Prevention of muscular dystrophy in mice by CRISPR/Cas9-mediated editing of germline DNA

Advances in human induced pluripotent stem cell (hiPSC)-based disease modelling in cardiogenetics

Human induced pluripotent stem cell (hiPSC)-based disease modelling has significantly advanced the field of cardiogenetics, providing a precise, patient-specific platform for studying genetic causes of heart diseases. Coupled with genome editing technologies such as CRISPR/Cas, hiPSC-based models not only allow the creation of isogenic lines to study mutation-specific cardiac phenotypes, but also enable the targeted modulation of gene expression to explore the effects of genetic and epigenetic deficits at the cellular and molecular level. hiPSC-based models of heart disease range from two-dimensional cultures of hiPSC-derived cardiovascular cell types, such as various cardiomyocyte subtypes, endothelial cells, pericytes, vascular smooth muscle cells, cardiac fibroblasts, immune cells, etc., to cardiac tissue cultures including organoids, microtissues, engineered heart tissues, and microphysiological systems. These models are further enhanced by multi-omics approaches, integrating genomic, transcriptomic, epigenomic, proteomic, and metabolomic data to provide a comprehensive view of disease mechanisms. In particular, advances in cardiovascular tissue engineering enable the development of more physiologically relevant systems that recapitulate native heart architecture and function, allowing for more accurate modelling of cardiac disease, drug screening, and toxicity testing, with the overall goal of personalised medical approaches, where therapies can be tailored to individual genetic profiles. Despite significant progress, challenges remain in the maturation of hiPSC-derived cardiomyocytes and the complexity of reproducing adult heart conditions. Here, we provide a concise update on the most advanced methods of hiPSC-based disease modelling in cardiogenetics, with a focus on genome editing and cardiac tissue engineering.

The road toward AAV-mediated gene therapy of Duchenne muscular dystrophy

Forty years after the dystrophin gene was cloned, significant progress has been made in developing gene therapy approaches for Duchenne muscular dystrophy (DMD). The disorder has presented numerous challenges, including the enormous size of the gene (2.2 MB), the need to target muscles body wide, and immunogenic issues against both vectors and dystrophin. Among human genetic disorders, DMD is relatively common, and the genetics are complicated since one-third of all cases arise from a spontaneous new mutation, resulting in thousands of independent lesions throughout the locus. Many approaches have been pursued in the goal of finding an effective therapy, including exon skipping, nonsense codon suppression, upregulation of surrogate genes, gene replacement, and gene editing. Here, we focus specifically on methods using AAV vectors, as these approaches have been tested in numerous clinical trials and are able to target muscles systemically. We discuss early advances to understand the structure of dystrophin, which are crucial for the design of effective DMD gene therapies. Included is a summary of efforts to deliver micro-, mini-, and full-length dystrophins to muscles. Finally, we review current approaches to adapt gene editing to the enormous DMD gene with prospects for improved therapies using all these methods.

Tissue Engineering and Regenerative Medicine: Perspectives and Challenges

From the pioneering days of cell therapy to the achievement of bioprinting organs, tissue engineering, and regenerative medicine have seen tremendous technological advancements, offering solutions for restoring damaged tissues and organs. However, only a few products and technologies have received United States Food and Drug Administration approval. This review highlights significant progress in cell therapy, extracellular vesicle-based therapy, and tissue engineering. Hematopoietic stem cell transplantation is a powerful tool for treating many diseases, especially hematological malignancies. Mesenchymal stem cells have been extensively studied. The discovery of induced pluripotent stem cells has revolutionized disease modeling and regenerative applications, paving the way for personalized medicine. Gene therapy represents an innovative approach to the treatment of genetic disorders. Additionally, extracellular vesicle-based therapies have emerged as rising stars, offering promising solutions in diagnostics, cell-free therapeutics, drug delivery, and targeted therapy. Advances in tissue engineering enable complex tissue constructs, further transforming the field. Despite these advancements, many technical, ethical, and regulatory challenges remain. This review addresses the current bottlenecks, emphasizing novel technologies and interdisciplinary research to overcome these hurdles. Standardizing practices and conducting clinical trials will balance innovation and regulation, improving patient outcomes and quality of life.

The Potential of RNA Therapeutics in Treating Cardiovascular Disease

Despite significant advances in cardiology over the past few decades, cardiovascular diseases (CVDs) remain the leading cause of global mortality and morbidity. This underscores the need for novel therapeutic interventions that go beyond symptom management to address the underlying causal mechanisms of CVDs. RNA-based therapeutics represent a new class of drugs capable of regulating specific genetic and molecular pathways, positioning them as strong candidates for targeting the root causes of a wide range of diseases. Moreover, owing to the vast diversity in RNA form and function, these molecules can be utilized to induce changes at different levels of gene expression regulation, making them suitable for a broad array of medical applications, even within a single disease context. Several RNA-based therapies are currently being investigated for their potential to address various CVD pathologies. These include treatments aimed at promoting cardiac revascularization and regeneration, preventing cardiomyocyte apoptosis, reducing harmful circulating cholesterols and fats, lowering blood pressure, reversing cardiac fibrosis and remodeling, and correcting the genetic basis of inherited CVDs. In this review, we discuss the current landscape of RNA therapeutics for CVDs, with an emphasis on their classifications, modes of action, advancements in delivery strategies and considerations for their implementation, as well as CVD targets with proven therapeutic potential.

Gene Editing for Duchenne Muscular Dystrophy: From Experimental Models to Emerging Therapies

The CRISPR system has emerged as a ground-breaking gene-editing tool, offering promising therapeutic potential for Duchenne muscular dystrophy (DMD), a severe genetic disorder affecting approximately 1 in 5000 male births globally. DMD is caused by mutations in the dystrophin gene, which encodes a critical membrane-associated protein essential for maintaining muscle structure, function and repair. Patients with DMD experience progressive muscle degeneration, loss of ambulation, respiratory insufficiency, and cardiac failure, with most succumbing to the disease by their third decade of life. Despite the well-characterized genetic basis of DMD, curative treatments- such as exon skipping therapies, micro-dystrophin, and steroids- remain elusive. Recent preclinical studies have demonstrated the promise of CRISPR-based approaches in restoring dystrophin expression across various models, including human cells, murine systems, and large animal models. These advancements highlight the potential of gene editing to fundamentally alter the trajectory of the disease. However, significant challenges persist, including immunogenicity, off-target effects, and limited editing efficiency, which hinder clinical translation. This review provides a comprehensive analysis of the latest developments in CRISPR-based therapeutic strategies for DMD. It emphasizes the need for further innovation in gene-editing technologies, delivery systems, and rigorous safety evaluations to overcome current barriers and harness the full potential of CRISPR/Cas as a durable and effective treatment for DMD.

Advances in Duchenne Muscular Dystrophy: Diagnostic Techniques and Dystrophin Domain Insights

Abnormalities in X chromosomes, either numerical or structural, cause X-linked disorders, such as Duchenne muscular dystrophy (DMD). Recent molecular and cytogenetic techniques can help identify DMD gene mutations. The accurate diagnosis of Duchenne is crucial, directly impacting patient treatment management, genetics, and the establishment of effective prevention strategies. This review provides an overview of X chromosomal disorders affecting Duchenne and discusses how mutations in Dystrophin domains can impact detection accuracy. Firstly, the efficiency and use of cytogenetic and molecular techniques for the genetic diagnosis of Duchenne disease have, thus, become increasingly important. Secondly, artificial intelligence (AI) will be instrumental in developing future therapies by enabling the aggregation and synthesis of extensive and heterogeneous datasets, thereby elucidating underlying molecular mechanisms. However, despite advances in diagnostic technology, understanding the role of Dystrophin in Duchenne disease remains a challenge. Therefore, this review aims to synthesize this complex information to significantly advance the understanding of DMD and how it could affect patient care.

Precisely Targeted Nanoparticles for CRISPR-Cas9 Delivery in Clinical Applications

Clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR-Cas9), an emerging gene-editing technology, has recently gained rapidly increasing attention. However, the lack of efficient delivery vectors to deliver CRISPR-Cas9 to specific cells or tissues has hindered the translation of this biotechnology into clinical applications. Chemically synthesized nanoparticles (NPs), as attractive non-viral delivery platforms for CRISPR-Cas9, have been extensively investigated because of their unique characteristics, such as controllable size, high stability, multi-functionality, bio-responsive behavior, biocompatibility, and versatility in chemistry. In this review, the key considerations for the precise design of chemically synthesized-based nanoparticles include efficient encapsulation, cellular uptake, the targeting of specific tissues and cells, endosomal escape, and controlled release. We discuss cutting-edge strategies to integrate chemical modifications into non-viral nanoparticles that guide the CRISPR-Cas9 genome-editing machinery to specific edits. We also highlighted the rationale of intelligent nanoparticle design. In particular, we have summarized promising functional groups and molecules that can effectively optimize carrier function. In addition, this review focuses on advances in the widespread application of NPs delivery in the biomedical fields to promote the development of safe, specific, and efficient NPs for delivering CRISPR-Cas9 systems, providing references for accelerating their clinical translational applications.

Is Duchenne gene therapy a suitable treatment despite its immunogenic class effect?

INTRODUCTION

Duchenne muscular dystrophy (DMD) is a severe X-linked disorder characterized by progressive muscle weakness and eventual death due to cardiomyopathy or respiratory complications. Currently, there is no cure for DMD, with standard treatments primarily focusing on symptom management. Using immunosuppressive measures and optimized vector designs allows for gene therapies to better address the genetic cause of the disease.

AREAS COVERED

This review evaluates the efficacy and safety of emerging DMD gene therapies as of 2024. It also discusses the potential of utrophin upregulation, gene editing, and truncated dystrophin as therapeutic strategies. It highlights safety concerns associated with these therapies, including adverse events and patient deaths. A comprehensive overview of developments covers topics such as CRISPR-Cas9 therapies, micro-dystrophin, and the potential delivery of full-length dystrophin.

EXPERT OPINION

The FDA's recent approval of delandistrogene moxeparvovec (Elevidys) underscores the promise of gene replacement therapies for DMD patients. Understanding the mechanisms behind the adverse effects and excluding patients with specific pathogenic variants may enhance the safety profiles of these therapies. CRISPR/Cas9 therapies, while promising, face significant regulatory and safety challenges that hinder their clinical application. Optimal DMD therapies should target both skeletal and cardiac muscles to be effective.

Recent advances in therapeutic gene-editing technologies

The advent of gene-editing technologies, particularly CRISPR-based systems, has revolutionized the landscape of biomedical research and gene therapy. Ongoing research in gene editing has led to the rapid iteration of CRISPR technologies, such as base and prime editors, enabling precise nucleotide changes without the need for generating harmful double-strand breaks (DSBs). Furthermore, innovations such as CRISPR fusion systems with DNA recombinases, DNA polymerases, and DNA ligases have expanded the size limitations for edited sequences, opening new avenues for therapeutic development. Beyond the CRISPR system, mobile genetic elements (MGEs) and epigenetic editors are emerging as efficient alternatives for precise large insertions or stable gene manipulation in mammalian cells. These advances collectively set the stage for next-generation gene therapy development. This review highlights recent developments of genetic and epigenetic editing tools and explores preclinical innovations poised to advance the field.

Characterization of diverse Cas9 orthologs for genome and epigenome editing

CRISPR-Cas9 systems have revolutionized biotechnology, creating diverse new opportunities for biomedical research and therapeutic genome and epigenome editing. Despite the abundance of bacterial CRISPR-Cas9 systems, relatively few are effective in human cells, limiting the overall potential of CRISPR technology. To expand the CRISPR-Cas toolbox, we characterized a set of type II CRISPR-Cas9 systems from select bacterial genera and species encoding diverse Cas9s. Four systems demonstrated robust and specific gene repression in human cells when used as nuclease-null dCas9s fused with a KRAB domain and were also highly active nucleases in human cells. These systems have distinct protospacer adjacent motifs (PAMs), including AT-rich motifs and sgRNA features orthogonal to the commonly used Staphylococcus aureus and Streptococcus pyogenes Cas9s. Additionally, we assessed gene activation when fused with the p300 catalytic domain. Notably, S. uberis Cas9 performed competitively against benchmarks with promising repression, activation, nuclease, and base editing activity. This study expands the CRISPR-Cas9 repertoire, enabling effective genome and epigenome editing for diverse applications.

Rescue of the disease-associated phenotype in CRISPR-corrected hiPSCs as a therapeutic approach for inherited retinal dystrophies

Inherited retinal dystrophies (IRDs), such as retinitis pigmentosa and Stargardt disease, are a group of rare diseases caused by mutations in more than 300 genes that currently have no treatment in most cases. They commonly trigger blindness and other ocular affectations due to retinal cell degeneration. Gene editing has emerged as a promising and powerful strategy for the development of IRD therapies, allowing the permanent correction of pathogenic variants. Using clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 and transcription activator-like effector nucleases (TALEN) gene-editing tools, we precisely corrected seven hiPS cell lines derived from IRD patients carrying mutations in ABCA4, BEST1, PDE6A, PDE6C, RHO, or USH2A. Homozygous mutations and point insertions/deletions resulted in the highest homology-directed repair efficiencies, with at least half of the clones repaired properly without off-target effects. Strikingly, correction of a heterozygous pathogenic variant was achieved using the wild-type allele of the patient as the template for DNA repair. These results suggest the unexpected potential application of CRISPR as a donor template-free strategy for single-nucleotide modifications. Additionally, the corrected clones exhibited a reversion of the disease-associated phenotype in retinal cellular models. These data strengthen the study and application of gene editing-based approaches for IRD treatment.

Nature Inspired Delivery Vehicles for CRISPR-Based Genome Editing

The advent of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-based genome editing technologies has opened up groundbreaking possibilities for treating a wide spectrum of genetic disorders and diseases. However, the success of these technologies relies heavily on the development of efficient and safe delivery systems. Among the most promising approaches are natural and synthetic nanocarrier-mediated delivery systems, including viral vectors, extracellular vesicles (EVs), engineered cellular membrane particles, liposomes, and various nanoparticles. These carriers enhance the efficacy of the CRISPR system by providing a unique combination of efficiency, specificity, and reduced immunogenicity. Synthetic carriers such as liposomes and nanoparticles facilitate CRISPR delivery with high reproducibility and customizable functions. Viral vectors, renowned for their high transduction efficiency and broad tropism, serve as powerful vehicles for delivering CRISPR components to various cell types. EVs, as natural carriers of RNA and proteins, offer a stealth mechanism to evade immune detection, allowing for the targeted delivery of genome editors with minimal off-target effects. Engineered cellular membrane particles further improve delivery by simulating the cellular environment, enhancing uptake, and minimizing immune response. This review explores the innovative integration of CRISPR genome editors with various nanocarrier systems, focusing on recent advancements, applications, and future directions in therapeutic genome editing.

Phospholipase C epsilon 1 as a therapeutic target in cardiovascular diseases

BACKGROUND

Phospholipase C epsilon 1 (PLCε1) can hydrolyze phosphatidylinositol-4,5-bisphosphate and phosphatidylinositol-4-phosphate at the plasma membrane and perinuclear membrane in the cardiovascular system, producing lipid-derived second messengers. These messengers are considered prominent triggers for various signal transduction processes. Notably, diverse cardiac phenotypes have been observed in cardiac-specific and global Plce1 knockout mice under conditions of pathological stress. It is well established that the cardiac-specific Plce1 knockout confers cardioprotective benefits. Therefore, the development of tissue/cell-specific targeting approaches is critical for advancing therapeutic interventions.

AIM OF REVIEW

This review aims to distill the foundational biology and functional significance of PLCε1 in cardiovascular diseases, as well as to explore potential avenues for research and the development of novel therapeutic strategies targeting PLCε1.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Cardiovascular diseases remain the leading cause of morbidity and mortality worldwide, with incidence rates escalating annually. A comprehensive understanding of the multifaceted role of PLCε1 is essential for enhancing the diagnosis, management, and prognostic assessment of patients suffering from cardiovascular diseases.

Rational engineering of minimally immunogenic nucleases for gene therapy

Genome editing using CRISPR-Cas systems is a promising avenue for the treatment of genetic diseases. However, cellular and humoral immunogenicity of genome editing tools, which originate from bacteria, complicates their clinical use. Here we report reduced immunogenicity (Red)(i)-variants of two clinically relevant nucleases, SaCas9 and AsCas12a. Through MHC-associated peptide proteomics (MAPPs) analysis, we identify putative immunogenic epitopes on each nuclease. Using computational modeling, we rationally design these proteins to evade the immune response. SaCas9 and AsCas12a Redi variants are substantially less recognized by adaptive immune components, including reduced binding affinity to MHC molecules and attenuated generation of cytotoxic T cell responses, yet maintain wild-type levels of activity and specificity. In vivo editing of PCSK9 with SaCas9.Redi.1 is comparable in efficiency to wild-type SaCas9, but significantly reduces undesired immune responses. This demonstrates the utility of this approach in engineering proteins to evade immune detection.

Gene editing tool-loaded biomimetic cationic vesicles with highly efficient bacterial internalization for in vivo eradication of pathogens

In the post-COVID-19 era, drug-resistant bacterial infections emerge as one of major death causes, where multidrug-resistant Acinetobacter baumannii (MRAB) and drug-resistant Pseudomonas aeruginosa (DRPA) represent primary pathogens. However, the classical antibiotic strategy currently faces the bottleneck of drug resistance. We develop an antimicrobial strategy that applies the selective delivery of CRISPR/Cas9 plasmids to pathogens with biomimetic cationic hybrid vesicles (BCVs), irrelevant to bacterial drug resistance. CRISPR/Cas9 plasmids were constructed, replicating in MRAB or DRPA and expressing ribonucleic proteins, leading to irreparable chromosomal lesions; however, delivering the negatively charged plasmids with extremely large molecular weight to the pathogens at the infection site became a huge challenge. We found that the BCVs integrating the bacterial out membrane vesicles and cationic lipids efficiently delivered the plasmids in vitro/in vivo to the pathogens followed by effective internalization. The BCVs were used by intratracheal or topical hydrogel application against MRAB pulmonary infection or DRPA wound infection, and both of the two pathogens were eradicated from the lung or the wound. CRISPR/Cas9 plasmid-loaded BCVs become a promising medication for drug-resistant bacteria infections.

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.

The Role of CRISPR/Cas9 in Revolutionizing Duchenne's Muscular Dystrophy Treatment: Opportunities and Obstacles

Duchenne's muscular dystrophy (DMD) is a severe X-linked disorder characterized by progressive muscle degeneration, leading to loss of ambulation, respiratory failure, and premature death. It affects approximately 1 in 3,500 live male births and is caused by mutations in the dystrophin gene, which impairs muscle fiber stability. Current treatments are limited to managing symptoms and slowing disease progression, with no curative therapies available. The advent of CRISPR/Cas9 gene-editing technology has introduced a promising approach for directly correcting the genetic mutations responsible for DMD. This review explores the potential of CRISPR/Cas9 as a transformative therapy for DMD, highlighting its successes in preclinical models, the challenges associated with its delivery, and the obstacles to its clinical application. While preclinical studies demonstrate the efficacy of CRISPR/Cas9 in restoring dystrophin expression and improving muscle function, significant hurdles remain, including optimizing delivery methods and ensuring long-term safety.

Application of CRISPR/Cas9 System in the Treatment of Alzheimer's Disease and Neurodegenerative Diseases

Alzheimer's, Parkinson's, and Huntington's are some of the most common neurological disorders, which affect millions of people worldwide. Although there have been many treatments for these diseases, there are still no effective treatments to treat or completely stop these disorders. Perhaps the lack of proper treatment for these diseases can be related to various reasons, but the poor results related to recent clinical research also prompted doctors to look for new treatment approaches. In this regard, various researchers from all over the world have provided many new treatments, one of which is CRISPR/Cas9. Today, the CRISPR/Cas9 system is mostly used for genetic modifications in various species. In addition, by using the abilities available in the CRISPR/Cas9 system, researchers can either remove or modify DNA sequences, which in this way can establish a suitable and useful treatment method for the treatment of genetic diseases that have undergone mutations. We conducted a non-systematic review of articles and study results from various databases, including PubMed, Medline, Web of Science, and Scopus, in recent years. and have investigated new treatment methods in neurodegenerative diseases with a focus on Alzheimer's disease. Then, in the following sections, the treatment methods were classified into three groups: anti-tau, anti-amyloid, and anti-APOE regimens. Finally, we discussed various applications of the CRISPR/Cas-9 system in Alzheimer's disease. Today, using CRISPR/Cas-9 technology, scientists create Alzheimer's disease models that have a more realistic phenotype and reveal the processes of pathogenesis; following the screening of defective genes, they establish treatments for this disease.

Gene editing in common cardiovascular diseases

Cardiovascular diseases are the leading cause of morbidity and mortality worldwide, highlighting the high socioeconomic impact. Current treatment strategies like compound-based drugs or surgeries are often limited. On the one hand, systemic administration of substances is frequently associated with adverse side effects; on the other hand, they typically provide only short-time effects requiring daily intake. Thus, new therapeutic approaches and concepts are urgently needed. The advent of CRISPR-Cas9 genome editing offers great promise for the correction of disease-causing hereditary mutations. As such mutations are often very rare, gene editing strategies to correct them are not broadly applicable to many patients. Notably, there is recent evidence that gene editing technology can also be deployed to disrupt common pathogenic signaling cascades in a targeted, specific, and efficient manner, which offers a more generalizable approach. However, several challenges remain to be addressed ranging from the optimization of the editing strategy itself to a suitable delivery strategy up to potential immune responses to the editing components. This review article discusses important CRISPR-Cas9-based gene editing approaches with their advantages and drawbacks and outlines opportunities in their application for treatment of cardiovascular diseases.

Targeting DLBCL by mutation-specific disruption of cancer-driving oncogenes

Diffuse large B cell lymphomas (DLBCL) are highly aggressive tumors. Their genetic complexity and heterogeneity have hampered the development of novel approaches for precision medicine. Our study aimed to develop a personalized therapy for DLBCL by utilizing the CRISPR/Cas system to induce knockouts (KO) of driver genes, thereby causing cancer cell death while minimizing side effects. We focused on OCI-LY3 cells, modeling DLBCL, and compared them with BJAB cells as controls. Analysis of whole exome sequencing revealed significant mutations in genes like PAX5, CD79B, and MYC in OCI-LY3 cells. CRISPR/Cas9-mediated KO of these genes resulted in reduced cancer cell viability. Subsequent single and dual gRNA targeting of PAX5 mutations inhibited proliferation specifically in OCI-LY3 cells. Moreover, dual gRNA targeting of PAX5 and MYC induced chromosomal rearrangements, reducing cell proliferation substantially. However, targeting single intronic mutations did not affect cell viability, highlighting the importance of disrupting protein function. Targeting multiple mutations simultaneously addresses intra-tumoral heterogeneity, and the transient delivery of CRISPR/Cas9 allows for permanent gene disruption. While challenges such as incomplete editing efficiency and delivery limitations exist, further optimization may enhance therapeutic efficacy. Overall, our findings demonstrate the efficacy of CRISPR/Cas9 in targeting oncogenic mutations, opening avenues for precision medicine in DLBCL treatment.

Human embryonic genetic mosaicism and its effects on development and disease

Nearly every mammalian cell division is accompanied by a mutational event that becomes fixed in a daughter cell. When carried forward to additional cell progeny, a clone of variant cells can emerge. As a result, mammals are complex mosaics of clones that are genetically distinct from one another. Recent high-throughput sequencing studies have revealed that mosaicism is common, clone sizes often increase with age and specific variants can affect tissue function and disease development. Variants that are acquired during early embryogenesis are shared by multiple cell types and can affect numerous tissues. Within tissues, variant clones compete, which can result in their expansion or elimination. Embryonic mosaicism has clinical implications for genetic disease severity and transmission but is likely an under-recognized phenomenon. To better understand its implications for mosaic individuals, it is essential to leverage research tools that can elucidate the mechanisms by which expanded embryonic variants influence development and disease.

Pig models for translational Duchenne muscular dystrophy research

Duchenne muscular dystrophy (DMD) is caused by mutations in the X-linked DMD gene, resulting in the absence of dystrophin, progressive muscle degeneration, and heart failure. Genetically tailored pig models resembling human DMD mutations recapitulate the biochemical, clinical, and pathological hallmarks of DMD with an accelerated disease progression compared to human patients. DMD pigs have been used to evaluate therapeutic concepts such as gene editing to reframe a disrupted DMD reading frame or the delivery of artificial chromosome vectors carrying the complete DMD gene. Moreover, DMD pigs have been instrumental in validating new diagnostic modalities such as multispectral optoacoustic tomography (MSOT) for non-invasive monitoring of disease progression. DMD pigs may thus help to bridge the gap between proof-of-concept studies in cellular or rodent models and clinical studies in patients.

T4 DNA polymerase prevents deleterious on-target DNA damage and enhances precise CRISPR editing

Unintended on-target chromosomal alterations induced by CRISPR/Cas9 in mammalian cells are common, particularly large deletions and chromosomal translocations, and present a safety challenge for genome editing. Thus, there is still an unmet need to develop safer and more efficient editing tools. We screened diverse DNA polymerases of distinct origins and identified a T4 DNA polymerase derived from phage T4 that strongly prevents undesired on-target damage while increasing the proportion of precise 1- to 2-base-pair insertions generated during CRISPR/Cas9 editing (termed CasPlus). CasPlus induced substantially fewer on-target large deletions while increasing the efficiency of correcting common frameshift mutations in DMD and restored higher level of dystrophin expression than Cas9-alone in human cardiomyocytes. Moreover, CasPlus greatly reduced the frequency of on-target large deletions during mouse germline editing. In multiplexed guide RNAs mediating gene editing, CasPlus repressed chromosomal translocations while maintaining gene disruption efficiency that was higher or comparable to Cas9 in primary human T cells. Therefore, CasPlus offers a safer and more efficient gene editing strategy to treat pathogenic variants or to introduce genetic modifications in human applications.

Neuromuscular Disorders in Pediatric Respiratory Disease

Respiratory sequelae are a frequent cause of morbidity and mortality in children with NMD. Impaired cough strength and resulting airway clearance as well as sleep disordered breathing are the two main categories of respiratory sequelae. Routine clinical evaluation and diagnostic testing by pulmonologists is an important pillar of the multidisciplinary care required for children with NMD. Regular surveillance for respiratory disease and timely implementation of treatment including pulmonary clearance techniques as well as ventilation can prevent respiratory related morbidity including hospital admissions and improve survival. Additionally, novel disease modifying therapies for some NMDs are now available which has significantly improved the clinical trajectories of patients resulting in a paradigm shift in clinical care. Pulmonologists are 'learning' the new natural history for these diseases and adjusting clinical management accordingly.

Correction of human nonsense mutation via adenine base editing for Duchenne muscular dystrophy treatment in mouse

Duchenne muscular dystrophy (DMD) is the most prevalent herediatry disease in men, characterized by dystrophin deficiency, progressive muscle wasting, cardiac insufficiency, and premature mortality, with no effective therapeutic options. Here, we investigated whether adenine base editing can correct pathological nonsense point mutations leading to premature stop codons in the dystrophin gene. We identified 27 causative nonsense mutations in our DMD patient cohort. Treatment with adenine base editor (ABE) could restore dystrophin expression by direct A-to-G editing of pathological nonsense mutations in cardiomyocytes generated from DMD patient-derived induced pluripotent stem cells. We also generated two humanized mouse models of DMD expressing mutation-bearing exons 23 or 30 of human dystrophin gene. Intramuscular administration of ABE, driven by ubiquitous or muscle-specific promoters could correct these nonsense mutations in vivo, albeit with higher efficiency in exon 30, restoring dystrophin expression in skeletal fibers of humanized DMD mice. Moreover, a single systemic delivery of ABE with human single guide RNA (sgRNA) could induce body-wide dystrophin expression and improve muscle function in rotarod tests of humanized DMD mice. These findings demonstrate that ABE with human sgRNAs can confer therapeutic alleviation of DMD in mice, providing a basis for development of adenine base editing therapies in monogenic diseases.

Various repair events following CRISPR/Cas9-based mutational correction of an infertility-related mutation in mouse embryos

PURPOSE

Unpredictable genetic modifications and chromosomal aberrations following CRISPR/Cas9 administration hamper the efficacy of germline editing. Repair events triggered by double-strand DNA breaks (DSBs) besides non-homologous end joining and repair template-driven homology-directed repair have been insufficiently investigated in mouse. In this work, we are the first to investigate the precise repair mechanisms triggered by parental-specific DSB induction in mouse for paternal mutational correction in the context of an infertility-related mutation.

METHODS

We aimed to correct a paternal 22-nucleotide deletion in Plcz1, associated with lack of fertilisation in vitro, by administrating CRISPR/Cas9 components during intracytoplasmic injection of Plcz1-null sperm in wild-type oocytes combined with assisted oocyte activation. Through targeted next-generation sequencing, 77 injected embryos and 26 blastomeres from seven injected embryos were investigated. In addition, low-pass whole genome sequencing was successfully performed on 17 injected embryo samples.

RESULTS

Repair mechanisms induced by two different CRISPR/Cas9 guide RNA (gRNA) designs were investigated. In 13.73% (7/51; gRNA 1) and 19.05% (4/21; gRNA 2) of the targeted embryos, only the wild-type allele was observed, of which the majority (85.71%; 6/7) showed integrity of the targeted chromosome. Remarkably, for both designs, only in one of these embryos (1/7; gRNA 1 and 1/4; gRNA2) could repair template use be detected. This suggests that alternative repair events have occurred. Next, various genetic events within the same embryo were detected after single-cell analysis of four embryos.

CONCLUSION

Our results suggest the occurrence of mosaicism and complex repair events after CRISPR/Cas9 DSB induction where chromosomal integrity is predominantly contained.

CRISPR-Cas9 delivery strategies and applications: Review and update

Nowadays, a significant part of the investigations carried out in the medical field belong to cancer treatment. Generally, conventional cancer treatments, including chemotherapy, radiotherapy, and surgery, which have been used for a long time, are not sufficient, especially in malignant cancers. Because genetic mutations cause cancers, researchers are trying to treat these diseases using genetic engineering tools. One of them is clustered regularly interspaced short palindromic repeats (CRISPR), a powerful tool in genetic engineering in the last decade. CRISPR, which forms the CRISPR-Cas structure with its endonuclease protein, Cas, is known as a part of the immune system (adaptive immunity) in bacteria and archaea. Among the types of Cas proteins, Cas9 endonuclease has been used in many scientific studies due to its high accuracy and efficiency. This review reviews the CRISPR system, focusing on the history, classification, delivery methods, applications, new generations, and challenges of CRISPR-Cas9 technology.

Exonuclease editor promotes precision of gene editing in mammalian cells

BACKGROUND

Many efforts have been made to improve the precision of Cas9-mediated gene editing through increasing knock-in efficiency and decreasing byproducts, which proved to be challenging.

RESULTS

Here, we have developed a human exonuclease 1-based genome-editing tool, referred to as exonuclease editor. When compared to Cas9, the exonuclease editor gave rise to increased HDR efficiency, reduced NHEJ repair frequency, and significantly elevated HDR/indel ratio. Robust gene editing precision of exonuclease editor was even superior to the fusion of Cas9 with E1B or DN1S, two previously reported precision-enhancing domains. Notably, exonuclease editor inhibited NHEJ at double strand breaks locally rather than globally, reducing indel frequency without compromising genome integrity. The replacement of Cas9 with single-strand DNA break-creating Cas9 nickase further increased the HDR/indel ratio by 453-fold than the original Cas9. In addition, exonuclease editor resulted in high microhomology-mediated end joining efficiency, allowing accurate and flexible deletion of targeted sequences with extended lengths with the aid of paired sgRNAs. Exonuclease editor was further used for correction of DMD patient-derived induced pluripotent stem cells, where 30.0% of colonies were repaired by HDR versus 11.1% in the control.

CONCLUSIONS

Therefore, the exonuclease editor system provides a versatile and safe genome editing tool with high precision and holds promise for therapeutic gene correction.

Chimeric Cell Therapies as a Novel Approach for Duchenne Muscular Dystrophy (DMD) and Muscle Regeneration

Chimerism-based strategies represent a pioneering concept which has led to groundbreaking advancements in regenerative medicine and transplantation. This new approach offers therapeutic potential for the treatment of various diseases, including inherited disorders. The ongoing studies on chimeric cells prompted the development of Dystrophin-Expressing Chimeric (DEC) cells which were introduced as a potential therapy for Duchenne Muscular Dystrophy (DMD). DMD is a genetic condition that leads to premature death in adolescent boys and remains incurable with current methods. DEC therapy, created via the fusion of human myoblasts derived from normal and DMD-affected donors, has proven to be safe and efficacious when tested in experimental models of DMD after systemic-intraosseous administration. These studies confirmed increased dystrophin expression, which correlated with functional and morphological improvements in DMD-affected muscles, including cardiac, respiratory, and skeletal muscles. Furthermore, the application of DEC therapy in a clinical study confirmed its long-term safety and efficacy in DMD patients. This review summarizes the development of chimeric cell technology tested in preclinical models and clinical studies, highlighting the potential of DEC therapy in muscle regeneration and repair, and introduces chimeric cell-based therapies as a promising, novel approach for muscle regeneration and the treatment of DMD and other neuromuscular disorders.

CRISPR-Based Gene Therapies: From Preclinical to Clinical Treatments

In recent years, clustered regularly interspaced short palindromic repeats (CRISPRs) and CRISPR-associated (Cas) protein have emerged as a revolutionary gene editing tool to treat inherited disorders affecting different organ systems, such as blood and muscles. Both hematological and neuromuscular genetic disorders benefit from genome editing approaches but face different challenges in their clinical translation. The ability of CRISPR/Cas9 technologies to modify hematopoietic stem cells ex vivo has greatly accelerated the development of genetic therapies for blood disorders. In the last decade, many clinical trials were initiated and are now delivering encouraging results. The recent FDA approval of Casgevy, the first CRISPR/Cas9-based drug for severe sickle cell disease and transfusion-dependent β-thalassemia, represents a significant milestone in the field and highlights the great potential of this technology. Similar preclinical efforts are currently expanding CRISPR therapies to other hematologic disorders such as primary immunodeficiencies. In the neuromuscular field, the versatility of CRISPR/Cas9 has been instrumental for the generation of new cellular and animal models of Duchenne muscular dystrophy (DMD), offering innovative platforms to speed up preclinical development of therapeutic solutions. Several corrective interventions have been proposed to genetically restore dystrophin production using the CRISPR toolbox and have demonstrated promising results in different DMD animal models. Although these advances represent a significant step forward to the clinical translation of CRISPR/Cas9 therapies to DMD, there are still many hurdles to overcome, such as in vivo delivery methods associated with high viral vector doses, together with safety and immunological concerns. Collectively, the results obtained in the hematological and neuromuscular fields emphasize the transformative impact of CRISPR/Cas9 for patients affected by these debilitating conditions. As each field suffers from different and specific challenges, the clinical translation of CRISPR therapies may progress differentially depending on the genetic disorder. Ongoing investigations and clinical trials will address risks and limitations of these therapies, including long-term efficacy, potential genotoxicity, and adverse immune reactions. This review provides insights into the diverse applications of CRISPR-based technologies in both preclinical and clinical settings for monogenic blood disorders and muscular dystrophy and compare advances in both fields while highlighting current trends, difficulties, and challenges to overcome.

Applications of genetic code expansion technology in eukaryotes

Unnatural amino acids (UAAs) have gained significant attention in protein engineering and drug development owing to their ability to introduce new chemical functionalities to proteins. In eukaryotes, genetic code expansion (GCE) enables the incorporation of UAAs and facilitates posttranscriptional modification (PTM), which is not feasible in prokaryotic systems. GCE is also a powerful tool for cell or animal imaging, the monitoring of protein interactions in target cells, drug development, and switch regulation. Therefore, there is keen interest in utilizing GCE in eukaryotic systems. This review provides an overview of the application of GCE in eukaryotic systems and discusses current challenges that need to be addressed.

Production of Duchenne muscular dystrophy cellular model using CRISPR-Cas9 exon deletion strategy

Duchenne Muscular Dystrophy (DMD) is a progressive muscle wasting disorder caused by loss-of-function mutations in the dystrophin gene. Although the search for a definitive cure has failed to date, extensive efforts have been made to introduce effective therapeutic strategies. Gene editing technology is a great revolution in biology, having an immediate application in the generation of research models. DMD muscle cell lines are reliable sources to evaluate and optimize therapeutic strategies, in-depth study of DMD pathology, and screening the effective drugs. However, only a few immortalized muscle cell lines with DMD mutations are available. In addition, obtaining muscle cells from patients also requires an invasive muscle biopsy. Mostly DMD variants are rare, making it challenging to identify a patient with a particular mutation for a muscle biopsy. To overcome these challenges and generate myoblast cultures, we optimized a CRISPR/Cas9 gene editing approach to model the most common DMD mutations that include approximately 28.2% of patients. GAP-PCR and sequencing results show the ability of the CRISPR-Cas9 system to efficient deletion of mentioned exons. We showed producing truncated transcript due to the targeted deletion by RT-PCR and sequencing. Finally, mutation-induced disruption of dystrophin protein expression was confirmed by western blotting. All together, we successfully created four immortalized DMD muscle cell lines and showed the efficacy of the CRISPR-Cas9 system for the generation of immortalized DMD cell models with the targeted deletions.

Recent Therapeutic Gene Editing Applications to Genetic Disorders

Recent years have witnessed unprecedented progress in therapeutic gene editing, revolutionizing the approach to treating genetic disorders. In this comprehensive review, we discuss the progression of milestones leading to the emergence of the clustered regularly interspaced short palindromic repeats (CRISPR)-based technology as a powerful tool for precise and targeted modifications of the human genome. CRISPR-Cas9 nuclease, base editing, and prime editing have taken center stage, demonstrating remarkable precision and efficacy in targeted ex vivo and in vivo genomic modifications. Enhanced delivery systems, including viral vectors and nanoparticles, have further improved the efficiency and safety of therapeutic gene editing, advancing their clinical translatability. The exploration of CRISPR-Cas systems beyond the commonly used Cas9, such as the development of Cas12 and Cas13 variants, has expanded the repertoire of gene editing tools, enabling more intricate modifications and therapeutic interventions. Outstandingly, prime editing represents a significant leap forward, given its unparalleled versatility and minimization of off-target effects. These innovations have paved the way for therapeutic gene editing in a multitude of previously incurable genetic disorders, ranging from monogenic diseases to complex polygenic conditions. This review highlights the latest innovative studies in the field, emphasizing breakthrough technologies in preclinical and clinical trials, and their applications in the realm of precision medicine. However, challenges such as off-target effects and ethical considerations remain, necessitating continued research to refine safety profiles and ethical frameworks.

CRISPR-Based Gene Editing Techniques in Pediatric Neurological Disorders

The emergence of gene editing technologies offers a unique opportunity to develop mutation-specific treatments for pediatric neurological disorders. Gene editing systems can potentially alter disease trajectory by correcting dysfunctional mutations or therapeutically altering gene expression. Clustered regularly interspaced short palindromic repeats (CRISPR)-based approaches are attractive gene therapy platforms to personalize treatments because of their specificity, ease of design, versatility, and cost. However, many such approaches remain in the early stages of development, with ongoing efforts to optimize editing efficiency, minimize unintended off-target effects, and mitigate pathologic immune responses. Given the rapid evolution of CRISPR-based therapies, it is prudent for the clinically based child neurologist to have a conceptual understanding of what such therapies may entail, including both benefits and risks and how such therapies may be clinically applied. In this review, we describe the fundamentals of CRISPR-based therapies, discuss the opportunities and challenges that have arisen, and highlight preclinical work in several pediatric neurological diseases.

The Use of CRISPR-Cas9 Genetic Technology in Cardiovascular Disease: A Comprehensive Review of Current Progress and Future Prospective

Over the last century, there have been major landmark developments in the field of medicine, enabling us to control and cure various diseases on a larger scale. A few of these include the discovery of antibiotics, the development of vaccines, and the origin of organ and tissue transplants. The continued quest for innovation in microbiology and medicine has helped humankind save millions of lives and decrease morbidity at the global level. Genetic medicine has grown significantly in the last two decades and appears to be the next frontier of curative therapies for chronic diseases. One important landmark in genetic medicine is the development of CRISPR (clustered, regularly interspaced short palindromic repeats) technology. In this article, we describe the basic structure and function of the CRISPR-Cas9 system, which, simply put, consists of an RNA part and a protein. It works as a molecular scissor that can perform targeted cuts followed by repairs in and around the genes of interest to attain favorable translational outcomes. We focused on summarizing recent studies using CRISPR-Cas9 technology in diagnosing and treating cardiovascular disease. These studies are primarily experimental and limited to animal models. However, their results are promising enough to anticipate that this technology will undoubtedly be available in clinical medicine in the coming years. CRISPR-Cas9-mediated gene editing has been used to study and potentially treat congenital heart disease, hyperlipidemias, arrhythmogenic cardiomyopathies, and the prevention of ischemia-reperfusion injury. Despite the current progress, we recognize the several challenges this technology faces, including funding for research, improving precision and reproducible results for human subjects, and establishing protocols for ethical compliance so that it is acceptable to the scientific community and the general public.

Precision Hypertension

Hypertension affects >1 billion people worldwide. Complications of hypertension include stroke, renal failure, cardiac hypertrophy, myocardial infarction, and cardiac failure. Despite the development of various antihypertensive drugs, the number of people with uncontrolled hypertension continues to rise. While the lack of compliance associated with frequent side effects to medication is a contributory issue, there has been a failure to consider the diverse nature of hypertensive populations. Instead, we propose that hypertension can only be truly managed by precision. A precision medicine approach would consider each patient's unique factors. In this review, we discuss the progress toward precision medicine for hypertension with more predictiveness and individualization of treatment. We will highlight the advances in data science, omics (genomics, metabolomics, proteomics, etc), artificial intelligence, gene therapy, and gene editing and their application to precision hypertension.

Past, present, and future of CRISPR genome editing technologies

Genome editing has been a transformative force in the life sciences and human medicine, offering unprecedented opportunities to dissect complex biological processes and treat the underlying causes of many genetic diseases. CRISPR-based technologies, with their remarkable efficiency and easy programmability, stand at the forefront of this revolution. In this Review, we discuss the current state of CRISPR gene editing technologies in both research and therapy, highlighting limitations that constrain them and the technological innovations that have been developed in recent years to address them. Additionally, we examine and summarize the current landscape of gene editing applications in the context of human health and therapeutics. Finally, we outline potential future developments that could shape gene editing technologies and their applications in the coming years.

RNA Therapeutics for the Cardiovascular System

RNA therapeutics hold significant promise in the treatment of cardiovascular diseases. RNAs are biologically diverse and functionally specific and can be used for gain- or loss-of-function purposes. The effectiveness of mRNA-based vaccines in the recent COVID-19 pandemic has undoubtedly proven the benefits of an RNA-based approach. RNA-based therapies are becoming more common as a treatment modality for cardiovascular disease. This is most evident in hypertension where several small interfering RNA-based drugs have proven to be effective in managing high blood pressure in several clinical trials. As befits a rapidly burgeoning field, there is significant interest in other classes of RNA. Revascularization of the infarcted heart through an mRNA drug is under clinical investigation. mRNA technology may provide the platform for the expression of paracrine factors for myocardial protection and regeneration. Emergent technologies on the basis of microRNAs and gene editing are tackling complex diseases in a novel fashion. RNA-based gene editing offers hope of permanent cures for monogenic cardiovascular diseases, and long-term control of complex diseases such as essential hypertension, as well. Likewise, microRNAs are proving effective in regenerating cardiac muscle. The aim of this review is to provide an overview of the current landscape of RNA-based therapies for the treatment of cardiovascular disease. The review describes the large number of RNA molecules that exist with a discussion of the clinical development of each RNA type. In addition, the review also presents a number of avenues for future development.

An Update on the Application of CRISPR Technology in Clinical Practice

The CRISPR/Cas system, an innovative gene-editing tool, is emerging as a promising technique for genome modifications. This straightforward technique was created based on the prokaryotic adaptive immune defense mechanism and employed in the studies on human diseases that proved enormous therapeutic potential. A genetically unique patient mutation in the process of gene therapy can be corrected by the CRISPR method to treat diseases that traditional methods were unable to cure. However, introduction of CRISPR/Cas9 into the clinic will be challenging because we still need to improve the technology's effectiveness, precision, and applications. In this review, we first describe the function and applications of the CRISPR-Cas9 system. We next delineate how this technology could be utilized for gene therapy of various human disorders, including cancer and infectious diseases and highlight the promising examples in the field. Finally, we document current challenges and the potential solutions to overcome these obstacles for the effective use of CRISPR-Cas9 in clinical practice.

Advancements in CRISPR-Based Therapies for Genetic Modulation in Neurodegenerative Disorders

Neurodegenerative disorders pose significant challenges in the realm of healthcare, as these conditions manifest in complex, multifaceted ways, often attributed to genetic anomalies. With the emergence of CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) technology, a new frontier has been unveiled in the quest for targeted, precise genetic manipulation. This abstract explores the recent advancements and potential applications of CRISPR-based therapies in addressing genetic components contributing to various neurodegenerative disorders. The review delves into the foundational principles of CRISPR technology, highlighting its unparalleled ability to edit genetic sequences with unprecedented precision. In addition, it talks about the latest progress in using CRISPR to target specific genetic mutations linked to neurodegenerative diseases like Huntington's disease, Alzheimer's disease, amyotrophic lateral sclerosis (ALS), and Parkinson's disease. It talks about the most important studies and trials that show how well and safely CRISPR-based therapies work. This shows how this technology can change genetic variants that cause diseases. Notably, the discussion emphasizes the challenges and ethical considerations associated with the implementation of CRISPR in clinical settings, including off-target effects, delivery methods, and long-term implications. Furthermore, the article explores the prospects and potential hurdles in the widespread application of CRISPR technology for treating neurodegenerative disorders. It touches upon the need for continued research, improved delivery mechanisms, and ethical frameworks to ensure responsible and equitable access to these groundbreaking therapies.

CRISPR-Cas9 Gene Editing: Curing Genetic Diseases by Inherited Epigenetic Modifications

Introduction  CRISPR-Cas9 gene editing, leveraging bacterial defense mechanisms, offers precise DNA modifications, holding promise in curing genetic diseases. This review critically assesses its potential, analyzing evidence on therapeutic applications, challenges, and future prospects. Examining diverse genetic disorders, it evaluates efficacy, safety, and limitations, emphasizing the need for a thorough understanding among medical professionals and researchers. Acknowledging its transformative impact, a systematic review is crucial for informed decision-making, responsible utilization, and guiding future research to unlock CRISPR-Cas9's full potential in realizing the cure for genetic diseases. Methods  A comprehensive literature search across PubMed, Scopus, and the Web of Science identified studies applying CRISPR-Cas9 gene editing for genetic diseases, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Inclusion criteria covered in vitro and in vivo models targeting various genetic diseases with reported outcomes on disease modification or potential cure. Quality assessment revealed a generally moderate to high risk of bias. Heterogeneity prevented quantitative meta-analysis, prompting a narrative synthesis of findings. Discussion  CRISPR-Cas9 enables precise gene editing, correcting disease-causing mutations and offering hope for previously incurable genetic conditions. Leveraging inherited epigenetic modifications, it not only fixes mutations but also restores normal gene function and controls gene expression. The transformative potential of CRISPR-Cas9 holds promise for personalized treatments, improving therapeutic outcomes, but ethical considerations and safety concerns must be rigorously addressed to ensure responsible and safe application, especially in germline editing with potential long-term implications.

Dystrophin- and Utrophin-Based Therapeutic Approaches for Treatment of Duchenne Muscular Dystrophy: A Comparative Review

Duchenne muscular dystrophy is a devastating disease that leads to progressive muscle loss and premature death. While medical management focuses mostly on symptomatic treatment, decades of research have resulted in first therapeutics able to restore the affected reading frame of dystrophin transcripts or induce synthesis of a truncated dystrophin protein from a vector, with other strategies based on gene therapy and cell signaling in preclinical or clinical development. Nevertheless, recent reports show that potentially therapeutic dystrophins can be immunogenic in patients. This raises the question of whether a dystrophin paralog, utrophin, could be a more suitable therapeutic protein. Here, we compare dystrophin and utrophin amino acid sequences and structures, combining published data with our extended in silico analyses. We then discuss these results in the context of therapeutic approaches for Duchenne muscular dystrophy. Specifically, we focus on strategies based on delivery of micro-dystrophin and micro-utrophin genes with recombinant adeno-associated viral vectors, exon skipping of the mutated dystrophin pre-mRNAs, reading through termination codons with small molecules that mask premature stop codons, dystrophin gene repair by clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (CRISPR/Cas9)-mediated genetic engineering, and increasing utrophin levels. Our analyses highlight the importance of various dystrophin and utrophin domains in Duchenne muscular dystrophy treatment, providing insights into designing novel therapeutic compounds with improved efficacy and decreased immunoreactivity. While the necessary actin and β-dystroglycan binding sites are present in both proteins, important functional distinctions can be identified in these domains and some other parts of truncated dystrophins might need redesigning due to their potentially immunogenic qualities. Alternatively, therapies based on utrophins might provide a safer and more effective approach.

Clinical applications of the CRISPR/Cas9 genome-editing system: Delivery options and challenges in precision medicine

CRISPR/Cas9 is an effective gene editing tool with broad applications for the prevention or treatment of numerous diseases. It depends on CRISPR (clustered regularly interspaced short palindromic repeats) as a bacterial immune system and plays as a gene editing tool. Due to the higher specificity and efficiency of CRISPR/Cas9 compared to other editing approaches, it has been broadly investigated to treat numerous hereditary and acquired illnesses, including cancers, hemolytic diseases, immunodeficiency disorders, cardiovascular diseases, visual maladies, neurodegenerative conditions, and a few X-linked disorders. CRISPR/Cas9 system has been used to treat cancers through a variety of approaches, with stable gene editing techniques. Here, the applications and clinical trials of CRISPR/Cas9 in various illnesses are described. Due to its high precision and efficiency, CRISPR/Cas9 strategies may treat gene-related illnesses by deleting, inserting, modifying, or blocking the expression of specific genes. The most challenging barrier to the in vivo use of CRISPR/Cas9 like off-target effects will be discussed. The use of transfection vehicles for CRISPR/Cas9, including viral vectors (such as an Adeno-associated virus (AAV)), and the development of non-viral vectors is also considered.

CRISPRi gene modulation and all-optical electrophysiology in post-differentiated human iPSC-cardiomyocytes

Uncovering gene-phenotype relationships can be enabled by precise gene modulation in human induced pluripotent stem-cell-derived cardiomyocytes (iPSC-CMs) and follow up phenotyping using scalable all-optical electrophysiology platforms. Such efforts towards human functional genomics can be aided by recent CRISPR-derived technologies for reversible gene inhibition or activation (CRISPRi/a). We set out to characterize the performance of CRISPRi in post-differentiated iPSC-CMs, targeting key cardiac ion channel genes, KCNH2, KCNJ2, and GJA1, and providing a multiparametric quantification of the effects on cardiac repolarization, stability of the resting membrane potential and conduction properties using all-optical tools. More potent CRISPRi effectors, e.g., Zim3, and optimized viral delivery led to improved performance on par with the use of CRISPRi iPSC lines. Confirmed mild yet specific phenotype changes when CRISPRi is deployed in non-dividing differentiated heart cells is an important step towards more holistic pre-clinical cardiotoxicity testing and for future therapeutic use in vivo.

In Vitro Prostate Cancer Treatment via CRISPR-Cas9 Gene Editing Facilitated by Polyethyleneimine-Derived Graphene Quantum Dots

CRISPR-Cas9 is a programmable gene editing tool with a promising potential for cancer gene therapy. This therapeutic function is enabled in the present work via the non-covalent delivery of CRISPR ribonucleic protein (RNP) by cationic glucosamine/PEI-derived graphene quantum dots (PEI-GQD) that aid in overcoming physiological barriers and tracking genes of interest. PEI-GQD/RNP complex targeting the TP53 mutation overexpressed in ~50% of cancers successfully produces its double-stranded breaks in solution and in PC3 prostate cancer cells. Restoring this cancer "suicide" gene can promote cellular repair pathways and lead to cancer cell apoptosis. Its repair to the healthy form performed by simultaneous PEI-GQD delivery of CRISPR RNP and a gene repair template leads to a successful therapeutic outcome: 40% apoptotic cancer cell death, while having no effect on non-cancerous HeK293 cells. The translocation of PEI-GQD/RNP complex into PC3 cell cytoplasm is tracked via GQD intrinsic fluorescence, while EGFP-tagged RNP is detected in the cell nucleus, showing the successful detachment of the gene editing tool upon internalization. Using GQDs as non-viral delivery and imaging agents for CRISPR-Cas9 RNP sets the stage for image-guided cancer-specific gene therapy.

RNA-based medicine: from molecular mechanisms to therapy

RNA-based therapeutics have the potential to revolutionize the treatment and prevention of human diseases. While early research faced setbacks, it established the basis for breakthroughs in RNA-based drug design that culminated in the extraordinarily fast development of mRNA vaccines to combat the COVID-19 pandemic. We have now reached a pivotal moment where RNA medicines are poised to make a broad impact in the clinic. In this review, we present an overview of different RNA-based strategies to generate novel therapeutics, including antisense and RNAi-based mechanisms, mRNA-based approaches, and CRISPR-Cas-mediated genome editing. Using three rare genetic diseases as examples, we highlight the opportunities, but also the challenges to wide-ranging applications of this class of drugs.

CRISPR/Cas9 technology: applications in oocytes and early embryos

CRISPR/Cas9, a highly versatile genome-editing tool, has garnered significant attention in recent years. Despite the unique characteristics of oocytes and early embryos compared to other cell types, this technology has been increasing used in mammalian reproduction. In this comprehensive review, we elucidate the fundamental principles of CRISPR/Cas9-related methodologies and explore their wide-ranging applications in deciphering molecular intricacies during oocyte and early embryo development as well as in addressing associated diseases. However, it is imperative to acknowledge the limitations inherent to these technologies, including the potential for off-target effects, as well as the ethical concerns surrounding the manipulation of human embryos. Thus, a judicious and thoughtful approach is warranted. Regardless of these challenges, CRISPR/Cas9 technology undeniably represents a formidable tool for genome and epigenome manipulation within oocytes and early embryos. Continuous refinements in this field are poised to fortify its future prospects and applications.

CRISPR-Cas9 homology-independent targeted integration of exons 1-19 restores full-length dystrophin in mice

Duchenne muscular dystrophy is an X-linked disorder typically caused by out-of-frame mutations in the DMD gene. Most of these are deletions of one or more exons, which can theoretically be corrected through CRISPR-Cas9-mediated knockin. Homology-independent targeted integration is a mechanism for achieving such a knockin without reliance on homology-directed repair pathways, which are inactive in muscle. We designed a system based on insertion into intron 19 of a DNA fragment containing a pre-spliced mega-exon encoding DMD exons 1-19, along with the MHCK7 promoter, and delivered it via a pair of AAV9 vectors in mice carrying a Dmd exon 2 duplication. Maximal efficiency was achieved using a Cas9:donor adeno-associated virus (AAV) ratio of 1:5, with Cas9 under the control of the SPc5-12 promoter. This approach achieved editing of 1.4% of genomes in the heart, leading to 30% correction at the transcript level and restoration of 11% of normal dystrophin levels. Treatment efficacy was lower in skeletal muscles. Sequencing additionally revealed integration of fragmentary and recombined AAV genomes at the target site. These data provide proof of concept for a gene editing system that could restore full-length dystrophin in individuals carrying mutations upstream of intron 19, accounting for approximately 25% of Duchenne muscular dystrophy patients.

CRISPR-Cas Technology as a Revolutionary Genome Editing tool: Mechanisms and Biomedical Applications

Programmable nucleases are powerful genomic tools for precise genome editing. These tools precisely recognize, remove, or change DNA at a defined site, thereby, stimulating cellular DNA repair pathways that can cause mutations or accurate replacement or deletion/insertion of a sequence. CRISPR-Cas9 system is the most potent and useful genome editing technique adapted from the defense immune system of certain bacteria and archaea against viruses and phages. In the past decade, this technology made notable progress, and at present, it has largely been used in genome manipulation to make precise gene editing in plants, animals, and human cells. In this review, we aim to explain the basic principle, mechanisms of action, and applications of this system in different areas of medicine, with emphasizing on the detection and treatment of parasitic diseases.

En route towards a personalized medicine approach: Innovative therapeutic modalities for connective tissue disorders

Connective tissue disorders can be caused by pathogenic variants (mutations) in genes encoding extracellular matrix (ECM) proteins. Such disorders typically manifest during development or postnatal growth and result in significant morbidity and mortality. The development of curative treatments for connective tissue disorders is hampered in part by the inability of many mature connective tissues to efficiently regenerate. To be most effective, therapeutic strategies designed to preserve or restore tissue function will likely need to be initiated during phases of significant endogenous connective tissue remodeling and organ sculpting postnatally and directly target the underlying ECM protein mutations. With recent advances in whole exome sequencing, in-vitro and in-vivo disease modeling, and the development of mutation-specific molecular therapeutic modalities, it is now feasible to directly correct disease-causing mutations underlying connective tissue disorders and ameliorate their pathogenic consequences. These technological advances may lead to potentially curative personalized medicine approaches for connective tissue disorders that have previously been considered incurable. In this review, we highlight innovative therapeutic modalities including gene replacement, exon skipping, DNA/mRNA editing, and pharmacological approaches that were used to preserve or restore tissue function in the context of connective tissue disorders. Inherent to a successful application of these approaches is the need to deepen the understanding of mechanisms that regulate ECM formation and homeostasis, and to decipher how individual mutations in ECM proteins compromise ECM and connective tissue development and function.