title: Alu RNA accumulation in hyperglycemia augments oxidative stress and impairs eNOS and SOD2 expression in endothelial cells.
abstract: Endothelial dysfunction resulting from oxidative stress and inflammation plays a dominant role in hyperglycemia-induced vasculopathy. While double-stranded RNA (dsRNA) accumulates in redox and inflammatory conditions, its precise role in hyperglycemia-associated endothelial dysfunction remains unclear. This study aimed to investigate whether and how endogenous dsRNA contributes to endothelial dysfunction via oxidative stress. We used a dsRNA-specific antibody J2 to detect and immunoprecipitate cellular dsRNA. Acquired dsRNA was recognized by cDNA library construction and DNA sequencing. Quantitative PCR, ELISA and immunoassays were performed to identify changes induced by acquired dsRNA in primary human umbilical vein endothelial cells (HUVEC). Our data showed that endogenous dsRNA homologous to Alu Sc subfamily accumulated in hyperglycemic HUVEC. Comparing Alu-transfected HUVEC with high-glucose treated HUVEC, we found that Alu RNA elicited the production of reactive oxygen species (ROS) and up-regulated interleukin-1β (IL-1β) expression and secretion in a similar manner as high-glucose treatment. Moreover, Alu RNA impeded the expression of endothelial nitric oxide synthase (eNOS) and superoxide dismutase 2 (SOD2), increased ROS production and activated nuclear factor NFκB by chemically scavenging ROS and inactivation of NFκB. The repressed expression of eNOS and SOD2 resulted from Alu RNA-mediated negative regulatory mechanisms. Our study uncovered endogenous Alu RNA accumulation in hyperglycemic endothelial cells that provoked endothelial oxidative stress and dysfunction by suppressing SOD2 and eNOS expression at both transcription and translation levels via NFκB signaling pathway. These findings suggest a novel regulatory mechanism that involves endogenous dsRNA in endothelial oxidative stress and dysfunction.
authors.affiliation: State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Wei-Hua
authors.initials: WH
authors.lastname: Wang
authors.affiliation: Departments of Urology and Surgery, VA Boston Healthcare System, Boston University School of Medicine, Boston 510660, MA, USA.
authors.forename: Kazem M
authors.initials: KM
authors.lastname: Azadzoi
authors.affiliation: State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Dai
authors.affiliation: State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Jian-Bin
authors.initials: JB
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Wen-Tao
authors.initials: WT
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Shu
authors.affiliation: State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China; Departments of Urology and Surgery, VA Boston Healthcare System, Boston University School of Medicine, Boston 510660, MA, USA. Electronic address: jyang@bu.edu.
authors.forename: Jing-Hua
authors.initials: JH
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China. Electronic address: yanzhen@fmmu.edu.cn.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Yan
mesh_terms: D020087:Alu Elements; D001483:Base Sequence; D002478:Cells, Cultured; D004794:Enzyme Repression; D005947:Glucose / Q000502:physiology; D061307:Human Umbilical Vein Endothelial Cells / Q000201:enzymology*; D006801:Humans; D006943:Hyperglycemia; D053583:Interleukin-1beta / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D018384:Oxidative Stress; D012330:RNA, Double-Stranded / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D000099156:Superoxide Dismutase 2
chemical_list: D005947:Glucose; D053583:Interleukin-1beta; D016328:NF-kappa B; D052250:Nitric Oxide Synthase Type III; D012330:RNA, Double-Stranded; D013482:Superoxide Dismutase; D014409:Tumor Necrosis Factor-alpha; D000099156:Superoxide Dismutase 2; C439524:TNF protein, human; C496314:NOS3 protein, human
keywords: Alu RNA; Diabetes; Double-stranded RNA; Endothelial cells; Oxidative stress