L-theanine Modulates The Circadian Rhythm Of Vascular Smooth Muscle

The blood pressure of healthy human body has circadian rhythm.Vasoconstriction and relaxation are closely related to vascular smooth muscle.Studies have shown that tea drinking can reduce blood pressure,but whether L-theanine,a functional component of tea,can regulate the biological rhythm of smooth muscle has not been reported.It is of great significance to explore the biological rhythm of theanine regulating vascular smooth muscle for further understanding of blood pressure homeostasis and body health.In this study,a cell model of dexamethasone induced gene rhythm expression in vascular smooth muscle cells was established,and the in vitro and in vivo fluorescence detection was carried out in PER2::LUC mice to explore the regulatory effect of Ltheanine on gene expression of vascular smooth muscle rhythm.The main results are as follows:1.The core biological clock genes Bmal1,Reverba,Per2,Cry1 and Npas2 of vascular smooth muscle cells showed rhythmic expression of about 24 hours after induction of dexamethasone at 100nM and 15min.The expression amplitude of Bmal1,Per2,Cry1,Npas2 gene mRNA were significantly enhanced by L-theanine.2.Transcriptome sequencing revealed that L-theanine upregulated 1691 genes and decreased 181 genes in VSMCs.Among them,L-theanine intervention significantly reduced the rhythmic expression of Rock2,CPI-17 mRNA and protein related to vasoconstriction.The regulatory mechanism may be that L-theanine inhibits rock2 and cpi17 expression by enhancing the high expression of Bmal1 gene.3.The biorhythm fluorescence of aortic vessels and mesenteric artery of PER2::LUC mice was detected in vitro and ex vivo.The results showed that L-theanine enhanced the amplitude of fluorescence expression in tissues,and the expression of melatonin in plasma of aged mice was significantly increased by intragastric administration of L-theanine.4.The expression level of Cryl in VSMCs with knockout of Bmal1 gene had no significant change.However,the expression of CRY1 increased significantly when the Bmall gene in VSMCs was overexpressed by adenovirus.The results showed that L-theanine may target Bmall gene and regulate the expression of downstream gene.