Hypothalamic remodeling of thyroid hormone signaling during hibernation in the arctic ground squirrel

作者：Helen E. Chmura, Cassandra Duncan, Ben Saer, Jeanette T. Moore, Brian M. Barnes, Charles Loren Buck, Helen Christian, Andrew S. I. Loudon, Cory T. Williams · 发表于：Communications Biology · 年份：2022 · DOI：10.1038/s42003-022-03431-8 · 被引用次数：23 · 研究领域：Bat Biology and Ecology Studies、Neuroendocrine regulation and behavior、Circadian rhythm and melatonin

Hibernation involves prolonged intervals of profound metabolic suppression periodically interrupted by brief arousals to euthermy, the function of which is unknown. Annual cycles in mammals are timed by a photoperiodically-regulated thyroid-hormone-dependent mechanism in hypothalamic tanycytes, driven by thyrotropin (TSH) in the pars tuberalis (PT), which regulates local TH-converting deiodinases and triggers remodeling of neuroendocrine pathways. We demonstrate that over the course of hibernation in continuous darkness, arctic ground squirrels (Urocitellus parryii) up-regulate the retrograde TSH/Deiodinase/TH pathway, remodel hypothalamic tanycytes, and activate the reproductive axis. Forcing the premature termination of hibernation by warming animals induced hypothalamic deiodinase expression and the accumulation of secretory granules in PT thyrotrophs and pituitary gonadotrophs, but did not further activate the reproductive axis. We suggest that periodic arousals may allow for the transient activation of hypothalamic thyroid hormone signaling, cellular remodeling, and re-programming of brain circuits in preparation for the short Arctic summer.