Gene Therapy and Gene Editing for β-Thalassemia

Transamniotic Delivery of Hematopoietic Stem Cells Genetically Modified to Carry a Human Hemoglobin Subunit Beta Gene (HBB) in a Healthy Rodent Model

BACKGROUND

We sought to determine whether transamniotic stem cell therapy (TRASCET) could be a viable alternative for the fetal administration of genetically modified hematopoietic stem cells (HSCs) carrying a human hemoglobin subunit beta gene (hHBB) in a healthy syngeneic rat model.

METHODS

Time-dated pregnant Lewis dams underwent volume-matched intra-amniotic injections in all their fetuses (n = 61) of a suspension of donor HSCs genetically modified with either both a hHBB gene and a firefly luciferase reporter gene (n = 42) or the firefly luciferase reporter gene alone to control for HBB-derived protein interspecies homology (n = 19) on gestational day 17 (E17; term = E21). Donor HSCs consisted of syngeneic cells phenotyped by flow cytometry with successful hHBB transduction confirmed by ELISA prior to administration in vivo. At term, fetal samples from five anatomical sites relevant to hematopoiesis were screened for the presence of human hemoglobin subunit beta by ELISA and by digital droplet PCR (ddPCR).

RESULTS

When controlled by HSCs without hHBB injections, human hemoglobin subunit beta production was documented at term in the fetal bone marrow and spleen (p < 0.001 and p = 0.028 respectively). Positive hHBB expression by ddPCR was detected in the spleen (54 %), bone marrow (46 %), blood (46 %), liver (23 %), and thymus (15 %).

CONCLUSIONS

Genetically modified hematopoietic stem cells carrying a human hemoglobin subunit beta gene can reach fetal hematopoietic sites after simple intra-amniotic injection in a healthy syngeneic rat model. Transamniotic hematopoietic stem cell-based gene therapy could become a novel strategy for the perinatal management of select hemoglobinopathies.

LEVEL OF EVIDENCE

N/A (animal and laboratory study).

TYPE OF STUDY

animal and laboratory study.

Applications of Gene Editing and Nanotechnology in Stem Cell-Based Therapies for Human Diseases

Stem cell research is a dynamic and fast-advancing discipline with great promise for the treatment of diverse human disorders. The incorporation of gene editing technologies, including ZFNs, TALENs, and the CRISPR/Cas system, in conjunction with progress in nanotechnology, is fundamentally transforming stem cell therapy and research. These innovations not only provide a glimmer of optimism for patients and healthcare practitioners but also possess the capacity to radically reshape medical treatment paradigms. Gene editing and nanotechnology synergistically enhance stem cell-based therapies' precision, efficiency, and applicability, offering transformative potential for treating complex diseases and advancing regenerative medicine. Nevertheless, it is important to acknowledge that these technologies also give rise to ethical considerations and possible hazards, such as inadvertent genetic modifications and the development of genetically modified organisms, therefore creating a new age of designer infants. This review emphasizes the crucial significance of gene editing technologies and nanotechnology in the progress of stem cell treatments, particularly for degenerative pathologies and injuries. It emphasizes their capacity to restructure and comprehensively revolutionize medical treatment paradigms, providing fresh hope and optimism for patients and healthcare practitioners.

Beta thalassemia syndromes: New insights

Beta thalassemia (β-thalassemia) syndromes are a heterogeneous group of inherited hemoglobinopathies caused by molecular defects in the beta-globin gene that lead to the impaired synthesis of beta-globin chains of the hemoglobin. The hallmarks of the disease include ineffective erythropoiesis, chronic hemolytic anemia, and iron overload. Clinical presentation ranges from asymptomatic carriers to severe anemia requiring lifelong blood transfusions with subsequent devastating complications. The management of patients with severe β-thalassemia represents a global health problem, particularly in low-income countries. Until recently, management strategies were limited to regular transfusions and iron chelation therapy, with allogeneic hematopoietic stem cell transplantation available only for a subset of patients. Better understanding of the underlying pathophysiological mechanisms of β-thalassemia syndromes and associated clinical phenotypes has paved the way for novel therapeutic options, including pharmacologic enhancers of effective erythropoiesis and gene therapy.

Advancing CRISPR genome editing into gene therapy clinical trials: progress and future prospects

Genome editing has recently evolved from a theoretical concept to a powerful and versatile set of tools. The discovery and implementation of CRISPR-Cas9 technology have propelled the field further into a new era. This RNA-guided system allows for specific modification of target genes, offering high accuracy and efficiency. Encouraging results are being announced in clinical trials employed in conditions like sickle cell disease (SCD) and transfusion-dependent beta-thalassaemia (TDT). The path finally led the way to the recent FDA approval of the first gene therapy drug utilising the CRISPR/Cas9 system to edit autologous CD34+ haematopoietic stem cells in SCD patients (Casgevy). Ongoing research explores the potential of CRISPR technology for cancer therapies, HIV treatment and other complex diseases. Despite its remarkable potential, CRISPR technology faces challenges such as off-target effects, suboptimal delivery systems, long-term safety concerns, scalability, ethical dilemmas and potential repercussions of genetic alterations, particularly in the case of germline editing. Here, we examine the transformative role of CRISPR technologies, including base editing and prime editing approaches, in modifying the genetic and epigenetic codes in the human genome and provide a comprehensive focus, particularly on relevant clinical applications, to unlock the full potential and challenges of gene editing.

Revolutionizing animal husbandry: Breakthroughs in gene editing delivery systems

Gene editing technology has become an essential tool for advancing breeding practices, enhancing disease resistance, and boosting productivity in animal husbandry. Despite its potential, the delivery of gene editing reagents into cells faces several challenges, including low targeting efficiency, immunogenicity, and cytotoxicity, which have hindered its wider application in the field. This review discusses the evolution of gene editing technologies and highlights recent advancements in various delivery methods used in animal husbandry. It critically evaluates the strengths and weaknesses of these different delivery approaches while identifying potential directions for future development. The goal is to equip researchers with effective strategies to optimize delivery methods, ultimately facilitating the implementation and progress of gene editing technologies in animal husbandry.

A retrospective analysis of autoimmune hemolytic anemia after allogeneic hematopoietic stem cell transplantation for transfusion-dependent β-thalassemia: focus on T and B lymphocyte reconstitution

BACKGROUND

Autoimmune hemolytic anemia (AIHA) following allogeneic hematopoietic stem cell transplantation (allo-HSCT) is often refractory and relapsing, leading to increased mortality post-HSCT.

METHODS

We retrospectively analyzed the cases of patients with transfusion-dependent β-thalassemia (TDT) who underwent allo-HSCT to study their clinical features, the occurrence of AIHA post-HSCT, and treatment response and to explore the possible pathogenesis of AIHA.

RESULT

A total of 113 patients were registered in the study, out of whom 14 developed AIHA following allo-HSCT, resulting in a cumulative incidence of 12.4%. The median age at HSCT was 5 (range: 2-14) years, and the median time of occurrence was 8 (range: 4-17) months after HSCT. Patients who are less than 4 years old at the time of HSCT (P = 0.032) exhibit a higher incidence of AIHA. Compared to patients without AIHA, AIHA patients demonstrate a lower percentage of B lymphocytes at the first 100 days (day + 100) post-HSCT(P = 0.002). There were no statistically significant differences in gender, unrelated donors, HLA incomplete mismatch, iron overload, ABO incompatibility, cytomegalovirus (CMV) reactivation, Epstein Barr virus (EBV) reactivation, acute and chronic graft-versus-host disease (GvHD). When AIHA occurred, the absolute value of regulatory T cells decreased without a clear reduction in the proportion of CD4 + cells, and there was no significant elevation of interleukin-17. Eventually, 78.6% (11/14) of patients achieved complete remission with corticosteroids and rituximab, and patients who failed were efficacious with the bortezomib in combination with corticosteroids. Four patients experienced relapse, with one of them relapsing twice. Two patients relapsed after bortezomib and subsequently achieved remission with retreatment using a combination of corticosteroids and rituximab. All AIHA patients were alive and without relapse at the follow-up cutoff.

CONCLUSIONS

Patients suffering from TDT are more prone to developing AIHA following allo-HSCT, potentially due to a disruption in the reconstitution balance of T and B lymphocytes. Despite the high incidence, the response to treatment was excellent. For relapsed/refractory patients, alternate therapy with bortezomib and rituximab may be considered.

Advances in CRISPR-Cas technology and its applications: revolutionising precision medicine

CRISPR-Cas (Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR-associated proteins) has undergone marked advancements since its discovery as an adaptive immune system in bacteria and archaea, emerged as a potent gene-editing tool after the successful engineering of its synthetic guide RNA (sgRNA) toward the targeting of specific DNA sequences with high accuracy. Besides its DNA editing ability, further-developed Cas variants can also edit the epigenome, rendering the CRISPR-Cas system a versatile tool for genome and epigenome manipulation and a pioneering force in precision medicine. This review explores the latest advancements in CRISPR-Cas technology and its therapeutic and biomedical applications, highlighting its transformative impact on precision medicine. Moreover, the current status of CRISPR therapeutics in clinical trials is discussed. Finally, we address the persisting challenges and prospects of CRISPR-Cas technology.

Revolutionizing cattle breeding: Gene editing advancements for enhancing economic traits

Beef and dairy products are rich in protein and amino acids, making them highly nutritious for human consumption. The increasing use of gene editing technology in agriculture has paved the way for genetic improvement in cattle breeding via the development of the CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein) system. Gene sequences are artificially altered and employed in the pursuit of improving bovine breeding research through targeted knockout, knock-in, substitution, and mutation methods. This review offers a comprehensive analysis of the advancements in gene editing technology and its diverse applications in enhancing both quantitative and qualitative traits across livestock. These applications encompass areas such as meat quality, milk quality, fertility, disease resistance, environmental adaptability, sex control, horn development, and coat colour. Furthermore, the review considers prospective ideas and insights that may be employed to refine breeding traits, enhance editing efficiency, and navigate the ethical considerations associated with these advancements. The review's focus on improving the quality of beef and milk is intended to enhance the economic viability of these products. Furthermore, it constitutes a valuable resource for scholars and researchers engaged in the fields of cattle genetic improvement and breeding.

Genetic Modifiers of Hemoglobin Expression from a Clinical Perspective in Hemoglobinopathy Patients with Beta Thalassemia and Sickle Cell Disease

Hemoglobinopathies, namely β-thalassemia and sickle cell disease (SCD), are hereditary diseases, characterized by molecular genetic aberrations in the beta chains of hemoglobin. These defects affect the normal production of hemoglobin with severe anemia due to less or no amount of beta globins in patients with β-thalassemia (quantitative disorder), while SCD is a serious disease in which a mutated form of hemoglobin distorts the red blood cells into a crescent shape at low oxygen levels (qualitative disorder). Despite the revolutionary progress in recent years with the approval of gene therapy and gene editing for specific patients, there is an unmet need for highlighting the mechanisms influencing hemoglobin production and for the development of novel drugs and targeted therapies. The identification of the transcription factors and other genetic modifiers of hemoglobin expression is of utmost importance for discovering novel therapeutic approaches for patients with hemoglobinopathies. The aim of this review is to describe these complex molecular mechanisms and pathways affecting hemoglobin expression and to highlight the relevant investigational approaches or pharmaceutical interventions focusing on restoring the hemoglobin normal function by linking the molecular background of the disease with the clinical perspective. All the associated drugs increasing the hemoglobin expression in patients with hemoglobinopathies, along with gene therapy and gene editing, are also discussed.

Interventions to reduce the risk of side-effects of cancer treatments in childhood

INTRODUCTION

Childhood cancers as a group affect around 1 in 500 children but each individual diagnosis is a rare disease. While research largely focuses on improving cure rates, the management of side effects of treatment are high priority for clinicians, families and children and young people.

AREAS COVERED

The prevention and efficient management of infectious complications, oral mucositis, nausea and vomiting and graft-vs-host disease illustrated with examples of implementation research, translation of engineering to care, advances in statistical methodologies, and traditional bench-to-patient development. The reviews draw from existing systematic reviews and well conducted clinical practice guidelines.

EXPERT OPINION

The four areas are driven from patient and family priorities. Some of the problems outlined are ready for proven interventions, others require us to develop new technologies. Advancement needs us to make the best use of new methods of applied health research and clinical trial methodologies. Some of the greatest challenges may be those we're not fully aware of, as new therapies move from their use in adult oncological practice into children. This will need us to continue our collaborative, multi-professional, multi-disciplinary and eclectic approach.

Gene Therapy: A Revolutionary Step in Treating Thalassemia

Beta thalassemia is an inherited blood disorder that results in inefficient erythropoiesis due to genetic mutation that leads to the reduction or absence of the hemoglobin beta-globulin protein. Approximately 8.5% of UAE residents suffer from β-thalassemia, a significant health and financial problem. The treatment options available for β-Thalassemia major are limited and associated with a wide range of complications. β-thalassemia gene therapy is emerging as a potential novel treatment option that eliminates the complications caused by the current long-term treatment modalities and the associated economic burden. This paper reviews the scientific literature related to emerging gene therapy for β-Thalassemia by analyzing all the articles published from January 2010 to December 2023 in the English language on Databases like PubMed, Scopus, ProQuest, and CINAHL. The use of gene therapy has demonstrated promising outcomes for a permanent cure of β-Thalassemia. To conclude, gene therapy is an innovative solution. It demonstrates a promising future, but does come with its own setbacks and is something that must be tackled in order to revolutionize it in the medical world. FDA-approved ZYNTEGLO is a potentially one-time curative treatment for β-Thalassemia. Although cutting-edge, its use is limited because of the high cost-a price of USD 2.8 million per patient.

Cavitation is the determining mechanism for the atomization of high-viscosity liquid

Piezoelectric atomization is becoming mainstream in the field of inhalation therapy due to its significant advantages. With the rapid development of high-viscosity gene therapy drugs, the demand for piezoelectric atomization devices is increasing. However, conventional piezoelectric atomizers with a single-dimensional energy supply are unable to provide the energy required to atomize high-viscosity liquids. To address this problem, our team has designed a flow tube internal cavitation atomizer (FTICA). This study focuses on dissecting the atomization mechanism of FTICA. In contrast to the widely supported capillary wave hypothesis, our study provides evidence in favor of the cavitation hypothesis, proving that cavitation is the key to atomizing high-viscosity liquids with FTICA. In order to prove that the cavitation is the key to atomizing in the structure of FTICA, the performance of atomization is experimented after changing the cavitation conditions by heating and stirring of the liquids.

C2H2 Zinc Finger Transcription Factors Associated with Hemoglobinopathies

In humans, specific aberrations in β-globin results in sickle cell disease and β-thalassemia, symptoms of which can be ameliorated by increased expression of fetal globin (HbF). Two recent CRISPR-Cas9 screens, centered on ∼1500 annotated sequence-specific DNA binding proteins and performed in a human erythroid cell line that expresses adult hemoglobin, uncovered four groups of candidate regulators of HbF gene expression. They are (1) members of the nucleosome remodeling and deacetylase (NuRD) complex proteins that are already known for HbF control; (2) seven C2H2 zinc finger (ZF) proteins, including some (ZBTB7A and BCL11A) already known for directly silencing the fetal γ-globin genes in adult human erythroid cells; (3) a few other transcription factors of different structural classes that might indirectly influence HbF gene expression; and (4) DNA methyltransferase 1 (DNMT1) that maintains the DNA methylation marks that attract the MBD2-associated NuRD complex to DNA as well as associated histone H3 lysine 9 methylation. Here we briefly discuss the effects of these regulators, particularly C2H2 ZFs, in inducing HbF expression for treating β-hemoglobin disorders, together with recent advances in developing safe and effective small-molecule therapeutics for the regulation of this well-conserved hemoglobin switch.

Impact of α-Globin Gene Expression and α-Globin Modifiers on the Phenotype of β-Thalassemia and Other Hemoglobinopathies: Implications for Patient Management

In this short review, we presented and discussed studies on the expression of globin genes in β-thalassemia, focusing on the impact of α-globin gene expression and α-globin modifiers on the phenotype and clinical severity of β-thalassemia. We first discussed the impact of the excess of free α-globin on the phenotype of β-thalassemia. We then reviewed studies focusing on the expression of α-globin-stabilizing protein (AHSP), as a potential strategy of counteracting the effects of the excess of free α-globin on erythroid cells. Alternative processes controlling α-globin excess were also considered, including the activation of autophagy by β-thalassemia erythroid cells. Altogether, the studies reviewed herein are expected to have a potential impact on the management of patients with β-thalassemia and other hemoglobinopathies for which reduction in α-globin excess is clinically beneficial.

Reducing the transcriptional read-through rate of a lentiviral vector for β-thalassemia gene therapy

BACKGROUND

LentiGlobin BB305 is a self-inactivating lentiviral vector carrying a human β-globin expressing cassette for treating β-thalassemia. Initially, a 2 × 250 bp chicken Locus Control Region fragment of cHS4, functioning as an insulator, was placed at its ΔU3, which was removed after the first clinical trial led by a French team to avoid abnormal splicing, etc. This action could potentially lead to an increasing risk of the transcriptional read-through rate driven by the β-globin promoter to a significant level, posing a biosafety risk in clinical trials.

METHODS

In the present study, a read-through reducing agent (C-U+ or WPRE) was designed to be placed at the 3' UTR of the β-globin gene. The Enhancer Activities and/or Transcriptional Read-Through (EATRT) rate at the mRNA level and the protein expression level regarding lentiviral preparation titer were examined.

RESULTS

We found that the insertion of the element (C-U+ or WPRE) reduced the EATRT effectively by 53% or 41%, respectively. C-U+ has less impact on virus package efficiency. Furthermore, there was no significant difference in the protein expression level after the C-U+ or WPRE insertion.

CONCLUSIONS

The results of the present study show that inserting C-U+ or WPRE before the polyA sequence of the BB305 would reduce the EATRT rate at no cost of its expressing efficacy and viral preparation titers. Thus, we present an alternative improvement for a safer lentiviral vector for β-thalassemia clinical trials.

Human cellular model systems of β-thalassemia enable in-depth analysis of disease phenotype

β-thalassemia is a prevalent genetic disorder causing severe anemia due to defective erythropoiesis, with few treatment options. Studying the underlying molecular defects is impeded by paucity of suitable patient material. In this study we create human disease cellular model systems for β-thalassemia by gene editing the erythroid line BEL-A, which accurately recapitulate the phenotype of patient erythroid cells. We also develop a high throughput compatible fluorometric-based assay for evaluating severity of disease phenotype and utilize the assay to demonstrate that the lines respond appropriately to verified reagents. We next use the lines to perform extensive analysis of the altered molecular mechanisms in β-thalassemia erythroid cells, revealing upregulation of a wide range of biological pathways and processes along with potential novel targets for therapeutic investigation. Overall, the lines provide a sustainable supply of disease cells as research tools for identifying therapeutic targets and as screening platforms for new drugs and reagents.

Normal and dysregulated crosstalk between iron metabolism and erythropoiesis

Erythroblasts possess unique characteristics as they undergo differentiation from hematopoietic stem cells. During terminal erythropoiesis, these cells incorporate large amounts of iron in order to generate hemoglobin and ultimately undergo enucleation to become mature red blood cells, ultimately delivering oxygen in the circulation. Thus, erythropoiesis is a finely tuned, multifaceted process requiring numerous properly timed physiological events to maintain efficient production of 2 million red blood cells per second in steady state. Iron is required for normal functioning in all human cells, the erythropoietic compartment consuming the majority in light of the high iron requirements for hemoglobin synthesis. Recent evidence regarding the crosstalk between erythropoiesis and iron metabolism sheds light on the regulation of iron availability by erythroblasts and the consequences of insufficient as well as excess iron on erythroid lineage proliferation and differentiation. In addition, significant progress has been made in our understanding of dysregulated iron metabolism in various congenital and acquired malignant and non-malignant diseases. Finally, we report several actual as well as theoretical opportunities for translating the recently acquired robust mechanistic understanding of iron metabolism regulation to improve management of patients with disordered erythropoiesis, such as anemia of chronic inflammation, β-thalassemia, polycythemia vera, and myelodysplastic syndromes.

Gene editing without ex vivo culture evades genotoxicity in human hematopoietic stem cells

Gene editing the BCL11A erythroid enhancer is a validated approach to fetal hemoglobin (HbF) induction for β-hemoglobinopathy therapy, though heterogeneity in edit allele distribution and HbF response may impact its safety and efficacy. Here we compared combined CRISPR-Cas9 endonuclease editing of the BCL11A +58 and +55 enhancers with leading gene modification approaches under clinical investigation. We found that combined targeting of the BCL11A +58 and +55 enhancers with 3xNLS-SpCas9 and two sgRNAs resulted in superior HbF induction, including in engrafting erythroid cells from sickle cell disease (SCD) patient xenografts, attributable to simultaneous disruption of core half E-box/GATA motifs at both enhancers. We corroborated prior observations that double strand breaks (DSBs) could produce unintended on- target outcomes in hematopoietic stem and progenitor cells (HSPCs) such as long deletions and centromere-distal chromosome fragment loss. We show these unintended outcomes are a byproduct of cellular proliferation stimulated by ex vivo culture. Editing HSPCs without cytokine culture bypassed long deletion and micronuclei formation while preserving efficient on-target editing and engraftment function. These results indicate that nuclease editing of quiescent hematopoietic stem cells (HSCs) limits DSB genotoxicity while maintaining therapeutic potency and encourages efforts for in vivo delivery of nucleases to HSCs.