Von Willebrand factor receptor GPIbα is expressed by human factor XIIIa-positive dermal dendrocytes and is upregulated by mast cell degranulation

Abstract

GPIbα, a glycoprotein component of the GPIb-IX-V complex, serves as a platelet membrane receptor that mediates adhesion to yon Willebrand factor normally present in the vascular subendothelium. Recent data have demonstrated that GPIbα is not restricted to platelets, but is also expressed by endothelium in vitro. In this study, we describe the expression and distribution of GPIbα in normal adult and neonatal human skin. GPIbα is present, as detected by immunohistochemistry, on endothelial cells and on highly dendritic cells localized within the perivascular space, dermal- epidermal junction, and reticular dermis. By dual-labeling immunofluorescence and confocal microscopy, GPIbα-positive cells within the dermal interstitium are demonstrated to represent factor XIIIa-positive dermal dendrocytes. In organ cultures of neonatal human foreskin, mast cell degranulation induced by either substance P or compound 48/80 resulted in transiently increased GPIbα expression by dermal dendrocytes. Because the GPIbIX-V complex plays a part in regulating hemostasis and may be important for cellular interactions with extracellular matrix molecules, these data provide additional insight into the potential function of FXIIIa-positive dermal dendrocytes in skin remodeling and repair.