RESUMEN
Distal enhancers commonly contact target promoters via chromatin looping. In erythroid cells, the locus control region (LCR) contacts ß-type globin genes in a developmental stage-specific manner to stimulate transcription. Previously, we induced LCR-promoter looping by tethering the self-association domain (SA) of Ldb1 to the ß-globin promoter via artificial zinc fingers. Here, we show that targeting the SA to a developmentally silenced embryonic globin gene in adult murine erythroblasts triggers its transcriptional reactivation. This activity depends on the LCR, consistent with an LCR-promoter looping mechanism. Strikingly, targeting the SA to the fetal γ-globin promoter in primary adult human erythroblasts increases γ-globin promoter-LCR contacts, stimulating transcription to approximately 85% of total ß-globin synthesis, with a reciprocal reduction in adult ß-globin expression. Our findings demonstrate that forced chromatin looping can override a stringent developmental gene expression program and suggest a novel approach to control the balance of globin gene transcription for therapeutic applications.
Asunto(s)
Cromatina/metabolismo , Hemoglobina Fetal/genética , Técnicas Genéticas , Región de Control de Posición , Activación Transcripcional , Globinas beta/genética , Animales , Antígenos CD34/metabolismo , Cromatina/química , Embrión de Mamíferos/metabolismo , Eritroblastos/metabolismo , Hemoglobinopatías/genética , Hemoglobinopatías/terapia , Humanos , Ratones , Cultivo Primario de CélulasRESUMEN
Chromatin loops juxtapose distal enhancers with active promoters, but their molecular architecture and relationship with transcription remain unclear. In erythroid cells, the locus control region (LCR) and ß-globin promoter form a chromatin loop that requires transcription factor GATA1 and the associated molecule Ldb1. We employed artificial zinc fingers (ZF) to tether Ldb1 to the ß-globin promoter in GATA1 null erythroblasts, in which the ß-globin locus is relaxed and inactive. Remarkably, targeting Ldb1 or only its self-association domain to the ß-globin promoter substantially activated ß-globin transcription in the absence of GATA1. Promoter-tethered Ldb1 interacted with endogenous Ldb1 complexes at the LCR to form a chromatin loop, causing recruitment and phosphorylation of RNA polymerase II. ZF-Ldb1 proteins were inactive at alleles lacking the LCR, demonstrating that their activities depend on long-range interactions. Our findings establish Ldb1 as a critical effector of GATA1-mediated loop formation and indicate that chromatin looping causally underlies gene regulation.
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Cromatina/metabolismo , Proteínas de Unión al ADN/metabolismo , Proteínas con Dominio LIM/metabolismo , Transcripción Genética , Globinas beta/genética , Animales , Línea Celular , Separación Celular , Proteínas de Unión al ADN/química , Embrión de Mamíferos/citología , Eritroblastos/metabolismo , Femenino , Factor de Transcripción GATA1/metabolismo , Regulación de la Expresión Génica , Proteínas con Dominio LIM/química , Masculino , Ratones , Regiones Promotoras Genéticas , Estructura Terciaria de Proteína , Dedos de ZincRESUMEN
Autologous transplantation and engraftment of HIV-resistant cells in sufficient numbers should recapitulate the functional cure of the Berlin Patient, with applicability to a greater number of infected individuals and with a superior safety profile. A robust preclinical model of suppressed HIV infection is critical in order to test such gene therapy-based cure strategies, both alone and in combination with other cure strategies. Here, we present a nonhuman primate (NHP) model of latent infection using simian/human immunodeficiency virus (SHIV) and combination antiretroviral therapy (cART) in pigtail macaques. We demonstrate that transplantation of CCR5 gene-edited hematopoietic stem/progenitor cells (HSPCs) persist in infected and suppressed animals, and that protected cells expand through virus-dependent positive selection. CCR5 gene-edited cells are readily detectable in tissues, namely those closely associated with viral reservoirs such as lymph nodes and gastrointestinal tract. Following autologous transplantation, tissue-associated SHIV DNA and RNA levels in suppressed animals are significantly reduced (p ≤ 0.05), relative to suppressed, untransplanted control animals. In contrast, the size of the peripheral reservoir, measured by QVOA, is variably impacted by transplantation. Our studies demonstrate that CCR5 gene editing is equally feasible in infected and uninfected animals, that edited cells persist, traffic to, and engraft in tissue reservoirs, and that this approach significantly reduces secondary lymphoid tissue viral reservoir size. Our robust NHP model of HIV gene therapy and viral persistence can be immediately applied to the investigation of combinatorial approaches that incorporate anti-HIV gene therapy, immune modulators, therapeutic vaccination, and latency reversing agents.
Asunto(s)
Terapia Genética , Trasplante de Células Madre Hematopoyéticas , Receptores CCR5/genética , Síndrome de Inmunodeficiencia Adquirida del Simio/terapia , Virus de la Inmunodeficiencia de los Simios/fisiología , Carga Viral/fisiología , Animales , Antirretrovirales/uso terapéutico , Células Madre Hematopoyéticas/citología , Células Madre Hematopoyéticas/metabolismo , Macaca nemestrina , Masculino , Síndrome de Inmunodeficiencia Adquirida del Simio/genética , Síndrome de Inmunodeficiencia Adquirida del Simio/virología , Trasplante Autólogo , Latencia del Virus , Replicación ViralRESUMEN
Transfer of T-cell receptors (TCRs) specific for tumor-associated antigens is a promising approach for cancer immunotherapy. We developed the TCR gene editing technology that is based on the knockout of the endogenous TCR α and ß genes, followed by the introduction of tumor-specific TCR genes, and that proved safer and more effective than conventional TCR gene transfer. Although successful, complete editing requires extensive cell manipulation and 4 transduction procedures. Here we propose a novel and clinically feasible TCR "single editing" (SE) approach, based on the disruption of the endogenous TCR α chain only, followed by the transfer of genes encoding for a tumor-specific TCR. We validated SE with the clinical grade HLA-A2 restricted NY-ESO-1157-165-specific TCR. SE allowed the rapid production of high numbers of tumor-specific T cells, with optimal TCR expression and preferential stem memory and central memory phenotype. Similarly to unedited T cells redirected by TCR gene transfer (TCR transferred [TR]), SE T cells efficiently killed NY-ESO-1pos targets; however, although TR cells proved highly alloreactive, SE cells showed a favorable safety profile. Accordingly, when infused in NSG mice previously engrafted with myeloma, SE cells mediated tumor rejection without inducing xenogeneic graft-versus-host disease, thus resulting in significantly higher survival than that observed in mice treated with TR cells. Overall, single TCR gene editing represents a clinically feasible approach that is able to increase the safety and efficacy of cancer adoptive immunotherapy.
Asunto(s)
Traslado Adoptivo , Edición Génica/métodos , Memoria Inmunológica , Mieloma Múltiple , Proteínas de Neoplasias , Fragmentos de Péptidos , Receptores de Antígenos de Linfocitos T , Linfocitos T , Animales , Línea Celular Tumoral , Femenino , Técnicas de Transferencia de Gen , Enfermedad Injerto contra Huésped , Ratones , Mieloma Múltiple/genética , Mieloma Múltiple/inmunología , Mieloma Múltiple/terapia , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/inmunología , Fragmentos de Péptidos/genética , Fragmentos de Péptidos/inmunología , Receptores de Antígenos de Linfocitos T/genética , Receptores de Antígenos de Linfocitos T/inmunología , Linfocitos T/inmunología , Linfocitos T/trasplante , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Regulatory regions harbor multiple transcription factor (TF) recognition sites; however, the contribution of individual sites to regulatory function remains challenging to define. We describe an approach that exploits the error-prone nature of genome editing-induced double-strand break repair to map functional elements within regulatory DNA at nucleotide resolution. We demonstrate the approach on a human erythroid enhancer, revealing single TF recognition sites that gate the majority of downstream regulatory function.
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Proteínas Portadoras/genética , Huella de ADN/métodos , Genómica/métodos , Proteínas Nucleares/genética , Secuencias Reguladoras de Ácidos Nucleicos , Secuencia de Bases , Sitios de Unión , Roturas del ADN de Doble Cadena , Reparación del ADN , Elementos de Facilitación Genéticos , Eritrocitos/fisiología , Eritropoyesis , Genoma Humano , Humanos , Mutación , Proteínas Represoras , Factores de Transcripción/metabolismoRESUMEN
Sickle cell disease (SCD) is characterized by a single point mutation in the seventh codon of the ß-globin gene. Site-specific correction of the sickle mutation in hematopoietic stem cells would allow for permanent production of normal red blood cells. Using zinc-finger nucleases (ZFNs) designed to flank the sickle mutation, we demonstrate efficient targeted cleavage at the ß-globin locus with minimal off-target modification. By co-delivering a homologous donor template (either an integrase-defective lentiviral vector or a DNA oligonucleotide), high levels of gene modification were achieved in CD34(+) hematopoietic stem and progenitor cells. Modified cells maintained their ability to engraft NOD/SCID/IL2rγ(null) mice and to produce cells from multiple lineages, although with a reduction in the modification levels relative to the in vitro samples. Importantly, ZFN-driven gene correction in CD34(+) cells from the bone marrow of patients with SCD resulted in the production of wild-type hemoglobin tetramers.
Asunto(s)
Anemia de Células Falciformes/genética , Anemia de Células Falciformes/terapia , Terapia Genética , Células Madre Hematopoyéticas/metabolismo , Mutación , Globinas beta/genética , Anemia de Células Falciformes/patología , Animales , Antígenos CD34/análisis , Secuencia de Bases , Células de la Médula Ósea/metabolismo , Células de la Médula Ósea/patología , Células Cultivadas , Endodesoxirribonucleasas/metabolismo , Sangre Fetal/trasplante , Sitios Genéticos , Trasplante de Células Madre Hematopoyéticas , Células Madre Hematopoyéticas/patología , Humanos , Ratones , Ratones Endogámicos NOD , Ratones SCID , Datos de Secuencia Molecular , Dedos de ZincRESUMEN
Programmed cell death-1 (PD-1) is expressed on activated T cells and represents an attractive target for gene-editing of tumor targeted T cells prior to adoptive cell transfer (ACT). We used zinc finger nucleases (ZFNs) directed against the gene encoding human PD-1 (PDCD-1) to gene-edit melanoma tumor infiltrating lymphocytes (TIL). We show that our clinical scale TIL production process yielded efficient modification of the PD-1 gene locus, with an average modification frequency of 74.8% (n = 3, range 69.9-84.1%) of the alleles in a bulk TIL population, which resulted in a 76% reduction in PD-1 surface-expression. Forty to 48% of PD-1 gene-edited cells had biallelic PD-1 modification. Importantly, the PD-1 gene-edited TIL product showed improved in vitro effector function and a significantly increased polyfunctional cytokine profile (TNFα, GM-CSF, and IFNγ) compared to unmodified TIL in two of the three donors tested. In addition, all donor cells displayed an effector memory phenotype and expanded approximately 500-2,000-fold in vitro. Thus, further study to determine the efficiency and safety of adoptive cell transfer using PD-1 gene-edited TIL for the treatment of metastatic melanoma is warranted.
Asunto(s)
Endorribonucleasas/genética , Regulación Neoplásica de la Expresión Génica , Linfocitos Infiltrantes de Tumor/inmunología , Melanoma/terapia , Receptor de Muerte Celular Programada 1/genética , Dedos de Zinc , Alelos , Animales , Separación Celular , Citocinas/metabolismo , Femenino , Citometría de Flujo , Factor Estimulante de Colonias de Granulocitos y Macrófagos/metabolismo , Proteínas Fluorescentes Verdes/metabolismo , Humanos , Memoria Inmunológica , Inmunoterapia Adoptiva , Interferón gamma/metabolismo , Activación de Linfocitos/inmunología , Ratones , Metástasis de la Neoplasia , Trasplante de Neoplasias , Fenotipo , Receptor de Muerte Celular Programada 1/metabolismo , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
Long-term engraftment of allogeneic cells necessitates eluding immune-mediated rejection, which is currently achieved by matching for human leukocyte antigen (HLA) expression, immunosuppression, and/or delivery of donor-derived cells to sanctuary sites. Genetic engineering provides an alternative approach to avoid clearance of cells that are recognized as "non-self" by the recipient. To this end, we developed designer zinc finger nucleases and employed a "hit-and-run" approach to genetic editing for selective elimination of HLA expression. Electro-transfer of mRNA species coding for these engineered nucleases completely disrupted expression of HLA-A on human T cells, including CD19-specific T cells. The HLA-A(neg) T-cell pools can be enriched and evade lysis by HLA-restricted cytotoxic T-cell clones. Recognition by natural killer cells of cells that had lost HLA expression was circumvented by enforced expression of nonclassical HLA molecules. Furthermore, we demonstrate that zinc finger nucleases can eliminate HLA-A expression from embryonic stem cells, which broadens the applicability of this strategy beyond infusing HLA-disparate immune cells. These findings establish that clinically appealing cell types derived from donors with disparate HLA expression can be genetically edited to evade an immune response and provide a foundation whereby cells from a single donor can be administered to multiple recipients.
Asunto(s)
Desoxirribonucleasas/genética , Antígenos de Histocompatibilidad Clase I/metabolismo , Trasplante de Células Madre/métodos , Trasplante Homólogo , Antígenos CD19/metabolismo , Secuencia de Bases , Diferenciación Celular , Citotoxicidad Inmunológica/inmunología , Electroporación , Células Madre Embrionarias/citología , Técnicas de Transferencia de Gen , Células HEK293 , Humanos , Leucocitos Mononucleares/citología , Datos de Secuencia Molecular , Ingeniería de Proteínas , Linfocitos T/inmunología , Dedos de ZincRESUMEN
Clinical-grade T cells are genetically modified ex vivo to express a chimeric antigen receptor (CAR) to redirect specificity to a tumor associated antigen (TAA) thereby conferring antitumor activity in vivo. T cells expressing a CD19-specific CAR recognize B-cell malignancies in multiple recipients independent of major histocompatibility complex (MHC) because the specificity domains are cloned from the variable chains of a CD19 monoclonal antibody. We now report a major step toward eliminating the need to generate patient-specific T cells by generating universal allogeneic TAA-specific T cells from one donor that might be administered to multiple recipients. This was achieved by genetically editing CD19-specific CAR(+) T cells to eliminate expression of the endogenous αß T-cell receptor (TCR) to prevent a graft-versus-host response without compromising CAR-dependent effector functions. Genetically modified T cells were generated using the Sleeping Beauty system to stably introduce the CD19-specific CAR with subsequent permanent deletion of α or ß TCR chains with designer zinc finger nucleases. We show that these engineered T cells display the expected property of having redirected specificity for CD19 without responding to TCR stimulation. CAR(+)TCR(neg) T cells of this type may potentially have efficacy as an off-the-shelf therapy for investigational treatment of B-lineage malignancies.
Asunto(s)
Antígenos CD19/inmunología , Epítopos/inmunología , Ingeniería Genética , Inmunoterapia/métodos , Receptores de Antígenos de Linfocitos T/inmunología , Proteínas Recombinantes/inmunología , Linfocitos T/inmunología , Adulto , Células Presentadoras de Antígenos/inmunología , Antígenos de Neoplasias/inmunología , Antígenos CD28/metabolismo , Complejo CD3/metabolismo , Células Cultivadas , Endonucleasas/metabolismo , Técnicas de Inactivación de Genes , Humanos , Células K562 , Activación de Linfocitos/inmunología , Dedos de ZincRESUMEN
Nucleobase editors represent an emerging technology that enables precise single-base edits to the genomes of eukaryotic cells. Most nucleobase editors use deaminase domains that act upon single-stranded DNA and require RNA-guided proteins such as Cas9 to unwind the DNA prior to editing. However, the most recent class of base editors utilizes a deaminase domain, DddAtox, that can act upon double-stranded DNA. Here, we target DddAtox fragments and a FokI-based nickase to the human CIITA gene by fusing these domains to arrays of engineered zinc fingers (ZFs). We also identify a broad variety of Toxin-Derived Deaminases (TDDs) orthologous to DddAtox that allow us to fine-tune properties such as targeting density and specificity. TDD-derived ZF base editors enable up to 73% base editing in T cells with good cell viability and favorable specificity.
Asunto(s)
Citidina Desaminasa , Edición Génica , Humanos , Citidina Desaminasa/genética , Citidina Desaminasa/metabolismo , ADN/metabolismo , Dedos de Zinc , Citidina/genética , Sistemas CRISPR-CasRESUMEN
Gene silencing without gene editing holds great potential for the development of safe therapeutic applications. Here, we describe a novel strategy to concomitantly repress multiple genes using zinc finger proteins fused to Krüppel-Associated Box repression domains (ZF-Rs). This was achieved via the optimization of a lentiviral system tailored for the delivery of ZF-Rs in hematopoietic cells. We showed that an optimal design of the lentiviral backbone is crucial to multiplex up to three ZF-Rs or two ZF-Rs and a chimeric antigen receptor. ZF-R expression had no impact on the integrity and functionality of transduced cells. Furthermore, gene repression in ZF-R-expressing T cells was highly efficient in vitro and in vivo during the entire monitoring period (up to 10 weeks), and it was accompanied by epigenetic remodeling events. Finally, we described an approach to improve ZF-R specificity to illustrate the path toward the generation of ZF-Rs with a safe clinical profile. In conclusion, we successfully developed an epigenetic-based cell engineering approach for concomitant modulation of multiple gene expressions that bypass the risks associated with DNA editing.
RESUMEN
BACKGROUND: Wide-spread application of chimeric antigen receptor (CAR) T cell therapy for cancer is limited by the current use of autologous CAR T cells necessitating the manufacture of individualized therapeutic products for each patient. To address this challenge, we have generated an off-the-shelf, allogeneic CAR T cell product for the treatment of glioblastoma (GBM), and present here the feasibility, safety, and therapeutic potential of this approach. METHODS: We generated for clinical use a healthy-donor derived IL13Rα2-targeted CAR+ (IL13-zetakine+) cytolytic T-lymphocyte (CTL) product genetically engineered using zinc finger nucleases (ZFNs) to permanently disrupt the glucocorticoid receptor (GR) (GRm13Z40-2) and endow resistance to glucocorticoid treatment. In a phase I safety and feasibility trial we evaluated these allogeneic GRm13Z40-2 T cells in combination with intracranial administration of recombinant human IL-2 (rhIL-2; aldesleukin) in six patients with unresectable recurrent GBM that were maintained on systemic dexamethasone (4-12 mg/day). RESULTS: The GRm13Z40-2 product displayed dexamethasone-resistant effector activity without evidence for in vitro alloreactivity. Intracranial administration of GRm13Z40-2 in four doses of 108 cells over a two-week period with aldesleukin (9 infusions ranging from 2500-5000 IU) was well tolerated, with indications of transient tumor reduction and/or tumor necrosis at the site of T cell infusion in four of the six treated research subjects. Antibody reactivity against GRm13Z40-2 cells was detected in the serum of only one of the four tested subjects. CONCLUSIONS: This first-in-human experience establishes a foundation for future adoptive therapy studies using off-the-shelf, zinc-finger modified, and/or glucocorticoid resistant CAR T cells.
Asunto(s)
Glioblastoma , Subunidad alfa2 del Receptor de Interleucina-13 , Dexametasona , Glioblastoma/patología , Glucocorticoides , Humanos , Inmunoterapia Adoptiva , Esteroides , Linfocitos T , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Mammalian cells with multi-gene knockouts could be of considerable utility in research, drug discovery, and cell-based therapeutics. However, existing methods for targeted gene deletion require sequential rounds of homologous recombination and drug selection to isolate rare desired events--a process sufficiently laborious to limit application to individual loci. Here we present a solution to this problem. Firstly, we report the development of zinc-finger nucleases (ZFNs) targeted to cleave three independent genes with known null phenotypes. Mammalian cells exposed to each ZFN pair in turn resulted in the generation of cell lines harboring single, double, and triple gene knockouts, that is, the successful disruption of two, four, and six alleles. All three biallelic knockout events were obtained at frequencies of >1% without the use of selection, displayed the expected knockout phenotype(s), and harbored DNA mutations centered at the ZFN binding sites. These data demonstrate the utility of ZFNs in multi-locus genome engineering.
Asunto(s)
Desoxirribonucleasas/genética , Desoxirribonucleasas/metabolismo , Técnicas de Inactivación de Genes/métodos , Dedos de Zinc , Animales , Células CHO , Cricetinae , CricetulusRESUMEN
Engineered nucleases have gained broad appeal for their ability to mediate highly efficient genome editing. However the specificity of these reagents remains a concern, especially for therapeutic applications, given the potential mutagenic consequences of off-target cleavage. Here we have developed an approach for improving the specificity of zinc finger nucleases (ZFNs) that engineers the FokI catalytic domain with the aim of slowing cleavage, which should selectively reduce activity at low-affinity off-target sites. For three ZFN pairs, we engineered single-residue substitutions in the FokI domain that preserved full on-target activity but showed a reduction in off-target indels of up to 3,000-fold. By combining this approach with substitutions that reduced the affinity of zinc fingers, we developed ZFNs specific for the TRAC locus that mediated 98% knockout in T cells with no detectable off-target activity at an assay background of ~0.01%. We anticipate that this approach, and the FokI variants we report, will enable routine generation of nucleases for gene editing with no detectable off-target activity.
Asunto(s)
División del ADN , Edición Génica/métodos , Linfocitos T , Secuencia de Bases , ADN/genética , ADN/metabolismo , Citometría de Flujo , Células Madre Hematopoyéticas , Humanos , Células K562 , Dominios Proteicos , ARN MensajeroRESUMEN
As alterations in gene expression underlie a considerable proportion of human diseases, correcting such aberrant transcription in vivo is expected to provide therapeutic benefit to the patient. Attempts to control endogenous mammalian genes, however, face a significant obstacle in the form of chromatin. Aberrant gene repression can be alleviated by using small-molecule inhibitors that exert nucleus-wide effects on chromatin-based repressors. Genome-wide chromatin remodeling also occurs during cloning via nuclear transfer, and causes the deregulation of epigenetically controlled genes. Regulation of genes in vivo can be accomplished via the use of designed transcription factors - these result from a fusion of a designed DNA-binding domain based on the zinc finger protein motif to a functional domain of choice.
Asunto(s)
Cromatina/fisiología , Silenciador del Gen/fisiología , Animales , Cromatina/genética , Clonación de Organismos , Regulación de la Expresión Génica/fisiología , Silenciador del Gen/efectos de los fármacos , Globinas/genética , Globinas/fisiología , Inhibidores de Histona Desacetilasas , Histona Desacetilasas/fisiología , Humanos , Factores de Transcripción/fisiología , Transgenes/fisiologíaRESUMEN
In the present report, we carried out clinical-scale editing in adult mobilized CD34+ hematopoietic stem and progenitor cells (HSPCs) using zinc-finger nuclease-mediated disruption of BCL11a to upregulate the expression of γ-globin (fetal hemoglobin). In these cells, disruption of the erythroid-specific enhancer of the BCL11A gene increased endogenous γ-globin expression to levels that reached or exceeded those observed following knockout of the BCL11A coding region without negatively affecting survival or in vivo long-term proliferation of edited HSPCs and other lineages. In addition, BCL11A enhancer modification in mobilized CD34+ cells from patients with ß-thalassemia major resulted in a readily detectable γ-globin increase with a preferential increase in G-gamma, leading to an improved phenotype and, likely, a survival advantage for maturing erythroid cells after editing. Furthermore, we documented that both normal and ß-thalassemia HSPCs not only can be efficiently expanded ex vivo after editing but can also be successfully edited post-expansion, resulting in enhanced early in vivo engraftment compared with unexpanded cells. Overall, this work highlights a novel and effective treatment strategy for correcting the ß-thalassemia phenotype by genome editing.
RESUMEN
As a powerful regulator of cellular homeostasis and metabolism, adenosine is involved in diverse neurological processes including pain, cognition, and memory. Altered adenosine homeostasis has also been associated with several diseases such as depression, schizophrenia, or epilepsy. Based on its protective properties, adenosine has been considered as a potential therapeutic agent for various brain disorders. Since systemic application of adenosine is hampered by serious side effects such as vasodilatation and cardiac suppression, recent studies aim at improving local delivery by depots, pumps, or cell-based applications. Here, we report on the characterization of adenosine-releasing human embryonic stem cell-derived neuroepithelial stem cells (long-term self-renewing neuroepithelial stem [lt-NES] cells) generated by zinc finger nuclease (ZFN)-mediated knockout of the adenosine kinase (ADK) gene. ADK-deficient lt-NES cells and their differentiated neuronal and astroglial progeny exhibit substantially elevated release of adenosine compared to control cells. Importantly, extensive adenosine release could be triggered by excitation of differentiated neuronal cultures, suggesting a potential activity-dependent regulation of adenosine supply. Thus, ZFN-modified neural stem cells might serve as a useful vehicle for the activity-dependent local therapeutic delivery of adenosine into the central nervous system. Stem Cells Translational Medicine 2018;7:477-486.
Asunto(s)
Adenosina/metabolismo , Edición Génica/métodos , Células-Madre Neurales/metabolismo , Neuronas/metabolismo , Adenosina/análisis , Adenosina Quinasa/deficiencia , Adenosina Quinasa/genética , Animales , Línea Celular , Cromatografía Líquida de Alta Presión , Células Madre Embrionarias Humanas/citología , Humanos , Cariotipificación , Espectrometría de Masas , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Células-Madre Neurales/citología , Células-Madre Neurales/trasplante , Neuronas/citología , Polimorfismo de Nucleótido Simple , Nucleasas con Dedos de Zinc/genéticaRESUMEN
To develop an effective and sustainable cell therapy for sickle cell disease (SCD), we investigated the feasibility of targeted disruption of the BCL11A gene, either within exon 2 or at the GATAA motif in the intronic erythroid-specific enhancer, using zinc finger nucleases in human bone marrow (BM) CD34+ hematopoietic stem and progenitor cells (HSPCs). Both targeting strategies upregulated fetal globin expression in erythroid cells to levels predicted to inhibit hemoglobin S polymerization. However, complete inactivation of BCL11A resulting from bi-allelic frameshift mutations in BCL11A exon 2 adversely affected erythroid enucleation. In contrast, bi-allelic disruption of the GATAA motif in the erythroid enhancer of BCL11A did not negatively impact enucleation. Furthermore, BCL11A exon 2-edited BM-CD34+ cells demonstrated a significantly reduced engraftment potential in immunodeficient mice. Such an adverse effect on HSPC function was not observed upon BCL11A erythroid-enhancer GATAA motif editing, because enhancer-edited CD34+ cells achieved robust long-term engraftment and gave rise to erythroid cells with elevated levels of fetal globin expression when chimeric BM was cultured ex vivo. Altogether, our results support further clinical development of the BCL11A erythroid-specific enhancer editing in BM-CD34+ HSPCs as an autologous stem cell therapy in SCD patients.
RESUMEN
Mismatch of human leukocyte antigens (HLA) adversely impacts the outcome of patients after allogeneic hematopoietic stem-cell transplantation (alloHSCT). This translates into the clinical requirement to timely identify suitable HLA-matched donors which in turn curtails the chances of recipients, especially those from a racial minority, to successfully undergo alloHSCT. We thus sought to broaden the existing pool of registered unrelated donors based on analysis that eliminating the expression of the HLA-A increases the chance for finding a donor matched at HLA-B, -C, and -DRB1 regardless of a patient's race. Elimination of HLA-A expression in HSC was achieved using artificial zinc finger nucleases designed to target HLA-A alleles. Significantly, these engineered HSCs maintain their ability to engraft and reconstitute hematopoiesis in immunocompromised mice. This introduced loss of HLA-A expression decreases the need to recruit large number of donors to match with potential recipients and has particular importance for patients whose HLA repertoire is under-represented in the current donor pool. Furthermore, the genetic engineering of stem cells provides a translational approach to HLA-match a limited number of third-party donors with a wide number of recipients.
Asunto(s)
Desoxirribonucleasas/genética , Eliminación de Gen , Antígenos HLA-A/genética , Trasplante de Células Madre Hematopoyéticas/etnología , Células Madre Hematopoyéticas/inmunología , Alelos , Animales , Desoxirribonucleasas/metabolismo , Selección de Donante/ética , Expresión Génica , Ingeniería Genética/métodos , Antígenos HLA-A/inmunología , Antígenos HLA-B/genética , Antígenos HLA-B/inmunología , Antígenos HLA-C/genética , Antígenos HLA-C/inmunología , Cadenas HLA-DRB1/genética , Cadenas HLA-DRB1/inmunología , Accesibilidad a los Servicios de Salud/ética , Trasplante de Células Madre Hematopoyéticas/ética , Células Madre Hematopoyéticas/citología , Prueba de Histocompatibilidad , Humanos , Ratones , Grupos Raciales , Trasplante Heterólogo , Trasplante Homólogo , Donante no Emparentado , Dedos de ZincRESUMEN
Gene therapy with genetically modified human CD34(+) hematopoietic stem and progenitor cells (HSPCs) may be safer using targeted integration (TI) of transgenes into a genomic 'safe harbor' site rather than random viral integration. We demonstrate that temporally optimized delivery of zinc finger nuclease mRNA via electroporation and adeno-associated virus (AAV) 6 delivery of donor constructs in human HSPCs approaches clinically relevant levels of TI into the AAVS1 safe harbor locus. Up to 58% Venus(+) HSPCs with 6-16% human cell marking were observed following engraftment into mice. In HSPCs from patients with X-linked chronic granulomatous disease (X-CGD), caused by mutations in the gp91phox subunit of the NADPH oxidase, TI of a gp91phox transgene into AAVS1 resulted in â¼15% gp91phox expression and increased NADPH oxidase activity in ex vivo-derived neutrophils. In mice transplanted with corrected HSPCs, 4-11% of human cells in the bone marrow expressed gp91phox. This method for TI into AAVS1 may be broadly applicable to correction of other monogenic diseases.