scholarly journals CD4-CCR5 interaction in intracellular compartments contributes to receptor expression at the cell surface

Blood ◽  
2009 ◽  
Vol 113 (9) ◽  
pp. 1938-1947 ◽  
Author(s):  
Lamia Achour ◽  
Mark G. H. Scott ◽  
Hamasseh Shirvani ◽  
Alain Thuret ◽  
Georges Bismuth ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Receptor Expression ◽  
Cell Surface Expression ◽  
Dependent Manner ◽  
Small Interfering Rnas ◽  
Concentration Dependent Manner ◽  
Monocytic Cell ◽  
Monocytic Cell Line ◽  
Intracellular Compartments

The association of CD4, a glycoprotein involved in T-cell development and antigen recognition, and CC chemokine receptor 5 (CCR5), a chemotactic G protein–coupled receptor, which regulates trafficking and effector functions of immune cells, forms the main receptor for HIV. We observed that the majority of CCR5 is maintained within the intracellular compartments of primary T lymphocytes and in a monocytic cell line, contrasting with its relatively low density at the cell surface. The CCR5-CD4 association, which occurs in the endoplasmic reticulum, enhanced CCR5 export to the plasma membrane in a concentration-dependent manner, whereas inhibition of endogenous CD4 with small interfering RNAs decreased cell-surface expression of endogenous CCR5. This effect was specific for CCR5, as CD4 did not affect cellular distribution of CXCR4, the other HIV coreceptor. These results reveal a previously unappreciated role of CD4, which contributes to regulating CCR5 export to the plasma membrane.

scholarly journals A Defect in Influenza A Virus Particle Assembly Specific to Primary Human Macrophages

mBio ◽  
2018 ◽  
Vol 9 (5) ◽  
Author(s):  
Sukhmani Bedi ◽  
Takeshi Noda ◽  
Yoshihiro Kawaoka ◽  
Akira Ono
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Influenza A ◽  
Cytochalasin D ◽  
Virus Release ◽  
Cell Type ◽  
Monocytic Cell ◽  
Monocytic Cell Line ◽  
Particle Assembly ◽  
Human Macrophages

ABSTRACTInfluenza A virus (IAV) propagates efficiently in epithelial cells, its primary target in the respiratory tract. In contrast, productive infection of most IAV strains is either blocked or highly inefficient in macrophages. The exact nature of the defect in IAV replication in human macrophages remains unknown. In this study, we showed that even compared to a monocytic cell line differentiated to macrophage-like cells, primary human monocyte-derived macrophages (MDM) are inefficient in IAV production, despite comparable levels of expression of viral glycoproteins at the plasma membrane. Correlative fluorescence scanning electron microscopy revealed that formation of budding structures at the cell surface is inefficient in MDM even though clustering of a viral glycoprotein, hemagglutinin (HA), is observed, suggesting that a step in IAV particle assembly is blocked in MDM. Using anin situproximity ligation assay, we further determined that HA associates with neuraminidase (NA) but fails to associate with another viral transmembrane protein, M2, at the MDM plasma membrane. Notably, the defects in HA-M2 association and particle assembly in MDM were reversed upon cytochalasin D treatment that inhibits actin polymerization. These results suggest that HA-M2 association on the plasma membrane is a discrete step in IAV production, which is susceptible to suppression by actin cytoskeleton in MDM. Virus release remained inefficient in MDM upon cytochalasin D treatment, suggesting the presence of an additional defect(s) in virus release in this cell type. Overall, our study revealed the presence of multiple cell-type-specific mechanisms negatively regulating IAV production at the plasma membrane in MDM.IMPORTANCEIdentification of host cell determinants promoting or suppressing replication of viruses has been aided by analyses of host cells that impose inherent blocks on viral replication. In this study, we show that primary human MDM, which are not permissive to IAV replication, fail to support virus particle formation. This defect is specific to primary human macrophages, since a human monocytic cell line differentiated to macrophage-like cells supports IAV particle formation. We further identified association between two viral transmembrane proteins, HA and M2, on the cell surface as a discrete assembly step, which is defective in MDM. Defective HA-M2 association and particle budding, but not virus release, in MDM are rescued by disruption of actin cytoskeleton, revealing a previously unknown, negative role for actin, which specifically targets an early step in the multistep IAV production. Overall, our study uncovered a host-mediated restriction of association between viral transmembrane components during IAV assembly.

scholarly journals Bovine CD18 Is Necessary and Sufficient To Mediate Mannheimia (Pasteurella) haemolytica Leukotoxin-Induced Cytolysis

2002 ◽  
Vol 70 (9) ◽  
pp. 5058-5064 ◽  
Author(s):  
M. S. Deshpande ◽  
T. C. Ambagala ◽  
A. P. N. Ambagala ◽  
M. E. Kehrli ◽  
S. Srikumaran
Keyword(s):  
Cell Surface ◽  
Surface Expression ◽  
Surface Proteins ◽  
Polymorphonuclear Neutrophils ◽  
Cell Surface Expression ◽  
Target Cells ◽  
Dependent Manner ◽  
Β Subunit ◽  
Concentration Dependent Manner ◽  
Necessary And Sufficient

ABSTRACT Leukotoxin (Lkt) secreted by Mannheimia (Pasteurella) haemolytica is an RTX toxin which is specific for ruminant leukocytes. Lkt binds to β2 integrins on the surface of bovine leukocytes. β2 integrins have a common β subunit, CD18, that associates with three distinct α chains, CD11a, CD11b, and CD11c, to give rise to three different β2 integrins, CD11a/CD18 (LFA-1), CD11b/CD18 (Mac-1), and CD11c/CD18 (CR4), respectively. Our earlier studies revealed that Lkt binds to all three β2 integrins, suggesting that the common β subunit, CD18, may be the receptor for Lkt. In order to unequivocally elucidate the role of bovine CD18 as a receptor for Lkt, a murine cell line nonsusceptible to Lkt (P815) was transfected with cDNA for bovine CD18. One of the transfectants, 2B2, stably expressed bovine CD18 on the cell surface. The 2B2 transfectant was effectively lysed by Lkt in a concentration-dependent manner, whereas the P815 parent cells were not. Immunoprecipitation of cell surface proteins of 2B2 with monoclonal antibodies specific for bovine CD18 or murine CD11a suggested that bovine CD18 was expressed on the cell surface of 2B2 as a heterodimer with murine CD11a. Expression of bovine CD18 and the Lkt-induced cytotoxicity of 2B2 cells were compared with those of bovine polymorphonuclear neutrophils and lymphocytes. There was a strong correlation between cell surface expression of bovine CD18 and percent cytotoxicity induced by Lkt. These results indicate that bovine CD18 is necessary and sufficient to mediate Lkt-induced cytolysis of target cells.

Interleukin-9 enhances interleukin-5 receptor expression, differentiation, and survival of human eosinophils

Blood ◽  
2000 ◽  
Vol 96 (6) ◽  
pp. 2163-2171 ◽  
Author(s):  
Abdelilah Soussi Gounni ◽  
Bernard Gregory ◽  
Esra Nutku ◽  
Fadi Aris ◽  
Koussih Latifa ◽  
...  
Keyword(s):  
Peripheral Blood ◽  
Messenger Rna ◽  
Receptor Expression ◽  
Cell Surface Expression ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Α Subunit ◽  
Human Eosinophil ◽  
Cd34 Cells ◽  
Interleukin 9

Interleukin-9 (IL-9) has been implicated in the pathogenesis of allergic disorders. To examine the interaction between IL-9 and eosinophils, we evaluated mature peripheral blood eosinophils for their expression of the specific α-subunit of the IL-9 receptor (IL-9R–α). The expression of IL-9R–α by human eosinophils was detected at the messenger RNA (mRNA) and protein levels by reverse transcriptase–polymerase chain reaction (RT-PCR), flow cytometry, and immunocytochemical analysis, respectively. Functional analyses demonstrated that recombinant human (rh)IL-9 inhibited in vitro peripheral blood human eosinophil apoptosis in a concentration-dependent manner. We then examined the role of IL-9 in eosinophil differentiation using the human cord blood CD34+cells and human promyelocytic leukemia cells (HL-60). The addition of IL-9 to CD34+ cells cultured in IL-3 and IL-5 enhanced eosinophil development, and IL-9 alone induced the expression of IL-5R–α. IL-9 also up-regulated the IL-5R–α chain cell surface expression during terminal eosinophil differentiation of the HL-60 cell line. Our findings suggest that IL-9 may potentiate in vivo eosinophil function by increasing their survival and IL-5–mediated differentiation and maturation. Taken together, these results suggest a mechanism by which IL-9 potentiates airway and tissue eosinophilia.

scholarly journals A Defect in Influenza A Virus Particle Assembly Specific to Primary Human Macrophages

2017 ◽  
Author(s):  
Sukhmani Bedi ◽  
Takeshi Noda ◽  
Yoshihiro Kawaoka ◽  
Akira Ono
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Cell Line ◽  
Influenza A Virus ◽  
Influenza A ◽  
Actin Polymerization ◽  
Monocytic Cell ◽  
Monocytic Cell Line ◽  
Particle Assembly ◽  
Human Macrophages

AbstractThe primary target of Influenza A virus (IAV) is epithelial cells in the respiratory tract. In contrast to epithelial cells, productive infection of most IAV strains is either blocked or highly inefficient in macrophages. The exact nature of the defect in IAV replication in human macrophages remains unknown. In this study, we showed that primary human monocyte-derived macrophages (MDM) are inefficient in IAV release even when compared to a monocytic cell line differentiated to macrophage-like cells, despite comparable levels of expression of viral glycoproteins at the plasma membrane. Correlative fluorescence scanning electron microscopy revealed that formation of budding structures at the cell surface is inefficient in MDM even though clustering of a viral glycoprotein, hemagglutinin (HA), is observed, suggesting that IAV particle assembly is blocked in human MDM. Using anin situproximity ligation assay, we further determined that association between HA and the viral ion channel protein M2 is defective at the plasma membrane of MDM. In contrast, HA and another glycoprotein neuraminidase (NA) associate with each other on the MDM surface efficiently. Notably, the defect in association between HA and M2 in MDM was reversed upon inhibition of actin polymerization by cytochalasin D. Altogether, these results suggest that HA-M2 association on the plasma membrane is a discrete step in the IAV assembly process, which is separable from the association between HA and NA and susceptible to suppression by actin cytoskeleton. Overall, our study revealed the presence of a cell-type-specific mechanism negatively regulating IAV assembly at the plasma membrane.ImportanceIdentification of host cell determinants promoting or suppressing replication of many viruses has been aided by analyses of host cells that impose inherent blocks on viral replication. In this study, we show that primary human MDM are not permissive to IAV replication due to a defect at the virus particle formation step. This defect is specific to primary human macrophages, since a human monocytic cell line differentiated to macrophage-like cells supports IAV particle formation. We further identified association between two viral transmembrane proteins, HA and M2, on the cell surface as a discrete assembly step, which is defective in MDM. Defective HA-M2 association in MDM is rescued by disruption of the actin cytoskeleton, revealing a previously unknown, negative role for actin polymerization, which is generally thought to play positive roles in IAV assembly. Overall, our study uncovered a host-mediated restriction of association between viral transmembrane components during IAV assembly.

scholarly journals Two sites on P-selectin (the lectin and epidermal growth factor-like domains) are involved in the adhesion of monocytes to thrombin-activated endothelial cells

1994 ◽  
Vol 303 (2) ◽  
pp. 619-624 ◽  
Author(s):  
J F Murphy ◽  
J L McGregor
Keyword(s):  
Endothelial Cells ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Mononuclear Cells ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Monocytic Cell ◽  
Monocytic Cell Line ◽  
Activated Platelets ◽  
Epidermal Growth

P-selectin, also known as GMP-140, PADGEM or CD62, is expressed on the surface of thrombin-activated platelets and endothelial cells (EC). It is a member of the selectin family of adhesion molecules that regulate leucocyte interactions with the blood vessel wall. In this study we have found that peptides derived from both the lectin (residues 19-34 and 51-61) and epidermal growth factor (EGF)-like (residues 127-139) domains inhibit the adhesion of peripheral blood mononuclear cells (PBMC), elutriated monocytes and a monocytic cell line (U937) to thrombin-activated EC. This inhibition occurred in a concentration-dependent manner and the peptide most active at the lowest concentrations was the one derived from the EGF-like motif (127-139). The scrambled forms of these peptides, identical in amino acid composition to the authentic peptides but with altered sequences, were not inhibitory. Thrombin-activated platelets supported adhesion of U937 cells and this adhesion was dramatically inhibited by the two peptides derived from the lectin-like domain (residues 19-34 and 51-61). All three peptides, when conjugated to BSA and coated on plastic plates, mediated U937 cell adhesion. This study shows, for the first time, that two sites on P-selectin, the lectin and EGF-like domains, are involved in the adhesion of monocytes to thrombin-activated EC.

Interleukin-9 enhances interleukin-5 receptor expression, differentiation, and survival of human eosinophils

Blood ◽  
2000 ◽  
Vol 96 (6) ◽  
pp. 2163-2171 ◽  
Author(s):  
Abdelilah Soussi Gounni ◽  
Bernard Gregory ◽  
Esra Nutku ◽  
Fadi Aris ◽  
Koussih Latifa ◽  
...  
Keyword(s):  
Peripheral Blood ◽  
Messenger Rna ◽  
Receptor Expression ◽  
Cell Surface Expression ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Α Subunit ◽  
Human Eosinophil ◽  
Cd34 Cells ◽  
Interleukin 9

Abstract Interleukin-9 (IL-9) has been implicated in the pathogenesis of allergic disorders. To examine the interaction between IL-9 and eosinophils, we evaluated mature peripheral blood eosinophils for their expression of the specific α-subunit of the IL-9 receptor (IL-9R–α). The expression of IL-9R–α by human eosinophils was detected at the messenger RNA (mRNA) and protein levels by reverse transcriptase–polymerase chain reaction (RT-PCR), flow cytometry, and immunocytochemical analysis, respectively. Functional analyses demonstrated that recombinant human (rh)IL-9 inhibited in vitro peripheral blood human eosinophil apoptosis in a concentration-dependent manner. We then examined the role of IL-9 in eosinophil differentiation using the human cord blood CD34+cells and human promyelocytic leukemia cells (HL-60). The addition of IL-9 to CD34+ cells cultured in IL-3 and IL-5 enhanced eosinophil development, and IL-9 alone induced the expression of IL-5R–α. IL-9 also up-regulated the IL-5R–α chain cell surface expression during terminal eosinophil differentiation of the HL-60 cell line. Our findings suggest that IL-9 may potentiate in vivo eosinophil function by increasing their survival and IL-5–mediated differentiation and maturation. Taken together, these results suggest a mechanism by which IL-9 potentiates airway and tissue eosinophilia.

scholarly journals Cell Surface Expression of 5-Hydroxytryptamine Type 3 Receptors Is Promoted by RIC-3

2005 ◽  
Vol 280 (23) ◽  
pp. 22502-22507 ◽  
Author(s):  
Aixin Cheng ◽  
Neil A. McDonald ◽  
Christopher N. Connolly
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Surface ◽  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
And Function ◽  
Type 3

RIC-3 has been identified as a molecule essential for the recruitment of functional nicotinic acetylcholine receptors composed of α7, but it exhibits inhibitory effects on α4β2 or α3β4 receptors. In this study, we investigated the role of RIC-3 in the recruitment of 5-hydroxytryptamine type 3A (5-HT3A) receptors to the cell surface. Although RIC-3 is not essential for the surface transport of 5-HT3A receptors, we found that its presence enhances both receptor transport and function in a concentration-dependent manner. RIC-3 is localized to the endoplasmic reticulum, as evidenced by co-localization with the chaperone molecule, binding protein (BiP). RIC-3 is not detected at significant levels on the cell surface when expressed alone or in the presence of 5-HT3A. RIC-3 and 5-HT3A show a low level interaction that is transient (<4 h). That RIC-3 can interact with an endoplasmic reticulum-retained 5-HT3A construct, combined with the transient interaction observed and lack of significant surface-expressed RIC-3, suggests that RIC-3 may play a role in 5-HT3A receptor folding, assembly, or transport to the cell surface.

Cell surface interactions in conjugation: Tetrahymena ciliary membrane vesicles

1984 ◽  
Vol 4 (4) ◽  
pp. 681-687
Author(s):  
B Love ◽  
M B Rotheim
Keyword(s):  
Cell Surface ◽  
Mating Type ◽  
Mammalian Cells ◽  
Membrane Vesicles ◽  
Surface Interactions ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Ciliary Membrane ◽  
Adhesion Sites ◽  
Cell Surface Interactions

Tetrahymena ciliary membrane vesicles are shown to interact with preconjugant cells in a mating type-specific way. When cells are treated with vesicles of a different mating type before mixing for conjugation, cell pairing is enhanced, and the normal prepairing period is partially eliminated. This enhancement is mating type specific since it is not observed after pretreatment of cells with vesicles of their own mating type. In contrast, when vesicles are added at the time of mixing of two starved cultures, cell pairing is delayed in a concentration-dependent manner. By varying the conditions, we demonstrated enhancement or inhibition, or both. These results are interpreted in terms of two independent interactions of cells with vesicles. We suggest that first, vesicles substitute for another cell in cell-cell prepairing interaction and second, vesicles compete for adhesion sites produced during the prepairing period. Finally, the data presented are summarized within a speculative framework that calls attention to potential analogies with hormone-receptor signaling in mammalian cells.

Multimerization of monocyte chemoattractant protein-1 is not required for glycosaminoglycan-dependent transendothelial chemotaxis

2001 ◽  
Vol 358 (3) ◽  
pp. 737-745 ◽  
Author(s):  
Simi ALI ◽  
Adrian C. V. PALMER ◽  
Sarah J. FRITCHLEY ◽  
Yvonne MALEY ◽  
John A. KIRBY
Keyword(s):  
Cell Surface ◽  
Fusion Protein ◽  
Radioligand Binding ◽  
Heparan Sulphate ◽  
Placental Alkaline Phosphatase ◽  
Monocytic Cell ◽  
Monocytic Cell Line ◽  
Monocyte Chemoattractant Protein 1 ◽  
Monocyte Chemoattractant ◽  
Monocyte Chemoattractant Protein

Chemokines interact with specific G-protein-coupled cell-surface receptors and with glycosaminoglycans (GAGs), such as heparan sulphate. Although chemokines often form multimers in solution, this process may be enhanced following interaction with GAGs on the cell surface, or within the extracellular matrix. However, the significance of multimerization for chemokine function remains controversial. In the present study, a fusion protein was prepared between the prototypical human CC chemokine, monocyte chemoattractant protein-1 (MCP-1; also known as CCL-2) and a large secreted placental alkaline phosphatase (SEAP) moiety. This fusion protein (MCP-1–SEAP) remained monomeric under conditions that promote oligomerization of the native chemokine. Radioligand binding showed that both native MCP-1 and MCP-1–SEAP competed for the same site on the surface of HEK-293 cells expressing the CCR2b chemokine receptor. The interaction between either chemokine species and endothelial cell surface GAGs was antagonized by the addition of the heparan sulphate-like molecule, heparin. Both MCP-1 and MCP-1–SEAP induced a Ca2+-flux in the THP-1 monocytic cell line, and were equally effective at promoting transendothelial chemotaxis of mononuclear immune cells, with maximal migration being produced by treatment with 12nM of either species. In each case this chemotactic response was almost completely antagonized by the addition of heparin. The importance of interaction between either native MCP-1 or MCP-1–SEAP and cell-surface GAGs for transcellular migration was demonstrated by the almost complete absence of leucocyte chemotaxis across monolayers of GAG-deficient mutant cells. In summary, this study shows that multimerization is neither necessary for, nor potentiates, the biological activity of MCP-1. However, the results do clearly demonstrate the importance of the interaction between MCP-1 and cell-surface heparan sulphate for transmonolayer leucocyte chemotaxis.

Adhesion of uric acid crystals to the surface of renal epithelial cells

2000 ◽  
Vol 278 (6) ◽  
pp. F989-F998 ◽  
Author(s):  
Rima M. Koka ◽  
Erick Huang ◽  
John C. Lieske
Keyword(s):  
Uric Acid ◽  
Epithelial Cells ◽  
Cell Surface ◽  
Hydrophobic Interactions ◽  
Calcium Phosphates ◽  
Apical Cell ◽  
Apical Surface ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Renal Tubular Cells

Adhesion of microcrystals that nucleate in tubular fluid to the apical surface of renal tubular cells could be a critical step in the formation of kidney stones, 12% of which contain uric acid (UA) either alone or admixed with calcium oxalates or calcium phosphates. UA crystals bind rapidly to monolayer cultures of monkey kidney epithelial cells (BSC-1 line), used to model the surface of the nephron, in a concentration-dependent manner. The urinary glycoproteins osteopontin, nephrocalcin, and Tamm-Horsfall glycoprotein had no effect on binding of UA crystals to the cell surface, whereas other polyanions including specific glycosaminoglycans blocked UA crystal adhesion. Specific polycations also inhibited adhesion of UA crystals and appeared to exert their inhibitory effect by coating cells. However, removal of anionic cell surface molecules with neuraminidase, heparitinase I, or chondroitinase ABC each increased UA crystal binding, and sialic acid-binding lectins had no effect. These observations suggest that hydrogen bonding and hydrophobic interactions play a major role in adhesion of electrostatically neutral UA crystals to renal cells, unlike the interaction of calcium-containing crystals with negatively charged molecules on the apical cell surface via ionic forces. After adhesion to the plasma membrane, subsequent cellular events could contribute to UA crystal retention in the kidney and the development of UA or mixed calcium and UA calculi.

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