Journal articles: 'Tropoelastin'

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Saunders, N. A., and M. E. Grant. "The secretion of tropoelastin by chick-embryo artery cells." Biochemical Journal 230, no. 1 (August 15, 1985): 217–25. http://dx.doi.org/10.1042/bj2300217.

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Chymotryptic fingerprint analyses of tropoelastin a and tropoelastin b demonstrated a very close relationship between these two polypeptides synthesized in a cell-free system under the direction of chick-embryo polyribosomal mRNA. A similar study on tropoelastin polypeptides extracted in their hydroxylated and under-hydroxylated forms from artery cells incubated with [3H]valine in the absence and presence of alpha alpha'-bipyridine or 3,4-dehydroproline confirmed this close relationship and suggested that tropoelastins a and b are likely to be the products of a single gene. Pulse-chase experiments in which the synthesis and secretion of tropoelastin by artery cells were monitored demonstrated that, after a pulse with [3H]proline, the polypeptides rapidly appeared in the medium and the half-time of tropoelastin secretion was approx. 30 min. Further pulse-chase studies, in which [3H]tropoelastin contents of subcellular fractions were determined, showed that rough and smooth microsomal fractions contained maximal amounts of tropoelastin at different times. The quantity of tropoelastin in the smooth-microsomal fraction was always only a small proportion of that in the rough-microsomal fraction, suggesting rapid translocation of the polypeptides to the plasma membrane. Incubation of the cells with 0.1 mM-colchicine did not markedly alter the rate of secretion or the distribution of tropoelastin between the subcellular fractions, whereas when 1 microM-monensin was included in the incubations the polypeptides were retained in the rough microsomal fraction. The results are consistent with the proposal that tropoelastin may follow a pathway of secretion from rough endoplasmic reticulum to the plasma membrane via secretory vesicles.

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Wise, Steven G., and Anthony S. Weiss. "Tropoelastin." International Journal of Biochemistry & Cell Biology 41, no. 3 (March 2009): 494–97. http://dx.doi.org/10.1016/j.biocel.2008.03.017.

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Al Halawani, Aleen, Lea Abdulkhalek, Suzanne M. Mithieux, and Anthony S. Weiss. "Tropoelastin Promotes the Formation of Dense, Interconnected Endothelial Networks." Biomolecules 11, no. 9 (September 6, 2021): 1318. http://dx.doi.org/10.3390/biom11091318.

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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.

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Yeo, Giselle C., Anna Tarakanova, Clair Baldock, Steven G. Wise, Markus J. Buehler, and Anthony S. Weiss. "Subtle balance of tropoelastin molecular shape and flexibility regulates dynamics and hierarchical assembly." Science Advances 2, no. 2 (February 5, 2016): e1501145. http://dx.doi.org/10.1126/sciadv.1501145.

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The assembly of the tropoelastin monomer into elastin is vital for conferring elasticity on blood vessels, skin, and lungs. Tropoelastin has dual needs for flexibility and structure in self-assembly. We explore the structure-dynamics-function interplay, consider the duality of molecular order and disorder, and identify equally significant functional contributions by local and global structures. To study these organizational stratifications, we perturb a key hinge region by expressing an exon that is universally spliced out in human tropoelastins. We find a herniated nanostructure with a displaced C terminus and explain by molecular modeling that flexible helices are replaced with substantial β sheets. We see atypical higher-order cross-linking and inefficient assembly into discontinuous, thick elastic fibers. We explain this dysfunction by correlating local and global structural effects with changes in the molecule’s assembly dynamics. This work has general implications for our understanding of elastomeric proteins, which balance disordered regions with defined structural modules at multiple scales for functional assembly.

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Pierce, R. A., W. I. Mariencheck, S. Sandefur, E. C. Crouch, and W. C. Parks. "Glucocorticoids upregulate tropoelastin expression during late stages of fetal lung development." American Journal of Physiology-Lung Cellular and Molecular Physiology 268, no. 3 (March 1, 1995): L491—L500. http://dx.doi.org/10.1152/ajplung.1995.268.3.l491.

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The production of elastin, an essential extracellular matrix protein of terminal airway interstitium, occurs mostly during early development. Because glucocorticoids influence airway maturation, we studied the effect of dexamethasone (Dex) on tropoelastin expression during fetal lung development. Timed-pregnant rats were treated with Dex (1 mg/kg daily), and fetal lungs were collected 3 days later at 17, 19, and 21 days of gestation. Dex treatment resulted in about a threefold increase in tropoelastin mRNA levels at 19 days concomitant with accelerated airway development. By in situ hybridization, Dex treatment increased the number of tropoelastin-expressing cells and the level of tropoelastin mRNA per cell. In organ culture, Dex increased lung tropoelastin expression and augmented cortisol stimulation of tropoelastin expression. In fetal pulmonary artery smooth muscle cells, 10(-8) M Dex upregulated tropoelastin mRNA expression and increased tropoelastin promoter-chloramphenicol acetyl transferase activity in transient transfections. These data indicate that pharmacologically administered glucocorticoids transcriptionally upregulate fetal lung tropoelastin expression and suggest that steroid hormones may be important regulators of elastin production in vivo.

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Lee, Pearl, Daniel V. Bax, Marcela M. M. Bilek, and Anthony S. Weiss. "A Novel Cell Adhesion Region in Tropoelastin Mediates Attachment to Integrin αVβ5." Journal of Biological Chemistry 289, no. 3 (November 29, 2013): 1467–77. http://dx.doi.org/10.1074/jbc.m113.518381.

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Tropoelastin protein monomers assemble to form elastin. Cellular integrin αVβ3 binds RKRK at the C-terminal tail of tropoelastin. We probed cell interactions with tropoelastin by deleting the RKRK sequence to identify other cell-binding interactions within tropoelastin. We found a novel human dermal fibroblast attachment and spreading site on tropoelastin that is located centrally in the molecule. Inhibition studies demonstrated that this cell adhesion was not mediated by either elastin-binding protein or glycosaminoglycans. Cell interactions were divalent cation-dependent, indicating integrin dependence. Function-blocking monoclonal antibodies revealed that αV integrin(s) and integrin αVβ5 specifically were critical for cell adhesion to this part of tropoelastin. These data reveal a common αV integrin-binding theme for tropoelastin: αVβ3 at the C terminus and αVβ5 at the central region of tropoelastin. Each αV region contributes to fibroblast attachment and spreading, but they differ in their effects on cytoskeletal assembly.

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Bruce, Margaret C., and Catherine E. Honaker. "Transcriptional regulation of tropoelastin expression in rat lung fibroblasts: changes with age and hyperoxia." American Journal of Physiology-Lung Cellular and Molecular Physiology 274, no. 6 (June 1, 1998): L940—L950. http://dx.doi.org/10.1152/ajplung.1998.274.6.l940.

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Elastic fibers are thought to provide structural support for secondary septa as the lung undergoes the transition from the saccular to the alveolar stage. The synthesis of the soluble precursor of elastin, tropoelastin, occurs during a finite developmental period. We have investigated the developmental regulation of tropoelastin gene transcription and mRNA expression in fetal and postnatal rat lung fibroblasts and have assessed the changes in tropoelastin gene expression caused by hyperoxic exposure during secondary septal development. With the use of an RT-PCR assay and intron-specific primers to detect heterogeneous nuclear RNA (hnRNA) and intron-spanning primers to detect mRNA in freshly isolated rat lung fibroblasts, tropoelastin gene expression was found to be upregulated late in gestation. From days 18 to 21 of gestation, there was a 4.5-fold increase in tropoelastin hnRNA ( P < 0.0001) and a 6-fold increase in mRNA ( P = 0.002). After birth, tropoelastin expression was downregulated. Signals decreased from fetal day 21 to postnatal day 2 for both tropoelastin hnRNA ( P = 0.021) and mRNA ( P = 0.043). Tropoelastin hnRNA decreased further from days 2 to 6 ( P= 0.04). Both tropoelastin hnRNA and mRNA were again upregulated during alveolarization from days 9 to 11, indicating that, once upregulated, transcription of the tropoelastin gene is not constant but varies with fetal and postnatal age. Exposure to >95% oxygen, when initiated on postnatal day 2 or 3 and continued until day 11, significantly diminished the developmental increase in tropoelastin hnRNA ( P < 0.005) and mRNA ( P < 0.05) normally seen on days 9– 11, indicating that the postnatal upregulation of tropoelastin gene expression is inhibited by hyperoxic exposure in the early postnatal period.

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Weiss, Anthony S. "Perspectives on the Molecular and Biological Implications of Tropoelastin in Human Tissue Elasticity." Australian Journal of Chemistry 69, no. 12 (2016): 1380. http://dx.doi.org/10.1071/ch16452.

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The elasticity of a range of vertebrate and particularly human tissues depends on the dynamic and persistent protein elastin. This elasticity is diverse, and comprises skin, blood vessels, and lung, and is essential for tissue viability. Elastin is predominantly made by assembling tropoelastin, which is an asymmetric 20-nm-long protein molecule. This overview considers tropoelastin’s molecular features and biological interactions in the context of its value in tissue repair.

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Ford, Audrey C., Hans Machula, Robert S. Kellar, and Brent A. Nelson. "Characterizing the mechanical properties of tropoelastin protein scaffolds." MRS Proceedings 1569 (2013): 45–50. http://dx.doi.org/10.1557/opl.2013.1059.

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ABSTRACTThis paper reports on mechanical characterization of electrospun tissue scaffolds formed from varying blends of collagen and human tropoelastin. The electrospun tropoelastin-based scaffolds have an open, porous structure conducive to cell attachment and have been shown to exhibit strong biocompatibility, but the mechanical character is not well known. Mechanical properties were tested for scaffolds consisting of 100% tropoelastin and 1:1 tropoelastin-collagen blends. The results showed that the materials exhibited a three order of magnitude change in the initial elastic modulus when tested dry vs. hydrated, with moduli of 21 MPa and 0.011 MPa respectively. Noncrosslinked and crosslinked tropoelastin scaffolds exhibited the same initial stiffness from 0 to 50% strain, and the noncrosslinked scaffolds exhibited no stiffness at strains >∼50%. The elastic modulus of a 1:1 tropoelastin-collagen blend was 50% higher than that of a pure tropoelastin scaffold. Finally, the 1:1 tropoelastin-collagen blend was five times stiffer from 0 to 50% strain when strained at five times the ASTM standard rate. By systematically varying protein composition and crosslinking, the results demonstrate how protein scaffolds might be manipulated as customized biomaterials, ensuring mechanical robustness and potentially improving biocompatibility through minimization of compliance mismatch with the surrounding tissue environment. Moreover, the demonstration of strain-rate dependent mechanical behavior has implications for mechanical design of tropoelastin-based tissue scaffolds.

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Tinker, D., J. Geller, N. Romero, C. E. Cross, and R. B. Rucker. "Tropoelastin production and tropoelastin messenger RNA activity. Relationship to copper and elastin cross-linking in chick aorta." Biochemical Journal 237, no. 1 (July 1, 1986): 17–23. http://dx.doi.org/10.1042/bj2370017.

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The elastin content of the chick thoracic aorta increases 2--3-fold during the first 3 weeks post-hatching. The deposition of elastin requires the covalent cross-linking of tropoelastin by means of lysine-derived cross-links. This process is sensitive to dietary copper intake, since copper serves as cofactor for lysyl oxidase, the enzyme that catalyses the oxidative deamination of the lysine residues involved in cross-link formation. Disruption of cross-linking alters tissue concentrations of both elastin and tropoelastin and results in a net decrease in aortic elastin content. Autoregulation of tropoelastin synthesis by changes in the pool sizes of elastin or tropoelastin has been suggested as a possible mechanism for the diminished aortic elastin content. Consequently, dietary copper deficiency was induced to study the effect of impaired elastin cross-link formation on tropoelastin synthesis. Elastin in aortae from copper-deficient chicks was only two-thirds to one-half the amount measured in copper-supplemented chicks, whereas copper-deficient concentrations of tropoelastin in aorta were at least 5-fold higher than normal. In spite of these changes, however, increased amounts of tropoelastin, copper deficiency and decreased amounts of elastin did not influence the amounts of functional elastin mRNA in aorta. Likewise, the production of tropoelastin in aorta explants was the same whether the explants were taken from copper-sufficient or -deficient birds. The lower accumulation of elastin in aorta from copper-deficient chicks appeared to be due to extracellular proteolysis, rather than to a decrease in the rate of synthesis. Electrophoresis of aorta extracts, followed by immunological detection of tropoelastin-derived products, indicated degradation products in aortae from copper-deficient birds. In extracts of aortae from copper-sufficient chicks, tropoelastin was not degraded and appeared to be incorporated into elastin without further proteolytic processing.

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DiCamillo, Sandra J., Shenghong Yang, Maria V. Panchenko, Paul A. Toselli, Estee F. Naggar, Celeste B. Rich, Phillip J. Stone, Matthew A. Nugent, and Mikhail P. Panchenko. "Neutrophil elastase-initiated EGFR/MEK/ERK signaling counteracts stabilizing effect of autocrine TGF-β on tropoelastin mRNA in lung fibroblasts." American Journal of Physiology-Lung Cellular and Molecular Physiology 291, no. 2 (August 2006): L232—L243. http://dx.doi.org/10.1152/ajplung.00530.2005.

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Neutrophil elastase (NE) plays an important role in emphysema, a pulmonary disease associated with excessive elastolysis and ineffective repair of interstitial elastin. Besides its direct elastolytic activity, NE releases soluble epidermal growth factor receptor (EGFR) ligands and initiates EGFR/MEK/ERK signaling to downregulate tropoelastin mRNA in neonatal rat lung fibroblasts (DiCamillo SJ, Carreras I, Panchenko MV, Stone PJ, Nugent MA, Foster JA, and Panchenko MP. J Biol Chem 277: 18938–18946, 2002). We now report that NE downregulates tropoelastin mRNA in the rat fetal lung fibroblast line RFL-6. The tropoelastin mRNA downregulation is preceded by release of EGF-like and TGF-α-like polypeptides and requires EGFR/MEK/ERK signaling, because it is prevented by the EGFR inhibitor AG1478 and the MEK/ERK uncoupler U0126. Tropoelastin expression in RFL-6 fibroblasts is governed by autocrine TGF-β signaling, because TGF-β type I receptor kinase inhibitor or TGF-β neutralizing antibody dramatically decreases tropoelastin mRNA and protein levels. Half-life of tropoelastin mRNA in RFL-6 cells is >24 h, but it is decreased to ∼8 h by addition of TGF-β neutralizing antibody, EGF, TGF-α, or NE. Tropoelastin mRNA destabilization by NE, EGF, or TGF-α is abolished by AG1478 or U0126. EGF-dependent tropoelastin mRNA downregulation is reversed upon ligand withdrawal, whereas chronic EGF treatment leads to persistent downregulation of tropoelastin mRNA and protein levels and decreases insoluble elastin deposition. We conclude that NE-initiated EGFR/MEK/ERK signaling cascade overrides the autocrine TGF-β signaling on tropoelastin mRNA stability and, therefore, decreases the elastogenic response in RFL-6 fibroblasts. We hypothesize that persistent EGFR/MEK/ERK signaling could impede the TGF-β-induced elastogenesis/elastin repair in the chronically inflamed, elastase/anti-elastase imbalanced lung in emphysema.

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Berk, John L., Nima Massoomi, Christine Hatch, and Ronald H. Goldstein. "Hypoxia downregulates tropoelastin gene expression in rat lung fibroblasts by pretranslational mechanisms." American Journal of Physiology-Lung Cellular and Molecular Physiology 277, no. 3 (September 1, 1999): L566—L572. http://dx.doi.org/10.1152/ajplung.1999.277.3.l566.

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Elastolytic lung injury disrupts cell barriers, flooding alveoli and producing regional hypoxia. Abnormal O2 tensions may alter repair of damaged elastin fibers. To determine the effect of hypoxia on extravascular elastin formation, we isolated rat lung fibroblasts and cultured them under a variety of O2 conditions. Hypoxia downregulated tropoelastin mRNA in a dose- and time-related fashion while upregulating glyceraldehyde-3-phosphate dehydrogenase mRNA levels. The changes in tropoelastin gene expression were not due to cell toxicity as measured by chromium release and cell proliferation studies. Neither cycloheximide nor actinomycin D abrogated this effect. Hypoxia induced early decreases in tropoelastin mRNA stability; minor suppression of gene transcription occurred later. When returned to 21% O2, tropoelastin mRNA recovered to control levels in part by upregulating tropoelastin gene transcription. Taken together, these data indicate that hypoxia regulates tropoelastin gene expression and may alter repair of acutely injured lung.

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Davis, Elaine C., Thomas J. Broekelmann, Yuji Ozawa, and Robert P. Mecham. "Identification of Tropoelastin as a Ligand for the 65-kD FK506-binding Protein, FKBP65, in the Secretory Pathway." Journal of Cell Biology 140, no. 2 (January 26, 1998): 295–303. http://dx.doi.org/10.1083/jcb.140.2.295.

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The folding and trafficking of tropoelastin is thought to be mediated by intracellular chaperones, although the identity and role of any tropoelastin chaperone remain to be determined. To identify proteins that are associated with tropoelastin intracellularly, bifunctional chemical cross-linkers were used to covalently stabilize interactions between tropoelastin and associated proteins in the secretory pathway in intact fetal bovine auricular chondrocytes. Immunoprecipitation of tropoelastin from cell lysates after cross-linking and analysis by SDS-PAGE showed the presence of two proteins of ∼74 kD (p74) and 78 kD (p78) that coimmunoprecipitated with tropoelastin. Microsequencing of peptide fragments from a cyanogen bromide digest of p78 identified this protein as BiP and sequence analysis identified p74 as the peptidyl-prolyl cis–trans isomerase, FKPB65. The appearance of BiP and FKBP65 in the immunoprecipitations could be enhanced by the addition of brefeldin A (BFA) and N-acetyl-leu-leu-norleucinal (ALLN) to the culture medium for the final 4 h of labeling. Tropoelastin accumulates in the fused ER/Golgi compartment in the presence of BFA if its degradation is inhibited by ALLN (Davis, E.C., and R.P. Mecham. 1996. J. Biol. Chem. 271:3787–3794). The use of BFA and other secretion-disrupting agents suggests that the association of tropoelastin with FKBP65 occurs in the ER. Results from this study provide the first identification of a ligand for an FKBP in the secretory pathway and suggest that the prolyl cis–trans isomerase activity of FKBP65 may be important for the proper folding of the proline-rich tropoelastin molecule before secretion.

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Zhang, Mancong, Richard A. Pierce, Hiroshi Wachi, Robert P. Mecham, and William C. Parks. "An Open Reading Frame Element Mediates Posttranscriptional Regulation of Tropoelastin and Responsiveness to Transforming Growth Factor β1." Molecular and Cellular Biology 19, no. 11 (November 1, 1999): 7314–26. http://dx.doi.org/10.1128/mcb.19.11.7314.

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ABSTRACT Elastin, an extracellular component of arteries, lung, and skin, is produced during fetal and neonatal growth. We reported previously that the cessation of elastin production is controlled by a posttranscriptional mechanism. Although tropoelastin pre-mRNA is transcribed at the same rate in neonates and adults, marked instability of the fully processed transcript bars protein production in mature tissue. Using RNase protection, we identified a 10-nucleotide sequence in tropoelastin mRNA near the 5′ end of the sequences coded by exon 30 that interacts specifically with a developmentally regulated cytosolic 50-kDa protein. Binding activity increased as tropoelastin expression dropped, being low in neonatal fibroblasts and high in adult cells, and treatment with transforming growth factor β1 (TGF-β1), which stimulates tropoelastin expression by stabilizing its mRNA, reduced mRNA-binding activity. No other region of tropoelastin mRNA interacted with cellular proteins, and no binding activity was detected in nuclear extracts. The ability of the exon-30 element to control mRNA decay and responsiveness to TGF-β1 was assessed by three distinct functional assays: (i) insertion of exon 30 into a heterologous gene conferred increased reporter activity after exposure to TGF-β1; (ii) addition of excess exon 30 RNA slowed tropoelastin mRNA decay in an in vitro polysome degradation assay; and (iii) a mutant tropoelastin cDNA lacking exon 30, compared to wild-type cDNA, produced a stable transcript whose levels were not affected by TGF-β1. These findings demonstrate that posttranscriptional regulation of elastin production in mature tissue is conferred by a specific element within the open reading frame of tropoelastin mRNA.

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Yeo, Giselle C., and Anthony S. Weiss. "Soluble matrix protein is a potent modulator of mesenchymal stem cell performance." Proceedings of the National Academy of Sciences 116, no. 6 (January 18, 2019): 2042–51. http://dx.doi.org/10.1073/pnas.1812951116.

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We challenge the conventional designation of structural matrix proteins primarily as supporting scaffolds for resident cells. The extracellular matrix protein tropoelastin is classically regarded as a structural component that confers mechanical strength and resilience to tissues subject to repetitive elastic deformation. Here we describe how tropoelastin inherently induces a range of biological responses, even in cells not typically associated with elastic tissues and in a manner unexpected of typical substrate-dependent matrix proteins. We show that tropoelastin alone drives mesenchymal stem cell (MSC) proliferation and phenotypic maintenance, akin to the synergistic effects of potent growth factors such as insulin-like growth factor 1 and basic fibroblast growth factor. In addition, tropoelastin functionally surpasses these growth factors, as well as fibronectin, in allowing substantial media serum reduction without loss of proliferative potential. We further demonstrate that tropoelastin elicits strong mitogenic and cell-attractive responses, both as an immobilized substrate and as a soluble additive, via direct interactions with cell surface integrins αvβ3 and αvβ5. This duality of action converges the long-held mechanistic dichotomy between adhesive matrix proteins and soluble growth factors and uncovers the powerful, untapped potential of tropoelastin for clinical MSC expansion and therapeutic MSC recruitment. We propose that the potent, growth factor-like mitogenic and motogenic abilities of tropoelastin are biologically rooted in the need for rapid stem cell homing and proliferation during early development and/or wound repair.

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Grosso, L. E., W. C. Parks, L. J. Wu, and R. P. Mecham. "Fibroblast adhesion to recombinant tropoelastin expressed as a protein A-fusion protein." Biochemical Journal 273, no. 3 (February 1, 1991): 517–22. http://dx.doi.org/10.1042/bj2730517.

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A bovine tropoelastin cDNA encoding exons 15-36 that includes the elastin-receptor binding site was expressed in Escherichia coli as a fusion protein with Protein A from Staphylococcus aureus. After isolation of the fusion protein by affinity chromatography on Ig-Sepharose, the tropoelastin domain was separated from plasmid-pR1T2T-encoded Protein A (Protein A') by CNBr cleavage. Cell-adhesion assays demonstrated specific adhesion to the recombinant tropoelastin. Furthermore, the data indicate that interactions involving the bovine elastin receptor mediate nuchalligament fibroblast adhesion to the recombinant protein. In agreement with earlier studies of fibroblast chemotaxis to bovine tropoelastin, nuchal-ligament fibroblast adhesion demonstrated developmental regulation of the elastin receptor.

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Frisch, S. M., J. M. Davidson, and Z. Werb. "Blockage of tropoelastin secretion by monensin represses tropoelastin synthesis at a pretranslational level in rat smooth muscle cells." Molecular and Cellular Biology 5, no. 1 (January 1985): 253–58. http://dx.doi.org/10.1128/mcb.5.1.253-258.1985.

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The blockage of protein secretion in the R22 cultured rat aortic smooth muscle cell strain with monensin repressed tropoelastin gene expression at the mRNA level by ca. 50-fold as measured by biosynthetic pulse-labeling, in vitro translation, and hybridization with a tropoelastin genomic DNA probe. These results suggest that tropoelastin gene expression is autoregulated, and they represent the first reported effect of monensin on gene expression.

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Frisch, S. M., J. M. Davidson, and Z. Werb. "Blockage of tropoelastin secretion by monensin represses tropoelastin synthesis at a pretranslational level in rat smooth muscle cells." Molecular and Cellular Biology 5, no. 1 (January 1985): 253–58. http://dx.doi.org/10.1128/mcb.5.1.253.

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The blockage of protein secretion in the R22 cultured rat aortic smooth muscle cell strain with monensin repressed tropoelastin gene expression at the mRNA level by ca. 50-fold as measured by biosynthetic pulse-labeling, in vitro translation, and hybridization with a tropoelastin genomic DNA probe. These results suggest that tropoelastin gene expression is autoregulated, and they represent the first reported effect of monensin on gene expression.

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Yang, Shenghong, Matthew A. Nugent, and Mikhail P. Panchenko. "EGF antagonizes TGF-β-induced tropoelastin expression in lung fibroblasts via stabilization of Smad corepressor TGIF." American Journal of Physiology-Lung Cellular and Molecular Physiology 295, no. 1 (July 2008): L143—L151. http://dx.doi.org/10.1152/ajplung.00289.2007.

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We previously reported that neutrophil elastase (NE) downregulates transforming growth factor-β (TGF-β)-maintained tropoelastin mRNA levels in lung fibroblasts through transactivation of the epidermal growth factor (EGF) receptor (EGFR)/Mek/Erk pathway, which is dependent on the NE-initiated release of soluble EGFR ligands. In the present study, we investigated the mechanism by which EGF downregulates tropoelastin expression. We found that EGF downregulates tropoelastin expression through inhibition of TGF-β signaling. We show that EGF does not prevent the TGF-β-induced nuclear accumulation of Smad2/3; rather, EGF stabilizes the short-lived Smad transcriptional corepressor TG-interacting factor (TGIF) via EGFR/Mek/Erk-mediated phosphorylation of TGIF. Elevation of TGIF levels, either by TGIF overexpression or prevention of TGIF degradation, is sufficient to inhibit TGF-β-induced tropoelastin expression. Moreover, TGIF is essential for EGF-mediated downregulation of tropoelastin expression, inasmuch as small interfering RNA knockdown of TGIF blocked EGF-induced downregulation of tropoelastin. Finally, we demonstrated that NE treatment, which releases EGF-like growth factors, causes stabilization of TGIF through the EGFR/Mek/Erk pathway. These results suggest that EGFR/Mek/Erk signaling specifically antagonizes the proelastogenic action of TGF-β in lung fibroblasts by stabilizing the Smad transcriptional corepressor TGIF.

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Vrhovski, Bernadette, and Anthony S. Weiss. "Biochemistry of tropoelastin." European Journal of Biochemistry 258, no. 1 (November 15, 1998): 1–18. http://dx.doi.org/10.1046/j.1432-1327.1998.2580001.x.

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Yeo, Giselle C., Fred W. Keeley, and Anthony S. Weiss. "Coacervation of tropoelastin." Advances in Colloid and Interface Science 167, no. 1-2 (September 2011): 94–103. http://dx.doi.org/10.1016/j.cis.2010.10.003.

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Patterson, Charles E., Theresa Schaub, Elaine J. Coleman, and Elaine C. Davis. "Developmental Regulation of FKBP65." Molecular Biology of the Cell 11, no. 11 (November 2000): 3925–35. http://dx.doi.org/10.1091/mbc.11.11.3925.

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FKBP65 (65-kDa FK506-binding protein) is a member of the highly conserved family of intracellular receptors called immunophilins. All have the property of peptidyl-prolyl cis-trans isomerization, and most have been implicated in folding and trafficking events. In an earlier study, we identified that FKBP65 associates with the extracellular matrix protein tropoelastin during its transport through the cell. In the present study, we have carried out a detailed investigation of the subcellular localization of FKBP65 and its relationship to tropoelastin. Using subcellular fractionation, Triton X-114 phase separation, protease protection assays, and immunofluorescence microscopy (IF), we have identified that FKBP65 is contained within the lumen of the endoplasmic reticulum (ER). Subsequent IF studies colocalized FKBP65 with tropoelastin and showed that the two proteins dissociate before reaching the Golgi apparatus. Immunohistochemical localization of FKBP65 in developing lung showed strong staining of vascular and airway smooth muscle cells. Similar areas stained positive for the presence of elastic fibers in the extracellular matrix. The expression of FKBP65 was investigated during development as tropoelastin is not expressed in adult tissues. Tissue-specific expression of FKBP65 was observed in 12-d old mouse tissues; however, the pattern of expression of FKBP65 was not restricted to those tissues expressing tropoelastin. This suggests that additional ligands for FKBP65 likely exist within the ER. Remarkably, in the adult tissues examined, FKBP65 expression was absent or barely detectable. Taken together, these results support an ER-localized FKBP65-tropoelastin interaction that occurs specifically during growth and development of tissues.

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Robb, Bruce W., Hiroshi Wachi, Theresa Schaub, Robert P. Mecham, and Elaine C. Davis. "Characterization of an In Vitro Model of Elastic Fiber Assembly." Molecular Biology of the Cell 10, no. 11 (November 1999): 3595–605. http://dx.doi.org/10.1091/mbc.10.11.3595.

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Elastic fibers consist of two morphologically distinct components: elastin and 10-nm fibrillin-containing microfibrils. During development, the microfibrils form bundles that appear to act as a scaffold for the deposition, orientation, and assembly of tropoelastin monomers into an insoluble elastic fiber. Although microfibrils can assemble independent of elastin, tropoelastin monomers do not assemble without the presence of microfibrils. In the present study, immortalized ciliary body pigmented epithelial (PE) cells were investigated for their potential to serve as a cell culture model for elastic fiber assembly. Northern analysis showed that the PE cells express microfibril proteins but do not express tropoelastin. Immunofluorescence staining and electron microscopy confirmed that the microfibril proteins produced by the PE cells assemble into intact microfibrils. When the PE cells were transfected with a mammalian expression vector containing a bovine tropoelastin cDNA, the cells were found to express and secrete tropoelastin. Immunofluorescence and electron microscopic examination of the transfected PE cells showed the presence of elastic fibers in the matrix. Biochemical analysis of this matrix showed the presence of cross-links that are unique to mature insoluble elastin. Together, these results indicate that the PE cells provide a unique, stable in vitro system in which to study elastic fiber assembly.

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FREEMAN, Lyle J., Amanda LOMAS, Nigel HODSON, Michael J. SHERRATT, Kieran T. MELLODY, Anthony S. WEISS, Adrian SHUTTLEWORTH, and Cay M. KIELTY. "Fibulin-5 interacts with fibrillin-1 molecules and microfibrils." Biochemical Journal 388, no. 1 (May 10, 2005): 1–5. http://dx.doi.org/10.1042/bj20050368.

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Fibulin-5 plays an important role in elastic fibre formation in vivo. We have investigated the molecular interactions between fibulin-5 and components of fibrillin-rich microfibrils which form a template for elastin. Fibulin-5 interacted in a dose-dependent manner with a fibrillin-1 N-terminal sequence and with tropoelastin, but not with MAGP-1 (microfibril-associated glycoprotein-1) or decorin. Fibulin-5 did not inhibit interactions between fibrillin-1 N- and C-terminal fragments, or fibrillin-1 interactions with tropoelastin. Fibulin-5 may provide a link between tropoelastin and microfibrils in the pericellular space during elastic fibre assembly.

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BROWN-AUGSBURGER, Patricia, Thomas BROEKELMANN, Joel ROSENBLOOM, and Robert P. MECHAM. "Functional domains on elastin and microfibril-associated glycoprotein involved in elastic fibre assembly." Biochemical Journal 318, no. 1 (August 15, 1996): 149–55. http://dx.doi.org/10.1042/bj3180149.

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Studies in vitro suggest that the C-terminus of tropoelastin mediates elastin polymerization through an interaction with microfibril-associated proteins. In this study we have used cultured auricular chondrocytes as a model system to examine whether this interaction is critical for elastic fibre formation in vivo. Auricular chondrocytes, which deposit an abundant elastic fibre matrix, were cultured in the presence of Fab fragments of antibodies directed against the C-terminus (CTe) or an N-terminal domain (ATe) of tropoelastin. Immunofluorescent staining of the extracellular matrix deposited by the cells showed that the CTe antibody inhibited the deposition of elastin without affecting microfibril structure. Cells grown under identical conditions in the presence of ATe, however, formed fibres that stained normally for both elastin and microfibril proteins. Chondrocytes cultured in the presence of microfibril-associated glycoprotein (MAGP):21–35, an antibody directed against a domain near the N-terminus of MAGP, did not organize tropoelastin into fibres. However, immunostaining for MAGP and fibrillin revealed normal microfibrils. In agreement with the immunofluorescence staining patterns, fewer elastin-specific cross-links, indicative of insoluble elastin, were detected in the extracellular matrix of cells cultured in the presence of CTe. The medium from these cultures, however, contained more soluble elastin, consistent with an antibody-induced alteration of elastin assembly but not its synthesis. Northern analysis of antibody-treated and control cultures substantiated equivalent levels of tropoelastin mRNA. These results confirm that the C-terminus of tropoelastin interacts with microfibrils during the assembly of elastic fibres. Further, the results suggest that the interaction between tropoelastin and microfibrils might be mediated by a domain involving the N-terminal half of MAGP.

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Baule, Valerie J., and Judith Ann Foster. "Multiple chick tropoelastin mRNAs." Biochemical and Biophysical Research Communications 154, no. 3 (August 1988): 1054–60. http://dx.doi.org/10.1016/0006-291x(88)90247-1.

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Davis, Elaine C., and Robert P. Mecham. "Intracellular trafficking of tropoelastin." Matrix Biology 17, no. 4 (August 1998): 245–54. http://dx.doi.org/10.1016/s0945-053x(98)90078-6.

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Hirai, Maretoshi, Tetsuya Ohbayashi, Masahito Horiguchi, Katsuya Okawa, Akari Hagiwara, Kenneth R. Chien, Toru Kita, and Tomoyuki Nakamura. "Fibulin-5/DANCE has an elastogenic organizer activity that is abrogated by proteolytic cleavage in vivo." Journal of Cell Biology 176, no. 7 (March 19, 2007): 1061–71. http://dx.doi.org/10.1083/jcb.200611026.

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Elastic fibers are required for the elasticity and integrity of various organs. We and others previously showed that fibulin-5 (also called developing arteries and neural crest EGF-like [DANCE] or embryonic vascular EGF-like repeat–containing protein [EVEC]) is indispensable for elastogenesis by studying fibulin-5–deficient mice, which recapitulate human aging phenotypes caused by disorganized elastic fibers (Nakamura, T., P.R. Lozano, Y. Ikeda, Y. Iwanaga, A. Hinek, S. Minamisawa, C.F. Cheng, K. Kobuke, N. Dalton, Y. Takada, et al. 2002. Nature. 415:171–175; Yanagisawa, H., E.C. Davis, B.C. Starcher, T. Ouchi, M. Yanagisawa, J.A. Richardson, and E.N. Olson. 2002. Nature. 415:168–171). However, the molecular mechanism by which fiblin-5 contributes to elastogenesis remains unknown. We report that fibulin-5 protein potently induces elastic fiber assembly and maturation by organizing tropoelastin and cross-linking enzymes onto microfibrils. Deposition of fibulin-5 on microfibrils promotes coacervation and alignment of tropoelastins on microfibrils, and also facilitates cross-linking of tropoelastin by tethering lysyl oxidase-like 1, 2, and 4 enzymes. Notably, recombinant fibulin-5 protein induced elastogenesis even in serum-free conditions, although elastogenesis in cell culture has been believed to be serum-dependent. Moreover, the amount of full-length fibulin-5 diminishes with age, while truncated fibulin-5, which cannot promote elastogenesis, increases. These data suggest that fibulin-5 could be a novel therapeutic target for elastic fiber regeneration.

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Yeo, Giselle C., Alexey Kondyurin, Elena Kosobrodova, Anthony S. Weiss, and Marcela M. M. Bilek. "A sterilizable, biocompatible, tropoelastin surface coating immobilized by energetic ion activation." Journal of The Royal Society Interface 14, no. 127 (February 2017): 20160837. http://dx.doi.org/10.1098/rsif.2016.0837.

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Biomimetic materials which integrate with surrounding tissues and regulate new tissue formation are attractive for tissue engineering and regenerative medicine. Plasma immersion ion-implanted (PIII) polyethersulfone (PES) provides an excellent platform for the irreversible immobilization of bioactive proteins and peptides. PIII treatment significantly improves PES wettability and results in the formation of acidic groups on the PES surface, with the highest concentration observed at 40–80 s of PIII treatment. The elastomeric protein tropoelastin can be stably adhered to PIII-treated PES in a cell-interactive conformation by tailoring the pH and salt levels of the protein–surface association conditions. Tropoelastin-coated PIII-treated PES surfaces are resistant to molecular fouling, and actively promote high levels of fibroblast adhesion and proliferation while maintaining cell morphology. Tropoelastin, unlike other extracellular matrix proteins such as fibronectin, uniquely retains full bioactivity even after medical-grade ethylene oxide sterilization. This dual approach of PIII treatment and tropoelastin cloaking allows for the stable, robust functionalization of clinically used polymer materials for directed cellular interactions.

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Chen, Qiuyun, Teng Zhang, Joseph F. Roshetsky, Zhufeng Ouyang, Jeroen Essers, Chun Fan, Qing Wang, Aleksander Hinek, Edward F. Plow, and Paul E. Dıcorleto. "Fibulin-4 regulates expression of the tropoelastin gene and consequent elastic-fibre formation by human fibroblasts." Biochemical Journal 423, no. 1 (September 14, 2009): 79–89. http://dx.doi.org/10.1042/bj20090993.

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Elastic fibres are essential for normal physiology in numerous tissues, including arteries, lungs and skin. Fibulin-4 is an elastic-fibre-associated glycoprotein that is indispensable for elastic-fibre formation in mice. However, the mechanism by which fibulin-4 executes this function remains to be determined. Here, we established an in vitro functional assay system in which fibulin-4 was knocked down in human foreskin fibroblasts using siRNA (small interfering RNA) technology. With two different siRNAs, substantial knockdown of fibulin-4 was achieved, and this suppression was associated with impaired elastic-fibre formation by the fibroblasts. Real-time reverse transcription–PCR analysis showed that knockdown of fibulin-4 expression was accompanied by reduced expression of tropoelastin mRNA. Further analysis showed that this decrease was caused by transcriptional down-regulation of tropoelastin. This effect was selective, since the mRNA level of other elastic-fibre-associated proteins, including fibrillin-1, lysyl oxidase and lysyl oxidase-like-1, was not affected. Moreover, addition of conditioned medium from cultures of CHO (Chinese-hamster ovary) cells overexpressing fibulin-4 stimulated tropoelastin expression and elastic-fibre formation in cultures of Williams–Beuren-syndrome fibroblasts. Knocking down or knocking out fibulin-4 in mice led to a decrease in tropoelastin expression in the aorta. These results indicate that fibulin-4, considered as a structural protein, may also participate in regulating elastic-fibre formation in human cells through an unanticipated mechanism, namely the regulation of tropoelastin expression.

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Nakamura, Tomohiko, Mingyao Liu, Eric Mourgeon, Art Slutsky, and Martin Post. "Mechanical strain and dexamethasone selectively increase surfactant protein C and tropoelastin gene expression." American Journal of Physiology-Lung Cellular and Molecular Physiology 278, no. 5 (May 1, 2000): L974—L980. http://dx.doi.org/10.1152/ajplung.2000.278.5.l974.

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Physical forces derived from fetal breathing movements and hormones such as glucocorticoids are implicated in regulating fetal lung development. To elucidate whether the different signaling pathways activated by physical and hormonal factors are integrated and coordinated at the cellular and transcriptional levels, organotypic cultures of mixed fetal rat lung cells were subjected to static culture or mechanical strain in the presence and absence of dexamethasone. Tropoelastin and collagen type I were used as marker genes for fibroblasts, whereas surfactant protein (SP) A and SP-C were used as marker genes for distal epithelial cells. Mechanical strain, but not dexamethasone, significantly increased SP-C mRNA expression. Tropoelastin mRNA expression was upregulated by both mechanical strain and dexamethasone. No additive or synergistic effect was observed when cells were subjected to mechanical stretch in the presence of dexamethasone. Neither mechanical strain nor dexamethasone alone or in combination had any significant effect on the expression of SP-A mRNA. Dexamethasone decreased collagen type I mRNA expression, whereas mechanical strain had no effect. The increases in tropoelastin and SP-C mRNA levels induced by mechanical strain and/or dexamethasone were accompanied by increases in their heterogeneous nuclear RNA. In addition, the stretch- and glucocorticoid-induced alterations in tropoelastin and SP-C mRNA expression were abrogated with 10 μg/ml actinomycin D. These findings suggest that tropoelastin and SP-C genes are selectively stimulated by physical and/or hormonal factors at the transcriptional level in fetal lung fibroblasts and distal epithelial cells, respectively.

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Prosser, Ian W., Loren A. Whitehouse, William C. Parks, Mona Stahle-backdahl, Aleksander Hinek, Pyong Woo Park, and Robert P. Mecham. "Polyclonal antibodies to tropoelastin and the specific detection and measurement of tropoelastinin vitro." Connective Tissue Research 25, no. 3-4 (January 1991): 265–79. http://dx.doi.org/10.3109/03008209109029162.

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Fornieri, C., M. Baccarani-Contri, D. Quaglino, and I. Pasquali-Ronchetti. "Lysyl oxidase activity and elastin/glycosaminoglycan interactions in growing chick and rat aortas." Journal of Cell Biology 105, no. 3 (September 1, 1987): 1463–69. http://dx.doi.org/10.1083/jcb.105.3.1463.

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Hydrophobic tropoelastin molecules aggregate in vitro in physiological conditions and form fibers very similar to natural ones (Bressan, G. M., I. Pasquali Ronchetti, C. Fornieri, F. Mattioli, I. Castellani, and D. Volpin, 1986, J. Ultrastruct. Molec. Struct. Res., 94:209-216). Similar hydrophobic interactions might be operative in in vivo fibrogenesis. Data are presented suggesting that matrix glycosaminoglycans (GAGs) prevent spontaneous tropoelastin aggregation in vivo, at least up to the deamination of lysine residues on tropoelastin by matrix lysyl oxidase. Lysyl oxidase inhibitors beta-aminopropionitrile, aminoacetonitrile, semicarbazide, and isonicotinic acid hydrazide were given to newborn chicks, to chick embryos, and to newborn rats, and the ultrastructural alterations of the aortic elastic fibers were analyzed and compared with the extent of the enzyme inhibition. When inhibition was greater than 65% all chemicals induced alterations of elastic fibers in the form of lateral aggregates of elastin, which were always permeated by cytochemically and immunologically recognizable GAGs. The number and size of the abnormal elastin/GAGs aggregates were proportional to the extent of lysyl oxidase inhibition. The phenomenon was independent of the animal species. All data suggest that, upon inhibition of lysyl oxidase, matrix GAGs remain among elastin molecules during fibrogenesis by binding to positively charged amino groups on elastin. Newly synthesized and secreted tropoelastin has the highest number of free epsilon amino groups, and, therefore, the highest capability of binding to GAGs. These polyanions, by virtue of their great hydration and dispersing power, could prevent random spontaneous aggregation of hydrophobic tropoelastin in the extracellular space.

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Hinek, A., and M. Rabinovitch. "67-kD elastin-binding protein is a protective "companion" of extracellular insoluble elastin and intracellular tropoelastin." Journal of Cell Biology 126, no. 2 (July 15, 1994): 563–74. http://dx.doi.org/10.1083/jcb.126.2.563.

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The 67-kD elastin-binding protein (EBP) mediates cell adhesion to elastin and elastin fiber assembly, and it is similar, if not identical, to the 67-kD enzymatically inactive, alternatively spliced beta-galactosidase. The latter contains an elastin binding domain (S-GAL) homologous both to the aorta EBP and to NH2-terminal sequences of serine proteinases (Hinek, A., M. Rabinovitch, F. W. Keeley, and J. Callahan. 1993. J. Clin. Invest. 91:1198-1205). We now confirm the functional importance of this homology by showing that elastolytic activity of a representative serine elastase, porcine pancreatic elastase, was prevented by an antibody (anti-S-GAL) and by competing with purified EBP or S-GAL peptide. Immunohistochemistry of adult aorta indicates that the EBP exists as a permanent component of mature elastic fibers. This observation, together with the in vitro studies, suggests that the EBP could protect insoluble elastin from extracellular proteolysis and contribute to the extraordinary stability of this protein. Double immunolabeling of fetal lamb aorta with anti-S-GAL and antitropoelastin antibodies demonstrated, under light and electron microscopy, intracellular colocalization of the proteins in smooth muscle cells (SMC). Incubation of SMC with galactosugars to dissociate tropoelastin from EBP caused intracellular aggregation of tropoelastin. A tropoelastin/EBP complex was extracted from SMC lysates by coimmunoprecipitation and cross-linking, and its functional significance was addressed by showing that its dissociation by galactosugars caused degradation of tropoelastin by endogenous serine proteinase(s). This suggests that the EBP may also serve as a "companion" to intracellular tropoelastin, protecting this highly hydrophobic protein from self-aggregation and proteolytic degradation.

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Samouillan, Valerie, Jany Dandurand, Laura Nasarre, Lina Badimon, Colette Lacabanne, and Vicenta Llorente-Cortés. "Conformation and Physical Structure of Tropoelastin from Human Vascular Cells: Influence of Cells Lipid Loading." Conference Papers in Science 2014 (May 12, 2014): 1–4. http://dx.doi.org/10.1155/2014/391242.

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Aggregated low density lipoproteins (agLDL) contribute to massive intracellular cholesteryl ester (CE) accumulation in human vascular smooth muscle cells (VSMC). Our aim was to determine the conformational and physical structure of agLDL and elastic material produced either by control human VSMC or by agLDL-loaded human VSMC (agLDL-VSMC). At the conformational level scanned by FTIR spectroscopy, a new undefined, probably non-H-bonded, structure for tropoelastin produced by agLDL-VSMC is revealed. By differential scanning calorimetry, a decrease of water affinity and a drop of the glass transition associated with aggregated tropoelastin (from 200°C to 159°C) in the supernatant from agLDL VSMC are evidenced. This second phenomenon is due to an interaction between agLDL and tropoelastin as detected by the weak specific FTIR absorption band of agLDL in supernatant from agLDL-loaded VSMC.

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Shipley, J. Michael, Robert P. Mecham, Erika Maus, Jeffrey Bonadio, Joel Rosenbloom, Ronald T. McCarthy, Mary L. Baumann, Cheryl Frankfater, Fernando Segade, and Steven D. Shapiro. "Developmental Expression of Latent Transforming Growth Factor β Binding Protein 2 and Its Requirement Early in Mouse Development." Molecular and Cellular Biology 20, no. 13 (July 1, 2000): 4879–87. http://dx.doi.org/10.1128/mcb.20.13.4879-4887.2000.

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ABSTRACT Latent transforming growth factor β (TGF-β) binding protein 2 (LTBP-2) is an integral component of elastin-containing microfibrils. We studied the expression of LTBP-2 in the developing mouse and rat by in situ hybridization, using tropoelastin expression as a marker of tissues participating in elastic fiber formation. LTBP-2 colocalized with tropoelastin within the perichondrium, lung, dermis, large arterial vessels, epicardium, pericardium, and heart valves at various stages of rodent embryonic development. Both LTBP-2 and tropoelastin expression were seen throughout the lung parenchyma and within the cortex of the spleen in the young adult mouse. In the testes, LTBP-2 expression was seen within lumenal cells of the epididymis in the absence of tropoelastin. Collectively, these results imply that LTBP-2 plays a structural role within elastic fibers in most cases. To investigate its importance in development, mice with a targeted disruption of the Ltbp2 gene were generated.Ltbp2 −/− mice die between embryonic day 3.5 (E3.5) and E6.5. LTBP-2 expression was not detected by in situ hybridization in E6.5 embryos but was detected in E3.5 blastocysts by reverse transcription-PCR. These results are not consistent with the phenotypes of TGF-β knockout mice or mice with knockouts of other elastic fiber proteins, implying that LTBP-2 performs a yet undiscovered function in early development, perhaps in implantation.

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Facharztmagazine, Redaktion. "Maßgeschneiderte Wundauflagen aus humanem Tropoelastin." Info Diabetologie 15, no. 4 (September 2021): 50. http://dx.doi.org/10.1007/s15034-021-3741-x.

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Tsuruga, E., K. Irie, Y. Sakakura, and T. Yajima. "Tropoelastin Expression by Periodontal Fibroblasts." Journal of Dental Research 81, no. 3 (March 1, 2002): 198–202. http://dx.doi.org/10.1177/154405910208100311.

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Tsuruga, E., K. Irie, Y. Sakakura, and T. Yajima. "Tropoelastin Expression by Periodontal Fibroblasts." Journal of Dental Research 81, no. 3 (March 2002): 198–202. http://dx.doi.org/10.1177/0810198.

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40

Kajiya, Hiroyoshi, Nobuhiko Tanaka, Toyoko Inazumi, Yoshiyuki Seyama, Shingo Tajima, and Akira Ishibashi. "Cultured Human Keratinocytes Express Tropoelastin." Journal of Investigative Dermatology 109, no. 5 (November 1997): 641–44. http://dx.doi.org/10.1111/1523-1747.ep12337639.

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41

Isnard, N., D. Thévenin, L. Robert, and G. Renard. "Tropoelastin Biosynthesis by Corneal Cells." Ophthalmologica 218, no. 1 (December 22, 2003): 36–42. http://dx.doi.org/10.1159/000074565.

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Parks, W. C., H. Secrist, L. C. Wu, and R. P. Mecham. "Developmental regulation of tropoelastin isoforms." Journal of Biological Chemistry 263, no. 9 (March 1988): 4416–23. http://dx.doi.org/10.1016/s0021-9258(18)68942-2.

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Rich, Celeste B., and Judith Ann Foster. "Characterization of rat heart tropoelastin." Archives of Biochemistry and Biophysics 268, no. 2 (February 1989): 551–58. http://dx.doi.org/10.1016/0003-9861(89)90322-6.

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Colombatti, A., A. Poletti, A. Carbone, D. Volpin, and G. M. Bressan. "Extracellular matrix of lymphoid tissues in the chick." Journal of Histochemistry & Cytochemistry 37, no. 5 (May 1989): 757–63. http://dx.doi.org/10.1177/37.5.2703709.

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We describe the immunohistochemical distribution of components of the extracellular matrix of the chick lymphoid system. In the thymus, basement membranes of epithelial cells bordering the lobules were intensely stained by laminin antibodies; fibronectin antibodies labeled the capsule and the septal matrix, and similar reactivity was seen with tropoelastin and gp 115 antibodies. No positivity was detected with any of the antibodies within the cortical parenchymal cells. Laminin was not detected in the medullary parenchyma, whereas fibronectin was present as coarse fibers. Tropoelastin and gp 115 appeared as a finer and more diffuse meshwork. In the bursa, laminin antibodies outlined the epithelial cells separating the cortex from the medulla. Fibronectin, tropoelastin, and gp 115 antibody stained the interfollicular septa and the cortical matrix, although to a different extent. Laminin was also detected in association with the interfollicular epithelium (IFE) basement membrane, whereas no staining was found underneath the follicle-associated epithelium (FAE). FAE cells not only lack a proper basement membrane but are also not separated from medullary lymphocytes by any of the other extracellular matrix components were investigated. Consequently, medullary lymphocytes are not sequestered, and can come easily into contact with antigens present in the intestinal lumen. All four antibodies stained the spleen capsule and spleen blood vessels, tropoelastin and gp 115 antibodies giving the strongest reactivity. A fine trabecular staining pattern was detected with gp 115 antibodies in the white pulp.

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Joyce, Belinda J., Megan J. Wallace, Richard A. Pierce, Richard Harding, and Stuart B. Hooper. "Sustained changes in lung expansion alter tropoelastin mRNA levels and elastin content in fetal sheep lungs." American Journal of Physiology-Lung Cellular and Molecular Physiology 284, no. 4 (April 1, 2003): L643—L649. http://dx.doi.org/10.1152/ajplung.00090.2002.

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Our objective was to determine the effects of sustained alterations in fetal lung expansion on pulmonary elastin synthesis. In fetal sheep, lung expansion was either decreased between 111 and 131 days' gestation (term ∼147 days) by tracheal drainage or increased for 2, 4, 7, or 10 days by tracheal obstruction, ending at 128 days' gestation. Lung tropoelastin mRNA levels were assessed by Northern blot analysis, total elastin content was measured biochemically, and staining of lung sections was used to assess the localization and form of elastic fibers. Tracheal obstruction significantly elevated pulmonary tropoelastin mRNA levels 2.5-fold at 2 days, but values were not different from controls at 4, 7, and 10 days; elastin content tended to be increased at all time points. A sustained decrease in lung expansion by tracheal drainage reduced pulmonary tropoelastin mRNA levels 2.5-fold; elastin content was also decreased compared with controls, and tissue localization was altered. Our results indicate that the degree of lung expansion in the fetus influences elastin synthesis, content, and tissue deposition.

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Mariani, Thomas J., Sarah E. Dunsmore, Qinglang Li, Xueming Ye, and Richard A. Pierce. "Regulation of lung fibroblast tropoelastin expression by alveolar epithelial cells." American Journal of Physiology-Lung Cellular and Molecular Physiology 274, no. 1 (January 1, 1998): L47—L57. http://dx.doi.org/10.1152/ajplung.1998.274.1.l47.

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Epithelial-mesenchymal interactions are of critical importance during tissue morphogenesis and repair. Although the cellular and molecular aspects of many of these interactions are beginning to be understood, the ability of epithelial cells to regulate fibroblast interstitial matrix production has not been extensively studied. We report here that cultured alveolar epithelial cells are capable of modulating the expression of tropoelastin, the soluble precursor of the interstitial lung matrix component elastin, by lung fibroblasts. Phorbol ester-stimulated alveolar epithelial cells secrete a soluble factor that causes a time- and dose-dependent repression of lung fibroblast tropoelastin mRNA expression. This alveolar epithelial cell-mediated repressive activity is specific for tropoelastin, is effective on lung fibroblasts from multiple stages of development, and acts at the level of transcription. Partial characterization of the repressive activity indicates it is an acid-stable, pepsin-labile protein. Gel fractionation of alveolar epithelial cell conditioned medium revealed two peaks of activity with relative molecular masses of ∼25 and 50 kDa. These data support a role for epithelial cells in the regulation of fibroblast interstitial matrix production.

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Tsuruga, E., K. Irie, and T. Yajima. "Gene Expression and Accumulation of Fibrillin-1, Fibrillin-2, and Tropoelastin in Cultured Periodontal Fibroblasts." Journal of Dental Research 81, no. 11 (November 2002): 771–75. http://dx.doi.org/10.1177/0810771.

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The elastic system fibers consist of three types—oxytalan, elaunin, and elastic fibers—differing in their relative microfibril and elastin contents. All three types are found in human gingiva, but human periodontal ligaments contain only elastin-free fibers. We examined cultured human gingival fibroblasts (HGF) and cultured human periodontal ligament fibroblasts (HPLF) to determine the gene expression of fibrillin-1 and fibrillin-2 (the major components of microfibrils) and of tropoelastin. In addition, we assessed the degree of accumulation of these proteins in the extracellular matrix. Northern blot analysis revealed that the level of expression of fibrillin-1 and fibrillin-2 was higher in HGF than in HPLF. However, examination of matrix samples from HGF and HPLF cell layers showed that there was no difference in fibrillin-1 accumulation, although fibrillin-2 accumulated to a much greater extent in the HGF-derived matrix. Tropoelastin was expressed only in and around HGF. These results show a correlation between gene expression and the accumulation of tropoelastin and fibrillin-2 in HGF.

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Lindahl, P., L. Karlsson, M. Hellstrom, S. Gebre-Medhin, K. Willetts, J. K. Heath, and C. Betsholtz. "Alveogenesis failure in PDGF-A-deficient mice is coupled to lack of distal spreading of alveolar smooth muscle cell progenitors during lung development." Development 124, no. 20 (October 15, 1997): 3943–53. http://dx.doi.org/10.1242/dev.124.20.3943.

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PDGF-A(−/−) mice lack lung alveolar smooth muscle cells (SMC), exhibit reduced deposition of elastin fibres in the lung parenchyma, and develop lung emphysema due to complete failure of alveogenesis. We have mapped the expression of PDGF-A, PDGF receptor-alpha, tropoelastin, smooth muscle alpha-actin and desmin in developing lungs from wild type and PDGF-A(−/−) mice of pre- and postnatal ages in order to get insight into the mechanisms of PDGF-A-induced alveolar SMC formation and elastin deposition. PDGF-A was expressed by developing lung epithelium. Clusters of PDGF-Ralpha-positive (PDGF-Ralpha+) mesenchymal cells occurred at the distal epithelial branches until embryonic day (E) 15.5. Between E16.5 and E17.5, PDGF-Ralpha+ cells multiplied and spread to acquire positions as solitary cells in the terminal sac walls, where they remained until the onset of alveogenesis. In PDGF-A(−/−) lungs PDGF-Ralpha+ cells failed to multiply and spread and instead remained in prospective bronchiolar walls. Three phases of tropoelastin expression were seen in the developing lung, each phase characterized by a distinct pattern of expression. The third phase, tropoelastin expression by developing alveolar SMC in conjunction with alveogenesis, was specifically and completely absent in PDGF-A(−/−) lungs. We propose that lung PDGF-Ralpha+ cells are progenitors of the tropoelastin-positive alveolar SMC. We also propose that postnatal alveogenesis failure in PDGF-A(−/−) mice is due to a prenatal block in the distal spreading of PDGF-Ralpha+ cells along the tubular lung epithelium during the canalicular stage of lung development.

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Vrhovski, Bernadette, Sacha Jensen, and Anthony S. Weiss. "Coacervation Characteristics of Recombinant Human Tropoelastin." European Journal of Biochemistry 250, no. 1 (November 15, 1997): 92–98. http://dx.doi.org/10.1111/j.1432-1033.1997.00092.x.

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Wise, Steven G., Giselle C. Yeo, Matti A. Hiob, Jelena Rnjak-Kovacina, David L. Kaplan, Martin K. C. Ng, and Anthony S. Weiss. "Tropoelastin: A versatile, bioactive assembly module." Acta Biomaterialia 10, no. 4 (April 2014): 1532–41. http://dx.doi.org/10.1016/j.actbio.2013.08.003.

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Journal articles on the topic 'Tropoelastin'

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