Inhibition of ferroptosis or NF-κB signalling protects LPS-induced TIMP1 overexpression-induced cell damage

Acute lung injury (ALI) is characterized by excessive inflammation and oxidative stress, with ferroptosis emerging as a critical pathological mechanism. However, the role of tissue inhibitor of metalloproteinases 1 (TIMP1) in regulating ferroptosis during ALI remains unclear.

Lipopolysaccharide (LPS)-induced ALI models were established in vivo and in vitro. TIMP1 expression was modulated using siRNA and overexpression approaches. Ferroptosis-related indicators, including lipid peroxidation, intracellular iron levels, and the expression of GPX4 and SLC7A11, were assessed by biochemical assays and qRT-PCR. The involvement of the TLR4/NF-κB signalling pathway was evaluated using pharmacological inhibitors and co-immunoprecipitation analysis.

TIMP1 expression was significantly upregulated in LPS-induced ALI models. TIMP1 knockdown markedly reduced lipid peroxidation levels (∼45% decrease), intracellular Fe²⁺ accumulation (∼38% reduction), and restored GPX4 and SLC7A11 expression (P < 0.01), indicating suppression of ferroptosis. Mechanistically, TIMP1 was found to interact with TLR4, enhancing its stability and promoting NF-κB activation, as evidenced by increased p65 phosphorylation (∼2.3-fold). Inhibition of TLR4 or NF-κB abrogated TIMP1-induced ferroptotic responses.

TIMP1 promotes ferroptosis in ALI through activation of the TLR4/NF-κB signalling pathway. Targeting TIMP1 may represent atherapeutic strategy for mitigating ferroptosis-associated lung injury.