Estrogen-mediated neuroprotection against β-amyloid toxicity requires expression of estrogen receptor α or β and activation of the MAPK pathway

Authors


Address correspondence and reprint requests to Dr Jennifer Fitzpatrick, Oregon Health Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97201, USA. E-mail: fretlanj@ohsu.edu

Abstract

It is well documented that estrogen can activate rapid signaling pathways in a variety of cell types. These non-classical effects of estrogen have been reported to be important for cell survival after exposure to a variety of neurotoxic insults. Since direct evidence of the ability of the estrogen receptors (ERs) α and/or β to mediate such responses is lacking, the hippocampal-derived cell line HT22 was stably transfected with either ERα (HTERα) or ERβ (HTERβ). In HTERα and HTERβ cells, but not untransfected cells, an increase in ERK2 phosphorylation was measured within 15 min of 17β-estradiol treatment. The ER antagonist ICI 182, 780 (1 µm) and the MEK inhibitor, PD98059 (50 µm) blocked this increase in ERK2 phosphorylation. Treatment of HT22, HTERα and HTERβ cells with the β-amyloid peptide (25–35) (10 µm) resulted in a significant decrease in cell viability. Pre-treatment for 15 min with 10 nm 17β-estradiol resulted in a 50% increase in the number of living cells in HTERα and HTERβ cells, but not in HT22 cells. Finally, ICI 182, 780 and PD98059 prevented 17β-estradiol-mediated protection. This study demonstrates that both ERα and ERβ can couple to rapid signaling events that mediate estrogen-elicited neuroprotection.

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