DOCSLIB.ORG

Gene Therapy Using Haematopoietic Stem and Progenitor Cells

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Gene Therapy Using Haematopoietic Stem and Progenitor Cells REVIEWS Gene therapy using haematopoietic stem and progenitor cells Giuliana Ferrari1,2, Adrian J. Thrasher3,4 and Alessandro Aiuti 1,2,5 ✉ Abstract | Haematopoietic stem and progenitor cell (HSPC) gene therapy has emerged as an effective treatment modality for monogenic disorders of the blood system such as primary immunodeficiencies and β- thalassaemia. Medicinal products based on autologous HSPCs corrected using lentiviral and gammaretroviral vectors have now been approved for clinical use, and the site- specific genome modification of HSPCs using gene editing techniques such as CRISPR–Cas9 has shown great clinical promise. Preclinical studies have shown engineered HSPCs could also be used to cross- correct non-haematopoietic cells in neurodegenerative metabolic diseases. Here, we review the most recent advances in HSPC gene therapy and discuss emerging strategies for using HSPC gene therapy for a range of diseases. 7 Allogeneic Haematopoietic stem cell (HSC) transplantation copies of a therapeutic gene . Once reinfused, genetically Relating to or denoting that (HSCT) has been a routine procedure for treating inborn modified HSPCs undergo self- renewal and establish a the source of cells, tissues or errors of metabolism and the blood system for more population of modified cells, which pass the transgene organs for transplant is from an than 50 years1,2. The first successful transplantations for to daughter blood cells on differentiation (Fig. 1). The individual genetically different from the recipient. the treatment of immune disorders were conducted in first proof- of- concept HSPC gene therapy studies were 1968 using allogeneic stem cells to treat X- linked severe conducted in the 1990s to address adenosine deami- Primary immunodeficiencies combined immunodeficiency (SCID- X1), an inherited nase (ADA) deficiency SCID (ADA- SCID); although (PIDs). Mendelian genetic disease caused by inactivating mutations in the gene correction was successful, the efficiency of correction disorders caused by defects encoding interleukin-2 receptor subunit- γ (IL2RG), and in these studies was low9–12. Improvements in ex vivo in the development and/or function of immune cells. Wiskott–Aldrich syndrome, a rare X- linked recessive culture techniques and new engineering approaches Currently, more than 300 immunodeficiency characterized by thrombocytopenia, using long terminal repeat (LTR)- driven gammaretro- genes have been identified that eczema and recurrent infections3,4. Extraordinary pro- viral vectors have since resulted in clinical benefit in cause adaptive and/or innate gress has been made in allogeneic HSCT, and it is now many primary immunodeficiencies (PIDs)13,14; however, immune cell defects. used for many genetic diseases in an increasing number the occurrence of T cell acute lymphoblastic leukaemia of patients. Improvements have been made with regard following gene therapy in a significant proportion of 1Vita- Salute San Raffaele to donor matching, strategies for more effective control patients — caused by insertional mutagenesis into the University, Milan, Italy. of graft-versus- host disease, more effective conditioning LMO2 locus — led to a substantial slowdown of all ex 15,16 2San Raffaele Telethon regimens and better management of toxicity and infec- vivo gene therapy approaches . The development of 7 Institute for Gene Therapy, tions. However, the availability of immunocompatible self-inactivating lentiviral vectors as a delivery platform IRCCS San Raffaele Scientific donors with optimal human leukocyte antigen (HLA) has since enabled safer and more effective insertion of Institute, Milan, Italy. genotype matching can limit its application5, and mor- therapeutic genes into HSPCs. 3Molecular and Cellular bidity owing to graft- versus- host disease remains as a Over the past two decades, advances in our under- Immunology Section, UCL result of the use of unmatched donors. As a result, gene standing of disease biology and gene transfer technology Great Ormond Street Institute of Child Health, London, UK. therapy techniques based on the genetic modification have been translated into remarkable clinical successes (FIG. 2) 4Great Ormond Street of autologous haematopoietic stem and progenitor cells . As a result, the field has attracted significant com- Hospital for Children (HSPCs) have been explored. mercial interest, and two products have secured regula- NHS Foundation Trust, Autologous HSPC gene therapy has been investi- tory approval by the European Medicines Agency (EMA) London, UK. gated for the prevention or treatment of monogenic in Europe — namely Strimvelis for use in ADA- SCID 5Pediatric Immunohematology disorders associated with altered blood cell maturation and Zynteglo for use in patients older than 12 years with Unit, IRCCS San Raffaele and function, such as diseases of the innate and adap- transfusion- dependent β- thalassaemia — with several Scientific Institute, Milan, Italy. tive immune systems, red blood cell disorders, plate- others expected to follow in both Europe and the United 6–8 ✉e- mail: alessandro.aiuti@ let disorders and bone marrow failure syndromes . States in the next 5 years. More than 300 patients have hsr.it HSPC gene therapy techniques to date have employed now been treated with HSPC gene therapy in clinical https://doi.org/10.1038/ ex vivo gene transfer, through transduction of the trials, and robust evidence for the durability of cor- s41576-020-00298-5 patients’ own HSPCs with a vector carrying one or more rected HSPC treatments and their long- term safety and NATURE REVIEWS | GENETICS REVIEWS LT-HSC Self- renewal ST-HSC Self- renewal Haematopoietic stem cells Fanconi anaemia CD34+ cells MPP CLP CMP LMMP PreB MEP GMP CDP PreT Haematopoietic progenitor cells Thymus Bone marrow Peripheral blood Erythrocytes Platelets Granulocytes • Monocytes Dendritic cells B cell NK cell CD4+ CD8+ • Macrophages Tissues T cell T cell Haemoglobinopathies Wiskott– Chronic Pyruvate kinase Aldrich granulomatous SCID CID deficiency syndrome disease Erythroid lineage Myeloid lineages Lymphoid lineages Mature haematopoietic cells Fig. 1 | The haematopoietic hierarchy and genetic disorders. Bone marker analyses, in vitro and in vivo functional assays, clonal tracking by marrow- resident haematopoietic stem cells and haematopoietic insertion analyses in haematopoietic stem and progenitor cell gene therapy progenitor cells replenish blood and tissues with new mature cells. Both studies and single- cell RNA analyses (reviewed previously22). Mendelian haematopoietic stem cells and haematopoietic progenitor cells express genetic disorders can affect self- renewal, differentiation and/or the the cell surface marker CD34, which is used to enrich a mixture of function of different blood and immune cells. Examples of genetic diseases haematopoietic stem and progenitor cells for transplantation and gene for which gene therapy is under investigation or approved are represented therapy. Haematopoietic stem cells can be classed as long- term in white boxes below affected cell types. Wiskott–Aldrich syndrome affects haematopoietic stem cells (LT- HSCs) or short- term haematopoietic stem platelets and other lineages. CDP, common dendritic progenitor; CID, cells (ST- HSCs). ST- HSCs progressively acquire lineage specifications in combined immunodeficiency; CLP, common lymphoid progenitor; CMP, order to differentiate into lineage-committed progenitors and eventually common myeloid progenitor; GMP, granulomonocytic progenitor; LMMP, terminally differentiated cells, which are released into the peripheral blood. lymphoid- myeloid primed progenitor; MEP, megakaryocytic–erythroid A simplified scheme of human haematopoiesis is presented here. progenitor; MPP, multipotent progenitor; NK cell, natural killer cell; preB, Alternative models have been postulated on the basis of cell surface pre- B cell; preT, pre-T cell; SCID; severe combined immunodeficiency. clinical efficacy has been obtained for PIDs, including current gene addition approaches. Finally, we discuss the SCID- X1, ADA- SCID, Wiskott–Aldrich syndrome, application of HSPC gene therapy for different diseases, chronic granulomatous disease (CGD), β- thalassaemia, including the use of HSPCs as delivery vehicles for ther- metachromatic leukodystrophy (MLD) and X- linked apeutic proteins, and conclude by considering remaining adrenoleukodystrophy (X- ALD) (Table 1). challenges in the field and future perspectives. Here, we review the most recent advances in Chronic granulomatous HSPC gene therapy. We begin with an overview of the Ex vivo gene transfer disease ex vivo gene transfer process, from HSPC collection and HSPC collection (CGD). A disease caused by genetic modification to engraftment and long-term clonal Autologous HSPCs are collected either through mul- dysfunction of the phagocyte tracking. We discuss recent technological developments tiple aspirations from the iliac crests or leukapheresis NADPH oxidase, a mobilizing agents (Fig. 3) membrane- bound enzyme in gene editing, which will help move the field forward following the administration of , + complex required for effective to the next generation of medicinal products, broaden- and collected material is enriched for CD34 cells. killing of bacteria and fungi. ing the field of application to disorders not amenable to Both procedures yield a mixture of non- engrafting www.nature.com/nrg REVIEWS Leukapheresis cells and a heterogenous population of primitive and studies between the two sources are lacking. However, A
Load more

Recommended publications
  • CADTH ISSUES in EMERGING HEALTH TECHNOLOGIES Informing Decisions About New Health Technologies
    CADTH ISSUES IN EMERGING HEALTH TECHNOLOGIES Informing Decisions About New Health Technologies Issue Mar 171 2018 Gene Therapy: An Overview of Approved and Pipeline Technologies CADTH ISSUES IN EMERGING HEALTH TECHNOLOGIES 1 Authors: Alison Sinclair, Saadul Islam, Sarah Jones Cite as: Gene therapy: an overview of approved and pipeline technologies. Ottawa: CADTH; 2018 Mar. (CADTH issues in emerging health technologies; issue 171). Acknowledgments: Louis de Léséleuc, Jeff Mason, Teo Quay, Joanne Kim, Lesley Dunfield, Eftyhia Helis, Iryna Magega, Jane Hurge ISSN: 1488-6324 (online) Disclaimer: The information in this document is intended to help Canadian health care decision-makers, health care professionals, health systems leaders, and policy- makers make well-informed decisions and thereby improve the quality of health care services. While patients and others may access this document, the document is made available for informational purposes only and no representations or warranties are made with respect to its fitness for any particular purpose. The information in this document should not be used as a substitute for professional medical advice or as a substitute for the application of clinical judgment in respect of the care of a particular patient or other professional judgment in any decision-making process. The Canadian Agency for Drugs and Technologies in Health (CADTH) does not endorse any information, drugs, therapies, treatments, products, processes, or services. While CADTH has taken care to ensure that the information prepared by it in this document is accurate, complete, and up-to-date as at the applicable date the material was first published by CADTH, CADTH does not make any guarantees to that effect.
    [Show full text]
  • Bone Marrow (Stem Cell) Transplant for Sickle Cell Disease Bone Marrow (Stem Cell) Transplant
    Bone Marrow (Stem Cell) Transplant for Sickle Cell Disease Bone Marrow (Stem Cell) Transplant for Sickle Cell Disease 1 Produced by St. Jude Children’s Research Hospital Departments of Hematology, Patient Education, and Biomedical Communications. Funds were provided by St. Jude Children’s Research Hospital, ALSAC, and a grant from the Plough Foundation. This document is not intended to take the place of the care and attention of your personal physician. Our goal is to promote active participation in your care and treatment by providing information and education. Questions about individual health concerns or specifi c treatment options should be discussed with your physician. For more general information on sickle cell disease, please visit our Web site at www.stjude.org/sicklecell. Copyright © 2009 St. Jude Children’s Research Hospital How did bone marrow (stem cell) transplants begin for children with sickle cell disease? Bone marrow (stem cell) transplants have been used for the treatment and cure of a variety of cancers, immune system diseases, and blood diseases for many years. Doctors in the United States and other countries have developed studies to treat children who have severe sickle cell disease with bone marrow (stem cell) transplants. How does a bone marrow (stem cell) transplant work? 2 In a person with sickle cell disease, the bone marrow produces red blood cells that contain hemoglobin S. This leads to the complications of sickle cell disease. • To prepare for a bone marrow (stem cell) transplant, strong medicines, called chemotherapy, are used to weaken or destroy the patient’s own bone marrow, stem cells, and infection fi ghting system.
    [Show full text]
  • Genetic Manipulation of Stem Cells Eleni Papanikolaou1,2*, Kalliopi I
    logy & Ob o st ec e tr n i y c s G Papanikolaou et al. Gynecol Obstetric 2011, S:6 Gynecology & Obstetrics DOI: 10.4172/2161-0932.S6-001 ISSN: 2161-0932 Review Article Open Access Genetic Manipulation of Stem Cells Eleni Papanikolaou1,2*, Kalliopi I. Pappa1,3 and Nicholas P. Anagnou1,2 1Laboratory of Cell and Gene Therapy, Centre for Basic Research, Biomedical Research Foundation of the Academy of Athens (BRFAA), Athens, Greece 2Laboratory of Biology, University of Athens School of Medicine, Athens, Greece 3First Department of Obstetrics and Gynecology, University of Athens School of Medicine, Alexandra Hospital, Athens, Greece Abstract Stem cells have the remarkable potential for self-renewal and differentiation into many cell types in the body during early life and development. In addition, in many tissues they constitute a source of internal repair system, dividing essentially without limit to replenish damaged or dead cells. After division, each new cell has the potential either to retain the stem cell status or to differentiate to a more specialized cell type, such as a red blood cell, a brain cell or a heart cell. Until recently, three types of stem cells from animals and humans have been characterized, i.e. embryonic stem cells, fetal stem cells and somatic adult stem cells. However, in late 2007, researchers accomplished another breakthrough by identifying conditions that allow some specialized adult cells to be “reprogrammed” genetically to assume a stem cell-like state. These cells, called induced pluripotent stem cells (iPSCs), express genes and factors important for maintaining the unique properties and features of embryonic stem cells.
    [Show full text]
  • Genetics and Stem Cell Research A.Genetics
    7: Genetics and Stem Cell Research A.Genetics 1. Introduction The principal special feature of genetics research is that the result of the study applies not only to the proband but also influences her lineage both in the past and in the future. For example genetic studies demonstrated Thomas Jefferson’s sexual relationship with his slave Sally Hemings and defined their descendants to this day. As we all know from television, genetic studies can be done from any tissue fragment that contains DNA so that studies of surgical specimens, biopsy materials, hair, epithelium and blood samples can all be utilized for extensive genetic studies. 2. Sampling Some DNA is more medically valuable than other. Samples from isolated populations in which a particular disorder is prevalent have a much greater probability of yielding the causal gene(s) because they have fewer genome variations than in the general population. Once isolated, the genetic material associated with the disorder has a good chance of yielding novel diagnostic and/or therapeutic approaches for the disorder. 3. Property rights A persistent question is whether the providers of the genetic material have any rights to the products created from their genetic material. These days, most consent forms are written explicitly to exclude intellectual property rights from the subjects. As might be imagined, this smacks of exploitation in the developing world. Negotiation of a monetary return to the community has sometimes been concluded. Important and lucrative products have been derived from individuals’ genomes without their receiving royalties or other compensation. However, the knowledge, technical expertise, and capital needed to make a useful product from a blood or tissue sample come from the company not the donor.
    [Show full text]
  • The Amazing Stem Cell What Are They? Where Do They Come From? How Are They Changing Medicine? Stem Cells Are “Master Cells”
    The Amazing Stem Cell What are they? Where do they come from? How are they changing medicine? Stem cells are “master cells” Stem cells can be “guided” to become many other cell types. Stem Cell Bone cell Self-renewed stem cell Brain cell Heart muscle Blood cell cell There are several types of stem cells, each from a unique source Embryonic stem cells* • Removed from embryos created for in vitro fertilization after donation consent is given. (Not sourced from aborted fetuses.) • Embryos are 3-5 days old (blastocyst) and have about 150 cells. • Can become any type of cell in the body, also called pluripotent cells. • Can regenerate or repair diseased tissue and organs. • Current use limited to eye-related disorders. * Not used by Mayo Clinic. Adult stem cells • Found in most adult organs and tissues, including bone marrow. • Often taken from bone marrow in the hip. • Blood stem cells can be collected through apheresis (separated from blood). • Can regenerate and repair diseased or damaged tissues (regenerative medicine). • Can be used as specialized “drugs” to potentially treat degenerative conditions. • Currently tested in people with neurological and heart disease. Umbilical cord blood stem cells • Found in blood in placenta and umbilical cord after childbirth. • Have the ability to change into specialized cells (like blood cells), also called progenitor cells. • Parents choose to donate umbilical cord blood for use in research, or have it stored for private or public banks. • Can be used in place of bone marrow stem cell transplants in some clinical applications. Bioengineered stem cells • Regular adult cells (e.g., blood, skin) reprogrammed to act like embryonic stem cells (induced pluripotent stem cells).
    [Show full text]
  • The Longest Telomeres: a General Signature of Adult Stem Cell Compartments
    Downloaded from genesdev.cshlp.org on September 25, 2021 - Published by Cold Spring Harbor Laboratory Press The longest telomeres: a general signature of adult stem cell compartments Ignacio Flores,1 Andres Canela,1 Elsa Vera,1 Agueda Tejera,1 George Cotsarelis,2 and María A. Blasco1,3 1Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid E-28029, Spain; 2University of Pennsylvania School of Medicine, M8 Stellar-Chance Laboratories, Philadelphia, Pennsylvania 19104, USA Identification of adult stem cells and their location (niches) is of great relevance for regenerative medicine. However, stem cell niches are still poorly defined in most adult tissues. Here, we show that the longest telomeres are a general feature of adult stem cell compartments. Using confocal telomere quantitative fluorescence in situ hybridization (telomapping), we find gradients of telomere length within tissues, with the longest telomeres mapping to the known stem cell compartments. In mouse hair follicles, we show that cells with the longest telomeres map to the known stem cell compartments, colocalize with stem cell markers, and behave as stem cells upon treatment with mitogenic stimuli. Using K15-EGFP reporter mice, which mark hair follicle stem cells, we show that GFP-positive cells have the longest telomeres. The stem cell compartments in small intestine, testis, cornea, and brain of the mouse are also enriched in cells with the longest telomeres. This constitutes the description of a novel general property of adult stem cell compartments. Finally, we make the novel finding that telomeres shorten with age in different mouse stem cell compartments, which parallels a decline in stem cell functionality, suggesting that telomere loss may contribute to stem cell dysfunction with age.
    [Show full text]
  • Nano-Biosensor for Monitoring the Neural Differentiation of Stem Cells
    nanomaterials Review Nano-Biosensor for Monitoring the Neural Differentiation of Stem Cells Jin-Ho Lee 1,2,†, Taek Lee 1,2,† and Jeong-Woo Choi 1,2,* 1 Department of Chemical and Biomolecular Engineering, Sogang University, 35 Baekbeom-ro (Sinsu-dong), Mapo-gu, Seoul 121-742, Korea; [email protected] (J.-H.L.); [email protected] (T.L.) 2 Institute of Integrated Biotechnology, Sogang University, 35 Baekbeom-ro (Sinsu-dong), Mapo-gu, Seoul 121-742, Korea * Correspondence: [email protected]; Tel.: +82-2-718-1976; Fax: +82-2-3273-0331 † These authors contributed equally to this work. Academic Editors: Chen-Zhong Li and Ling-Jie Meng Received: 6 July 2016; Accepted: 17 November 2016; Published: 28 November 2016 Abstract: In tissue engineering and regenerative medicine, monitoring the status of stem cell differentiation is crucial to verify therapeutic efficacy and optimize treatment procedures. However, traditional methods, such as cell staining and sorting, are labor-intensive and may damage the cells. Therefore, the development of noninvasive methods to monitor the differentiation status in situ is highly desirable and can be of great benefit to stem cell-based therapies. Toward this end, nanotechnology has been applied to develop highly-sensitive biosensors to noninvasively monitor the neural differentiation of stem cells. Herein, this article reviews the development of noninvasive nano-biosensor systems to monitor the neural differentiation of stem cells, mainly focusing on optical (plasmonic) and eletrochemical methods. The findings in this review suggest that novel nano-biosensors capable of monitoring stem cell differentiation are a promising type of technology that can accelerate the development of stem cell therapies, including regenerative medicine.
    [Show full text]
  • Stem Cell Research: an Overview
    Biochemistry & Molecular Biology Letters Review | Vol 3 Iss 2 Stem Cell Research: An Overview Shatadru Bhattacharjee* Department of Pharmacognosy, Dr. BC Roy College of Pharmacy, West Bengal, India *Corresponding author: Shatadru B, Dr. BC Roy College of Pharmacy, West Bengal, India, Email- [email protected] Received: March 03, 2017; Accepted: March 19, 2017; Published: March 24, 2017 Abstract A primary cell can reproduce itself or give rise to more specialized cell type is known as stem cell. The stem cell is the primogenitor at the top of the family tree among all type of cell [1-7]. One blood stem cell gives birth to red blood cells (RBC), white cells (WBC) and platelets stem cells that vary in their developmental capacity. A multi-potent stem cell can give birth to several types of mature cell. A pluripotent stem cell can give birth to all types of adult tissue cells and extra embryonic tissue cells which support embryonic development inside fetus[8-14]. A totipotent stem cell can give birth to a new individual given appropriate maternal support. The current growth of stem cell research is quiet good from last few decades. Stem cell therapy has capabilities of regenerating any human tissue damaged by injury, disease or ageing could be available within a few years. In this review there are few discussion related to current stem cell research and development [15-21]. Keywords: Stem cell; Regenerative medicine; Cell biology Introduction Stem cells have the remarkable potential in the development of several different type of cell in the body during early life and growth [22-28].
    [Show full text]
  • Basic Pluripotent Stem Cell Culture Protocols Maria Borowski∗, Maria Giovino-Doherty, Lan Ji, Meng-Jiao Shi, Kelly P
    Basic pluripotent stem cell culture protocols Maria Borowski∗, Maria Giovino-Doherty, Lan Ji, Meng-Jiao Shi, Kelly P. Smith and Joseph Laning, Massachusetts Stem Cell Bank, University of Massachusetts Medical School, Shrewsbury, MA 01545 USA Abstract Stem cell research is a rapidly expanding field with the potential to develop therapeutic agents to treat diseases as well as study disease development from early stages. The culture of human pluripotent stem cells shares many of the same protocols as standard mammalian cell culture. However, the successful culture and maintenance of human pluripotent stem cells (hPSCs) in an undifferentiated state requires additional consider- ations to ensure that cells maintain their key characteristics of self-renewal and pluripotency. There are several basic techniques needed for the culturing of mammalian cells, including thawing frozen stocks, plating cells in culture vessels, changing media, passaging and cryopreservation. The protocols in this document represent a subset of the standard operating procedures used to maintain and culture stem cells at the Massachusetts Human Stem Cell Bank, and have been thoroughly testing and verified. A Stem cell culture considerations Stem cell research is a rapidly expanding field with the potential to develop therapeutic agents to treat diseases as well as study disease development from early stages. However, to fulfill this promise, researchers need to have access to standardized protocols for the development, maintenance and differentiation of these unique cells. Such “best practices” will allow comparisons of different studies and hasten the refinement of these techniques. Such standardization can be driven by resources such as StemBook and by stem cell banks.
    [Show full text]
  • Stem Cell Therapy and Gene Transfer for Regeneration
    Gene Therapy (2000) 7, 451–457 2000 Macmillan Publishers Ltd All rights reserved 0969-7128/00 $15.00 www.nature.com/gt MILLENNIUM REVIEW Stem cell therapy and gene transfer for regeneration T Asahara, C Kalka and JM Isner Cardiovascular Research and Medicine, St Elizabeth’s Medical Center, Tufts University School of Medicine, Boston, MA, USA The committed stem and progenitor cells have been recently In this review, we discuss the promising gene therapy appli- isolated from various adult tissues, including hematopoietic cation of adult stem and progenitor cells in terms of mod- stem cell, neural stem cell, mesenchymal stem cell and ifying stem cell potency, altering organ property, accelerating endothelial progenitor cell. These adult stem cells have sev- regeneration and forming expressional organization. Gene eral advantages as compared with embryonic stem cells as Therapy (2000) 7, 451–457. their practical therapeutic application for tissue regeneration. Keywords: stem cell; gene therapy; regeneration; progenitor cell; differentiation Introduction poietic stem cells to blood cells. The determined stem cells differentiate into ‘committed progenitor cells’, which The availability of embryonic stem (ES) cell lines in mam- retain a limited capacity to replicate and phenotypic fate. malian species has greatly advanced the field of biologi- In the past decade, researchers have defined such com- cal research by enhancing our ability to manipulate the mitted stem or progenitor cells from various tissues, genome and by providing model systems to examine including bone marrow, peripheral blood, brain, liver cellular differentiation. ES cells, which are derived from and reproductive organs, in both adult animals and the inner mass of blastocysts or primordial germ cells, humans (Figure 1).
    [Show full text]
  • Transgenic Organisms Transgenic Animals
    Transgenic Organisms • A transgenic organism is one into which a gene from some other species has been transferred. • Transgenic organisms are examples of genetically modified organisms (GMO’s). • The transferred gene is called a transgene. • A transgene, like any other gene, indirectly codes for a protein, which corresponds to a particular trait. • Because of the universality of the genetic code, a transgene will allow the transgenic organism to produce the same protein (and therefore exhibit the same trait) as the original, “donor” organism. • Transgenes are introduced into the recipient organism’s germ line. 1 Transgenic Animals • Most transgenic animals are fruit flies and mice, but others are produced, including rabbits, pigs, goats, cattle, and sheep. • There are two predominate reasons for producing transgenic animals: • Economic benefit • Models for disease • Transgenic animals are produced by one of three primary methods: • Microinjection of DNA • Retrovirus mediation • Embryonic stem-cell mediation 2 Microinjection of DNA • DNA containing the transgene is injected into the pronucleus of a gamete. • The transgenic gamete is used for in vitro fertilization. • The resulting embryo is implanted into a female. • Transgenic animals are then mated to increase the chance of offspring containing the transgene. • Microinjection has a fairly low success rate. 3 Retrovirus-mediated Gene Transfer • A retrovirus genome is RNA rather than DNA. • The code in the viral RNA is “reverse transcribed” to produce DNA, which is then incorporated into the host cell. • For use in transgenesis, viral RNA is modified and the viri are introduced into an animal. • The invading viri cause the animal cells to produce and incorporate DNA corresponding to the viral RNA.
    [Show full text]
  • Twenty-Five Years of Gene Therapy for ADA-SCID: from Bubble Babies to an Approved Drug
    Twenty-Five Years of Gene Therapy for ADA-SCID: From Bubble Babies to an Approved Drug Francesca Ferrua1,2 and Alessandro Aiuti1,2,* 1San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), Pediatric Immunohematology and Bone Marrow Transplantation Unit, San Raffaele Scientific Institute, Milan, Italy;2Vita-Salute San Raffaele University, Milan, Italy. Twenty-five years have passed since first attempts of gene therapy (GT) in children affected by severe combined immunodeficiency (SCID) due to adenosine deaminase (ADA) defect, also known by the general public as bubble babies. ADA-SCID is fatal early in life if untreated. Unconditioned hematopoietic stem cell (HSC) transplant from matched sibling donor represents a curative treatment but is available for few patients. Enzyme replacement therapy can be life-saving, but its chronic use has many drawbacks. This review summarizes the history of ADA-SCID GT over the last 25 years, starting from first pioneering studies in the early 1990s using gamma-retroviral vectors, based on multiple infusions of genetically corrected autologous peripheral blood lymphocytes. HSC represented the ideal target for gene correction to guarantee production of engineered multi-lineage progeny, but it required a decade to achieve thera- peutic benefit with this approach. Introduction of low-intensity conditioning represented a crucial step in achieving stable gene-corrected HSC engraftment and therapeutic levels of ADA-expressing cells. Recent clinical trials demonstrated that gamma-retroviral GT for ADA-SCID has a favorable safety profile and is effective in restoring normal purine metabolism and immune functions in patients >13 years after treatment. No abnormal clonal proliferation or leukemia development have been observed in >40 patients treated experimentally in five different centers worldwide.
    [Show full text]