@article{Capo_Penna_Merelli_Barcella_Scala_Basso-Ricci_Draghici_Palagano_Zonari_Desantis_Uva_Cusano_Sergi Sergi_Crisafulli_Moshous_Stepensky_Drabko_Kaya_Unal_Gezdirici_Menna_Serafini_Aiuti_Locatelli_Carlo-Stella_Schulz_Ficara_Sobacchi_Gentner_Villa_2021, place={Pavia, Italy}, title={Expanded circulating hematopoietic stem/progenitor cells as novel cell source for the treatment of TCIRG1 osteopetrosis}, volume={106}, url={https://haematologica.org/article/view/9619}, DOI={10.3324/haematol.2019.238261}, abstractNote={<p>Allogeneic hematopoietic stem cell transplantation is the treatment of choice for autosomal recessive osteopetrosis caused by defects in the TCIRG1 gene. Despite recent progress in conditioning, a relevant number of patients are not eligible for allogeneic stem cell transplantation because of the severity of the disease and significant transplant-related morbidity. We exploited peripheral CD34+ cells, known to circulate at high frequency in the peripheral blood of TCIRG1-deficient patients, as a novel cell source for autologous transplantation of gene corrected cells. Detailed phenotypical analysis showed that circulating CD34+ cells have a cellular composition that resembles bone marrow, supporting their use in gene therapy protocols. Transcriptomic profile revealed enrichment in genes expressed by hematopoietic stem and progenitor cells (HSPCs). To overcome the limit of bone marrow harvest/ HSPC mobilization and serial blood drawings in TCIRG1 patients, we applied UM171-based ex-vivo expansion of HSPCs coupled with lentiviral gene transfer. Circulating CD34+ cells from TCIRG1-defective patients were transduced with a clinically-optimized lentiviral vector (LV) expressing TCIRG1 under the control of phosphoglycerate promoter and expanded ex vivo. Expanded cells maintained long-term engraftment capacity and multi-lineage repopulating potential when transplanted in vivo both in primary and secondary NSG recipients. Moreover, when CD34+ cells were differentiated in vitro, genetically corrected osteoclasts resorbed the bone efficiently. Overall, we provide evidence that expansion of circulating HSPCs coupled to gene therapy can overcome the limit of stem cell harvest in osteopetrotic patients, thus opening the way to future gene-based treatment of skeletal diseases caused by bone marrow fibrosis.</p&gt;}, number={1}, journal={Haematologica}, author={Capo, Valentina and Penna, Sara and Merelli, Ivan and Barcella, Matteo and Scala, Serena and Basso-Ricci, Luca and Draghici, Elena and Palagano, Eleonora and Zonari, Erika and Desantis, Giacomo and Uva, Paolo and Cusano, Roberto and Sergi Sergi, Lucia and Crisafulli, Laura and Moshous, Despina and Stepensky, Polina and Drabko, Katarzyna and Kaya, Zühre and Unal, Ekrem and Gezdirici, Alper and Menna, Giuseppe and Serafini, Marta and Aiuti, Alessandro and Locatelli, Silvia Laura and Carlo-Stella, Carmelo and Schulz, Ansgar S. and Ficara, Francesca and Sobacchi, Cristina and Gentner, Bernhard and Villa, Anna}, year={2021}, month={Jan.}, pages={74-86} }