Unveiling the Impact of 17β-Estradiol on Thymic Epithelial Cell Proliferation: A miRNA Perspective

Abstract

Abstract Background Estrogen signaling and microRNA (miRNA) expression play a pivotal role in thymus involution by regulating thymic epithelial cell (TECs) functions. However, the role of Estrogen on miRNA expression in TECs has not been fully elucidated. Methods Cell proliferation assays, such as the cell-counting kit-8 (CCK-8), 5-Ethynyl-2'-deoxyuridine (EdU) and flow cytometry assays were conducted. Next-generation sequencing (NGS)-based miRNA profiling was performed and validated using Quantitative polymerase chain reaction (qPCR). Additionally, the mechanism of 17β-Estradiol(E2) regulation of miRNA expression in MTEC1 cells was investigated using anti-estrogen ICI 182, 780 and ERα siRNA. Results A total of 3356 candidate miRNAs across the six miRNA libraries were subjected to analysis, among these, 69 miRNAs displayed notable changes in expression patterns, with 33 miRNAs exhibiting downregulation and 36 miRNAs showing upregulation. Further investigation focused on miR-99a-5p, miR-99b-5p, miR-378a-5p, miR-361-5p, miR-16-5p, and miR-22-3p due to their elevated expression levels. Subsequent examination through Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed a significant association between the dysregulated miRNAs and the functional role of cell proliferation. Furthermore, the regulatory impact of E2 on miRNA expression can be modified by the anti-estrogen ICI 182 780 or inhibited by ERαsiRNA in MTEC1 cells. Conclusions E2 canalter miRNA expression in TECs, and this miRNA expression may be closely associated with post-transcriptional regulation of cell proliferation in an ERα-dependent manner. Our data indicated the good performance of these miRNAs as potential biomarkers in E2-related thymic involution in TECs.