Dermal Microvascular Endothelial Cells Express the 180-kDa Macrophage Mannose Receptor In Situ and In Vitro

Abstract

Expression of the 180-kDa mannose receptor (MR) is mainly found on cells of the macrophage lineage. MR mediates the uptake of micro-organisms and host-derived glycoproteins. We demonstrate that endothelium of the human skin in situ and dermal microvascular endothelial cells (DMEC) in vitro expressed MR at both the protein and mRNA levels. In contrast, HUVEC were consistently negative for MR expression. DMEC internalized dextran as well as Escherichia coli by the way of MR into acidic phagosomes, only a few of which fused with CD63- and lysosomal-associated membrane glycoprotein-2-positive lysosomes. This contrasts with the situation in monocyte-derived dendritic cells, where almost all of the MR-Ag complexes reached CD63- and lysosomal-associated membrane glycoprotein-2-positive compartments, indicating differences in the phagolysosomal fusion rate between DMEC and dendritic cells. In conclusion, DMEC express functional MR, a finding that corroborates a role of skin endothelium in Ag capture/clearing.

Candida albicans Triggers Activation of Distinct Signaling Pathways to Establish a Proinflammatory Gene Expression Program in Primary Human Endothelial Cells

“…According to our expression analysis (data not shown) and in line with an earlier report (47), dectin-1, the myeloid cell-expressed major receptor for fungal ␤-glucan, is not expressed by ECs thus excluding a role in Candidainduced endothelial signaling. Furthermore, the mannose receptor, another C-type lectin receptor, is absent in HUVEC (48). Thus, neither C-type lectin receptors nor TLR2 and TLR4 appear to be responsible for C. albicans-induced gene expression in our EC model.…”

Gastrin-releasing peptide (GRP) induces angiogenesis and the specific GRP blocker 77427 inhibits tumor growth in vitro and in vivo

“…Many differences have been reported between endothelial cells derived from the macrovasculature and the microvasculature (Groger et al, 2000;Salcedo et al, 2000;Otto et al, 2001) and angiogenic potential in response to GRP seems to be another one of them. Since new blood vessels sprout from the microvasculature, the lack of angiogenic response in HUVECs is not surprising.…”

Receptor-mediated endocytosis of immune complexes in rat liver sinusoidal endothelial cells is mediated by FcγRIIb2

“…33 Immunohistological studies performed on human placental and skin epithelia have, however, shown that endothelial cells express generally Fc␥RII but not Fc␥RIII. [33][34][35][36] In particular, fetal endothelial cells in human placenta have been shown to express a single type of Fc␥R, namely, Fc␥RIIb2. 37 Hunziker and Mellman 38 showed that Fc␥RIIb2 transfected into polarized cells is capable of mediating transcytosis of IgG.…”