ADAM10 is Expressed by Ameloblasts, Cleaves the RELT TNF Receptor Extracellular Domain and Facilitates Enamel Development

Atsushi Ikeda,John D Bartlett,Maiko Suzuki,Benjamin R Blumberg,Shifa Shahid

doi:10.1038/s41598-019-50277-y

Atsushi Ikeda, John D Bartlett + Show 3 more

Open Access

https://doi.org/10.1038/s41598-019-50277-y

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Journal: Scientific Reports	Publication Date: Oct 1, 2019
Citations: 12	License type: open-access

Affiliation: The Ohio State University, Augusta University

Abstract

MMP20 cleaves cadherins and may facilitate cell movement, however MMP20 is not known to cleave tight junction or desmosome proteins. Ameloblasts had not previously been screened for membrane anchored proteases that could contribute to cell movement. Here we performed a PCR screen for proteolyticlly active A Disintegrin And Metalloproteinase (ADAM) family members. These proteinases are termed sheddases because they have a transmembrane domain and their catalytic domain on the cell surface can function to release anchored proteins. Significantly, ADAMs can be targeted to specific substrates on the cell membrane through their interaction with tetraspanins. Six ADAMs (ADAM8, 9, 10, 15, 17, 19) were expressed in mouse enamel organs. We show that Adam10 expression begins in the apical loop, continues through the secretory stage and abruptly ends at the transition stage when ameloblast migration ceases. ADAM10 cleaves cadherins and tight junction plus desmosome proteins and is well characterized for its role in cell movement. ADAM10 facilitated LS8 cell migration/invasion through a Matrigel coated membrane and we demonstrate that ADAM10, but not ADAM17 cleaves the RELT extracellular domain. This striking result is significant because RELT mutations cause amelogenesis imperfecta (AI) and this directly links ADAM10 to an important role in enamel development.

Highlights

A Disintegrin And Metalloproteinases (ADAMs) are a family of metalloproteinases that contain transmembrane domains that function in cell adhesion, migration, angiogenesis and cell signaling[5]
We discovered that Adams 8, 9,10,15,17 and 19 were expressed in the murine enamel organ (Fig. 1)
To determine if these Adams were differentially expressed between the secretory and maturation stages of development, expression was assessed in first molars from 5 day-old pups (P5, predominantly secretory stage) and in molars from P12 pups

Summary

Introduction

A Disintegrin And Metalloproteinases (ADAMs) are a family of metalloproteinases that contain transmembrane domains that function in cell adhesion, migration, angiogenesis and cell signaling[5]. ADAM proteinases have not been identified in the enamel organ (EO) of any species. We sought to determine if ADAMs capable of proteolytic activity are expressed in the mouse enamel organ. We identified six proteolytically active Adams expressed in the enamel organ. Among those six was Adam[10]. ADAM10 cleaves a wide range of cell adhesion molecules, 3. Adam[10] expression is strongly associated with cell migration, 4. ADAM10 expression abruptly ceases as ameloblasts enter the transition stage of enamel development. This is when ameloblasts stop moving relative to one another. We show that recombinant-human ADAM10 (rhADAM10) cleaves the RELT extracellular domain, implicating ADAM10 as an essential component in enamel development

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