Characterization of transgenic mouse lines for selectively targeting glial cells in dorsal root ganglia

Abstract

25The importance of glial cells in the modulation of neuronal processes is now generally accepted. In 26 particular, enormous progress in our understanding of astrocytes and microglia physiology in the 27 central nervous system (CNS) has been made in recent years, due to the development of genetic and 28 molecular toolkits. However, the roles of satellite glial cells (SGCs) and macrophagesthe peripheral 29 counterparts of astrocytes and microgliaremain poorly studied despite their involvement in 30 debilitating conditions, such as pain. Here, we characterized in dorsal root ganglia (DRGs), different 31 genetically-modified mouse lines previously used for studying astrocytes and microglia, with the goal 32 to implement them for investigating DRG SGC and macrophage functions. Although SGCs and 33 astrocytes share some molecular properties, most tested transgenic lines were found to not be suitable 34for studying selectively a large number of SGCs within DRGs. Nevertheless, we identified and 35 validated two mouse lines: (i) a CreERT2 recombinase-based mouse line allowing transgene 36 expression almost exclusively in SGCs and in the vast majority of SGCs, and (ii) a GFP-expressing 37 line allowing the selective visualization of macrophages. In conclusion, among the tools available for 38 exploring astrocyte functions, a few can be used for studying selectively a great proportion of SGCs. 39Thus, efforts remain to be made to characterize other available mouse lines as well as to develop, 40 rigorously characterize and validate new molecular tools to investigate the roles of DRG SGCs, but 41 also macrophages, in health and disease. 42 43 44 45 46 47 48 49 50 343 We gratefully acknowledge S. Antoine and S. Guinoiseau for animal care; S. Guinoiseau and P. 344 Meriau for dissecting some tissues; C. Ayissi Sama and M. Tantouch for slicing some tissues; F. 345 Charbonnier, B. Delhomme, P. Djian, and M. Oheim for sharing pieces of equipment (cryostat, 346 microscopes); J. Strinnakre, S. Guinoiseau and P. Meriau for proof reading; and both the imaging and 347 mouse core facilities, which are supported and funded by the CNRS, INSERM and Paris Descartes 348University.