Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P51812 (mitogen-activated protein)
 10,636 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To understand the molecular alterations occurring during the aging process, we compared mitogen-activated protein (MAP) kinase activities in the intrinsically aged and photoaged skins in the same individuals. Furthermore, we investigated the molecular events related to MAP kinase changes in intrinsically aged and photoaged skins. We found that extracellular-signal-regulated kinase (ERK) activity in photoaged skin was reduced, and that the activities of c-Jun N-terminal kinase (JNK) and p38 kinase were increased compared with intrinsically aged skin in the same individuals. Phospho-c-Jun levels and activator protein 1 activities in photoaged skin were also higher than in intrinsically aged skin. Moreover, catalase activity was found to be much reduced in primary dermal fibroblasts from photoaged skin, and as a result, H2O2 accumulated more in primary dermal fibroblasts in photoaged skin. In addition, treating primary dermal fibroblasts from photoaged skin with catalase reduced H2O2 levels, reversed aging-dependent MAP kinase changes, and inhibited matrix metalloproteinase (MMP)-1 expression. Our results indicate that the accumulation of reactive oxygen species due to catalase attenuation may be a critical aspect of the MAP kinase signaling changes that may lead to skin aging and photoaging in human skin in vivo. Thus, the induction and regulation of endogenous antioxidant enzymes including catalase may offer a strategy for preventing and treating skin aging.
 ...
PMID:H2O2 accumulation by catalase reduction changes MAP kinase signaling in aged human skin in vivo. 1609 30

Regulation of the matrix metalloproteinases (MMPs) is crucial to regulate extracellular matrix (ECM) proteolysis which is important in metastasis. This study investigated the mechanism(s) by which three flavonoid-enriched fractions from lowbush blueberry (Vaccinium angustifolium) down-regulate MMP activity in DU145 human prostate cancer cells. Metalloproteinase activity was evaluated from cells exposed to "crude," anthocyanin-enriched (AN) and proanthocyanidin-enriched (PAC) fractions. Differential down-regulation of MMPs was observed. The activity of the endogenous tissue inhibitors of metalloproteinases (TIMPs) from these cells was also evaluated. Increases in TIMP-1 and TIMP-2 activity were observed in response to these fractions. The possible involvement of protein kinase C (PKC) and mitogen-activated protein (MAP) kinase pathways in the flavonoid-mediated decreases in MMP activity was observed. These findings indicate that blueberry flavonoids may use multiple mechanisms in down-regulating MMP activity in these cells.
 ...
PMID:Inhibition of matrix metalloproteinase activity in DU145 human prostate cancer cells by flavonoids from lowbush blueberry (Vaccinium angustifolium): possible roles for protein kinase C and mitogen-activated protein-kinase-mediated events. 1611 75

Adrenoceptors (ARs) are involved in the regulation of gonadotropin-releasing hormone (GnRH) release from native and immortalized hypothalamic (GT1-7) neurons. However, the AR-mediated signaling mechanisms and their functional significance in these cells are not known. Stimulation of GT1-7 cells with the alpha1-AR agonist, phenylephrine (Phe), causes phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) mitogen-activated protein (MAP) kinases that is mediated by protein kinase C (PKC)-dependent transactivation of the epidermal growth factor receptor (EGF-R). Phe stimulation causes shedding of the soluble ligand, heparin-binding EGF (HB-EGF), as a consequence of matrix metalloproteinase (MMP) activation. Phe-induced phosphorylation of the EGF-R, and subsequently of Shc and ERK1/2, was attenuated by inhibition of MMP or HB-EGF with the selective inhibitor, CRM197, or by a neutralizing antibody. In contrast, phosphorylation of the EGF-R, Shc and ERK1/2 by EGF and HB-EGF was independent of PKC and MMP activity. Moreover, inhibition of Src attenuated ERK1/2 responses by Phe, but not by HB-EGF and EGF, indicating that Src acts upstream of the EGF-R. Consistent with a potential role of reactive oxygen species (ROS), Phe-induced phosphorylation of EGF-R was attenuated by the antioxidant, N-acetylcysteine. These data suggest that activation of the alpha1-AR causes phosphorylation of ERK1/2 through activation of PKC, ROS and Src, and shedding of HB-EGF, which binds to and activates the EGF-R.
 ...
PMID:Role of metalloproteinase-dependent EGF receptor activation in alpha-adrenoceptor-stimulated MAP kinase phosphorylation in GT1-7 neurons. 1633 26

The ovarian hormone, 17beta-estradiol, has been suggested to play an important role in gender-specific differences in cardiovascular diseases. One possible cardioprotective mechanism involves the interaction between 17beta-estradiol and the renin-angiotensin system. Previous studies demonstrated that fibroblast function and gene expression are regulated by biochemical factors including growth factors, hormones, and cytokines, but little is known regarding the integration of these diverse signals. Therefore, the purpose of this study was to determine the ability of 17beta-estradiol to modulate angiotensin II (AngII) effects on integrin-induced collagen gel contraction, matrix metalloproteinase (MMP) activity and expression, and signal transduction pathways in isolated neonatal cardiac fibroblasts. 17beta-estradiol significantly attenuated AngII-stimulated collagen gel contraction and significantly diminished the effect of AngII on the expression of beta1 and not alpha1integrins. Active MMP-2 levels were decreased by AngII and addition of 17beta-estradiol resulted in further reductions. Relative MMP-2 mRNA levels showed essentially identical patterns to protein levels. 17beta-estradiol pretreatment increased AngII-mediated mitogen-activated protein (MAP) kinase p42/44 activation and slightly decreased p38 activation compared to non-pretreated fibroblasts. Simultaneous addition of 17beta-estradiol and AngII had little to no effect on AngII activation of p42/44 or p38 MAP kinase. The current studies demonstrate the inhibitory role of estrogen on AngII-induced fibroblast-mediated ECM remodeling, gene expression, and signal transduction. These studies begin to elucidate the mechanisms of estrogen effects on myocardial remodeling and function.
 ...
PMID:17beta-estradiol modulation of angiotensin II-stimulated response in cardiac fibroblasts. 1676 74

Genistein is a candidate cancer chemopreventive drug being tested in clinical trials. We have shown that genistein blocks prostate cancer (PCa) cell invasion, that p38 mitogen-activated protein (MAP) kinase regulates activation of matrix metalloproteinase type 2 (MMP-2) and cell invasion, and that genistein prevents transforming growth factor beta (TGFbeta) from activating p38 MAP kinase. More recently, we identified MAP kinase-activated protein kinase 2 (MAPKAPK2) and the 27-kDa heat shock protein (HSP27) as downstream regulators of p38 MAP kinase. However, MAPKAPK2 and HSP27 can be regulated by factors other than p38 MAP kinase, and HSP27 is up-regulated during PCa progression. The current study was undertaken to examine the role of MAPKAPK2 and HSP27 in modulating genistein-mediated regulation of PCa cell invasion. Genistein inhibited TGFbeta-mediated phosphorylation of MAPKAPK2 and HSP27. Inhibitory effects by genistein upon cell signaling, inhibition of MMP-2, and inhibition of invasion were retained when both PC3 and PC3-M cells were transfected with either wild-type MAPKAPK2 or HSP27. However, transfection with dominant-negative MAPKAPK2 or nonphosphorylatable mutant HSP27 led to decreases in cell invasion and to abrogation of responsiveness to either TGFbeta-mediated increases or genistein-mediated decreases in MMP-2 and cell invasion. It is noteworthy that, after transfection with constitutive active MAPKAPK2 or with pseudophosphorylated HSP27, levels of MMP-2 activation and cell invasion were high and overcame any inhibitory effect of genistein. These findings demonstrate that genistein-mediated inhibition of cell invasion rests upon blocking activation of the MAPKAPK2-HSP27 pathway, and that its activation during cancer progression has the potential to mitigate therapeutic efficacy.
 ...
PMID:Genistein inhibits matrix metalloproteinase type 2 activation and prostate cancer cell invasion by blocking the transforming growth factor beta-mediated activation of mitogen-activated protein kinase-activated protein kinase 2-27-kDa heat shock protein pathway. 1677 19

We hypothesize that environmental toxicants, such as polychlorinated biphenyl congeners, can activate vascular endothelial cells and thus increase formation of blood-borne metastases. This study indicates that exposure of human microvascular endothelial cells to 2,2',4,6,6'-pentachlorobiphenyl can stimulate transendothelial migration of tumor cells through up-regulation of matrix metalloproteinase (MMP)-3. In a series of experiments with specific small interfering RNA and pharmacologic inhibitors, we provide evidence that 2,2',4,6,6'-pentachlorobiphenyl can activate epidermal growth factor receptor (EGFR) and Janus kinase 3 (JAK3) in a closely coordinated and cross-dependent fashion. Activated EGFR and JAK3 stimulate in concert c-Jun NH(2)-terminal kinase and extracellular signal-regulated kinase 1/2 as well as increase DNA-binding activity of transcription factors activator protein-1 and polyomavirus enhancer activator protein 3, leading to transcriptional up-regulation of MMP-3 expression. These results indicate that the interplay among EGFR, JAK3, and mitogen-activated protein kinases, such as c-Jun NH(2)-terminal kinase and extracellular signal-regulated kinase 1/2, is critical for polychlorinated biphenyl-induced MMP-3 expression and accelerated transendothelial migration of tumor cells.
 ...
PMID:Interplay between epidermal growth factor receptor and Janus kinase 3 regulates polychlorinated biphenyl-induced matrix metalloproteinase-3 expression and transendothelial migration of tumor cells. 1677 83

Chronic obstructive pulmonary disease [COPD] is characterised by airflow limitation of peripheral airways that is not fully reversible and progressive and is associated with an abnormal inflammatory response of the lungs to noxious particles or gases. There is also intense airway wall remodelling and evidence of systemic inflammation. Increased interleukin [IL]-6, IL-1beta, tumor necrosis factor-alpha [TNF-alpha], GRO-alpha, MCP-1 and IL-8 levels are measured in sputum, with further increases during exacerbations. The bronchiolar epithelium over-expresses MCP-1, MIP-1alpha and IL-8. IL-8 can account for sputum neutrophil chemotactic activity. TNFalpha and IL-1beta stimulate macrophages to produce matrix metalloproteinase-9 [MMP-9], and bronchial epithelial cells to produce extracellular matrix glycoproteins. Increased expression of transforming growth factor-beta [TGFbeta) and epidermal growth factor [EGF] occurs in the epithelium and submucosal cells; gene array studies reveal an excess of TGFbeta1, CTGF and PDGFRA in COPD. TGFbeta and EGF activate proliferation of fibroblasts, while activation of the EGF receptor leads to mucin gene expression. Anti-cytokine therapy could be in the form of soluble receptors or by neutralising antibodies, small compounds blocking cytokine receptors or incomplete and non-activating cytokines, inhibitors of protein activation and inhibitors of signal transduction and transcription such as via inhibition of mitogen-activated protein kinases [MAPK] and of transcription factor, nuclear factor kappaB. Anti-IL-8 therapy has been tried with little effect on COPD, and current trials are on-going with TNF-alpha inhibitors. Other treatments such as phosphodiesterase 4 inhibitors have anti-cytokine effects that may underlie their beneficial effects in COPD.
 ...
PMID:Cytokines as targets in chronic obstructive pulmonary disease. 1678 67

Double-stranded RNA-dependent protein kinase (PKR), a ubiquitously expressed serine/threonine kinase, has been implicated in the regulation or modulation of cell growth through multiple signaling pathways, but how PKR regulates tumor necrosis factor (TNF)-induced signaling pathways is poorly understood. In the present study, we used fibroblasts derived from PKR gene-deleted mice to investigate the role of PKR in TNF-induced activation of nuclear factor-kappaB (NF-kappaB), mitogen-activated protein kinases (MAPKs) and growth modulation. We found that in wild-type mouse embryonic fibroblast (MEF), TNF induced NF-kappaB activation as measured by DNA binding but deletion of PKR abolished this activation. This inhibition was associated with suppression of inhibitory subunit of NF-kappaB (IkappaB)alpha kinase (IKK) activation, IkappaBalpha phosphorylation and degradation, p65 phosphorylation and nuclear translocation, and NF-kappaB-dependent reporter gene transcription. TNF-induced Akt activation needed for IKK activation was also abolished by deletion of PKR. NF-kappaB activation was diminished in PKR-deleted cells transfected with TNF receptor (TNFR) 1, TNFR-associated death domain and TRAF2 plasmids; NF-kappaB activated by NF-kappaB-inducing kinase, IKK or p65, however, was minimally affected. Among the MAPKs, it was interesting that whereas TNF-induced c-Jun N-terminal kinase (JNK) activation was abolished, activation of p44/p42 MAPK and p38 MAPK was potentiated in PKR-deleted cells. TNF induced the expression of NF-kappaB-regulated gene products cyclin D1, c-Myc, matrix metalloproteinase-9, survivin, X-linked inhibitor-of-apoptosis protein (IAP), IAP1, Bcl-x(L), A1/Bfl-1 and Fas-associated death domain protein-like IL-1beta-converting enzyme-inhibitory protein in wild-type MEF but not in PKR-/- cells. Similarly, TNF induced the proliferation of wild-type cells, but this proliferation was completely suppressed in PKR-deleted cells. Overall, our results indicate that PKR differentially regulates TNF signaling; IKK, Akt and JNK were positively regulated, whereas p44/p42 MAPK and p38 MAPK were negatively regulated.
 ...
PMID:Genetic deletion of PKR abrogates TNF-induced activation of IkappaBalpha kinase, JNK, Akt and cell proliferation but potentiates p44/p42 MAPK and p38 MAPK activation. 1692 32

Transforming growth factor beta 1 (TGF-beta1) is a potent tumor suppressor but, paradoxically, TGF-beta1 enhances tumor growth and metastasis in the late stages of cancer progression. This study investigated the role of TGF-beta type I receptor, ALK5, and three mitogen-activated protein kinases (MAPKs) in metastasis by breast cancer cell line MDA-MB-231. We show that autocrine TGF-beta signaling in MDA-MB-231 cells is required for tumor cell invasion and tumor angiogenesis. Expression of kinase-inactive ALK5 reduces tumor invasion and formation of new blood vessels within the tumor orthotopic xenografts in severe combined immunodeficiency (SCID) mice. In contrast, constitutively active ALK5-T204D enhances tumor invasion and angiogenesis by stimulating expression of matrix metalloproteinase MMP-9/gelatinase-B. Ablation of MMP-9 in ALK5-T204D cells by RNA interference (RNAi) reduces tumor invasion and tumor growth. Importantly, RNAi-MMP-9 reduces tumor neovasculature and increases tumor cell death. Induction of MMP-9 by TGF-beta-ALK5 signaling requires MEK-ERK but not JNK, p38 MAPK or Smad4. Dominant-negative MEK blocks and constitutively active MEK1 enhances MMP-9 expression. However, all three MAPK cascades (ERK, JNK and p38 MAPK) are required for TGF-beta-mediated cell migration. Collectively, our results show that TGF-beta-ALK5-MAPK signaling in tumor cells promotes tumor angiogenesis and MMP-9 is an important component of this program.
 ...
PMID:ALK5 promotes tumor angiogenesis by upregulating matrix metalloproteinase-9 in tumor cells. 1707 48

Cigarette smoking is a major risk factor for chronic obstructive pulmonary disease (COPD). Recent reports of increased matrix metalloproteinase-2 (MMP-2) in lungs of patients with emphysema support the paradigm of proteinase/antiproteinase imbalance in the pathogenesis of COPD. We sought to define the signaling pathways activated by smoke and to identify molecules responsible for emphysema-associated MMP-2 expression. In this study, we show that cigarette smoke extract (CSE) induced MMP-2 protein expression and increased MMP-2 gelatinase activity of normal lung fibroblasts. We previously identified a transcription factor, early growth response 1 (EGR-1), with robust expression in the lung tissues of patients with COPD compared with control smokers. Here, the treatment of fibroblasts with CSE resulted in marked induction of EGR-1 mRNA and protein in a dose- and time-dependent manner, accompanied by increased EGR-1 binding activity. CSE-induced MMP-2 mRNA and protein expression and activity were significantly inhibited using EGR-1 small interfering RNA (siRNA) or in Egr-1-null(-/-) mouse fibroblasts. Furthermore, we observed induction of membrane type 1 matrix metalloproteinase (MT1-MMP), which has an EGR-1-binding site on its promoter, in CSE-treated primary normal lung fibroblasts. The concomitant MT1-MMP expression and MMP-2 activation by CSE are inhibited by EGR-1 siRNA. Rapid activation of mitogen-activated protein kinases was observed in CSE-treated fibroblasts. Chemical inhibitors of ERK1/2 MAPK, but not of p38 and JNK, decreased CSE-induced EGR-1 protein expression and MMP-2 activity of fibroblasts. The identification that induction of MMP-2 and MT1-MMP by CSE from lung fibroblasts is EGR-1-dependent reveals a molecular mechanism for matrix remodeling in cigarette smoke-related emphysema.
 ...
PMID:Cigarette smoke stimulates matrix metalloproteinase-2 activity via EGR-1 in human lung fibroblasts. 1709 40


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>