Derek A Persons

St. Jude Children's Research Hospital, Memphis, Tennessee, United States

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Publications (77)613.71 Total impact

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    ABSTRACT: Foamy virus (FV) vectors are promising tools for gene therapy, but low titer is a major challenge for large-scale clinical trials. Here, we increased FV vector titer 50-fold by constructing novel vector plasmids and using polyethylenimine-mediated transfection. FV and lentiviral (LV) vectors were used separately to transduce human CD34+ cells at multiplicities of infection of 25, and those cells were transplanted into immunodeficient mice. FV vector transduction frequencies of repopulating human cells were 37.1±1.9% in unstimulated cells and 36.9±2.2% in pre-stimulated cells, and engraftment frequencies were 40.9±4.9% in unstimulated cells and 47.1±3.3% in pre-stimulated cells. Engraftment frequencies of FV vector-transduced cells were significantly higher than those of LV vector-transduced cells. Linear amplification-mediated PCR with Illumina paired-end runs showed that all human chromosomes contained FV provirus. FV had integration preference near transcriptional start sites and CpG islands of RefSeq genes but not within genes. Repopulating lymphoid and myeloid cells contained common integration sites, suggesting that FV vector could transduce multi-lineage hematopoietic stem/progenitor populations. Our new FV vector backbone may be a suitable candidate for developing therapeutic FV vectors for use in clinical trials.
    Molecular Therapy - Methods & Clinical Development. 06/2014;
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    ABSTRACT: Sickle cell disease (SCD) patients are at high risk of contracting pneumococcal infection. To address this risk, they receive pneumococcal vaccines, and antibiotic prophylaxis and treatment. To assess the impact of SCD and these interventions on pneumococcal genetic architecture, we examined the genomes of more than 300 pneumococcal isolates from SCD patients over 20 years. Modern SCD strains retained invasive capacity but shifted away from the serotypes used in vaccines. These strains had specific genetic changes related to antibiotic resistance, capsule biosynthesis, metabolism, and metal transport. A murine SCD model coupled with Tn-seq mutagenesis identified 60 noncapsular pneumococcal genes under differential selective pressure in SCD, which correlated with aspects of SCD pathophysiology. Further, virulence determinants in the SCD context were distinct from the general population, and protective capacity of potential antigens was lost over time in SCD. This highlights the importance of understanding bacterial pathogenesis in the context of high-risk individuals.
    Cell host & microbe 05/2014; 15(5):587-99. · 13.02 Impact Factor
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    ABSTRACT: Hematopoietic stem cells are both necessary and sufficient to sustain the complete blood system of vertebrates. Here we show that Nfix, a member of the nuclear factor I (Nfi) family of transcription factors, is highly expressed by hematopoietic stem and progenitor cells (HSPC) of murine adult bone marrow. Although shRNA mediated knockdown of Nfix expression in Lineage-Sca-1+c-Kit+ HSPC had no effect on in vitro cell growth or viability, Nfix-depleted HSPC displayed a significant loss of colony forming potential, as well as short- and long-term in vivo hematopoietic repopulating activity. Analysis of recipient mice 4-20 days post-transplant revealed that Nfix-depleted HSPC establish in the bone marrow but fail to persist due to increased apoptotic cell death. Gene expression profiling of Nfix-depleted HSPC reveals that loss of Nfix expression in HSPC is concomitant with a decrease in the expression of multiple genes known to be important for HSPC survival, such as Erg, Mecom and Mpl. These data reveal that Nfix is a novel regulator of HSPC survival post-transplantation and establish a role for Nfi genes in the regulation of this cellular compartment.
    Blood 09/2013; · 9.78 Impact Factor
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    ABSTRACT: The safety of lentiviral (LV) vectors for gene therapy of genetic hematopoietic diseases would be considerably enhanced by the identification of a non-viral promoter capable of driving therapeutic levels of transgene expression in the target cell. Here, we tested the efficacy of the murine phosphoglycerate kinase (mPgk) promoter in a self-inactivating (SIN) LV vector to express canine CD18 in animals with canine leukocyte adhesion deficiency (CLAD) and in human LAD-1 CD34+ cells in NSG mice. Despite high transduction levels and high levels of CD18 expression per cell in CLAD CD34+ cells in vitro using the mPgk vector to drive canine CD18 expression, only two of five CLAD animals treated with ex vivo gene therapy achieved therapeutic levels of CD18+ neutrophils in vivo. Similarly, despite high transduction efficiency and high levels of CD18 expression in human LAD-1 CD34+ cells in vitro, the mPgk-hCD18 promoter resulted in a low percentage of CD45+/CD18+ cells and low levels of CD18 expression per neutrophil, when the transduced cells were transplanted into NSG mice. In contrast, human LAD-1 CD34+ cells transduced with a LV vector containing the viral MND promoter (MND-hCD18) and injected into NSG mice displayed a high percentage of CD45+/CD18+ cells and high levels of CD18 expression per neutrophil. These studies demonstrated that the mPgk promoter does not direct sufficient CD18 expression in neutrophils to replace a viral promoter for gene therapy of children with LAD-1.
    Gene Therapy and Regulation 02/2013; 07(01).
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    ABSTRACT: Human immunodeficiency virus type 1 (HIV1) vectors poorly transduce rhesus hematopoietic cells due to species-specific restriction factors, including the tripartite motif-containing 5 isoformα (TRIM5α) which targets the HIV1 capsid. We previously developed a chimeric HIV1 (χHIV) vector system wherein the vector genome is packaged with the simian immunodeficiency virus (SIV) capsid for efficient transduction of both rhesus and human CD34(+) cells. To evaluate whether χHIV vectors could efficiently transduce rhesus hematopoietic repopulating cells, we performed a competitive repopulation assay in rhesus macaques, in which half of the CD34(+) cells were transduced with standard SIV vectors and the other half with χHIV vectors. As compared with SIV vectors, χHIV vectors achieved higher vector integration, and the transgene expression rates were two- to threefold higher in granulocytes and red blood cells and equivalent in lymphocytes and platelets for 2 years. A recipient of χHIV vector-only transduced cells reached up to 40% of transgene expression rates in granulocytes and lymphocytes and 20% in red blood cells. Similar to HIV1 and SIV vectors, χHIV vector frequently integrated into gene regions, especially into introns. In summary, our χHIV vector demonstrated efficient transduction for rhesus long-term repopulating cells, comparable with SIV vectors. This χHIV vector should allow preclinical testing of HIV1-based therapeutic vectors in large animal models.
    Molecular Therapy 08/2012; 20(10):1882-92. · 7.04 Impact Factor
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    Md Nasimuzzaman, Derek A Persons
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    ABSTRACT: Foamy viruses (FVs) (spumaretroviruses) are good alternative to retroviruses as gene therapy vector. Despite four decades since the discovery of FV, its receptor molecule is still unknown. FV vector transduction of human CD34(+) cells was inhibited by culture with fibronectin. Because fibronectin contains heparin-binding domain, the interactions of fibronectin with heparan sulfate (HS) on cells might be inhibitory to FV transduction. These observations led us to investigate whether HS is a receptor for FV. Two mutant CHO cell lines (but not parental wild type) lacking cell surface HS but not chondroitin sulfate (CS) were largely resistant to FV attachment and transduction. Inhibition of HS expression using enzymes or chemicals greatly reduced FV transduction in human, monkey, and rodent cells. Raji cells, which lack HS and were largely resistant to FV, were rendered more permissive through ectopic expression of syndecan-1, which contains HS. In contrast, mutant syndecan-1-expressing cells were largely resistant to FV. Our findings indicate that cellular HS is a receptor for FV. Identifying FV receptor will enable better understanding of its entry process and optimal use as gene therapy vector to treat inherited and pathogenic diseases.
    Molecular Therapy 03/2012; 20(6):1158-66. · 7.04 Impact Factor
  • Arthur W Nienhuis, Derek A Persons
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    ABSTRACT: Retroviral vector-mediated gene transfer into hematopoietic stem cells provides a potentially curative therapy for severe β-thalassemia. Lentiviral vectors based on human immunodeficiency virus have been developed for this purpose and have been shown to be effective in curing thalassemia in mouse models. One participant in an ongoing clinical trial has achieved transfusion independence after gene transfer into bone marrow stem cells owing, in part, to a genetically modified, dominant clone. Ongoing efforts are focused on improving the efficiency of lentiviral vector-mediated gene transfer into stem cells so that the curative potential of gene transfer can be consistently achieved.
    Cold Spring Harbor Perspectives in Medicine 01/2012; 2(11). · 7.56 Impact Factor
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    ABSTRACT: Sickle cell anemia is characterized by chronic hemolysis coupled with extensive vascular inflammation. This inflammatory state also mechanistically promotes a high risk of lethal, invasive pneumococcal infection. Current treatments to reduce vaso-occlusive complications include chronic hydroxyurea therapy to induce fetal hemoglobin. Because hydroxyurea also reduces leukocytosis, an understanding of the impact of this treatment on pneumococcal pathogenesis is needed. Using a sickle cell mouse model of pneumococcal pneumonia and sepsis, administration of hydroxyurea was found to significantly improve survival. Hydroxyurea treatment decreased neutrophil extravasation into the infected lung coincident with significantly reduced levels of E-selectin in serum and on pulmonary epithelia. The protective effect of hydroxyurea was abrogated in mice deficient in E-selectin. The decrease in E-selectin levels was also evident in human sickle cell patients receiving hydroxyurea therapy. These data indicate that in addition to induction of fetal hemoglobin, hydroxyurea attenuates leukocyte-endothelial interactions in sickle cell anemia, resulting in protection against lethal pneumococcal sepsis.
    Blood 11/2011; 119(8):1915-21. · 9.78 Impact Factor
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    ABSTRACT: FOXP3 is critical for the development and function of CD4(+)CD25(bright) natural regulatory T cells (nTreg). Individuals harboring mutations in FOXP3 develop immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome (IPEX). We describe a child diagnosed with IPEX who underwent a reduced intensity, T and B cell depleted, matched unrelated donor bone marrow transplant followed by clinical resolution. Using lineage-specific donor chimerism studies, we demonstrate that non-myeloablative HSCT resolves disease in the context of low level donor hematopoietic stem cell (HSC) engraftment. Despite low-levels of donor HSC, thymically-derived nTreg and to a lesser extent CD4(+) and CD8(+) T cells, exhibit a selective in vivo growth advantage for populations containing a functional FOXP3 gene. Moreover, nTreg from this patient show regulatory function directly ex vivo. These results have implications for improving clinical therapy for patients with IPEX and provide mechanistic insight into the in vivo development of human nTreg and unexpectedly, non-regulatory T cells.
    Clinical Immunology 08/2011; 141(2):169-76. · 3.77 Impact Factor
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    Andrew Wilber, Arthur W Nienhuis, Derek A Persons
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    ABSTRACT: In humans, embryonic, fetal, and adult hemoglobins are sequentially expressed in developing erythroblasts during ontogeny. For the past 40 years, this process has been the subject of intensive study because of its value to enlighten the biology of developmental gene regulation and because fetal hemoglobin can significantly ameliorate the clinical manifestations of both sickle cell disease and β-thalassemia. Understanding the normal process of loss of fetal globin expression and activation of adult globin expression could potentially lead to new therapeutic approaches for these hemoglobin disorders. Herein, we briefly review the history of the study of hemoglobin switching and then focus on recent discoveries in the field that now make new therapeutic approaches seem feasible in the future. Erythroid-specific knockdown of fetal gene repressors or enforced expression of fetal gene activators may provide clinically applicable approaches for genetic treatment of hemoglobin disorders that would benefit from increased fetal hemoglobin levels.
    Blood 02/2011; 117(15):3945-53. · 9.78 Impact Factor
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    Derek A Persons, Christopher Baum
    Molecular Therapy 02/2011; 19(2):229-31. · 7.04 Impact Factor
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    ABSTRACT: Children with leukocyte adhesion deficiency type 1 (LAD-1) and dogs with canine LAD (CLAD) develop life-threatening bacterial infections due to mutations in the leukocyte integrin CD18. Here, we compared the human phosphoglycerate kinase (hPGK) promoter to the murine stem cell virus (MSCV) promoter/enhancer in a self-inactivating HIV-1-derived lentiviral vector to treat animals with CLAD. Four CLAD dogs were infused with CD34(+) cells transduced with the hPGK vector, and two CLAD dogs received MSCV vector-transduced CD34(+) cells. Infusions were preceded by a nonmyeloablative dose of 200 cGy total body irradiation. Comparable numbers of transduced cells were infused in each group of animals. Only one of four CLAD animals treated with the hPGK-cCD18 vector had reversal of CLAD, whereas both MSCV-cCD18 vector-treated dogs had reversal of the phenotype. Correction of CLAD depends both upon the percentage of CD18(+) myeloid cells and the level of expression of CD18 on individual myeloid cells. In this regard, the hPGK promoter directed low levels of expression of CD18 on neutrophils compared to the MSCV promoter, likely contributing to the suboptimal clinical outcome with the hPGK vector.
    Human gene therapy 01/2011; 22(6):689-96. · 4.20 Impact Factor
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    ABSTRACT: β-Thalassemia major results from severely reduced or absent expression of the β-chain of adult hemoglobin (α₂β₂;HbA). Increased levels of fetal hemoglobin (α₂γ₂;HbF), such as occurs with hereditary persistence of HbF, ameliorate the severity of β-thalassemia, raising the potential for genetic therapy directed at enhancing HbF. We used an in vitro model of human erythropoiesis to assay for enhanced production of HbF after gene delivery into CD34(+) cells obtained from mobilized peripheral blood of normal adults or steady-state bone marrow from patients with β-thalassemia major. Lentiviral vectors encoding (1) a human γ-globin gene with or without an insulator, (2) a synthetic zinc-finger transcription factor designed to interact with the γ-globin gene promoters, or (3) a short-hairpin RNA targeting the γ-globin gene repressor, BCL11A, were tested. Erythroid progeny of normal CD34(+) cells demonstrated levels of HbF up to 21% per vector copy. For β-thalassemic CD34(+) cells, similar gene transfer efficiencies achieved HbF production ranging from 45% to 60%, resulting in up to a 3-fold increase in the total cellular Hb content. These observations suggest that both lentiviral-mediated γ-globin gene addition and genetic reactivation of endogenous γ-globin genes have potential to provide therapeutic HbF levels to patients with β-globin deficiency.
    Blood. 01/2011; 117:2817-26.
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    ABSTRACT: β-Thalassemia major results from severely reduced or absent expression of the β-chain of adult hemoglobin (α₂β₂;HbA). Increased levels of fetal hemoglobin (α₂γ₂;HbF), such as occurs with hereditary persistence of HbF, ameliorate the severity of β-thalassemia, raising the potential for genetic therapy directed at enhancing HbF. We used an in vitro model of human erythropoiesis to assay for enhanced production of HbF after gene delivery into CD34(+) cells obtained from mobilized peripheral blood of normal adults or steady-state bone marrow from patients with β-thalassemia major. Lentiviral vectors encoding (1) a human γ-globin gene with or without an insulator, (2) a synthetic zinc-finger transcription factor designed to interact with the γ-globin gene promoters, or (3) a short-hairpin RNA targeting the γ-globin gene repressor, BCL11A, were tested. Erythroid progeny of normal CD34(+) cells demonstrated levels of HbF up to 21% per vector copy. For β-thalassemic CD34(+) cells, similar gene transfer efficiencies achieved HbF production ranging from 45% to 60%, resulting in up to a 3-fold increase in the total cellular Hb content. These observations suggest that both lentiviral-mediated γ-globin gene addition and genetic reactivation of endogenous γ-globin genes have potential to provide therapeutic HbF levels to patients with β-globin deficiency.
    Blood 12/2010; 117(10):2817-26. · 9.78 Impact Factor
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    ABSTRACT: Excess free alpha-globin is cytotoxic and contributes to the pathophysiology of b-thalassemia. Alpha hemoglobin stabilizing protein (AHSP) is a molecular chaperone that binds free alpha-globin to promote its folding and inhibit its ability to produce damaging reactive oxygen species. Reduced AHSP levels correlate with increased severity of b-thalassemia in some human cohorts, but causal mechanistic relationships are not established for these associations. We used transgenic and lentiviral gene transfer methods to investigate whether supraphysiologic AHSP levels could mitigate the severity of b-thalassemia intermedia by providing an increased sink for the excess pool of alpha-globin chains. We tested wild-type AHSP and two mutant versions with amino acid substitutions that confer 3- or 13-fold higher affinity for alpha-globin. Erythroid overexpression of these AHSP proteins up to 11-fold beyond endogenous levels had no major effects on hematologic parameters in b-thalassemic animals. Our results demonstrate that endogenous AHSP is not limiting for a-globin detoxification in a murine model of b-thalassemia.
    American Journal of Hematology 10/2010; 85(10):820-2. · 4.00 Impact Factor
  • Derek A Persons
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    ABSTRACT: Patients with disorders of the blood protein haemoglobin often depend on lifelong blood transfusions. That could change, given the success of gene therapy in a patient with one such disorder.
    Nature 09/2010; 467(7313):277-8. · 38.60 Impact Factor
  • Derek A Persons
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    ABSTRACT: Hematopoietic stem cells (HSCs) function to provide the individual with a continuing supply of blood cells over many decades. To this end, HSCs have evolved unique mechanisms for self-preservation, including resistance to viral infection. Unfortunately, this characteristic may impede the ability to achieve high levels of gene transfer mediated by HIV-based lentiviral vectors. This is an important consideration for gene therapy efforts being undertaken for beta-thalassemia. In particular, the study of beta-thalassemia patients that underwent allogeneic stem cell transplantation and developed stable, long-term mixed chimerism suggests that HSC gene transfer levels of greater than 25% will be needed for a robust therapeutic effect in such patients. Available pre-clinical and clinical trial lentiviral gene transfer studies suggest that improvements are needed to achieve this goal. Here, we review what level of gene transfer is needed in the context of varying degrees of beta-globin deficiency, what level is currently achievable, and the areas of research which may be fruitful in improving the likelihood of success for patients with the severest forms of beta-thalassemia.
    Annals of the New York Academy of Sciences 08/2010; 1202:69-74. · 4.38 Impact Factor
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    Derek A Persons
    Molecular Therapy 05/2010; 18(5):861-2. · 7.04 Impact Factor
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    ABSTRACT: Hydroxyurea has proven clinical efficacy in patients with sickle cell disease. Potential mechanisms for the beneficial effects include fetal hemoglobin induction and the reduction of cell adhesive properties, inflammation and hypercoagulability. Using a murine model of sickle cell disease in which fetal hemoglobin induction does not occur, we evaluated whether hydroxyurea administration would still yield improvements in hematologic parameters and reduce end-organ damage. Animals given a maximally tolerated dose of hydroxyurea that resulted in significant reductions in the neutrophil and platelet counts showed no improvement in hemolytic anemia and end-organ damage compared to control mice. In contrast, animals having high levels of fetal hemoglobin due to gene transfer with a gamma-globin lentiviral vector showed correction of anemia and organ damage. These data suggest that induction of fetal hemoglobin by hydroxyurea is an essential mechanism for its clinical benefits.
    Haematologica 04/2010; 95(9):1599-603. · 5.94 Impact Factor
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    ABSTRACT: Lentiviral vectors are useful for transducing primitive hematopoietic cells. We examined four envelope proteins for their ability to mediate lentiviral transduction of mobilized human CD34(+) peripheral blood cells. Lentiviral particles encoding green fluorescent protein (GFP) were pseudotyped with the vesicular stomatitis virus envelope glycoprotein (VSV-G), the amphotropic (AMPHO) murine leukemia virus envelope protein, the endogenous feline leukemia viral envelope protein or the feline leukemia virus type C envelope protein. Because the relative amount of genome RNA per ml was similar for each pseudotype, we transduced CD34(+) cells with a fixed volume of each vector preparation. Following an overnight transduction, CD34(+) cells were transplanted into immunodeficient mice which were sacrificed 12 weeks later. The average percentages of engrafted human CD45(+) cells in total bone marrow were comparable to that of the control, mock-transduced group (37-45%). Lenti-particles pseudotyped with the VSV-G envelope protein transduced engrafting cells two- to tenfold better than particles pseudotyped with any of the gamma-retroviral envelope proteins. There was no correlation between receptor mRNA levels for the gamma-retroviral vectors and transduction efficiency of primitive hematopoietic cells. These results support the use of the VSV-G envelope protein for the development of lentiviral producer cell lines for manufacture of clinical-grade vector.
    Molecular Therapy 04/2010; 18(7):1310-7. · 7.04 Impact Factor

Publication Stats

3k Citations
613.71 Total Impact Points

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Institutions

  • 1997–2014
    • St. Jude Children's Research Hospital
      • • Division of Experimental Hematology
      • • Department of Hematology
      Memphis, Tennessee, United States
  • 2010–2011
    • Southern Illinois University School of Medicine
      • Department of Surgery
      Springfield, IL, United States
  • 2009
    • National Heart, Lung, and Blood Institute
      • Hematology Branch
      Bethesda, MD, United States
    • Nippon Medical School
      • Department of Biochemistry and Molecular Biology
      Tokyo, Tokyo-to, Japan