Browsing by Subject "Adenosine deaminase"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Autologous Ex Vivo Lentiviral Gene Therapy for Adenosine Deaminase Deficiency
    (Massachusetts Medical Society, 2021-05-27) Kohn, Donald B.; Booth, Claire; Shaw, Kit L.; Xu-Bayford, Jinhua; Garabedian, Elizabeth; Trevisan, Valentina; Carbonaro-Sarracino, Denise A.; Soni, Kajal; Terrazas, Dayna; Snell, Katie; Ikeda, Alan; Leon-Rico, Diego; Moore, Theodore B.; Buckland, Karen F.; Shah, Ami J.; Gilmour, Kimberly C.; De Oliveira, Satiro; Rivat, Christine; Crooks, Gay M.; Izotova, Natalia; Tse, John; Adams, Stuart; Shupien, Sally; Ricketts, Hilory; Davila, Alejandra; Uzowuru, Chilenwa; Icreverzi, Amalia; Barman, Provaboti; Fernandez, Beatriz Campo; Hollis, Roger P.; Coronel, Maritess; Yu, Allen; Chun, Krista M.; Casas, Christian E.; Zhang, Ruixue; Arduini, Serena; Lynn, Frances; Kudari, Mahesh; Spezzi, Andrea; Zahn, Marco; Heimke, Rene; Labik, Ivan; Parrott, Roberta; Buckley, Rebecca H.; Reeves, Lilith; Cornetta, Kenneth; Sokolic, Robert; Hershfield, Michael; Schmidt, Manfred; Candotti, Fabio; Malech, Harry L.; Thrasher, Adrian J.; Gaspar, H. Bobby; Medicine, School of Medicine
    Background: Severe combined immunodeficiency due to adenosine deaminase (ADA) deficiency (ADA-SCID) is a rare and life-threatening primary immunodeficiency. Methods: We treated 50 patients with ADA-SCID (30 in the United States and 20 in the United Kingdom) with an investigational gene therapy composed of autologous CD34+ hematopoietic stem and progenitor cells (HSPCs) transduced ex vivo with a self-inactivating lentiviral vector encoding human ADA. Data from the two U.S. studies (in which fresh and cryopreserved formulations were used) at 24 months of follow-up were analyzed alongside data from the U.K. study (in which a fresh formulation was used) at 36 months of follow-up. Results: Overall survival was 100% in all studies up to 24 and 36 months. Event-free survival (in the absence of reinitiation of enzyme-replacement therapy or rescue allogeneic hematopoietic stem-cell transplantation) was 97% (U.S. studies) and 100% (U.K. study) at 12 months; 97% and 95%, respectively, at 24 months; and 95% (U.K. study) at 36 months. Engraftment of genetically modified HSPCs persisted in 29 of 30 patients in the U.S. studies and in 19 of 20 patients in the U.K. study. Patients had sustained metabolic detoxification and normalization of ADA activity levels. Immune reconstitution was robust, with 90% of the patients in the U.S. studies and 100% of those in the U.K. study discontinuing immunoglobulin-replacement therapy by 24 months and 36 months, respectively. No evidence of monoclonal expansion, leukoproliferative complications, or emergence of replication-competent lentivirus was noted, and no events of autoimmunity or graft-versus-host disease occurred. Most adverse events were of low grade. Conclusions: Treatment of ADA-SCID with ex vivo lentiviral HSPC gene therapy resulted in high overall and event-free survival with sustained ADA expression, metabolic correction, and functional immune reconstitution.
  • Thumbnail Image
    Item
    Long-term outcomes after gene therapy for adenosine deaminase severe combined immune deficiency
    (American Society of Hematology, 2021) Reinhardt, Bryanna; Habib, Omar; Shaw, Kit L.; Garabedian, Elizabeth; Carbonaro-Sarracino, Denise A.; Terrazas, Dayna; Fernandez, Beatriz Campo; De Oliveira, Satiro; Moore, Theodore B.; Ikeda, Alan K.; Engel, Barbara C.; Podsakoff, Gregory M.; Hollis, Roger P.; Fernandes, Augustine; Jackson, Connie; Shupien, Sally; Mishra, Suparna; Davila, Alejandra; Mottahedeh, Jack; Vitomirov, Andrej; Meng, Wenzhao; Rosenfeld, Aaron M.; Roche, Aoife M.; Hokama, Pascha; Reddy, Shantan; Everett, John; Wang, Xiaoyan; Luning Prak, Eline T.; Cornetta, Kenneth; Hershfield, Michael S.; Sokolic, Robert; De Ravin, Suk See; Malech, Harry L.; Bushman, Frederic D.; Candotti, Fabio; Kohn, Donald B.; Medical and Molecular Genetics, School of Medicine
    Patients lacking functional adenosine deaminase activity have severe combined immunodeficiency (ADA SCID), which can be treated with ADA enzyme replacement therapy (ERT), allogeneic hematopoietic stem cell transplantation (HSCT), or autologous HSCT with gene-corrected cells (gene therapy [GT]). A cohort of 10 ADA SCID patients, aged 3 months to 15 years, underwent GT in a phase 2 clinical trial between 2009 and 2012. Autologous bone marrow CD34+ cells were transduced ex vivo with the MND (myeloproliferative sarcoma virus, negative control region deleted, dl587rev primer binding site)-ADA gammaretroviral vector (gRV) and infused following busulfan reduced-intensity conditioning. These patients were monitored in a long-term follow-up protocol over 8 to 11 years. Nine of 10 patients have sufficient immune reconstitution to protect against serious infections and have not needed to resume ERT or proceed to secondary allogeneic HSCT. ERT was restarted 6 months after GT in the oldest patient who had no evidence of benefit from GT. Four of 9 evaluable patients with the highest gene marking and B-cell numbers remain off immunoglobulin replacement therapy and responded to vaccines. There were broad ranges of responses in normalization of ADA enzyme activity and adenine metabolites in blood cells and levels of cellular and humoral immune reconstitution. Outcomes were generally better in younger patients and those receiving higher doses of gene-marked CD34+ cells. No patient experienced a leukoproliferative event after GT, despite persisting prominent clones with vector integrations adjacent to proto-oncogenes. These long-term findings demonstrate enduring efficacy of GT for ADA SCID but also highlight risks of genotoxicity with gRVs.
  • Thumbnail Image
    Item
    Pair of Unusual GCN5 Histone Acetyltransferases and ADA2 Homologues in the Protozoan Parasite Toxoplasma gondii
    (American Society for Microbiology, 2006) Bhatti, Micah M.; Livingston, Meredith; Mullapudi, Nandita; Sullivan, William J., Jr.; Pharmacology and Toxicology, School of Medicine
    GCN5 is a histone acetyltransferase (HAT) essential for development in mammals and critical to stress responses in yeast. The protozoan parasite Toxoplasma gondii is a serious opportunistic pathogen. The study of epigenetics and gene expression in this ancient eukaryote has pharmacological relevance and may facilitate the understanding of these processes in higher eukaryotes. Here we show that the disruption of T. gondii GCN5 yields viable parasites, which were subsequently employed in a proteomics study to identify gene products affected by its loss. Promoter analysis of these TgGCN5-dependent genes, which were mostly parasite specific, reveals a conserved T-rich element. The loss of TgGCN5 does not attenuate virulence in an in vivo mouse model. We also discovered that T. gondii is the only invertebrate reported to date possessing a second GCN5 (TgGCN5-B). TgGCN5-B harbors a strikingly divergent N-terminal domain required for nuclear localization. Despite high homology between the HAT domains, the two TgGCN5s exhibit differing substrate specificities. In contrast to TgGCN5-A, which exclusively targets lysine 18 of H3, TgGCN5-B acetylates multiple lysines in the H3 tail. We also identify two ADA2 homologues that interact differently with the TgGCN5s. TgGCN5-B has the potential to compensate for TgGCN5-A, which probably arose from a gene duplication unique to T. gondii. Our work reveals an unexpected complexity in the GCN5 machinery of this primitive eukaryote.
  • Thumbnail Image
    Item
    Profiling neural editomes reveals a molecular mechanism to regulate RNA editing during development
    (Cold Spring Harbor Laboratory Press, 2021-01) Rajendren, Suba; Dhakal, Alfa; Vadlamani, Pranathi; Townsend, Jack; Deffit, Sarah N.; Hundley, Heather A.; Biology, School of Science
    Adenosine (A) to inosine (I) RNA editing contributes to transcript diversity and modulates gene expression in a dynamic, cell type-specific manner. During mammalian brain development, editing of specific adenosines increases, whereas the expression of A-to-I editing enzymes remains unchanged, suggesting molecular mechanisms that mediate spatiotemporal regulation of RNA editing exist. Herein, by using a combination of biochemical and genomic approaches, we uncover a molecular mechanism that regulates RNA editing in a neural- and development-specific manner. Comparing editomes during development led to the identification of neural transcripts that were edited only in one life stage. The stage-specific editing is largely regulated by differential gene expression during neural development. Proper expression of nearly one-third of the neurodevelopmentally regulated genes is dependent on adr-2, the sole A-to-I editing enzyme in C. elegans However, we also identified a subset of neural transcripts that are edited and expressed throughout development. Despite a neural-specific down-regulation of adr-2 during development, the majority of these sites show increased editing in adult neural cells. Biochemical data suggest that ADR-1, a deaminase-deficient member of the adenosine deaminase acting on RNA (ADAR) family, is competing with ADR-2 for binding to specific transcripts early in development. Our data suggest a model in which during neural development, ADR-2 levels overcome ADR-1 repression, resulting in increased ADR-2 binding and editing of specific transcripts. Together, our findings reveal tissue- and development-specific regulation of RNA editing and identify a molecular mechanism that regulates ADAR substrate recognition and editing efficiency.