Human Endomucin

Abstract

Endomucin is a typical sialomucin that we recently identified on the surface of mouse endothelial cells and on putative hematopoetic clusters of the dorsal aorta in the embryo. We have generated a panel of monoclonal antibodies (mAbs) against the extracellular part of human endomucin and polyclonal antibodies against the cytoplasmic part. Using immunohistochemistry endomucin was specifically detected on endothelial cells of blood and lymphatic vessels of all analyzed human tissues. In addition, the polyclonal antibodies stained the epithelium of the epidermis as well as epithelial and myoepithelial cells of the eccrine and apocrine glands in the skin. This nonendothelial staining could only be seen with a subset of mAbs if the staining procedure was amplified. Although high endothelial venules (HEVs) were not significantly stained with mAbs against endomucin, the polyclonal antibodies clearly detected endomucin on HEVs in lymphatic organs of the mouse and human, suggesting HEV-specific glycosylation affecting recognition by the mAbs. Indeed, endomucin isolated from human and mouse lymphoid organs carried the MECA-79 epitope that defines a set of L-selectin ligands on HEVs called peripheral node addressins. We conclude that human and mouse endomucin are endothelial sialomucins with the potential to function as L-selectin ligands.

Generation of nephron progenitor cells and kidney organoids from human pluripotent stem cells

“…Those cells were presumably derived from SIX2-negative population which accounted for 10~20% of cells at the NPC stage, and could be collecting duct cells, pericytes, endothelial cells, smooth muscle cells, fibroblasts or others according to published studies 12,28,29 . Our recent unpublished results showed CDH1+AQP2+ tubules (characteristic of connecting tubules and collecting ducts 25 ) and PDGFRβ+ (characteristic of pericytes 26 ), endomucin+ (characteristic of endothelial cells 27 ), or α-SMA+ (characteristic of myofibroblasts 26 ) interstitial cells in the organoids (Supplementary Fig. 1, unpublished data generated by R.M.…”

Nepmucin, a novel HEV sialomucin, mediates L-selectin–dependent lymphocyte rolling and promotes lymphocyte adhesion under flow

“…Of these, the two with the higher molecular weight (75 and 95 kD) were decorated with L-selectin–reactive sugar chains carrying the MECA-79 epitope, which binds L-selectin. PNAd components with an apparent molecular size of ∼90 kD have been reported to be comprised of multiple sialomucins ( 36 ), including CD34 ( 11 , 12 ) and endomucin ( 13 , 14 ). The presence of a PNAd component of 75 kD has also been reported in the mouse LN ( 17 ).…”

“…Some of these have been cloned. These molecules include glycosylation-dependent cell adhesion molecule 1 (GlyCAM-1) ( 10 ), CD34 ( 11 , 12 ), endomucin ( 13 , 14 ), and podocalyxin ( 15 ). Of these, CD34, endomucin, and podocalyxin are broadly distributed in vascular endothelial cells in various organs, but L-selectin–reactive glycoforms of these sialomucins are seen in LN HEVs only, demonstrating the importance of tissue-specific posttranslational glycosylation events in LN HEVs for the generation of functional PNAd.…”

Endoglycan, a Member of the CD34 Family, Functions as an L-selectin Ligand through Modification with Tyrosine Sulfation and Sialyl Lewis x

“…These include GlyCAM-1 (mouse), CD34 (mouse and human), podocalyxin (human), MAdCAM-1 (mouse and human). Recently, endomucin (mouse and human) has been added to this list of candidates (6). All of these ligands are sialomucin in nature, containing a predominance of O-linked carbohydrate chains.…”