Murakami Masaru, Ohi Masahiro, Ishikawa Shoko, Shirai Mitsuyuki, Horiguchi Hiroki, Nishino Yoshii, Funaba Masayuki
Laboratory of Molecular Biology, Azabu University School of Veterinary Medicine, Sagamihara 252-5201, Japan.
Laboratory of Molecular Biology, Azabu University School of Veterinary Medicine, Sagamihara 252-5201, Japan.
Comp Biochem Physiol A Mol Integr Physiol. 2015 Jul;185:142-9. doi: 10.1016/j.cbpa.2015.04.003. Epub 2015 Apr 10.
The expression of uncoupling protein (UCP1) is up-regulated in mammalian brown adipocytes during cold exposure. However, a previous study revealed that UCP1 was highly expressed in the liver of common carps, and that the hepatic expression of UCP1 was down-regulated during cold exposure. The present study examined the effects of temperature on the recovery of UCP1 expression levels and the expression of genes involved in UCP1 transcription in the livers and kidneys of common carps. The hepatic and renal expressions of UCP1 were decreased by acclimation from 22 °C to 8 °C, and a subsequent increase in the water temperature from 8 °C to 28 °C recovered the renal, but not hepatic expression of UCP1. Changes in the expression of peroxisome proliferator-activator receptor (PPAR) γ, retinoid X receptor (RXR) α and PPARγ co-activator (PGC)-1α, genes that are involved in the expression of UCP1 in mammals, with ambient temperature indicated that the expressions of PPARγ and RXRα, but not expression of PGC-1α was decreased in response to cold exposure; the hepatic and renal expressions of PPARγ and RXRα recovered to basal levels with the cessation of cold exposure, although this was not complete for hepatic expression of PPARγ. The results of the present study indicate that a unique regulatory mechanism is responsible for the hepatic and renal expressions of carp UCP1 during cold exposure and subsequent reacclimation, and is distinct from that in murine brown adipocytes.
在寒冷暴露期间，哺乳动物棕色脂肪细胞中解偶联蛋白（UCP1）的表达上调。然而，先前的一项研究表明，UCP1在鲤鱼肝脏中高表达，并且在寒冷暴露期间肝脏中UCP1的表达下调。本研究检测了温度对鲤鱼肝脏和肾脏中UCP1表达水平恢复以及参与UCP1转录的基因表达的影响。将水温从22℃驯化至8℃会使肝脏和肾脏中UCP1的表达降低，随后水温从8℃升高至28℃可使肾脏中UCP1的表达恢复，但肝脏中UCP1的表达未恢复。过氧化物酶体增殖物激活受体（PPAR）γ、视黄醇X受体（RXR）α和PPARγ共激活因子（PGC）-1α（这些基因参与哺乳动物UCP1的表达）的表达随环境温度变化表明，寒冷暴露会使PPARγ和RXRα的表达降低，但不会使PGC-1α的表达降低；随着寒冷暴露的停止，肝脏和肾脏中PPARγ和RXRα的表达恢复到基础水平，尽管肝脏中PPARγ的表达并未完全恢复。本研究结果表明，在寒冷暴露及随后的再驯化过程中，一种独特的调节机制负责鲤鱼肝脏和肾脏中UCP1的表达，且该机制与小鼠棕色脂肪细胞中的不同。
