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Controlof immune responses through the immunometabolism interference is interesting for sepsis treatment. Then, expression of immunometabolism-associated genes and BAM15, a mitochondrial uncoupling agent, was explored in a proinflammatory model using lipopolysaccharide (LPS) injection. Accordingly, the decreased expression of mitochondrial uncoupling proteins was demonstrated by transcriptomic analysis on metabolism-associated genes in macrophages (RAW246.7) and by polymerase chain reaction in LPS-stimulated RAW246.7 and hepatocytes (Hepa 1–6). Pretreatment with BAM15 at 24 h prior to LPS in macrophages attenuated supernatant inflammatory cytokines (IL-6, TNF-α, and IL-10), downregulated genes of proinflammatory M1 polarization (iNOS and IL-1β), upregulated anti-inflammatory M2 polarization (Arg1 and FIZZ), and decreased cell energy status (extracellular flux analysis and ATP production). Likewise, BAM15 decreased expression of proinflammatory genes (IL-6, TNF-α, IL-10, and iNOS) and reduced cell energy in hepatocytes. In LPS-administered mice, BAM15 attenuated serum cytokines, organ injury (liver enzymes and serum creatinine), and tissue cytokines (livers and kidneys), in part, through the enhanced phosphorylated αAMPK, a sensor of ATP depletion with anti-inflammatory property, in the liver, and reduced inflammatory monocytes/macrophages (Ly6C +ve, CD11b +ve) in the liver as detected by Western blot and flow cytometry, respectively. In conclusion, a proof of concept for inflammation attenuation of BAM15 through metabolic interference-induced anti-inflammation on macrophages and hepatocytes was demonstrated as a new strategy of anti-inflammation in sepsis.

The impact of spleen tyrosine kinase (Syk) signaling might be prominent in lupus because (i) Syk is a shared downstream signaling molecule among circulating immune complex, LPS, and (1→3)-β-D-glucan (BG), and (ii) all of these factors are detectable in the serum of Fc gamma receptor IIb-deficient (FcgRIIb−/−) mice with sepsis. As a proof of concept study, we activated macrophages with BG combined with LPS (BG + LPS). We found that BG + LPS predominantly upregulated Syk expression and proinflammatory cytokines in FcgRIIb−/− macrophages compared with wild-type (WT) macrophages. Syk inhibition downregulated several inflammatory pathways in FcgRIIb−/− macrophages activated with BG + LPS, as determined by RNA sequencing analysis, suggesting the potential anti-inflammatory impact of Syk inhibitors in lupus. Indeed, administration of a Syk inhibitor prior to cecal ligation and puncture (CLP) sepsis in FcgRIIb−/− mice reduced baseline lupus-induced proinflammatory cytokines and attenuated sepsis severity as evaluated by mortality, organ injury, serum LPS, and post-sepsis serum cytokines. In conclusion, it was easier to induce Syk expression in FcgRIIb−/− macrophages than in WT macrophages. This might be because of the loss of inhibitory signaling, which might be responsible for prominent Syk abundance in the spleens of 40-week-old FcgRIIb−/− mice and the potent effect of Syk inhibitor in lupus mice compared with WT.