Gu Yuzhou, Chen Lu, Chen Shuying, Wu Yuhao, Hao Shengjie, Sheng Feiyin, Yuan Jiali, Qin Zhenwei, Wu Di, Han Yu, Yao Zengying, Chen Zhijian, Wormstone I Michael, Yu Yibo, Qian Junbin, Fu Qiuli, Yao Ke
Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang Provincial Key Lab of Ophthalmology, Zhejiang Provincial Clinical Research Center for Eye Diseases, Zhejiang Provincial Engineering Institute on Eye Disease, Medical College of Zhejiang University, Hangzhou, 310009, Zhejiang Province, China.
Human Eye Research Lab, Research Centre for Life Science and Healthcare, Nottingham Ningbo China Beacons of Excellence Research and Innovation Institute (CBI), University of Nottingham Ningbo China, Ningbo, Zhejiang Province, China.
Stem Cell Res Ther. 2025 Jul 1;16(1):333. doi: 10.1186/s13287-025-04436-w.
The existence of stem/progenitor cells in the lens epithelium has been demonstrated, but their identification remains challenging. Accurate identification requires advanced technologies and a comprehensive understanding of lens epithelial cell (LEC) subtypes, presenting a significant challenge in age-related cataract research.
Eight pairs of human donor lens epithelium samples were collected for single-cell RNA sequencing (scRNA-seq). This included four non-aged (< 65 years) and four aged (> 65 years) individuals. Subsequent analyses involved cell (sub)type characterization, trajectory inference, and cell-cell communication. Experimental validation was conducted through transcriptome sequencing and immunofluorescence on human lenses, lens organoids, rabbit regenerated lenses, mouse lenses, and cell lines.
Six groups were identified via UMAP mapping of scRNA-seq data: four LECs, one lens fiber cells (LFCs), and one immune cells. One of the four LEC clusters exhibited a distinct gene expression profile and was identified as transient amplifying cells (TACs). TACs specifically express TOP2A and are localized at the lens equator. CytoTRACE analysis to the LEC and LFC data sets provided a differentiation trajectory. The TAC group was determined as stage 2 in the trajectory and LFCs last. The 3 sub groups were labelled early, mid and late LECs and corresponded to stage 1, 3 and 4 in the path. While cell population demographics remained stable with age, transcriptomic changes in LECs were observed, including weaker intercellular crosstalk and adhesion, and fewer TACs in S phase. Lens progenitor-like cells (LPLCs) were identified as a sub-population in early LECs and express ID1. In addition, pleiotrophin (PTN) signaling was prevalent at all differentiation stages, with a notable weakening of PTN signaling in aged LPLCs.
This study identified four subclasses of LECs within the human lens epithelium that follow a progressive staged development pathway from progenitor cells to mature LECs. TOP2A can serve as a biomarker for TAC in the lens, and LPLCs sustain their dedifferentiated state by expressing ID1. The aging process does not appear to alter cell population demographics, but significant alteration in gene expression profile is observed. Moreover, PTN signaling emerges as a crucial factor in lens homeostasis and represents a potential target for cataract drug development.
晶状体上皮中存在干细胞/祖细胞已得到证实，但其鉴定仍具有挑战性。准确鉴定需要先进技术以及对晶状体上皮细胞（LEC）亚型的全面了解，这在年龄相关性白内障研究中是一项重大挑战。
收集了八对人类供体晶状体上皮样本用于单细胞RNA测序（scRNA-seq）。其中包括四名非老年（<65岁）和四名老年（>65岁）个体。后续分析包括细胞（亚）类型表征、轨迹推断和细胞间通讯。通过对人类晶状体、晶状体类器官、兔再生晶状体、小鼠晶状体和细胞系进行转录组测序和免疫荧光进行实验验证。
通过scRNA-seq数据的UMAP映射鉴定出六个组：四个LEC组、一个晶状体纤维细胞（LFC）组和一个免疫细胞组。四个LEC簇中的一个表现出独特的基因表达谱，并被鉴定为瞬时扩增细胞（TAC）。TAC特异性表达TOP2A并定位于晶状体赤道。对LEC和LFC数据集进行的CytoTRACE分析提供了一条分化轨迹。TAC组被确定为轨迹中的第2阶段，LFC为最后阶段。这三个亚组分别标记为早期、中期和晚期LEC，对应于轨迹中的第1、3和4阶段。虽然细胞群体特征随年龄保持稳定，但观察到LEC的转录组变化，包括细胞间串扰和粘附减弱，以及S期的TAC减少。晶状体祖细胞样细胞（LPLC）被鉴定为早期LEC中的一个亚群并表达ID1。此外，多效生长因子（PTN）信号在所有分化阶段都很普遍，在老年LPLC中PTN信号明显减弱。
本研究在人类晶状体上皮中鉴定出四个LEC亚类，它们遵循从祖细胞到成熟LEC的渐进性分期发育途径。TOP2A可作为晶状体中TAC的生物标志物，LPLC通过表达ID1维持其去分化状态。衰老过程似乎并未改变细胞群体特征，但观察到基因表达谱有显著改变。此外，PTN信号成为晶状体稳态的关键因素，代表了白内障药物开发的潜在靶点。
