title: Enteropathogenic Escherichia coli outer membrane proteins induce iNOS by activation of NF-kappaB and MAP kinases.
abstract: Enteropathogenic Escherichia coli (EPEC) infects the human intestinal epithelium and is a major cause of infantile diarrhea in developing countries. Nitric oxide (NO) is an important modulator of intestinal inflammatory response. The aim of the present study was to investigate whether EPEC outer membrane proteins (OMPs) up regulate epithelial cell expression of inducible nitric oxide synthase (iNOS) and to examine the role of NF-kappaB and MAP kinases (MAPK) on nitrite production. iNOS mRNA expression was assessed by RT-PCR. Nitrite levels were measured by Griess reaction. NF-kappaB activation by OMPs was evaluated by EMSA and immunoblotting was done to detect MAPK activation. EPEC OMP up regulated iNOS, induced nitrite production and NF-kappaB and MAPK were activated in caco-2 cells. The nitrite levels decreased when NF-kappaB and MAPK inhibitors were used. Thus, EPEC OMPs induce iNOS expression and NO production through activation of NF-kappaB and MAPK.
authors.affiliation: Centre for Biotechnology, Anna University, Chennai 600 025, India.
authors.forename: Vasantha
authors.initials: V
authors.lastname: Malladi
authors.forename: Manjula
authors.initials: M
authors.lastname: Puthenedam
authors.forename: Peter H
authors.initials: PH
authors.lastname: Williams
authors.forename: Arun
authors.initials: A
authors.lastname: Balakrishnan
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism*; D018938:Caco-2 Cells; D024202:Electrophoretic Mobility Shift Assay; D004789:Enzyme Activation / Q000187:drug effects; D004790:Enzyme Induction; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004926:Escherichia coli / Q000235:genetics / Q000472:pathogenicity*; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D008163:Luminescent Measurements; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics; D009570:Nitriles / Q000494:pharmacology; D009573:Nitrites / Q000032:analysis / Q000037:antagonists & inhibitors; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013450:Sulfones / Q000494:pharmacology
chemical_list: C434003:3-(4-methylphenylsulfonyl)-2-propenenitrile; D001425:Bacterial Outer Membrane Proteins; D004791:Enzyme Inhibitors; D005419:Flavonoids; D007093:Imidazoles; D016328:NF-kappa B; D009570:Nitriles; D009573:Nitrites; D011725:Pyridines; D012333:RNA, Messenger; D013450:Sulfones; D019001:Nitric Oxide Synthase; D020928:Mitogen-Activated Protein Kinases; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D019331:NG-Nitroarginine Methyl Ester