scholarly journals The role of caveolin-1 in pulmonary matrix remodeling and mechanical properties

2008 ◽  
Vol 295 (6) ◽  
pp. L1007-L1017 ◽  
Author(s):  
O. Le Saux ◽  
K. Teeters ◽  
S. Miyasato ◽  
J. Choi ◽  
G. Nakamatsu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Signal Transduction ◽  
Airway Resistance ◽  
Transforming Growth Factor ◽  
Interstitial Fibrosis ◽  
Elastic Fiber ◽  
Elastic Fibers ◽  
Matrix Remodeling ◽  
Caveolin 1 ◽  
Fiber Deposition

Caveolin-1 (cav1) is a 22-kDa membrane protein essential to the formation of small invaginations in the plasma membrane, called caveolae. The cav1 gene is expressed primarily in adherent cells such as endothelial and smooth muscle cells and fibroblasts. Caveolae contain a variety of signaling receptors, and cav1 notably downregulates transforming growth factor (TGF)-β signal transduction. In pulmonary pathologies such as interstitial fibrosis or emphysema, altered mechanical properties of the lungs are often associated with abnormal ECM deposition. In this study, we examined the physiological functions and the deposition of ECM in cav1−/− mice at various ages (1–12 mo). Cav1−/− mice lack caveolae and by 3 mo of age have significant reduced lung compliance and increased elastance and airway resistance. Pulmonary extravasation of fluid, as part of the cav1−/− mouse phenotype, probably contributed to the alteration of compliance, which was compounded by a progressive increase in deposition of collagen fibrils in airways and parenchyma. We also found that the increased elastance was caused by abundant elastic fiber deposition primarily around airways in cav1−/− mice at least 3 mo old. These observed changes in the ECM composition probably also contribute to the increased airway resistance. The higher deposition of collagen and elastic fibers was associated with increased tropoelastin and col1α2 and col3α1 gene expression in lung tissues, which correlated tightly with increased TGF-β/Smad signal transduction. Our study illustrates that perturbation of cav1 function may contribute to several pulmonary pathologies as the result of the important role played by cav1, as part of the TGF-β signaling pathway, in the regulation of the pulmonary ECM.

Postnatal alterations in elastic fiber organization precede resistance artery narrowing in SHR

2006 ◽  
Vol 291 (2) ◽  
pp. H804-H812 ◽  
Author(s):  
José M. González ◽  
Ana M. Briones ◽  
Beatriz Somoza ◽  
Craig J. Daly ◽  
Elisabet Vila ◽  
...  
Keyword(s):  
Time Course ◽  
Elastic Fiber ◽  
Elastic Fibers ◽  
Early Event ◽  
Resistance Artery ◽  
Internal Elastic Lamina ◽  
Wall Stiffness ◽  
Fiber Deposition ◽  
Fiber Organization ◽  
Elastic Lamina

Resistance artery narrowing and stiffening are key elements in the pathogenesis of essential hypertension, but their origin is not completely understood. In mesenteric resistance arteries (MRA) from spontaneously hypertensive rats (SHR), we have shown that inward remodeling is associated with abnormal elastic fiber organization, leading to smaller fenestrae in the internal elastic lamina. Our current aim is to determine whether this alteration is an early event that precedes vessel narrowing, or if elastic fiber reorganization in SHR arteries occurs because of the remodeling process itself. Using MRA from 10-day-old, 30-day-old, and 6-mo-old SHR and normotensive Wistar Kyoto rats, we investigated the time course of the development of structural and mechanical alterations (pressure myography), elastic fiber organization (confocal microscopy), and amount of elastin (radioimmunoassay for desmosine) and collagen (picrosirius red). SHR MRA had an impairment of fenestrae enlargement during the first month of life. In 30-day-old SHR, smaller fenestrae and more packed elastic fibers in the internal elastic lamina were paralleled by increased wall stiffness. Collagen and elastin levels were unaltered at this age. MRA from 6-mo-old SHR also had smaller fenestrae and a denser network of adventitial elastic fibers, accompanied by increased collagen content and vessel narrowing. At this age, elastase digestion was less effective in SHR MRA, suggesting a lower susceptibility of elastic fibers to enzymatic degradation. These data suggest that abnormal elastic fiber deposition in SHR increases resistance artery stiffness at an early age, which might participate in vessel narrowing later in life.

scholarly journals Functionally Distinct Tendons From Elastin Haploinsufficient Mice Exhibit Mild Stiffening and Tendon-Specific Structural Alteration

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
Jeremy D. Eekhoff ◽  
Fei Fang ◽  
Lindsey G. Kahan ◽  
Gabriela Espinosa ◽  
Austin J. Cocciolone ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Fiber ◽  
Mechanical Effect ◽  
Elastic Fibers ◽  
Minor Role ◽  
Tendon Mechanics ◽  
Different Types ◽  
A Minor ◽  
Collagen Alignment

Elastic fibers are present in low quantities in tendon, where they are located both within fascicles near tenocytes and more broadly in the interfascicular matrix (IFM). While elastic fibers have long been known to be significant in the mechanics of elastin-rich tissue (i.e., vasculature, skin, lungs), recent studies have suggested a mechanical role for elastic fibers in tendons that is dependent on specific tendon function. However, the exact contribution of elastin to properties of different types of tendons (e.g., positional, energy-storing) remains unknown. Therefore, this study purposed to evaluate the role of elastin in the mechanical properties and collagen alignment of functionally distinct supraspinatus tendons (SSTs) and Achilles tendons (ATs) from elastin haploinsufficient (HET) and wild type (WT) mice. Despite the significant decrease in elastin in HET tendons, a slight increase in linear stiffness of both tendons was the only significant mechanical effect of elastin haploinsufficiency. Additionally, there were significant changes in collagen nanostructure and subtle alteration to collagen alignment in the AT but not the SST. Hence, elastin may play only a minor role in tendon mechanical properties. Alternatively, larger changes to tendon mechanics may have been mitigated by developmental compensation of HET tendons and/or the role of elastic fibers may be less prominent in smaller mouse tendons compared to the larger bovine and human tendons evaluated in previous studies. Further research will be necessary to fully elucidate the influence of various elastic fiber components on structure–function relationships in functionally distinct tendons.

scholarly journals Critical analysis of aortic dysmorphism in Marfan Syndrome

2017 ◽  
Vol 34 (01) ◽  
pp. 001-006
Author(s):  
R. Souza ◽  
L. Cassiano ◽  
A. Liberatore ◽  
R. Tedesco ◽  
I. Koh ◽  
...  
Keyword(s):  
Marfan Syndrome ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Elastic System ◽  
Experimental Studies ◽  
Smooth Muscles ◽  
Elastic Fibers ◽  
Matrix Remodeling ◽  
Structural Protein ◽  
Fibrillin 1

Abstract Introduction: Marfan syndrome (OMIM #154700) was described for the first time in 1896 by Antoine Bernard-Jean Marfan. It is characterized by its autosomal dominant inheritance pattern, affects 1:5000 of those born alive, and involves the gene that codifies the structural protein fribrillin-1. Fibrillin-1 is critical for the formation of the elastic system backbone and for the negative regulation of the cytokine transforming growth factor beta 1 (TGF-β1). In the syndrome this fibrillar component causes the degeneration of the fibers of the elastic system, which no longer sequesters matrix TGF-β, causing disorganization of the collagen fibers and vascular smooth muscles. The disease affects mainly the cardiovascular system, cardiovascular problems being the main cause of death. This is because arteries have large amounts of elastic fibers that rupture in an adverse process, causing mainly dissections and aneurisms, which have been better clariied in experimental studies with mice. Objective: The objective of this study was to conduct an etiopathogenic and molecular review to describe the advances in the understanding of blood vessel dysmorphism in the syndrome, especially of the aorta. Materials and Methods: For this purpose the literature of the last 35 years was extensively reviewed. Conclusion: The origin of the aortic dysmorphism in the syndrome stems from a number of events that begin with the mutation of the gene fibrillin-1, causing fragmentation of the aortic elastic fibers. Excess cytokine TGF-β increases the amount of metalloproteinases and of vascular smooth muscle cell apoptosis, leading to matrix remodeling and increasing the susceptibility of the vessel to an aneurysm or dissecting process.

scholarly journals IUGR decreases elastin mRNA expression in the developing rat lung and alters elastin content and lung compliance in the mature rat lung

2011 ◽  
Vol 43 (9) ◽  
pp. 499-505 ◽  
Author(s):  
Lisa A. Joss-Moore ◽  
Yan Wang ◽  
Xing Yu ◽  
Michael S. Campbell ◽  
Christopher W. Callaway ◽  
...  
Keyword(s):  
Elastic Fiber ◽  
Lung Compliance ◽  
Fiber Formation ◽  
Elastic Fibers ◽  
Mrna Levels ◽  
Rat Lung ◽  
Mrna Transcript ◽  
Transcript Levels ◽  
Alveolar Development ◽  
Fiber Deposition

Complications of intrauterine growth restriction (IUGR) include increased pulmonary morbidities and impaired alveolar development. Normal alveolar development depends upon elastin expression and processing, as well as the formation and deposition of elastic fibers. This is true of the human and rat. In this study, we hypothesized that uteroplacental insufficiency (UPI)-induced IUGR decreases mRNA levels of elastin and genes required for elastin fiber synthesis and assembly, at birth (prealveolarization) and postnatal day 7 (midalveolarization) in the rat. We further hypothesized that this would be accompanied by reduced elastic fiber deposition and increased static compliance at postnatal day 21 (mature lung). We used a well characterized rat model of IUGR to test these hypotheses. IUGR decreases mRNA transcript levels of genes essential for elastic fiber formation, including elastin, at birth and day 7. In the day 21 lung, IUGR decreases elastic fiber deposition and increases static lung compliance. We conclude that IUGR decreases mRNA transcript levels of elastic fiber synthesis genes, before and during alveolarization leading to a reduced elastic fiber density and increased static lung compliance in the mature lung. We speculate that the mechanism by which IUGR predisposes to pulmonary disease may be via decreased lung elastic fiber deposition.

scholarly journals Role of LTBP4 in alveolarization, angiogenesis, and fibrosis in lungs

2017 ◽  
Vol 313 (4) ◽  
pp. L687-L698 ◽  
Author(s):  
Insa Bultmann-Mellin ◽  
Katharina Dinger ◽  
Carolin Debuschewitz ◽  
Katharina M. A. Loewe ◽  
Yvonne Melcher ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Matrix Protein ◽  
Transforming Growth Factor ◽  
Elastic Fiber ◽  
Transforming Growth Factor Β ◽  
Matrix Proteins ◽  
Extracellular Matrix Protein ◽  
Elastic Fibers ◽  
Fiber Network

Deficiency of the extracellular matrix protein latent transforming growth factor-β (TGF-β)-binding protein-4 (LTBP4) results in lack of intact elastic fibers, which leads to disturbed pulmonary development and lack of normal alveolarization in humans and mice. Formation of alveoli and alveolar septation in pulmonary development requires the concerted interaction of extracellular matrix proteins, growth factors such as TGF-β, fibroblasts, and myofibroblasts to promote elastogenesis as well as vascular formation in the alveolar septae. To investigate the role of LTBP4 in this context, lungs of LTBP4-deficient ( Ltbp4−/−) mice were analyzed in close detail. We elucidate the role of LTBP4 in pulmonary alveolarization and show that three different, interacting mechanisms might contribute to alveolar septation defects in Ltbp4−/− lungs: 1) absence of an intact elastic fiber network, 2) reduced angiogenesis, and 3) upregulation of TGF-β activity resulting in profibrotic processes in the lung.

scholarly journals Nanoindentation of histological specimens: Mapping the elastic properties of soft tissues

2009 ◽  
Vol 24 (3) ◽  
pp. 638-646 ◽  
Author(s):  
R. Akhtar ◽  
N. Schwarzer ◽  
M.J. Sherratt ◽  
R.E.B. Watson ◽  
H.K. Graham ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Extracellular Matrix ◽  
Elastic Modulus ◽  
Soft Tissues ◽  
Elastic Fiber ◽  
Vena Cava ◽  
Elastic Fibers ◽  
Fiber Density ◽  
Tissue Microstructure ◽  
Micromechanical Properties

Although alterations in the gross mechanical properties of dynamic and compliant tissues have a major impact on human health and morbidity, there are no well-established techniques to characterize the micromechanical properties of tissues such as blood vessels and lungs. We have used nanoindentation to spatially map the micromechanical properties of 5-μm-thick sections of ferret aorta and vena cava and to relate these mechanical properties to the histological distribution of fluorescent elastic fibers. To decouple the effect of the glass substrate on our analysis of the nanoindentation data, we have used the extended Oliver and Pharr method. The elastic modulus of the aorta decreased progressively from 35 MPa in the adventitial (outermost) layer to 8 MPa at the intimal (innermost) layer. In contrast, the vena cava was relatively stiff, with an elastic modulus >30 MPa in both the extracellular matrix-rich adventitial and intimal regions of the vessel. The central, highly cellularized, medial layer of the vena cava, however, had an invariant elastic modulus of ∼20 MPa. In extracellular matrix-rich regions of the tissue, the elastic modulus, as determined by nanoindentation, was inversely correlated with elastic fiber density. Thus, we show it is possible to distinguish and spatially resolve differences in the micromechanical properties of large arteries and veins, which are related to the tissue microstructure.

scholarly journals Dendrobium Mixture Improved Diabetic Nephropathy in db/db Mice by Regulating TGF-β1/Smads Signal Transduction

2021 ◽  
Author(s):  
Yong Chen ◽  
Xiaohui Lin ◽  
Yanfang Zheng ◽  
Wenzhen Yu ◽  
Fan Lin ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Diabetic Nephropathy ◽  
Mrna Expression ◽  
Signaling Pathway ◽  
Transforming Growth Factor ◽  
Interstitial Fibrosis ◽  
Fasting Blood Glucose ◽  
Blood Lipid ◽  
Control Group ◽  
Tgf Β1

Abstract BackgroundDendrobium mixture (DMix) is an effective treatment for diabetic nephropathy (DN), but the underlying molecular mechanism remains unclear. In this study, we investigated whether DMix regulates the transforming growth factor-β1 (TGF-β1)/Smads signal transduction pathway. MethodsTwenty-four db/db mice were randomly divided into three groups: the model, DMix, and gliquidone groups, while eight db/m mice were selected as the normal control group. The drug was administered by continuous gavage for 8 weeks. Body weight (BW), kidney weight (KW), kidney index, fasting blood glucose (FBG), blood lipid, 24-hour urinary albumin excretion rate, blood urea nitrogen, and serum creatinine levels were measured. Pathological changes in the renal tissue were observed using a light microscope. Real-time quantitative PCR and immunohistochemical staining were used to detect mRNA expression of TGF-β1 and alpha-smooth muscle actin (α-SMA) genes and proteins, respectively, in renal tissues. TGF-β1, Smad2, p-Smad2, Smad3, p-Smad3, and α-SMA expression levels were measured using western blotting. ResultsDMix significantly reduced FBG level, BW, KW, and blood lipid level, and improved renal function in db/db mice. Histopathology showed that DMix alleviated glomerular mesangial cell proliferation and renal interstitial fibrosis in db/db mice. Additionally, DMix reduced protein and mRNA expression of TGF-β1 and α-SMA, and inhibited Smad2 and Smad3 phosphorylation. ConclusionsThe findings suggest that DMix may inhibit renal fibrosis and delay the progression of DN by regulating the TGF-β1/Smads signaling pathway. Key words: Diabetic nephropathy, Dendrobium mixture, TGF-β1/Smads signaling pathway

scholarly journals Strain-dependent effects on lung structure, matrix remodeling, and Stat3/Smad2 signaling in C57BL/6N and C57BL/6J mice after neonatal hyperoxia

2019 ◽  
Vol 317 (1) ◽  
pp. R169-R181 ◽  
Author(s):  
Johannes P. Will ◽  
Dharmesh Hirani ◽  
Florian Thielen ◽  
Fabian Klein ◽  
Christina Vohlen ◽  
...  
Keyword(s):  
Animal Models ◽  
Lung Injury ◽  
Genetic Susceptibility ◽  
Transforming Growth Factor ◽  
Elastic Fiber ◽  
Matrix Remodeling ◽  
Lung Weight ◽  
Newborn Mice ◽  
Lung Structure ◽  
Strain Dependent

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of preterm infants, characterized by lung growth arrest and matrix remodeling. Various animal models provide mechanistic insights in the pathogenesis of BPD. Since there is increasing evidence that genetic susceptibility modifies the response to lung injury, we investigated strain-dependent effects in hyperoxia (HYX)-induced lung injury of newborn mice. To this end, we exposed newborn C57BL/6N and C57BL/6J mice to 85% O2 (HYX) or normoxia (NOX; 21% O2) for 28 days, followed by lung excision for histological and molecular measurements. BL/6J-NOX mice exhibited a lower body and lung weight than BL/6N-NOX mice; hyperoxia reduced body weight in both strains and increased lung weight only in BL/6J-HYX mice. Quantitative histomorphometric analyses revealed reduced alveolar formation in lungs of both strains after HYX, but the effect was greater in BL/6J-HYX mice than BL/6N-HYX mice. Septal thickness was lower in BL/6J-NOX mice than BL/6N-NOX mice but increased in both strains after HYX. Elastic fiber density was significantly greater in BL/6J-HYX mice than BL/6N-HYX mice. Lungs of BL/6J-HYX mice were protected from changes in gene expression of fibrillin-1, fibrillin-2, fibulin-4, fibulin-5, and surfactant proteins seen in BL/6N-HYX mice. Finally, Stat3 was activated by HYX in both strains; in contrast, activation of Smad2 was markedly greater in lungs of BL/6N mice than BL/6J mice after HYX. In summary, we demonstrate strain-dependent differences in lung structure and matrix, alveolar epithelial cell markers, and Smad2 (transforming growth factor β) signaling in neonatal HYX-induced lung injury. Strain-dependent effects and genetic susceptibility need be taken into consideration for reproducibility and reliability of results in animal models.

Lung tissue mechanics and extracellular matrix composition in a murine model of silicosis

2001 ◽  
Vol 90 (4) ◽  
pp. 1400-1406 ◽  
Author(s):  
Débora S. Faffe ◽  
Gabriela H. Silva ◽  
Pedro M. P. Kurtz ◽  
Elnara M. Negri ◽  
Vera L. Capelozzi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Extracellular Matrix ◽  
Lung Tissue ◽  
Elastic System ◽  
Elastic Fiber ◽  
Dynamic Mechanical Properties ◽  
Tissue Mechanics ◽  
Matrix Composition ◽  
Elastic Fibers ◽  
Oxytalan Fibers

The dynamic mechanical properties of lung tissue and its contents of collagen and elastic fibers were studied in strips prepared from mice instilled intratracheally with saline (C) or silica [15 (S15) and 30 days (S30) after instillation]. Resistance, elastance, and hysteresivity were studied during oscillations at different frequencies on S15 and S30. Elastance increased from C to silica groups but was similar between S15 and S30. Resistance was augmented from C to S15 and S30 and was greater in S30 than in S15 at higher frequencies. Hysteresivity was higher in S30 than in C and S15. Silica groups presented a greater amount of collagen than did C. Elastic fiber content increased progressively along time. This increment was related to the higher amount of oxytalan fibers at 15 and 30 days, whereas elaunin and fully developed elastic fibers were augmented only at 30 days. Silicosis led not only to pulmonary fibrosis but also to fibroelastosis, thus assigning a major role to the elastic system in the silicotic lung.

Comparison of rat and mouse pulmonary tissue mechanical properties and histology

2002 ◽  
Vol 92 (1) ◽  
pp. 230-234 ◽  
Author(s):  
Débora S. Faffe ◽  
Patricia R. M. Rocco ◽  
Elnara M. Negri ◽  
Walter A. Zin
Keyword(s):  
Mechanical Properties ◽  
Blood Vessel ◽  
Elastic Fiber ◽  
Dynamic Mechanical Properties ◽  
Elastic Fibers ◽  
Rat Lung ◽  
Positive Dependence ◽  
Pulmonary Tissue ◽  
Sinusoidal Oscillations ◽  
The Mean

The present study compares the dynamic mechanical properties and the contents of collagen and elastic fibers (oxytalan + elaunin + fully developed elastic fibers) of mice and rat lung strips. Resistance, elastance (E), and hysteresivity (η) were obtained during sinusoidal oscillations. The relative amounts of blood vessel, bronchial, and alveolar walls, as well as the mean alveolar diameter were determined. In both species, resistance had a negative and E a positive dependence on frequency, whereas η remained unchanged. Mice showed higher E and lower η than rats. Although collagen and elastic fiber contents were similar in both groups, mice had more oxytalan and less elaunin and fully developed elastic fibers than rats. Rats showed less alveolar and more blood vessel walls and higher mean alveolar diameter than mice. In conclusion, mice and rats present distinct tissue mechanical properties, which are accompanied by specific extracellular fiber composition.

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