Compensatory renal hypertrophy. I. Evidence for a factor of renal origin inhibiting DNA synthesis

1977 ◽  
Vol 55 (4) ◽  
pp. 839-847 ◽  
Author(s):  
J. Martel-Pelletier ◽  
M. Bergeron
Keyword(s):  
Molecular Weight ◽  
Dna Synthesis ◽  
Specific Inhibitor ◽  
Inhibitory Effect ◽  
Compensatory Hypertrophy ◽  
Partial Purification ◽  
Dna Uptake ◽  
Renal Hypertrophy ◽  
Compensatory Renal Hypertrophy

This study describes a method for the measurement and partial purification of a factor seemingly involved in the regulation of the renal mass.After homogenization at 4 °C, rabbit kidneys were centrifuged for 100 min at 105 000 g. The resulting supernatant (S-105) was lyophilized and tested on kidney slices obtained from rats mononephrectomized 48 h previously. We have developed a method based on the inhibition of DNA synthesis to measure the activity of the S-105. Slices of renal cortex, undergoing compensatory hypertrophy, were incubated in vitro in Hanks' medium at 37 °C, pH 7.4, in an O2–CO2 atmosphere in the presence of 0.144 μg (20 μCi (1 Ci = 37 GBq)) [3H]thymidine.An inhibition of DNA uptake of [3H]thymidine was noted in the presence of S-105. When other media (Hanks', sucrose, water) were used to extract S-105, the same type of inhibition was noted even though the sucrose buffer seemed ideal for the preservation of the inhibitory factor. The inhibitory effect was still observed after dialysis of S-105 against membranes permitting exclusion of molecules with molecular weight smaller than about 4000 (such as electrolytes and tissue thymidine). This inhibition seems to be specific, since other tissues such as liver in regeneration and rat intestine were not influenced by the dialyzed renal S-105. The dialyzable fraction did contain some inhibitors, but they were not specific for the kidney since they also acted on the liver and the jejunum.Our results suggest the existence, in the normal nephron, of a specific inhibitor of thymidine incorporation into DNA of kidneys undergoing a compensatory hypertrophy. This renal factor has a molecular weight of over 5000.

scholarly journals Degradation of Myogenic Transcription Factor MyoD by the Ubiquitin Pathway In Vivo and In Vitro: Regulation by Specific DNA Binding

1998 ◽  
Vol 18 (10) ◽  
pp. 5670-5677 ◽  
Author(s):  
Ossama Abu Hatoum ◽  
Shlomit Gross-Mesilaty ◽  
Kristin Breitschopf ◽  
Aviad Hoffman ◽  
Hedva Gonen ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Specific Inhibitor ◽  
Inhibitory Effect ◽  
26S Proteasome ◽  
Intact Cells ◽  
Free System ◽  
Ubiquitin System

ABSTRACT MyoD is a tissue-specific transcriptional activator that acts as a master switch for skeletal muscle differentiation. Its activity is induced during the transition from proliferating, nondifferentiated myoblasts to resting, well-differentiated myotubes. Like many other transcriptional regulators, it is a short-lived protein; however, the targeting proteolytic pathway and the underlying regulatory mechanisms involved in the process have remained obscure. It has recently been shown that many short-lived regulatory proteins are degraded by the ubiquitin system. Degradation of a protein by the ubiquitin system proceeds via two distinct and successive steps, conjugation of multiple molecules of ubiquitin to the target protein and degradation of the tagged substrate by the 26S proteasome. Here we show that MyoD is degraded by the ubiquitin system both in vivo and in vitro. In intact cells, the degradation is inhibited by lactacystin, a specific inhibitor of the 26S proteasome. Inhibition is accompanied by accumulation of high-molecular-mass MyoD-ubiquitin conjugates. In a cell-free system, the proteolytic process requires both ATP and ubiquitin and, like the in vivo process, is preceded by formation of ubiquitin conjugates of the transcription factor. Interestingly, the process is inhibited by the specific DNA sequence to which MyoD binds: conjugation and degradation of a MyoD mutant protein which lacks the DNA-binding domain are not inhibited. The inhibitory effect of the DNA requires the formation of a complex between the DNA and the MyoD protein. Id1, which inhibits the binding of MyoD complexes to DNA, abrogates the effect of DNA on stabilization of the protein.

scholarly journals Specific activation of p85-p110 phosphatidylinositol 3'-kinase stimulates DNA synthesis by ras- and p70 S6 kinase-dependent pathways.

1997 ◽  
Vol 17 (1) ◽  
pp. 248-255 ◽  
Author(s):  
J McIlroy ◽  
D Chen ◽  
C Wjasow ◽  
T Michaeli ◽  
J M Backer
Keyword(s):  
Dna Synthesis ◽  
Affinity Purification ◽  
Specific Inhibitor ◽  
Brdu Incorporation ◽  
Glutathione S Transferase ◽  
Intact Cells ◽  
S6 Kinase ◽  
P70 S6 Kinase ◽  
Quiescent Cells

We have developed a polyclonal antibody that activates the heterodimeric p85-p110 phosphatidylinositol (PI) 3'-kinase in vitro and in microinjected cells. Affinity purification revealed that the activating antibody recognized the N-terminal SH2 (NSH2) domain of p85, and the antibody increased the catalytic activity of recombinant p85-p110 dimers threefold in vitro. To study the role of endogenous PI 3'-kinase in intact cells, the activating anti-NSH2 antibody was microinjected into GRC + LR73 cells, a CHO cell derivative selected for tight quiescence during serum withdrawal. Microinjection of anti-NSH2 antibodies increased bromodeoxyuridine (BrdU) incorporation fivefold in quiescent cells and enhanced the response to serum. These data reflect a specific activation of PI 3'-kinase, as the effect was blocked by coinjection of the appropriate antigen (glutathione S-transferase-NSH2 domains from p85 alpha), coinjection of inhibitory anti-p110 antibodies, or treatment of cells with wortmannin. We used the activating antibodies to study signals downstream from PI 3'-kinase. Although treatment of cells with 50 nM rapamycin only partially decreased anti-NSH2-stimulated BrdU incorporation, coinjection with an anti-p70 S6 kinase antibody effectively blocked anti-NSH2-stimulated DNA synthesis. We also found that coinjection of inhibitory anti-ras antibodies blocked both serum- and anti-NSH2-stimulated BrdU incorporation by approximately 60%, and treatment of cells with a specific inhibitor of MEK abolished antibody-stimulated BrdU incorporation. We conclude that selective activation of physiological levels of PI 3'-kinase is sufficient to stimulate DNA synthesis in quiescent cells. PI 3'-kinase-mediated DNA synthesis requires both p70 S6 kinase and the P21ras/MEK pathway.

scholarly journals The protective role of microRNA-21 against coxsackievirus B3 infection through targeting the MAP2K3/P38 MAPK signaling pathway

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Feng He ◽  
Zonghui Xiao ◽  
Hailan Yao ◽  
Sen Li ◽  
Miao Feng ◽  
...  
Keyword(s):  
P38 Mapk ◽  
Cell Apoptosis ◽  
Specific Inhibitor ◽  
Inhibitory Effect ◽  
Mapk Signaling ◽  
Apoptosis Rate ◽  
Cvb3 Infection ◽  
Interfering Rna

Abstract Background The P38 mitogen-activated protein kinase (MAPK) pathway plays an essential role in CVB3-induced diseases. We previously demonstrated microRNA-21 has potential inhibitory effect on the MAP2K3 which locates upstream of P38 MAPK and was upregulated in mouse hearts upon CVB3 infection. However, the effect and underlying mechanism of miRNA-21 on CVB3 infection remain unclear. Methods We detected continuous changes of cellular miRNA-21 and P38 MAPK proteins expression profiling post CVB3 infection in vitro within 12 h. P38 MAPK signaling was inhibited by the specific inhibitor, small interfering RNA and miRNA-21 mimic in vitro, CVB3 replication, cell apoptosis rate and proliferation were detected. Viral load in the mice heart, cardiomyocyte apoptosis rate and histological of the heart were also detected in the mice model of viral myocarditis pretreated with miRNA-21-lentivirus. Results We observed significant upregulation of miRNA-21 expression followed by suppression of the MAP2K3/P38 MAPK signaling in CVB3-infected Hela cells. The inactivation of the MAP2K3/P38 MAPK signaling by P38 MAPK specific inhibitor, small interfering RNA against MAP2K3, or miRNA-21 overexpression significantly inhibited viral progeny release from CVB3-infected cells. Mechanistically, when compared with control miRNA, miRNA-21 showed no effect on capsid protein VP1 expression and viral load within host cells, while significantly reversing CVB3-induced caspase-3 activation and cell apoptosis rate, further promoting proliferation of infected cells, which indicates the inhibitory effect of miRNA-21 on CVB3 progeny release. In the in vivo study, when compared with control miRNA, miRNA-21 pretreatment remarkably inactivated the MAP2K3/P38 MAPK signaling in mice and protected them against CVB3 infection as evidenced by significantly alleviated cell apoptosis rate, reduced viral titers, necrosis in the heart as well as by remarkably prolonged survival time. Conclusions miRNA-21 were reverse correlated with P38 MAPK activation post CVB3 infection, miRNA-21 overexpression significantly inhibited viral progeny release and decreased myocytes apoptosis rate in vitro and in vivo, suggesting that miRNA-21 may serve as a potential therapeutic agent against CVB3 infection through targeting the MAP2K3/P38 MAPK signaling.

scholarly journals Conservation of ribosomal RNA during compensatory renal hypertrophy. A major mechanism in RNA accretion.

1976 ◽  
Vol 69 (3) ◽  
pp. 548-556 ◽  
Author(s):  
W T Melvin ◽  
A Kumar ◽  
R A Malt
Keyword(s):  
Ribosomal Rna ◽  
Cultured Cells ◽  
Compensatory Hypertrophy ◽  
Mouse Kidney ◽  
Average Increase ◽  
Renal Hypertrophy ◽  
Major Mechanism ◽  
Compensatory Renal Hypertrophy

After removal of one mouse kidney, compensatory hypertrophy in the remaining kidney is marked in 2 days by a 20% average increase in ribosomal RNA (rRNA) per cell. Both 28S and 18S RNA are conserved during the initial stages of compensatory renal hypertrophy to an extent sufficient to account for the rest of the observed accumulation of rRNA. Like some cultured cells, the kidney conserves rRNA during physiological growth.

scholarly journals THE DEGREE OF COMPENSATORY RENAL HYPERTROPHY FOLLOWING UNILATERAL NEPHRECTOMY

1938 ◽  
Vol 67 (4) ◽  
pp. 515-519 ◽  
Author(s):  
Lois L. MacKay ◽  
T. Addis ◽  
Eaton M. MacKay
Keyword(s):  
Protein Intake ◽  
Compensatory Hypertrophy ◽  
Unilateral Nephrectomy ◽  
Albino Rats ◽  
Renal Hypertrophy ◽  
Young Rats ◽  
Compensatory Renal Hypertrophy ◽  
Old Rats

Compensatory hypertrophy of the kidney in albino rats is increased by an increase in the protein intake. The effect is greater in old rats than young rats. Successive increases in the protein intake are followed by a reduction in the increase in the degree of compensatory renal hypertrophy.

scholarly journals Involvement of Cyclic Adenosine 3′,5′-Monophosphate in the Differential Regulation of Activin βA and βB Expression by Gonadotropin in the Zebrafish Ovarian Follicle Cells

Endocrinology ◽  
2003 ◽  
Vol 144 (2) ◽  
pp. 491-499 ◽  
Author(s):  
Yajun Wang ◽  
Wei Ge
Keyword(s):  
Oocyte Maturation ◽  
Ovarian Follicle ◽  
Mrna Level ◽  
Specific Inhibitor ◽  
Inhibitory Effect ◽  
Differential Regulation ◽  
Follicle Cells ◽  
Intracellular Camp ◽  
Dependent Manner

Activin is a dimeric protein consisting of two similar but distinct β-subunits, βA and βB. In our previous studies, both activin A (βAβA) and activin B (βBβB) have been demonstrated to stimulate oocyte maturation and promote oocyte maturational competence in the zebrafish. Follistatin, a specific activin-binding protein, can block both activin- and gonadotropin-induced final oocyte maturation in vitro, suggesting that activin is likely a downstream mediator of gonadotropin actions in the zebrafish ovary. In the present study, a full-length cDNA encoding zebrafish ovarian activin βA was cloned and sequenced. The precursor of zebrafish activin βA consists of 395 amino acids and its mature region exhibits about 78% homology with that of mammals. Using an in vitro primary culture of the ovarian follicle cells and semiquantitative RT-PCR assays, we examined the regulation of activin βA and βB expression by human chorionic gonadotropin (hCG) and its intracellular signal transduction mechanisms. hCG (15 IU/ml) increased the mRNA level of activin βA-subunit; however, it significantly down-regulated the steady-state expression level of activin βB in a time- and dose-dependent manner. The differential regulation of the two β-subunits by hCG could be mimicked by 3-isobutyl-1-methylxanthine, forskolin, and dibutyryl-cAMP, suggesting involvement of the intracellular cAMP pathway. Interestingly, H89 (a specific inhibitor of protein kinase A, PKA) could effectively block hCG- and forskolin-stimulated activin βA expression at 10 μm, but it was unable to reverse the inhibitory effects of hCG and forskolin on βB expression. This suggests that the hCG-stimulated activin βA expression is dependent on the activation of the cAMP-PKA pathway, whereas the inhibitory effect of hCG on activin βB expression is likely mediated by PKA-independent pathway(s).

Prostacyclin: Production by Vascular Endothelium and Effects on Platelet Aggregation

1979 ◽  
Author(s):  
S. Moncada ◽  
S. Bunting
Keyword(s):  
Endothelial Cells ◽  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Vascular Endothelium ◽  
Vascular Endothelial Cells ◽  
Specific Inhibitor ◽  
Inhibitory Effect ◽  
Vascular Endothelial ◽  
Prostacyclin Production

The inhibitory effect of vascular endothelial cells on platelet aggregation is due to their ability to release prostacyclin. The existence of an ADPase has been confirmed in endothelial cells but this enzymes does not seem to be related to the anti-aggregating properties of vascular endothelium. In vitro, the release of prostacyclin by humand and rabbit endothelial cells persists after several subcultures. The production of PGI2 can be demonstrated by its inhibition by aspirin-like drugs or 15-hydroperoxy arachidonic acid (a specific inhibitor of PGI2 synthesis). Moreover, the antiaggregating activity is antagonised by an antibody to 5,6 dihydro prostacyclin which cross reacts and neutralises prostacyclin.

Aldosterone-induced proteins: characterization using lectin-affinity chromatography

1985 ◽  
Vol 249 (3) ◽  
pp. C215-C225 ◽  
Author(s):  
B. Blazer-Yost ◽  
M. Cox
Keyword(s):  
Molecular Weight ◽  
Affinity Chromatography ◽  
Concanavalin A ◽  
Specific Inhibitor ◽  
Partial Purification ◽  
Toad Urinary Bladder ◽  
Lectin Affinity Chromatography ◽  
Na Transport ◽  
Electrophoretic Polymorphism ◽  
Induced Proteins

Aldosterone-stimulated Na+ transport in toad urinary bladder is associated with the synthesis of a specific group of proteins whose induction appears to be related to the natriferic effect of the hormone. These aldosterone-induced proteins (AIPs) occur in two slightly different molecular weight classes (around 70 kDa), each class being composed of several proteins with discrete isoelectric points (range, 5.5-6.0). Because glycosylation is a common cause of such electrophoretic polymorphism and microheterogeneity, we examined whether these proteins are glycoproteins. Tunicamycin (a specific inhibitor of N-linked glycosylation) inhibited aldosterone-stimulated Na+ transport and AIP synthesis without affecting overall protein synthesis. The vast majority of epithelial cell proteins did not bind to the mannose-specific lectin, concanavalin A-sepharose. In contrast, both classes of AIPs bound to concanavalin A-sepharose, but the affinities of the higher and lower molecular weight proteins were markedly different: the former were readily eluted with 0.2 M alpha-methyl-D-mannoside alone, whereas the latter could only be eluted with 0.4 M alpha-methyl-D-mannoside in combination with high concentrations of NaCl (2.5-5.0 M). These studies indicate that 1) glycosylation is important in the natriferic response to aldosterone, 2) the AIPs are N-linked mannose-containing glycoproteins, and 3) the electrophoretic polymorphism of the AIPs is due, at least in part, to differences in glycosylation. Furthermore, concanavalin A-affinity chromatography provides a simple means for the partial purification of these putative "effectors" of the cellular action of aldosterone.

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