title: Protective role of angiotensin II type 2 receptor signaling in a mouse model of pancreatic fibrosis.
abstract: The renin-angiotensin system contributes to pathological processes in a variety of organs. In the pancreas, blocking the angiotensin II (AII) type 1 receptor (AT1) attenuates pancreatic fibrogenesis in animal models of pancreatitis. Because the role of the AII type 2 receptor (AT2) in modulating pancreatic injury is unknown we investigated the role of AT2 in pancreatic injury and fibrosis. Pancreatic fibrosis was induced by repetitive cerulein administration in C57BL/6 wild-type (WT) or AT2-deficient (AT2-/-) mice and assessed by morphology and gene expression at 10 days. There was no difference between WT and AT2-/- mice in the degree of acute pancreatic injury as assessed by amylase release at 9 and 12 h and by histological examination of the pancreas at 12 h. In contrast, parenchymal atrophy and fibrosis were more pronounced in AT2-/- mice compared with WT mice at 10 days. Fibrosis was accompanied by activation of pancreatic stellate cells (PSC) evaluated by Western blot analysis for alpha-smooth muscle actin and by immunocytochemistry; PSC activation was further increased in AT2-/- mice compared with WT mice. The level of pancreatic transforming growth factor-beta1 mRNA and protein after repetitive cerulein treatment was higher in AT2-/- mice than in WT mice. Our results demonstrate that, in contrast to AT1 receptor signaling, AT2 receptor signaling modulates protective antifibrogenic effects in a mouse model of cerulein-induced pancreatic fibrogenesis. We propose that the effects of AII on injury-induced pancreatic fibrosis may be determined by the balance between AT1 and AT2 receptor signaling.
authors.affiliation: Department of Internal Medicine, Saint Louis University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Barbara
authors.initials: B
authors.lastname: Ulmasov
authors.forename: Zekuan
authors.initials: Z
authors.lastname: Xu
authors.forename: Laura H
authors.initials: LH
authors.lastname: Tetri
authors.forename: Tadashi
authors.initials: T
authors.lastname: Inagami
authors.forename: Brent A
authors.initials: BA
authors.lastname: Neuschwander-Tetri
mesh_terms: D000199:Actins / Q000378:metabolism; D000208:Acute Disease; D000681:Amylases / Q000097:blood; D000809:Angiotensins / Q000378:metabolism; D000818:Animals; D002108:Ceruletide; D003094:Collagen / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D005355:Fibrosis; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010179:Pancreas / Q000378:metabolism* / Q000473:pathology; D010195:Pancreatitis / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D012333:RNA, Messenger / Q000378:metabolism; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism; D044139:Receptor, Angiotensin, Type 2 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D012720:Severity of Illness Index; D015398:Signal Transduction; D013997:Time Factors; D053773:Transforming Growth Factor beta1 / Q000378:metabolism
chemical_list: D000199:Actins; D000809:Angiotensins; D012333:RNA, Messenger; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D053773:Transforming Growth Factor beta1; D002108:Ceruletide; D003094:Collagen; D000681:Amylases