Gene expression plasticity of the mammalian brain circadian clock in response to photoperiod

ABSTRACT Seasonal daylength, or circadian photoperiod, is a pervasive environmental signal that profoundly influences physiology and behavior. In mammals, the central circadian clock resides in the suprachiasmatic nuclei (SCN) of the hypothalamus where it receives retinal input and synchronizes, or entrains, organismal physiology and behavior to the prevailing light cycle. The process of entrainment induces sustained plasticity in the SCN, but the molecular mechanisms underlying SCN plasticity are incompletely understood. Entrainment to different photoperiods persistently alters the timing, waveform, period, and light resetting properties of the SCN clock and its driven rhythms. To elucidate novel molecular mechanisms of photoperiod plasticity, we performed RNAseq on whole SCN dissected from mice raised in Long (LD 16:8) and Short (LD 8:16) photoperiods. Fewer rhythmic genes were detected in Long photoperiod and in general the timing of gene expression rhythms was advanced 4-6 hours. However, a few genes showed significant delays, includingGem. There were significant changes in the expression clock-associated geneTimelessand in SCN genes related to light responses, neuropeptides, GABA, ion channels, and serotonin. Particularly striking were differences in the expression of the neuropeptide signaling genesProkr2andCck, as well as convergent regulation of the expression of three SCN light response genes,Dusp4,Rasd1, andGem. Transcriptional modulation ofDusp4andRasd1,and phase regulation ofGem,are compelling candidate molecular mechanisms for plasticity in the SCN light response through their modulation of the critical NMDAR-MAPK/ERK-CREB/CRE light signaling pathway in SCN neurons. Modulation ofProkr2andCckmay critically support SCN neural network reconfiguration during photoperiodic entrainment. Our findings identify the SCN light response and neuropeptide signaling gene sets as rich substrates for elucidating novel mechanisms of photoperiod plasticity..

Medienart:

Preprint

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

bioRxiv.org - (2024) vom: 27. März Zur Gesamtaufnahme - year:2024

Sprache:

Englisch

Beteiligte Personen:

Cox, Olivia H. [VerfasserIn]
Gianonni-Guzmán, Manuel A. [VerfasserIn]
Cartailler, Jean-Philippe [VerfasserIn]
Cottam, Matthew A. [VerfasserIn]
McMahon, Douglas G. [VerfasserIn]

Links:

Volltext [kostenfrei]

Themen:

570
Biology

doi:

10.1101/2024.02.16.580759

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

XBI042645778