RNA-Sequencing Analysis Reveals l-Theanine Regulating Transcriptional Rhythm Alteration in Vascular Smooth Muscle Cells Induced by Dexamethasone

l-Theanine, a unique amino acid in tea leaves, is known to have beneficial effects on stress relief, tumor suppression, and prevention of hypertension and cardiovascular diseases (CADs). The disruption of the circadian rhythm has been implied in the pathogenesis of CADs. However, it is unknown whether l-theanine has a modulatory effect on the vascular circadian rhythm. In this research, we have established a circadian gene expression model in rat vascular smooth muscle cells by dexamethasone induction. l-Theanine treatment enhanced the expression amplitude of clock genes, including Bmal1, Cry1, Rev-erbα, and Per2. Moreover, pairwise comparisons of the RNA-sequencing data showed that l-theanine is able to upregulate a ray of the rhythm genes and differentially expressed genes that are involved in vasoconstriction and actin cytoskeleton regulation pathways. Our data suggest that l-theanine changes the circadian gene rhythm involving in the process of vascular smooth muscle restructure.