Targeting Neural Chloride Homeostasis Mitigates Motor Deficits in Dystrophic Mice

DMD is a severe X-linked disorder caused by dystrophin deficiency and is characterized by progressive muscle degeneration and weakness. Although research has traditionally focused on skeletal muscle pathology, growing evidence indicates that dystrophin deficiency also disrupts the central and peripheral nervous systems. Altered inhibitory signaling, impaired chloride balance, neuronal hyperexcitability, and metabolic dysfunction may all contribute to disease progression.

KCC2 is crucial for maintaining low intracellular chloride concentrations and enabling the inhibitory actions of gamma-aminobutyric acid, but its role in dystrophy-associated neuromuscular dysfunction remains insufficiently understood. Consequently, it is necessary to investigate whether restoring chloride homeostasis can produce coordinated functional, molecular, and metabolic benefits across the neuromuscular system.

A study (DOI: 10.48130/targetome-0026-0041) published in Targetome on 11 August 2026 by Alexandre LR Oliveira's team, University of Campinas (UNICAMP), reports that CLP290 improved locomotion and induced coordinated neural and metabolic adaptations without restoring dystrophin expression.

The researchers studied four-week-old male mdx mice, a widely used model of DMD, alongside non-dystrophic C57BL/10 controls. Animals received CLP290 at doses of 1, 5, or 10 mg·kg⁻¹ through an intradermal polycaprolactone/gelatin methacryloyl biomembrane designed for controlled release over seven consecutive days. Automated CatWalk gait analysis identified 10 mg·kg⁻¹ as the most effective dose. At this dose, treated mdx mice displayed a narrower hind-limb base of support and smaller maximum paw-contact areas, indicating improved balance, gait stability, and plantar-contact dynamics.

Western blotting confirmed that these functional gains occurred without restoration of the missing 427-kDa dystrophin protein. Immunohistochemical analysis of lumbar spinal cord sections showed that CLP290 increased KCC2 expression in motor nuclei and motor-neuron membranes. It also increased glutamate decarboxylase 65, a marker linked to gamma-aminobutyric acid synthesis, while reducing vesicular glutamate transporter 1 and AMPA receptor labeling associated with excitatory signaling. Expression of glial fibrillary acidic protein, which was elevated in untreated mdx mice and indicated astrocytic activation, fell after treatment to levels that no longer differed significantly from non-dystrophic controls.

To examine metabolic responses, the researchers combined nuclear magnetic resonance metabolomics of the lumbar spinal cord and sciatic nerve with untargeted liquid chromatography-mass spectrometry of tibialis anterior muscle. CLP290 produced its strongest metabolic effects in the spinal cord, altering creatine, phosphocreatine, lactate, N-acetylaspartate, myo-inositol, carnitine, and several excitatory or inhibitory amino-acid metabolites.

Sciatic-nerve responses were more limited, although alanine and metabolites related to osmotic regulation showed treatment-dependent changes. Muscle metabolomics revealed clear differences between dystrophic and control animals and showed that CLP290 partially shifted the dystrophic metabolic profile toward that of controls, particularly in pathways involving amino acids, carnitine metabolism, lipid processing, and oxidative stress.

Together, the results support a model in which CLP290 improves motor function primarily by stabilizing spinal motor-neuron chloride homeostasis and promoting coordinated neurometabolic adaptation rather than repairing dystrophin deficiency itself. Because the mdx mouse has a milder phenotype and greater regenerative capacity than human DMD, the magnitude of benefit cannot yet be extrapolated directly to patients. Nevertheless, the study identifies KCC2-related signaling as a promising therapeutic target and supports further investigation of CLP290 as an early adjunctive strategy for delaying functional decline and maintaining mobility in DMD.