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At least 73 records · Page 4Linked to original sources
PubMed2004

Expression of 67-kDa elastin receptor in annular elastolytic giant cell granuloma: elastin peptides induce monocyte-derived dendritic cells or macrophages to form granuloma in vitro.

Annular elastolytic giant cell granuloma (AEGCG) is characterized by non-palisading granuloma and elastophagocytic giant cells. Granulomas consist of structured masses of macrophages, dendritic cells, and T lymphocytes which play an essential role in granuloma formation. Two lineage systems of dendritic cells and macrophages originated from peripheral blood monocytes have been established in vitro. To know how elastin fragments are involved in the granuloma formation in AEGCG, we tested in vitro whether elastin fragments potentially induce monocyte-derived macrophages or dendritic cells to form granuloma and multinucleated giant cells. Immunohistochemical studies of the lesional skins of AEGCG (n = 5) revealed that the 67-kDa elastin receptor was specifically expressed in the epithelioid or multinucleated giant cells. Proliferation of factor XIIIa(+) cells and CD68(+) cells was also seen in the lesional skins of AEGCG. Factor XIIIa(+) dendritic cells or CD68(+) macrophages were established by the treatment of granulocyte/macrophage-colony stimulating factor (GM-CSF)/interleukin-4 or M-CSF, respectively. Further treatments of these dendritic cells or macrophages with elastin peptide resulted in the formation of granuloma or multinucleated giant cells which were immunoreactive with anti-67-kDa elastin receptor antibody. These findings suggest that elastic tissue induces factor XIIIa(+) cells and CD68(+) macrophages to form granuloma or multinucleated giant cells and plays an essential role in the formation of granuloma in AEGCG.

Aged↗
PubMed1984

Glucocorticoids stimulate elastin production in differentiated bovine ligament fibroblasts but do not induce elastin synthesis in undifferentiated cells.

Glucocorticoid treatment of fibroblasts from late gestation fetal bovine ligamentum nuchae resulted in a time- and dose-dependent selective increase in elastin production. Tropoelastin levels increased 2-3-fold in the presence of 10 nM dexamethasone while total protein synthesis and the rate of cell division decreased with glucocorticoid exposure. Two tropoelastin bands of molecular weights 64,500 and 61,000 were identified by immunoprecipitation and sodium dodecyl sulfate gradient-gel electrophoresis and both bands increased to an equal extent in the presence of dexamethasone. Undifferentiated cells from early-gestation animals did not synthesize elastin after hormone exposure, even though glucocorticoid receptors were demonstrated by nuclear-translocation experiments. These results indicate that glucocorticoids stimulate elastin production in elastin-producing ligament cells but do not induce elastin synthesis (differentiation) in undifferentiated cells.

Animals↗
PubMed1982

Analysis of elastin gene expression in the developing chick aorta using cloned elastin cDNA.

A segment of chick elastin cDNA cloned in the plasmid pBR322 was sequenced by the method of Maxam and Gilbert ((1977) Proc. Natl. Acad. Sci. U. S. A. 74, 560-564) and the 192-base pair insert was found to be derived from the nontranslated region of the 3' end of the mRNA. The nick-translated cDNA was used to identify and to estimate the relative amounts of elastin mRNA in the developing chick embryo aorta by blot hybridization. A single species of 3.5 kilobases hybridized to the cDNA probe and this species increased greatly between day 7 and day 14 of embryonic development. This increase was paralleled by an increase in translatable aortic elastin mRNA and by the in vivo rate of elastin synthesis, demonstrating that the change in synthesis during development is largely controlled by the elastin mRNA content of the aorta.

Animals↗
PubMed1989

Structure of the elastin gene and alternative splicing of elastin mRNA: implications for human disease.

The protein elastin is largely responsible for the elastic properties of vertebrate lungs, large blood vessels, and skin. The structure of the human, bovine, and chick elastin gene and protein monomer, tropoelastin, has recently been elucidated by using techniques of molecular biology. Extensive homology of amino acid sequence exists among the mammalian species and there is in addition strong conservation of nucleotide sequences in the 3' untranslated region of the gene. The translated exons are small and embedded in large expanses of introns. Sequences coding for the hydrophobic regions, responsible for the elastic properties of the molecule, and the alanine-lysine rich regions, responsible for crosslink formation between molecules, reside in separate exons and alternate for the most part in the elastin gene. S1 analyses and sequence analysis of cDNA and genomic clones have indicated that there is substantial alternative splicing of the primary elastin transcript. Variations in the structure of mRNAs resulting from alternative splicing could explain the existence of the multiple forms of tropoelastin observed electrophoretically in several species. Different kinds of splicing patterns could occur in human populations and may contribute to aging and pathological situations in the cardiovascular and pulmonary systems.

Aging↗
PubMed1986

Elastin in the human intervertebral disk. A histological and biochemical study comparing it with elastin in the human yellow ligament.

The elastic fiber and elastin in the human yellow ligament and intervertebral disk were studied histologically and biochemically. The elastic fiber in the human intervertebral disk, which until now had not been clearly identified microscopically, was observed clearly. We found the distribution of the elastic fiber in the intervertebral disk to be very sparse and irregular, and its diameter was small, being about one-tenth of that found in the yellow ligament. The elastin contents of the yellow ligament and intervertebral disk were 46.7% +/- 0.9% and 1.7% +/- 0.2% respectively (mean +/- SE) of the total dry weight. The amino acid composition of elastin in the yellow ligament is similar to that of other tissue, as reported in the literature; however, that found in the intervertebral disk is significantly different. It would appear, therefore, that the elastin in the intervertebral disk is of a different type from that found elsewhere.

Adolescent↗
PubMed1980

Translation of chick aortic elastin messenger ribonucleic acid. Comparison to elastin synthesis in chick aorta organ culture.

Studies were undertaken to define the molecular size of the elastin primary gene product. Translation of chick aortic messenger ribonucleic acid (mRNA) in an mRNA-dependent reticulocyte lysate resulted in the synthesis of two major proteins of 70 000 and 73 000 molecular weights. Both proteins were shown to be soluble forms of elastin by isotope incorporation, immunoprecipitation, collagenase and cyanogen bromide sensitivity, and two-dimensional gel electrophoresis. The 70 000-dalton protein behaves similarly to authentic tropoeleastin in sodium dodecyl sulfate gel electrophoresis. There was no evidence for a high molecular weight form of soluble elastin, although procollagen chains were indirectly identified among the aortic mRNA-directed translation products. The same molecular size proteins were also seen in organ cultures of chick embryonic aortas labeled with [3H]valine. However, the 73 000-dalton protein was not extractable in a neutral salt buffer but was found only if the aortas were extracted with urea in the presence of reducing and alkylating reagents. The results from these studies suggest that elastin is first synthesized as two distinct polypeptide chains which differ slightly in size and overall charge. The possibility that these two proteins may associate posttranslationally to form a dimer prior to secretion is postulated to explain the existence of a putative proelastin molecule seen in other systems.

Animals↗
PubMed2004

Elastin-derived peptides upregulate matrix metalloproteinase-2-mediated melanoma cell invasion through elastin-binding protein.

Type I collagen mediates melanoma cells invasion through upregulation of matrix metalloproteinases-1 and -2 (MMP-1 and -2) expression and activation. We investigated here the contribution of elastin-derived peptides (ED), degradation products of elastin, the main component of elastic fibers in melanoma cells invasion and MMP-1 and -2 expression. Our results evidenced fragmentation of elastin at the invasive front of melanoma, particularly in the most invasive tumors where those fibers nearly totally vanished. By electron microscopy, elastolysis was found to occur mainly at the periphery of melanoma cells, where close contact between elastic fibers and cells could be noticed. Therefore, we showed in vitro that plating melanoma cells high tumorigenic potential on ED-coated dishes, selectively enhanced MMP-2, as membrane-type MMP-1 (MT1-MMP) production and activation. Nevertheless, pro-MMP-2 activation was not observed owing to the parallel increase in tissue inhibitor of metalloproteinase (TIMP)-2 expression. The effects of ED on melanoma cells were found to be mediated by splicing form of beta-galactosidase (S-Gal) occupancy, as being suppressed by lactose. Supplementing collagen lattices with ED led to consistent activation of MMP-2 that can be attributed to TIMP-2 downregulation. Upregulation of MMP-2 activation by ED led to enhanced melanoma cells invasion through S-Gal occupancy. Immunohistochemistry studies, confirmed that S-Gal expression was more prominent at the melanoma invasion site associated with a strong expression of MMP-2 and MT1-MMP. We hypothesize that ED following interactions with S-Gal elastin receptor can favor melanoma cells invasion through a three-dimensional type I collagen matrix by upregulating MMP-2 activation.

Cell Division↗
PubMed2002

Monocyte chemotactic activity in human abdominal aortic aneurysms: role of elastin degradation peptides and the 67-kD cell surface elastin receptor.

BACKGROUND: Chronic inflammation is a characteristic feature of abdominal aortic aneurysms (AAAs), but the molecular signals responsible for recruiting monocytes into the outer aortic wall are unresolved. The purpose of this study was to examine whether AAA tissues elaborate chemotactic activity for mononuclear phagocytes and to determine whether this activity is attributable to interactions between elastin degradation peptides (EDPs) and their cell surface receptor, the 67-kD elastin binding protein (EBP). MATERIAL AND METHODS: Soluble proteins were extracted from human AAA tissues, and chemotactic activity for differentiated U937 mononuclear phagocytes was measured by use of a modified Boyden chamber. Chemotactic activity induced by N -formyl-Met-Leu-Phe was used as a positive control and checkerboard analysis was used to distinguish chemotaxis from chemokinesis. Inhibition of chemotaxis was tested by peptide competition, blocking antibodies and galactosugar-mediated dissociation of the 67-kD EBP. RESULTS: AAA extracts stimulated a concentration-dependent increase in monocyte migration that reached up to 24% of the maximal effect induced by N -formyl-Met-Leu-Phe. Checkerboard analysis demonstrated that AAA extracts stimulated chemotaxis without a chemokinetic effect. AAA-derived chemotactic activity was eliminated by competition with Val-Gly-Val-Arg-Pro-Gly (VGVAPG), a repetitive peptide found in human elastin that binds to cellular elastin receptors, and decreased nearly 40% in the presence of BA-4, an antielastin monoclonal antibody that can block EDP-mediated chemotactic activity. Monocyte chemotaxis in response to both VGVAPG and AAA extracts was abolished in the presence of lactose, a galactosugar that specifically dissociates the 67-kD EBP, but it was unaffected by either glucose, fructose, or mannose. CONCLUSIONS: These findings indicate that soluble EDPs released within human AAA tissue can subsequently attract mononuclear phagocytes through ligand-receptor interactions with the 67-kD EBP, thereby providing a plausible molecular mechanism to explain the inflammatory response that accompanies aneurysmal degeneration. Better understanding of factors regulating inflammatory cell recruitment may lead to novel forms of therapy for early stages of aneurysmal degeneration.

Antibodies↗
PubMed1983

In vitro translation of elastin mRNA and processing of the translated products and the signal sequence of elastin a.

Chick embryo aorta mRNAs were translated in a gel-filtered reticulocyte lysate. The translated products showed two elastin-related proteins (a and b; relative mass approximately 70 000). The translated elastin a protein was separated essentially free of the b protein by centrifugation and sodium dodecyl sulfate (SDS) - polyacrylamide gel electrophoresis. The a protein was then electroeluted from the SDS-polyacrylamide gel and a partial sequence was determined by automated Edman degradation. The NH2-terminal presequence of the elastin a protein is (formula; see text) The assigned sequence is identical to that reported for the b protein. Translation of chick embryo aorta mRNA in the presence of dog pancreas microsomal membranes segregated the a and b proteins into membrane vesicles and cotranslationally cleaved their respective presequences. The processed a and b elastin proteins were isolated together and NH2-terminal proline positions were determined. These are (formula; see text) These proline positions 4 and 8 are identical to those for NH2-terminal sequence for tropoelastin. This suggests that the signal peptidase removes the 24-residue signal peptide and thus directly generates the tropoelastin sequence, with no NH2-terminal prosequence as the intermediate.

Amino Acid Sequence↗
PubMedDate not supplied

Partial characterization of bovine elastin gene; comparison with the gene for human elastin.

A 14 kilobase (kb) genomic clone of the gene for bovine elastin, containing exons 1 and 2, has been characterized. This clone extends about 6.5 kb in the 5' direction from the initiation codon and 978 nucleotides in the 3' direction from exon 2. The size of the first intron is about 6.4 kb. The sequence immediately 5' to the initiation codon is highly conserved between the genes for bovine and human elastins and contains a TATA box consensus sequence (ATAAA), CAAT, and Sp1 binding sites. Several putative AP-2 binding sites are also present. Comparative analysis of the sequences flanking the first exon in the genes for bovine and human elastins identified conserved sequences that may be regulatory control elements. A putative enhancer core sequence is present in the first intron of the genes for bovine and human elastins.

Animals↗
PubMed1999

Elastic nevus with normal expression of elastin and elastin-related proteins mRNAs.

A 3-year-old Japanese girl presented with disseminated white papules on the trunk. A biopsied specimen of the lesional skin revealed a focal accumulation of elastic fibers in the mid to deep dermis. No skeletal involvement was detected. This case was considered to be elastic nevus without systemic involvement. Since an elevated elastin expression in the fibroblasts of typical Buschke-Ollendorff syndrome (BOS) has been reported, elastin and elastin-related protein mRNA levels in the cultured patient fibroblasts were determined. There were no significant differences of steady-state levels of elastin, fibrillin 1 and microfibril-associated glycoprotein 1 mRNAs between patient and matched control fibroblasts. Elastic nevus without skeletal involvement may be etiologically different from typical BOS.

Blotting, Northern↗
PubMed1975

Elastin--proteoglycan interaction. Conformational changes of alpha-elastin induced by the interaction.

The interaction between alpha-elastin and a connective tissue proteoglycan was followed by optical density measurements and circular dichroism spectroscopy. It was found that interaction takes place at pH values below the isoelectric point of elastin with the formation of a complex coacervate. CD spectra demonstrated conformational changes of alpha-elastin caused by the interaction and resulting in an increase in the content of helical structure. This finding suggests the possibility of the involvement of proteoglycans in the molecular organization of elastin.

Circular Dichroism↗
PubMed1981

Guanidination of the lysine residues present in fibrous elastin and in soluble elastin peptides.

We have found that only 20 to 30% of the lysine residues measured after acid hydrolysis of insoluble elastin and alpha-elastin were blocked by prior guanidination of elastin with o-methylisourea. In contrast free lysine was guanidinated almost 100% and a purified, highly crosslinked peptide fraction of low molecular weight, 85%. The non-reactivity of lysine does not seem to be due to steric hindrance in the fibrous protein or in the large peptides derived therefrom but rather to the presence of epsilon [delta-adipic acid]-lysine, the oxidized form of lysinonorleucine described by Bailey et al. Since photolysis of desmosine and isodesmosine leads also to the formation of new lysine residues, methods will have to be devised to distinguish lysine-containing peptides derived from photolyzed elastin.

Amino Acids↗
PubMed1977

The presence of fine elastin fibrils within the elastin fibre observed by scanning electron microscopy.

Scanning electron microscopy of critical point dried, enzymically and chemically purified fetal and adult elastin fibres from bovine ligamentum nuchae has shown that the fibres are composed of fine elastin fibrils (110-130nm diameter). In the fetal tissue the elastin fibres were of relatively uniform thickness and did not bifurcate, but in the adult, much thicker, branching fibres were present. It would appear that, during maturation of the elastin fibre, thickening is the result of the aggregation of many fine fibrils, and bifurcations result form bundles of such fibrils crossing over from one fibre to another.

Animals↗
PubMed1976

Calcification of alpha-elastin coacervates: a bulk property of elastin.

Scanning electron microscopy and electron probe microanalysis studies are reported on thin sections of calcified coacervates of alpha-elastin. It is found that the capacity of elastin coacervates to initiate calcification is a bulk property of the coacervate and not limited to the serum-coacervate interface, that the calcium phosphate deposits act to bind the protein units together and slow the dissolution and spreading of the coacervate as it floats on an airwater interface, and that, within the limits of detectability, there is no involvement of sulfur. As the charged groups of alpha-elastin had been blocked, the initiation of deposition is due to neutral sites in the protein which are tightly bound to the calcium phosphate deposits.

Animals↗
PubMed1981

Amino acid analysis of elastin hydrolysates using a lithium citrate gradient: quantification of elastin from whole lung.

A method to quantitate the elastin content in lungs is described. Desmosine and isodesmosine, the cross-linking amino acids unique to elastin, were measured directly from acid hydrolysates of hamster and human lungs by amino acid analysis. A Durrum D-500 (Dionex) amino acid analyzer, with a modified lithium citrate buffer gradient was used. Results compared favorably with those obtained by gravimetric and microenzymatic techniques, and the method described could be used for the quantification of elastin in biopsy specimens

Amino Acids↗
PubMed1993

Elastin peptide concentration in human serum: variation with antibodies and elastin peptides used for the enzyme-linked immunosorbent assay.

Discrepancies exist between the reported values for the mean elastin peptide (EP) concentration in human sera. In order to understand these discrepancies, several EP preparations were obtained in vitro and monoclonal and polyclonal antibodies were produced against them. These different EP preparations and antibodies were used in an enzyme-linked immunosorbent assay (ELISA) to study cross-reactivity between EP preparations and to quantitate EP concentration in human sera. The method of purification of elastin, the method of hydrolysis of elastin and the molecular weight of EP influence their reactivity with antibodies and the results of EP measurements in human sera. However, there is a good correlation between EP measurements carried out in several human sera with the different EP preparations and different antibodies. Although absolute values of the EP concentrations varied with the EP preparation and antibodies used for the ELISA, the variations of this EP concentration measured from one human serum to another are significant.

Antibodies, Monoclonal↗