石崯力 王旭
摘要 目的:基于生物信息學(xué)方法對(duì)糖尿病腦病(DE)的關(guān)鍵基因進(jìn)行初步篩選,探索與其相關(guān)的潛在靶點(diǎn)、生物過(guò)程及通路,進(jìn)而預(yù)測(cè)治療DE的潛在中藥。方法:運(yùn)用GEO數(shù)據(jù)庫(kù)篩選出基因芯片原始數(shù)據(jù)集GSE161355作為樣本進(jìn)行研究?;赗 Studio軟件的質(zhì)量評(píng)估和差異分析篩選差異基因,應(yīng)用DAVID數(shù)據(jù)庫(kù)進(jìn)行基因本體(GO)富集分析和京都基因和基因組百科全書(shū)(KEGG)富集分析,利用Cytoscape軟件進(jìn)行關(guān)鍵靶點(diǎn)篩選及關(guān)鍵功能模塊構(gòu)建、可視化。通過(guò)將關(guān)鍵靶點(diǎn)與Coremine Medical數(shù)據(jù)庫(kù)相互映射,篩選治療DE的潛在中藥。結(jié)果:通過(guò)對(duì)GSE161355基因原始數(shù)據(jù)集的預(yù)處理,從DE患者中篩選出326個(gè)顯著性差異基因,差異基因主要參與學(xué)習(xí)、記憶、神經(jīng)元突觸傳遞、細(xì)胞分裂、蛋白質(zhì)分泌、血管生成調(diào)節(jié)等生物過(guò)程,與神經(jīng)活性配體-受體信號(hào)通路、細(xì)胞周期通路等存在關(guān)聯(lián)。蛋白質(zhì)-蛋白質(zhì)相互作用(PPI)網(wǎng)絡(luò)顯示MCHR2、CXCR2、GNAI1、P2RY13、NPY1R、C3、LPAR4、OXTR、CHRM5、CDC7、ORC5、ORC4、CCNA1可作為治療DE的潛在靶點(diǎn),多方位、多維度、多層面參與炎癥反應(yīng)、細(xì)胞凋亡、內(nèi)質(zhì)網(wǎng)應(yīng)激、血管生成等生物過(guò)程。通過(guò)中藥預(yù)測(cè)篩選發(fā)現(xiàn)人參、熟地黃、西紅花、銀杏葉、黃連、郁金等可作為潛在來(lái)源。結(jié)論:通過(guò)對(duì)顯著性差異基因和潛在核心靶點(diǎn)的分析促進(jìn)了對(duì)DE發(fā)病機(jī)制的進(jìn)一步理解和探索,為今后治療和評(píng)估提供了新的方向和臨床依據(jù)。
關(guān)鍵詞 生物信息學(xué);糖尿病;腦病;糖尿病腦病;差異基因;作用機(jī)制;中醫(yī)治療;中藥預(yù)測(cè)
Screening of Key Genes and Pathways Related to Diabetic Encephalopathy Based on Bioinformatics and Prediction of Effective Chinese Medicinals
SHI Yinli,WANG Xu
(The First School of Clinical Medicine of Nanjing University of Chinese Medicine,The Affiliated Hospital of Nanjing University of Traditional Chinese Medicine,Nanjing 210029,China)
Abstract Objective:This study aims to screen key genes related to diabetic encephalopathy(DE),potential targets of the genes,and biological processes and pathways of the genes based on bioinformatics,and thereby predict potential effective Chinese medicinals.Methods:The microarray dataset GSE161355 was screened from Gene Expression Omnibus(GEO) for analysis.Differently expressed genes were yielded based on quality evaluation and difference analysis by R Studio,and DAVID was employed for Gene Ontology(GO) term enrichment and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment analysis.Cytoscape was applied to screen key targets and visualize key functional modules.By mapping key targets with the Coremine Medical,we screened potential Chinese medicinals for the treatment of DE,and constructed the “potential medicinal-active component-core target” network.Results:A total of 326 significantly differential genes were screened out,which were involved in the biological processes such as learning,memory,synaptic transmission of neurons,cell division,protein secretion,and angiogenesis regulation,and the pathways of neural active ligand-receptor interaction,cell cycle,and other pathways.The protein-protein interaction(PPI) network showed MCHR2,CXCR2,GNAI1,P2RY13,NPY1R,C3,LPAR4,OXTR,CHRM5,CDC7,ORC5,ORC4,and CCNA1 were potential targets against DE,which were involved in inflammation,cell apoptosis,endoplasmic reticulum stress,angiogenesis,and other biological processes from multiple aspects.Radix Ginseng,Radix Rehmanniae Preparata,Stigma Croci,F(xiàn)olium Ginkgo,Rhizoma Coptidis,and Radix Curcumae were effective medicinals,which nourish qi,blood,yin and yang,promote blood circulation,remove blood stasis,dredge collaterals,resolve phlegm,refresh the brain,and resuscitate.Conclusion:This study further clarified the pathogenesis of DE through the analysis of differentially expressed genes and potential core targets,which provides a new theoretical research direction and clinical basis for future treatment and prognosis evaluation.75F30330-E95D-4C6C-AB27-FB800CFFDFFD
Keywords Bioinformatics; Diabetes Mellitus; Encephalopathy; Diabetic encephalopathy; Differentially expressed genes; Mechanism; TCM treatment; Chinese medicinal prediction
中圖分類號(hào):R285;R587文獻(xiàn)標(biāo)識(shí)碼:Adoi:10.3969/j.issn.1673-7202.2022.08.004
糖尿病腦病(Diabetic Encephalopathy,DE)是糖尿?。―iabetes Mellitus,DM)常見(jiàn)的慢性并發(fā)癥之一,是DeJong于1950年在一例嚴(yán)重的中樞神經(jīng)系統(tǒng)異常的糖尿病患者病例中發(fā)現(xiàn),并由此創(chuàng)造“糖尿病性腦病”這一概念[1]。一項(xiàng)對(duì)230萬(wàn)人的匯總分析發(fā)現(xiàn),患有糖尿病的個(gè)體罹患癡呆的風(fēng)險(xiǎn)較正常個(gè)體要高出60%,且在女性中尤為顯著[2]。現(xiàn)代研究認(rèn)為,DE是患者處在長(zhǎng)期高糖狀態(tài)下導(dǎo)致中樞神經(jīng)系統(tǒng)的正常生理結(jié)構(gòu)和功能遭受破壞,神經(jīng)電生理和影像學(xué)出現(xiàn)異常改變(如腦組織彌漫性改變、齒狀核萎縮、軟腦膜纖維化和血管病變)的一種神經(jīng)系統(tǒng)并發(fā)癥。患者出現(xiàn)不同程度的認(rèn)知功能障礙包括學(xué)習(xí)、空間和記憶能力減退、健忘,嚴(yán)重者可進(jìn)展至不可逆性癡呆,對(duì)患者的預(yù)后產(chǎn)生不良影響[3]。DE是多成分、多靶點(diǎn)、多通路作用形成的復(fù)雜的中樞神經(jīng)系統(tǒng)疾病,目前尚無(wú)針對(duì)DE的西醫(yī)診療方案,而中醫(yī)通過(guò)辨證論治,認(rèn)為DE以痰濕、瘀血、濁毒等侵犯機(jī)體,腎氣虧損,氣血運(yùn)行不足,髓??仗?,神機(jī)失用為發(fā)病的基本病機(jī),其病位在腦,與脾、腎多臟腑密切相關(guān)。越來(lái)越多的證據(jù)表明,中醫(yī)藥可通過(guò)調(diào)控神經(jīng)細(xì)胞炎癥反應(yīng)、氧化應(yīng)激、細(xì)胞凋亡、內(nèi)質(zhì)網(wǎng)應(yīng)激等多個(gè)生理病理環(huán)節(jié)進(jìn)而起到治療DE的作用[4-6],但其具有未知性、復(fù)雜性的特點(diǎn),使得中醫(yī)藥治療DE的藥理效應(yīng)及機(jī)制的具體闡述仍有欠缺。生物信息學(xué)是將生物學(xué)、計(jì)算機(jī)信息學(xué)、網(wǎng)絡(luò)技術(shù)等多學(xué)科交叉融合的一門(mén)綜合學(xué)科[7],將生物信息學(xué)應(yīng)用于中醫(yī)藥領(lǐng)域,已成為現(xiàn)代研究的主流趨勢(shì)。通過(guò)生物信息學(xué)方法對(duì)GEO數(shù)據(jù)庫(kù)中的原始芯片數(shù)據(jù)進(jìn)行初步篩選與分析,挖掘引起DE發(fā)病的關(guān)鍵基因,并對(duì)關(guān)鍵基因的潛在生物過(guò)程與信號(hào)通路進(jìn)行分析,通過(guò)關(guān)鍵基因?qū)哂袧撛谧饔眯?yīng)的中藥進(jìn)行預(yù)測(cè),旨在揭示其復(fù)雜分子作用機(jī)制并為其進(jìn)一步研究與臨床應(yīng)用提供參考。
1 材料與方法
1.1 數(shù)據(jù)集獲取
以“diabetic encephalopathy”作為檢索詞,將種屬設(shè)置為“human sapiens”,在GEO數(shù)據(jù)庫(kù)(https://www.ncbi.nlm.nih.gov/geo/)[8]中進(jìn)行檢索。檢索后可獲得12個(gè)數(shù)據(jù)集,對(duì)其數(shù)據(jù)集的內(nèi)容進(jìn)行再次規(guī)范化篩選后,以數(shù)據(jù)集GSE161355表達(dá)譜芯片作為最終研究樣本,下載該基因表達(dá)譜芯片的表達(dá)矩陣與相關(guān)信息。
1.2 數(shù)據(jù)預(yù)處理
運(yùn)用R Studio軟件安裝“Bioconductor”[9]“affyPLM”[10]“affy”“l(fā)imma”[11]“pheatmap”和“ggplot2”[12]等相關(guān)擴(kuò)展包。調(diào)用“Bioconductor”“affyPLM”“affy”包對(duì)GSE161355表達(dá)譜芯片進(jìn)行包括質(zhì)量控制、匯總探針集數(shù)據(jù)、計(jì)算基因表達(dá)數(shù)據(jù)、擬合回歸的分析,繪制芯片相對(duì)對(duì)數(shù)表達(dá)(Relative Log Expression,RLE)箱線圖、相對(duì)標(biāo)準(zhǔn)差(Normalized Unscaled Standard Errors,NUSE)箱線圖。RLE為一個(gè)探針組在某個(gè)樣品的表達(dá)值除以該探針組在所有樣品中表達(dá)值的中位數(shù)后取對(duì)數(shù),反映了平行實(shí)驗(yàn)的一致性。NUSE為一個(gè)探針組在某個(gè)樣品的PM值的標(biāo)準(zhǔn)差除以探針值在各樣品中的PM標(biāo)準(zhǔn)差的中位數(shù),相較于RLE更為敏感,通過(guò)質(zhì)量評(píng)估給予剔除降解嚴(yán)重的不可靠樣本;利用“affy”[13]包讀取經(jīng)過(guò)質(zhì)量控制處理后GSE161355的表達(dá)譜芯片數(shù)據(jù),應(yīng)用穩(wěn)健多芯片平均標(biāo)準(zhǔn)化分析方法(Robust Mulitichip Average,RMA)對(duì)正常組樣本和DE組樣本進(jìn)行處理后合并;運(yùn)用最近鄰居法(K-nearest Neighbor,KNN)尋找原始數(shù)據(jù)的缺失值并對(duì)其進(jìn)行補(bǔ)充;運(yùn)用GPL570芯片平臺(tái)將Probe ID轉(zhuǎn)換為Gene Symbol,獲取經(jīng)預(yù)處理后的標(biāo)準(zhǔn)化基因表達(dá)值。
1.3 差異表達(dá)基因篩選
基于R Studio軟件中的“l(fā)imma”包對(duì)標(biāo)準(zhǔn)化后的GSE161355芯片表達(dá)譜進(jìn)行差異分析,通過(guò)采用貝葉斯方法進(jìn)行多重檢驗(yàn)矯正,以|log2 FC|>1,P<0.05作為顯著差異基因的篩選條件。將篩選后的結(jié)果通過(guò)“pheatmap”“ggplot2”包進(jìn)行可視化處理,以火山圖和熱圖的形式輸出。
1.4 差異基因的潛在代謝通路與生物過(guò)程分析
將獲得的顯著性差異基因(Differentially Expressed Genes,DEGs)導(dǎo)入DAVID 6.8數(shù)據(jù)庫(kù)(https://david.ncifcrf.gov/)[14],將“Gene List”及“Background”設(shè)置為“homo sapiens”?;赗 Studio軟件的“ggplot2”擴(kuò)展包進(jìn)行京都基因與基因組百科全書(shū)(Kyoto Encyclopedia of Genes and Genomes,KEGG)通路富集分析,設(shè)定閾值P<0.05;下載“dplyr”“org.Hs.eg.db”安裝包,以閾值P<0.05進(jìn)行關(guān)鍵基因基因本體(Gene Ontology,GO)富集分析,最終以條形圖和氣泡圖的形式輸出結(jié)果。
1.5 蛋白質(zhì)-蛋白質(zhì)相互作用(Protein-protein Interaction,PPI)網(wǎng)絡(luò)構(gòu)建 將獲得的顯著性差異基因?qū)隨tring數(shù)據(jù)庫(kù)(https://string-db.org/cgi/input.pl),選擇種屬為“homo sapiens”,篩選條件為“minimum required interaction score>0.9”,將得到的PPI關(guān)系導(dǎo)入Cytoscape 3.8.0軟件構(gòu)建成分靶點(diǎn)和疾病靶點(diǎn)PPI網(wǎng)絡(luò)[15],通過(guò)Degree值分析各靶點(diǎn)在PPI網(wǎng)絡(luò)中的重要程度[16];并通過(guò)分子復(fù)合檢測(cè)(Molecular Complex Detection,MCODE)插件對(duì)構(gòu)建的PPI網(wǎng)絡(luò)進(jìn)行模塊挖掘,篩選出其中關(guān)聯(lián)性強(qiáng)的PPI模塊[17]。參數(shù)設(shè)置為:degree=3,node score=0.2,k-core=2,max.Depth=100。75F30330-E95D-4C6C-AB27-FB800CFFDFFD
1.6 關(guān)鍵靶點(diǎn)對(duì)接及中藥預(yù)測(cè)
將篩選出的DEGs與DE相關(guān)的生物學(xué)過(guò)程導(dǎo)入Coremine Medical數(shù)據(jù)庫(kù)(https://www.coremine.com/)[18]中,設(shè)置閾值條件為P<0.05,由此篩選出與關(guān)鍵基因和潛在生物學(xué)過(guò)程相關(guān)的中藥。從中藥系統(tǒng)藥理學(xué)數(shù)據(jù)庫(kù)與分析平臺(tái)(Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform,TCMSP)(http://lsp.nwu.edu.cn/tcmsp.php)[19]中根據(jù)閾值口服生物利用度(Oral Bioavailability,OB)≥30%,類藥性(Drug Likeness,DL)≥0.18篩選預(yù)測(cè)中藥的潛在化學(xué)成分,并運(yùn)用Uniprot數(shù)據(jù)庫(kù)對(duì)獲得的有效靶點(diǎn)進(jìn)行去重、規(guī)范化,將處理后的數(shù)據(jù)導(dǎo)入Cytoscape 3.8.0軟件中構(gòu)建“中藥-有效成分-靶點(diǎn)”網(wǎng)絡(luò)圖,利用Cytoscape軟件中Hubba插件[20]的MCC≥3為篩選標(biāo)準(zhǔn)對(duì)排列前20的靶點(diǎn)進(jìn)行篩選并進(jìn)行可視化處理。
1.7 差異基因表達(dá)譜芯片的一般情況 該GSE161355表達(dá)譜芯片數(shù)據(jù)集來(lái)源于英國(guó)謝菲爾德大學(xué)神經(jīng)病學(xué)觀察組,是由15例健康對(duì)照者與18例糖尿病患者的神經(jīng)元、星形膠質(zhì)細(xì)胞及神經(jīng)血管內(nèi)皮細(xì)胞組成。研究者將各組受試者的顳皮層細(xì)胞從體內(nèi)提取出后在體外培養(yǎng),通過(guò)免疫定向激光的方式捕獲、顯微切割、分離神經(jīng)元、星形膠質(zhì)細(xì)胞和內(nèi)皮細(xì)胞。見(jiàn)表1。
2 結(jié)果
2.1 芯片數(shù)據(jù)質(zhì)量評(píng)估
對(duì)GSE161355表達(dá)譜芯片的原始數(shù)據(jù)進(jìn)行質(zhì)量評(píng)估,得到RLE箱線圖。結(jié)果提示,該數(shù)據(jù)集中各樣本比值接近于1,對(duì)值接近于0,整體表達(dá)水平基本趨于一致。見(jiàn)圖1。NUSE箱線圖見(jiàn)圖2,結(jié)果表明,除了GSM4905229和GSM4905233樣本,其余31個(gè)樣本的基因表達(dá)標(biāo)準(zhǔn)差基本趨于一致,由此說(shuō)明GSM4905229和GSM4905233這2個(gè)樣本質(zhì)量較差,在后續(xù)的研究中應(yīng)予以剔除。應(yīng)用RMA法預(yù)處理及匯總剔除較差樣本后的數(shù)據(jù),將芯片上的Probe ID轉(zhuǎn)化為Gene Symbol,并對(duì)數(shù)據(jù)集中存在缺失值的部分采用KNN法進(jìn)行補(bǔ)充,最終匯總獲取20 461個(gè)基因表達(dá)水平數(shù)據(jù)。
2.2 差異基因篩選結(jié)果
通過(guò)將糖尿病組樣本與對(duì)照組進(jìn)行比較,以P<0.05,|log2 FC|>1作為顯著差異基因的篩選條件,應(yīng)用R Studio軟件進(jìn)行分析,共篩選出326個(gè)DEGs,其中包含了309個(gè)表達(dá)上調(diào)基因及17個(gè)表達(dá)下調(diào)基因,表明正常個(gè)體與DE患者之間存在顯著差異性基因。所選數(shù)據(jù)集的火山圖和熱圖見(jiàn)圖3~4。
2.3 關(guān)鍵靶點(diǎn)的代謝通路與生物過(guò)程分析
將獲得的DEGs利用DAVID數(shù)據(jù)庫(kù)進(jìn)行GO分析,結(jié)果可獲得30條GO富集功能,其中生物過(guò)程(Biological Process,BP)相關(guān)的條目最多,共18條,4條細(xì)胞組分(Cellular Component,CC)和8條分子功能(Molecular Function,MF)。以P<0.05為篩選條件選取GO條目,其涉及學(xué)習(xí)、記憶、神經(jīng)元突觸傳遞、細(xì)胞分裂、蛋白質(zhì)分泌、血管生成調(diào)節(jié)等生物學(xué)過(guò)程。運(yùn)用R Studio軟件下的“ggplot2”擴(kuò)展包對(duì)上述的分析結(jié)果進(jìn)行可視化處理。見(jiàn)圖5。利用DAVID數(shù)據(jù)庫(kù)對(duì)DEGs進(jìn)行KEGG通路分析,共獲得6條富集通路,以P<0.05為篩選條件選取共4條KEGG條目。分析結(jié)果提示核心靶點(diǎn)與神經(jīng)活性配體-受體相互作用信號(hào)通路、細(xì)胞周期通路等有關(guān),與此同時(shí)還與病毒感染性疾病、寄生蟲(chóng)病、藥物使用等存在聯(lián)系。運(yùn)用R Studio軟件下的“ggplot2”擴(kuò)展包對(duì)上述的分析結(jié)果進(jìn)行可視化處理。見(jiàn)圖6。
2.4 PPI網(wǎng)絡(luò)的構(gòu)建與分析
利用String數(shù)據(jù)庫(kù)分別獲得DEGs之間的互作網(wǎng)絡(luò),設(shè)置minimum required interaction score為highest confidence(0.9),將分析結(jié)果的TSV數(shù)據(jù)通過(guò)Cytoscape 3.8.0軟件中進(jìn)行可視化,該P(yáng)PI網(wǎng)絡(luò)中具有共有節(jié)點(diǎn)36個(gè),43條邊,平均Degree值為2.38;運(yùn)用CytoNCA插件以Degree值大于中位數(shù)為標(biāo)準(zhǔn)進(jìn)行篩選出核心靶點(diǎn)13個(gè):MCHR2、CXCR2、GNAI1、P2RY13、NPY1R、C3、LPAR4、OXTR、CHRM5、CDC7、ORC5、ORC4、CCNA1;基于MCODE插件對(duì)PPI網(wǎng)絡(luò)中的關(guān)聯(lián)性較強(qiáng)的模塊進(jìn)行篩選,所得功能模塊最大者由6個(gè)節(jié)點(diǎn),15條邊組成,score為6.0,該模塊即為PPI網(wǎng)絡(luò)中緊密聯(lián)系的區(qū)域。見(jiàn)圖7。
2.5 DE相關(guān)潛在核心靶點(diǎn)與生物學(xué)過(guò)程的中藥預(yù)測(cè)
通過(guò)Coremine Medical數(shù)據(jù)庫(kù)預(yù)測(cè)具有潛在治療DE的中藥,以P<0.05作為篩選標(biāo)準(zhǔn),預(yù)測(cè)結(jié)果顯示多種中藥與NPY1R、LPAR4、OXTR、ORC5、DRD1、CDKN1A等核心靶點(diǎn)以及學(xué)習(xí)、記憶、細(xì)胞黏附、蛋白質(zhì)水解等生物學(xué)過(guò)程關(guān)系較為密切。見(jiàn)表2。其中,人參、熟地黃等有補(bǔ)氣補(bǔ)血之效,銀杏葉、西紅花等為活血化瘀通絡(luò)之藥,白果取化痰開(kāi)竅、補(bǔ)腎滋陰之功,黃連、積雪草清熱燥濕發(fā)揮降低血糖的作用,因此挑選上述中藥進(jìn)行有效成分與靶點(diǎn)的驗(yàn)證,構(gòu)建“中藥-有效成分-靶點(diǎn)”作用網(wǎng)絡(luò)。見(jiàn)圖8?;贛CC算法應(yīng)用Cytoscape軟件中的Hubba插件對(duì)前20的靶點(diǎn)進(jìn)行篩選。其中顏色的深淺代表MCC評(píng)分的高低程度。結(jié)果表明人參、黃連、白果、銀杏葉等中藥的某些有效成分如槲皮素、山柰酚、豆甾醇、異鼠李素可通干預(yù)胰島素作用、炎癥反應(yīng)、氧化應(yīng)激等多條信號(hào)通路起到治療DE的作用。見(jiàn)圖9。
3 討論75F30330-E95D-4C6C-AB27-FB800CFFDFFD
DE是屬獲得性認(rèn)知行為缺陷為特征的DM慢性并發(fā)癥之一,是由遺傳、肥胖、飲食、情緒、外部環(huán)境多種因素共同作用引起。DE的發(fā)病與糖脂代謝紊亂、胰島素作用異常、細(xì)胞凋亡、炎癥反應(yīng)、過(guò)度氧化應(yīng)激以及Tau蛋白異常磷酸化密切關(guān)聯(lián)[21]。利用生物信息學(xué)技術(shù)挖掘DE相關(guān)的基因表達(dá)譜,探索DE發(fā)生發(fā)展的潛在靶點(diǎn)與通路,尋求有效的干預(yù)中藥,為臨床研究提供了新的思路。
3.1 胰島素抵抗參與了DE的發(fā)生 胰島素抵抗(Insulin Resistance,IR)是DM和代謝綜合征發(fā)病的關(guān)鍵病理機(jī)制。長(zhǎng)期的高糖環(huán)境使得胰島B細(xì)胞對(duì)葡萄糖的攝取利用率下降,腦內(nèi)胰島素信號(hào)轉(zhuǎn)導(dǎo)出現(xiàn)異常,進(jìn)而破壞神經(jīng)遞質(zhì)系統(tǒng),引起細(xì)胞凋亡,加速β淀粉樣蛋白(Amyloid Protein,Aβ)在腦內(nèi)異常堆積,影響了發(fā)揮認(rèn)知功能的主要部位大腦組織海馬區(qū)神經(jīng)元的形態(tài)與突觸的可塑性,最終導(dǎo)致患者出現(xiàn)認(rèn)知功能缺失。海馬星形膠質(zhì)細(xì)胞可因高血糖而造成損傷,改變谷氨酸能神經(jīng)遞質(zhì)傳遞和糖酵解途徑,抑制神經(jīng)元-星形膠質(zhì)細(xì)胞之間的能量代謝偶聯(lián),導(dǎo)致細(xì)胞受到興奮性毒性影響,加速神經(jīng)元的損傷與衰老[22-23]。通過(guò)對(duì)基因譜進(jìn)行篩選發(fā)現(xiàn),DEGs主要富集于胰島素抵抗、趨化因子釋放、炎癥反應(yīng)、細(xì)胞凋亡等方面。黑色素濃集激素受體2(Melanin-concentrating Hormone Receptor 2,MCHR2)是一種存在于靈長(zhǎng)類動(dòng)物腦組織的受體,其高表達(dá)可增加肥胖與代謝紊亂的發(fā)病風(fēng)險(xiǎn),調(diào)控MCHR2可激活黑色素濃集激素,由此調(diào)節(jié)下丘腦的能量消耗使機(jī)體的能量代謝平衡處于穩(wěn)態(tài)[24]。實(shí)驗(yàn)研究發(fā)現(xiàn)調(diào)控1型神經(jīng)肽Y受體(Neuropeptide Y Receptor Type 1,NPY1R)的表達(dá)可抑制DM大鼠胰島B細(xì)胞過(guò)度分泌,改善IR,延緩認(rèn)知和記憶功能衰退[25]。溶血磷脂酸受體4(Lysophosphatidic Acid Receptor4,LPAR4)作為L(zhǎng)PA的受體亞族之一,可有選擇性地激活脂肪細(xì)胞,與Gα12/13蛋白產(chǎn)生偶聯(lián),重塑脂肪組織架構(gòu)而抑制IR[26]。KEGG分析結(jié)果表明,神經(jīng)活性配體-受體相互作用信號(hào)通路在改善IR、保護(hù)受損的神經(jīng)元方面起到了積極的作用。多巴胺D1受體(Dopamine D1 Receptor,DRD1)作為中樞神經(jīng)系統(tǒng)重要的神經(jīng)遞質(zhì),被認(rèn)為與認(rèn)知障礙的發(fā)生有關(guān)[27]。在膽堿能神經(jīng)元廣泛分布的大腦區(qū)域,縮宮素受體(Oxytocin Receptor,OXTR)過(guò)表達(dá),對(duì)改善IR、平衡能量代謝、削弱負(fù)面情緒等方面起到一定的作用[28],可作為治療DE的潛在靶點(diǎn)之一。
3.2 細(xì)胞凋亡和炎癥反應(yīng)是DE進(jìn)展的重要環(huán)節(jié)? IR不僅可以引起機(jī)體糖脂代謝紊亂,可促進(jìn)細(xì)胞凋亡和炎癥反應(yīng)發(fā)生,影響著腦內(nèi)神經(jīng)系統(tǒng)的結(jié)構(gòu)完整,阻礙神經(jīng)系統(tǒng)功能的正常發(fā)揮,導(dǎo)致一系列神經(jīng)系統(tǒng)疾病的發(fā)生。海馬區(qū)IR的發(fā)生促使了星形膠質(zhì)細(xì)胞的激化與激活,加速趨化因子、炎癥介質(zhì)的釋放,加重炎癥反應(yīng)。應(yīng)用MCODE方法對(duì)PPI網(wǎng)絡(luò)中連接緊密的潛在靶點(diǎn)進(jìn)行提取,獲得了CHRM5、IL1B、CXCR2、C3、CDKN1A、HSPB1、ILF2等涉及炎癥反應(yīng)、細(xì)胞凋亡的重要基因。CXCR2可與相應(yīng)的趨化因子配體IL-8、CXCL2、CXCL3結(jié)合激活,驅(qū)動(dòng)中性粒細(xì)胞、單核細(xì)胞、上皮細(xì)胞和巨噬細(xì)胞,其過(guò)表達(dá)可導(dǎo)致db/db小鼠加劇炎癥反應(yīng)和糖脂代謝紊亂[29]。同時(shí),C-X-C基序趨化因子受體2(C-X-C Motif Chemokine Receptor 2,CXCR2)通過(guò)核因子κB和PI3K-AKT等炎癥信號(hào)通路出現(xiàn)異位表達(dá),誘發(fā)細(xì)胞出現(xiàn)過(guò)早衰老[30]。細(xì)胞周期蛋白依賴性激酶抑制劑1(Cyclin-dependent Kinase-inhibitor 1,CDKN1A)是細(xì)胞周期調(diào)節(jié)的重要蛋白之一,通過(guò)轉(zhuǎn)錄合成相關(guān)蛋白以調(diào)控在細(xì)胞的增殖、分化、衰老和凋亡。有研究表明,CDKN1A與2型糖尿病的發(fā)病存在密切的關(guān)系,其作用機(jī)制可能與延緩過(guò)度炎癥反應(yīng)、調(diào)節(jié)血管生成和通透性相關(guān)[31]。
3.3 預(yù)測(cè)的中藥可能是治療DE的靶向藥物 中醫(yī)醫(yī)家認(rèn)為DE病程日久,或因痰蒙神竅,或因瘀血阻絡(luò),或因痰瘀毒互結(jié),均會(huì)耗損陰陽(yáng),腎精不足,髓??仗摚识啾憩F(xiàn)健忘、精神恍惚、認(rèn)知減退等。將預(yù)測(cè)出的潛在中藥進(jìn)行分類。1)補(bǔ)益藥:人參、熟地黃、蜂蜜。2)活血化瘀通絡(luò)藥:白果、西紅花、銀杏葉、姜黃、郁金、肉桂、紫堇。3)清熱祛濕,化痰開(kāi)竅藥:黃連、遠(yuǎn)志、積雪草、玉米須,各方藥互相配伍,起化腦絡(luò)瘀阻,調(diào)氣血通暢,補(bǔ)正氣虛損,調(diào)脾胃運(yùn)化功能,固護(hù)腎氣根本。實(shí)驗(yàn)研究表明人參的主要有效成分人參皂苷能干預(yù)糖脂代謝紊亂、抑制炎癥反應(yīng)和IR,通過(guò)胰島素信號(hào)通路改善海馬區(qū)Aβ的異常堆積,延緩認(rèn)知障礙進(jìn)展[32]。小檗堿作為黃連的有效成分,不僅可以通過(guò)下調(diào)晚期糖基化終末產(chǎn)物/晚期糖基化終末產(chǎn)物受體/核因子κB炎癥信號(hào)通路,減少神經(jīng)炎癥反應(yīng),保護(hù)神經(jīng)元,保護(hù)認(rèn)知缺陷[33];還可調(diào)節(jié)高脂高糖引起的腸道菌群紊亂,改善IR,對(duì)機(jī)體內(nèi)的長(zhǎng)期高血糖環(huán)境起到緩解作用[34]。銀杏葉提取物可減弱Aβ的異常沉積和tau蛋白的異常磷酸化,激活海馬區(qū)星形膠質(zhì)細(xì)胞自噬,降低腫瘤壞死因子、白細(xì)胞介素-1β等炎癥介質(zhì)的產(chǎn)生[35]。白果有效成分白果內(nèi)酯對(duì)海馬神經(jīng)元的增殖與突觸產(chǎn)生起到正向保護(hù)作用[36]。
本研究運(yùn)用生物信息學(xué)方法對(duì)數(shù)據(jù)集GSE161355表達(dá)譜芯片進(jìn)行處理與分析,結(jié)果表明DE的發(fā)生可能與神經(jīng)元突觸傳導(dǎo)、胰島素抵抗、細(xì)胞增殖、凋亡、炎癥反應(yīng)的相關(guān)機(jī)制關(guān)聯(lián),這些潛在靶點(diǎn)可能是干預(yù)DE進(jìn)展的重要因素;預(yù)測(cè)的中藥及其活性成分可作為治療DE的新藥物。但是研究仍有存在基因表達(dá)譜芯片的樣本量有限、樣本質(zhì)量不均一、分析存在偏倚誤差等不足,預(yù)測(cè)中藥對(duì)DE的治療效果還有待后續(xù)的臨床及基礎(chǔ)實(shí)驗(yàn)加以驗(yàn)證。
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(2021-04-13收稿 本文編輯:楊覺(jué)雄)
基金項(xiàng)目:國(guó)家自然科學(xué)基金項(xiàng)目(81973796)——“糖脂清”調(diào)控lncRNA-PVT1介導(dǎo)miR-106b/ATG16L/LC3通路改善糖尿病認(rèn)知障礙的作用機(jī)制研究作者簡(jiǎn)介:石崯力(1995.11—),女,碩士,醫(yī)師,研究方向:內(nèi)分泌與代謝疾病方向,E-mail:viviennne@foxmail.com通信作者:王旭(1960.10—),女,博士,教授,主任醫(yī)師,博士研究生導(dǎo)師,研究方向:內(nèi)分泌與代謝疾病方向,E-mail:njzywangxu@126.com75F30330-E95D-4C6C-AB27-FB800CFFDFFD