Sex-specific differences of amlexanox in a mouse model for atherosclerosis and MASLD

Inhibitor‑κB kinase epsilon (IKKε) is a non‑canonical IκB kinase involved in NF‑κB signaling and type I interferon responses. We recently demonstrated sex‑dependent effects of IKKε deletion on atherosclerosis and metabolic dysfunction‑associated steatotic liver disease (MASLD), with male knockout mice showing protection against both diseases, while female mice exhibited exacerbated inflammatory and metabolic disturbances. These divergent outcomes were linked to differential effects on inflammatory pathways and lipid metabolism. To evaluate the therapeutic potential of pharmacological IKKε inhibition, we treated wild type mice with established atherosclerotic plaques and hepatic steatosis - induced by PCSK9 gain‑of‑function and Paigen diet - with the IKKε inhibitor amlexanox. Amlexanox modulated serum lipid levels and altered plaque composition but did not halt plaque progression. In the liver, treatment produced marked sex‑specific effects: male mice exhibited substantial improvement in steatosis, whereas female mice showed worsened lipid accumulation. These outcomes were reflected in pronounced sex‑dependent differences in serum and hepatic lipid and metabolite profiles, indicating regulation of fatty acid and bile-acid metabolism predominantly in males. Protein analyses in liver and adipose tissue further supported opposing metabolic and inflammatory responses between sexes after amlexanox treatment. Collectively, our findings indicate that therapeutic IKKε inhibition with amlexanox does not prevent progression of advanced atherosclerosis in this model but effectively ameliorates MASLD in male mice. In contrast, female mice experience aggravated hepatic lipid deposition. These results underscore the importance of incorporating sex‑specific analyses in metabolic and cardiovascular research and highlight the need to evaluate therapeutic strategies such as amlexanox in both sexes.