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Query: EC:2.7.10.2 (
focal adhesion kinase
)
44,029
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
This minireview is an update of a 1997 review on erythropoietin (EPO) in this journal. EPO is a 30,400-dalton glycoprotein that regulates red cell production. In the human, EPO is produced by peritubular cells in the kidneys of the adult and in hepatocytes in the fetus. Small amounts of extra-renal EPO are produced by the liver in adult human subjects. EPO binds to an erythroid progenitor cell surface receptor that includes a p66 chain, and, when activated, the p66 protein becomes dimerized. EPO receptor activation induces a
JAK2
tyrosine kinase, which leads to tyrosine phosphorylation of the EPO receptor and several proteins. EPO receptor binding leads to intracellular activation of the Ras/mitogen-activated kinase pathway, which is involved with cell proliferation, phosphatidylinositol 3-kinase, and STATS 1, 3, 5A, and 5B transcriptional factors. EPO acts primarily to rescue erythroid cells from apoptosis (programmed cell death) to increase their survival. EPO acts synergistically with several growth factors (SCF, GM-CSF, 1L-3, and IGF-1) to cause maturation and proliferation of erythroid progenitor cells (primarily colony-forming unit-E). Oxygen-dependent regulation of EPO gene expression is postulated to be controlled by a hypoxia-inducible transcription factor (HIF-1alpha). Hypoxia-inducible EPO production is controlled by a 50-bp hypoxia-inducible enhancer that is approximately 120 bp 3' to the polyadenylation site. Hypoxia signal transduction pathways involve kinases A and C, phospholipase A(2), and transcription factors ATF-1 and CREB-1. A model has been proposed for adenosine activation of EPO production that involves protein kinases A and C and the phospholipase A(2) pathway. Other effects of EPO include a hematocrit-independent, vasoconstriction-dependent hypertension, increased endothelin production, upregulation of tissue
renin
, change in vascular tissue prostaglandins production, stimulation of angiogenesis, and stimulation of endothelial and vascular smooth muscle cell proliferation. Recombinant human EPO (rHuEPO) is currently being used to treat patients with anemias associated with chronic renal failure, AIDS patients with anemia due to treatment with zidovudine, nonmyeloid malignancies in patients treated with chemotherapeutic agents, perioperative surgical patients, and autologous blood donation. A novel erythropoiesis-stimulating factor (NESP, darbepoetin) has been synthesized and when compared with rHuEPO, NESP has a higher carbohydrate content (52% vs 40%), a longer plasma half-life, the amino acid sequence differs from that of native human EPO at five positions, and has been reported to maintain hemoglobin levels just as effectively in patients with chronic renal failure as rHuEPO at less frequent dosing. The use of rHuEPO and darbepoetin to enhance athletic performance is officially banned by most sports-governing bodies because the excessive erythrocytosis can lead to increased thrombogenicity and can cause deep vein, coronary, and cerebral thromboses.
...
PMID:Erythropoietin: physiology and pharmacology update. 1252 67
Although both the
renin
angiotensin system (RAS) and the paired homeobox 2 gene (Pax-2) seem critically important in renal organogenesis, whether and how they might interact has not been addressed. The present study asked whether a link between the RAS and Pax-2 exists in fetal renal cells, speculating that such an interaction, if present, might influence renal development. Embryonic kidney explants and embryonic renal cells (mouse late embryonic mesenchymal epithelial cells [MK4] and mouse early embryonic mesenchymal fibroblasts [MK3]) were used. Pax-2 protein and Pax-2 mRNA were detected by immunofluorescence, Western blot, reverse transcription-PCR, and real-time PCR. Angiotensin II (AngII) upregulated Pax-2 protein and Pax-2 mRNA expression via the AngII type 2 (AT(2)) receptor in MK4 but not in MK3 cells. The stimulatory effect of AngII on Pax-2 gene expression could be blocked by PD123319 (AT(2) inhibitor), AG 490 (a specific
Janus kinase 2
inhibitor), and genistein (a tyrosine kinase inhibitor) but not by losartan (AT(1) inhibitor), SB203580 (specific p38 mitogen-activated protein kinase inhibitor), PD98059 (specific MEK inhibitor), SP600125 (JNK inhibitor), and diphenyleneiodonium chloride (an NADPH oxidase inhibitor). Moreover, embryonic kidney explants in culture confirmed that AngII upregulates Pax-2 gene expression via the AT(2) receptor. These studies demonstrate that the stimulatory effect of AngII on Pax-2 gene expression is mediated, at least in part, via the
Janus kinase 2
/signal transducers and activators of transcription signaling transduction pathway, suggesting that RAS and Pax-2 interactions may be important in renal development.
...
PMID:Angiotensin II increases Pax-2 expression in fetal kidney cells via the AT2 receptor. 1515 56
Enhanced blood pressure variability contributes to left ventricular hypertrophy and end-organ damage, even in the absence of hypertension. We hypothesized that the greater number of high-blood pressure episodes associated with enhanced blood pressure variability causes cardiac hypertrophy and dysfunction by activation of mechanosensitive and autocrine pathways. Normotensive mice were subjected to sinoaortic baroreceptor denervation (SAD) or sham surgery. Twelve weeks later, blood pressure variability was doubled in SAD compared with sham-operated mice. Blood pressure did not differ. Cardiac hypertrophy was reflected in greater heart/body weight ratios, larger myocyte cross-sectional areas, and greater left ventricular collagen deposition. Furthermore, left ventricular atrial and brain natriuretic peptide mRNA expression was greater in SAD than in sham-operated mice. SAD had higher left ventricular end-diastolic pressures and lower myocardial contractility indexes, indicating cardiac dysfunction. Cardiac protein content of phosphorylated p125
focal adhesion kinase
(p125
FAK
) and phosphorylated p38 mitogen-activated protein kinase (p38 MAPK) was greater in SAD than in sham-operated mice, indicating activation of mechanosensitive pathways of cardiac hypertrophy. Furthermore, enhanced cardiac
renin
and transforming growth factor-beta1 (TGFbeta1) protein content indicates activation of autocrine pathways of cardiac hypertrophy. Adrenal tyrosine hydroxylase protein content and the number of
renin
-positive glomeruli were not different, suggesting that sympathetic activation and the systemic
renin
-angiotensin system did not contribute to cardiac hypertrophy. In conclusion, more frequent blood pressure rises in subjects with high blood pressure variability activate mechanosensitive and autocrine pathways leading to cardiac hypertrophy and dysfunction even in the absence of hypertension.
...
PMID:Mechanisms of blood pressure variability-induced cardiac hypertrophy and dysfunction in mice with impaired baroreflex. 1556 77
Aldosterone is currently recognized as a risk hormone for cardiovascular disease. However, the cellular mechanism by which aldosterone acts on vasculature has not been well understood. In the present study, we investigated whether aldosterone affects angiotensin-converting enzyme (ACE) gene expression in rat endothelial cells. Cultured rat aortic endothelial cells (RAECs) from Sprague-Dawley rats were used in the study. ACE mRNA levels and its enzyme activities in RAECs were examined by real-time RT-PCR and enzyme assay using hippuryl-His-Leu as substrates, respectively. Aldosterone significantly increased steady-state ACE mRNA levels and its enzymatic activities. This effect was dose dependent and time dependent and abolished by mineralocorticoid receptor antagonist spironolactone or transcription inhibitor actinomycin D. Dexamethasone also increased steady-state ACE mRNA levels, whose effect was completely blocked by glucocorticoid receptor antagonist RU486, but not by spironolactone. By contrast, the aldosterone-induced ACE mRNA expression was only partially blocked by RU486. The stimulatory effect of aldosterone on ACE mRNA expression was completely blocked by a protein tyrosine kinase inhibitor (genistein) and
JAK2
inhibitor (AG490), partially by Src kinase inhibitor (PP2) and epidermal growth factor receptor kinase inhibitor (AG1478), but not by platelet-derived growth factor receptor kinase inhibitor (AG1296). Transfection of dominant-negative
JAK2
construct, but not wild-type construct, significantly blocked the aldosterone-induced ACE mRNA up-regulation. Furthermore, aldosterone induced phosphorylation of
JAK2
, whose effect was blocked by spironolactone and actinomycin D. In conclusion, the present study demonstrates for the first time that aldosterone induces ACE gene expression and its enzyme activity mainly via a mineralocorticoid receptor-mediated and
JAK2
-dependent pathway in rat endothelial cells. This may constitute a positive feedback loop for a local
renin
-angiotensin system, possibly involved in the development of aldosterone-induced endothelial dysfunction and vascular injury.
...
PMID:Aldosterone induces angiotensin converting enzyme gene expression via a JAK2-dependent pathway in rat endothelial cells. 1593 31
While angiotensin II (Ang II) has been shown to inhibit migration of extravillous trophoblasts via plasminogen activator inhibitor-1 (PAI-1) activation, it has remained unclear whether it stimulates or inhibits malignant behavior of choriocarcinoma cells. Since we previously found an involvement of the
renin
-angiotensin system (RAS) in the proliferative potential in choriocarcinoma cells (BeWo), mediated via the Ang II type 1 receptor (AT1R), in the present study we investigated the effects of Ang II on choriocarcinoma cell migration/invasion in vitro using Transwell cell culture chambers. Ang II (10(-8)M) promoted migration and invasion by a choriocarcinoma cell line and augmented random cell mobility on checkerboard analysis. Immunoblotting showed Ang II to activate the phosphorylation of
FAK
and Akt in BeWo cells. Furthermore Ang II effects on cell migration were abolished by a selective AT1R antagonist and a phosphatidylinositol 3-kinase (PI3K) inhibitor. The present results suggest that Ang II-induced migration and invasion of choriocarcinoma cells probably involves PI3K following binding to the AT1R.
...
PMID:Angiotensin II augmented migration and invasion of choriocarcinoma cells involves PI3K activation through the AT1 receptor. 1612 87
Familial renal glucosuria (FRG) is an inherited renal tubular disorder characterized by persistent isolated glucosuria in the absence of hyperglycemia. Mutations in the sodium/glucose co-transporter SGLT2 coding gene, SLC5A2, were recently found to be responsible for the disorder. Here, we report the molecular and phenotype study of five unrelated FRG families. Five patients were identified and their family members screened for glucosuria. SLC5A2 coding region of index cases was polymerase chain reaction amplified and sequenced. Five different mutations are reported, including four novel alleles. The IVS12+1G>A and p.A102V alleles were identified in homozygosity in index patients of two unrelated families. A proband from another family was compound heterozygous for the p.R132H and p.A219T mutations, and the heterozygous p.Q167fsX186 frameshift allele was the only mutation detected in the affected individual from an additional pedigree. For the remaining family no mutations were detected. The patient homozygous for the p.A102V mutation had glucosuria of 65.6 g/1.73 m(2)/24 h, evidence of renal sodium wasting, mild volume depletion, and raised basal plasma
renin
and serum aldosterone levels. Our findings confirm previous observations that in FRG, transmitted as a codominant trait with incomplete penetrance, most mutations are private. In the only patient with massive glucosuria in our cohort there was evidence evocative of
renin
-angiotensin aldosterone system activation by extracellular volume depletion induced by natriuresis. Definite proof of
renin
-angiotensin aldosterone system activation in
FGR
should rely on evaluation of additional patients with massive glucosuria.
...
PMID:Familial renal glucosuria: SLC5A2 mutation analysis and evidence of salt-wasting. 1651 45
The
renin
-angiotensin system is a central component of the physiological and pathological responses of cardiovascular system. Its primary effector hormone, angiotensin II (ANG II), not only mediates immediate physiological effects of vasoconstriction and blood pressure regulation, but is also implicated in inflammation, endothelial dysfunction, atherosclerosis, hypertension, and congestive heart failure. The myriad effects of ANG II depend on time (acute vs. chronic) and on the cells/tissues upon which it acts. In addition to inducing G protein- and non-G protein-related signaling pathways, ANG II, via AT(1) receptors, carries out its functions via MAP kinases (ERK 1/2, JNK, p38MAPK), receptor tyrosine kinases [PDGF, EGFR, insulin receptor], and nonreceptor tyrosine kinases [Src, JAK/STAT,
focal adhesion kinase
(
FAK
)]. AT(1)R-mediated NAD(P)H oxidase activation leads to generation of reactive oxygen species, widely implicated in vascular inflammation and fibrosis. ANG II also promotes the association of scaffolding proteins, such as paxillin, talin, and p130Cas, leading to focal adhesion and extracellular matrix formation. These signaling cascades lead to contraction, smooth muscle cell growth, hypertrophy, and cell migration, events that contribute to normal vascular function, and to disease progression. This review focuses on the structure and function of AT(1) receptors and the major signaling mechanisms by which angiotensin influences cardiovascular physiology and pathology.
...
PMID:Angiotensin II cell signaling: physiological and pathological effects in the cardiovascular system. 1687 Aug 27
The precise mechanism by which cytokines such as IL-1beta negatively modulate expression of the
renin
gene remains incomplete. IL-1beta can repress
renin
transcription under both baseline and retinoic acid-stimulated conditions in As4.1 cells, a
renin
-expressing cell line derived from the kidney. This repression does not require a negative regulatory element present in the
renin
enhancer but is optimal in the presence of the entire
renin
enhancer. Three tandem copies of the retinoic acid response element is sufficient to attenuate the retinoic acid-response by IL-1beta. The decrease in retinoic acid-induced
renin
promoter activity in response to IL-1beta was blocked with the general tyrosine kinase inhibitor Genistein. IL-1beta caused an increase in the phosphorylation of ERK, but not p38MAPK or c-Jun N-terminal kinase. PD98059, an Erk kinase inhibitor, significantly decreased IL-1beta-mediated phosphorylation of ERK1/2, and attenuated the repression of baseline
renin
transcription in response to IL-1beta. PD98059 partially reversed the IL-1beta effect on retinoic acid-mediated transcription. To further investigate this mechanism, we searched the downstream effectors of ERK1/2 pathway. Although there was no effect of IL-1beta on the phosphorylation of ELK,
Janus kinase 2
, or signal transducers and activators of transcription (STAT) 1, IL-1beta significantly increased tyrosine-phosphorylation of STAT3, an effect attenuated by PD98059. STAT3 overexpression significantly repressed transcription of the
renin
gene, whereas small interfering RNA-mediated knockdown of STAT3 increased
renin
at baseline and attenuated the IL-1beta response. We conclude that in As4.1 cells, IL-1beta down-regulates
renin
gene expression via a mechanism involving the Erk-STAT3 pathway.
...
PMID:Interleukin-1beta attenuates renin gene expression via a mitogen-activated protein kinase kinase-extracellular signal-regulated kinase and signal transducer and activator of transcription 3-dependent mechanism in As4.1 cells. 1695 49
Recent observations raise possibility for constitutively active, mutated
JAK2
to modulate expression of RAS genes in CMPD. We analyzed the expression of AGT,
renin
, AT2R1 and ACE genes in normal and bone marrows of PV and ET patients with the respect to the presence of V617F
JAK2
mutation. PV and ET had different expression patterns of major RAS components compared to normal BM which was primarily associated with the JAK2V617F mutation and less with PV or ET disease phenotype. However, AT2R1 was exclusively markedly upregulated only in PV, while ET showed moderate expression irrespective of the
JAK2
mutational status.
...
PMID:Bone marrow renin-angiotensin system expression in polycythemia vera and essential thrombocythemia depends on JAK2 mutational status. 1787 18
Fibrosis is defined by the overgrowth, hardening, and/or scarring of various tissues and is attributed to excess deposition of extracellular matrix components including collagen. Fibrosis is the end result of chronic inflammatory reactions induced by a variety of stimuli including persistent infections, autoimmune reactions, allergic responses, chemical insults, radiation, and tissue injury. Although current treatments for fibrotic diseases such as idiopathic pulmonary fibrosis, liver cirrhosis, systemic sclerosis, progressive kidney disease, and cardiovascular fibrosis typically target the inflammatory response, there is accumulating evidence that the mechanisms driving fibrogenesis are distinct from those regulating inflammation. In fact, some studies have suggested that ongoing inflammation is needed to reverse established and progressive fibrosis. The key cellular mediator of fibrosis is the myofibroblast, which when activated serves as the primary collagen-producing cell. Myofibroblasts are generated from a variety of sources including resident mesenchymal cells, epithelial and endothelial cells in processes termed epithelial/endothelial-mesenchymal (
EMT
/EndMT) transition, as well as from circulating fibroblast-like cells called fibrocytes that are derived from bone-marrow stem cells. Myofibroblasts are activated by a variety of mechanisms, including paracrine signals derived from lymphocytes and macrophages, autocrine factors secreted by myofibroblasts, and pathogen-associated molecular patterns (PAMPS) produced by pathogenic organisms that interact with pattern recognition receptors (i.e. TLRs) on fibroblasts. Cytokines (IL-13, IL-21, TGF-beta1), chemokines (MCP-1, MIP-1beta), angiogenic factors (VEGF), growth factors (PDGF), peroxisome proliferator-activated receptors (PPARs), acute phase proteins (SAP), caspases, and components of the
renin
-angiotensin-aldosterone system (ANG II) have been identified as important regulators of fibrosis and are being investigated as potential targets of antifibrotic drugs. This review explores our current understanding of the cellular and molecular mechanisms of fibrogenesis.
...
PMID:Cellular and molecular mechanisms of fibrosis. 1816 45
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