GSE106201
Distinct effects of genetic and pharmacological inhibition of galectin-3 on cardiac fibrosis and function in a mouse model of dilated cardiomyopathy
Background: Galectin-3 is upregulated in heart disease, and its inhibition has been reported to confer benefits on cardiac remodeling and dysfunction. It remains unknown whether galectin-3 plays a biological role in a setting of dilated cardiomyopathy (DCM). We determined galectin-3 expression in transgenic (TG) mice with cardiac-restricted overexpression of mammalian sterile 20-like kinase 1 (Mst1-TG), and studied the effects of pharmacological and genetic inhibition of galectin-3 on the DCM phenotype. Methods and results: The DCM phenotype of male Mst1-TG mice was assessed at 2, 3 and 6 months of age. Galectin-3 deletion in Mst1-TG mice was achieved by cross-breeding Mst1-TG with galectin-3 knockout (KO) mice to produce genotypes of non-TG (nTG), KO, Mst1-TG, and Mst1-TG mice with partial or complete deletion of the galectin-3 gene. Pharmacological inhibition of galectin-3 was tested by treating Mst1-TG mice with modified citrus pectin for 4 months. Changes in the DCM phenotype were assessed by serial echocardiography, ECG recording and biochemical assays. Mst1-TG mice exhibited upregulated levels of cardiac galectin-3 expression by 40~50-fold, atrial dilatation, reduced left ventricular (LV) ejection fraction, increased LV volume at systole and diastole, atrial conduction delay, severe cardiac fibrosis, and upregulated fibrosis-related genes. Galectin-3 gene deletion in Mst1-TG mice attenuates increased LV volume at systole and diastole, atrial conduction delay and cardiac fibrogenesis. Treatment with modified citrus pectin in Mst1-TG mice did not confer benefit on the DCM phenotype, possibly due to the very high expression of galectin-3. Conclusion: Galectin-3 expression is markedly increased in Mst1-TG hearts exhibiting DCM. Galectin-3 gene deletion effectively suppressed cardiac fibrotic signaling and LV dilatation, and was associated with better function. Thus, suppression of galectin-3 expression may represent a potential therapeutic approach in DCM. The development of new galectin-3 inhibitors are warranted. Overall design: We performed RNA-seq on left ventricle samples from control and Gal-3 knock-out mice in two genetic backgrounds: wild type C57BL6 and the Mst-1 overexpressing mouse that is frequently used as a model for dilated cardiomyopathy. Between 5 and 8 replicates from each group were processed.