一种新型蓝细菌血清素N-乙酰转移酶基因CySNAT3的克隆及其与转录组药物重定位在儿童阻塞性睡眠呼吸障碍中的整合

文献信息

中文摘要

背景： 褪黑素在儿童阻塞性睡眠呼吸障碍（oSDB）中具有潜在治疗价值。然而，基于植物的褪黑素提取面临生长周期长、产量低和纯化程序复杂等局限。蓝细菌作为光合微生物，具有生长迅速、培养成本低和遗传操作工具成熟等显著优势，是生产高价值天然产物的理想底盘细胞。同时，扁桃体病理与oSDB严重程度相关的分子机制仍知之甚少，亟需转化治疗靶点。
方法： 克隆了一种新型蓝细菌血清素N-乙酰转移酶基因（CySNAT3），在大肠杆菌中表达，并通过Ni-NTA亲和层析纯化。采用HPLC-荧光法评估其酶活性。另外，对扁桃体RNA-seq数据（GSE274855）进行差异表达分析、WGCNA和药物重定位，随后通过分子对接验证药物-靶点相互作用。
结果： CySNAT3催化血清素转化为N-乙酰血清素，并将5-MT转化为褪黑素，为微生物褪黑素生产提供了酶学工具。鉴定出四种高置信度候选药物（磺胺甲噁唑、西咪替丁、己烯雌酚、氯贝特），分子对接证实其与靶蛋白（CYP2C19、SLC47A1、WNT7A、SCD）具有良好的结合亲和力。
结论： 西咪替丁和己烯雌酚已在实验上与褪黑素通路相关联，提示这四种药物可能通过调节褪黑素信号发挥作用。本研究通过整合新型蓝细菌SNAT酶工具与转录组衍生的候选药物，为儿童oSDB治疗提供了新的分子基础。

英文摘要

BACKGROUND: Melatonin has potential therapeutic value in pediatric obstructive sleep-disordered breathing (oSDB). However, plant-based melatonin extraction faces limitations including long growth cycles, low yield, and complex purification procedures. Cyanobacteria, as photosynthetic microorganisms, offer distinct advantages such as rapid growth, low cultivation cost, and well-established genetic manipulation tools, making them ideal chassis cells for producing high-value natural products. Meanwhile, the molecular mechanisms linking tonsillar pathology to oSDB severity remain poorly understood, and translational therapeutic targets are urgently needed.
METHODS: A novel cyanobacterial serotonin N-acetyltransferase gene (CySNAT3) was cloned, expressed in E. coli, and purified by Ni-NTA affinity chromatography. Its enzymatic activity was assessed by HPLC-fluorescence. Separately, differential expression analysis, WGCNA, and drug repurposing were performed on tonsillar RNA-seq data (GSE274855), followed by molecular docking to validate drug-target interactions.
RESULTS: CySNAT3 catalyzed the conversion of serotonin to N-acetylserotonin and 5-MT to melatonin, providing an enzymatic tool for microbial melatonin production. Four high-confidence candidate drugs (sulfamethoxazole, cimetidine, diethylstilbestrol, clofibrate) were identified, with molecular docking confirming favorable binding affinities to their target proteins (CYP2C19, SLC47A1, WNT7A, SCD).
CONCLUSION: Cimetidine and diethylstilbestrol have been experimentally linked to the melatonin pathway, suggesting that these four drugs may act through modulation of melatonin signaling. This study provides a new molecular foundation for pediatric oSDB treatment by integrating a novel cyanobacterial SNAT enzyme tool with transcriptome-derived drug candidates.