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1.
Int J Mol Sci ; 23(8)2022 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-35456902

RESUMO

As essential components of our connective tissues, elastic fibres give tissues such as major blood vessels, skin and the lungs their elasticity. Their formation is complex and co-ordinately regulated by multiple factors. In this review, we describe key players in elastogenesis: fibrillin-1, tropoelastin, latent TGFß binding protein-4, and fibulin-4 and -5. We summarise their roles in elastogenesis, discuss the effect of their mutations on relevant diseases, and describe their interactions involved in forming the elastic fibre network. Moreover, we look into their roles in wound repair for a better understanding of their potential application in tissue regeneration.


Assuntos
Tecido Elástico , Proteínas da Matriz Extracelular , Tecido Conjuntivo/metabolismo , Tecido Elástico/metabolismo , Proteínas da Matriz Extracelular/metabolismo , Proteínas de Ligação a TGF-beta Latente/metabolismo , Tropoelastina/genética , Tropoelastina/metabolismo , Cicatrização/genética
2.
Soft Matter ; 18(16): 3257-3266, 2022 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-35404375

RESUMO

Elastic fiber assembly is a complex process that requires the coacervation and cross-linking of the protein building block tropoelastin. To date, the order, timing, and interplay of coacervation and crosslinking is not completely understood, despite a great number of advances into understanding the molecular structure and functions of the many proteins involved in elastic fiber assembly. With a simple in vitro model using elastin-like polypeptides and the natural chemical crosslinker genipin, we demonstrate the strong influence of the timing and kinetics of crosslinking reaction on the coacervation, crosslinking extent, and resulting morphology of elastin. We also outline a method for analyzing elastin droplet network formation as a heuristic for measuring the propensity for elastic fiber formation. From this we show that adding crosslinker during peak coacervation dramatically increases the propensity for droplet network formation.


Assuntos
Elastina , Tropoelastina , Elastina/química , Cinética , Peptídeos/química , Tropoelastina/química , Tropoelastina/metabolismo
3.
Int J Mol Sci ; 23(3)2022 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-35163482

RESUMO

Elastin represents the structural component of the extracellular matrix providing elastic recoil to tissues such as skin, blood vessels and lungs. Elastogenic cells secrete soluble tropoelastin monomers into the extracellular space where these monomers associate with other matrix proteins (e.g., microfibrils and glycoproteins) and are crosslinked by lysyl oxidase to form insoluble fibres. Once elastic fibres are formed, they are very stable, highly resistant to degradation and have an almost negligible turnover. However, there are circumstances, mainly related to inflammatory conditions, where increased proteolytic degradation of elastic fibres may lead to consequences of major clinical relevance. In severely affected COVID-19 patients, for instance, the massive recruitment and activation of neutrophils is responsible for the profuse release of elastases and other proteolytic enzymes which cause the irreversible degradation of elastic fibres. Within the lungs, destruction of the elastic network may lead to the permanent impairment of pulmonary function, thus suggesting that elastases can be a promising target to preserve the elastic component in COVID-19 patients. Moreover, intrinsic and extrinsic factors additionally contributing to damaging the elastic component and to increasing the spread and severity of SARS-CoV-2 infection are reviewed.


Assuntos
COVID-19/metabolismo , Elastina/fisiologia , Matriz Extracelular/fisiologia , Animais , Tecido Elástico/metabolismo , Elastina/metabolismo , Proteínas da Matriz Extracelular/metabolismo , Armadilhas Extracelulares/metabolismo , Fibrilinas/metabolismo , Humanos , Pulmão/patologia , Microfibrilas/metabolismo , Proteínas dos Microfilamentos/metabolismo , Neutrófilos , Proteína-Lisina 6-Oxidase/metabolismo , SARS-CoV-2/patogenicidade , Tropoelastina/metabolismo
4.
BMC Oral Health ; 21(1): 588, 2021 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-34798886

RESUMO

BACKGROUND: Oral submucous fibrosis (OSF), distinguished by abnormal collagen deposition, is a potentially malignant disorder with 4.2% (95% CI 2.7-5.6%) of malignant transformation and rising global prevalence. However, the precise pathogenesis and effective treatment remain elusive and controversial despite the abundance of literature on this topic. Therefore, it is crucial to explore the clinicopathological characteristics and potential markers for the diagnosis and prognosis of OSF. The objective of this study was to evaluate the influence and correlation of Microfibrillar-associated protein 4 (MFAP4) and tropoelastin (TE) in the development of OSF patients. MATERIAL AND METHODS: Clinicopathological factors, hematoxylin-eosin (HE) and Masson trichome staining, immunohistochemical characteristics and the correlation between MFAP4 and TE were recorded and compared among different stages of OSF progression among cases (n = 60) and controls (n = 10). Student's t test, ANOVA analysis, and the chi-square test were performed to compare the categorical variables for clinicopathological characteristics and the expression level of MFAP4 and TE between the fibrotic and normal tissues. Correlation analysis of MFAP4 and TE was performed using Pearson's correlation test and linear regression. RESULTS: MFAP4 and TE proteins are upregulated and increased gradually in patients with varying stages of OSF, relative to the control group. Furthermore, statistical analyses revealed that the expression level of MFAP4 was positively associated with TE, with a Pearson correlation coefficient of 0.3781 (p = 0.0048). Clinically, we found that OSF affected more males than females, with a ratio of 29:1. The age range was 16-60 years, and the mean age was 36.25 ± 10.25 years. In patients younger than 40 years, the positive expression rate of MFAP4 and TE was higher than in those over 40 years. All OSF cases had chewed areca nut, with 51.67% smoking tobacco. CONCLUSIONS: Our study elucidates that the accumulation of MFAP4 and TE proteins may play a vital role in the occurrence and development of OSF and may be promising candidate moleculars for prevention, diagnosis, and treatment strategies for OSF in the future.


Assuntos
Fibrose Oral Submucosa , Tropoelastina , Adolescente , Adulto , Areca , Proteínas de Transporte , Colágeno , Proteínas da Matriz Extracelular , Feminino , Glicoproteínas , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Adulto Jovem
5.
ACS Biomater Sci Eng ; 7(11): 5028-5038, 2021 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-34676744

RESUMO

Elastin polypeptides based on -VPGVG- repeated motifs are widely used in the production of biomaterials because they are stimuli-responsive systems. On the other hand, glycine-rich sequences, mainly present in tropoelastin terminal domains, are responsible for the elastin self-assembly. In a previous study, we have recombinantly expressed a chimeric polypeptide, named resilin, elastin, and collagen (REC), inspired by glycine-rich motifs of elastin and containing resilin and collagen sequences as well. Herein, a three-block polypeptide, named (REC)3, was expressed starting from the previous monomer gene by introducing key modifications in the sequence. The choice was mandatory because the uneven distribution of the cross-linking sites in the monomer precluded the hydrogel production. In this work, the cross-linked polypeptide appeared as a soft hydrogel, as assessed by rheology, and the linear un-cross-linked trimer self-aggregated more rapidly than the REC monomer. The absence of cell-adhesive sequences did not affect cell viability, while it was functional to the production of a material presenting antiadhesive properties useful in the integration of synthetic devices in the body and preventing the invasion of cells.


Assuntos
Elastina , Hidrogéis , Colágeno , Elastina/genética , Peptídeos , Tropoelastina/genética
6.
J Med Chem ; 64(20): 15250-15261, 2021 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-34661390

RESUMO

Dysfunctional elastin turnover plays a major role in the progression of atherosclerotic plaques. Failure of tropoelastin cross-linking into mature elastin leads to the accumulation of tropoelastin within the growing plaque, increasing its instability. Here we present Gd4-TESMA, an MRI contrast agent specifically designed for molecular imaging of tropoelastin within plaques. Gd4-TESMA is a tetrameric probe composed of a tropoelastin-binding peptide (the VVGS-peptide) conjugated with four Gd(III)-DOTA-monoamide chelates. It shows a relaxivity per molecule of 34.0 ± 0.8 mM-1 s-1 (20 MHz, 298 K, pH 7.2), a good binding affinity to tropoelastin (KD = 41 ± 12 µM), and a serum half-life longer than 2 h. Gd4-TESMA accumulates specifically in atherosclerotic plaques in the ApoE-/- murine model of plaque progression, with 2 h persistence of contrast enhancement. As compared to the monomeric counterpart (Gd-TESMA), the tetrameric Gd4-TESMA probe shows a clear advantage regarding both sensitivity and imaging time window, allowing for a better characterization of atherosclerotic plaques.


Assuntos
Aterosclerose/metabolismo , Meios de Contraste/química , Elastina/metabolismo , Gadolínio/química , Imageamento por Ressonância Magnética , Tropoelastina/análise , Animais , Meios de Contraste/síntese química , Modelos Animais de Doenças , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Estrutura Molecular , Ressonância de Plasmônio de Superfície
7.
Biomolecules ; 11(9)2021 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-34572531

RESUMO

Tropoelastin, the soluble precursor of elastin, has been used for regenerative and wound healing purposes and noted for its ability to accelerate wound repair by enhancing vascularization at the site of implantation. However, it is not clear whether these effects are directly due to the interaction of tropoelastin with endothelial cells or communicated to endothelial cells following interactions between tropoelastin and neighboring cells, such as mesenchymal stem cells (MSCs). We adapted an endothelial tube formation assay to model in vivo vascularization with the goal of exploring the stimulatory mechanism of tropoelastin. In the presence of tropoelastin, endothelial cells formed less tubes, with reduced spreading into capillary-like networks. In contrast, conditioned media from MSCs that had been cultured on tropoelastin enhanced the formation of more dense, complex, and interconnected endothelial tube networks. This pro-angiogenic effect of tropoelastin is mediated indirectly through the action of tropoelastin on co-cultured cells. We conclude that tropoelastin inhibits endothelial tube formation, and that this effect is reversed by pro-angiogenic crosstalk from tropoelastin-treated MSCs. Furthermore, we find that the known in vivo pro-angiogenic effects of tropoelastin can be modeled in vitro, highlighting the value of tropoelastin as an indirect mediator of angiogenesis.


Assuntos
Células Endoteliais da Veia Umbilical Humana/metabolismo , Tropoelastina/farmacologia , Proliferação de Células/efeitos dos fármacos , Meios de Cultivo Condicionados/farmacologia , Células Endoteliais da Veia Umbilical Humana/citologia , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Neovascularização Fisiológica/efeitos dos fármacos
8.
Methods Mol Biol ; 2347: 27-33, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34472052

RESUMO

As the extracellular matrix protein, elastin is a crucial component of connective tissue in life. It is responsible for the structural integrity and function of tissues undergoing reversible extensibility or deformability, even though it may make up only a small percentage of a tissue. The structure stability, elastic resilience, bioactivity, and ability of self-assembly make elastin a highly desirable candidate for the fabrication of biomaterials. Elastin's properties mainly depend on their special structure. As elastin can be obtained by the assembly and cross-linking of its soluble precursor, tropoelastin. This chapter centers on introducing the structure of those two materials.


Assuntos
Elastina/química , Materiais Biocompatíveis , Tecido Conjuntivo , Tropoelastina
9.
Acta Biomater ; 135: 150-163, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34454082

RESUMO

Recreating the cell niche of virtually all tissues requires composite materials fabricated from multiple extracellular matrix (ECM) macromolecules. Due to their wide tissue distribution, physical attributes and purity, collagen, and more recently, tropoelastin, represent two appealing ECM components for biomaterials development. Here we blend tropoelastin and collagen, harnessing the cell-modulatory properties of each biomolecule. Tropoelastin was stably co-blended into collagen biomaterials and was retained after EDC-crosslinking. We found that human dermal fibroblasts (HDF), rat glial cells (Rugli) and HT1080 fibrosarcoma cells ligate to tropoelastin via EDTA-sensitive and EDTA-insensitive receptors or do not ligate with tropoelastin, respectively. These differing elastin-binding properties allowed us to probe the cellular response to the tropoelastin-collagen composites assigning specific bioactivity to the collagen and tropoelastin component of the composite material. Tropoelastin addition to collagen increased total Rugli cell adhesion, spreading and proliferation. This persisted with EDC-crosslinking of the tropoelastin-collagen composite. Tropoelastin addition did not affect total HDF and HT1080 cell adhesion; however, it increased the contribution of cation-independent adhesion, without affecting the cell morphology or, for HT1080 cells, proliferation. Instead, EDC-crosslinking dictated the HDF and HT1080 cellular response. These data show that a tropoelastin component dominates the response of cells that possess non-integrin based tropoelastin receptors. EDC modification of the collagen component directs cell function when non-integrin tropoelastin receptors are not crucial for cell activity. Using this approach, we have assigned the biological contribution of each component of tropoelastin-collagen composites, allowing informed biomaterial design for directed cell function via more physiologically relevant mechanisms. STATEMENT OF SIGNIFICANCE: Biomaterials fabricated from multiple extracellular matrix (ECM) macromolecules are required to fully recreate the native tissue niche where each ECM macromolecule engages with a specific repertoire of cell-surface receptors. Here we investigate combining tropoelastin with collagen as they interact with cells via different receptors. We identified specific cell lines, which associate with tropoelastin via distinct classes of cell-surface receptor. These showed that tropoelastin, when combined with collagen, altered the cell behaviour in a receptor-usage dependent manner. Integrin-mediated tropoelastin interactions influenced cell proliferation and non-integrin receptors influenced cell spreading and proliferation. These data shed light on the interplay between biomaterial macromolecular composition, cell surface receptors and cell behaviour, advancing bespoke materials design and providing functionality to specific cell populations.


Assuntos
Materiais Biocompatíveis , Tropoelastina , Animais , Adesão Celular , Colágeno , Elastina , Ratos
10.
Biophys J ; 120(20): 4623-4634, 2021 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-34339635

RESUMO

Elastin fibers assemble in the extracellular matrix from the precursor protein tropoelastin and provide the flexibility and spontaneous recoil required for arterial function. Unlike many proteins, a structure-function mechanism for elastin has been elusive. We have performed detailed NMR relaxation studies of the dynamics of the minielastins 24x' and 20x' using solution NMR, and of purified bovine elastin fibers in the presence and absence of mechanical stress using solid state NMR. The low sequence complexity of the minielastins enables us to determine average dynamical timescales and degrees of local ordering in the cross-link and hydrophobic modules separately using NMR relaxation by taking advantage of their residue-specific resolution. We find an extremely high degree of disorder, with order parameters for the entirety of the hydrophobic domains near zero, resembling that of simple chemical polymers and less than the order parameters that have been observed in other intrinsically disordered proteins. We find that average backbone order parameters in natural, purified elastin fibers are comparable to those found in 24x' and 20x' in solution. The difference in dynamics, compared with the minielastins, is that backbone correlation times are significantly slowed in purified elastin. Moreover, when elastin is mechanically stretched, the high chain disorder in purified elastin is retained, showing that any change in local ordering is below that detectable in our experiment. Combined with our previous finding of a 10-fold increase in the ordering of water when fully hydrated elastin fibers are stretched by 50%, these results support the hypothesis that stretch induced solvent ordering, i.e., the hydrophobic effect, is a key player in the elastic recoil of elastin as opposed to configurational entropy loss.


Assuntos
Tecido Elástico , Elastina , Animais , Bovinos , Matriz Extracelular , Interações Hidrofóbicas e Hidrofílicas , Tropoelastina
11.
Biophys J ; 120(15): 3138-3151, 2021 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-34197806

RESUMO

Tropoelastin is the highly flexible monomer subunit of elastin, required for the resilience of the extracellular matrix in elastic tissues. To elicit biological signaling, multiple sites on tropoelastin bind to cell surface integrins in a poorly understood multifactorial process. We constructed a full atomistic molecular model of the interactions between tropoelastin and integrin αvß3 using ensemble-based computational methodologies. Conformational changes of integrin αvß3 associated with outside-in signaling were more frequently facilitated in an ensemble in which tropoelastin bound the integrin's α1 helix rather than the upstream canonical binding site. Our findings support a model of fuzzy binding, whereby many tropoelastin conformations and defined sites cooperatively interact with multiple αvß3 regions. This model explains prior experimental binding to distinct tropoelastin regions, domains 17 and 36, and points to the cooperative participation of domain 20. Our study highlights the utility of ensemble-based approaches in helping to understand the interactive mechanisms of functionally significant flexible proteins.


Assuntos
Integrina alfaVbeta3 , Tropoelastina , Sítios de Ligação , Elastina , Matriz Extracelular , Humanos
12.
Acta Biomater ; 134: 477-489, 2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34303013

RESUMO

We propose a simple general framework to predict folding, native states, energy barriers, protein unfolding, as well as mutation induced diseases and other protein structural analyses. The model should not be considered as an alternative to classical approaches (Molecular Dynamics or Monte Carlo) because it neglects low scale details and rather focuses on global features of proteins and structural information. We aim at the description of phenomena that are out of the range of classical molecular modeling approaches due to the large computational cost: multimolecular interactions, cyclic behavior under variable external interactions, and similar. To demonstrate the effectiveness of the approach in a real case, we focus on the folding and unfolding behavior of tropoelastin and its mutations. Specifically, we derive a discrete mechanical model whose structure is deduced based on a coarse graining approach that allows us to group the amino acids sequence in a smaller number of `equivalent' masses. Nearest neighbor energy terms are then introduced to reproduce the interaction of such amino acid groups. Nearest and non-nearest neighbor energy terms, inter and intra functional blocks are phenomenologically added in the form of Morse potentials. As we show, the resulting system reproduces important properties of the folding-unfolding mechanical response, including the monotonic and cyclic force-elongation behavior, representing a physiologically important information for elastin. The comparison with the experimental behavior of mutated tropoelastin confirms the predictivity of the model. STATEMENT OF SIGNIFICANCE: Classical approaches to the study of phenomena at the molecular scale such as Molecular Dynamics (MD) represent an incredible tool to unveil mechanical and conformational properties of macromolecules, in particular for biological and medical applications. On the other hand, due to the computational cost, the time and spatial scales are limited. Focusing of the real case of tropoelastin, we propose a new approach based on a careful coarse graining of the system, able to describe the overall properties of the macromolecule and amenable of extension to larger scale effects (protein bundles, protein-protein interactions, cyclic loading). The comparison with tropoelastin behavior, also for mutations, is very promising.


Assuntos
Simulação de Dinâmica Molecular , Tropoelastina , Elastina , Método de Monte Carlo , Mutação/genética , Tropoelastina/genética
13.
Mol Med Rep ; 24(2)2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34080027

RESUMO

Chronic venous disease (CVD) is the response to a series of hemodynamic changes in the venous system and the onset of this disease is often triggered by pregnancy. Placental tissue is particularly sensitive to the characteristic changes which occurs in venous hypertension. In this regard, changes in the extracellular matrix (ECM), that occur to adapt to this situation, are fundamental to controlling elastogenesis. Therefore, the aim of the present study was to analyze the changes that occur in the mRNA and protein expression level of proteins related to elastogenesis in the placental villi of women diagnosed with CVD, in the third trimester of pregnancy. An observational, analytical and prospective cohort study was conducted, in which the placenta from 62 women with CVD were compared with that in placenta from 52 women without a diagnosis of CVD. Gene and protein expression levels were analyzed using reverse transcription­quantitative PCR and immunohistochemistry, respectively. The results showed a significant decrease in the gene and protein expression level of EGFL7 in the placental villi of women with CVD. By contrast, significant increases in the gene and protein expression level of ECM­related proteins, such as tropoelastin, fibulin 4, fibrillin 1 and members of the lysyl oxidase family (LOX and LOXL­1) were also found in the placental villi of women with CVD. To the best of our knowledge, the results from the present study showed for the first time that CVD during pregnancy was associated with changes in the mRNA and protein expression level in essential components of the EGFL7­modulated elastogenesis process in placental villi.


Assuntos
Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Vilosidades Coriônicas/metabolismo , Família de Proteínas EGF/genética , Família de Proteínas EGF/metabolismo , Placenta/metabolismo , Complicações Cardiovasculares na Gravidez/genética , Complicações Cardiovasculares na Gravidez/metabolismo , Doenças Vasculares/metabolismo , Adulto , Aminoácido Oxirredutases/genética , Aminoácido Oxirredutases/metabolismo , Vilosidades Coriônicas/patologia , Doença Crônica , Estudos de Coortes , Tecido Elástico/metabolismo , Proteínas da Matriz Extracelular/genética , Proteínas da Matriz Extracelular/metabolismo , Feminino , Fibrilina-1/genética , Fibrilina-1/metabolismo , Humanos , Placenta/patologia , Gravidez , Estudos Prospectivos , Proteína-Lisina 6-Oxidase/genética , Proteína-Lisina 6-Oxidase/metabolismo , Tropoelastina/genética , Tropoelastina/metabolismo , Adulto Jovem
14.
Zhong Nan Da Xue Xue Bao Yi Xue Ban ; 46(5): 458-466, 2021 May 28.
Artigo em Inglês, Chinês | MEDLINE | ID: mdl-34148881

RESUMO

OBJECTIVES: To evaluate the relation between single nucleotide polymorphisms (SNPs) of tropoelastin gene and aortic dissection (AD) via identifying SNPs in the tropoelastin gene, and to detect the level of tropoelastin mRNA, elastin and elastic fibers. METHODS: The specimens of the AD group (n=96) and the control group (n=95), including their blood and aortic wall tissues, were collected. DNA was extracted from the blood samples in the 2 groups, and the SNPs in the tropoelastin gene were examined by the MassARRAY genotyping technique, and their haplotypes were constructed by PHASE software. The expression of tropoelastin mRNA and elastin in the aortic tunica media was respectively detected by real-time PCR or Western blotting. Elastin Van Gieson (EVG) staining was used to observe the shape of aortic tunica media and clarify the distribution of elastic fibers. The frequency of genotypes and haplotypes of SNP loci in the tropoelastin gene was analyzed and compared between the 2 groups, and the expression of tropoelastin mRNA, elastin and elastic fibers were also compared. RESULTS: Seven SNP loci of the tropoelastin gene were detected in these samples. Among them, 5 SNP loci were polymorphic. The frequency of 3 SNP loci[rs2071307 (G/A), rs34945509 (C/T) and rs17855988 (G/C)] was significantly different between the AD group and the control group (all P<0.05). There were significantly different in the haplotypes frequency of rs2071307 (G/A), rs34945509 (C/T) and rs17855988 (G/C) between the 2 groups (all P<0.01). Real-time PCR and Western blotting showed that the relative expression of tropoelastin mRNA and elastin in the aortic tunica media in the AD group was significantly lower than that in the control group (P<0.05). EVG staining showed that the aortic tunica media was torn, the morphology and structure of elastic fibers were broken, cracked, and disordered in the AD group, while the aortic tunica media was in complete structure and well arrangement.The elastic fibers were presented closely and orderly in the control group. CONCLUSIONS: The polymorphisms of rs2071307 (G/A), rs34945509 (C/T), and rs17855988(G/C) in the tropoelastin gene may eventually affect the synthesis of elastic fibers and they may play an important role in the occurrence of AD.


Assuntos
Aneurisma Dissecante , Tropoelastina , Aneurisma Dissecante/genética , Tecido Elástico , Elastina/genética , Humanos , Polimorfismo de Nucleotídeo Único , Tropoelastina/genética
15.
Mol Biol Rep ; 48(5): 4865-4878, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-34129188

RESUMO

Elastic fibers are essential components of the arterial extracellular matrix. They consist of the protein elastin and an array of microfibrils that support the protein and connect it to the surrounding matrix. The elastin gene encodes tropoelastin, a protein that requires extensive cross-linking to become elastin. Tropoelastin is expressed throughout human life, but its expression levels decrease with age, suggesting that the potential to synthesize elastin persists during lifetime although declines with aging. The initial abnormality documented in human atherosclerosis is fragmentation and loss of the elastic network in the medial layer of the arterial wall, suggesting an imbalance between elastic fiber injury and restoration. Damaged elastic structures are not adequately repaired by synthesis of new elastic elements. Progressive collagen accumulation follows medial elastic fiber disruption and fibrous plaques are formed, but advanced atherosclerosis lesions do not develop in the absence of prior elastic injury. Aging is associated with arterial extracellular matrix anomalies that evoke those present in early atherosclerosis. The reduction of elastic fibers with subsequent collagen accumulation leads to arterial stiffening and intima-media thickening, which are independent predictors of incident hypertension in prospective community-based studies. Arterial stiffening precedes the development of hypertension. The fundamental role of the vascular elastic network to arterial structure and function is emphasized by congenital disorders caused by mutations that disrupt normal elastic fiber production. Molecular changes in the genes coding tropoelastin, lysyl oxidase (tropoelastin cross-linking), and elastin-associated microfibrils, including fibrillin-1, fibulin-4, and fibulin-5 produce severe vascular injury due to absence of functional elastin.


Assuntos
Tecido Elástico/patologia , Doenças Vasculares , Envelhecimento/fisiologia , Animais , Aterosclerose/patologia , Colágeno/metabolismo , Anormalidades Congênitas , Tecido Elástico/citologia , Tecido Elástico/metabolismo , Elastina/metabolismo , Matriz Extracelular/metabolismo , Matriz Extracelular/patologia , Fibrilinas/genética , Fibrilinas/metabolismo , Fibroblastos/metabolismo , Humanos , Proteínas dos Microfilamentos/metabolismo , Mutação , Proteína-Lisina 6-Oxidase/genética , Proteína-Lisina 6-Oxidase/metabolismo , Tropoelastina/genética , Tropoelastina/metabolismo , Doenças Vasculares/metabolismo , Doenças Vasculares/patologia , Rigidez Vascular/fisiologia
16.
Sci Rep ; 11(1): 11004, 2021 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-34040032

RESUMO

The aim of this study was to investigate the merits of magnetic resonance imaging (MRI) using an elastin-binding contrast agent after myocardial infarction in mouse models with deletions of monocyte populations. Permanent ligation of the left anterior descending (LAD) artery was conducted in 10 wild-type mice and 10 each of three knockout models: CX3CR-/-, CCR2-/-, and MCP-1-/-. At 7 days and 30 days after permanent ligation, cardiac MRI was performed with a 7 T-Bruker horizontal scanner for in vivo detection of elastin with an elastin/tropoelastin-specific contrast agent (ESMA). Histology was performed with staining for elastin, collagen I and III, and F4/80. Real-time PCR was conducted to quantify the expression of genes for collagen I and III, F4/80, and tumor necrosis factor alpha (TNFα). Histological and ESMA-indicated elastin areas were strongly correlated (r = 0.8). 30 days after permanent ligation, CCR2-deficient mice demonstrated higher elastin levels in the scar relative to MCP-1-/- (p < 0.04) and wild-type mice (p < 0.02). The ejection fraction was lower in CCR2-deficient mice. In vivo MRI in mouse models of MI can detect elastin deposition after myocardial infarction, highlighting the pivotal role of elastin in myocardial remodeling in mouse models with deletions of monocyte populations.


Assuntos
Elastina , Imageamento por Ressonância Magnética , Infarto do Miocárdio , Animais , Cicatriz/patologia , Vasos Coronários/patologia , Camundongos , Tropoelastina/metabolismo , Remodelação Ventricular
17.
Mater Sci Eng C Mater Biol Appl ; 120: 111788, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33545914

RESUMO

Elastic fibres play a key role in bodily functions where fatigue resistance and elastic recovery are necessary while regulating phenotype, proliferation and migration in cells. While in vivo elastic fibres are created at a late foetal stage, a major obstacle in the development of engineered tissue is that human vascular smooth muscle cells (hVSMCs), one of the principal elastogenic cells, are unable to spontaneously promote elastogenesis in vitro. Therefore, the overall aim of this study was to activate elastogenesis in vitro by hVSMCs seeded in fibrin, collagen, glycosaminoglycan (FCG) scaffolds, following the addition of recombinant human tropoelastin. This combination of scaffold, tropoelastin and cells induced the deposition of elastin and formation of lamellar maturing elastic fibres, similar to those found in skin, blood vessels and heart valves. Furthermore, higher numbers of maturing branched elastic fibres were synthesised when a higher cell density was used and by drop-loading tropoelastin onto cell-seeded FCG scaffolds prior to adding growth medium. The addition of tropoelastin showed no effect on cell proliferation or mechanical properties of the scaffold which remained dimensionally stable throughout. With these results, we have established a natural biomaterial scaffold that can undergo controlled elastogenesis on demand, suitable for tissue engineering applications.


Assuntos
Materiais Biocompatíveis , Tecido Elástico , Materiais Biocompatíveis/farmacologia , Elastina , Humanos , Engenharia Tecidual , Tropoelastina
18.
FEBS J ; 288(13): 4024-4038, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33404190

RESUMO

Elastin is an extracellular matrix component with key structural and biological roles in elastic tissues. Interactions between resident cells and tropoelastin, the monomer of elastin, underpin elastin's regulation of cellular processes. However, the nature of tropoelastin-cell interactions and the contributions of individual tropoelastin domains to these interactions are only partly elucidated. In this study, we identified and characterized novel cell-adhesive sites in the tropoelastin N-terminal region between domains 12 and 16. We found that this region interacts with αV and α5ß1 integrin receptors, which mediate cell attachment and spreading. A peptide sequence from within this region, spanning domains 14 to mid-domain 16, binds heparan sulfate through electrostatic interactions with peptide lysine residues and induces conformational ordering of the peptide. We propose that domains 14-16 direct initial cell attachment through cell-surface heparan sulfate glycosaminoglycans, followed by αV and α5ß1 integrin-promoted attachment and spreading on domains 12-16 of tropoelastin. These findings advance our mechanistic understanding of elastin matrix biology, with the potential to enhance tissue regenerative outcomes of elastin-based materials.


Assuntos
Glicosaminoglicanos/metabolismo , Integrina alfa5beta1/metabolismo , Integrina alfaV/metabolismo , Tropoelastina/metabolismo , Sequência de Aminoácidos , Sítios de Ligação/genética , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Movimento Celular/efeitos dos fármacos , Dicroísmo Circular , Humanos , Peptídeos/química , Peptídeos/genética , Peptídeos/farmacologia , Ligação Proteica/efeitos dos fármacos , Conformação Proteica , Domínios Proteicos , Tropoelastina/química , Tropoelastina/genética
19.
Biopolymers ; 112(2): e23414, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33351193

RESUMO

Elastin is a major polymeric protein of the extracellular matrix, providing critical properties of extensibility and elastic recoil. The rs2071307 genomic polymorphism, resulting in the substitution of a serine for a glycine residue in a VPG motif in tropoelastin, has an unusually high minor allele frequency in humans. A consequence of such allelic heterozygosity would be the presence of a heterogeneous elastin polymer in up to 50% of the population, a situation which appears to be unique to Homo sapiens. VPG motifs are extremely common in hydrophobic domains of tropoelastins and are the sites of transient ß-turns that are essential for maintaining the conformational flexibility required for its function as an entropic elastomer. Earlier data demonstrated that single amino acid substitutions in tropoelastin can have functional consequences for polymeric elastin, particularly when present in mixed polymers. Here, using NMR and molecular dynamics approaches, we show the rs2071307 polymorphism reduces local propensity for ß-turn formation, with a consequent increase in polypeptide hydration and an expansion of the conformational ensemble manifested as an increased hydrodynamic radius, radius of gyration and asphericity. Furthermore, this substitution affects functional properties of polymeric elastin, particularly in heterogeneous polymers mimicking allelic heterozygosity. We discuss whether such effects, together with the unusually high minor allele frequency of the polymorphism, could imply some some evolutionary advantage for the heterozygous state.


Assuntos
Polimorfismo de Nucleotídeo Único , Tropoelastina/química , Tropoelastina/genética , Animais , Evolução Molecular , Frequência do Gene , Humanos , Interações Hidrofóbicas e Hidrofílicas , Simulação de Dinâmica Molecular , Homem de Neandertal/genética , Ressonância Magnética Nuclear Biomolecular , Tropoelastina/metabolismo
20.
J Drugs Dermatol ; 19(12): 1166-1172, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33346526

RESUMO

BACKGROUND: Elastin is an essential component of the dermis, providing skin with elasticity and integrity. Elastin and other dermal components are gradually lost through aging, sun damage, and following injury, highlighting a need to replace these components to repair the skin. Tropoelastin (TE) in monomeric form was previously shown to be utilized as a substrate by dermal fibroblasts during the production of elastin fibers in vitro. OBJECTIVE: To analyze coaccumulation of elastin and collagen and gene expression of biomarkers associated with elastin production, examine the ex vivo effects of recombinant human TE (rhTE) and hyaluronic acid (HA) on epidermal and dermal structures, and evaluate the in vivo response following intradermal injections of rhTE and HA. METHODS: Human dermal fibroblasts and 3-D skin patch models were cultured for in vitro analysis. Ex vivo analysis was performed using skin explants. In vivo studies were done in 6-week-old male CD Hairless rats. Different formulations of rhTE, soluble or crosslinked using derivatized HA (dHA), were tested and analyzed. RESULTS: rhTE in monomeric form was utilized as a substrate by dermal fibroblasts during the production of branched elastin and fibrous collagen networks in vitro. Formulations of rhTE crosslinked with dHA demonstrated increased expression of hyaluronic acid synthase 1 and ex vivo results revealed increased moisture content and glycosaminoglycan (GAG) deposition versus dermal filler control. Intradermal rhTE‒dHA injection produced colocalized human‒rat elastin fibers in vivo. CONCLUSIONS: These results suggest that the novel rhTE‒dHA matrix is an attractive material to support skin tissue repair.J Drugs Dermatol. 2020;19(12): doi:10.36849/JDD.2020.5375.


Assuntos
Preenchedores Dérmicos/administração & dosagem , Matriz Extracelular/efeitos dos fármacos , Envelhecimento da Pele/efeitos dos fármacos , Pele/efeitos dos fármacos , Tropoelastina/administração & dosagem , Animais , Linhagem Celular , Colágeno/análise , Colágeno/metabolismo , Técnicas Cosméticas , Implantes de Medicamento , Elastina/análise , Elastina/metabolismo , Matriz Extracelular/metabolismo , Feminino , Fibroblastos , Glicosaminoglicanos/análise , Glicosaminoglicanos/metabolismo , Humanos , Ácido Hialurônico/administração & dosagem , Injeções Intradérmicas , Masculino , Pessoa de Meia-Idade , Modelos Animais , Ratos , Proteínas Recombinantes/administração & dosagem , Pele/química , Pele/citologia , Pele/metabolismo , Técnicas de Cultura de Tecidos
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