Calmodulin and protein kinases A/G mediate ciliary beat response in the human nasal epithelium

Abstract Purpose Nasal irrigation is an effective method for alleviating several nasal symptoms and regular seawater-based nasal irrigation is useful for maintaining nasal hygiene which is essential for appropriate functioning of the nose and for preventing airborne particles including some pollutants, pathogens, and allergens from moving further in the respiratory system. However, safety studies on seawater-based nasal irrigation are scarce. In this study, the safety and efficacy of a diluted isotonic seawater solution (Stérimar Nasal Hygiene, SNH) in maintaining nasal homeostasis were evaluated in vitro. Methods Safety was assessed by measuring tissue integrity via transepithelial electrical resistance (TEER). Efficacy was measured by mucociliary clearance (MCC), mucin secretion, and tissue re-epithelization (wound repair) assays. All assays were performed using a 3D reconstituted human nasal epithelium model. Results In SNH-treated tissues, TEER values were statistically significantly lower than the untreated tissues; however, the values were above the tissue integrity limit. SNH treatment significantly increased MCC (88 vs. 36 µm/s, p < 0.001) and mucin secretion (1717 vs. 1280 µg/ml, p < 0.001) as compared to untreated cultures. Faster wound closure profile was noted upon pre-SNH treatment as compared to classical isotonic saline solution pre-treatment (90.5 vs. 50.7% wound closure 22 h after wound generation). Conclusion SNH did not compromise the integrity of the nasal epithelium in vitro. Furthermore, SNH was effective for removal of foreign particles through MCC increase and for enhancing wound repair on nasal mucosa.

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Calmodulin Regulates Ciliary Beats in the Human Nasal Mucosa Through Adenylate/Guanylate Cyclases and Protein Kinases A/G

International Archives of Allergy and Immunology ◽

10.1159/000515225 ◽

2021 ◽

pp. 1-7

Author(s):

Thi Nga Nguyen ◽

Hideaki Suzuki ◽

Jun-ichi Ohkubo ◽

Tetsuro Wakasugi ◽

Takuro Kitamura

Keyword(s):

Protein Kinase ◽

Adenylate Cyclase ◽

Protein Kinases ◽

Nasal Mucosa ◽

Guanylate Cyclase ◽

Regulatory Pathway ◽

Calmodulin Antagonist ◽

Human Nasal Mucosa ◽

Cyclase Activator ◽

Ciliary Beat

Background: The ciliary beat of the airway epithelium, including the sinonasal epithelium, has a significant role in frontline defense and is thought to be controlled by the level of intracellular Ca2+. Involvement of calmodulin and adenylate/guanylate cyclases in the regulation of ciliary beats has been reported, and here we investigated the interrelation between these components of the ciliary beat regulatory pathway. Methods: The inferior turbinates were collected from 29 patients with chronic hypertrophic rhinitis/rhinosinusitis during endoscopic sinonasal surgery. The turbinate mucosa was cut into thin strips, and mucociliary movement was observed under a phase-contrast light microscope equipped with a high-speed digital video camera. Results: The ciliary beat frequency (CBF) was significantly increased by stimulation with 100 μM CALP3 (calmodulin agonist), which was completely suppressed by adding 100 µM SQ22536 (adenylate cyclase inhibitor) and 10 µM ODQ (guanylate cyclase inhibitor) together and by adding 1 µM KT5720 (protein kinase A inhibitor) and 1 µM KT5823 (protein kinase G inhibitor) together. The CBF was significantly increased by stimulation with 10 µM forskolin (adenylate cyclase activator) and 10 µM BAY41-2272 (guanylate cyclase activator) and by stimulation with 100 µM 8-bromo-cAMP (cAMP analog) and 100 µM 8-bromo-cGMP (cGMP analog), which was not changed by adding 1 µM calmidazolium (calmodulin antagonist). Conclusions: These results confirmed that the regulatory pathway of ciliary beats in the human nasal mucosa involves calmodulin, adenylate/guanylate cyclases, and protein kinases A/G and indicate that adenylate/guanylate cyclases and protein kinases A/G act downstream of calmodulin, but not vice versa, and that these cyclases relay calmodulin signaling.

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