Abstract
Laminin-α2–related congenital muscular dystrophy (LAMA2-CMD) is a severe neuromuscular disorder caused by mutations in the LAMA2 gene, leading to loss of heterotrimers laminin-211/221, key components of the skeletal muscle extracellular matrix. Their absence disrupts adhesion between the cytoskeleton and extracellular matrix, resulting in progressive muscle wasting. Laminin-211/221 interacts with adhesion complexes such as the dystrophin/utrophin glycoprotein complex and α7β1-integrin. However, the regulatory mechanisms of these laminin-binding complexes and the broader role of laminin’s influence on the formation of the macromolecular network in skeletal muscle remain unclear. We previously demonstrated that delivering mouse laminin-111 to the dyW–/– mouse model of LAMA2-CMD prevented disease progression, improved strength, and extended survival. We hypothesize that laminin-111, the embryonic laminin isoform, restores key adhesion-signaling networks. Using spatial proteomics on patient and mouse muscle, we identified loss of essential signaling components: heat shock proteins 27 and 70, c-Jun N-terminal kinase, and glucose transporter 1 in laminin-α2–deficient muscle. Treatment with recombinant human laminin-111 (rhLAM-111) restored protein localization, reduced ROS, and promoted glycolytic, prosurvival signaling. These findings highlight laminin’s role in maintaining muscle homeostasis and metabolism and support the therapeutic potential of rhLAM-111 for treating LAMA2-CMD by restoring adhesion and intracellular signaling in dystrophic muscle.
Authors
Hailey J. Hermann, Ryan D. Wuebbles, Marisela Dagda, Axel Muñoz, Lauren L. Parker, Paula C. Guzman, Lola T. Byrne, Steven A. Moore, Dean J. Burkin
Figure 8
RhLAM-111 treatment increases cytosolic heat shock protein expression and enhances GLUT1 localization to the sarcolemma after 7 days of treatment.
