An important tenet of learning and memory is the notion of a molecular switch that promotes the formation of long-term memory1–4. The regulation of proteostasis is a critical and rate-limiting step in the consolidation of new memories5–10. One of the most effective and prevalent ways to enhance memory is by regulating the synthesis of proteins controlled by the translation initiation factor eIF211. Phosphorylation of the α-subunit of eIF2 (p-eIF2α), the central component of the integrated stress response (ISR), impairs long-term memory formation in rodents and birds11–13. By contrast, inhibiting the ISR by mutating the eIF2α phosphorylation site, genetically11 and pharmacologically inhibiting the ISR kinases14–17, or mimicking reduced p-eIF2α with the ISR inhibitor ISRIB11, enhances long-term memory in health and disease18. Here we used molecular genetics to dissect the neuronal circuits by which the ISR gates cognitive processing. We found that learning reduces eIF2α phosphorylation in hippocampal excitatory neurons and a subset of hippocampal inhibitory neurons (those that express somatostatin, but not parvalbumin). Moreover, ablation of p-eIF2α in either excitatory or somatostatin-expressing (but not parvalbumin-expressing) inhibitory neurons increased general mRNA translation, bolstered synaptic plasticity and enhanced long-term memory. Thus, eIF2α-dependent mRNA translation controls memory consolidation via autonomous mechanisms in excitatory and somatostatin-expressing inhibitory neurons.
|Number of pages||5|
|State||Published - 15 Oct 2020|
Bibliographical noteFunding Information:
Acknowledgements This study was supported by a Canada’s International Development Research Centre (IDRC), in partnership with the Azrieli Foundation, the Canadian Institutes of Health Research (CIHR), and the Israel Science Foundation (ISF) to K.R. and N.S. J.-C.L. is supported by a CIHR Project grant (PJT-153311) and a Canada Research Chair in Cellular and Molecular Neurophysiology (CRC-950-231066). R.J.K. is supported by National Institutes of Health (NIH) Project grants (R01 DK113171, R01 DK103185, R01 CA198103 and R01 AG062190). E.S. is supported by the Ministerio de Ciencia, Innovación y Universidades (RTI2018-101838-J-I00) and A.Q. is supported by the European Research Council (ERC-2014-StG-638106), Ministerio de Economía y Competitividad (SAF2017-88108-R) and Agència de Gestió d’Ajuts Universitaris i de Recerca (2017SGR-323). M.C.-M. is supported by the National Institute of Neurological Disorders and Stroke grant (2R01 NS076708-06 NINDS). Support to R.S. was provided by Richard and Edith Strauss Postdoctoral Fellowships in Medicine. We thank the CNAG-CRG for assistance with RNA sequencing; G. S. McKnight for the RPL22-HA plasmid; members of the Sonenberg laboratory, specifically I. Harvey, A. Lafrance, A. Sylvestre, E. Migon and S. Murthy, as well as I. Laplante, H. Hall, M. Anadolu and K. Gamache for support with animals and resources; and S. Tahmasebi for critical reading of the manuscript.
© 2020, The Author(s), under exclusive licence to Springer Nature Limited.
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