title: T cell receptor-stimulated generation of hydrogen peroxide inhibits MEK-ERK activation and lck serine phosphorylation.
abstract: Previous studies indicated that antigen receptor (TcR) stimulation of mature T cells induced rapid generation of reactive oxygen species (ROS). The goal of the current study was to examine the role(s) of ROS in TcR signal transduction, with a focus upon the redox-sensitive MAPK family. TcR cross-linking of primary human T blasts and Jurkat human T cells rapidly activated the ERK, JNK, p38 and Akt kinases within minutes, and was temporally associated with TcR-stimulated production of hydrogen peroxide (H(2)O(2)). TcR-induced activation of ERK was selectively augmented and sustained in the presence of pharmacologic antioxidants that can quench or inhibit H(2)O(2) production (NAC, MnTBAP and Ebselen, but not DPI), while activation of JNK and Akt were largely unaffected. This was paralleled by concurrent changes in MEK1/2 phosphorylation, suggesting that ROS acted upstream of MEK-ERK activation. Molecular targeting of H(2)O(2) by overexpression of peroxiredoxin II, a thioredoxin dependent peroxidase, also increased and sustained ERK and MEK activation upon TcR cross-linking. Enhancement of ERK phosphorylation by antioxidants correlated with increased and sustained serine phosphorylation of the src-family kinase lck, a known ERK substrate. Thus, the data suggest that TcR-stimulated production of hydrogen peroxide negatively feeds back to dampen antigen-stimulated ERK activation and this redox-dependent regulation may serve to modulate key steps in TcR signaling.
authors.affiliation: Immunology Department, Jerome H. Holland Laboratory for the Biomedical Sciences, American Red Cross, Rockville, MD, USA.
authors.forename: J
authors.initials: J
authors.lastname: Kwon
authors.forename: S
authors.initials: S
authors.lastname: Devadas
authors.forename: M S
authors.initials: MS
authors.lastname: Williams
mesh_terms: D000975:Antioxidants / Q000378:metabolism / Q000494:pharmacology; D001393:Azoles / Q000378:metabolism; D017252:CD3 Complex / Q000096:biosynthesis; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004789:Enzyme Activation; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D015151:Immunoblotting; D054833:Isoindoles; D048031:JNK Mitogen-Activated Protein Kinases; D019169:Jurkat Cells; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / Q000378:metabolism*; D048670:MAP Kinase Kinase 4; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016566:Organoselenium Compounds / Q000378:metabolism; D010084:Oxidation-Reduction; D010544:Peroxidases / Q000378:metabolism; D054464:Peroxiredoxins; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D017382:Reactive Oxygen Species; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D012694:Serine / Q000378:metabolism*; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000378:metabolism; D013879:Thioredoxins / Q000378:metabolism; D013997:Time Factors; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D000975:Antioxidants; D001393:Azoles; D017252:CD3 Complex; D003432:Cross-Linking Reagents; D054833:Isoindoles; D016566:Organoselenium Compounds; D011518:Proto-Oncogene Proteins; D017382:Reactive Oxygen Species; D011948:Receptors, Antigen, T-Cell; C042986:ebselen; D012694:Serine; D013879:Thioredoxins; D006861:Hydrogen Peroxide; D010544:Peroxidases; D054464:Peroxiredoxins; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases