AQP9 and serum lipopolysaccharide activity: In this study, we use both a murine model of LPS-induced endotoxemia in the presence or absence of AQP9 (Aqp9−/− knockout mice) and a cell model that was treated with LPS, with or without blocking AQP9 to evaluate whether this AQP is involved in the systemic inflammation that is caused by endotoxins and to study the signaling pathways involved.