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Neuromuscul Disord. 2014 Jul;24(7):583-95. doi: 10.1016/j.nmd.2014.04.006. Epub 2014 Apr 26.

Long-term administration of the TNF blocking drug Remicade (cV1q) to mdx mice reduces skeletal and cardiac muscle fibrosis, but negatively impacts cardiac function.

Author information

1
Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA; Center for Duchenne Muscular Dystrophy at UCLA, Los Angeles, CA 90095, USA.
2
Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
3
Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA; Paul Wellstone Muscular Dystrophy Center, Philadelphia, PA 19104, USA.
4
Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA; Center for Duchenne Muscular Dystrophy at UCLA, Los Angeles, CA 90095, USA; Paul Wellstone Muscular Dystrophy Center, Philadelphia, PA 19104, USA. Electronic address: mspencer@mednet.ucla.edu.

Abstract

Duchenne muscular dystrophy (DMD) is a degenerative skeletal muscle disease caused by mutations in the gene encoding dystrophin (DYS). Tumor necrosis factor (TNF) has been implicated in the pathogenesis since short-term treatment of mdx mice with TNF blocking drugs proved beneficial; however, it is not clear whether long-term treatment will also improve long-term outcomes of fibrosis and cardiac health. In this investigation, short and long-term dosing studies were carried out using the TNF blocking drug Remicade and a variety of outcome measures were assessed. Here we show no demonstrable benefit to muscle strength or morphology with 10mg/kg or 20mg/kg Remicade; however, 3mg/kg produced positive strength benefits. Remicade treatment correlated with reductions in myostatin mRNA in the heart, and concomitant reductions in cardiac and skeletal fibrosis. Surprisingly, although Remicade treated mdx hearts were less fibrotic, reductions in LV mass and ejection fraction were also observed, and these changes coincided with reductions in AKT phosphorylation on threonine 308. Thus, TNF blockade benefits mdx skeletal muscle strength and fibrosis, but negatively impacts AKT activation, leading to deleterious changes to dystrophic heart function. These studies uncover a previously unknown relationship between TNF blockade and alteration of muscle growth signaling pathways.

KEYWORDS:

AKT; Inflammation; Muscular dystrophy; Myostatin; Signaling; Treatment; mdx mouse

PMID:
24844454
PMCID:
PMC4122520
DOI:
10.1016/j.nmd.2014.04.006
[Indexed for MEDLINE]
Free PMC Article

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