Callerya atropurpurea suppresses inflammation in vitro and ameliorates gastric injury as well as septic shock in vivo via TLR4/MyD88-dependent cascade

Background: Callerya atropurpurea is a traditional plant in a tropical zone discovered to have anti-inflammatory functions. Purpose: we want to investigate the mechanism related to anti-inflammation of C. atropurpurea ethanol extract (Ca-EE) both in vitro and in vivo. Study design: Murine macrophage cells and mouse models for gastritis and septic shock were conducted to evaluate the abilities of Ca-EE in anti-inflammation. Methods: Ca-EE was tested by HPLC and LC-MS/MS. NO outcome was checked by Griess reagent test. Cell viabilities were evaluated using MTT assay. Inflammatory cytokines were determined via RT-PCR and ELISA. The mechanism of Ca-EE in anti-inflammation was investigated by luciferase reporter gene assay and immunoblot in transcription level and protein level respectively. Gastric injury and septic shock administrated with Ca-EE were studied by H&E, PCR, and immunoblot. Results: Ca-EE significantly decreased LPS-induced NO production, but hardly stimulated the expression of NO itself. It not only showed no cytotoxicity, but also protected cells from LPS damage. Moreover, Ca-EE decreased TLR4 expression, altered MyD88 recruitment and TRAF6, and suppressed the phospho-Src/PI3K/AKT. Ca-EE inhibited downstream signaling P38, JNK and NF-κB. Finally, Ca-EE alleviated HCl/EtOH-induced gastritis and LPS/poly (I:C)-induced septic shock through the previously mentioned signaling cascades. Conclusion: Ca-EE exhibited an integrated and promising mechanism against TLR4-related inflammation, which shows potential for treating gastritis, septic shock, and other inflammatory diseases.