Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.24 (mitogen-activated protein kinase)
 95,810 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Intermedin (IMD) is a newly discovered peptide closely related to adrenomedullin. We recently reported that IMD gene delivery prevented kidney damage and capillary loss in a rat model of chronic renal injury. In this study, we evaluated the role of IMD in angiogenesis in the ischemic hindlimb. Adenovirus containing human IMD or control adenovirus (Ad.Null) was injected into the adductor muscles of rats immediately after femoral artery ligation. The expression of human IMD was detected in the skeletal muscle 5 days after the viral injection. Blood perfusion in the ischemic hindlimb was monitored by laser-Doppler imaging from 1 to 3 wk after gene delivery. When compared with animals receiving Ad.Null, those with IMD gene transfer resulted in a time-dependent increase in blood perfusion. IMD gene delivery also increased capillary and arteriole density in ischemic hindlimb, identified by anti-CD-31 and alpha-smooth muscle actin immunostaining. Angiogenesis promoted by IMD was confirmed by increased capillary formation and hemoglobin content in Matrigel implants containing IMD peptide in mice. In cultured endothelial cells, IMD induced cell migration and tube formation, and these effects were blocked by the inhibition of extracellular signal-regulated kinase (ERK), Akt, nitric oxide (NO) synthase (NOS), vascular endothelial growth factor receptor-2 (VEGFR-2), and anti-IMD-neutralizing antibody. IMD was found to increase the phosphorylation of ERK, Akt, and endothelial NOS, as well as to augment NO formation, VEGF, and VEGFR-2 synthesis. Taken together, these results indicate that IMD enhances angiogenesis through ERK, Akt/NOS/NO, and VEGF/VEGFR-2 signaling pathways and raises the potential of IMD gene or peptide administration in the modulation of endothelial dysfunction.
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PMID:Intermedin is a new angiogenic growth factor. 1959 12

The serotonin transporter (SERT) gene has been proposed as a candidate gene responsible for the sudden infant death syndrome (SIDS). In this study, for the first time we obtained a SERT-knockout (KO) mouse model which reproduces SIDS phenotype. SERT-KO mice were generated by mating SERT(Cre/+) heterozygous mice. The SERT-KO mouse embryos at the pre-natal stage E18.5 were lacking of SERT mRNA and protein expression in the heart. A premature death of 75% of SERT-KO mice occurred in the first week after birth. LacZ staining of whole mounts and tissue sections of the heart from SERT(Cre/+);ROSA26R adult mice and E18.5 embryos demonstrated a marked localized expression of SERT in the right ventricle, the conal region, the vasculature, the atrial septum, the ventricular valves, and the sinoatrial node of the conduction system. These data suggest a cardiac phenotype for the sudden death of SERT-KO mice. Histological analysis of heart sections showed that SERT-KO mice develop cardiac fibrosis. Increased collagen accumulation in the myocardium and the valvular and perivascular regions, and enhanced expression of alpha-smooth muscle actin were detected in the heart of SERT-KO mice versus wild-type (WT) mice. Interestingly, higher expression levels of the 5-HT2A receptor and increased levels of phospho-SMAD2/3 and phospho-ERK1/2 were detected in SERT-KO mouse heart versus WT mice. Overall, our findings provide i) new insights into the role of SERT gene in SIDS, and ii) the first in vivo validation of the molecular mechanism involving the activation of TGF-beta1 signalling in the cardiac fibrosis.
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PMID:Serotonin transporter gene deficiency is associated with sudden death of newborn mice through activation of TGF-beta1 signalling. 1964 88

Significant reduction of renal mass initiates a series of hemodynamic and nonhemodynamic events which lead to proteinuria, glomerulosclerosis, tubulointerstitial injury, and end-stage renal failure. Lipid mediators derived from fatty acids participate in regulation of renal hemodynamic and nonhemodynamic processes that influence progression of renal disease. Composition of cellular fatty acids and hence related signaling responses are influenced by their dietary contents. Consumption of omega-3 fatty acids (O-3FA) has proven effective in mitigating atherosclerosis. We tested the hypothesis that O-3FA supplementation may retard progression and attenuate upregulation of pathways involved in oxidative stress, inflammation, and fibrosis in rats with renal mass reduction. Sprague-Dawley rats were subjected to 5/6 nephrectomy [chronic renal failure (CRF)] and randomly assigned to the untreated and O-3FA-treated (0.3 g.kg(-1).day(-1) by gastric gavage for 12 wk) groups. Sham-operated rats served as controls. The untreated CRF rats exhibited proteinuria, hypertension, azotemia, upregulations of renal tissue NAD(P)H oxidase, MCP-1, COX-2, PAI-1, TGF-beta, Smad2, alpha-smooth muscle actin, fibronectin, and hepatocyte growth factor, activation of ERK1/2 and NF-kappaB, downregulation of Smad7, intense mononuclear leukocyte infiltration, tubulointerstitial fibrosis, and glomerulosclerosis. O-3FA supplementation significantly lowered COX-2, NAD(P)H oxidase (NOX-4, gp91(phox), p47(phox), p22(phox)), PAI-1, TGF-beta, connective tissue growth factor, alpha-smooth muscle actin, fibronectin, Smad2, and MCP-1, raised Smad7, and attenuated ERK1/2 and NF-kappaB activation, tubulointerstitial fibrosis, and inflammation. Thus, long-term O-3FA supplementation can reduce or reverse upregulation of prooxidant, proinflammatory, and profibrotic pathways and attenuate tubulointerstitial fibrosis in the remnant kidney.
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PMID:Omega-3 fatty acid supplementation attenuates oxidative stress, inflammation, and tubulointerstitial fibrosis in the remnant kidney. 1965 15

Fibrosis is the response of heart and other organs to injuries. Excessive fibrosis can cause organ dysfunction or even failure. Transforming-growth factor (TGF)-beta is a cytokine that induces fibroblast proliferation and increases the synthesis of a number of extracellular matrix proteins including collagens. Decorin (DCN) is a natural antagonist of TGF-beta. In the current study, we investigated the potential antifibrotic effects of DCN gene delivery by a recombinant adeno-associated viral (rAAV) vector to inhibit cardiac fibrosis in old, spontaneously hypertensive rats (SHRs), which develop severe cardiac and kidney fibrosis if without intervention. The rAAV-DCN vector was injected (at a dose of 1 x 10(11) vector genomes) via the tail vein into 5-month-old male SHRs, resulting in persistent, stable expression of DCN (up to 16 weeks). rAAV-DCN treatment significantly reduced collagen content and fibrosis in the heart and attenuated cardiomyocyte hypertrophy. Hemodynamics data at 16 weeks showed that DCN gene delivery induced a significant increase in left ventricular end-systolic pressure and maximal-minimal rate of pressure increase (+/-dp/dt(max)), but a decrease in left ventricular end-diastolic pressure (p < 0.05), compared with those of control animals. The expression of TGF-beta and alpha-smooth muscle actin, and the phosphorylation levels of Smad2 and p38 MAPK, were markedly reduced by rAAV-DCN treatment as compared with the controls. Thus, these results suggest that rAAV-mediated DCN overexpression led to the inhibition of hypertension-induced cardiac fibrosis and hypertrophy and improved cardiac function, and therefore may have therapeutic potential for organ fibrosis.
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PMID:Decorin gene delivery inhibits cardiac fibrosis in spontaneously hypertensive rats by modulation of transforming growth factor-beta/Smad and p38 mitogen-activated protein kinase signaling pathways. 1969 98

Epithelial-mesenchymal transition (EMT) has emerged as a critical event in the pathogenesis of organ fibrosis and cancer and is typically induced by the multifunctional cytokine transforming growth factor (TGF)-beta1. The present study was undertaken to evaluate the potential role of phosphodiesterases (PDEs) in TGF-beta1-induced EMT in the human alveolar epithelial type II cell line A549. Stimulation of A549 with TGF-beta1 induced EMT by morphological alterations and by expression changes of the epithelial phenotype markers E-cadherin, cytokeratin-18, zona occludens-1, and the mesenchymal phenotype markers, collagen I, fibronectin, and alpha-smooth muscle actin. Interestingly, TGF-beta1 stimulation caused twofold increase in total cAMP-PDE activity, contributed mostly by PDE4. Furthermore, mRNA and protein expression demonstrated up-regulation of PDE4A and PDE4D isoforms in TGF-beta1-stimulated cells. Most importantly, treatment of TGF-beta1 stimulated epithelial cells with the PDE4-selective inhibitor rolipram or PDE4 small interfering RNA potently inhibited EMT changes in a Smad-independent manner by decreasing reactive oxygen species, p38, and extracellular signal-regulated kinase phosphorylation. In contrast, the ectopic overexpression of PDE4A and/or PDE4D resulted in a significant loss of epithelial marker E-cadherin but did not result in changes of mesenchymal markers. In addition, Rho kinase signaling activated by TGF-beta1 during EMT demonstrated to be a positive regulator of PDE4. Collectively, the findings presented herein suggest that TGF-beta1 mediated up-regulation of PDE4 promotes EMT in alveolar epithelial cells. Thus, targeting PDE4 isoforms may be a novel approach to attenuate EMT-associated lung diseases such as pulmonary fibrosis and lung cancer.
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PMID:Expression and activity of phosphodiesterase isoforms during epithelial mesenchymal transition: the role of phosphodiesterase 4. 1975 79

TGF-beta1 expression closely associates with activation and conversion of fibroblasts to a myofibroblast phenotype and synthesis of an alternatively spliced cellular fibronectin variant, Fn-ED-A. Reactive oxygen species (ROS), such as superoxide, which is a product of NAD(P)H oxidase, also promote the transition of fibroblasts to myofibroblasts, but whether these two pathways are interrelated is unknown. Here, we examined a role for NAD(P)H oxidase-derived ROS in TGF-beta1-induced activation of rat kidney fibroblasts and expression of alpha-smooth muscle actin (alpha-SMA) and Fn-ED-A. In vitro, TGF-beta1 stimulated formation of abundant stress fibers and increased expression of both alpha-SMA and Fn-ED-A. In addition, TGF-beta1 increased both the activity of NADPH oxidase and expression of Nox2 and Nox4, homologs of the NAD(P)H oxidase family, indicating that this growth factor induces production of ROS. Small interfering RNA targeted against Nox4 markedly inhibited TGF-beta1-induced stimulation of NADPH oxidase activity and reduced alpha-SMA and Fn-ED-A expression. Inhibition of TGF-beta1 receptor 1 blocked Smad3 phosphorylation; reduced TGF-beta1-enhanced NADPH oxidase activity; and decreased expression of Nox4, alpha-SMA, and Fn-ED-A. Diphenyleneiodonium, an inhibitor of flavin-containing enzymes such as the Nox oxidases, had no effect on TGF-beta1-induced Smad3 but reduced both alpha-SMA and Fn-ED-A protein expression. The Smad3 inhibitor SIS3 reduced NADPH oxidase activity, Nox4 expression, and blocked alpha-SMA and Fn-ED-A, indicating that stimulation of myofibroblast activation by ROS is downstream of Smad3. In addition, TGF-beta1 stimulated phosphorylation of extracellular signal-regulated kinase (ERK1/2), and this was inhibited by blocking TGF-beta1 receptor 1, Smad3, or the Nox oxidases; ERK1/2 activation increased alpha-SMA and Fn-ED-A. Taken together, these results suggest that TGF-beta1-induced conversion of fibroblasts to a myofibroblast phenotype involves a signaling cascade through Smad3, NAD(P)H oxidase, and ERK1/2.
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PMID:NAD(P)H oxidase mediates TGF-beta1-induced activation of kidney myofibroblasts. 1992 89

Epithelial-mesenchymal transition (EMT) is an important process that contributes to renal fibrogenesis. TGF-beta1 and EGF stimulate EMT. Recent studies suggested that parathyroid hormone-related protein (PTHrP) promotes fibrogenesis in the damaged kidney, apparently dependent on its interaction with vascular endothelial growth factor (VEGF), but whether it also interacts with TGF-beta and EGF to modulate EMT is unknown. Here, PTHrP(1-36) increased TGF-beta1 in cultured tubuloepithelial cells and TGF-beta blockade inhibited PTHrP-induced EMT-related changes, including upregulation of alpha-smooth muscle actin and integrin-linked kinase, nuclear translocation of Snail, and downregulation of E-cadherin and zonula occludens-1. PTHrP(1-36) also induced EGF receptor (EGFR) activation; inhibition of protein kinase C and metalloproteases abrogated this activation. Inhibition of EGFR activation abolished these EMT-related changes, the activation of ERK1/2, and upregulation of TGF-beta1 and VEGF by PTHrP(1-36). Moreover, inhibition of ERK1/2 blocked EMT induced by either PTHrP(1-36), TGF-beta1, EGF, or VEGF. In vivo, obstruction of mouse kidneys led to changes consistent with EMT and upregulation of TGF-beta1 mRNA, p-EGFR protein, and PTHrP. Taken together, these data suggest that PTHrP, TGF-beta, EGF, and VEGF might cooperate through activation of ERK1/2 to induce EMT in renal tubuloepithelial cells.
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PMID:Parathyroid hormone-related protein promotes epithelial-mesenchymal transition. 1995 11

Cinnamaldehyde is a major and a bioactive compound isolated from the leaves of Cinnamomum osmophloeum kaneh. To explore whether cinnamaldehyde was linked to altered high glucose (HG)-mediated renal tubulointerstitial fibrosis in diabetic nephropathy (DN), the molecular mechanisms of cinnamaldehyde responsible for inhibition of HG-induced hypertrophy in renal interstitial fibroblasts were examined. We found that cinnamaldehyde caused inhibition of HG-induced cellular mitogenesis rather than cell death by either necrosis or apoptosis. There were no changes in caspase 3 activity, cleaved poly(ADP-ribose) polymerase (PARP) protein expression, and mitochondrial cytochrome c release in HG or cinnamaldehyde treatments in these cells. HG-induced extracellular signal-regulated kinase (ERK)/c-Jun N-terminal kinase (JNK)/p38 mitogen-activated protein kinase (MAPK) (but not the Janus kinase 2/signal transducers and activators of transcription) activation was markedly blocked by cinnamaldehyde. The ability of cinnamaldehyde to inhibit HG-induced hypertrophy was verified by the observation that it significantly decreased cell size, cellular hypertrophy index, and protein levels of collagen IV, fibronectin, and alpha-smooth muscle actin (alpha-SMA). The results obtained in this study suggest that cinnamaldehyde treatment of renal interstitial fibroblasts that have been stimulated by HG reduces their ability to proliferate and hypertrophy through mechanisms that may be dependent on inactivation of the ERK/JNK/p38 MAPK pathway.
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PMID:Cinnamaldehyde impairs high glucose-induced hypertrophy in renal interstitial fibroblasts. 2006 12

Fibroblast differentiation into myofibroblasts is a key event during normal wound repair. We have previously demonstrated an age-related defect in this process associated with impaired synthesis of hyaluronan (HA) synthase (HAS) 2 but failed to prescribe its role in a mechanistic sense. Here we demonstrate that in addition to HAS2, there is loss of EGF receptor (EGF-R) in aged cells, and both are required for normal fibroblast functionality. Analysis of molecular events revealed that in young cells, transforming growth factor (TGF)-beta1-dependent phenotypic activation uses two distinct but cooperating pathways that involve TGF-beta receptor/Smad2 activation and EGF-mediated EGF-R/extracellular signal-regulated kinase (ERK) 1/2 signaling, and the latter is compromised with in vitro aging. Pharmacological inhibition of any of the five intermediates (TGF-beta receptor, Smad2, EGF, EGF-R, and ERK1/2) attenuated TGF-beta1 induction of alpha-smooth muscle actin. We present evidence that the HA receptor CD44 co-immunoprecipitates with EGF-R after activation by TGF-beta1. This interaction is HA-dependent because disruption of HA synthesis abrogates this association and inhibits subsequent ERK1/2 signaling. In aged fibroblasts, this association is lost with resultant suppression of ERK1/2 activation. Forced overexpression of EGF-R and HAS2 in aged cells restored TGF-beta1-mediated HA-CD44/EGF-R association and alpha-smooth muscle actin induction. Taken together, these results demonstrate that HA can serve as a signal integrator by facilitating TGF-beta1-mediated CD44-EGF-R-ERK interactions and ultimately fibroblast phenotype. We propose a model to explain this novel mechanism and the functional consequence of age-dependent dysregulation.
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PMID:Aging fibroblasts resist phenotypic maturation because of impaired hyaluronan-dependent CD44/epidermal growth factor receptor signaling. 2009 89

N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) inhibits collagen production and cell proliferation in cultured rat cardiac fibroblasts, but its effect on differentiation of fibroblasts into myofibroblasts is not known. High amounts of transforming growth factor-beta1 (TGF-beta1) have been found in fibrotic cardiac tissue. TGF-beta1 converts fibroblasts into myofibroblasts, which produce more extracellular matrix proteins than fibroblasts. We hypothesized that 1) Ac-SDKP inhibits TGF-beta1-induced differentiation of fibroblasts into myofibroblasts; and 2) this effect is mediated in part by blocking phosphorylation of small-mothers-against-decapentaplegic (Smad) 2 and extracellular signal-regulated kinase (ERK) 1/2. For this study, we used human fetal cardiac fibroblasts (HCFs), which do not spontaneously become myofibroblasts when cultured at low passages. We investigated the effect of Ac-SDKP on TGF-beta1-induced HCF transformation into myofibroblasts, Smad2 and ERK1/2 phosphorylation, Smad7 expression, cell proliferation, and collagen production. We also investigated TGF-beta1 production by HCFs stimulated with endothelin-1 (ET-1). As expected, HCFs treated with TGF-beta1 transformed into myofibroblasts as indicated by increased expression of alpha-smooth muscle actin and a higher proportion of the embryonic isoform of smooth muscle myosin compared with untreated cells. TGF-beta1 also increased Smad2 and ERK1/2 phosphorylation but did not affect Smad7 expression. In addition, TGF-beta1 stimulated HCF proliferation as indicated by an increase in mitochondrial dehydrogenase activity and collagen production (hydroxyproline assay). Ac-SDKP significantly inhibited all of the effects of TGF-beta1. It also inhibited ET-1-stimulated TGF-beta1 production. We concluded that Ac-SDKP markedly suppresses differentiation of human cardiac fibroblasts into myofibroblasts, probably by inhibiting the TGF-beta/Smad/ERK1/2 signaling pathway, and thus mediating its anti-fibrotic effects.
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PMID:Ac-SDKP inhibits transforming growth factor-beta1-induced differentiation of human cardiac fibroblasts into myofibroblasts. 2015 64


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