Feng Wenjing, Ju Mengwei, Wang Tao, Cui Shanshan, Yang Kexin, Guo Zhiting, Liu Miao, Tao Jiaxuan, Yu Huiyan, Xiao Rong
School of Public Health, Capital Medical University, No.10 Xitoutiao, You An Men Wai, Beijing, China.
Alzheimers Res Ther. 2025 May 13;17(1):102. doi: 10.1186/s13195-025-01743-5.
Oxysterols, gut metabolites, and N6-methyladenosine (m6A) are extensively implicated in the pathogenesis of cognitive dysfunction, while their alterations in different stages of mild cognitive impairment (MCI) have not been elucidated. Therefore, this study was conducted to explore the associations of oxysterols, gut metabolites, and m6A methylation profiles in early MCI (EMCI) and late MCI (LMCI) individuals.
Liquid chromatography-mass spectrometry, untargeted metabolomic analysis, and m6A mRNA Epitranscriptomic Microarray were used to detect the characteristics of serum oxysterols (n = 35/group), fecal gut metabolites (n = 30/group), and m6A in whole blood (n = 4/group) respectively. The concentration of serum β-amyloid (Aβ) was detected with ELISA (n = 25/group). The gene expression of amyloid precursor protein (APP) and its key enzyme β-secretase (BACE1) in whole blood were measured by quantitative real-time PCR (n = 25/group).
EMCIs and LMCIs, especially LMCIs, exhibited poorer performance in almost all global and multidimensional cognitive tests. Serum 27-hydroxycholesterol (27-OHC) and 24S-hydroxycholesterol (24S-OHC) were elevated in EMCI and LMCI groups. Changes in gut metabolites occurred mainly in the EMCI group, in which several gut metabolites, including Procyanidin dimer B7 and Phorbol myristate, were significantly decreased. The m6A methylation landscape of EMCIs and LMCIs obviously differed from Controls. Hypomethylated mRNAs accounted for the majority and were mainly accompanied by downregulated mRNAs, which was consistent with the downregulated expression of the m6A writer methyltransferase-like 4 (METTL4). 27-OHC and 24S-OHC combined with various gut metabolites significantly distinguished between MCI subgroups from healthy controls (EMCI/Control: AUC = 0.877; LMCI/Control: AUC = 0.952). Heatmap revealed the correlation between Phorbol myristate and differentially m6A-methylated mRNAs. Differentially expressed gut metabolites and methylated mRNAs were commonly enriched in 34 KEGG metabolic pathways, including cholesterol metabolism and neurodegenerative disease-related pathways.
Our study explored the altered oxysterols, gut metabolites, and m6A methylation and their associations in different stages of MCI. The potential function of aberrant gut metabolites in oxysterols and m6A methylation driving MCI progression warrants further mechanistic investigation.
氧化甾醇、肠道代谢物和N6-甲基腺苷（m6A）广泛参与认知功能障碍的发病机制，而它们在轻度认知障碍（MCI）不同阶段的变化尚未阐明。因此，本研究旨在探讨早期MCI（EMCI）和晚期MCI（LMCI）个体中氧化甾醇、肠道代谢物和m6A甲基化谱之间的关联。
分别采用液相色谱-质谱联用、非靶向代谢组学分析和m6A mRNA表观转录组微阵列检测血清氧化甾醇（每组n = 35）、粪便肠道代谢物（每组n = 30）和全血中m6A（每组n = 4）的特征。用ELISA法检测血清β-淀粉样蛋白（Aβ）浓度（每组n = 25）。通过定量实时PCR检测全血中淀粉样前体蛋白（APP）及其关键酶β-分泌酶（BACE1）的基因表达（每组n = 25）。
EMCI和LMCI个体，尤其是LMCI个体，在几乎所有整体和多维认知测试中表现较差。EMCI组和LMCI组血清27-羟基胆固醇（27-OHC）和24S-羟基胆固醇（24S-OHC）升高。肠道代谢物变化主要发生在EMCI组，其中几种肠道代谢物，包括原花青素二聚体B7和肉豆蔻酸佛波醇，显著减少。EMCI和LMCI的m6A甲基化图谱明显不同于对照组。低甲基化mRNA占大多数，且主要伴随着mRNA表达下调，这与m6A写入器甲基转移酶样4（METTL4）的表达下调一致。27-OHC和24S-OHC与多种肠道代谢物相结合，可显著区分MCI亚组与健康对照组（EMCI/对照组：AUC = 0.877；LMCI/对照组：AUC = 0.952）。热图显示肉豆蔻酸佛波醇与差异m6A甲基化mRNA之间的相关性。差异表达的肠道代谢物和甲基化mRNA通常富集于34条KEGG代谢途径中，包括胆固醇代谢和神经退行性疾病相关途径。
我们的研究探讨了MCI不同阶段氧化甾醇、肠道代谢物和m6A甲基化的变化及其关联。异常肠道代谢物在氧化甾醇和m6A甲基化驱动MCI进展中的潜在作用值得进一步进行机制研究。
