title: Proteomic exploitation on prothymosin alpha-induced mononuclear cell activation.
abstract: Prothymosin alpha (ProTalpha) is an acidic polypeptide associated both with cell proliferation and immune regulation. Although ProTalpha's immunomodulating activity is well established at cellular level, limited information is available regarding the signaling pathways triggered by ProTalpha. Using 2-DE proteomic technology, we investigated changes in protein expression of ProTalpha-stimulated peripheral blood mononuclear cells (PBMC) in the course of a 3-day incubation. Using healthy donor- and cancer patient-derived PBMC, 12 gels were studied, identifying 53 differing protein spots via PMF comparison analysis. Among others, we identified interleukin-1 receptor-associated kinase 4, heat-shock protein 90, lipocalin 2, ribophorin 1, eukaryotic elongation factor 2, 14-3-3 protein, L-plastin, and MX2 protein, all of which were found to be overexpressed upon ProTalpha activation. Based on the physiological role of upregulated proteins, we propose the following model for ProTalpha's immunological mode of action: on day 1, ProTalpha triggers monocyte activation, possibly via toll-like receptor signaling, and enhances antigen presentation, consequently promoting and stabilizing monocyte-T-cell immune synapse; on day 2, activated monocytes produce interleukin (IL)-1, while T-cell receptor triggering promotes T-cell proliferation and IL-2 production; finally, on day 3, ProTalpha-activated PBMC express proteins related to adhesion and cytotoxic effector functions, both contributing to the increase of their lytic activity.
authors.affiliation: Department of Animal and Human Physiology, Faculty of Biology, University of Athens, Athens, Greece. mskopelit@biol.uoa.gr
authors.forename: Margarita
authors.initials: M
authors.lastname: Skopeliti
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kratzer
authors.forename: Florian
authors.initials: F
authors.lastname: Altenberend
authors.forename: George
authors.initials: G
authors.lastname: Panayotou
authors.forename: Hubert
authors.initials: H
authors.lastname: Kalbacher
authors.forename: Stefan
authors.initials: S
authors.lastname: Stevanovic
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Voelter
authors.forename: Ourania E
authors.initials: OE
authors.lastname: Tsitsilonis
mesh_terms: D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology*; D010051:Ovarian Neoplasms / Q000097:blood / Q000276:immunology*; D011498:Protein Precursors / Q000494:pharmacology / Q000502:physiology*; D011506:Proteins / Q000032:analysis* / Q000378:metabolism; D040901:Proteomics; D012016:Reference Values; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013947:Thymosin / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000502:physiology
chemical_list: D011498:Protein Precursors; D011506:Proteins; C040782:prothymosin alpha; D013947:Thymosin