NR ADKQ
AU Diomede,L.; Sozzani,S.; Luini,W.; Algeri,M.; de Gioia,L.; Chiesa,R.; Lievens,P.M.J.; Bugiani,O.; Forloni,G.; Tagliavini,F.; Salmona,M.
TI Activation effects of a prion protein fragment [PrP-(106-126)] on human leucocytes
QU Biochemical Journal 1996 Dec 1; 320(2): 563-70
PT journal article
AB Prion-related encephalopathies are characterized by the intracerebral accumulation of an abnormal isoform of the cellular prion protein (PrPc) named scrapie prion protein (PrPsc). The pathological forms of this protein and its cellular precursor are not only expressed in the brain but also, at lower concentrations, in peripheral tissues. We recently showed that a synthetic peptide corresponding to residues 106-126 [PrP-(106-126)] of the human PrP is toxic to neurons and trophic to astrocytes in vitro. Our experiments were aimed at verifying whether PrP-(106-126) and other peptides corresponding to fragments of the amyloid protein purified from brains of patients with Gerstmann-Sträussler-Scheinker disease-namely PrP-(89-106), PrP-(106-114), PrP-(127-147)-were capable of stimulating circulating leucocytes. Native PrP expression in human lymphocytes, monocytes and neutrophils was first confirmed using PCR amplification of total RNA, after reverse transcription, and immunoblot analysis of cell extracts with anti-PrP antibodies. PrP-(106-126), but not the other peptides, increased membrane microviscosity, intracellular Ca2+ concentration and cell migration in circulating leucocytes, and O2-. production in monocytes and neutrophils. Membrane microviscosity was determined by the fluorescence polarization technique, using diphenylhexatriene as a probe, 300 s after the addition of PrP-(106-126) to the cell suspension in the concentration range 5-50 microM. The increase in intracellular Ca2+ elicited by PrP-(106-126) was dose-dependent in the range 5-500 microM. PrP-(106-126) stimulated O2-. production in monocytes and neutrophils in a dose- (10-300 microM) and time-(5-30 min) dependent manner in the presence of 10 microM dihydrocytochalasin B. Both the increase in Ca2+ concentration and the O2-. production were partially sensitive to pertussis toxin. PrP-(106-126) stimulated leucocyte migration in a dose-dependent (30-300 microM) manner and, at the highest concentration used, this migration was comparable with that elicited by 2.5 nM interleukin 8 or 10 nM fMet-Leu-Phe peptide.
IN Durch PCR-Amplifikation von RNA sowie durch Immunoblots wurde festgestellt, dass menschliche Lymphozyten, Monozyten und Neutrophile das normale Prionprotein exprimieren. Das Prionproteinfragment PrP-(106-126) steigert die Membranmikroviskosität und die intrazelluläre Calciumionenkonzentration in zirkulierenden Leukozyten und erhöht die Konzentration von (O2-)-Ionen in , Monozyten und Neutrophilen, während die ebenfalls in Gerstmann-Sträussler-Scheinker-Patienten gefundenen Prionproteinfragmente PrP-(89-106), PrP-(106-114) oder PrP(127-147) unwirksam sind. Die Membranmikroviskosität nahm 5 Min. nach Zugabe von PrP-(106-126) auf Konzentrationen von 5-50 µM zu. Die Zunahme der intrazellulären Calciumionenkonzentration erfolgte dosisabhängig bei Konzentrationen von 5-500 µM. Die Produktion der (O2-)-Ionen erfolgte dosis- (10-300 µM) und zeitabhängig (5-30 Min.) in Anwesenheit von 10 µM Dihydrocytochalasin B. Die Zunahme der Calciumionenkonzentration und die Produktion der (O2-)-Ionen wurden durch Pertussis Toxin reduziert. Das PrP-(106-126) steigerte außerdem bei Konzentrationen von 30-300 µM dosisabhängig die Leukozytenmigration. Bei der höchsten Konzentration entsprach die Wirkung 2,5 nM Interleukin 8 oder 10 nM fMet-Leu-Phe Peptid.
ZR 36
MH Actins/*biosynthesis; Amino Acid Sequence; Calcium/blood; Cell Membrane/drug effects/physiology; Chemotaxis, Leukocyte/*drug effects; Comparative Study; DNA Primers; Human; Kinetics; Leukocytes/drug effects/*physiology; Lymphocytes/physiology; Molecular Sequence Data; Monocytes/physiology; Neutrophils/physiology; Peptide Fragments/*pharmacology; Polymerase Chain Reaction; Prions/*biosynthesis/blood/*pharmacology; Superoxides/blood; Support, Non-U.S. Gov't; Transcription, Genetic/*drug effects
AD Istituto di Ricerche Farmacologiche Mario Negri.
SP englisch
PO England