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Hematopoietic stem cell-targeted neonatal gene therapy with a clinically applicable lentiviral vector corrects osteopetrosis in oc/oc Mice

Löfvall, Henrik LU orcid ; Rothe, Michael ; Schambach, Axel ; Henriksen, Kim ; Richter, Johan LU and Moscatelli, Ilana LU (2019) In Human Gene Therapy 30(11). p.1395-1404
Abstract

Infantile malignant osteopetrosis (IMO) is an autosomal recessive disorder characterized by nonfunctional osteoclasts. Approximately 50% of the patients have mutations in the TCIRG1 gene, encoding for a subunit of the osteoclast proton pump. Gene therapy represents a potential alternative treatment to allogeneic stem cell transplantation for IMO. The oc/oc mouse is a model of IMO characterized by a 1,500 bp deletion in the TCIRG1 gene, severe osteopetrosis, and a life span of only 3 weeks. Here we show that the osteopetrotic phenotype in oc/oc mice can be reversed by hematopoietic stem cell-targeted gene therapy with a clinically applicable lentiviral vector expressing a wild-type form of human TCIRG1 under the mammalian promoter... (More)

Infantile malignant osteopetrosis (IMO) is an autosomal recessive disorder characterized by nonfunctional osteoclasts. Approximately 50% of the patients have mutations in the TCIRG1 gene, encoding for a subunit of the osteoclast proton pump. Gene therapy represents a potential alternative treatment to allogeneic stem cell transplantation for IMO. The oc/oc mouse is a model of IMO characterized by a 1,500 bp deletion in the TCIRG1 gene, severe osteopetrosis, and a life span of only 3 weeks. Here we show that the osteopetrotic phenotype in oc/oc mice can be reversed by hematopoietic stem cell-targeted gene therapy with a clinically applicable lentiviral vector expressing a wild-type form of human TCIRG1 under the mammalian promoter elongation factor 1α short (EFS-hT). oc/oc c-kit+ fetal liver cells transduced with EFS-hT were transplanted into sublethally irradiated oc/oc mice by temporal vein injection 1 day after birth. A total of 9 of 12 mice survived long term (19-25 weeks) with evidence of tooth eruption, uncharacteristic of oc/oc mice. Splenocytes were harvested 19-25 weeks after transplantation and differentiated into osteoclasts on bone slices to assess resorption and on plastic to assess TCIRG1 protein expression. Vector-corrected osteoclasts showed human TCIRG1 expression by Western blot. CTX-I release relative to that mediated by oc/oc-derived osteoclasts increased 8-239-fold. Resorption pits on bone slices were observed for osteoclasts derived from 7/9 surviving transplanted oc/oc mice. Histopathology of the bones of surviving animals showed varying degrees of rescued phenotype, the majority with almost full correction. The average vector copy number per cell in the bone marrow was 1.8 ± 0.5. Overall, 75% of transplanted mice exhibited long-term survival and marked reversal of the osteopetrotic bone phenotype. These findings represent a significant step toward the clinical application of gene therapy for IMO.

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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
gene transfer to hematopoietic stem cells, lentiviral vectors, oc/oc, osteopetrosis, TCIRG1
in
Human Gene Therapy
volume
30
issue
11
pages
10 pages
publisher
Mary Ann Liebert, Inc.
external identifiers
  • pmid:31179768
  • scopus:85074735714
ISSN
1043-0342
DOI
10.1089/hum.2019.047
language
English
LU publication?
yes
id
25aff048-e729-4f94-8fe3-5ee930a10fb1
date added to LUP
2019-11-29 14:05:54
date last changed
2024-05-29 04:33:35
@article{25aff048-e729-4f94-8fe3-5ee930a10fb1,
  abstract     = {{<p>Infantile malignant osteopetrosis (IMO) is an autosomal recessive disorder characterized by nonfunctional osteoclasts. Approximately 50% of the patients have mutations in the TCIRG1 gene, encoding for a subunit of the osteoclast proton pump. Gene therapy represents a potential alternative treatment to allogeneic stem cell transplantation for IMO. The oc/oc mouse is a model of IMO characterized by a 1,500 bp deletion in the TCIRG1 gene, severe osteopetrosis, and a life span of only 3 weeks. Here we show that the osteopetrotic phenotype in oc/oc mice can be reversed by hematopoietic stem cell-targeted gene therapy with a clinically applicable lentiviral vector expressing a wild-type form of human TCIRG1 under the mammalian promoter elongation factor 1α short (EFS-hT). oc/oc c-kit<sup>+</sup> fetal liver cells transduced with EFS-hT were transplanted into sublethally irradiated oc/oc mice by temporal vein injection 1 day after birth. A total of 9 of 12 mice survived long term (19-25 weeks) with evidence of tooth eruption, uncharacteristic of oc/oc mice. Splenocytes were harvested 19-25 weeks after transplantation and differentiated into osteoclasts on bone slices to assess resorption and on plastic to assess TCIRG1 protein expression. Vector-corrected osteoclasts showed human TCIRG1 expression by Western blot. CTX-I release relative to that mediated by oc/oc-derived osteoclasts increased 8-239-fold. Resorption pits on bone slices were observed for osteoclasts derived from 7/9 surviving transplanted oc/oc mice. Histopathology of the bones of surviving animals showed varying degrees of rescued phenotype, the majority with almost full correction. The average vector copy number per cell in the bone marrow was 1.8 ± 0.5. Overall, 75% of transplanted mice exhibited long-term survival and marked reversal of the osteopetrotic bone phenotype. These findings represent a significant step toward the clinical application of gene therapy for IMO.</p>}},
  author       = {{Löfvall, Henrik and Rothe, Michael and Schambach, Axel and Henriksen, Kim and Richter, Johan and Moscatelli, Ilana}},
  issn         = {{1043-0342}},
  keywords     = {{gene transfer to hematopoietic stem cells; lentiviral vectors; oc/oc; osteopetrosis; TCIRG1}},
  language     = {{eng}},
  number       = {{11}},
  pages        = {{1395--1404}},
  publisher    = {{Mary Ann Liebert, Inc.}},
  series       = {{Human Gene Therapy}},
  title        = {{Hematopoietic stem cell-targeted neonatal gene therapy with a clinically applicable lentiviral vector corrects osteopetrosis in oc/oc Mice}},
  url          = {{http://dx.doi.org/10.1089/hum.2019.047}},
  doi          = {{10.1089/hum.2019.047}},
  volume       = {{30}},
  year         = {{2019}},
}