Following the p63/Keratin5 Basal Cells in the Sensory and Non-sensory Epithelia of The Vomeronasal Organ

Abstract

The Vomeronasal organ (VNO) is a part of the accessory olfactory system, which is responsible for detecting pheromones, chemical factors that trigger a spectrum of sexual and social behaviors. The vomeronasal epithelium (VNE) shares several features with the epithelium of the main olfactory epithelium (MOE). However, it is a distinct neuroepithelium populated by chemosensory neurons that differ from the olfactory sensory neurons (OSNs) in cellular structure, receptor expression, and connectivity. The vomeronasal organ of rodents comprises a sensory epithelium and a thin non-sensory epithelium that morphologically resembles the respiratory epithelium. Sox2-positive cells have been previously identified as the stem cell population that gives rise to neuronal progenitors in MOE and VNE. In addition to these, the MOE also comprises p63 positive horizontal basal cells (HBCs), a second pool of quiescent stem cells that become active in response to injury. Immunolabeling against the transcription factor p63, Keratin-5 (Krt5), Krt14 and Krt5Cre tracing experiments highlighted the existence of horizontal basal cells distributed along the basal lamina of the VNO forming from progenitors along the basal lamina of the marginal zones. Moreover, these experiments revealed that the NSE of rodents is, like the respiratory epithelium, a stratified epithelium where the p63/Krt5+ basal cells self-replicate and give rise to the apical columnar cells facing the lumen of the VNO.