Proteinase activated receptor-2 counterbalances the vascular effects of endothelin-1 in fibrotic tight-skin mice.
OBJECTIVE
The majority of the severe vascular complications in fibrosis are a consequence of a deregulated activity of mediators controlling vasomotor tone. One of the most important of these mediators is endothelin-1 (ET-1). Here, we have investigated the role of proteinase-activated receptor 2 (PAR2) in the vascular dysfunction in a model of fibrosis, using tight-skin (Tsk) mice.


METHODS
Aortas were collected from Tsk, transgenic over-expressing PAR2 (TgPAR2), PAR2 deficient (PAR2-/-) or the corresponding WT mice. Histological and immunohistochemistry analysis for α-smooth muscle actin, PAR2 and ET-1 receptors were performed on aorta sections. Vascular responses to phenylephrine, ET-1 and PAR2 activating peptide (PAR2-AP) were assessed on aortic rings.


RESULTS
In aortas from Tsk mice, responses to phenylephrine were reduced, contractions to ET-1 were increased and vasorelaxation to PAR2-AP was enhanced. These alterations matched changes observed in whole vessel architecture such as vascular fibre re-organization, increased collagen deposition and enhanced α-smooth muscle actin expression. Expression of both ETAreceptors and PAR2 was enhanced in Tsk mice. Antagonism of PAR2 potentiated vascular effects of ET-1, whereas antagonism of ETAreceptors increased vasorelaxation induced by PAR2-AP. In TgPAR2 mice, responses to ET-1 and ET-1 plasma levels were reduced. Conversely, PAR2-/-mice showed enhanced ET-1 induced contraction in aortic rings and higher circulating ET-1 levels.


CONCLUSIONS
Our data show that PAR2 counterbalanced enhanced contractions to ET-1 in aortas from Tsk mice. PAR2 could represent a possible target for novel drugs in the treatment of vascular complications in fibrosis.


BACKGROUND
This article is part of a themed section on Targeting Inflammation to Reduce Cardiovascular Disease Risk. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.22/issuetoc and http://onlinelibrary.wiley.com/doi/10.1111/bcp.v82.4/issuetoc.
Department of Pharmacy, University of Napoli Federico II, Naples, Italy.
Fiorentina
F
Roviezzo
Department of Pharmacy, University of Napoli Federico II, Naples, Italy.|Department of Science, University of Basilicata, Potenza, Italy.
Vincenzo
V
Brancaleone
Department of Pharmacy, University of Napoli Federico II, Naples, Italy.
Valentina
V
Mattera Iacono
Department of Pharmacy, University of Napoli Federico II, Naples, Italy.
Antonio
A
Bertolino
Department of Life Science, University of Siena, Siena, Italy.
Giovanna
G
De Cunto
Department of Pharmacy, University of Napoli Federico II, Naples, Italy.
Valentina
V
Vellecco
Department of Life Science, University of Siena, Siena, Italy.
Giuseppe
G
Lungarella
Department of Life Science, University of Siena, Siena, Italy.
Monica
M
Lucattelli
Department of Pharmacy, University of Napoli Federico II, Naples, Italy.
Giuseppe
G
Cirino
D000818:Animals; D001013:Aorta, Thoracic / Q000378:metabolism / Q000473:pathology / Q000502:physiology*; D019332:Endothelin-1 / Q000097:blood / Q000502:physiology*; D005355:Fibrosis; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D044022:Receptor, Endothelin A / Q000378:metabolism / Q000502:physiology; D044464:Receptor, PAR-2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*
D019332:Endothelin-1; D044022:Receptor, Endothelin A; D044464:Receptor, PAR-2