Open AccessLarge pH oscillations promote host defense against human airways infection
Author(s) -
Dusik Kim,
Jie Liao,
Nathan Scales,
Carolina Martini,
Xiaojie Luan,
Asmahan AbuArish,
Renaud Robert,
Yishan Luo,
Geoffrey A. McKay,
Dao Nguyen,
Marc A. Tewfik,
Charles Poirier,
Elias Matouk,
Juan P. Ianowski,
Saul Frenkiel,
John W. Hanrahan
Publication year - 2021
Publication title -
the journal of experimental medicine/the journal of experimental medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 8.483
H-Index - 448
eISSN - 1540-9538
pISSN - 0022-1007
DOI - 10.1084/jem.20201831
Subject(s) - cystic fibrosis , bicarbonate , mucus , airway , carbonic anhydrase , microbiology and biotechnology , respiratory system , inhalation , immunology , mucociliary clearance , chemistry , biology , medicine , lung , biochemistry , enzyme , anesthesia , anatomy , ecology
The airway mucosal microenvironment is crucial for host defense against inhaled pathogens but remains poorly understood. We report here that the airway surface normally undergoes surprisingly large excursions in pH during breathing that can reach pH 9.0 during inhalation, making it the most alkaline fluid in the body. Transient alkalinization requires luminal bicarbonate and membrane-bound carbonic anhydrase 12 (CA12) and is antimicrobial. Luminal bicarbonate concentration and CA12 expression are both reduced in cystic fibrosis (CF), and mucus accumulation both buffers the pH and obstructs airflow, further suppressing the oscillations and bacterial-killing efficacy. Defective pH oscillations may compromise airway host defense in other respiratory diseases and explain CF-like airway infections in people with CA12 mutations.