title: CLOCK promotes 3T3-L1 cell proliferation via Wnt signaling.
abstract: Circadian genes control most of the physiological functions including cell cycle. Cell proliferation is a critical factor in the differentiation of progenitor cells. However, the role of Clock gene in the regulation of cell cycle via wingless-type (Wnt) pathway and the relationship between Clock and adipogenesis are unclear. We found that the circadian locomotor output cycles kaput (Clock) regulated the proliferation and the adipogenesis of 3T3-L1 preadipocytes. We found that Clock attenuation inhibited the viability of 3T3-L1 preadipocytes in the cell counting kit 8. The expression of c-Myc and Cyclin D1 decreased dramatically in 3T3-L1 when Clock was silenced with short interfering RNA and was also decreased in fat tissue and adipose tissue-derived stem cells of Clock(Δ19) mice. Clock directly controls the expression of the components of Wnt signal transduction pathway, which was verified by serum shock, chromatin immunoprecipitation, Western blot, and quantitative real-time polymerase chain reaction (qRT-PCR). Furthermore, IWR-1, a Wnt signal pathway inhibitor, inhibited the cell cycle promotion by CLOCK, which was detected by cell viability assay, flow cytometry, and qRT-PCR. Therefore, CLOCK transcription control of Wnt signaling promotes cell cycle progression in 3T3-L1 preadipocytes. Clock inhibited the adipogenesis on day 2 in 3T3-L1 cells via Oil Red O staining and qRT-PCR detection and probably related to cellular differentiation. These data provide evidence that the circadian gene Clock regulates the proliferation of preadipocytes and affects adipogenesis. © 2016 IUBMB Life, 68(7):557-568, 2016.
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai, China.
authors.forename: Zhu
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Department of Orthopedics, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Bingxuan
authors.initials: B
authors.lastname: Hua
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai, China.
authors.forename: Lirong
authors.initials: L
authors.lastname: Xu
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai, China.
authors.forename: Gongsheng
authors.initials: G
authors.lastname: Yuan
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai, China.
authors.forename: Ermin
authors.initials: E
authors.lastname: Li
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai, China.
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Sun
authors.affiliation: Department of Orthopedics, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Zuoqin
authors.initials: Z
authors.lastname: Yan
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Lu
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai, China.
authors.forename: Ruizhe
authors.initials: R
authors.lastname: Qian
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000378:metabolism; D050156:Adipogenesis / Q000235:genetics*; D000818:Animals; D056926:CLOCK Proteins / Q000235:genetics*; D002454:Cell Differentiation / Q000235:genetics; D049109:Cell Proliferation / Q000235:genetics*; D002470:Cell Survival / Q000235:genetics; D019938:Cyclin D1 / Q000235:genetics; D005786:Gene Expression Regulation; D051379:Mice; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics*; D013234:Stem Cells / Q000378:metabolism; D060449:Wnt Signaling Pathway / Q000235:genetics
chemical_list: C530105:Ccnd1 protein, mouse; D047495:PPAR gamma; D016271:Proto-Oncogene Proteins c-myc; D019938:Cyclin D1; D056926:CLOCK Proteins; C538944:Clock protein, mouse
keywords: 3T3-L1 preadipocyte; Wnt signal pathway; circadian locomotor output cycles kaput; proliferation