Complementary roles of KCa3.1 channels and β1-integrin during alveolar epithelial repair.
BACKGROUND
Extensive alveolar epithelial injury and remodelling is a common feature of acute lung injury and acute respiratory distress syndrome (ARDS) and it has been established that epithelial regeneration, and secondary lung oedema resorption, is crucial for ARDS resolution. Much evidence indicates that K(+) channels are regulating epithelial repair processes; however, involvement of the KCa3.1 channels in alveolar repair has never been investigated before.


RESULTS
Wound-healing assays demonstrated that the repair rates were increased in primary rat alveolar cell monolayers grown on a fibronectin matrix compared to non-coated supports, whereas an anti-β1-integrin antibody reduced it. KCa3.1 inhibition/silencing impaired the fibronectin-stimulated wound-healing rates, as well as cell migration and proliferation, but had no effect in the absence of coating. We then evaluated a putative relationship between KCa3.1 channel and the migratory machinery protein β1-integrin, which is activated by fibronectin. Co-immunoprecipitation and immunofluorescence experiments indicated a link between the two proteins and revealed their cellular co-distribution. In addition, we demonstrated that KCa3.1 channel and β1-integrin membrane expressions were increased on a fibronectin matrix. We also showed increased intracellular calcium concentrations as well as enhanced expression of TRPC4, a voltage-independent calcium channel belonging to the large TRP channel family, on a fibronectin matrix. Finally, wound-healing assays showed additive effects of KCa3.1 and TRPC4 inhibitors on alveolar epithelial repair.


CONCLUSIONS
Taken together, our data demonstrate for the first time complementary roles of KCa3.1 and TRPC4 channels with extracellular matrix and β1-integrin in the regulation of alveolar repair processes.
Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Tour Viger, 900 rue Saint-Denis, Montréal, Québec, H2X0A9, Canada. alban.girault37@gmail.com.|Département de médecine, Université de Montréal, CP6128, Succursale Centre-ville, Montréal, Québec, H3C3J7, Canada. alban.girault37@gmail.com.
Alban
A
Girault
Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Tour Viger, 900 rue Saint-Denis, Montréal, Québec, H2X0A9, Canada. jasmine.chebli@umontreal.ca.|Département de médecine, Université de Montréal, CP6128, Succursale Centre-ville, Montréal, Québec, H3C3J7, Canada. jasmine.chebli@umontreal.ca.
Jasmine
J
Chebli
Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Tour Viger, 900 rue Saint-Denis, Montréal, Québec, H2X0A9, Canada. anik.prive.chum@ssss.gouv.qc.ca.
Anik
A
Privé
Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Tour Viger, 900 rue Saint-Denis, Montréal, Québec, H2X0A9, Canada. tnguyenngan@jgh.mcgill.ca.|Département de médecine, Université de Montréal, CP6128, Succursale Centre-ville, Montréal, Québec, H3C3J7, Canada. tnguyenngan@jgh.mcgill.ca.
Nguyen Thu Ngan
NT
Trinh
Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Tour Viger, 900 rue Saint-Denis, Montréal, Québec, H2X0A9, Canada. emilie.maille.chum@ssss.gouv.qc.ca.
Emilie
E
Maillé
Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Tour Viger, 900 rue Saint-Denis, Montréal, Québec, H2X0A9, Canada. ryszard.grygorczyk@umontreal.ca.|Département de médecine, Université de Montréal, CP6128, Succursale Centre-ville, Montréal, Québec, H3C3J7, Canada. ryszard.grygorczyk@umontreal.ca.
Ryszard
R
Grygorczyk
Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Tour Viger, 900 rue Saint-Denis, Montréal, Québec, H2X0A9, Canada. emmanuelle.brochiero@umontreal.ca.|Département de médecine, Université de Montréal, CP6128, Succursale Centre-ville, Montréal, Québec, H3C3J7, Canada. emmanuelle.brochiero@umontreal.ca.
Emmanuelle
E
Brochiero
D056809:Alveolar Epithelial Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D002465:Cell Movement; D049109:Cell Proliferation; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005353:Fibronectins / Q000378:metabolism; D019012:Integrin beta1 / Q000378:metabolism*; D051660:Intermediate-Conductance Calcium-Activated Potassium Channels / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D008297:Male; D026902:Potassium Channel Blockers / Q000494:pharmacology; D011650:Pulmonary Alveoli / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D034622:RNA Interference; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D050052:TRPC Cation Channels / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D014162:Transfection; D014945:Wound Healing / Q000187:drug effects
D005353:Fibronectins; D019012:Integrin beta1; D051660:Intermediate-Conductance Calcium-Activated Potassium Channels; C491575:Kcnn4 protein, rat; D026902:Potassium Channel Blockers; D050052:TRPC Cation Channels; C489571:TRPC4 ion channel