Ethical and regulatory aspects of genome editing

The paths toward non-viral CAR-T cell manufacturing: A comprehensive review of state-of-the-art methods

Although CAR-T cell therapy has emerged as a game-changer in cancer immunotherapy several bottlenecks limit its widespread use as a front-line therapy. Current protocols for the production of CAR-T cells rely mainly on the use of lentiviral/retroviral vectors. Nevertheless, according to the safety concerns around the use of viral vectors, there are several regulatory hurdles to their clinical use. Large-scale production of viral vectors under "Current Good Manufacturing Practice" (cGMP) involves rigorous quality control assessments and regulatory requirements that impose exorbitant costs on suppliers and as a result, lead to a significant increase in the cost of treatment. Pursuing an efficient non-viral method for genetic modification of immune cells is a hot topic in cell-based gene therapy. This study aims to investigate the current state-of-the-art in non-viral methods of CAR-T cell manufacturing. In the first part of this study, after reviewing the advantages and disadvantages of the clinical use of viral vectors, different non-viral vectors and the path of their clinical translation are discussed. These vectors include transposons (sleeping beauty, piggyBac, Tol2, and Tc Buster), programmable nucleases (ZFNs, TALENs, and CRISPR/Cas9), mRNA, plasmids, minicircles, and nanoplasmids. Afterward, various methods for efficient delivery of non-viral vectors into the cells are reviewed.

Harnessing the potential of hydrogels for advanced therapeutic applications: current achievements and future directions

The applications of hydrogels have expanded significantly due to their versatile, highly tunable properties and breakthroughs in biomaterial technologies. In this review, we cover the major achievements and the potential of hydrogels in therapeutic applications, focusing primarily on two areas: emerging cell-based therapies and promising non-cell therapeutic modalities. Within the context of cell therapy, we discuss the capacity of hydrogels to overcome the existing translational challenges faced by mainstream cell therapy paradigms, provide a detailed discussion on the advantages and principal design considerations of hydrogels for boosting the efficacy of cell therapy, as well as list specific examples of their applications in different disease scenarios. We then explore the potential of hydrogels in drug delivery, physical intervention therapies, and other non-cell therapeutic areas (e.g., bioadhesives, artificial tissues, and biosensors), emphasizing their utility beyond mere delivery vehicles. Additionally, we complement our discussion on the latest progress and challenges in the clinical application of hydrogels and outline future research directions, particularly in terms of integration with advanced biomanufacturing technologies. This review aims to present a comprehensive view and critical insights into the design and selection of hydrogels for both cell therapy and non-cell therapies, tailored to meet the therapeutic requirements of diverse diseases and situations.

Advancing Precision Medicine with Gene and Cell Therapy in Malaysia: Ethical, Legal, and Social Implications

A new era of gene and cell therapy for treating human diseases has been envisioned for several decades. However, given that the technology can alter any DNA/cell in human beings, it poses specific ethical, legal, and social difficulties in its application. In Malaysia, current bioethics and medical ethics guidelines tackle clinical trials and biomedical research, medical genetic services, and stem cell research/therapy. However, no comprehensive framework and policy is available to cater to ethical gene and cell therapy in the country. Incorporating ethical, legal, and social implications (ELSI) would be crucial to guide the appropriate use of human gene and cell therapy in conjunction with precision medicine. Policy experts, scientists, bioethicists, and public members must debate the associated ELSI and the professional code of conduct while preserving human rights.

Advances in Genetic Editing of the Human Embryo

BACKGROUND

Genetic engineering has allowed a major development of research in this field, with specialists attempting to edit the human genome, after the successful editing of the genomes of plants and animals. However, human gene editing technologies are at the center of ethical debates around the world.

AREAS OF UNCERTAINTY

Ethical concerns about genetic editing of the human embryo raise several issues that can be viewed through the prism of optimism and reluctance leading to a number of recommendations regarding the acceptance of what may soon become a reality.

DATA SOURCES

A literature search was conducted through PubMed, MEDLINE, Plus, Scopus, and Web of Science (2015-2022) using combinations of keywords, including: human genome or gene editing plus ethics.

ETHICS AND THERAPEUTIC ADVANCES

Gene therapy is seen by researchers as a way to solve congenital diseases, multifactorial diseases in general or specific diseases such as cystic fibrosis, muscular dystrophy, or can increase resistance to HIV infection. Genome editing technologies, germline gene editing, clustered regularly interspaced short palindromic repeats gene editing technology, technologies such as zinc finger nucleases are not only advanced gene therapies that require solving technical problems, but also techniques that require complex and complete analysis of ethical problems. Genetic engineering raises many ethical concerns such as: safety concerns especially the risk of off-target effects; autonomy of the individual-with the limitation of the future generations to consent for an intervention over their genome; social justice-keeping in mind the costs of the procedures and their availability to the general population. Discussions can go further from questions such as "How can we do this?" to questions such as "Should we do this?" or "Is society ready to accept this technology and is it able to manage it rationally?"

CONCLUSIONS

The ethics of biomedical research should be based on global dialogue, on the involvement of experts and the public, to achieve a broad social consensus. The fundamental review of the ethics of genetics is a desire and an opportunity of the current period.

Gene editing strategies to treat lysosomal disorders: The example of mucopolysaccharidoses

Lysosomal storage disorders are a group of progressive multisystemic hereditary diseases with a combined incidence of 1:4,800. Here we review the clinical and molecular characteristics of these diseases, with a special focus on Mucopolysaccharidoses, caused primarily by the lysosomal storage of glycosaminoglycans. Different gene editing techniques can be used to ameliorate their symptoms, using both viral and nonviral delivery methods. Whereas these are still being tested in animal models, early results of phase I/II clinical trials of gene therapy show how this technology may impact the future treatment of these diseases. Hurdles related to specific hard-to-reach organs, such as the central nervous system, heart, joints, and the eye must be tackled. Finally, the regulatory framework necessary to advance into clinical practice is also discussed.

From Descriptive to Functional Genomics of Leukemias Focusing on Genome Engineering Techniques

Genome engineering makes the precise manipulation of DNA sequences possible in a cell. Therefore, it is essential for understanding gene function. Meganucleases were the start of genome engineering, and it continued with the discovery of Zinc finger nucleases (ZFNs), followed by Transcription activator-like effector nucleases (TALENs). They can generate double-strand breaks at a desired target site in the genome, and therefore can be used to knock in mutations or knock out genes in the same way. Years later, genome engineering was transformed by the discovery of clustered regularly interspaced short palindromic repeats (CRISPR). Implementation of CRISPR systems involves recognition guided by RNA and the precise cleaving of DNA molecules. This property proves its utility in epigenetics and genome engineering. CRISPR has been and is being continuously successfully used to model mutations in leukemic cell lines and control gene expression. Furthermore, it is used to identify targets and discover drugs for immune therapies. The descriptive and functional genomics of leukemias is discussed in this study, with an emphasis on genome engineering methods. The CRISPR/Cas9 system's challenges, viewpoints, limits, and solutions are also explored.

Mini review: genome and transcriptome editing using CRISPR-cas systems for haematological malignancy gene therapy

The recent introduction of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR associated protein (Cas) systems, offer an array of genome and transcriptome editing tools for clinical repair strategies. These include Cas9, Cas12a, dCas9 and more recently Cas13 effectors. RNA targeting CRISPR-Cas13 complexes show unique characteristics with the capability to engineer transcriptomes and modify gene expression, providing a potential clinical cancer therapy tool across various tissue types. Cas13 effectors such as RNA base editing for A to I replacement allows for precise transcript modification. Further applications of Cas13a highlights its capability of producing rapid diagnostic results in a mobile platform. This review will focus on the adaptions of existing CRISPR-Cas systems, along with new Cas effectors for transcriptome or RNA modifications used in disease modelling and gene therapy for haematological malignancy. We also address the current diagnostic and therapeutic potential of CRISPR-Cas systems for personalised haematological malignancy.

Lysosomal storage diseases: current therapies and future alternatives

Lysosomal storage disorders (LSDs) are a group of monogenic diseases characterized by progressive accumulation of undegraded substrates into the lysosome, due to mutations in genes that encode for proteins involved in normal lysosomal function. In recent years, several approaches have been explored to find effective and successful therapies, including enzyme replacement therapy, substrate reduction therapy, pharmacological chaperones, hematopoietic stem cell transplantation, and gene therapy. In the case of gene therapy, genome editing technologies have opened new horizons to accelerate the development of novel treatment alternatives for LSD patients. In this review, we discuss the current therapies for this group of disorders and present a detailed description of major genome editing technologies, as well as the most recent advances in the treatment of LSDs. We will further highlight the challenges and current bioethical debates of genome editing.

Advanced therapy medicinal products: value judgement and ethical evaluation in health technology assessment

Advanced therapy medicinal products (ATMPs) are a heterogeneous class of medicinal products that by offering the potential of cure represent a paradigm shift in the approach of many life-threatening diseases. Although a common regulatory framework for ATMPs has been established in the EU, the health technology assessment (HTA) and financing decisions remain local. The aim of this article is to present an integrated analysis of the current status of the value judgment of ATMPs and the integration of ethical evaluation in the HTA process. It has been identified that approaching the specificities of ATMPs in terms of market access will require a broadening of the definition of value to be able to systematically capture elements of value not traditionally considered. Outcomes modelling will play an important role in the pricing and reimbursement of ATMPs, providing a way to bridge the gap caused by the absence of data from clinical studies or real-world data. Given the nature and disruptive consequences of ATMPs the assessment and adoption of these medicinal products raises important ethical questions, both at a policy and at society level that should be properly addressed. HTA can be made more transparent and reliable, and simultaneously promote robust and accountable decision making, by turning explicit the value judgments implicit in HTA. Ultimately, there should be no core conflict between ethical requirements and HTA in a scenario where the goal is to promote equity and access of patients to truly innovative therapies such as ATMPs, while assuring the sustainability of healthcare systems.

Efficient Gene Disruption via Base Editing Induced Stop in Newt Pleurodeles waltl

Loss-of-function approaches provide strong evidence for determining the role of particular genes. The prevalent CRISPR/Cas9 technique is widely used to disrupt target gene with uncontrolled non-homologous end joining after the double strand breaks, which results in mosaicism and multiple genotypes in the founders. In animal models with long generation time such as the salamanders, producing homozygous offspring mutants would be rather labor intensive and time consuming. Here we utilized the base editing technique to create the loss-of-function F0 mutants without the random indels. As a proof of principle, we successfully introduced premature stop codons into the tyrosinase locus and produced the albino phenotype in the newts (Pleurodeles waltl). We further demonstrated that the knockout efficiency could be greatly improved by using multiplex sgRNAs target the same gene. The F0 mutated animals showed fully loss-of-function by both genotyping and phenotyping analysis, which could enable direct functional analysis in the founders and avoid sophisticated breeding. This study not only presented the high efficiency of single base editing in a gigantic animal genome (>20 G), but also provided new tools for interrogating gene function in other salamander species.

Questions Answered and Unanswered by the First CRISPR Editing Study in a Canine Model of Duchenne Muscular Dystrophy

Clustered regularly interspaced short palindromic repeats (CRISPR) editing is being considered as a potential gene repair therapy to treat Duchenne muscular dystrophy, a dystrophin-deficient lethal muscle disease affecting all muscles in the body. A recent preliminary study from the Olson laboratory (Amoasii et al. Science 2018;362:89-91) showed robust dystrophin restoration in a canine Duchenne muscular dystrophy model following intramuscular or intravenous delivery of the CRISPR editing machinery by adeno-associated virus serotype 9. Despite the limitation of the small sample size, short study duration, and the lack of muscle function data, the Olson lab findings have provided important proof of principle for scaling up CRISPR therapy from rodents to large mammals. Future large-scale, long-term, and comprehensive studies are warranted to establish the safety and efficacy of CRISPR editing therapy in large mammals.

CRISPR to fix bad blood: a new tool in basic and clinical hematology

Advances in genome engineering in the last decade, particularly in the development of programmable nucleases, have made it possible to edit the genomes of most cell types precisely and efficiently. Chief among these advances, the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system is a novel, versatile and easy-to-use tool to edit genomes irrespective of their complexity, with multiple and broad applications in biomedicine. In this review, we focus on the use of CRISPR/Cas9 genome editing in the context of hematologic diseases and appraise the major achievements and challenges in this rapidly moving field to gain a clearer perspective on the potential of this technology to move from the laboratory to the clinic. Accordingly, we discuss data from studies editing hematopoietic cells to understand and model blood diseases, and to develop novel therapies for hematologic malignancies. We provide an overview of the applications of gene editing in experimental, preclinical and clinical hematology including interrogation of gene function, target identification and drug discovery and chimeric antigen receptor T-cell engineering. We also highlight current limitations of CRISPR/Cas9 and the possible strategies to overcome them. Finally, we consider what advances in CRISPR/Cas9 are needed to move the hematology field forward.

Ethics of Human Genome Editing

Advances in human genome editing, in particular the development of the clustered regularly interspaced palindromic repeats (CRISPR)/Cas9 method, have led to increasing concerns about the ethics of editing the human genome. In response, the US National Academy of Sciences and the National Academy of Medicine constituted a multidisciplinary, international committee to review the current status and make recommendations. I was a member of that committee, and the core of this review reflects the committee's conclusions. The committee's report, issued in February 2017, recommends the application of current ethical and regulatory standards for gene therapy to somatic (nonheritable) human genome editing. It also recommends allowing experimental germline genome editing to proceed if ( a) it is restricted to preventing transmission of a serious disease or condition, ( b) the edit is a modification to a common DNA sequence known not to be associated with disease, and ( c) the research is conducted under a stringent set of ethical and regulatory requirements. Crossing the so-called red line of germline genome editing raises important bioethical issues, most importantly, serious concern about the potential negative impact on individuals with disabilities. This review highlights some of the major ethical considerations in human genome editing in light of the report's recommendations.

Interferons and beyond: Induction of antiretroviral restriction factors

Antiviral restriction factors are structurally and functionally diverse cellular proteins that play a key role in the first line of defense against viral pathogens. Although many cell types constitutively express restriction factors at low levels, their induction in response to viral exposure and replication is often required for potent control and repulse of the invading pathogens. It is well established that type I IFNs efficiently induce antiviral restriction factors. Accumulating evidence suggests that other types of IFN, as well as specific cytokines, such as IL-27, and other activators of the cell are also capable of enhancing the expression of restriction factors and hence to establish an antiviral cellular state. Agents that efficiently induce restriction factors, increase their activity, and/or render them resistant against viral antagonists without causing general inflammation and significant side effects hold some promise for novel therapeutic or preventive strategies. In the present review, we summarize some of the current knowledge on the induction of antiretroviral restriction factors and perspectives for therapeutic application.

Gene Therapy Approaches to Human Immunodeficiency Virus and Other Infectious Diseases

Advances in gene therapy technologies, particularly in gene editing, are suggesting new avenues for the treatment of human immunodeficiency virus and other infectious diseases. This article outlines recent developments in antiviral gene therapies, including those based on the disruption of entry receptors or that target viral genomes using targeted nucleases, such as the CRISPR/Cas9 system. In addition, new ways to express circulating antiviral factors, such as antibodies, and approaches to harness and engineer the immune system to provide an antiviral effect that is not naturally achieved are described.

Legal issues regarding gene editing at the beginning of life: an EU perspective

The development of clustered regularly interspaced short palindromic repeats (CRISPR)–Cas gene-modification technologies has opened impressive possibilities for the biomedical sciences. However, their application to human embryos and early fetuses has raised huge ethical and legal discussions because it affects the human germline. This paper provides a critical and in-depth analysis of the current legal framework on this topic in the EU context and at the national level in the member states. It also offers an alternative interpretation of the regulation, so as to help researchers, practitioners, policy makers and society as a whole to find efficient responses to challenges that cannot wait for a legally updated answer. As a final result, this paper will show that eugenic uses of CRISP–Cas and any kind of modification intended to alter the human germ line are generally banned in the EU context, while basic research on human embryos is mostly permitted. The legal status of therapeutic applications of CRISPR–Cas on early fetuses, however, has not been adequately addressed by the EU zone regulation.

Gene editing tools: state-of-the-art and the road ahead for the model and non-model fishes

Advancements in the DNA sequencing technologies and computational biology have revolutionized genome/transcriptome sequencing of non-model fishes at an affordable cost. This has led to a paradigm shift with regard to our heightened understandings of structure-functional relationships of genes at a global level, from model animals/fishes to non-model large animals/fishes. Whole genome/transcriptome sequencing technologies were supplemented with the series of discoveries in gene editing tools, which are being used to modify genes at pre-determined positions using programmable nucleases to explore their respective in vivo functions. For a long time, targeted gene disruption experiments were mostly restricted to embryonic stem cells, advances in gene editing technologies such as zinc finger nuclease, transcriptional activator-like effector nucleases and CRISPR (clustered regulatory interspaced short palindromic repeats)/CRISPR-associated nucleases have facilitated targeted genetic modifications beyond stem cells to a wide range of somatic cell lines across species from laboratory animals to farmed animals/fishes. In this review, we discuss use of different gene editing tools and the strategic implications in fish species for basic and applied biology research.

Therapeutic gene editing: delivery and regulatory perspectives

Gene-editing technology is an emerging therapeutic modality for manipulating the eukaryotic genome by using target-sequence-specific engineered nucleases. Because of the exceptional advantages that gene-editing technology offers in facilitating the accurate correction of sequences in a genome, gene editing-based therapy is being aggressively developed as a next-generation therapeutic approach to treat a wide range of diseases. However, strategies for precise engineering and delivery of gene-editing nucleases, including zinc finger nucleases, transcription activator-like effector nuclease, and CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats-associated nuclease Cas9), present major obstacles to the development of gene-editing therapies, as with other gene-targeting therapeutics. Currently, viral and non-viral vectors are being studied for the delivery of these nucleases into cells in the form of DNA, mRNA, or proteins. Clinical trials are already ongoing, and in vivo studies are actively investigating the applicability of CRISPR/Cas9 techniques. However, the concept of correcting the genome poses major concerns from a regulatory perspective, especially in terms of safety. This review addresses current research trends and delivery strategies for gene editing-based therapeutics in non-clinical and clinical settings and considers the associated regulatory issues.

Ethical issues of CRISPR technology and gene editing through the lens of solidarity

BACKGROUND

The avalanche of commentaries on CRISPR-Cas9 technology, a bacterial immune system modified to recognize any short DNA sequence, cut it out, and insert a new one, has rekindled hopes for gene therapy and other applications and raised criticisms of engineering genes in future generations.

SOURCES OF DATA

This discussion draws on articles that emphasize ethics, identified partly through PubMed and Google, 2014-2016.

AREAS OF AGREEMENT

CRISPR-Cas9 has taken the pace and prospects for genetic discovery and applications to a high level, stoking anticipation for somatic gene engineering to help patients. We support a moratorium on germ line manipulation.

AREAS OF CONTROVERSY

We place increased emphasis on the principle of solidarity and the public good. The genetic bases of some diseases are not thoroughly addressable with CRISPR-Cas9. We see no new ethical issues, compared with gene therapy and genetic engineering in general, apart from the explosive rate of findings. Other controversies include eugenics, patentability and unrealistic expectations of professionals and the public.

GROWING POINTS

Biggest issues are the void of research on human germ cell biology, the appropriate routes for oversight and transparency, and the scientific and ethical areas of reproductive medicine.

AREAS TIMELY FOR DEVELOPING RESEARCH

The principle of genomic solidarity and priority on public good should be a lens for bringing clarity to CRISPR debates. The valid claim of genetic exceptionalism supports restraint on experimentation in human germ cells, given the trans-generational dangers and the knowledge gap in germ cell biology.

Sickle cell disease: an international survey of results of HLA-identical sibling hematopoietic stem cell transplantation

Despite advances in supportive therapy to prevent complications of sickle cell disease (SCD), access to care is not universal. Hematopoietic cell transplantation is, to date, the only curative therapy for SCD, but its application is limited by availability of a suitable HLA-matched donor and lack of awareness of the benefits of transplant. Included in this study are 1000 recipients of HLA-identical sibling transplants performed between 1986 and 2013 and reported to the European Society for Blood and Marrow Transplantation, Eurocord, and the Center for International Blood and Marrow Transplant Research. The primary endpoint was event-free survival, defined as being alive without graft failure; risk factors were studied using a Cox regression models. The median age at transplantation was 9 years, and the median follow-up was longer than 5 years. Most patients received a myeloablative conditioning regimen (n = 873; 87%); the remainder received reduced-intensity conditioning regimens (n = 125; 13%). Bone marrow was the predominant stem cell source (n = 839; 84%); peripheral blood and cord blood progenitors were used in 73 (7%) and 88 (9%) patients, respectively. The 5-year event-free survival and overall survival were 91.4% (95% confidence interval, 89.6%-93.3%) and 92.9% (95% confidence interval, 91.1%-94.6%), respectively. Event-free survival was lower with increasing age at transplantation (hazard ratio [HR], 1.09; P < .001) and higher for transplantations performed after 2006 (HR, 0.95; P = .013). Twenty-three patients experienced graft failure, and 70 patients (7%) died, with the most common cause of death being infection. The excellent outcome of a cohort transplanted over the course of 3 decades confirms the role of HLA-identical sibling transplantation for children and adults with SCD.

Recent advances in T-cell immunotherapy for haematological malignancies

In vitro discoveries have paved the way for bench-to-bedside translation in adoptive T cell immunotherapy, resulting in remarkable clinical responses in a variety of haematological malignancies. Adoptively transferred T cells genetically modified to express CD19 CARs have shown great promise, although many unanswered questions regarding how to optimize T-cell therapies for both safety and efficacy remain. Similarly, T cells that recognize viral or tumour antigens though their native receptors have produced encouraging clinical responses. Honing manufacturing processes will increase the availability of T-cell products, while combining T-cell therapies has the ability to increase complete response rates. Lastly, innovative mechanisms to control these therapies may improve safety profiles while genome editing offers the prospect of modulating T-cell function. This review will focus on recent advances in T-cell immunotherapy, highlighting both clinical and pre-clinical advances, as well as exploring what the future holds.

Investigating Leber's hereditary optic neuropathy: Cell models and future perspectives

Leber's hereditary optic neuropathy (LHON) was the first human disease found to be associated with a mitochondrial DNA (mtDNA) point mutation. The most common LHON mutations are 11778G>A, 3460G>A or 14484T>C. The most common clinical features of LHON are optic nerve and retina atrophy. The affected tissue is not available for studies, therefore a variety of other cell types are used. However, all models face difficulties and limitations in mitochondrial disease research. The advantages and disadvantages of different cell models used to study LHON, recent advances in animal model generation and novel approaches in this field are discussed.

Antiviral therapy of persistent viral infection using genome editing

Chronic viral infections are often incurable because current antiviral strategies do not target chromosomally integrated or non-replicating episomal viral genomes. The rapid development of technologies for genome editing may possibly soon allow for therapeutic targeting of viral genomes and, hence, for development of curative strategies for persistent viral infection. However, detailed investigation of different antiviral genome editing approaches recently revealed various undesired effects. In particular, the problem of frequent and swift development of resistant viruses has to be thoroughly analysed before genome editing approaches become an established option for antiviral treatment.