Explore the vast range of titles available.

Lymphangiogenesis is supported by 2 homologous VEGFR3 ligands, VEGFC and VEGFD. VEGFC is required for lymphatic development, while VEGFD is not. VEGFC and VEGFD are proteolytically cleaved after cell secretion in vitro, and recent studies have implicated the protease a disintegrin and metalloproteinase with thrombospondin motifs 3 (ADAMTS3) and the secreted factor collagen and calcium binding EGF domains 1 (CCBE1) in this process. It is not well understood how ligand proteolysis is controlled at the molecular level or how this process regulates lymphangiogenesis, because these complex molecular interactions have been difficult to follow ex vivo and test in vivo. Here, we have developed and used biochemical and cellular tools to demonstrate that an ADAMTS3-CCBE1 complex can form independently of VEGFR3 and is required to convert VEGFC, but not VEGFD, into an active ligand. Consistent with these ex vivo findings, mouse genetic studies revealed that ADAMTS3 is required for lymphatic development in a manner that is identical to the requirement of VEGFC and CCBE1 for lymphatic development. Moreover, CCBE1 was required for in vivo lymphangiogenesis stimulated by VEGFC but not VEGFD. Together, these studies reveal that lymphangiogenesis is regulated by two distinct proteolytic mechanisms of ligand activation: one in which VEGFC activation by ADAMTS3 and CCBE1 spatially and temporally patterns developing lymphatics, and one in which VEGFD activation by a distinct proteolytic mechanism may be stimulated during inflammatory lymphatic growth.

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 .

Although hundreds of cytosolic or transmembrane molecules form the primary cilium, few secreted molecules are known to contribute to ciliogenesis. Here, homologous secreted metalloproteases ADAMTS9 and ADAMTS20 are identified as ciliogenesis regulators that act intracellularly. Secreted and furin-processed ADAMTS9 bound heparan sulfate and was internalized by LRP1, LRP2 and clathrin-mediated endocytosis to be gathered in Rab11 vesicles with a unique periciliary localization defined by super-resolution microscopy. CRISPR-Cas9 inactivation of ADAMTS9 impaired ciliogenesis in RPE-1 cells, which was restored by catalytically active ADAMTS9 or ADAMTS20 acting in trans , but not by their proteolytically inactive mutants. Their mutagenesis in mice impaired neural and yolk sac ciliogenesis, leading to morphogenetic anomalies resulting from impaired hedgehog signaling, which is transduced by primary cilia. In addition to their cognate extracellular proteolytic activity, ADAMTS9 and ADAMTS20 thus have an additional proteolytic role intracellularly, revealing an unexpected regulatory dimension in ciliogenesis. Ciliogenesis is a complex process requiring hundreds of molecules, although few secreted proteins have been implicated. Here, the authors show that the secreted metalloproteases ADAMTS9 and ADAMTS20 intracellularly regulate ciliogenesis from unique periciliary vesicles with proteolytic activity.

Estrogens and progesterone control breast development and carcinogenesis via their cognate receptors expressed in a subset of luminal cells in the mammary epithelium. How they control the extracellular matrix, important to breast physiology and tumorigenesis, remains unclear. Here we report that both hormones induce the secreted protease Adamts18 in myoepithelial cells by controlling Wnt4 expression with consequent paracrine canonical Wnt signaling activation. Adamts18 is required for stem cell activation, has multiple binding partners in the basement membrane and interacts genetically with the basal membrane-specific proteoglycan, Col18a1 , pointing to the basement membrane as part of the stem cell niche. In vitro, ADAMTS18 cleaves fibronectin; in vivo, Adamts18 deletion causes increased collagen deposition during puberty, which results in impaired Hippo signaling and reduced Fgfr2 expression both of which control stem cell function. Thus, Adamts18 links luminal hormone receptor signaling to basement membrane remodeling and stem cell activation. How hormonal signaling in the mammary epithelium controls the surrounding extracellular matrix is unclear. Here, the authors show that a secreted protease, Adamts18, induced by upstream estrogen-progesterone activated Wnt4 in myoepithelial cells, remodels the basement membrane and contributes to mammary epithelial stemness.

Fibrosis represents the uncontrolled replacement of parenchymal tissue with extracellular matrix (ECM) produced by myofibroblasts. While genetic fate-tracing and single-cell RNA-Seq technologies have helped elucidate fibroblast heterogeneity and ontogeny beyond fibroblast to myofibroblast differentiation, newly identified fibroblast populations remain ill defined, with respect to both the molecular cues driving their differentiation and their subsequent role in fibrosis. Using an unbiased approach, we identified the metalloprotease ADAMTS12 as a fibroblast-specific gene that is strongly upregulated during active fibrogenesis in humans and mice. Functional in vivo KO studies in mice confirmed that Adamts12 was critical during fibrogenesis in both heart and kidney. Mechanistically, using a combination of spatial transcriptomics and expression of catalytically active or inactive ADAMTS12, we demonstrated that the active protease of ADAMTS12 shaped ECM composition and cleaved hemicentin 1 (HMCN1) to enable the activation and migration of a distinct injury-responsive fibroblast subset defined by aberrant high JAK/STAT signaling.

Fibrillin microfibrils are ubiquitous elements of extracellular matrix assemblies that play crucial roles in regulating the bioavailability of growth factors of the transforming growth factor beta superfamily. Recently, several “a disintegrin and metalloproteinase with thrombospondin motifs” (ADAMTS) proteins were shown to regulate fibrillin microfibril function. Among them, ADAMTS17 is the causative gene of Weill-Marchesani syndrome (WMS) and Weill-Marchesani-like syndrome, of which common symptoms are ectopia lentis and short stature. ADAMTS17 has also been linked to height variation in humans; however, the molecular mechanisms whereby ADAMTS17 regulates skeletal growth remain unknown. Here, we generated Adamts17-/- mice to examine the role of Adamts17 in skeletogenesis. Adamts17-/- mice recapitulated WMS, showing shorter long bones, brachydactyly, and thick skin. The hypertrophic zone of the growth plate in Adamts17-/- mice was shortened, with enhanced fibrillin-2 deposition, suggesting increased incorporation of fibrillin-2 into microfibrils. Comprehensive gene expression analysis of growth plates using laser microdissection and RNA sequencing indicated alteration of the bone morphogenetic protein (BMP) signaling pathway after Adamts17 knockout. Consistent with this, phospho-Smad1 levels were downregulated in the hypertrophic zone of the growth plate and in Adamts17-/- primary chondrocytes. Delayed terminal differentiation of Adamts17-/- chondrocytes, observed both in primary chondrocyte and primordial metatarsal cultures, and was prevented by BMP treatment. Our data indicated that Adamts17 is involved in skeletal formation by modulating BMP-Smad1/5/8 pathway, possibly through inhibiting the incorporation of fibrillin-2 into microfibrils. Our findings will contribute to further understanding of disease mechanisms and will facilitate the development of therapeutic interventions for WMS.

Proteolytical processing of the growth factor VEGFC through the concerted activity of CCBE1 and ADAMTS3 is required for lymphatic development to occur. How these factors act together in time and space, and which cell types produce these factors is not understood. Here we assess the function of Adamts3 and the related protease Adamts14 during zebrafish lymphangiogenesis and show both proteins to be able to process Vegfc. Only the simultaneous loss of both protein functions results in lymphatic defects identical to vegfc loss-of-function situations. Cell transplantation experiments demonstrate neuronal structures and/or fibroblasts to constitute cellular sources not only for both proteases but also for Ccbe1 and Vegfc. We further show that this locally restricted Vegfc maturation is needed to trigger normal lymphatic sprouting and directional migration. Our data provide a single-cell resolution model for establishing secretion and processing hubs for Vegfc during developmental lymphangiogenesis. How and where VEGF-C is processed in lymphangiogenesis is unclear. Here, the authors show that development of the zebrafish lymphatic system is locally restricted by Vegfc maturation causing lymphatic sprouting in certain regions, which is regulated by the metalloproteases ADAMTS3 and ADAMTS14.

Members of the lysyl oxidase (LOX) family catalyze the oxidative deamination of lysine and hydroxylysine residues in collagen and elastin in the initiation step of the formation of covalent cross-links, an essential process for connective tissue maturation. Proteolysis has emerged as an important level of regulation of LOX enzymes with the cleavage of the LOX isoform by metalloproteinases of the BMP1 (bone morphogenetic protein 1) and ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) families as a model example. Lysyl oxidase-like 1 (LOXL1), an isoform associated with pelvic organ prolapse and pseudoexfoliation (PEX) glaucoma, has also been reported to be proteolytically processed by these proteases. However, precise molecular information on these proteolytic events is not available. In this study, using genetic cellular models, along with proteomic analyses, we describe that LOXL1 is processed by BMP1 and ADAMTS14 and identify the processing sites in the LOXL1 protein sequence. Our data show that BMP1 cleaves LOXL1 in a unique location within the pro-peptide region, whereas ADAMTS14 processes LOXL1 in at least three different sites located within the pro-peptide and in the first residues of the catalytic domain. Taken together, these results suggest a complex regulation of LOXL1 function by BMP1- and ADAMTS14-mediated proteolysis where LOXL1 enzymes retaining variable fragments of N-terminal region may display different capabilities.

ADAMTS (A Disintegrin and Metalloproteinase with Thrombospondin motifs) family is a group of secretory proteases involved in the maintenance of central nervous system (CNS) homeostasis and neuronal disease. ADAMTS18 is a member of this family and has been linked to the integrity of the human brain’s white matter. However, the cellular and molecular basis of ADAMTS18 in brain metabolism and homeostasis remains unclear. In this study, a total of 47,719 genes were identified in 8 independent wild type (WT) and Adamts18 knockout (KO) mouse brain samples using brain transcriptomic analysis. The abundance of 100 genes in brain was significantly different between WT and KO mice. ADAMTS18 deficiency resulted in decreased S-adenosine homocysteine hydrolase (SAHH) levels, impaired brain methyl cycle metabolism and dysregulation of neuroinflammatory-related factors (e.g., Lrg1 , and Lcn2 ) in mouse brain. The number and branching complexity of microglia in brain tissue of Adamts18 KO mice were significantly reduced. Adamts18 KO mice also showed poor blood-brain barrier (BBB) integrity. Mechanically, ADAMTS18 deficiency resulted in significant downregulation of Il- 34 , Csf1r , Cx3cl1 , Cx3cr1 , Fn , Tgfb1 , Tgfbr2 , Smad4 and Sall1 genes related to microglia expansion, migration, characteristic development and maintenance. BBB integrity related markers Glut1 , Plvap , Zo- 1 , Occludin or Aqp- 4 were partially dysregulated in the brain tissue of Adamts18 KO mice and significantly deteriorated after LPS stimulation. Collectively, these results shed light on the significance of ADAMTS18 in brain methyl cycle metabolism, neuroinflammatory regulation and BBB structure maintenance.

Fibrosis accompanies most heart diseases and is associated with adverse patient outcomes. Transforming growth factor (TGF)β drives extracellular matrix remodelling and fibrosis in the failing heart. Some members of the ADAMTSL (a disintegrin-like and metalloproteinase domain with thrombospondin type 1 motifs-like) family of secreted glycoproteins bind to matrix microfibrils, and although their function in the heart remains largely unknown, they are suggested to regulate TGFβ activity. The aims of this study were to determine ADAMTSL2 levels in failing hearts, and to elucidate the role of ADAMTSL2 in fibrosis using cultured human cardiac fibroblasts (CFBs). Cardiac ADAMTSL2 mRNA was robustly increased in human and experimental heart failure, and mainly expressed by fibroblasts. Over-expression and treatment with extracellular ADAMTSL2 in human CFBs led to reduced TGFβ production and signalling. Increased ADAMTSL2 attenuated myofibroblast differentiation, with reduced expression of the signature molecules α-smooth muscle actin and osteopontin. Finally, ADAMTSL2 mitigated the pro-fibrotic CFB phenotypes, proliferation, migration and contractility. In conclusion, the extracellular matrix-localized glycoprotein ADAMTSL2 was upregulated in fibrotic and failing hearts of patients and mice. We identified ADAMTSL2 as a negative regulator of TGFβ in human cardiac fibroblasts, inhibiting myofibroblast differentiation and pro-fibrotic properties.