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Ferrata Storti Foundation
Haematologica 2022 Volume 107(2):446-456
Successful gene therapy of Diamond-Blackfan anemia in a mouse model and human CD34+ cord blood hematopoietic stem cells using a clinically applicable lentiviral vector
Yang Liu,1 Maria Dahl,1 Shubhranshu Debnath,1 Michael Rothe,2 Emma M. Smith,1 Tan Hooi Min Grahn,1 Sarah Warsi,1 Jun Chen,1 Johan Flygare,1 Axel Schambach2,3 and Stefan Karlsson1
1Molecular Medicine and Gene Therapy, Lund Stem Cell Center, Lund University, Lund, Sweden; 2Institute of Experimental Hematology, Hannover Medical School, Hannover, Germany; and 3Division of Hematology/Oncology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
ABSTRACT
Diamond-Blackfan anemia (DBA) is an inherited bone marrow fail- ure disorder in which pure red blood cell aplasia is associated with physical malformations and a predisposition to cancer. Twenty- five percent of patients with DBA have mutations in a gene encoding ribo- somal protein S19 (RPS19). Our previous proof-of-concept studies demon- strated that DBA phenotype could be successfully treated using lentiviral vectors in Rps19-deficient DBA mice. In our present study, we developed a clinically applicable single gene, self-inactivating lentiviral vector, con- taining the human RPS19 cDNA driven by the human elongation factor 1a short promoter, which can be used for clinical gene therapy development for RPS19-deficient DBA. We examined the efficacy and safety of the vec- tor in a Rps19-deficient DBA mouse model and in human primary RPS19- deficient CD34+ cord blood cells. We observed that transduced Rps19-defi- cient bone marrow cells could reconstitute mice long-term and rescue the bone marrow failure and severe anemia observed in Rps19-deficient mice, with a low risk of mutagenesis and a highly polyclonal insertion site pat- tern. More importantly, the vector can also rescue impaired erythroid dif- ferentiation in human primary RPS19-deficient CD34+ cord blood hematopoietic stem cells. Collectively, our results demonstrate the efficacy and safety of using a clinically applicable lentiviral vector for the successful treatment of Rps19-deficient DBA in a mouse model and in human pri- mary CD34+ cord blood cells. These findings show that this vector can be used to develop clinical gene therapy for RPS19-deficient DBA patients.
Introduction
Diamond-Blackfan anemia (DBA) is a congenital bone marrow (BM) failure dis- order with erythroid hypoplasia that presents early in infancy.1-3 The classic hema- tologic profile of DBA consists of macrocytic anemia with reticulocytopenia, nor- mal or decreased levels of neutrophils, and a variable platelet count.3,4 Additionally, patients with DBA can also manifest with non-hematologic symp- toms such as physical abnormalities and a predisposition to cancer.2,5
The majority of DBA cases (60-70%) are caused by heterozygous loss-of-func- tion mutations in genes coding for ribosomal proteins (RP), resulting in functional RP haploinsufficiency.2 Recent studies have also identified mutations in erythroid transcriptional factors GATA1 and TSR2 (a direct binding partner of RPS26) as a cause of the DBA phenotype.6-8 Mutations in RPS19 are the most common alter- ations among patients with putative causal mutations, contributing to over 25% of cases.2 The main therapeutic option for DBA patients is corticosteroids, with more than 80% of the subjects responding well during early stages of treatment. However, half of these patients become non-responsive to corticosteroid therapy over prolonged treatment and have to be given blood transfusions.9 Importantly,
Cell Therapy & Immunotherapy
Correspondence:
STEFAN KARLSSON
stefan.karlsson@med.lu.se
YANG LIU
yang.liu@med.lu.se
Received: August 27, 2020. Accepted: December 23, 2020. Pre-published: January 14, 2021.
https://doi.org/10.3324/haematol.2020.269142 ©2022 Ferrata Storti Foundation
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