Effects of Porphyromonas gingivalis lipopolysaccharide on apoptotic genes in foam cells

Abstract

To investigate the effects of Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) on apoptotic genes in foam cells. Macrophages from THP-1 monocytes and foam cells from macrophages by oxLDL inducement were treated with oxidized low density lipoprotein (oxLDL) or oxLDL+ Pg-LPS. Cell apoptosis was detected by acridine orange-ethidium bromide (AO-EB) staining. Eleven atherosclerotic related apoptotic genes were examined with polymerase chain reaction (PCR) array, and apoptotic gene p53, c-Myc and caspase-3 were evaluated with real-time PCR. Pg-LPS enhanced cell apoptosis rate during and after foam cells formation [(5.47+/-0.93)% vs. (7.50+/-0.54)%]. PCR array demonstrated that it increased B-cell CLL-lymphoma 2 (BCL2) related protein A1 (BCL2A1) transcription during foam cells formation (>2 fold), and promoted BCL2 and BCL2A1 transcription after foam cells formation (>2 fold). It promoted p53 and caspase-3 transcription level (4.50x10(-3)+/-4.02x10(-4) vs. 5.30x10(-2)+/-4.58x10(-3)), whereas inhibited c-Myc transcription level (1.53x10(-2)+/-5.77x10(-4)) during foam cells formation. It promoted caspase-3 transcription (6.00x10(-2)+/-6.08x10(-3)), and inhibited p53 transcription (4.23x10(-3)+/-5.85x10(-4)) after foam cells formation. Pg-LPS affected apoptotic gene transcription during and after foam cells formation and enhanced cell apoptosis.