Estrogen Receptor-Dependent Regulation of Dendritic Cell Development and Function.

Area of Science:

• Immunology
• Endocrinology
• Cell Biology

Background:

• Sex-based differences in immune responses influence susceptibility to infectious diseases, autoimmunity, and cancer.
• Sex steroid hormones, particularly estrogens, are implicated in regulating innate immune cell biology, especially dendritic cells (DCs).
• Estrogen receptors (ERs) are expressed on DC progenitor cells and mature subsets, suggesting a role for estrogen in immune regulation.

Purpose of the Study:

• To review and highlight evidence for estrogen receptor alpha (ERα)-dependent regulation of dendritic cell (DC) development and function.
• To elucidate the role of estrogen signaling in sex-specific immune responses mediated by DCs.
• To explore the impact of estrogen on specific DC subsets, including conventional DCs (cDCs) and plasmacytoid DCs (pDCs).

Main Methods:

• Review of recent literature on estrogen's role in DC biology.
• Analysis of in vitro models of DC differentiation (GM-CSF-induced and Flt3L-induced).
• Investigation of estrogen signaling's effect on DC subset development, cytokine production, and T lymphocyte activation.

Main Results:

• ERα activation by estrogen is essential for the development of specific CD11c+ CD11bint Ly6cneg cells (related to cDC2 subset) and their ability to activate naive CD4+ T lymphocytes.
• Estrogen signaling, alongside GM-CSF, promotes early Irf-4 expression in macrophage-DC progenitors, driving differentiation into IRF-4hi CD11c+ CD11bint Ly6cneg cells.
• ERα signaling enhances the development of conventional DCs (cDCs) and plasmacytoid DCs (pDCs), increasing their pro-inflammatory cytokine production and type I interferon (IFN) production in response to TLR stimulation.

Conclusions:

• Estrogen signaling, via ERα, plays a significant role in regulating the development and functional responses of key dendritic cell subsets (cDC2, cDC, pDC).
• This estrogen-dependent regulation of DCs contributes to sex differences in immune proficiency, such as the enhanced type I IFN production by women's pDCs.
• Emerging evidence supports estrogen signaling as a critical factor in both mouse and human DC biology, impacting adaptive immunity and disease susceptibility.