Genetic targeting of adult Renshaw cells using a Calbindin 1 destabilized Cre allele for intersection with Parvalbumin or Engrailed1

• Type of Material: Article
• Authors: Alicia R Lane, Emory University; Indeara C Cogdell, Emory University; Thomas M Jessell, Columbia University; Jay B Bikoff, St. Jude Children’s Research Hospital; Francisco Alvarez, Emory University
• Language: English
• Date: 2021-10-06
• Publisher: NATURE PORTFOLIO
• Publication Version: Final Published Version
• Copyright Statement: © The Author(s) 2021
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1038/s41598-021-99333-6
• Title of Journal or Parent Work: SCIENTIFIC REPORTS
• Volume: 11
• Issue: 1
• Start Page: 19861
• End Page: 19861
• Grant/Funding Information: This work was supported by NIH-NINDS grants R01NS047357 and R21 NS106209 (FJA) and R01NS123116 (JBB), and the American Lebanese Syrian Associated Charities (JBB).; This research project was also supported by the Viral Vector Core of the Emory, funded in part supported by the Emory Neuroscience NINDS Core Facilities grant P30NS055077
• Keywords: DOPAMINERGIC-NEURONS; EXPRESSION; Multidisciplinary Sciences; RECURRENT INHIBITION; SPINAL-CORD; FLP; Science & Technology - Other Topics; Science & Technology; RECOMBINASE; SYSTEM; MICE; INTERNEURONS; RECEPTOR CLUSTERS
• Research Categories: Chemistry, Biochemistry

Abstract

Renshaw cells (RCs) are one of the most studied spinal interneurons; however, their roles in motor control remain enigmatic in part due to the lack of experimental models to interfere with RC function, specifically in adults. To overcome this limitation, we leveraged the distinct temporal regulation of Calbindin (Calb1) expression in RCs to create genetic models for timed RC manipulation. We used a Calb1 allele expressing a destabilized Cre (dgCre) theoretically active only upon trimethoprim (TMP) administration. TMP timing and dose influenced RC targeting efficiency, which was highest within the first three postnatal weeks, but specificity was low with many other spinal neurons also targeted. In addition, dgCre showed TMP-independent activity resulting in spontaneous recombination events that accumulated with age. Combining Calb1-dgCre with Parvalbumin (Pvalb) or Engrailed1 (En1) Flpo alleles in dual conditional systems increased cellular and timing specificity. Under optimal conditions, Calb1-dgCre/Pvalb-Flpo mice targeted 90% of RCs and few dorsal horn neurons; Calb1-dgCre/En1-Flpo mice showed higher specificity, but only a maximum of 70% of RCs targeted. Both models targeted neurons throughout the brain. Restricted spinal expression was obtained by injecting intraspinally AAVs carrying dual conditional genes. These results describe the first models to genetically target RCs bypassing development.