Comparison of Lectins as Staining Biomarkers for GNE Myopathy Gene Therapy

Abstract

GNE myopathy (GNEM) is an autosomal recessive disease in which mutations in the GNEgene lead to skeletal muscle weakness and progressive wasting. GNE encodes an essential enzyme of the sialic acid (SA) biosynthetic pathway; thus, decreased SA levels in muscle is a hallmark of GNEM. While several therapeutic approaches to increase SA levels in GNEM patients are under development, these efforts have been hindered by the lack of robust biomarkers to assess SA incorporation into affected muscle tissue at the cellular and molecular level. We sought to address this unmet need by comparing the capacity of glycan‐binding proteins known as lectins to effectively monitor SA levels via fluorescent staining. Here, we compare the efficacy of a panel of SA‐detecting lectins by staining samples from multiple models of GNEM. These models include skeletal muscle of the GNED207VTgGne‐/‐ mouse model of GNEM and cell‐based in vitro models, such as those in which SA is removed by enzymatic activity or its production is precluded by GNE mutation. Together, these results indicate the relative ability of each lectin to detect SA alterations in models of GNEM, revealing specific lectins that can act as predictive biomarkers for this disease that may facilitate the development of novel therapeutic approaches.