Rescue of impaired sociability and anxiety-like behavior in adult cacna1c-deficient mice by pharmacologically targeting eIF2[alpha]

• Published in: Molecular psychiatry Vol. 22; no. 8; p. 1096
• Main Authors: Kabir, Z D, Che, A, Fischer, D K, Rice, R C, Rizzo, B K, Byrne, M, Glass, M J, De Marco Garcia, N V, Rajadhyaksha, A M
• Format: Journal Article
• Language: English
• Published: New York Nature Publishing Group 01-08-2017
• Subjects: Anxiety; Brain; Calcium; Calcium channels; Calcium channels (L-type); Caveolin-1; Cognitive ability; Cortex; Disease susceptibility; Forebrain; Genetic aspects; Glutamatergic transmission; Information processing; Initiation factors; Learning; Memory; Mental disorders; Mice; mRNA; Nervous system diseases; Neurons; Phosphorylation; Physiological aspects; Protein biosynthesis; Protein synthesis; Pyramidal cells; Risk factors; Rodents; Single nucleotide polymorphisms; Single-nucleotide polymorphism; Social behavior; United States
• ISSN: 1359-4184; 1476-5578
• DOI: 10.1038/mp.2017.124

CACNA1C, encoding the Ca[sub.v]1.2 subunit of L-type Ca[sup.2+] channels, has emerged as one of the most prominent and highly replicable susceptibility genes for several neuropsychiatric disorders. Ca[sub.v]1.2 channels play a crucial role in calcium-mediated processes involved in brain development and neuronal function. Within the CACNA1C gene, disease-associated single-nucleotide polymorphisms have been associated with impaired social and cognitive processing and altered prefrontal cortical (PFC) structure and activity. These findings suggest that aberrant Ca[sub.v]1.2 signaling may contribute to neuropsychiatric-related disease symptoms via impaired PFC function. Here, we show that mice harboring loss of cacna1c in excitatory glutamatergic neurons of the forebrain (fbKO) that we have previously reported to exhibit anxiety-like behavior, displayed a social behavioral deficit and impaired learning and memory. Furthermore, focal knockdown of cacna1c in the adult PFC recapitulated the social deficit and elevated anxiety-like behavior, but not the deficits in learning and memory. Electrophysiological and molecular studies in the PFC of cacna1c fbKO mice revealed higher E/I ratio in layer 5 pyramidal neurons and lower general protein synthesis. This was concurrent with reduced activity of mTORC1 and its downstream mRNA translation initiation factors eIF4B and 4EBP1, as well as elevated phosphorylation of eIF2[alpha], an inhibitor of mRNA translation. Remarkably, systemic treatment with ISRIB, a small molecule inhibitor that suppresses the effects of phosphorylated eIF2[alpha] on mRNA translation, was sufficient to reverse the social deficit and elevated anxiety-like behavior in adult cacna1c fbKO mice. ISRIB additionally normalized the lower protein synthesis and higher E/I ratio in the PFC. Thus this study identifies a novel Ca[sub.v]1.2 mechanism in neuropsychiatric-related endophenotypes and a potential future therapeutic target to explore. Molecular Psychiatry (2017) 22, 1096-1109; doi: 10.1038/mp.2017.124; published online 6 June 2017