title: Integrative proteomics and targeted transcriptomics analyses in cardiac endothelial cells unravel mechanisms of long-term radiation-induced vascular dysfunction.
abstract: Epidemiological data from radiotherapy patients show the damaging effect of ionizing radiation on heart and vasculature. The endothelium is the main target of radiation damage and contributes essentially to the development of cardiac injury. However, the molecular mechanisms behind the radiation-induced endothelial dysfunction are not fully understood. In the present study, 10-week-old C57Bl/6 mice received local X-ray heart doses of 8 or 16 Gy and were sacrificed after 16 weeks; the controls were sham-irradiated. The cardiac microvascular endothelial cells were isolated from the heart tissue using streptavidin-CD31-coated microbeads. The cells were lysed and proteins were labeled with duplex isotope-coded protein label methodology for quantification. All samples were analyzed by LC-ESI-MS/MS and Proteome Discoverer software. The proteomics data were further studied by bioinformatics tools and validated by targeted transcriptomics, immunoblotting, immunohistochemistry, and serum profiling. Radiation-induced endothelial dysfunction was characterized by impaired energy metabolism and perturbation of the insulin/IGF-PI3K-Akt signaling pathway. The data also strongly suggested premature endothelial senescence, increased oxidative stress, decreased NO availability, and enhanced inflammation as main causes of radiation-induced long-term vascular dysfunction. Detailed data on molecular mechanisms of radiation-induced vascular injury as compiled here are essential in developing radiotherapy strategies that minimize cardiovascular complications.
authors.affiliation: Helmholtz Zentrum München - German Research Centre for Environmental Health, Institute of Radiation Biology , Ingolstaedter Landstrasse 1, D-85764 Neuherberg, Germany.
authors.forename: Omid
authors.initials: O
authors.lastname: Azimzadeh
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Sievert
authors.forename: Hakan
authors.initials: H
authors.lastname: Sarioglu
authors.forename: Juliane
authors.initials: J
authors.lastname: Merl-Pham
authors.forename: Ramesh
authors.initials: R
authors.lastname: Yentrapalli
authors.forename: Mayur V
authors.initials: MV
authors.lastname: Bakshi
authors.forename: Dirk
authors.initials: D
authors.lastname: Janik
authors.forename: Marius
authors.initials: M
authors.lastname: Ueffing
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Atkinson
authors.forename: Gabriele
authors.initials: G
authors.lastname: Multhoff
authors.forename: Soile
authors.initials: S
authors.lastname: Tapio
mesh_terms: D000818:Animals; D001808:Blood Vessels / Q000166:cytology / Q000503:physiopathology / Q000528:radiation effects*; D002853:Chromatography, Liquid; D020869:Gene Expression Profiling; D051379:Mice; D008810:Mice, Inbred C57BL; D040901:Proteomics; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry; D059467:Transcriptome
keywords: ICPL; PI3K; PPAR alpha; cardiovascular disease; endothelial cell; endothelial cell dysfunction; heart; insulin; ionizing radiation; proteomics