ERβ in CD4+ T Cells Is Crucial for Ligand-Mediated Suppression of Central Nervous System Autoimmunity

Abstract

The development of therapies for multiple sclerosis targeting pathogenic T cell responses remains imperative. Previous studies have shown that estrogen receptor (ER) β ligands could inhibit experimental autoimmune encephalomyelitis. However, the effects of ERβ-specific ligands on human or murine pathogenic immune cells, such as Th17, were not investigated. In this article, we show that the synthetic ERβ-specific ligand 4-(2-phenyl-5,7-bis[trifluoromethyl]pyrazolo[1,5-a]pyrimidin-3-yl)phenol (PHTPP) reversed established paralysis and CNS inflammation, characterized by a dramatic suppression of pathogenic Th responses as well as induction of IL-10–producing regulatory CD4+ T cell subsets in vivo. Moreover, administration of PHTPP in symptomatic mice induced regulatory CD4+ T cells that were suppressive in vivo. PHTPP-mediated experimental autoimmune encephalomyelitis amelioration was canceled in mice with ERβ-deficient CD4+ T cells only, indicating that expression of ERβ by these cells is crucial for the observed therapeutic effect. Importantly, synthetic ERβ-specific ligands acting directly on CD4+ T cells suppressed human and mouse Th17 cells, downregulating Th17 cell signature gene expression and expanding IL-10–producing T cells among them. TGF-β1 and aryl hydrocarbon receptor activation enhanced the ERβ ligand-mediated expansion of IL-10–producing T cells among Th17 cells. In addition, these ERβ-specific ligands promoted the induction and maintenance of Foxp3+ T regulatory cells, as well as their in vitro suppressive function. Thus, ERβ-specific ligands targeting pathogenic Th17 cells and inducing functional regulatory cells represent a promising subset of therapeutic agents for multiple sclerosis.

ERβ-Dependent Direct Suppression of Human and Murine Th17 Cells and Treatment of Established Central Nervous System Autoimmunity by a Neurosteroid

“…In the same study, DHEA was also reported to suppress IL-6 expression by the microglia cell line BV2 (30). Notwithstanding, recent studies by our group revealed that ERb-selective ligands treat established EAE and ongoing Th17 responses (12). Thus, we tested whether DHEA-mediated suppression of established Th17 responses required ERb expression in CD4 + T cells.…”

“…Spinal cords were fixed in 10% (v/v) saline-buffered formalin and embedded in paraffin. The 7-mm paraffin-embedded sections were stained with H&E to evaluate spinal cord infiltration, as described previously (12) …”

“…RNA extraction, quantification, and cDNA synthesis was performed as previously described (12). The sequences of RT-PCR primers used for mRNA relative expression analysis in this study were designed using the Primer 3 …”

“…Another important study also revealed that AhR activation leads to ER-mediated estrogen signaling through direct association of agonist-activated AhR with ERb (32). In addition, our studies recently showed that ERb ligand-mediated expansion of IL-10-producing T cells among Th17 cells depends on AhR activation (12). To test whether AhR activation plays a role in the expansion of IL-10-and/or of IL-17/IL-10-producing CD4 + T cells by DHEA, we added an AhR antagonist to Th17 maintenance cultures.…”

Sex Hormones in Acquired Immunity and Autoimmune Disease

“…Further, DHEA-treated PBMCs from patients with relapsing remitting multiple sclerosis (RR-MS) exhibited decreased IFN-γ, IL-17, IL-4, and IL-2 responses but preserved IL-10. Thus such compounds, which suppress pro-inflammatory cells and expand regulatory subsets, could be useful as therapeutic agents ( 93 ).…”