Discovery of Chrysoeriol,a PI3K-AKT-mTOR Pathway Inhibitor with Potent Antitumor Activity against Human Multiple Myeloma Cells in vitro

This study was designed to determine the impact of chrysoeriol on proliferation and cell cycle progression in the human multiple myeloma cell lines RPMI 8226 and KM3,and its related molecular mechanisms.Chryseoriol was identified by using the phosphorylated AKT-specific cytoblot high throughput assay.CCK-8 assay was employed to examine the growth inhibition rate and IC 50 (48 h) in peripheral blood mononuclear cells (PBMNCs),RPMI 8226 and KM3 cells treated with chrysoeriol at various concentrations.Cells were labeled with 5-6-carboxyfluorescein diacetate succinimidyl ester (CFSE),and the proliferation dynamics was detected by flow cytometry and analyzed with ModFit software.The cell cycles of RPMI 8226 and KM3 cells were measured by flow cytometry when the IC 50 concentration of chrysoeriol was adopted.The alterations in cell-cycle related proteins (Cyclin B1,Cyclin D1,p21) and proteins in PI3K-AKT-mTOR pathway were determined by Western blot analysis.The results showed the proliferation of multiple myeloma cells was significantly inhibited by chrysoeriol,resulting in cell cycle arrest in G 2 /M phase.Chrysoeriol could significantly reduce the expression of p-AKT (s473) and p-4eBP1 (t37/46) protein,meanwhile enhanced Cyclin B1 and p21 protein expression.Similar effects were not observed in PBMNCs from normal donors.It was concluded that chrysoeriol was a selective PI3K-AKT-mTOR pathway inhibitor.It restrained the proliferation of human multiple myeloma cells,but didn’t affect proliferation of PBMNCs from normal donors.It might exhibit the cell cycle regulatory effect via the inhibition of PI3K-AKT-mTOR signal pathway.

African swine fever virus MGF505-3R inhibits cGAS-STING-mediated IFN-βpathway activation by degrading TBK1

African swine fever virus(ASFV)is an important pathogen causing acute infectious disease in domestic pigs and wild boars that seriously endangers the global swine industry.As ASFV is structurally complex and encodes a large number of functional proteins,no effective vaccine has been developed to date.Thus,dissecting the mechanisms of immune escape induced by ASFV proteins is crucial.A previous study showed that the ASFV-encoded protein is an important factor in host immunity.In this study,we identified a negative regulator,MGF505-3R,that significantly downregulated cGAS/STING-and poly(dG:dC)-mediated IFN-βand interferon stimulation response element(ISRE)reporter activity and suppressed IFNB1 and IFIT2 mRNA levels.In addition,TBK1,IRF3 and IκBαphosphorylation levels were also inhibited.Mechanistically,MGF505-3R interacted with cGAS/TBK1/IRF3 and targeted TBK1 for degradation,thereby disrupting the cGAS-STING-mediated IFN-βsignaling pathway,which appears to be highly correlated with autophagy.Knockdown MGF505-3R expression enhanced IFN-βand IL-1βproduction.Taken together,our study revealed a negative regulatory mechanism involving the MGF505-3R-cGAS-STING axis and provided insights into an evasion strategy employed by ASFV that involves autophagy and innate signaling pathways.

Mechanism of Sanshi decoction in the treatment of gouty arthritis by NLRP3 inflammasome

Objective:To observe the effect of Sanshi decoction on P2X7R/PKR pathway-mediated activation of macrophage NLRP3 inflammasome to elucidate the molecular mechanism of Sanshi decoction in the treatment of gouty arthritis.Methods:THP-1 macrophages were divided into control group,model group,low dose group,medium dose group,high dose group of Sanshi decoction and inhibitor group.The remaining groups were induced with monosodium urate crystals to establish a gouty arthritis cell model except the control group.Flow cytometry was used to detect macrophage ROS levels in each group,ELISA to detect MDA levels and SOD and GSH-PX activities in each group,and Western blot to detect P2X7R/PKR pathway and NLRP3 inflammasome-associated protein expression.We also used CCK-8 and flow cytometry to measure MH7A activity and apoptotic levels.Results:Compared with the control group,the ROS level,the content of MDA,the activities of SOD and GSH-PX were significantly increased,and the expression levels of NLRP3,full-length IL-1β,pro-IL-1β,full-length IL-18,pro-IL-18,full-length caspase-1,GSDMD-NT,P2X7R and p-PKR protein expression levels were significantly upregulated,and GSDMD-FL protein expression was significantly downregulated in the model group,and that the differences between them were statistically significant(P<0.05 and P<0.01).Compared with the model group,Sanshi decoction could reduce macrophage ROS levels,MDA content,SOD and GSHPX activities,and downregulate macrophage NLRP3,mature IL-1β,pro IL-1β,mature IL-18,pro IL-18,mature caspase-1,GSDMD-NT,P2X7R and p-PKR protein expression,and upregulate GSDMD-FL protein expression,with statistically significant differences(P<0.05 and P<0.01).In addition,MH7A activity was downregulated,and apoptosis level was upregulated in the model group in comparison with the control group,and differences were all significantly different(P<0.05).As compared to the model group,Sanshi decoction could significantly increase the activity of MH7A and inhibit the level of apoptosis,and that the differences between them were statistically significant(P<0.05 and P<0.01).Conclusion:Sanshi decoction can achieve the therapeutic effect of gouty arthritis by inhibiting P2X7R/PKR pathway activation,thus reducing the activation level of NLRP3.

Decrease in myostatin by ladder-climbing training is associated with insulin resistance in diet-induced obese rats

Background Suppression of myostatin （MSTN） has been associated with skeletal muscle atrophy and insulin resistance （IR）.However,few studies link MSTN suppression by ladder-climbing training （LCT） and IR.Therefore,we intended to identify the correlation with IR between LCT and to analyze the signaling pathways through which MSTN suppression by LCT regulates IR.Methods The rats were randomly assigned to two types of diet：normal pellet diet （NPD,n=8） and high-fat diet （HFD,n=16）.After 8 weeks,the HFD rats were randomly re-assigned to two groups （n=8 for each group）：HFD sedentary （HFD-S） and high-fat diet ladder-climbing training （HFD-LCT）.HFD-LCT rats were assigned to LCT for 8 weeks.Western blotting,immunohistochemistry and enzyme assays were used to measure expression levels and activities of MSTN,GLUT4,PI3K,Akt and Akt-activated targets （mTOR,FoxO1 and GSK-3β）.Results The LCT significantly improved IR and whole-body insulin sensitivity in HDF-fed rats.MSTN protein levels decreased in matching serum （42％,P=0.007） and muscle samples （25％,P=0.035） and its receptor mRNA expression also decreased （16％,P=0.041） from obese rats after LCT.But the mRNA expression of insulin receptor had no obvious changes in LCT group compared with NPD and HFD-S groups （P=0.074）.The ladder-climbing training significantly enhanced PI3K activity （1.7-fold,P=0.024） and Akt phosphorylation （83.3％,P=0.022） in HFD-fed rats,significantly increased GLUT4 protein expression （84.5％,P=-0.036）,enhanced phosphorylation of mTOR （4.8-fold,P ＜0.001） and inhibited phosphorylation of FoxO1 （57.7％,P=0.020）,but did not affect the phosphorylation of GSK-3β.Conclusions The LCT significantly reduced IR in diet-induced obese rats.MSTN may play an important role in regulating IR and fat accumulation by LCT via PI3K/Akt/mTOR and PI3K/Akt/FoxO1 signaling pathway in HFD-fed rats.