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Radiation-induced molecular alterations after whole body irradiation in a mouse model

ABSTRACT: Long non-coding RNAs (lncRNAs) are emerging as key molecules in regulating many biological processes and have been implicated in development and disease pathogenesis. Biomarkers of cancer and normal tissue response to treatment are of great interest in precision medicine and for public health and medical management of disasters such as assessing radiation injury following accidental or intentional exposure. Circulating and functional RNAs, including microRNAs (miRNAs) and lncRNAs, in whole blood and other body fluids represent potential valuable candidates as biomarkers. Early prediction of possible acute, intermediate, and delayed effects of radiation exposure will enable timely therapeutic interventions. To address whether lncRNAs could serve as biomarkers for radiation bio-dosimetry, we performed whole genome transcriptome analysis in a mouse model after whole body irradiation. Differential lncRNA expression patterns were evaluated at 16-, 24-, and 48-hour time points post irradiation in total RNA isolated from whole blood of mice exposed to 1, 2, 4, 8, and 12 Gy of gamma-rays. Sham irradiated animals served as controls. Significant alterations in the expression patterns of lncRNAs were observed after different radiation doses at the various timepoints. We identified several lncRNAs known for DNA damage response as well as immune response as radiation induced biomarkers. Long non-coding RNA targets of tumor protein 53 (P53), Trp53cor1, Dino, Pvt1 and Tug1 and an upstream regulator of p53, Meg3 were altered in response to radiation. Gm14005 (Morrbid) and Tmevpg1 were regulated by radiation across all time points and doses. These two lncRNAs have important potential as blood based radiation biomarkers; Gm14005 (Morrbid) has recently been shown to play a key role in inflammatory response while Tmevpg1 has been implicated in the regulation of interferon-gamma. Precise molecular biomarkers will not only enable the development and effective use of medical countermeasures but also may be used to detect and circumvent or mitigate normal tissue injury in cancer radiotherapy treatments.

ORGANISM(S): Mus musculus

PROVIDER: GSE104121 | GEO | 2018/05/31

REPOSITORIES: GEO

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Project description:Rapid and reliable methods for conducting biological dosimetry are a necessity in the event of a large-scale nuclear event. Timely and accurate methods are thus critical in order to correctly evaluate and identify radiation dose exposure and triage appropriately. Alterations in microRNAs (miRNAs), small non-coding RNAs of 19-22 nucleotides, have been reported in cells/tumors subjected to radiation exposure, implying that miRNAs play an important role in cellular stress response to radiation. To examine the possibility of using microRNA as stable blood based biomarkers for radiation response, we have used microRNA microarray analysis. Differential microRNA expression pattern was evaluated (>1.5 fold and p value <0.05) at 6, 24, 48 h and 7day time points in whole blood from mice exposed to 2, 4, 8, 12 and 15Gy irradiation. More differentially expressed microRNAs (up and down) were seen after higher dose of radiation and later time points. Among the significantly upregulated microRNAs, miR-193b-3p and mir-92a-3p were consistently upregulated for all doses at earlier time points. We observed significant downregulation of several members of the miR-17 family (miR-17-5p, miR-20a-5p, miR-93-5p and miR-106b-5p) in response to radiation from 2 Gy onwards at 24 h, 48 h and at higher doses for the 7 d time-point. Whereas miR-34a, which regulates G1/S cell cycle checkpoint activation in response to radiation induced DNA damage, showed consistent upregulation for both low and high doses at later time points up to one week after exposure. Significant down regulation of miR-150-5p, miR-101, miR-140, miR-29b, miR-193b and miR-30 family of microRNAs were seen for low and high doses of radiation for all time points up to 7day. Low dose radiation (2Gy) exposure also resulted in down regulation of a group of microRNAs after one week; whereas these microRNAs showed upregulation after high dose exposure (8, 12 and 15Gy) up to one week. This dose and time dependent differential microRNA expression pattern might be useful in evaluating radiation response during and after therapeutic radiation treatment in patients. Ultimately, a combined approach of identifying biomarkers by assessing functional miRNA, target mRNAs and the resulting proteins to assess radiation exposure after mass-casualty incidents could provide a valuable tool in developing and implementing effective and timely medical countermeasures.

Project description:Development of radiation medical countermeasures under the U.S. Food and Drug Administration Animal Rule requires the capability to translate an effective animal to human drug dose. One method of human dose translation is using a biomarker and determining drug doses that modulate the biomarker to the desired level. BIO 300 Oral Powder (BIO 300) is a prophylactic radiation medical countermeasure that is currently being developed following the Animal Rule. The present study aimed to identify biomarkers that can be used for human dose conversion by conducting transcriptomics of whole blood collected from BIO 300-treated CD2F1 mice in the presence and absence of total-body irradiation (TBI). Mice were treated with vehicle or 50, 100 or 200 mg/kg BIO 300, twice daily, for 6 days. Whole blood samples were collected 24 and 48 h after the last dose of the drug. Animals were also treated with vehicle or 200 mg/kg BIO 300 for 6 days prior to 9.2 Gy TBI 24 h after the last dose, with blood collection 24 h after irradiation. RNA sequencing demonstrated 100 – 200 mg/kg doses caused significantly more differential gene expression at 48 h post-drug dose compared to 50 mg/kg. Pathway analysis of the transcriptome profile from vehicle-treated/radiation-exposed mice revealed that many inflammatory signaling pathways were activated in these animals. Signaling pathways enriched in BIO 300-treated/TBI mice were involved in cellular stress and immune response and were predicted to be inhibited. We also identified pathways that were in inverse states (activation/inhibition) in vehicle and BIO 300-treated mice with TBI. There were two pathways specifically activated in vehicle-treated animals with TBI and inhibited in BIO 300-treated animals (with or without TBI), pathogen-induced cytokine storm signaling and S100 family signaling. In comparison to previously published human data, pulmonary fibrosis idiopathic signaling and wound healing signaling were enriched in healthy volunteers treated with BIO 300 and BIO 300-treated mice with TBI. In all, four signaling pathways were identified that were activated in vehicle-treated animals exposed to total body radiation but inhibited in irradiated animals or healthy humans treated with BIO 300. These pathways should be explored to identify potential biomarkers of BIO 300 that can be used for human dose translation.

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Radiation-induced molecular alterations after whole body irradiation in a mouse model

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