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.

Quantitative and integrated proteome and microRNA analysis of endothelial replicative senescence

“…In the present study, proteins with ratio of heavy/light or medium/light greater than 1.3 fold or less than − 1.3 fold were considered to be significantly deregulated during senescence [22,23]. The biological significance of this fold change cut off is in good agreement with the previously published data [24,39].…”

Using proteomics to explore the effects of radiation on the heart - impacts for medicine

“…Endothelial cells proliferate rapidly in vitro and thus may not reflect the response of slowly proliferating endothelial cells of adult organs on ionizing irradiation. Proteomics analysis of cardiac endothelial cells isolated directly from mice that were locally irradiated to heart showed a significant inhibition of PI3K/Akt/eNOS pathway [8]. This study, using the isotope-coded protein label method, strongly suggested decreased NO availability and enhanced inflammation as the main causes of radiation-induced long-term cardiovascular dysfunction.…”

5‐fluorouracil causes endothelial cell senescence: potential protective role of glucagon‐like peptide 1

“…This information adds to the knowledge about the effects of 5FU on the cardiovascular system. More generally, it highlights that anticancer treatment-induced senescence of endothelial cells, which so far has mainly been described and discussed for doxorubicin (Spallarossa et al, 2010;Hodjat et al, 2013;De Falco et al, 2016) and ionizing radiation (Azimzadeh et al, 2015;Park et al, 2016), may also be relevant for other oncological therapies. In the heart, 5FU-initiated senescence might at least in part contribute to coronary spasm and/or microvascular disease and might promote the formation and progression of coronary atherosclerotic lesions, as endothelial senescence has been implicated in atherogenesis (Yin and Pickering, 2016).…”