MEMO1 Is Required for Ameloblast Maturation and Functional Enamel Formation

Coordinated mineralization of soft tissue is central to organismal form and function, while dysregulated mineralization underlies several human pathologies. Oral epithelial-derived ameloblasts are polarized, secretory cells responsible for generating enamel, the most mineralized substance in the human body. Defects in ameloblast development result in enamel anomalies, including amelogenesis imperfecta. Identifying proteins critical in ameloblast development can provide insight into specific pathologies associated with enamel-related disorders or, more broadly, mechanisms of mineralization. Previous studies identified a role for MEMO1 in bone mineralization; however, whether MEMO1 functions in the generation of additional mineralized structures remains unknown. Here, we identify a critical role for MEMO1 in enamel mineralization. First, we show that Memo1 is expressed in ameloblasts and, second, that its conditional deletion from ameloblasts results in enamel defects, characterized by a decline in mineral density and tooth integrity. Histology revealed that the mineralization defects in Memo1 mutant ameloblasts correlated with a disruption in ameloblast morphology. Finally, molecular profiling of ameloblasts and their progenitors in Memo1 oral epithelial mutants revealed a disruption to cytoskeletal-associated genes and a reduction in late-stage ameloblast markers, relative to controls. Collectively, our findings integrate MEMO1 into an emerging network of molecules important for ameloblast development and provide a system to further interrogate the relationship of cytoskeletal and amelogenesis-related defects.

Automated summary

Coordinated mineralization of soft tissue is vital for organismal form and function, and dysregulated mineralization can lead to various human pathologies. In this study, the role of MEMO1 in enamel mineralization was investigated. It was found that MEMO1 is critical for enamel development, as its deletion in ameloblasts resulted in enamel defects and a disruption in ameloblast morphology. Molecular profiling further revealed that cytoskeletal-associated genes were affected in Memo1 mutants. These findings provide valuable insights into the mechanisms of ameloblast development and can contribute to understanding enamel-related disorders.