Integration of the nuclear receptor REV-ERBα linked with circadian oscillators in the expressions of Alas1, Ppargc1a, and Il6 genes in rat granulosa cells. (July 2015)

• Record Type: Journal Article
• Authors: Chen, Huatao; Isayama, Keishiro; Kumazawa, Makoto; Zhao, Lijia; Yamauchi, Nobuhiko; Shigeyoshi, Yasufumi; Hashimoto, Seiichi; Hattori, Masa-aki
• Is Part Of: Chronobiology international. Volume 32:Number 6(2015)
• Page Start: 739
• Page End: 749
• Publication Date: 2015-07
• Subjects: Chronobiology -- Periodicals; Biological rhythms -- Periodicals; Circadian rhythms -- Periodicals; 571.77
• DOI: 10.3109/07420528.2015.1042582
• Languages: English
• ISSNs: 0742-0528

Abstract

<abstract> <title> <x xml:space="preserve">Abstract</x> </title> <p>The nuclear receptor REV-ERBα links circadian rhythms and numerous physiological processes, but its physiological role in ovaries remains largely unknown. The aim of this study was to determine the potential role of REV-ERBα in the regulation of the transcription of its putative target genes in granulosa cells (GCs) prepared from <italic>Per2-destablized luciferase</italic> (<italic>dLuc</italic>) reporter gene transgenic rats. <italic>Alas1, Ppargc1a</italic>, and <italic>Il6</italic> were chosen as representatives for genes analysis. A real-time monitoring system of <italic>Per2</italic> promoter activity was performed to detect <italic>Per2-dLuc</italic> circadian oscillations. Two agonists (GSK4112, heme) and an antagonist (SR8278) of REV-ERBα as well as <italic>Rev-erbα</italic> siRNA knockdown were used to identify its target genes. Clear <italic>Per2-dLuc</italic> circadian oscillations were generated in matured GCs after synchronization with GSK4112 or SR8278. GSK4112 treatment lengthened and SR8278 treatment shortened the period of circadian oscillations in matured GCs stimulated with or without luteinizing hormone (LH). GSK4112 showed an inhibitory effect on the amplitude of circadian oscillations and caused an arrhythmic expression of canonical clock genes. SR8278 also had a subtle effect on their daily expression profiles, but the treatment resulted only in the arrhythmic expression of <italic>Rev-erbα</italic>. These findings indicate the functional biological activity of REV-ERBα in response to its ligands. Its natural ligand heme further elongated the period of circadian oscillations and alleviated their amplitudes in GCs cultured with LH. Heme treatment also repressed the expressions of clock genes, <italic>Alas1, Il6</italic>, and <italic>Ppargc1a. Rev-erbα</italic> knockdown up-regulated these transcript levels. Collectively, these data extend the recent finding to rat GCs and demonstrate that REV-ERBα represses the expressions of <italic>Alas1, Ppargc1a</italic>, and <italic>Il6</italic>, providing novel insights into the physiological significance of REV-ERBα in ovarian circadian oscillators.</p> </abstract>