Piezo2-expressing subsystem in mice

Abstract

The olfactory system plays a vital role in a rodent’s survival by guiding essential behaviors such as foraging, predator avoidance, social communication, and reproduction. The olfactory bulb (OB) serves as the first synaptic relay center in the olfactory information processing pathway. This sensory system is most often studied as a chemosensory organ, but recent studies have strengthened the view of the system as a multimodal system with multiple subsystems that detect mechanical and thermal stimuli in addition to chemosensory signals. The thesis focuses on investigating the mechanosensory information processing through the olfactory system. Previous studies have demonstrated that mechanical stimuli enhance odor perception. Articles have reported the presence of Piezo2, a mechanosensitive ion channel known to be present in the projection neurons of the OB. Based on these findings, we investigated Piezo2 expression in the mouse olfactory system to determine whether a distinct mechanosensory subsystem exists. We observed prominent expression of Piezo2 in a few distinct glomeruli interconnected by Piezo2 labeled fibers in the posterior OB. Further, we asked if these structures belong to the necklace glomerular subsystem and conducted multiple studies to characterize them. Our colocalization studies verified the necklace glomerular identity, and a detailed morphological analysis revealed heterogeneous glomerular sizes, a characteristic feature of the necklace glomerular system. Thus, our results demonstrate the presence of a novel and distinct Piezo2-expressing subsystem in the mouse olfactory pathway. Further studies will be required to fully characterize this subsystem and determine its functional relevance.