Dynamic Atlas and Energy Metabolism Adaptation of the Liver Proteome During a 24 h Cycle in Vespertilio sinensis

Circadian rhythms regulate hepatic metabolism and physiological homeostasis, which are essential for organisms to adapt to environmental cycles. Bats are the only mammals capable of sustained powered flight, accompanied by extreme metabolic demands and a nocturnal lifestyle. However, the regulatory mechanisms underlying hepatic circadian rhythms in bats remain poorly understood. Herein, we employed data-independent acquisition (DIA)-based quantitative proteomics to characterize the diurnal dynamics of hepatic proteins in Vespertilio sinensis across four representative physiological states, and further conducted integrative multi-omics analysis combined with transcriptomic data. The results revealed that approximately 5% of hepatic proteins exhibited circadian rhythmicity in V. sinensis, a proportion markedly higher than that of rhythmic transcripts and metabolites. Prominent transcription-protein rhythm decoupling was observed, implying that post-transcriptional regulatory processes may play critical roles in shaping circadian rhythms. Core metabolic pathways displayed temporally dynamic enrichment. The diurnal functional switching of the liver was achieved via stable expression of core proteins and temporal turnover of specific proteins, which efficiently coordinated energy supply, oxidative defense and detoxification metabolism. Trend clustering and functional enrichment analyses suggested that the liver may undergo lysosome-mediated immune repair during the daytime, while exhibiting enriched energy metabolic profiles that potentially support the elevated energy expenditure required for flight at night. This study systematically elucidates the protein regulatory patterns underlying hepatic diurnal rhythms in V. sinensis, and provides molecular clues for exploring extreme energy adaptation and circadian evolutionary scenarios in nocturnal flying mammals.