Effects of let-7e on the LPS-induced expression of TNF-α and the possible mechanism
10.3760/cma.j.issn.0254-5101.2015.12.005
- VernacularTitle:MicroRNA let-7e对LPS诱导的TNF-α表达的影响及机制的初步研究
- Author:
Qianqian ZHANG
;
Yingke ZHANG
;
Lian GUI
;
Junqi HUANG
- Publication Type:Journal Article
- Keywords:
Primary monocytes;
let-7e;
TNF-α;
LPS
- From:
Chinese Journal of Microbiology and Immunology
2015;35(12):884-889
- CountryChina
- Language:Chinese
-
Abstract:
Objective To study the effects of a miRNA family member,let-7e,on the LPS-induced expression of TNF-α in primary monocytes and the possible mechanism.Methods Peripheral blood mononuclear cells (PBMCs) were isolated form human blood sample by using density gradient centrifugation for further isolation of primary monocytes.Flow cytometry analysis was used to measure the purity of isolated primary monocytes.The efficiencies of transfection were evaluated by qRT-PCR and immunofluorescence assay after transfecting the primary monocytes with let-7e mimic or miRNA mimic negative control (NC) for 24 h,36 h and 48 h.To screen out the optimal stimulation time,ELISA was performed to detect the concentrations of TNF-α in the supernatants of cell culture after stimulating the primary monocytes with 1 mg/L of LPS for 0 h,1 h,3 h,6 h and 12 h,respectively.ELISA and qRT-PCR were used to measure the expression of TNF-α in the transfected cells with the interference of LPS.Western blot assay was used to detect the level of enhancer of zeste homolog 2 (EZH2) in let-7e mimic-transfected primary monocytes and the levels of NF-κB p65,ADP-ribosylation factor GTPase-activating protein 1 (ARFGAP1) and Arfaptin2 in the siEZH2-transfected monocytes.Results More than 70％ of the isolated cells were CD14+ cells.The miRNA mimics could transfect the primary monocytes effectively and the transfection rate was about 70％.High levels of let7e were detected in let-7e mimic-transfected primary monocytes 24 hours after the transfection.High levels of TNF-α were observed in the primary monocytes after stimulated with LPS for 12 h,which was considered as the optimal LPS stimulation time.Results of the ELISA indicated that let-7e mimic significantly inhibited the LPS-induced expression of TNF-α in primary monocytes at both mRNA and protein levels.Western blot assay showed that the levels of EZH2 in the let-7e mimic transfected primary monocytes were significantly lower than that in mimic NC transfected primary monocytes.Silenced expression of EZH2 significantly inhibited the expression of NF-κB p65 in nucleus as well as the expression of ARFGAP1 and Arfaptin2.Conclusion let-7e mimic significantly inhibited the LPS-induced expression of TNF-α in primary monocytes.It is possible that Let-7e regulates the expression of NF-κB p65,ARFGAP1 and Arfaptin2 by targeting EZH2 directly to inhibit the expression of TNF-α.
