title: JMV5656, A Novel Derivative of TLQP-21, Triggers the Activation of a Calcium-Dependent Potassium Outward Current in Microglial Cells.
abstract: TLQP-21 (TLQPPASSRRRHFHHALPPAR) is a multifunctional peptide that is involved in the control of physiological functions, including feeding, reproduction, stress responsiveness, and general homeostasis. Despite the huge interest in TLQP-21 biological activity, very little is known about its intracellular mechanisms of action. In microglial cells, TLQP-21 stimulates increases of intracellular Ca2+that may activate functions, including proliferation, migration, phagocytosis and production of inflammatory molecules. Our aim was to investigate whether JMV5656 (RRRHFHHALPPAR), a novel short analogue of TLQP-21, stimulates intracellular Ca2+in the N9 microglia cells, and whether this Ca2+elevation is coupled with the activation Ca2+-sensitive K+channels. TLQP-21 and JMV5656 induced a sharp, dose-dependent increment in intracellular calcium. In 77% of cells, JMV5656 also caused an increase in the total outward currents, which was blunted by TEA (tetraethyl ammonium chloride), a non-selective blocker of voltage-dependent and Ca2+-activated potassium (K+) channels. Moreover, the effects of ion channel blockers charybdotoxin and iberiotoxin, suggested that multiple calcium-activated K+channel types drove the outward current stimulated by JMV5656. Additionally, inhibition of JMV5656-stimulated outward currents by NS6180 (4-[[3-(trifluoromethyl)phenyl]methyl]-2H-1,4 benzothiazin-3(4H)-one) and TRAM-34 (triarylmethane-34), indicated that KCa3.1 channels are involved in this JMV5656 mechanisms of action. In summary, we demonstrate that, in N9 microglia cells, the interaction of JMV5656 with the TLQP-21 receptors induced an increase in intracellular Ca2+, and, following extracellular Ca2+entry, the opening of KCa3.1 channels.
authors.affiliation: Department of Medicine and Surgery, University of Milano-Bicocca Monza, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Rivolta
authors.affiliation: Department of Medicine and Surgery, University of Milano-Bicocca Monza, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Binda
authors.affiliation: Department of Medicine and Surgery, University of Milano-Bicocca Monza, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Molteni
authors.affiliation: Department of Medicine and Surgery, University of Milano-Bicocca Monza, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Rizzi
authors.affiliation: Department of Medicine and Surgery, University of Milano-Bicocca Monza, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Bresciani
authors.affiliation: Department of Medicine of Systems, University of Rome "Tor Vergata" Rome, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Possenti
authors.affiliation: CNRS, Institut des Biomolécules Max Mousseron UMR5247, École Nationale Supérieure de Chimie de Montpellier - University of Montpellier Montpellier, France.
authors.forename: Jean-Alain
authors.initials: JA
authors.lastname: Fehrentz
authors.affiliation: CNRS, Institut des Biomolécules Max Mousseron UMR5247, École Nationale Supérieure de Chimie de Montpellier - University of Montpellier Montpellier, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Verdié
authors.affiliation: CNRS, Institut des Biomolécules Max Mousseron UMR5247, École Nationale Supérieure de Chimie de Montpellier - University of Montpellier Montpellier, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Martinez
authors.affiliation: Department of Biology, Lakehead University, Thunder Bay ON, Canada.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Omeljaniuk
authors.affiliation: Department of Medicine and Surgery, University of Milano-Bicocca Monza, Italy.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Locatelli
authors.affiliation: Department of Medicine and Surgery, University of Milano-Bicocca Monza, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Torsello
keywords: Ca2+-activated K+ channels; K+ current; TLQP-21; microglia; patch clamp