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

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 in
flammatory 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 cyto
kine 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.