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2016-10-08 - Colloque/Présentation - poster - Anglais - 1 page(s)

Andre Séverine , Daldal Fatima, Delcroix Marie, Muller Robert , Vander Elst Luce , Laurent Sophie , Burtea Carmen , "New therapeutic management of Alzheimer’s disease: interest to a phospholipase A2-targeted peptide able to cross the blood-brain barrier through the LDL receptor" in Belgian Brain Congress, MICX. October 8, 2016., Mons, Belgique, 2016

  • Codes CREF : Sciences biomédicales (DI3200)
  • Unités de recherche UMONS : Chimie générale, organique et biomédicale (M108)
  • Instituts UMONS : Institut des Sciences et Technologies de la Santé (Santé), Institut des Biosciences (Biosciences)
  • Centres UMONS : Centre de Recherche en Microscopie et Imagerie Médicale (CMMI)

Abstract(s) :

(Anglais) L’objectif de ce projet est le développement d’une nouvelle stratégie thérapeutique de la maladie d’Alzheimer (MA) par modulation d’une molécule connue pour son implication dans les déficits de mémoire et la neurodégénérescence, appelée phospholipase A2. Un peptide spécifique à cette molécule a été identifié et sera couplé à un peptide facilitateur ciblant le récepteur aux LDL dans le but de passer la barrière hémato-encéphalique protégeant le cerveau. Cette nouvelle molécule pharmaceutique multifonctionnelle ainsi développée devra permettre une thérapie plus efficace de la MA. Introduction Alzheimer’s disease (AD) is one of the main causes of dementia in the elderly, being characterized by a progressive and irreversible loss of cognitive functions. Actual therapies are only symptomatic and the AD treatment is a real challenge. Indeed, AD is a multifactorial pathology triggered by hereditary (familial AD) and environmental (sporadic AD) factors, making its management especially challenging. Phospholipase A2 (PLA2) signaling pathway was recently revealed to be involved in this pathology [1] and the modulation of some isoforms was already attempted in the treatment of neurological disorders [2]. The goal of the present work is to target specifically a PLA2 isoform in order to develop a new therapeutic strategy for the AD patients, as an alternative of the existing molecules that are non-specific or irreversible. We have therefore identified a PLA2-targeted peptide (PL-P25) by phage display able to inhibit the PLA2 in preliminary in vitro tests. On the other hand, the blood-brain barrier (BBB), localized at the interface between the blood and the brain, protects the brain against xenobiotics and limits the access of most molecules, including potential therapeutic agents. The development of non-invasive BBB crossing strategies is thus crucial to accede to the central nervous system (CNS) without BBB disruption. LDL receptor (LDLR) seems to be an interesting target for drug delivery due to its involvement in LDL transcytosis [3]. A LDLR-targeted peptide (LR-P2) was identified in order to facilitate the access to the brain of our therapeutic peptide. Methods A randomized linear peptide library fused to the p3 coat proteins of the M13 bacteriophage was used to identify PLA2- and LDLR-specific peptides. Peptide specificity was evaluated by immunofluorescence on mouse brain slices or human brain endothelial cells (ACBRI376) by colocalization with their respective target. The inhibitory effect of PL-P25 (alone or multivalent by coupling to streptavidin), targeted to PLA2, was evaluated by the dosage of AA release from H2O2-induced human astrocytes (1321N1) and from glutamate-induced mouse neurons (N18TG2). The mechanism of transcytosis of LR-P2, targeting LDLR, was investigated by immunofluorescence allowing to observe its colocalization with caveolae or lysosomes. After LR-P2 coupling to iron oxide nanoparticles (USPIO-LRP2), its crossing over the BBB was evaluated after in vivo injection of NMRI mice by nuclear magnetic resonance (NMR) relaxometry and Perls’-DAB histochemistry staining. Results and Prospects The PLA2-targeted peptide PL-P25, selected for its affinity among two others, showed a good colocalization with the target on mouse brain slices, confirming its specificity. Its inhibitory potential on the PLA2 activity was confirmed on 1321N1 and N18TG2 cells, with an effect that ranged from 20% to 60% compared to positive control (induced but non inhibited cells), and a more potent activity at low concentrations (20µM) and for the multivalent model. Concerning the BBB crossing strategy, LR-P2 has co-localized with LDLR expressed by human brain endothelial cells, while its endocytosis via a caveolae-mediated non-degradation pathway was confirmed on these cells. After in vivo administration, USPIO-LRP2 was found within the brain parenchyma of NMRI mice, around the 3rd ventricle and brain capillaries by iron staining. NMR relaxometry has also confirmed the presence of USPIO-LRP2 in the brain, whereas the control nanoparticles coupled to a non-specific peptide (USPIO-NSP) was not able to cross the BBB as proven by both methods. This peptide will be used as vector in order to facilitate the access to the brain of our therapeutic peptide described above. References 1. Schaeffer EL et al. Prog Neuropsychopharmacol Biol Psychiatry. 2010;34: 1381–1389. 2. Kudo I, Murakami M. Prostaglandins Other Lipid Mediat. 2002;68-69: 3–58. 3. Dehouck B et al. J Cell Biol. 1997;138: 877–889.

Identifiants :
  • DOI : 10.3389/conf.fnagi.2016.03.00046