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Altshuler AE, Lamadrid I, Li D, Ma SR, Kurre L, Schmid-Schönbein GW, Penn AH. Transmural intestinal wall permeability in severe ischemia after enteral protease inhibition. PLoS One 2014; 9:e96655. [PMID: 24805256 PMCID: PMC4013012 DOI: 10.1371/journal.pone.0096655] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 04/10/2014] [Indexed: 01/13/2023] Open
Abstract
In intestinal ischemia, inflammatory mediators in the small intestine's lumen such as food byproducts, bacteria, and digestive enzymes leak into the peritoneal space, lymph, and circulation, but the mechanisms by which the intestinal wall permeability initially increases are not well defined. We hypothesize that wall protease activity (independent of luminal proteases) and apoptosis contribute to the increased transmural permeability of the intestine's wall in an acutely ischemic small intestine. To model intestinal ischemia, the proximal jejunum to the distal ileum in the rat was excised, the lumen was rapidly flushed with saline to remove luminal contents, sectioned into equal length segments, and filled with a tracer (fluorescein) in saline, glucose, or protease inhibitors. The transmural fluorescein transport was determined over 2 hours. Villi structure and epithelial junctional proteins were analyzed. After ischemia, there was increased transmural permeability, loss of villi structure, and destruction of epithelial proteins. Supplementation with luminal glucose preserved the epithelium and significantly attenuated permeability and villi damage. Matrix metalloproteinase (MMP) inhibitors (doxycycline, GM 6001), and serine protease inhibitor (tranexamic acid) in the lumen, significantly reduced the fluorescein transport compared to saline for 90 min of ischemia. Based on these results, we tested in an in-vivo model of hemorrhagic shock (90 min 30 mmHg, 3 hours observation) for intestinal lesion formation. Single enteral interventions (saline, glucose, tranexamic acid) did not prevent intestinal lesions, while the combination of enteral glucose and tranexamic acid prevented lesion formation after hemorrhagic shock. The results suggest that apoptotic and protease mediated breakdown cause increased permeability and damage to the intestinal wall. Metabolic support in the lumen of an ischemic intestine with glucose reduces the transport from the lumen across the wall and enteral proteolytic inhibition attenuates tissue breakdown. These combined interventions ameliorate lesion formation in the small intestine after hemorrhagic shock.
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Affiliation(s)
- Angelina E. Altshuler
- Department of Bioengineering, The Institute of Engineering in Medicine, University Of California San Diego, La Jolla, California, United States of America
- * E-mail:
| | - Itze Lamadrid
- Department of Bioengineering, The Institute of Engineering in Medicine, University Of California San Diego, La Jolla, California, United States of America
| | - Diana Li
- Department of Bioengineering, The Institute of Engineering in Medicine, University Of California San Diego, La Jolla, California, United States of America
| | - Stephanie R. Ma
- Department of Bioengineering, The Institute of Engineering in Medicine, University Of California San Diego, La Jolla, California, United States of America
| | - Leena Kurre
- Department of Bioengineering, The Institute of Engineering in Medicine, University Of California San Diego, La Jolla, California, United States of America
| | - Geert W. Schmid-Schönbein
- Department of Bioengineering, The Institute of Engineering in Medicine, University Of California San Diego, La Jolla, California, United States of America
| | - Alexander H. Penn
- Department of Bioengineering, The Institute of Engineering in Medicine, University Of California San Diego, La Jolla, California, United States of America
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Altshuler AE, Richter MD, Modestino AE, Penn AH, Heller MJ, Schmid-Schönbein GW. Removal of luminal content protects the small intestine during hemorrhagic shock but is not sufficient to prevent lung injury. Physiol Rep 2013; 1:e00109. [PMID: 24303180 PMCID: PMC3841044 DOI: 10.1002/phy2.109] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 09/07/2013] [Accepted: 09/11/2013] [Indexed: 12/21/2022] Open
Abstract
The small intestine plays a key role in the pathogenesis of multiple organ failure following circulatory shock. Current results show that reduced perfusion of the small intestine compromises the mucosal epithelial barrier, and the intestinal contents (including pancreatic digestive enzymes and partially digested food) can enter the intestinal wall and transport through the circulation or mesenteric lymph to other organs such as the lung. The extent to which the luminal contents of the small intestine mediate tissue damage in the intestine and lung is poorly understood in shock. Therefore, rats were assigned to three groups: No-hemorrhagic shock (HS) control and HS with or without a flushed intestine. HS was induced by reducing the mean arterial pressure (30 mmHg; 90 min) followed by return of shed blood and observation (3 h). The small intestine and lung were analyzed for hemorrhage, neutrophil accumulation, and cellular membrane protein degradation. After HS, animals with luminal contents had increased neutrophil accumulation, bleeding, and destruction of E-cadherin in the intestine. Serine protease activity was elevated in mesenteric lymph fluid collected from a separate group of animals subjected to intestinal ischemia/reperfusion. Serine protease activity was elevated in the plasma after HS but was detected in lungs only in animals with nonflushed lumens. Despite removal of the luminal contents, lung injury occurred in both groups as determined by elevated neutrophil accumulation, permeability, and lung protein destruction. In conclusion, luminal contents significantly increase intestinal damage during experimental HS, suggesting transport of luminal contents across the intestinal wall should be minimized.
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Affiliation(s)
- Angelina E Altshuler
- Department of Bioengineering, The Institute of Engineering in Medicine, University of California San Diego La Jolla, California, 92093-0412
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Friese RS, Altshuler AE, Zhang K, Miramontes-Gonzalez JP, Hightower CM, Jirout ML, Salem RM, Gayen JR, Mahapatra NR, Biswas N, Cale M, Vaingankar SM, Kim HS, Courel M, Taupenot L, Ziegler MG, Schork NJ, Pravenec M, Mahata SK, Schmid-Schönbein GW, O'Connor DT. MicroRNA-22 and promoter motif polymorphisms at the Chga locus in genetic hypertension: functional and therapeutic implications for gene expression and the pathogenesis of hypertension. Hum Mol Genet 2013; 22:3624-40. [PMID: 23674521 DOI: 10.1093/hmg/ddt213] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Hypertension is a common hereditary syndrome with unclear pathogenesis. Chromogranin A (Chga), which catalyzes formation and cargo storage of regulated secretory granules in neuroendocrine cells, contributes to blood pressure homeostasis centrally and peripherally. Elevated Chga occurs in spontaneously hypertensive rat (SHR) adrenal glands and plasma, but central expression is unexplored. In this report, we measured SHR and Wistar-Kyoto rat (control) Chga expression in central and peripheral nervous systems, and found Chga protein to be decreased in the SHR brainstem, yet increased in the adrenal and the plasma. By re-sequencing, we systematically identified five promoter, two coding and one 3'-untranslated region (3'-UTR) polymorphism at the SHR (versus WKY or BN) Chga locus. Using HXB/BXH recombinant inbred (RI) strain linkage and correlations, we demonstrated genetic determination of Chga expression in SHR, including a cis-quantitative trait loci (QTLs) (i.e. at the Chga locus), and such expression influenced biochemical determinants of blood pressure, including a cascade of catecholamine biosynthetic enzymes, catecholamines themselves and steroids. Luciferase reporter assays demonstrated that the 3'-UTR polymorphism (which disrupts a microRNA miR-22 motif) and promoter polymorphisms altered gene expression consistent with the decline in SHR central Chga expression. Coding region polymorphisms did not account for changes in Chga expression or function. Thus, we hypothesized that the 3'-UTR and promoter mutations lead to dysregulation (diminution) of Chga in brainstem cardiovascular control nuclei, ultimately contributing to the pathogenesis of hypertension in SHR. Accordingly, we demonstrated that in vivo administration of miR-22 antagomir to SHR causes substantial (∼18 mmHg) reductions in blood pressure, opening a novel therapeutic avenue for hypertension.
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Affiliation(s)
- Ryan S Friese
- Department of Bioengineering, VA San Diego Healthcare System, University of California at San Diego, CA 92093, USA
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Mazor R, Alsaigh T, Shaked H, Altshuler AE, Pocock ES, Kistler EB, Karin M, Schmid-Schönbein GW. Matrix metalloproteinase-1-mediated up-regulation of vascular endothelial growth factor-2 in endothelial cells. J Biol Chem 2012; 288:598-607. [PMID: 23155052 DOI: 10.1074/jbc.m112.417451] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Matrix metalloproteinase-1 (MMP-1) is a collagenase that is highly active in extracellular matrix and vascular remodeling, angiogenesis, and tumor progression. Vascular endothelial growth factor receptor-2 (VEGFR2), the main receptor for VEGF-A, is expressed on endothelial cells and promotes cell survival, proliferation, and other functions. Although MMP-1 and VEGFR2 co-exist in many normal and pathophysiological conditions, the effect of MMP-1 on cellular VEGFR2 that can promote the above processes is unknown. In this study we test the hypothesis that stimulation of endothelial cells with MMP-1 increases their levels of VEGFR2. The increased VEGFR2 is then available to bind VEGF-A, resulting in increased response. Indeed we found that endothelial cells incubated with active MMP-1 had higher mRNA and protein levels of VEGFR2. Furthermore, VEGF-A-dependent phosphorylation of intracellular signaling molecules and endothelial proliferation were elevated after MMP-1 treatment. MMP-1 caused activation of the nuclear factor-κB (NF-κB) pathway (p65/RelA) in endothelial cells, and this response was dependent upon activation of protease activated receptor-1 (PAR-1). Chromatin immunoprecipitation was used to confirm NF-κB-mediated active transcription of the VEGFR2 (KDR) gene. Elevation in VEGFR2 after MMP-1 stimulation was inhibited by PAR-1 knockdown and NF-κB specific inhibition. We conclude that MMP-1 promotes VEGFR2 expression and proliferation of endothelial cells through stimulation of PAR-1 and activation of NF-κB. These results suggest a mechanism by which MMP-1 may prime or sensitize endothelial cell functions.
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Affiliation(s)
- Rafi Mazor
- Department of Bioengineering, The Institute of Engineering in Medicine, Veterans Affairs Medical Center, San Diego, California, USA.
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Altshuler AE, Penn AH, Yang J, Kim GR, Schmid-Schonbein GW. Trypsin and MMP‐9 Levels and Activity Increase in Plasma, Peritoneal Space, and Vital Organs during Hemorrhagic Shock. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.1132.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Jessica Yang
- BioengineeringUniversity of CaliforniaSan Diego, La JollaCA
| | - Ga-Ram Kim
- BioengineeringUniversity of CaliforniaSan Diego, La JollaCA
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Altshuler AE, Morgan MJ, Chien S, Schmid-Schönbein GW. Proteolytic Activity Attenuates the Response of Endothelial Cells to Fluid Shear Stress. Cell Mol Bioeng 2011; 5:82-91. [PMID: 22545072 DOI: 10.1007/s12195-011-0207-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022] Open
Abstract
Recent evidence indicates that several experimental pathophysiological conditions are associated with elevated protease activity in plasma, which impacts endothelial function. We hypothesize that extracellular structures bound to the endothelial cell (EC) membrane may be degraded by proteolytic activity and cause the cells to respond abnormally to physiological shear stress (12 dyn/cm(2)). To test this hypothesis, cultured bovine aortic endothelial cells (BAECs) were exposed to low levels of a serine protease, trypsin. Extracellular mechanosensor densities of the glycocalyx and vascular endothelial growth factor receptor 2 (VEGFR-2) were determined. Metabolic dysfunction was tested by examining insulin receptor and glucose uptake levels. Protease treatment impaired the cells' ability to align in the direction of fluid flow after 12 hours of shear stress; however, cells realigned after an additional 12 hours of shear stress with protease inhibition. Proteases caused reduction in the densities of glycocalyx, VEGFR-2, and insulin receptor in static and shear conditions, except for static VEGFR-2 cells. Under static conditions, protease-treated endothelial cells had reduced glucose uptake compared to untreated controls. Under shear, however, glucose uptake for protease-treated BAECs was greater than untreated controls. In conclusion, protease activity in plasma alters the exofacial membrane components of ECs and may interfere with mechanotransduction.
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Affiliation(s)
- Angelina E Altshuler
- Department of Bioengineering, The Institute of Engineering in Medicine, University Of California San Diego, La Jolla, California 92093-0412
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Yagodina LO, Altshuler AE, Abreimova YV. Preparation of spin-labeled bacterial ribonuclease from Bacillus intermedius 7P for EPR studies of protein dynamics. Biochemistry (Mosc) 1999; 64:957-61. [PMID: 10498815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
The optimal conditions for labeling of binase (a bacterial ribonuclease isolated from Bacillus intermedius 7P) with a bromoacetamide spin label have been determined. The label is suitable for probing the dynamics of the protein by electron paramagnetic resonance (EPR). Binase samples specifically labeled at residue His-101 of the active center were prepared by incubation for 48 h at 20 degrees C in potassium phosphate buffer (pH 5.5) containing the bromoacetamide (1:3 protein/label molar ratio). Fluorescence assay showed that the structure of the labeled binase is indistinguishable from that of the native protein.
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Affiliation(s)
- L O Yagodina
- Kazan Institute of Biochemistry and Biophysics, Kazan Research Center, Russian Academy of Sciences, Kazan, 420503, Russia.
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