Self-immobilization of coacervate droplets by enzyme-mediated hydrogelation

2021 ◽  
Author(s):  
Yufeng Chen ◽  
Yan-Wen Zhang ◽  
Mei Li ◽  
Songyang Liu ◽  
Xiaohai Yang ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Enzyme Activity ◽  
The Self

An artificial protocell model mimicking stimuli-triggered extracellular matrix formation is demonstrated based on the self-immobilization of coacervate microdroplets. Endogenous enzyme activity within the microdroplets results in the release of Ca2+...

scholarly journals Nanotechnology in the Regeneration of Complex Tissues

2014 ◽  
Vol 5 ◽  
pp. BTRI.S12331 ◽  
Author(s):  
John W. Cassidy
Keyword(s):  
Tissue Engineering ◽  
Stem Cells ◽  
Extracellular Matrix ◽  
Regenerative Medicine ◽  
Modern Medicine ◽  
The Self ◽  
Mechanical Support ◽  
Related Field ◽  
Biomimetic Scaffolds ◽  
Repair Mechanisms

Modern medicine faces a growing crisis as demand for organ transplantations continues to far outstrip supply. By stimulating the body's own repair mechanisms, regenerative medicine aims to reduce demand for organs, while the closely related field of tissue engineering promises to deliver “of-the-self” organs grown from patients' own stem cells to improve supply. To deliver on these promises, we must have reliable means of generating complex tissues. Thus far, the majority of successful tissue engineering approaches have relied on macroporous scaffolds to provide cells with both mechanical support and differentiative cues. In order to engineer complex tissues, greater attention must be paid to nanoscale cues present in a cell's microenvironment. As the extracellular matrix is capable of driving complexity during development, it must be understood and reproduced in order to recapitulate complexity in engineered tissues. This review will summarize current progress in engineering complex tissue through the integration of nanocomposites and biomimetic scaffolds.

scholarly journals A Trypanosoma cruzi-secreted 80 kDa proteinase with specificity for human collagen types I and IV

1997 ◽  
Vol 325 (1) ◽  
pp. 129-137 ◽  
Author(s):  
Jaime Martins SANTANA ◽  
Philippe GRELLIER ◽  
Joseph SCHRÉVEL ◽  
Antonio R. L. TEIXEIRA
Keyword(s):  
Extracellular Matrix ◽  
Enzyme Activity ◽  
Chagas Disease ◽  
Mammalian Cells ◽  
Peptide Sequence ◽  
Proteinase Activity ◽  
Type I ◽  
Collagen Types ◽  
Small Proteins ◽  
Extracellular Matrix Components

Specific interactions between parasites and extracellular matrix components are an important mechanism in the dissemination of Chagas' disease. Binding of the extracellular matrix proteins to Trypanosoma cruzireceptors has been described as a significant step in this phenomenon. In this study, a specific proteinase activity was identified in cell-free extracts of amastigote, trypomastigote and epimastigote forms of T. cruziusing the collagenase fluorogenic substrate N-Suc-Gly-Pro-Leu-Gly-Pro-7-amido-4-methylcoumarin. Isolation of this activity was achieved by a four-step FPLC procedure. Optimal enzyme activity was found to occur at pH 8.0 and was associated with a single T. cruzi80 kDa protein (Tc 80 proteinase) on SDS/PAGE under reducing conditions. An internal peptide sequence of Tc 80 proteinase was obtained (AGDNYTPPE), and no similarity was found to previously described proteinases of T. cruzi. This enzyme activity is strongly inhibited by HgCl2, tosyl-lysylchloromethane (‘TLCK’) p-chloromercuribenzoate and benzyloxycarbonyl-Phe-Ala-diazomethane. The purified enzyme was able to hydrolyse purified human [14C]collagen types I and IV at neutral pH, but not 14C-labelled BSA, rat laminin, rabbit IgG or small proteins such as insulin or cytochrome c. In addition, Tc 80 proteinase activity was found to be secreted by T. cruziforms infective to mammalian cells. Furthermore we demonstrated that purified Tc 80 proteinase mediates native collagen type I hydrolysis in rat mesentery. This feature is compared with that of Clostridium histolyticum collagenase. These findings suggest that Tc 80 proteinase may facilitate T. cruzihost-cell infection by degrading the collagens of the extracellular matrix and could represent a good target for Chagas' disease chemotherapy.

scholarly journals Extracellular Matrix Fibronectin Stimulates the Self-Assembly of Microtissues on Native Collagen Gels

2010 ◽  
Vol 16 (12) ◽  
pp. 3805-3819 ◽  
Author(s):  
Carlos A. Sevilla ◽  
Diane Dalecki ◽  
Denise C. Hocking
Keyword(s):  
Extracellular Matrix ◽  
Self Assembly ◽  
The Self ◽  
Collagen Gels ◽  
Native Collagen

scholarly journals Biochemical and immunohistochemical evidence that in cartilage an alkaline phosphatase is a Ca2+-binding glycoprotein.

1986 ◽  
Vol 103 (4) ◽  
pp. 1615-1623 ◽  
Author(s):  
B de Bernard ◽  
P Bianco ◽  
E Bonucci ◽  
M Costantini ◽  
G C Lunazzi ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Alkaline Phosphatase ◽  
Enzyme Activity ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Protein A ◽  
Matrix Vesicles ◽  
Immune Reactivity ◽  
The Matrix ◽  
Immunohistochemical Evidence

A glycoprotein that exhibits alkaline phosphatase activity and binds Ca2+ with high affinity has been extracted and purified from cartilage matrix vesicles by fast protein liquid chromatography. Antibodies against this glycoprotein were used to analyze its distribution in chondrocytes and in the matrix of calcifying cartilage. Under the light microscope, using immunoperoxidase or immunofluorescence techniques, the glycoprotein is localized in chondrocytes of the resting zone. At this level, the extracellular matrix does not show any reaction. In the cartilage plate, between the proliferating and the hypertrophic region, a weak immune reactivity is seen in the cytoplasm, whereas in the intercolumnar matrix the collagen fibers appear clearly stained. Stained granular structures, distributed with a pattern similar to that of matrix vesicles, are also visible. Calcified matrix is the most stained area. These results were confirmed under the electron microscope using both immunoperoxidase and protein A-gold techniques. In parallel studies, enzyme activity was also analyzed by histochemical methods. Whereas resting cartilage, the intercellular matrix of the resting zone, and calcified matrix do not exhibit any enzyme activity, the zones of maturing and hypertrophic chondrocytes are highly reactive. Some weak reactivity is also shown by chondrocytes of the resting zone. The observation that this glycoprotein (which binds Ca2+ and has alkaline phosphatase activity) is synthesized in chondrocytes and is exported to the extracellular matrix at the time when calcification begins, suggests that it plays a specific role in the process of calcification.

scholarly journals Lysyl Oxidase Gene Expression and Enzyme Activity in the Rat Ovary: Regulation by Follicle-Stimulating Hormone, Androgen, and Transforming Growth Factor-β Superfamily Members in Vitro

Endocrinology ◽  
2003 ◽  
Vol 144 (1) ◽  
pp. 154-162 ◽  
Author(s):  
Christopher R. Harlow ◽  
Mick Rae ◽  
Lindsay Davidson ◽  
Philip C. Trackman ◽  
Stephen G. Hillier
Keyword(s):  
Extracellular Matrix ◽  
Enzyme Activity ◽  
Granulosa Cells ◽  
Transforming Growth Factor ◽  
Lysyl Oxidase ◽  
Enzymatic Reaction ◽  
Follicular Development ◽  
Fold Increase ◽  
Oxidase Gene

Abstract Lysyl oxidase (LOX) catalyzes the final enzymatic reaction required for cross-linking of collagen and elastin fibers and therefore has a crucial role in regulating the formation and maintenance of extracellular matrix in the ovary. LOX mRNA is abundantly expressed in rat granulosa cells. To examine how regulation of LOX in the ovary might influence follicular development, we studied LOX mRNA expression and enzyme activity in rat granulosa cells from late preantral/early antral follicles in vitro. FSH dose dependently inhibited LOX mRNA and enzyme activity (50% reduction at 10 ng/ml) in vitro, and FSH action was mimicked by 8-bromo-cAMP, suggesting FSH action via elevation of cAMP. Dihydrotestosterone alone enhanced LOX mRNA and enzyme activity, but potentiated the effect of FSH, causing a further reduction. TGFβ1 alone dose dependently enhanced LOX mRNA (5-fold increase at 10 ng/ml) and activity (1.5-fold increase). FSH dose dependently inhibited the increase in LOX mRNA and activity caused by TGFβ1 (by up to 84% and 80%, respectively). Growth differentiation factor-9 (GDF-9) and activin A, at the same concentration as TGFβ1 (10 ng/ml), stimulated LOX mRNA and activity within 6 h, although overall expression was higher at 48 h. All three factors when combined with FSH further reduced both mRNA and enzyme activity (by up to 60%) compared with FSH alone. These findings indicate control of LOX at endocrine, paracrine, and autocrine levels within the ovary and suggest coordinated regulation of ovarian extracellular matrix during follicular development, with FSH determining whether local factors act as stimulators or inhibitors of LOX.

scholarly journals Engineering Tissues without the Use of a Synthetic Scaffold: A Twenty-Year History of the Self-Assembly Method

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Ingrid Saba ◽  
Weronika Jakubowska ◽  
Stéphane Bolduc ◽  
Stéphane Chabaud
Keyword(s):  
Extracellular Matrix ◽  
Self Assembly ◽  
Large Scale ◽  
Dermal Fibroblasts ◽  
The Self ◽  
Production Costs ◽  
Scale Production ◽  
Assembly Method ◽  
Assembly Technique

Twenty years ago, Dr. François A. Auger, the founder of the Laboratory of Experimental Organogenesis (LOEX), introduced the self-assembly technique. This innovative technique relies on the ability of dermal fibroblasts to produce and assemble their own extracellular matrix, differing from all other tissue-engineering techniques that use preformed synthetic scaffolds. Nevertheless, the use of the self-assembly technique was limited for a long time due to its main drawbacks: time and cost. Recent scientific breakthroughs have addressed these limitations. New protocol modifications that aim at increasing the rate of extracellular matrix formation have been proposed to reduce the production costs and laboratory handling time of engineered tissues. Moreover, the introduction of vascularization strategies in vitro permits the formation of capillary-like networks within reconstructed tissues. These optimization strategies enable the large-scale production of inexpensive native-like substitutes using the self-assembly technique. These substitutes can be used to reconstruct three-dimensional models free of exogenous materials for clinical and fundamental applications.

scholarly journals Kelainan Matriks Ekstraseluler Agrekan pada Osteoarthritis

2020 ◽  
Vol 9 (1) ◽  
pp. 67-80
Author(s):  
Umiatin Umiatin ◽  
Jeanne A Diwinata Pawitan
Keyword(s):  
Extracellular Matrix ◽  
Enzyme Activity ◽  
Molecular Mechanisms ◽  
Cartilage Damage ◽  
Type Ii Collagen ◽  
Joint Disease ◽  
Joint Cartilage ◽  
Keywords Osteoarthritis ◽  
A Disintegrin And Metalloproteinase ◽  
Thrombospondin Motif

Abstrak Osteoarthritis (OA) merupakan penyakit sendi dengan prevalensi paling tinggi yang menyebabkan nyeri kronis dan disabilitas. Berbagai faktor antara lain faktor mekanik, biokimia dan faktor enzimatik berperan dalam perkembangan OA. Perkembangan OA dicirikan oleh degradasi berlebihan pada agrekan dalam matriks ekstraseluler tulang rawan sendi. Agrekan berfungsi menyediakan fleksibilitas, viskoelastisitas dan kompresibilitas jaringan. Struktur agrekan tidak konstan sepanjang hidup, namun mengalami perubahan yang disebabkan oleh aktivitas sintesis maupun degradasi. Degradasi agrekan merupakan penanda awal kerusakan tulang rawan sendi pada OA, yang diikuti oleh kerusakan kolagen tipe II. Sejauh ini mekanisme molekulernya belum diketahui pasti, sehingga diperlukan penelitian lebih lanjut mengenai mekanisme dan penyebab kerusakan agrekan. Tulisan ini merupakan suatu kajian naratif berdasarkan artikel dari jurnal nasional dan internasional yang bertujuan untuk memberikan informasi mengenai agrekan meliputi struktur, fungsi, dan faktor-faktor yang berperan pada perubahan struktur agrekan yang menginduksi terjadinya OA. Hasil kajian menunjukkan bahwa perubahan struktur agrekan erat kaitannya dengan perubahan fungsi mekanik tulang rawan sendi. Perubahan ini terjadi terutama karena degradasi yang disebabkan oleh aktivitas enzim, dari keluarga matriks metalloprotease (MMP) dan a disintegrin and metalloproteinase with thrombospondin motif (ADAMTS). Dari kajian ini disimpulkan bahwa degradasi agrekan karena aktivitas enzim berperan penting dalam perkembangan OA, sehingga perlu dilakukan penelitian untuk mencari inhibitor enzim MMP dan ADAMTS sebagai agen terapeutik untuk menghambat perkembangan dan progresivitas OA. Kata kunci: osteoarthritis, matriks ektraseluler, agrekan, degradasi. Abstract Osteoarthritis (OA) is a joint disease with the highest prevalence and a major cause of chronic pain and disability. Many factors such as mechanical, biochemical, and enzymatic factors are involved in OA development. The development of OA is characterized by excessive degradation of aggrecan in the extracellular matrix of articular cartilage, which functions to provide flexibility, viscoelasticity, and tissue compressibility. The structure of aggrecan is not constant throughout life but undergoes changes caused by synthesis and degradation activities. Aggrecan degradation is an early marker of joint cartilage damage in OA, followed by type II collagen damage. However, the molecular mechanisms are not completely understood, so further research is needed on the mechanisms and causes of aggrecan damage. Here we provide a narrative review based on articles from national and international journals to describe the structure, function, and factors that contribute to the degradation of aggrecan. The results of the study show that changes in the structure of aggrecan are closely related to changes in the mechanical function of joint cartilage. This change occurs mainly due to degradation caused by enzyme activity, a family of matrix metalloproteinase (MMP) and a disintegrin and metalloproteinase with thrombospondin motif (ADAMTS). The present study concludes that aggrecan degradation caused by enzyme activity was very crucial in the development of OA, it was needed to find MMP and ADAMTS inhibitors as a therapeutic agent to prevent the development and progression of OA. Keywords: osteoarthritis, extracellular matrix, aggrecan, degradation

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