L-selectin function is required for beta 2-integrin-mediated neutrophil adhesion at physiological shear rates in vivo

Abstract

In vivo interactions between neutrophils and endothelial cells (EC) follow a multistep process involving two distinct neutrophil adhesion receptors. L-selectin, constitutively functional on resting neutrophils, mediates an activation-independent primary interaction resulting in rolling along the venular wall. Subsequent activation of rolling neutrophils induces upregulation and functional activation of beta 2-integrins (CD11/CD18) leading to firm attachment. Based on previous findings we hypothesized that, under shear force, rolling may be essential for successful neutrophil-EC recognition. Here we report results of our studies of human neutrophil behavior in interleukin (IL)-1-activated rabbit mesentery venules, an interaction that requires both L-selectin and beta 2-integrins. Rolling of human neutrophils is L-selection mediated; it was strongly reduced by monoclonal antibody inhibition or enzymatic removal of L-selectin. Furthermore, activation induced L-selectin shedding and, in a dose- and time-dependent fashion, rendered neutrophils unable to recognize inflamed EC despite expression of active beta 2-integrins, which promoted adhesion in vitro. Neutrophils activated for 5 min or longer lost most of their ability to roll. However, 1-3 min after activation, rolling was reduced (not abolished), and cells that were still able to roll displayed a significant tendency for a CD18-dependent transition from rolling to sticking. The whole sequence of events, rolling, sticking, and transendothelial migration, could be observed if an extravascular chemotactic stimulus was applied by superfusing mesenteries with leukotriene B4. Under such conditions, sticking and emigration was blocked when rolling was inhibited by enzymatic removal of L-selectin. Our results indicate that primary neutrophil interaction with inflamed EC through the L-selectin is a prerequisite for neutrophil function at physiological shear rates in vivo.

Paradoxical attenuation of leukocyte rolling in response to ischemia- reperfusion and extracorporeal blood circulation in inflamed tissue

“…Similarly, Nonaka and colleagues (33) observed in a retinal ischemia-reperfusion model that the maximum number of rolling leukocytes can be significantly reduced by ischemic preconditioning. Finally, Wang and co-workers (40) showed that preconditioning with morphine increases shedding from the neutrophil surface of gp100 MEL14 , the murine analog to human L-selectin and a key adhesion molecule involved in the initial steps of leukocyte rolling (39). On the basis of our present observation, we speculate that, in analogy to these earlier reports, "inflammatory preconditioning" may play an important role in our studies.…”

A role for endogenous histamine in interleukin‐8‐induced neutrophil infiltration into mouse air‐pouch: investigation of the modulatory action of systemic and local dexamethasone

“…migration in response to soluble gradients of chemoattractants) action (Rot, 1993), and, that endothelial cells have specific binding sites for this cytokine (Rot, 1992;Tanaka et al, 1993). According to this recently proposed model, the involvement of a co-factor(s) which facilitates leucocyte rolling on the endothelial wall (Rot, 1992), is a fundamental requisite for a subsequent firm adhesion via P2-integrins (Lawrence & Springer, 1991;Von Andrian et al, 1992). Previous studies have suggested that IL-8-induced PMN infiltration in the rat peritoneal cavity may require the presence of resident mast cells (Ribeiro et al, 1991), and that a genetic strain of mice deficient of this cell type have an impaired response to IL-8 (reported in Rot, 1993).…”

The Transmembrane Domains of L-selectin and CD44 Regulate Receptor Cell Surface Positioning and Leukocyte Adhesion under Flow

“…CD44 is involved in many physiological processes, including lymphocyte activation, adhesion, and proliferation (12). There is also increasing evidence that CD44 and L-selectin contribute to tumor metastasis (13,14).Under many physiologic conditions, L-selectin initiates the first step of the adhesion cascade (15,16). While surveying the vascular bed, rapidly flowing leukocytes face the challenge to establish contact to static ligands of the endothelial layer at high velocities.…”

“…Under many physiologic conditions, L-selectin initiates the first step of the adhesion cascade (15,16). While surveying the vascular bed, rapidly flowing leukocytes face the challenge to establish contact to static ligands of the endothelial layer at high velocities.…”