Ultrathin, highly organized functionalized alkylthiol monolayers were applied as model substrates for cell growth and protein adsorption studies. The aim of this approach was to improve the understanding molecular surface determinants required adhesion-dependent proliferation using well-controlled chemistry. Carboxyl- methyl-terminated on gold used monitor Swiss 3T3 fibroblast adhesion, spreading, growth. Stress fiber focal contact formation determined by immunostaining actin filaments...

The frequent inflammatory responses to implanted medical devices are puzzling in view of the inert and nontoxic nature most biomaterials. Because implant surfaces spontaneously adsorb host proteins, this proteinaceous film is probably important subsequent attraction phagocytes. In fact, earlier we found that acute experimental polyethylene terephthalate implants mice require precedent adsorption one particular protein, fibrinogen. present investigations were aimed at defining molecular...

The interaction of leukocyte integrin α_Mβ₂ (CD11b/CD18, Mac-1) with fibrinogen has been implicated in the inflammatory response by contributing to adhesion endothelium and subsequent transmigration. Previously, it demonstrated that a peptide, P1, corresponding residues 190–202 γ-chain fibrinogen, binds blocks receptor Asp¹⁹⁹ within P1 is important activity. We have demonstrated, however, double mutation Asp¹⁹⁹-Gly²⁰⁰ Gly-Ala recombinant...

We have shown previously that treatment of human aortic endothelial cells (HAECs) with minimally modified low-density lipoprotein (MM-LDL) induces monocyte but not neutrophil binding. This binding was mediated by E-selectin, P-selectin, vascular cell adhesion molecule-I, or intercellular suggesting an alternative monocyte-specific molecule. now show moncytic α4β1 integrins mediate to MM-LDL-treated cells. present data the expression connecting segment-1 (CS-1) domain fibronectin (FN) is...

Plasma fibronectin readily changes shape in response to environmental conditions which may, turn, lead differential expression of its multiple functional sites. To test this possibility, the two type III modules within cell binding domain was assessed with monoclonal antibodies (mAb). Utilizing proteolytic and recombinant fragments plasma fibronectin, epitopes recognized by mAbIII-9 mAbIII-10 were localized ninth tenth (RGD-containing) repeats respectively. Both mAb inhibited adhesion...

The binding of fibrinogen to membrane glycoprotein GPIIb-IIIa on activated platelets leads platelet aggregation. This interaction results in conformational changes as evidenced by the expression receptor-induced sites, RIBS, epitopes which are expressed bound but not free ligand. In present study, two RIBS have been localized. One sequence resides at gamma 112-119 and is recognized mAb 9F9; second RGDF A alpha 95-98 155B16. These also exposed adsorption onto a plastic surface digestion...

The broad recognition specificity exhibited by integrin α(M)β2 (Mac-1, CD11b/CD18) has allowed this adhesion receptor to play innumerable roles in leukocyte biology, yet we know little about how and why binds its multiple ligands. Within α(M)β2, the α(M)I-domain is responsible for integrin's multiligand binding properties. To identify motif, screened peptide libraries spanning sequences of many known protein ligands also selected phage display. Analyses >1400 nonbinding peptides derived from...

The leukocyte integrin α_Mβ₂ is a highly promiscuous receptor capable of binding multitude unrelated ligands. To understand the molecular basis for broad ligand recognition α_Mβ₂, inter-integrin chimera was created. In chimeric integrin, βd-α5 loop-α5 helix segment comprised residues Lys²⁴⁵–Arg²⁶¹ from α_MI domain inserted into framework α_Lβ₂. construct expressed in HEK 293 cells, and ability...

The leukocyte integrin alphaMbeta2 (Mac-1) is a multiligand receptor that mediates range of adhesive reactions leukocytes during the inflammatory response. This binds coagulation protein fibrinogen providing key link between thrombosis and inflammation. However, mechanism by which remains unknown. Previous studies indicated model in two gammaC domain sequences, P1 (gamma190-202) P2 (gamma377-395), serve as binding sites cannot fully account for recognition integrin. Here, using surface...

Fibrinogen is a ligand for leukocyte integrin αMβ2 (CD11b/CD18, Mac-1) and mediates adhesion migration of leukocytes during the immune-inflammatory responses. The binding site resides in γC, constituent subdomain D-domain fibrinogen. sequence γ383−395 (P2-C) γC was implicated as major αMβ2. It unknown why on can bind to immobilized fibrinogen presence high concentrations soluble plasma. In this study, we have investigated accessibility We found that αMβ2-binding cryptic identified mechanism...

Leukocyte migration is the hallmark of inflammation, and integrin αMβ2 its ligand fibrinogen (Fg) are key participants in this cellular response. Cells expressing wild-type or mutant Fg derivatives have been used to dissect molecular requirements for receptor–ligand pair mediate cell migration. The major conclusions that (a) Fg, D fragment, P1 P2 recognition peptides support a chemotactic response; (b) when I domain αL was replaced with αM, chimeric receptor supported Fg; however, αM...

We report an atomic force microscopy (AFM) study of fibrinogen molecules and fibrin fibers with resolution previously achieved only in few electron images. Not are all objects triads, but the peripheral D regions resolved into two subdomains, apparently corresponding to βC γC domains. The conformational analysis a large population on mica revealed most energetically favorable conformations characterized by bending angles ∼100 160 degrees. Computer modeling experimental images showed that AFM...

Platelet factor 4 (PF4) is one of the most abundant cationic proteins secreted from α-granules activated platelets. Based on its structure, PF4 was assigned to CXC family chemokines and has been shown have numerous effects myeloid leukocytes. However, receptor for remains unknown. Here, we demonstrate that induces leukocyte responses through integrin Mac-1 (αMβ2, CD11b/CD18). Human neutrophils, monocytes, U937 monocytic HEK293 cells expressing strongly adhered immobilized in a...

The currently available antithrombotic agents target the interaction of platelet integrin αIIbβ3 (GPIIb-IIIa) with fibrinogen during aggregation. Platelets also bind fibrin formed early thrombus growth. It was proposed that inhibition platelet-fibrin interactions may be a necessary and important property antagonists; however, mechanisms by which binds are uncertain. We have previously identified γ370-381 sequence (P3) in γC domain as fibrin-specific binding site for involved adhesion...

Abstract: LL-37, a cationic antimicrobial peptide, has numerous immune-modulating effects. However, the identity of receptor that mediates responses in immune cells remains uncertain. We have recently demonstrated LL-37 interacts with α M I-domain integrin β 2 (Mac-1), major on surface myeloid cells, and induces migratory response Mac-1-expressing monocyte/macrophages as well activation Mac-1 neutrophils. Here, we show its C-terminal derivative supported strong adhesion various including...

Macrophage fusion resulting in the formation of multinucleated giant cells occurs a variety chronic inflammatory diseases, yet mechanism responsible for initiating this process is unknown. Here, we used live cell imaging to show that actin-based protrusions at leading edge initiate macrophage fusion. Phase-contrast video microscopy demonstrated majority events, short (∼3 µm) between two closely apposed initiated fusion, but occasionally observed long (∼12 µm). Using macrophages isolated from...

CCN1 (cysteine-rich 61) and CCN2 (connective tissue growth factor) are factor-inducible immediate-early gene products found in atherosclerotic lesions, restenosed blood vessels, healing cutaneous wounds. Both CCN proteins have been shown to support cell adhesion induce migration through interaction with integrin receptors. Recently, we identified alphaMbeta2 as the major receptor mediating monocyte that alphaMI domain binds specifically both proteins. In present study, demonstrated activated...