The Pro-inflammatory Effects Of Cigarette Smoke Extract On Monocytes

Objective:To investigate whether cigarette smoke extract(CSE)can induce the secretion of IL-1? via exosomes by monocytes,and to explore the potential protective mechanism of melatonin during this process.Methods:THP-1 cells are divided into 5 groups:LPS group,CSE group,CSE+MT group,ATP group and blank control group.After 20 hours' stimulation of LPS,CSE,CSE+MT,complete medium and complete medium respectively,the culture medium was changed to FBS-free medium with 5mM ATP(beside blank control group,whose medium wasn't added ATP).After 30 minutes incubation,the culture medium is used to acquire exosomes using ultracentrifugation method.The IL-1? concentration is detected in cell lysis and exosomes sample.And some upstream signal molecules of IL-1? are detected.Results:The CSE solution was successfully prepared using the cigarette smoke extracting equipment,and 5%was determined for the working concentration of CSE.Exosomes were successfully acquired in LPS group,CSE group and CSE+MT group,while not in the other two.The existence of exosomes in these samples were confirmed using transmission electron microscope and Western blot.Active-IL-1? was detected in the exosomes sample of CSE and CSE+MT groups,but not in ATP group and blank control group.And the concentration of active-IL-1? in CSE+MT group was lower than that in CSE group.The concentrations of NF-?B,NLRP3,caspase-1 in CSE+MT group were lower than those in CSE group.The concentrations of NF-?B,NLRP3,caspase-1 in LPS+MT group were lower than those in LPS group.Conclusions:CSE can cause THP-1 cells to give out exosomes,which contain active-IL-1?.NLRP3 inflammasomes related pathway may be involved in the protective effects of melatonin in CSE-caused IL-1? secretion.