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Identification of gene-based responses in human blood cells exposed to alpha particle radiation.

Chauhan V, Howland M, Wilkins R - BMC Med Genomics (2014)

Bottom Line: Microarray technology was employed to identify transcripts that were differentially expressed relative to unirradiated cells 24 hours post-exposure.Twenty-nine genes were common to all doses with expression levels ranging from 2-10 fold relative to control treatment group.This 29 gene panel was responsive in the α-particle exposed WBCs and was shown to exhibit differential fold-changes compared to X-irradiated cells, though no α-particle specific transcripts were identified.

View Article: PubMed Central - HTML - PubMed

Affiliation: Consumer and Clinical Radiation Protection Bureau, Healthy Environment and Consumer Safety Branch, Health Canada, 775 Brookfield Road, PL 6303B, Ottawa, ON K1A 1C1, Canada. Vinita.chauhan@hc-sc.gc.ca.

ABSTRACT

Background: The threat of a terrorist-precipitated nuclear event places humans at danger for radiological exposures. Isotopes which emit alpha (α)-particle radiation pose the highest risk. Currently, gene expression signatures are being developed for radiation biodosimetry and triage with respect to ionizing photon radiation. This study was designed to determine if similar gene expression profiles are obtained after exposures involving α-particles.

Methods: Peripheral blood mononuclear cells (PBMCs) were used to identify sensitive and robust gene-based biomarkers of α-particle radiation exposure. Cells were isolated from healthy individuals and were irradiated at doses ranging from 0-1.5 Gy. Microarray technology was employed to identify transcripts that were differentially expressed relative to unirradiated cells 24 hours post-exposure. Statistical analysis identified modulated genes at each of the individual doses.

Results: Twenty-nine genes were common to all doses with expression levels ranging from 2-10 fold relative to control treatment group. This subset of genes was further assessed in independent complete white blood cell (WBC) populations exposed to either α-particles or X-rays using quantitative real-time PCR. This 29 gene panel was responsive in the α-particle exposed WBCs and was shown to exhibit differential fold-changes compared to X-irradiated cells, though no α-particle specific transcripts were identified.

Conclusion: Current gene panels for photon radiation may also be applicable for use in α-particle radiation biodosimetry.

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Related in: MedlinePlus

Median based hierarchical clustering dataset to determine common groupings of samples and genes. Dataset is obtained from qPCR results in isolated white blood cells exposed to α-particle and X-ray radiation.
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Figure 6: Median based hierarchical clustering dataset to determine common groupings of samples and genes. Dataset is obtained from qPCR results in isolated white blood cells exposed to α-particle and X-ray radiation.

Mentions: WBCs were isolated from 12 healthy individuals and exposed to α-particles and X-rays. Total white blood cell counts were typically in the range of 5-10 × 106 cells/mL. The viability of the cells was assessed using the Trypan Blue viability assay pre- and post-irradiation. The cells remained viable (above 98%) and no significant changes in blood cell counts or populations subsets were observed post-irradiation relative to unirradiated cells (Table 4). Twenty-four hours after irradiation, RNA was extracted and reverse transcribed to cDNA. A comparison of the differential gene responses obtained from the qPCR of WBCs and microarray analysis of PBMCs showed similar fold change and statistical significance for the majority of the 68 transcripts that were assessed (Table 5). These responding genes were compared to those obtained for X-ray exposed cells. Box-plots of the responding genes from the WBC qPCR dataset allowed for a visual comparison of the two radiation types and the range in inter-individual variability between transcripts (Figure 5). Overall, all genes responsive in α-particle treated cells were also observed to be expressed in X-irradiated cells. The data displayed minimal variability between control treatment groups under varied radiation exposure conditions. Furthermore, the majority of genes displayed dose-response trends for both α-particle and X-ray radiation. Hierarchical clustering (Figure 6) was further used to display groupings and make class distinctions. The two control groups clustered together as expected and showed a distinct trend relative to the other exposed groups. The lowest dose of radiation (0.5 Gy α-particle) also clustered with the unexposed groups. The next largest classification comprised the remaining exposure groups, in which the 2 Gy X-ray, 1.0 and 1.5 Gy α-particle and 5 and 10 Gy X-ray were classified further from the controls in order of descending similarity respectively. The subsequent clustering of the 1.0 and 1.5 Gy α-particle exposure and the 5 and 10 Gy X-ray exposure together suggests that it is possible to make distinctions between high X-ray radiation doses and α-particle doses using a clustering algorithm.


Identification of gene-based responses in human blood cells exposed to alpha particle radiation.

Chauhan V, Howland M, Wilkins R - BMC Med Genomics (2014)

Median based hierarchical clustering dataset to determine common groupings of samples and genes. Dataset is obtained from qPCR results in isolated white blood cells exposed to α-particle and X-ray radiation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4128605&req=5

Figure 6: Median based hierarchical clustering dataset to determine common groupings of samples and genes. Dataset is obtained from qPCR results in isolated white blood cells exposed to α-particle and X-ray radiation.
Mentions: WBCs were isolated from 12 healthy individuals and exposed to α-particles and X-rays. Total white blood cell counts were typically in the range of 5-10 × 106 cells/mL. The viability of the cells was assessed using the Trypan Blue viability assay pre- and post-irradiation. The cells remained viable (above 98%) and no significant changes in blood cell counts or populations subsets were observed post-irradiation relative to unirradiated cells (Table 4). Twenty-four hours after irradiation, RNA was extracted and reverse transcribed to cDNA. A comparison of the differential gene responses obtained from the qPCR of WBCs and microarray analysis of PBMCs showed similar fold change and statistical significance for the majority of the 68 transcripts that were assessed (Table 5). These responding genes were compared to those obtained for X-ray exposed cells. Box-plots of the responding genes from the WBC qPCR dataset allowed for a visual comparison of the two radiation types and the range in inter-individual variability between transcripts (Figure 5). Overall, all genes responsive in α-particle treated cells were also observed to be expressed in X-irradiated cells. The data displayed minimal variability between control treatment groups under varied radiation exposure conditions. Furthermore, the majority of genes displayed dose-response trends for both α-particle and X-ray radiation. Hierarchical clustering (Figure 6) was further used to display groupings and make class distinctions. The two control groups clustered together as expected and showed a distinct trend relative to the other exposed groups. The lowest dose of radiation (0.5 Gy α-particle) also clustered with the unexposed groups. The next largest classification comprised the remaining exposure groups, in which the 2 Gy X-ray, 1.0 and 1.5 Gy α-particle and 5 and 10 Gy X-ray were classified further from the controls in order of descending similarity respectively. The subsequent clustering of the 1.0 and 1.5 Gy α-particle exposure and the 5 and 10 Gy X-ray exposure together suggests that it is possible to make distinctions between high X-ray radiation doses and α-particle doses using a clustering algorithm.

Bottom Line: Microarray technology was employed to identify transcripts that were differentially expressed relative to unirradiated cells 24 hours post-exposure.Twenty-nine genes were common to all doses with expression levels ranging from 2-10 fold relative to control treatment group.This 29 gene panel was responsive in the α-particle exposed WBCs and was shown to exhibit differential fold-changes compared to X-irradiated cells, though no α-particle specific transcripts were identified.

View Article: PubMed Central - HTML - PubMed

Affiliation: Consumer and Clinical Radiation Protection Bureau, Healthy Environment and Consumer Safety Branch, Health Canada, 775 Brookfield Road, PL 6303B, Ottawa, ON K1A 1C1, Canada. Vinita.chauhan@hc-sc.gc.ca.

ABSTRACT

Background: The threat of a terrorist-precipitated nuclear event places humans at danger for radiological exposures. Isotopes which emit alpha (α)-particle radiation pose the highest risk. Currently, gene expression signatures are being developed for radiation biodosimetry and triage with respect to ionizing photon radiation. This study was designed to determine if similar gene expression profiles are obtained after exposures involving α-particles.

Methods: Peripheral blood mononuclear cells (PBMCs) were used to identify sensitive and robust gene-based biomarkers of α-particle radiation exposure. Cells were isolated from healthy individuals and were irradiated at doses ranging from 0-1.5 Gy. Microarray technology was employed to identify transcripts that were differentially expressed relative to unirradiated cells 24 hours post-exposure. Statistical analysis identified modulated genes at each of the individual doses.

Results: Twenty-nine genes were common to all doses with expression levels ranging from 2-10 fold relative to control treatment group. This subset of genes was further assessed in independent complete white blood cell (WBC) populations exposed to either α-particles or X-rays using quantitative real-time PCR. This 29 gene panel was responsive in the α-particle exposed WBCs and was shown to exhibit differential fold-changes compared to X-irradiated cells, though no α-particle specific transcripts were identified.

Conclusion: Current gene panels for photon radiation may also be applicable for use in α-particle radiation biodosimetry.

Show MeSH
Related in: MedlinePlus