Center for Basic Medical Research, International University of Health and Welfare, Ohtawara, Tochigi, Japan.
Department of Pharmacology, International University of Health and Welfare, Ohtawara, Tochigi, Japan.
Biochem Biophys Res Commun. 2020 Apr 2;524(2):497-501. doi: 10.1016/j.bbrc.2020.01.125. Epub 2020 Jan 31.
Circadian rhythms are a fundamental biological phenomena that control various physiological functions. The suprachiasmatic nucleus (SCN) is a master clock that integrates various peripheral clocks. Recently, the choroid plexus (CP) was reported to be one such peripheral clock, a circadian oscillator that might conversely affect the SCN. Hence, the principle aim of our study was to unravel the circadian oscillator within the CP. Quantitative PCR against rPer1, rPer2, and rBmal1 showed that CP in the lateral ventricle (CP-LV) and fourth ventricle (CP-4V) has a robust circadian oscillator. The phases of the CP oscillator are between those of the pineal gland (PG) and SCN. Bioluminescence monitoring of explants showed that the intrinsic circadian period of CP-LV and CP-4V was approximately 21 h, which is shorter than SCN and PG. It is possible that interaction between oscillators of the CP-LV, CP-4V, PG, and SCN ensures the SCN adopts a stable 24 h rhythm, with each of the regions having an intrinsic oscillator with different phases and periods. In situ hybridization analysis revealed that dusk-to-dawn variation of rPer2 expression was found in epithelial cells of the CP only. Furthermore, the CP circadian oscillator might control cerebrospinal fluid secretion. However, no dusk-to-dawn variation in expression of the water channel, aquaporin 1, was observed. Further investigations are needed to clarify the involvement of circadian rhythm on CP.
昼夜节律是控制各种生理功能的基本生物现象。视交叉上核（SCN）是整合各种外周时钟的主时钟。最近，脉络丛（CP）被报道为一种外周时钟，是一种昼夜振荡器，可能反过来影响 SCN。因此，我们研究的主要目的是揭示 CP 中的昼夜振荡器。针对 rPer1、rPer2 和 rBmal1 的定量 PCR 显示，侧脑室（CP-LV）和第四脑室（CP-4V）中的 CP 具有强大的昼夜振荡器。CP 振荡器的相位介于松果腺（PG）和 SCN 之间。外植体的生物发光监测显示，CP-LV 和 CP-4V 的内在昼夜周期约为 21 小时，短于 SCN 和 PG。CP-LV、CP-4V、PG 和 SCN 中的振荡器之间的相互作用可能确保 SCN 采用稳定的 24 小时节律，每个区域都有一个具有不同相位和周期的内在振荡器。原位杂交分析显示，只有 CP 的上皮细胞中发现 rPer2 表达的黄昏到黎明变化。此外，CP 昼夜振荡器可能控制脑脊液分泌。然而，水通道 aquaporin 1 的表达没有观察到黄昏到黎明的变化。需要进一步的研究来阐明 CP 昼夜节律的参与。
