Radiation-induced genomic instability in immortalized haemopoietic stem cells

Abstract Background Radiation-induced rectal epithelial damage is a very common side effect of pelvic radiotherapy and often compromise the life quality and treatment outcome in patients with pelvic malignancies. Unlike small bowel and colon, effect of radiation in rectal stem cells has not been explored extensively. Here we demonstrate that Lgr5-positive rectal stem cells are radiosensitive and organoid-based transplantation of rectal stem cells mitigates radiation damage in rectum. Methods C57Bl6 male mice (JAX) at 24 h were exposed to pelvic irradiation (PIR) to determine the radiation effect in pelvic epithelium. Effect of PIR on Lgr5-positive rectal stem cells (RSCs) was determined in Lgr5-EGFP-Cre-ERT2 mice exposed to PIR. Effect of PIR or clinically relevant fractionated PIR on regenerative response of Lgr5-positive RSCs was examined by lineage tracing assay using Lgr5-eGFP-IRES-CreERT2; Rosa26-CAG-tdTomato mice with tamoxifen administration to activate Cre recombinase and thereby marking the ISC and their respective progeny. Ex vivo three-dimensional organoid cultures were developed from Lgr5-EGFP-Cre-ERT2 mice. Organoid growth was determined by quantifying the budding crypt/total crypt ratio. Organoids from Lgr5-EGFP-ires-CreERT2-TdT mice were transplanted in C57Bl6 male mice exposed to PIR. Engraftment and repopulation of Lgr5-positive RSCs were determined after tamoxifen administration to activate Cre recombinase in recipient mice. Statistical analysis was performed using Log-rank (Mantel-Cox) test and paired two-tail t test. Result Exposure to pelvic irradiation significantly damaged rectal epithelium with the loss of Lgr5+ve rectal stem cells. Radiosensitivity of rectal epithelium was also observed with exposure to clinically relevant fractionated pelvic irradiation. Regenerative capacity of Lgr5+ve rectal stem cells was compromised in response to fractionated pelvic irradiation. Ex vivo organoid study demonstrated that Lgr5+ve rectal stem cells are sensitive to both single and fractionated radiation. Organoid-based transplantation of Lgr5+ve rectal stem cells promotes repair and regeneration of rectal epithelium. Conclusion Lgr5-positive rectal stem cells are radiosensitive and contribute to radiation-induced rectal epithelial toxicity. Transplantation of Lgr5-positive rectal stem cells mitigates radiation-induced rectal injury and promotes repair and regeneration process in rectum.

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Will mesenchymal stem cells be future directions for treating radiation-induced skin injury?

Stem Cell Research & Therapy ◽

10.1186/s13287-021-02261-5 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Zhuoqun Fang ◽

Penghong Chen ◽

Shijie Tang ◽

Aizhen Chen ◽

Chaoyu Zhang ◽

...

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Malignant Tumors ◽

Skin Injury ◽

Future Directions ◽

Cytokines And Chemokines ◽

Radiation Induced ◽

The Common ◽

Apoptotic Activity ◽

Different Sources

AbstractRadiation-induced skin injury (RISI) is one of the common serious side effects of radiotherapy (RT) for patients with malignant tumors. Mesenchymal stem cells (MSCs) are applied to RISI repair in some clinical cases series except some traditional options. Though direct replacement of damaged cells may be achieved through differentiation capacity of MSCs, more recent data indicate that various cytokines and chemokines secreted by MSCs are involved in synergetic therapy of RISI by anti-inflammatory, immunomodulation, antioxidant, revascularization, and anti-apoptotic activity. In this paper, we not only discussed different sources of MSCs on the treatment of RISI both in preclinical studies and clinical trials, but also summarized the applications and mechanisms of MSCs in other related regenerative fields.

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Mesenchymal Stem Cell-Derived Exosomes: Biological Function and Their Therapeutic Potential in Radiation Damage

Cells ◽

10.3390/cells10010042 ◽

2020 ◽

Vol 10 (1) ◽

pp. 42

Author(s):

Xiaoyu Pu ◽

Siyang Ma ◽

Yan Gao ◽

Tiankai Xu ◽

Pengyu Chang ◽

...

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Stem Cell ◽

Mesenchymal Stem Cell ◽

Radiation Damage ◽

Therapeutic Potential ◽

Damage Model ◽

Bioactive Substances ◽

Radiation Induced ◽

Insight Into

Radiation-induced damage is a common occurrence in cancer patients who undergo radiotherapy. In this setting, radiation-induced damage can be refractory because the regeneration responses of injured tissues or organs are not well stimulated. Mesenchymal stem cells have become ideal candidates for managing radiation-induced damage. Moreover, accumulating evidence suggests that exosomes derived from mesenchymal stem cells have a similar effect on repairing tissue damage mainly because these exosomes carry various bioactive substances, such as miRNAs, proteins and lipids, which can affect immunomodulation, angiogenesis, and cell survival and proliferation. Although the mechanisms by which mesenchymal stem cell-derived exosomes repair radiation damage have not been fully elucidated, we intend to translate their biological features into a radiation damage model and aim to provide new insight into the management of radiation damage.

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