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Gene therapy is expected to become a promising treatment, and potentially even a cure, for hemophilia. After several years of research, the first gene therapy product has been granted conditional market authorization by the European Union in August 2022. The recent progress in the field also has implications on the ethical aspects of hemophilia gene therapy. Reviews conducted in the 2000s mainly identified questions on the ethics of conducting early-phase clinical trials. However, since then, the knowledge on safety and efficacy has improved, and the field has moved toward clinical application, a phase that has its own ethical aspects. Therefore, we conducted a narrative review to take stock of the ethical aspects of hemophilia gene therapy. Based on our analysis of the literature, we identified 3 ethical themes. The theme Living up to expectations describes the existing hopes for gene therapy and the unlikelihood of the currently approved product becoming a permanent cure. In the theme Psychosocial impacts, we discuss the fear that gene therapy will impact the identity of people with hemophilia and their need for psychosocial support. The theme Costs and access discusses the expected cost-effectiveness of gene therapy and its implications on accessibility worldwide. We conclude that it may be necessary to change the narratives surrounding gene therapy, from describing it as a cure to describing it as one of the many treatments that temporarily relieve symptoms and that there is a need to reevaluate the desirability of gene therapy for hemophilia, given the availability of other treatments.

Significant pancreatic islet dysfunction and loss shortly after transplantation to the liver limit the widespread implementation of this procedure in the clinic. Nonimmune factors such as reactive oxygen species and inflammation have been considered as the primary driving force for graft failure. The adipokine adiponectin plays potent roles against inflammation and oxidative stress. Previous studies have demonstrated that systemic administration of adiponectin significantly prevented islet loss and enhanced islet function at post-transplantation period. In vitro studies indicate that adiponectin protects islets from hypoxia/reoxygenation injury, oxidative stress as well as TNF-α-induced injury. By applying adenovirus mediated transfection, we now engineered islet cells to express exogenous adiponectin gene prior to islet transplantation. Adenovirus-mediated adiponectin transfer to a syngeneic suboptimal islet graft transplanted under kidney capsule markedly prevented inflammation, preserved islet graft mass and improved islet transplant outcomes. These results suggest that adenovirus-mediated adiponectin gene therapy would be a beneficial clinical engineering approach for islet preservation in islet transplantation.

Small animal models have demonstrated the efficacy of ex vivo regional gene therapy using scaffolds loaded with BMP-2-expressing mesenchymal stem cells (MSCs). Prior to clinical translation, optimization of seeding techniques of the transduced cells will be important to minimize time and resource expenditure, while maximizing cell delivery and BMP-2 production. No prior studies have investigated cell-seeding techniques in the setting of transduced cells for gene therapy applications. Using BMP-2-expressing transduced adipose-derived MSCs and a porous ceramic scaffold, this study compared previously described static and dynamic seeding techniques with respect to cell seeding efficiency, uniformity of cell distribution, and in vitro BMP-2 production. Static and negative pressure seeding techniques demonstrated the highest seeding efficiency, while orbital shaking was associated with the greatest increases in BMP-2 production per cell. Low density cell suspensions were associated with the highest seeding efficiency and uniformity of cell distribution, and the greatest increases in BMP-2 production from 2 to 7 days after seeding. Our results highlight the potential for development of an optimized cell density and seeding technique that could greatly reduce the number of MSCs needed to produce therapeutic BMP-2 levels in clinical situations. Further studies are needed to investigate in vivo effects of cell seeding techniques on bone healing.

Gene therapy is emerging as a potential cure for haemophilia. Gene therapy is a one-time treatment that can elevate factor levels for many years and minimize or eliminate the need for clotting factor concentrate (CFC) replacement therapy. However, there is a paucity of reports on gene therapy efforts in countries outside of North America or Europe, especially in low-and-middle-income countries (LMIC). All indications are that gene therapy will be one of standard care treatments for haemophilia in the future. Still, it may not be accessible to many countries due to various barriers and challenges. At the same time, each country may formulate solutions that may be used globally.To summarize the approaches taken to establish haemophilia gene therapy in Japan, China, India, South Africa, and Brazil, and to describe the US-initiated multi-LMIC haemophilia gene therapy development program to include Peru, Vietnam, Thailand, Nepal, and Sri Lanka.A review of related published information or as accessible by each country's author.Different starting conditions, differing input and level of support from the multitude of stakeholders, and strong leadership have led to various approaches for facilitating research and developing needed infrastructure and regulatory and financing models. Gene therapy programs are at various stages of development and include both adeno-associated viral and lentiviral vectors.Global partnerships and collaboration, exchange of knowledge and experience, and alignment of processes across borders will promote further progress towards global access to gene therapy for haemophilia.

Osteogenesis imperfecta (OI) describes a series of genetic bone fragility disorders that can have a substantive impact on patient quality of life. The multidisciplinary approach to management of children and adults with OI primarily involves the administration of antiresorptive medication, allied health (physiotherapy and occupational therapy), and orthopedic surgery. However, advances in gene editing technology and gene therapy vectors bring with them the promise of gene-targeted interventions to provide an enduring or perhaps permanent cure for OI. This review describes emergent technologies for cell- and gene-targeted therapies, major hurdles to their implementation, and the prospects of their future success with a focus on bone disorders. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

There are over 7,000 diseases that are individually rare, but collectively affect millions of people worldwide. They are very commonly neurologic single-gene disorders. Recent advances in recombinant adeno-associated virus vectors have enabled breakthroughs, including US Food and Drug Administration (FDA)-approved gene therapies for inherited retinal dystrophy due to RPE65 mutation and spinal muscular atrophy. A range of other gene therapies for rare neurologic diseases are at various stages of development. Future development of gene editing technologies promises further to broaden the potential for more patients with these disorders to benefit from innovative therapies.

Gene therapy (GT) is becoming a realistic treatment option for patients with haemophilia. Outside clinical trials, the complexity and potential complications of GT will pose unprecedented challenges to haemophilia care centres.To explore the potential use of electronic tools to improve the delivery of GT under real-world conditions.Considering the hub-and-spoke model, the GTH working group on GT considered the entire patient pathway and reached consensus on requirements for an integrative software tool to secure documenting and sharing information between treaters, pharmacies and patients.Six steps of the gene therapy process were identified, each requiring completion of the previous step as a prerequisite for entry. The responsibilities of GT dosing and follow-up treatment centres, read/write access rules, and the minimum data set were outlined. Data contributed by patients through mobile devices was also considered.Important information needs to be shared between patients and treatment centres in a real-world GT hub-and-spoke model. Collecting and sharing this information in well-organised electronic applications will not only improve patient care but also enable national and international data collection in clinical registries.

The inhibitor of growth family member 4 (ING4) is one of the ING family genes, serves as a repressor of angiogenesis or tumour growth and suppresses loss of contact inhibition. Oncostatin M (OSM) is a multifunctional cytokine that belongs to the interleukin (IL)-6 subfamily with several biological activities. However, the role of recombinant adenoviruses co-expressing ING4 and OSM (Ad-ING4-OSM) in anti-tumour activity of laryngeal cancer has not yet been identified. Recombinant Ad-ING4-OSM was used to evaluate their combined effect on enhanced anti-tumour activity in Hep-2 cells of laryngeal cancer in vivo. Moreover, in vitro function assays of co-expression of Ad-ING4-OSM were performed to explore impact of co-expression of Ad-ING4-OSM on biological phenotype of laryngeal cancer cell line, that is Hep-2 cells. In vitro, Ad-ING4-OSM significantly inhibited the growth, enhanced apoptosis, altered cell cycle with G1 and G2/M phase arrest, and upregulated the expression of P21, P27, P53 and downregulated survivin in laryngeal cancer Hep-2 cells. Furthermore, in vivo functional experiments of co-expressing of Ad-ING4-OSM demonstrated that solid tumours in the nude mouse model were significantly suppressed, and the co-expressing Ad-ING4-OSM showed a significant upregulation expression of P21, P53, Bax and Caspase-3 and a downregulation of Cox-2, Bcl-2 and CD34. This study for the first time demonstrated the clinical value and the role of co-expressing Ad-ING4-OSM in biological function of laryngeal cancer. This work suggested that co-expressing Ad-ING4-OSM might serve as a potential therapeutic target for laryngeal cancer patients.

Colorectal cancer is one of the most common gastrointestinal tumors with good outcomes; however, with distant metastasis, the outcomes are poor. Novel treatment methods are urgently needed. Our in vitro studies indicate that dual-specificity tyrosine-regulated kinase 2 (DYRK2) functions as a tumor suppressor in colorectal cancer by regulating cell survival, proliferation, and apoptosis induction. In addition, DYRK2 expression is decreased in tumor tissues compared to nontumor tissues in colorectal cancer, indicating a correlation with clinical prognosis. In this context, we devised a novel therapeutic strategy to overexpress DYRK2 in tumors by adenovirus-mediated gene transfer. The present study shows that overexpression of DYRK2 in colon cancer cell lines by adenovirus inhibits cell proliferation and induces apoptosis in vitro. Furthermore, in mouse subcutaneous xenograft and liver metastasis models, enforced expression of DYRK2 by direct or intravenous injection of adenovirus to the tumor significantly inhibits tumor growth. Taken together, these findings show that adenovirus-based overexpression of DYRK2 could be a novel gene therapy for liver metastasis of colorectal cancer.

Constitutive activation of STAT3 promotes oncogenesis and growth of oral squamous cell carcinoma (OSCC). We investigated the mechanism of action of suppressor of cytokine signaling 1 (SOCS1), an endogenous inhibitor of JAK, as gene therapy for OSCC.Antitumor effect of SOCS1 was compared to JAK inhibitor I by cell proliferation assay, cell cycle analysis, and apoptosis analysis in vitro. In addition, antitumor effect was evaluated using xenograft mouse models in vivo.JAK inhibitor I inhibited the proliferation of KOSC2 cl3-43 or T3M-1 clone2 OSCC cell lines in vitro. While JAK inhibitor I arrested both cell lines at the G2/M phase, induction of apoptosis was observed in T3M-1 clone2 cells, but not KOSC2-cl3-43 cells. An adenoviral vector expressing SOCS1 (AdSOCS1) significantly decreased the proliferation of both OSCC cell lines and induced G2/M phase cell cycle arrest and apoptosis, suggesting that induction of apoptosis of KOSC2 cl3-43 cells by AdSOCS1 is regulated by the JAK/STAT independent pathway. Overexpression of SOCS1 inhibited activation of the JAK/STAT and p44/42 MAPK pathways, while JAK inhibitor I inhibited activation of the JAK/STAT pathway only. Consistently, expression of Mcl-1 was decreased by overexpression of SOCS1, but not JAK inhibitor I. Additionally, KOSC2 cl3-43 or T3M-1 clone2 OSCC cells were subcutaneously implanted in the flanks of two xenograft mouse models. As compared to a control adenovirus vector (AdLacZ), intratumor injection of AdSOCS1 significantly decreased the tumor volume and induced apoptosis in vivo.SOCS1 gene therapy may be a beneficial approach for the treatment of OSCC.

Breast cancer (BC) is the most prevalent malignancy and the second leading cause of death among women worldwide that is caused by numerous genetic and environmental factors. Hence, effective treatment for this type of cancer requires new therapeutic approaches. The traditional methods for treating this cancer have side effects, therefore so much research have been performed in last decade to find new methods to alleviate these problems. The study of the molecular basis of breast cancer has led to the introduction of gene therapy as an effective therapeutic approach for this cancer. Gene therapy involves sending genetic material through a vector into target cells, which is followed by a correction, addition, or suppression of the gene. In this technique, it is necessary to target tumour cells without affecting normal cells. In addition, clinical trial studies have shown that this approach is less toxic than traditional therapies. This study will review various aspects of breast cancer, gene therapy strategies, limitations, challenges and recent studies in this area.

As one of the gene therapies, RNA interference (RNAi) effectively suppresses only specific genes, targeting various diseases in which they are involved. For the successful process of RNAi, efficient and safe delivery of small RNAs, including small interfering RNA and short hairpin RNA, is essential. Herein, an S-R11 fusion peptide, SPACE peptide conjugated with poly-arginine, was introduced to deliver small RNAs into immune cells that are difficult to transfect. This S-R11 peptide stably formed a spontaneous self-assembling nanocomplex through electrostatic attraction and hydrogen bonding with small RNAs. The nanocomplex showed about 5.3-fold better permeation efficiency than the conventional Lipofectamine™ 2000 for RAW 264.7 macrophage cells. Moreover, it induced about 66.2% silencing effect of the target gene in the cells activated with polyinosinic:polycytidylic acid (poly (I:C)). In addition, the cell viability of fusion peptide was ensured even in a concentration range exceeding the concentration used in the nanocomplex. Based on these results, it is expected that the nanocomplex in this study can be used as a new gene delivery system that can overcome the challenge of gene therapies to immune cells.

Barth Syndrome is an X-linked disorder of mitochondrial cardiolipin metabolism caused by pathogenic variants in TAFAZZIN with pleiotropic effects including cardiomyopathy, neutropenia, growth delay, and skeletal myopathy. Management requires a multidisciplinary approach to the organ-specific manifestations including specialists from cardiology, hematology, nutrition, physical therapy, genetics, and metabolism. Currently, treatment is centered on management of specific clinical features, and is not targeted towards remediating the underlying biochemical defect. However, two clinical trials have been recently undertaken which target the mitochondrial pathology of this disease: a study to examine the effects of elamipretide, a cardiolipin targeted agent, and a study to examine the effects of bezafibrate, a peroxisome proliferator-activated receptor (PPAR) agonist. Treatments to directly target the defective TAFAZZIN pathway are under development, including enzyme and gene therapies. This article is protected by copyright. All rights reserved.

Experimental cell models are indispensable for clarifying the pathophysiology of coronavirus disease 2019 (COVID‐19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection, and for developing therapeutic agents. To recapitulate the symptoms and drug response of COVID‐19 patients in vitro, SARS‐CoV‐2 studies using physiologically relevant human embryonic stem (ES)/induced pluripotent stem (iPS) cell‐derived somatic cells and organoids are ongoing. These cells and organoids have been used to show that SARS‐CoV‐2 can infect and damage various organs including the lung, heart, brain, intestinal tract, kidney, and pancreas. They are also being used to develop COVID‐19 therapeutic agents, including evaluation of their antiviral efficacy and safety. The relationship between COVID‐19 aggravation and human genetic backgrounds has been investigated using genetically modified ES/iPS cells and patient‐derived iPS cells. This review summarizes the latest results and issues of SARS‐CoV‐2 research using human ES/iPS cell‐derived somatic cells and organoids., To recapitulate the symptoms and drug response of COVID‐19 patients in vitro, SARS‐CoV‐2 studies using physiologically relevant human embryonic stem/induced pluripotent stem cell‐derived somatic cells and organoids are ongoing. They are being used to investigate SARS‐CoV‐2 cell tropism, to develop COVID‐19 therapeutic agents, and to examine the relationship between COVID‐19 aggravation and human genetic backgrounds.

Cystathionine β-synthase (CBS) deficiency is a recessive inborn error of sulfur metabolism characterized by elevated blood levels of total homocysteine (tHcy). Patients diagnosed with CBS deficiency are currently treated by a combination of vitamin supplementation and restriction of foods containing the homocysteine precursor methionine, but the effectiveness of this therapy is limited due to poor compliance. A mouse model for CBS deficiency (Tg-I278T Cbs-/- ) was used to evaluate a potential gene therapy approach to treat CBS deficiency utilizing an AAVrh.10-based vector containing the human CBS cDNA downstream of the constitutive, strong CAG promoter (AAVrh.10hCBS). Mice were administered a single dose of virus and followed for up to one year. The data demonstrated a dose-dependent increase in liver CBS activity and a dose-dependent decrease in serum tHcy. Liver CBS enzyme activity at one year was similar to Cbs+/- control mice. Mice given the highest dose (5.6x1011 genomes/mouse) had mean serum tHcy decrease of 97% one week after injection and an 81% reduction one year after injection. Treated mice had either full- or substantial correction of alopecia, bone loss, and fat mass phenotypes associated with Cbs deficiency in mice. Our findings show that AAVrh.10-based gene therapy is highly effective in treating CBS deficiency in mice and supports additional pre-clinical testing for eventual use human trials. This article is protected by copyright. All rights reserved.

Polyglutamine spinocerebellar ataxias (SCAs) comprise a heterogeneous group of six autosomal dominant ataxias caused by cytosine-adenine-guanine repeat expansions in the coding region of single genes. Currently, there is no curative or disease-slowing treatment for these disorders, but their monogenic inheritance has informed rationales for development of gene therapy strategies. In fact, RNA interference strategies have shown promising findings in cellular and/or animal models of SCA1, SCA3, SCA6, and SCA7. In addition, antisense oligonucleotide therapy has provided encouraging proofs of concept in models of SCA1, SCA2, SCA3, and SCA7, but they have not yet progressed to clinical trials. On the contrary, the gene editing strategies, such as the clustered regularly interspaced short palindromic repeat (CRISPR/Cas9), have been introduced to a limited extent in these disorders. In this article, we review the available literature about gene therapy in polyglutamine SCAs and discuss the main technological and ethical challenges toward the prospect of their use in future clinical trials. Although antisense oligonucleotide therapies are further along the path to clinical phases, the recent failure of three clinical trials in Huntington's disease may delay their utilization for polyglutamine SCAs, but they offer lessons that could optimize the likelihood of success in potential future clinical studies. © 2021 International Parkinson and Movement Disorder Society.

Biallelic mutations in the RCBTB1 gene cause retinal dystrophy. Here, we characterized the effects of RCBTB1 gene deficiency in retinal pigment epithelial (RPE) cells derived from a patient with RCBTB1‐associated retinopathy and restored RCBTB1 expression in these cells using adeno‐associated viral (AAV) vectors. Induced pluripotent stem cells derived from a patient with compound heterozygous RCBTB1 mutations (c.170delG and c.707delA) and healthy control subjects were differentiated into RPE cells. RPE cells were treated with AAV vectors carrying a RCBTB1 transgene. Patient‐derived RPE cells showed reduced expression of RCBTB1. Expression of NFE2L2 showed a non‐significant reduction in patient RPE cells compared with controls, while expression of its target genes (RXRA, IDH1 and SLC25A25) was significantly reduced. Trans‐epithelial electrical resistance, surface microvillus densities and primary cilium lengths were reduced in patient‐derived RPE cells, compared with controls. Treatment of patient RPE with AAV vectors significantly increased RCBTB1, NFE2L2 and RXRA expression and cilium lengths. Our study provides the first report examining the phenotype of RPE cells derived from a patient with RCBTB1‐associated retinopathy. Furthermore, treatment of patient‐derived RPE with AAV‐RCBTB1 vectors corrected deficits in gene expression and RPE ultrastructure, supporting the use of gene replacement therapy for treating this inherited retinal disease.

Recombinant adeno-associated virus (AAV) is currently the most widely used platform for in vivo gene therapy. Clinical pharmacology is a central field for AAV gene therapy, represented by the pillars of pharmacokinetics, pharmacodynamics/efficacy, and safety. In this review, we provide a comprehensive summary of clinical pharmacology considerations for recombinant AAV. The main topics covered are biodistribution and shedding, dose-exposure-response relationship, safety, immune and stress response, and clinical dose selection strategies. We highlight how the cumulative knowledge of AAV gene therapy could help with guiding clinical trial design and assessing and mitigating risks, as well as planning and executing pharmacokinetic/pharmacodynamic /safety data analyses. In addition, we discuss the major gaps and areas of growth in clinical pharmacology understanding of recombinant AAV. These include the mechanisms of the durability of treatment response and variability in biodistribution, transduction, and immunogenicity, as well as a potential influence on AAV's safety and efficacy profiles by drug product characteristics and patient intrinsic/extrinsic factors.

Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disorder characterized by α-L-iduronidase deficiency. Patients present with a broad spectrum of disease severity ranging from the most severe phenotype (Hurler) with devastating neurocognitive decline, bone disease and early death to intermediate (Hurler-Scheie) and more attenuated (Scheie) phenotypes, with a normal life expectancy. The most severely affected patients are preferably treated with haematopoietic stem cell transplantation, which halts the neurocognitive decline. Patients with more attenuated phenotypes are treated with enzyme replacement therapy. There are several challenges to be met in the treatment of MPS I patients. Firstly, to optimize outcome, early recognition of the disease and clinical phenotype is needed to guide decisions on therapeutic strategies. Secondly, there is thus far no effective treatment available for MPS I bone disease. The pathophysiological mechanisms behind bone disease are largely unknown, limiting the development of effective therapeutic strategies. This article is a state of the art that comprehensively discusses 3 of the most urgent open issues in MPS I: early diagnosis of MPS I patients, pathophysiology of MPS I bone disease, and emerging therapeutic strategies for MPS I bone disease. This article is protected by copyright. All rights reserved.

Phenylketonuria (PKU) is the most common inborn error of metabolism of the liver, and results from mutations of both alleles of the phenylalanine hydroxylase gene (PAH). As such, it is a suitable target for gene therapy via gene delivery with a recombinant adeno-associated virus (AAV) vector. Here we use the synthetic AAV vector Anc80 via systemic administration to deliver a functional copy of a codon-optimized human PAH gene, with or without an intron spacer, to the Pahenu2 mouse model of PKU. Dose-dependent transduction of the liver and expression of PAH mRNA were present with both vectors, resulting in significant and durable reduction of circulating phenylalanine, reaching near control levels in males. Coat color of treated Pahenu2 mice reflected an increase in pigmentation from brown to the black color of control animals, further indicating functional restoration of phenylalanine metabolism and its byproduct melanin. There were no adverse effects associated with administration of AAV up to 5 × 1012 VG/kg, the highest dose tested. Only minor and/or transient variations in some liver enzymes were observed in some of the AAV-dosed animals which were not associated with pathology findings in the liver. Finally, there was no impact on cell turnover or apoptosis as evaluated by Ki-67 and TUNEL staining, further supporting the safety of this approach. This study demonstrates the therapeutic potential of AAV Anc80 to safely and durably cure PKU in a mouse model, supporting development for clinical consideration.

Introduction/aims There are currently three medications approved for spinal muscular atrophy (SMA), but the use of these medications in combination has not been well described. Methods This is a retrospective report of four cases of SMA treated with dual onasemnogene and risdiplam therapy at our institution. Results Following onasemnogene therapy, all four patients experienced a perceived plateau of therapeutic benefit, at which time daily risdiplam was started. Transient fatigue and weakness was seen in two patients following risdiplam initiation, but this resolved within 1 mo. One patient was hospitalized with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and post-viral pneumonia, weeks following risdiplam initiation. No other adverse effects related to onasemnogene and risdiplam combination therapy were identified and all patients experienced objective and subjective improvement. Discussion Combination therapy with onasemnogene and risdiplam in patients with SMA appears to be well-tolerated. Further large prospective trials are needed to determine whether dual therapy is more efficacious than monotherapy, and to identify rare adverse events that may occur with the use of combination therapy.

This study was aimed at investigating whether Elabela (ELA) gene therapy can promote angiogenesis in the treatment of myocardial infarction (MI). The fusion expression plasmid pAAV‐3 × Flag/ELA‐32 was successfully constructed using molecular cloning technique. The model of acute MI was established by ligating the left anterior descending coronary artery in mice. Adeno‐associated virus serotype 9 (AAV9) was injected into the surrounding myocardium and tail vein immediately after the model was established. AAV was injected again from the tail vein one week later. Compared with the MI+PBS (control) group, the serum N‐terminal pro‐brain natriuretic peptide (NT‐proBNP) concentration, and the values of left ventricular end‐diastolic diameter (LVDd) and left ventricular end‐systolic diameter (LVDs) of the MI+AAV‐ELA (gene therapy) group were significantly decreased, while the value of left ventricular ejection fraction was significantly increased at 2 and 4 weeks after operation. Compared with the control group, the expression of CD105 and vWF and the percentage of CD31‐ and Ki67–co‐positive cells were significantly increased in the gene therapy group. Moreover, the expressions of apelin peptide jejunum (APJ) receptor, vascular endothelial growth factor (VEGF), VEGFR2, Jagged1 and Notch3 in the heart tissue around the infarction were up‐regulated in mice with gene therapy. The results suggest that ELA activates VEFG/VEGFR2 and Jagged1/Notch3 pathways through APJ to promote angiogenesis after myocardial infarction. ELA gene therapy may be used in the treatment of ischaemic cardiomyopathy in future.

Spinal muscular atrophy (SMA) is an autosomal recessive, neurodegenerative disease caused by biallelic mutations in the survival motor neuron 1 (SMN1) gene. SMA is characterized by motor neuron degeneration, resulting in progressive muscle atrophy and weakness. Before the emergence of disease‐modifying therapies, children with the most severe form of SMA would never achieve the ability to sit independently. Only 8% survived beyond 20 months of age without permanent ventilator support. One such therapy, onasemnogene abeparvovec, an adeno‐associated virus–based gene replacement therapy, delivers functional human SMN through a one‐time intravenous infusion. In addition to substantially improving survival, onasemnogene abeparvovec was found to increase motor milestone attainment and reduce the need for respiratory or nutritional support in many patients. This expert opinion provides recommendations and practical considerations on the patient‐centered decisions to use onasemnogene abeparvovec. Recommendations include the need for patient‐centered multidisciplinary care and patient selection to identify those with underlying medical conditions or active infections to reduce risks. We also describe the importance of retesting patients with elevated anti–adeno‐associated virus serotype 9 antibodies. Recommendations for prednisolone tapering and monitoring for potential adverse events, including hepatotoxicity and thrombotic microangiopathy, are described. The need for caregiver education on managing day‐to‐day care at time of treatment and patient‐ and family‐centered discussions on realistic expectations are also recommended. We detail the importance of following standard‐of‐care guidance and long‐term monitoring of all children with SMA who have received one or more disease‐modifying therapy using registries. We also highlight the need for presymptomatic or early symptomatic treatment of this disorder.

Recent advances have facilitated studies of the clonal architecture of the aging haematopoietic system, and provided clues to the mechanisms underlying the origins of hematopoietic malignancy. Much less is known about the clonal composition of haematopoiesis and its impact in bone marrow failure (BMF) disorders, including Fanconi anaemia (FA). Understanding clonality in FA is likely to inform both the marked predisposition to cancer and the rapid erosion of regenerative reserve seen with this disease. This may also hold broader lessons for haematopoietic stem cell biology in other diseases with a clonal restriction. In this review, we focus on the conceptual basis and available tools to study clonality, and highlight insights in somatic mosaicism and malignant evolution in FA in the context of haematopoietic failure and gene therapy.

Central Nervous System (CNS) diseases, such as Alzheimer's diseases (AD), Parkinson's Diseases (PD), brain tumors, Huntington's disease (HD), and stroke, still remain difficult to treat by the conventional molecular drugs. In recent years, various gene therapies have come into the spotlight as versatile therapeutics providing the potential to prevent and treat these diseases. Despite the significant progress that has undoubtedly been achieved in terms of the design and modification of genetic modulators with desired potency and minimized unwanted immune responses, the efficient and safe in vivo delivery of gene therapies still poses major translational challenges. Various non-viral nanomedicines have been recently explored to circumvent this limitation. In this review, an overview of gene therapies for CNS diseases is provided and describes recent advances in the development of nanomedicines, including their unique characteristics, chemical modifications, bioconjugations, and the specific applications that those nanomedicines are harnessed to deliver gene therapies.

Emerging evidence indicates the early growth response 1 (Egr1) plays an important role in the pathogenesis of chronic pain. However, the regulation of Egr1 expression in the DRG and spinal cord in neuropathic pain remains unclear. In the current study, the neuropathic pain was conducted by lumber 5 spinal nerve ligation (SNL) in rats. The role of miR-124-3p in Egr1 expression was examined. Our results showed that the SNL led to a significant increase in the expression of Egr1 mRNA and protein in the DRG and dorsal horn. This increased expression of Egr1 correlated with a reduction of miR-124-3p in the same region. Prior i.t. injection of Egr1 decoy AYX1 inhibited the expression of Egr1 and attenuated the neuropathic pain-like hypersensitivity following SNL. The dual-luciferase reporter assay revealed the luciferase activity of the Egr1 3'-UTR plasmid was inhibited by the miR-124-3p agomir. But this inhibition was completely reversed in the mutant 3'-UTR Egr1 group. In vivo, the SNL-induced behavioral signs of neuropathic pain and the increases in Egr1 mRNA and protein in the DRG and dorsal horn were prevented by prior to i.t. injection of miR-124-3p agomir. While, i.t. injection of miR-124-3p antagomir in naïve rats resulted in mechanical allodynia and thermal hyperalgesia and an overexpression of Egr1 in the DRG and dorsal horn. Together, our results suggest that the miR-124-3p-regulated Egr1 expression in the DRG and dorsal horn contributes to the development of neuropathic pain. Targeting miR-124-3p might be a promising therapeutic strategy in the treatment of chronic pain.

We developed a mathematical model for autologous stem cell therapy to cure sickle cell disease (SCD). Experimental therapies using this approach seek to engraft stem cells containing a curative gene. These stem cells are expected to produce a lifelong supply of red blood cells (RBCs) containing an anti‐sickling hemoglobin. This complex, multistep treatment is expensive, and there is limited patient data available from early clinical trials. Our objective was to quantify the impact of treatment parameters, such as initial stem cell dose, efficiency of lentiviral transduction, and degree of bone marrow preconditioning on engraftment efficiency, peripheral RBC numbers, and anti‐sickling hemoglobin levels over time. We used ordinary differential equations to model RBC production from progenitor cells in the bone marrow, and hemoglobin assembly from its constituent globin monomers. The model recapitulates observed RBC and hemoglobin levels in healthy and SCD phenotypes. Treatment simulations predict dynamics of stem cell engraftment and RBC containing the therapeutic gene product. Post‐treatment dynamics show an early phase of reconstitution due to short lived stem cells, followed by a sustained RBC production from stable engraftment of long‐term stem cells. This biphasic behavior was previously reported in the literature. Sensitivity analysis of the model quantified relationships between treatment parameters and efficacy. The initial dose of transduced stem cells, and the intensity of myeloablative bone marrow preconditioning are predicted to most positively impact long‐term outcomes. The quantitative systems pharmacology approach used here demonstrates the value of model‐assisted therapeutic design for gene therapies in SCD.

Hypophosphatasia (HPP) is caused by loss‐of‐function mutations in the ALPL gene that encodes tissue‐nonspecific alkaline phosphatase (TNAP), whose deficiency results in the accumulation of extracellular inorganic pyrophosphate (PPi), a potent mineralization inhibitor. Skeletal and dental hypomineralization characterizes HPP, with disease severity varying from life‐threatening perinatal or infantile forms to milder forms that manifest in adulthood or only affect the dentition. Enzyme replacement therapy (ERT) using mineral‐targeted recombinant TNAP (Strensiq/asfotase alfa) markedly improves the life span, skeletal phenotype, motor function, and quality of life of patients with HPP, though limitations of ERT include frequent injections due to a short elimination half‐life of 2.28 days and injection site reactions. We tested the efficacy of a single intramuscular administration of adeno‐associated virus 8 (AAV8) encoding TNAP‐D10 to increase the life span and improve the skeletal and dentoalveolar phenotypes in TNAP knockout (Alpl −/−) mice, a murine model for severe infantile HPP. Alpl −/− mice received 3 × 1011 vector genomes/body of AAV8‐TNAP‐D10 within 5 days postnatal (dpn). AAV8‐TNAP‐D10 elevated serum ALP activity and suppressed plasma PPi. Treatment extended life span of Alpl −/− mice, and no ectopic calcifications were observed in the kidneys, aorta, coronary arteries, or brain in the 70 dpn observational window. Treated Alpl −/− mice did not show signs of rickets, including bowing of long bones, enlargement of epiphyses, or fractures. Bone microstructure of treated Alpl −/− mice was similar to wild type, with a few persistent small cortical and trabecular defects. Histology showed no measurable osteoid accumulation but reduced bone volume fraction in treated Alpl −/− mice versus controls. Treated Alpl −/− mice featured normal molar and incisor dentoalveolar tissues, with the exceptions of slightly reduced molar enamel and alveolar bone density. Histology showed the presence of cementum and normal periodontal ligament attachment. These results support gene therapy as a promising alternative to ERT for the treatment of HPP. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Fanconi anemia (FA) is characterized by chromosome fragility, bone marrow failure (BMF) and predisposition to cancer. As reverse genetic mosaicism has been described as "natural gene therapy" in patients with FA, we sought to evaluate the clinical course of a cohort of FA mosaic patients followed at referral centers in Spain over a 30-year period. This cohort includes patients with a majority of T cells without chromosomal aberrations in the DEB-chromosomal breakage test. Relative to non-mosaic FA patients, we observed a higher proportion of adult patients in the cohort of mosaics, with a later age of hematologic onset and a milder evolution of (BMF). Consequently, the requirement for hematopoietic stem cell transplant (HSCT) was also lower. Additional studies allowed us to identify a sub-cohort of mosaic FA patients in whom the reversion was present in bone marrow (BM) progenitor cells leading to multilineage mosaicism. These multilineage mosaic patients are older, have a lower percentage of aberrant cells, have more stable hematology and none of them developed leukemia or myelodysplastic syndrome when compared to non-mosaics. In conclusion, our data indicate that reverse mosaicism is a good prognostic factor in FA and is associated with more favorable long-term clinical outcomes.

Prostate cancer is one of the predominant cancers affecting men and has been widely reported. In the past, various therapies and drugs have been proposed to treat prostate cancer. Among these treatments, gene therapy has been considered to be an optimal and widely applicable treatment. Furthermore, due to the increased specificity of gene sequence complementation, the targeted delivery of complementary gene sequences may represent a useful treatment in certain instances. Various gene therapies, including tumor-suppressor gene therapy, suicide gene therapy, immunomodulation gene therapy and anti-oncogene therapies, have been established to treat a wide range of diseases, such as cardiac disease, cystic fibrosis, HIV/AIDS, diabetes, hemophilia, and cancers. To this end, several gene therapy clinical trials at various phases are underway. This overview describes the developments and progress in gene therapy, with a special focus being placed on prostate cancer.