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At least 631 records · Page 35Linked to original sources
PubMed2003

Differential regulation of aminopeptidase N (CD13) by transendothelial migration and cytokines on human eosinophils.

Aminopeptidase N (CD13) is a cell surface metalloprotease involved in growth regulation, tumor invasion, and down-regulation of regulatory peptides. CD13 expression on eosinophils in bronchoalveolar lavage (BAL) of asthmatics 10 minutes and 18 hours after segmental allergen provocation was significantly increased (+225% to +294%) compared to blood eosinophils. In vitro CD13 expression could be induced on blood eosinophils by transendothelial migration of the cells across interlenkin (IL) 1beta-activated human umbilical cord vein endothelial cells (HUVECs) as well as by the exposure to the cytokines IL-3, IL-5, and granulocyte-macrophage colony-stimulating factor (GM-CSF). The cytokines GM-CSF and IL-5 were significantly less effective in inducing CD13 compared to IL-3. The IL-3-induced expression of CD13 was decreased in the presence of the protein-synthesis inhibitor cycloheximide (-8.8%). Moreover, blocking of CD13 by the protease inhibitors actinonin and bestatin significantly enhanced migration (+40.0% to +80.0%) of eosinophils across HUVEC monolayers. In summary, the data suggest that CD13 is regulated both by the process of transmigration and by the cytokine IL-3. Further, CD13 itself seems to be involved in the process of eosinophil transmigration. aminopeptidase Nendothelial cellseosinophilsinterleukin-3interleukin-5transendothelial migration

Adult↗
PubMedDate not supplied

Cardiac surgery with extracorporeal circulation: neutrophil transendothelial migration is mediated by beta1 integrin (CD29) in the presence of TNF-alpha.

Cardiac surgery with extracorporeal circulation is associated with neutrophil activation, inflammation, and edema. Endothelial hyperpermeability elicited by the interaction of activated neutrophils and/or cytokines with endothelial cells may be critical in this regard. However, the immune and cellular mechanisms involved are not fully understood. Cocultures with human endothelial cells and neutrophils from cardiac surgery patients were used to evaluate the role of beta1 integrin activity and the proinflammatory cytokine tumor necrosis factor (TNF)-alpha in neutrophil transendothelial migration and in impairment of the integrity of endothelial cell-to-cell contacts. Blocking of CD29 (heavy chain of beta1 integrins) totally prevented neutrophil adhesion and transendothelial migration. Pretreatment of neutrophils with either a CD29-stimulating monoclonal antibody or the addition of TNF-alpha (0.1-10 U/ml) to the coculture failed to induce transendothelial migration. However, coculture of endothelial cells with CD29-stimulated neutrophils in the presence of 0.1-10 U/ml TNF-alpha strongly induced neutrophil transmigration. CD29/TNF-alpha-mediated transmigration was associated with intracellular redistribution of endothelial beta-catenin. We further showed that CD29/TNF-alpha-mediated effects involved PI3K and tyrosine kinase-dependent signaling via MAPK but were independent of nuclear transcription factor (NF)-kappaB activity. Inhibition of CD29/TNF-alpha might be a therapeutic option to limit endothelial dysfunction following cardiac surgery with extracorporeal circulation.

Cell Movement↗
PubMedDate not supplied

Inhibitory effects of TSG-6 Link module on leukocyte-endothelial cell interactions in vitro and in vivo.

OBJECTIVE: The authors investigated whether the anti-inflammatory protein tumor necrosis factor (TNF)-stimulated gene-6 (TSG-6) and its Link module (Link_TSG6) could affect the complex multistep process of leukocyte/endothelial cell (EC) interaction. METHODS: Mouse mesenteries were inflamed with interleukin (IL)-1beta and the extent of leukocyte rolling, adhesion, and emigration was determined after 2 h. Link_TSG6 and a single-point mutant (termed K13E) were given intraperitoneally together with the cytokine. Human neutrophil chemotaxis and transmigration were determined in vitro in response to IL-8 and/or TNF-alpha. TSG-6, Link_TSG6, and K13E were added to the leukocytes or the EC monolayers. RESULTS: Co-injection of Link_TSG6 with IL-1beta selectively inhibited cell flux, adhesion, and emigration as analyzed in mesenteric postcapillary venules. The fewer cells that rolled in the animals treated with Link_TSG6 displayed a velocity similar to that measured in vehicle-treated mice. In vitro, Link_TSG6 did not affect neutrophil chemotaxis or EC activation but did inhibit neutrophil transmigration across EC monolayers. The latter effect was shared by full-length TSG-6 and observed equally in response to IL-8 or TNF-alpha. CONCLUSIONS: These data restrict the site of action for at least some of the anti-inflammatory effects ascribed to TSG-6/Link_TSG6 to the microenvironment of the extravasating leukocyte.

Animals↗
PubMed1992

Neutrophil migration across monolayers of cytokine-prestimulated endothelial cells: a role for platelet-activating factor and IL-8.

In a previous study we observed that neutrophils respond with a rapid rise in [Ca2+]i during adherence to cytokine-activated endothelial cells (EC), caused by EC membrane-associated platelet-activating factor (PAF). In the present study, we investigated whether this form of PAF was important in neutrophil adherence and migration across monolayers of rIL-1 beta- or rTNF alpha-prestimulated EC. PAF receptor antagonists prevented neutrophil migration across cytokine-pretreated EC by approximately 60% (P less than 0.005) without interfering with the process of adherence. The antagonists WEB 2086 and L-652,731 had no effect on neutrophil migration across resting EC induced by formylmethionyl-leucyl-phenylalanine (FMLP). A murine anti-IL-8 antiserum was found to also partially inhibit the neutrophil transmigration across cytokine-activated EC. When the anti-IL-8 antiserum was used in combination with a PAF receptor antagonist, neutrophil migration across cytokine-pretreated monolayers of EC was completely prevented. During transmigration, LAM-1 and CD44 on the neutrophils were down-modulated; both WEB 2086 and anti-IL-8 antiserum partially prevented this down-modulation caused by cytokine-prestimulated EC. Our results indicate that human neutrophils are activated and guided by EC-associated PAF and EC-derived IL-8 during the in vitro diapedesis in between cytokine-stimulated EC.

Antigens, Surface↗
PubMed1993

Salmonella typhimurium attachment to human intestinal epithelial monolayers: transcellular signalling to subepithelial neutrophils.

In human intestinal disease induced by Salmonella typhimurium, transepithelial migration of neutrophils (PMN) rapidly follows attachment of the bacteria to the epithelial apical membrane. In this report, we model those interactions in vitro, using polarized monolayers of the human intestinal epithelial cell, T84, isolated human PMN, and S. typhimurium. We show that Salmonella attachment to T84 cell apical membranes did not alter monolayer integrity as assessed by transepithelial resistance and measurements of ion transport. However, when human neutrophils were subsequently placed on the basolateral surface of monolayers apically colonized by Salmonella, physiologically directed transepithelial PMN migration ensued. In contrast, attachment of a non-pathogenic Escherichia coli strain to the apical membrane of epithelial cells at comparable densities failed to stimulate a directed PMN transepithelial migration. Use of the n-formyl-peptide receptor antagonist N-t-BOC-1-methionyl-1-leucyl-1- phenylalanine (tBOC-MLP) indicated that the Salmonella-induced PMN transepithelial migration response was not attributable to the classical pathway by which bacteria induce directed migration of PMN. Moreover, the PMN transmigration response required Salmonella adhesion to the epithelial apical membrane and subsequent reciprocal protein synthesis in both bacteria and epithelial cells. Among the events stimulated by this interaction was the epithelial synthesis and polarized release of the potent PMN chemotactic peptide interleukin-8 (IL-8). However, IL-8 neutralization, transfer, and induction experiments indicated that this cytokine was not responsible for the elicited PMN transmigration. These data indicate that a novel transcellular pathway exists in which subepithelial PMN respond to lumenal pathogens across a functionally intact epithelium. Based on the known unique characteristics of the intestinal mucosa, we speculate that IL-8 may act in concert with an as yet unidentified transcellular chemotactic factor(s) (TCF) which directs PMN migration across the intestinal epithelium.

Bacterial Adhesion↗
PubMed1996

Polymorphonuclear leukocyte adhesion triggers the disorganization of endothelial cell-to-cell adherens junctions.

Polymorphonuclear leukocytes (PMN) infiltration into tissues is frequently accompanied by increase in vascular permeability. This suggests that PMN adhesion and transmigration could trigger modifications in the architecture of endothelial cell-to-cell junctions. In the present paper, using indirect immunofluorescence, we found that PMN adhesion to tumor necrosis factor-activated endothelial cells (EC) induced the disappearance from endothelial cell-to-cell contacts of adherens junction (AJ) components: vascular endothelial (VE)-cadherin, alpha-catenin, beta-catenin, and plakoglobin. Immunoprecipitation and Western blot analysis of the VE-cadherin/catenin complex showed that the amount of beta-catenin and plakoglobin was markedly reduced from the complex and from total cell extracts. In contrast, VE-cadherin and alpha-catenin were only partially affected. Disorganization of endothelial AJ by PMN was not accompanied by EC retraction or injury and was specific for VE-cadherin/catenin complex, since platelet/endothelial cell adhesion molecule 1 (PECAM-1) distribution at cellular contacts was unchanged. PMN adhesion to EC seems to be a prerequisite for VE-cadherin/catenin complex disorganization. This phenomenon could be fully inhibited by blocking PMN adhesion with an anti-integrin beta 2 mAb, while it could be reproduced by any condition that induced increase of PMN adhesion, such as addition of PMA or an anti-beta 2-activating mAb. The effect on endothelial AJ was specific for PMN since adherent activated lymphocytes did not induce similar changes. High concentrations of protease inhibitors and oxygen metabolite scavengers were unable to prevent AJ disorganization mediated by PMN. PMN adhesion to EC was accompanied by increase in EC permeability in vitro. This effect was dependent on PMN adhesion, was not mediated by proteases and oxygen-reactive metabolites, and could be reproduced by EC treatment with EGTA. Finally, immunohistochemical analysis showed that VE-cadherin distribution was affected by PMN adhesion to the vessel wall in vivo too. This work suggests that PMN adhesion could trigger intracellular signals in EC that possibly regulate VE-cadherin /catenin complex disorganization. This effect could increase EC permeability and facilitate PMN transmigration during the acute inflammatory reaction.

Blotting, Western↗
PubMed1997

Tyrosine residue in exon 14 of the cytoplasmic domain of platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) regulates ligand binding specificity.

Platelet/endothelial cell adhesion molecule (PECAM-1) is a cell adhesion molecule of the immunoglobulin superfamily that plays a role in a number of vascular processes including leukocyte transmigration through endothelium. The presence of a specific 19- amino acid exon within the cytoplasmic domain of PECAM-1 regulates the binding specificity of the molecule; specifically, isoforms containing exon 14 mediate heterophilic cell-cell aggregation while those variants missing exon 14 mediate homophilic cell-cell aggregation. To more precisely identify the region of exon 14 responsible for ligand specificity, a series of deletion mutants were created in which smaller regions of exon 14 were removed. After transfection into L cells, they were tested for their ability to mediate aggregation. For heterophilic aggregation to occur, a conserved 5-amino acid region (VYSEI in the murine sequence or VYSEV in the human sequence) in the mid-portion of the exon was required. A final construct, in which this tyrosine was mutated into a phenylalanine, aggregated in a homophilic manner when transfected into L cells. Inhibition of phosphatase activity by exposure of cells expressing wild type or mutant forms of PECAM-1 to sodium orthovanadate resulted in high levels of cytoplasmic tyrosine phosphorylation and led to a switch from heterophilic to homophilic aggregation. Our data thus indicate either loss of this tyrosine from exon 14 or its phosphorylation results in a change in ligand specificity from heterophilic to homophilic binding. Vascular cells could thus determine whether PECAM-1 functions as a heterophilic or homophilic adhesion molecule by processes such as alternative splicing or by regulation of the balance between tyrosine phosphorylation or dephosphorylation. Defining the conditions under which these changes occur will be important in understanding the biology of PECAM-1 in transmigration, angiogenesis, development, and other processes in which this molecule plays a role.

Alternative Splicing↗
PubMed2004

A transmigratory cup in leukocyte diapedesis both through individual vascular endothelial cells and between them.

The basic route and mechanisms for leukocyte migration across the endothelium remain poorly defined. We provide definitive evidence for transcellular (i.e., through individual endothelial cells) diapedesis in vitro and demonstrate that virtually all, both para- and transcellular, diapedesis occurs in the context of a novel "cuplike" transmigratory structure. This endothelial structure was comprised of highly intercellular adhesion molecule-1- and vascular cell adhesion molecule-1-enriched vertical microvilli-like projections that surrounded transmigrating leukocytes and drove redistribution of their integrins into linear tracks oriented parallel to the direction of diapedesis. Disruption of projections was highly correlated with inhibition of transmigration. These findings suggest a novel mechanism, the "transmigratory cup", by which the endothelium provides directional guidance to leukocytes for extravasation.

Antigens, CD↗
PubMed1999

Leukocyte recruitment in the cerebrospinal fluid of mice with experimental meningitis is inhibited by an antibody to junctional adhesion molecule (JAM).

The mechanisms that govern leukocyte transmigration through the endothelium are not yet fully defined. Junctional adhesion molecule (JAM) is a newly cloned member of the immunoglobulin superfamily which is selectively concentrated at tight junctions of endothelial and epithelial cells. A blocking monoclonal antibody (BV11 mAb) directed to JAM was able to inhibit monocyte transmigration through endothelial cells in in vitro and in vivo chemotaxis assays. In this study, we report that BV11 administration was able to attenuate cytokine-induced meningitis in mice. The intravenous injection of BV11 mAb significantly inhibited leukocyte accumulation in the cerebrospinal fluid and infiltration in the brain parenchyma. Blood-brain barrier permeability was also reduced by the mAb. We conclude that JAM may be a new target in limiting the inflammatory response that accompanies meningitis.

Animals↗
PubMed2002

Multidrug efflux systems play an important role in the invasiveness of Pseudomonas aeruginosa.

Pseudomonas aeruginosa is an important opportunistic human pathogen. Certain strains can transmigrate across epithelial cells, and their invasive phenotype is correlated with capacity to cause invasive human disease and fatal septicemia in mice. Four multidrug efflux systems have been described in P. aeruginosa, however, their contribution to virulence is unclear. To clarify the role of efflux systems in invasiveness, P. aeruginosa PAO1 wild-type (WT) and its efflux mutants were evaluated in a Madin-Darby canine kidney (MDCK) epithelial cell monolayer system and in a murine model of endogenous septicemia. All efflux mutants except a deltamexCD-oprJ deletion demonstrated significantly reduced invasiveness compared with WT. In particular, a deltamexAB-oprM deletion strain was compromised in its capacity to invade or transmigrate across MDCK cells, and could not kill mice, in contrast to WT which was highly invasive (P < 0.0006) and caused fatal infection (P < 0.0001). The other mutants, including deltamexB and deltamexXY mutants, were intermediate between WT and the deltamexAB-oprM mutant in invasiveness and murine virulence. Invasiveness was restored to the deltamexAB-oprM mutant by complementation with mexAB-oprM or by addition of culture supernatant from MDCK cells infected with WT. We conclude that the P. aeruginosa MexAB-OprM efflux system exports virulence determinants that contribute to bacterial virulence.

Animals↗
PubMed2002

Transepithelial migration of Toxoplasma gondii is linked to parasite motility and virulence.

After oral ingestion, Toxoplasma gondii crosses the intestinal epithelium, disseminates into the deep tissues, and traverses biological barriers such as the placenta and the blood-brain barrier to reach sites where it causes severe pathology. To examine the cellular basis of these processes, migration of T. gondii was studied in vitro using polarized host cell monolayers and extracellular matrix. Transmigration required active parasite motility and the highly virulent type I strains consistently exhibited a superior migratory capacity than the nonvirulent type II and type III strains. Type I strain parasites also demonstrated a greater capacity for transmigration across mouse intestine ex vivo, and directly penetrated into the lamina propria and vascular endothelium. A subpopulation of virulent type I parasites exhibited a long distance migration (LDM) phenotype in vitro, that was not expressed by nonvirulent type II and type III strains. Cloning of parasites expressing the LDM phenotype resulted in substantial increase of migratory capacity in vitro and in vivo. The potential to up-regulate migratory capacity in T. gondii likely plays an important role in establishing new infections and in dissemination upon reactivation of chronic infections.

Animals↗
PubMed2005

Eosinophil adhesion under flow conditions activates mechanosensitive signaling pathways in human endothelial cells.

Leukocyte transmigration can be affected by shear stress; however, the mechanisms by which shear stress modulates transmigration are unknown. We found that adhesion of eosinophils or an eosinophilic cell line to intereukin 4-stimulated endothelial cells led to a shear-dependent increase in endothelial cell intracellular calcium and increased phosphorylation of extracellular signal-regulated kinase (ERK) 2, but not c-Jun NH2-terminal kinase or p38 mitogen-activated protein kinase. Latex beads coated with antibodies were used to characterize the role of specific endothelial cell surface molecules in initiating signaling under shear conditions. We found that ligation of either vascular cell adhesion molecule-1 or E-selectin, but not major histocompatibility complex class I, induced a shear-dependent increase in ERK2 phosphorylation in cytokine-stimulated endothelial cells. Disassembly of the actin cytoskeleton with latrunculin A prevented ERK2 phosphorylation after adhesion under flow conditions, supporting a role for the cytoskeleton in mechano-sensing. Rapid phosphorylation of focal adhesion kinase and paxillin occurred under identical conditions, suggesting that focal adhesions were also involved in mechanotransduction. Finally, we found that Rho-associated protein kinase and calpain were both critical in the subsequent transendothelial migration of eosinophils under flow conditions. These data suggest that ligation of leukocyte adhesion molecules under flow conditions leads to mechanotransduction in endothelial cells, which can regulate subsequent leukocyte trafficking.

Actins↗
PubMed2006

Intraluminal crawling of neutrophils to emigration sites: a molecularly distinct process from adhesion in the recruitment cascade.

The prevailing view is that the beta2-integrins Mac-1 (alphaMbeta2, CD11b/CD18) and LFA-1 (alphaLbeta2, CD11a/CD18) serve similar biological functions, namely adhesion, in the leukocyte recruitment cascade. Using real-time and time-lapse intravital video-microscopy and confocal microscopy within inflamed microvessels, we systematically evaluated the function of Mac-1 and LFA-1 in the recruitment paradigm. The chemokine macrophage inflammatory protein-2 induced equivalent amounts of adhesion in wild-type and Mac-1-/- mice but very little adhesion in LFA-1-/- mice. Time-lapse video-microscopy within the postcapillary venules revealed that immediately upon adhesion, there is significant intraluminal crawling of all neutrophils to distant emigration sites in wild-type mice. In dramatic contrast, very few Mac-1-/- neutrophils crawled with a 10-fold decrease in displacement and a 95% reduction in velocity. Therefore, Mac-1-/- neutrophils initiated transmigration closer to the initial site of adhesion, which in turn led to delayed transmigration due to movement through nonoptimal emigration sites. Interestingly, the few LFA-1-/- cells that did adhere crawled similarly to wild-type neutrophils. Intercellular adhesion molecule-1 but not intercellular adhesion molecule-2 mediated the Mac-1-dependent crawling. These in vivo results clearly delineate two fundamentally different molecular mechanisms for LFA-1 and Mac-1 in vivo, i.e., LFA-1-dependent adhesion followed by Mac-1-dependent crawling, and both steps ultimately contribute to efficient emigration out of the vasculature.

Animals↗
PubMed2001

Cadaverine prevents the escape of Shigella flexneri from the phagolysosome: a connection between bacterial dissemination and neutrophil transepithelial signaling.

Shigella flexneri causes bacillary dysentery in humans by invading epithelial cells of the colon, which is characterized by an acute polymorphonuclear leukocyte (PMNL)-rich inflammation. Our recent studies demonstrated that cadaverine, a polyamine, specifically acts to abrogate transepithelial signaling to PMNL induced by S. flexneri. Here, insight is provided into the cellular mechanisms by which cadaverine attenuates the ability of Shigella species to induce PMNL signaling. It was found that cadaverine retards the lysis of the Shigella species-containing vacuole, suggesting that a blockade is established, in which the pathogen is prevented from adequately interacting with the cytoskeleton. Furthermore, an IcsA mutant of S. flexneri that cannot interact with the cytoskeleton and spreads intercellularly fails to induce transmigration of PMNL. Results indicate that cadaverine-induced compartmentalization of Shigella species to the phagolysosome might be a protective response of the host that directly contributes to the diminished ability of PMNL to transmigrate across model intestinal epithelia.

Bacterial Proteins↗
PubMed1998

Cytomegalovirus-infected endothelial cells recruit neutrophils by the secretion of C-X-C chemokines and transmit virus by direct neutrophil-endothelial cell contact and during neutrophil transendothelial migration.

Infection of endothelial cells with an endothelial cell-tropic clinical isolate of cytomegalovirus (CMV), C1FE, induced enhanced production of the neutrophil chemoattractant C-X-C chemokines interleukin-8 and GROalpha. Infected endothelial cell supernatants induced neutrophil chemotaxis in a transendothelial migration assay. Neutrophils acquired the CMV structural protein pp65 following either coculture with infected endothelial cells or transmigration through infected endothelium. The lack of CMV p72 expression in the neutrophils indicated that viral replication had not occurred in these cells. Of importance, neutrophils acquired infectious CMV during transmigration across infected endothelium and were subsequently able to transmit infectious virus to fibroblasts. Thus, CMV-infected endothelial cells can recruit neutrophils by the secretion of C-X-C chemokines and can transmit the virus to them by direct cell-to-cell contact and during neutrophil transendothelial migration, suggesting that the neutrophil-endothelial cell interaction plays an important role in virus dissemination in vivo.

Cell Communication↗
PubMed2001

Attenuation of pancreatitis-induced pulmonary injury by aerosolized hypertonic saline.

BACKGROUND: The immunomodulatory effects of hypertonic saline (HTS) provide potential strategies to attenuate inappropriate inflammatory reactions. This study tested the hypothesis that administration of intratracheal aerosolized HTS modulates the development of lung injury in pancreatitis. METHODS: Pancreatitis was induced in 24 male Sprague-Dawley rats by intraperitoneal injection of 20% L-arginine (500 mg/100 g body weight). At 24 and 48 h, intratracheal aerosolized HTS (7.5% NaCl, 0.5 mL) was administered to 8 rats, while a further 8 received 0.5 mL of aerosolized normal saline (NS). At 72 hours, pulmonary neutrophil infiltration (myeloperoxidase activity) and endothelial permeability (bronchoalveolar lavage and wet:dry weight ratios) were assessed. In addition, histological assessment of representative lung tissue was performed by a blinded assessor. In a separate experiment, polymorphonucleocytes (PMN) were isolated from human donors, and exposed to increments of HTS. Neutrophil transmigration across an endothelial cell layer, VEGF release, and apoptosis at 1, 6, 12, 18, and 24 h were assessed. RESULTS: Histopathological lung injury scores were significantly reduced in the HTS group (4.78 +/- 1.43 vs. 8.64 +/- 0.86); p < 0.001). Pulmonary neutrophil sequestration (1.40 +/- 0.2) and increased endothelial permeability (6.77 +/- 1.14) were evident in the animals resuscitated with normal saline when compared with HTS (0.70 +/- 0.1 and 3.57 +/- 1.32), respectively; p < 0.04). HTS significantly reduced PMN transmigration (by 97.1, p = 0.002, and induced PMN apoptosis (p < 0.03). HTS did not impact significantly upon neutrophil VEGF release (p > 0.05). CONCLUSIONS: Intratracheal aerosolized HTS attenuates the neutrophil-mediated pulmonary insult subsequent to pancreatitis. This may represent a novel therapeutic strategy.

Acute Disease↗
PubMed2001

Response of human CD34+ cells to CXC, CC, and CX3C chemokines: implications for cell migration and activation.

Ultrastructural studies of marrow and examination of the in vivo processes of stem cell homing and mobilization show that multipotential hematopoietic progenitors are able to traverse endothelial cells. The regulation of this process by various classes of chemokines was studied in this report, using an in vitro model of transendothelial migration. Human umbilical vein endothelial cells (HUVECs) or bone marrow-derived endothelial cells (BMECs) were grown to confluence on 3-microm microporous membrane inserts and placed in 24-well culture plates. CD34(+) cells isolated from normal volunteer donor marrow by immunoadsorption or magnetic bead selection techniques were added to the inserts and various individual chemokines were added to the lower chamber of the culture plates in serum-free conditions. After 24 h, the percentage of transmigrated cells was determined. A mean of 8.5% of unfractionated marrow CD34(+) populations migrated, and all chemokines tested, with the exception of macrophage inflammatory protein-1alpha (MIP-1alpha), had some positive effect on this migration. The greatest effects were seen with stroma-derived factor-1alpha (SDF-1alpha) and stroma-derived factor-1beta (SDF-1beta), with lesser effects noted for other chemokines and cytokines. When the CD34(+) population was subselected for expression of CD38, a greater fraction of the CD38(-) cells migrated as compared to the CD38(+) fraction. CD34(+) cells isolated from mobilized peripheral blood and cord blood also migrated in response to chemokines. Chemokines of the CC, CXC, and CX(3)C classes as well as other hematopoietic cytokines may modulate the process of stem cell transmigration of endothelial cells. Further understanding of this process may help elucidate the mechanism of stem cell mobilization and homing.

Antibodies↗
PubMed2003

Differential caveolin-1 polarization in endothelial cells during migration in two and three dimensions.

Endothelial cell (EC) migration is a critical event during multiple physiological and pathological processes. ECs move in the plane of the endothelium to heal superficially injured blood vessels but migrate in three dimensions during angiogenesis. We herein investigate differences in these modes of movement focusing on caveolae and their defining protein caveolin-1. Using a novel approach for morphological analysis of transmigrating cells, we show that ECs exhibit a polarized distribution of caveolin-1 when traversing a filter pore. Strikingly, in these cells caveolin-1 seems to be released from caveolar structures in the cell rear and to relocalize at the cell front in a cytoplasmic form. In contrast, during planar movement caveolin-1 is concentrated at the rear of ECs, colocalizing with caveolae. The phosphorylatable Tyr14 residue of caveolin-1 is required for polarization of the protein during transmigration but does not alter polarization during planar movement. Palmitoylation of caveolin-1 is not essential for redistribution of the protein during either mode of movement. Thus, ECs migrating in three dimensions uniquely exhibit dissociation of caveolin-1 from caveolae and phosphorylation-dependent relocalization to the cell front.

Animals↗