Raloxifene and tamoxifen reshape the immunometabolic phenotype of TLRs-activated macrophages through AEBS inhibition and lysosomal stress

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Macrophages are key effectors of innate immune responses and infection control, relying on Toll-like receptors (TLRs) to sense pathogens and adopt immunometabolic anti-infective phenotypes. Raloxifene (RAL) and tamoxifen (TAM) are selective estrogen receptor modulators (SERMs) known to reprogram macrophage inflammatory responses via estrogen receptor-independent mechanisms, including NRF2 activation. Although drug repurposing approaches have highlighted anti-infective properties of these compounds, supporting host-directed mechanisms, the upstream targets and immune consequences of RAL and TAM in macrophages remain undefined. Here, we investigated the biological relevance and molecular determinants of SERM-mediated immune activity in TLR-activated macrophages. Our results show that RAL and TAM modulate inflammatory cytokine expression induced by TLR7/8, TLR4, and TLR2 stimulation. Specifically, these SERMs enhance IL 1β maturation, despite reducing proIl1b mRNA levels, and increase TNF α production, while restraining IL 6 expression. Notably, IL 6 repression is more pronounced with RAL and correlates with sustained NRF2 pathway engagement, suggesting a drug-specific immunoregulatory profile. Furthermore, RAL and TAM influence cytokine regulation through cholesterol-pathway remodeling consistent with AEBS inhibition, which was associated with PI3K-NRF2 activation and NRF2-related immunometabolic adaptation. In parallel, RAL and TAM promote lysosomal perturbations, leading to the regulation of proIl1b and Tnfa mRNA levels and to cathepsin B-associated caspase-1 activation and IL1β production. Cathepsin B inhibition further enhances NRF2-target gene responses, suggesting functional crosstalk between lysosomal and NRF2-associated pathways. Overall, these findings indicate that RAL and TAM elicit an integrated immunometabolic reshaping of macrophage inflammatory phenotypes, through cholesterol-pathway remodeling and lysosomal stress, supporting SERMs as host-directed chemotherapeutic agents.

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