Comparison of Signaling Profiles In the Low Dose Range Following Low and High LET Radiation

Publication date: Available online 22 February 2020Source: Life Sciences in Space ResearchAuthor(s): Deepa M. Sridharan, Lung-Chang Chien, Francis A. Cucinotta, Janice M. PluthABSTRACTDuring space travel astronauts will be exposed to a very low, mixed field of radiation containing different high LET particles of varying energies, over an extended period. Thus, defining how human cells respond to these complex low dose exposures is important in ascertaining risk. In the current study, we have chosen to investigate how low doses of three different ion's at various energies uniquely change the kinetics of three different phospho-proteins. A normal hTERT immortalized fibroblast cell line, 82-6, was exposed to a range of lower doses (0.05-0.5 Gy) of radiation of different qualities and energies (Si 1000, Si 300, Si 173, Si 93, Fe 1000, Fe 600, Fe 300, Ti 300, Ti326, Ti386 MeV/u), covering a wide span of LET's. Exposed samples were analyzed for the average intensity of signal as a fold over the geometric mean level of the sham controls. Three phospho-proteins known to localize to DNA DSBs following radiation (γH2AX, pATF2, pSMC1) were studied. The kinetics of their response was quantified by flow cytometery at 2 and 24 h post exposure. These studies reveal unique kinetic patterns based on the ion, energy, fluence and time following exposure. In addition, γH2AX phosphorylation patterns are uniquely different from phospho-proteins known to be primarily phosphorylated by ATM. This l...

Source: Life Sciences in Space Research - February 22, 2020 Category: Biology Source Type: research