AAV-based shRNA silencing of NF-κB ameliorates muscle pathologies in mdx mice

The transcription factor nuclear factor κB (NF-κB)/p65 is the master regulator of inflammation in Duchenne muscular dystrophy (DMD). Disease severity is reduced by NF-κB inhibition in the mdx mouse, a murine DMD model; however, therapeutic targeting of NF-κB remains problematic for patients because of its fundamental role in immunity. In this investigation, we found that the therapeutic effect of NF-κB blockade requires hepatocyte growth factor (HGF) production by myogenic cells. We found that deleting one allele of the NF-κB subunit p65 (p65+/−) improved the survival and enhanced the anti-inflammatory capacity of muscle-derived stem cells (MDSCs) following intramuscular transplantation. Factors secreted from p65+/− MDSCs in cell cultures modulated macrophage cytokine expression in an HGF-receptor-dependent manner. Indeed, we found that following genetic or pharmacologic inhibition of basal NF-κB/p65 activity, HGF gene transcription was induced in MDSCs. We investigated the role of HGF in anti-NF-κB therapy in vivo using mdx;p65+/− mice, and found that accelerated regeneration coincided with HGF upregulation in the skeletal muscle. This anti-NF-κB-mediated dystrophic phenotype was reversed by blocking de novo HGF production by myogenic cells following disease onset. HGF silencing resulted in increased inflammation and extensive necrosis of the diaphragm muscle. Proteolytic processing of matrix-associated HGF is known to activate muscle stem cells at the earliest stages of repair, but our results indicate that the production of a second pool of HGF by myogenic cells, negatively regulated by NF-κB/p65, is crucial for inflammation resolution and the completion of repair in dystrophic skeletal muscle. Our findings warrant further investigation into the potential of HGF mimetics for the treatment of DMD.

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“…Histological analysis was carried out by hematoxylin and eosin staining (H&E), as described previously. 46 …”

Section: Methodsmentioning

confidence: 99%

NF-κB inhibition reveals a novel role for HGF during skeletal muscle repair

et al. 2015

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“…A recent study has also shown that inhibition of NF-κB improves the proliferation, differentiation, and transplantation of muscle-derived stem cells in dystrophic muscle (Lu et al, 2012). Furthermore, shRNA-mediated knockdown of RelA or overexpression of a dominant negative mutant of IKKα or IKKβ using adeno-associated virus (AAV) also ameliorated pathology and improved regeneration in mdx mice (Tang et al, 2010; Yang et al, 2012). Importantly, specific depletion of IKKβ in macrophages also considerably reduced the expression of inflammatory cytokines, muscle pathology, and enhanced myofiber regeneration (Acharyya et al, 2007) further suggesting that macrophages play an important role in DMD pathology possibly through increased production of NF-κB-regulated proinflammatory cytokines in skeletal muscle microenvironment.…”

Section: Nf-κb Signalingmentioning

confidence: 99%

Wasting mechanisms in muscular dystrophy

Shin

Tajrishi

Ogura

et al. 2013

The International Journal of Biochemistry & Cell Biology

116

135

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Muscular dystrophy is a group of more than 30 different clinical genetic disorders that are characterized by progressive skeletal muscle wasting and degeneration. Primary deficiency of specific extracellular matrix, sarcoplasmic, cytoskeletal, or nuclear membrane protein results in several secondary changes such as sarcolemmal instability, calcium influx, fiber necrosis, oxidative stress, inflammatory response, breakdown of extracellular matrix, and eventually fibrosis which leads to loss of ambulance and cardiac and respiratory failure. A number of molecular processes have now been identified which hasten disease progression in human patients and animal models of muscular dystrophy. Accumulating evidence further suggests that aberrant activation of several signaling pathways aggravate pathological cascades in dystrophic muscle. Although replacement of defective gene with wild-type is paramount to cure, management of secondary pathological changes has enormous potential to improving the quality of life and extending lifespan of muscular dystrophy patients. In this article, we have reviewed major cellular and molecular mechanisms leading to muscle wasting in muscular dystrophy.

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“…Duchenne muscular dystrophy (DMD) is the most common of the muscular dystrophies and is caused by mutations in the dystrophin gene . The purpose of this article is to highlight the current knowledge and advancements in the evolving paradigms in clinical pharmacology and therapeutics for this devastating musculoskeletal disease.…”

Section: Paradigm Shiftsmentioning

confidence: 99%

Evolving paradigms in clinical pharmacology and therapeutics for the treatment of Duchenne muscular dystrophy

Huard

Lü

2016

Clin Pharma and Therapeutics

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Progressive muscle weakness and degeneration due to the lack of dystrophin eventually leads to the loss of independent ambulation by the middle of the patient's second decade, and a fatal outcome due to cardiac or respiratory failure by the third decade. More specifically, loss of sarcolemmal dystrophin and the dystrophin-associated glycoprotein (DAG) complex promotes muscle fiber damage during muscle contraction. This process results in an efflux of creatine kinase (CK), an influx of calcium ions, and the recruitment of T cells, macrophages, and mast cells to the damaged muscle, causing progressive myofiber necrosis. For the last 20 years, the major goal in the development of therapeutic approaches to alleviate muscle weakness in DMD has been centered on the restoration of dystrophin or proteins that are analogous to dystrophin, such as utrophin, through a variety of modalities including cell therapy, gene therapy, gene correction, and the highly promising techniques utilizing CRISPR/Cas9 technology. Despite the development of new therapeutic options, there still exist numerous challenges that we must face with regard to these new strategies and, consequently, we still do not have any feasible options available to ultimately slow the progression of this devastating disease. The purpose of this article is to highlight the current knowledge and advancements in the evolving paradigms in clinical pharmacology and therapeutics for this devastating musculoskeletal disease.

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AAV-based shRNA silencing of NF-κB ameliorates muscle pathologies in mdx mice

Cited by 32 publications

References 35 publications

NF-κB inhibition reveals a novel role for HGF during skeletal muscle repair

NF-κB inhibition reveals a novel role for HGF during skeletal muscle repair

Wasting mechanisms in muscular dystrophy

Evolving paradigms in clinical pharmacology and therapeutics for the treatment of Duchenne muscular dystrophy

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