知功能的影響以及a7nAchRs調(diào)控在海馬神經(jīng)回路中信號(hào)傳遞的具體機(jī)制尚不清楚。研究推測(cè)其機(jī)理可能與a7nAchRs刺激引發(fā)胞內(nèi)鈣離子濃度升高,然后激活鈣依賴(lài)信號(hào)通路,從而增加谷氨酸的釋放量及提高谷氨酸能突觸的可塑性有關(guān)[16]。

4 a7nAchR抗炎作用

膽堿能抗炎通路是一條生理性神經(jīng)-免疫抗炎通路,以迷走神經(jīng)、乙酰膽堿和特異性乙酰膽堿受體為基礎(chǔ),能夠通過(guò)神經(jīng)反射來(lái)抑制炎癥反應(yīng)的神經(jīng)-免疫調(diào)節(jié)通路。該通路能夠調(diào)節(jié)免疫功能從而起到控制炎癥的作用。其作用機(jī)理主要通過(guò)Ach與巨噬細(xì)胞上的a7nAchR相互作用,抑制促炎因子的合成與釋放從而起到抗炎作用。相比于傳統(tǒng)的體液抗炎通路,膽堿能抗炎通路具有直接、迅速、高效等優(yōu)點(diǎn),而且能夠同時(shí)抑制多種炎癥因子。由于膽堿能抗炎通路的以上特性,a7nAchR是膽堿能抗炎系統(tǒng)的核心,目前正逐漸成為調(diào)控炎性反應(yīng)的新靶點(diǎn)。

4.1 a7nAchR在免疫細(xì)胞水平的抗炎作用

Borovikova LV等[4]研究發(fā)現(xiàn)Ach可以通過(guò)介導(dǎo)nAchR抑制LPS產(chǎn)生TNFa、IL-1、IL-6等炎性因子。Takahashi HK等[17]研究發(fā)現(xiàn)膽堿可以抑制脂多糖(LPS)誘導(dǎo)單核細(xì)胞釋放IL-18、IL-12等炎性因子,而a7nAchR拮抗劑能夠改變膽堿的此種抑制功效,因此可以推斷煙堿的抗炎作用機(jī)制與激活a7nAchR有必然的關(guān)系。Orr-Urtreger A等[18]研究發(fā)現(xiàn)膽堿能激動(dòng)劑可以抑制a7nAchR基因敲除小鼠巨噬細(xì)胞的抗炎作用,而a7nAchR基因敲除小鼠內(nèi)毒素血癥患病率卻增加,該研究相當(dāng)于迷走神經(jīng)切斷術(shù),該實(shí)驗(yàn)研究表明激活迷走神經(jīng)產(chǎn)生的生理性抗炎作用機(jī)制與a7nAchR密切相關(guān)。Wang H等[19]通過(guò)采用基因敲除技術(shù)定向敲除小鼠a7nAchR基因后研究發(fā)現(xiàn)小鼠膠原誘導(dǎo)的關(guān)節(jié)炎加重。體外研究發(fā)現(xiàn)nAchR激動(dòng)劑能夠抑制野生型小鼠巨噬細(xì)胞TNF-a的表達(dá),但對(duì)敲除a7nAchR基因小鼠的巨噬細(xì)胞TNF-a的表達(dá)無(wú)影響[20]。Xiang H等[21]通過(guò)對(duì)敗血癥患者的初步研究結(jié)果發(fā)現(xiàn)外周血單核細(xì)胞a7nAchR的mRNA表達(dá)水平高低是敗血癥患者膽堿能抗炎通路是否激活的臨床相關(guān)標(biāo)志,a7nAchR mRNA表達(dá)水平越高則患者的炎癥控制和預(yù)后越好[22]。

4.2 a7nAchR細(xì)胞內(nèi)抗炎作用

激活a7nAchR能夠顯著抑制促炎因子TNFa、IL-12、HMGB1等的表達(dá),并且能夠促進(jìn)轉(zhuǎn)化生長(zhǎng)因子b等抗炎因子的表達(dá)從而發(fā)揮抗炎作用[23]。研究表明當(dāng)激活a7nAchR后導(dǎo)致Ca2﹢內(nèi)流,從而調(diào)控NF-kB與Jak2/STAT3信號(hào)轉(zhuǎn)導(dǎo)通路[24]。炎癥條件下,當(dāng)a7nAchR被激活,迅速抑制蛋白激酶的活性,抑制IkB分子磷酸化,發(fā)揮抗炎作用。a7nAchR在中樞和外周細(xì)胞抗炎通路中均扮演十分重要的角色。a7nAchR受到刺激興奮后激活Jak2,導(dǎo)致STAT3出現(xiàn)磷酸化,進(jìn)而產(chǎn)生STAT3與其DNA反應(yīng)原件結(jié)合和激活。研究發(fā)現(xiàn)JAK2和STAT3在膽堿能抗炎過(guò)程中也發(fā)揮重要作用,并可被a7nAchR選擇性拮抗劑MLA抑制[25]。LPS刺激的中性粒細(xì)胞趨化因子巨噬細(xì)胞炎性蛋白也可被煙堿在炎性介質(zhì)的mRNA水平抑制。膽堿能抗炎通路的抗炎作用出現(xiàn)在上游轉(zhuǎn)錄水平,正如煙堿可抑制LPS刺激的IkB磷酸化,從而阻止NF-kB的激活,而NF-kB卻是促炎介質(zhì)基因轉(zhuǎn)錄的關(guān)鍵環(huán)節(jié)[26]。

5 針刺對(duì)a7nAchR的影響

Liu PR等[27]通過(guò)觀(guān)察電針對(duì)老年術(shù)后認(rèn)知功能障礙大鼠認(rèn)知功能的影響及其對(duì)海馬a7nAchR和促炎因子表達(dá)的調(diào)控作用。研究發(fā)現(xiàn)與模型組相比,電針組術(shù)后1 d、3 d、7 d的逃避潛伏期明顯縮短,平臺(tái)時(shí)間縮短(＜0.05)。術(shù)后第1天、第3天和第7天,海馬中a7nAchR陽(yáng)性神經(jīng)元減少,TNF-a和IL-1b陽(yáng)性神經(jīng)元增加。與模型組相比,電針組a7nAchR陽(yáng)性神經(jīng)元增加,同時(shí)TNF-a和IL-1b陽(yáng)性神經(jīng)元減少(＜0.05)。結(jié)果表明電針調(diào)節(jié)可以提高老年術(shù)后認(rèn)知功能障礙大鼠的學(xué)習(xí)記憶能力,其機(jī)制可能與上調(diào)a7nAchR,下調(diào)海馬TNF-a和IL-1b有關(guān)。Wang Y等[28]探究電針調(diào)控a7nAchR緩解選擇性神經(jīng)損傷(spared nerve injury, SNI)大鼠脊髓神經(jīng)病理性疼痛,研究發(fā)現(xiàn)2 Hz電針刺激可明顯提高a7nAchR的表達(dá),減少選擇性神經(jīng)損傷誘導(dǎo)的神經(jīng)病理性疼痛大鼠脊髓內(nèi)IL-1b的產(chǎn)生。當(dāng)鞘內(nèi)注射a7nAchR的選擇性拮抗劑a-銀環(huán)蛇毒素時(shí),不但能夠抑制EA在SNI大鼠中的鎮(zhèn)痛作用,同時(shí)抑制了a7nAchR的表達(dá)。研究表明2 Hz EA通過(guò)上調(diào)a7nAchR和下調(diào)SNI大鼠脊髓中IL-1b和CD11b來(lái)降低SNI誘導(dǎo)的機(jī)械超敏反應(yīng)。Liu J等[29]研究電針通過(guò)激活局灶性腦缺血/再灌注損傷大鼠a7nAchR介導(dǎo)的抗炎活性,減輕學(xué)習(xí)和記憶障礙,發(fā)現(xiàn)EA激活了海馬中a7nAchR的表達(dá)。此外,EA下調(diào)海馬中小膠質(zhì)細(xì)胞/巨噬細(xì)胞標(biāo)記物Iba1和星形膠質(zhì)細(xì)胞標(biāo)記物膠質(zhì)纖維酸性蛋白的表達(dá)。EA治療能夠抑制炎性細(xì)胞因子TNF-a和IL-1b的產(chǎn)生。用a7nAchR拮抗劑甲基烏頭堿治療減弱了EA治療后學(xué)習(xí)和記憶的改善以及EA對(duì)神經(jīng)膠質(zhì)細(xì)胞活化和炎性細(xì)胞因子產(chǎn)生的抑制作用。研究結(jié)果表明EA能夠通過(guò)激活a7nAchR來(lái)改善腦缺血性損傷后的學(xué)習(xí)和記憶功能,從而顯著降低神經(jīng)炎癥反應(yīng)。胡志蘋(píng)等[30]研究a7nAchR介導(dǎo)電針(100 Hz)調(diào)控自然殺傷細(xì)胞的細(xì)胞活性,研究結(jié)果顯示電針加拮抗劑組比電針組脾臟NK細(xì)胞活性明顯增強(qiáng),差異具有統(tǒng)計(jì)學(xué)意義(＜0.05),證明a7nAchR介導(dǎo)了電針(100 Hz)調(diào)節(jié)免疫功能的作用。

6 針刺調(diào)控a7nAchR激活膽堿能抗炎通路抗炎機(jī)制

當(dāng)機(jī)體發(fā)生炎癥刺激時(shí),刺激信號(hào)通過(guò)傳入迷走神經(jīng)傳遞至大腦孤束核,經(jīng)過(guò)中樞相關(guān)膽堿受體傳遞,通過(guò)興奮迷走神經(jīng)運(yùn)動(dòng)背核將神經(jīng)興奮通過(guò)迷走神經(jīng)傳出支傳遞,神經(jīng)末梢被刺激后從外周釋放Ach,與免疫細(xì)胞上的a7nAchR結(jié)合,通過(guò)NF-kB、JAK2/STAT3、PI3K/AKT等信號(hào)通路抑制TNF-a、IL-1、IL-6等多種炎性因子的產(chǎn)生與釋放,發(fā)揮抗炎作用[31-32]。

6.1 激活JAK2/STAT3通路

JAK2/STAT3通路介導(dǎo)細(xì)胞增殖、細(xì)胞分化、細(xì)胞凋亡及生物體免疫調(diào)節(jié)等多個(gè)生理過(guò)程,在生物體免疫調(diào)節(jié)過(guò)程中發(fā)揮重要作用。當(dāng)產(chǎn)生炎癥反應(yīng)時(shí),針刺通過(guò)刺激迷走神經(jīng),使神經(jīng)傳出纖維釋放Ach與a7nAchR抑制巨噬細(xì)胞活化發(fā)揮抗炎作用[33]。研究發(fā)現(xiàn)JAK2和STAT3在膽堿能抗炎過(guò)程中也發(fā)揮重要作用,并可被a7nAchR選擇性拮抗劑MLA抑制[34]。項(xiàng)水英[35]研究電針對(duì)COPD大鼠模型作用,研究結(jié)果顯示電針治療能夠抑制大鼠肺組織中NF-kB、JAK2及STAT3基因的表達(dá),抑制炎癥反應(yīng),說(shuō)明電針治療能夠抑制NF-kB與JAK2/STAT3信號(hào)轉(zhuǎn)導(dǎo)通路激活狀態(tài),當(dāng)大鼠體內(nèi)注射a7nAchR阻斷劑后,則電針的抗炎效應(yīng)明顯被抑制,證明電針的抗炎作用可能與調(diào)控a7nAchR激活CAP相關(guān)。其作用機(jī)制可能是針刺刺激興奮a7nAchR,激活JAK2,導(dǎo)致STAT3出現(xiàn)磷酸化,進(jìn)而產(chǎn)生STAT3與其DNA反應(yīng)原件結(jié)合和激活。促發(fā)膠質(zhì)細(xì)胞分泌炎性因子阻斷軸突-膠質(zhì)細(xì)胞的連接,從而影響神經(jīng)元正常功能。針刺可以調(diào)控a7nAchR的表達(dá),a7nAchR特異性激動(dòng)劑可以降低相關(guān)炎性因子的表達(dá),激活a7nAchR介導(dǎo)的膽堿能通路抑制炎性反應(yīng),a7nAchR特異性激動(dòng)劑又能夠抑制JAK2-STAT3,推測(cè)針刺可能調(diào)控a7nAchR激活JAK2-STAT3抑制炎癥反應(yīng)。

6.2 激活NF-kB通路

核因子kB(nuclear factorkB,NF-kB)是在炎性反應(yīng)中無(wú)法代替的轉(zhuǎn)錄因子,NF-kB在炎性反應(yīng)中能夠與多種炎性反應(yīng)調(diào)控基因的啟動(dòng)子相結(jié)合,從而調(diào)控炎癥反應(yīng)。針刺可能通過(guò)激活a7nAchR,抑制蛋白IkB被促炎因子磷酸化后所激活,NF-kB被炎性因子刺激活化后結(jié)合在目標(biāo)基因啟動(dòng)子上的kB結(jié)合位點(diǎn)上形成具有生物功能的復(fù)合體,從而調(diào)控炎癥反應(yīng)相關(guān)基因的轉(zhuǎn)錄,促進(jìn)大量促炎因子的表達(dá)[36-37]?？琢⒓t等[38]采用電針治療腦缺血大鼠大椎及雙側(cè)內(nèi)關(guān)穴,研究結(jié)果表明針刺可以降低腦缺血再灌注后TNF-a的含量,并且能夠下調(diào)NF-kB的表達(dá)抑制不良信號(hào)轉(zhuǎn)導(dǎo)對(duì)神經(jīng)細(xì)胞引起的損害。當(dāng)激活巨噬細(xì)胞表面上的a7nAchR,抑制NF-kB p65的磷酸化,從而抑制促炎細(xì)胞因子的合成與釋放[39]。研究發(fā)現(xiàn)當(dāng)各種針刺刺激激活a7nAchR后,其下游轉(zhuǎn)錄因子NF-kB的活性發(fā)生變化,從而影響細(xì)胞因子IL-1b與IL-8等的表達(dá)[40]。膽堿能抗炎通路的抗炎作用出現(xiàn)在上游轉(zhuǎn)錄水平,從而阻止NF-kB的激活,而NF-kB卻是促炎介質(zhì)基因轉(zhuǎn)錄的關(guān)鍵環(huán)節(jié)[41]。a7nAchR可能通過(guò)調(diào)控NF-kB信號(hào)轉(zhuǎn)導(dǎo)通路抑制炎癥反應(yīng)[42]。研究發(fā)現(xiàn)電針預(yù)處理能夠激活a7nAchR,降低HMGB1的釋放[43]。因此可以推測(cè)電針可能調(diào)控a7nAchR激活NF-kB通路,從而抑制炎癥反應(yīng)。

6.3 激活PI3K/AKT通路

PI3K/AKT是生物體內(nèi)非常重要的一條細(xì)胞內(nèi)信號(hào)傳導(dǎo)通路,PI3K是一種脂質(zhì)激酶,當(dāng)針刺刺激導(dǎo)致a7nAchR釋放激活膽堿能通路,使胞內(nèi)RTKs發(fā)生磷酸化從而激活PI3K蛋白,進(jìn)而調(diào)控下游介質(zhì)的表達(dá)[44-45]。針刺調(diào)控a7nAchR激活膽堿能通路使PI3K蛋白活化,激活產(chǎn)物可以與AKT表面上的PH結(jié)構(gòu)域相結(jié)合,從而激活A(yù)KT調(diào)控細(xì)胞生長(zhǎng)、凋亡,進(jìn)而抑制促炎細(xì)胞因子釋放[46]。研究發(fā)現(xiàn)針刺調(diào)控a7nAchR的表達(dá),a7nAchR能夠激活PI3K/AKT信號(hào)傳導(dǎo)通路,通過(guò)調(diào)控抗氧化酶等因子的表達(dá),從而調(diào)控炎性因子與抑炎因子轉(zhuǎn)錄與釋放,從而調(diào)控炎癥反應(yīng)[47]。

綜上所述,針刺能夠調(diào)控a7nAchR的表達(dá),激活膽堿能抗炎通路,可能通過(guò)NF-kB、JAK2/STAT3、PI3K /AKT等信號(hào)轉(zhuǎn)導(dǎo)通路抑制炎性因子與促炎因子的合成與釋放,從而調(diào)控炎癥反應(yīng)。

7 展望

膽堿能抗炎通路可以直接、迅速、高效地調(diào)節(jié)免疫功能從而起到控制炎癥的通路[48]。a7nAchR在膽堿能抗炎通路處于核心地位[14]。針刺能夠調(diào)控a7nAchR的表達(dá),激活膽堿能抗炎通路,通過(guò)NF-kB、JAK2/STAT3、PI3K/AKT等多條信號(hào)轉(zhuǎn)導(dǎo)通路抑制炎癥反應(yīng)。然而其上下游通路蛋白的表達(dá)及信號(hào)的傳遞機(jī)制仍未闡明,需要更有針對(duì)性的實(shí)驗(yàn)進(jìn)行研究探索。a7nAchR在抑制機(jī)體氧化應(yīng)激及神經(jīng)炎癥中也發(fā)揮重要的作用,在神經(jīng)保護(hù)及抑制炎癥反應(yīng)過(guò)程處于核心地位。在神經(jīng)保護(hù)及抑制炎癥反應(yīng)領(lǐng)域中,針刺調(diào)控a7nAchR的作用機(jī)制具有強(qiáng)大的臨床應(yīng)用前景,值得深入地研究[49-50]。

[1] 舒晴,陳麗,何文娟,等.針灸調(diào)控炎癥通路相關(guān)研究的回顧[J].世界針灸雜志,2016,26(2):63-69.

[2] 張瑞,郭麗紅,殷媛,等.電針對(duì)膠原誘導(dǎo)性關(guān)節(jié)炎大鼠血清中炎性細(xì)胞因子含量的影響[J].針刺研究,2016, 41(1):51-54.

[3] 石莎,殷明.煙堿型乙酰膽堿受體及其神經(jīng)保護(hù)作用[J].現(xiàn)代生物醫(yī)學(xué)進(jìn)展,2009,9(7):1350-1351, 1355.

[4] Borovikova LV, Ivanova S, Zhang M,. Vagus nerve stimulation attenuates the systemic inflammatory response to endotoxin[J]., 2000,405(6785):458- 462.

[5] Rosas-Ballina M, Tracey KJ. Cholinergic control of inflammation[J]., 2010,265(6):663-679.

[6] Narla S, Klejbor I, Birkaya B,. α7 nicotinic receptor agonist reactivates neurogenesis in adult brain[J]., 2013,86(8):1099-1104.

[7] Wu J, Lukas RJ. Naturally-expressed nicotinic acetylcho- line receptor subtypes[J]., 2011,82(8):800-807.

[8] Charpantier E, Wiesner A, Huh KH,. Alpha7 neuro- nal nicotinic acetylcholine receptors are negatively regulated by tyrosine phosphorylation and Src-family kinases[J]., 2005,25 (43):9836-9849.

[9] Albuquerque EX, Pereira EFR, Alkondon M,. Mam- malian nicotinic acetylcholine receptors: from structure to function[J]., 2009,89(1):73-120.

[10] Li S, Li Z, Pei L,. The?±7nAch-NMDA receptor complex is involved in cue-induced reinstatement of nicotine seeking[J]., 2012,209(12): 2141-2147.

[11] Hawkins BT. Modulation of cerebral microvascular permeability by endothelial nicotinic acetylcholine receptors[J].:, 2005,289(1): H212-H219.

[12] Gahring LC, Rogers SW. Neuronal nicotinic acetylcholine receptor expression and function on nonneuronal cells[J]., 2005,7(4):E885-E894.

[13] Parrish WR, Rosas-Ballina M, Gallowitsch-Puerta M,. Modulation of TNF release by choline requires alpha7 subunit nicotinic acetylcholine receptor-mediated signaling[J]., 2008,14(9-10):567.

[14] Kawashima K, Fujii T. Basic and clinical aspects of non- neuronal acetylcholine: overview of non-neuronal cholinergic systems and their biological significance[J]., 2008,106(2):167.

[15] Hawkins BT, Egleton RD, Davis TP. Modulation of cerebral microvascular permeability by endothelial nicotinic acetylcholine receptors[J]., 2005,289(1):H212.

[16] Cheng Q, Yakel JL. The effect of α7 nicotinic receptor activation on glutamatergic transmission in the hippocampus[J]., 2015,97(4): S0006295215003858.

[17] Takahashi HK, Iwagaki H, Hamano R,. Alpha7 nicotinic acetylcholine receptor stimulation inhibits lipopolysaccharide-induced interleukin-18 and -12 production in monocytes[J]., 2006, 102(1):143.

[18] Orr-Urtreger A, G?ldner FM, Saeki M,. Mice deficient in the alpha7 neuronal nicotinic acetylcholine receptor lack alpha-bungarotoxin binding sites and hippocampal fast nicotinic currents[J]., 1997,17(23):9165.

[19] Wang H, Yu M, Ochani M,. Nicotinic acetylcholine receptor alpha7 subunit is an essential regulator of inflammation[J]., 2002,421(6921):384-388.

[20] Zhao M, He X, Bi XY,. Vagal stimulation triggers peripheral vascular protection through the cholinergic anti-inflammatory pathway in a rat model of myocardial ischemia/reperfusion[J]., 2013,108 (3):345.

[21] Xiang H, Hu B, Li Z,. Dexmedetomidine controls systemic cytokine levels through the cholinergic anti- inflammatory pathway[J]., 2014,37(5): 1763-1770.

[22] Cedillo JL, Arnalich F, MartínSánchez C,. Useful- ness ofa7 nicotinic receptor messenger RNA levels in peripheral blood mononuclear cells as a marker for cholinergic anti-inflammatory pathway activity in septic patients: results of a pilot study[J]., 2015, 211(1):146-155.

[23] Rehani K, Scott DA, Renaud D,. Cotinine-induced convergence of the cholinergic and PI3 kinase-dependent anti-inflammatory pathways in innate immune cells[J].(), 2008,1783(3):375-382.

[24] Marie-Renée Blanchet, Evelyne Isra?l-Assayag, Daleau P,. Dimethyphenylpiperazinium, a nicotinic receptor agonist, downregulates inflammation in monocytes/ macrophages through PI3K and PLC chronic activation[J]., 2006, 291(4):L757-L763.

[25] de Jonge WJ, Ep VDZ, The FO,. Stimulation of the vagus nerve attenuates macrophage activation by activating the Jak2-STAT3 signaling pathway[J]., 2005,6(8):844-851.

[26] Yoshikawa H, Kurokawa M, Ozaki N,. Nicotine inhibits the production of proinflammatory mediators in human monocytes by suppression of I-kappaB phosphor- ylation and nuclear factor-kappaB transcriptional activity through nicotinic acetylcholine receptor alpha7[J]., 2010,146(1):116-123.

[27] Liu PR, Zhou Y, Zhang Y,. Electroacupuncture alleviates surgery-induced cognitive dysfunction by increasinga7-nAchR expression and inhibiting inflamm- atory pathway in aged rats[J]., 2017,659:1 -6.

[28] Wang Y, Jiang Q, Xia YY,. Involvement of α7nAchR in electroacupuncture relieving neuropathic pain in the spinal cord of rat with spared nerve injury[J]., 2018,137:257.

[29] Liu J, Li C, Peng H,. Electroacupuncture attenuates learning and memory impairment via activation ofa7nAchR-mediated anti-inflammatory activity in focal cerebral ischemia/reperfusion injured rats[J]., 2017,14(2):939-946.

[30] 胡志蘋(píng),黃志華,黃誠(chéng).a7尼古丁受體介導(dǎo)100 Hz電針調(diào)節(jié)自然殺傷細(xì)胞活性的實(shí)驗(yàn)研究[J].重慶醫(yī)學(xué), 2014,43(5):582-583.

[31] Candelario-Jalil E. Injury and repair mechanisms in ischemic stroke: considerations for the development of novel neurotherapeutics[J]., 2009,10(7):644-654.

[32] Guarini S, Altavilla D, Cainazzo MM,. Efferent vagal fibre stimulation blunts nuclear factor-kB activation and protects against hypovolemic hemorrhagic shock[J]., 2003,107(8):1189-1194.

[33] Mcnamara PJ, Murthy P, Kantores C,. Rapid disruption of axon-glial integrity in response to mild cerebral hypoperfusion[J]., 2011,31(49):18185.

[34] Zhang W, Sun Q, Gao X,. Anti-inflammation of spirocyclopiperazinium salt compound LXM-10 targeting α7 nAChR and M4 mAChR and inhibiting JAK2/STAT3 pathway in rats[J].,2013,8(6): e66895.

[35] 項(xiàng)水英.膽堿能抗炎通路在電針治療COPD大鼠中的作用研究[D].合肥:安徽中醫(yī)藥大學(xué),2018.

[36] Cai ZY, Yan Y, Chen R. Minocycline reduces astrocytic reactivation and neuroinflammation in the hippocampus of a vascular cognitive impairment rat model[J]., 2010,26(1):28-36.

[37] 曹燕.針刺治療血管性癡呆的臨床選穴規(guī)律及海馬膽堿能抗炎通路的研究[D].濟(jì)南:山東中醫(yī)藥大學(xué), 2017.

[38] 孔立紅,劉勝洪,毛娟娟,等.電針對(duì)腦缺血大鼠NF-kB及TNF-a表達(dá)的影響[J].中國(guó)康復(fù)醫(yī)學(xué)雜志,2009,24 (8):711-714.

[39] Han Z, Shen F, He Y,. Activation ofa-7 nicotinic acetylcholine receptor reduces ischemic stroke injury through reduction of pro-inflammatory macrophages and oxidative stress[J]., 2014,9(8):e105711.

[40] 周永川.a7nAchR-NF-kB信號(hào)通路在尼古丁影響人牙周膜細(xì)胞IL-1b和IL-8表達(dá)中的研究[D].西安:第四軍醫(yī)大學(xué),2012.

[41] Yoshikawa H, Kurokawa M, Ozaki N,. Nicotine inhibits the production of proinflammatory mediators in human monocytes by suppression of I-kappaB phosphor- ylation and nuclear factor-kappaB transcriptional activity through nicotinic acetylcholine receptor alpha7[J]., 2010,146(1):116-123.

[42] Yue Y, Liu R, Cheng W,. GTS-21 attenuates lipopolysaccharide-induced inflammatory cytokine production in vitro by modulating the Akt and NF-kB signaling pathway through thea7 nicotinic acetylcholine receptor[J]., 2015,29(2): 504-512.

[43] Wang Q, Wang F, Li X,. Electroacupuncture pretreatment attenuates cerebral ischemic injury througha7 nicotinic acetylcholine receptor-mediated inhibition of high-mobility group box 1 release in rats[J]., 2012,9(1):24-30.

[44] Guo H, German P, Bai S,. The PI3K/AKT pathway and renal cell carcinoma[J]., 2015,42 (7):343-353.

[45] Risso G, Blaustein M, Pozzi B,. Akt/PKB: one kinase, many modifications[J]., 2015,468(2):203- 214.

[46] 傅文垚,羅建平,劉長(zhǎng)虹.PI3K/AKT信號(hào)通路在常見(jiàn)神經(jīng)退行性疾病中的機(jī)制研究進(jìn)展[J].生物技術(shù)通訊, 2017,28(6):853-859.

[47] 萬(wàn)亞會(huì).膠質(zhì)細(xì)胞a7-nAchR/PI3K/AKT通路在小鼠慢性睡眠剝奪中的炎性作用機(jī)制研究[D].天津:天津醫(yī)科大學(xué),2018.

[48] Pavlov VA, Tracey KJ. The cholinergic anti-inflammatory pathway[J]., 2005,19(6):493- 499.

[49] 謝佳麗,劉超明,李良東,等.a7nAchR的抗炎及神經(jīng)保護(hù)作用研究進(jìn)展[J].贛南醫(yī)學(xué)院學(xué)報(bào),2017,37(3): 471-476.

[50] Parada E, Egea J, Buendia I,. The microgliala7-acetylcholine nicotinic receptor is a key element in promoting neuroprotection by inducing heme oxygenase- 1 via nuclear factor erythroid-2-related factor 2[J]., 2013,19(11):1135-1148.

Current Research on Acupuncture Regulation ofa7nAChR Activation of Cholinergic Anti-inflammatory Pathway

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The cholinergic anti-inflammatory pathway is a neuroimmune pathway. It prevents tissue damage mainly through acetylcholine binding toa7nAChR on the surface of macrophages and other cells to inhibit the synthesis and release of pro-inflammatory factors. Thea7nAChR is the main receptor for cholinergic transmitters and plays a key role in the cholinergic anti-inflammatory pathway. Acupuncture has a definite anti-inflammatory effect. Its mechanism of action may be related to regulatinga7nAChR activation of cholinergic anti-inflammatory pathway. Although scholars at home and abroad have made a lot of studies on the anti-inflammatory mechanism of acupuncture in recent years, the mechanism of anti-inflammatory action of acupuncture is now still unclear. This article analyzes and summarizes acupuncture regulation ofa7nAChR activation of cholinergic anti-inflammatory pathway from an overview of cholinergic anti-inflammatory pathway,a7nAChR structure and function,a7nAChR distribution, the role ofa7nAChR in cholinergic anti-inflammatory pathway and the mechanism of acupuncture regulation ofa7nAChR activation of cholinergic anti-inflammatory pathway so as to provide reference ideas and scientific basis for future exploration of the mechanism of anti-inflammatory action of acupuncture.

Acupuncture therapy; Acetylcholine;a7 nicotinic acetylcholine receptor; Signaling pathway;Neuroimmunomodulation

R2-03

A

10.13460/j.issn.1005-0957.2020.01.0116

1005-0957(2020)01-0116-07

2019-06-25

國(guó)家自然科學(xué)基金項(xiàng)目(81473763);黑龍江省教育廳科學(xué)技術(shù)研究項(xiàng)目重點(diǎn)項(xiàng)目(12531z010);黑龍江中醫(yī)藥大學(xué)創(chuàng)新團(tuán)隊(duì)建設(shè)項(xiàng)目(2017sit01);黑龍江中醫(yī)藥中青年科技攻關(guān)項(xiàng)目(ZQG-028);黑龍江中醫(yī)藥大學(xué)研究生創(chuàng)新科研項(xiàng)目(2018yjscx012)

王東巖(1971—),女,教授,博士、博士后導(dǎo)師,Email:doctwdy@163.com