Posttreatment with Ospemifene Attenuates Hypoxia- and Ischemia-Induced Apoptosis in Primary Neuronal Cells via Selective Modulation of Estrogen Receptors

Abstract

Stroke and perinatal asphyxia have detrimental effects on neuronal cells, causing millions of deaths worldwide each year. Since currently available therapies are insufficient, there is an urgent need for novel neuroprotective strategies to address the effects of cerebrovascular accidents. One such recent approach is based on the neuroprotective properties of estrogen receptors (ERs). However, activation of ERs by estrogens may contribute to the development of endometriosis or hormone-dependent cancers. Therefore, in this study, we utilized ospemifene, a novel selective estrogen receptor modulator (SERM) already used in dyspareunia treatment. Here, we demonstrated that posttreatment with ospemifene in primary neocortical cell cultures subjected to 18 h of hypoxia and/or ischemia followed by 6 h of reoxygenation has robust neuroprotective potential. Ospemifene partially reverses hypoxia- and ischemia-induced changes in LDH release, the degree of neurodegeneration, and metabolic activity. The mechanism of the neuroprotective actions of ospemifene involves the inhibition of apoptosis since the compound decreases caspase-3 overactivity during hypoxia and enhances mitochondrial membrane potential during ischemia. Moreover, in both models, ospemifene decreased the levels of the proapoptotic proteins BAX, FAS, FASL, and GSK3β while increasing the level of the antiapoptotic protein BCL2. Silencing of specific ERs showed that the neuroprotective actions of ospemifene are mediated mainly via ESR1 (during hypoxia and ischemia) and GPER1 (during hypoxia), which is supported by ospemifene-evoked increases in ESR1 protein levels in hypoxic and ischemic neurons. The results identify ospemifene as a promising neuroprotectant, which in the future may be used to treat injuries due to brain hypoxia/ischemia.

Amorfrutin B Compromises Hypoxia/Ischemia-induced Activation of Human Microglia in a PPARγ-dependent Manner: Effects on Inflammation, Proliferation Potential, and Mitochondrial Status

“…BCL2 is widely recognized as a mitochondrial protein, and its function is usually related to apoptosis and/or autophagy (Wnuk and Kajta 2017 ). Intriguingly, upregulation of anti-apoptotic BCL2 has been detected in Alzheimer’s and Huntington’s diseases patients, as well as in models of brain hypoxia and ischemia (Satou et al 1995 ; Karlnoski et al 2007 ; Sassone et al 2013 ; Wnuk et al 2020 , 2021a , Wnuk, Przepiórska et al 2021 ; Przepiórska et al 2023 ; Pietrzak et al 2023 ). Since adult human brain express more BCL2 in microglia than in neurons (Merry et al 1994 ), and hypoxia/ischemia increase BCL2 expression in brain tissue (Chen et al 1997 ), one can assume that this increase is dependent mainly on microglia-localized BCL2.…”

Posttreatment with PaPE-1 Protects from Aβ-Induced Neurodegeneration Through Inhibiting the Expression of Alzheimer’s Disease-Related Genes and Apoptosis Process That Involves Enhanced DNA Methylation of Specific Genes

“…However, Bcl2 gene hypermethylation and intact BCL2 protein levels suggest other PaPE-1-dependent mechanisms to control Aβ-induced apoptosis. BCL2 upregulation has been unexpectedly detected in response to hypoxia, ischemia, and neurodegenerative diseases and was explained as a compensatory mechanism preventing neurons from acute or chronic injury [ 21 , 22 , 33 , 35 , 57 – 59 ]. BCL2 dysregulation may be related to the dual role of autophagy during neurodegeneration, depending on its interaction with the process of apoptosis and abilities to bind and inhibit Ca 2+ flux of inositol-1,4,5-trisphosphate receptors (IP3Rs) and ryanodine receptors (RyRs).…”

“…Fluoro-Jade C staining was used to assess the level of degenerating neurons as previously described [ 33 , 35 ]. To conduct the staining, a stock solution with a concentration of 0.01% was prepared by diluting the Fluoro-Jade C in distilled water.…”