Functional and phenotypical comparison of myofibroblasts derived from biopsies and bronchoalveolar lavage in mild asthma and scleroderma.
BACKGROUND
Activated fibroblasts, which have previously been obtained from bronchoalveolar lavage fluid (BALF), are proposed to be important cells in the fibrotic processes of asthma and scleroderma (SSc). We have studied the motility for BALF derived fibroblasts in patients with SSc that may explain the presence of these cells in the airway lumen. Furthermore, we have compared phenotypic alterations in activated fibroblasts from BALF and bronchial biopsies from patients with mild asthma and SSc that may account for the distinct fibrotic responses.


METHODS
Fibroblasts were cultured from BALF and bronchial biopsies from patients with mild asthma and SSc. The motility was studied using a cell migration assay. Western Blotting was used to study the expression of alpha-smooth muscle actin (alpha-SMA), ED-A fibronectin, and serine arginine splicing factor 20 (SRp20). The protein expression pattern was analyzed to reveal potential biomarkers using two-dimensional electrophoresis (2-DE) and sequencing dual matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-TOF). The Mann-Whitney method was used to calculate statistical significance.


RESULTS
Increased migration and levels of ED-A fibronectin were observed in BALF fibroblasts from both groups of patients, supported by increased expression of RhoA, Rac1, and the splicing factor SRp20. However, these observations were exclusively accompanied by increased expression of alpha-SMA in patients with mild asthma. Compared to BALF fibroblasts in mild asthma, fibroblasts in SSc displayed a differential protein expression pattern of cytoskeletal- and scavenger proteins. These identified proteins facilitate cell migration, oxidative stress, and the excessive deposition of extracellular matrix observed in patients with SSc.


CONCLUSIONS
This study demonstrates a possible origin for fibroblasts in the airway lumen in patients with SSc and important differences between fibroblast phenotypes in mild asthma and SSc. The findings may explain the distinct fibrotic processes and highlight the motile BALF fibroblast as a potential target cell in these disorders.
Larsen
Kristoffer
K
Experimental Medical Science, Division of Vascular and Airway Research, Lund University, S-221 84 Lund, Sweden. kristoffer.larsen@med.lu.se
Malmström
Johan
J
Wildt
Marie
M
Dahlqvist
Camilla
C
Hansson
Lennart
L
Marko-Varga
György
G
Bjermer
Leif
L
Scheja
Agneta
A
Westergren-Thorsson
Gunilla
G
D000328:Adult; D000368:Aged; D001249:Asthma / Q000235:genetics / Q000473:pathology / Q000503:physiopathology*; D001706:Biopsy; D001992:Bronchoalveolar Lavage Fluid; D002465:Cell Movement; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D032389:Myocytes, Smooth Muscle; D010641:Phenotype; D020543:Proteome / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism; D012595:Scleroderma, Systemic / Q000235:genetics / Q000473:pathology / Q000503:physiopathology*; D000068103:Serine-Arginine Splicing Factors; D016212:Transforming Growth Factor beta / Q000096:biosynthesis
D005353:Fibronectins; D020543:Proteome; D016601:RNA-Binding Proteins; C491388:SRSF3 protein, human; D016212:Transforming Growth Factor beta; D000068103:Serine-Arginine Splicing Factors; D020558:GTP Phosphohydrolases