Retinal gene therapy with adeno-associated viral (AAV) vectors holds promises for treating inherited and noninherited diseases of the eye. Although clinical data suggest that retinal gene therapy is ...safe and effective, delivery of large genes is hindered by the limited AAV cargo capacity. Protein trans-splicing mediated by split inteins is used by single-cell organisms to reconstitute proteins. Here, we show that delivery of multiple AAV vectors each encoding one of the fragments of target proteins flanked by short split inteins results in protein trans-splicing and full-length protein reconstitution in the retina of mice and pigs and in human retinal organoids. The reconstitution of large therapeutic proteins using this approach improved the phenotype of two mouse models of inherited retinal diseases. Our data support the use of split intein-mediated protein trans-splicing in combination with AAV subretinal delivery for gene therapy of inherited blindness due to mutations in large genes.
The expansion of the CRISPR-Cas toolbox is highly needed to accelerate the development of therapies for genetic diseases. Here, through the interrogation of a massively expanded repository of ...metagenome-assembled genomes, mostly from human microbiomes, we uncover a large variety (n = 17,173) of type II CRISPR-Cas loci. Among these we identify CoCas9, a strongly active and high-fidelity nuclease with reduced molecular size (1004 amino acids) isolated from an uncultivated Collinsella species. CoCas9 is efficiently co-delivered with its sgRNA through adeno associated viral (AAV) vectors, obtaining efficient in vivo editing in the mouse retina. With this study we uncover a collection of previously uncharacterized Cas9 nucleases, including CoCas9, which enriches the genome editing toolbox.
The paucity of evidence-based data on formulation characteristics preferred by the children is known to limit the design of tailored paediatric dosage forms. The European Paediatric Translational ...Research Infrastructure (EPTRI) commissioned a study to evaluate children’s dosage forms perceived preferences in some European countries and explore the feasibility of using the young persons advisory groups (YPAGs) to involve children in formulation research. An online, age-adapted survey was developed and translated into six languages. The survey link was disseminated across seven European countries: Albania, Italy, the Netherlands, and Dutch-speaking part of Belgium, Romania, Spain, and the United Kingdom. Respondents’ (n = 1172) perceived preferences for oral dosage forms primarily differed based on age, health status, and experience. Conventional dosage forms, i.e., liquid (35%), tablets (19%), and capsules (14%), were the most selected. Liquid was widely selected by children less than 12 years and by those healthy and taking medicines rarely. Monolithic solid forms were mostly chosen by adolescents and by children with a chronic disease taking medicines frequently. There was a clear lack of familiarity with more novel dosage forms (e.g., orodispersible films and granules). Noteworthy, granules were not appreciated, particularly by adolescents (52.8%). To rationalise the creation of paediatric formulations, it is important to involve children as active stakeholders and to apply tools assessing children’s perspectives on medicines to inform acceptable dosage form development from the start.
Transcription factors (TFs) operate by the combined activity of their DNA-binding domains (DBDs) and effector domains (EDs) enabling the coordination of gene expression on a genomic scale. Here we ...show that in vivo delivery of an engineered DNA-binding protein uncoupled from the repressor domain can produce efficient and gene-specific transcriptional silencing. To interfere with RHODOPSIN (RHO) gain-of-function mutations we engineered the ZF6-DNA-binding protein (ZF6-DB) that targets 20 base pairs (bp) of a RHOcis-regulatory element (CRE) and demonstrate Rho specific transcriptional silencing upon adeno-associated viral (AAV) vector-mediated expression in photoreceptors. The data show that the 20 bp-long genomic DNA sequence is necessary for RHO expression and that photoreceptor delivery of the corresponding cognate synthetic trans-acting factor ZF6-DB without the intrinsic transcriptional repression properties of the canonical ED blocks Rho expression with negligible genome-wide transcript perturbations. The data support DNA-binding-mediated silencing as a novel mode to treat gain-of-function mutations.
Development of specific medical devices (MDs) is required to meet the healthcare needs of children and young people (CYP). In this context, MD development should address changes in growth and ...psychosocial maturation, physiology, and pathophysiology, and avoid inappropriate repurposing of adult technologies. Underpinning the development of MD for CYP is the need to ensure MD safety and effectiveness through pediatric MD-specific regulations. Contrary to current perceptions of limited market potential, the global pediatric healthcare market is expected to generate around USD 15,984 million by 2025. There are 1.8 billion young people in the world today; 40% of the global population is under 24, creating significant future healthcare market opportunities. This review highlights a number of technology areas that have led to successful pediatric MD, including 3D printing, advanced materials, drug delivery, and diagnostic imaging. To ensure the targeted development of MD for CYP, collaboration across multiple professional disciplines is required, facilitated by a platform to foster collaboration and drive innovation. The European Pediatric Translational Research Infrastructure (EPTRI) will be established as the European platform to support collaboration, including the life sciences industrial sector, to identify unmet needs in child health and support the development, adoption, and commercialization of pediatric MDs.
Split intein-mediated protein
trans-
splicing expands AAV transfer capacity, thus overcoming the limited AAV cargo. However, non-mammalian inteins persist as
trans-
splicing by-products, and this ...could raise safety concerns for AAV intein clinical applications. In this study, we tested the ability of several degrons to selectively decrease levels of inteins after protein
trans-
splicing and found that a version of
E. coli
dihydrofolate reductase, which we have shortened to better fit into the AAV vector, is the most effective. We show that subretinal administration of AAV intein armed with this short degron is both safe and effective in a mouse model of Stargardt disease (STGD1), which is the most common form of inherited macular degeneration in humans. This supports the use of optimized AAV intein for gene therapy of both STGD1 and other conditions that require transfer of large genes.
Intein-mediated protein
trans
-splicing (PTS) expands AAV gene transfer capacity. However, non-mammalian inteins persist as
trans
-splicing by-products. Here, we show that ecDHFR selectively degrades inteins after PTS and that AAV intein vectors armed with this degron are both safe and effective in the retina of a mouse model of genetic blindness.
PedCRIN is a Horizon 2020 project aimed to develop a paediatric component of ECRIN (European Clinical Research Infrastructure Network) including tools supporting the conduct of neonatal and ...paediatric trials.
A structured, cross-sectional, closed-ended questionnaire was electronically administered from April to May 2017 to stakeholders involved in paediatric clinical research to capture their needs to receive infrastructural support to cover specific research gaps. The questionnaire included 6 headings and 29 subheadings. Each item was evaluated using a Likert-scale.
147 questionnaires were returned (response rate of 24.6%). The application of innovative study design and the preparation of protocols for paediatric interventional clinical trials had the highest frequency of high need for support (123 and 117 respondents, respectively). Similarly, the identification and applications to relevant calls for funding was acknowledged as an area in which support is needed (123 respondents declaring high need).
In 14 out of 29 activities, need for support was significantly higher in the respondents not being part of a Paediatric Research Network or Consortium (especially for regulatory expertise, pharmacovigilance and GCP training).
Conclusions: These results document that the achievement of PedCRIN objectives would greatly advantage the paediatric research community.
Development of age appropriate medicines for children is one of the major challenges of our century. Historically, research of new paediatric drugs has been neglected due to poor industrial interest ...and limited public and private investments. The ID-EPTRI project is aimed to bridge the existing gaps in paediatric medicine that stop the progress from early stage drug development phases to be translated into paediatric use of medicines, through a new paediatric Research Infrastructure. To reach this goal, EPTRI has developed and disseminated a survey in order to identify the gaps and map the competences of the excellence of the paediatric research in pan-European countries that will be the potential service providers of the new Research Infrastructure. EPTRI will network all the available competences and technologies useful to the paediatric research, creating an open science space allowing top-level researchers to work together.
Abstract
The lack of paediatric medicines, including innovative and advanced ones, is a long-lasting and well-known problem at European and international levels. Despite the existing legal frameworks ...and incentives, children remain deprived of many kinds of therapy because of challenges faced in appropriately study and tailoring medicinal and other products for them. In this context, the necessity to foster paediatric research addressing unsolved and uncovered issues within a 'translational approach' has appeared. This article, after having clarified the concept of translational research in the perspective of the establishment of a European paediatric research infrastructure (RI), will identify and point out ethical, legal and regulatory issues particularly relevant in a children's rights perspective. It concludes asking for the setting up of an adequate model of governance within a future RI, including adequate and independent ethical oversight and a pluridisciplinary common service dealing with ethical, legal and societal issues relevant for children.
Split intein-mediated protein trans-splicing expands AAV transfer capacity, thus overcoming the limited AAV cargo. However, non-mammalian inteins persist as trans-splicing by-products, and this could ...raise safety concerns for AAV intein clinical applications. In this study, we tested the ability of several degrons to selectively decrease levels of inteins after protein trans-splicing and found that a version of E. coli dihydrofolate reductase, which we have shortened to better fit into the AAV vector, is the most effective. We show that subretinal administration of AAV intein armed with this short degron is both safe and effective in a mouse model of Stargardt disease (STGD1), which is the most common form of inherited macular degeneration in humans. This supports the use of optimized AAV intein for gene therapy of both STGD1 and other conditions that require transfer of large genes.
Display omitted
Intein-mediated protein trans-splicing (PTS) expands AAV gene transfer capacity. However, non-mammalian inteins persist as trans-splicing by-products. Here, we show that ecDHFR selectively degrades inteins after PTS and that AAV intein vectors armed with this degron are both safe and effective in the retina of a mouse model of genetic blindness.
PDF
