192 research outputs found
Antisense-induced exon skipping for duplications in Duchenne muscular dystrophy
<p>Abstract</p> <p>Background</p> <p>Antisense-mediated exon skipping is currently one of the most promising therapeutic approaches for Duchenne muscular dystrophy (DMD). Using antisense oligonucleotides (AONs) targeting specific exons the DMD reading frame is restored and partially functional dystrophins are produced. Following proof of concept in cultured muscle cells from patients with various deletions and point mutations, we now focus on single and multiple exon duplications. These mutations are in principle ideal targets for this approach since the specific skipping of duplicated exons would generate original, full-length transcripts.</p> <p>Methods</p> <p>Cultured muscle cells from DMD patients carrying duplications were transfected with AONs targeting the duplicated exons, and the dystrophin RNA and protein were analyzed.</p> <p>Results</p> <p>For two brothers with an exon 44 duplication, skipping was, even at suboptimal transfection conditions, so efficient that both exons 44 were skipped, thus generating, once more, an out-of-frame transcript. In such cases, one may resort to multi-exon skipping to restore the reading frame, as is shown here by inducing skipping of exon 43 and both exons 44. By contrast, in cells from a patient with an exon 45 duplication we were able to induce single exon 45 skipping, which allowed restoration of wild type dystrophin. The correction of a larger duplication (involving exons 52 to 62), by combinations of AONs targeting the outer exons, appeared problematic due to inefficient skipping and mistargeting of original instead of duplicated exons.</p> <p>Conclusion</p> <p>The correction of DMD duplications by exon skipping depends on the specific exons targeted. Its options vary from the ideal one, restoring for the first time the true, wild type dystrophin, to requiring more 'classical' skipping strategies, while the correction of multi-exon deletions may need the design of tailored approaches.</p
Opportunities and challenges for antisense oligonucleotide therapies
Antisense oligonucleotide (AON) therapies involve short strands of modified nucleotides that target RNA in a sequence-specific manner, inducing targeted protein knockdown or restoration. Currently, 10 AON therapies have been approved in the United States and Europe. Nucleotides are chemically modified to protect AONs from degradation, enhance bioavailability and increase
A Randomized Greedy Algorithm for Near-Optimal Sensor Scheduling in Large-Scale Sensor Networks
We study the problem of scheduling sensors in a resource-constrained linear
dynamical system, where the objective is to select a small subset of sensors
from a large network to perform the state estimation task. We formulate this
problem as the maximization of a monotone set function under a matroid
constraint. We propose a randomized greedy algorithm that is significantly
faster than state-of-the-art methods. By introducing the notion of curvature
which quantifies how close a function is to being submodular, we analyze the
performance of the proposed algorithm and find a bound on the expected mean
square error (MSE) of the estimator that uses the selected sensors in terms of
the optimal MSE. Moreover, we derive a probabilistic bound on the curvature for
the scenario where{\color{black}{ the measurements are i.i.d. random vectors
with bounded norm.}} Simulation results demonstrate efficacy of the
randomized greedy algorithm in a comparison with greedy and semidefinite
programming relaxation methods
Antisense-Mediated RNA Targeting: Versatile and Expedient Genetic Manipulation in the Brain
A limiting factor in brain research still is the difficulty to evaluate in vivo the role of the increasing number of proteins implicated in neuronal processes. We discuss here the potential of antisense-mediated RNA targeting approaches. We mainly focus on those that manipulate splicing (exon skipping and exon inclusion), but will also briefly discuss mRNA targeting. Classic knockdown of expression by mRNA targeting is only one possible application of antisense oligonucleotides (AON) in the control of gene function. Exon skipping and inclusion are based on the interference of AONs with splicing of pre-mRNAs. These are powerful, specific and particularly versatile techniques, which can be used to circumvent pathogenic mutations, shift splice variant expression, knock down proteins, or to create molecular models using in-frame deletions. Pre-mRNA targeting is currently used both as a research tool, e.g., in models for motor neuron disease, and in clinical trials for Duchenne muscular dystrophy and amyotrophic lateral sclerosis. AONs are particularly promising in relation to brain research, as the modified AONs are taken up extremely fast in neurons and glial cells with a long residence, and without the need for viral vectors or other delivery tools, once inside the blood brain barrier. In this review we cover (1). The principles of antisense-mediated techniques, chemistry, and efficacy. (2) The pros and cons of AON approaches in the brain compared to other techniques of interfering with gene function, such as transgenesis and short hairpin RNAs, in terms of specificity of the manipulation, spatial, and temporal control over gene expression, toxicity, and delivery issues. (3) The potential applications for Neuroscience. We conclude that there is good evidence from animal studies that the central nervous system can be successfully targeted, but the potential of the diverse AON-based approaches appears to be under-recognized
Case report: the genetic diagnosis of duchenne muscular dystrophy in the Middle East
The timely and accurate genetic diagnosis of Duchenne muscular dystrophy (DMD) enables prompt initiation of disease management and genetic counseling and optimal patient care. Despite the existence of best practice guidelines for the diagnosis of DMD, implementation of these recommendations in different parts of the world is challenging. Here, we present 4 unique case studies which illustrate the different diagnostic pathways of patients with DMD in Middle Eastern countries and highlight region-specific challenges to achieving timely and accurate genetic diagnosis of DMD. A lack of disease awareness and consequential failure to recognize the signs and symptoms of DMD significantly contributed to the delayed diagnoses of these patients. Additional challenges included limited available funding for genetic testing and a lack of local specialist and genetic testing centers, causing patients and their families to travel vast distances for appointments in some countries. Earlier and more accurate genetic diagnosis of DMD in this region would allow patients to benefit from effective disease management, leading to improvements in health-related quality of life.Functional Genomics of Muscle, Nerve and Brain Disorder
Update on Standard Operating Procedures in Preclinical Research for DMD and SMA Report of TREAT-NMD Alliance Workshop, Schiphol Airport, 26 April 2015, The Netherlands
A workshop took place in 2015 to follow up TREAT-NMD activities dedicated to improving quality in the preclinical phase of drug development for neuromuscular diseases. In particular, this workshop adressed necessary future steps regarding common standard experimental protocols and the issue of improving the translatability of preclinical efficacy studies
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