Negative regulation of monocyte chemoattractant protein‐1 gene expression by a mouse estrogen‐enhanced transcript

• Published in: European journal of immunology 2002-10, Vol.32 (10), p.2837-2846
• Main Authors: Xie, Lai‐Ping, Fu, Wen‐Xian, Jin, Cong, Dong, Xue‐Yuan, Chen, Wei‐Feng
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Base Sequence; Cells, Cultured; Chemokine; Chemokine CCL2 - biosynthesis; Chemokine CCL2 - genetics; DNA, Complementary - analysis; Estradiol - pharmacology; Estrogen; Estrogen‐responsive element; Gene Expression Regulation - drug effects; Mice; Mice, Inbred BALB C; Molecular Sequence Data; NF-kappa B - metabolism; NF‐κB; Phosphoproteins; Response Elements - physiology; RNA, Messenger - analysis; Thymus stromal cell; Transcription, Genetic; Transcriptional Activation; Transfection
• ISSN: 0014-2980; 1521-4141
• DOI: 10.1002/1521-4141(2002010)32:10<2837::AID-IMMU2837>3.0.CO;2-V

A novel gene containing two typical estrogen responsive elements (ERE) was cloned from MTEC1 cells, a mouse thymus epithelial cell line that produces constitutively many chemokines. This geneis a homologue of the rat estrogen‐enhanced transcript (EET) gene, and is called the mEET gene. mEET protein is expressed in cytoplasm. Addition of 17 β‐estradiol (E2) to the MTEC1 cell cultures enhanced mEET mRNA expression and, meanwhile, significantly inhibited monocyte chemoattractant protein‐1 (MCP‐1) production. To analyze the functional links between the expression of mEET and of MCP‐1, we transfected MTEC1 cells with ERE‐deleted antisense‐ or sense‐mEET complementary (c)DNA construct and activated the transfected mEET cDNA in stable MTEC1 transfectants with doxycycline (Dox). Dox‐induced activation of the mEET gene profoundly inhibited MCP‐1 expression at both mRNA and protein levels and alleviated its chemotactic activity. Conversely, inactivation of the mEET gene substantially augmented MCP‐1 expression. Activation of the mEET gene markedly attenuated activity of nuclear NF‐κB. In summary, we have first demonstrated that estrogen‐imposed inhibition of MCP‐1 expression occurs through the activation of the mEET gene, its product suppresses nuclear NF‐κB and negatively regulates MCP‐1 gene activation.