Immunophenotype of a mouse model of LAMA2-deficient congenital muscular



Poster Number: 192


Yonne K Tenorio de Menezes, PhD, University of Pittsburgh, Jia Qi Cheng Zhang, University of Pittsburgh, Marie Johnson, B.S., University of Pittsburgh, Dwi U. Kemaladewi, PhD, University of Pittsburgh

LAMA2-deficient congenital muscular dystrophy (LAMA2-CMD) is an autosomal recessive disorder caused by mutations in the LAMA2 gene, which encodes the LAMA2 protein crucial for myogenesis and maintenance of healthy muscle. The immune cells are important in regulating all facets of muscle homeostasis and disease. However, a comprehensive profile of the immune cell composition in LAMA2-CMD muscle remains understudied. Furthermore, we observed evidence of immune infiltration in the lungs of the LAMA2-CMD mouse model, indicating yet another facet of disease pathophysiology to be explored. Importantly, such knowledge would be essential in the design and development of future therapeutic interventions for LAMA2-CMD. In this study, we aim to fill in the knowledge gap by interrogating the spatiotemporal dynamic of lymphocytes and myeloid cells in a LAMA2-CMD mouse model (dyW/dyW). We performed a time-course flow cytometry analysis in peripheral blood, muscles, and lungs isolated from the dyW/dyW and wildtype littermates at the age of 2-4 weeks. We found that the dyW/dyW mice displayed an increased frequency of neutrophils and monocytes in the blood. We observed a significant increase in the total cell counts and frequency of leukocytes in the muscles of dyW/dyW mice compared to wildtype controls. By 2 weeks of age, the major infiltrating cell types in LAMA2-deficient muscles were CD4+ T cells, NK cells, macrophages, and neutrophils, suggesting that these cell types might be involved in early muscle pathology in LAMA2-CMD. In the lungs, there were no differences observed in the total cell counts and frequency of CD45+ cells, as well as CD3+ , CD4+ , and CD8+ T cells between the groups. However, we observed a reduced number of NK cells over time, in particular at the age of 3 and 4 weeks of age. In contrast, neutrophils and macrophages (M1) were significantly higher in dyW/dyW mice at 2 and 4 weeks of age, suggesting that these populations may play a role in the injury observed in the lungs of dyW/dyW mice. Overall, our finding shows that the dyW/dyW mice display altered frequencies of cells involved in inflammatory process such as CD4+ T cells, neutrophils, monocytes, macrophages, and NK cells, which vary depending on the tissue and disease onset. Our study provides the necessary foundation to further explore the efficacy and safety of a variety of innovative therapeutic interventions for LAMA-CMD, including but not limited to gene therapy.