Peptide-Based Inhibition of NF-κB Rescues Diaphragm Muscle Contractile Dysfunction in a Murine Model of Duchenne Muscular Dystrophy

Jennifer M Peterson,Jill A Rafael-Fortney,Michael Freitas,Joe N Kornegay,Jerry R Mendell,Albert S Baldwin,Pat Flood,William Kline,Benjamin D Canan,Daniel J Ricca,Pravin Kaumaya,Kelly Dirienzo,Dawn A Delfín,Paul D Robbins,Brian Kaspar,Denis G Guttridge,Paula R Clemens,Paul M L Janssen

doi:10.2119/molmed.2010.00263

Abstract

Deterioration of diaphragm function is one of the prominent factors that contributes to the susceptibility of serious respiratory infections and development of respiratory failure in patients with Duchenne Muscular Dystrophy (DMD). The NF-κB signaling pathway has been implicated as a contributing factor of dystrophic pathology, making it a potential therapeutic target. Previously, we demonstrated that pharmacological inhibition of NF-κB via a small NEMO Binding Domain (NBD) peptide was beneficial for reducing pathological features of mdx mice. Now, we stringently test the effectiveness and clinical potential of NBD by treating mdx mice with various formulations of NBD and use diaphragm function as our primary outcome criteria. We found that administering DMSO-soluble NBD rescued 78% of the contractile deficit between mdx and wild-type (WT) diaphragm. Interestingly, synthesis of a GLP NBD peptide as an acetate salt permitted its solubility in water, but as a negative consequence, also greatly attenuated functional efficacy. However, replacing the acetic acid counterion of the NBD peptide with trifluoroacetic acid retained the peptide's water solubility and significantly restored mdx diaphragm contractile function and improved histopathological indices of disease in both diaphragm and limb muscle. Together, these results support the feasibility of using a mass-produced, water-soluble NBD peptide for clinical use.

Highlights

IntroductionIs a deadly genetic disease characterized mainly by progressive weakness of the skeletal musculature
Duchenne muscular dystrophy (DMD)is a deadly genetic disease characterized mainly by progressive weakness of the skeletal musculature
We demonstrated that a cell-permeable 11 amino acid peptide that binds to the C-terminal region within IKKα and IKKβ and prevents association with NEMO, called the NEMO Binding Domain (NBD) peptide, blunts the chronic NF-κB signaling in mdx mice [2]

Summary

Introduction

Is a deadly genetic disease characterized mainly by progressive weakness of the skeletal musculature. Loss of ambulation due to skeletal muscle degeneration is the main recognizable phenotypical feature of patients with DMD. More life-threatening complications develop as the disease progresses, with eventual cause of death in most patients as a result of diaphragm and/or cardiac muscle failure [1]. We demonstrated recently that NF-κB inhibition improved contractility of diaphragm muscle in mdx mice, a widely used mouse model of DMD [2]. Those data warranted further investigation into the possibility of thera-

Methods

Results

Conclusion