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Liu A, Lin L, Xu W, Gong Z, Liu Z, Xiao W. L-Theanine regulates glutamine metabolism and immune function by binding to cannabinoid receptor 1. Food Funct 2021; 12:5755-5769. [PMID: 34037653 DOI: 10.1039/d1fo00505g] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
l-Theanine is a characteristic amino acid in tea with various effects including antioxidant and anti-inflammatory effects. Previously, most studies had reported that l-theanine regulates the immune function in vivo by inhibiting the expression of the inflammatory factors, but how l-theanine regulates the inflammatory factors' pathway is not known. In this study, we innovatively found the binding target of l-theanine in vivo-cannabinoid receptor 1, and demonstrated that l-theanine regulated the immune function and glutamine metabolism by competitively binding cannabinoid receptor 1. Mechanistically, l-theanine competitively binds cannabinoid receptor 1, leading to inhibition of cannabinoid receptor 1 activity, and regulates glutamine metabolism and immune function in normal and E44813-stressed rats. In normal rats, l-theanine inhibits ERK1/2 phosphorylation through Gβy by antagonizing cannabinoid receptor 1, thus affecting GS expression. From the point of view of immune signaling, after LTA antagonizes the activity of cannabinoid receptor 1, it relieves the inhibition of cannabinoid receptor 1 on COX-2 expression, downregulates Pdcd4 expression and NFκB, and ultimately enhances the expression of the anti-inflammatory factor IL-10. In E44813-stressed rats, l-theanine promotes the nuclear translocation of p-ERK1/2 by inhibiting the activity of cannabinoid receptor 1, and finally acts on GS. At the same time, it decreases the expression of the pro-inflammatory factor TNF-α and increases the expression of the anti-inflammatory factor IL-10 in stressed rats through the COX2-Pdcd4-NFκB-IL10 and TNFα pathways. In summary, these results demonstrate that l-theanine regulates glutamine metabolism and immune function by competitively binding to cannabinoid receptor 1.
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Affiliation(s)
- An Liu
- Key Lab of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha, Hunan 410128, China. and National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha, Hunan 410128, China and Hunan Agricultural University, Co-Innovation Center of Education Ministry for Utilization of Botanical Functional Ingredients, Changsha, Hunan 410128, China
| | - Ling Lin
- Key Lab of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha, Hunan 410128, China. and National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha, Hunan 410128, China and Hunan Agricultural University, Co-Innovation Center of Education Ministry for Utilization of Botanical Functional Ingredients, Changsha, Hunan 410128, China
| | - Wei Xu
- Key Lab of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha, Hunan 410128, China. and National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha, Hunan 410128, China and Hunan Agricultural University, Co-Innovation Center of Education Ministry for Utilization of Botanical Functional Ingredients, Changsha, Hunan 410128, China
| | - Zhihua Gong
- Key Lab of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha, Hunan 410128, China. and National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha, Hunan 410128, China and Hunan Agricultural University, Co-Innovation Center of Education Ministry for Utilization of Botanical Functional Ingredients, Changsha, Hunan 410128, China
| | - Zhonghua Liu
- Key Lab of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha, Hunan 410128, China. and National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha, Hunan 410128, China and Hunan Agricultural University, Co-Innovation Center of Education Ministry for Utilization of Botanical Functional Ingredients, Changsha, Hunan 410128, China
| | - Wenjun Xiao
- Key Lab of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha, Hunan 410128, China. and National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hunan Agricultural University, Changsha, Hunan 410128, China and Hunan Agricultural University, Co-Innovation Center of Education Ministry for Utilization of Botanical Functional Ingredients, Changsha, Hunan 410128, China
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