南方医科大学学报

南方医科大学学报 ›› 2022, Vol. 42 ›› Issue (8): 1159-1165.doi: 10.12122/j.issn.1673-4254.2022.08.07

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寒冷胁迫可降低秀丽隐杆线虫的寿命和活动能力：通过介导脂代谢紊乱和应激反应异常

石 皓，张 超，赵嘉敏，李逸文，李允家，李俊杰，曾志云，高 磊   

  1. 南方医科大学中医药学院，基础医学院生化教研室，广东 广州 510515
  • 出版日期:2022-08-20 发布日期:2022-09-05

Cold stress reduces lifespan and mobility of C. elegans by mediating lipid metabolism disorder and abnormal stress response

SHI Hao, ZHANG Chao, ZHAO Jiamin, LI Yiwen, LI Yunjia, LI Junjie, ZENG Zhiyun, GAO Lei   

  1. School of Traditional Chinese Medicine, Department of Biochemistry, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
  • Online:2022-08-20 Published:2022-09-05

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摘要： 目的 探究秀丽隐杆线虫成虫在低温环境下的脂代谢、应激反应变化。方法 将同步化后的野生型及基因修饰型秀丽隐杆线虫成虫随机分为对照组和实验组，分别在20 ℃适宜条件和4 ℃低温暴露培养，观察其生存率、活动能力，评估非冷冻性极端低温对秀丽隐杆线虫成虫的寿命和活动能力影响；通过油红O染色和脂代谢相关基因表达检测，评价低温状态下秀丽隐杆线虫成虫脂代谢变化；通过线粒体荧光染色，应激相关基因、蛋白，抗氧化相关基因、蛋白的表达水平变化评估低温对秀丽隐杆线虫应激水平的影响。结果 4 ℃低温环境显著降低秀丽隐杆线虫成虫寿命（P<0.0001）和活动能力（P<0.0001）；同时，降低虫体脂质累积（P<0.05），降低脂肪酸合成和代谢相关基因fat-5，fat-6，fat-7，fasn-1，nhr-49，acs-2，aco-1表达 (P<0.01）；低温增强了热休克蛋白hsp-70，hsp-16.2表达(P<0.05），但是降低了线虫线粒体数目（P<0.0001）和线粒体未折叠蛋白反应相关蛋白atfs-1的表达(P< 0.05），降低了抗氧化酶sod-2，sod-3，gpx-1表达（P<0.01）。敲除秀丽隐杆线虫fat-5基因，或nhr-49基因，或同时敲除fat-5和fat-6基因能够加重寒冷导致的活动能力抑制（P<0.05），并显著降低虫体24 h生存率（P<0.0001）。结论 4 ℃非冷冻性低温使得秀丽隐杆线虫线虫成虫转变为低物质代谢和低能量代谢的状态，出现脂肪代谢水平降低，线粒体数量和质控能力降低，进一步诱发应激相关基因高表达和抗氧化酶含量降低，导致秀丽隐杆线虫活动能力和寿命降低。

关键词: 寒冷胁迫；秀丽隐杆线虫；脂代谢；应激

Abstract: Objective To investigate the changes of lipid metabolism and stress response of adult C. elegans exposed to non-freezing low temperature and explore the possible mechanism. Methods The survival rate and activity of adult C. elegans cultured at 20 ℃ or 4 ℃ were observed. Lipid metabolism of the cultured adult C. elegans was evaluated using oil red O staining and by detecting the expressions of the genes related with lipid metabolism. The effects of low temperature exposure on stress level of adult C. elegans were evaluated using mitochondrial fluorescence staining and by detecting the expression levels of stress-related genes and antioxidant genes at both the mRNA and protein levels. Results The lifespan and activity of adult C. elegans exposed to low temperature were significantly reduced with decreased lipid accumulation (P<0.05) and decreased expressions of genes related with fatty acid synthesis and metabolism (fat-5, fat-6, fat-7, fasn-1, nhr-49, acs-2 and aco-1; P<0.01). Cold stress significantly increased the expressions of heat shock proteins hsp-70 and hsp16.2 (P<0.05) but lowered the number of mitochondria (P<0.0001) and the expressions of atfs-1, sod-2, sod-3 and gpx-1 (P<0.05). Knockout of fat-5, nhr-49 or both fat-5 and fat-6 obviously enhanced the sensitivity of C. elegans to cold stress as shown by further reduced activity (P<0.05) and reduced survival rate at 24 h (P<0.0001) under cold stress. Conclusion Exposure to a low temperature at 4 ℃ results in lowered lipid metabolism of adult C. elegans accompanied by a decreased mitochondrial number and quality control ability, which triggers high expressions of stress-related genes and causes reduction of antioxidant capacity, thus callsing lowered activity and reduced lifespan of C. elegans.

Key words: cold stress; C. elegans; lipid metabolism; stress response