Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.23.15 (renin)
 35,795 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The renin-angiotensin system (RAS) plays important roles in various pathophysiological processes. However, the role of the RAS in pancreatic fibrosis has not been established. We investigated the role of angiotensin II (ANG II)-ANG II type 1 (AT(1)) receptor pathway in the development of pancreatic fibrosis with AT(1a) receptor-deficient [AT(1a)(-/-)] mice. To induce pancreatic fibrosis, AT(1a)(-/-) and wild-type (WT) mice were submitted to three episodes of acute pancreatitis induced by six intraperitoneal injections of 50 microg/kg body wt cerulein at hourly intervals, per week, for four consecutive weeks. Pancreatic fibrosis was assessed by histology and hydroxyproline content. Pancreatic stellate cell (PSC) activation and the localization of AT(1) receptors were assessed by Western blot analysis for alpha-smooth muscle actin and immunostaining. Transforming growth factor-beta(1) (TGF-beta(1)) mRNA expression in the pancreas was assessed by RT-PCR. Six intraperitoneal injections of cerulein induced acute pancreatitis in both AT(1a)(-/-) and WT mice. There were no significant differences between two groups with regard to serum amylase and histological changes. Pancreatic fibrosis induced by repeated episodes of acute pancreatitis was significantly attenuated in AT(1a)(-/-) mice compared with that in WT mice. This finding was accompanied by a reduction of activated PSCs. Dual-immunofluorescence staining in WT mice revealed that activated PSCs express AT(1) receptors. The level of TGF-beta(1) mRNA was lower in AT(1a)(-/-) mice than in WT mice. Our results demonstrate that the ANG II-AT(1) receptor pathway is not essential for the local pancreatic injury in acute pancreatitis but plays an important role in the development of pancreatic fibrosis through PSC activation and proliferation.
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PMID:Angiotensin II type 1 receptor interaction is an important regulator for the development of pancreatic fibrosis in mice. 1501 12

Pancreatic stellate cells (PSCs) play a crucial role in pancreatic fibrogenesis in chronic pancreatitis and in the desmoplastic reaction of pancreatic cancer. When PSCs are stimulated by oxidative stress, ethanol and its metabolite acetaldehyde, and cytokines, the phenotype of quiescent fat-storing cells converts to myofibroblastlike activated PSCs, which then produce extracellular matrix, adhesion molecules, and various chemokines in response to cytokines and growth factors. Recent data suggest that PSCs have a phagocytic function. Plateletderived growth factor is a potent stimulator of PSC proliferation. Transforming growth factor beta, activin A, and connective tissue growth factor also play a role in PSC-mediated pancreatic fibrogenesis through autocrine and paracrine loops. Following pancreatic damage, pathophysiological processes that occur in the pancreas, including pancreas tissue pressure, hyperglycemia, intracellular reactive oxygen species production, activation of protease-activated receptor 2, induction of cyclooxygenase 2, and bacterial infection play a role in sustaining pancreatic fibrosis through increased PSC proliferation and collagen production by PSCs. Targeting PSCs might be an effective therapeutic approach in chronic pancreatitis. Various substances including vitamin A, vitamin E, polyphenols, peroxisome proliferator-activated receptor gamma ligands, and inhibitors of the renin-angiotensin system show great promise of being useful in the treatment of chronic pancreatitis.
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PMID:Mechanisms of pancreatic fibrosis and applications to the treatment of chronic pancreatitis. 1901 35

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.
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PMID:Protective role of angiotensin II type 2 receptor signaling in a mouse model of pancreatic fibrosis. 1903 39