The PEN5 Epitope Identifies an Oligodendrocyte Precursor Cell Population and Pilocytic Astrocytomas

Abstract

PEN5 is a sulfated polylactosamine carbohydrate epitope first described in a subpopulation of mature natural killer cells. Here we report that it is also expressed in a developmentally regulated fashion in human and rat central nervous systems and that its protein carrier is P-selectin glycoprotein ligand-1 (PSGL-1) , a ligand for selectins. In rat neural primary cultures , PEN5 is transiently and selectively expressed by oligodendrocyte precursor cells and marks the transition from proliferative to postmitotic stages. In concordance , in human central nervous system tumors , PEN5 is observed in a subset of oligodendrogliomas and in all pilocytic astrocytomas, a class of tumor of uncertain histogenesis. These data suggest that PEN5-PSGL-1 plays a role in the differentiation of oligodendrocytes and that pilocytic astrocytomas are likely to result from a dysregulation occurring in oligodendrocyte precursor cells at the crucial stage of exit from the cell cycle. (Am J Pathol 1999, 155:1261-1269)Many developmentally important cell-cell interaction and cell differentiation processes are shared by the immune and nervous systems. Indeed, several cell surface molecules are expressed by subpopulations of both neural and immune cells. This is the case of growth factors, interleukins and their receptors,

Biosynthesis of HNK-1 Glycans on O-Linked Oligosaccharides Attached to the Neural Cell Adhesion Molecule (NCAM)

“…This is probably because N-glycans are more extended from the polypeptide backbone than O-glycans. On the other hand, PSGL-1 glycoprotein containing numerous O-glycans has an extended rodlike structure and has been shown to have sulfated N-acetyllactosamines, presumably on the O-glycans (55,56). These combined results strongly suggest that MSD of NCAM may not display as preferable a conformation for enzymes that synthesize O-glycans as the conformation of PSGL-1.…”

Anti-Human Olig2 Antibody as a Useful Immunohistochemical Marker of Normal Oligodendrocytes and Gliomas

“…Pilocytic astrocytomas and a subset of glioblastomas are known to share some markers with oligodendrocyte progenitors such as NG2, PEN5, platelet-derived growth factor receptor ␣ (PDGFR␣). 34,35 Therefore, comparative study of Olig1/2 with these markers on gliomas is very interesting, and remains to be elucidated. Recently, a new concept, glioblastoma with oligodendroglial components, has been proposed based on accumulated evidence that a subset of glioblastoma includes areas with oligodendroglial features, or a subset of oligodendroglioma acquires the morphological features of glioblastoma during malignant progression.…”

Glycosulfopeptides with O-Glycans Containing Sialylated and Polyfucosylated Polylactosamine Bind with Low Affinity to P-selectin

“…The polylactosamine sequences on PSGL-1 may also serve as a precursor to other modifications. Sulfated polylactosamine chains on PSGL-1, recognized as the PEN5 epitope have been reported on PSGL-1 on some natural killer cells and in the human and rat central nervous systems (44,45). It is also possible that the sialylated FIG.…”