Publications by authors named "Larochelle N"

Article Synopsis
  • Protein misfolding and mislocalization are key issues in both familial and sporadic ALS, making the maintenance of protein balance through heat shock proteins (HSPs) an important treatment strategy, but neurons have a high threshold for this response.
  • In experiments with mouse models of ALS, the drugs arimoclomol and RGFP963 showed mixed results: they didn't increase HSP expression in FUS mice but helped improve cognitive function and dendritic spine density.
  • In SOD1 mice, some HSPs were upregulated in muscle but not in spinal cord, with drug treatments enhancing muscle performance without promoting HSP expression, suggesting alternate
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  • * This study analyzed the expression of two specific HSPs, HSPA1A and HSPA8, in cultured motor neurons with ALS-linked variants (TDP-43, FUS, SOD1), finding poor induction of HSPA1A and lowered levels of HSPA8, which hampers protective chaperoning.
  • * Treatments with histone deacetylase inhibitors proved more effective than the HSP coinducer arimoclomol in boosting HSP expression and ensuring neuronal health,
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  • * This study found that histone deacetylase (HDAC) inhibitors can enhance the heat shock response in spinal motor neurons under stress, especially when combined with other HSP-inducing drugs.
  • * Different HDAC inhibitors showed varying effectiveness depending on the type of stress, but they were generally able to improve neuroprotection and reduce the effects of ALS-related mutations.
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Introduction : application of evidence-based practice (EBP) by nurses is uneven and inconsistent. Background : characteristics related to head nurses and organizations influence their interventions to the detriment of EBP. Objectives : this integrative literature review informed by the knowledge-to-action (KTA) framework developed by Straus, Tetroe, and Graham (1) sought to identify the barriers and facilitators encountered by head nurses when implementing EBP among hospital staff nurses.

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Study Objective: In rural settings, long distances and transport times pose a challenge for achieving early reperfusion goals in patients with ST-elevation myocardial infarction (STEMI). This study investigated the association between the method of pre-hospital 12-lead ECG transmission (radio transmission vs. cellular phone transmission) and the success of transmission and legibility of 12-lead ECGs in a rural setting.

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Background: Gutless adenovirus (helper-dependent adenoviral vector; HDAd) and lentiviral vectors (LV) are attractive vectors for the gene therapy of muscle diseases. Because the organization of their DNA (episomal versus integrated) differs, we investigated whether the strength and specificity of ΔUSEx3, a novel muscle-specific promoter previously tested with plasmid, were maintained in the context of these vectors.

Methods: Two HDAds expressing β-galactosidase regulated by ΔUSEx3 or CAG [cytomegalovirus (CMV) enhancer/β-actin promoter], and three LV expressing green fluorescent protein regulated by ΔUSEx3, CMV or a modified skeletal α-actin promoter (SPcΔ5-12), were constructed.

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The protein tyrosine phosphatase (PTPase) Src-homology 2-domain-containing phosphatase (SHP)-1 was recently reported to be a novel regulator of insulin's metabolic action. In order to examine the role of this PTPase in skeletal muscle, we used adenovirus (AdV)-mediated gene transfer to express an interfering mutant of SHP-1 [dominant negative (DN)SHP-1; mutation C453S] in L6 myocytes. Expression of DNSHP-1 increased insulin-induced Akt serine-threonine kinase phosphorylation and augmented glucose uptake and glycogen synthesis.

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Adenoviral vectors (AdV) are popular tools to deliver foreign genes into a wide range of cells. They have also been used in clinical gene therapy trials. Studies on AdV-mediated gene transfer to mammalian oocytes and transmission through the germ line have been reported controversially.

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Article Synopsis
  • The study investigates the role of the coxsackie and adenovirus receptor (CAR) in enhancing adenovirus-mediated gene transfer in mature and dystrophic muscle.
  • Transgenic mice with muscle-specific expression of CAR and a two-step protocol using AAV2 to boost CAR levels showed significant improvements in gene transfer efficiency, particularly in dystrophin-deficient mice.
  • The application of histone deacetylase inhibitors like valproate also elevated CAR levels and enhanced the effectiveness of adenovirus gene delivery in muscle tissues.
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Duchenne muscular dystrophy (DMD) is an X-linked, lethal genetic disorder affecting the skeletal muscle compartment, and is caused by mutation(s) in the dystrophin gene. Gene delivery of microdystrophin constructs using adeno-associated virus (AAV) and antisense-mediated exon skipping restoring the genetic reading frame are two of the most promising therapeutic strategies for DMD. Both approaches use microdystrophin proteins either directly as a desired construct for gene delivery, using the capacity-limited AAV vectors, or as the therapeutic outcome of gene splicing.

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Adenoviral vectors that use the coxsackievirus and adenovirus receptor do not transduce mature muscle efficiently. Group B adenoviruses use CD46 as their cell attachment receptor. To evaluate the utility of vectors based on group B adenoviruses for gene transfer to human skeletal muscle, we assessed the expression of CD46 in biopsied normal skeletal muscle samples and in muscles from patients with Duchenne muscular dystrophy.

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Helper-dependent adenovirus vector (AdV)-mediated full-length dystrophin expression leads to significant mitigation of the dystrophic phenotype of the mdx mouse. However, dystrophin, as a neoantigen, elicits antibody formation. As an alternative approach, we evaluated gene transfer of full-length murine utrophin, a functional homologue of dystrophin that is normally present only at the neuromuscular junction.

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The Coxsackie and adenovirus receptor (CAR), a cell adhesion molecule of the immunoglobulin superfamily, is usually confined to the sarcolemma at the neuromuscular junction in mature skeletal muscle fibers. Previously, we reported that adenovirus-mediated gene transfer is greatly facilitated in hemizygous transgenic mice with extrasynaptic CAR expression driven by a muscle-specific promoter. However, in the present study, when these mice were bred to homozygosity, they developed a severe myopathic phenotype and died prematurely.

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Expression of the coxsackie and adenovirus receptor (CAR) is downregulated in malignant glioma cell lines and is barely detectable in high-grade primary astrocytoma (glioblastoma multiforme). We determined the effect of forced CAR expression on the invasion and growth of the human glioma cell line U87-MG, which does not express any CAR. Although retrovirally mediated expression of full-length CAR in U87-MG cells did not affect monolayer growth in vitro, it did reduce glioma cell invasion in a 3-dimensional spheroid model.

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Intramuscular injection of plasmid is a potential alternative to viral vectors for the transfer of therapeutic genes into skeletal muscle fibers. The low efficiency of plasmid-based gene transfer can be enhanced by electroporation (EP) coupled with the intramuscular application of hyaluronidase. We have investigated several factors that can influence the efficiency of plasmid-based gene transfer.

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Successful gene therapy of Duchenne muscular dystrophy may require the lifelong expression of a therapeutic gene in all affected muscles. The most promising gene delivery vehicles, viral vectors, suffer from several limitations, including immunogenicity, loss of therapeutic gene expression, and a limited packaging capacity. Therefore, various efforts were previously undertaken to use small therapeutic genes and to place them under the control of a strong and muscle-specific promoter.

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Currently, adenoviral transfer of therapeutic genes such as dystrophin is hampered by low transduction efficiency of adult skeletal muscle. This is largely due to the lack of appropriate virus attachment receptors on the myofiber surface. Recent studies in transgenic mice revealed that upregulation of Coxsackie- and adenovirus receptor improves gene transfer efficiency by approximately ten-fold.

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First-generation adenovirus vectors (AdV) have been used successfully to transfer a human dystrophin minigene to skeletal muscle of mdx mice. In most studies, strong viral promoters such as the cytomegalovirus promoter/enhancer (CMV) were used to drive dystrophin expression. More recently, a short version of the muscle creatine kinase promoter (MCK1350) has been shown to provide muscle-specific reporter gene expression after AdV-mediated gene delivery.

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Significant levels of adenovirus (Ad)-mediated gene transfer occur only in immature muscle or in regenerating muscle, indicating that a developmentally regulated event plays a major role in limiting transgene expression in mature skeletal muscle. We have previously shown that in developing mouse muscle, expression of the primary Ad receptor CAR is severely downregulated during muscle maturation. To evaluate how global expression of CAR throughout muscle affects Ad vector (AdV)-mediated gene transfer into mature skeletal muscle, we produced transgenic mice that express the CAR cDNA under the control of the muscle-specific creatine kinase promoter.

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Recombinant adenovirus (AVR) promises to be an efficient vector in gene therapy for neuromuscular diseases, but in preclinical experiments the expression of therapeutic genes is shorter lived in immunocompetent animals than in immunocompromised hosts. Interferons (IFN), which are known to have a role both in early antiviral activity and in late cytotoxic immunoreaction against the virus or transduced cells, may influence the efficiency of gene transfer. In this study we investigated the role of IFNs in determining the efficiency of gene transfer by AVR.

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Replication-defective (E1-E3-deleted) human adenovirus vectors are a promising means of therapeutic gene delivery to skeletal muscle cells. Since the tropism of adenovirus is nonselective, muscle-specific expression of systemically administered vectors can only be achieved by the use of a tissue-specific promoter/enhancer that is small enough to fit the insert capacity of the vector. We have generated two replication-defective adenovirus recombinants (AV) in which the reporter gene (either firefly luciferase or E.

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Adenovirus (AV)-mediated gene transfer into skeletal muscles of adult immune-competent animals has been limited by the fact that a cell-mediated immune attack of the host against transduced muscle fibers prevented efficient long-term transgene expression. More recently, various immunomodulating strategies have been shown to improve the longevity of transgene expression after AV-mediated gene transfer. In this study we treated adult dystrophic (mdx) mice with daily subcutaneous injections of the immunosuppressive drug FK506 (tacrolimus) over 5, 10, 30 and 60 days after AV-mediated dystrophin gene transfer and compared the transduction level with saline-injected mdx controls.

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