title: Ca2+/calmodulin-dependent protein kinase IIβ and IIδ mediate TGFβ-induced transduction of fibronectin and collagen in human pulmonary fibroblasts.
abstract: It is now clear that in addition to activating several complex kinase pathways (Smad, MAP kinase, PI3 kinase), TGFβ also acts by elevating cytosolic Ca2+concentration within human pulmonary fibroblasts. Ca2+/calmodulin-dependent protein kinase II (CamK II) is also known to regulate gene expression in fibroblasts. In this study, we examined the interactions between calcium signaling, activation of CamK and other kinases, and extracellular matrix (ECM) gene expression. Human pulmonary fibroblasts were cultured and stimulated with artificially generated Ca2+pulses in the absence of TGFβ, or with TGFβ (1 nM) or vehicle in the presence of various blockers of Ca2+signaling. PCR and Western blotting were used to measure gene expression and protein levels, respectively. We found that Ca2+pulses in the absence of TGFβ increased ECM gene expression in a pulse frequency-dependent manner, and that blocking Ca2+signaling and the CamK II pathway significantly reduced TGFβ-mediated ECM gene expression, without having any effects on other kinase pathways (Smad, PI3 kinase, or MAP kinase). We also found that TGFβ elevated the expression of CamK IIβ and CamK IIδ, while siRNA silencing of those two subtypes significantly reduced TGFβ-mediated expression of collagen A1 and fibronectin 1. Our data suggest that TGFβ induces the expression of CamK IIβ and CamK IIδ, which in turn are activated by TGFβ-evoked Ca2+waves in a frequency-dependent manner, leading to increased expression of ECM proteins.
authors.affiliation: Firestone Institute for Respiratory Health, St. Joseph's Hospital, Department of Medicine, McMaster University, Hamilton, Ontario, Canada smukher@mcmaster.ca subh812002@gmail.com.
authors.forename: Subhendu
authors.initials: S
authors.lastname: Mukherjee
authors.affiliation: Firestone Institute for Respiratory Health, St. Joseph's Hospital, Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Wei
authors.initials: W
authors.lastname: Sheng
authors.affiliation: Firestone Institute for Respiratory Health, St. Joseph's Hospital, Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Rui
authors.initials: R
authors.lastname: Sun
authors.affiliation: Firestone Institute for Respiratory Health, St. Joseph's Hospital, Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Luke J
authors.initials: LJ
authors.lastname: Janssen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015153:Blotting, Western; D020013:Calcium Signaling; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000378:metabolism*; D024042:Collagen Type I / Q000378:metabolism*; D000090602:Collagen Type I, alpha 1 Chain; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism*; D005353:Fibronectins / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008168:Lung / Q000166:cytology*; D008297:Male; D008875:Middle Aged; D010766:Phosphorylation / Q000187:drug effects; D012433:Ryanodine / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects* / Q000235:genetics; D016212:Transforming Growth Factor beta / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D024042:Collagen Type I; D000090602:Collagen Type I, alpha 1 Chain; D016326:Extracellular Matrix Proteins; D005353:Fibronectins; D007211:Indoles; D007527:Isoenzymes; D016212:Transforming Growth Factor beta; D012433:Ryanodine; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; C000543:cyclopiazonic acid
keywords: Ca signaling; Cam kinase; extracellular matrix; fibrosis