Chen Xiaoniao, Zhang Chuyue, Tian Lei, Wu Lingling, Jie Ying, Wang Ningli, Liu Ran, Wang Liqiang
Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing Tongren Hospital, Capital Medical University, Beijing, China; State Key Laboratory of Kidney Diseases, Chinese PLA General Hospital, Beijing, China; Senior Department of Ophthalmology, Chinese PLA General Hospital, Beijing, China.
State Key Laboratory of Kidney Diseases, Chinese PLA General Hospital, Beijing, China.
Ocul Surf. 2022 Apr;24:51-63. doi: 10.1016/j.jtos.2021.12.013. Epub 2022 Jan 3.
Dry eye disease (DED) is a chronic multifactorial disorder affecting millions of people, yet the pathogenesis mechanisms still remain unclear. Matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) is a novel in situ visualization approach combined high-throughput mass spectrometry and molecular imaging. We aimed to explore the in situ ocular metabolic changes via MALDI-MSI to accelerate the recognition of DED pathogenesis.
Experimental dry eye was established in Wistar rats by subcutaneous injection of scopolamine. The induction of DED was assessed by tear film breakup time, sodium fluorescein, histopathological staining and cell apoptosis. MALDI-MSI was applied to explore in situ ocular metabolomic in DED rats, and histopathological staining from same sections were used for side-by-side comparison with MALDI to annotate different tissue structures in the eye.
Considering the complexity of ocular tissue, we visualized the metabolites in specific ocular regions (central cornea, peripheral cornea, fornix conjunctiva, eyelid conjunctiva and aqueous humor), and identified metabolites related to DED, with information of relative abundance and spatial signatures. In addition, integrative pathway analysis illustrated that, several metabolic pathways such as glycerophospholipid, sphingolipid phenylalanine, and metabolism of glycine, serine and threonine were significantly altered in certain regions in the dry eye tissue. Moreover, we discussed how the metabolic pathways with spatiotemporal signatures might be involved in the DED process.
Our data exploit the advantages of in situ analysis of MALDI-MSI to accurately analyze the region-specific metabolic behaviors in DED, and provide new clues to uncover DED pathogenesis.
干眼症（DED）是一种影响数百万人的慢性多因素疾病，但其发病机制仍不清楚。基质辅助激光解吸电离质谱成像（MALDI-MSI）是一种将高通量质谱和分子成像相结合的新型原位可视化方法。我们旨在通过MALDI-MSI探索眼部原位代谢变化，以加速对DED发病机制的认识。
通过皮下注射东莨菪碱在Wistar大鼠中建立实验性干眼症。通过泪膜破裂时间、荧光素钠、组织病理学染色和细胞凋亡评估DED的诱导情况。应用MALDI-MSI探索DED大鼠的眼部原位代谢组学，并将同一切片的组织病理学染色与MALDI进行并排比较，以注释眼中不同的组织结构。
考虑到眼部组织的复杂性，我们可视化了特定眼部区域（中央角膜、周边角膜、穹窿结膜、睑结膜和房水）中的代谢物，并鉴定了与DED相关的代谢物，同时获得了相对丰度和空间特征信息。此外，综合通路分析表明，在干眼症组织的某些区域，甘油磷脂、鞘脂苯丙氨酸以及甘氨酸、丝氨酸和苏氨酸的代谢等几种代谢通路发生了显著改变。此外，我们还讨论了具有时空特征的代谢通路可能如何参与DED过程。
我们的数据利用了MALDI-MSI原位分析的优势，准确分析了DED中区域特异性的代谢行为，并为揭示DED发病机制提供了新线索。
