咳と嚥下のスイッチ 喉に新たな感覚器官を発⾒〜咳治療に道筋、喉ごし感覚の⼀端か?〜

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2025-04-07 京都府立医科大学

京都府立医科大学の研究チームは、マウスを用いた実験で、喉の上皮に存在する新規の感覚細胞群を発見しました。これらの細胞は、苦味を持つ植物抽出物、タバコの煙、空気汚染物質、病原体関連物質などの侵害化学物質に応答し、喉頭では咳、咽頭では嚥下を引き起こすことが明らかになりました。さらに、これらの感覚器官がアレルギー性咳過敏症にも関与していることが示され、慢性咳嗽の新たな治療法開発への道を開く可能性があります。この研究成果は科学雑誌『Cell』に掲載されました。

<関連情報>

気道保護化学反射の神経伝達を仲介するチャネルシナプス Channel synapse mediates neurotransmission of airway protective chemoreflexes

Shogo Soma∙ Norihito Hayatsu∙ Kengo Nomura∙ … ∙ Nobuhiko Ohno∙ Yasushi Okazaki∙ Akiyuki Taruno
Cell  Published:April 4, 2025
DOI:https://doi.org/10.1016/j.cell.2025.03.007

Graphical abstract

咳と嚥下のスイッチ 喉に新たな感覚器官を発⾒〜咳治療に道筋、喉ごし感覚の⼀端か?〜

Highlights

  • Throat Pou2f3+ chemosensory cells (PCCs) form channel synapses with vagal neurons
  • Hypopharyngeal and laryngeal PCCs express T2Rs, receptors for noxious chemicals
  • Hypopharyngeal PCCs trigger swallowing; laryngeal PCCs trigger coughing
  • Laryngeal PCCs mediate allergic hyperresponsivity to T2R ligands

Summary

Neural reflexes to chemicals in the throat protect the airway from aspiration and infection. Mechanistic understanding of these reflexes remains premature, exemplified by chronic cough—a sensitized cough reflex—being a prevalent unmet clinical need. Here, in mice, a whole-body search for channel synapses—featuring CALHM1/3 channel-mediated neurotransmitter release—and single-cell transcriptomics uncovered subclasses of the Pou2f3+ chemosensory cell family in the throat communicating with vagal neurons via this synapse. They express G protein-coupled receptors (GPCRs) for noxious chemicals, T2Rs, which upon stimulation trigger swallow and cough-like expulsive reflexes in the hypopharynx and larynx, respectively. These reflexes were abolished by Calhm3 and Pou2f3 knockout and could be triggered by targeted optogenetic stimulation. Furthermore, aeroallergen exposure augmented CALHM3-dependent expulsive reflex. This study identifies Pou2f3+ epithelial cells with channel synapses as chemosensory end organs of airway protective reflexes and sites of their hyperresponsiveness, advancing mechanistic understanding of airway defense programs with distinct therapeutic potential.

医療・健康
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