Targeting Galectin-3 to modulate inflammation in LAMA2-deficient congenital muscular dystrophy
LAMA2-deficient congenital muscular dystrophy (LAMA2-CMD) is a severe neuromuscular disorder caused by LAMA2 mutations, leading to muscle degeneration, chronic inflammation, and fibrosis. Histopathological assessment of muscle biopsies from LAMA2-CMD patients and mouse models show clear evidence of inflammation, which oftentimes are regarded as one of the typical dystrophic hallmarks. However, the composition of immune cells in the laminin-deficient muscles remain understood. Consequently, targeted pharmacological intervention to reduce inflammation has never been tested. In this study, we characterized the immune landscape in dyW mouse model of LAMA2-CMD using RNA sequencing and flow cytometry. Transcriptomic analysis of dyW quadriceps identified 2,143 differentially expressed genes, with most of the upregulated genes belong to immune-related pathways. Lgals3 (Galectin-3) was significantly upregulated (log2FC = 4.27, FDR p-value= 9.21x10-88) and identified as a key upstream regulator of the immune-related pathways. In parallel, flow cytometry analysis revealed elevated leukocyte (CD45?) infiltration, with macrophages as the predominant cell population. Pro-inflammatory (M1) macrophages were increased, whereas anti-inflammatory (M2) macrophages remained low, indicating persistent inflammation and impaired resolution. Interestingly, Galectin-3+ macrophages were significantly enriched, which strongly suggest that Galectin-3 drives inflammation in LAMA2-CMD. Treatment of dyW mice with TD-139, a Galectin-3 inhibitor, reduced leukocyte infiltration, decreased Galectin-3+ macrophages, and shifted macrophage polarization toward an M2 anti-inflammatory profile. In addition, RNA sequencing of TD-139-treated dyW muscles showed upregulation of muscle repair pathways and downregulation of fibrosis-related genes. These findings establish Galectin-3-expressing macrophages as an important player in LAMA2-CMD pathophysiology. Importantly, it warrants further investigation on the therapeutic potential of TD-139-mediated inhibition of Galectin-3, including long-term preclinical study, in LAMA2-CMD and potentially other dystrophic conditions driven by chronic immune activation. Overall design: Transcriptome profile by RNA-seq from isolated quadriceps in 5 weeks old dyW (mouse model of LAMA2-CMD) was compared to healthy wildtype control mice