Iron Deficiency Aggravates Hepatic Inflammation via Endoplasmic Reticulum Stress-Driven NF-κB Pathway Activation in Suckling Piglets

Iron deficiency (ID) imposes a significant health burden on infants and suckling piglets, yet its impact on hepatic inflammatory injury remains poorly defined. This study combined in vivo and in vitro models to investigate the underlying mechanisms. In piglets, iron deficiency triggered hepatic oxidative stress by inducing a redox imbalance and suppressing the core Nrf2/HO-1 antioxidant signaling pathway. Histopathological examination revealed structural abnormalities in ID piglet livers, including disorganized hepatic cords, cytoplasmic vacuolation, hydropic degeneration, and mononuclear inflammatory cell infiltration. Transmission electron microscopy further showed shrunk nuclear envelopes, reduced numbers of rough endoplasmic reticulum (RER), and dilated RER cisternae in hepatocytes from ID piglets. Mechanistically, ID activated endoplasmic reticulum stress (ERS) and the PERK/IRE1α branches of the unfolded protein response. RNA-seq transcriptomic analysis demonstrated significant dysregulation of immune-related pathways, accompanied by elevated pro-inflammatory cytokines (e.g.,interleukin-1 beta, IL-1β, tumor necrosis factor-alpha, TNF-α) and decreased anti-inflammatory cytokines (e.g., interleukin 4, IL-4, interleukin-10, IL-10). Central to this inflammatory response was the activation of the TLR4/NF-κB pathway, evidenced by upregulation of MyD88 and increased phosphorylation of IκBα and NF-κB p65. In vitro, deferoxamine (DFO)-induced ID in hepatocytes consistently recapitulated the key features of this phenotype, including the activation of ERS/ UPR and the TLR4/NF-κB signaling pathway. Critically, pharmacological inhibition of ERS by 4-phenylbutyrate (4-PBA) attenuated DFO-induced NF-κB activation and restored pro-/anti-inflammatory cytokine balance. In conclusion, these findings demonstrate that ID exacerbates hepatic inflammation through ERS-mediated activation of NF-κB pathway, providing novel mechanistic insights into liver injury associated with ID.