TRPV4 activation in Schwann cells mediates mechanically induced pain of oral cancer

Yatendra Mulpuri ^1,2* Tu H. Nguyen ^1,2 Kenji Inoue ^1,2 Grace Harden ^1,2 Samuel J. Nicholson ^1,2,3 Anisa Seenauth ^2,4 Yan Huang ^2,4 Keylin G. Escobar ^2,4 Yalda Moayedi ^2,4 Nigel W. Bunnett ^2,4,5,6 Donna G. Albertson ^1,2 Brian L. Schmidt ^1,2,6*

• ¹ NYU Dentistry Translational Research Center, New York University Dentistry, New York, United States
• ² NYU Pain Research Center, New York University, New York, United States
• ³ Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
• ⁴ Department of Molecular Pathobiology, New York University Dentistry, New York, United States
• ⁵ Neuroscience Institute, New York University Langone Health, New York, United States
• ⁶ Department of Neuroscience and Physiology, New York University Grossman School of Medicine, New York, United States

Introduction: Patients with oral cancer often experience intense functional pain due to mechanical stimulation at the cancer site. The role of mechanosensitive ion channels in oral cancer pain, such as TRPV4, is not fully understood.Objectives: Our objective was to investigate the role of Schwann cell TRPV4 in oral cancer pain.We examined the impact of TRPV4 inhibition on oral cancer pain in NU/J and C57BL/6J mice injected with human tongue cancer cell line (HSC-3) and mouse oral cancer cell line (MOC2) in the hind paw or tongue. Mechanical and heat sensitivity were assessed using the von Frey and Hargreaves tests, respectively. TRPV4 expression and functional activity in Schwann cells were analyzed using immunohistochemistry, qRT-PCR, Ca 2+ imaging, and patch clamp electrophysiology. The effect of TRPV4 activation on Schwann cell responses to mechanical stimulation was evaluated using a piezo stimulator. Conditioned media from TRPV4activated Schwann cells were injected into the mouse paw to evaluate the contribution of TRPV4 in Schwann cells to mechanical hypersensitivity.Results: TRPV4 inhibition reduced paw cancer mechanical nociception in mice dosedependently without affecting heat sensitivity. TRPV4 inhibition also decreased facial nociception in tongue cancer mice. TRPV4 was expressed mainly on the plasma membrane of mouse Schwann cells and activation of TRPV4 induced Ca 2+ responses and whole-cell membrane currents in human Schwann cells. Mechano-activated currents in human Schwann cells were inhibited by the TRPV4 antagonist HC-067047. Schwann cell-conditioned media induced mechanical hypersensitivity in mice, which was blocked by pre-treatment with HC-067047.TRPV4 activation plays a role in mediating mechanically induced pain of oral cancer.