ObjectiveTo prepare curcumin loaded monomethoxyl poly(ethylene glycol)-poly(lactic-co-glycolicacid) (mPEG-PLGA) nanopaticles (CUR-NPs), investigate the effect of curcumin (CUR) and CUR-NPs on reversing corticosteroid resistance induced by cigarette smoke extract (CSE), and compare biological function between CUR and CUR-NPs in macrophages RAW264.7. MethodsmPEG-PLGA nanoparticles loaded with CUR were prepared via emulsion solvent evaporation.In lipopolysaccharide (LPS) stimulated macrophages RAW264.7, budesonide (BUD) was used to treat macrophages RAW264.7.In LPS and CSE stimulated macrophages RAW264.7, BUD (10-10-10-5 mol/L), CUR(10-10-10-5 mol/L), CUR(10-7 mol/L)+BUD(10-9-10-5 mol/L), CUR(10-9-10-5 mol/L)+BUD(10-7 mol/L), and CUR-NPs(10-9-10-5 mol/L)+BUD(10-7 mol/L) were respectively used to treat macrophages RAW264.7 activated.The level of IL-8 in cell culture supernatant was measured by ELISA.In CSE stimulated macrophages RAW264.7, CUR(10-7 and 10-6 mol/L) and CUR-NPs(10-7 and 10-6 mol/L) were used to treat macrophages RAW264.7.The mRNA level of HDAC2 was measured by real-time PCR, the protein level of HDAC2 was measured by Western blot.Cellular uptake of CUR and CUR-NPs in macrophages RAW264.7 was determined by cellular fluorescence intensity observed and detected by laser confocal microscopy imaging. ResultsThe morphology of CUR-NPs was spherical and the mean particle size was (356.4±146.6)nm.Compared with LPS stimulation, co-stimulation of LPS and CSE led to a significant decrease in the maximum inhibitory rate of BUD on IL-8 (P < 0.05) and a significant increase in the 50% inhibitory concentration (IC50) of BUD on IL-8 (P < 0.05).When using LPS+CSE to stimulate, compared with BUD (10-10-10-5 mol/L) group, the maximum inhibitory rate of BUD in CUR (10-7 mol/L)+BUD (10-9-10-5 mol/L) group on IL-8 was significantly higher (P < 0.05) and the IC50 of BUD decreased significantly (P < 0.05).When using LPS+CSE to stimulate, CUR and CUR-NPs in 10-9, 10-8 and 10-7 mol/L concentration, the inhibitory rate of CUR-NPs+BUD (10-7 mol/L) on IL-8 was significantly higher than that of CUR+BUD (10-7 mol/L) (P < 0.05). CSE stimulation induced a significant decrease in the mRNA and protein expression of HDAC2. Compared with CSE group, the mRNA and protein levels of HDAC2 of CUR(10-7 and 10-6 mol/L) group and CUR-NPs(10-7 and 10-6 mol/L) group were significantly higher (P < 0.05).In 10-7 mol/L concentration, the mRNA and protein levels of HDAC2 in CUR-NPs group were significantly higher than those in CUR group.In 10-7 mol/L concentration, cellular uptake of CUR in CUR-NPs was significantly higher than the native CUR. ConclusionsCUR and CUR-NPs can reverse the corticosteroid resistance induced by CSE.CUR-NPs can improve the cellular uptake of CUR.In the case of low concentration, CUR-NPs have more biological activity than CUR.
ObjectiveTo investigate the role of PI3K/AKT/mTOR signaling pathway in skeletal muscle atrophy in rats with chronic obstructive pulmonary diseases(COPD). MethodsPassive cigarette smoking was used to establish COPD model.The protein expression of PI3K, total mTOR, phosphorylated-mTOR, total GSK-3β, phosphorylated-GSK-3β, total 4E-BP1, phosphorylated-4E-BP1, total p70S6K1 and phosphorylated-p70S6K1 in extensor digitorum longus of rats were measured by Western blot. ResultsThe protein expression of PI3K was not significantly different between two groups(P > 0.05).Compared with the control group, the protein expression of total mTOR, phosphorylated-mTOR, total GSK-3β, and phosphorylated-GSK-3βincreased significantly in the COPD group(P < 0.05).The protein expression of total 4E-BP1 and total p70S6K1 were not significantly different between two groups(P > 0.05).While the protein expression of phosphorylated-4E-BP1 and phosphorylated-p70S6K1 significantly increased in the COPD group(P < 0.05). ConclusionThe protein expressions of PI3K/AKT/mTOR signaling pathway in extensor digitorum longus increased significantly in COPD rats, suggesting that the activity of PI3K/AKT/mTOR signaling pathway increased, which may be one of the compensatory mechanism of skeletal muscle atrophy in COPD.