1
|
Molteni L, Rizzi L, Bresciani E, Possenti R, Petrocchi Passeri P, Ghè C, Muccioli G, Fehrentz JA, Verdié P, Martinez J, Omeljaniuk RJ, Biagini G, Binda A, Rivolta I, Locatelli V, Torsello A. Pharmacological and Biochemical Characterization of TLQP-21 Activation of a Binding Site on CHO Cells. Front Pharmacol 2017; 8:167. [PMID: 28424618 PMCID: PMC5371653 DOI: 10.3389/fphar.2017.00167] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/14/2017] [Indexed: 11/16/2022] Open
Abstract
VGF is a propeptide of 617 amino acids expressed throughout the central and the peripheral nervous system. VGF and peptides derived from its processing have been found in dense core vesicles and are released from neuronal and neuroendocrine cells via the regulated secretory pathway. Among VGF-derived neuropeptides, TLQP-21 (VGF556-576) has raised a huge interest and is one of most studied. TLQP-21 is a multifunctional neuropeptide involved in the control of several physiological functions, potentially including energy homeostasis, pain modulation, stress responsiveness and reproduction. Although little information is available about its receptor and the intracellular mechanisms mediating its biological effects, recent reports suggest that TLQP-21 may bind to the complement receptors C3aR1 and/or gC1qR. The first aim of this study was to ascertain the existence and nature of TLQP-21 binding sites in CHO cells. Secondly, we endeavored to characterize the ligand binding to these sites by using a small panel of VGF-derived peptides. And finally, we investigated the influence of TLQP-21 on selected intracellular signaling pathways. We report that CHO cells express a single class of saturable and specific binding sites for TLQP-21 with an affinity and capacity of Kd = 0.55 ± 0.05 × 10-9 M and Bmax = 81.7 ± 3.9 fmol/mg protein, respectively. Among the many bioactive products derived from the C-terminal region of VGF that we tested, TLQP-21 was the most potent in stimulating intracellular calcium mobilization in CHO cells; this effect is primarily due to its C-terminal fragment (HFHH-10). TLQP-21 induced rapid and transient dephosphorylation of phospholipase Cγ1 and phospholipase A2. Generation of IP3 and diacylglycerol was crucial for TLQP-21 bioactivity. In conclusion, our results suggest that the receptor stimulated by TLQP-21 belongs to the family of the Gq-coupled receptors, and its activation first increases membrane-lipid derived second messengers which thereby induce the mobilization of Ca2+ from the endoplasmic reticulum followed by a slower store-operated Ca2+ entry from outside the cell.
Collapse
Affiliation(s)
- Laura Molteni
- Department of Medicine and Surgery, University of Milano-BicoccaMonza, Italy.,PhD Program in Neuroscience, Department of Medicine and Surgery, University of Milano-BicoccaMonza, Italy
| | - Laura Rizzi
- Department of Medicine and Surgery, University of Milano-BicoccaMonza, Italy
| | - Elena Bresciani
- Department of Medicine and Surgery, University of Milano-BicoccaMonza, Italy
| | - Roberta Possenti
- Department of Medicine of Systems, University of Rome "Tor Vergata"Rome, Italy
| | | | - Corrado Ghè
- Department of Drug Science and Technology, University of TurinTurin, Italy
| | - Giampiero Muccioli
- Department of Drug Science and Technology, University of TurinTurin, Italy
| | - Jean-Alain Fehrentz
- Centre National de la Recherche Scientifique, Max Mousseron Institute of Biomolecules UMR5247, University of Montpellier, École Nationale Supérieure de Chimie de MontpellierMontpellier, France
| | - Pascal Verdié
- Centre National de la Recherche Scientifique, Max Mousseron Institute of Biomolecules UMR5247, University of Montpellier, École Nationale Supérieure de Chimie de MontpellierMontpellier, France
| | - Jean Martinez
- Centre National de la Recherche Scientifique, Max Mousseron Institute of Biomolecules UMR5247, University of Montpellier, École Nationale Supérieure de Chimie de MontpellierMontpellier, France
| | | | - Giuseppe Biagini
- Laboratory of Experimental Epileptology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio EmiliaModena, Italy
| | - Anna Binda
- Department of Medicine and Surgery, University of Milano-BicoccaMonza, Italy
| | - Ilaria Rivolta
- Department of Medicine and Surgery, University of Milano-BicoccaMonza, Italy
| | - Vittorio Locatelli
- Department of Medicine and Surgery, University of Milano-BicoccaMonza, Italy
| | - Antonio Torsello
- Department of Medicine and Surgery, University of Milano-BicoccaMonza, Italy
| |
Collapse
|