Proteolysis of fibrillin-2 microfibrils is essential for normal skeletal development.
Proteolysis of fibrillin-2 microfibrils is essential for normal skeletal development.
复制标题
纤维蛋白-2微原纤维的蛋白水解对骨骼的正常发育至关重要。
DOI：
10.7554/elife.71142
复制
发表时间：
2022-05-03
期刊：
影响因子：
7.7
通讯作者：
Schipani, Ernestina
中科院分区：
文献类型：
--
作者：
Mead, Timothy J.;Martin, Daniel R.;Wang, Lauren W.;Cain, Stuart A.;Gulec, Cagri;Cahill, Elisabeth;Mauch, Joseph;Reinhardt, Dieter;Lo, Cecilia;Baldock, Clair;Apte, Suneel S.;Schipani, Ernestina
胚胎细胞外基质（ECM）在发育过程中会过渡到成熟的ECM，但在这一时期确保ECM蛋白稳定的机制尚不清楚。纤维蛋白微原纤维是具有结构和调节作用的大分子ECM复合物。在小鼠中，编码主要微纤维成分的Fbn1和Fbn2在胚胎发生期间强烈表达，但在成年组织微纤维中观察到的主要成分是纤原蛋白1。本研究通过分析Adamts6和Adamts10突变小鼠胚胎，分别和联合缺乏这些同源的分泌金属蛋白酶，以及微纤维的体外分析、Adamts6 -原纤维蛋白亲和力的测量和Adamts6 -切割位点的n端组学发现，确定了一种促进出生后纤维蛋白2减少和纤维蛋白1优势的蛋白抑制机制。单独缺乏ADAMTS6或与ADAMTS10联合缺乏ADAMTS10会导致软骨膜中纤维蛋白-2过量，骨骼发育受损，表现为聚集蛋白和软骨连接蛋白的急剧减少，软骨中BMP信号受损，富含纤维蛋白-2的组织中GDF5的吸收增加。虽然ADAMTS6可切割为微纤维组装提供初始支架的纤连蛋白1、纤连蛋白2和纤连蛋白，但通过基因减少Fbn2而非Fbn1逆转ADAMTS6 -/-胚胎中的缺陷，明确确立了ADAMTS6与纤连蛋白2之间蛋白酶底物关系的首要地位。
The embryonic extracellular matrix (ECM) undergoes transition to mature ECM as development progresses, yet few mechanisms ensuring ECM proteostasis during this period are known. Fibrillin microfibrils are macromolecular ECM complexes serving structural and regulatory roles. In mice, Fbn1 and Fbn2, encoding the major microfibrillar components, are strongly expressed during embryogenesis, but fibrillin-1 is the major component observed in adult tissue microfibrils. Here, analysis of Adamts6 and Adamts10 mutant mouse embryos, lacking these homologous secreted metalloproteases individually and in combination, along with in vitro analysis of microfibrils, measurement of ADAMTS6-fibrillin affinities and N-terminomics discovery of ADAMTS6-cleaved sites, identifies a proteostatic mechanism contributing to postnatal fibrillin-2 reduction and fibrillin-1 dominance. The lack of ADAMTS6, alone and in combination with ADAMTS10 led to excess fibrillin-2 in perichondrium, with impaired skeletal development defined by a drastic reduction of aggrecan and cartilage link protein, impaired BMP signaling in cartilage, and increased GDF5 sequestration in fibrillin-2-rich tissue. Although ADAMTS6 cleaves fibrillin-1 and fibrillin-2 as well as fibronectin, which provides the initial scaffold for microfibril assembly, primacy of the protease-substrate relationship between ADAMTS6 and fibrillin-2 was unequivocally established by reversal of the defects in Adamts6-/- embryos by genetic reduction of Fbn2, but not Fbn1.