Transcriptomics in the wild: hibernation physiology in free‐ranging dwarf lemurs

Hibernation is an adaptive strategy some mammals use to survive highly seasonal or unpredictable environments. We present the first investigation on the transcriptomics of hibernation in a natural population of primate hibernators: Crossley's dwarf lemurs (Cheirogaleus crossleyi). Using capture–mark–recapture techniques to track the same animals over a period of 7 months in Madagascar, we used RNA‐seq to compare gene expression profiles in white adipose tissue (WAT) during three distinct physiological states. We focus on pathway analysis to assess the biological significance of transcriptional changes in dwarf lemur WAT and, by comparing and contrasting what is known in other model hibernating species, contribute to a broader understanding of genomic contributions of hibernation across Mammalia. The hibernation signature is characterized by a suppression of lipid biosynthesis, pyruvate metabolism and mitochondrial‐associated functions, and an accumulation of transcripts encoding ribosomal components and iron‐storage proteins. The data support a key role of pyruvate dehydrogenase kinase isoenzyme 4 (PDK4) in regulating the shift in fuel economy during periods of severe food deprivation. This pattern of PDK4 holds true across representative hibernating species from disparate mammalian groups, suggesting that the genetic underpinnings of hibernation may be ancestral to mammals.

冬眠是部分哺乳动物为适应高度季节性或不可预测环境演化出的适应性生存策略。本研究首次针对灵长类冬眠动物自然种群的冬眠转录组学（transcriptomics）展开探究，研究对象为克罗斯利倭狐猴（Cheirogaleus crossleyi）。本研究在马达加斯加通过捕获-标记-重捕（capture–mark–recapture）技术对同一批动物开展了7个月的追踪，并利用RNA测序（RNA-seq）对比了三种不同生理状态下白色脂肪组织（WAT）的基因表达谱。本研究聚焦通路分析（pathway analysis），以评估倭狐猴白色脂肪组织中转录变化的生物学意义；同时通过与其他经典冬眠模式物种的已有研究进行对比，为深化对哺乳纲（Mammalia）冬眠的基因组调控机制的认知提供支撑。冬眠转录特征表现为脂质生物合成、丙酮酸代谢及线粒体相关功能的抑制，同时编码核糖体组分与铁储存蛋白的转录本丰度升高。本研究数据证实，丙酮酸脱氢酶激酶同工酶4（PDK4）在极端食物匮乏时期调控机体燃料代谢转换过程中发挥关键作用。这一PDK4调控模式在不同哺乳类类群的代表性冬眠物种中均成立，表明冬眠的遗传基础可能起源于哺乳类的共同祖先。