Estrogen protects against postpartum Concanavalin A-induced hepatitis by promoting intrahepatic CD4⁺CD25⁺ Treg expansion through activation of the PI3K/Akt signaling pathway in HBV-Tg mice

Abstract Introduction Postpartum hepatitis flares have been commonly described, but the specific mechanism is unclear. Objectives Our objective was to explore estrogen’s role in postpartum hepatitis flares in HBV transgenic mice. Methods The numbers of intrahepatic CD4+CD25+Foxp3+ regulatory T cells...

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Main Authors: Chuanlu Xu, Yao Su, Wenjing Lu, Jiaqi Dong, Luyao Wang, Yabing Mi, Xinrui Jia, Wenqi Lv, Shengyu Wu, Yuanhui Jia, Hao Ying
Format: Article
Language:English
Published: BMC 2025-07-01
Series:Virology Journal
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Online Access:https://doi.org/10.1186/s12985-025-02879-4
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Summary:Abstract Introduction Postpartum hepatitis flares have been commonly described, but the specific mechanism is unclear. Objectives Our objective was to explore estrogen’s role in postpartum hepatitis flares in HBV transgenic mice. Methods The numbers of intrahepatic CD4+CD25+Foxp3+ regulatory T cells (Tregs) and the levels of the inhibitory cytokine IL-10 were determined in concanavalin A (Con A)-injected mice with and without estrogen injection postpartum. The role of intrahepatic CD4+CD25+Foxp3+Tregs in suppressing immune responses was investigated by systemically depleting intrahepatic CD25+ cells in mice treated with an anti-CD25 mAb. We employed the PI3K inhibitor LY294002 to investigate the function of the PI3K/Akt pathway in regulating the suppressive activity of intrahepatic CD4+CD25+Foxp3+Tregs in vivo. Results A higher percentage of CD4+CD25+Foxp3+Tregs accumulated in the liver with increasing physiological E2 levels during pregnancy, declined sharply by day 7 postpartum. We discovered that estrogen regulates the proliferation and activation of intrahepatic CD4+CD25+Foxp3+ Tregs via the PI3K/Akt signaling cascade and participates in hepatitis immune regulation. Furthermore, E2 administration postpartum increased intrahepatic CD4+CD25+Foxp3+Tregs and inhibitory cytokine IL-10, which inhibit the immune clearance of CD8+ T cells and NK cells along with decreased cytotoxic cytokine IFN-γ and TNF-α levels. Conclusion Estrogen protects against postpartum Con A-induced hepatitis by promoting intrahepatic CD4⁺CD25⁺ Treg expansion through activation of the PI3K/Akt signaling pathway in HBV-Tg mice.
ISSN:1743-422X