Non-olfactory cells have excellent biosensor potential because they express functional olfactory receptors (ORs) and are non-neuronal cells that are easy to culture. ORs are G-protein coupled receptors (GPCRs), and there is a well-established link between different classes of G-proteins and cytoskeletal structure changes affecting cellular morphology that has been unexplored for odorant sensing. Thus, the present study was conducted to determine if odorant binding in non-olfactory cells causes cytoskeletal changes that will lead to cell changes detectable by electric cell-substrate impedance sensing (ECIS). To this end, we used the human umbilical vein endothelial cells (HUVECs), which express OR10J5, and the human keratinocyte (HaCaT) cells, which express OR2AT4. Using these two different cell barriers, we showed that odorant addition, lyral and Sandalore, respectively, caused an increase in cAMP, changes in the organization of the cytoskeleton, and a decrease in the integrity of the junctions between the cells, causing a decrease in cellular electrical resistance. In addition, the random cellular movement of the monolayers (micromotion) was significantly decreased after odorant exposure. Collectively, these data demonstrate a new physiological role of olfactory receptor signaling in endothelial and epithelial cell barriers and represent a new label-free method to detect odorant binding.

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Olfactory receptors (ORs) are expressed in various non-nasal tissues; however, their physiological roles are largely unknown. ORs are G-protein coupled receptors (GPCRs), and there is a well-established link between different classes of G-proteins and cytoskeletal structure changes affecting cellular morphology that has been unexplored after odorant binding. Thus, the present study was conducted to determine if odorant binding in non-olfactory cells causes cytoskeletal changes that lead to cell morphological changes. To this end, human umbilical vein endothelial cells (HUVECs), which express OR10J5, and human keratinocyte (HaCaT) cells, which express OR2AT4, were used to conduct this study. Using these two different cell lines, it was shown that odorant addition, lyral and Sandalore, respectively, caused a dose-dependent increase in cAMP. Furthermore, HUVECs exposed to lyral exhibited a disassembly of the tubulin-containing microtubules and an increase in cortical actin microfilaments, whereas HaCaT cell exposure to Sandalore exhibited both a disassembly of the tubulin-containing microtubules and cortical actin microfilaments. Even though the endothelial and epithelial cell lines had different cytoskeletal responses to odorant exposure, both exhibited a change in cellular morphology as detected by a decrease in electrical resistance using Electric Cell-substrate Impedance Sensing (ECIS; Applied Biophysics, Inc., Troy, NY). Interestingly, these odorant-induced cytoskeletal and morphological changes occurred rapidly (under 1 hour) but returned to normal after 20 hours, highlighting the complexity of olfactory signaling, which may involve desensitization of the signaling pathway and/or internalization of the odorant receptor. Future experiments will further elucidate the olfactory receptor signaling mechanism in endothelial and epithelial cells so that their physiological role can be fully understood. Funded by Army Research Office STTR #W911NF-19-P-0014 and W911NF-20-C-0014, the SUNY Cortland Undergraduate Research Council, and Research and Sponsored Programs. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.