Aqueous extract of Descuraniae Semen attenuates lipopolysaccharide‐induced inflammation by inhibiting ER stress and WNK4‐SPAK‐NKCC1 pathway

Sepsis causes systemic inflammatory responses and acute lung injury (ALI). Despite modern treatments, sepsis‐related ALI mortality remains high. Aqueous extract of Descuraniae Semen (AEDS) exerts anti‐endoplasmic reticulum (ER) stress, antioxidant and anti‐inflammatory effects. AEDS alleviates inflammation and oedema in ALI. Sodium‐potassium‐chloride co‐transporter isoform 1 (NKCC1) is essential for regulating alveolar fluid and is important in ALI. The NKCC1 activity is regulated by upstream with‐no‐lysine kinase‐4 (WNK4) and STE20/SPS1‐related proline/alanine‐rich kinase (SPAK). This study aimed to investigate the effects of AEDS on lipopolysaccharide (LPS)‐induced ALI model in A549 cells, considering the regulation of ER stress, WNK4‐SPAK‐NKCC1 cascades, inflammation and apoptosis. Cell viability was investigated by the CCK‐8 assay. The expressions of the proteins were assessed by immunoblotting analysis assays. The levels of pro‐inflammatory cytokines were determined by ELISA. The expression of cytoplasmic Ca 2+ in A549 cells was determined using Fluo‐4 AM. AEDS attenuates LPS‐induced inflammation, which is associated with increased pro‐inflammatory cytokine expression and activation of the WNK4‐SPAK‐NKCC1 pathway. AEDS inhibits the WNK4‐SPAK‐NKCC1 pathway by regulating of Bcl‐2, IP3R and intracellular Ca 2+ . WNK4 expression levels are significantly higher in the WNK4‐overexpressed transfected A549 cells and significantly decrease after AEDS treatment. AEDS attenuates LPS‐induced inflammation by inhibiting the WNK4‐SPAK‐NKCC1 cascade. Therefore, AEDS is regarded as a potential therapeutic agent for ALI.