Transient receptor potential cation channel, subfamily V, member 4 and airway sensory afferent activation: Role of adenosine triphosphate

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• 作者：Sara J. Bonvini ; PhD^a ; ^&lowast ; ; Mark A. Birrell ; PhD^a ; ^&lowast ; ; Megan S. Grace ; PhD^b ; Sarah A. Maher ; PhD^a ; John J. Adcock ; PhD^a ; Michael A. Wortley ; PhD^a ; Eric Dubuis ; PhD^a ; Yee-Man Ching ; MRes^c ; Anthony P. Ford ; PhD^e ; Fisnik Shala ; MD^a ; Montserrat Miralpeix ; PhD^f ; Gema Tarrason ; PhD^f ; Jaclyn A. Smith ; PhD^d ; Maria G. Belvisi ; PhD^a ; ^{m.belvisi@imperial.ac.uk" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Transient receptor potential ; sensory nerves ; vagus ; cough ; ion channels ; hypotonicity ; ATP
• 刊名：Journal of Allergy and Clinical Immunology
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：138
• 期：1
• 页码：249-261.e12
• 全文大小：3250 K

文摘

Sensory nerves innervating the airways play an important role in regulating various cardiopulmonary functions, maintaining homeostasis under healthy conditions and contributing to pathophysiology in disease states. Hypo-osmotic solutions elicit sensory reflexes, including cough, and are a potent stimulus for airway narrowing in asthmatic patients, but the mechanisms involved are not known. Transient receptor potential cation channel, subfamily V, member 4 (TRPV4) is widely expressed in the respiratory tract, but its role as a peripheral nociceptor has not been explored.

Objective

15">We hypothesized that TRPV4 is expressed on airway afferents and is a key osmosensor initiating reflex events in the lung.

Methods

We used guinea pig primary cells, tissue bioassay, in vivo electrophysiology, and a guinea pig conscious cough model to investigate a role for TRPV4 in mediating sensory nerve activation in vagal afferents and the possible downstream signaling mechanisms. Human vagus nerve was used to confirm key observations in animal tissues.

Results

Here we show TRPV4-induced activation of guinea pig airway–specific primary nodose ganglion cells. TRPV4 ligands and hypo-osmotic solutions caused depolarization of murine, guinea pig, and human vagus and firing of Aδ-fibers (not C-fibers), which was inhibited by TRPV4 and P2X3 receptor antagonists. Both antagonists blocked TRPV4-induced cough.

Conclusion

This study identifies the TRPV4-ATP-P2X3 interaction as a key osmosensing pathway involved in airway sensory nerve reflexes. The absence of TRPV4-ATP–mediated effects on C-fibers indicates a distinct neurobiology for this ion channel and implicates TRPV4 as a novel therapeutic target for neuronal hyperresponsiveness in the airways and symptoms, such as cough.