Caffeic Acid Cyclohexylamide Rescues Lethal Inflammation In Septic Mice Through Inhibition Of I Kappa B Kinase In Innate Immune Process

Targeting myeloid differentiation protein 2 (MD-2) or Toll-like receptor 4 (TLR4) with small molecule inhibitor rescues the systemic inflammatory response syndrome (SIRS) in sepsis due to infection with Gram-negative bacteria but not other microbes. Herein, we provided I kappa B kinase beta (IKK beta) in innate immune process as a molecular target of caffeic acid cyclohexylamide (CGA-JK3) in the treatment of polymicrobial TLR agonists- induced lethal inflammation. CGA-JK3 ameliorated E. coli lipopolysaccharide (LPS, MD-2/TLR4 agonist)-induced endotoxic shock, cecal ligation and puncture (CLP)-challenged septic shock or LPS plus D-galactosamine (GalN)-induced acute liver failure (ALF) in C57BL/6J mice. As a molecular basis, CGA-JK3 inhibited IKK beta-catalyzed kinase activity in a competitive mechanism with respect to ATP,displaced fluorescent ATP probe from the complex with IKK beta, and docked at the ATP-binding active site on the crystal structure of human IKK beta. Furthermore, CGA-JK3 inhibited IKK beta-catalyzed I kappa B phosphorylation, which is an axis leading to I kappa B degradation in the activating pathway of nuclear factor-kappa B (NF-kappa B), in macrophages stimulated with TLR (1/2, 2/6, 4, 5, 7, 9) agonists from Gram-positive/negative bacteria and viruses. CGA-JK3 consequently interrupted IKK beta-inducible NF-kappa B activation and NF kappa B-regulated expression of TNF-alpha, IL-1 alpha or HMGB-1 gene, thereby improving TLRs-associated redundant inflammatory responses in endotoxemia, polymicrobial sepsis and ALF.