Dataset Information

Cold-induced suspension and resetting of Ca²⁺ and transcriptional rhythms in the suprachiasmatic nucleus neurons.

ABSTRACT: Does the circadian clock keep running under such hypothermic states as daily torpor and hibernation? This fundamental question has been a research subject for decades but has remained unsettled. We addressed this subject by monitoring the circadian rhythm of clock gene transcription and intracellular Ca²⁺ in the neurons of the suprachiasmatic nucleus (SCN), master circadian clock, in vitro under a cold environment. We discovered that the transcriptional and Ca²⁺ rhythms are maintained at 22°C-28°C, but suspended at 15°C, accompanied by a large Ca²⁺ increase. Rewarming instantly resets the Ca²⁺ rhythms, while transcriptional rhythms reach a stable phase after the transient state and recover their phase relationship with the Ca²⁺ rhythm. We conclude that SCN neurons remain functional under moderate hypothermia but stop ticking in deep hypothermia and that the rhythms reset after rewarming. These data also indicate that stable Ca²⁺ oscillation precedes clock gene transcriptional rhythms in SCN neurons.

SUBMITTER: Enoki R

PROVIDER: S-EPMC10700853 | biostudies-literature | 2023 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Cold-induced suspension and resetting of Ca2+ and transcriptional rhythms in the suprachiasmatic nucleus neurons.

Enoki Ryosuke R Kon Naohiro N Shimizu Kimiko K Kobayashi Kenta K Hiro Sota S Chang Ching-Pu CP Nakane Tatsuto T Ishii Hirokazu H Sakamoto Joe J Yamaguchi Yoshifumi Y Nemoto Tomomi T

iScience 20231103 12

Does the circadian clock keep running under such hypothermic states as daily torpor and hibernation? This fundamental question has been a research subject for decades but has remained unsettled. We addressed this subject by monitoring the circadian rhythm of clock gene transcription and intracellular Ca2+ in the neurons of the suprachiasmatic nucleus (SCN), master circadian clock, in vitro under a cold environment. We discovered that the transcriptional and Ca2+ rhyt ...[more]

PMID: 38077129

Similar Datasets

Project description:In mammals, the suprachiasmatic nucleus (SCN) of the hypothalamus coordinates daily rhythms including sleep-wake, hormone release, and gene expression. The cells of the SCN must synchronize to each other to drive these circadian rhythms in the rest of the body. The ontogeny of circadian cycling and intercellular coupling in the SCN remains poorly understood. Recent in vitro studies have recorded circadian rhythms from the whole embryonic SCN. Here, we tracked the onset and precision of rhythms in PERIOD2 (PER2), a clock protein, within the SCN isolated from embryonic and postnatal mice of undetermined sex. We found that a few SCN cells developed circadian periodicity in PER2 by 14.5 d after mating (E14.5) with no evidence for daily cycling on E13.5. On E15.5, the fraction of competent oscillators increased dramatically corresponding with stabilization of their circadian periods. The cells of the SCN harvested at E15.5 expressed sustained, synchronous daily rhythms. By postnatal day 2 (P2), SCN oscillators displayed the daily, dorsal-ventral phase wave in clock gene expression typical of the adult SCN. Strikingly, vasoactive intestinal polypeptide (VIP), a neuropeptide critical for synchrony in the adult SCN, and its receptor, VPAC2R, reached detectable levels after birth and after the onset of circadian synchrony. Antagonists of GABA or VIP signaling or action potentials did not disrupt circadian synchrony in the E15.5 SCN. We conclude that endogenous daily rhythms in the fetal SCN begin with few noisy oscillators on E14.5, followed by widespread oscillations that rapidly synchronize on E15.5 by an unknown mechanism.SIGNIFICANCE STATEMENT We recorded the onset of PER2 circadian oscillations during embryonic development in the mouse SCN. When isolated at E13.5, the anlagen of the SCN expresses high, arrhythmic PER2. In contrast, a few cells show noisy circadian rhythms in the isolated E14.5 SCN and most show reliable, self-sustained, synchronized rhythms in the E15.5 SCN. Strikingly, this synchrony at E15.5 appears before expression of VIP or its receptor and persists in the presence of blockers of VIP, GABA or neuronal firing. Finally, the dorsal-ventral phase wave of PER2 typical of the adult SCN appears ∼P2, indicating that multiple signals may mediate circadian synchrony during the ontogeny of the SCN.

Dataset Information

Cold-induced suspension and resetting of Ca²⁺ and transcriptional rhythms in the suprachiasmatic nucleus neurons.

Publications

Cold-induced suspension and resetting of Ca<sup>2+</sup> and transcriptional rhythms in the suprachiasmatic nucleus neurons.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets