Latest cutting-edge sequencing has allowed researchers to obtain a full array of differentially expressed neuronal genes within the peripheral nervous system. Understanding this heterogeneity and functional implication could unveil new therapeutic targets towards a more precise medicine.
Combining a novel reporter mouse with Cre recombinase strategies, I examined the spatial and functional organization of transcriptomically different subpopulations of neurons in the mouse DRG in pathological and nonpathological states.
Results herein include: confirmation of Cre activity and specificity in all lines studied by RNA scope when compared to previous reports and transcriptomic analysis; significant upregulation of DRG gal expression after Complete Freund’s Adjuvant (CFA) induced inflamation; normal weight and exploratory behaviour for all lines tested; motor activity assessed by Rotarod not significant, but further motor coordination tests on animals missing Th DRG neurons showed significant impairment; noxious mechanosensation reduced in animals lacking SCN10aCre and Tmem45b DRG; confirmation of CGRP-positive neurons role in heat and cold perception as well as in the formalin inflammatory model; Von Frey hypersensitivity on animals lacking CGRP; and lastly TrkBpositive neurons responsible for significant deficits in mechanical hypersensitivity in the partial sciatic nerve ligation neuropathic pain model whilst no effect in
cancer induced bone pain model.
Parallelly, by reverse genetics approach, I explore the contribution of the Zfhx2 gene, whose mutation has been identified as responsible for the Marsili pain insensitivity syndrome, in two different animal models of nociception. Behavioural characterisation of bacterial artificial chromosome (BAC) transgenic mice bearing the orthologous murine mutation, as well as Zfhx2 null mutant mice, shows significant deficits in pain sensitivity in thermal and mechanical tests respectively.
In summary, as well as validating several new useful transgenic mouse lines, this thesis provides insights into genes and neuronal subpopulations important in pain pathways and provides potential platforms for translational studies of pain syndromes.