Targeting TLR4/3 using chlorogenic acid ameliorates LPS plus POLY I:C-induced acute respiratory distress syndrome via alleviating oxidative stress-mediated NLRP3/NF-κB axis

Acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) is a life-threatening condition caused due to significant pulmonary and systemic inflammation. Chlorogenic acid (CGA) has been shown to possess potent antioxidant, anti-inflammatory, and immunopro-tective properties. However, the protective effect of CGA on viral and bacterial-induced ALI/ARDS is not yet explored. Hence, the current study is aimed to evaluate the preclin-ical efficacy of CGA in lipopolysaccharide (LPS) and polyinosinic:polycytidylic acid (POLY I:C)-induced ALI/ARDS models in vitro and in vivo. Human airway epithelial (BEAS-2B) cells exposed to LPS+POLY I:C significantly elevated oxidative stress and inflammatory signal-ing. Co-treatment with CGA (10 and 50 mu M) prevented inflammation and oxidative stress mediated by TLR4/TLR3 and NLRP3 inflammasome axis. BALB/c mice, when chronically challenged with LPS+POLY I:C showed a significant influx of immune cells, up-regulation of pro-inflammatory cytokines, namely: IL-6, IL-1 beta, and TNF-alpha, and treatment with intranasal CGA (1 and 5 mg/kg) normalized the elevated levels of immune cell infiltration as well as pro-inflammatory cytokines. D-Dimer, the serum marker for intravascular coagulation, was significantly increased in LPS+ POLY I:C challenged animals which was reduced with CGA treatment. Further, CGA treatment also has a beneficial effect on the lung and heart, as shown by improving lung physiological and cardiac functional parameters accompanied by the elevated antioxidant response and simultaneous reduction in tissue damage caused by LPS+POLY I:C co-infection. In summary, these comprehensive, in vitro and in vivo stud-ies suggest that CGA may be a viable therapeutic option for bacterial and viral-induced ALI-ARDS-like pathology.

Automated summary

Chlorogenic acid (CGA) has potent antioxidant, anti-inflammatory, and immunoprotective properties, and can prevent viral and bacterial-induced acute lung injury/acute respiratory distress syndrome (ALI/ARDS). In vitro and in vivo studies have shown that CGA can prevent inflammation, oxidative stress, and tissue damage, and improve lung and heart function.