Anti-NPPB monoclonal antibody, clone 0I7I5B8

Noxious mechanical information is transmitted through molecularly distinct nociceptors, with pinprick-evoked sharp sensitivity via A-fiber nociceptors marked by developmental expression of the neuropeptide Y receptor 2 (Npy2r) and von Frey filament-evoked punctate pressure information via unmyelinated C fiber nociceptors marked by MrgprD. However, the molecular programs controlling their development are only beginning to be understood. Here we demonstrate that Npy2r-expressing sensory neurons are in fact divided into two groups, based on transient or persistent Npy2r expression. Npy2r-transient neurons are myelinated, likely including A-fiber nociceptors, whereas Npy2r-persistent ones belong to unmyelinated pruriceptors that co-express Nppb. We then showed that the transcription factors NFIA and Runx1 are necessary for the development of Npy2r-transient A-fiber nociceptors and MrgprD(+) C-fiber nociceptors, respectively. Behaviorally, mice with conditional knockout of Nfia, but not Runx1 showed a marked attenuation of pinprick-evoked nocifensive responses. Our studies therefore identify a transcription factor controlling the development of myelinated nociceptors.

The ciliary transport is controlled by two parameters of the ciliary beating, frequency (CBF) and amplitude. In this study, we developed a novel method to measure both CBF and ciliary bend distance (CBD, an index of ciliary beating amplitude) in ciliated human nasal epithelial cells (cHNECs) in primary culture, which are prepared from patients contracting allergic rhinitis and chronic sinusitis. An application of Cl--free NO3- solution or bumetanide (an inhibitor of Na+/K+/2Cl(-) cotransport), which decreases intracellular Cl- concentration ([Cl-](i)), increased CBD, not CBF, at 37 degrees C; however, it increased both CBD and CBF at 25 degrees C. Conversely, addition of Cl- channel blockers (5-nitro-2-(3-phenylpropylamino) benzoic acid(NPPB) and 4-[[4-Oxo-2-thioxo-3-[3-trifluoromethyl]phenyl]-5-thiazolidinylidene]methyl] benzoic acid(CFTR(inh)-172)), which increase [Cl-](i), decreased both CBD and CBF, suggesting that CFTR plays a crucial role for maintaining [Cl-](i) in these cells. We speculate that Cl- modulates activities of the molecular motors regulating both CBD and CBF in cHNECs. Moreover, application of the CO2/HCO3--free solution did not change intracellular pH (pH(i)), and addition of an inhibitor of carbonic anhydrase (acetazolamide) sustained pH(i) increase induced by the NH4+ pulse, which transiently increased pH(i) in the absence of acetazolamide. These results indicate that the cHNEC produces a large amount of CO2, which maintains a constant pH(i) even under the CO2/HCO3--free condition.