Expression of T-Type Voltage-Gated Calcium Channel in the Cilia of Human Nasal Epithelial Cells

Thi Nga Nguyen; Hideaki Suzuki; Ryoko Baba; Yasuhiro Yoshida; Jun-Ichi Ohkubo; Tetsuro Wakasugi; Takuro Kitamura

doi:10.1159/000521765

Expression of T-Type Voltage-Gated Calcium Channel in the Cilia of Human Nasal Epithelial Cells

Int Arch Allergy Immunol. 2022;183(6):579-590. doi: 10.1159/000521765. Epub 2022 Jan 31.

Authors

Thi Nga Nguyen^{1

2}, Hideaki Suzuki¹, Ryoko Baba³, Yasuhiro Yoshida⁴, Jun-Ichi Ohkubo¹, Tetsuro Wakasugi¹, Takuro Kitamura¹

Affiliations

¹ Department of Otorhinolaryngology-Head and Neck Surgery, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
² Faculty of Public Health, Vinh Medical University, Vinh, Vietnam.
³ Department of Anatomy, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
⁴ Department of Immunology and Parasitology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.

Abstract

Introduction: The mucociliary transport function of the airway epithelium is largely dependent on ciliary beating. The control signal of ciliary beating is thought to be intracellular Ca2+. We herein investigated the expression of T-type voltage-gated calcium channel (VGCC), a generator of intracellular Ca2+ oscillation, in the human nasal mucosa.

Methods: The inferior turbinate was collected from patients with chronic hypertrophic rhinitis. The expression of T-type VGCC α1 subunits was examined by immunohistochemistry, transmission immunoelectron microscopy, Western blot, and real-time reverse transcription-polymerase chain reaction (RT-PCR). Participation of T-type VGCC in the ciliary beat regulation was examined by pharmacological inhibition tests using specific blockers of T-type VGCC in ex vivo measurements of the ciliary beat frequency (CBF) and ATP release and in intracellular Ca2+ imaging of isolated ciliated cells.

Results: Immunohistochemical staining showed the expressions of T-type VGCC α1 subunits, Cav3.1 and Cav3.3, on the surface of the epithelial cells. At the ultrastructural level, immunoreactivity for Cav3.1 was localized on the surface of the cilia, and that for Cav3.3 was localized in the cilia and at the base of the cilia. The existence of Cav3.1 and Cav3.3 was confirmed at the protein level by Western blot and at the transcriptional level by real-time RT-PCR. Specific blockers of T-type VGCC, mibefradil and NNC 55-0396, significantly inhibited CBF. These blockers also inhibited a CBF increase induced by 8-bromo-cAMP/8-bromo-cGMP and significantly lowered the intracellular Ca2+ level of isolated ciliated cells in a time-dependent manner. On the other hand, the ATP release from the nasal mucosa was not changed by mibefradil or NNC 55-0396.

Conclusion: These results indicate that T-type VGCC α1 subunits, Cav3.1 and Cav3.3, exist at the cilia of the nasal epithelial cells and participate in the regulation of ciliary beating and that these channels act downstream of cAMP/cGMP.

Keywords: Ciliary beat; Nasal mucosa; T-type voltage-gated calcium channel; Turbinate.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adenosine Triphosphate / metabolism
Calcium / metabolism
Calcium Channels, T-Type* / genetics
Calcium Channels, T-Type* / metabolism
Cilia* / physiology
Cyclic GMP
Epithelial Cells / metabolism
Humans
Mibefradil / metabolism
Mibefradil / pharmacology
Nasal Mucosa / metabolism

Substances

Calcium Channels, T-Type
Mibefradil
Adenosine Triphosphate
Cyclic GMP
Calcium

Grants and funding

This study was supported by a Grant-in-Aid for Scientific Research (C) (No. 19K09879; 2019-2022) to H.S. from the Japan Society for the Promotion of Science.