Circadian Rhythm

2022-07-18: reference:

Circadian Rhythm #

• It goes something like this: Redundant Function of REV-ERBα and β and Non-Essential Role for Bmal1 Cycling in Transcriptional Regulation of Intracellular Circadian Rhythms
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  • BMAL1-CLOCK complex activates Cryptochrome- [Per] dimer complex. It inhibits BMAL1-CLOCK, making a loop.
    • BMAL1-CLOCK has an intronic E-box enhancer that drives rhythmicity. E-box mediated transcription also drives Rev-Erb.
      • This is kind of interesting: https://en.wikipedia.org/wiki/E-box?useskin=vector.
    • And then they produce the CCGs which can either promote or repress… (redundant images but this is kind of a mess, is it not?)

• A role for nuclear receptors in mammalian hybernation
  • RORα: also regulates ApoA-I, ApoC-III, Rev-Erbα, CYP7B1, and SULT-2A1
  • Rev-Erbα regulates ApoA-I, ApoC-III, CYP7A1, and TLR4.
• This is for mice. Is it inverted for humans or something?

Metabolism #

• Circadian clocks and neurodegenerative diseases: time to aggregate?

• Circadian molecular clocks and cancer

• Time of Day and Muscle Strength: A Circadian Output?

  • Maximal isometric force between 4-8, something like a 4-13% increase compared to the morning.
  • Core body temperature (itself correlated with strength, of course) peaks ~1°C at 5-7.
  • Each tissue has its own circadian clock output.

• Trichromatic vision is not necessary for light-mediated neuroendocrine regulation.

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• WTF? Cones Support Alignment to an Inconsistent World by Suppressing Mouse Circadian Responses to the Blue Colors Associated with Twilight

  • Contrary to common beliefs, it is yellow rather than blue colors that have the strongest effect on the mammalian circadian system.

Nutrition #

• Circadian autophagy drives iTRF-mediated longevity
  • Night-specific induction of autophagy was both necessary and sufficient to extend lifespan on an ad libitum diet and also prevented further iTRF-mediated lifespan extension. By contrast, day-specific induction of autophagy did not extend lifespan.
    • This is in Drosophila, which are crepuscular, meaning they are active during twilight periods of dawn and dusk. It’s not exactly nocturnal, but I suppose you can extrapolate this to humans during the daytime; perhaps the afternoon?