scholarly journals Mitogenic Activity and Signaling Mechanism of 2-(14,15- Epoxyeicosatrienoyl)Glycerol, a Novel Cytochrome P450 Arachidonate Metabolite

2007 ◽  
Vol 27 (8) ◽  
pp. 3023-3034 ◽  
Author(s):  
Jianchun Chen ◽  
Jian-Kang Chen ◽  
John R. Falck ◽  
Siddam Anjaiah ◽  
Jorge H. Capdevila ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Cytochrome P450 ◽  
Growth Factor ◽  
Transforming Growth Factor ◽  
Mitogenic Activity ◽  
Biologically Active ◽  
Cytochrome P450 Enzyme ◽  
Heparin Binding ◽  
Signaling Mechanism ◽  
Arachidonate Metabolite

ABSTRACT Arachidonic acid is an essential constituent of cell membranes that is esterified to the sn-2 position of glycerophospholipids and is released from selected phospholipid pools by tightly regulated phospholipase cleavage. Metabolism of the released arachidonic acid by the cytochrome P450 enzyme system (cP450) generates biologically active compounds, including epoxyeicosatrienoic acids (EETs) and hydroxyeicosatetraenoic acids. Here we report that 2-(14,15-epoxyeicosatrienoyl)glycerol (2-14,15-EG), a novel cP450 arachidonate metabolite produced in the kidney, is a potent mitogen for renal proximal tubule cells. This effect is mediated by activation of tumor necrosis factor alpha-converting enzyme (ADAM17), which cleaves membrane-bound transforming growth factor α (proTGF-α) and releases soluble TGF-α as a ligand that binds and activates epidermal growth factor receptor (EGFR). The present studies additionally demonstrate that the structurally related 14,15-EET stimulates release of soluble heparin-binding EGF-like growth factor as an EGFR ligand by activation of ADAM9, another member of the ADAM family. Thus, in addition to the characterization of 2-14,15-EG's mitogenic activity and signaling mechanism, our study provides the first example that two structurally related biologically active lipid mediators can activate different metalloproteinases and release different EGFR ligands in the same cell type to activate EGFR and stimulate cell proliferation.

The heparin-binding domain of amphiregulin necessitates the precursor pro-region for growth factor secretion

1994 ◽  
Vol 14 (3) ◽  
pp. 1635-1646
Author(s):  
B A Thorne ◽  
G D Plowman
Keyword(s):  
Growth Factor ◽  
Egf Receptor ◽  
Transforming Growth Factor ◽  
Binding Domain ◽  
Biologically Active ◽  
Structural Motif ◽  
Heparin Binding ◽  
Active Growth ◽  
Heparin Binding Domain ◽  
Pro Region

The five members of the human epidermal growth factor (EGF) family (EGF, transforming growth factor alpha [TGF-alpha], heparin-binding EGF-like growth factor [HB-EGF], betacellulin, and amphiregulin [AR]) are synthesized as transmembrane proteins whose extracellular domains are proteolytically processed to release the biologically active mature growth factors. These factors all activate the EGF receptor, but in contrast to EGF and TGF-alpha, the mature forms of HB-EGF and AR are also glycosylated, heparin-binding proteins. We have constructed a series of mutants to examine the influence of the distinct precursor domains in the biosynthesis of AR. The transmembrane and cytoplasmic domains of the precursor are not required for secretion of bioactive AR from either COS or mammary epithelium-derived cells, although proteolytic removal of the N-terminal pro-region is less efficient in the absence of the membrane anchor. Deletion of the N-terminal pro-region, however, results in rapid intracellular degradation of the molecule with no detectable secretion of active growth factor. AR secretion is preserved by replacing the native pro-region with the corresponding domain of the HB-EGF precursor but not with that of the TGF-alpha precursor. In the absence of any N-terminal pro-region, secretion of the molecule is restored by deleting the N-terminal heparin-binding domain of mature AR. Both EGF and TGF-alpha, in contrast, can be secreted without their pro-regions. However, if the protein is fused with the AR heparin-binding domain, TGF-alpha secretion is inhibited unless the AR pro-region is also present. We propose that the heparin-binding domain of mature AR necessitates the presence of a specific structural motif in an N-terminal pro-region to permit proper folding, and thus secretion, of a bioactive molecule.

scholarly journals Mitogenic Activity and Signaling Mechanism of 2-(14,15-Epoxyeicosatrienoyl)Glycerol, a Novel Cytochrome P450 Arachidonate Metabolite

2007 ◽  
Vol 27 (14) ◽  
pp. 5260-5260 ◽  
Author(s):  
Jianchun Chen ◽  
Jian-Kang Chen ◽  
John R. Falck ◽  
Jagadeesh Setti Guthi ◽  
Siddam Anjaiah ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Mitogenic Activity ◽  
Signaling Mechanism ◽  
Arachidonate Metabolite

scholarly journals The heparin-binding domain of amphiregulin necessitates the precursor pro-region for growth factor secretion.

1994 ◽  
Vol 14 (3) ◽  
pp. 1635-1646 ◽  
Author(s):  
B A Thorne ◽  
G D Plowman
Keyword(s):  
Growth Factor ◽  
Egf Receptor ◽  
Transforming Growth Factor ◽  
Binding Domain ◽  
Biologically Active ◽  
Structural Motif ◽  
Heparin Binding ◽  
Active Growth ◽  
Heparin Binding Domain ◽  
Pro Region

The five members of the human epidermal growth factor (EGF) family (EGF, transforming growth factor alpha [TGF-alpha], heparin-binding EGF-like growth factor [HB-EGF], betacellulin, and amphiregulin [AR]) are synthesized as transmembrane proteins whose extracellular domains are proteolytically processed to release the biologically active mature growth factors. These factors all activate the EGF receptor, but in contrast to EGF and TGF-alpha, the mature forms of HB-EGF and AR are also glycosylated, heparin-binding proteins. We have constructed a series of mutants to examine the influence of the distinct precursor domains in the biosynthesis of AR. The transmembrane and cytoplasmic domains of the precursor are not required for secretion of bioactive AR from either COS or mammary epithelium-derived cells, although proteolytic removal of the N-terminal pro-region is less efficient in the absence of the membrane anchor. Deletion of the N-terminal pro-region, however, results in rapid intracellular degradation of the molecule with no detectable secretion of active growth factor. AR secretion is preserved by replacing the native pro-region with the corresponding domain of the HB-EGF precursor but not with that of the TGF-alpha precursor. In the absence of any N-terminal pro-region, secretion of the molecule is restored by deleting the N-terminal heparin-binding domain of mature AR. Both EGF and TGF-alpha, in contrast, can be secreted without their pro-regions. However, if the protein is fused with the AR heparin-binding domain, TGF-alpha secretion is inhibited unless the AR pro-region is also present. We propose that the heparin-binding domain of mature AR necessitates the presence of a specific structural motif in an N-terminal pro-region to permit proper folding, and thus secretion, of a bioactive molecule.

scholarly journals Transforming growth factor alpha: mutation of aspartic acid 47 and leucine 48 results in different biological activities.

1988 ◽  
Vol 8 (3) ◽  
pp. 1247-1252 ◽  
Author(s):  
E Lazar ◽  
S Watanabe ◽  
S Dalton ◽  
M B Sporn
Keyword(s):  
Amino Acids ◽  
Biological Activity ◽  
Amino Acid ◽  
Growth Factor ◽  
Aspartic Acid ◽  
Transforming Growth Factor ◽  
Biologically Active ◽  
Single Amino Acid ◽  
Transforming Growth Factor Alpha ◽  
Factor Alpha

To study the relationship between the primary structure of transforming growth factor alpha (TGF-alpha) and some of its functional properties (competition with epidermal growth factor (EGF) for binding to the EGF receptor and induction of anchorage-independent growth), we introduced single amino acid mutations into the sequence for the fully processed, 50-amino-acid human TGF-alpha. The wild-type and mutant proteins were expressed in a vector by using a yeast alpha mating pheromone promoter. Mutations of two amino acids that are conserved in the family of the EGF-like peptides and are located in the carboxy-terminal part of TGF-alpha resulted in different biological effects. When aspartic acid 47 was mutated to alanine or asparagine, biological activity was retained; in contrast, substitutions of this residue with serine or glutamic acid generated mutants with reduced binding and colony-forming capacities. When leucine 48 was mutated to alanine, a complete loss of binding and colony-forming abilities resulted; mutation of leucine 48 to isoleucine or methionine resulted in very low activities. Our data suggest that these two adjacent conserved amino acids in positions 47 and 48 play different roles in defining the structure and/or biological activity of TGF-alpha and that the carboxy terminus of TGF-alpha is involved in interactions with cellular TGF-alpha receptors. The side chain of leucine 48 appears to be crucial either indirectly in determining the biologically active conformation of TGF-alpha or directly in the molecular recognition of TGF-alpha by its receptor.

scholarly journals Reduced EGFR signaling in progenitor cells of the adult subventricular zone attenuates oligodendrogenesis after demyelination

2007 ◽  
Vol 3 (3) ◽  
pp. 209-220 ◽  
Author(s):  
Adan Aguirre ◽  
Vittorio Gallo
Keyword(s):  
Growth Factor ◽  
Progenitor Cells ◽  
Subventricular Zone ◽  
Transforming Growth Factor ◽  
Mammalian Brain ◽  
Heparin Binding ◽  
Egfr Signaling ◽  
Transforming Growth Factor Α ◽  
Physiological Conditions ◽  
Focal Demyelination

AbstractNeural progenitor cells that express the NG2 proteoglycan are present in different regions of the adult mammalian brain where they display distinct morphologies and proliferative rates. In the developing postnatal and adult mouse, NG2+ cells represent a major cell population of the subventricular zone (SVZ). NG2+ cells divide in the anterior and lateral region of the SVZ, and are stimulated to proliferate and migrate out of the SVZ by focal demyelination of the corpus callosum (CC). Many NG2+ cells are labeled by GFP-retrovirus injection into the adult SVZ, demonstrating that NG2+ cells actively proliferate under physiological conditions and after demyelination. Under normal physiological conditions and after focal demyelination, proliferation of NG2+ cells is significantly attenuated in wa2 mice, which are characterized by reduced signaling of the epidermal growth factor receptor (EGFR). This results in reduced SVZ-to-lesion migration of NG2+ cells and oligodendrogenesis in the lesion. Expression of vascular endothelial growth factor (VEGF) and EGFR ligands, such as heparin binding-EGF and transforming growth factor α, is upregulated in the SVZ after focal demyelination of the CC. EGF-induced oligodendrogenesis and myelin protein expression in wild-type SVZ cells in culture are significantly attenuated in wa2 SVZ cells. Our results demonstrate that the response of NG2+ cells in the SVZ and their subsequent differentiation in CC after focal demyelination depend on EGFR signaling.

scholarly journals Transforming growth factor beta 1 (TGF-beta 1) induced neutrophil recruitment to synovial tissues: implications for TGF-beta-driven synovial inflammation and hyperplasia.

1991 ◽  
Vol 173 (5) ◽  
pp. 1121-1132 ◽  
Author(s):  
R A Fava ◽  
N J Olsen ◽  
A E Postlethwaite ◽  
K N Broadley ◽  
J M Davidson ◽  
...  
Keyword(s):  
Growth Factor ◽  
Synovial Tissue ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Biologically Active ◽  
Tgf Beta ◽  
Histological Techniques ◽  
Growth Factor Beta

We have studied the consequences of introducing human recombinant transforming growth factor beta 1 (hrTGF-beta 1) into synovial tissue of the rat, to begin to better understand the significance of the fact that biologically active TGF-beta is found in human arthritic synovial effusions. Within 4-6 h after the intra-articular injection of 1 microgram of hrTGF-beta 1 into rat knee joints, extensive recruitment of polymorphonuclear leukocytes (PMNs) was observed. Cytochemistry and high resolution histological techniques were used to quantitate the influx of PMNs, which peaked 6 h post-injection. In a Boyden chamber assay, hrTGF-beta 1 at 1-10 fg/ml elicited a chemotactic response from PMNs greater in magnitude than that evoked by FMLP, establishing that TGF-beta 1 is an effective chemotactic agent for PMNs in vitro as well as in vivo. That PMNs may represent an important source of TGF-beta in inflammatory infiltrates was strongly suggested by a demonstration that stored TGF-beta 1 was secreted during phorbol myristate acetate-stimulated degranulation in vitro. Acid/ethanol extracts of human PMNs assayed by ELISA contained an average of 355 ng of TGF/beta 1 per 10(9) cells potentially available for secretion during degranulation of PMNs. [3H]Thymidine incorporation in vivo and autoradiography of tissue sections revealed that widespread cell proliferation was triggered by TGF-beta 1 injection. Synovial lining cells and cells located deep within the subsynovial connective tissue were identified as sources of at least some of the new cells that contribute to TGF-beta 1-induced hyperplasia. Our results demonstrate that TGF-beta is capable of exerting pathogenic effects on synovial tissue and that PMNs may represent a significant source of the TGF-beta present in synovial effusions.

scholarly journals Extracellular Matrix and Cytokines: A Functional Unit

2000 ◽  
Vol 7 (2-4) ◽  
pp. 89-101 ◽  
Author(s):  
Elke Schönherr ◽  
Heinz-JüRgen Hausser
Keyword(s):  
Extracellular Matrix ◽  
Growth Factor ◽  
Heparan Sulfate ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Heparin Binding ◽  
Cytokine Network ◽  
Surface Receptors ◽  
Core Proteins ◽  
The Matrix

The extracellular matrix (ECM) as well as soluble mediators like cytokines can influence the behavior of cells in very distinct as well as cooperative ways. One group of ECM molecules which shows an especially broad cooperativety with cytokines and growth factors are the proteoglycans. Proteoglycans can interact with their core proteins as well as their glycosaminoglycan chains with cytokines. These interactions can modify the binding of cytokines to their cell surface receptors or they can lead to the storage of the soluble factors in the matrix. Proteoglycans themselves may even have cytokine activity. In this review we describe different proteoglycans and their interactions and relationships with cytokines and we discuss in more detail the extracellular regulation of the activity of transforming growth factor-β (TGF-β) by proteoglycans and other ECM molecules. In the third part the interaction of heparan sulfate chains with fibroblast growth factor-2 (FGF-2, basic FGF) as a prototype example for the interaction of heparin-binding cytokines with heparan sulfate proteoglycans is presented to illustrate the different levels of mutual dependence of the cytokine network and the ECM.

scholarly journals Periradicular Tissue Responses to Biologically Active Molecules or MTA When Applied in Furcal Perforation of Dogs' Teeth

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Anna Zairi ◽  
Theodoros Lambrianidis ◽  
Ourania Pantelidou ◽  
Serafim Papadimitriou ◽  
Dimitrios Tziafas
Keyword(s):  
Zinc Oxide ◽  
Growth Factors ◽  
Growth Factor ◽  
Transforming Growth Factor ◽  
Mineral Trioxide Aggregate ◽  
Biologically Active ◽  
Inflammatory Reactions ◽  
Zinc Oxide Eugenol ◽  
Tissue Responses ◽  
Igf I

The aim of this study was the comparative evaluation of inflammatory reactions and tissue responses to four growth factors, or mineral trioxide aggregate (MTA), or a zinc-oxide-eugenol-based cement (IRM) as controls, when used for the repair of furcal perforations in dogs’ teeth. Results showed significantly higher inflammatory cell response in the transforming growth factorβ1 (TGFβ1) and zinc-oxide-eugenol-based cement (IRM) groups and higher rates of epithelial proliferation in the TGFβ1, basic fibroblast growth factor (bFGF), and insulin growth factor-I (IGF-I) groups compared to the MTA. Significantly higher rates of bone formation were found in the control groups compared to the osteogenic protein-1 (OP-1). Significantly higher rates of cementum formation were observed in the IGF-I and bFGF groups compared to the IRM. None of the biologically active molecules can be suggested for repairing furcal perforations, despite the fact that growth factors exerted a clear stimulatory effect on cementum formation and inhibited collagen capsule formation. MTA exhibited better results than the growth factors.

174 EPIDERMAL GROWTH FACTORS AND CALBINDIN-D9k GENE EXPRESSIONS DURING PREGANCY IN THE PORCINE UTERUS

2008 ◽  
Vol 20 (1) ◽  
pp. 167
Author(s):  
Y.-J. Kim ◽  
E.-M. Jung ◽  
G.-S. Lee ◽  
S.-H. Hyun ◽  
E.-B. Jeung
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Transforming Growth Factor ◽  
Expression Patterns ◽  
Negative Control ◽  
Heparin Binding ◽  
Gene Expressions ◽  
Calbindin D9k ◽  
Genes Encoding ◽  
Epidermal Growth

To stably maintain pregnancy, several genes are expressed in the uterus. In particular, the endometrial expression of genes encoding growth factors appears to play a key role in maternal–fetal communication. Previous studies have characterized the endometrial expression kinetics of the genes encoding epidermal growth factor (EGF), its receptor (EGFR), transforming growth factor-alpha (TGF-α), amphiregulin (Areg), heparin-binding (Hb) EGF, and calbindin-D9k (CaBP-9k) in the pig during implantation. Here, we further characterized the expression patterns of these molecules during the entire porcine pregnancy. Porcine (n = 3 per PD) were collected at pregnancy days (PD) 12, 15, 30, 60, 90, and 110 and subjected to semi-quantitative RT-PCR. The data were analyzed with a nonparametric one-way analysis of variance using the Kruskal-Wallis test, followed by Dunnett's test for multiple comparisons to the negative control. EGF and EGFR showed similar expression patterns, being highly expressed around implantation time and then disappearing. TGF-α and Areg expression levels rose steadily until they peaked at PD30, after which they gradually decreased to PD12 levels. The Areg mRNA expression pattern was confirmed by real-time PCR, and similar Areg protein expression patterns were observed. Immunohistochemical analysis of PD60 uteri revealed Areg in the glandular and luminal epithelial cells. Hb-EGF was steadily expressed throughout the entire pregnancy while CaBP-9k was expressed strongly on PD12, and then declined sharply in PD15 before recovering slightly for the remainder of the pregnancy. Thus, the EGF family may play a key role during implantation in pigs. In addition, CaBP-9k may help maintain uterine quiescence during pregnancy by sequestering cytoplasmic Ca2+.

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