Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

During bone growth, development, and remodeling, angiogenesis as well as osteogenesis are closely associated processes, sharing some essential mediators. Vascular endothelial growth factor (VEGF) was initially recognized as the best-characterized endothelial-specific growth factor, which increased vascular permeability and angiogenesis, and it is now apparent that this cytokine regulates multiple biological functions in the endochondral ossification of mandibular condylar growth, as well as long bone formation. The complexity of VEGF biology is paralleled by the emerging complexity of interactions between VEGF ligands and their receptors. This narrative review summarizes the family of VEGF-related molecules, including 7 mammalian members, namely, VEGF, placenta growth factor (PLGF), and VEGF-B, -C, -D, -E, and -F. The biological functions of VEGF are mediated by at least 3 corresponding receptors: VEGFR-1/Flt-1, VEGFR-2/Flk-1, VEGFR-3/Flt-4 and 2 co-receptors of neuropilin (NRP) and heparan sulfate proteoglycans (HSPGs). Current findings on endochondral ossification are also discussed, with emphasis on VEGF-A action in osteoblasts, chondroblasts, and chondroclasts/osteoclasts and regulatory mechanisms involving oxygen tension, and some growth factors and hormones. Furthermore, the therapeutic implications of recombinant VEGF-A protein therapy and VEGF-A gene therapy are evaluated. Abbreviations used: VEGF, Vascular endothelial growth factor; PLGF, placenta growth factor; NRP, neuropilin; HSPGs, heparan sulfate proteoglycans; FGF, fibroblast growth factor; TGF, transforming growth factor; HGF, hepatocyte growth factor; TNF, tumor necrosis factor; ECM, extracellular matrix; RTKs, receptor tyrosine kinases; ERK, extracellular signal kinases; HIF, hypoxia-inducible factor.
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PMID:VEGF: an essential mediator of both angiogenesis and endochondral ossification. 1789 Jun 69

The differentiation of osteoblasts from mesenchymal precursors requires a series of cell fate decisions controlled by a hierarchy of transcription factors. Among these are RUNX2, Osterix (OSX), ATF4, and a large number of nuclear coregulators. During bone development, initial RUNX2 expression coincides with the formation of mesenchymal condensations well before the branching of chondrogenic and osteogenic lineages. Given that RUNX2 is expressed so early and participates in several stages of bone formation, it is not surprising that it is subject to a variety of controls. These include regulation by nuclear accessory factors and posttranslational modification, especially phosphorylation. Specific examples of RUNX2 regulation include interactions with DLX proteins and ATF4 and phosphorylation by the ERK/MAP kinase pathway. RUNX2 is regulated via phosphorylation of critical serine residues in the P/S/T domain. MAPK activation of RUNX2 was also found to occur in vivo. Transgenic expression of constitutively active MEK1 in osteoblasts accelerated skeletal development while a dominant-negative MEK1 retarded development in a RUNX2-dependent manner. These studies allow us to begin understanding the complex mechanisms necessary to fine-tune bone formation in response to extracellular stimuli including ECM interactions, mechanical loads, and hormonal stimulation.
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PMID:Transcriptional regulation of osteoblasts. 1808 28

Lung fibrosis involves the overexpression of ECM proteins, primarily collagen, by alpha-smooth muscle actin (ASMA)-positive cells. Caveolin-1 is a master regulator of collagen expression by cultured lung fibroblasts and of lung fibrosis in vivo. A peptide equivalent to the caveolin-1 scaffolding domain (CSD peptide) inhibits collagen and tenascin-C expression by normal lung fibroblasts (NLF) and fibroblasts from the fibrotic lungs of scleroderma patients (SLF). CSD peptide inhibits ASMA expression in SLF but not NLF. Similar inhibition of collagen, tenascin-C, and ASMA expression was also observed when caveolin-1 expression was upregulated using adenovirus. These observations suggest that the low caveolin-1 levels in SLF cause their overexpression of collagen, tenascin-C, and ASMA. In mechanistic studies, MEK, ERK, JNK, and Akt were hyperactivated in SLF, and CSD peptide inhibited their activation and altered their subcellular localization. These studies and experiments using kinase inhibitors suggest many differences between NLF and SLF in signaling cascades. To validate these data, we determined that the alterations in signaling molecule activation observed in SLF also occur in fibrotic lung tissue from scleroderma patients and in mice with bleomycin-induced lung fibrosis. Finally, we demonstrated that systemic administration of CSD peptide to bleomycin-treated mice blocks epithelial cell apoptosis, inflammatory cell infiltration, and changes in tissue morphology as well as signaling molecule activation and collagen, tenascin-C, and ASMA expression associated with lung fibrosis. CSD peptide may be a prototype for novel treatments for human lung fibrosis that act, in part, by inhibiting the expression of ASMA and ECM proteins.
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PMID:Antifibrotic properties of caveolin-1 scaffolding domain in vitro and in vivo. 1820 15

Sorsby fundus dystrophy (SFD) is an autosomal dominant macular degeneration of late onset. A key feature of the disease is the thickening of Bruch's membrane, an ECM structure located between the RPE and the choroid. SFD is caused by mutations in the gene encoding the ECM-associated tissue inhibitor of metalloproteases-3 (TIMP3). We have recently generated two Timp3 gene-targeted mouse lines, one deficient for the murine gene (Timp3-/-) and one carrying an SFD-related S156C mutation. Based on extracts and cell cultures derived from tissues of these animals we now evaluated TIMP3 functionality and its contribution to SFD. We show that the activity levels of TIMP3 target proteases including TACE, ADAMTS4/5 and aggrecan-cleaving MMPs are similar in Timp3S156/+ and Timp3S156C/S156C mice when compared to controls. In Timp3-/- mice, a significant enhancement of enzyme activity was observed for TACE but not for ADAMTS4/5 and MMPs indicating a compensatory effect of other inhibitors regulating the latter two groups of proteases. Fibrin bead assays show that angiogenesis in Timp3S156/+ and Timp3S156C/S156C mice is not altered whereas increased formation of capillary tubes was observed in Timp3-/- animals over controls. Rescue experiments using recombinant proteins demonstrate that the inhibitory activities of TIMP3 towards TACE and aggrecan-cleaving MMPs as well as the anti-angiogenic properties of TIMP3 are not impaired by SFD mutation S156C. We finally demonstrate that wild-type and S156C-TIMP3 proteins block the binding of VEGF to its receptor VEGFR2 to a similar extent. Taken together, this study shows that S156C-TIMP3 retains its known functional properties suggesting that causes other than an imbalance in protease or angiogenic activities represent the primary molecular defect underlying SFD.
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PMID:Molecular dissection of TIMP3 mutation S156C associated with Sorsby fundus dystrophy. 1857 11

We used microarray-based comparative genomic hybridization to explore genome-wide profiles of chromosomal aberrations in 26 samples of head and neck cancers compared to their pair-wise normal controls. The samples were obtained from Sudanese (n=11) and Norwegian (n=15) patients. The findings were correlated with clinicopathological variables. We identified the amplification of 41 common chromosomal regions (harboring 149 candidate genes) and the deletion of 22 (28 candidate genes). Predominant chromosomal alterations that were observed included high-level amplification at 1q21 (harboring the S100A gene family) and 11q22 (including several MMP family members). Regions of copy number increase was also identified at 6p21 (p21), 7p12 (EGFR), 17p13 (p53) and 19p13.2 (p19INK4d), while regions showing deletion included among others 3p25.2 (RAF1) and 9p21 (p15, p16). We found genes from four common biological pathways (MAPK signaling, cytokine-cytokine receptor interaction, ECM-receptor interaction and Jak-STAT signaling) to be predominantly over-represented in areas of gain and loss. The current study provides valuable information on chromosomal aberrations likely to be involved in the pathogenesis of head and neck cancers. An increased copy number of the S100A and MMP gene family members, known to be involved in invasion and metastasis, may play an important role in the development of the tumors. Hierarchical clustering of the chromosomal alterations with clinicopathological parameters showed little correlation, suggesting an occurrence of gains/losses regardless of ethnic differences and clinicopathological status between the patients from the two countries. Our findings indicate the existence of common gene-specific amplifications/deletions in these tumors, regardless of the source of the samples or attributed carcinogenic risk factors.
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PMID:Chromosomal aberrations in head and neck squamous cell carcinomas in Norwegian and Sudanese populations by array comparative genomic hybridization. 1881 24

The present in vitro study investigated the expression of basal lamina components by Schwann cells (SCs) cultivated on PCL and PLLA membranes prepared by solvent evaporation. Cultures of SCs were obtained from sciatic nerves from neonatal Sprague Dawley rats and seeded on 24 well culture plates containing the polymer membranes. The purity of the cultures was evaluated with a Schwann cell marker antibody (anti-S-100). After one week, the cultures were fixed and processed for immunocytochemistry by using antibodies against type IV collagen, laminin I and II. Positive labeling against the studied molecules was observed, indicating that such biomaterials positively stimulate Schwann cell adhesion and proliferation. Overall, the present results provide evidence that membrane-derived biodegradable polymers, particularly those derived from PLLA, are able to provide adequate substrate and stimulate SCs to produce ECM molecules, what may have in turn positive effects in vivo, influencing the peripheral nerve regeneration process.
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PMID:Expression of basal lamina components by Schwann cells cultured on poly(lactic acid) (PLLA) and poly(caprolactone) (PCL) membranes. 1898 57

Overexpression of plasminogen activator inhibitor-1 (SERPINE1, PAI-1), the major physiological inhibitor of pericellular plasmin generation, is a significant causative factor in the progression of vascular disorders (e.g. arteriosclerosis, thrombosis, perivascular fibrosis) as well as a biomarker and a predictor of cardiovascular-disease associated mortality. PAI-1 is a temporal/spatial regulator of pericellular proteolysis and ECM accumulation impacting, thereby, vascular remodeling, smooth muscle cell migration, proliferation and apoptosis. Within the specific context of TGF-beta1-initiated vascular fibrosis and neointima formation, PAI-1 is a member of the most prominently expressed subset of TGF-beta1-induced transcripts. Recent findings implicate EGFR/pp60c-src-->MEK/ERK1/2 and Rho/ROCK-->SMAD2/3 signaling in TGF-beta1-stimulated PAI-1 expression in vascular smooth muscle cells. The EGFR is a direct upstream regulator of MEK/ERK1/2 while Rho/ROCK modulate both the duration of SMAD2/3 phosphorylation and nuclear accumulation. E-box motifs (CACGTG) in the PE1/PE2 promoter regions of the human PAI-1 gene, moreover, are platforms for a MAP kinase-directed USF subtype switch (USF-1-->USF-2) in response to growth factor addition suggesting that the EGFR-->MEK/ERK axis impacts PAI-1 expression, at least partly, through USF-dependent transcriptional controls. This paper reviews recent data suggesting the essential cooperativity among the EGFR-->MAP kinase cascade, the Rho/ROCK pathway and SMADs in TGF-beta1-initiated PAI-1 expression. The continued clarification of mechanistic controls on PAI-1 transcription may lead to new targeted therapies and clinically-relevant options for the treatment of vascular diseases in which PAI-1 dysregulation is a major underlying pathogenic feature.
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PMID:Integration of non-SMAD and SMAD signaling in TGF-beta1-induced plasminogen activator inhibitor type-1 gene expression in vascular smooth muscle cells. 1913 20

Vascular smooth muscle cell (SMC) migration is an important mechanism in atherogenesis and postangioplasty arterial remodeling. Previously, we demonstrated that the proinflammatory cytokine interleukin (IL)-18 is a potent inducer of SMC migration. Since extracellular matrix metalloproteinase inducer (EMMPRIN) stimulates ECM degradation and facilitates cell migration, we investigated whether IL-18 and EMMPRIN regulate each other's expression, whether their cross talk induces SMC migration, and whether the phytoalexin resveratrol inhibits IL-18-EMMPRIN signaling and SMC migration. Our studies demonstrate that 1) IL-18 induces EMMPRIN mRNA and protein expressions and stimulates EMMPRIN secretion from human aortic SMCs; 2) IL-18 stimulates EMMPRIN expression via oxidative stress and phosphatidylinositol 3-kinase (PI3K)-Akt-ERK signaling; 3) IL-18-stimulated SMC migration is significantly blunted by EMMPRIN knockdown, EMMPRIN function-blocking antibodies, or adenoviral transduction of mutant EMMPRIN; 4) conversely, EMMPRIN stimulates IL-18 expression and secretion via PI3K, Akt, and ERK; and 5) resveratrol attenuates IL-18- and EMMPRIN-mediated PI3K, Akt, and ERK activations; blunts IL-18-mediated oxidative stress; blocks IL-18-EMMPRIN cross-regulation; and inhibits SMC migration. Collectively, our results demonstrate that the coexpression and regulation of IL-18 and EMMPRIN in the vessel wall may amplify the inflammatory cascade and promote atherosclerosis and remodeling. Resveratrol, via its antioxidant and anti-inflammatory properties, has the potential to inhibit the progression of atherosclerosis by blocking IL-18 and EMMPRIN cross-regulation and SMC migration.
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PMID:Resveratrol blocks interleukin-18-EMMPRIN cross-regulation and smooth muscle cell migration. 1956 11

Alpha-dystroglycan (alpha-DG) represents a highly glycosylated cell surface molecule that is expressed in the epithelial cell-basement membrane (BM) interface and plays an essential role in epithelium development and tissue organization. The alpha-DG-mediated epithelial cell-BM interaction is often impaired in invasive carcinomas, yet roles and underlying mechanisms of such an impaired interaction in tumor progression remain unclear. We report here a suppressor function of laminin-binding glycans on alpha-DG in tumor progression. In aggressive prostate and breast carcinoma cell lines, laminin-binding glycans are dramatically decreased, although the amount of alpha-DG and beta-dystroglycan is maintained. The decrease of laminin-binding glycans and consequent increased cell migration were associated with the decreased expression of beta3-N-acetylglucosaminyltransferase-1 (beta3GnT1). Forced expression of beta3GnT1 in aggressive cancer cells restored the laminin-binding glycans and decreased tumor formation. beta3GnT1 was found to be required for laminin-binding glycan synthesis through formation of a complex with LARGE, thus regulating the function of LARGE. Interaction of the laminin-binding glycans with laminin and other adhesive molecules in BM attenuates tumor cell migratory potential by antagonizing ERK/AKT phosphorylation induced by the components in the ECM. These results identify a previously undescribed role of carbohydrate-dependent cell-BM interaction in tumor suppression and its control by beta3GnT1 and LARGE.
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PMID:Tumor suppressor function of laminin-binding alpha-dystroglycan requires a distinct beta3-N-acetylglucosaminyltransferase. 1958 35

Matrix metalloproteinase-13 (MMP-13, or collagenase 3) has been shown to degrade intact collagen and to participate in situations where rapid and effective remodeling of collagenous ECM is required. Mechanical strain induction of MMP-13 is an example of how osteoblasts respond to high mechanical forces and participate in the bone-remodeling mechanism. Using MC3T3-E1 osteoblast-like cells, we dissected the signaling molecules involved in MMP-13 induction by mechanical strain. Reverse transcription-PCR and zymogram analysis showed that platelet-derived growth factor receptor (PDGFR) inhibitor, AG1296, inhibited the mechanical strain-induced MMP-13 gene and activity. However, the induction was not affected by anti-PDGF-AA serum. Immunoblot analysis revealed time-dependent phosphorylation of PDGFR-alpha up to 2.7-fold increases within 3 min under strain. Transfection with shPDGFR-alpha (at 4 and 8 microg/ml) abolished PDGFR-alpha and reduced MMP-13 expression. Moreover, time-dependent recruitments of phosphoinositide 3-kinase (PI3K) by PDGFR-alpha were detected by immunoprecipitation with anti-PDGFR-alpha serum followed by immunoblot with anti-PI3K serum. AG1296 inhibited PDGFR-alpha/PI3K aggregation and Akt phosphorylation. Interestingly, protein kinase C-delta (PKC-delta) inhibitor, rottlerin, inhibited not only PDGFR-alpha/PI3K aggregation but PDGFR-alpha phosphorylation. The sequential activations were further confirmed by mutants DeltaPKC-delta, DeltaAkt, and DeltaERK1. Consistently, the primary mouse osteoblast cells used the same identified signaling molecules to express MMP-13 under mechanical strain. These results demonstrate that, in osteoblast-like cells, the MMP-13 induction by mechanical strain requires the transactivation of PDGFR-alpha by PKC-delta and the cross-talk between PDGFR-alpha/PI3K/Akt and MEK/ERK pathways.
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PMID:Protein kinase C-delta transactivates platelet-derived growth factor receptor-alpha in mechanical strain-induced collagenase 3 (matrix metalloproteinase-13) expression by osteoblast-like cells. 1963 90


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