Yang Hui, Zhang Zubin, Ding Xin, Jiang Xiaolu, Tan Lanlan, Lin Chenjie, Xu Lixiao, Li Gen, Lu Lianghua, Qin Zhenghong, Feng Xing, Li Mei
Department of Pediatrics Research Institute, Children's Hospital of Soochow University, Suzhou, Jiangsu Province, China.
Department of Neonatology, Tongren People's Hospital, Tongren, Guizhou Province, China.
J Pineal Res. 2023 Aug;75(1):e12885. doi: 10.1111/jpi.12885. Epub 2023 May 22.
Hypoxia-ischemia (HI) of the brain not only impairs neurodevelopment but also causes pineal gland dysfunction, which leads to circadian rhythm disruption. However, the underlying mechanism of circadian rhythm disruption associated with HI-induced pineal dysfunction remains unknown. The zinc finger protein repressor protein with a predicted molecular mass of 58 kDa (RP58) is involved in the development and differentiation of nerve cells. In this study, we established an HI model in neonatal rats to investigate the expression of RP58 and its role in pineal dysfunction and circadian rhythm disruption induced by HI. We demonstrated that RP58 was highly expressed in the pineal gland under normal conditions and significantly downregulated in the pineal gland and primary pinealocytes following HI. Knockdown of RP58 decreased the expression of enzymes in the melatonin (Mel) synthesis pathway (tryptophan hydroxylase 1 [TPH1], acetylserotonin O-methyltransferase [ASMT], and arylalkylamine N-acetyltransferase [AANAT]) and clock genes (circadian locomotor output cycles kaput [CLOCK] and brain and muscle ARNT-like 1 [BMAL1]), and it also reduced the production of Mel, caused pineal cell injury, and disrupted circadian rhythms in vivo and in vitro. Similarly, HI reduced the expression of Mel synthesis enzymes (TPH1, ASMT, and AANAT) and clock genes (CLOCK and BMAL1), and caused pineal injury and circadian rhythm disruption, which were exacerbated by RP58 knockdown. The detrimental effect of RP58 knockdown on pineal dysfunction and circadian rhythm disruption was reversed by the addition of exogenous Mel. Furthermore, exogenous Mel reversed HI-induced pineal dysfunction and circadian rhythm disruption, as reflected by improvements in Mel production, voluntary activity periods, and activity frequency, as well as a diminished decrease in the expression of Mel synthesis enzymes and clock genes. The present study suggests that RP58 is an endogenous source of protection against pineal dysfunction and circadian rhythm disruption after neonatal HI.
脑缺氧缺血（HI）不仅会损害神经发育，还会导致松果体功能障碍，进而引起昼夜节律紊乱。然而，与HI诱导的松果体功能障碍相关的昼夜节律紊乱的潜在机制仍不清楚。预测分子量为58 kDa的锌指蛋白阻遏蛋白（RP58）参与神经细胞的发育和分化。在本研究中，我们在新生大鼠中建立了HI模型，以研究RP58的表达及其在HI诱导的松果体功能障碍和昼夜节律紊乱中的作用。我们证明，在正常条件下RP58在松果体中高表达，而在HI后松果体和原代松果体细胞中显著下调。敲低RP58会降低褪黑素（Mel）合成途径中的酶（色氨酸羟化酶1 [TPH1]、乙酰血清素O-甲基转移酶[ASMT]和芳基烷基胺N-乙酰转移酶[AANAT]）和生物钟基因（昼夜运动输出周期蛋白[CLOCK]和脑与肌肉芳香烃受体核转运蛋白样蛋白1 [BMAL1]）的表达，还会减少Mel的产生，导致松果体细胞损伤，并在体内和体外破坏昼夜节律。同样，HI会降低Mel合成酶（TPH1、ASMT和AANAT）和生物钟基因（CLOCK和BMAL1）的表达，并导致松果体损伤和昼夜节律紊乱，而敲低RP58会加剧这些情况。添加外源性Mel可逆转敲低RP58对松果体功能障碍和昼夜节律紊乱的有害影响。此外，外源性Mel可逆转HI诱导的松果体功能障碍和昼夜节律紊乱，这表现为Mel产生、自主活动时间和活动频率的改善，以及Mel合成酶和生物钟基因表达下降的减少。本研究表明，RP58是新生儿HI后防止松果体功能障碍和昼夜节律紊乱的内源性保护源。
