Genome editing in the treatment of ocular diseases

Bibliometric and visualized analysis of cancer nanomedicine from 2013 to 2023

Cancer nanomedicine has been an emerging field for drug development against malignant tumors during the past three decades. A bibliometric analysis was performed to characterize the current international trends and present visual representations of the evolution and emerging trends in the research and development of nanocarriers for cancer treatment. This study employed bibliometric analysis and visualization techniques to analyze the literature on antitumor nanocarriers published between 2013 and 2023. A total of 98,980 articles on antitumor nanocarriers were retrieved from the Web of Science Core Collection (WoSCC) database and analyzed using the Citespace software for specific characteristics such as publication year, countries/regions, organizations, keywords, and references. Network visualization was constructed by VOSviewer and Citespace. From 2013 to 2023, the annual global publications increased 7.39 times, from 1851 to 13,683. People's Republic of China (2588 publications) was the most productive country. Chinese Academy of Sciences (298 publications) was the most productive organization. The top 5 high-frequency keywords were "nanoparticles," "drug delivery," "nanomedicine," "cancer," and "nanocarriers." The keywords with the strongest citation bursts recently were "cancer immunotherapy," "microenvironment," "antitumor immunity," etc., which indicated the emerging frontiers of antitumor nanomedicine. The co-occurrence cluster analysis of the keywords formed 6 clusters, and most of the top 10 publications by citation counts focused on cluster #1 (nanocarriers) and cluster #2 (cancer immunotherapy). We further provided insightful discussions into the identified subtopics to help researchers gain more details of current trends and hotspots in this field. The present study processes a macro-level literature analysis of antitumor nanocarriers and provides new perspectives and research directions for future development in cancer nanomedicine.

In Silico CRISPR-Cas-Mediated Base Editing Strategies for Early-Onset, Severe Cone-Rod Retinal Degeneration in Three Crumbs homolog 1 Patients, including the Novel Variant c.2833G>A

Pathogenic variants in the Crumbs homolog 1 (CRB1) gene lead to severe, childhood-onset retinal degeneration leading to blindness in early adulthood. There are no approved therapies, and traditional adeno-associated viral vector-based gene therapy approaches are challenged by the existence of multiple CRB1 isoforms. Here, we describe three CRB1 variants, including a novel, previously unreported variant that led to retinal degeneration. We offer a CRISPR-Cas-mediated DNA base editing strategy as a potential future therapeutic approach. This study is a retrospective case series. Clinical and genetic assessments were performed, including deep phenotyping by retinal imaging. In silico analyses were used to predict the pathogenicity of the novel variant and to determine whether the variants are amenable to DNA base editing strategies. Case 1 was a 24-year-old male with cone-rod dystrophy and retinal thickening typical of CRB1 retinopathy. He had a relatively preserved central outer retinal structure and a best corrected visual acuity (BCVA) of 60 ETDRS letters in both eyes. Genetic testing revealed compound heterozygous variants in exon 9: c.2843G>A, p.(Cys948Tyr) and a novel variant, c.2833G>A, p.(Gly945Arg), which was predicted to likely be pathogenic by an in silico analysis. Cases 2 and 3 were two brothers, aged 20 and 24, who presented with severe cone-rod dystrophy and a significant disruption of the outer nuclear layers. The BCVA was reduced to hand movements in both eyes in Case 2 and to 42 ETDRS letters in both eyes in Case 3. Case 2 was also affected with marked cystoid macular lesions, which are common in CRB1 retinopathy, but responded well to treatment with oral acetazolamide. Genetic testing revealed two c.2234C>T, p.(Thr745Met) variants in both brothers. As G-to-A and C-to-T variants, all three variants are amenable to adenine base editors (ABEs) targeting the forward strand in the Case 1 variants and the reverse strand in Cases 2 and 3. Available PAM sites were detected for KKH-nSaCas9-ABE8e for the c.2843G>A variant, nSaCas9-ABE8e and KKH-nSaCas9-ABE8e for the c.2833G>A variant, and nSpCas9-ABE8e for the c.2234C>T variant. In this case series, we report three pathogenic CRB1 variants, including a novel c.2833G>A variant associated with early-onset cone-rod dystrophy. We highlight the severity and rapid progression of the disease and offer ABEs as a potential future therapeutic approach for this devastating blinding condition.

Epigenetic and gene therapy in human and veterinary medicine

Gene therapy is a focus of interest in both human and veterinary medicine, especially in recent years due to the potential applications of CRISPR/Cas9 technology. Another relatively new approach is that of epigenetic therapy, which involves an intervention based on epigenetic marks, including DNA methylation, histone post-translational modifications, and post-transcription modifications of distinct RNAs. The epigenome results from enzymatic reactions, which regulate gene expression without altering DNA sequences. In contrast to conventional CRISP/Cas9 techniques, the recently established methodology of epigenetic editing mediated by the CRISPR/dCas9 system is designed to target specific genes without causing DNA breaks. Both natural epigenetic processes and epigenetic editing regulate gene expression and thereby contribute to maintaining the balance between physiological functions and pathophysiological states. From this perspective, knowledge of specific epigenetic marks has immense potential in both human and veterinary medicine. For instance, the use of epigenetic drugs (chemical compounds with therapeutic potential affecting the epigenome) seems to be promising for the treatment of cancer, metabolic, and infectious diseases. Also, there is evidence that an epigenetic diet (nutrition-like factors affecting epigenome) should be considered as part of a healthy lifestyle and could contribute to the prevention of pathophysiological processes. In summary, epigenetic-based approaches in human and veterinary medicine have increasing significance in targeting aberrant gene expression associated with various diseases. In this case, CRISPR/dCas9, epigenetic targeting, and some epigenetic nutrition factors could contribute to reversing an abnormal epigenetic landscape to a healthy physiological state.

A New Generation of Gene Therapies as the Future of Wet AMD Treatment

Age-related macular degeneration (AMD) is an eye disease and the most common cause of vision loss in the Western World. In its advanced stage, AMD occurs in two clinically distinguished forms, dry and wet, but only wet AMD is treatable. However, the treatment based on repeated injections with vascular endothelial growth factor A (VEGFA) antagonists may at best stop the disease progression and prevent or delay vision loss but without an improvement of visual dysfunction. Moreover, it is a serious mental and financial burden for patients and may be linked with some complications. The recent first success of intravitreal gene therapy with ADVM-022, which transformed retinal cells to continuous production of aflibercept, a VEGF antagonist, after a single injection, has opened a revolutionary perspective in wet AMD treatment. Promising results obtained so far in other ongoing clinical trials support this perspective. In this narrative/hypothesis review, we present basic information on wet AMD pathogenesis and treatment, the concept of gene therapy in retinal diseases, update evidence on completed and ongoing clinical trials with gene therapy for wet AMD, and perspectives on the progress to the clinic of "one and done" therapy for wet AMD to replace a lifetime of injections. Gene editing targeting the VEGFA gene is also presented as another gene therapy strategy to improve wet AMD management.

Unraveling the Genetic Landscape of Neurological Disorders: Insights into Pathogenesis, Techniques for Variant Identification, and Therapeutic Approaches

Genetic abnormalities play a crucial role in the development of neurodegenerative disorders (NDDs). Genetic exploration has indeed contributed to unraveling the molecular complexities responsible for the etiology and progression of various NDDs. The intricate nature of rare and common variants in NDDs contributes to a limited understanding of the genetic risk factors associated with them. Advancements in next-generation sequencing have made whole-genome sequencing and whole-exome sequencing possible, allowing the identification of rare variants with substantial effects, and improving the understanding of both Mendelian and complex neurological conditions. The resurgence of gene therapy holds the promise of targeting the etiology of diseases and ensuring a sustained correction. This approach is particularly enticing for neurodegenerative diseases, where traditional pharmacological methods have fallen short. In the context of our exploration of the genetic epidemiology of the three most prevalent NDDs-amyotrophic lateral sclerosis, Alzheimer's disease, and Parkinson's disease, our primary goal is to underscore the progress made in the development of next-generation sequencing. This progress aims to enhance our understanding of the disease mechanisms and explore gene-based therapies for NDDs. Throughout this review, we focus on genetic variations, methodologies for their identification, the associated pathophysiology, and the promising potential of gene therapy. Ultimately, our objective is to provide a comprehensive and forward-looking perspective on the emerging research arena of NDDs.