基于单细胞转录组的视网膜母细胞瘤进展特征分析

Analysis of progress characteristics of retinoblastoma based on single cell transcriptome sequencing

摘要:

视网膜母细胞瘤（retinoblastoma，RB）是婴幼儿最常见的眼内恶性肿瘤。在RB进展过程中的关键致病因素目前尚不十分清楚。因此，识别与RB进展密切相关的基因能为病情诊断及基因治疗提供重要信息。然而，肿瘤组织具有很强的细胞异质性，不同病理状态下的细胞，其功能及基因表达都可能呈现显著的差异。本研究从公共基因表达数据库（gene expression omnibus，GEO）下载了1例4个月肿瘤患者和1例2年患者的肿瘤及癌旁组织的单细胞转录组测序数据，从单细胞水平解析不同患病时长的RB肿瘤转录图谱，鉴定与RB进展有潜在关联的细胞亚群及基因集。结果显示，肿瘤组织与癌旁组织在单细胞转录图谱上具有整体的一致性，但视锥前体G1期细胞群、G2期细胞群以及小胶质细胞群在肿瘤与癌旁组织中的分布比例存在明显差异。进一步分析了这3种细胞群在RB肿瘤进展过程中的作用。研究发现，在RB肿瘤的早期阶段，视锥前体细胞在G1期异常增殖，随着RB肿瘤的进展，视锥前体G2期细胞比例显著增加。同时，RB进展过程的小胶质细胞群差异分析结果显示，主要参与免疫应答的关键基因包括RPL23、B2M、HLA家族基因。本研究可为RB发病机制及进展研究提供更多新视角和数据资源。

Abstract:

Retinoblastoma (RB) is the most common intraocular malignant tumor in infants and young children. The key causative factors in the progression of RB remain unclear. Therefore, identifying genes closely associated with RB progression may provide important clues for disease diagnosis and gene therapy. However, tumor tissues have strong cellular heterogeneity. There may be significant differences in cell function and gene expression among cells in different pathological states. In this study, we downloaded single-cell transcriptome sequencing data of RB tumors and adjacent tissues from the GEO public database. Subsequently, we analyzed RB tumor transcriptional profiles with different disease duration at the single-cell level and identified cell groups and gene sets potentially associated with RB progression. The results showed that the tumor tissue and the adjacent tissues had overall consistency in the single-cell transcriptional map, but there were obvious differences in the distribution proportions of G1 phase cells, G2 phase cells, and microglia cells of cone precursors in RB tumor and the adjacent tissues. Furthermore, the role of three cell populations in the progression of RB tumors was emphatically analyzed. We found that in the early stage of RB tumors, cone precursor cells proliferated abnormally in G1 phase. With the progression of RB tumors, the proportion of cone precursor cells in G2 phase increased significantly. Meanwhile, the results of differential analysis of microglial populations during RB progression showed that the key genes mainly involved in immune response include RPL23, B2M, and HLA superfamily genes. This study provides new perspectives and data resources for the research of RB pathogenesis and progress.