Parathyroid tissue transcriptome over 24h of PTHcre;Bmal1 flox/flox mice and of Bmal1 flox/flox mice

The objective is to elucidate the role of the circadian clock in the parathyroid glands. We investigate the parathyroid transcriptome of wildtype mice (Bmal1 flox/flox) and of mice with parathyroid-specific excision of the circadian clock gene Bmal1 (PTHcre;Bmal1 flox/flox) harvested at 4 hour interval for 24 hours. Rhythmic genes were identified by JTK_CYCLE analysis and revealed 1455 rhythmic genes of the Bmal1 flox/flox and 1055 rhythmic genes of the PTHcre;Bmal1 flox/flox. We found global damepning of circadian clock genes with abolished rhythmicity of Cry1, Cry2, Clock, Npas2, Rorc, and Usp2. We used GSEA analysis to investigate differential expression at each timepount and found downregulation of genes involved in ATP synthesis in PTHcre;Bmal1 flox/flox mice at 4 consecutive timepoints during the active period of the mouse. Samples are pooled parathyroid glands from two mice of either Bmal1 flox/flox (WT) or PTHcre;Bmal1 flox/flox (KO) genotype. Samples were collected at 6 timepoints with 4 hour interval starting when lights turn on at zeitgebertime (=ZT) 0. In total 21 samples from WT and 18 samples from KO were collected.本研究旨在阐明甲状旁腺中生物钟的作用。我们对野生型小鼠（Bmal1 flox/flox）以及甲状旁腺特异性敲除生物钟基因Bmal1的小鼠（PTHcre;Bmal1 flox/flox）的甲状旁腺转录组展开分析，采样间隔为4小时，覆盖完整24小时周期。通过JTK_CYCLE分析鉴定节律基因，结果显示Bmal1 flox/flox组存在1455个节律基因，PTHcre;Bmal1 flox/flox组存在1055个节律基因。我们观察到生物钟基因整体节律振幅衰减，且Cry1、Cry2、Clock、Npas2、Rorc及Usp2的节律性完全消失。我们采用基因集富集分析（Gene Set Enrichment Analysis, GSEA），对每个时间点的差异表达情况进行探究，结果发现：在小鼠活动期的4个连续时间点中，PTHcre;Bmal1 flox/flox小鼠体内参与ATP合成的基因均出现下调。实验样本为同基因型小鼠（Bmal1 flox/flox，即野生型WT；PTHcre;Bmal1 flox/flox，即敲除型KO）的2只小鼠的甲状旁腺混合组织。采样始于光照开启时刻（授时因子时间（zeitgebertime, ZT）0），共设置6个时间点，时间间隔为4小时。最终共收集到野生型样本21份，敲除型样本18份。