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Timed Exercise and Clocks: Does a Minimally Functional Suprachiasmatic Clock Support 24h Behavioral Rhythms?

ABSTRACT: The brain’s suprachiasmatic nucleus (SCN) is the master clock driving circadian rhythms in mammals. Vasoactive intestinal polypeptide (VIP) and its cognate receptor, VPAC2, are expressed in SCN neurons and mice with genetically targeted deletion of VPAC2 (Vipr2 -/-animals) show aberrant resetting to light, abnormal behavioral rhythms, and diminished SCN clock gene expression. Timed daily access to a running-wheel (scheduled voluntary exercise; SVE) promotes Vipr2 -/- SCN clock cell synchrony and 24h behavioral rhythms. We hypothesized that timed exercise alters the SCN transcriptome. Here, in control (Vipr2+/+) and Vipr2-/- mice under freely exercising and SVE conditions, RNAseq and qRT-PCR were used to measured gene expression of laser-dissected SCN. Compared to Vipr2+/+ mice, hundreds of genes were differentially expressed in the SCN from Vipr2-/- mice rhythmic in the freely exercising condition. Unexpectedly, SVE did not promote a Vipr2+/+-like SCN transcriptome in Vipr2-/- mice and many transcripts involved in SCN function including Avp, C1ql3, Gpr176, Prok2, Sst, Per2, and Nr1d1 remained dysregulated in the SVE condition. By contrast, circadian oscillators in the liver and lung were mostly intact in Vipr2-/- mice. This study indicates that marked molecular deficits in the SCN are sustained in behaviorally rhythmic Vipr2-/- mice, raising the possibility that a minimal functional SCN circadian clock can underpin whole animal rhythms.

ORGANISM(S): Mus musculus

PROVIDER: GSE207992 | GEO | 2023/01/20

REPOSITORIES: GEO

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Timed Exercise and Clocks: Does a Minimally Functional Suprachiasmatic Clock Support 24h Behavioral Rhythms?

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