scRNA-Seq: First Atlas and Cellular Landscape of Lacrimal Sac: Implications in Primary Acquired Nasolacrimal Duct Obstruction Pathogenesis.. scRNA-Seq: First Atlas and Cellular Landscape of Lacrimal Sac: Implications in Primary Acquired Nasolacrimal Duct Obstruction Pathogenesis.

Purpose: The aim of the study is to describe the transcriptional changes of individual cellular components in the lacrimal sac in patients with primary acquired nasolacrimal duct obstruction (PANDO) and attempt to construct the first lacrimal sac cellular atlas to elucidate the potential mechanisms that may drive the disease pathogenesis. Methods: Lacrimal sac samples were obtained intraoperatively during the endoscopic dacryocystorhinostomy (EnDCR) procedure from five patients. Single-cell RNA sequencing was performed to analyze each individual cell population including epithelial and immune cells during the early-inflammatory and late-inflammatory phases of the disease. Results: Eleven cell types were identified among 25,791 cells. T cells and B cells were the cell populations with the greatest variation in cell numbers between the two phases and were, involved in immune response and epithelium migration-related pathways. The present study showed that epithelial cells highly expressed the genes of senescence-associated secretory phenotype (SASP) and were involved in influencing the inflammation, neutrophil chemotaxis, and migration during the late-inflammatory stage. Enhanced activity of CXCLs-CXCRs between the epithelial cells and neutrophils was noted by the cell-cell communication analysis and is suspected to play a role in inflammation by recruiting more neutrophils. Conclusions: The study presents a comprehensive single-cell landscape of the lacrimal sac cells in different phases of PANDO. The contribution of T, B cells and epithelial cells to the inflammatory response, and construction of the intercellular signaling networks between the cells within the lacrimal sac has further enhanced the present understanding of the PANDO pathogenesis. Overall design: using BD Rhapsody system in March 2023

### 研究目的：本研究旨在描述原发性获得性鼻泪管阻塞（primary acquired nasolacrimal duct obstruction, PANDO）患者泪囊的单个细胞组分转录组变化，并尝试构建首个泪囊细胞图谱，以阐明可能驱动该疾病发病机制的潜在分子机制。
### 研究方法：本研究从5例接受内镜下泪囊鼻腔吻合术（endoscopic dacryocystorhinostomy, EnDCR）的患者术中获取泪囊样本。采用单细胞RNA测序（single-cell RNA sequencing）分析疾病早期炎症期与晚期炎症期的各类细胞群，包括上皮细胞与免疫细胞。
### 研究结果：本研究在25791个细胞中鉴定出11种细胞类型。T细胞与B细胞是两个炎症阶段细胞数量差异最显著的细胞群，且参与免疫应答与上皮迁移相关通路。本研究发现，上皮细胞高表达衰老相关分泌表型（senescence-associated secretory phenotype, SASP）相关基因，并在晚期炎症阶段参与调控炎症反应、中性粒细胞趋化与迁移过程。细胞间通讯分析显示，上皮细胞与中性粒细胞之间的CXCLs-CXCRs通路活性增强，推测该通路可通过招募更多中性粒细胞参与炎症反应。
### 研究结论：本研究揭示了PANDO不同炎症阶段泪囊细胞的全面单细胞转录组图谱。明确了T细胞、B细胞及上皮细胞在炎症应答中的作用，并构建了泪囊内细胞间的信号网络，进一步加深了对PANDO发病机制的理解。
### 整体实验设计：2023年3月采用BD Rhapsody系统完成。