硫化氢在冬眠的 13 条地松鼠中抑制线粒体呼吸

Suppression of mitochondrial respiration by hydrogen sulfide in hibernating 13-lined ground squirrels.

Keywords：H2S, Hypometabolism, Ictidomys tridecemlineatus, Torpor, Sulfide:quinone oxidoreductase 

关键词：H2S，低代谢，Ictidomys tridecemlineatus，Torpor，硫化物：苯醌氧化还原酶；昏迷

组织：肝脏
作者：Jensen Birgitte S, Pardue Sibile, Duffy Brynne, Kevil Christopher G, Staples James F, Fago Angela

出版期刊：《 Free Radic Biol Med 》（2021年6月）

Abstract：

Hibernating mammals may suppress their basal metabolic rate during torpor by up to 95% to reduce energy expenditure during winter, but the underlying mechanisms remain poorly understood. Here we show that hydrogen sulfide (H2S), a ubiquitous signaling molecule, is a powerful inhibitor of respiration of liver mitochondria isolated from torpid 13-lined ground squirrels, but has a weak effect on mitochondria isolated during summer and hibernation arousals, where metabolic rate is normal. Consistent with these in vitro effects, we find strong seasonal variations of in vivo levels of H2S in plasma and increases of H2S levels in the liver of squirrels during torpor compared to levels during arousal and summer. The in vivo changes of liver H2S levels correspond with low activity of the mitochondrial H2S oxidizing enzyme sulfide:quinone oxidoreductase (SQR) during torpor. Taken together, these results suggest that during torpor, H2S accumulates in the liver due to a low SQR activity and contributes to inhibition of mitochondrial respiration, while during arousals and summer these effects are reversed, H2S is degraded by active SQR and mitochondrial respiration rates increase. This study provides novel insights into mechanisms underlying mammalian hibernation, pointing to SQR as a key enzyme involved in the control of mitochondrial function.

文章摘要：

冬眠的哺乳动物可能会在蛰伏期间将基础代谢率抑制高达 95%，以减少冬季的能量消耗，但其潜在机制仍知之甚少。在这里，我们表明硫化氢 (H 2 S) 是一种普遍存在的信号分子，它是从迟钝的 13 排地松鼠中分离出的肝线粒体呼吸的强大抑制剂，但对夏季和冬眠唤醒期间分离的线粒体影响较弱，其中代谢率正常。与这些体外效应一致，我们发现血浆中 H 2 S体内水平的强烈季节性变化和H 2增加与觉醒和夏季期间的水平相比，松鼠在麻木时肝脏中的 S 水平。肝脏H 2 S 水平的体内变化与休眠期间线粒体H 2 S 氧化酶硫化物：醌氧化还原酶（SQR）的低活性相对应。综上所述，这些结果表明，在麻木期间，由于 SQR 活性低，H 2 S 在肝脏中积累并有助于抑制线粒体呼吸，而在觉醒和夏季，这些作用被逆转，H 2S 被活性 SQR 降解，线粒体呼吸速率增加。这项研究为哺乳动物冬眠的机制提供了新的见解，指出 SQR 是参与控制线粒体功能的关键酶。

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