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Updated: May 4, 2026
Author Spotlight: Analyzing Bone Marrow Microenvironment in Murine Hematological Malignancies
Published on: November 10, 2023
Radiologic differences between bone marrow stromal and hematopoietic progenitor cell lines from Fanconi Anemia
Hebist Berhane1, Michael W Epperly, Julie Goff
1a Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15213;
Abstract:
FancD2 plays a central role in the human Fanconi anemia DNA damage response (DDR) pathway. Fancd2(-/-) mice exhibit many features of human Fanconi anemia including cellular DNA repair defects. Whether the DNA repair defect in Fancd2(-/-) mice results in radiologic changes in all cell lineages is unknown. We measured stress of hematopoiesis in long-term marrow cultures and radiosensitivity in clonogenic survival curves, as well as comet tail intensity, total antioxidant stores and radiation-induced gene expression in hematopoietic progenitor compared to bone marrow stromal cell lines. We further evaluated radioprotection by a mitochondrial-targeted antioxidant GS-nitroxide, JP4-039. Hematopoiesis longevity in Fancd2(-/-) mouse long-term marrow cultures was diminished and bone marrow stromal cell lines were radiosensitive compared to Fancd2(+/+) stromal cells (Fancd2(-/-) D0 = 1.4 ± 0.1 Gy, ñ = 5.0 ± 0.6 vs. Fancd2(+/+) D0 = 1.6 ± 0.1 Gy, ñ = 6.7 ± 1.6), P = 0.0124 for D0 and P = 0.0023 for ñ, respectively). In contrast, Fancd2(-/-) IL-3-dependent hematopoietic progenitor cells were radioresistant (D0 = 1.71 ± 0.04 Gy and ñ = 5.07 ± 0.52) compared to Fancd2(+/+) (D0 = 1.39 ± 0.09 Gy and ñ = 2.31 ± 0.85, P = 0.001 for D0). CFU-GM from freshly explanted Fancd2(-/-) marrow was also radioresistant. Consistent with radiosensitivity, irradiated Fancd2(-/-) stromal cells had higher DNA damage by comet tail intensity assay compared to Fancd2(+/+) cells (P < 0.0001), slower DNA damage recovery, lower baseline total antioxidant capacity, enhanced radiation-induced depletion of antioxidants, and increased CDKN1A-p21 gene transcripts and protein. Consistent with radioresistance, Fancd2(-/-) IL-3-dependent hematopoietic cells had higher baseline and post irradiation total antioxidant capacity. While, there was no detectable alteration of radiation-induced cell cycle arrest with Fancd2(-/-) stromal cells, hematopoietic progenitor cells showed reduced G2/M cell cycle arrest. The absence of the mouse Fancd2 gene product confers radiosensitivity to bone marrow stromal but not hematopoietic progenitor cells.
Insights
The absence of the FancD2 protein makes mouse bone marrow stromal cells sensitive to radiation, while hematopoietic progenitor cells become radioresistant. This study investigates DNA repair defects and antioxidant capacity in Fanconi anemia mouse models.
Area of Science:
- Molecular Biology
- Genetics
- Radiobiology
Background:
- Fanconi anemia (FA) is a genetic disorder characterized by DNA damage response (DDR) pathway defects.
- FancD2 protein is crucial for the FA-DDR pathway, and its absence in mice (Fancd2(-/-)) mimics human FA cellular phenotypes.
- The differential impact of Fancd2 deficiency on radiosensitivity across various cell types remains largely uncharacterized.
Purpose of the Study:
- To investigate the differential radiosensitivity of hematopoietic progenitor cells versus bone marrow stromal cells in Fancd2(-/-) mice.
- To elucidate the underlying mechanisms, including DNA repair efficiency, antioxidant capacity, and cell cycle regulation.
- To assess the potential radioprotective effects of a novel mitochondrial-targeted antioxidant.
Main Methods:
- Long-term marrow cultures to assess hematopoietic stress.
- Clonogenic survival assays to determine radiosensitivity (D0 and ñ values).
- Comet assay for DNA damage, antioxidant capacity measurements, and gene expression analysis (CDKN1A-p21) following irradiation.
Main Results:
- Fancd2(-/-) bone marrow stromal cells exhibited radiosensitivity and impaired DNA damage repair compared to wild-type controls.
- Conversely, Fancd2(-/-) hematopoietic progenitor cells demonstrated radioresistance, with higher baseline and post-irradiation antioxidant capacity.
- Reduced G2/M cell cycle arrest was observed in Fancd2(-/-) hematopoietic progenitor cells post-irradiation.
Conclusions:
- The absence of Fancd2 confers distinct radiosensitivity profiles to different bone marrow cell lineages.
- Bone marrow stromal cells become radiosensitive, while hematopoietic progenitor cells gain radioresistance due to Fancd2 deficiency.
- Differential regulation of DNA repair, antioxidant status, and cell cycle response underlies these observed radiosensitivity variations.
