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Insulin and Cinnamon Polyphenol Extract Regulated Diacylglycerol Acyltransferase and Tristetraprolin Gene Expression in Cultured Mouse Adipocytes and Macrophages
Author(s) -
Cao Heping,
Anderson Richard A
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.428.2
Subject(s) - tristetraprolin , diacylglycerol kinase , gene expression , chemistry , insulin , insulin resistance , messenger rna , lipid droplet , gene , microbiology and biotechnology , biochemistry , endocrinology , biology , enzyme , untranslated region , protein kinase c
Diacylglycerol acyltransferases (DGATs) are integral membrane proteins that catalyze the last step of triacylglycerols (TAGs) biosynthesis in eukaryotic organisms. Plants and animals deficient in DGATs accumulate less TAGs and over‐expression of DGATs increases TAGs. DGAT knockout mice are resistant to diet‐induced obesity and lack milk secretion. Previous studies showed that cinnamon is beneficial to people with insulin resistance due in part to the insulin‐like activity of the cinnamon polyphenol extract (CPE), which also induces anti‐inflammatory zinc‐finger protein 36 (Zfp36)/tristetraprolin (Ttp) gene expression in both cultured adipocytes and macrophages. This study tested if Dgat gene expression is regulated by insulin and CPE using cultured mouse 3T3‐L1 adipocytes and RAW264.7 macrophages. The pre‐adipocytes were induced to oil‐droplet‐filled adipocytes and subsequently treated with insulin (0, 10 and 100 nM) and CPE (0, 10 and 100 μg/ml) for 0, 30, 60, 90 and 120 min. RAW macrophages were treated with CPE (100 μg/ml), insulin (100 nM) and lipopolysaccharides (LPS, 0.1 μg/ml) for 0, 30, 60, 120 and 240 min. Total RNAs were extracted from the cells and converted into cDNAs. TaqMan quantitative real‐time PCR was used to evaluate mRNA levels of mouse Dgat1, Dgat2 and Zfp36/Ttp genes using Rpl32 and Ubqln3 as internal references. Results showed that Dgat mRNA levels were generally decreased and Zfp36/Ttp mRNA levels were modestly increased by insulin and CPE in adipoctyes. Insulin and CPE effects on Dgat2 and Zfp36/Ttp gene expression were modestly increased but LPS increased Zfp36/Ttp mRNA levels up to 50‐fold in macrophages. Our results support the idea that CPE has insulin‐like effects and suggest a potential positive effect of CPE in reducing fat biosynthesis in adipocytes and increasing anti‐inflammatory activities in macrophages. The significance of this study is that CPE could be potentially useful for obesity prevention. Support or Funding Information USDA‐ARS Quality and Utilization of Agricultural Products Research Program 306 through CRIS 6054‐41000‐103‐00D