Investigation of Oxtr-expressing Neurons Projecting to Nucleus Accumbens using Oxtr-Tres-Cre Knock-in prairie Voles (Microtus ochrogaster)

• Type of Material: Article
• Authors: Kengo Horie, Tohoku University; Kiyoshi Inoue, Emory University; Katsuhiko Nishimori, Tohoku University; Larry Young, Emory University
• Language: English
• Date: 2020-11-10
• Publisher: PERGAMON-ELSEVIER SCIENCE LTD
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2020 IBRO. Published by Elsevier Ltd. All rights reserved.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.neuroscience.2020.08.023
• Title of Journal or Parent Work: NEUROSCIENCE
• Volume: 448
• Start Page: 312
• End Page: 324
• Grant/Funding Information: The research performed in Japan was funded by the Strategic Research Program for Brain Sciences from Japan Agency for Medical Research and Development (AMED; 18dm0107076h0003, 2016–2020) and JSPS Grant-in-Aid for Scientific Research (15H02442, 2015–2018) to KN, and Grant-in-Aid for JSPS Fellows (16J05070, 2016–2019) to KH. The work performed at Emory in the USA was supported by NIH grants R01MH112788 and P50MH100023 to LJY and P51OD11132 to YNPRC.
• Keywords: DOPAMINE; nucleus accumbens; GENERATION; OXYTOCIN RECEPTOR; genome editing; MECHANISMS; social bonding; oxytocin receptor; BEHAVIOR; neural circuits; SEEKING; Science & Technology; FEMALE; CRISPR; Neurosciences; RNA; VASOPRESSIN; Neurosciences & Neurology; SOCIAL ATTACHMENT; Life Sciences & Biomedicine

Abstract

Social bonds such as parent–infant attachment or pair bonds can be critical for mental and physical well-being. The monogamous prairie vole (Microtus ochrogaster) has proven useful for examining the neural substrates regulating social behaviors, including social bonding. Oxytocin (OXT) and oxytocin receptor (OXTR) play critical roles in alloparental care, pair bonding and consoling behavior in prairie voles. While OXTR in a few regions, such as the nucleus accumbnes (NAcc), prefrontal cortex (PFC) and anterior cingulate cortex (ACC), have been implicated in regulating these behaviors, the extent to which other OXT sensitive areas modulate social behaviors has not been investigated. The NAcc is a central hub for modulating OXTR dependent social behaviors. To identify neurons expressing Oxtr in prairie vole brain, we generated gene knock-in voles expressing Cre recombinase in tandem with Oxtr (Oxtr-ires-Cre) using CRISPR/Cas9 genome editing. We confirmed Oxtr and Cre mRNA co-localization in NAcc, validating this model. Next, we identified putative Oxtr-expressing neurons projecting to NAcc by infusing retrograde CRE-dependent EGFP AAV into NAcc and visualizing fluorescence. We found enhanced green fluorescent protein (EGFP) positive neurons in anterior olfactory nucleus, PFC, ACC, insular cortex (IC), paraventricular thalamus (PVT), basolateral amygdala (BLA), and posteromedial and posterolateral cortical amygdaloid area (PMCo, PLCo). The ACC to NAcc OXTR projection may represent a species-specific circuit since Oxtr-expressing neurons in the ACC of mice were reported not to project to the NAcc. This is the first delineation of Oxtr-expressing neural circuits in the prairie vole, and demonstrates the utility of this novel genetically modified organism for characterizing OXTR circuits involved in social behaviors.