Estrogen Receptor (ER)-α36 Is Involved in Estrogen- and Tamoxifen-Induced Neuroprotective Effects in Ischemic Stroke Models

PLoS One. 2015 Oct 20;10(10):e0140660. doi: 10.1371/journal.pone.0140660. eCollection 2015.

Abstract

The neuroprotection by estrogen (E2) and tamoxifen is well documented in experimental stroke models; however, the exact mechanism is unclear. A membrane-based estrogen receptor, ER-α36, has been identified. Postmenopausal-levels of E2 act through ER-α36 to induce osteoclast apoptosis due to a prolonged activation of the mitogen-activated protein kinase (MAPK)/extracellular signal-related kinase (ERK) signaling. We hypothesized that ER-α36 may play a role in the neuroprotective activities of estrogen and tamoxifen. Here, we studied ER-α36 expression in the brain, as well as its neuroprotective effects against oxygen and glucose deprivation (OGD) in PC12 cells. We found that ER-α36 was expressed in both rat and human brain. In addition, OGD-induced cell death was prevented by l nmol/L 17β-estradiol (E2β). E2β activates the MAPK/ERK signaling pathway in PC12 cells under basal and OGD conditions by interacting with ER-α36 and also induces ER-α36 expression. Low-dose of tamoxifen up-regulated ER-α36 expression and enhanced neuronal survival in an ovariectomized ischemic stroke model. Furthermore, low-dose of tamoxifen enhanced neuroprotective effects by modulating activates or suppress ER-α36. Our results thus demonstrated that ER-α36 is involved in neuroprotective activities mediated by both estrogen and tamoxifen.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / metabolism
  • Brain Ischemia / metabolism*
  • Brain Ischemia / prevention & control
  • Disease Models, Animal
  • Estrogen Receptor alpha / metabolism*
  • Estrogens / therapeutic use*
  • Humans
  • Neuroprotective Agents / therapeutic use*
  • PC12 Cells
  • Rats
  • Stroke / metabolism*
  • Stroke / prevention & control
  • Tamoxifen / therapeutic use*

Substances

  • Estrogen Receptor alpha
  • Estrogens
  • Neuroprotective Agents
  • estrogen receptor alpha 36, human
  • Tamoxifen

Grants and funding

This work was supported by the National Natural Science foundation of China (No. 30570225, No. 30970353, No. 81071009 and No. 1271412), International S&T Cooperation Project of the Ministry of S&T of China (No. 2010DFR30850), The People’s Livelihood S&T Project, Bureau of S&T of Dalian (No. 2010E11SF008, 2011E12SF030), the Scientific Research Foundation for Returned Overseas Chinese Scholars, State Education Ministry, and the Science and Technology Development Plan Project of Jilin Province, China.