Citation

Dorsal root ganglion (DRG) neurons are classified into distinct types to mediate the somatosensation with different modalities. Recently, transcriptional profilings of DRG neurons by single-cell RNA-sequencing have provided new insights into the neuron typing and functional properties. Zinc-finger CCHC domain-containing 12 (Zcchc12) was reported to be the representative marker for a subtype of Gal-positive (Gal+) DRG neurons. However, the characteristics and functions of Zcchc12+ neurons are largely unknown. Here, we genetically labelled Zcchc12+ neurons in Zcchc12-CreERT2::Ai9 mice, and verified that Zcchc12 represented a new subpopulation of DRG neurons in both sexes. Zcchc12+ neurons centrally innervated the superficial laminae in spinal dorsal horn, and peripherally terminated as free nerve endings in the epidermis and cluster-shaped fibers in the dermis of footpads and nearby. Besides, Zcchc12+ neurons also formed circumferential endings surround the hair follicles in hairy skin. Functionally, in vivo calcium imaging in DRGs revealed that Zcchc12+ neurons were polymodal nociceptors and could be activated by mechanical and noxious thermal stimuli. Behavioral tests showed that selective ablation of Zcchc12+ DRG neurons reduced the sensitivity to noxious heat in mice. Taken together, we identify a new subpopulation of Zcchc12+ nociceptors essential for noxious heat sensation.SIGNIFICANCE STATEMENT:Zcchc12 represents a new subpopulation of DRG neurons. The characteristics and functions of Zcchc12+ neurons are largely unknown. Here we genetically labelled Zcchc12 neurons, and showed that the fibers of Zcchc12+ DRG neurons projected to superficial lamina at spinal dorsal horn, and innervated skin as free nerve endings in the epidermis and cluster-shaped fibers in the dermis of footpads and nearby. Functionally, Zcchc12+ DRG neurons responded to noxious mechanical and heat stimuli. Ablation of Zcchc12+ DRG neurons impaired the sensation of noxious heat in mice. Therefore, we identify a new subpopulatipn of DRG neurons required for noxious heat sensation.