title: Chloroquine attenuates LPS-mediated macrophage activation through miR-669n-regulated SENP6 protein translation.
abstract: Chloroquine (CQ) has been shown to inhibit Toll-like receptor 4 (TLR4)-mediated monocyte and macrophage activation induced by lipopolysaccharide (LPS). However, the underlying mechanisms have not been completely elucidated. Recently, SUMO-specific protease 6 (SENP6) has been reported to suppress LPS-induced activation of macrophages through deSUMOlation of NF-κB essential modifier (NEMO). Here, we studied whether this molecular pathway may also be involved in CQ/LPS model. We found that CQ dose-dependently increased SENP6 protein, but not mRNA, in mouse macrophages, RAW264.7 cells. Overexpression of SENP6 in RAW264.7 cells significantly decreased the LPS-induced release of pro-inflammatory proteins, TNF-α, IL-6 and IFN-γ, while depletion of SENP6 in RAW264.7 cells significantly increased these proteins. Moreover, in LPS-treated RAW264.7 cells, CQ dose-dependently decreased the levels of microRNA-669n (miR-669n), which bound to 3'-UTR of SENP6 mRNA to inhibit its translation. Overexpression of miR-669n decreased SENP6, resulting in increased production of TNF-α, IL-6 and IFN-γ in RAW264.7 cells, while depletion of miR-669n increased SENP6, resulting in decreased production of TNF-α, IL-6 and IFN-γ in RAW264.7 cells. In vivo, delivery of miR-669n plasmids augmented the effects of LPS, while delivery of antisense of miR-669n (as-miR-669n) plasmids abolished the effects of LPS. Taken together, our data demonstrate a previously unappreciated molecular control of LPS-induced macrophage activation by CQ, through miR-669n-regulated SENP6 protein translation.
authors.affiliation: Medical Research Center, Southwestern Hospital, The Third Military Medical University Chongqing 400038, China.
authors.forename: Yupeng
authors.initials: Y
authors.lastname: Long
authors.affiliation: Medical Research Center, Southwestern Hospital, The Third Military Medical University Chongqing 400038, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.affiliation: Medical Research Center, Southwestern Hospital, The Third Military Medical University Chongqing 400038, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Wang
authors.affiliation: Department of Pharmacology, College of Pharmacy, The Third Military Medical University Chongqing 400038, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Medical Research Center, Southwestern Hospital, The Third Military Medical University Chongqing 400038, China.
authors.forename: Jiang
authors.initials: J
authors.lastname: Zheng
keywords: Chloroquine (CQ); LPS; SENP6; bioinformatics analyses; miR-669n; miRNAs