scholarly journals A matricellular protein fibulin-4 is essential for the activation of lysyl oxidase

2020 ◽  
Vol 6 (48) ◽  
pp. eabc1404
Author(s):  
Kazuo Noda ◽  
Kaori Kitagawa ◽  
Takao Miki ◽  
Masahito Horiguchi ◽  
Tomoya O. Akama ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Lysyl Oxidase ◽  
Copper Ion ◽  
Pivotal Role ◽  
Cross Linking ◽  
Matricellular Protein ◽  
Ion Transfer ◽  
Wild Type ◽  
Copper Transporter ◽  
Golgi Network

Fibulin-4 is a matricellular protein required for extracellular matrix (ECM) assembly. Mice deficient in fibulin-4 (Fbln4−/−) have disrupted collagen and elastin fibers and die shortly after birth from aortic and diaphragmatic rupture. The function of fibulin-4 in ECM assembly, however, remains elusive. Here, we show that fibulin-4 is required for the activity of lysyl oxidase (LOX), a copper-containing enzyme that catalyzes the covalent cross-linking of elastin and collagen. LOX produced by Fbln4−/− cells had lower activity than LOX produced by wild-type cells due to the absence of lysine tyrosyl quinone (LTQ), a unique cofactor required for LOX activity. Our studies showed that fibulin-4 is required for copper ion transfer from the copper transporter ATP7A to LOX in the trans-Golgi network (TGN), which is a necessary step for LTQ formation. These results uncover a pivotal role for fibulin-4 in the activation of LOX and, hence, in ECM assembly.

scholarly journals Effects of Copper and Cross-Linking on the Extracellular Matrix of Tissue-Engineered Arteries

2005 ◽  
Vol 14 (6) ◽  
pp. 367-374 ◽  
Author(s):  
Shannon L. M. Dahl ◽  
Robert B. Rucker ◽  
Laura E. Niklason
Keyword(s):  
Extracellular Matrix ◽  
Collagen Fibril ◽  
Lysyl Oxidase ◽  
Copper Ion ◽  
Ion Concentration ◽  
Cross Linking ◽  
Cross Link ◽  
Ion Concentrations ◽  
Mechanical Strengths ◽  
Link Formation

In many cases, the mechanical strengths of tissue-engineered arteries do not match the mechanical strengths of native arteries. Ultimate arterial strength is primarily dictated by collagen in the extracellular matrix, but collagen in engineered arteries is not as dense, as organized, or as mature as collagen in native arteries. One step in the maturation process of collagen is the formation of hydroxylysyl pyridinoline (HP) cross-links between and within collagen molecules. HP cross-link formation, which is triggered by the copper-activated enzyme lysyl oxidase, greatly increases collagen fibril stability and enhances tissue strength. Increased cross-link formation, in addition to increased collagen production, may yield a stronger engineered tissue. In this article, the effect of increasing culture medium copper ion concentration on engineered arterial tissue composition and mechanics was investigated. Engineered vessels grown in low copper ion concentrations for the first 4 weeks of culture, followed by higher copper ion concentrations for the last 3 weeks of culture, had significantly elevated levels of cross-link formation compared to those grown in low copper ion concentrations. In contrast, vessels grown in high copper ion concentrations throughout culture failed to develop higher collagen cross-link densities than those grown in low copper ion concentrations. Although the additional cross-linking of collagen in engineered vessels may provide collagen fibril stability and resistance to proteolysis, it failed to enhance global tissue strength.

Lysyl oxidases: from enzyme activity to extracellular matrix cross-links

2019 ◽  
Vol 63 (3) ◽  
pp. 349-364 ◽  
Author(s):  
Sylvain D. Vallet ◽  
Sylvie Ricard-Blum
Keyword(s):  
Extracellular Matrix ◽  
Molecular Mechanisms ◽  
Catalytic Domain ◽  
Lysyl Oxidase ◽  
Dimensional Structure ◽  
Cross Linking ◽  
Copper Binding ◽  
Molecular Features ◽  
Ecm Proteins ◽  
Cross Links

Abstract The lysyl oxidase family comprises five members in mammals, lysyl oxidase (LOX) and four lysyl oxidase like proteins (LOXL1-4). They are copper amine oxidases with a highly conserved catalytic domain, a lysine tyrosylquinone cofactor, and a conserved copper-binding site. They catalyze the first step of the covalent cross-linking of the extracellular matrix (ECM) proteins collagens and elastin, which contribute to ECM stiffness and mechanical properties. The role of LOX and LOXL2 in fibrosis, tumorigenesis, and metastasis, including changes in their expression level and their regulation of cell signaling pathways, have been extensively reviewed, and both enzymes have been identified as therapeutic targets. We review here the molecular features and three-dimensional structure/models of LOX and LOXLs, their role in ECM cross-linking, and the regulation of their cross-linking activity by ECM proteins, proteoglycans, and by inhibitors. We also make an overview of the major ECM cross-links, because they are the ultimate molecular readouts of LOX/LOXL activity in tissues. The recent 3D model of LOX, which recapitulates its known structural and biochemical features, will be useful to decipher the molecular mechanisms of LOX interaction with its various substrates, and to design substrate-specific inhibitors, which are potential antifibrotic and antitumor drugs.

scholarly journals Targeted Deletion of the SPARC Gene Accelerates Disc Degeneration in the Aging Mouse

2005 ◽  
Vol 53 (9) ◽  
pp. 1131-1138 ◽  
Author(s):  
Helen E. Gruber ◽  
E. Helene Sage ◽  
H. James Norton ◽  
Sarah Funk ◽  
Jane Ingram ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Connective Tissue ◽  
Matricellular Protein ◽  
Secreted Protein ◽  
Wild Type ◽  
Variable Size ◽  
Targeted Deletion ◽  
Ultrastructural Studies ◽  
Aging Mouse ◽  
Lower Lumbar

SPARC (secreted protein, acidic, and rich in cysteine) is a matricellular protein that is present in the intervertebral disc; in man, levels of SPARC decrease with aging and degeneration. In this study, we asked whether targeted deletion of SPARC in the mouse influenced disc morphology. SPARC-null and wild-type (WT) mice were studied at 0.3–21 months of age. Radiologic examination of spines from 2-month-old SPARC-null mice revealed wedging, endplate calcification, and sclerosis, features absent in age-matched WT spines. Discs from 3-month-old SPARC-null mice had a greater number of annulus cells than those of WT animals (1884.6 ± 397.9 [mean ± SD] vs 1500.2 ± 188.2, p=0.031). By 19 months discs from SPARC-null mice contained fewer cells than WT counterparts (1383.6 ± 363.3 vs 1466.8 ± 148.0, p=0.033). Histology of midsagittal spines showed herniations of lower lumbar discs of SPARC-null mice ages 14–19 months; in contrast, no herniations were seen in WT age-matched animals. Ultrastructural studies showed uniform collagen fibril diameters in the WT annulus, whereas in SPARC-null disc fibrils were of variable size with irregular margins. Consistent with the connective tissue deficits observed in other tissues of SPARC-null mice, our findings support a fundamental role for SPARC in the production, assembly, or maintenance of the disc extracellular matrix.

scholarly journals Fibulin-4, a matricellular protein, is essential for the activity of lysyl oxidase, a key enzyme for cross-linking collagens and elastin

2018 ◽  
Vol WCP2018 (0) ◽  
pp. PO2-3-24
Author(s):  
Tomoyuki Nakamura ◽  
Kaori Kitagawa ◽  
Kazuo Noda ◽  
Mitsuo Yamauchi ◽  
Yasumitsu Ogra ◽  
...  
Keyword(s):  
Lysyl Oxidase ◽  
Cross Linking ◽  
Matricellular Protein ◽  
Key Enzyme

scholarly journals Copper, lysyl oxidase, and extracellular matrix protein cross-linking

1998 ◽  
Vol 67 (5) ◽  
pp. 996S-1002S ◽  
Author(s):  
R B Rucker ◽  
T Kosonen ◽  
M S Clegg ◽  
A E Mitchell ◽  
B R Rucker ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Matrix Protein ◽  
Lysyl Oxidase ◽  
Extracellular Matrix Protein ◽  
Cross Linking ◽  
Protein Cross Linking

scholarly journals TGFβ-1 Induced Cross-Linking of the Extracellular Matrix of Primary Human Dermal Fibroblasts

2021 ◽  
Vol 22 (3) ◽  
pp. 984
Author(s):  
Mariya E. Semkova ◽  
J. Justin Hsuan
Keyword(s):  
Extracellular Matrix ◽  
Lysyl Oxidase ◽  
Transglutaminase 2 ◽  
Dermal Fibroblasts ◽  
Cross Linking ◽  
Human Dermal Fibroblasts ◽  
Tgfβ Signalling ◽  
A Cell ◽  
Cross Links

Excessive cross-linking is a major factor in the resistance to the remodelling of the extracellular matrix (ECM) during fibrotic progression. The role of TGFβ signalling in impairing ECM remodelling has been demonstrated in various fibrotic models. We hypothesised that increased ECM cross-linking by TGFβ contributes to skin fibrosis in Systemic Sclerosis (SSc). Proteomics was used to identify cross-linking enzymes in the ECM of primary human dermal fibroblasts, and to compare their levels following treatment with TGFβ-1. A significant upregulation and enrichment of lysyl-oxidase-like 1, 2 and 4 and transglutaminase 2 were found. Western blotting confirmed the upregulation of lysyl hydroxylase 2 in the ECM. Increased transglutaminase activity in TGFβ-1 treated ECM was revealed from a cell-based assay. We employed a mass spectrometry-based method to identify alterations in the ECM cross-linking pattern caused by TGFβ-1. Cross-linking sites were identified in collagens I and V, fibrinogen and fibronectin. One cross-linking site in fibrinogen alpha was found only in TGFβ-treated samples. In conclusion, we have mapped novel cross-links between ECM proteins and demonstrated that activation of TGFβ signalling in cultured dermal fibroblasts upregulates multiple cross-linking enzymes in the ECM.

scholarly journals Lysyl-Oxidase Dependent Extracellular Matrix Stiffness in Hodgkin Lymphomas: Mechanical and Topographical Evidence

Cancers ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 259
Author(s):  
Massimo Alfano ◽  
Irene Locatelli ◽  
Cristina D’Arrigo ◽  
Marco Mora ◽  
Giovanni Vozzi ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Young’S Modulus ◽  
Lysyl Oxidase ◽  
Young's Modulus ◽  
Polarized Light ◽  
Cross Linking ◽  
Low Elastic Modulus ◽  
Extracellular Matrix Stiffness ◽  
Follicular Lymphomas ◽  
Collagen Cross Linking

Purpose: The biochemical composition and architecture of the extracellular matrix (ECM) is known to condition development and invasiveness of neoplasms. To clarify this point, we analyzed ECM stiffness, collagen cross-linking and anisotropy in lymph nodes (LN) of Hodgkin lymphomas (HL), follicular lymphomas (FL) and diffuse large B-cell lymphomas (DLBCL), compared with non-neoplastic LN (LDN). Methods and Results: We found increased elastic (Young’s) modulus in HL and advanced FL (grade 3A) over LDN, FL grade 1–2 and DLBCL. Digital imaging evidenced larger stromal areas in HL, where increased collagen cross-linking was found; in turn, architectural modifications were documented in FL3A by scanning electron microscopy and enhanced anisotropy by polarized light microscopy. Interestingly, HL expressed high levels of lysyl oxidase (LOX), an enzyme responsible for collagen cross-linking. Using gelatin scaffolds fabricated with a low elastic modulus, comparable to that of non-neoplastic tissues, we demonstrated that HL LN-derived mesenchymal stromal cells and HL cells increased the Young’s modulus of the extracellular microenvironment through the expression of LOX. Indeed, LOX inhibition by β-aminopropionitrile prevented the gelatin stiffness increase. Conclusions: These data indicate that different mechanical, topographical and/or architectural modifications of ECM are detectable in human lymphomas and are related to their histotype and grading.

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