The Binding of Type I Collagen to Lymphocyte Function-associated Antigen (LFA) 1 Integrin Triggers the Respiratory Burst of Human Polymorphonuclear Neutrophils

Abstract

The transduction pathways depending on the ␣ L ␤ 2 integrin do not involve a G protein (ruled out by the use of cholera and pertussis toxins), whereas the cytoskeleton was found to participate in the process, as evidenced by inhibition by cytochalasin B. After collagen stimulation, cytoplasmic inositol trisphosphate and calcium ion increased sharply for less than 2 min. The use of the inhibitors staurosporine and calphostin C demonstrated that protein kinase C was involved. Evaluation of the activity of this enzyme showed that, upon stimulation of PMN with collagen I, it was translocated to plasma membrane.Acrylamide gel electrophoresis of the protein bands corresponding to the integrin ␣ L ␤ 2 , followed by immunoblotting using monoclonal antibodies to phosphotyrosine, permitted us to demonstrate that, prior to stimulation by type I collagen, there was no phosphorylation, whereas after stimulation, both ␣ L and ␤ 2 chains were stained by anti-phosphotyrosine antibodies. The adhesion of PMN to pepsinized type I collagen triggered tyrosine phosphorylation of the ␤ 2 chain of the integrin, without stimulating O 2 . production by these cells, whereas their stimulation by complete type I collagen induced the tyrosine phosphorylation of both ␣ L and ␤ 2 subunits. The tyrosine phosphorylation of both integrin subunits during transduction of stimuli is a heretofore undescribed phenomenon that may correspond to a new system of transmembrane communication.Type I collagen, a major component of the extra cellular matrix, promotes the adhesion of a variety of cells in solid tissues, influencing many processes such as proliferation, differentiation, migration, and cell shape changes (1). Several receptor molecules have been demonstrated as promoting the adhesion to type I collagen. Among these receptors, some belong to the family of integrins, for instance ␣ 1 ␤ 1 , ␣ 2 ␤ 1 , and ␣ 3 ␤ 1 (2). On the other hand, some types of mobile cells also interact with collagens, for instance polymorphonuclear neutrophils (PMN), 1 a variety of leukocytes circulating in blood, capable of crossing the vascular wall in order to invade the inflamed tissues and to participate in defenses against bacteria or foreign molecules through their property of phagocytosis. In several previous papers, we demonstrated that PMN and type I collagen do interact and began to describe their interactions (3-5).Purified type I collagen is able to bind to PMN in vitro. This binding is followed by the stimulation of some main functions of PMN, such as emission of pseudopods, secretion of lytic enzymes, and liberation of superoxide. We demonstrated that the stimulation of PMN by collagen occurs through two sequences of the ␣ 1 (I) chain, both located in the C-terminal region of the molecules, an RGD sequence corresponding to residues 915-917, and a DGGRYY sequence corresponding to residues 1034 -1039, located at the C-terminal extremity of the chain. The type I collagen molecule, either fibrillar or denatured, is active, whereas pepsinized collagen, lacking the C...

Human Blood Monocytes Interact with Type I Collagen Through αxβ2 Integrin (CD11c-CD18, gp150-95)

“…During these processes, cells exchange various messages, principally through cytokine production, some of them being triggered by interactions with ECM proteins, that in turn lead to the maintenance of an inflammatory state or, on the contrary, to the restoration of physiological conditions. Previous works of our laboratory have shown that type I collagen was able to deeply influence the metabolism of cells involved in these processes, in the case of fibroblasts (22,23) as well as PMNs (3)(4)(5)(6). In this work, we present new evidences that type I collagen interactions with monocytes are critical events involved in these processes.…”

“…When monocytes were incubated with anti-CD11a, anti-CD11b, or anti-lymphocyte (used as additional control) Abs, which are blocking Abs (6), no inhibition of collagen I-induced O 2 Ϫ production was noticed. In the same way, the mAb anti-CD29 (␤ 1 subunit) had no effect.…”

Characterization of Mannheimia (Pasteurella) haemolytica leukotoxin interaction with bovine alveolar macrophage β2 integrins

“…A number of studies have demonstrated that "outside in" LFA-1 activation and signaling are dependent on conformational changes induced in the I-domain as a result of interaction with a ligand [35,38,48]. These activation events, including phosphorylation of exposed tyrosine residues on the CD18 cytoplasmic tail and intracellular calcium elevation [16], have also been shown to be elicited in bovine leukocytes after exposure to LktA [22]. Stabilizing the I-domain in a closed conformation with a variety of statin-derived and non-statin small molecule compounds has been shown to allosterically inhibit ligand interaction and activation of LFA-1 [25,53,54].…”

Neutrophils responded to immobilized lipopolysaccharide in the absence of lipopolysaccharide-binding protein

“…It has been reported that type I collagen binds to CD11a/CD18 molecules, and that it triggers a respiratory burst in human neutrophils [42]. Although the binding sites have not been identified, type IV collagen also binds to neutrophils, causing inhibition of fMLP-induced, phorbol myristate acetate-induced, or type I collagen-induced activation of the cells [43].…”