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An oestrogen membrane receptor participates in estradiol actions for the prevention of amyloid‐β peptide 1−40 ‐induced toxicity in septal‐derived cholinergic SN56 cells
Author(s) -
Marin Raquel,
Guerra Borja,
Morales Araceli,
Díaz Mario,
Alonso Rafael
Publication year - 2003
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.2003.01767.x
Subject(s) - neuroprotection , western blot , confocal microscopy , receptor , chemistry , intracellular , antibody , biology , microbiology and biotechnology , medicine , endocrinology , biochemistry , pharmacology , immunology , gene
Although oestrogen [17β‐estradiol (E2)]‐related neuroprotection has been demonstrated in different models, the involvement of non‐classical oestrogen receptors (ERs) remains unexplored. Using the SN56 cholinergic cell line, we present evidence indicating that an ER associated with the plasma membrane participates in oestrogen‐dependent inhibition of cell death induced by amyloid‐β peptide (Aβ) toxicity. Similarly to E2 alone, a 15‐min exposure to estradiol‐horseradish peroxidase (E‐HRP) significantly reduced Aβ‐induced cell death. This effect was decreased by the ER antagonist ICI 182,780 as well as by MC‐20 antibody directed to a region neighbouring the ligand‐binding domain of ERα. Using confocal microscopy on unpermeabilized SN56 cells exposed to MC‐20 antibody, we identified a protein at the plasma membrane level. Western blot analysis of purified SN56 cell membrane fractions using MC‐20 antibody revealed the presence of one band with the same electrophoretic mobility as intracellular ERα. Using conjugated forms of the steroid, E‐HRP and E2 conjugated to bovine serum albumin‐FITC, we demonstrated by confocal microscopy that SN56 cells contain surface binding sites for E2. Binding of both conjugates was blocked by pre‐incubation with E2 and decreased by either ICI 182,780 or MC‐20 antibody in a concentration‐dependent manner. Thus, a membrane‐related ER that shares some structural homologies with ERα may participate in oestrogen‐mediated neuroprotection.