Abstract
Aging results in deterioration of body functions and, ultimately, death. miRNAs contribute to the regulation of aging. The aim of this study was to explore the contribution of miRNAs to aging and senescence-related changes in gene expression. The expression changes of miRNAs in the blood of people and animal samples collected from different age subjects were examined using Affymetrix miRNA 4.0 microarray and qRT-PCR. MTT assay and flow cytometry were used to examine the effect of miR-23a on cell functions in WI-38 cells. The expression levels of 48 miRNAs, including miR-23a, miR-21, and miR-100, in the blood samples were higher in the middle-aged group than in the young or elderly group. Animal studies further suggested that the expression of miR-23a increased with age. In addition, upregulation of miR-23a dramatically suppressed the cell proliferation and arrested the WI-38 cell cycle in vitro. FOXO3a has been identified as a target gene of miR-23a. MiR-23a downregulated the expression of FOXO3a in WI-38 cells. MiRNAs have different expression levels in different age groups. miR-23a could suppress cell proliferation and arrest the cell cycle in WI-38 cells, which elucidated the mechanism through which miR-23a exerts pivotal role in WI-38 cells by targeting FOXO3a.