Therapeutic Options for Mucopolysaccharidosis II (Hunter Disease)

2020 ◽  
Vol 26 (40) ◽  
pp. 5100-5109
Author(s):  
Francyne Kubaski ◽  
Filippo Vairo ◽  
Guilherme Baldo ◽  
Fabiano de Oliveira Poswar ◽  
Amauri Dalla Corte ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Small Molecules ◽  
Genome Editing ◽  
Fusion Proteins ◽  
Therapeutic Options ◽  
Hematopoietic Stem ◽  
Hunter Disease ◽  
Enzyme Replacement ◽  
Mps Ii ◽  
The Impact

Background: Mucopolysaccharidosis type II (Hunter syndrome, or MPS II) is an X-linked lysosomal disorder caused by the deficiency of iduronate-2-sulfatase, which leads to the accumulation of glycosaminoglycans (GAGs) in a variety of tissues, resulting in a multisystemic disease that can also impair the central nervous system (CNS). Objective: This review focuses on providing the latest information and expert opinion about the therapies available and under development for MPS II. Methods: We have comprehensively revised the latest studies about hematopoietic stem cell transplantation (HSCT), enzyme replacement therapy (ERT - intravenous, intrathecal, intracerebroventricular, and intravenous with fusion proteins), small molecules, gene therapy/genome editing, and supportive management. Results and Discussion: Intravenous ERT is a well-established specific therapy, which ameliorates the somatic features but not the CNS manifestations. Intrathecal or intracerebroventricular ERT and intravenous ERT with fusion proteins, presently under development, seem to be able to reduce the levels of GAGs in the CNS and have the potential of reducing the impact of the neurological burden of the disease. Gene therapy and/or genome editing have shown promising results in preclinical studies, bringing hope for a “one-time therapy” soon. Results with HSCT in MPS II are controversial, and small molecules could potentially address some disease manifestations. In addition to the specific therapeutic options, supportive care plays a major role in the management of these patients. Conclusion: At this time, the treatment of individuals with MPS II is mainly based on intravenous ERT, whereas HSCT can be a potential alternative in specific cases. In the coming years, several new therapy options that target the neurological phenotype of MPS II should be available.

scholarly journals Genome Editing Strategies to Treat Beta-Hemoglobinopathies

Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. SCI-16-SCI-16
Author(s):  
Mitchell J Weiss
Keyword(s):  
Gene Therapy ◽  
Genome Editing ◽  
Conflicts Of Interest ◽  
Gene Mutations ◽  
Fetal Hemoglobin ◽  
Beta Thalassemia ◽  
Great Promise ◽  
Globin Genes ◽  
Hematopoietic Stem ◽  
Medical Therapies

Genetic forms of anemia caused by HBB gene mutations that impair beta globin production are extremely common worldwide. The resultant disorders, mainly sickle cell disease (SCD) and beta-thalassemia, cause substantial morbidity and early mortality. Treatments for these diseases include medical therapies and bone marrow transplantation (BMT), which can be curative. However, medical therapies are suboptimal and BMT is associated with serious toxicities, particularly because HLA-matched allogeneic sibling donors are not available for most patients. Thus, new therapies are urgently needed for millions of affected individuals. Gene therapy offers great promise to cure SCD and beta thalassemia and emerging genome editing technologies represent a new form of gene therapy. Approaches to cure SCD and beta-thalassemia via genome editing include: 1) Correction of HBB mutations by homology directed repair (HDR); 2) use of non-homologous end joining (NHEJ) to activate gamma globin production and raise fetal hemoglobin (HbF) levels; 3) NHEJ to disrupt alpha-globin genes (HBA1 or HBA2) and thereby alleviate globin chain imbalance in intermediately severe forms of beta thalassemia. Challenges for these approaches include selection of the most effective genome editing tools, optimizing their delivery to hematopoietic stem cells (HSCs), improving specificity and better understanding potential off target effects, particularly those that are biologically relevant. Technologies for genome editing are advancing rapidly and being tested in preclinical models for HBB-mutated disorders. Ultimately, however, the best strategies can only be identified in clinical trials. This will require close collaborations between basic/translational researchers who study genome editing, clinical hematologists and collaboration between experts in academia and the bio-pharmaceutical industry. Disclosures No relevant conflicts of interest to declare.

scholarly journals Human Genetic Diversity Alters Therapeutic Gene Editing Off-Target Outcomes

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3993-3993
Author(s):  
Linda Yingqi Lin ◽  
Samuele Cancellieri ◽  
Jing Zeng ◽  
Francesco Masillo ◽  
My Anh Nguyen ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Clinical Trials ◽  
Genome Editing ◽  
Gene Editing ◽  
Conflicts Of Interest ◽  
African Ancestry ◽  
Great Promise ◽  
Personal Genome ◽  
Hematopoietic Stem ◽  
The Impact

Abstract CRISPR gene editing holds great promise to modify somatic genomes to ameliorate disease. In silico prediction of homologous sites coupled with biochemical evaluation of possible genomic off-targets may predict genotoxicity risk of individual gene editing reagents. However, standard computational and biochemical methods focus on reference genomes and do not consider the impact of genetic diversity on off-target potential. Here we developed a web application called CRISPRme that explicitly and efficiently integrates human genetic variant datasets with orthogonal genomic annotations to predict and prioritize off-target sites at scale. The method considers both single-nucleotide variants (SNVs) and indels, accounts for bona fide haplotypes, accepts spacer:protospacer mismatches and bulges, and is suitable for personal genome analyses. We tested the tool with a guide RNA (gRNA) targeting the BCL11A erythroid enhancer that has shown therapeutic promise in clinical trials for sickle cell disease (SCD) and β-thalassemia (Frangoul et al. NEJM 2021). We find that the top predicted off-target site is produced by a non-reference allele common in African-ancestry populations (rs114518452, minor allele frequency (MAF) = 4.5%) that introduces a protospacer adjacent motif (PAM) for SpCas9. We validate that SpCas9 generates indels (~9.6% frequency) and chr2 pericentric inversions in a strictly allele-specific manner in edited CD34+ hematopoietic stem/progenitor cells (HSPCs), although a high-fidelity Cas9 variant mitigates this off-target. This report illustrates how population and private genetic variants should be considered as modifiers of genome editing outcomes. We expect that variant-aware off-target assessment will be required for therapeutic genome editing efforts going forward, including both ongoing and future clinical trials, and we provide a powerful approach for comprehensive off-target prediction. CRISPRme is available at crisprme.di.univr.it. Disclosures No relevant conflicts of interest to declare.

scholarly journals Improving Precise CRISPR Genome Editing by Small Molecules: Is there a Magic Potion?

Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1318 ◽  
Author(s):  
Nadja Bischoff ◽  
Sandra Wimberger ◽  
Marcello Maresca ◽  
Cord Brakebusch
Keyword(s):  
Gene Therapy ◽  
Dna Repair ◽  
Animal Models ◽  
Molecular Biology ◽  
Small Molecules ◽  
Genome Editing ◽  
Drug Targets ◽  
Targeted Mutagenesis ◽  
Dna Repair Mechanisms ◽  
Repair Mechanisms

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) genome editing has become a standard method in molecular biology, for the establishment of genetically modified cellular and animal models, for the identification and validation of drug targets in animals, and is heavily tested for use in gene therapy of humans. While the efficiency of CRISPR mediated gene targeting is much higher than of classical targeted mutagenesis, the efficiency of CRISPR genome editing to introduce defined changes into the genome is still low. Overcoming this problem will have a great impact on the use of CRISPR genome editing in academic and industrial research and the clinic. This review will present efforts to achieve this goal by small molecules, which modify the DNA repair mechanisms to facilitate the precise alteration of the genome.

ADA-deficient SCID is associated with a specific microenvironment and bone phenotype characterized by RANKL/OPG imbalance and osteoblast insufficiency

Blood ◽  
2009 ◽  
Vol 114 (15) ◽  
pp. 3216-3226 ◽  
Author(s):  
Aisha V. Sauer ◽  
Emanuela Mrak ◽  
Raisa Jofra Hernandez ◽  
Elena Zacchi ◽  
Francesco Cavani ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Bone Marrow ◽  
Severe Combined Immunodeficiency ◽  
Intrinsic Defect ◽  
Combined Immunodeficiency ◽  
Hematopoietic Stem ◽  
Enzyme Replacement ◽  
Bone Phenotype

Abstract Adenosine deaminase (ADA) deficiency is a disorder of the purine metabolism leading to combined immunodeficiency and systemic alterations, including skeletal abnormalities. We report that ADA deficiency in mice causes a specific bone phenotype characterized by alterations of structural properties and impaired mechanical competence. These alterations are the combined result of an imbalanced receptor activator of nuclear factor-κB ligand (RANKL)/osteoprotegerin axis, causing decreased osteoclastogenesis and an intrinsic defect of osteoblast function with subsequent low bone formation. In vitro, osteoblasts lacking ADA displayed an altered transcriptional profile and growth reduction. Furthermore, the bone marrow microenvironment of ADA-deficient mice showed a reduced capacity to support in vitro and in vivo hematopoiesis. Treatment of ADA-deficient neonatal mice with enzyme replacement therapy, bone marrow transplantation, or gene therapy resulted in full recovery of the altered bone parameters. Remarkably, untreated ADA–severe combined immunodeficiency patients showed a similar imbalance in RANKL/osteoprotegerin levels alongside severe growth retardation. Gene therapy with ADA-transduced hematopoietic stem cells increased serum RANKL levels and children's growth. Our results indicate that the ADA metabolism represents a crucial modulatory factor of bone cell activities and remodeling. The trials were registered at www.clinicaltrials.gov as #NCT00598481 and #NCT00599781.

scholarly journals Reactivation of γ-globin in adult β-YAC mice after ex vivo and in vivo hematopoietic stem cell genome editing

Blood ◽  
2018 ◽  
Vol 131 (26) ◽  
pp. 2915-2928 ◽  
Author(s):  
Chang Li ◽  
Nikoletta Psatha ◽  
Pavel Sova ◽  
Sucheol Gil ◽  
Hongjie Wang ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Stem Cell ◽  
Binding Site ◽  
Genome Editing ◽  
Ex Vivo ◽  
Hematopoietic Stem ◽  
Key Points ◽  
Cell Genome ◽  
Hsc Transplantation

Key Points CRISPR/Cas9-mediated disruption of a BCL11A binding site in HSCs of β-YAC mice results in the reactivation of γ-globin in erythrocytes. Our approach for in vivo HSC genome editing that does not require HSC transplantation and myeloablation should simplify HSC gene therapy.

scholarly journals Innovative Treatments for Mucopolysaccharidoses

2018 ◽  
Vol 08 (01) ◽  
pp. e163-e171
Author(s):  
Florian Lagler
Keyword(s):  
Small Molecules ◽  
Drug Distribution ◽  
Enzyme Concentration ◽  
Hematopoietic Stem ◽  
Immune Reactions ◽  
Encapsulated Cells ◽  
Enzyme Replacement ◽  
Emerging Therapies ◽  
Therapeutic Molecules ◽  
Causal Treatment

AbstractMucopolysaccharidoses (MPSs) are caused by deficiency of specific lysosomal enzymes that affect the degradation of mucopolysaccharides or glycosaminoglycans. Since more than 15 years enzyme replacement therapies are available for an increasing number of MPSs. These therapies together with hematopoietic stem cell transplantation today are the gold standard of causal treatment in MPS. Despite confirmed efficacy, both do not cure these severe conditions. In this article, we discuss the limitations of established and promises of emerging therapies. The limitations of intravenous enzyme replacement and cell therapy can be summarized as immune reactions against the therapeutic molecules/cells and the failure to restore enduring and sufficient enzyme concentration in all relevant tissues. Accordingly, innovative approaches comprise small molecules and encapsulated cells that do not activate antitherapeutic immune reactions, several gene therapy approaches that aim for sustained enzyme expression, and new enzymes that penetrate blood–brain and other barriers for drug distribution. This article provides an update on the state of development of these new therapies and highlights enduring challenges.

scholarly journals The therapeutic potential of genome editing for β-thalassemia

F1000Research ◽  
2015 ◽  
Vol 4 ◽  
pp. 1431 ◽  
Author(s):  
Astrid Glaser ◽  
Bradley McColl ◽  
Jim Vadolas
Keyword(s):  
Gene Therapy ◽  
Genome Editing ◽  
Insertional Mutagenesis ◽  
Therapeutic Potential ◽  
Allogeneic Bone Marrow Transplantation ◽  
Lessons Learned ◽  
Small Subset ◽  
Allogeneic Bone ◽  
Hematopoietic Stem ◽  
Blood Disorder

The rapid advances in the field of genome editing using targeted endonucleases have called considerable attention to the potential of this technology for human gene therapy. Targeted correction of disease-causing mutations could ensure lifelong, tissue-specific expression of the relevant gene, thereby alleviating or resolving a specific disease phenotype. In this review, we aim to explore the potential of this technology for the therapy of β-thalassemia. This blood disorder is caused by mutations in the gene encoding the β-globin chain of hemoglobin, leading to severe anemia in affected patients. Curative allogeneic bone marrow transplantation is available only to a small subset of patients, leaving the majority of patients dependent on regular blood transfusions and iron chelation therapy. The transfer of gene-corrected autologous hematopoietic stem cells could provide a therapeutic alternative, as recent results from gene therapy trials using a lentiviral gene addition approach have demonstrated. Genome editing has the potential to further advance this approach as it eliminates the need for semi-randomly integrating viral vectors and their associated risk of insertional mutagenesis. In the following pages we will highlight the advantages and risks of genome editing compared to standard therapy for β-thalassemia and elaborate on lessons learned from recent gene therapy trials.

Long-Term Safety and Efficacy of Stem Cell Gene Therapy for ADA-SCID.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 200-200
Author(s):  
Alessandro Aiuti ◽  
Ulrike Benninghoff ◽  
Barbara Cassani ◽  
Federica Cattaneo ◽  
Luciano Callegaro ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Bone Marrow ◽  
Gene Transfer ◽  
Severe Combined Immunodeficiency ◽  
Hematopoietic Stem ◽  
Enzyme Replacement ◽  
Cell Functions ◽  
Cd34 Cells

Abstract Severe combined immunodeficiency (SCID) due to adenosine deaminase (ADA) deficiency is a fatal congenital disorder of the immune system associated with systemic toxicity due to accumulation of purine metabolites. We previously showed that retroviral-mediated ADA gene transfer into autologous hematopoietic stem/progenitor cells (HSC) allowed restoration of immune and metabolic functions. We have now enrolled eight ADA-SCID children (age: 7–67 months) in our phase I/II gene therapy trial in which HSC are combined with low intensity conditioning with busulfan (total dose 4 mg/Kg i.v.). Previous treatment included haploidentical bone marrow transplant (n=3) or long-term (>1 year) enzyme replacement therapy (PEG-ADA) (n=4) associated with insufficient immune reconstitution or severe autoimmunity. In the latter case, PEG-ADA was discontinued to favour the growth advantage for gene corrected cells. The patients received a median dose of 8.8x106/Kg bone marrow CD34+ cells (range 0.9–10.8), containing on average 26.2±9.6% transduced CFU-C. Five patients experienced ANC <0.5x109/L, which was extended beyond day +30 in two patients. With a median follow up of 3.1 years (range 0.4–5.9), no adverse events related to gene transfer have been observed. Long-term engraftment of transduced HSC was demonstrated by stable multilineage marking, persisting more than 5 years from gene therapy. The average proportion of transduced cells in the peripheral blood at one year post-gene therapy (n=6) was 5% for granulocytes, 95% for T cells, 56% for B cells and 62% for NK cells. Comparison of the insertion sites retrieved ex vivo from patients with those identified in pre-transplant transduced CD34+ cells showed no skewing in the profile of genome distributions or in the gene families hit by the vector, and no clonal expansion. In the six children with a follow-up >1 year after gene therapy, we observed a progressive increase in lymphocyte counts which was sustained over time (median at 1.5 years 1.6x109/L), polyclonal thymopoiesis and normalization of T-cell functions in vitro. Serum Ig levels improved and evidence of antigen-specific antibodies was obtained, leading to IVIG discontinuation in five patients. All the children are currently healthy and thriving, and none of them showed severe infections. Sustained ADA activity in lymphocytes and RBC resulted in a dramatic reduction of RBC purine toxic metabolites (dAXP<30 nmoles/ml in 5 patients) and amelioration of children’s growth and development. In summary, these data confirm that gene therapy is safe and efficacious in correcting both the immune and metabolic defect in ADA-SCID, with proven clinical benefit.

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