Translational control in the spinal cord regulates gene expression and pain hypersensitivity in the chronic phase of neuropathic pain.

Sensitization of spinal nociceptive circuits plays a crucial role in neuropathic pain. This sensitization depends on new gene expression that is primarily regulated via transcriptional and translational control mechanisms. The relative roles of these mechanisms in regulating gene expression in the clinically relevant chronic phase of neuropathic pain are not well understood. Here, we show that changes in gene expression in the spinal cord during the chronic phase of neuropathic pain are substantially regulated at the translational level. Downregulating spinal translation at the chronic phase alleviated pain hypersensitivity. Cell-type-specific profiling revealed that spinal inhibitory neurons exhibited greater changes in translation after peripheral nerve injury compared to excitatory neurons. Notably, increasing translation selectively in all inhibitory neurons or parvalbumin-positive (PV+) interneurons, but not excitatory neurons, promoted mechanical pain hypersensitivity. Furthermore, increasing translation in PV+ neurons decreased their intrinsic excitability and spiking activity, whereas reducing translation in spinal PV+ neurons prevented the nerve injury-induced decrease in excitability. Thus, translational control mechanisms in the spinal cord, particularly in inhibitory neurons, play a role in mediating neuropathic pain hypersensitivity.

Protocol for measuring protein synthesis in specific cell types in the mouse brain using in vivo non-canonical amino acid tagging.

The fluorescent non-canonical amino acid tagging (FUNCAT) technique has been used to visualize newly synthesized proteins in cell lines and tissues. Here, we present a protocol for measuring protein synthesis in specific cell types in the mouse brain using in vivo FUNCAT. We describe steps for metabolically labeling newly synthesized proteins with azidohomoalanine, which introduces an azide group into the polypeptide. We then detail procedures for binding a fluorophore-conjugated alkyne to the azide group to allow its visualization. For complete details on the use and execution of this protocol, please refer to tom Dieck et al. (2012)1 and Hooshmandi et al. (2023).2.