Artesunate interacts with Vitamin D receptor to reverse mouse model of sepsis-induced immunosuppression via enhancing autophagy

Shenglan Shang; Jiaqi Wu; Xiaoli Li; Xin Liu; Pan Li; Chunli Zheng; Yonghua Wang; Songqing Liu; Jiang Zheng; Hong Zhou

Based on the concentration-effect relationship between LPS and cytokine production ( Figure . CC-BY-NC-ND 4.0 International license author/funder. It is made available under a The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.02.26.966143 doi: bioRxiv preprint 24 2a), 5 ng/mL LPS of four-hour incubation followed by 100 ng/mL LPS was determined to induce LPS tolerance phenotype (tolerance cells) (Figure 2b ). Compared with cells treated with only 100 ng/mL LPS treatment (LPS cells), tolerance cells pretreated with 5 ng/mL LPS and followed by 100 ng/mL LPS released much less TNF-α and IL-6 ( Figure 2c ). However, AS exhibited a dose-dependent enhancement of TNF-α and IL-6 release in tolerance cells ( Figure 2d) . The results showed the bacterial loads in LPS tolerance cells increased relative to LPS cells at 2 h after PA challenge. Significantly, AS decreased the bacteria load in tolerance cells ( Figure 2e ). Noteworthily, since the concentrations of LPS (2.5 -200 ng/mL) and AS(0.625 -40 μg/ml) used in the experiment had no effect on cell viability, the above effect was not related to the toxicity of LPS and AS on cell activity ( Figure S1a ) (Li et al., 2008) . Subsequent, the human monocyte cell line THP-1 and THP-1 derived macrophages were employed to confirm whether there is a similar effect in human cells. The identical results in the mRNA levels of TNF-α and IL-6 and bacterial clearance in THP-1 cells and THP-1 derived macrophages were obtained (Figure 2f, g) . These results were consistent with the findings in vivo, demonstrating that AS might reverse sepsis-induced immunosuppression through enhancing pro-inflammatory cytokines release and bacterial clearance by macrophages.