Cinnamon polyphenol extract and insulin regulate diacylglycerol acyltransferase gene expression in mouse adipocytes and macrophages

Authors: Cao, Heping; Sethumadhavan, Kandan; LI, KE - Shanxi University; Boue, Stephen; ANDERSON, RICHARD - Retired ARS Employee

Submitted to: Plant Foods for Human Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/16/2018
Publication Date: 1/14/2019
Citation: Cao, H., Sethumadhavan, K., Li, K., Boue, S.M., Anderson, R.A. 2019. Cinnamon polyphenol extract and insulin regulate diacylglycerol acyltransferase gene expression in mouse adipocytes and macrophages. Plant Foods for Human Nutrition. 74(1):115-121. https://doi.org/10.1007/s11130-018-0709-7.
DOI: https://doi.org/10.1007/s11130-018-0709-7

Interpretive Summary: Plant bioactive polyphenols have been used for the prevention and treatment of various diseases since ancient history. Cinnamon is a small evergreen tree (10-15 m tall) with greenish flowers. It was described in the Chinese texts 4,000 years ago and imported to Egypt 2000BC. Common has a long history of uses as spices, flavoring agents, preservatives, and pharmacological agents. Recent studies have demonstrated that cinnamon polyphenol extract (CPE) may be important in the alleviation of chronic diseases. However, the molecular evidence is not substantial. The objective of this study was to explore the molecular effects of CPE and insulin on the regulation of DGAT gene expression and compared to TTP gene expression in cultured adipocytes and macrophages. qPCR was used to investigate the effects of CPE and insulin on the expression of DGAT1, DGAT2 and TTP mRNAs in mouse 3T3-L1 adipocytes (a widely used cell model for mechanistic studies of lipid metabolism) and RAW264.7 macrophages (a commonly used cell model for inflammation studies). This study demonstrated that CPE and insulin rapidly affected DGAT and TTP mRNA levels in the cultured adipocytes and macrophages. We conclude that CPE and insulin exhibited overlapping and independent effects on DGAT and TTP gene expression and suggest that CPE and insulin have profound effects on fat biosynthesis and inflammatory responses in mouse adipocytes and macrophages.

Technical Abstract: Cinnamon polyphenol extract (CPE) improves people with insulin resistance. The objective was to investigate CPE and insulin effects on gene expression of diacylglycerol acyltransferase (DGAT) and tristetraprolin (TTP) important for lipid biosynthesis and anti-inflammatory responses. Cultured mouse adipocytes and macrophages were treated with insulin and CPE followed by TaqMan qPCR evaluation of DGAT1, DGAT2 and TTP mRNA levels. Insulin decreased DGAT1 and DGAT2 mRNA levels in adipocytes but had no effect on DGAT1 in macrophages and increased DGAT2 mRNA levels 3-fold in macrophages. Insulin increased TTP mRNA levels 3.5-fold in adipocytes but no effect in macrophages. CPE effect on DGAT1 gene expression was minimal but increased DGAT2 mRNA levels 2-fold in adipocytes and 4-fold in macrophages. CPE increased TTP mRNA levels 7-fold in adipocytes and 2.4-fold in macrophages. We conclude that CPE and insulin exhibited overlapping and independent effects on DGAT and TTP gene expression and suggest that CPE and insulin have profound effects on fat biosynthesis and inflammatory responses in mouse adipocytes and macrophages.