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Updated: Dec 30, 2025
Retroviral Transduction of Bone Marrow Progenitor Cells to Generate T-cell Receptor Retrogenic Mice
Published on: July 11, 2016
Generation of an immunodeficient mouse model of tcirg1-deficient autosomal recessive osteopetrosis
Eleonora Palagano1,2, Sharon Muggeo1,2, Laura Crisafulli1,2
1CNR-IRGB, Milan Unit, via Fantoli 16/15, 20138 Milan, Italy.
Background:
Autosomal recessive osteopetrosis is a rare skeletal disorder with increased bone density due to a failure in osteoclast bone resorption. In most cases, the defect is cell-autonomous, and >50% of patients bear mutations in the TCIRG1 gene, encoding for a subunit of the vacuolar proton pump essential for osteoclast resorptive activity. The only cure is hematopoietic stem cell transplantation, which corrects the bone pathology by allowing the formation of donor-derived functional osteoclasts. Therapeutic approaches using patient-derived cells corrected ex vivo through viral transduction or gene editing can be considered, but to date functional rescue cannot be demonstrated in vivo because a relevant animal model for xenotransplant is missing.
Methods:
We generated a new mouse model, which we named NSG oc/oc, presenting severe autosomal recessive osteopetrosis owing to the Tcirg1 mutation, and profound immunodeficiency caused by the NSG background. We performed neonatal murine bone marrow transplantation and xenotransplantation with human CD34+ cells.
Results:
We demonstrated that neonatal murine bone marrow transplantation rescued NSG oc/oc mice, in line with previous findings in the oc/oc parental strain and with evidence from clinical practice in humans. Importantly, we also demonstrated human cell chimerism in the bone marrow of NSG oc/oc mice transplanted with human CD34+ cells. The severity and rapid progression of the disease in the mouse model prevented amelioration of the bone pathology; nevertheless, we cannot completely exclude that minor early modifications of the bone tissue might have occurred.
Conclusion:
Our work paves the way to generating an improved xenograft model for in vivo evaluation of functional rescue of patient-derived corrected cells. Further refinement of the newly generated mouse model will allow capitalizing on it for an optimized exploitation in the path to novel cell therapies.
Insights
A new mouse model with severe osteopetrosis and immunodeficiency was created. This model enables the in vivo evaluation of gene-corrected patient cells for potential new cell therapies.
Area of Science:
- Genetics and Molecular Biology
- Immunology
- Hematology
Background:
- Autosomal recessive osteopetrosis is a rare skeletal disorder characterized by increased bone density due to impaired osteoclast function.
- Mutations in the TCIRG1 gene, crucial for osteoclast activity, cause over 50% of these cases.
- Hematopoietic stem cell transplantation is the only cure, replacing defective osteoclasts with functional donor cells.
Purpose of the Study:
- To develop a novel mouse model for evaluating in vivo therapeutic strategies for osteopetrosis.
- To establish a xenotransplantation model for assessing patient-derived corrected cells.
Main Methods:
- Generation of the NSG oc/oc mouse model with a Tcirg1 mutation and NSG immunodeficient background.
- Neonatal murine bone marrow transplantation and xenotransplantation using human CD34+ cells.
Main Results:
- Neonatal bone marrow transplantation rescued the NSG oc/oc mice, confirming the model's utility.
- Human cell chimerism was successfully demonstrated in the bone marrow of NSG oc/oc mice after xenotransplantation.
- The severe disease progression in the model limited observable amelioration of bone pathology, though minor early changes cannot be ruled out.
Conclusions:
- The developed NSG oc/oc mouse model serves as a crucial platform for in vivo evaluation of gene-corrected patient cells.
- Further refinement of this model will facilitate the optimization of novel cell therapies for osteopetrosis.
