A Study Of The Role Of Metalloproteinase ADAMTS18 In Aortic Arch And Common Carotid Artery Development

Background:The ADAMTS(A disintegrin and metalloproteinase with thrombospondin motifs)protein superfamily includes 19 secreted metalloproteinases.They have diverse roles in various vascular diseases by the non-enzymatic or cleavage of extracellular matrix(ECM).The members of ADAMTS are involved in the development and morphogenesis of various organs,but their research in the field of early embryonic vascular development is rarely reported.As an"orphan ADAMTS",the biological function of ADAMTS18 has not been fully revealed and yet.Our team has successfully constructed an Adamts18 knockout(Adamts18^-/-)tool mouse in the previous research,and we have found that all of Adamts18^-/-mouse showed common carotid artery abnormality which suggest that ADAMTS18 may play an important role in embryonic vascular development.In this paper,we will study deeply with ADAMTS18 function in embryonic vascular development.Methods and results:1.In situ hybridization,immunohistochemistry,and cellular immunofluorescence in Adamts18^+/+mice showed that Adamts18 m RNA was expressed in the vicinity of the dorsal arch artery from E10.5.The expression increased and concentrated in the fibroblasts and mesenchymal cells around the vascular remodeling,the airway,and the thymus primordium followed by development and remodeling of the branchial arch artery.Finally,the expression decreased with the end of the embryonic period until there was no obvious expression near the carotid thoracic artery after birth.2.By observing in situ with Adamts18^+/+and Adamts18^-/-mice,ADAMTS18 deficiency was found to cause abnormal development of the aortic arch(AOAR)and the common carotid artery(CCA),results in increased interval between innominate artery and L-CCA and reduced length of CCA from ascending AOAR starting point to ICA-ECA branching point and leads to the deletion of carotid body,hypoplastic thymus.Ink injection in embryo shows that the aortic deformity appears from E13.5.The above phenotype appeared in 100%of the observed Adamts18^-/-mice.The results of vascular casting showed that the branches of the middle cerebral artery(MCA)of Adamts18^-/-mice were mutated in different brain regions,This leads to significant differences in cerebral infarction areas during stroke.3.The results of Immunohistochemistry and fluorescencea,Special staining,q RT-PCR,Western blotting showed that the ECM which located in CCA and perivascular space were disordered:collagen,fibronectin,aggrecan showed ectopic deposition,elastic fibers increased in vascular wall,fibrillin-1 was up-regulated,and laminin was down-regulated.Immunofluorescence staining showed that the vascular smooth muscle cells of the common carotid artery increased,and the Notch3 signaling pathway was significantly activated.Conclusion:ADAMTS18 is secreted in perivascular fibroblasts and mesenchymal cells during the remodeling and extension of the aortic arch and carotid artery,and affects Notch3 signaling by regulating the abundance and distribution of fibronectin and fibrillin-1.The pathway in turn affects the fate of the differentiation of cardiac neural crest cells into vascular smooth muscle cells,and ultimately leads to abnormal development of the common carotid artery,aortic arch and its appendages.Significance:This study has discovered and confirmed for the first time that ADAMTS18 protein can regulate early vascular remodeling by affecting the extracellular matrix.It not only expands the new functions and mechanisms of ADAMTS family members in early vascular development,but also provides a new perspective and new molecular targets for the clinical diagnosis and treatment of common carotid artery related vascular diseases.