Cooperation of two ADAMTS metalloproteases in closure of the mouse palate identifies a requirement for versican proteolysis in regulating palatal mesenchyme proliferation.
We have identified a role for two evolutionarily related, secreted metalloproteases of the ADAMTS family, ADAMTS20 and ADAMTS9, in palatogenesis. Adamts20 mutations cause the mouse white-spotting mutant belted (bt), whereas Adamts9 is essential for survival beyond 7.5 days gestation (E7.5). Functional overlap of Adamts9 with Adamts20 was identified using Adamts9(+/-);bt/bt mice, which have a fully penetrant cleft palate. Palate closure was delayed, although eventually completed, in both Adamts9(+/-);bt/+ and bt/bt mice, demonstrating cooperation of these genes. Adamts20 is expressed in palatal mesenchyme, whereas Adamts9 is expressed exclusively in palate microvascular endothelium. Palatal shelves isolated from Adamts9(+/-);bt/bt mice fused in culture, suggesting an intact epithelial TGFβ3 signaling pathway. Cleft palate resulted from a temporally specific delay in palatal shelf elevation and growth towards the midline. Mesenchyme of Adamts9(+/-);bt/bt palatal shelves had reduced cell proliferation, a lower cell density and decreased processing of versican (VCAN), an extracellular matrix (ECM) proteoglycan and ADAMTS9/20 substrate, from E13.5 to E14.5. Vcan haploinsufficiency led to greater penetrance of cleft palate in bt mice, with a similar defect in palatal shelf extension as Adamts9(+/-);bt/bt mice. Cell density was normal in bt/bt;Vcan(hdf)(/+) mice, consistent with reduced total intact versican in ECM, but impaired proliferation persisted in palate mesenchyme, suggesting that ADAMTS-cleaved versican is required for cell proliferation. These findings support a model in which cooperative versican proteolysis by ADAMTS9 in vascular endothelium and by ADAMTS20 in palate mesenchyme drives palatal shelf sculpting and extension.
Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland OH 44195, USA.
Hiroyuki
H
Enomoto
Courtney M
CM
Nelson
Robert P T
RP
Somerville
Katrina
K
Mielke
Laura J
LJ
Dixon
Kimerly
K
Powell
Suneel S
SS
Apte
D051722:ADAM Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D000071096:ADAMTS Proteins; D000071119:ADAMTS9 Protein; D000818:Animals; D000831:Animals, Newborn; D002452:Cell Count; D019070:Cell Lineage / Q000235:genetics; D049109:Cell Proliferation; D002972:Cleft Palate / Q000201:enzymology / Q000473:pathology; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D008648:Mesoderm / Q000201:enzymology / Q000473:pathology* / Q000648:ultrastructure; D051379:Mice; D008810:Mice, Inbred C57BL; D009154:Mutation / Q000235:genetics; D038081:Organogenesis / Q000235:genetics; D010159:Palate / Q000201:enzymology* / Q000473:pathology* / Q000648:ultrastructure; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D053675:Versicans / Q000378:metabolism*
D012333:RNA, Messenger; D053675:Versicans; D051722:ADAM Proteins; D000071096:ADAMTS Proteins; D000071119:ADAMTS9 Protein; C479569:Adamts20 protein, mouse; C545434:Adamts9 protein, mouse