Nociceptor-specific gene deletion using heterozygous NaV1.8-Cre recombinase mice

Abstract

NaV1.8 is a voltage-gated sodium channel expressed only in a subset of sensory neurons of which more than 85% are nociceptors. In order to delete genes in nociceptive neurons, we generated heterozygous transgenic mice expressing Cre recombinase under the control of the NaV1.8 promoter. Functional Cre recombinase expression replicated precisely the expression pattern of NaV1.8. Cre expression began at embryonic day 14 in small diameter neurons in dorsal root, trigeminal and nodose ganglia, but was absent in non-neuronal or CNS tissues into adulthood. Sodium channel subtypes were normal in isolated DRG neurons. Pain behaviour in response to mechanical or thermal stimuli, and in acute, inflammatory and neuropathic pain was also normal. These data demonstrate that the heterozygous NaV1.8-Cre mouse line is a useful tool to analyse the effects of deleting floxed genes on pain behaviour.

A sensory subpopulation depends on vesicular glutamate transporter 2 for mechanical pain, and together with substance P, inflammatory pain

“…Na v 1.8 Cre -positive neurons were absent in the spinal cord ( Fig. 1 A and B), consistent with a previous report (16). The majority of Na v 1.8 Cre -positive projections were detected in the dorsal spinal cord superficial to lamina 2, defined by IB4 binding, whereas a minor part of the fibers was found in the deeper lamina (Fig.…”

“…1C). To determine the overall coverage of the Na v 1.8 Cre line (16) and to verify the expression of Cre in Na v 1.8-expressing neurons, both single-cell PCR and immunohistochemistry (IHC) analysis were performed. Using single-cell PCR, 68% of randomly picked control DRG neurons were shown to express Na v 1.8 mRNA at P2, whereas 87% of Na v 1.8 Cre -active neurons expressed Na v 1.8 mRNA at the same age (Fig.…”

“…To study the role of VGLUT2-mediated glutamatergic transmission in Na v 1.8 Cre -positive neurons, we crossed Vglut2 f/f mice (11) with Na v 1.8 Cre mice (16) to generate mice lacking Vglut2 in Na v 1.8 Creexpressing neurons (Vglut2 f/f ;Na v 1.8 Cre ). Such mice were born with a normal Mendelian ratio and were viable to adulthood (54% Vglut2 f/f ;Na v 1.8 Cre , n = 145).…”

“…To study the contribution of VGLUT2-mediated signaling in various pain states, we examined mice lacking Vglut2 in the primary sensory subpopulation defined by Na v 1.8 Cre expression (16). This allowed for a comparison of the pain conditions in the absence of the Na v 1.8 Cre population itself (7) or after elimination of VGLUT2-mediated signaling in the same population.…”

Dysregulation of voltage-gated sodium channels by ubiquitin ligase NEDD4-2 in neuropathic pain

“…Mice carrying a homozygous Nedd4L flox allele (Nedd4L fl/fl ) (30) were crossed with mice heterozygously expressing Cre recombinase under the control of the Na v 1.8 promoter (referred to as SNS-Cre), which is predominantly active in DRG nociceptive neurons (31). Cre expression in this mouse line has been extensively characterized (32) and differs from another Na v 1.8-Cre mouse line generated by the Wood laboratory (33). NEDD4-2 expression was greatly reduced in the DRG neurons of SNSNedd4L -/-mice ( Figure 4, A-E).…”