神經(jīng)損傷與功能重建·2019年7月·第14卷·第7期封3·《GLIA》優(yōu)秀論文推薦·

Functional

mousecortical

bicarbonate

expression

cotransporter

ofelectrogenicsodium

S255-257and

astrocytes

regulated

is

1

dependent

(NBCe1)in

bymTOR

on

*

KhakipoorS1,GiannakiM1,TheparambilSM2,ZechaJ3,KüsterB3,4,HeermannS1,DeitmerJW2,RoussaE1

mentofMolecularEmbryology,InstituteforAnatomyandCellBiology,FacultyofMedicine,

UniversityofFreiburg,Albertstrasse17,D-79104,Freiburg,Germany.

mentofNeuroanatomy,InstituteforAnatomyandCellBiology,FacultyofMedicine,Universityof

Freiburg,Albertstrasse17,D-79104,Freiburg,Germany.

mentofGeneralZoology,FBBiology,UniversityofKaiserslautern,P.B.3049,D-67653,

Kaiserslautern,Germany.

AbstractTheelectrogenicsodiumbicarbonatecotransporter1,NBCe1(SLC4A4),isthemajorbicarbonate

ghlysensitiveforbicarbonateandthemainregulatorofintracellular,

extracellular,andsynapticpH,r,despitetheseessentialfunc-

ti,themolecularmechanismsunderlyingNBCe1-mediatedastrocyticrespetoextracellularpHchanges

rimarymousecorticalastrocytecultures,weinvestigatedtheeffectoflong-termex-

tracellularmetabolicalkalosisonregulationofNBCe1andelucidatedtheunderlyingmolecularmechanismsby

immunoblotting,biotinylationofsurfaceproteins,intracellularH+recordingusingtheH+-sensitivedye2',

7'-bis-(carboxyethyl)-5-(and-6)-carboxyfluorescein,ultowedsignifi-

cantdownregulationofNBCe1activityfollowingmetabolicalkalosiswithoutinfluencingproteinabundanceor

alkalosis,therateofintracellularH+changesuponchallengingNBCe1was

decreasedinwild-typeastrocytes,sis-induced

er,massspectrometryre-

vealedctitutivelyphosphorylatedS255-257andmutationalanalysisuncoveredtheseresiduesbeingcrucial

ultsdemtrateanovelmTOR-regulatedmechanismbywhichNBCe1

chanismlikelyappliesnotonlyforNBCe1inastrocytes,butinepithe-

lialcellsaswell.

Keywordsastroglia;epilepsy;growthfactor;pH

電碳酸氫鈉協(xié)同轉(zhuǎn)運(yùn)蛋白1（NBCe1）在小鼠皮質(zhì)

星形膠質(zhì)細(xì)胞中的功能性表達(dá)依賴于S255-257

并受mTOR調(diào)節(jié)

摘要電碳酸氫鈉協(xié)同轉(zhuǎn)運(yùn)蛋白1，NBCe1（SLC4A4）是星形膠質(zhì)細(xì)胞中表達(dá)的主要碳酸氫根轉(zhuǎn)運(yùn)蛋白。它

對(duì)碳酸氫根高度敏感，并且是細(xì)胞內(nèi)、細(xì)胞外和突觸pH值的主要調(diào)節(jié)劑，從而調(diào)節(jié)神經(jīng)元興奮性。盡管已

知NBCe1的這些基本功能，然而NBCe1介導(dǎo)的星形膠質(zhì)細(xì)胞對(duì)細(xì)胞外pH值變化反應(yīng)的分子機(jī)制尚不明

確。使用原代小鼠皮質(zhì)星形膠質(zhì)細(xì)胞培養(yǎng)，本研究探索長(zhǎng)期細(xì)胞外代謝堿中毒對(duì)NBCe1調(diào)節(jié)的影響；并通

過(guò)免疫印跡，表面蛋白的生物素化，使用H+敏感染料2,7-雙（羧乙基）-5-（6）-羧基熒光素記錄細(xì)胞內(nèi)H+，和磷

酸化蛋白質(zhì)組學(xué)分析闡明該調(diào)節(jié)作用潛在的分子機(jī)制。結(jié)果顯示代謝性堿中毒后NBCe1活性顯著下調(diào)，而

NBCe1的蛋白質(zhì)豐度或表面表達(dá)并不受影響。在堿中毒期間，NBCe1活性下調(diào)時(shí)細(xì)胞內(nèi)H+變化的速率在野

生型星形膠質(zhì)細(xì)胞中降低，但在NBCe1缺陷小鼠的皮質(zhì)星形膠質(zhì)細(xì)胞中不變。激活mTOR信號(hào)傳導(dǎo)能夠拯

救堿中毒誘導(dǎo)的NBCe1活性降低。此外，質(zhì)譜分析揭示S255-257的組成型磷酸化，而突變分析揭示這些殘

基對(duì)NBCe1轉(zhuǎn)運(yùn)活性至關(guān)重要。本研究證明了一種通過(guò)調(diào)節(jié)NBCe1的功能表達(dá)而實(shí)現(xiàn)的新的mTOR調(diào)節(jié)

機(jī)制。該種機(jī)制不僅適用于星形膠質(zhì)細(xì)胞，也適用于上皮細(xì)胞中的NBCe1。

關(guān)鍵詞星形膠質(zhì)細(xì)胞；癲癇；生長(zhǎng)因子；pH值

中圖分類號(hào)R741；R741.02文獻(xiàn)標(biāo)識(shí)碼ADOI10.16780/cj.2019.07.018

（編譯：杜一星）

*摘自《Glia》,

2019,doi:

10.1002/

glia.23682.

[Epubahead

ofprint]