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Estrogen replacement therapy-induced neuroprotection against brain ischemia-reperfusion injury involves the activation of astrocytes via estrogen receptor β.

Ma Y, Guo H, Zhang L, Tao L, Yin A, Liu Z, Li Y, Dong H, Xiong L, Hou W - Sci Rep (2016)

Bottom Line: And 10 nM E2, DPN or E2+MPP (ERα antagonist), but not PPT or E2+PHTPP (ERβ antagonist), significantly reduced neuronal apoptosis following the subjection of astrocyte and neuronal cocultures to OGD-R.We also found that either 50 μg/kg E2 or 8 mg/kg DPN replacement (3 weeks) significantly increased GFAP expression and reduced GCI-induced neuronal apoptosis in hippocampal CA1 region of ovariectomized mice.These results indicate that estrogen-induced neuroprotection against ischemia-reperfusion injury involves activation of astrocytes via ERβ.

View Article: PubMed Central - PubMed

Affiliation: Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China.

ABSTRACT
The incidence of ischemic stroke is significantly increased in postmenopausal women. However, the neuroprotective effects of estrogen replacement therapy (ERT) against stroke remain controversial, and the role of astrocytes in ERT has rarely been explored. In this study, we investigated the effects of estrogen and selective estrogen receptor (ER) agonists on astrocytes activation and neuronal apoptosis in mice under conditions of cell culture oxygen and glucose deprivation and reperfusion (OGD-R), and global cerebral ischemia (GCI). We demonstrated that hippocampal astrocytes primarily express ERβ. In astrocytes, 2.5-20 nM 17β-estradiol (E2) or 10 nM DPN (ERβ agonist) not 10 nM PPT (ERα agonist), significantly increased GFAP expression. And 10 nM E2, DPN or E2+MPP (ERα antagonist), but not PPT or E2+PHTPP (ERβ antagonist), significantly reduced neuronal apoptosis following the subjection of astrocyte and neuronal cocultures to OGD-R. We also found that either 50 μg/kg E2 or 8 mg/kg DPN replacement (3 weeks) significantly increased GFAP expression and reduced GCI-induced neuronal apoptosis in hippocampal CA1 region of ovariectomized mice. These results indicate that estrogen-induced neuroprotection against ischemia-reperfusion injury involves activation of astrocytes via ERβ. Thus, the discovery and design of astrocyte-selective ERβ modulators may offer a new strategy for ERT of ischemic stroke.

No MeSH data available.


Related in: MedlinePlus

E2 and DPN replacement up-regulated GFAP protein expression in the mice hippocampus (n = 5).(A) Data are shown as the mean ± S.D; **p < 0.05 vs. Con group; #p < 0.05 and ##p < 0.01 vs. OVX group. (B) Cropped gels and blots showing the expression of GFAP in 50 μg/kg E2 and 8 mg/kg DPN replacement group. The samples derive from the same experiment and that gels/blots were processed in parallel. Full-length blots/gels are presented in Supplementary Fig. 4.
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f5: E2 and DPN replacement up-regulated GFAP protein expression in the mice hippocampus (n = 5).(A) Data are shown as the mean ± S.D; **p < 0.05 vs. Con group; #p < 0.05 and ##p < 0.01 vs. OVX group. (B) Cropped gels and blots showing the expression of GFAP in 50 μg/kg E2 and 8 mg/kg DPN replacement group. The samples derive from the same experiment and that gels/blots were processed in parallel. Full-length blots/gels are presented in Supplementary Fig. 4.

Mentions: The results of western blot analyses corresponded to those of the immunofluorescence assay. As shown in Fig. 5, the expression levels of GFAP protein in the OVX group were significantly decreased compared with those of the Con group (**p < 0.01), and 50 μg/kg E2 and 8 mg/kg DPN replacement significantly increased GFAP protein expression (#p < 0.05 and ##p < 0.01 vs. the OVX group). No significant difference was observed between the E2 and DPN groups.


Estrogen replacement therapy-induced neuroprotection against brain ischemia-reperfusion injury involves the activation of astrocytes via estrogen receptor β.

Ma Y, Guo H, Zhang L, Tao L, Yin A, Liu Z, Li Y, Dong H, Xiong L, Hou W - Sci Rep (2016)

E2 and DPN replacement up-regulated GFAP protein expression in the mice hippocampus (n = 5).(A) Data are shown as the mean ± S.D; **p < 0.05 vs. Con group; #p < 0.05 and ##p < 0.01 vs. OVX group. (B) Cropped gels and blots showing the expression of GFAP in 50 μg/kg E2 and 8 mg/kg DPN replacement group. The samples derive from the same experiment and that gels/blots were processed in parallel. Full-length blots/gels are presented in Supplementary Fig. 4.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4759820&req=5

f5: E2 and DPN replacement up-regulated GFAP protein expression in the mice hippocampus (n = 5).(A) Data are shown as the mean ± S.D; **p < 0.05 vs. Con group; #p < 0.05 and ##p < 0.01 vs. OVX group. (B) Cropped gels and blots showing the expression of GFAP in 50 μg/kg E2 and 8 mg/kg DPN replacement group. The samples derive from the same experiment and that gels/blots were processed in parallel. Full-length blots/gels are presented in Supplementary Fig. 4.
Mentions: The results of western blot analyses corresponded to those of the immunofluorescence assay. As shown in Fig. 5, the expression levels of GFAP protein in the OVX group were significantly decreased compared with those of the Con group (**p < 0.01), and 50 μg/kg E2 and 8 mg/kg DPN replacement significantly increased GFAP protein expression (#p < 0.05 and ##p < 0.01 vs. the OVX group). No significant difference was observed between the E2 and DPN groups.

Bottom Line: And 10 nM E2, DPN or E2+MPP (ERα antagonist), but not PPT or E2+PHTPP (ERβ antagonist), significantly reduced neuronal apoptosis following the subjection of astrocyte and neuronal cocultures to OGD-R.We also found that either 50 μg/kg E2 or 8 mg/kg DPN replacement (3 weeks) significantly increased GFAP expression and reduced GCI-induced neuronal apoptosis in hippocampal CA1 region of ovariectomized mice.These results indicate that estrogen-induced neuroprotection against ischemia-reperfusion injury involves activation of astrocytes via ERβ.

View Article: PubMed Central - PubMed

Affiliation: Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China.

ABSTRACT
The incidence of ischemic stroke is significantly increased in postmenopausal women. However, the neuroprotective effects of estrogen replacement therapy (ERT) against stroke remain controversial, and the role of astrocytes in ERT has rarely been explored. In this study, we investigated the effects of estrogen and selective estrogen receptor (ER) agonists on astrocytes activation and neuronal apoptosis in mice under conditions of cell culture oxygen and glucose deprivation and reperfusion (OGD-R), and global cerebral ischemia (GCI). We demonstrated that hippocampal astrocytes primarily express ERβ. In astrocytes, 2.5-20 nM 17β-estradiol (E2) or 10 nM DPN (ERβ agonist) not 10 nM PPT (ERα agonist), significantly increased GFAP expression. And 10 nM E2, DPN or E2+MPP (ERα antagonist), but not PPT or E2+PHTPP (ERβ antagonist), significantly reduced neuronal apoptosis following the subjection of astrocyte and neuronal cocultures to OGD-R. We also found that either 50 μg/kg E2 or 8 mg/kg DPN replacement (3 weeks) significantly increased GFAP expression and reduced GCI-induced neuronal apoptosis in hippocampal CA1 region of ovariectomized mice. These results indicate that estrogen-induced neuroprotection against ischemia-reperfusion injury involves activation of astrocytes via ERβ. Thus, the discovery and design of astrocyte-selective ERβ modulators may offer a new strategy for ERT of ischemic stroke.

No MeSH data available.


Related in: MedlinePlus