title: Induction of circadian rhythm in cultured human mesenchymal stem cells by serum shock and cAMP analogs in vitro.
abstract: Circadian clocks have been shown to operate developmentally in mouse and human hematopoietic stem and progenitor cells in vivo, but little is known about their possible oscillations in vitro. Here, we show that repeated circadian oscillations could be induced in both cultured bone marrow-derived mesenchymal- and adipose-derived stem cells (MSCs and ASCs, respectively) by serum shock. In particular, the novel finding of rhythmic clock gene expression induced by cAMP analogs showed similarities as well as differences to serum-induced oscillations. Rhythmic PER1 expression was found in serum-shocked MSCs, suggesting the phosphorylation status of PER1 is important for its activity in circadian rhythms. Furthermore, immunofluoresent staining showed that the localization of PER1 was dependent on the level of PER1 expression. These inducible self-sustained circadian clocks in primary cultures of human MSCs in vitro with rhythmic changes in expression levels, phosphorylation, and localization of clock protein, PER1, may be of importance for maintaining the induced oscillations in stem cells. Therefore, the established cell models described here appear to be valuable for studying the molecular mechanism driving and coordinating the circadian network between stem and stromal cells.
authors.affiliation: The Gade Institute, Section of Pathology; and Department of Pathology, Haukeland University Hospital, Bergen, Norway. tihu@nifes.no
authors.forename: Tien-Sheng
authors.initials: TS
authors.lastname: Huang
authors.forename: Gunnveig
authors.initials: G
authors.lastname: Grodeland
authors.forename: Linda
authors.initials: L
authors.lastname: Sleire
authors.forename: Meng Yu
authors.initials: MY
authors.lastname: Wang
authors.forename: Gunnar
authors.initials: G
authors.lastname: Kvalheim
authors.forename: Ole Didrik
authors.initials: OD
authors.lastname: Laerum
mesh_terms: D000273:Adipose Tissue / Q000166:cytology; D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000502:physiology; D056926:CLOCK Proteins; D002478:Cells, Cultured; D002940:Circadian Rhythm / Q000502:physiology*; D000242:Cyclic AMP / Q000031:analogs & derivatives*; D005786:Gene Expression Regulation; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000502:physiology*; D051379:Mice; D056950:Period Circadian Proteins; D044967:Serum / Q000378:metabolism*; D013312:Stress, Physiological; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; C539022:PER1 protein, human; C539023:Per1 protein, mouse; D056950:Period Circadian Proteins; D015534:Trans-Activators; D000242:Cyclic AMP; D056926:CLOCK Proteins; C538943:CLOCK protein, human; C538944:Clock protein, mouse