PT  - JOURNAL ARTICLE
AU  - Elisa Tedeschi
AU  - Marta Menegazzi
AU  - Ying Yao
AU  - Hisanori Suzuki
AU  - Ulrich Förstermann
AU  - Hartmut Kleinert
TI  - Green Tea Inhibits Human Inducible Nitric-Oxide Synthase Expression by Down-Regulating Signal Transducer and Activator of Transcription-1α Activation
AID  - 10.1124/mol.65.1.111
DP  - 2004 Jan 01
TA  - Molecular Pharmacology
PG  - 111--120
VI  - 65
IP  - 1
4099  - http://molpharm.aspetjournals.org/content/65/1/111.short
4100  - http://molpharm.aspetjournals.org/content/65/1/111.full
SO  - Mol Pharmacol2004 Jan 01; 65
AB  - Green tea has been reported to show anti-inflammatory properties because of its inhibitory effects on the expression of several pro-inflammatory genes. Because the inducible nitricoxide synthase (iNOS) plays an important role in chronic inflammatory diseases, we have focused our attention on the regulation of iNOS expression by green tea in two different human epithelial cell lines, alveolar A549/8 and colon DLD-1 cells. With the use of electrophoretic mobility shift assays, we found a green tea-mediated down-regulation of the DNA binding activity of the transcription factor signal transducer and activator of transcription-1α (STAT-1α), but not of nuclear factor-κB. This down-regulation of the STAT-1α DNA binding was shown to result from reduced tyrosine phosphorylation of the STAT-1α protein and not from antioxidative effects of the green tea extract. Green tea extract inhibited human iNOS expression in a concentration-dependent manner, quantified in terms of iNOS mRNA, iNOS protein, and nitric oxide production in both cell lines. This inhibitory effect of green tea resulted from transcriptional inhibition as shown in reporter gene experiments. These data suggest that green tea extracts may be promising at least as an auxiliary anti-inflammatory principle in chronic inflammatory diseases.