Microarray analysis of differentially expressed genes in mouse bone marrow tissues after ionizing radiation
Jin Ming Dai1, Dao Chun Sun, Ru Xian Lin
1Beijing Institute of Radiation Medicine, Beijing, China.
Purpose:
To identify differentially expressed genes in mouse bone marrow involved in radiation-induced injury.
Materials And Methods:
Microarray analysis was used to identify the differentially expressed genes and other techniques, e.g., polymerase chain reaction (PCR), western-blotting and antisense were also used to validate the results.
Results:
DNA microarray analysis demonstrated that the mRNA of 34 genes increased and 69 genes decreased in mouse bone marrow cells (BMC) from C57BL mice 6 h after a whole body dose of 6.5 Gy. These differentially expressed genes were involved in a number of processes including DNA replication/repair, proliferation/apoptosis, cell cycle control and RNA processing. In these experiments, a decline of the mammalian homolog Sir2a (an acronym for the silent mating type information regulation 2 homolog [SIRT1]) mRNA accompanied by an increase of P53 protein acetylation was observed in irradiated BMC. To determine whether the reduced SIRT1 is related to the higher acetylation status of P53 after irradiation, we designed and synthesized antisense oligonucleotides (AS) targeting human SIRT1 mRNA. Notably, AS transfection increased tumor protein 53 (P53) protein acetylation and bax-luciferase activity in human bone marrow stromal cell line (HS-5) after radiation. Furthermore, the AS transfer stimulated cell apoptosis in post-irradiation HS-5 cells.
Conclusion:
Ionizing radiation (IR) affects the expression of a series of genes including genes involved in G1/S transition and the P53 pathway. Among those, reduction of SIRT1 was seen to be involved in transactivation of P53.
Insights
Ionizing radiation alters gene expression in mouse bone marrow, impacting DNA repair and cell death pathways. Reduced silent mating type information regulation 2 homolog (SIRT1) levels correlate with increased P53 acetylation and apoptosis.
Area of Science:
- Molecular Biology
- Genomics
- Radiation Biology
Background:
- Ionizing radiation (IR) induces significant cellular damage.
- Understanding the molecular mechanisms of radiation-induced injury is crucial for developing protective strategies.
Purpose of the Study:
- To identify genes differentially expressed in mouse bone marrow following radiation exposure.
- To investigate the role of silent mating type information regulation 2 homolog (SIRT1) in radiation-induced bone marrow injury.
Main Methods:
- DNA microarray analysis to identify differentially expressed genes in mouse bone marrow cells (BMC) 6 hours post-irradiation.
- Validation using polymerase chain reaction (PCR), western-blotting, and antisense oligonucleotides (AS).
- Assessment of P53 protein acetylation and bax-luciferase activity in human bone marrow stromal cell line (HS-5).
Main Results:
- Microarray analysis revealed 34 upregulated and 69 downregulated genes in irradiated BMC.
- Differentially expressed genes are involved in DNA replication/repair, proliferation/apoptosis, cell cycle control, and RNA processing.
- Reduced SIRT1 mRNA levels and increased P53 protein acetylation were observed post-irradiation. AS targeting SIRT1 increased P53 acetylation, bax-luciferase activity, and apoptosis in HS-5 cells.
Conclusions:
- Ionizing radiation impacts gene expression, particularly affecting the G1/S transition and P53 pathways.
- SIRT1 downregulation is implicated in the transactivation of P53 following radiation exposure.
- Targeting SIRT1 may represent a therapeutic strategy for mitigating radiation-induced bone marrow damage.
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