scholarly journals Inhibition of immediate-early-gene induction in renal mesangial cells by depletion of intracellular polyamines

1994 ◽  
Vol 298 (3) ◽  
pp. 647-653 ◽  
Author(s):  
E Schulze-Lohoff ◽  
H Fees ◽  
S Zanner ◽  
K Brand ◽  
R B Sterzel
Keyword(s):  
Mrna Expression ◽  
Phospholipase C ◽  
Mesangial Cells ◽  
Inositol Phosphates ◽  
Calf Serum ◽  
Inhibitory Effect ◽  
Early Gene ◽  
Immediate Early ◽  
Dependent Manner ◽  
Inhibitor Of Protein Synthesis

Mitogens have been shown to stimulate the activity of the rate-limiting enzyme for polyamine synthesis, ornithine decarboxylase (ODC), and ODC mRNA expression in cultured rat mesangial cells (MCs). In addition, inhibition of ODC by alpha-difluoromethylornithine (DFMO) results in growth arrest of MCs. To elucidate the mechanisms involved in the inhibition of MC proliferation due to polyamine depletion, we studied the effects of DFMO on the activation of phospholipase C and induction of the immediate early genes (IEGs), c-fos, c-jun and Egr-1, which are thought to regulate cell growth. Mitogenic 10% fetal-calf serum (FCS) and 1 unit/ml thrombin activated phospholipase C in MCs within 30 s, as assessed by generation of [3H]inositol phosphates. This activation was not affected by DFMO. mRNAs of the IEGs c-fos, c-jun and Egr-1 were induced by FCS within 15 min. Expression of these genes reached a peak at 60 min and disappeared at 3 h. Treatment of MCs with a growth-suppressing dose of DFMO (5 mM) inhibited mRNAs of all three IEGs by 52-87% at 1 h. Total expression of Egr-1 over 20-120 min was diminished by 41%, and the time point of maximal expression was delayed by 40 min. This inhibitory effect was abolished in a time-dependent manner (1-3 days) by prior addition of 200 microM putrescine, the reaction product of ODC. Egr-1 mRNA expression was super-induced by the inhibitor of protein synthesis, cycloheximide. This effect was also blocked by DFMO. The results indicate that the DFMO-induced process of MC growth inhibition involves steps necessary for IEG activation. The signal-transduction step sensitive to polyamines occurs distal to the activation of phospholipase C. Since reconstitution of normal induction of IEGs requires 3 days, it seems likely that polyamine depletion affects the regulation of IEG expression in an indirect fashion. We conclude that activation of IEGs requires the presence of polyamines and plays a significant role in the induction of MC replication.

Cadmium and platinum suppression of erythropoietin production in cell culture: clinical implications

Blood ◽  
2000 ◽  
Vol 96 (12) ◽  
pp. 3743-3747 ◽  
Author(s):  
Hyogo Horiguchi ◽  
Fujio Kayama ◽  
Etsuko Oguma ◽  
William G. Willmore ◽  
Pavel Hradecky ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Cell Damage ◽  
Hepatoma Cell ◽  
Inhibitory Effect ◽  
Binding Activity ◽  
Hepatoma Cell Line ◽  
Dependent Manner ◽  
Toxic Exposure ◽  
Human Hepatoma Cell ◽  
Simultaneous Exposure

Abstract Both toxic exposure to cadmium and cancer therapy with cisplatin (CDDP) can induce anemia in patients owing to the insufficient production of erythropoietin (EPO). Therefore, the effects of cadmium chloride (Cd) and CDDP in the Hep3B human hepatoma cell line, which up-regulates EPO expression in response to hypoxia and cobalt (Co), were investigated. The induction of binding activity of the HIF-1 transcription factor and EPO mRNA expression and protein production were suppressed by Cd and CDDP in a dose-dependent manner with no apparent cell damage. Mercuric chloride also suppressed hypoxia- and Co-induced EPO production, mRNA expression, and HIF-1 binding in a manner similar to Cd and CDDP, whereas zinc chloride suppressed Co-induced EPO production, mRNA expression, and HIF-1 binding but did not affect hypoxia induction or that observed after simultaneous exposure to hypoxia and Co. In contrast, lead and tin salts had no effect on HIF-1 activation or EPO expression. These results indicate that Cd and CDDP have a strong and specific inhibitory effect on hypoxia- and Co-induced signaling and EPO induction in hepatic cells. It is likely that these agents cause anemia by directly impacting EPO production in the kidney.

Immune complex activation of rat glomerular mesangial cells: dependence on the Fc region of antibody

1989 ◽  
Vol 257 (3) ◽  
pp. F478-F485
Author(s):  
T. C. Knauss ◽  
P. Mene ◽  
S. A. Ricanati ◽  
M. Kester ◽  
G. R. Dubyak ◽  
...  
Keyword(s):  
Specific Antibody ◽  
Mesangial Cell ◽  
Mesangial Cells ◽  
Inositol Phosphates ◽  
Exchange Chromatography ◽  
Water Soluble ◽  
Free Calcium ◽  
Dependent Manner ◽  
Glomerular Mesangial Cells ◽  
Cross Sectional

Glomerulonephritis is frequently associated with immunoglobulin deposition in the mesangium. We had previously shown that contractile, rat mesangial cells in culture synthesize superoxide anion after binding immune complexes (IC) in a manner dependent on the Fc region of immunoglobulin G (IgG). We now studied the effects of soluble IC on mesangial cell cytosolic free calcium ([Ca2+]i) and phosphatidylinositol turnover as putative mechanisms of transmembrane signaling as well as prostaglandin biosynthesis and contraction. IC (500 micrograms specific antibody) raised [Ca2+]i in mesangial cells loaded with fura-2 from resting levels of 100.4 +/- 8.0 to a peak of 282.3 +/- 31.5 nM in a dose-dependent manner. Removal of extracellular Ca2+ by ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid only slightly reduced peak, IC-stimulated [Ca2+]i to 236 +/- 18 nM but prevented the sustained phase of the response, indicating that IC both mobilized Ca2+ from intracellular stores and increased the influx of Ca2+ across the plasma membrane. IC did not increase water-soluble inositol phosphates, measured by anion-exchange chromatography of trichloroacetic acid-extracted cells but markedly stimulated PGE2 and thromboxane B2 synthesis in a dose- and time-dependent manner. Finally, IC (250 micrograms specific antibody) induced 45.8 +/- 10.1% of the cells to contract with an average decrease in cross-sectional surface area of 20.0 +/- 1.8% of basal as assessed by image-analysis microscopy. IC formed with F(ab')2 fragments of antibody and antigen or mixtures of antigen and nonimmune whole molecule antibody did not alter [Ca2+]i, induce prostaglandin synthesis, or stimulate mesangial cell contraction.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals BMP-4 inhibits follicle-stimulating hormone secretion in ewe pituitary

2005 ◽  
Vol 186 (1) ◽  
pp. 109-121 ◽  
Author(s):  
M-O Faure ◽  
L Nicol ◽  
S Fabre ◽  
J Fontaine ◽  
N Mohoric ◽  
...  
Keyword(s):  
Growth Factor ◽  
Mrna Expression ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Hormone Secretion ◽  
Inhibitory Effect ◽  
Type I ◽  
Mrna Levels ◽  
Dependent Manner

Activins and inhibins, members of the transforming growth factor-beta family are able to stimulate and inhibit, respectively, FSH synthesis and release. Other members of this superfamily, the bone morphogenetic proteins (BMPs), may also affect FSH synthesis in the mouse. The aim of this work was to determine whether BMPs are expressed in the ovine pituitary and whether they play a role in the regulation of FSH release. The mRNAs encoding BMP-2, BMP-4, BMP-7 and the oocyte-derived growth factor, growth differentiation factor (GDF)-9 were detected in the pituitaries of cyclic ewes by reverse-transcriptase PCR, as well as the mRNAs encoding the BMP type I receptors, BMPR-IA (activin-receptor-like kinase (ALK)-3) and BMPR-IB (ALK-6), and type II receptors (BMPR-II). Immunolabeling of pituitary sections revealed the presence of BMPR-IA (ALK-3) and BMPR-II in gonadotrope cells. To investigate the potential effects of BMPs on FSH secretion, ewe pituitary cell cultures were treated with BMP-4 (10−11 M to 10−9 M) for 48 h. Interestingly, FSH release was decreased in a dose-dependent manner. At 10−9 M BMP-4 both FSH concentration and FSHβ mRNA expression were reduced by 40% of control values. In contrast, there was no inhibitory effect on either LH or LHβ mRNA expression. A similar result was found with BMP-6. BMP-4 triggered the phosphorylation of Smad1, suggesting that the effect of BMP-4 on FSH secretion is due to the activation of the BMPs signaling pathway. Furthermore, BMP-4 blocked the stimulatory effect of activin on both FSH release and FSHβ mRNA and amplified the suppression of FSH release and FSHβ mRNA levels induced by 17β-estradiol. These results indicate that a functional BMP system operates within the sheep pituitary, at least in vitro, to decrease FSH release and to modulate the effect of activin.

Patterns of immediate early gene mRNA expression following rodent and human traumatic brain injury

1999 ◽  
Vol 21 (3) ◽  
pp. 234-242 ◽  
Author(s):  
Steven A. Dutcher ◽  
Bill D. Underwood ◽  
Paul D. Walker ◽  
Fernando G. Diaz ◽  
Daniel B. Michael
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Mrna Expression ◽  
Immediate Early Gene ◽  
Early Gene ◽  
Immediate Early ◽  
Gene Mrna

scholarly journals Regulation of Rat Mesangial Cell Migration by Platelet-Derived Growth Factor, Angiotensin II, and Adrenomedullin

1999 ◽  
Vol 10 (12) ◽  
pp. 2495-2502 ◽  
Author(s):  
MASAKAZU KOHNO ◽  
KENICHI YASUNARI ◽  
MIEKO MINAMI ◽  
HIROAKI KANO ◽  
KENSAKU MAEDA ◽  
...  
Keyword(s):  
Cell Migration ◽  
Angiotensin Ii ◽  
Growth Factor ◽  
Mesangial Cell ◽  
Mesangial Cells ◽  
Inhibitory Effect ◽  
Platelet Derived Growth Factor ◽  
Dependent Manner ◽  
Glomerular Mesangial Cells ◽  
Concentration Dependent Manner

Abstract. This study sought to determine whether platelet-derived growth factor (PDGF) and angiotensin II (AngII) stimulate migration of cultured rat glomerular mesangial cells. After finding that this was so, the effects of adrenomedullin (ADM) and cAMP-elevating agents on basal and stimulated mesangial cell migration were examined. Two isoforms of PDGF, AB and BB, stimulated migration in a concentration-dependent manner between 1 and 50 ng/ml, while the AA isoform lacked significant effect. AngII modestly but significantly stimulated migration in a concentration-dependent manner between 10-7 and 10-6 mol/L. Rat ADM significantly inhibited the PDGF BB- and AngII-stimulated migration in a concentration-dependent manner between 10-8 and 10-7 mol/L. Inhibition by rat ADM was accompanied by an increase in cellular cAMP. cAMP agonists or inducers such as 8-bromo cAMP, forskolin, and prostaglandin I2 also significantly reduced the stimulated migration. H 89, a protein kinase A (PKA) inhibitor, attenuated the inhibitory effect of ADM, and a calcitonin gene-related peptide (CGRP) receptor antagonist, human CGRP (8-37), abolished the inhibitory effects of rat ADM. These results suggest that PDGF AB and BB as well as AngII stimulate rat mesangial cell migration and that ADM can inhibit PDGF BB- and AngII-stimulated migration, at least in part through cAMP-dependent mechanisms likely to involve specific ADM receptors with which CGRP interacts. The adenylate cyclase/cAMP/PKA system may be involved in the migration-inhibitory effect of ADM in these cells.

scholarly journals Interference of the Simian Virus 40 Origin of Replication by the Cytomegalovirus Immediate Early Gene Enhancer: Evidence for Competition of Active Regulatory Chromatin Conformation in a Single Domain

2000 ◽  
Vol 20 (11) ◽  
pp. 4062-4074 ◽  
Author(s):  
Peng-Hui Chen ◽  
Wen-Bin Tseng ◽  
Yi Chu ◽  
Ming-Ta Hsu
Keyword(s):  
Dna Replication ◽  
Simian Virus 40 ◽  
Inhibitory Effect ◽  
Simian Virus ◽  
Early Gene ◽  
Dependent Manner ◽  
Gene Enhancer ◽  
Sv40 Origin ◽  
Cmv Enhancer ◽  
Dose Dependent

ABSTRACT Replication origins are often found closely associated with transcription regulatory elements in both prokaryotic and eukaryotic cells. To examine the relationship between these two elements, we studied the effect of a strong promoter-enhancer on simian virus 40 (SV40) DNA replication. The human cytomegalovirus (CMV) immediate early gene enhancer-promoter was found to exert a strong inhibitory effect on SV40 origin-based plasmid replication in Cos-1 cells in a position- and dose-dependent manner. Deletion analysis indicated that the effect was exerted by sequences located in the enhancer portion of the CMV sequence, thus excluding the mechanism of origin occlusion by transcription. Insertion of extra copies of the SV40 origin only partially alleviated the inhibition. Analysis of nuclease-sensitive cleavage sites of chromatin containing the transfected plasmids indicate that the chromatin was cleaved at one of the regulatory sites in the plasmids containing more than one regulatory site, suggesting that only one nuclease-hypersensitive site existed per chromatin. A positive correlation was found between the degree of inhibition of DNA replication and the decrease of P1 cleavage frequency at the SV40 origin. The CMV enhancer was also found to exhibit an inhibitory effect on the CMV enhancer-promoter driving chloramphenicol acetyltransferase expression in a dose-dependent manner. Together these results suggest that inhibition of SV40 origin-based DNA replication by the CMV enhancer is due to intramolecular competition for the formation of active chromatin structure.

Cadmium and platinum suppression of erythropoietin production in cell culture: clinical implications

Blood ◽  
2000 ◽  
Vol 96 (12) ◽  
pp. 3743-3747 ◽  
Author(s):  
Hyogo Horiguchi ◽  
Fujio Kayama ◽  
Etsuko Oguma ◽  
William G. Willmore ◽  
Pavel Hradecky ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Cell Damage ◽  
Hepatoma Cell ◽  
Inhibitory Effect ◽  
Binding Activity ◽  
Hepatoma Cell Line ◽  
Dependent Manner ◽  
Toxic Exposure ◽  
Human Hepatoma Cell ◽  
Simultaneous Exposure

Both toxic exposure to cadmium and cancer therapy with cisplatin (CDDP) can induce anemia in patients owing to the insufficient production of erythropoietin (EPO). Therefore, the effects of cadmium chloride (Cd) and CDDP in the Hep3B human hepatoma cell line, which up-regulates EPO expression in response to hypoxia and cobalt (Co), were investigated. The induction of binding activity of the HIF-1 transcription factor and EPO mRNA expression and protein production were suppressed by Cd and CDDP in a dose-dependent manner with no apparent cell damage. Mercuric chloride also suppressed hypoxia- and Co-induced EPO production, mRNA expression, and HIF-1 binding in a manner similar to Cd and CDDP, whereas zinc chloride suppressed Co-induced EPO production, mRNA expression, and HIF-1 binding but did not affect hypoxia induction or that observed after simultaneous exposure to hypoxia and Co. In contrast, lead and tin salts had no effect on HIF-1 activation or EPO expression. These results indicate that Cd and CDDP have a strong and specific inhibitory effect on hypoxia- and Co-induced signaling and EPO induction in hepatic cells. It is likely that these agents cause anemia by directly impacting EPO production in the kidney.

scholarly journals Central Resistin Regulates Hypothalamic and Peripheral Lipid Metabolism in a Nutritional-Dependent Fashion

Endocrinology ◽  
2008 ◽  
Vol 149 (9) ◽  
pp. 4534-4543 ◽  
Author(s):  
María J. Vázquez ◽  
C. Ruth González ◽  
Luis Varela ◽  
Ricardo Lage ◽  
Sulay Tovar ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Lipid Metabolism ◽  
Mrna Expression ◽  
Fatty Acid Synthase ◽  
De Novo ◽  
Acid Synthesis ◽  
Inhibitory Effect ◽  
De Novo Lipogenesis ◽  
Dependent Manner ◽  
Fed State

Evidence suggests that the adipocyte-derived hormone resistin (RSTN) directly regulates both feeding and peripheral metabolism through, so far, undefined hypothalamic-mediated mechanisms. Here, we demonstrate that the anorectic effect of RSTN is associated with inappropriately decreased mRNA expression of orexigenic (agouti-related protein and neuropeptide Y) and increased mRNA expression of anorexigenic (cocaine and amphetamine-regulated transcript) neuropeptides in the arcuate nucleus of the hypothalamus. Of interest, RSTN also exerts a profound nutrition-dependent inhibitory effect on hypothalamic fatty acid metabolism, as indicated by increased phosphorylation levels of both AMP-activated protein kinase and its downstream target acetyl-coenzyme A carboxylase, associated with decreased expression of fatty acid synthase in the ventromedial nucleus of the hypothalamus. In addition, we also demonstrate that chronic central RSTN infusion results in decreased body weight and major changes in peripheral expression of lipogenic enzymes, in a tissue-specific and nutrition-dependent manner. Thus, in the fed state central RSTN is associated with induced expression of fatty acid synthesis enzymes and proinflammatory cytokines in liver, whereas its administration in the fasted state does so in white adipose tissue. Overall, our results indicate that RSTN controls feeding and peripheral lipid metabolism and suggest that hepatic RSTN-induced insulin resistance may be mediated by central activation of de novo lipogenesis in liver.

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