嚴(yán)小軍 祁鵬志 郭寶英 李繼姬

Nrf2參與水生動(dòng)物氧化應(yīng)激調(diào)控的研究進(jìn)展*

嚴(yán)小軍1, 2祁鵬志1, 2①郭寶英1, 2李繼姬1, 2

(1. 國(guó)家海洋設(shè)施養(yǎng)殖工程技術(shù)研究中心 舟山 316022; 2. 浙江海洋大學(xué)海洋科學(xué)與技術(shù)學(xué)院 舟山 316022)

環(huán)境變化會(huì)誘導(dǎo)機(jī)體活性氧(reactive oxygen species, ROS)水平升高, 從而產(chǎn)生氧化應(yīng)激。氧化應(yīng)激對(duì)所有生物的生存、生長(zhǎng)、發(fā)育和進(jìn)化都具有深遠(yuǎn)的影響。核因子E2相關(guān)因子2 (nuclear factor erythroid 2 related factor 2, Nrf2)被公認(rèn)為細(xì)胞氧化應(yīng)激調(diào)控的主導(dǎo)者, 與伴侶蛋白Kelch樣環(huán)氧氯丙烷相關(guān)蛋白1 (kelch-like ECH-associated protein 1, Keap1)一起控制數(shù)百個(gè)解毒酶和抗氧化蛋白編碼基因的表達(dá)。近年來(lái), Nrf2在水生動(dòng)物中逐漸獲得重視, 并在一些模式魚(yú)類(lèi)如斑馬魚(yú)、鯉魚(yú)及其他一些魚(yú)類(lèi)和水生無(wú)脊椎動(dòng)物中得到研究。介紹了Nrf2的結(jié)構(gòu)以及調(diào)控機(jī)制, 回顧了近年來(lái)水生動(dòng)物Nrf2通路參與氧化應(yīng)激調(diào)控所取得的進(jìn)展。研究表明, Nrf2在水生動(dòng)物中廣泛存在, 在非生物(金屬、有機(jī)污染物、無(wú)機(jī)鹽、藥物及微塑料等)、生物(細(xì)菌、病毒、有毒藻類(lèi))以及生境變化(冰融、鹽脅迫)誘導(dǎo)的氧化應(yīng)激調(diào)控中發(fā)揮重要作用。Nrf2一經(jīng)激活入核, 在小Maf蛋白的協(xié)助下與抗氧化反應(yīng)元件(antioxidant-response element, ARE)結(jié)合, 啟動(dòng)一系列ARE驅(qū)動(dòng)基因的表達(dá), 并和孕烷X受體(pregnane X receptor, Pxr)、絲裂原活化蛋白激酶(mitogen-activated protein kinase, MAPK)以及芳烴受體(aryl hydrocarbon receptor, AhR)等細(xì)胞通路協(xié)同作用參與一系列生理過(guò)程。Nrf2在水生動(dòng)物響應(yīng)環(huán)境變化過(guò)程中發(fā)揮重要的細(xì)胞保護(hù)機(jī)制, 有望發(fā)展成為抗逆育種潛在的基因靶點(diǎn)。

核因子E2相關(guān)因子2 (Nrf2); 氧化應(yīng)激; 水生動(dòng)物

細(xì)胞通過(guò)表達(dá)抗氧化蛋白和II相解毒酶來(lái)為自身提供保護(hù), 這些蛋白在低水平氧化應(yīng)激狀態(tài)下即可被激活, 而這種激活是通過(guò)被稱為抗氧化反應(yīng)元件(antioxidant-response element, ARE)或親電反應(yīng)元件(electrophilic response element, EpRE)的順式作用元件介導(dǎo)的(Kobayashi, 2005)。ARE最初發(fā)現(xiàn)于編碼人和鼠兩種主要解毒酶谷胱甘肽S轉(zhuǎn)移酶Ya (GST-Ya)和NAD(P)H醌氧化還原酶1 (Nqo1)的啟動(dòng)子區(qū)(Jaiswal, 1994), 而后來(lái)的研究發(fā)現(xiàn)ARE廣泛存在于抗氧化蛋白和II相解毒酶基因的5′啟動(dòng)子區(qū), 從轉(zhuǎn)錄水平上調(diào)控細(xì)胞保護(hù)酶對(duì)氧化脅迫的誘導(dǎo)反應(yīng)(Nguyen, 2003)。由ROS及親電體水平升高和/或抗氧化能力降低而引起的細(xì)胞氧化還原狀態(tài)的改變是觸發(fā)ARE介導(dǎo)的轉(zhuǎn)錄反應(yīng)的重要信號(hào)(Nguyen, 2009)。接下來(lái)的研究中, ARE的結(jié)合因子引起了科學(xué)家的興趣。最終, 核因子E2相關(guān)因子2 (nuclear factor erythroid 2 related factor 2, Nrf2)成為人們關(guān)注的焦點(diǎn), 被公認(rèn)為細(xì)胞抗氧化防御的主導(dǎo)者(Vomund, 2017)。

Nrf2最早是被作為p45 NF-E2密切關(guān)聯(lián)蛋白從K562細(xì)胞中克隆的(Moi, 1994)。p45 NF-E2是珠蛋白異源二聚體中較大的亞基, 具有NF-E2位點(diǎn)的結(jié)合活性, 是珠蛋白基因表達(dá)的關(guān)鍵順式調(diào)節(jié)因子(Andrews, 1993)。p45 NF-E2相關(guān)蛋白中的4個(gè)成員p45 NF-E2、Nrf1、Nrf2和Nrf3已經(jīng)在哺乳動(dòng)物中分離出來(lái), 被稱為Cap'n'collar (CNC)型堿性亮氨酸拉鏈(bZIP)蛋白(Motohashi, 2002)。這個(gè)名稱來(lái)源于與果蠅CNC蛋白的序列相似性。CNC蛋白首先在果蠅中被發(fā)現(xiàn), 是唇和下頜發(fā)育所必需的(Mohler, 1995)。CNC蛋白其中一個(gè)異構(gòu)體CNCC蛋白包含Nrf2經(jīng)典的ETGE基序, 可能發(fā)揮和脊椎動(dòng)物中Nrf2類(lèi)似的功能(Kobayashi, 2005)。Nrf2在鼠、人、雞和魚(yú)中被鑒定出來(lái), 并且被認(rèn)為可能存在于所有其他脊椎動(dòng)物中(Kobayashi, 2002), 而近年來(lái)的研究表明, Nrf2也廣泛存在于一些水生無(wú)脊椎動(dòng)物包括貝類(lèi)、蝦類(lèi)等(Silvestre, 2020), 表明Nrf2介導(dǎo)的細(xì)胞防御功能在自然界中可能是保守的。Nrf2與ARE結(jié)合, 調(diào)節(jié)ARE介導(dǎo)的抗氧化基因表達(dá)從而參與響應(yīng)環(huán)境變化的細(xì)胞反應(yīng)(Dhakshinamoorthy, 2001; Jaiswal, 2004)。Nrf2的活性調(diào)節(jié)機(jī)制表明, Kelch樣環(huán)氧氯丙烷相關(guān)蛋白1 (kelch-like ECH-associated protein 1, Keap1)是Nrf2的伴侶蛋白, 在Nrf2調(diào)控過(guò)程中發(fā)揮至關(guān)重要的作用。Keap1和Nrf2共同構(gòu)成一個(gè)二元系統(tǒng), 在人體中調(diào)控多達(dá)250個(gè)含ARE結(jié)構(gòu)的基因。Keap1-Nrf2系統(tǒng)已發(fā)展成為機(jī)體對(duì)抗環(huán)境侵害的主要防御機(jī)制, 在維持機(jī)體穩(wěn)態(tài)方面有著關(guān)鍵作用。

1 Nrf2、Keap1結(jié)構(gòu)

1.1 Nrf2結(jié)構(gòu)

Nrf2是由核因子NFE2L2 (erythroid-derived 2-like 2)編碼的蛋白, 具有堿性亮氨酸拉鏈(basic region-leucine zipper, bZIP)結(jié)構(gòu), 隸屬于CNC轉(zhuǎn)錄因子家族, 是該家族中活力最強(qiáng)的轉(zhuǎn)錄調(diào)控因子(Alam, 1999)。Nrf2廣泛存在于從低等的昆蟲(chóng)到高等的哺乳動(dòng)物中, 在持續(xù)暴露于外界環(huán)境的皮膚、肺、消化道以及解毒代謝器官如肝臟和腎臟中大量表達(dá)。

同源比對(duì)發(fā)現(xiàn)Nrf2包含7個(gè)高度保守的Neh (Nrf2-ECH homology)結(jié)構(gòu)域(圖1a)。Neh1位于Nrf2的C端, 包含bZIP基序, 能夠與多種含有此同源結(jié)構(gòu)的小Maf蛋白、c-Jun蛋白, c-Fos蛋白結(jié)合形成二聚體。細(xì)胞核內(nèi), Nrf2通過(guò)Neh1區(qū)與小Maf蛋白結(jié)合, 進(jìn)而識(shí)別并結(jié)合ARE元件, 啟動(dòng)下游基因轉(zhuǎn)錄。此外, Neh1區(qū)還包含核轉(zhuǎn)錄因子普遍的核定位和輸出信號(hào), 能夠與泛素連接酶UbcM2作用以調(diào)控Nrf2的核轉(zhuǎn)位和降解(Jain, 2005)。Neh2位于Nrf2的最末N端, 含有DLG和ETGE基序的結(jié)合位點(diǎn), 是負(fù)調(diào)控蛋白Keap1的作用靶點(diǎn)。該結(jié)構(gòu)域包含豐富的賴氨酸殘基, 可介導(dǎo)Nrf2泛素化及26S蛋白酶體的降解(McMahon, 2004)。與Keap1解耦聯(lián)的Nrf2進(jìn)入細(xì)胞核并以Nrf2-sMaf異二聚體形式與ARE結(jié)合后并不能立即啟動(dòng)下游基因的轉(zhuǎn)錄, 而是需要一類(lèi)被稱為轉(zhuǎn)錄共激活子的輔助蛋白參與。位于最末C端的Neh3和位于N端的Neh4、Neh5負(fù)責(zé)結(jié)合轉(zhuǎn)錄共激活子, 共同行使轉(zhuǎn)錄調(diào)控功能。其中, Neh3通過(guò)與解螺旋酶DNA結(jié)合蛋白6 (chromodomain helicase DNA binding protein 6, CHD6)的相互作用來(lái)協(xié)助Nrf2的順式激活(Nioi, 2005), 而Neh4和Neh5結(jié)構(gòu)域是通過(guò)與環(huán)磷酸腺苷反應(yīng)元件結(jié)合蛋白(cyclic AMP response element-binding protein, CBP)的結(jié)合, 反式激活Nrf2的表達(dá)(Katoh, 2001)。對(duì)氧化還原不敏感的Neh6含有富含絲氨酸殘基的DSGIS和DSAPGS基序, 可作為糖原合成酶激酶-3 (glycogen synthase kinase-3, GSK-3β)的磷酸化靶點(diǎn), 啟動(dòng)Kepa1非依賴的Nrf2降解(Chowdhry, 2013)。Neh7是近年來(lái)新發(fā)現(xiàn)的Nrf2結(jié)構(gòu)域, 其與視黃酸X受體α (retinoic X receptor α, RXRα)識(shí)別并結(jié)合后, 能夠抑制Nrf2的轉(zhuǎn)錄(Wang, 2013a)。

圖1 Nrf2 (a)和Keap1 (b)分子的結(jié)構(gòu)域圖示

注: Keap1-dependent degradation: Keap1-依賴型降解; Transactivation domain: 轉(zhuǎn)錄激活域; RXRα binding: RXRα結(jié)合域; DNA binding domain: DNA結(jié)合域; CUL3 association: CUL結(jié)合域; Self association: 自交聯(lián); Nrf2 association: Nrf2結(jié)合域

1.2 Keap1結(jié)構(gòu)

Keap1為隸屬于Kelch家族的多區(qū)域阻遏蛋白, 可作為氧化應(yīng)激的傳感器存在, 對(duì)Nrf2號(hào)通路起負(fù)調(diào)控作用(Kobayashi, 2006)。生理狀態(tài)下, Keap1常以二聚體形式存在, 將Nrf2錨定在胞漿中, 抑制其活動(dòng)。氨基酸序列及域功能分析發(fā)現(xiàn)Keap1包含5個(gè)不同的結(jié)構(gòu)域: 氨基末端區(qū)(NTR)、羧基末端區(qū)(CTR)、Broad復(fù)合物即tramtrack和bric-a-brac結(jié)構(gòu)域(BTB), 插入?yún)^(qū)(IVR), 六個(gè)Kelch/雙甘氨酸重復(fù)序列(DGR) (圖1b)。BTB和DGR區(qū)是主要的功能區(qū)(Kaspar, 2009)。Keap1通過(guò)BTB區(qū)交聯(lián)形成同源二聚體, 同時(shí)BTB也是Cul3 (Cillion 3)依賴性E3泛素連接酶復(fù)合物的結(jié)合位點(diǎn), 是介導(dǎo)Nrf2泛素化及蛋白降解的必要區(qū)域(Cullinan, 2004)。DGR區(qū)是Keap1與Nrf2的結(jié)合區(qū), 該區(qū)中的6個(gè)Kelch能夠形成β折疊結(jié)構(gòu)與Nrf2的Neh2區(qū)結(jié)合(Adams, 2000)。IVR區(qū)含有大量的半胱氨酸(Cys, C)殘基, 是整個(gè)蛋白的功能調(diào)節(jié)區(qū)。而Nrf2誘導(dǎo)劑也常通過(guò)修飾其中的Cys273和Cys288位點(diǎn), 干擾Nrf2泛素化從而穩(wěn)定Nrf2蛋白(Ogura, 2010)。

2 Nrf2信號(hào)通路的調(diào)控機(jī)制

盡管Nrf2的激活入核能夠誘導(dǎo)數(shù)百個(gè)具有細(xì)胞保護(hù)功能的基因的表達(dá), 從而提高機(jī)體抗氧化應(yīng)激的能力, 但Nrf2的無(wú)序激活也會(huì)對(duì)機(jī)體造成嚴(yán)重傷害。keap1缺陷型小鼠體內(nèi)Nrf2無(wú)序表達(dá), 小鼠在出生后3周內(nèi)死亡(Wakabayashi, 2003)。因此, 控制Nrf2活動(dòng)對(duì)維持細(xì)胞內(nèi)環(huán)境穩(wěn)態(tài), 保障機(jī)體健康至關(guān)重要。現(xiàn)有研究表明, Nrf2信號(hào)通路的激活主要有兩種調(diào)控方式: Keap1-依賴型調(diào)控(圖2a)和Keap1-非依賴型調(diào)控(圖2b)。

2.1 Keap1-依賴型調(diào)控

生理狀態(tài)下, 兩個(gè)Keap1蛋白以BTB區(qū)交聯(lián)形成二聚體, 同時(shí)使用該區(qū)域與Cul3相互作用。二聚體Keap1的兩個(gè)DGR分別與Nrf2的Neh2結(jié)構(gòu)域的DLG和ETGE基序結(jié)合將Nrf2限制在胞漿中。Nrf2泛素化后被26S蛋白酶體降解以維持在較低的基礎(chǔ)水平, 并以從頭合成的方式更新(Stewart, 2003)。一小部分入核的Nrf2激活細(xì)胞保護(hù)基因的轉(zhuǎn)錄, 滿足機(jī)體正常的抗氧化需求。

Keap1含有27個(gè)Cys殘基, 因此常將該分子視作內(nèi)源性以及環(huán)境氧化應(yīng)激信號(hào)的傳感器(Sihvola, 2017)。ROS氧化硫醇, 誘導(dǎo)大分子谷胱甘肽(GSH)化和烷基化, 因此具有修飾Keap1 Cys的能力(Holland, 2008)。Nrf2的Keap1-依賴型調(diào)控都是以Keap1的Cys修飾為基礎(chǔ)的。一旦暴露于親電體和ROS, Keap1的某些Cys殘基(主要是C273和C288)被修飾, 導(dǎo)致Keap1構(gòu)象改變, Keap1處于一個(gè)非功能性封閉狀態(tài)。盡管Nrf2的DLG和ETGE基序能夠與Keap1的DGR結(jié)合, 但不能夠被泛素化蛋白酶體降解, 因此沒(méi)有足夠的處于游離狀態(tài)的Keap1產(chǎn)生。導(dǎo)致新生產(chǎn)的Nrf2不能被Keap1捕獲而發(fā)生入核激活(Baird, 2013)。另外還有一種“鉸鏈和閂鎖”模型。認(rèn)為Nrf2的DLG基序?qū)eap1的親和力比ETGE基序弱的多, 導(dǎo)致親電體攻擊Keap1的Cys時(shí), DLG與Keap1 DGR區(qū)的結(jié)合會(huì)斷開(kāi), 使Nrf2不能被泛素化降解, 從而發(fā)生入核轉(zhuǎn)移(Jung, 2010)。Keap1抑制的另一個(gè)機(jī)制與它與Nrf2泛素化所需的CUL3復(fù)合物的相互作用有關(guān)。位于BTB結(jié)構(gòu)域的C151影響Keap1與Cul3的結(jié)合。Nrf2激活劑巴多索隆(CDDO, RTA401)與Keap1在C151位點(diǎn)形成加合物, 從而破壞Keap1和Cul3之間的相互作用(Naidu, 2018), Keap1被阻塞在Nrf2結(jié)合構(gòu)象中, 新合成的Nrf2逃脫泛素化從而產(chǎn)生入核激活(Robledinos-Antón, 2019)。入核后的Nrf2與小Maf蛋白(MafK, MafG, MafF)結(jié)合后識(shí)別ARE序列并啟動(dòng)下游基因轉(zhuǎn)錄(Yamamoto, 2018)。

圖2 Nrf2信號(hào)通路的調(diào)控機(jī)制: (a) Keap1-依賴型調(diào)控和(b) Keap1-非依賴型調(diào)控

注: Keap1-dependent modulation: Keap1-依賴型調(diào)控; Keap1-independent modulation: Keap1-非依賴型調(diào)控; Basal state: 基態(tài); Induced state:誘導(dǎo)態(tài); Inducers: 誘導(dǎo)物; blocking: 阻斷; proteasome 26S: 蛋白酶體26S; Nrf2 degradation: Nrf2降解; Nascent Nrf2: 新生Nrf2; Cytoprotective genes: 細(xì)胞保護(hù)基因; Cytoplasm: 細(xì)胞質(zhì); Nucleus: 細(xì)胞核

2.2 Keap1-非依賴性調(diào)控

糖原合酶激酶-3β (glycogen synthase kinase-3, GSK-3β)被認(rèn)為參與Nrf2入核激活后的調(diào)控。GSK-3β蛋白激酶是一種多功能絲氨酸/蘇氨酸激酶, 在多種信號(hào)通路中發(fā)揮重要作用(Kannoji, 2008)。GSK-3β能夠磷酸化酪氨酸激酶Fyn的某個(gè)蘇氨酸(Thr, T)殘基, 介導(dǎo)Fyn的入核激活(Dai, 2017)。激活的Fyn磷酸化Nrf2的酪氨酸(Tyr, Y)568殘基, 誘導(dǎo)Nrf2的核輸出, 并被Keap1捕獲后降解(Jain, 2006)。另外, 在胞漿中GSK-3β能夠直接磷酸化Nrf2位于Neh6區(qū)的絲氨酸(Ser, S)335和338殘基, 而后磷酸化的Nrf2易位到細(xì)胞核中, 并被E3泛素連接酶β-TrCP (β-transducin repeat containing E3 ubiquitin protein ligase, β-TrCP)直接識(shí)別, 誘導(dǎo)Nrf2的核泛素化和降解(Hayes, 2015)。除此之外, 一種競(jìng)爭(zhēng)機(jī)制也會(huì)影響Nrf2對(duì)下游基因轉(zhuǎn)錄的激活。堿性亮氨酸拉鏈轉(zhuǎn)錄因子1 (basic leucine zipper transcrip-tion factor 1, Bach1)是機(jī)體內(nèi)一種廣泛存在轉(zhuǎn)錄抑制子(Sun, 2002), 和Nrf2有一定的親緣關(guān)系(Kobayashi, 2006)。生理狀態(tài)下, Bach1和小sMaf蛋白形成異二聚體并與ARE元件結(jié)合(Dhakshinamoorthy, 2005), 抑制基因表達(dá)。氧化應(yīng)激時(shí), Bach1從ARE中釋放出來(lái)并被Nrf2取代。Bach1與Nrf2競(jìng)爭(zhēng)與ARE的結(jié)合, 導(dǎo)致Nrf2下游基因的抑制(Jain, 2005)。

3 Nrf2信號(hào)通路參與水生動(dòng)物氧化應(yīng)激調(diào)控

在長(zhǎng)期的進(jìn)化過(guò)程中, 水生動(dòng)物發(fā)展了相對(duì)完善的細(xì)胞應(yīng)激體系以應(yīng)對(duì)復(fù)雜的生存環(huán)境。在哺乳動(dòng)物中發(fā)現(xiàn)的一些典型細(xì)胞應(yīng)激信號(hào)通路, 如絲裂原活化蛋白激酶(MAPK)通路, 核因子-κB (NF-κB)通路, 過(guò)氧化物酶體增殖物激活受體(PPAR)通路以及Nrf2通路等在水生動(dòng)物中也被發(fā)現(xiàn), 而Nrf2通路在其中發(fā)揮核心作用(Silvestre, 2020)。

3.1 Nrf2與環(huán)境污染相關(guān)性研究

金屬作為水系統(tǒng)中最常見(jiàn)的污染物, 對(duì)其研究最早也最為深入。在水生動(dòng)物中, Nrf2已被報(bào)道參與多種金屬誘導(dǎo)的氧化應(yīng)激反應(yīng)(表1)。而斑馬魚(yú)作為一種水生模式生物, 在Nrf2抗氧化應(yīng)激調(diào)控研究中發(fā)揮了引領(lǐng)作用。鎘是一種嗅覺(jué)毒物, 誘導(dǎo)斑馬魚(yú)抗氧化基因谷胱甘肽硫轉(zhuǎn)移酶pi (GSTpi)、谷氨酸半胱氨酸連接酶催化亞基(GCLC)、血紅素氧化酶1 (HO-1)、過(guò)氧化物酶1 (Prdx1)表達(dá), 但被嗎啉代介導(dǎo)的Nrf2敲降阻斷, 導(dǎo)致嗅覺(jué)驅(qū)動(dòng)行為破壞、細(xì)胞死亡增加和嗅覺(jué)感覺(jué)神經(jīng)元丟失。嗅覺(jué)神經(jīng)元特異性基因在Nrf2嗎啡啉突變體斑馬魚(yú)中表達(dá)下調(diào)。用Nrf2的激活劑蘿卜硫素(SFN)預(yù)處理胚胎, 可減弱鎘誘導(dǎo)的嗅覺(jué)組織損傷(Wang, 2013b)。環(huán)境相關(guān)濃度的鉻(2 mg/L)脅迫下, 斑馬魚(yú)肝臟中Nrf2在mRNA及酶活水平上均顯著上調(diào), 免疫組化證實(shí)其發(fā)生了入核激活。Nrf2的激活誘導(dǎo)下游Nqo1和含銅和鋅的超氧化物歧化酶(CuZnSOD)表達(dá)(Shaw, 2019)。紫草堿可以減輕鉻誘導(dǎo)的斑馬魚(yú)肝細(xì)胞毒性, 其最終也是通過(guò)激活Nrf2-Keap1-ARE通路, 誘導(dǎo)細(xì)胞保護(hù)基因紅細(xì)胞衍生核因子2樣蛋白2 (Fe2l2)、Nqo1和熱激蛋白70 (Hsp70)的表達(dá), 提高細(xì)胞活力, 減少ROS產(chǎn)生來(lái)實(shí)現(xiàn)的(Shaw, 2020)。另外, Shaw等(2019) 研究還發(fā)現(xiàn)作為芳烴受體(AhR)通路中重要成分的細(xì)胞色素P4501亞族A多肽(CYP1A)在鉻暴露后也顯著表達(dá)上調(diào), 作者認(rèn)為這可能是通過(guò)Nrf2依賴的AhR通路間接誘導(dǎo)的, 表明細(xì)胞抗氧化機(jī)制的組成部分之間存在廣泛的串話。類(lèi)似的交互作用機(jī)制也在研究斑馬魚(yú)銀和鎘暴露時(shí)被發(fā)現(xiàn)(Hu, 2019)。在野生型斑馬魚(yú)胚胎中, 銀和鎘的積累和毒性受三磷酸腺苷結(jié)合盒(ABC)轉(zhuǎn)運(yùn)體的影響, 可以顯著誘導(dǎo)ABC轉(zhuǎn)運(yùn)體的mRNA表達(dá), 而孕烷X受體(Pxr)和Nrf2的突變降低了這些誘導(dǎo)效應(yīng), 但ABC轉(zhuǎn)運(yùn)蛋白基礎(chǔ)表達(dá)的升高彌補(bǔ)了誘導(dǎo)性缺失。Pxr缺陷胚胎中金屬離子的毒性未變, 然而, Nrf2的突變破壞了GSH的產(chǎn)生, 導(dǎo)致銀和鎘在斑馬魚(yú)胚胎中的毒性增強(qiáng)。此外, 在未進(jìn)行攻毒的Pxr缺陷模型中, 其他轉(zhuǎn)錄因子如Ahr1b、Ppar-β、Nrf2表達(dá)均出現(xiàn)上調(diào), 而Ahr1b、Ppar-β和Pxr的誘導(dǎo)增強(qiáng)僅在金屬離子暴露的Nrf2缺陷胚胎中可見(jiàn), 說(shuō)明對(duì)轉(zhuǎn)錄因子缺失的不同補(bǔ)償現(xiàn)象。

表1 Nrf2參與水生動(dòng)物氧化應(yīng)激調(diào)控

續(xù)表

續(xù)表

在斑馬魚(yú)中, Nrf2近年來(lái)也被報(bào)道參與除金屬以外的其他多種環(huán)境污染物包括PAHs、POPs、無(wú)機(jī)鹽、藥物等的氧化應(yīng)激調(diào)控過(guò)程(表1)。氟化鈉(NaF)暴露時(shí), 斑馬魚(yú)腦和肝臟中Nrf2表達(dá)上調(diào), 而Keap1表達(dá)下調(diào), 同時(shí)下游細(xì)胞氧化應(yīng)激基因表達(dá)上調(diào), 證實(shí)了Nrf2在NaF誘導(dǎo)的斑馬魚(yú)氧化應(yīng)激中發(fā)揮重要作用, 且與哺乳動(dòng)物中經(jīng)典的Keap1負(fù)調(diào)控Nrf2的方式相吻合(Mukhopadhyay, 2015a, b)。在三氧化二砷(As2O3)暴露的斑馬魚(yú)中, Nrf2也以同樣的方式在腦中激活, 誘導(dǎo)下游HO-1和Nqo1表達(dá)上調(diào), 參與抗三氧化二砷誘導(dǎo)的氧化應(yīng)激過(guò)程(Sarkar, 2014)。叔丁基過(guò)氧化氫(tBOOH)以及α-、β-萘黃酮(ANF, BNF)單獨(dú)或者ANF+BNF聯(lián)合暴露時(shí), 斑馬魚(yú)胚胎中SOD、GSTpi、谷胱甘肽過(guò)氧化物酶(GPx)以及谷氨酰半胱氨酸連接酶(GCL)表達(dá)顯著上調(diào)。當(dāng)用嗎啉代將Nrf2敲降后, 這些元件表達(dá)上調(diào)被明顯抑制, 且使得tBOOH暴露后的斑馬魚(yú)胚胎死亡率增加, 并加劇ANF+BNF聯(lián)合暴露導(dǎo)致的胚胎畸形(Timme-Laragy, 2009)。全氟辛烷磺?；衔?PFOS)暴露明顯上調(diào)Nrf2和下游HO-1的表達(dá)。當(dāng)與Nrf2的激活劑SFN共暴露時(shí), ROS水平明顯下降。當(dāng)用嗎啉代將Nrf2沉默后, PFOS誘導(dǎo)的HO-1表達(dá)明顯下調(diào)(Shi, 2010)。高劑量的亞砷酸鈉暴露下, Nrf2突變型Nrf2afh318(Nrf2 DNA結(jié)合區(qū)域發(fā)生突變)幼斑馬魚(yú)死亡率明顯高于野生型。亞砷酸鈉暴露誘導(dǎo)細(xì)胞應(yīng)激保護(hù)因子GCLC、GSTpi、ABCC2以及Prdx1以Nrf2依賴的方式表達(dá), 而SFN預(yù)處理顯著提高亞砷酸鹽暴露時(shí)的斑馬魚(yú)成活率, Nrf2在對(duì)抗急性亞砷酸鈉毒性中發(fā)揮重要作用(Fuse, 2016)。

在除斑馬魚(yú)之外的其他魚(yú)類(lèi)中, 也有證據(jù)表明Nrf2參與細(xì)胞應(yīng)激, 是觸發(fā)抗氧化級(jí)聯(lián)反應(yīng)的關(guān)鍵事件之一。在建鯉中, 0.60 mg/L銅暴露4 d增加魚(yú)腦Nrf2核積累, 誘導(dǎo)下游抗氧化元件CuZnSOD、GPx1a、GR表達(dá)上調(diào)。增強(qiáng)Nrf2與ARE結(jié)合的能力, 導(dǎo)致CuZnSOD表達(dá)水平升高。銅暴露還上調(diào)了Nrf2、MafG1和蛋白激酶C (PKC)的表達(dá), 表明這些蛋白需要重新合成, 以延長(zhǎng)對(duì)抗氧化基因的誘導(dǎo)時(shí)效(Jiang, 2014)。在建鯉肌肉中呈現(xiàn)了與之相反的結(jié)果。0.56 mg/L銅暴露4 d導(dǎo)致魚(yú)肌肉中核Nrf2蛋白水平降低, ARE結(jié)合能力減弱, 半胱氨酸蛋白酶-3 (caspase-3)介導(dǎo)的DNA斷裂增加, 誘導(dǎo)抗氧化元件CuZnSOD、GPx1a、GPx1b表達(dá)下調(diào), 抗氧化酶活性降低從而引起肌肉的氧化損傷(Jiang, 2015)。這些研究表明即使同種污染對(duì)魚(yú)體不同組織造成的傷害也不盡相同, 魚(yú)體不同組織對(duì)同種污染誘導(dǎo)的氧化應(yīng)激可能發(fā)展出了不同的應(yīng)對(duì)機(jī)制。盡管如此, 這些研究仍證實(shí)Nrf2在魚(yú)體應(yīng)對(duì)急性Cu污染事件中發(fā)揮重要調(diào)控作用。在虹鱒中還發(fā)現(xiàn), 頭腎中Nrf2介導(dǎo)的抗氧化系統(tǒng)和PXR介導(dǎo)的解毒系統(tǒng)協(xié)同作用以對(duì)抗2,2',4,4'-四溴聯(lián)苯醚(BDE-47)誘導(dǎo)的氧化壓力(Liu, 2019)。此外, 在草魚(yú)應(yīng)對(duì)鋅(Song, 2017)和姜黃素(Ming, 2020), 大黃魚(yú)應(yīng)對(duì)鋅(Zheng, 2016)和汞(Zeng, 2016), 鰕虎魚(yú)應(yīng)對(duì)阿司匹林(Wang, 2020b)等事件中, 均能發(fā)現(xiàn)Nrf2信號(hào)通路的身影。

無(wú)脊椎動(dòng)物缺乏脊椎動(dòng)物那樣獲得性的細(xì)胞應(yīng)激機(jī)制, 機(jī)體防御反應(yīng)僅依靠非特異的固有調(diào)控機(jī)制, 其應(yīng)對(duì)外部刺激的機(jī)體反應(yīng)逐漸得到重視。近年來(lái), Nrf2在一些無(wú)脊椎動(dòng)物中逐漸被發(fā)現(xiàn), 并報(bào)道在機(jī)體抗外界刺激誘導(dǎo)的氧化應(yīng)激中發(fā)揮重要作用。低濃度鎘暴露會(huì)引起背角無(wú)齒蚌腎臟中Nrf2表達(dá)上調(diào)同時(shí)Keap1表達(dá)下調(diào), 而高濃度鎘暴露下, Nrf2表達(dá)水平無(wú)明顯變化, Keap1表達(dá)明顯下調(diào)(井維鑫, 2019)。在克氏原螯蝦中, 鎘暴露顯著降低四氫大麻酚(THC)和酚氧化酶原(proPO)水平, 而ROS水平以時(shí)間和劑量依賴的方式升高。同時(shí)鎘暴露明顯提升p38絲裂原活化蛋白激酶(p38MAPK)和Nrf2的表達(dá)和激活, 且p38MAPK和Nrf2表達(dá)與proPO活性密切相關(guān), 肝胰臟可能通過(guò)ROS介導(dǎo)的MAPK/Nrf2途徑參與氧化還原活動(dòng)(Wei, 2020)。叔丁基對(duì)苯二酚(tBHQ)作為Nrf2的激活劑, 處理太平洋牡蠣后, GR mRNA和蛋白水平上調(diào), 證實(shí)其誘導(dǎo)作用可能是通過(guò)Nrf2途徑產(chǎn)生。太平洋牡蠣Keap1和Nrf2蛋白的保守結(jié)構(gòu)域以及經(jīng)典N(xiāo)rf2誘導(dǎo)劑tBHQ對(duì)相關(guān)抗氧化防御的明確誘導(dǎo), 支持了雙殼類(lèi)Nrf2/Keap1通路與哺乳動(dòng)物中功能相一致的觀點(diǎn)(Danielli, 2017a)。苯并芘(Bap)處理菲律賓蛤仔后, 在第1天和第6天, Nrf2的轉(zhuǎn)錄水平顯著提高, 且與Keap1呈現(xiàn)負(fù)相關(guān), 與抗氧化元件GST、SOD、GPx和CAT的轉(zhuǎn)錄表達(dá)呈現(xiàn)正相關(guān)。RNAi將Nrf2敲低后, 抗氧化元件表達(dá)呈現(xiàn)與Nrf2一致的變化。與對(duì)照組相比, 脂質(zhì)過(guò)氧化水平明顯升高。結(jié)果表明, Keap1能夠感知氧化應(yīng)激, 與Nrf2組成經(jīng)典的二元系統(tǒng)在雙殼貝類(lèi)對(duì)Bap應(yīng)激調(diào)控事件中發(fā)揮作用(Wang, 2018a)。這一觀點(diǎn)在作者對(duì)另外一種雙殼貝類(lèi)櫛孔扇貝的研究中得以強(qiáng)化。另外, 在苯并芘處理櫛孔扇貝后, 除抗氧化元件外, PKC、c-JNK和p38MAPK也呈現(xiàn)與Nrf2一致的表達(dá)變化, PKC、MAPKs以及Nrf2通路在雙殼動(dòng)物抗Bap氧化防御中可能發(fā)揮協(xié)同的作用機(jī)制(Wang, 2019a)。本團(tuán)隊(duì)在厚殼貽貝中也證實(shí)Nrf2參與Bap的氧化應(yīng)激調(diào)控過(guò)程。Bap暴露顯著上調(diào)Nrf2轉(zhuǎn)錄表達(dá), 同時(shí)下游抗氧化元件SOD、CAT、GPx和GR轉(zhuǎn)錄及蛋白表達(dá)上調(diào), Nrf2與抗氧化基因轉(zhuǎn)錄表達(dá)呈現(xiàn)正相關(guān)。Nrf2原核表達(dá)后注射厚殼貽貝, 導(dǎo)致Bap誘導(dǎo)的ROS和脂質(zhì)過(guò)氧化水平比對(duì)照組顯著降低(Qi, 2020)。在矮小擬鏢水蚤內(nèi), 還發(fā)現(xiàn)納米和微米級(jí)苯丙乙烯微球能夠誘導(dǎo)細(xì)胞內(nèi)ROS的升高, 并激活Nrf2信號(hào)通路, 上調(diào)GPx、GR、SOD和GST酶活水平, 減輕細(xì)胞氧化應(yīng)激反應(yīng)(Jeong, 2017)。

3.2 Nrf2與微生物脅迫相關(guān)性研究

在哺乳動(dòng)物中的大量研究已經(jīng)證實(shí), 作為應(yīng)激狀態(tài)下最重要的細(xì)胞防御通路, Nrf2在包括嗜血桿菌(Lugade, 2011)、肺炎鏈球菌(Gomez, 2016)、結(jié)核分歧桿菌(Rothchild, 2019), 以及肝炎病毒(Ivanov, 2011; Schaedler, 2010)、甲型流感病毒(Kosmider, 2012)、水皰性口炎病毒(Olagnier, 2017)在內(nèi)的多種病原微生物的感染中發(fā)揮著重要作用。微生物感染可誘導(dǎo)機(jī)體產(chǎn)生大量的ROS, 改變正常的氧化應(yīng)激狀態(tài)。在此情況下, Nrf2信號(hào)通路被激活, 一方面誘導(dǎo)下游抗氧化基因表達(dá)以增強(qiáng)對(duì)ROS的清除, 維持細(xì)胞內(nèi)環(huán)境穩(wěn)態(tài); 另一方面與免疫信號(hào)通路如TNF-α、NF-κB等協(xié)同作用, 通過(guò)誘導(dǎo)抗炎, 抗細(xì)胞凋亡基因的表達(dá)增強(qiáng)整體的免疫耐受能力。Nrf2單獨(dú)參與水產(chǎn)動(dòng)物抗菌應(yīng)激的研究尚未見(jiàn)報(bào)道, 現(xiàn)有研究多涉及Nrf2參與其他物質(zhì)誘導(dǎo)的抗菌調(diào)控過(guò)程。Jiang等(2016)報(bào)道, 嗜水氣單胞菌能夠誘導(dǎo)建鯉氧化應(yīng)激。與肌醇攝入處于最優(yōu)水平的建鯉相比, 肌醇攝入過(guò)少或過(guò)多的魚(yú)體頭腎和脾臟中Nrf2及下游抗氧化元件包括CuZnSOD、MnSOD、CAT、GPx1a和GR的轉(zhuǎn)錄表達(dá)均受到抑制。適宜劑量的肌醇攝入會(huì)通過(guò)激活Nrf2和E2F轉(zhuǎn)錄因子4 (E2F4)介導(dǎo)的通路上調(diào)抗氧化基因的表達(dá), 促進(jìn)損傷細(xì)胞更新來(lái)應(yīng)對(duì)嗜水氣單胞菌誘導(dǎo)的氧化應(yīng)激, 促進(jìn)機(jī)體健康。在草魚(yú)中同樣發(fā)現(xiàn)適宜水平的肌醇補(bǔ)充能在草魚(yú)受到嗜水氣單胞菌脅迫時(shí)顯著下調(diào)Keap1的表達(dá), 同時(shí)上調(diào)Nrf2的表達(dá), 從而激活Nrf2信號(hào)通路, 降低ROS水平, 提高抗氧化酶活性, 增強(qiáng)其抗氧化能力(胡凱等, 2019)。這些研究證明Nrf2在肌醇補(bǔ)充誘導(dǎo)的抗細(xì)菌感染能力提升過(guò)程中發(fā)揮重要作用, 此外, 一些益生菌類(lèi)細(xì)菌也可通過(guò)Nrf2通路發(fā)揮作用。Yu等(2018)報(bào)道了異育銀鯽飲食中凝結(jié)芽孢桿菌的適量補(bǔ)充可以激活Nrf2-Keap1通路, 上調(diào)抗氧化元件如NADPH氧化酶2 (Nox2)和過(guò)氧化物酶2 (Prx2)表達(dá)水平, 增強(qiáng)抗氧化反應(yīng), 提高生長(zhǎng)性能。

盡管Nrf2已被廣泛證實(shí)參與哺乳動(dòng)物病毒感染過(guò)程, 但關(guān)于其在水生動(dòng)物病毒感染中的作用卻鮮有報(bào)道。盡管如此, 近年來(lái)的一些研究已確證實(shí)Nrf2在水生動(dòng)物病毒感染過(guò)程中發(fā)揮關(guān)鍵性作用。鯉春病毒血癥病毒(SVCV)感染黑頭軟口鰷上皮瘤細(xì)胞(EPC)細(xì)胞后, Nrf2的核蛋白和總蛋白含量以及轉(zhuǎn)錄水平均提升明顯, 表明SVCV感染能激活Nrf2, 增加其基因轉(zhuǎn)錄和蛋白表達(dá), 導(dǎo)致在細(xì)胞核內(nèi)的累積。Nrf2的激活劑2-氰基-3,12-二氧代齊墩果-1,9(11)-二烯-28-羧酸(CDDO-Me)對(duì)EPC中Nrf2的激活效應(yīng)有限, 而萊菔硫烷(SFN)能顯著增加Nrf2的核轉(zhuǎn)運(yùn), 上調(diào)下游效應(yīng)基因的表達(dá), 提高的總抗氧化能力。但介導(dǎo)的激活對(duì)SVCV的復(fù)制無(wú)顯著性影響(楊毅, 2014)。SFN和CDDO-Me刺激胖頭鯉肌肉細(xì)胞系(FHM)可以激活Nrf2-ARE 信號(hào)通路, 提高細(xì)胞總抗氧核能力。當(dāng)FHM受到SVCV感染時(shí), SFN和CDDO-Me預(yù)處理可以極顯著降低SVCV-G的轉(zhuǎn)錄水平, 降低病毒滴度, 抑制 SVCV的復(fù)制。當(dāng)Nrf2被敲降后, Nrf2蛋白表達(dá)和轉(zhuǎn)錄水平受到明顯抑制, 且廢除兩種激活劑對(duì)Nrf2-ARE信號(hào)通路的激活作用(邵軍輝, 2016)。這些研究表明Nrf2的激活有利于機(jī)體降低病毒誘導(dǎo)的氧化應(yīng)激, 維持細(xì)胞穩(wěn)態(tài), 對(duì)病毒的感染發(fā)揮抵抗性作用。但在白斑綜合征病毒(WSSV)感染日本囊對(duì)蝦過(guò)程中, Nrf2發(fā)揮的作用與之相反。WSSV感染引起對(duì)蝦血細(xì)胞內(nèi)ROS水平升高, 導(dǎo)致的Nrf2的mRNA表達(dá)以及細(xì)胞核中的蛋白水平表達(dá)上升。將Nrf2敲低后, 對(duì)蝦體內(nèi)病毒蛋白的復(fù)制受到抑制, 同時(shí)存活率明顯上升。注射SFN后, Nrf2表達(dá)量上升的同時(shí)病毒蛋白的表達(dá)量也上升。進(jìn)一步研宄發(fā)現(xiàn), WSSV結(jié)構(gòu)蛋白VP41B前端具有ARE元件, 可與Nrf2結(jié)合。敲低Nrf2可以抑制VP41B的表達(dá), 而SFN處理則增強(qiáng)其表達(dá), 而RNA干擾實(shí)驗(yàn)證實(shí)VP41B與WSSV復(fù)制相關(guān)。這些結(jié)果說(shuō)明WSSV可以利用對(duì)蝦的Nrf2-ARE系統(tǒng)啟動(dòng)自身含有ARE元件的基因的表達(dá), 進(jìn)而促進(jìn)病毒復(fù)制(陳敬, 2018)。

在軟體動(dòng)物如翡翠貽貝、褶紋冠蚌中還發(fā)現(xiàn)Nrf2參與有害藻類(lèi)及藻毒素誘導(dǎo)的氧化應(yīng)激反應(yīng)。利馬原甲藻短期暴露導(dǎo)致翡翠貽貝鰓中Keap1、CAT以及ABC轉(zhuǎn)運(yùn)蛋白轉(zhuǎn)錄表達(dá)上調(diào), 而GPx1和Nqo1表達(dá)下調(diào), 鰓明顯損傷。隨著暴露時(shí)間延長(zhǎng), Nrf2表達(dá)顯著上調(diào), 而KEAP1下調(diào), 同時(shí)Nqo1、SOD、GST-ω和ABCB1上調(diào), 96h后鰓損傷恢復(fù)。作者認(rèn)為利馬原甲藻可能導(dǎo)致鰓的氧化損傷。然而, 長(zhǎng)時(shí)間高密度暴露可激活Nrf2信號(hào)通路, 從而降低毒素對(duì)貽貝鰓組織的影響(He, 2019)。Nrf2在褶紋冠蚌的外套膜、閉殼肌、腮、血淋巴、肝胰臟各組織中都均有表達(dá), 且在肝胰臟中表達(dá)最高。微囊藻毒素刺激后, 肝胰腺和血淋巴中Nrf2表達(dá)上調(diào), 顯示Nrf2通路被激活(王曉波, 2018)。Wu等(2020)也發(fā)現(xiàn)微囊藻毒素會(huì)誘導(dǎo)褶紋冠蚌肝胰腺中Nrf2轉(zhuǎn)錄水平升高, 而下游抗氧化元件MnSOD、CuZnSOD、SeGPx和GST等轉(zhuǎn)錄及蛋白表達(dá)均上調(diào), 認(rèn)為Nrf2通路對(duì)保護(hù)軟體動(dòng)物免受微囊藻毒素侵害至關(guān)重要。

3.3 Nrf2與生境變化相關(guān)性研究

近年來(lái)研究表明, Nrf2也與一些魚(yú)類(lèi)特殊的生境適應(yīng)相關(guān)聯(lián)。側(cè)紋南極魚(yú)胚胎發(fā)育的最后階段正值海冰融化和輻射強(qiáng)度增加, 微藻群落的釋放和光合作用過(guò)程的激活提高了氧濃度, 而大量的溶解有機(jī)物和無(wú)機(jī)營(yíng)養(yǎng)鹽發(fā)生光解反應(yīng), 生成羥基自由基和過(guò)氧化氫, 此時(shí)側(cè)紋南極魚(yú)不可避免地遭受氧化壓力的威脅(Regoli, 2014)。Giuliani等(2017)研究發(fā)現(xiàn)與溫帶物種Nrf2相比, 側(cè)紋南極魚(yú)Nrf2蛋白序列顯示出對(duì)催化功能所必需的氨基酸的高度保守性, 但在非必需區(qū)域出現(xiàn)了一些特定取代, 這可能代表了一種分子適應(yīng)性, 以提高在低溫下活性位點(diǎn)的靈活性和可變性。另外, 在孵化前期Nrf2表達(dá)與胚胎發(fā)育初期相比明顯上調(diào), 其調(diào)控的抗氧化元件如CAT、GST、SeGPx也出現(xiàn)轉(zhuǎn)錄及翻譯水平的上調(diào), 證實(shí)了Nrf2在南極洲早期生命階段抗冰融化應(yīng)激保護(hù)過(guò)程中的重要性。Nrf2也被證實(shí)在抗鹽脅迫中發(fā)揮重要角色, 例如在鳳鱭中發(fā)現(xiàn)了一個(gè)Nrf2介導(dǎo)的鹽應(yīng)激調(diào)控網(wǎng)絡(luò)(Wang, 2019b)。當(dāng)鳳鱭遭受鹽脅迫時(shí), Nrf2在鰓、腦、腸和腎四種被認(rèn)為主要的滲透調(diào)節(jié)器官(Laverty, 2012)中被激活, 與水通道蛋白1 (AQP1)協(xié)同作用參與滲透調(diào)節(jié)過(guò)程。此時(shí), 下游抗氧化酶SOD、GPx被激活以應(yīng)對(duì)鹽脅迫誘導(dǎo)的氧化壓力。另外, Nrf2還通過(guò)刺激溶菌酶活性和提高白細(xì)胞計(jì)數(shù)來(lái)觸發(fā)免疫增強(qiáng)作用以應(yīng)對(duì)鹽脅迫可能帶來(lái)的免疫水平下降。

4 水生動(dòng)物Nrf2研究存在的問(wèn)題及展望

ROS的持續(xù)產(chǎn)生是水生動(dòng)物應(yīng)對(duì)外源脅迫時(shí)一個(gè)非常普遍的效應(yīng)。非生物的水污染以及生物的細(xì)菌、病毒都會(huì)誘導(dǎo)機(jī)體ROS的過(guò)多累積, 從而導(dǎo)致氧化應(yīng)激。盡管在水生動(dòng)物中已經(jīng)深入研究了參與抗氧化反應(yīng)的主要酶, 但對(duì)其關(guān)鍵調(diào)控途徑的理解還遠(yuǎn)未完成。Nrf2通路被認(rèn)為是細(xì)胞氧化應(yīng)激最主要的防御機(jī)制, 無(wú)論是在成體還是在胚胎發(fā)生過(guò)程中, 各種外源刺激都可以破壞細(xì)胞的氧化通道并觸發(fā)Nrf2途徑。當(dāng)前Nrf2通路在水生動(dòng)物中的研究大多聚焦于模式魚(yú)類(lèi), 如斑馬魚(yú)和鯉魚(yú), 在其他魚(yú)類(lèi)和水生非脊椎動(dòng)物中所涉不多。僅有的一些研究也多集中于Nrf2的鑒定, 以及對(duì)其能夠參與抗氧化應(yīng)激調(diào)控這樣粗淺的認(rèn)識(shí)。對(duì)Nrf2通路各種成分之間高水平的相互作用, 及其與其他抗氧化機(jī)制聯(lián)合激活一個(gè)復(fù)雜的細(xì)胞應(yīng)激調(diào)控網(wǎng)絡(luò)還遠(yuǎn)未涉及。接下來(lái), 應(yīng)加深水生動(dòng)物Nrf2調(diào)控異源物暴露詳細(xì)路徑及與其他通路如MAPK、AhR等協(xié)同作用的研究, 這不僅可以提供有關(guān)污染物作用方式(mode of action, MOA)的新線索, 而且還有助于開(kāi)發(fā)高通量方法來(lái)評(píng)估生態(tài)毒理風(fēng)險(xiǎn)。另外, 這些問(wèn)題的深入研究也可增進(jìn)對(duì)水生動(dòng)物響應(yīng)外界脅迫應(yīng)激調(diào)控機(jī)制的理解, 為制定水生動(dòng)物資源可持續(xù)開(kāi)發(fā)利用對(duì)策提供新思路。

王曉波, 2018. 褶紋冠蚌Nrf2和MafK基因的表達(dá)與功能分析. 南昌: 南昌大學(xué)碩士學(xué)位論文

井維鑫, 2019. 亞慢性鎘脅迫背角無(wú)齒蚌的氧化應(yīng)激與機(jī)制研究. 太原: 山西大學(xué)博士學(xué)位論文

楊 毅, 2014. EPC抗氧化應(yīng)激通路Nrf2/ARE對(duì)鯉春病毒的響應(yīng). 武漢: 華中農(nóng)業(yè)大學(xué)碩士學(xué)位論文

陳 敬, 2018. Nrf2-ARE通路在白斑綜合征病毒感染中的作用與機(jī)制研究. 濟(jì)南: 山東大學(xué)碩士學(xué)位論文

邵軍輝, 2016. 靶向于Nrf2-ARE信號(hào)的抗鯉春病毒血癥病毒研究. 武漢: 華中農(nóng)業(yè)大學(xué)碩士學(xué)位論文

胡 凱, 李雙安, 馮 琳等, 2019. 肌醇對(duì)嗜水氣單胞菌致生長(zhǎng)期草魚(yú)頭腎和脾臟氧化損傷的保護(hù)作用. 水產(chǎn)學(xué)報(bào), 43(10): 2256—2267

Adams J, Kelso R, Cooley L, 2000. The kelch repeat superfamily of proteins: propellers of cell function. Trends in Cell Biology, 10(1): 17—24

Alam J, Stewart D, Touchard C, 1999. Nrf2, a Cap’n’Collar transcription factor, regulates induction of the heme oxygenase-1 gene. Journal of Biological Chemistry, 274(37): 26071—26078

Andrews N C, Erdjument-Bromage H, Davidson M B, 1993. Erythroid transcription factor NF-E2 is a haematopoietic-specific basic-leucine zipper protein. Nature 362(6422): 722—728

Baird L, Llères D, Swift S, 2013. Regulatory flexibility in the Nrf2-mediated stress response is conferred by conformational cycling of the Keap1-Nrf2 protein complex. Proceedings of the National Academy of Sciences of the United States of America, 110(38): 15259—15264

Bao S, Nie X P, Ou R K, 2017. Effects of diclofenac on the expression of Nrf2 and its downstream target genes in mosquito fish (). Aquatic Toxicology, 188: 43—53

Breimer L H, 1990. Molecular mechanisms of oxygen radical carcinogenesis and mutagenesis: the role of DNA base damage. Molecular Carcinogenesis, 3(4): 188—197

Chen X M, Wang Q J, Guo Z X, 2020. Identification of thein the fathead minnow muscle cell line: role for a regulation in response to H2O2induced the oxidative stress in fish cell. Fish Physiology and Biochemistry, 46(5): 1699—1711

Chowdhry S, Zhang Y, McMahon M, 2013. Nrf2 is controlled by two distinct β-TrCP recognition motifs in its Neh6 domain, one of which can be modulated by GSK-3 activity. Oncogene, 32(32): 3765—3781

Costa-Silva D G, Lopes A R, Martins I K, 2018. Mancozeb exposure results in manganese accumulation and Nrf2-related antioxidant responses in the brain of common carp. Environmental Science and Pollution Research, 25(16): 15529—15540

Cullinan S B, Gordan J D, Jin J P, 2004. The Keap1-BTB protein is an adaptor that bridges Nrf2 to a Cul3-based E3 ligase: oxidative stress sensing by a Cul3-Keap1 ligase. Molecular and Cellular Biology, 24(19): 8477—8486

Dai X Z, Yan X Q, Zeng J, 2017. Elevating CXCR7 improves angiogenic function of EPCs via Akt/GSK-3β/Fyn-mediated Nrf2 activation in diabetic limb ischemia. Circulation Research, 120(5): e7—e23

Danielli N M, Trevisan R, Mello D F, 2017a. Contrasting effects of a classic Nrf2 activator,-butylhydroquinone, on the glutathione-related antioxidant defenses in Pacific oysters,. Marine Environmental Research, 130: 142—149

Danielli N M, Trevisan R, Mello D F, 2017b. Upregulating Nrf2-dependent antioxidant defenses in Pacific oysters: Investigating the Nrf2/Keap1 pathway in bivalves. Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology, 195: 16—26

Dhakshinamoorthy S, Jain A K, Bloom D A, 2005. Bach1 competes with Nrf2 leading to negative regulation of the antioxidant response element (ARE)-mediated NAD(P)H:quinone oxidoreductase 1 gene expression and induction in response to antioxidants. Journal of Biological Chemistry, 280(17): 16891—16900

Dhakshinamoorthy S, Long II D J, Jaiswal A K, 2001. Antioxidant regulation of genes encoding enzymes that detoxify xenobiotics and carcinogens. Current Topics in Cellular Regulation, 36: 201—216

Fuse Y, Nguyen V T, Kobayashi M, 2016. Nrf2-dependent protection against acute sodium arsenite toxicity in zebrafish. Toxicology and Applied Pharmacology, 305: 136—142

Giuliani M E, Benedetti M, Nigro M, 2017. Nrf2 and regulation of the antioxidant system in the Antarctic silverfish,: adaptation to environmental changes of pro-oxidant pressure. Marine Environmental Research, 129: 1—13

Giuliani M E, Regoli F, 2014. Identification of the Nrf2-Keap1 pathway in the European eel: role for a transcriptional regulation of antioxidant genes in aquatic organisms. Aquatic Toxicology, 150: 117—123

Gomez J C, Dang H, Martin J R, 2016. Nrf2 modulates host defense duringin mice. The Journal of Immunology, 197(7): 2864—2879

Hayes J D, Chowdhry S, Dinkova-Kostova A T, 2015. Dual regulation of transcription factor Nrf2 by Keap1 and by the combined actions of β-TrCP and GSK-3. Biochemical Society Transactions, 43(4): 611—620

He Z B, Duan G F, Liang C Y, 2019. Up-regulation of Nrf2-dependent antioxidant defenses inafter exposed to. Fish & Shellfish Immunology, 90: 173—179

Holland R, Hawkins A E, Eggler A L, 2008. Prospective type 1 and type 2 disulfides of Keap1 protein. Chemical Research in Toxicology, 21(10): 2051—2060

Hu J, Tian J J, Zhang F, 2019. Pxr- and Nrf2- mediated induction of ABC transporters by heavy metal ions in zebrafish embryos. Environmental Pollution, 255: 113329

Ivanov A V, Smirnova O A, Ivanova O N, 2011. Hepatitis C virus proteins activate NRF2/ARE pathway by distinct ROS-dependent and independent mechanisms in HUH7 cells. PLoS One, 6(9): e24957

Jain A K, Bloom D A, Jaiswal A K, 2005. Nuclear import and export signals in control of Nrf2. Journal of Biological Chemistry, 280(32): 29158—29168

Jain A K, Jaiswal A K, 2006. Phosphorylation of tyrosine 568 controls nuclear export of Nrf2. Journal of Biological Chemistry, 281(17): 12132—12142

Jaiswal A K, 1994. Antioxidant response element. Biochemical Pharmacology, 48(3): 439—444

Jaiswal A K, 2004. Nrf2 signaling in coordinated activation of antioxidant gene expression. Free Radical Biology and Medicine, 36(10): 1199—1207

Jeong C B, Kang H M, Lee M C, 2017. Adverse effects of microplastics and oxidative stress-induced MAPK/Nrf2 pathway-mediated defense mechanisms in the marine copepod. Scientific Reports, 7: 41323

Jia Z L, Cen J, Wang J B, 2019. Mechanism of isoniazid-induced hepatotoxicity in zebrafish larvae: Activation of ROS-mediated ERS, apoptosis and the Nrf2 pathway. Chemosphere, 227: 541—550

Jiang W D, Hu K, Liu Y, 2016. Dietary-inositol modulates immunity through antioxidant activity and the Nrf2 and E2F4/cyclin signalling factors in the head kidney and spleen following infection of juvenile fish with. Fish & Shellfish Immunology, 49: 374—386

Jiang W D, Liu Y, Hu K, 2014. Copper exposure induces oxidative injury, disturbs the antioxidant system and changes the Nrf2/ARE (CuZnSOD) signaling in the fish brain: protective effects of-inositol. Aquatic Toxicology, 155: 301—313

Jiang W D, Liu Y, Jiang J, 2015. Copper exposure induces toxicity to the antioxidant system via the destruction of Nrf2/ARE signaling and caspase-3-regulated DNA damage in fish muscle: amelioration by-inositol. Aquatic Toxicology, 159: 245—255

Jung K A, Kwak M K, 2010. The Nrf2 system as a potential target for the development of indirect antioxidants. Molecules, 15(10): 7266—7291

Kannoji A, Phukan S, Sudher Babu V, 2008. GSK3β: a master switch and a promising target. Expert Opinion on Therapeutic Targets, 12(11): 1443—1455

Kaspar J W, Niture S K, Jaiswal A K, 2009. Nrf2:INrf2 (Keap1) signaling in oxidative stress. Free Radical Biology and Medicine, 47(9): 1304—1309

Katoh Y, Itoh K, Yoshida E, 2001. Two domains of Nrf2 cooperatively bind CBP, a CREB binding protein, and synergistically activate transcription. Genes to Cells, 6(10): 857—868

Kobayashi M, Itoh K, Suzuki T, 2002. Identification of the interactive interface and phylogenic conservation of the Nrf2-Keap1 system. Genes to Cells, 7(8): 807—820

Kobayashi M, Yamamoto M, 2005. Molecular mechanisms activating the Nrf2-Keap1 pathway of antioxidant gene regulation. Antioxidants & Redox Signaling, 7(3/4): 385—394

Kobayashi M, Yamamoto M, 2006. Nrf2-Keap1 regulation of cellular defense mechanisms against electrophiles and reactive oxygen species. Advances in Enzyme Regulation, 46(1): 113—140

Kosmider B, Messier E M, Janssen W J, 2012. Nrf2 protects human alveolar epithelial cells against injury induced by influenza A virus. Respiratory Research, 13(1): 43

Laverty G, Skadhauge E, 2012. Adaptation of teleosts to very high salinity. Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 163(1): 1—6

Legradi J, Di Paolo C, Kraak M H S, 2018. An ecotoxicological view on neurotoxicity assessment. Environmental Sciences Europe, 30(1): 46

Liu C C, Wang B Y, Zhou B, 2019. The responses ofcoping with BDE-47 stress via PXR-mediated detoxification and Nrf2-mediated antioxidation system. Aquatic Toxicology, 207: 63—71

Lugade A A, Vethanayagam R R, Nasirikenari M, 2011. Nrf2 regulates chronic lung inflammation and B-cell responses to nontypeable. American Journal of Respiratory Cell and Molecular Biology, 45(3): 557—565

McMahon M, Thomas N, Itoh K, 2004. Redox-regulated turnover of Nrf2 is determined by at least two separate protein domains, the redox-sensitive Neh2 degron and the redox-insensitive Neh6 degron. Journal of Biological Chemistry, 279(30): 31556—31567

Meneghini R, 1997. Iron homeostasis, oxidative stress, and DNA damage. Free Radical Biology and Medicine, 23(5): 783—792

Ming J H, Ye J Y, Zhang Y X, 2020. Optimal dietary curcumin improved growth performance, and modulated innate immunity, antioxidant capacity and related genes expression of NF-κB and Nrf2 signaling pathways in grass carp () after infection with. Fish & Shellfish Immunology, 97: 540—553

Mohler J, Mahaffey J W, Deutsch E, 1995. Control of Drosophila head segment identity by the bZIP homeotic gene cnc. Development, 121(1): 237—247

Moi P, Chan K, Asunis I, 1994. Isolation of NF-E2-related factor 2 (Nrf2), a NF-E2-like basic leucine zipper transcriptional activator that binds to the tandem NF-E2/AP1 repeat of the beta-globin locus control region. Proceedings of the National Academy of Sciences of the United States of America, 91(21): 9926—9930

Mondal P, Shaw P, Bandyopadhyay A, 2019. Mixture effect of arsenic and fluoride at environmentally relevant concentrations in zebrafish () liver: expression pattern of Nrf2 and related xenobiotic metabolizing enzymes. Aquatic Toxicology, 213: 105219

Motohashi H, O’Connor T, Katsuoka F, 2002. Integration and diversity of the regulatory network composed of Maf and CNC families of transcription factors. Gene, 294(1/2): 1—12

Mukhopadhyay D, Priya P, Chattopadhyay A, 2015a. Sodium fluoride affects zebrafish behaviour and alters mRNA expressions of biomarker genes in the brain: role of Nrf2/Keap1. Environmental Toxicology and Pharmacology, 40(2): 352—359

Mukhopadhyay D, Srivastava R, Chattopadhyay A, 2015b. Sodium fluoride generates ROS and alters transcription of genes for xenobiotic metabolizing enzymes in adult zebrafish () liver: expression pattern of Nrf2/Keap1 (INrf2). Toxicology Mechanisms and Methods, 25(5): 364—373

Naidu S D, Muramatsu A, Saito R, 2018. C151 in KEAP1 is the main cysteine sensor for the cyanoenone class of NRF2 activators, irrespective of molecular size or shape. Scientific Reports, 8: 8037

Nguyen T, Nioi P, Pickett C B, 2009. The Nrf2-antioxidant response element signaling pathway and its activation by oxidative stress. Journal of Biological Chemistry, 284(20): 13291—13295

Nguyen T, Sherratt P J, Pickett C B, 2003. Regulatory mechanisms controlling gene expression mediated by the antioxidant response element. Annual Review of Pharmacology and Toxicology, 43: 233—260

Nioi P, Nguyen T, Sherratt P J, 2005. The carboxy-terminal Neh3 domain of Nrf2 is required for transcriptional activation. Molecular and Cellular Biology, 25(24): 10895—10906

Ogura T, Tong K I, Mio K, 2010. Keap1 is a forked-stem dimer structure with two large spheres enclosing the intervening, double glycine repeat, and C-terminal domains. Proceedings of the National Academy of Sciences of the United States of America, 107(7): 2842—2847

Olagnier D, Lababidi R R, Hadj S B, 2017. Activation of Nrf2 signaling augments vesicular stomatitis virus oncolysis via autophagy-driven suppression of antiviral immunity. Molecular Therapy, 25(8): 1900—1916

Qi P Z, Tang Z R, 2020. The Nrf2 molecule trigger antioxidant defense against acute benzo(a)pyrene exposure in the thick shell mussel. Aquatic Toxicology, 226: 105554

Regoli F, Giuliani M E, 2014. Oxidative pathways of chemical toxicity and oxidative stress biomarkers in marine organisms. Marine Environmental Research, 93: 106—117

Robledinos-Antón N, Fernández-Ginés R, Manda G, 2019. Activators and inhibitors of NRF2: a review of their potential for clinical development. Oxidative Medicine and Cellular Longevity, 2019: 9372182

Rodriguez-Brito B, Li L L, Wegley L, 2010. Viral and microbial community dynamics in four aquatic environments. The ISME Journal, 4(6): 739—751

Rothchild A C, Olson G S, Nemeth J, 2019. Alveolar macrophages generate a noncanonical NRF2-driven transcriptional response toin vivo. Science Immunology, 4(37): eaaw6693

Sarkar S, Mukherjee S, Chattopadhyay A, 2014. Low dose of arsenic trioxide triggers oxidative stress in zebrafish brain: expression of antioxidant genes. Ecotoxicology and Environmental Safety, 107: 1—8

Schaedler S, Krause J, Himmelsbach K, 2010. Hepatitis B virus induces expression of antioxidant response element-regulated genes by activation of Nrf2. Journal of Biological Chemistry, 285(52): 41074—41086

Shaw P, Mondal P, Bandyopadhyay A, 2019. Environmentally relevant concentration of chromium activates Nrf2 and alters transcription of related XME genes in liver of zebrafish. Chemosphere, 214: 35—46

Shaw P, Sen A, Mondal P, 2020. Shinorine ameliorates chromium induced toxicity in zebrafish hepatocytes through the facultative activation of Nrf2-Keap1-ARE pathway. Aquatic Toxicology, 228: 105622

Shi X J, Zhou B S, 2010. The role of Nrf2 and MAPK pathways in PFOS-induced oxidative stress in zebrafish embryos. Toxicological Sciences, 115(2): 391—400

Sihvola V, Levonen A L, 2017. Keap1 as the redox sensor of the antioxidant response. Archives of Biochemistry and Biophysics, 617: 94—100

Silvestre F, 2020. Signaling pathways of oxidative stress in aquatic organisms exposed to xenobiotics. Journal of Experimental Zoology Part A: Ecological and Integrative Physiology, 333(6): 436—448

Song C Y, Liu B, Xu P, 2019. Emodin ameliorates metabolic and antioxidant capacity inhibited by dietary oxidized fish oil through PPARs and Nrf2-Keap1 signaling in Wuchang bream (). Fish & Shellfish Immunology, 94: 842—851

Song Z X, Jiang W D, Liu Y, 2017. Dietary zinc deficiency reduced growth performance, intestinal immune and physical barrier functions related to NF-κB, TOR, Nrf2, JNK and MLCK signaling pathway of young grass carp (). Fish & Shellfish Immunology, 66: 497—523

Stewart D, Killeen E, Naquin R, 2003. Degradation of transcription factor Nrf2 via the ubiquitin-proteasome pathway and stabilization by cadmium. Journal of Biological Chemistry, 278(4): 2396—2402

Sun J Y, Hoshino H, Takaku K, 2002. Hemoprotein Bach1 regulates enhancer availability of heme oxygenase-1 gene. The EMBO Journal, 21(19): 5216—5224

Tang J, Jia X Y, Gao N N, 2018. Role of the Nrf2-ARE pathway in perfluorooctanoic acid (PFOA)-induced hepatotoxicity in. Environmental Pollution, 238: 1035—1043

Timme-Laragy A R, Van Tiem L A, Linney E A, 2009. Antioxidant responses and NRF2 in synergistic developmental toxicity of PAHs in zebrafish. Toxicological Sciences, 109(2): 217—227

Vineetha V P, Devika P, Prasitha K, 2021.ameliorated titanium dioxide nanoparticle-induced toxicity via regulating oxidative stress-activated MAPK and NRF2/Keap1 signaling pathways in Nile tilapia (). Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology, 240: 108908

Vomund S, Sch?fer A, Parnham M J, 2017. Nrf2, the master regulator of anti-oxidative responses. International Journal of Molecular Sciences, 18(12): 2772

Wakabayashi N, Itoh K, Wakabayashi J, 2003.-null mutation leads to postnatal lethality due to constitutive Nrf2 activation. Nature Genetics, 35(3): 238—245

Wang C H, Huang W H, Lin J B, 2020a. Triclosan-induced liver and brain injury in zebrafish () via abnormal expression of miR-125 regulated by PKCα/Nrf2/p53 signaling pathways. Chemosphere, 241: 125086

Wang H D, Pan L Q, Si L J, 2018a. The role of Nrf2-Keap1 signaling pathway in the antioxidant defense response induced by PAHs in the calm. Fish & Shellfish Immunology, 80: 325—334

Wang H D, Pan L Q, Xu R Y, 2019a. The molecular mechanism of Nrf2-Keap1 signaling pathway in the antioxidant defense response induced by BaP in the scallop. Fish & Shellfish Immunology, 92: 489—499

Wang H Y, Liu K H, Geng M, 2013a. RXRα inhibits the NRF2-ARE signaling pathway through a direct interaction with the Neh7 domain of NRF2. Cancer Research, 73(10): 3097—3108

Wang L, Gallagher E P, 2013b. Role of Nrf2 antioxidant defense in mitigating cadmium-induced oxidative stress in the olfactory system of zebrafish. Toxicology and Applied Pharmacology, 266(2): 177—186

Wang L L, Song X R, Song L S, 2018b. The oyster immunity. Developmental & Comparative Immunology, 80: 99—118

Wang M Y, Zhu Z X, 2019b. Nrf2 is involved in osmoregulation, antioxidation and immunopotentiation inunder salinity stress. Biotechnology & Biotechnological Equipment, 33(1): 1453—1463

Wang Y M, Wang C, Bao S, 2020b. Responses of the Nrf2/Keap1 signaling pathway in(.) exposed to environmentally relevant concentration aspirin. Environmental Science and Pollution Research, 27(13): 15663—15673

Wei K Q, Yang J X, Song C X, 2020. The responses of prophenoloxidase and MAPK/Nrf2 pathway to cadmium stress in red swamp crayfish. Marine and Freshwater Behaviour and Physiology, 53(2): 59—72

Wu J L, Liu W X, Wen C G, 2020. Effect of microcystin on the expression of Nrf2 and its downstream antioxidant genes from. Aquatic Toxicology, 225: 105526

Xie J J, He X S, Fang H H, 2020. Identification of heme oxygenase-1 from golden pompano () and response of Nrf2/HO-1 signaling pathway to copper-induced oxidative stress. Chemosphere, 253: 126654

Yamamoto M, Kensler T W, Motohashi H, 2018. The KEAP1-NRF2 System: a thiol-based sensor-effector apparatus for maintaining redox homeostasis. Physiological Reviews, 98(3): 1169—1203

Yu X L, Wu Y M, Deng M, 2019. Tetracycline antibiotics as PI3K inhibitors in the Nrf2-mediated regulation of antioxidative stress in zebrafish larvae. Chemosphere, 226: 696—703

Yu Y B, Wang C H, Wang A M, 2018. Effects of various feeding patterns ofon growth performance, antioxidant response and Nrf2-Keap1 signaling pathway in juvenile gibel carp (). Fish & Shellfish Immunology, 73: 75—83

Yu Z, Quan Y N, Huang Z Q, 2020a. Monitoring oxidative stress, immune response, Nrf2/NF-κB signaling molecules ofliving in BFT system and exposed to waterborne ammonia. Ecotoxicology and Environmental Safety, 205: 111161

Yu Z, Zheng Y G, Du H L, 2020b. Bioflocs protects copper-induced inflammatory response and oxidative stress inDybowski through inhibiting NF-κB and Nrf2 signaling pathways. Fish & Shellfish Immunology, 98: 466—476

Zeng L, Zheng J L, Wang Y H, 2016. The role of Nrf2/Keap1 signaling in inorganic mercury induced oxidative stress in the liver of large yellow croaker. Ecotoxicology and Environmental Safety, 132: 345—352

Zhao Z X, Xie J, Liu B, 2017. The effects of emodin on cell viability, respiratory burst and gene expression of Nrf2-Keap1 signaling molecules in the peripheral blood leukocytes of blunt snout bream (). Fish & Shellfish Immunology, 62: 75—85

Zheng J L, Zeng L, Shen B, 2016. Antioxidant defenses at transcriptional and enzymatic levels and gene expression of Nrf2-Keap1 signaling molecules in response to acute zinc exposure in the spleen of the large yellow croaker. Fish & Shellfish Immunology, 52: 1—8

THE ADVANCES IN RESEARCH OF Nrf2 PATHWAY INVOLVED IN OXIDATIVE STRESS REGULATION IN AQUATIC ANIMALS

YAN Xiao-Jun1, 2, QI Peng-Zhi1, 2, GUO Bao-Ying1, 2, LI Ji-Ji1, 2

(1. National Engineering Research Center of Marine Facilities Aquaculture, Zhoushan 316022, China; 2. School of Ocean Science and Technology, Zhejiang Ocean University, Zhoushan 316022, China)

Environmental changes can induce the increase of reactive oxygen species (ROS) level, which leads to oxidative stress. Oxidative stress has a profound impact on the survival, growth, development, and evolution of all organisms. The nuclear factor erythroid 2 related factor 2 (Nrf2) has been recognized as a dominant regulator of oxidative stress. Together with Kelch-like ECH associated protein 1 (Keap1), Nrf2 controls the expression of hundreds of detoxification enzymes and antioxidant protein coding genes. In recent years, Nrf2 has been gained with more and more attention in aquatic animal study, and has been studied in some model fish such as zebrafish, carp, other fish, and aquatic invertebrates. In this paper, the structure and regulatory mechanism of Nrf2 is introduced, and the progress of Nrf2 pathway involved in the regulation of oxidative stress in aquatic animals in recent years is reviewed. Studies have shown that Nrf2 exists widely in aquatic animals, and plays an important role in the regulation of oxidative stress induced by abiotic (metals, organic pollutants, inorganic salts, drugs and micro plastics), biological (bacteria, viruses, toxic algae), and habitat changes (ice melting, salt stress). Once Nrf2 is activated into the nucleus, it binds with anti-oxidant response element (ARE) with the help of small Maf protein, and starts the expression of a series of are driven genes, and interacts with pregnane X receptor (Pxr), mitogenactivated protein kinase (MAPK), and aromatic hydrocarbon receptor (AhR) and other cellular pathways are involved in a series of physiological processes. Nrf2 plays an important role in cell protection of aquatic animals in response to environmental changes, and is expected to become a potential gene target for stress resistance breeding.

nuclear factor erythroid 2 related factor 2; oxidative stress; aquatic animals

* 國(guó)家自然科學(xué)基金項(xiàng)目, 42020104009號(hào), 41976111號(hào), 42076119號(hào); 舟山市科技計(jì)劃項(xiàng)目, 2020C21119號(hào), 2019F12004號(hào)。嚴(yán)小軍, 博士生導(dǎo)師, 教授, E-mail: yanxiaojun2019@sina.com, yanxj@zjou.edu.cn

祁鵬志, 博士, 副研究員, E-mail: qpz2004@vip.sina.com, qipengzhi@zjou.edu.cn

2020-11-22,

2020-12-29

Q599; Q789; X17

10.11693/hyhz20201100316