Vascular endothelial growth factor expression in peritoneal mesothelial cells undergoing transdifferentiation.
OBJECTIVE
To analyze gene expression of localized peritoneal tissue structures in a rodent model of peritoneal fibrosis.


METHODS
Female Sprague Dawley rats were treated with an intraperitoneal injection of an adenovirus expressing active transforming growth factor-beta or control adenovirus. Four and 7 days after infection, animals were sacrificed and frozen sections of parietal peritoneum were subjected to immunofluorescence-aided laser capture microdissection in order to isolate vascular, mesothelial, and submesothelial structures. RNA was extracted from microdissected tissue and gene expression was analyzed by quantitative reverse-transcript polymerase chain reaction. We analyzed genes involved in angiogenesis, epithelial-to-mesenchymal transdifferentiation, and fibrosis. Vascular endothelial growth factor and alpha-smooth muscle actin expression was analyzed with immunohistochemistry of formalin-fixed tissue.


RESULTS
Transforming growth factor-beta(1) induced expression of Snail and alpha-smooth muscle actin genes in the peritoneal mesothelium. This same cell population also demonstrated increased gene expression of vascular endothelial growth factor. The distribution of this growth factor was confirmed by immunohistochemistry. The fibrogenic growth factor, connective tissue growth factor, was also strongly induced in the peritoneal mesothelium.


CONCLUSIONS
Using immunofluorescence-aided laser capture microdissection, we were able to study gene expression in subcompartments of the peritoneal tissue. We demonstrated that mesothelial cells exhibiting mesenchymal transdifferentiation are associated with increased expression of genes associated with fibrosis and angiogenesis.
Zhang
Jing
J
Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
Oh
Kook-Hwan
KH
Xu
Hui
H
Margetts
Peter J
PJ
D000199:Actins / Q000378:metabolism; D042702:Angiopoietin-2 / Q000378:metabolism; D000818:Animals; D054338:Cell Transdifferentiation; D055513:Connective Tissue Growth Factor / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology* / Q000378:metabolism*; D005260:Female; D015870:Gene Expression; D047569:Laser Scanning Cytometry; D042282:Microdissection; D010537:Peritoneum / Q000166:cytology* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
D000199:Actins; D042702:Angiopoietin-2; D055513:Connective Tissue Growth Factor; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D042461:Vascular Endothelial Growth Factor A; C000604450:Snai2 protein, rat; C498862:Acta2 protein, rat