Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:2.7.11.24 (mitogen-activated protein kinase)
95,810 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Among the multiple cardiac manifestations occurring in HIV-infected patients, cardiomyopathy is one of the most challenging. Its incidence has only slightly decreased since the introduction of highly active antiretroviral therapy (HAART). Also, its pathogenesis remains relatively unclear. Although several studies demonstrated the presence of HIV genome in the heart of patients, more recent developments found that viral infection plays an indirect role only, as well as they recognized the contribution of proinflammatory cytokines in the progression of the disease. Experimental studies on animals and cultured myocytes have established the signalling pathway triggered by proinflammatory cytokines in heart failure and cardiomyopathy. Tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1) and IL-6 promote expression of inducible nitric oxide synthase (iNOS) in cardiomyocytes through activation of p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor kappaB (NFkappaB). TNF-alpha and high concentrations of NO also induce cardiomyocyte apoptosis by TNF type 1 receptor activation. This biological framework, which is also involved in progression of cardiomyopathy in humans, is more pronounced in HIV-infected patients, in whom proinflammatory cytokines TNF-alpha, IL-1 and IL-6 are increased, resulting in an enhanced expression of cardiac iNOS, especially in patients with a low CD4 T cell count. This may account for the worse outcome of heart failure in HIV-infected patients. However, there are only few data today to support future therapeutic implications of cytokines antagonism in treatment of HIV-infected patients with cardiomyopathy. Whether modulation of TNF production or selective inhibition of p38 MAPK pathway could be useful approaches remains uncertain.
...
PMID:Cytokines in HIV-associated cardiomyopathy. 1733 7

We examined the role of p38alpha MAPK in mediating cardiomyopathy in mice overexpressing beta(1)-adrenergic receptor (beta(1)-AR) or beta(2)-AR by mating them with dominant-negative p38alpha (DNp38alpha) MAPK mice. Both beta(1)-AR and beta(2)-AR Tg mice had enhanced LV ejection fraction (LVEF) as young adults and developed similar cardiomyopathy at 11-15 months, characterized by reduced LVEF, myocyte hypertrophy, fibrosis, and apoptosis. We inhibited p38alpha MAPK by mating beta(1)-AR Tg and beta(2)-AR Tg mice with DNp38alpha MAPK mice, which rescued the depressed LVEF and reduced apoptosis and fibrosis in bigenic beta(2)-AR x DNp38alpha MAPK mice, but not bigenic beta(1)-AR x DNp38alpha MAPK mice, and failed to reduce myocyte hypertrophy in either group. G(salpha) was increased in both beta(1)-AR Tg and beta(2)-AR Tg mice and was still present in bigenic beta(1)-AR x DNp38alpha MAPK mice, but not bigenic beta(2)-AR x DNp38alpha MAPK mice. This suggests that p38alpha MAPK is one critical downstream signal for the development of cardiomyopathy following chronic beta(2)-AR stimulation, but other kinases may be more important in ameliorating the adverse effects of chronic beta(1)-AR stimulation.
...
PMID:Inhibition of p38 alpha MAPK rescues cardiomyopathy induced by overexpressed beta 2-adrenergic receptor, but not beta 1-adrenergic receptor. 1744 30

Mutations in LMNA, which encodes nuclear Lamins A and C cause diseases affecting various organs, including the heart. We have determined the effects of an Lmna H222P mutation on signaling pathways involved in the development of cardiomyopathy in a knockin mouse model of autosomal dominant Emery-Dreifuss muscular dystrophy. Analysis of genome-wide expression profiles in hearts using Affymetrix GeneChips showed statistically significant differences in expression of genes in the MAPK pathways at the incipience of the development of clinical disease. Using real-time PCR, we showed that activation of MAPK pathways preceded clinical signs or detectable molecular markers of cardiomyopathy. In heart tissue and isolated cardiomyocytes, there was activation of MAPK cascades and downstream targets, implicated previously in the pathogenesis of cardiomyopathy. Expression of H222P Lamin A in cultured cells activated MAPKs and downstream target genes. Activation of MAPK signaling by mutant A-type lamins could be a cornerstone in the development of heart disease in autosomal dominant Emery-Dreifuss muscular dystrophy.
...
PMID:Activation of MAPK pathways links LMNA mutations to cardiomyopathy in Emery-Dreifuss muscular dystrophy. 1744 32

Mitofusin-2 (Mfn2) suppresses smooth muscle cell proliferation through inhibition of the Ras-extracellular signal-regulated kinases (ERK1/2) pathway. Since the ERK1/2 pathway is implicated in mediating hypertrophic signaling, we studied the changes in Mfn2 in cardiac hypertrophy using in vitro and in vivo models. Phenylephrine was used to induce hypertrophy in neonatal rat ventricular myocytes (NRVMs). In vivo hypertrophy models included spontaneously hypertensive rats (SHR), pressure-overload hypertrophy by transverse aortic constriction (TAC), hypertrophy of non-infarcted myocardium following myocardial infarction (MI), and cardiomyopathy due to cardiac-restricted overexpression of beta(2)-adrenergic receptors (beta(2)-TG). We determined hypertrophic parameters and analysed expression of atrial natriuretic peptide (ANP) and Mfn2 by real-time PCR. Phosphorylated-ERK1/2 (phospho-ERK) was measured by Western blot. Mfn2 was downregulated in phenylephrine treated NRCMs (by approximately 40%), hypertrophied hearts from SHR (by approximately 80%), mice with TAC (at 1 and 3 weeks, by approximately 50%), and beta(2)-TG mice (by approximately 20%). However, Mfn2 was not downregulated in hypertrophied hearts with 15 weeks of TAC, nor in hypertrophied non-infarcted myocardium following MI. phospho-ERK1/2 was increased in hypertrophied myocardium at 1 week post-TAC, but not in non-infarcted myocardium after MI, indicating that downregulated Mfn2 may be accompanied by an increase of phospho-ERK1/2. This study shows, for the first time, downregulated Mfn2 expression in hypertrophied hearts, which depends on the etiology and time course of hypertrophy. Further study is required to examine the causal relationship between Mfn2 and cardiac hypertrophy.
...
PMID:Down-regulation of mitofusin-2 expression in cardiac hypertrophy in vitro and in vivo. 1749 11

Evidence suggests that the autoimmune cardiomyopathy produced by a peptide corresponding to the sequence of the second extracellular loop of the beta(1)-adrenergic receptor (beta(1)-EC(II)) is mediated via a biologically active anti-beta(1)-EC(II) antibody, but the mechanism linking the antibody to myocyte apoptosis and cardiac dysfunction has not been well elucidated. Since the beta(1)-EC(II) autoantibody is a partial beta(1)-agonist, we speculate that the cardiomyopathy is produced by the beta(1)-receptor-mediated stimulation of the CaMKII-p38 MAPK-ATF6 signaling pathway and endoplasmic reticulum (ER) stress, and that excess norepinephrine (NE) exaggerates the cardiomyopathy. Rabbits were randomized to receive beta(1)-EC(II) immunization, sham immunization, NE pellet, or beta(1)-EC(II) immunization plus NE pellet for 6 mo. Heart function was measured by echocardiography and catheterization. Myocyte apoptosis was determined by terminal deoxytransferase-mediated dUTP nick-end labeling and caspase-3 activity, whereas CaMKII, MAPK family (JNK, p38, ERK), and ER stress signals (ATF6, GRP78, CHOP, caspase-12) were measured by Western blot, immunohistochemistry, and kinase activity assay. beta(1)-EC(II) immunization produced progressive LV dilation, systolic dysfunction, and myocyte apoptosis. These changes were associated with activation of GRP78 and CHOP and increased cleavage of caspase-12, as well as increased CaMKII activity, increased phosphorylation of p38 MAPK, and nucleus translocation of cleaved ATF6. NE pellet produced additive effects. In addition, KN-93 and SB 203580 abolished the induction of ER stress and cell apoptosis produced by the beta(1)-EC(II) antibody in cultured neonatal cardiomyocytes. Thus ER stress occurs in autoimmune cardiomyopathy induced by beta(1)-EC(II) peptide, and this is enhanced by increased NE and caused by activation of the beta(1)-adrenergic receptor-coupled CaMKII, p38 MAPK, and ATF6 pathway.
...
PMID:Cardiomyocyte apoptosis in autoimmune cardiomyopathy: mediated via endoplasmic reticulum stress and exaggerated by norepinephrine. 1754 81

Emery-Dreifuss muscular dystrophy (EDMD) is an inherited disorder characterized by slowly progressive skeletal muscle weakness in a humero-peroneal distribution, early contractures and prominent cardiomyopathy with conduction block. Mutations in EMD, encoding emerin, and LMNA, encoding A-type lamins, respectively, cause X-linked and autosomal dominant EDMD. Emerin and A-type lamins are proteins of the inner membrane of the nuclear envelope. Whereas the genetic cause of EDMD has been described and the proteins well characterized, little is known on how abnormalities in nuclear envelope proteins cause striated muscle disease. In this study, we analyzed genome-wide expression profiles in hearts from Emd knockout mice, a model of X-linked EDMD, using Affymetrix GeneChips. This analysis showed a molecular signature similar to that we previously described in hearts from Lmna H222P knock-in mice, a model of autosomal dominant EDMD. There was a common activation of the ERK1/2 branch of the mitogen-activated protein kinase (MAPK) pathway in both murine models, as well as activation of downstream targets implicated in the pathogenesis of cardiomyopathy. Activation of MAPK signaling appears to be a cornerstone in the development of heart disease in both X-linked and autosomal dominant EDMD.
...
PMID:Activation of MAPK in hearts of EMD null mice: similarities between mouse models of X-linked and autosomal dominant Emery Dreifuss muscular dystrophy. 1756 79

The cardiofaciocutaneous (CFC) syndrome is characterized by congenital heart defect, developmental delay, peculiar facial appearance with bitemporal constriction, prominent forehead, downslanting palpebral fissures, curly sparse hair and abnormalities of the skin. CFC syndrome phenotypically overlaps with Noonan and Costello syndromes. Mutations of several genes (PTPN11, HRAS, KRAS, BRAF, MEK1 and MEK2), involved in the mitogen-activated protein kinase (MAPK) pathway, have been identified in CFC-Costello-Noonan patients. Coenzyme Q10 (CoQ10), a lipophilic molecule present in all cell membranes, functions as an electron carrier in the mitochondrial respiratory chain, where it transports electrons from complexes I and II to complex III. CoQ10 deficiency is a rare treatable mitochondrial disorder with various neurological (cerebellar ataxia, myopathy, epilepsy, mental retardation) and extraneurological (cardiomyopathy, nephropathy) signs that are responsive to CoQ10 supplementation. We report the case of a 4-year-old girl who presented a CFC syndrome, confirmed by the presence of a pathogenic R257Q BRAF gene mutation, together with a muscular CoQ10 deficiency. Her psychomotor development was severely impaired, hindered by muscular hypotonia and ataxia, both improving remarkably after CoQ10 treatment. This case suggests that there is a functional connection between the MAPK pathway and the mitochondria. This could be through the phosphorylation of a nuclear receptor essential for CoQ10 biosynthesis. Another hypothesis is that K-Ras, one of the proteins composing the MAPK pathway, might be recruited into the mitochondria to promote apoptosis. This case highlights that CoQ10 might contribute to the pathogenesis of CFC syndrome.
...
PMID:Cardiofaciocutaneous (CFC) syndrome associated with muscular coenzyme Q10 deficiency. 1770 71

Caveolin-1 (Cav-1) is the principal structural component of caveolae organelles in smooth muscle cells, adipocytes, fibroblasts, epithelial cells, and endothelial cells (ECs). Cav-1-deficient (Cav-1 knockout [KO]) mice are viable and show increases of nitric oxide (NO) production in vasculature, cardiomyopathy, and pulmonary dysfunction. In this study, we generated EC-specific Cav-1-reconstituted (Cav-1 RC) mice and reexamined vascular, cardiac, and pulmonary phenotypes. Cav-1 KO pulmonary arteries had decreased smooth muscle contractility and increased endothelial NO synthase activation and hypotension; the latter two effects were rescued completely in Cav-1 RC mice. Cav-1 KO mice exhibited myocardial hypertrophy, pulmonary hypertension, and alveolar cell hyperproliferation caused by constitutive activation of p42/44 mitogen-activated protein kinase and Akt. Interestingly, in Cav-1 RC mice, cardiac hypertrophy and pulmonary hypertension were completely rescued, whereas alveolar hyperplasia was partially recovered because of the lack of rescue of Cav-1 in bronchiolar epithelial cells. These results provide clear physiological evidence supporting the important role of cell type-specific Cav-1 expression governing multiple phenotypes in the vasculature, heart, and lung.
...
PMID:Reexpression of caveolin-1 in endothelium rescues the vascular, cardiac, and pulmonary defects in global caveolin-1 knockout mice. 1789 96

Doxorubicin is a frequently used anticancer drug, but its therapeutic benefit is limited by acute and chronic cardiotoxicity, often leading to heart failure. The mechanisms underlying doxorubicin-induced cardiotoxicity remain unclear. It was previously shown in men that doxorubicin leads to increased endothelin-1 plasma levels. In addition, cardiac-specific overexpression of endothelin-1 in mice resulted in a cardiomyopathy resembling the phenotype following doxorubicin administration. We therefore hypothesized that endothelin-1 is involved in the pathogenesis of doxorubicin cardiotoxicity. In mice (C57Bl/10), we found that doxorubicin (20 mg/kg body weight, i.p.) impaired cardiac function with decreased ejection fraction, diminished cardiac output, and decreased end-systolic pressure points recorded by a microconductance catheter. This impaired function was accompanied by the up-regulation of endothelin-1 expression on mRNA and protein level. In vitro investigations confirmed the regulation of endothelin-1 by doxorubicin and indicated that the doxorubicin-mediated increase of endothelin-1 expression involves epidermal growth factor receptor signaling via the MEK1/2-ERK1/2 cascade, which was further confirmed by immunoblotting studies in the left ventricle of treated animals. Pretreatment of mice with the endothelin receptor antagonist bosentan (100 mg/kg body weight, p.o.) strikingly inhibited doxorubicin-induced cardiotoxicity with preserved indices of contractility. Moreover, bosentan pretreatment resulted in reduced tumor necrosis factor-alpha content, lipid peroxidation, and Bax expression, as well as increased GATA-4 expression. Thus, endothelin-1 plays a key role in mediating the cardiotoxic effects of doxorubicin and its inhibition may be of therapeutic benefit for patients receiving doxorubicin.
...
PMID:The endothelin receptor blocker bosentan inhibits doxorubicin-induced cardiomyopathy. 1797 86

Hepatocyte growth factor (HGF) reportedly exerts beneficial effects on the heart following myocardial infarction and during nonischemic cardiomyopathy, but the precise mechanisms underlying the latter have not been well elucidated. We generated nonischemic cardiomyopathy in mice by injecting them with doxorubicin (15 mg/kg ip). Two weeks later, when cardiac dysfunction was apparent, an adenoviral vector encoding human HGF gene (Ad.CAG-HGF, 1x10(11) particles/mouse) was injected into the hindlimb muscles; LacZ gene served as the control. Left ventricular dilatation and dysfunction normally seen 4 wk after doxorubicin administration were significantly mitigated in HGF-treated mice, as were the associated cardiomyocyte atrophy/degeneration and myocardial fibrosis. Myocardial expression of GATA-4 and a sarcomeric protein, myosin heavy chain, was downregulated by doxorubicin, but the expression of both was restored by HGF treatment. The protective effect of HGF against doxorubicin-induced cardiomyocyte atrophy was confirmed in an in vitro experiment, which also showed that neither cardiomyocyte apoptosis nor proliferation plays significant roles in the present model. Upregulation of c-Met/HGF receptor was noted in HGF-treated hearts. Among the mediators downstream of c-Met, the activation of extracellular signal-regulated kinase (ERK) was reduced by doxorubicin, but the activity was restored by HGF. Levels of transforming growth factor-beta1 and cyclooxygenase-2 did not differ between the groups. Our findings suggest the HGF gene delivery exerts therapeutic antiatrophic/degenerative and antifibrotic effects on myocardium in cases of established cardiac dysfunction caused by doxorubicin. These beneficial effects appear to be related to HGF-induced ERK activation and upregulation of c-Met, GATA-4, and sarcomeric proteins.
...
PMID:Treatment with an adenoviral vector encoding hepatocyte growth factor mitigates established cardiac dysfunction in doxorubicin-induced cardiomyopathy. 1808 97


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

---