Adamantinomatous craniopharyngioma cyst fluid can trigger inflammatory activation of microglia to damage the hypothalamic neurons by inducing the production of β-amyloid

Introduction: The mechanism by which adamantinomatous craniopharyngioma (ACP) damages the hypothalamus is still unclear. Cyst fuid rich in lipids and infammatory factors is a characteristic pathological manifestation of ACP and may play a very important role in hypothalamic injury caused by tumors. Objective: The objective of this study was to construct a reliable animal model of ACP cyst fuid-induced hypotha lamic injury and explore the specifc mechanism of hypothalamic injury caused by cyst fuid. Methods: An animal model was established by injecting human ACP cyst fuid into the bilateral hypothalamus of mice. ScRNA-seq was performed on the mice hypothalamus and on an ACP sample to obtain a complete gene expression profle for analysis. Data verifcation was performed through pathological means. Results: ACP cystic fuid caused growth retardation and an increased obesity index in mice, afected the expres sion of the Npy, Fgfr2, Rnpc3, Sst, and Pcsk1n genes that regulate growth and energy metabolism in hypothalamic neurons, and enhanced the cellular interaction of Agrp–Mc3r. ACP cystic fuid signifcantly caused infammatory activation of hypothalamic microglia. The cellular interaction of CD74–APP is signifcantly strengthened between infammatory activated microglia and hypothalamic neurons. Beta-amyloid, a marker of neurodegenerative diseases, was deposited in the ACP tumor tissues and in the hypothalamus of mice injected with ACP cyst fuid. Conclusion: In this study, a novel animal model of ACP cystic fuid-hypothalamic injury was established. For the frst time, it was found that ACP cystic fuid can trigger infammatory activation of microglia to damage the hypothalamus, which may be related to the upregulation of the CD74–APP interaction and deposition of β-amyloid, implying that there may be a similar mechanism between ACP cystic fuid damage to the hypothalamus and neurodegenerative diseases. 1 case of mouse hypothalamus injected with human ACP cystic fluid,1 case of mouse hypothalamus injected with PBS,1 case of human ACP tumor tissue were used for scRNA-seq

引言：造釉细胞瘤型颅咽管瘤（adamantinomatous craniopharyngioma, ACP）损伤下丘脑的具体机制尚未阐明。富含脂质与炎症因子的囊液是ACP的特征性病理表现，其在肿瘤介导的下丘脑损伤中可能扮演关键角色。
研究目的：本研究拟构建稳定可靠的ACP囊液诱导性下丘脑损伤动物模型，并深入探究囊液引发下丘脑损伤的具体分子机制。
研究方法：通过向小鼠双侧下丘脑注射人ACP囊液构建动物模型；对小鼠下丘脑及1例ACP肿瘤样本开展单细胞RNA测序（single-cell RNA sequencing, scRNA-seq），获取完整基因表达谱用于后续分析，并通过病理学方法对测序数据进行验证。
研究结果：ACP囊液可导致小鼠出现生长发育迟缓及肥胖指数升高，影响下丘脑神经元中调控生长与能量代谢的Npy、Fgfr2、Rnpc3、Sst及Pcsk1n基因的表达，并增强Agrp–Mc3r介导的细胞互作水平。此外，ACP囊液可显著诱导下丘脑小胶质细胞发生炎症激活；炎症激活的小胶质细胞与下丘脑神经元之间的CD74–APP细胞互作显著增强。在ACP肿瘤组织及注射ACP囊液的小鼠下丘脑中，均检测到神经退行性疾病标志物β淀粉样蛋白的沉积。
研究结论：本研究成功构建了一种新型ACP囊液诱导性下丘脑损伤动物模型。本研究首次发现，ACP囊液可通过触发小胶质细胞炎症反应损伤下丘脑，该过程可能与CD74–APP互作上调及β淀粉样蛋白沉积相关，提示ACP囊液所致下丘脑损伤与神经退行性疾病之间可能存在相似的发病机制。
本次研究共纳入3份样本用于单细胞RNA测序：1例注射人ACP囊液的小鼠下丘脑组织、1例注射磷酸盐缓冲液（phosphate buffered saline, PBS）的小鼠下丘脑组织、1例人ACP肿瘤组织