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Journal of the American Society of... Jun 2018Podocyte loss and effacement of interdigitating podocyte foot processes are the major cause of a leaky filtration barrier and ESRD. Because the complex...
Podocyte loss and effacement of interdigitating podocyte foot processes are the major cause of a leaky filtration barrier and ESRD. Because the complex three-dimensional morphology of podocytes depends on the actin cytoskeleton, we studied the role in podocytes of the actin bundling protein palladin, which is highly expressed therein. We knocked down palladin in cultured podocytes by siRNA transfection or in zebrafish embryos by morpholino injection and studied the effects by immunofluorescence and live imaging. We also investigated kidneys of mice with podocyte-specific knockout of palladin (PodoPalld-/- mice) by immunofluorescence and ultrastructural analysis and kidney biopsy specimens from patients by immunostaining for palladin. Compared with control-treated podocytes, palladin-knockdown podocytes had reduced actin filament staining, smaller focal adhesions, and downregulation of the podocyte-specific proteins synaptopodin and -actinin-4. Furthermore, palladin-knockdown podocytes were more susceptible to disruption of the actin cytoskeleton with cytochalasin D, latrunculin A, or jasplakinolide and showed altered migration dynamics. In zebrafish embryos, palladin knockdown compromised the morphology and dynamics of epithelial cells at an early developmental stage. Compared with PodoPalld+/+ controls, PodoPalld-/- mice developed glomeruli with a disturbed morphology, an enlarged subpodocyte space, mild effacement, and significantly reduced expression of nephrin and vinculin. Furthermore, nephrotoxic serum injection led to significantly higher levels of proteinuria in PodoPalld-/- mice than in controls. Kidney biopsy specimens from patients with diabetic nephropathy and FSGS showed downregulation of palladin in podocytes as well. Palladin has an important role in podocyte function and .
Topics: Actins; Animals; Cytoskeletal Proteins; Cytoskeleton; Female; Focal Adhesions; Gene Expression; Gene Silencing; Humans; Kidney Glomerulus; Male; Mice, Knockout; Microfilament Proteins; Morpholinos; Phosphoproteins; Podocytes; RNA, Messenger; Vinculin; Zebrafish; Zebrafish Proteins
PubMed: 29720549
DOI: 10.1681/ASN.2017091039 -
Developmental Biology Oct 2022The impact of new technology can be appreciated by how broadly it is used. Investigators that previously relied only on pharmacological approaches or the use of...
The impact of new technology can be appreciated by how broadly it is used. Investigators that previously relied only on pharmacological approaches or the use of morpholino antisense oligonucleotide (MASO) technologies are now able to apply CRISPR-Cas9 to study biological problems in their model organism of choice much more effectively. The transitions to new CRISPR-based approaches could be enhanced, first, by standardized protocols and education in their applications. Here we summarize our results for optimizing the CRISPR-Cas9 technology in a sea urchin and a sea star, and provide advice on how to set up CRISPR-Cas9 experiments and interpret the results in echinoderms. Our goal through these protocols and sharing examples of success by other labs is to lower the activation barrier so that more laboratories can apply CRISPR-Cas9 technologies in these important animals.
Topics: Animals; CRISPR-Cas Systems; Gene Editing; Morpholinos; RNA, Guide, CRISPR-Cas Systems; Sea Urchins
PubMed: 35917936
DOI: 10.1016/j.ydbio.2022.07.008 -
Pediatric Pulmonology Oct 2020Neuromuscular cardiopulmonary medicine is entering a new and exciting phase, with studies that assess the respiratory effect of emerging genetic and molecular therapies.... (Review)
Review
Neuromuscular cardiopulmonary medicine is entering a new and exciting phase, with studies that assess the respiratory effect of emerging genetic and molecular therapies. In this year's neuromuscular Year in Review, we focus on Duchenne muscular dystrophy (DMD), reviewing studies that evaluate the respiratory effect of eteplirsen, the cardiopulmonary effects of ataluren, and a study comparing the use of spironolactone with eplerenone for the treatment of DMD-related cardiomyopathy.
Topics: Cardiomyopathies; Humans; Morpholinos; Muscular Dystrophy, Duchenne; Oxadiazoles; Spironolactone
PubMed: 32691988
DOI: 10.1002/ppul.24970 -
Indian Pediatrics Feb 2020Synthetic Antisense oligonucleotides (ASOs) are novel and efficient laboratory tools to regulate the expression of specific genes, and have only recently come into... (Review)
Review
Synthetic Antisense oligonucleotides (ASOs) are novel and efficient laboratory tools to regulate the expression of specific genes, and have only recently come into clinical use. These are synthetic single-stranded DNA analogs, whose sequence is complementary to a target nucleotide and alter protein synthesis by several mechanisms. We herein provide a primer on the topic for pediatricians, as this group of drugs is likely to see many more drugs for previously incurable diseases.
Topics: Adolescent; Child; Child, Preschool; Humans; Infant; Morpholinos; Muscular Atrophy, Spinal; Muscular Dystrophy, Duchenne; Oligonucleotides; Oligonucleotides, Antisense; Randomized Controlled Trials as Topic
PubMed: 32060244
DOI: No ID Found -
European Journal of Cell Biology Jun 2023Spinal muscular atrophy (SMA), the most common genetic cause of infantile death, is caused by a mutation in the survival of motor neuron 1 gene (SMN1), leading to the... (Review)
Review
Spinal muscular atrophy (SMA), the most common genetic cause of infantile death, is caused by a mutation in the survival of motor neuron 1 gene (SMN1), leading to the death of motor neurons and progressive muscle weakness. SMN1 normally produces an essential protein called SMN. Although humans possess a paralogous gene called SMN2, ∼90% of the SMN it produces is non-functional. This is due to a mutation in SMN2 that causes the skipping of a required exon during splicing of the pre-mRNA. The first treatment for SMA, nusinersen (brand name Spinraza), was approved by the FDA in 2016 and by the EMU in 2017. Nusinersen is an antisense oligonucleotide-based therapy that alters the splicing of SMN2 to make functional full-length SMN protein. Despite the recent advancements in antisense oligonucleotide therapy and SMA treatment development, nusinersen is faced with a multitude of challenges, such as intracellular and systemic delivery. In recent years, the use of peptide-conjugated phosphorodiamidate morpholino oligomers (PPMOs) in antisense therapy has gained interest. These are antisense oligonucleotides conjugated to cell-penetrating peptides such as Pips and DG9, and they have the potential to address the challenges associated with delivery. This review focuses on the historic milestones, development, current challenges, and future perspectives of antisense therapy for SMA.
Topics: Humans; Oligonucleotides, Antisense; Muscular Atrophy, Spinal; Morpholinos; Motor Neurons; RNA Splicing
PubMed: 37295266
DOI: 10.1016/j.ejcb.2023.151326 -
Cells Oct 2023Antisense oligonucleotide-based (ASO) therapeutics have emerged as a promising strategy for the treatment of human disorders. Charge-neutral PMOs have promising... (Review)
Review
Antisense oligonucleotide-based (ASO) therapeutics have emerged as a promising strategy for the treatment of human disorders. Charge-neutral PMOs have promising biological and pharmacological properties for antisense applications. Despite their great potential, the efficient delivery of these therapeutic agents to target cells remains a major obstacle to their widespread use. Cellular uptake of naked PMO is poor. Cell-penetrating peptides (CPPs) appear as a possibility to increase the cellular uptake and intracellular delivery of oligonucleotide-based drugs. Among these, the DG9 peptide has been identified as a versatile CPP with remarkable potential for enhancing the delivery of ASO-based therapeutics due to its unique structural features. Notably, in the context of phosphorodiamidate morpholino oligomers (PMOs), DG9 has shown promise in enhancing delivery while maintaining a favorable toxicity profile. A few studies have highlighted the potential of DG9-conjugated PMOs in DMD (Duchenne Muscular Dystrophy) and SMA (Spinal Muscular Atrophy), displaying significant exon skipping/inclusion and functional improvements in animal models. The article provides an overview of a detailed understanding of the challenges that ASOs face prior to reaching their targets and continued advances in methods to improve their delivery to target sites and cellular uptake, focusing on DG9, which aims to harness ASOs' full potential in precision medicine.
Topics: Animals; Humans; Oligonucleotides, Antisense; Cell-Penetrating Peptides; Oligonucleotides; Morpholinos; Muscular Dystrophy, Duchenne; Muscular Atrophy, Spinal
PubMed: 37830609
DOI: 10.3390/cells12192395 -
Current Protocols Feb 2023Phosphorodiamidate morpholino oligonucleotides (PMOs) are a successful class of antisense reagents that efficiently modulate gene expression. Because PMOs do not follow...
Phosphorodiamidate morpholino oligonucleotides (PMOs) are a successful class of antisense reagents that efficiently modulate gene expression. Because PMOs do not follow standard phosphoramidite chemistry, optimized synthetic protocols for these compounds are relatively scarce in the literature. This paper presents detailed protocols for synthesizing full-length PMOs using chlorophosphoramidate chemistry by manual solid-phase synthesis. We first describe the synthesis of Fmoc-protected morpholino hydroxyl monomers, and the corresponding chlorophosphoramidate monomers, from commercially available protected ribonucleosides. The new Fmoc chemistry necessitates the use of a milder base, such as N-ethylmorpholine (NEM), and coupling reagent, such as 5-(ethylthio)-1H-tetrazole (ETT), which are also tolerated for acid-sensitive trityl chemistry. These chlorophosphoramidate monomers are then employed for PMO synthesis in a manual solid-phase procedure using four sequential steps. The synthetic cycle for each nucleotide incorporation consists of (a) deblocking of the 3'-N protecting group using an acidic deblocking cocktail for trityl and base deblocking for Fmoc, (b) neutralization, (c) coupling in the presence of ETT and NEM, and (d) capping of the unreacted morpholine ring-amine. The method uses safe, stable, and inexpensive reagents, and the process is expected to be scalable. After full-length PMO synthesis and ammonia-mediated cleavage from the solid support and deprotection, a range of PMOs with different lengths can be obtained conveniently and efficiently with reproducible good yields. © 2023 Wiley Periodicals LLC. Basic Protocol 1: Synthesis of the novel Fmoc-protected morpholino monomers Basic Protocol 2: Synthesis of the phosphorylating reagent (N,N-dimethylphosphoramic dichloride) required for chlorophosphoramidate monomer synthesis Basic Protocol 3: Synthesis of chlorophosphoramidate monomers of Fmoc-protected morpholino monomers Basic Protocol 4: Solution-phase standardization of dimer and trimer PMO synthesis using Fmoc chemistry Basic Protocol 5: Solid-phase synthesis, purification, and characterization of full-length (25-mer) no-tail PMO using both trityl and Fmoc chemistry.
Topics: Morpholinos; Oligonucleotides, Antisense
PubMed: 36802170
DOI: 10.1002/cpz1.686 -
Developmental Cell Oct 2015For over 15 years, antisense morpholino oligonucleotides (MOs) have allowed developmental biologists to make key discoveries regarding developmental mechanisms in... (Review)
Review
For over 15 years, antisense morpholino oligonucleotides (MOs) have allowed developmental biologists to make key discoveries regarding developmental mechanisms in numerous model organisms. Recently, serious concerns have been raised as to the specificity of MO effects, and it has been recommended to discontinue their usage, despite the long experience of the scientific community with the MO tool in thousands of studies. Reviewing the many advantages afforded by MOs, we conclude that adequately controlled MOs should continue to be accepted as generic loss-of-function approach, as otherwise progress in developmental biology will greatly suffer.
Topics: Animals; Developmental Biology; Humans; Morpholinos; Oligonucleotides, Antisense; Zebrafish
PubMed: 26506304
DOI: 10.1016/j.devcel.2015.09.017 -
Journal of Biosciences 2023Duchenne muscular dystrophy (DMD) is an X-linked genetic disease primarily affecting boys causing loss of the dystrophin protein, ultimately leading to muscle wastage... (Review)
Review
Duchenne muscular dystrophy (DMD) is an X-linked genetic disease primarily affecting boys causing loss of the dystrophin protein, ultimately leading to muscle wastage and death by cardiac or respiratory failure. The genetic mutation involved can be overcome with antisense oligonucleotides which bind to a pre-mRNA and results in reading frame restoration by exon skipping. Phosphorodiamidate morpholino oligonucleotides (PMOs) are a class of antisense agents with a neutral backbone derived from RNA which can induce effective exon skipping. In this review, the evolution of PMOs in exon skipping therapy for the last two decades has been detailed with the gradual structural and functional advancements. Even though the success rate of PMObased therapy has been high with four FDA approved drugs, several key challenges are yet to overcome, one being the dystrophin restoration in cardiac muscle. The current scenario in further improvement of PMOs has been discussed along with the future perspectives that have the potential to revolutionize the therapeutic benefits in DMD.
Topics: Male; Humans; Morpholinos; Dystrophin; Muscular Dystrophy, Duchenne; Oligonucleotides, Antisense; Exons
PubMed: 37846020
DOI: No ID Found -
Journal of Genetics and Genomics = Yi... Jul 2019Gene knockdown approaches using antisense oligo nucleotides or analogs such as siRNAs and morpholinos have been widely adopted to study gene functions although the... (Review)
Review
Gene knockdown approaches using antisense oligo nucleotides or analogs such as siRNAs and morpholinos have been widely adopted to study gene functions although the off-target issue has been always a concern in these studies. On the other hand, classic genetic analysis relies on the availability of loss-of-function or gain-of-function mutants. The fast development of genome editing technologies such as TALEN and CRISPR/Cas9 has greatly facilitated the generation of null mutants for the functional studies of target genes in a variety of organisms such as zebrafish. Surprisingly, an unexpected discrepancy was observed between morphant phenotype and mutant phenotype for many genes in zebrafish, i.e., while the morphant often displays an obvious phenotype, the corresponding null mutant appears relatively normal or only exhibits a mild phenotype due to gene compensation. Two recent reports have partially answered this intriguing question by showing that a pre-mature termination codon and homologous sequence are required to elicit the gene compensation and the histone modifying complex COMPASS is involved in activating the expression of the compensatory genes. Here, I summarize these exciting new progress and try to redefine the concept of genetic compensation and gene compensation.
Topics: Animals; Dosage Compensation, Genetic; Gene Expression Regulation; Gene Knockdown Techniques; Genotype; Models, Genetic; Morpholinos; Multigene Family; Mutation; Nonsense Mediated mRNA Decay; Phenotype; RNA, Messenger; Zebrafish
PubMed: 31377237
DOI: 10.1016/j.jgg.2019.07.001