Altered intercellular communication in lung fibroblast cultures from patients with idiopathic pulmonary fibrosis.
BACKGROUND
Gap junctions are membrane channels formed by an array of connexins which links adjacent cells realizing an electro- metabolic synapse. Connexin-mediated communication is crucial in the regulation of cell growth, differentiation, and development. The activation and proliferation of phenotypically altered fibroblasts are central events in the pathogenesis of idiopathic pulmonary fibrosis. We sought to evaluate the role of connexin-43, the most abundant gap-junction subunit in the human lung, in the pathogenesis of this condition.


METHODS
We investigated the transcription and protein expression of connexin-43 and the gap-junctional intercellular communication (GJIC) in 5 primary lung fibroblast lines derived from normal subjects (NF) and from 3 histologically proven IPF patients (FF).


RESULTS
Here we show that connexin-43 mRNA was significantly reduced in FF as demonstrated by standard and quantitative RT-PCR. GJIC was functionally evaluated by means of flow-cytometry. In order to demonstrate that dye spreading was taking place through gap junctions, we used carbenoxolone as a pharmacological gap-junction blocker. Carbenoxolone specifically blocked GJIC in our system in a concentration dependent manner. FF showed a significantly reduced homologous GJIC compared to NF. Similarly, GJIC was significantly impaired in FF when a heterologous NF line was used as dye donor, suggesting a complete defect in GJIC of FF.


CONCLUSIONS
These results suggest a novel alteration in primary lung fibroblasts from IPF patients. The reduced Cx43 expression and the associated alteration in cell-to-cell communication may justify some of the known pathological characteristic of this devastating disease that still represents a challenge to the medical practice.
Trovato-Salinaro
Angela
A
Department of Chemical Sciences, Section of Biochemistry and Molecular Biology, University of Catania, Catania, Italy. A.salinaro@unict.it
Trovato-Salinaro
Elisa
E
Failla
Marco
M
Mastruzzo
Claudio
C
Tomaselli
Valerio
V
Gili
Elisa
E
Crimi
Nunzio
N
Condorelli
Daniele Filippo
DF
Vancheri
Carlo
C
D000222:Adaptation, Physiological; D002450:Cell Communication; D002478:Cells, Cultured; D018031:Connexin 43 / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism*; D017629:Gap Junctions / Q000378:metabolism*; D015870:Gene Expression; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008875:Middle Aged; D011658:Pulmonary Fibrosis / Q000503:physiopathology*
D018031:Connexin 43; C500216:GJA1 protein, human