The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform

Christopher V Carman - One of the best experts on this subject based on the ideXlab platform.

  • probing the biomechanical contribution of the endothelium to lymphocyte migration Diapedesis by the path of least resistance
    Journal of Cell Science, 2014
    Co-Authors: Roberta Martinelli, Tracey E Sciuto, Ann M Dvorak, Adam S Zeiger, Matthew J Whitfield, Krystyn J Van Vliet, J Greenwood, Christopher V Carman
    Abstract:

    Immune cell trafficking requires the frequent breaching of the endothelial barrier either directly through individual cells (‘transcellular’ route) or through the inter-endothelial junctions (‘paracellular’ route). What determines the loci or route of breaching events is an open question with important implications for overall barrier regulation. We hypothesized that basic biomechanical properties of the endothelium might serve as crucial determinants of this process. By altering junctional integrity, cytoskeletal morphology and, consequently, local endothelial cell stiffness of different vascular beds, we could modify the preferred route of Diapedesis. In particular, high barrier function was associated with predominantly transcellular migration, whereas negative modulation of junctional integrity resulted in a switch to paracellular Diapedesis. Furthermore, we showed that lymphocytes dynamically probe the underlying endothelium by extending invadosome-like protrusions (ILPs) into its surface that deform the nuclear lamina, distort actin filaments and ultimately breach the barrier. Fluorescence imaging and pharmacologic depletion of F-actin demonstrated that lymphocyte barrier breaching efficiency was inversely correlated with local endothelial F-actin density and stiffness. Taken together, these data support the hypothesis that lymphocytes are guided by the mechanical ‘path of least resistance’ as they transverse the endothelium, a process we term ‘tenertaxis’.

  • new observations on the trafficking and Diapedesis of monocytes
    Current Opinion in Hematology, 2010
    Co-Authors: Masataka Kamei, Christopher V Carman
    Abstract:

    Purpose of reviewMonocytes play multiple roles in immune system functions and inflammatory diseases such as atherosclerosis. These roles are coupled to diverse trafficking and cellular migration behaviors. Here, we review recent advances in our understanding of such behaviors with emphasis on broad

  • mechanisms for transcellular Diapedesis probing and pathfinding by invadosome like protrusions
    Journal of Cell Science, 2009
    Co-Authors: Christopher V Carman
    Abstract:

    Immune-system functions require that blood leukocytes continuously traffic throughout the body and repeatedly cross endothelial barriers (i.e. diapedese) as they enter (intravasate) and exit (extravasate) the circulation. The very earliest studies to characterize Diapedesis directly in vivo suggested the coexistence of two distinct migratory pathways of leukocytes: between (paracellular pathway) and directly through (transcellular pathway) individual endothelial cells. In vivo studies over the past 50 years have demonstrated significant use of the transcellular Diapedesis pathway in bone marrow, thymus, secondary lymphoid organs, various lymphatic structures and peripheral tissues during inflammation and across the blood-brain barrier and blood-retinal barrier during inflammatory pathology. Recently, the first in vitro reports of transcellular Diapedesis have emerged. Together, these in vitro and in vivo observations suggest a model of migratory pathfinding in which dynamic `invadosome-like protrusions9 formed by leukocytes have a central role in both identifying and exploiting endothelial locations that are permissive for transcellular Diapedesis. Such `probing9 activity might have additional roles in this and other settings.

  • settings and mechanisms for trans cellular Diapedesis
    Frontiers in Bioscience, 2009
    Co-Authors: Peter T Sage, Christopher V Carman
    Abstract:

    : Immune system functions require blood leukocytes to continuously traffic throughout the body and repeatedly cross endothelial barriers (i.e., diapedese) as they enter (intravasation) and exit (extravasation) the circulation. The earliest studies to directly characterize Diapedesis in vivo suggested co-existence of two distinct migratory pathways: between (para-cellular) and through (trans-cellular) individual endothelial cells. However, in the absence of conclusive in vitro observations, the latter pathway remained poorly accepted. The recent emergence of unambiguous in vitro reports of trans-cellular Diapedesis has begun to illuminate mechanisms for this pathway and has renewed interest in its physiological roles. A thorough reevaluation of the existing literature reveals a large number of studies documenting significant use of the trans-cellular pathway in diverse in vivo settings. These include constitutive trafficking in bone marrow and lymphoid organs as well as upregulated extravasation in peripheral tissues during inflammation. Here we collectively summarize these in vivo observations alongside the emerging in vitro data in order to provide a framework for understanding the settings, mechanisms and roles for the trans-cellular route of Diapedesis.

  • chapter 10 transmigratory cups and invadosome like protrusions new aspects of Diapedesis
    Current Topics in Membranes, 2009
    Co-Authors: Christopher V Carman
    Abstract:

    Publisher Summary Immune cell (i.e., blood leukocyte) functions are strongly coupled to their ability to traffic throughout the body as they conduct immune surveillance and respond to pathogens. Central aspects of this trafficking are the continuous transitions from the tissue into the blood circulation and vice versa. The vascular endothelium represents the interface between these two tissue compartments, serving as both a barrier to leukocyte trafficking and a sentinel to instruct leukocyte adhesion, transmigration, and activation behaviors. The activation state and barrier properties of endothelium are also, in turn, strongly influenced by leukocytes. Thus, leukocyte–endothelial interactions represent a critical nexus for information exchange with strong implications for vascular and immune cell activities, particularly during immune and inflammatory responses. Basic mechanisms by which these interactions facilitate leukocyte trafficking and intercellular communication are, therefore, of central biomedical significance. Building on the classic three-step adhesion/activation cascade, recent studies have begun to reveal new and complex behaviors associated with leukocyte–endothelial interactions suggesting existence of highly dynamic and bidirectional proactive responses in both of these cell types. The chapter illustrates these ideas by two very recently emerging activities/structures, namely, transmigratory cups formed by endothelium and invadosome-like protrusions (ILP) formed by leukocytes. The chapter discusses the basic in vivo and in vitro observation of these structures, their molecular composition/regulation, and functional roles.

William A Muller - One of the best experts on this subject based on the ideXlab platform.

  • pecam 1 stabilizes blood brain barrier integrity and favors paracellular t cell Diapedesis across the blood brain barrier during neuroinflammation
    Frontiers in Immunology, 2019
    Co-Authors: William A Muller, Urban Deutsch, Ruth Lyck, Isabella Wimmer, Silvia Tietz, Hideaki Nishihara, Federica Sallusto, Fabien Gosselet, Hans Lassmann
    Abstract:

    Breakdown of the blood-brain barrier (BBB) and increased immune cell trafficking into the central nervous system (CNS) are hallmarks of the pathogenesis of multiple sclerosis (MS). Platelet endothelial cell adhesion molecule-1 (PECAM-1; CD31) is expressed on cells of the vascular compartment and regulates vascular integrity and immune cell trafficking. Involvement of PECAM-1 in MS pathogenesis has been suggested by the detection of increased levels of soluble PECAM-1 (sPECAM-1) in the serum and CSF of MS patients. Here, we report profound upregulation of cell-bound PECAM-1 in initial (pre-phagocytic) white matter as well as active cortical gray matter MS lesions. Using a human in vitro BBB model we observed that PECAM-1 is not essential for the transmigration of human CD4+ T-cell subsets (Th1, Th1*, Th2, and Th17) across the BBB. Employing an additional in vitro BBB model based on primary mouse brain microvascular endothelial cells (pMBMECs) we show that the lack of endothelial PECAM-1 impairs BBB properties as shown by reduced transendothelial electrical resistance (TEER) and increases permeability for small molecular tracers. Investigating T-cell migration across the BBB under physiological flow by in vitro live cell imaging revealed that absence of PECAM-1 in pMBMECs did not influence arrest, polarization, and crawling of effector/memory CD4+ T cells on the pMBMECs. Absence of endothelial PECAM-1 also did not affect the number of T cells able to cross the pMBMEC monolayer under flow, but surprisingly favored transcellular over paracellular T-cell Diapedesis. Taken together, our data demonstrate that PECAM-1 is critically involved in regulating BBB permeability and although not required for T-cell Diapedesis itself, its presence or absence influences the cellular route of T-cell Diapedesis across the BBB. Upregulated expression of cell-bound PECAM-1 in human MS lesions may thus reflect vascular repair mechanisms aiming to restore BBB integrity and paracellular T-cell migration across the BBB as it occurs during CNS immune surveillance.

  • rapid remodeling of tight junctions during paracellular Diapedesis in a human model of the blood brain barrier
    Journal of Immunology, 2014
    Co-Authors: Ryan C Winger, Jennifer E Koblinski, Takashi Kanda, Richard M Ransohoff, William A Muller
    Abstract:

    Leukocyte transendothelial migration (TEM; Diapedesis) is a critical event in immune surveillance and inflammation. Most TEM occurs at endothelial cell borders (paracellular). However, there is indirect evidence to suggest that, at the tight junctions of the blood–brain barrier (BBB), leukocytes migrate directly through the endothelial cell body (transcellular). Why leukocytes migrate through the endothelial cell body rather than the cell borders is unknown. To test the hypothesis that the tightness of endothelial cell junctions influences the pathway of Diapedesis, we developed an in vitro model of the BBB that possessed 10-fold higher electrical resistance than standard culture conditions and strongly expressed the BBB tight junction proteins claudin-5 and claudin-3. We found that paracellular TEM was still the predominant pathway (≥98%) and TEM was dependent on PECAM-1 and CD99. We show that endothelial tight junctions expressing claudin-5 are dynamic and undergo rapid remodeling during TEM. Membrane from the endothelial lateral border recycling compartment is mobilized to the exact site of tight junction remodeling. This preserves the endothelial barrier by sealing the intercellular gaps with membrane and engaging the migrating leukocyte with unligated adhesion molecules (PECAM-1 and CD99) as it crosses the cell border. These findings provide new insights into leukocyte–endothelial interactions at the BBB and suggest that tight junctions are more dynamic than previously appreciated.

  • Rapid Remodeling of Tight Junctions during Paracellular Diapedesis in a Human Model of the Blood–Brain Barrier
    Journal of Immunology, 2014
    Co-Authors: Ryan C Winger, Jennifer E Koblinski, Takashi Kanda, Richard M Ransohoff, William A Muller
    Abstract:

    Leukocyte transendothelial migration (TEM; Diapedesis) is a critical event in immune surveillance and inflammation. Most TEM occurs at endothelial cell borders (paracellular). However, there is indirect evidence to suggest that, at the tight junctions of the blood–brain barrier (BBB), leukocytes migrate directly through the endothelial cell body (transcellular). Why leukocytes migrate through the endothelial cell body rather than the cell borders is unknown. To test the hypothesis that the tightness of endothelial cell junctions influences the pathway of Diapedesis, we developed an in vitro model of the BBB that possessed 10-fold higher electrical resistance than standard culture conditions and strongly expressed the BBB tight junction proteins claudin-5 and claudin-3. We found that paracellular TEM was still the predominant pathway (≥98%) and TEM was dependent on PECAM-1 and CD99. We show that endothelial tight junctions expressing claudin-5 are dynamic and undergo rapid remodeling during TEM. Membrane from the endothelial lateral border recycling compartment is mobilized to the exact site of tight junction remodeling. This preserves the endothelial barrier by sealing the intercellular gaps with membrane and engaging the migrating leukocyte with unligated adhesion molecules (PECAM-1 and CD99) as it crosses the cell border. These findings provide new insights into leukocyte–endothelial interactions at the BBB and suggest that tight junctions are more dynamic than previously appreciated.

  • endothelial src kinase regulates membrane recycling from the lateral border recycling compartment during leukocyte transendothelial migration
    European Journal of Immunology, 2008
    Co-Authors: Bidisha Dasgupta, William A Muller
    Abstract:

    When leukocytes cross endothelial cells during the inflammatory response, membrane from the recently described lateral border recycling compartment (LBRC) is selectively targeted around diapedesing leukocytes. This “targeted recycling” is critical for leukocyte transendothelial migration. Blocking homophilic PECAM interactions between leukocytes and endothelial cells blocks targeted recycling from the LBRC and blocks Diapedesis. However, the cellular signaling pathways that trigger targeted recycling are not known. We show that targeted recycling from the LBRC is dependent on Src kinase. The selective Src kinase inhibitor PP2 blocked targeted recycling and blocked Diapedesis by over 70%. However, Src kinase inhibition did not affect the structure or normal constitutive recycling of membrane from the LBRC in the absence of leukocytes. PECAM, a Src kinase substrate, traffics between the LBRC and the endothelial surface at the cell border. However, virtually all of the PECAM in the cell that was phosphorylated on tyrosine residues was found in the LBRC. These findings demonstrate that Src kinase activity is critical for the targeted recycling of membrane from the LBRC to the site of transendothelial migration and that the PECAM in the LBRC is qualitatively different from the PECAM on the surface of endothelial cells.

  • cd99 is essential for leukocyte Diapedesis in vivo
    Cell Communication and Adhesion, 2008
    Co-Authors: Eric M Dufour, Alana Deroche, William A Muller
    Abstract:

    Recruitment of leukocytes into inflamed tissue requires migration of leukocytes from the blood stream across the endothelial lining and the basement membrane of the local blood vessels. CD99 in humans is a 32-kDa highly O-glycosylated cell surface protein expressed on most leukocytes. The authors recently found CD99 to be expressed in leukocytes and at human endothelial cell contacts. Human CD99 is involved in homophilic interaction between the two cell types and participates in the transendothelial migration of monocytes and polymorphonuclear neutrophils (PMNs) in vitro. To test the role of CD99 in vivo, the authors cloned murine CD99 (muCD99), expressed it in vitro, and generated a blocking monoclonal antibody against it. We first showed that muCD99 is expressed on mouse leukocytes as well as enriched at the endothelial cell borders. Transfection of cells with muCD99 imparts on them the ability to aggregate in a CD99-dependent homophilic manner. Cells expressing muCD99 did not bind to cells expressing m...

Martin Sandig - One of the best experts on this subject based on the ideXlab platform.

  • the p110δ isoform of pi3k differentially regulates β1 and β2 integrin mediated monocyte adhesion and spreading and modulates Diapedesis
    Microcirculation, 2006
    Co-Authors: Alexander M Ferreira, Kem A Rogers, Harold Isaacs, Joel S Hayflick, Martin Sandig
    Abstract:

    Objective: Leukocyte Diapedesis is misregulated in inflammatory disease and depends on the binding of monocytic LFA-1 and VLA-4 to endothelial ICAM-1 and VCAM-1, respectively. The authors hypothesized that these different molecular interactions elicit specific signaling cascades within monocytes regulating specific steps in adhesion, motility, and Diapedesis.Methods: The authors employed the PI3K p110δ catalytic subunit specific inhibitor IC87114 (2 μ M) and the broad-spectrum PI3K inhibitory agents LY294002 (50 μ M) and wortmannin (100 nM), to examine the role of PI3Kδ in monocyte Diapedesis through endothelial monolayers and its role in monocyte adhesion and spreading upon carpets of ICAM-1 or VCAM-1. They further explored the effects of PI3Kδ inhibition on the activation state of β 1 and β 2 integrins with immunocytochemistry and flow cytometry.Results: In human peripheral blood monocytes IC87114 was as effective as wortmannin and LY294002 at inhibiting Diapedesis, however, in THP-1 cells LY294002 and ...

  • interleukin 1β reduces transcellular monocyte Diapedesis and compromises endothelial adherens junction integrity
    Microcirculation, 2005
    Co-Authors: Alexander M Ferreira, Ceara Mcneil, Karen M Stallaert, Kem A Rogers, Martin Sandig
    Abstract:

    Objective: Diapedesis occurs through endothelial cell–cell junctions (paracellular) or through individual endothelial cells without disrupting junctions (transcellular). While in vitro studies have provided considerable insight into mechanisms controlling paracellular Diapedesis, little is known about what regulates transcellular Diapedesis. The authors investigated whether transcellular Diapedesis is susceptible to IL-1β exposure of the endothelium.Methods: Laser scanning confocal microscopy and biochemical analysis were used to determine the effect of IL-1β pretreatment of the endothelium on adherens junctional morphology and monocyte transcellular Diapedesis in cocultures of human peripheral blood monocytes and coronary artery endothelial cells.Results: IL-1β pretreatment caused a 40% decrease in the number of migrating monocytes that used a transcellular route of Diapedesis, and resulted in elongate endothelial cell morphology, a reorganization of the F-actin cytoskeleton, and a significant decrease i...

  • Interleukin‐1β Reduces Transcellular Monocyte Diapedesis and Compromises Endothelial Adherens Junction Integrity
    Microcirculation, 2005
    Co-Authors: Alexander M Ferreira, Karen M Stallaert, Kem A Rogers, Ceara J. Mcneil, Martin Sandig
    Abstract:

    Objective: Diapedesis occurs through endothelial cell–cell junctions (paracellular) or through individual endothelial cells without disrupting junctions (transcellular). While in vitro studies have provided considerable insight into mechanisms controlling paracellular Diapedesis, little is known about what regulates transcellular Diapedesis. The authors investigated whether transcellular Diapedesis is susceptible to IL-1β exposure of the endothelium.Methods: Laser scanning confocal microscopy and biochemical analysis were used to determine the effect of IL-1β pretreatment of the endothelium on adherens junctional morphology and monocyte transcellular Diapedesis in cocultures of human peripheral blood monocytes and coronary artery endothelial cells.Results: IL-1β pretreatment caused a 40% decrease in the number of migrating monocytes that used a transcellular route of Diapedesis, and resulted in elongate endothelial cell morphology, a reorganization of the F-actin cytoskeleton, and a significant decrease i...

  • connexin 43 mediated gap junctional communication enhances breast tumor cell Diapedesis in culture
    Breast Cancer Research, 2005
    Co-Authors: Maryann Pollmann, Qing Shao, Dale W Laird, Martin Sandig
    Abstract:

    Introduction Metastasis involves the emigration of tumor cells through the vascular endothelium, a process also known as Diapedesis. The molecular mechanisms regulating tumor cell Diapedesis are poorly understood, but may involve heterocellular gap junctional intercellular communication (GJIC) between tumor cells and endothelial cells.

  • neutrophil Diapedesis paracellular or transcellular
    Physiology, 2001
    Co-Authors: Peter R Kvietys, Martin Sandig
    Abstract:

    To reach an inflammatory site in the interstitium, circulating neutrophils (PMN) must first traverse the endothelial barrier. Whether PMN emigrate between endothelial cells (paracellular pathway) or through the endothelial cells proper (transcellular pathway) is controversial. Herein, we present anatomic, functional, and teleological arguments that support both points of view. An attempt is also made to reconcile this apparent controversy.

Herbert B Hechtman - One of the best experts on this subject based on the ideXlab platform.

  • lavage with leukotriene b4 induces lung generation of tumor necrosis factor alpha that in turn mediates neutrophil Diapedesis
    Surgery, 1993
    Co-Authors: G Goldman, Richard Welbourn, C R Valeri, David Shepro, Lester Kobzik, Herbert B Hechtman
    Abstract:

    : In experimental models of acute respiratory failure, leukotriene (LT) B4 is generated in the lungs, followed by a 2- to 3-hour delay before there is substantial neutrophil (PMN) accumulation and increased permeability. This study tests whether lavage with LTB4 induces tumor necrosis factor (TNF) synthesis by the lungs that in turn mediates PMN Diapedesis. Anesthetized rats underwent lavage with 0.1 ml LTB4 (10(-6) mol/L) into a lung segment. This led to localized TNF synthesis measured in bronchoalveolar lavage fluid with peak concentrations of 580 pg/ml after 1 1/2 hours and 120 pg/ml after 3 hours. These values were higher than after lavage with 0.1 ml saline solution: 0.7 and 4.3 pg/ml, respectively (both p < 0.05). There was a delay before PMN accumulated in bronchoalveolar lavage fluid (x 10(4)). After 30 minutes, the numbers were 2.2 PMN/ml, whereas at 4 hours there was a rise to 40 PMN/ml and at 5 hours 60 PMN/ml, higher than after saline lavage (all p < 0.05). Pretreatment of rats by lavage into airways with actinomycin D, 12 ng in 0.1 ml, minimized LTB4-induced TNF synthesis after 1 1/2 and 3 hours (38 and 51 pg/ml), as well as the delayed Diapedesis after 4 hours (12 PMN/ml) (all p < 0.05). Similarly, pretreatment of other rats by lavage with TNF-alpha antiserum (rabbit antimurine), but not normal serum, limited LTB4-induced Diapedesis (13 PMN/ml) (p < 0.05). Interestingly, administration of the protein synthesis inhibitor actinomycin D by lavage 10 minutes after LTB4 did not prevent TNF generation after 1 1/2 or 3 hours (490 and 440 pg/ml). However, this agent did limit PMN Diapedesis after 4 hours (14 PMN/ml) (p < 0.05), an event possibly caused by limiting later synthesis of endothelial adhesion proteins, a thesis consistent with the findings that pretreatment of rats by lavage with actinomycin D was without any effect on N-formyl-methionyl-phenylalanine (10(-8) mol/L)-induced Diapedesis. This agent is known to induce PMN migration without need for synthesis of endothelial adhesion proteins. The data indicate that lavage with LTB4 induces local TNF-alpha generation that in turn mediates a delayed PMN Diapedesis. This event is likely regulated by endothelial synthesis of adhesion proteins.

  • oxygen free radicals are required for ischemia induced leukotriene b4 synthesis and Diapedesis
    Surgery, 1992
    Co-Authors: G Goldman, Richard Welbourn, Joseph M Klausner, C R Valeri, David Shepro, Herbert B Hechtman
    Abstract:

    : Hind limb ischemia and reperfusion have been shown to result in high plasma levels of leukotriene B4 (LTB4) and polymorphonuclear neutrophil (PMN) sequestration in the pulmonary microvasculature. This study tests whether LTB4 is derived from PMNs and its role in mediating ischemic plasma-induced Diapedesis. Plasma derived from rabbit hind limbs after 3 hours of tourniquet ischemia and 10 minutes of reperfusion (n = 6) showed an increased LTB4 level of 560 pg/ml, higher than sham plasma values of 106 pg/ml (p less than 0.05). Introduction of ischemic plasma in abraded skin chambers placed on the dorsum of normal rabbits (n = 6) led after 3 hours to PMN Diapedesis of 1175 PMN/mm3, associated with a further increase in LTB4 levels to 820 pg/ml (both p less than 0.05). In contrast, ischemic plasma derived from neutropenic animals (n = 4; nitrogen mustard, 2 mg/kg; PMNs less than 30/mm3) contained lower levels of LTB4, 160 pg/ml (p less than 0.05). When introduced in skin chambers in normal rabbits (n = 4), this plasma induced accumulations of only 163 PMN/mm3, accompanied by a smaller increase in LTB4 levels in the blister fluid after 3 hours, 397 pg/ml (both p less than 0.05). A correlation was found between LTB4 levels in ischemic plasma and PMN accumulations in blister fluid (r = 0.92; p less than 0.05). Intravenous pretreatment of rabbits (n = 4) used in the blister chamber bioassay with the LT receptor antagonist FPL-55712, 40 micrograms/kg/hr, attenuated Diapedesis induced by ischemic and ischemic-neutropenic plasma, 103 and 35 PMN/mm3, respectively (both p less than 0.05). Pretreatment with superoxide dismutase, 1500 units/kg, and catalase, 5000 units/kg, both conjugated to polyethylene glycol (n = 4), prevented ischemic plasma-induced LTB4 synthesis, as well as ischemic plasma-induced Diapedesis, 12 PMN/mm3 (p less than 0.05). Finally, pretreatment with allopurinol, 25 mg/kg, was similarly effective in preventing LTB4 synthesis and PMN migration. These data suggest that oxygen free radicals are essential for ischemia-induced PMN synthesis of LTB4 that in turn mediates their Diapedesis.

  • thromboxane a2 induces leukotriene b4 synthesis that in turn mediates neutrophil Diapedesis via cd 18 activation
    Microvascular Research, 1991
    Co-Authors: G Goldman, Richard Welbourn, David Shepro, Robert C Valeri, Herbert B Hechtman
    Abstract:

    Abstract Previous studies have indicated that thromboxane (Tx) and leukotriene (LT) B 4 act synergistically to induce neutrophil (PMN) adhesion in the microvasculature. This study explores the ability of Tx to induce LTB 4 synthesis, which then leads to activation of PMN and endothelial adhesion receptors. Tx-mimic (U46619, 1 μg/ml) was administered into abraded skin chambers placed on the backs of rabbits ( n = 6). After 3 hr LTB 4 was synthesized in the blister fluid at 385 pg/ml, a value higher than levels in saline-treated blisters, 10 pg/ml ( P 4 generation following Tx-mimic was correlated ( P r = 0.70) with neutrophil Diapedesis. These averaged 645 PMN/mm 3 , values higher than saline values of 20 PMN/mm 3 ( P n = 4) with the lipoxygenase inhibitor diethylcarbamazine at 60 mg/kg, followed by 40 mg/kg/hr, prevented Tx-mimic-induced LTB 4 synthesis (10 pg/ml) and Diapedesis (19 PMN/mm 3 ) (both P n = 4) with the anti-CD 18 monoclonal antibody R 15.7 at 1 mg/kg abolished Tx-induced Diapedesis (3 PMN/mm 3 ) ( P 4 and the activation of neutrophil CD 18 but not endothelial adhesion proteins.

  • thromboxane mediates Diapedesis after ischemia by activation of neutrophil adhesion receptors interacting with basally expressed intercellular adhesion molecule 1
    Circulation Research, 1991
    Co-Authors: G Goldman, Richard Welbourn, Joseph M Klausner, C R Valeri, D Shepro, Herbert B Hechtman
    Abstract:

    Ischemic injury is characterized by neutrophil (PMN)--endothelial cell adhesion and Diapedesis associated with thromboxane (TX) generation. Neutrophil-endothelial cell interaction is regulated in part by the leukocyte adhesion receptor CD 18 glycoprotein complex and the endothelial intercellular adhesion molecule-1 (ICAM-1). This study tests the role of TX in ischemia-induced Diapedesis and evaluates whether the Diapedesis is regulated by neutrophil or endothelial adhesion receptors. Plasma derived from rabbit hind limbs made ischemic for 3 hours (n = 6) and reperfused for 10 minutes had increased levels of TXB2 3,450 pg/ml, which was higher than sham rabbit (n = 6) values of 653 pg/ml (p less than 0.05). When introduced into abraded skin chambers placed on the dorsum of other normal rabbits (n = 6), this ischemic plasma induced 1,000 pg/ml of new TX synthesis and Diapedesis of 1,235 PMN/mm3. The total TX concentration and PMN accumulations in blister fluid were correlated (r = 0.88, p less than 0.05). In contrast, sham rabbit plasma induced no TX synthesis and Diapedesis of only 77 PMN/mm3 (p less than 0.05). Administration of 50 ng/ml of authentic TXB2 into blisters induced an accumulation of 453 PMN/mm3, which was higher than that in saline controls (18 PMN/mm3) (p less than 0.05). Pretreatment of normal rabbits used for the Diapedesis assay (n = 4) with the TX synthetase inhibitor OKY 046 (2 mg/kg/hr) limited ischemic plasma and authentic TXB2 induced Diapedesis to 142 and 76 PMN/mm3, respectively (both p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

  • intravascular chemoattractants inhibit Diapedesis by selective receptor occupancy
    American Journal of Physiology-heart and Circulatory Physiology, 1991
    Co-Authors: G Goldman, Richard Welbourn, Joseph M Klausner, C R Valeri, D Shepro, Lester Kobzik, Herbert B Hechtman
    Abstract:

    : An extravascular chemoattractant leads to migration of polymorphonuclear neutrophils (PMN) to that site, whereas intravascular administration leads to PMN oxidative activity and sequestration in microvessels but no Diapedesis. This study examines the inhibitory role of intravascular chemoattractants. Rabbits (n = 37) were pretreated with zymosan-activated plasma (ZAP), leukotriene (LT) B4, or thromboxane (Tx) mimic. These agents were given intra-arterially, topically into plastic chambers taped atop sites of dermabrasion on the back, or into a lobar bronchus (n = 35). Intra-arterial injection of each chemoattractant resulted, 10 min later, in a 29-42% increase in intracellular PMN H2O2. In saline-infused animals, topical administration of the chemoattractants into dermabrasion chambers resulted in PMN accumulation per cubic millimeter after 3 h of 600 with ZAP, 536 with LTB4, and 643 with Tx mimic; all values higher than 46 with saline and 63 with normal plasma (all P less than 0.05). In other saline-infused animals, lobar lung aspiration of chemoattractants led to Diapedesis as measured in bronchoalveolar lavage (BAL) fluid (PMN x 10(4)/ml) after 3 h: 19.0 with ZAP, 11.2 with LTB4 and 14.5 with Tx mimic, all greater than aspiration with saline or normal plasma 4.0 and 4.9, respectively (all P less than 0.05). Intra-arterial chemotactic administration inhibited subsequent PMN Diapedesis in response to that same chemoattractant, both in dermabrasion chambers and in BAL fluid. When different intra- and extra-vascular chemoattractants were used Diapedesis was promoted. Thus Tx infused intra-arterially and ZAP applied to a blister or lobar bronchus led to rapid cell migration and increased cell numbers.(ABSTRACT TRUNCATED AT 250 WORDS)

G Goldman - One of the best experts on this subject based on the ideXlab platform.

  • lavage with leukotriene b4 induces lung generation of tumor necrosis factor alpha that in turn mediates neutrophil Diapedesis
    Surgery, 1993
    Co-Authors: G Goldman, Richard Welbourn, C R Valeri, David Shepro, Lester Kobzik, Herbert B Hechtman
    Abstract:

    : In experimental models of acute respiratory failure, leukotriene (LT) B4 is generated in the lungs, followed by a 2- to 3-hour delay before there is substantial neutrophil (PMN) accumulation and increased permeability. This study tests whether lavage with LTB4 induces tumor necrosis factor (TNF) synthesis by the lungs that in turn mediates PMN Diapedesis. Anesthetized rats underwent lavage with 0.1 ml LTB4 (10(-6) mol/L) into a lung segment. This led to localized TNF synthesis measured in bronchoalveolar lavage fluid with peak concentrations of 580 pg/ml after 1 1/2 hours and 120 pg/ml after 3 hours. These values were higher than after lavage with 0.1 ml saline solution: 0.7 and 4.3 pg/ml, respectively (both p < 0.05). There was a delay before PMN accumulated in bronchoalveolar lavage fluid (x 10(4)). After 30 minutes, the numbers were 2.2 PMN/ml, whereas at 4 hours there was a rise to 40 PMN/ml and at 5 hours 60 PMN/ml, higher than after saline lavage (all p < 0.05). Pretreatment of rats by lavage into airways with actinomycin D, 12 ng in 0.1 ml, minimized LTB4-induced TNF synthesis after 1 1/2 and 3 hours (38 and 51 pg/ml), as well as the delayed Diapedesis after 4 hours (12 PMN/ml) (all p < 0.05). Similarly, pretreatment of other rats by lavage with TNF-alpha antiserum (rabbit antimurine), but not normal serum, limited LTB4-induced Diapedesis (13 PMN/ml) (p < 0.05). Interestingly, administration of the protein synthesis inhibitor actinomycin D by lavage 10 minutes after LTB4 did not prevent TNF generation after 1 1/2 or 3 hours (490 and 440 pg/ml). However, this agent did limit PMN Diapedesis after 4 hours (14 PMN/ml) (p < 0.05), an event possibly caused by limiting later synthesis of endothelial adhesion proteins, a thesis consistent with the findings that pretreatment of rats by lavage with actinomycin D was without any effect on N-formyl-methionyl-phenylalanine (10(-8) mol/L)-induced Diapedesis. This agent is known to induce PMN migration without need for synthesis of endothelial adhesion proteins. The data indicate that lavage with LTB4 induces local TNF-alpha generation that in turn mediates a delayed PMN Diapedesis. This event is likely regulated by endothelial synthesis of adhesion proteins.

  • oxygen free radicals are required for ischemia induced leukotriene b4 synthesis and Diapedesis
    Surgery, 1992
    Co-Authors: G Goldman, Richard Welbourn, Joseph M Klausner, C R Valeri, David Shepro, Herbert B Hechtman
    Abstract:

    : Hind limb ischemia and reperfusion have been shown to result in high plasma levels of leukotriene B4 (LTB4) and polymorphonuclear neutrophil (PMN) sequestration in the pulmonary microvasculature. This study tests whether LTB4 is derived from PMNs and its role in mediating ischemic plasma-induced Diapedesis. Plasma derived from rabbit hind limbs after 3 hours of tourniquet ischemia and 10 minutes of reperfusion (n = 6) showed an increased LTB4 level of 560 pg/ml, higher than sham plasma values of 106 pg/ml (p less than 0.05). Introduction of ischemic plasma in abraded skin chambers placed on the dorsum of normal rabbits (n = 6) led after 3 hours to PMN Diapedesis of 1175 PMN/mm3, associated with a further increase in LTB4 levels to 820 pg/ml (both p less than 0.05). In contrast, ischemic plasma derived from neutropenic animals (n = 4; nitrogen mustard, 2 mg/kg; PMNs less than 30/mm3) contained lower levels of LTB4, 160 pg/ml (p less than 0.05). When introduced in skin chambers in normal rabbits (n = 4), this plasma induced accumulations of only 163 PMN/mm3, accompanied by a smaller increase in LTB4 levels in the blister fluid after 3 hours, 397 pg/ml (both p less than 0.05). A correlation was found between LTB4 levels in ischemic plasma and PMN accumulations in blister fluid (r = 0.92; p less than 0.05). Intravenous pretreatment of rabbits (n = 4) used in the blister chamber bioassay with the LT receptor antagonist FPL-55712, 40 micrograms/kg/hr, attenuated Diapedesis induced by ischemic and ischemic-neutropenic plasma, 103 and 35 PMN/mm3, respectively (both p less than 0.05). Pretreatment with superoxide dismutase, 1500 units/kg, and catalase, 5000 units/kg, both conjugated to polyethylene glycol (n = 4), prevented ischemic plasma-induced LTB4 synthesis, as well as ischemic plasma-induced Diapedesis, 12 PMN/mm3 (p less than 0.05). Finally, pretreatment with allopurinol, 25 mg/kg, was similarly effective in preventing LTB4 synthesis and PMN migration. These data suggest that oxygen free radicals are essential for ischemia-induced PMN synthesis of LTB4 that in turn mediates their Diapedesis.

  • thromboxane a2 induces leukotriene b4 synthesis that in turn mediates neutrophil Diapedesis via cd 18 activation
    Microvascular Research, 1991
    Co-Authors: G Goldman, Richard Welbourn, David Shepro, Robert C Valeri, Herbert B Hechtman
    Abstract:

    Abstract Previous studies have indicated that thromboxane (Tx) and leukotriene (LT) B 4 act synergistically to induce neutrophil (PMN) adhesion in the microvasculature. This study explores the ability of Tx to induce LTB 4 synthesis, which then leads to activation of PMN and endothelial adhesion receptors. Tx-mimic (U46619, 1 μg/ml) was administered into abraded skin chambers placed on the backs of rabbits ( n = 6). After 3 hr LTB 4 was synthesized in the blister fluid at 385 pg/ml, a value higher than levels in saline-treated blisters, 10 pg/ml ( P 4 generation following Tx-mimic was correlated ( P r = 0.70) with neutrophil Diapedesis. These averaged 645 PMN/mm 3 , values higher than saline values of 20 PMN/mm 3 ( P n = 4) with the lipoxygenase inhibitor diethylcarbamazine at 60 mg/kg, followed by 40 mg/kg/hr, prevented Tx-mimic-induced LTB 4 synthesis (10 pg/ml) and Diapedesis (19 PMN/mm 3 ) (both P n = 4) with the anti-CD 18 monoclonal antibody R 15.7 at 1 mg/kg abolished Tx-induced Diapedesis (3 PMN/mm 3 ) ( P 4 and the activation of neutrophil CD 18 but not endothelial adhesion proteins.

  • lavage of leukotriene b4 induces lung generation of tumor necrosis factor a and neutrophil Diapedesis
    1991
    Co-Authors: G Goldman, Richard Welbourn, C R Valeri, Lester Kobzik, David Shepro
    Abstract:

    Abstract : In experimental models of acute respiratory failure leukotriene (LT) B sub 4 is generated in the lungs, followed by a 2 to 3 hour delay before there is substantial neutrophil (PMN) accumulation and increased permeability. This study tests whether lavage of LTB sub 4 induces tumor necrosis factor (TNF) synthesis by the lungs that in turn mediates PMN Diapedesis. Anesthetized rats underwent lavage of 0.1 ml LTB sub 4 (10(exp -6) M) into a lung segment. This led to localized TNF synthesis measured in bronchoalveolar lavage fluid (BAL) with peak concentrations of 580 pg/ml after 1.5 hours and 120 pg/ml after 3 hours. These values were higher than following lavage of 0.1 ml saline, 0.7 pg/ml and 4.3 pg/ml respectively (both p<0.05). There was a delay before PMN accumulated in BAL fluid (x 10(exp 4)). After 30 min the numbers were 2.2 PMN/ml while at 4 hours there was a rise to 40 PMN/ml and at 5 hours 60 PMN/ml, higher than following saline lavage (all p<0.05). Pretreatment of rats by lavage into airways of actinomycin D, 12 ng in 0.1 ml, minimized LTB sub 4 induced TNF synthesis after 1.5 and 3 hours (38 pg/ml and 51 pg/ml) as well as the delayed Diapedesis after 4 hours (12 PMN/ml) (all p<0.05). Similarly, pretreatment of other rats by lavage of TNF-alpha antiserum (rabbit anti-murine), but not normal serum, limited LTB sub 4 induced Diapedesis (13 PMN/ml) (p<0.05). Interestingly, administration of the protein synthesis inhibitor actinomycin D by lavage 10 min after LTB sub 4 did not prevent TNF generation after 1.5 or 3 hours (490 pg/ml and 440 pg/ml). However, this agent did limit PMN Diapedesis after 4 hours (14 PMN/ml) (p<0.05). In contrast, pretreatment of rats by lavage with actinomycin D was without any effect on N-formyl-methionyl-phenylalanine (10(exp -8) M) induced Diapedesis.

  • Lavage of Leukotriene B4 Induces Lung Generation of Tumor Necrosis Factor-A and Neutrophil Diapedesis.
    1991
    Co-Authors: G Goldman, Richard Welbourn, C R Valeri, Lester Kobzik, David Shepro
    Abstract:

    Abstract : In experimental models of acute respiratory failure leukotriene (LT) B sub 4 is generated in the lungs, followed by a 2 to 3 hour delay before there is substantial neutrophil (PMN) accumulation and increased permeability. This study tests whether lavage of LTB sub 4 induces tumor necrosis factor (TNF) synthesis by the lungs that in turn mediates PMN Diapedesis. Anesthetized rats underwent lavage of 0.1 ml LTB sub 4 (10(exp -6) M) into a lung segment. This led to localized TNF synthesis measured in bronchoalveolar lavage fluid (BAL) with peak concentrations of 580 pg/ml after 1.5 hours and 120 pg/ml after 3 hours. These values were higher than following lavage of 0.1 ml saline, 0.7 pg/ml and 4.3 pg/ml respectively (both p