Identification of microRNAs that mediate thyroid cell growth induced by TSH.
TSH is a major regulator of thyroid cell growth and endocrine function. It is known that cAMP and phosphatidylinositol 3-kinase (PI3K) are responsible for mediating the action of TSH. Activation of these signals results in the induction of a series of transcription factors and cell cycle regulating proteins, which induce cell proliferation. In addition to such canonical transcriptional regulation, it was recently shown that microRNA (miRNA or miR) constitutes another key mechanism for the regulation of gene expression. However, whether TSH action is mediated by miRNA in the thyroid is unknown. In this study, we have performed miRNA microarray analysis and demonstrated that TSH significantly decreases expression of 47 miRNA in thyroid cells. Among these, we have shown, using their specific agonists, that overexpression of miR-16 and miR-195 suppressed cell cycle progression and DNA synthesis that was induced by TSH. In silico analysis predicted that Mapk8, Ccne1, and Cdc6, the expression of which was up-regulated by TSH, are potential target genes for these miRNA, and overexpression of miR-16 and miR-195 suppressed expression of these target genes. The decrease of miR-16 and miR-195 expression by TSH was reproduced by forskolin and N(6),2'-O-dibutyryladenosine cAMP and reversed by the protein kinase A inhibitor H89 and the PI3K inhibitor LY294002. These results suggest that TSH activates cAMP/protein kinase A and PI3K cascades to decrease miR-16 and miR-195, which induce Mapk8, Ccne1, and Cdc6 to activate cell proliferation.
Laboratory of Molecular Diagnostics, Department of Mycobacteriology, Leprosy Research Center, National Institute of Infectious Diseases, 4-2-1 Aoba-cho, Higashimurayama-shi, Tokyo, Japan.
Takeshi
T
Akama
Mariko
M
Sue
Akira
A
Kawashima
Huhehasi
H
Wu
Kazunari
K
Tanigawa
Sayuri
S
Suzuki
Moyuru
M
Hayashi
Aya
A
Yoshihara
Yuko
Y
Ishido
Norihisa
N
Ishii
Koichi
K
Suzuki
D000818:Animals; D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D049109:Cell Proliferation; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D019927:Cyclin E / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D048055:Mitogen-Activated Protein Kinase 8 / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction; D013961:Thyroid Gland / Q000166:cytology*; D013972:Thyrotropin / Q000502:physiology*
C528180:Cdc6 protein, rat; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D019927:Cyclin E; D035683:MicroRNAs; D012333:RNA, Messenger; D013972:Thyrotropin; D000242:Cyclic AMP; D019869:Phosphatidylinositol 3-Kinases; D017868:Cyclic AMP-Dependent Protein Kinases; D048055:Mitogen-Activated Protein Kinase 8