title: Immunoproteomic identification and characterization of Ni2+-regulated proteins implicates Ni2+in the induction of monocyte cell death.
abstract: Nickel allergy is the most common cause of allergic reactions worldwide, with cutaneous and systemic effects potentially affecting multiple organs. Monocytes are precursors of not only macrophages but also dendritic cells, the most potent activators of nickel hypersensitivity. Monocytes are themselves important antigen-presenting cells, capable of nickel-specific T-cell activation in vivo and in vitro, in addition to being important for immediate innate immune inflammation. To elucidate early Ni2+-dependent inflammatory molecular mechanisms in human monocytes, a Ni2+-specific proteomic approach was applied. Quantitative two-dimensional (2D) differential gel electrophoresis and Delta2D software analyses coupled with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) revealed that Ni2+significantly regulated 56 protein species, of which 36 were analyzed by MALDI-MS. Bioinformatics analyses of all identified proteins resulted in Ni2+-associated functional annotation clusters, such as cell death, metal ion binding, and cytoskeletal remodeling. The involvement of Ni2+in the induction of monocyte cell death, but not T-cell death, was observed at Ni2+concentrations at or above 250 μM. Examination of caspase activity during Ni2+-mediated cell death revealed monocytic cell death independent of caspase-3 and -7 activity. However, confocal microscopy analysis demonstrated Ni2+-triggered cytoskeletal remodeling and nuclear condensation, characteristic of cellular apoptosis. Thus, Ni2+-specific peripheral blood mononuclear cell stimulation suggests monocytic cell death at Ni2+concentrations at or above 250 μM, and monocytic effects on immune regulation at lower Ni2+concentrations.
authors.affiliation: Laboratory for Immunology and Proteomics, Department of Dermatology and University Medical Center Mannheim, University of Heidelberg, Mannheim 68167, Germany.
authors.forename: Annika
authors.initials: A
authors.lastname: Jakob
authors.affiliation: German Federal Institute for Risk Assessment, Chemicals and Product Safety, Berlin 10589, Germany.
authors.forename: Franz
authors.initials: F
authors.lastname: Mussotter
authors.affiliation: Laboratory for Immunology and Proteomics, Department of Dermatology and University Medical Center Mannheim, University of Heidelberg, Mannheim 68167, Germany.|Department of Molecular Immunology, Biology III, University of Freiburg and Max-Planck-Institute for Immunobiology and Epigenetics, Freiburg 79108, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Ohnesorge
authors.affiliation: Laboratory for Immunology and Proteomics, Department of Dermatology and University Medical Center Mannheim, University of Heidelberg, Mannheim 68167, Germany.|Functional Proteome Analysis, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany.
authors.forename: Lisa
authors.initials: L
authors.lastname: Dietz
authors.affiliation: Aragón I+D Foundation (ARAID), Zaragoza, Spain.|Department of Microbiology, Preventive Medicine and Public Health, University of Zaragoza/IIS Aragón, Zaragoza, Spain.|Biomedical Research Center of Aragón (CIBA), Aragón Health Research Institute (IIS Aragón), University of Zaragoza, Zaragoza, Spain.|Nanoscience Institute of Aragon (INA), University of Zaragoza, Zaragoza, Spain.
authors.forename: Julian
authors.initials: J
authors.lastname: Pardo
authors.affiliation: Dalhousie Inflammation Group, Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada.
authors.forename: Ian D
authors.initials: ID
authors.lastname: Haidl
authors.affiliation: Laboratory for Immunology and Proteomics, Department of Dermatology and University Medical Center Mannheim, University of Heidelberg, Mannheim 68167, Germany.|German Federal Institute for Risk Assessment, Chemicals and Product Safety, Berlin 10589, Germany.|Functional Proteome Analysis, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany.
authors.forename: Hermann-Josef
authors.initials: HJ
authors.lastname: Thierse
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects*; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000378:metabolism; D009000:Monocytes / Q000187:drug effects* / Q000378:metabolism; D009532:Nickel / Q000494:pharmacology*; D020543:Proteome / Q000378:metabolism*; D040901:Proteomics / Q000379:methods; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism
chemical_list: D020543:Proteome; D009532:Nickel; D053148:Caspase 3; D053179:Caspase 7