Interleukin-17 affects synaptic plasticity and cognition in an experimental model of multiple sclerosis
Massimiliano Di Filippo, Andrea Mancini, Laura Bellingacci, Lorenzo Gaetani, Petra Mazzocchetti, Teresa Zelante, Livia La Barbera, Antonella De Luca, Michela Tantucci, Alessandro Tozzi, Valentina Durante, Miriam Sciaccaluga, Alfredo Megaro, Davide Chiasserini, Nicola Salvadori, Viviana Lisetti, Emilio Portaccio, Cinzia Costa, Paola Sarchielli, Maria Pia Amato, Lucilla Parnetti, Maria Teresa Viscomi, Luigina Romani, Paolo Calabresi
Abstract
Cognitive impairment (CI) is a disabling concomitant of multiple sclerosis (MS) with a complex and controversial pathogenesis. The cytokine interleukin-17A (IL-17A) is involved in the immune pathogenesis of MS, but its possible effects on synaptic function and cognition are still largely unexplored. In this study, we show that the IL-17A receptor (IL-17RA) is highly expressed by hippocampal neurons in the CA1 area and that exposure to IL-17A dose-dependently disrupts hippocampal long-term potentiation (LTP) through the activation of its receptor and p38 mitogen-activated protein kinase (MAPK). During experimental autoimmune encephalomyelitis (EAE), IL-17A overexpression is paralleled by hippocampal LTP dysfunction. An in vivo behavioral analysis shows that visuo-spatial learning abilities are preserved when EAE is induced in mice lacking IL-17A. Overall, this study suggests a key role for the IL-17 axis in the neuro-immune cross-talk occurring in the hippocampal CA1 area and its potential involvement in synaptic dysfunction and MS-related CI.