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Biochim Biophys Acta Mol Cell Res. 2018 Jan;1865(1):57-66. doi: 10.1016/j.bbamcr.2017.09.019. Epub 2017 Sep 28.

Nerve/glial antigen (NG) 2 is a crucial regulator of intercellular adhesion molecule (ICAM)-1 expression.

Author information

1
Institute for Clinical & Experimental Surgery, Saarland University, 66421 Homburg/Saar, Germany.
2
Medical Biochemistry and Molecular Biology, Saarland University, 66421 Homburg/Saar, Germany.
3
Department of Molecular Physiology, CIPMM (Center for Integrative Physiology and Molecular Medicine), Saarland University, 66421 Homburg/Saar, Germany.
4
Institute for Clinical & Experimental Surgery, Saarland University, 66421 Homburg/Saar, Germany. Electronic address: emmanuel.ampofo@uks.eu.

Abstract

The proteoglycan nerve/glial antigen (NG) 2 is expressed on multiple cell types and mediates cell proliferation and migration. However, little is known about its function in gene regulation. In this study, we demonstrate that in pericytes and glioblastoma cells intercellular adhesion molecule (ICAM)-1, an essential protein for leukocyte adhesion and transmigration, underlies a NG2-dependent expression. As shown by flow cytometry, Western blot analysis and quantitative real-time polymerase chain reaction (qRT-PCR), silencing of NG2 in human placenta-derived pericytes increased the expression of ICAM-1. Pathway analyses revealed that this is mediated by extracellular-regulated-kinases (ERK) 1/2 signaling. Moreover, leukocyte adhesion to NG2 siRNA-treated pericytes was significantly enhanced when compared to scrambled (scr) siRNA-treated control cells. In vivo, we detected increased ICAM-1 protein levels in the retina of mice lacking NG2 expression. To exclude that this novel mechanism is pericyte-specific, we additionally analyzed the expression of ICAM-1 in dependency of NG2 in two glioblastoma cell lines. We found that A1207 and M059K cells exhibit an inverse expression pattern of NG2 and ICAM-1. Finally, downregulation of NG2 in A1207 cells significantly increased ICAM-1 expression. Taken together, these findings indicate that NG2 may represent a promising target for the modulation of ICAM-1-mediated immune responses.

KEYWORDS:

ERK1/2; Glioblastoma; ICAM-1; Leukocyte-transmigration; NG2; Pericytes

PMID:
28964848
DOI:
10.1016/j.bbamcr.2017.09.019
[Indexed for MEDLINE]
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