Cellular phenotype transformation occurs during thoracic aortic aneurysm development.
OBJECTIVE
Thoracic aortic aneurysms result from dysregulated remodeling of the vascular extracellular matrix, which may occur as a result of altered resident cellular function. The present study tested the hypothesis that aortic fibroblasts undergo a stable change in cellular phenotype during thoracic aortic aneurysm formation.


METHODS
Primary murine aortic fibroblasts were isolated from normal and thoracic aortic aneurysm-induced aortas (4 weeks post induction with 0.5 mol/L CaCl(2) 15 minutes) by the outgrowth method. Normal and thoracic aortic aneurysm cultures were examined using a focused polymerase chain reaction array to determine fibroblast-specific changes in gene expression in the absence and presence of biological stimulation (endothelin-1, phorbol-12-myristate-13-acetate, angiotensin-II). The relative expression of 38 genes, normalized to 4 housekeeping genes, was determined, and genes displaying a minimum 2-fold increase/decrease or genes with significantly different normalized cycle threshold values were considered to have altered expression.


RESULTS
At steady state, thoracic aortic aneurysm fibroblasts revealed elevated expression of several matrix metalloproteinases (Mmp2, Mmp11, Mmp14), collagen genes/elastin (Col1a1, Col1a2, Col3a1, Eln), and other matrix proteins, as well as decreased expression of Mmp3, Timp3, and Ltbp1. Moreover, gene expression profiles in thoracic aortic aneurysm fibroblasts were different than normal fibroblasts after equivalent biological stimuli.


CONCLUSIONS
This study demonstrated for the first time that isolated primary aortic fibroblasts from thoracic aortic aneurysm-induced mice possess a unique and stable gene expression profile, and when challenged with biological stimuli, induce a transcriptional response that is different from normal aortic fibroblasts. Together, these data suggest that aortic fibroblasts undergo a stable phenotypic change during thoracic aortic aneurysm development, which may drive the enhancement of extracellular matrix proteolysis in thoracic aortic aneurysm progression.
Jones
Jeffrey A
JA
Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC 29425, USA. jonesja@musc.edu
Zavadzkas
Juozas A
JA
Chang
Eileen I
EI
Sheats
Nina
N
Koval
Christine
C
Stroud
Robert E
RE
Spinale
Francis G
FG
Ikonomidis
John S
JS
D000804:Angiotensin II / Q000378:metabolism; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D017545:Aortic Aneurysm, Thoracic / Q000139:chemically induced / Q000235:genetics* / Q000473:pathology; D002122:Calcium Chloride; D002478:Cells, Cultured; D004195:Disease Models, Animal; D018450:Disease Progression; D019332:Endothelin-1 / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D020869:Gene Expression Profiling / Q000379:methods; D005786:Gene Expression Regulation; D005838:Genotype; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010641:Phenotype; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D019332:Endothelin-1; D016326:Extracellular Matrix Proteins; D000804:Angiotensin II; D002122:Calcium Chloride; D013755:Tetradecanoylphorbol Acetate