Showing papers by "Betty Soliven published in 1999"
TL;DR: P38α is the mediator in cer-induced OLG apoptosis and that cer- induced IKir inhibition may contribute to the sustained activation of p38α in OLGs, which is found to affect OLG survival and activation of MAPK members.
Abstract: Sphingolipid products such as ceramide (cer), sphingosine (sph), and sphingosine-1-phosphate (SPP) are implicated in the regulation of cell growth and apoptosis. We have recently shown that cer, sph, and SPP differentially modulate ionic events in cultured oligodendrocytes (OLGs). Cer but not sph or SPP inhibits the inward rectifier ( I Kir) in OLGs. To further investigate the role of sphingolipid products in OLGs, we studied the effect of cer, sph, and SPP on OLG survival and on the regulation of mitogen-activated protein kinases (MAPKs). We found that cer, sph, and SPP differentially modulate OLG survival and activation of MAPK members. Cer causes OLG apoptosis, sph causes OLG lysis, and SPP does not affect OLG survival. Cer induces a preferential activation of p38α, whereas sph and SPP induce a preferential activation of extracellular signal-regulated kinase 2 (ERK2) in OLGs. In addition, the effect of cer on p38α activity is mimicked by the inhibition of I Kir with Ba2+. In contrast, exposure to cer results in increased activity of ERK2 but not of p38α in astrocytes. Cer-induced OLG apoptosis is attenuated by a p38 inhibitor, SB203580, and by expression of a p38α dominant negative mutant. We conclude that p38α is the mediator in cer-induced OLG apoptosis and that cer-induced I Kir inhibition may contribute to the sustained activation of p38α in OLGs.
62 citations