Contribution of a 12 kDa protein to the angiotensin II-induced stabilization of angiotensinogen mRNA: interaction with the 3′ untranslated mRNA

1995 ◽  
Vol 14 (2) ◽  
pp. 209-226 ◽  
Author(s):  
C Klett ◽  
M Bader ◽  
M Schwemmle ◽  
D Ganten ◽  
E Hackenthal
Keyword(s):  
Angiotensin Ii ◽  
Molecular Mass ◽  
Half Life ◽  
Rna Binding ◽  
Ex Vivo ◽  
Cross Link ◽  
Band Shift ◽  
Incubation System ◽  
A Cell

ABSTRACT Several authors have shown that angiotensin II stimulates hepatic angiotensinogen synthesis in vivo, ex vivo and in vitro. In previous studies we have demonstrated that this effect of angiotensin II depends mainly on a transient inhibition of adenylyl cyclase and is the consequence of a stabilization of angiotensinogen mRNA. In the present study we describe the isolation of a polysomal 12 kDa protein which, in band shift and cross link assays, shows a specific affinity to the 3′ untranslated region (3′ UTR) of angiotensinogen mRNA and prevents enzymatic degradation of angiotensinogen mRNA in a cell-free incubation system. [32P]UTP-labelled or unlabelled 3′ fragments of angiotensinogen mRNA were synthesized on a transcription vector (pGEM5zf+) into which the corresponding DNA sequence was cloned after restriction from vector pRAG 16. Binding of the 12 kDa protein to the radioactively labelled 3′ UTR of angiotensinogen mRNA could be displaced by unlabelled 3′ UTR mRNA fragments but not by a renin mRNA of comparable length derived from the coding region, The RNA-binding protein appears to be derived from a higher molecular mass precursor (45 kDa) which is preferentially present under reducing conditions in vitro; the active low molecular mass form is evident in the absence of reducing agents. In a cross link experiment we established that a band shift signal which was obtained in the presence of the 45 kDa protein preparation exclusively depends on RNA binding of the active 12 kDa protein. In addition, a phosphorylation step may be involved in the activation of the 12 kDa protein, since its molecular mass and isoelectric point correlate with proteins which were phosphorylated in response to transient decreases of cAMP (induced by guanfacine or angiotensin II) or in response to a direct inhibition of protein kinase A by the cAMP antagonist Rp-cAMP. The importance of phosphorylation reactions for the stabilization of angiotensinogen mRNA was further assessed in a cell-free incubation system of rat liver parenchymal cells. These studies demonstrated that in the presence of acid phosphatase (1 U/ml) the half-life of angiotensinogen was significantly decreased. In the same incubation system the 12 kDa protein increased the half-life of endogenous as well as of exogenous angiotensinogen mRNA three- to fourfold, while no stabilizing effect was apparent when exogenous angiotensinogen mRNA from which the 3′ tail had been deleted was added. We concluded that an intracellular 12 kDa protein may play a crucial role in the angiotensin Il-induced stabilization of hepatic angiotensinogen mRNA and further suggest that this protein exerts its effect via binding to the 3′ UTR of angiotensinogen mRNA in response to a cAMP-dependent activation step.

Collagen fibrous scaffolds for sustained delivery of growth factors for meniscal tissue engineering

Nanomedicine ◽  
2022 ◽  
Author(s):  
Jihye Baek ◽  
Kwang Il Lee ◽  
Ho Jong Ra ◽  
Martin K Lotz ◽  
Darryl D D'Lima
Keyword(s):  
Tissue Engineering ◽  
Growth Factors ◽  
Sustained Release ◽  
Ex Vivo ◽  
Synovial Cell ◽  
Growth Factor Delivery ◽  
Meniscal Tissue ◽  
A Cell

Aim: To mimic the ultrastructural morphology of the meniscus with nanofiber scaffolds coupled with controlled growth factor delivery to modulate cellular performance for tissue engineering of menisci. Methods: The authors functionalized collagen nanofibers by conjugating heparin to the following growth factors for sustained release: PDGF-BB, TGF-β1 and CTGF. Results: Incorporating growth factors increased human meniscal and synovial cell viability, proliferation and infiltration in vitro, ex vivo and in vivo; upregulated key genes involved in meniscal extracellular matrix synthesis; and enhanced generation of meniscus-like tissue. Conclusion: The authors' results indicate that functionalizing collagen nanofibers can create a cell-favorable micro- and nanoenvironment and can serve as a system for sustained release of bioactive factors.

scholarly journals Regulation of cilia abundance in multiciliated cells

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Rashmi Nanjundappa ◽  
Dong Kong ◽  
Kyuhwan Shim ◽  
Tim Stearns ◽  
Steven L Brody ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Surface Area ◽  
Ex Vivo ◽  
Compensatory Mechanism ◽  
Multiciliated Cells ◽  
Culture Model ◽  
A Cell ◽  
Dependent Mechanism

Multiciliated cells (MCC) contain hundreds of motile cilia used to propel fluid over their surface. To template these cilia, each MCC produces between 100-600 centrioles by a process termed centriole amplification. Yet, how MCC regulate the precise number of centrioles and cilia remains unknown. Airway progenitor cells contain two parental centrioles (PC) and form structures called deuterosomes that nucleate centrioles during amplification. Using an ex vivo airway culture model, we show that ablation of PC does not perturb deuterosome formation and centriole amplification. In contrast, loss of PC caused an increase in deuterosome and centriole abundance, highlighting the presence of a compensatory mechanism. Quantification of centriole abundance in vitro and in vivo identified a linear relationship between surface area and centriole number. By manipulating cell size, we discovered that centriole number scales with surface area. Our results demonstrate that a cell-intrinsic surface area-dependent mechanism controls centriole and cilia abundance in multiciliated cells.

Pharmacokinetics, Pharmacodynamics and Tolerability of a Potent, Non-peptidic, GP IIb/IIIa Receptor Antagonist following Multiple Oral Administrations of a Prodrug Form

1998 ◽  
Vol 79 (01) ◽  
pp. 169-176 ◽  
Author(s):  
Nishit Modi ◽  
Sherron Bullens ◽  
Cheryl Pater ◽  
Michael Lipari ◽  
Kirk Robarge ◽  
...  
Keyword(s):  
Half Life ◽  
Rhesus Monkeys ◽  
Ex Vivo ◽  
Active Form ◽  
Plasma Concentrations ◽  
Volume Of Distribution ◽  
A Value ◽  
Terminal Half Life ◽  
The Right

SummaryRo 44-3888 is a potent and selective antagonist of GP IIb/IIIa. Following IV administration to rhesus monkeys, the (mean ± SD.) clear ance, volume of distribution and terminal half-life of Ro 44-3888 were 4.4 ± 1.8 ml/min/kg, 0.8 ± 0.4 l/kg and 2.5 ± 0.8 h respectively. Oral administration of Ro 48-3657 (1 mg/kg), a doubly protected prodrug form, produced peak concentrations of Ro 44-3888 (152 ± 51 ng/ml), 4.2 ± 2.2 h after dosing. Terminal half-life and estimated bioavailabil ity were 5.1 ± 1.6 h and 33 ± 6% respectively. No effect on blood pressure, heart rate or platelet counts were seen. Adenosine diphosohate (ADP) induced platelet aggregation (PA) and cutaneous bleeding times (CBT) were determined prior to and after the last of 8 daily oral administrations of Ro 48-3657 (0.25 or 0.5 mg/kg) to eight rhesus monkeys. Peak and trough plasma concentrations were proportional to dose and steady state was achieved after the second administration. Inhibition of PA and prolongation of CBT were concentration dependent. The ex vivo IC50 (82 nM) for ADP-mediated PA correlated with a value (58 nM) determined in vitro. The CBT response curve was displaced to the right of the PA curve. CBT was prolonged to ≥25 min when levels of Ro 44-3888 exceeded 190 nM and PA was >90% inhibited. Therefore, in rhesus monkeys, Ro 48-3657 is reproducibly absorbed and converted to its active form, is well tolerated, and has a concentration-dependent effect on PA and CBT. These properties make Ro 48-3657 an attractive candidate for evaluation in patients at high risk for arterial thrombosis.

scholarly journals Altered Gag Polyprotein Cleavage Specificity of Feline Immunodeficiency Virus/Human Immunodeficiency Virus Mutant Proteases as Demonstrated in a Cell-Based Expression System

2006 ◽  
Vol 80 (16) ◽  
pp. 7832-7843 ◽  
Author(s):  
Ying-Chuan Lin ◽  
Ashraf Brik ◽  
Aymeric de Parseval ◽  
Karen Tam ◽  
Bruce E. Torbett ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Feline Immunodeficiency Virus ◽  
Ex Vivo ◽  
Expression System ◽  
Immunodeficiency Virus ◽  
A Cell ◽  
Virus Mutant ◽  
Substrate Inhibitor ◽  
Hiv 1

ABSTRACT We have used feline immunodeficiency virus (FIV) protease (PR) as a mutational system to study the molecular basis of substrate-inhibitor specificity for lentivirus PRs, with a focus on human immunodeficiency virus type 1 (HIV-1) PR. Our previous mutagenesis studies demonstrated that discrete substitutions in the active site of FIV PR with structurally equivalent residues of HIV-1 PR dramatically altered the specificity of the mutant PRs in in vitro analyses. Here, we have expanded these studies to analyze the specificity changes in each mutant FIV PR expressed in the context of the natural Gag-Pol polyprotein ex vivo. Expression mutants were prepared in which 4 to 12 HIV-1-equivalent substitutions were made in FIV PR, and cleavage of each Gag-Pol polyprotein was then assessed in pseudovirions from transduced cells. The findings demonstrated that, as with in vitro analyses, inhibitor specificities of the mutants showed increased HIV-1 PR character when analyzed against the natural substrate. In addition, all of the mutant PRs still processed the FIV polyprotein but the apparent order of processing was altered relative to that observed with wild-type FIV PR. Given the importance of the order in which Gag-Pol is processed, these findings likely explain the failure to produce infectious FIVs bearing these mutations.

scholarly journals Cell-autonomous FLT3L shedding via ADAM10 mediates conventional dendritic cell development in mouse spleen

2019 ◽  
Vol 116 (29) ◽  
pp. 14714-14723 ◽  
Author(s):  
Kohei Fujita ◽  
Svetoslav Chakarov ◽  
Tetsuro Kobayashi ◽  
Keiko Sakamoto ◽  
Benjamin Voisin ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Embryonic Fibroblasts ◽  
Major Pathway ◽  
Peripheral Tissues ◽  
A Cell ◽  
Membrane Bound ◽  
A Disintegrin And Metalloproteinase ◽  
Ex Vivo Culture ◽  
Culture Supernatants

Conventional dendritic cells (cDCs) derive from bone marrow (BM) precursors that undergo cascades of developmental programs to terminally differentiate in peripheral tissues. Pre-cDC1s and pre-cDC2s commit in the BM to each differentiate into CD8α+/CD103+ cDC1s and CD11b+ cDC2s, respectively. Although both cDCs rely on the cytokine FLT3L during development, mechanisms that ensure cDC accessibility to FLT3L have yet to be elucidated. Here, we generated mice that lacked a disintegrin and metalloproteinase (ADAM) 10 in DCs (Itgax-cre × Adam10-fl/fl; ADAM10∆DC) and found that ADAM10 deletion markedly impacted splenic cDC2 development. Pre-cDC2s accumulated in the spleen with transcriptomic alterations that reflected their inability to differentiate and exhibited abrupt failure to survive as terminally differentiated cDC2s. Induced ADAM10 ablation also led to the reduction of terminally differentiated cDC2s, and restoration of Notch signaling, a major pathway downstream of ADAM10, only modestly rescued them. ADAM10∆DC BM failed to generate cDC2s in BM chimeric mice with or without cotransferred ADAM10-sufficient BM, indicating that cDC2 development required cell-autonomous ADAM10. We determined cDC2s to be sources of soluble FLT3L, as supported by decreased serum FLT3L concentration and the retention of membrane-bound FLT3L on cDC2 surfaces in ADAM10∆DC mice, and by demonstrating the release of soluble FLT3L by cDC2 in ex vivo culture supernatants. Through in vitro studies utilizing murine embryonic fibroblasts, we determined FLT3L to be a substrate for ADAM10. These data collectively reveal cDC2s as FLT3L sources and highlight a cell-autonomous mechanism that may enhance FLT3L accessibility for cDC2 development and survival.

An A + U-rich element RNA-binding factor regulates c-myc mRNA stability in vitro

1991 ◽  
Vol 11 (5) ◽  
pp. 2460-2466 ◽  
Author(s):  
G Brewer
Keyword(s):  
Cellular Response ◽  
Mrna Decay ◽  
Rna Binding ◽  
Binding Capacity ◽  
Proteinase K ◽  
Rapid Turnover ◽  
A Cell ◽  
Degradation Activity ◽  
Proteinase K Treatment

Transient expression of some proto-oncogenes, cytokines, and transcription factors occurs as a cellular response to growth factors, 12-O-tetradecanoylphorbol-13-acetate, antigen stimulation, or inflammation. Expression of these genes is mediated in part by the rapid turnover of their mRNAs. A + U-rich elements in the 3' untranslated regions of these mRNAs serve as one recognition signal targeting the mRNAs for rapid degradation. I report the identification of a cytosolic factor that both binds to the proto-oncogene c-myc A + U-rich element and specifically destabilizes c-myc mRNA in a cell-free mRNA decay system which reconstitutes mRNA decay processes found in cells. Proteinase K treatment of the factor abolishes its c-myc mRNA degradation activity without affecting its RNA-binding capacity. Thus, RNA substrate binding and degradation appear to be separable functions. These findings should aid in understanding how the cell selectively targets mRNAs for rapid turnover.

scholarly journals An RNA-binding protein specifically interacts with a functionally important domain of the downstream element of the simian virus 40 late polyadenylation signal.

1991 ◽  
Vol 11 (10) ◽  
pp. 5312-5320 ◽  
Author(s):  
Z W Qian ◽  
J Wilusz
Keyword(s):  
Binding Site ◽  
Rna Binding ◽  
Specific Binding ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Polyadenylation Signal ◽  
Band Shift

We have identified an RNA-binding protein which interacts with the downstream element of the simian virus 40 late polyadenylation signal in a sequence-specific manner. A partially purified 50-kDa protein, which we have named DSEF-1, retains RNA-binding specificity as assayed by band shift and UV cross-linking analyses. RNA footprinting assays, using end-labeled RNA ladder fragments in conjunction with native gel electrophoresis, have identified the DSEF-1 binding site as 5'-GGGGGAGGUGUGGG-3'. This 14-base sequence serves as an efficient DSEF-1 binding site when placed within a GEM4 polylinker-derived RNA. Finally, the DSEF-1 binding site restored efficient in vitro 3' end processing to derivatives of the simian virus 40 late polyadenylation signal in which it substituted for the entire downstream region. DSEF-1, therefore, may be a sequence-specific binding factor which regulates the efficiency of polyadenylation site usage.

scholarly journals Human La protein: a stabilizer of histone mRNA.

1997 ◽  
Vol 17 (6) ◽  
pp. 3028-3036 ◽  
Author(s):  
R S McLaren ◽  
N Caruccio ◽  
J Ross
Keyword(s):  
Half Life ◽  
Mrna Decay ◽  
Rna Binding ◽  
S Phase ◽  
Coding Region ◽  
Histone Mrna ◽  
Histone Proteins ◽  
Unbound Fraction ◽  
Mrna Half Life

Histone mRNA is destabilized at the end of S phase and in cell-free mRNA decay reaction mixtures supplemented with histone proteins, indicating that histones might autoregulate the histone mRNA half-life. Histone mRNA destabilization in vitro requires three components: polysomes, histones, and postpolysomal supernatant (S130). Polysomes are the source of the mRNA and mRNA-degrading enzymes. To investigate the role of the S130 in autoregulation, crude S130 was fractionated by histone-agarose affinity chromatography. Two separate activities affecting the histone mRNA half-life were detected. The histone-agarose-bound fraction contained a histone mRNA destabilizer that was activated by histone proteins; the unbound fraction contained a histone mRNA stabilizer. Further chromatographic fractionation of unbound material revealed only a single protein stabilizer, which was purified to homogeneity, partially sequenced, and found to be La, a well-characterized RNA-binding protein. When purified La was added to reaction mixtures containing polysomes, a histone mRNA decay intermediate was stabilized. This intermediate corresponded to histone mRNA lacking 12 nucleotides from its 3' end and containing an intact coding region. Anti-La antibody blocked the stabilization effect. La had little or no effect on several other cell cycle-regulated mRNAs. We suggest that La prolongs the histone mRNA half-life during S phase and thereby increases histone protein production.

Characterization of an insect ferritin subunit synthesized in a cell-free system

1990 ◽  
Vol 68 (7-8) ◽  
pp. 1005-1011 ◽  
Author(s):  
C. A. Ketola-Pirie
Keyword(s):  
Molecular Mass ◽  
Proteinase K ◽  
Translation Product ◽  
Western Blots ◽  
Free System ◽  
Cell Free System ◽  
A Cell ◽  
Vacuolar System

Ferritin, an iron-sequestering and -binding protein, is localized to the vacuolar system in Calpodes ethlius larvae. The amount of iron-loaded ferritin in intact larval midgut can be increased by pretreatment with iron. When poly(A)+ RNA from control or iron-treated larvae was translated in vitro, a 24 kilodalton (kDa) protein was a major translation product. If the cell-free system was supplemented with dog pancreatic microsomes, the 24-kDa protein was not detectable: the major translation product was 28–30 kDa. The 24-kDa and 28- to 30-kDa proteins were identified as ferritin subunits by immunoprecipitation with anti-Manduca ferritin antibodies. Proteinase K digestion of the translation products showed that the 28- to 30-kDa subunit was targeted into the lumen of, and protected by, the microsomes. The change in molecular mass of the ferritin monomer was attributed to glycosylation of the 24-kDa subunit within the lumen of the microsomes. This was demonstrated by (i) the ability of the 28- to 30-kDa subunit, but not the 24-kDa subunit, to bind concanavalin A on Western blots and (ii) inhibition of the change in molecular mass from 24 to 28–30 kDa if tunicamycin is added to the microsomes. The results indicate that the Calpodes ferritin subunit was synthesized, targeted to microsomes, and glycosylated within their lumen in a rabbit reticulocyte cell-free system primed with midgut poly(A)+ RNA extracted from control or iron-treated larvae.Key words: insect ferritin, cell-free synthesis, glycosylation.

scholarly journals GTx011, a Potent Allosteric Modifier of Hemoglobin Oxygen Affinity, Prevents RBC Sickling in Whole Blood and Prolongs RBC Half-Life in Vivo in a Murine Model of Sickle Cell Disease

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 217-217 ◽  
Author(s):  
Kobina Dufu ◽  
Donna Oksenberg ◽  
Chengjing Zhou ◽  
Athiwat Hutchaleelaha ◽  
David R. Archer
Keyword(s):  
Flow Cytometry ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Half Life ◽  
Ex Vivo ◽  
Cell Disease ◽  
Employment Equity ◽  
Hypoxic Conditions ◽  
Equity Ownership

Abstract Sickle cell disease (SCD) is caused by a point mutation in the β-globin gene leading to production of hemoglobin S (HbS) that polymerizes under hypoxic conditions with subsequent formation of sickled red blood cells (RBCs). We have developed a novel small molecule, GTx011, which attains effective concentrations in blood upon oral dosing in multiple species. GTx011 increases the affinity of oxygen (O2) for HbS, delays in vitro HbS polymerization and prevents sickling of isolated RBCs under hypoxic conditions. We report here that GTx011 prevents in vitro sickling of RBCs in blood from sickle cell patients. Moreover, in a murine model of sickle cell disease (Townes SS mice), GTx011 prevents ex vivo sickling of RBCs and prolongs RBC half-life. We previously reported that GTx011 prevents sickling of isolated sickle cell RBCs (SSRBCs) subjected to a fixed hypoxic condition (pO2 of ~30 mm Hg) for 30 min. For a more physiologically relevant evaluation, we determined the anti-sickling activity of GTx011 in blood under variable hypoxic conditions over a shorter duration of time. Sickling of SSRBCs in blood was evaluated using a combination of hemoximetry and morphometric measurements. Whole blood from sickle cell patients was modified in vitro with GTx011 prior to hemoximetry. Conversely, blood from SS mice with GTx011 orally dosed acutely or chronically for 10-12 days was used for hemoximetry. SSRBCs were harvested during hemoximetry at various O2 tensions and immediately fixed in a deoxygenated solution of 2% glutaraldehyde/PBS prior to morphological quantitative analysis with CellVigene software or imaging flow cytometry (AMNIS ImageStreamX MkII). To evaluate the effect of GTx011 on RBC half-life in SS mice, N-hydroxysuccinimide biotin was injected into SS mice on day 5 of chronic dosing, producing a pulse-label. Flow cytometry was performed using fluorescently labeled streptavidin to determine the decay of biotinylation and RBC half-life. Reticulocyte counts were measured at different intervals during the dosing regimen by determining the percentage of blood cells that were Ter-119+, Thiazole-Orange+ and CD45- by flow cytometry. In a dose-dependent manner, GTx011 decreased the p50 value of human blood indicating an increase in Hb-O2 affinity. In parallel, GTx011 dose-dependently reduced the number of sickled SSRBCs under all hypoxic conditions (pO2 of <40 mm Hg) evaluated. Moreover, at an O2 tension mimicking typical hypoxic conditions in tissue capillaries (40 mm Hg), 300 µM of GTx011 was sufficient to prevent sickling of human SSRBCs in whole blood (20% Hct). Similarly, ex vivo sickling analysis indicated that, relative to blood from vehicle-treated SS mice, blood from GTx011-treated SS mice showed a pronounced reduction in the number of sickled RBCs under hypoxic conditions with a concurrent reduction in p50. For example, at a pO2 of 10 mm Hg, 19% of SSRBCs in blood from GTx011-treated mice sickled ex vivo compared with 56% in blood from vehicle-treated SS mice. In SS mice chronically dosed with GTx011, a prolongation of the RBC half-life from 2.4 days to 3.8 days was achieved together with a marked decrease in reticulocyte count. This increase in RBC half-life and accompanying reduction in reticulocyte count was observed in mice with GTx011 concentrations in blood that corresponded to >30% calculated Hb target occupancy. Taken together, these data suggest that GTx011 has the potential to be a beneficial therapeutic agent for the chronic treatment of SCD. Table SS mice RBC half life Reticulocytes Sickled RBCs Hemoximetry Chronic treatment, PO, BID, 10-12 days (Days) (%) (% at 10 mm Hg) p20 (mm Hg) p50 (mm Hg) Vehicle-treated 2.4 53 56 18 32 GBT440-treated (100mg/kg) 3.8 32 19 4.5 21 Disclosures Dufu: Global Blood Therapeutics: Employment, Equity Ownership. Oksenberg:Global Blood Therapeutics: Employment, Equity Ownership. Zhou:Global Blood Therapeutics: Research Funding. Hutchaleelaha:Global Blood Therapeutics: Employment, Equity Ownership. Archer:Global Blood Therapeutics: Consultancy, Research Funding.

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