基于网络药理学、单细胞转录分析及分子对接探讨枸杞多糖参与视神经再生的潜在机制

Potential mechanisms of Lycium barbarum polysaccharides in optic nerve regeneration based on network pharmacology, single-cell transcriptomic analysis, and molecular docking

  • 摘要:
    目的 通过整合网络药理学、单细胞转录组学及分子对接等方法,系统探讨枸杞多糖(LBPs)参与视神经再生(ONR)的潜在机制。
    方法 系统梳理LBPs的单糖组成,利用中药系统药理学数据库与分析平台(TCMSP)、SwissTargetPrediction及SuperPred数据库预测其各单糖组分的潜在作用靶点,并从在线人类孟德尔遗传数据库(OMIM)和GeneCards数据库中检索ONR相关疾病靶点。借助蛋白质相互作用关系检索工具数据库(STRING)构建交集靶点的蛋白-蛋白相互作用(PPI)网络,利用Cytoscape软件构建“药物-疾病-靶点”调控网络。基于Metascape平台开展基因本体论(GO)及京都基因与基因组百科全书(KEGG)通路富集分析,以揭示LBPs调控ONR的潜在信号通路。利用Seurat软件解析基因表达综合数据库(GEO)中的小鼠视网膜单细胞转录组数据(GSE137398),评估PPI网络核心靶点在不同视网膜细胞亚群中的表达分布特征及细胞异质性。采用分子对接技术验证LBPs核心单糖组分与PPI网络关键调控靶点之间的结合亲和力。
    结果 经筛选,共获得329个与LBPs单糖相关的预测靶点及8 930个ONR相关靶点,二者取交集后得到272个共同靶点。PPI网络分析鉴定出热休克蛋白90α家族A类成员1(HSP90AA1)、热休克蛋白90α家族B类成员1(HSP90AB1)、丝裂原活化蛋白激酶3(MAPK3)、缺氧诱导因子1α亚基(HIF1A)、核因子κB亚基1(NFKB1)及雷帕霉素靶蛋白(MTOR)为按连接度排序的前六位核心靶点。“药物-疾病靶点”网络拓扑学分析显示,木糖、α-L-阿拉伯糖、β-D-氨基葡萄糖、半乳糖及α-D-甘露糖为连接度排序的前五位主要单糖活性成分。GO富集分析表明,重叠靶点主要参与细胞外信号调节激酶1/2(ERK1/2)级联反应的正向调控、MAPK活性的正向调控、细胞缺氧应答、炎症反应的负向调控及胞质钙离子释放等生物学过程。KEGG通路分析显示,上述靶点在HIF-1、神经营养因子、MAPK、磷脂酰肌醇3-激酶–蛋白激酶B(PI3K-Akt)、钙信号、环磷酸腺苷(cAMP)、大鼠肉瘤病毒(Ras)、鞘脂及松弛素等信号通路中显著富集。单细胞转录组分析揭示六个核心靶点在视网膜神经节细胞(RGC)亚群中呈现差异化表达模式:Hsp90aa1Hsp90ab1呈广泛表达,而Mapk3Hif1a则在特定细胞亚群中呈相对富集性表达。五个核心单糖与六个核心靶点之间的分子对接结果显示,结合能介于− 4.3至− 6.9 kcal/mol之间;其中β-D-氨基葡萄糖对多个核心靶点(尤其是MAPK3、NFKB1、HSP90AA1及HSP90AB1)表现出相对较优的结合能,而木糖和α-L-阿拉伯糖虽具有较高的网络连接度,但其预测结合能相对较弱。
    结论 LBPs单糖组分可能通过HSP90AA1、HSP90AB1、MAPK3、HIF1A、NFKB1及MTOR等多个候选靶点参与ONR,并可能涉及HIF-1、神经营养因子、MAPK及PI3K-Akt等信号通路。本研究为进一步实验验证LBPs参与ONR的潜在机制提供了依据。

     

    Abstract:
    Objective To identify the potential molecular mechanisms mediating the role of Lycium barbarum polysaccharides (LBPs) in optic nerve regeneration (ONR) through an integrated approach that combines network pharmacology, single-cell RNA sequencing, and molecular docking.
    Methods The monosaccharide composition of LBPs was systematically characterized, and potential target genes of each LBPs component were predicted using the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP), SwissTargetPrediction, and SuperPred databases. Disease-related targets associated with ONR were retrieved from the Online Mendelian Inheritance in Man (OMIM) and GeneCards databases. A protein-protein interaction (PPI) network of the overlapping targets was established via the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database, and a “drug-disease-target” regulatory network was constructed using Cytoscape software. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were conducted using the Metascape platform to elucidate the potential signaling pathways through which LBPs mediate ONR. Seurat software was used to analyze mouse retinal single-cell RNA sequencing data (GSE137398) retrieved from the Gene Expression Omnibus (GEO) database to evaluate the expression distribution and cellular heterogeneity of the core PPI network targets across different retinal cell clusters. Molecular docking analysis was performed to verify the binding affinity between the core monosaccharide components of LBPs and the key regulatory targets identified from the PPI network.
    Results A total of 329 predicted targets associated with LBPs monosaccharide components and 8 930 ONR-related targets were identified, yielding 272 overlapping targets. PPI network analysis identified heat shock protein 90 α family class A member 1 (HSP90AA1), heat shock protein 90 α family class B member 1 (HSP90AB1), mitogen-activated protein kinase 3 (MAPK3), hypoxia-inducible factor 1 subunit alpha (HIF1A), nuclear factor kappa B subunit 1 (NFKB1), and mechanistic target of rapamycin kinase (MTOR) as the top six core targets ranked by degree value. Drug-disease-target network topology analysis indicated that xylose, α-L-arabinose, β-D-glucosamine, galactose, and α-D-mannose were the top five principal monosaccharide components with the highest connectivity. GO enrichment analysis showed that the overlapping targets were mainly involved in positive regulation of the extracellular signal-regulated kinase 1/2 (ERK1/2) cascade, positive regulation of MAPK activity, cellular response to hypoxia, negative regulation of inflammatory response, and cytosolic calcium ion release. KEGG analysis demonstrated significant enrichment in the HIF-1, neurotrophin, MAPK, phosphoinositide 3-kinase-protein kinase B (PI3K-Akt), calcium, cyclic adenosine monophosphate (cAMP), rat sarcoma virus (Ras), sphingolipid, and relaxin signaling pathways. Single-cell transcriptomic analysis revealed distinct expression patterns of the six core targets across retinal ganglion cell (RGC) subpopulations, with Hsp90aa1 and Hsp90ab1 broadly expressed, whereas Mapk3 and Hif1a exhibited relatively enriched expression in specific clusters. Molecular docking between the five core monosaccharide components and the six core targets showed binding energies ranging from − 4.3 to − 6.9 kcal/mol. β-D-glucosamine demonstrated comparatively favorable binding affinities toward several core targets, particularly MAPK3, NFKB1, HSP90AA1, and HSP90AB1, whereas xylose and α-L-arabinose exhibited higher network connectivity but relatively weaker predicted binding affinities.
    Conclusion The monosaccharide components of LBPs may participate in ONR through multiple candidate targets, particularly HSP90AA1, HSP90AB1, MAPK3, HIF1A, NFKB1, and MTOR, and may involve the HIF-1, neurotrophin, MAPK, and PI3K-Akt signaling pathways. These findings provide a basis for further experimental validation of the potential mechanisms of LBPs in ONR.

     

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