Increased S100A4 expression in the vasculature of human COPD lungs and murine model of smoke-induced emphysema.
BACKGROUND
Chronic obstructive lung disease (COPD) is a common cause of death in industrialized countries often induced by exposure to tobacco smoke. A substantial number of patients with COPD also suffer from pulmonary hypertension that may be caused by hypoxia or other hypoxia-independent stimuli - inducing pulmonary vascular remodeling. The Ca(2+) binding protein, S100A4 is known to play a role in non-COPD-driven vascular remodeling of intrapulmonary arteries. Therefore, we have investigated the potential involvement of S100A4 in COPD induced vascular remodeling.


METHODS
Lung tissue was obtained from explanted lungs of five COPD patients and five non-transplanted donor lungs. Additionally, mice lungs of a tobacco-smoke-induced lung emphysema model (exposure for 3 and 8 month) and controls were investigated. Real-time RT-PCR analysis of S100A4 and RAGE mRNA was performed from laser-microdissected intrapulmonary arteries. S100A4 immunohistochemistry was semi-quantitatively evaluated. Mobility shift assay and siRNA knock-down were used to prove hypoxia responsive elements (HRE) and HIF binding within the S100A4 promoter.


RESULTS
Laser-microdissection in combination with real-time PCR analysis revealed higher expression of S100A4 mRNA in intrapulmonary arteries of COPD patients compared to donors. These findings were mirrored by semi-quantitative analysis of S100A4 immunostaining. Analogous to human lungs, in mice with tobacco-smoke-induced emphysema an up-regulation of S100A4 mRNA and protein was observed in intrapulmonary arteries. Putative HREs could be identified in the promoter region of the human S100A4 gene and their functionality was confirmed by mobility shift assay. Knock-down of HIF1/2 by siRNA attenuated hypoxia-dependent increase in S100A4 mRNA levels in human primary pulmonary artery smooth muscle cells. Interestingly, RAGE mRNA expression was enhanced in pulmonary arteries of tobacco-smoke exposed mice but not in pulmonary arteries of COPD patients.


CONCLUSIONS
As enhanced S100A4 expression was observed in remodeled intrapulmonary arteries of COPD patients, targeting S100A4 could serve as potential therapeutic option for prevention of vascular remodeling in COPD patients.
Excellence Cluster Cardio-Pulmonary System, Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany. se.reimann@asklepios.com.
Sebastian
S
Reimann
Excellence Cluster Cardio-Pulmonary System, Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany. Ludger.Fink@patho.med.uni-giessen.de.|Institute of Pathology and Cytology, UEGP, Forsthausstrasse 1, 35578, Wetzlar, Germany. Ludger.Fink@patho.med.uni-giessen.de.
Ludger
L
Fink
Excellence Cluster Cardio-Pulmonary System, Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany. Jochen.Wilhelm@patho.med.uni-giessen.de.
Jochen
J
Wilhelm
Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria. Julia.Hoffmann@lvr.lbg.ac.at.
Julia
J
Hoffmann
Excellence Cluster Cardio-Pulmonary System, Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany. Mariola.Bednorz@innere.med.uni-giessen.de.
Mariola
M
Bednorz
Excellence Cluster Cardio-Pulmonary System, Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany. Michael.Seimetz@innere.med.uni-giessen.de.
Michael
M
Seimetz
Excellence Cluster Cardio-Pulmonary System, Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany. Isabel.Laumanns@patho.med.uni-giessen.de.
Isabel
I
Dessureault
Excellence Cluster Cardio-Pulmonary System, Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany. Roger.Troesser@patho.med.uni-giessen.de.
Roger
R
Troesser
Department of Thoracic Surgery, Division of Surgery, Medical University Vienna, Vienna, Austria. Bahil.Ghanim@meduniwien.ac.at.
Bahil
B
Ghanim
Department of Thoracic Surgery, Division of Surgery, Medical University Vienna, Vienna, Austria. Walter.Klepetko@meduniwien.ac.at.
Walter
W
Klepetko
Excellence Cluster Cardio-Pulmonary System, Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany. Werner.Seeger@innere.med.uni-giessen.de.
Werner
W
Seeger
Excellence Cluster Cardio-Pulmonary System, Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany. Norbert.Weissmann@innere.med.uni-giessen.de.
Norbert
N
Weissmann
Excellence Cluster Cardio-Pulmonary System, Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany. Grazyna.Kwapiszewska@lvr.lbg.ac.at.|Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria. Grazyna.Kwapiszewska@lvr.lbg.ac.at.
Grazyna
G
Kwapiszewska
D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002478:Cells, Cultured; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D051793:Hypoxia-Inducible Factor 1 / Q000235:genetics / Q000378:metabolism; D008297:Male; D008810:Mice, Inbred C57BL; D008875:Middle Aged; D011651:Pulmonary Artery / Q000378:metabolism* / Q000473:pathology; D029424:Pulmonary Disease, Chronic Obstructive / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D011656:Pulmonary Emphysema / Q000209:etiology / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D034622:RNA Interference; D000067759:Receptor for Advanced Glycation End Products / Q000235:genetics / Q000378:metabolism; D020218:Response Elements; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins / Q000235:genetics / Q000378:metabolism*; D012907:Smoking / Q000009:adverse effects*; D014162:Transfection; D015854:Up-Regulation; D066253:Vascular Remodeling; D000099162:Endothelial PAS Domain-Containing Protein 1
D051792:Basic Helix-Loop-Helix Proteins; D051793:Hypoxia-Inducible Factor 1; D000067759:Receptor for Advanced Glycation End Products; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins; D000099162:Endothelial PAS Domain-Containing Protein 1; C000593871:AGER protein, human; C000593873:Ager protein, mouse; C470944:S100a4 protein, mouse; C077591:S100A4 protein, human