Cardiovascular disease is the principal cause of mortality in developed societies. Studies have identified a correlation between radiotherapy for cancer and atherosclerosis in later life1. Endothelial cell dysfunction is a defining feature of atherosclerosis initiation. This study aims to investigate the effect of radiation on endothelial cell intracellular signalling networks, including the Nuclear Factor-kappaB (NFκB) and c-Jun N-terminal kinase (JNK) pathways. Human umbilical vein endothelial cells (HUVECs) were exposed to 10 Gy X-rays using an X-RAD 225 biological irradiator. Western blotting was used to detect NFκB and JNK pathway activation in whole cell lysates using anti-phospho-p65, anti-IκBα, anti-tp100/p52 and anti-phospho-JNK antibodies and in nuclear extracts using anti-NFκB-p65 antibodies. An in vitro kinase assay utilising 32P enabled detection of JNK-mediated phosphorylation of c-Jun. X-irradiation induced p65 phosphorylation (fold increase at 2hrs; 2.5±0.42, p<0.05, n=3) and IκBα degradation (fold at 8hrs; 0.29±0.05, n=3) in HUVECs, markers of canonical NFκB pathway activation. Surprisingly, nuclear p65 levels were not increased suggesting absence of p65 nuclear translocation. Interestingly, tp100/p52 levels were unaltered after irradiation implying that the non-canonical pathway is not activated. X-irradiation also triggered JNK phosphorylation (fold increase at 4hrs; 2.73±0.66, n=3) and JNK kinase activity, observed as increased phosphorylated c-Jun expression 4 hours after irradiation. Thus stress-associated signalling pathways (canonical NFκB and JNK pathways) are activated in irradiated endothelial cells. Further investigations will confirm the cellular events that link radiotherapy and cardiovascular disease.
Project supported by a British Heart Founation PhD studentship (no.Fs/13/25/30155).
- CARDIAC PROCEDURES AND THERAPY
Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.