Project description: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.
Project description:Lymphangioleiomyomatosis (LAM) is a rare disease involving cystic lung destruction by invasive LAM cells. These cells harbor loss-of-function mutations in TSC2, conferring hyperactive mTORC1 signaling. Here, tissue engineering tools are employed to model LAM and identify new therapeutic candidates. Biomimetic hydrogel culture of LAM cells is found to recapitulate the molecular and phenotypic characteristics of human disease more faithfully than culture on plastic. A 3D drug screen is conducted, identifying histone deacetylase (HDAC) inhibitors as anti-invasive agents that are also selectively cytotoxic toward TSC2−/− cells. The anti-invasive effects of HDAC inhibitors are independent of genotype, while selective cell death is mTORC1-dependent and mediated by apoptosis. Genotype-selective cytotoxicity is seen exclusively in hydrogel culture due to potentiated differential mTORC1 signaling, a feature that is abrogated in cell culture on plastic. Importantly, HDAC inhibitors block invasion and selectively eradicate LAM cells in vivo in zebrafish xenografts. These findings demonstrate that tissue-engineered disease modeling exposes a physiologically relevant therapeutic vulnerability that would be otherwise missed by conventional culture on plastic. This work substantiates HDAC inhibitors as possible therapeutic candidates for the treatment of patients with LAM and requires further study.
Project description:Pompe disease is caused by autosomal recessive mutations in the GAA gene, which encodes acid alpha-glucosidase. Although enzyme replacement therapy has recently improved patient survival greatly, the results in skeletal muscles and for advanced disease are still not satisfactory. Here, we report the derivation of Pompe disease induced pluripotent stem cells (PomD-iPSCs) and their potential for pathogenesis modeling, drug testing and disease marker identification. PomD-iPSCs maintained pluripotent features, and had low GAA activity and high glycogen content. Cardiomyocyte-like cells (CMLCs) differentiated from PomD-iPSCs recapitulated the hallmark Pompe disease pathophysiological phenotypes, including high levels of glycogen, abundant intracellular LAMP-1- or LC3-positive granules, and multiple ultrastructural aberrances. Drug rescue assessment showed that exposure of PomD-iPSC-derived CMLCs to rhGAA reversed the major pathologic phenotypes. Further, L-carnitine and 3- methyladenine treatment reduced defective cellular respiration and buildup of phagolysosomes, respectively, in the diseased cells. By comparative transcriptome analysis, we identified glycogen metabolism, lysosome and mitochondria related marker genes whose expression robustly correlated with the therapeutic effect of drug treatment in PomD-iPSC-derived CMLCs. Collectively, these results demonstrate that PomD-iPSCs are a promising in vitro disease model for development of novel therapeutic strategies for Pompe disease. Total RNA were isolated from HESC, HF(Pompe disease), PomD-iPSC, HES-CMLC, and PomD-iPS-CMLC. The series included two HESC lines, two HF(Pompe disease) cell lines, four PomD-iPS cell lines, and HES-CMLC were differentiated from one HESC line(HESC2), PomD-iPS-CMLC were differentiated from 3 PomD-iPS cell lines(PomD-iPSC A10, PomD-iPSC A17, PomD-iPSC B03). Each condition was repeated twice and used HESC as control.