Caveolin expression is essential for NMDA‐mediated ERK1/2 phosphorylation in cultured neurons

Abstract

Ischemic preconditioning (PC) is a phenomenon whereby various stimuli reduce the vulnerability of the brain to subsequent lethal ischemia. Although the endogenous signaling mechanisms remains unknown, previous work suggests that NMDA receptor (NMDAR) mediated signaling plays a critical role in neuronal PC. Because Src is involved in NMDAR signaling, we hypothesized that neuronal PC is dependent upon transient phosphorylation of Src, the Src scaffolding protein Cav-1, and ERK1/2. Immunoblot analysis of OGDSL (sublethal oxygen glucose deprivation)-treated or NMDA-stimulated neurons revealed a significant enhancement in phosphorylated Cav-1 (P-Cav-1), P-Src, P-ERK1/2, and P-p38 (P<0.05). Cav-1-siRNA treated neurons (72 hr) had reduced Cav-1 protein expression and attenuated NMDA-mediated Src and ERK1/2 phosphorylation (P-ERK1/2) as assessed by immunoblot and immunofluorescence microscopy. NMDA or OGDSL- exposure to neurons from Cav-1 null mice failed to enhance P-Src or P-ERK1/2. In summary, neither Src or ERK1/2 were activated in Cav-1 siRNA treated neurons or neurons from Cav-1 null mice after exposure to NMDA or OGDSL suggesting that Cav-1 expression is required for NMDA and OGDSL-mediated activation of Src and ERK1/2, two pro-survival kinases involved in neuronal preconditioning. (Supported by NIH)