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 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 Native cross-links in collagen fibrils induce resistance to human synovial collagenase

1979 ◽  
Vol 181 (3) ◽  
pp. 639-645 ◽  
Author(s):  
C A Vater ◽  
E D Harris ◽  
R C Siegel
Keyword(s):  
Lysyl Oxidase ◽  
Collagen Fibrils ◽  
Bone Collagen ◽  
Collagen Molecule ◽  
Cross Linking ◽  
Pathological Conditions ◽  
Insoluble Material ◽  
Induce Resistance ◽  
Cross Links

A model system consisting of highly purified lysyl oxidase and reconstituted lathyritic chick bone collagen fibrils was used to study the effect of collagen cross-linking on collagen degradation by mammalian collagenase. The results indicate that synthesis of approx. 0.1 Schiff-base cross-link per collagen molecule results in a 2–3-fold resistance to human synovial collagenase when compared with un-cross-linked controls or samples incubated in the presence of beta-aminopropionitrile to inhibit cross-linking. These results confirm previous studies utilizing artificially cross-linked collagens, or collagens isolated as insoluble material after cross-linking in vivo, and suggest that increased resistance to collagenase may be one of the earliest effects of cross-linking in vivo. The extent of intermolecular cross-linking among collagen fibrils may provide a mechanism for regulating the rate of collagen catabolism relative to synthesis in normal and pathological conditions.

scholarly journals Genetic Susceptibility and Protein Expression of Extracellular Matrix Turnover-Related Genes in Oral Submucous Fibrosis

2020 ◽  
Vol 21 (21) ◽  
pp. 8104
Author(s):  
Ru-Hsiu Cheng ◽  
Yi-Ping Wang ◽  
Julia Yu-Fong Chang ◽  
Yu-Hwa Pan ◽  
Mei-Chi Chang ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Oral Cancer ◽  
Genetic Susceptibility ◽  
Molecular Mechanisms ◽  
Lysyl Oxidase ◽  
Oral Submucous Fibrosis ◽  
Tissue Inhibitors Of Metalloproteinases ◽  
Contributing Factors ◽  
Plasminogen Activator Inhibitor 1 ◽  
Submucous Fibrosis

Betel quid (BQ) chewing increased the risk of oral cancer and oral submucous fibrosis (OSMF), an oral premalignant disorder (OPMD) with malignant transformation potential. BQ components such as areca nut (AN), trauma by coarse AN fiber, catechin, copper, alkaloids, stimulated reactive oxygen species (ROS), inflammation and cytotoxicity are suggested to be the contributing factors. They may induce tissue inflammation, proliferation of fibroblasts and collagen deposition, myofibroblast differentiation and contraction, collagen cross-links and inhibit collagen phagocytosis, finally leading to the development of OSMF and oral cancer. These events are mediated by BQ components-induced changes of extracellular matrix (ECM) turnover via regulation of TGF-β1, plasminogen activator inhibitor-1 (PAI-1), cystatin, lysyl oxidase (LOX) and tissue inhibitors of metalloproteinases (TIMPs) and metalloproteinases (MMPs). Genetic susceptibility is also involved in these disease processes. Further understanding the molecular mechanisms of BQ-induced OSMF and oral cancer can be helpful for future disease prevention and treatment.

scholarly journals Cross-linking reveals laminin coiled-coil architecture

2016 ◽  
Vol 113 (47) ◽  
pp. 13384-13389 ◽  
Author(s):  
Gad Armony ◽  
Etai Jacob ◽  
Toot Moran ◽  
Yishai Levin ◽  
Tevie Mehlman ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Self Assembly ◽  
Quaternary Structure ◽  
Coiled Coil ◽  
Surface Proteins ◽  
Cross Linking ◽  
Single Particle Reconstruction ◽  
Cross Links ◽  
Particle Reconstruction ◽  
Key Questions

Laminin, an ∼800-kDa heterotrimeric protein, is a major functional component of the extracellular matrix, contributing to tissue development and maintenance. The unique architecture of laminin is not currently amenable to determination at high resolution, as its flexible and narrow segments complicate both crystallization and single-particle reconstruction by electron microscopy. Therefore, we used cross-linking and MS, evaluated using computational methods, to address key questions regarding laminin quaternary structure. This approach was particularly well suited to the ∼750-Å coiled coil that mediates trimer assembly, and our results support revision of the subunit order typically presented in laminin schematics. Furthermore, information on the subunit register in the coiled coil and cross-links to downstream domains provide insights into the self-assembly required for interaction with other extracellular matrix and cell surface proteins.

scholarly journals Characterization of Genipin-Modified Dentin Collagen

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Hiroko Nagaoka ◽  
Hideaki Nagaoka ◽  
Ricardo Walter ◽  
Lee W. Boushell ◽  
Patricia A. Miguez ◽  
...  
Keyword(s):  
Amino Acid ◽  
Lysyl Oxidase ◽  
Biomechanical Properties ◽  
Biochemical Properties ◽  
Cross Linking ◽  
Dependent Manner ◽  
Cross Link ◽  
Concentration Dependent Manner ◽  
Cross Links ◽  
Dentin Collagen

Application of biomodification techniques to dentin can improve its biochemical and biomechanical properties. Several collagen cross-linking agents have been reported to strengthen the mechanical properties of dentin. However, the characteristics of collagen that has undergone agent-induced biomodification are not well understood. The objective of this study was to analyze the effects of a natural cross-linking agent, genipin (GE), on dentin discoloration, collagen stability, and changes in amino acid composition and lysyl oxidase mediated natural collagen cross-links. Dentin collagen obtained from extracted bovine teeth was treated with three different concentrations of GE (0.01%, 0.1%, and 0.5%) for several treatment times (0–24 h). Changes in biochemical properties of NaB3H4-reduced collagen were characterized by amino acid and cross-link analyses. The treatment of dentin collagen with GE resulted in a concentration- and time-dependent pigmentation and stability against bacterial collagenase. The lysyl oxidase-mediated trivalent mature cross-link, pyridinoline, showed no difference among all groups while the major divalent immature cross-link, dehydro-dihydroxylysinonorleucine/its ketoamine in collagen treated with 0.5% GE for 24 h, significantly decreased compared to control (P< 0.05). The newly formed GE-induced cross-links most likely involve lysine and hydroxylysine residues of collagen in a concentration-dependent manner. Some of these cross-links appear to be reducible and stabilized with NaB3H4.

scholarly journals MaXLinker: Proteome-wide Cross-link Identifications with High Specificity and Sensitivity

2019 ◽  
Vol 19 (3) ◽  
pp. 554-568 ◽  
Author(s):  
Kumar Yugandhar ◽  
Ting-Yi Wang ◽  
Alden King-Yung Leung ◽  
Michael Charles Lanz ◽  
Ievgen Motorykin ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Search Engine ◽  
Protein Interactions ◽  
Molecular Mechanisms ◽  
Cross Linking ◽  
Interaction Patterns ◽  
Protein Protein Interactions ◽  
Cross Link ◽  
Wide Cross ◽  
Cross Links

Protein-protein interactions play a vital role in nearly all cellular functions. Hence, understanding their interaction patterns and three-dimensional structural conformations can provide crucial insights about various biological processes and underlying molecular mechanisms for many disease phenotypes. Cross-linking mass spectrometry (XL-MS) has the unique capability to detect protein-protein interactions at a large scale along with spatial constraints between interaction partners. The inception of MS-cleavable cross-linkers enabled the MS2-MS3 XL-MS acquisition strategy that provides cross-link information from both MS2 and MS3 level. However, the current cross-link search algorithm available for MS2-MS3 strategy follows a “MS2-centric” approach and suffers from a high rate of mis-identified cross-links. We demonstrate the problem using two new quality assessment metrics [“fraction of mis-identifications” (FMI) and “fraction of interprotein cross-links from known interactions” (FKI)]. We then address this problem, by designing a novel “MS3-centric” approach for cross-link identification and implementing it as a search engine named MaXLinker. MaXLinker outperforms the currently popular search engine with a lower mis-identification rate, and higher sensitivity and specificity. Moreover, we performed human proteome-wide cross-linking mass spectrometry using K562 cells. Employing MaXLinker, we identified a comprehensive set of 9319 unique cross-links at 1% false discovery rate, comprising 8051 intraprotein and 1268 interprotein cross-links. Finally, we experimentally validated the quality of a large number of novel interactions identified in our study, providing a conclusive evidence for MaXLinker's robust performance.

scholarly journals LOXL2—A New Target in Antifibrogenic Therapy?

2019 ◽  
Vol 20 (7) ◽  
pp. 1634 ◽  
Author(s):  
Angela Puente ◽  
Jose Fortea ◽  
Joaquin Cabezas ◽  
Maria Arias Loste ◽  
Paula Iruzubieta ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Liver Fibrosis ◽  
Animal Studies ◽  
Molecular Mechanisms ◽  
Lysyl Oxidase ◽  
Portal Pressure ◽  
Induce Cell Cycle Arrest ◽  
Cell Functions ◽  
Extracellular Matrix Components ◽  
Matrix Components

The concept of liver fibrosis and cirrhosis being static and therefore irreversible is outdated. Indeed, both human and animal studies have shown that fibrogenesis is a dynamic and potentially reversible process that can be modulated either by stopping its progression and/or by promoting its resolution. Therefore, the study of the molecular mechanisms involved in the pathogenesis of liver fibrosis is critical for the development of future antifibrotic therapies. The fibrogenesis process, common to all forms of liver injury, is characterized by the increased deposition of extracellular matrix components (EMCs), including collagen, proteoglycans, and glycoproteins (laminin and fibronectin 2). These changes in the composition of the extracellular matrix components alter their interaction with cell adhesion molecules, influencing the modulation of cell functions (growth, migration, and gene expression). Hepatic stellate cells and Kupffer cells (liver macrophages) are the key fibrogenic effectors. The antifibrogenic mechanism starts with the activation of Ly6Chigh macrophages, which can differentiate into macrophages with antifibrogenic action. The research of biochemical changes affecting fibrosis irreversibility has identified lysyl oxidase-like 2 (LOXL2), an enzyme that promotes the network of collagen fibers of the extracellular matrix. LOXL2 inhibition can decrease cell numbers, proliferation, colony formations, and cell growth, and it can induce cell cycle arrest and increase apoptosis. The development of a new humanized IgG4 monoclonal antibody against LOXL2 could open the window of a new antifibrogenic treatment. The current therapeutic target in patients with liver cirrhosis should focus (after the eradication of the causal agent) on the development of new antifibrogenic drugs. The development of these drugs must meet three premises: Patient safety, in non-cirrhotic phases, down-staging or at least stabilization and slowing the progression to cirrhosis must be achieved; whereas in the cirrhotic stage, the objective should be to reduce fibrosis and portal pressure.

scholarly journals High-density chemical cross-linking for modeling protein interactions

2019 ◽  
Vol 117 (1) ◽  
pp. 93-102 ◽  
Author(s):  
Julian Mintseris ◽  
Steven P. Gygi
Keyword(s):  
Mass Spectrometry ◽  
Method Development ◽  
Conformational Dynamics ◽  
Complex Function ◽  
Computational Cost ◽  
Dimensional Structure ◽  
Cross Linking ◽  
Proteasome Subunits ◽  
Cross Links ◽  
Chemical Cross Linking

Detailed mechanistic understanding of protein complex function is greatly enhanced by insights from its 3-dimensional structure. Traditional methods of protein structure elucidation remain expensive and labor-intensive and require highly purified starting material. Chemical cross-linking coupled with mass spectrometry offers an alternative that has seen increased use, especially in combination with other experimental approaches like cryo-electron microscopy. Here we report advances in method development, combining several orthogonal cross-linking chemistries as well as improvements in search algorithms, statistical analysis, and computational cost to achieve coverage of 1 unique cross-linked position pair for every 7 amino acids at a 1% false discovery rate. This is accomplished without any peptide-level fractionation or enrichment. We apply our methods to model the complex between a carbonic anhydrase (CA) and its protein inhibitor, showing that the cross-links are self-consistent and define the interaction interface at high resolution. The resulting model suggests a scaffold for development of a class of protein-based inhibitors of the CA family of enzymes. We next cross-link the yeast proteasome, identifying 3,893 unique cross-linked peptides in 3 mass spectrometry runs. The dataset includes 1,704 unique cross-linked position pairs for the proteasome subunits, more than half of them intersubunit. Using multiple recently solved cryo-EM structures, we show that observed cross-links reflect the conformational dynamics and disorder of some proteasome subunits. We further demonstrate that this level of cross-linking density is sufficient to model the architecture of the 19-subunit regulatory particle de novo.

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