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Aguilera-Lizarraga J, Ritoux A, Bulmer DC, Smith ESJ. Intestinal barrier function in the naked mole-rat: an emergent model for gastrointestinal insights. Am J Physiol Gastrointest Liver Physiol 2024; 327:G188-G201. [PMID: 38915279 DOI: 10.1152/ajpgi.00080.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 06/10/2024] [Accepted: 06/19/2024] [Indexed: 06/26/2024]
Abstract
The intestinal barrier plays a crucial role in homeostasis by both facilitating the absorption of nutrients and fluids and providing a tight shield to prevent the invasion by either pathogen or commensal microorganisms. Intestinal barrier malfunction is associated with systemic inflammation, oxidative stress, and decreased insulin sensitivity, which may lead to the dysregulation of other tissues. Therefore, a deeper understanding of physiological aspects related to an enhanced barrier function is of significant scientific and clinical relevance. The naked mole-rat has many unusual biological features, including attenuated colonic neuron sensitivity to acid and bradykinin and resistance to chemical-induced intestinal damage. However, insight into their intestinal barrier physiology is scarce. Here, we observed notable macroscopic and microscopic differences in intestinal tissue structure between naked mole-rats and mice. Moreover, naked mole-rats showed increased number of larger goblet cells and elevated mucus content. In measuring gut permeability, naked mole-rats showed reduced permeability compared with mice, measured as transepithelial electrical resistance, especially in ileum. Furthermore, intestinal ion secretion induced by serotonin, bradykinin, histamine, and capsaicin was significantly reduced in naked mole-rats compared with mice, despite the expression of receptors for all these agonists. In addition, naked mole-rats exhibited reduced prosecretory responses to the nonselective adenylate cyclase activator forskolin. Collectively, these findings indicate that naked mole-rats possess a robust and hard-to-penetrate gastrointestinal barrier that is resistant to environmental and endogenous irritants. Naked mole-rats may therefore provide valuable insights into the physiology of the intestinal barrier and set the stage for the development of innovative and effective therapies.NEW & NOTEWORTHY This is the first study to characterize the intestinal function of naked mole-rats. We found that these animals show a robust gut tissue structure, displaying thicker intestinal layers, longer villi, and larger crypts. Naked mole-rats showed more and larger goblet cells, with increased mucus content. Intestinal permeability, especially in the ileum, was substantially lower than that of mice. Finally, naked mole-rats showed reduced intestinal anion secretion in response to serotonin, bradykinin, histamine, capsaicin, and forskolin.
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Affiliation(s)
| | - Anne Ritoux
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - David C Bulmer
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Ewan St John Smith
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
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Didiasova M, Wujak L, Schaefer L, Wygrecka M. Factor XII in coagulation, inflammation and beyond. Cell Signal 2018; 51:257-265. [DOI: 10.1016/j.cellsig.2018.08.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 08/08/2018] [Accepted: 08/09/2018] [Indexed: 12/19/2022]
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Zamorano R, Suchindran S, Gainer JV. 3'-Untranslated region of the type 2 bradykinin receptor is a potent regulator of gene expression. Am J Physiol Renal Physiol 2005; 290:F456-64. [PMID: 16144969 DOI: 10.1152/ajprenal.00009.2005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Regulation of the constitutively expressed type 2 bradykinin (B2) receptor, which mediates the principal actions of bradykinin, occurs at multiple levels. The goal of the current study was to determine whether the human B2 3'-untranslated region (UTR) has effects on gene expression, with particular focus on the variable number of tandem repeats (B2-VNTR) polymorphic portion of the 3'-UTR and its flanking AU-rich elements (AREs). When inserted downstream of the luciferase coding region of the pGL3-Promoter vector, the B2-VNTR reduced reporter gene activity by 85% compared with pGL3-Promoter alone (promoter control; P < 0.001), an effect that was not appreciably affected by mutation of the flanking AREs. The negative regulatory effects of the B2-VNTR region were position and orientation dependent and strongly positively correlated with the number of tandem repeats in the B2-VNTR region (r = 0.85, P < 0.001). With respect to mechanism, quantitative RT-PCR revealed that the B2-VNTR mRNA level was 32% of that of promoter control (P = 0.008), whereas the number of polyadenylated transcripts was 4% (P = 0.02). In contrast, the mRNA half-life of the B2-VNTR was increased (B2-VNTR: 14.9 vs. promoter control: 12.2 h, P = 0.009). Transient transfection of human kidney-derived tsA201 cells with the B2-VNTR construct increased transcription of the native B2 receptor mRNA by 43% (P < 0.05), supporting an endogenous B2 receptor-regulatory capacity of the B2-VNTR. In conclusion, these results identify novel pretranslational effects of the B2-VNTR region to act as a potent negative regulator of heterologous gene expression and support the notion that the bradykinin B2 3'-UTR may impact endogenous receptor regulation.
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Affiliation(s)
- Rocio Zamorano
- Vanderbilt University Medical Center, Nashville, TN 37232-6602, USA
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4
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Stewen P, Outi S, Tuulikki N, Frej F. Cyclic AMP increases bradykinin receptor binding affinity in human endothelial cells. Life Sci 2004; 74:2839-52. [PMID: 15050422 DOI: 10.1016/j.lfs.2003.09.071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2003] [Accepted: 09/30/2003] [Indexed: 11/28/2022]
Abstract
We demonstrated bradykinin receptors in human endothelial cells and studied whether bradykinin receptors might be regulated by cyclic AMP. Messenger RNA for bradykinin B(1) and B(2) receptors was detected with real-time PCR and B(2) receptor protein was confirmed by immunoblotting. Saturation binding experiments with increasing concentrations of (125)I-[Tyr(8)]-bradykinin (25-700 pM) were made to determine maximal binding capacity and dissociation constant. However, saturation binding experiments suggested one class of binding sites, maximal binding capacity of 39.3 +/- 1.3 fmol/mg protein and dissociation constant of 352 +/- 27 pM. Competition studies with bradykinin B(1) and B(2) receptor antagonists showed that binding was competed by a B(1) antagonist, and when internalization was inhibited with hypertonic buffer, by both B(1) and B(2) antagonists. Stimulating cells with dibutyryl-cAMP, cholera toxin and forskolin for 24 h increased (125)I-[Tyr(8)]-bradykinin (90 pM) binding with approximately 50%. Saturation binding experiments with dibutyryl-cAMP stimulated cells showed, that the dissociation constant was altered from 352 +/- 27 pM in non-stimulated cells, to 203 +/- 18 pM (P < 0.001) in stimulated cells, while maximal binding capacity remained unchanged. Binding was competed similarly by the B(1) antagonist in stimulated and control cells. These results suggest, that the dibutyryl-cAMP stimulated increase in (125)I-[Tyr(8)]-bradykinin binding is probably due to increased B(1) receptor affinity with no change in receptor capacity. In conclusion, bradykinin B(1) and B(2) receptor mRNA was shown in human endothelial cells. Binding studies suggest that bradykinin receptors are competable with bradykinin antagonists. Adenylate cyclase activators probably increase bradykinin B(1) receptor affinity, without changing capacity, and thus increase bradykinin binding.
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MESH Headings
- Binding, Competitive
- Blotting, Western
- Bradykinin/analogs & derivatives
- Bradykinin/antagonists & inhibitors
- Bradykinin/metabolism
- Bradykinin B1 Receptor Antagonists
- Bradykinin B2 Receptor Antagonists
- Bucladesine/pharmacology
- Cells, Cultured
- Cholera Toxin/pharmacology
- Colforsin/pharmacology
- Dose-Response Relationship, Drug
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/pathology
- Humans
- RNA, Messenger/metabolism
- Receptor, Bradykinin B1/genetics
- Receptor, Bradykinin B1/metabolism
- Receptor, Bradykinin B2/genetics
- Receptor, Bradykinin B2/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Umbilical Veins/cytology
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Affiliation(s)
- Pia Stewen
- Minerva Institute for Medical Research, Helsinki, Finland.
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Holmes CL, Landry DW, Granton JT. Science Review: Vasopressin and the cardiovascular system part 2 - clinical physiology. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2003; 8:15-23. [PMID: 14975041 PMCID: PMC420051 DOI: 10.1186/cc2338] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Vasopressin is emerging as a rational therapy for vasodilatory shock states. In part 1 of the review we discussed the structure and function of the various vasopressin receptors. In part 2 we discuss vascular smooth muscle contraction pathways with an emphasis on the effects of vasopressin on ATP-sensitive K+ channels, nitric oxide pathways, and interaction with adrenergic agents. We explore the complex and contradictory studies of vasopressin on cardiac inotropy and coronary vascular tone. Finally, we summarize the clinical studies of vasopressin in shock states, which to date have been relatively small and have focused on physiologic outcomes. Because of potential adverse effects of vasopressin, clinical use of vasopressin in vasodilatory shock should await a randomized controlled trial of the effect of vasopressin's effect on outcomes such as organ failure and mortality.
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Affiliation(s)
- Cheryl L Holmes
- Staff intensivist, Department of Medicine, Division of Critical Care, Kelowna General Hospital, Kelowna BC, Canada
| | - Donald W Landry
- Associate Professor, Department of Medicine, Columbia University, New York, New York, USA
| | - John T Granton
- Assistant Professor of Medicine, Faculty of Medicine, and Program Director, Critical Care Medicine, University of Toronto, and Consultant in Pulmonary and Critical Care Medicine, Director Pulmonary Hypertension Program, University Health Network, Toronto, Ontario, Canada
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Phagoo SB, Yaqoob M, Herrera-Martinez E, McIntyre P, Jones C, Burgess GM. Regulation of bradykinin receptor gene expression in human lung fibroblasts. Eur J Pharmacol 2000; 397:237-46. [PMID: 10844120 DOI: 10.1016/s0014-2999(00)00323-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
In WI-38 human fibroblasts, interleukin-1 beta and tumour necrosis factor-alpha (TNF-alpha) increased bradykinin B(1) receptor mRNA, which peaked between 2 and 4 h, remaining elevated for 20 h. Binding of the bradykinin B(1) receptor selective ligand [3H]des-Arg(10)-kallidin, also increased, peaking at 4 h and remaining elevated for 20 h. The B(max) value for [3H]des-Arg(10)-kallidin rose from 280+/-102 fmol/mg (n=3) to 701+/-147 fmol/mg (n=3), but the K(D) value remained unaltered (control, 1.04+/-0.33 nM (n=3); interleukin-1 beta, 0.88+/-0.41 nM (n=3)). The interleukin-1 beta-induced [3H]des-Arg(10)-kallidin binding sites were functional receptors, as bradykinin B(1) receptor agonist-induced responses increased in treated cells. Bradykinin B(2) receptor mRNA and [3H]bradykinin binding were upregulated by interleukin-1 beta, but not TNF-alpha. The effect of interleukin-1 beta on bradykinin B(2) receptors was smaller than for bradykinin B(1) receptors. Cycloheximide prevented interleukin-1 beta-mediated increases in B(1) and B(2) binding, but not mRNA suggesting that de novo synthesis of a transcriptional activator was unnecessary.
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Affiliation(s)
- S B Phagoo
- Novartis Institute for Medical Sciences, 5 Gower Place, WC1E 6BN, London, UK
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Velarde V, Ullian ME, Morinelli TA, Mayfield RK, Jaffa AA. Mechanisms of MAPK activation by bradykinin in vascular smooth muscle cells. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:C253-61. [PMID: 10444401 DOI: 10.1152/ajpcell.1999.277.2.c253] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vascular smooth muscle cell (VSMC) proliferation is a prominent feature of the atherosclerotic process occurring after endothelial injury. A vascular wall kallikrein-kinin system has been described. The contribution of this system to vascular disease is undefined. In the present study we characterized the signal transduction pathway leading to mitogen-activated protein kinase (MAPK) activation in response to bradykinin (BK) in VSMC. Addition of 10(-10)-10(-7) M BK to VSMC resulted in a rapid and concentration-dependent increase in tyrosine phosphorylation of several 144- to 40-kDa proteins. This effect of BK was abolished by the B(2)-kinin receptor antagonist HOE-140, but not by the B(1)-kinin receptor antagonist des-Arg(9)-Leu(8)-BK. Immunoprecipitation with anti-phosphotyrosine antibodies followed by immunoblot revealed that 10(-9) M BK induced tyrosine phosphorylation of focal adhesion kinase (p125(FAK)). BK (10(-8) M) promoted the association of p60(src) with the adapter protein growth factor receptor binding protein-2 and also induced a significant increase in MAPK activity. Pertussis and cholera toxins did not inhibit BK-induced MAPK tyrosine phosphorylation. Protein kinase C downregulation by phorbol 12-myristate 13-acetate and/or inhibitors to protein kinase C, p60(src) kinase, and MAPK kinase inhibited BK-induced MAPK tyrosine phosphorylation. These findings provide evidence that activation of the B(2)-kinin receptor in VSMC leads to generation of multiple second messengers that converge to activate MAPK. The activation of this crucial kinase by BK provides a strong rationale to investigate the mitogenic actions of BK on VSMC proliferation in disease states of vascular injury.
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MESH Headings
- Animals
- Bradykinin/pharmacology
- Calcium-Calmodulin-Dependent Protein Kinases/drug effects
- Calcium-Calmodulin-Dependent Protein Kinases/metabolism
- Cells, Cultured
- Cholera Toxin/pharmacology
- Cytoplasm/enzymology
- Enzyme Activation/physiology
- Male
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Phosphorylation/drug effects
- Protein Kinase C/physiology
- Protein-Tyrosine Kinases/drug effects
- Protein-Tyrosine Kinases/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Bradykinin/physiology
- Tyrosine/metabolism
- Virulence Factors, Bordetella/pharmacology
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Affiliation(s)
- V Velarde
- Department of Medicine, Medical University of South Carolina and Ralph H. Johnson Department of Veterans Affairs Medical Center, Charleston, South Carolina 29425, USA
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Jin L, Chao L, Chao J. Potassium supplement upregulates the expression of renal kallikrein and bradykinin B2 receptor in SHR. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:F476-84. [PMID: 10070172 DOI: 10.1152/ajprenal.1999.276.3.f476] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
High potassium intake is known to attenuate hypertension, glomerular lesion, ischemic damage, and stroke-associated death. Our recent studies showed that expression of recombinant kallikrein by somatic gene delivery reduced high blood pressure, cardiac hypertrophy, and renal injury in hypertensive animal models. The aim of this study is to explore the potential role of the tissue kallikrein-kinin system in blood pressure reduction and renal protection in spontaneously hypertensive rats (SHR) on a high-potassium diet. Young SHR were given drinking water with or without 1% potassium chloride for 6 wk. Systolic blood pressure was significantly reduced beginning at 1 wk, and the effect lasted for 6 wk in the potassium-supplemented group compared with that in the control group. Potassium supplement induced 70 and 40% increases in urinary kallikrein levels and renal bradykinin B2 receptor density, respectively (P < 0.05), but did not change serum kininogen levels. Similarly, Northern blot analysis showed that renal kallikrein mRNA levels increased 2.7-fold, whereas hepatic kininogen mRNA levels remained unchanged in rats with high potassium intake. No difference was observed in beta-actin mRNA levels in the kidney or liver of either group. Competitive RT-PCR showed a 1.7-fold increase in renal bradykinin B2 receptor mRNA levels in rats with high potassium intake. Potassium supplement significantly increased water intake, urine excretion, urinary kinin, cAMP, and cGMP levels. This study suggests that upregulation of the tissue kallikrein-kinin system may be attributed, in part, to blood pressure-lowering and diuretic effects of high potassium intake.
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Affiliation(s)
- L Jin
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
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Lung CC, Jagels MA, Daffern PJ, Tan EM, Zuraw BL. Induction of human B2 bradykinin receptor mRNA and membrane receptors by IFNgamma. IMMUNOPHARMACOLOGY 1998; 39:243-53. [PMID: 9754910 DOI: 10.1016/s0162-3109(98)00008-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A potential mechanism for the increased sensitivity of inflamed tissues to bradykinin is the upregulation of bradykinin receptor expression. We report that recombinant human IFNgamma stimulated a concentration-dependent increase in cell surface bradykinin receptor expression in intact T24 human epithelial-like cells, determined by radioligand binding analysis. Analysis of specific [3H]-bradykinin binding revealed that IFNgamma-treated cells had a two- to threefold increase in bradykinin receptor number compared to the controls with no effect on receptor affinity. The ability of IFNgamma to stimulate increased bradykinin receptor expression was abrogated by treatment with either the transcription inhibitor actinomycin D or the protein synthesis inhibitor cycloheximide. IFNgamma enhanced steady-state human B2 bradykinin receptor mRNA expression in the T24 cells in a dose-dependent manner. B2 bradykinin receptor mRNA expression was increased as early as 1 h following IFNgamma stimulation, and continued to accumulate for 24 h. Bradykinin-stimulated intracellular calcium mobilization was also increased in IFNgamma-treated T24 cells compared to controls. The ability of IFNgamma to upregulate B2 bradykinin receptors in primary epithelial cells was demonstrated using cultured human airway epithelial cells. These observations suggest that increasing IFNgamma levels during inflammation may upregulate the expression of B2 bradykinin receptors, leading to increased sensitivity to bradykinin.
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Affiliation(s)
- C C Lung
- W.M. Keck Autoimmune Disease Center, Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
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10
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Marin Castaño ME, Schanstra JP, Hirtz C, Pesquero JB, Pecher C, Girolami JP, Bascands JL. B2 kinin receptor upregulation by cAMP is associated with BK-induced PGE2 production in rat mesangial cells. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:F532-40. [PMID: 9580144 DOI: 10.1152/ajprenal.1998.274.3.f532] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In the rat mesangial cell (MC), activation of the bradykinin B2 receptor (B2R) by bradykinin (BK) is associated with both phospholipase C (PLC) and A2 (PLA2) activities and with inhibition of adenosine 3',5'-cyclic monophosphate (cAMP) formation leading to cell contraction. Because cAMP plays an important role in the regulation of gene expression in general, we investigated the effect of increasing the intracellular cAMP concentration ([cAMP]i) in mesangial cells on the B2 mRNA expression, on the density of B2 receptor binding sites, on the BK-induced increase in both the free cytosolic Ca2+ concentration ([Ca2+]i), and in the prostaglandin E2 (PGE2) production. Forskolin, PGE2, and cAMP analog, 8-bromoadenosine 3',5'-cyclic monophosphate (8-BrcAMP), were used to increase [cAMP]i. Twenty-four-hour treatment with forskolin, PGE2, and 8-BrcAMP resulted in significant increases in B2 receptor binding sites, which were inhibited by cycloheximide. The maximum B2 receptor mRNA expression (160% above control) was observed in cells treated during 24 h with forskolin and was prevented by actinomycin D. In contrast, the D-myo-inositol 1,4,5-trisphosphate (IP3) formation and the BK-induced increase in [Ca2+]i, reflecting activation of PLC, were not affected by increased levels of [cAMP]i. However the BK-induced PGE2 release, reflecting PLA2 activity, was significantly enhanced. These data bring new information regarding the dual signaling pathways of B2 receptors that can be differentially regulated by cAMP.
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Affiliation(s)
- M E Marin Castaño
- Institut Louis Bugnard, Institut National de la Santé et de la Recherche Médicale U 388, Centre Hospitalier Universitaire Rangueil, Toulouse, France
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Costenbader K, Ardaillou N, Marchetti J, Placier S, Ardaillou R. Prostaglandin E2 enhances type 2-bradykinin receptor expression in human glomerular podocytes. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1358:142-52. [PMID: 9332450 DOI: 10.1016/s0167-4889(97)00069-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We examined the effect of prostaglandin E2 (PGE2) on bradykinin (BK) binding, BK-dependent intracellular calcium and inositol phosphate (i.p.) concentrations and BK mRNA in human glomerular visceral epithelial cells (hGVEC). PGE2 (10 nM) produced a concentration-dependent increase in [3H]-BK specific binding after a lag time of 24 h with a threshold at 0.1 nM. This increase appeared to be mediated exclusively by an increase in BK receptor (BKR)-2 expression. Scatchard analysis of [3H]-BK saturation binding showed that PGE2 produced an increase in the receptor site density without a change in the apparent dissociation constant. PGE2 also markedly stimulated cAMP production. This effect was thought to mediate the increase in expression of BKR-2 as 8-bromo cAMP and various cAMP-stimulating agents acted similarly. PGE2 did not change the BK-dependent intracellular IP3 and cytosolic calcium increases. The overexpression of BKR-2 in the presence of PGE2 was associated with an increase in mRNA as shown by the nuclease protection assay without any change in mRNA half-life. Cycloheximide, an inhibitor of protein synthesis, enhanced BKR-2 mRNA expression. In conclusion, treatment with PGE2 stimulates the synthesis of BKR-2 in hGVEC, possibly by interfering with an inhibitory protein involved in BKR-2 transcription.
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Chao J, Stallone JN, Liang YM, Chen LM, Wang DZ, Chao L. Kallistatin is a potent new vasodilator. J Clin Invest 1997; 100:11-7. [PMID: 9202051 PMCID: PMC508159 DOI: 10.1172/jci119502] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Kallistatin is a serine proteinase inhibitor which binds to tissue kallikrein and inhibits its activity. The aim of this study is to evaluate if kallistatin has a direct effect on the vasculature and on blood pressure homeostasis. We found that an intravenous bolus injection of human kallistatin caused a rapid, potent, and transient reduction of mean arterial blood pressure in anesthetized rats. Infusion of purified kallistatin (0.07-1.42 nmol/kg) into cannulated rat jugular vein produced a 20-85 mmHg reduction of blood pressure in a dose-dependent manner. Hoe 140, a bradykinin B2-receptor antagonist, had no effect on the hypotensive effect of kallistatin yet it abolished the blood pressure-lowering effect of kinin and kallikrein. Relaxation of isolated aortic rings by kallistatin was observed in the presence (ED50 of 3.4 x 10(-9) M) and in the absence of endothelium (ED50 of 10(-9) M). Rat kallikrein-binding protein, but not kinin or kallikrein, induced vascular relaxation of aortic rings. Neither Hoe 140 nor Nomega-nitro--arginine methyl ester, a nitric oxide synthase inhibitor, affected vasorelaxation induced by kallistatin. Kallistatin also caused dose-dependent vasodilation of the renal vasculature in the isolated, perfused rat kidney. Specific kallistatin-binding sites were identified in rat aorta by Scatchard plot analysis with a Kd of 0.25+/-0.07 nM and maximal binding capacity of 47.9+/-10.4 fmol/mg protein (mean+/-SEM, n = 3). These results indicate that kallistatin is a potent vasodilator which may function directly through a vascular smooth muscle mechanism independent of an endothelial bradykinin receptor. This study introduces the potential significance of kallistatin in directly regulating blood pressure to reduce hypertension.
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MESH Headings
- Adrenergic beta-Antagonists/pharmacology
- Animals
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/physiology
- Blood Pressure/drug effects
- Bradykinin/analogs & derivatives
- Bradykinin/pharmacology
- Carrier Proteins/administration & dosage
- Carrier Proteins/metabolism
- Carrier Proteins/pharmacology
- Humans
- In Vitro Techniques
- Infusions, Intravenous
- Injections, Intravenous
- Kallikreins/pharmacology
- Kinins/pharmacology
- Male
- Membrane Proteins/metabolism
- Muscle Contraction/drug effects
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- NG-Nitroarginine Methyl Ester/pharmacology
- Rats
- Rats, Inbred BN
- Rats, Inbred Strains
- Rats, Inbred WKY
- Rats, Sprague-Dawley
- Renal Circulation/drug effects
- Renal Circulation/physiology
- Serpins/administration & dosage
- Serpins/metabolism
- Serpins/pharmacology
- Vasodilation
- Vasodilator Agents
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Affiliation(s)
- J Chao
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
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Dixon BS, Sharma RV, Dennis MJ. The bradykinin B2 receptor is a delayed early response gene for platelet-derived growth factor in arterial smooth muscle cells. J Biol Chem 1996; 271:13324-32. [PMID: 8662783 DOI: 10.1074/jbc.271.23.13324] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Bradykinin and platelet-derived growth factor (PDGF) are inflammatory mediators important in the response to vascular injury. Based upon the known effect of oncogenic Ras to increase bradykinin receptor expression and the ability of PDGF to stimulate Ras, we examined whether PDGF regulates bradykinin B2 receptor expression in cultured arterial smooth muscle cells. Treatment with PDGF (AB and BB, but not AA) produced a dose- and time-dependent increase in both mRNA (6-7-fold increase at 2-4 h) and cell surface receptors (2-4-fold at 6-12 h) for the B2 receptor. There was a 60-min delay between exposure to PDGF and the initial increase in B2 receptor mRNA. Transcriptional inhibitors, actinomycin D or 5, 6-dichloro-1-beta-D-ribofuranosylbenzimidazole, completely blocked the increase in B2 receptor mRNA when added up to 60 min after stimulation with PDGF. However, protein synthesis was not required, as treatment with cycloheximide did not block but rather superinduced the PDGF-induced increase in B2 receptor mRNA. Comparison with the immediate early response gene c-fos demonstrated that the increase in B2 receptor mRNA was similarly inhibited by the tyrosine kinase inhibitor, tyrphostin, as well as staurosporine. However, stimulation of c-fos was slightly more sensitive to genistein, while the B2 receptor mRNA was more sensitive to inhibition by the protein kinase C inhibitor, calphostin C. The increase in cell surface B2 receptors were functionally coupled to an increase in phosphoinositide-specific phospholipase C, and the effects of PDGF were selective as there was no increase in either angiotensin II- or arginine vasopressin-induced inositol phosphate formation or intracellular calcium release. Taken together, these results demonstrate that the B2 receptor is a delayed early response gene for PDGF in vascular smooth muscle cells.
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MESH Headings
- Animals
- Base Sequence
- Bradykinin/pharmacology
- DNA Primers/genetics
- Enzyme Activation/drug effects
- Enzyme Inhibitors/pharmacology
- Gene Expression Regulation/drug effects
- Genes, fos
- Molecular Sequence Data
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Phosphatidylinositol Diacylglycerol-Lyase
- Phosphoric Diester Hydrolases/metabolism
- Platelet-Derived Growth Factor/pharmacology
- Protein Kinase C/antagonists & inhibitors
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Receptor, Bradykinin B2
- Receptors, Bradykinin/genetics
- Receptors, Bradykinin/metabolism
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Affiliation(s)
- B S Dixon
- Department of Medicine, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA
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14
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Pesquero JB, Lindsey CJ, Paiva AC, Ganten D, Bader M. Transcriptional regulatory elements in the rat bradykinin B2 receptor gene. IMMUNOPHARMACOLOGY 1996; 33:36-41. [PMID: 8856112 DOI: 10.1016/0162-3109(96)00080-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In an attempt to elucidate the mechanisms underlying the regulation of bradykinin B2 receptor gene expression, the molecular structure of the rat gene including the 5'-flanking region was characterized (J. Biol. Chem. 269: 26920-26925, 1994). In this study we show that the gene spans about 32 kb, including a long first intron of 25 kb. The promoter region drives reporter gene expression in NG108-15 neuroglioma cells, and its expression is upregulated by cAMP, bradykinin, phorbol esters and by coexpression of an activated ras oncogene but not by dexamethasone.
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Affiliation(s)
- J B Pesquero
- Department of Biophysics, Escola Paulista de Medicina, Säo Paulo, Brazil
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15
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Dixon BS, Dennis M. Interaction between growth factors and kinins in arterial smooth muscle cells. IMMUNOPHARMACOLOGY 1996; 33:16-23. [PMID: 8856109 DOI: 10.1016/0162-3109(96)00076-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Bradykinin receptors are present on vascular smooth muscle cells; however, the regulation and biological function of these receptors is unclear. To address these questions the interaction between growth factors and kinins in cultured arterial smooth muscle cells has been examined. Based upon the data a hypothesis is presented that platelet-derived growth factor (PDGF) upregulates cell surface bradykinin B2 receptors on arterial smooth muscle cells. The biological effect of the increase in B2 receptors is currently unclear but under certain conditions they may enhance mitogenesis. These mitogenic effects however, are strongly opposed by the effects of bradykinin acting via a B1-type of receptor which mediates potent inhibition of growth factor-induced mitogenesis.
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MESH Headings
- Animals
- Bradykinin/pharmacology
- Cell Division/drug effects
- Cells, Cultured
- Growth Substances/pharmacology
- Kinins/metabolism
- Kinins/pharmacology
- Models, Biological
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Platelet-Derived Growth Factor/pharmacology
- Rats
- Receptor, Bradykinin B2
- Receptors, Bradykinin/drug effects
- Receptors, Bradykinin/metabolism
- Up-Regulation
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Affiliation(s)
- B S Dixon
- Department of Medicine, University of Iowa College of Medicine, Iowa City, USA
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