Publications
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Nowrouzi A, Cheung WT, Li T, et al., 2013, The Fetal Mouse Is a Sensitive Genotoxicity Model That Exposes Lentiviral-associated Mutagenesis Resulting in Liver Oncogenesis, MOLECULAR THERAPY, Vol: 21, Pages: 324-337, ISSN: 1525-0016
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- Citations: 17
Themis M, 2012, Monitoring for potential adverse effects of prenatal gene therapy: genotoxicity analysis in vitro and on small animal models ex vivo and in vivo., Methods in molecular biology, Vol: 891, Pages: 341-370
Gene delivery by integrating vectors has the potential to cause genotoxicity in the host by insertional mutagenesis (IM). Previously, the risk of IM by replication incompetent retroviral vectors was believed to be small. However, the recent observation of leukaemic events due to gamma retroviral vector insertion and activation of the LMO-2 proto-oncogene in patients enrolled in the French and British gene therapy trials for X-SCID demonstrates the need to understand vector associated genotoxicity in greater detail. These findings have led to the development of in vitro, ex vivo, and in vivo assays designed to predict genotoxic risk and to further our mechanistic understanding of this process at the molecular level. In vitro assays include transformation of murine haematopoietic stem cells by integrating retroviral (RV) or lentiviral (LV) vectors and measurement of cell survival resulting from transformation due to integration mainly into the Evi1 oncogene. Ex vivo assays involve harvesting haematopoietic stem cells from mice followed by gene transfer and re-infusion of RV or LV infected cells to reconstitute the immune system. Insertional mutagenesis is then determined by analysis of clonally dominant populations of cells. The latter model has also been made highly sensitive using cells from mice predisposed to oncogenesis by lack of the P53 and Rb pathways. Our investigations on fetal gene therapy discovered a high incidence of liver tumour development that appears to be associated with vector insertions into cancer-related genes. Many genes involved in growth and differentiation are actively transcribed in early developmental and are therefore in an open chromatin configuration, which favours provirus insertion. Some of these genes are known oncogenes or anti-oncogenes and are not usually active during adulthood. We found that in utero injection of primate HIV-1, HR'SIN-cPPT-S-FIX-W does not result in oncogenesis as opposed to administration of non-primate equine
Coutelle C, Waddington SN, Themis M, 2012, Monitoring for potential adverse effects of prenatal gene therapy: mouse models for developmental aberrations and inadvertent germ line transmission., Vol: 891, Pages: 329-340
So far no systematic studies have been conducted to investigate developmental aberrations after prenatal gene transfer in mice. Here, we suggest procedures for such observations to be applied, tested and improved in further in utero gene therapy experiments. They are based on our own experience in husbandry for transgenic human diseases mouse models and breading, rearing, and observing mice after fetal gene transfer as well as on the systematic screens for monitoring of knock-out mutant mouse phenotypes established in international mutagenesis projects (EUMORPHIA and EUMODIC and subsequently the International Mouse Phenotyping Consortium). We also describe here the analysis procedures for detection of germ line mutations based on quantitative PCR (qPCR) by sperm-DNA analysis and breeding studies.
Al-Allaf FA, Coutelle C, Waddington SN, et al., 2010, LDLR-Gene therapy for familial hypercholesterolaemia: problems, progress, and perspectives., Int Arch Med, Vol: 3
Coronary artery diseases (CAD) inflict a heavy economical and social burden on most populations and contribute significantly to their morbidity and mortality rates. Low-density lipoprotein receptor (LDLR) associated familial hypercholesterolemia (FH) is the most frequent Mendelian disorder and is a major risk factor for the development of CAD. To date there is no cure for FH. The primary goal of clinical management is to control hypercholesterolaemia in order to decrease the risk of atherosclerosis and to prevent CAD. Permanent phenotypic correction with single administration of a gene therapeutic vector is a goal still needing to be achieved. The first ex vivo clinical trial of gene therapy in FH was conducted nearly 18 years ago. Patients who had inherited LDLR gene mutations were subjected to an aggressive surgical intervention involving partial hepatectomy to obtain the patient's own hepatocytes for ex vivo gene transfer with a replication deficient LDLR-retroviral vector. After successful re-infusion of transduced cells through a catheter placed in the inferior mesenteric vein at the time of liver resection, only low-level expression of the transferred LDLR gene was observed in the five patients enrolled in the trial. In contrast, full reversal of hypercholesterolaemia was later demonstrated in in vivo preclinical studies using LDLR-adenovirus mediated gene transfer. However, the high efficiency of cell division independent gene transfer by adenovirus vectors is limited by their short-term persistence due to episomal maintenance and the cytotoxicity of these highly immunogenic viruses. Novel long-term persisting vectors derived from adeno-associated viruses and lentiviruses, are now available and investigations are underway to determine their safety and efficiency in preparation for clinical application for a variety of diseases. Several novel non-viral based therapies have also been developed recently to lower LDL-C serum levels in FH patients. This article re
Abbaszadeh F, Clingen PH, Arlett CF, et al., 2010, A novel splice variant of the DNA-PKcs gene is associated with clinical and cellular radiosensitivity in a patient with xeroderma pigmentosum, Journal of Medical Genetics, Vol: 47, Pages: 176-181, ISSN: 0022-2593
David AL, Abi-Nader KN, Weisz B, et al., 2010, Ultrasonographic development of the fetal sheep stomach and evaluation of early gestation ultrasound-guided in utero intragastric injection., Taiwan J Obstet Gynecol, Vol: 49, Pages: 23-29
OBJECTIVE: Safely targeting the fetal gastrointestinal tract during early gestation is essential to develop effective prenatal gene therapy for gastrointestinal diseases. In this study, we aimed to characterize the development of the fetal sheep stomach sonographically and to determine the optimum gestational age, as well as the shortterm morbidity and mortality of early-gestation ultrasound-guided intragastric injection. MATERIALS AND METHODS: In experiments investigating ultrasound-guided prenatal gene therapy, we studied the size and development of the stomach of 185 sheep fetuses (33-144 days' gestational age [GA]; term is 145 days). Ultrasound-guided intragastric injection was performed in 12 fetuses at 55-62 days' GA and postmortem examinations were performed 48 hours later. RESULTS: The stomach was not visible at or before 40 days' GA, but it was seen in all fetuses at 55 days' GA or more. The anteroposterior, transverse and longitudinal diameters of the stomach increased in a quasi-linear fashion throughout gestation. Intragastric injection was successful in 10 out of the 11 fetuses (91%) injected at 60-62 days' GA, with nine fetuses (91%) surviving this procedure. CONCLUSION: In the early-gestation sheep fetus, ultrasound-guided intragastric injection has a good success rate with a low short-term mortality and morbidity.
Kennea NL, Waddington SN, Chan J, et al., 2009, Differentiation of human fetal mesenchymal stem cells into cells with an oligodendrocyte phenotype., Cell Cycle, Vol: 7, Pages: 1069-1079
The potential of mesenchymal stem cells (MSC) to differentiate into neural lineages has raised the possibility of autologous cell transplantation as a therapy for neurodegenerative diseases. We have identified a population of circulating human fetal mesenchymal stem cells (hfMSC) that are highly proliferative and can readily differentiate into mesodermal lineages such as bone, cartilage, fat and muscle. Here, we demonstrate for the first time that primary hfMSC can differentiate into cells with an oligodendrocyte phenotype both in vitro and in vivo. By exposing hfMSC to neuronal conditioned medium or by introducing the pro-oligodendrocyte gene, Olig-2, hfMSC adopted an oligodendrocyte-like morphology, expressed oligodendrocyte markers and appeared to mature appropriately in culture. Importantly we also demonstrate the differentiation of a clonal population of hfMSC into both mesodermal (bone) and ectodermal (oligodendrocyte) lineages. In the developing murine brain transplanted hfMSC integrated into the parenchyma but oligodendrocyte differentiation of these naïve hfMSC was very low. However, the proportion of cells expressing oligodendrocyte markers increased significantly (from 0.2% to 4%) by preexposing the cells to differentiation medium in vitro prior to transplantation. Importantly, the process of in vivo differentiation occurred without cell fusion. These findings suggest that hfMSC may provide a potential source of oligodendrocytes for study and potential therapy.
Buckley SMK, Waddington SN, Jezzard S, et al., 2008, Intra-amniotic delivery of CFTR-expressing adenovirus does not reverse cystic fibrosis phenotype in inbred CFTR-knockout mice, MOLECULAR THERAPY, Vol: 16, Pages: 819-824, ISSN: 1525-0016
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- Citations: 23
Siapati EK, Bigger BW, Kashofer K, et al., 2008, Murine leukemia following irradiation conditioning for transplantation of lentivirally-modified hematopoietic stem cells., European Journal of Haematology, Vol: 4, Pages: 303-313
Emerging reports are conclusively demonstrating the mutagenic risks involved in using retroviral vectors for gene therapy. Animal studies, as well as cases from a human clinical trial, have proven the potential of insertional leukemogenesis caused by a retroviral vector. Here, we report the observation of six T-lymphoblastic leukemia cases arising during the course of a gene therapy study for hemophilia B after transplantation of ex vivo transduced hematopoietic stem cells (HSCs) by a lentivirus vector. Three of these animals comprised secondary recipients of the same donor and LAM-PCR was performed to identify the vector integration loci. We located integrations in repeat elements of known genes, including a candidate brain-tumor locus, but none of these clones could be tracked in the leukemic blasts. Although transduced clones with an intact proviral cassette were detected in the spleen of the leukemic animals, they comprised a very small proportion, not correlating to the levels of leukemic blasts. After propagation of the latter in NOD/SCID mice, we could no longer detect the proviral cassette suggesting that the leukemic blasts were untransduced. We did, however, detect increased levels of reverse transcriptase activity in the leukemic blasts which may suggest activation of endogenous retroviruses. This study demonstrates that tumors arising in these type of gene therapy protocols are not necessarily due to vector insertional mutagenesis and highlights the importance of careful functional studies to delineate the nature of tumorigenesis.
Buckley SM, Waddington SN, Jezzard S, et al., 2008, Intra-amniotic delivery of CFTR-expressing adenovirus does not reverse cystic fibrosis phenotype in inbred CFTR-knockout mice., Molecular Therapy, Vol: 5, Pages: 819-824
Due to its early onset and severe prognosis, cystic fibrosis (CF) has been suggested as a candidate disease for in utero gene therapy. In 1997, a study was published claiming that to how transient prenatal expression of CF transmembrane conductance regulator (CFTR) from an in utero-injected adenovirus vector could achieve permanent reversal of the CF intestinal pathology in adult CF knockout mice, despite the loss of CFTR transgene expression by birth. This would imply that the underlying cause of CF is a prenatal defect for which lifelong cure can be achieved by transient prenatal expression of CFTR. Despite criticism at the time of publication, no independent verification of this contentious finding has been published so far. This is vital for the development of future therapeutic strategies as it may determine whether CF gene therapy should be performed prenatally or postnatally. We therefore reinvestigated this finding with an identical adenoviral vector and a knockout CF mouse line (Cftr(tmlCam)) with a completely inbred genetic background to eliminate any effects due to genetic variation. After delivery of the CFTR-expressing adenovirus to the fetal mouse, both vector DNA and transgenic CFTR expression were detected in treated animals postpartum but statistically no significant difference in survival was observed between the Cftr(-/-) mice treated with the CFTR-adenovirus and those treated with the control vector.
Chan J, Waddington SN, O'Donoghue K, et al., 2007, Widespread distribution and muscle differentiation of human fetal mesenchymal stem cells after intrauterine transplantation in dystrophic mdx mouse., Stem Cells, Vol: 4, Pages: 875-884
Duchenne muscular dystrophy (DMD) is a common X-linked disease resulting from the absence of dystrophin in muscle. Affected boys suffer from incurable progressive muscle weakness, leading to premature death. Stem cell transplantation may be curative, but is hampered by the need for systemic delivery and immune rejection. To address these barriers to stem cell therapy in DMD, we investigated a fetal-to-fetal transplantation strategy. We investigated intramuscular, intravascular, and intraperitoneal delivery of human fetal mesenchymal stem cells (hfMSCs) into embryonic day (E) 14-16 MF1 mice to determine the most appropriate route for systemic delivery. Intramuscular injections resulted in local engraftment, whereas both intraperitoneal and intravascular delivery led to systemic spread. However, intravascular delivery led to unexpected demise of transplanted mice. Transplantation of hfMSCs into E14-16 mdx mice resulted in widespread long-term engraftment (19 weeks) in multiple organs, with a predilection for muscle compared with nonmuscle tissues (0.71% vs. 0.15%, p < .01), and evidence of myogenic differentiation of hfMSCs in skeletal and myocardial muscle. This is the first report of intrauterine transplantation of ontologically relevant hfMSCs into fully immunocompetent dystrophic fetal mice, with systemic spread across endothelial barriers leading to widespread long-term engraftment in multiple organ compartments. Although the low-level of chimerism achieved is not curative for DMD, this approach may be useful in other severe mesenchymal or enzyme deficiency syndromes, where low-level protein expression may ameliorate disease pathology.
David AL, Peebles DM, Gregory L, et al., 2006, Clinically applicable procedure for gene delivery to fetal gut by ultrasound-guided gastric injection: toward prenatal prevention of early-onset intestinal diseases., Hum Gene Ther, Vol: 17, Pages: 767-779, ISSN: 1043-0342
Targeting gene therapy vectors to the fetal intestinal tract could provide a novel means toward prevention of the early postnatal intestinal pathology of cystic fibrosis and other conditions, such as congenital enteropathy, that cause intestinal failure. Among these conditions, cystic fibrosis is by far the most common lethal genetic disease. It is caused by a functional absence or deficiency of the cystic fibrosis transmembrane conductance regulator and manifests in the gut as meconium ileus. Prenatal treatment of genetic disease may avoid early-onset tissue damage and immune sensitization, and may target cells that are less accessible in the adult. We investigated gene transfer to the fetal gut, using a minimally invasive injection technique. First-generation replication-deficient adenoviral vectors encoding the beta-galactosidase gene and transduction-enhancing agents were injected into the stomach of early-gestation fetal sheep (n = 8, 60 days of gestation; term, 145 days) under ultrasound guidance. Reporter gene expression was observed 2 days after injection in the villi of the gastrointestinal epithelia after 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside staining and beta-galactosidase immunohistochemistry of fetal tissues. Expression of beta-galactosidase, as measured by enzyme-linked immunosorbent assay, was enhanced after pretreatment of the fetal gut with sodium caprate, which opens tight junctions, and after adenovirus complexation with DEAE-dextran, which confers a positive charge to the virus. Instillation of the fluorocarbon perflubron after virus delivery resulted in tissue transduction from the fetal stomach to the colon. Using a clinically relevant technique, we have demonstrated widespread gene transfer to the fetal gastrointestinal epithelia.
David AL, Weisz B, Gregory L, et al., 2006, Ultrasound-guided injection and occlusion of the trachea in fetal sheep, ULTRASOUND IN OBSTETRICS & GYNECOLOGY, Vol: 28, Pages: 82-88, ISSN: 0960-7692
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- Citations: 15
Themis M, Waddington SN, Schmidt M, et al., 2006, Corrigendum to "Oncogenesis Following Delivery of a Nonprimate Lentiviral Gene Therapy Vector to Fetal and Neonatal Mice"., Mol Ther, Vol: 13
Bigger BW, Siapati EK, Mistry A, et al., 2006, Permanent partial phenotypic correction and tolerance in a mouse model of hemophilia B by stem cell gene delivery of human factor IX, GENE THERAPY, Vol: 13, Pages: 117-126, ISSN: 0969-7128
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- Citations: 48
Coutelle C, Themis M, Waddington SN, et al., 2005, Gene therapy progress and prospects: Fetal gene therapy - first proofs of concept - some adverse effects, GENE THERAPY, Vol: 12, Pages: 1601-1607, ISSN: 0969-7128
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- Citations: 43
Themis M, Waddington SN, Schmidt M, et al., 2005, Oncogenesis following delivery of a nonprimate lentiviral gene therapy vector to fetal and neonatal mice, MOLECULAR THERAPY, Vol: 12, Pages: 763-771, ISSN: 1525-0016
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- Citations: 182
Weisz B, David AL, Gregory LG, et al., 2005, Targeting the respiratory muscles of fetal sheep for prenatal gene therapy for Duchenne muscular dystrophy, AMERICAN JOURNAL OF OBSTETRICS AND GYNECOLOGY, Vol: 193, Pages: 1105-1109, ISSN: 0002-9378
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- Citations: 12
Siapati EK, Bigger BW, Miskin J, et al., 2005, Comparison of HIV- and EIAV-based vectors on their efficiency in transducing murine and human hematopoietic repopulating cells, MOLECULAR THERAPY, Vol: 12, Pages: 537-546, ISSN: 1525-0016
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- Citations: 26
Buckley SMK, Waddington SN, Jezzard S, et al., 2005, Factors influencing adenovirus-mediated airway transduction in fetal mice, MOLECULAR THERAPY, Vol: 12, Pages: 484-492, ISSN: 1525-0016
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- Citations: 30
Tolmachov O, Ma YL, Themis M, et al., 2005, Overexpression of connexin 43 using a retroviral vector improves electrical coupling of skeletal myoblasts with cardiac myocytes in vitro., BMC Cardiovascular Disorders, Vol: 25
BACKGROUND:Organ transplantation is presently often the only available option to repair a damaged heart. As heart donors are scarce, engineering of cardiac grafts from autologous skeletal myoblasts is a promising novel therapeutic strategy. The functionality of skeletal muscle cells in the heart milieu is, however, limited because of their inability to integrate electrically and mechanically into the myocardium. Therefore, in pursuit of improved cardiac integration of skeletal muscle grafts we sought to modify primary skeletal myoblasts by overexpression of the main gap-junctional protein connexin 43 and to study electrical coupling of connexin 43 overexpressing myoblasts to cardiac myocytes in vitro.METHODS:To create an efficient means for overexpression of connexin 43 in skeletal myoblasts we constructed a bicistronic retroviral vector MLV-CX43-EGFP expressing the human connexin 43 cDNA and the marker EGFP gene. This vector was employed to transduce primary rat skeletal myoblasts in optimised conditions involving a concomitant use of the retrovirus immobilising protein RetroNectin and the polycation transduction enhancer Transfectam. The EGFP-positive transduced cells were then enriched by flow cytometry.RESULTS:More than four-fold overexpression of connexin 43 in the transduced skeletal myoblasts, compared with non-transduced cells, was shown by Western blotting. Functionality of the overexpressed connexin 43 was demonstrated by microinjection of a fluorescent dye showing enhanced gap-junctional intercellular transfer in connexin 43 transduced myoblasts compared with transfer in non-transduced myoblasts. Rat cardiac myocytes were cultured in multielectrode array culture dishes together with connexin 43/EGFP transduced skeletal myoblasts, control non-transduced skeletal myoblasts or alone. Extracellular field action potential activation rates in the co-cultures of connexin 43 transduced skeletal myoblasts with cardiac myocytes were significantly higher than in the
Waddington SN, Kramer MG, Hernandez-Alcoceba R, et al., 2005, <i>In utero</i> gene therapy:: Current challenges and perspectives, MOLECULAR THERAPY, Vol: 11, Pages: 661-676, ISSN: 1525-0016
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- Citations: 33
Waddington SN, Nivsarkar MS, Mistry AR, et al., 2004, Permanent phenotypic correction of hemophilia B in immunocompetent mice by prenatal gene therapy, BLOOD, Vol: 104, Pages: 2714-2721, ISSN: 0006-4971
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- Citations: 100
Waddington SN, Kennea NL, Buckley SMK, et al., 2004, Fetal and neonatal gene therapy: benefits and pitfalls., Gene Ther, Vol: 11 Suppl 1, Pages: S92-S97, ISSN: 0969-7128
The current approaches to gene therapy of monogenetic diseases into mature organisms are confronted with several problems including the following: (1) the underlying genetic defect may have already caused irreversible pathological changes; (2) the level of sufficient protein expression to ameliorate or prevent the disease requires prohibitively large amounts of gene delivery vector; (3) adult tissues may be poorly infected by conventional vector systems dependent upon cellular proliferation for optimal infection, for example, oncoretrovirus vectors; (4) immune responses, either pre-existing or developing following vector delivery, may rapidly eliminate transgenic protein expression and prevent future effective intervention. Early gene transfer, in the neonatal or even fetal period, may overcome some or all of these obstacles. The mammalian fetus enjoys a uniquely protected environment in the womb, bathed in a biochemically and physically supportive fluid devoid of myriad extra-uterine pathogens. Strong physical and chemical barriers to infection might, perhaps, impede the frenetic cell division. The physical support and the biochemical support provided by the fetal-maternal placental interface may, therefore, minimize the onset of genetic diseases manifest early in life. The fetal organism must prepare itself for birth, but lacking a mature adaptive immune system may depend upon more primordial immune defences. It is the nature of these defences, and the vulnerabilities they protect, that are poorly understood in the context of gene therapy and might provide useful information for approaches to gene therapy in the young, as well as perhaps the mature organism.
Mellor N, Themis M, Selden C, et al., 2004, Characteristics of murine histidinaemia and its potential for genetic manipulation., Liver Int, Vol: 24, Pages: 354-360, ISSN: 1478-3223
BACKGROUND: Histidinaemia is an autosomal recessive disorder affecting the hepatic enzyme histidine ammonia lyase (histidase) resulting in elevated plasma and urinary histidine and is prototypic of a series of hepatic cytosolic enzyme defects. AIMS: To characterise the physiology of murine histidinaemia with respect to histidine excretion and catabolism, and explore the potential for manipulating cellular and whole body histidase metabolism by gene transfer. MATERIALS AND METHODS: We studied his/his mice which have a G to A substitution in the gene encoding histidase, using both in vitro transduction of isolated hepatocytes by lipofection with wild-type histidase cDNA, and in vivo transduction of whole liver using a retroviral construct. RESULTS AND CONCLUSION: Histidase cDNA expression restored histidase activity in vivo and in vitro towards normal levels, demonstrated both at the cellular level and by whole body metabolic studies, establishing the potential of this model for the development of new gene therapeutic approaches.
Gregory LG, Waddington SN, Holder MV, et al., 2004, Highly efficient EIAV-mediated in utero gene transfer and expression in the major muscle groups affected by Duchenne muscular dystrophy, GENE THERAPY, Vol: 11, Pages: 1117-1125, ISSN: 0969-7128
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- Citations: 32
Waddington SN, Buckley SMK, Bernloehr C, et al., 2004, Reduced toxicity of F-deficient Sendai virus vector in the mouse fetus, GENE THERAPY, Vol: 11, Pages: 599-608, ISSN: 0969-7128
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- Citations: 11
Alison MR, Vig P, Russo F, et al., 2004, Hepatic stem cells: from inside and outside the liver?, CELL PROLIFERATION, Vol: 37, Pages: 1-21, ISSN: 0960-7722
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- Citations: 123
Peebles D, Gregory LG, David A, et al., 2004, Widespread and efficient marker gene expression in the airway epithelia of fetal sheep after minimally invasive tracheal application of recombinant adenovirus in utero, GENE THERAPY, Vol: 11, Pages: 70-78, ISSN: 0969-7128
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- Citations: 39
Coutelle C, Themis M, Waddington S, et al., 2003, The hopes and fears of in utero gene therapy for genetic disease - A review, PLACENTA, Vol: 24, Pages: S114-S121, ISSN: 0143-4004
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- Citations: 20
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