title: MicroRNA-181a-5p enhances cell proliferation in medullary thymic epithelial cells via regulating TGF-β signaling.
abstract: The expression profiles of miRNAs in thymus tissues from mice of different age have been demonstrated in our previous study. After an integrated analysis of the miRNA expression profiles, we demonstrated that the expression of miR-181a-5p was significantly decreased in thymic epithelial cells (TECs) from 10- to 19-month-old mice when compared with that in TECs from 1-month-old mice by quantitative reverse transcriptase polymerase chain reaction. We hypothesized that miR-181a-5p in TECs might be associated with the age-related thymus involution through regulating some genes or signaling pathway. To test this hypothesis, the mouse medullary thymic epithelial cells (MTEC1) were used. Transfection with miR-181a-5p mimic promoted the proliferation of MTEC1 cells, but did not affect apoptosis. The effect was reversed when the expression of miR-181a-5p was suppressed in MTEC1 cells. Furthermore, the transforming growth factor beta receptor I (Tgfbr1) was confirmed as a direct target of miR-181a-5p by luciferase assay. Moreover, it was found that overexpression of miR-181a-5p down-regulated the phosphorylation of Smad3 and blocked the activation of the transforming growth factor beta signaling. Nevertheless, an inversely correlation was observed between the expression of Tgfbr1 and miR-181a-5p in TECs derived from mice of different age. Collectively, we provide evidence that miR-181a-5p may be an important endogenous regulator in the proliferation of TECs, and the expression levels of miR-181a-5p in TECs may be associated with the age-related thymus involution.
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Dongguang
authors.initials: D
authors.lastname: Guo
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Yaqiong
authors.initials: Y
authors.lastname: Ye
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Junjie
authors.initials: J
authors.lastname: Qi
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Lihua
authors.initials: L
authors.lastname: Zhang
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Lifeng
authors.initials: L
authors.lastname: Xu
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Xiaotong
authors.initials: X
authors.lastname: Tan
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Yu
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Qihong
authors.initials: Q
authors.lastname: Liu
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Jilong
authors.initials: J
authors.lastname: Liu
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China yuguli99@163.com 462700840@qq.com.
authors.forename: Yongjiang
authors.initials: Y
authors.lastname: Ma
authors.affiliation: College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China yuguli99@163.com 462700840@qq.com.
authors.forename: Yugu
authors.initials: Y
authors.lastname: Li
mesh_terms: D000375:Aging / Q000235:genetics / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000502:physiology; D002460:Cell Line; D049109:Cell Proliferation / Q000235:genetics / Q000502:physiology; D002470:Cell Survival / Q000235:genetics / Q000502:physiology; D015536:Down-Regulation; D004847:Epithelial Cells / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D035683:MicroRNAs / Q000235:genetics*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D051900:Smad3 Protein / Q000235:genetics / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology* / Q000378:metabolism*; D059467:Transcriptome; D016212:Transforming Growth Factor beta / Q000378:metabolism*
chemical_list: D035683:MicroRNAs; D018125:Receptors, Transforming Growth Factor beta; D051900:Smad3 Protein; C497791:Smad3 protein, mouse; D016212:Transforming Growth Factor beta; C529100:mirn181 microRNA, mouse; D017346:Protein Serine-Threonine Kinases; D000077293:Receptor, Transforming Growth Factor-beta Type I; C000625842:Tgfbr1 protein, mouse
keywords: TGF-β signaling; Tgfbr1; cell proliferation; miR-181a-5p; mouse thymic epithelial cell