Venue: Centre Broca Nouvelle-Aquitaine
Marilena Griguoli
– Institute of Molecular Biology and Pathology of the National Research Council (CNR), Rome
– European Brain Research Institute (EBRI), Rome
Invited by Christophe Mulle
Title
Role of septal cholinergic neurons in social novelty discrimination
Abstract
In spite of its well-established neuromodulatory effect on attention, memory and learning, the role of acetylcholine (ACh) in social memory, meaning the ability of an animal to discriminate between a stranger and a familiar one is less known. Medial Septum/Diagonal Band of Broca (MSDB) nuclei contain cholinergic neurons projecting to different brain areas including the hippocampal CA2 region, involved in social memory encoding. Here, different strategies have been used to control the activity of cholinergic neurons in the MSDB to evaluate its effect on social memory and on CA2 circuit functionality. Our results point to nicotinic ACh receptors as essential players in social memory by controlling inhibition in the CA2 region. Alterations in ChAT neurons have been observed in Autism Spectrum Disorders (ASD), neurodevelopmental conditions characterized by social isolation, stereotyped movements and communication challenges. Some forms of ASD are associated with mutations in genes encoding for synaptic proteins including the neuroligin 3 (NLG3), a postsynaptic adhesion molecule that binds its presynaptic partner neurexin and stabilizes both excitatory and inhibitory synapses. Mice lacking NLG3 (NLG3-/y) show deficits in social interaction and social memory similar to those observed in autistic patients. Here, we propose to study whether cholinergic dysfunction accounts for social memory deficits observed in NLG3-/y mice. Conditional suppression of Nlg3 expression in MSDB ChAT neurons induced an impairment in both social memory and synaptic function similarly to what observed in NLG3-/y mice. The rescue of Nlg3 expression in MSDB ChAT neurons of NLG3-/y mice will corroborate the evidence that a cholinergic dysfunction may cause social memory deficits in ASD.
Key pubblications
Pizzarelli R, Pimpinella P, Jacobs C, Tartacca A, Kullolli U, Monyer H, Alberini C M, Griguoli M (2023). Insulin-like growth factor 2 (IGF-2) rescues social deficits in NLG3-/y mouse model of ASDs. Front Cell Neurosci, 17:1332179.
Pimpinella D, Mastrorilli V, Giorgi C, Coemans S, Lecca S, Lalive AL, Ostermann H, Fuchs EC, Monyer H, Mele A, Cherubini E, Griguoli M (2021). Septal cholinergic input to CA2 hippocampal region controls social novelty discrimination via nicotinic receptor-mediated disinhibition. ELife 10:e65580
Modi B, Pimpinella D, Pazienti A, Zacchi P, Cherubini E, Griguoli M (2019). Possible implication of the CA2 hippocampal circuit in social cognition deficits observed in the neuroligin 3 knock-out mouse, a non-syndromic animal model of Autism. Front Psychiatry 10: 513.