Validating a Four-gene Set for H-ARS Severity Prediction in Peripheral Blood Samples of Irradiated Rhesus Macaques

Area of Science:

• Radiation Biology
• Genomics
• Toxicology

Background:

• Radiological and nuclear threats necessitate robust preparedness strategies.
• Hematological acute radiation syndrome (H-ARS) poses a significant health risk.
• Biomarkers are crucial for predicting H-ARS severity and guiding treatment.

Purpose of the Study:

• To validate previously identified gene expression biomarkers (DDB2, FDXR, POU2AF1, WNT3) for H-ARS severity prediction in Rhesus macaques.
• To assess the diagnostic utility of these genes in both male and female macaques.
• To examine gene expression changes in the extended post-irradiation phase.

Main Methods:

• Peripheral whole blood samples were collected from Rhesus macaques (Macaca mulatta) irradiated at doses of 5.8-7.2 Gy.
• Quantitative reverse transcription PCR (RT-PCR) was used to measure differential gene expression (DGE) of DDB2, FDXR, POU2AF1, and WNT3.
• Gene expression levels were analyzed at multiple time points: pre-irradiation and 1, 2, 3, 35, and 60 days post-irradiation.

Main Results:

• FDXR and DDB2 were significantly upregulated within three days post-irradiation, with DDB2 showing higher fold changes.
• POU2AF1 was consistently downregulated, supporting its role as a predictive biomarker.
• WNT3 expression showed variable patterns, with a trend towards downregulation in the early phase, and its diagnostic significance was not consistently reproduced.
• Gene expression levels in surviving animals returned to near pre-exposure values by day 60 post-irradiation.

Conclusions:

• The genes FDXR, DDB2, and POU2AF1 are validated as reliable predictors of H-ARS severity in the Rhesus macaque model.
• DDB2 demonstrated higher expression levels than FDXR, suggesting potentially greater sensitivity.
• The predictive value of WNT3 in Rhesus macaques was not confirmed, possibly due to model or methodological differences.