Lactosylceramide Mediates the Expression of Adhesion Molecules in TNF- and IFN -stimulated Primary Cultured Astrocytes

Here we have investigated how lactosylceramide (LacCer) modulates gene expression of adhesion molecules in TNF-${\alpha}$ and IFN ${\gamma}$ (CM)-stimulated astrocytes. We have observed that stimulation of astrocytes with CM increased the gene expression of ICAM-1 and VCAM-1. D-Threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP) and N-butyldeoxynojirimycin (NBDNJ), inhibitors of glucosylceramide synthase (GLS) and LacCer synthase (galactosyltransferase, GalT-2), inhibited the gene expression of ICAM-1 and VCAM-1 and activation of their gene promoter induced by CM, which were reversed by exogenously supplied LacCer. Silencing of GalT-2 gene using its antisense oligonucleotides also attenuated CM-induced ICAM-1 and VCAM-1 expression, which were reversed by LacCer. PDMP treatment and silencing of GalT-2 gene significantly reduced CM-induced luciferase activities in NF-${\kappa}B$, AP-1, GAS, and STAT-3 luciferase vectors-transfected cells. In addition, LacCer reversed the inhibition of NF-${\kappa}B$ and STAT-1 luciferase activities by PDMP. Taken together, our results suggest that LacCer may play a crucial role in the expression of ICAM-1 and VCAM-1 via modulating transcription factors, such as NF-${\kappa}B$, AP-1, STAT-1, and STAT-3 in CM-stimulated astrocytes.