Drug Repurposing: Escitalopram attenuates acute lung injury by inhibiting the SIK2/ HDAC4/ NF-κB signaling cascade.

Acute lung injury (ALI) is a significant cause of morbidity and mortality worldwide. To search for a new treatment for acute lung injury, we investigated the effect of escitalopram on lipopolysaccharide (LPS)-induced ALI. Our results showed that escitalopram inhibited salt-inducible kinase 2 (SIK2) activity (IC = 6.36 ± 0.93 μM) and triggered histone deacetylase 4 (HDAC4) dephosphorylation. Following its dephosphorylation, HDAC4 translocated into the nucleus, promoted deacetylation and cytoplasmic shuttling of p65, thus inhibited LPS-induced pro-inflammatory cytokine production. Moreover, escitalopram markedly ameliorated the inflammatory responses, reduced neutrophils infiltration and attenuated LPS-induced pulmonary injury in mice. Taken together, we identified a previously unexplored role for escitalopram in SIK2/HDAC4/NF-κB pathway, therefore escitalopram may be considered as a new treatment for ALI.