title: Estrogen receptor subtypes alpha and beta contribute to neuroprotection and increased Bcl-2 expression in primary hippocampal neurons.
abstract: Estrogen receptor (ER) mediated neuroprotection has been demonstrated in both in vitro and in vivo model systems. However, the relative contribution by either ER subtype, ERalpha or ERbeta, to estrogen-induced neuroprotection remains unresolved. To address this question, we investigated the impact of selective ER agonists for either ERalpha, PPT, or ERbeta, DPN, to prevent neurodegeneration in cultured hippocampal neurons exposed to excitotoxic glutamate. Using three indicators of neuronal viability and survival, we demonstrated that both the ERalpha selective agonist PPT and the ERbeta selective agonist DPN protected hippocampal neurons against glutamate-induced cell death in a dose-dependent manner, with the maximal response occurring at 100 pM. Further analyses showed that both PPT and DPN enhanced Bcl-2 expression in hippocampal neurons, with an efficacy comparable to their neuroprotective capacity. Collectively, the present data indicate that activation of either ERalpha or ERbeta can promote neuroprotection in hippocampal neurons, suggesting that both receptor subtypes could be involved in estrogen neuroprotection. As ERbeta is highly expressed in the brain and has little or no expression in the breast or uterus, discovery and design of ERbeta selective molecules could provide a strategy for activating the beneficial effects of estrogen in the brain without activating untoward effects of estrogen in reproductive organs.
authors.affiliation: Department of Molecular Pharmacology and Toxicology, School of Pharmacy, University of Southern California, Pharmaceutical Sciences Center, 1985 Zonal Avenue, Los Angeles, CA 90089-9121, USA.
authors.forename: Liqin
authors.initials: L
authors.lastname: Zhao
authors.forename: Tzu-Wei
authors.initials: TW
authors.lastname: Wu
authors.forename: Roberta Diaz
authors.initials: RD
authors.lastname: Brinton
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D019610:Cytoprotection / Q000187:drug effects; D045166:Estradiol Congeners / Q000494:pharmacology* / Q000627:therapeutic use; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D004967:Estrogens / Q000378:metabolism / Q000494:pharmacology; D005260:Female; D005333:Fetus; D018698:Glutamic Acid / Q000378:metabolism; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D009410:Nerve Degeneration / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology*; D009498:Neurotoxins / Q000037:antagonists & inhibitors*; D009570:Nitriles / Q000494:pharmacology; D010636:Phenols; D011247:Pregnancy; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000187:drug effects* / Q000378:metabolism; D011720:Pyrazoles / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011960:Receptors, Estrogen / Q000819:agonists / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology; D011422:Propionates
chemical_list: D045166:Estradiol Congeners; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D004967:Estrogens; D018698:Glutamic Acid; D018696:Neuroprotective Agents; D009498:Neurotoxins; D009570:Nitriles; D010636:Phenols; D019253:Proto-Oncogene Proteins c-bcl-2; D011720:Pyrazoles; D011960:Receptors, Estrogen; C486182:2,3-bis(4-hydroxyphenyl)-propionitrile; D011422:Propionates; C486184:4,4',4''-(4-propyl-((1)H)-pyrazole-1,3,5-triyl) tris-phenol