title: Circadian mechanisms in murine and human bone marrow mesenchymal stem cells following dexamethasone exposure.
abstract: A core group of regulatory factors control circadian rhythms in mammalian cells. While the suprachiasmatic nucleus in the brain serves as the central core circadian oscillator, circadian clocks also exist within peripheral tissues and cells. A growing body of evidence has demonstrated that >20% of expressed mRNAs in bone and adipose tissues oscillate in a circadian manner. The current manuscript reports evidence of the core circadian transcriptional apparatus within primary cultures of murine and human bone marrow-derived mesenchymal stem cells (BMSCs). Exposure of confluent, quiescent BMSCs to dexamethasone synchronized the oscillating expression of the mRNAs encoding the albumin D binding protein (dbp), brain-muscle arnt-like 1 (bmal1), period 3 (per3), rev-erb alpha (Rev A), and rev-erb beta (Rev B). The genes displayed a mean oscillatory period of 22.2 to 24.3 h. The acrophase or peak expression of mRNAs encoding "positive" (bmal1) and "negative" (per3) components of the circadian regulatory apparatus were out of phase with each other by approximately 8-12 h, consistent with in vivo observations. In vivo, phosphyrylation by glycogen synthase kinase 3beta (GSK3beta) is known to regulate the turnover of per3 and components of the core circadian regulatory apparatus. In vitro addition of lithium chloride, a GSK3beta inhibitor, significantly shifted the acrophase of all genes by 4.2-4.7 h oscillation in BMSCs; however, only the male murine BMSCs displayed a significant increase in the length of the period of oscillation. We conclude that human and murine BMSCs represent a valid in vitro model for the analysis of circadian mechanisms in bone metabolism and stem cell biology.
authors.affiliation: Stem Cell Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA, USA.
authors.forename: Xiying
authors.initials: X
authors.lastname: Wu
authors.forename: Gang
authors.initials: G
authors.lastname: Yu
authors.forename: Helen
authors.initials: H
authors.lastname: Parks
authors.forename: Teddi
authors.initials: T
authors.lastname: Hebert
authors.forename: Brian C
authors.initials: BC
authors.lastname: Goh
authors.forename: Marilyn A
authors.initials: MA
authors.lastname: Dietrich
authors.forename: Gadi
authors.initials: G
authors.lastname: Pelled
authors.forename: Reza
authors.initials: R
authors.lastname: Izadpanah
authors.forename: Dan
authors.initials: D
authors.lastname: Gazit
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Bunnell
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Gimble
mesh_terms: D056930:ARNTL Transcription Factors; D000328:Adult; D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics; D002940:Circadian Rhythm / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics; D003907:Dexamethasone / Q000494:pharmacology*; D005260:Female; D015870:Gene Expression / Q000187:drug effects*; D006801:Humans; D018021:Lithium Chloride / Q000494:pharmacology; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D009687:Nuclear Proteins / Q000235:genetics; D056953:Nuclear Receptor Subfamily 1, Group D, Member 1; D056950:Period Circadian Proteins; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics
chemical_list: D056930:ARNTL Transcription Factors; D015703:Antigens, CD; D051792:Basic Helix-Loop-Helix Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D003907:Dexamethasone; D018021:Lithium Chloride; D009687:Nuclear Proteins; D056953:Nuclear Receptor Subfamily 1, Group D, Member 1; D056950:Period Circadian Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D012097:Repressor Proteins; D014157:Transcription Factors; C538960:BMAL1 protein, human; C538961:Bmal1 protein, mouse; C063898:DBP protein, human; C498260:Dbp protein, mouse; C064353:NR1D1 protein, human; C090977:NR1D2 protein, human; C498262:Nr1d1 protein, mouse; C499650:Nr1d2 protein, mouse; C539022:PER1 protein, human; C512644:PER3 protein, human; C539023:Per1 protein, mouse; C512645:Per3 protein, mouse