Abstract
Salmonellosis, caused by Salmonella enterica serovar Typhimurium, is a significant global
threat. Host immunity limits bacterial replication by inducing hepcidin, which degrades
ferroportin, reducing iron transfer. However, this boosts macrophage iron storage, aiding
intracellular pathogens like Salmonella. Mice lacking ferritin heavy chain (FTH1) in myeloid cells
suffer worsened Salmonella infection. Nuclear receptor co-activator 4 (NCOA4) regulates iron
release via FTH1 degradation during low iron, but its role in salmonellosis is unclear. Here, we
reveal that myeloid NCOA4 deficiency augments spleen iron levels and increases cellular iron
accumulation, oxidative stress, and ferroptosis in bone marrow-derived macrophages. This
deficiency also increases susceptibility to Salmonella-induced colitis in mice. Mechanistically,
NCOA4 suppresses oxidative stress by directly binding to the E3 ubiquitin ligase Kelch-like
ECH-associated protein 1 (KEAP1) and stabilizing the antioxidant transcription factor nuclear
factor-erythroid 2-related factor 2 (NRF2). Activation of NRF2 protects myeloid NCOA4 knockout
mice from Salmonella-induced colitis. Antioxidant Tempol and myeloid cell-targeted curcumin
offer protection against colitis in myeloid NCOA4-deficient mice. A low iron diet and ferroptosis
inhibition also mitigate the heightened colitis in these mice. Overexpression of myeloid cell-
specific NCOA4 confers protection against Salmonella-induced colitis via upregulating NRF2
signaling. Serum iron was reduced in myeloid NCOA4-overexpressing mice, but not in NCOA4-
deficient mice. Targeted serum metabolomics analysis revealed that many lipids were
decreased in myeloid NCOA4-deficient mice, while several of them were increased in myeloid
NCOA4-overexpressing mice. Together, this study not only advances our understanding of
NCOA4/KEAP1/NRF2/ferroptosis axis but also paves the way for novel myeloid cell-targeted
therapies to combat salmonellosis.