Serotonin and MAOA enable the organizer and tip dominance in Dictyostelium

Mapping Intimacies ◽

10.21203/rs.3.rs-150066/v1 ◽

2021 ◽

Author(s):

Ramamurthy Baskar ◽

Rakesh Mani ◽

Geoffrey Hyde

Keyword(s):

Cell Adhesion ◽

Rna Interference ◽

Molecular Techniques ◽

Monoamine Oxidase A ◽

Dependent Manner ◽

Serotonin Antagonist ◽

And Function ◽

Tip Formation ◽

Dose Dependent ◽

Specific Inhibitors

Abstract The embryonic organizer is essential to determine one or more developmental polarities during chordate early development1,2. Functionally similar organizers also occur in more ancient animals3, and even in some protozoans such as Dictyostelium, in which the tip of the multicellular mound acts as an organizer4, establishing the main developmental axis, and regulating the size of the fruiting body5. However, our understanding of how the Dictyostelium organizer arises, and functions, is limited. Here we show that monoamine oxidase A (maoA), which degrades serotonin, confers the fate of an organizer to the Dictyostelium tip. Conversely, once a tip has formed, serotonin contributes to tip dominance. It inhibits further tip formation, and thus ensures the mound retains the size specified during an earlier developmental stage. Reducing the expression of maoA through RNA interference or by adding MAO specific inhibitors suppresses tip formation. Conversely, adding human MAOA enzyme, or an antagonist or antibodies against serotonin, restores tip formation in maoA knockdowns. Overexpression of maoA or adding a serotonin antagonist to the wildtype induces multiple tips from a single mound in a dose dependent manner. Using an array of genetic and molecular techniques, we show that serotonin’s inhibition of cAMP signalling and cell-cell adhesion is the basis of its regulation of tip formation. Our study demonstrates that serotonin, recently appreciated for its developmental roles in widespread phyla6, also has a novel and ancient role in the formation and function of an organizer.

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ROLE OF PLATELET GLYCOPROTEINS lb AND llb/llla IN TUMOR CELL INDUCED PLATELET AGGREGATION AND TUMOR CELL ADHESION TO EXTRACELLULAR MATRIX. I. Grossi

10.1055/s-0038-1644670 ◽

1987 ◽

Author(s):

L Grossi ◽

K V Honn ◽

B F Sloane ◽

J Thomopson ◽

D Ohannesian ◽

...

Keyword(s):

Extracellular Matrix ◽

Cell Adhesion ◽

Platelet Aggregation ◽

Tumor Cell ◽

Platelet Adhesion ◽

Eicosatetraenoic Acid ◽

Platelet Glycoprotein ◽

Dependent Manner ◽

Tumor Cell Adhesion ◽

Dose Dependent

Platelet glycoproteins are known to play a role in platelet platelet interactions, platelet activation, and platelet adhesion to extracellular matrix (ECM). Monoclonal antibody to human platelet glycoprotein lb (mAblb) and polyclonal antibodies to the llb/llla complex (pAbllb/llla) were used to evaluate the involvement of these glycoproteins in tumor cellinduced platelet aggregation (TCIPA and tumor cell adhesion to the ECM. We have demonstrated that human cervical carcinoma (MS5I7), human colon carcinoma (Clone A), and rat Walker 256 carcinosarcoma (W256) cells induce aggregation of homologous platelets via thrombin generation. MAblb and pAbllb/llla were shown to inhibit TCIPA by MS517, Clone A, and W256 in a dose dependent manner. MAblb was also shown to inhibit platelet thromboxane B2 production in response to tumor cells in a dose dependent manner. Neither mAblb nor pAbllb/llla had any effect on ADP stimulated platelet aggregation. Concentrations of mAblb and pAbllb/llla which produced half maximal inhibition alone were combined resulting in complete inhibition of TCIPA. Preincubation of MS5I7 and W256 with mAblb also resulted in inhibition of TCIPA, while preincubation of Clone A with mAblb did not, suggesting the presence of this glycoprotein on the cell membranes of MS5I7 and W256, but not on Clone A. Immunofluorescence studies confirmed the presence of this glycoprotein on the cell plasma membrane of the MS5I7 and W256, but not on Clone A. Preincubation of MS5I7 and W256 with both mAblb and pAbllb/llla alone or in combination, also resulted in decreased (12S)-12 -hydroxy -5, 8,10, 14 -eicosatetraenoic acid (12-HETE) production, while platelets preincubated with these antibodies had no effect on the concentration of 12-HETE produced. Isolation of platelet membranes and released platelet contentswere tested separately and in combination on platelet adhesion to ECM. Platelet release factors were ineffective, while isolated platelet membrane ghosts enhanced adhesion. Disruption of the platelet cytoskeleton andinhibition of the formation of the llb/llla complex decreased platelet enhanced tumor cell adhesion. These findings suggest a role for these platelet glycoproteins in TCIPA, platelet enhanced tumor cell adhesion to ECM and subsequent tumor metastasis.

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Visualization of a Cytoskeleton-like Ftsz Network in Chloroplasts

The Journal of Cell Biology ◽

10.1083/jcb.151.4.945 ◽

2000 ◽

Vol 151 (4) ◽

pp. 945-950 ◽

Cited By ~ 67

Author(s):

Justine Kiessling ◽

Sven Kruse ◽

Stefan A. Rensing ◽

Klaus Harter ◽

Eva L. Decker ◽

...

Keyword(s):

Life Sciences ◽

Dependent Manner ◽

Bacterial Cell Division ◽

Subcellular Structure ◽

Form And Function ◽

Intron Structure ◽

Division Process ◽

Eukaryotic Organisms ◽

And Function ◽

Dose Dependent

It has been a long-standing dogma in life sciences that only eukaryotic organisms possess a cytoskeleton. Recently, this belief was questioned by the finding that the bacterial cell division protein FtsZ resembles tubulin in sequence and structure and, thus, may be the progenitor of this major eukaryotic cytoskeletal element. Here, we report two nuclear-encoded plant ftsZ genes which are highly conserved in coding sequence and intron structure. Both their encoded proteins are imported into plastids and there, like in bacteria, they act on the division process in a dose-dependent manner. Whereas in bacteria FtsZ only transiently polymerizes to a ring-like structure, in chloroplasts we identified persistent, highly organized filamentous scaffolds that are most likely involved in the maintenance of plastid integrity and in plastid division. As these networks resemble the eukaryotic cytoskeleton in form and function, we suggest the term “plastoskeleton” for this newly described subcellular structure.

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Protective Effect of Pantethine on Experimental Thrombocytopenia in the Rat

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647846 ◽

1975 ◽

Vol 33 (03) ◽

pp. 528-539 ◽

Cited By ~ 2

Author(s):

Shin-ichiro Ashida ◽

Yasushi Abiko

Keyword(s):

Nitrogen Mustard ◽

Experimental Period ◽

Significant Degree ◽

Rabbit Serum ◽

Dependent Manner ◽

Essentially Normal ◽

And Function ◽

Dose Dependent ◽

Platelet Functions

SummaryThe effects of pantethine on circulating platelet counts and platelet functions were studied in normal and experimentally produced thrombocytopenic rats.Administration of pantethine to normal animals did not cause any alterations in both platelet count and function except for a slight enhancement of intravascular platelet aggregation induced by collagen or neuraminidase.Injection of anti-rat platelet rabbit serum into rats resulted in acute thrombocytopenia. Administration of pantethine prior to the antiserum promoted recovery from the thrombocytopenia in a dose dependent manner, but administration of the drug after development of the thrombocytopenia was not effective. A similar result was obtained with a transient thrombocytopenia induced by exchange transfusion with platelet poor blood. Regardless of whether animals were treated with pantethine or not, the platelets newly generated during the course of recovery from thrombocytopenia were essentially normal in the function tested in vitro.A more chronic thrombocytopenia induced by repeated injections of the antiserum was prevented, to some significant degree, by daily administration of pantethine throughout the experimental period.In contrast to these, such effect of pantethine was not observed with the thrombocytopenia models produced by nitrogen mustard N-oxide and neuraminidase.These findings were discussed in relation to mechanism of the action of pantethine and to possible clinical application of the drug to thrombocytopenia.

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Factor XIIIa supports microvascular endothelial cell adhesion and inhibits capillary tube formation in fibrin

Blood ◽

10.1182/blood.v95.8.2586.008k04_2586_2592 ◽

2000 ◽

Vol 95 (8) ◽

pp. 2586-2592

Author(s):

Susan M. Dallabrida ◽

Lisa A. Falls ◽

David H. Farrell

Keyword(s):

Endothelial Cells ◽

Cell Adhesion ◽

Endothelial Cell ◽

Capillary Tube ◽

Coagulation Factor ◽

Tube Formation ◽

Factor Xiiia ◽

Dependent Manner ◽

Dose Dependent ◽

Endothelial Cell Adhesion

Coagulation factor XIIIa is a transglutaminase that catalyzes covalent cross-link formation in fibrin clots. In this report, we demonstrate that factor XIIIa also mediates adhesion of endothelial cells and inhibits capillary tube formation in fibrin. The adhesive activity of factor XIIIa was not dependent on the transglutaminase activity, and did not involve the factor XIIIb-subunits. The adhesion was inhibited by 99% using a combination of monoclonal antibodies directed against integrin vβ3 and β1-containing integrins, and was dependent on Mg2+ or Mn2+. Soluble factor XIIIa also bound to endothelial cells in solution, as detected by flow cytometry. In addition, factor XIIIa inhibited endothelial cell capillary tube formation in fibrin in a dose-dependent manner. Furthermore, the extent of inhibition differed in 2 types of fibrin. The addition of 10 to 100 μg/mL factor XIIIa produced a dose-dependent reduction in capillary tube formation of 60% to 100% in γA/γA fibrin, but only a 10% to 37% decrease in γA/γ′ fibrin. These results show that factor XIIIa supports endothelial cell adhesion in an integrin-dependent manner and inhibits capillary tube formation.

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RNF125 is a Ubiquitin-Protein Ligase that Promotes p53 Degradation

Cellular Physiology and Biochemistry ◽

10.1159/000369691 ◽

2015 ◽

Vol 35 (1) ◽

pp. 237-245 ◽

Cited By ~ 6

Author(s):

Liuzhong Yang ◽

Bing Zhou ◽

Xiaorui Li ◽

Zhihong Lu ◽

Weiwei Li ◽

...

Keyword(s):

Rna Interference ◽

Growth Inhibition ◽

Ubiquitin Ligase ◽

E3 Ubiquitin Ligase ◽

Physical Interaction ◽

Dependent Manner ◽

Ubiquitin Protein Ligase ◽

Proteasome Degradation ◽

Dose Dependent

Background/Aims: Although early studies show that Mdm2 is the primary E3 ubiquitin ligase for the p53 tumor suppressor, an increasing amount of data suggests that p53 ubiquitination and degradation are more complex than once thought. Here, we investigated the role of RNF125, a non-Mdm2 ubiquitin-protein ligase, in the regulation of p53. Methods and Results: RNF125 physically interacted with p53 in exogenous/endogenous co-immunoprecipitation (IP) and GST-pull down assay, and a C72/75A mutation of RNF125 did not interfere with this interaction. Expression of RNF125 decreased the level of p53 in a dose-dependent manner, whereas knockdown of RNF125 by RNA interference increased the level of p53. As shown by Western blotting and ubiquitin assay, RNF125 ubiquitinated p53 and targeted it for proteasome degradation. Furthermore, RNF125 repressed p53 functions including p53-dependent transactivation and growth inhibition. Conclusion: Our data suggest that RNF125 negatively regulates p53 function through physical interaction and ubiquitin-mediated proteasome degradation.

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Spontaneous and glucocorticoid-induced apoptosis in human mature T lymphocytes

Blood ◽

10.1182/blood.v86.11.4199.bloodjournal86114199 ◽

1995 ◽

Vol 86 (11) ◽

pp. 4199-4205 ◽

Cited By ~ 80

Author(s):

M Brunetti ◽

N Martelli ◽

A Colasante ◽

M Piantelli ◽

P Musiani ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Interleukin 2 ◽

Cell Number ◽

T Cell Subsets ◽

Dependent Manner ◽

Cell Repertoire ◽

Induced Apoptosis ◽

And Function ◽

Dose Dependent

Glucocorticoid (GC)-induced apoptosis is a well-recognized physiologic regulator of murine T-cell number and function. We have analyzed its mechanisms in human mature T cells, which have been thought to be insensitive until recently. Peripheral blood T cells showed sensitivity to GC-induced apoptosis soon after the proliferative response to a mitogenic stimulation, and were also sensitive to spontaneous (ie, growth factor deprivation-dependent) apoptosis. CD8+ T cells were more sensitive to both forms than CD4+ T cells. Acquisition of sensitivity to GC-induced apoptosis was not associated with any change in number or affinity of GC receptors. Both spontaneous and GC-induced apoptosis were increased by the macromolecular synthesis inhibitors, cycloheximide (CHX) and puromycin. A positive correlation between the degree of protein synthesis inhibition and the extent of apoptosis was observed. Interleukin-2 (IL-2) IL-4, and IL-10 protected (IL-2 > IL-10 > IL-4) T cells from both forms of apoptosis in a dose-dependent manner. Our data suggest that spontaneous and GC-induced apoptosis regulate the human mature T-cell repertoire by acting early after the immune response and differentially affecting T-cell subsets.

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Bisphenol A Modifies the Regulation Exerted by Testosterone on 5α-Reductase Isozymes in Ventral Prostate of Adult Rats

BioMed Research International ◽

10.1155/2013/629235 ◽

2013 ◽

Vol 2013 ◽

pp. 1-7 ◽

Cited By ~ 8

Author(s):

Pilar Sánchez ◽

Beatriz Castro ◽

Jesús M. Torres ◽

Asunción Olmo ◽

Raimundo G. del Moral ◽

...

Keyword(s):

Bisphenol A ◽

Prostate Gland ◽

Ventral Prostate ◽

Mrna Levels ◽

Dependent Manner ◽

Adult Rats ◽

Short Term Exposure ◽

Rat Prostate ◽

And Function ◽

Dose Dependent

The development, growth, and function of the prostate gland depend on androgen stimulation. The primary androgen in prostate is 5α-dihydrotestosterone (DHT) which is synthesized from circulating testosterone (T) through the action of 5α-reductase (5α-R). Although 5α-R occurs as five isozymes, only 5α-R1 and 5α-R2 are physiologically involved in steroidogenesis. The endocrine disruptor bisphenol A (BPA) alters sexual organs, including the prostate. Our previous findings indicated that BPA decreased the expression of 5α-R1 and 5α-R2 in rat prostate but also circulating T. Thus, it is unclear whether BPA exerts this effect on 5α-R isozymes by reducing circulating T or by any other mechanism. In this study, we examine the effects of short-term exposure to BPA at doses below 25 μg/Kg/d and above 300 μg/Kg/d of the TDI on mRNA levels of 5α-R1 and 5α-R2 in prostate of adult castrated rats supplemented with T to achieve constant circulating T levels. mRNA levels were measured by absolute quantitative RT-PCR, T levels by RIA, and DHT levels by ELISA. Our results indicated that in castrated rats treated with T BPA at the two doses studied significantly decreased the mRNA levels of both 5α-R isozymes in a dose-dependent manner without modifications in circulating T.

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Elevated carbon dioxide upregulates NBCn1 Na+/HCO3− cotransporter in human embryonic kidney cells

AJP Renal Physiology ◽

10.1152/ajprenal.00096.2013 ◽

2013 ◽

Vol 305 (12) ◽

pp. F1765-F1774 ◽

Cited By ~ 4

Author(s):

Alejandro Orlowski ◽

Lorena A. Vargas ◽

Ernesto A. Aiello ◽

Bernardo V. Álvarez

Keyword(s):

Cell Types ◽

Recovery Phase ◽

Kidney Cells ◽

Dependent Manner ◽

Human Embryonic Kidney ◽

Human Embryonic Kidney Cells ◽

Hek Cells ◽

And Function ◽

Acid Loading ◽

Dose Dependent

The NBCn1 Na+/HCO3− cotransporter catalyzes the electroneutral movement of 1 Na+:1 HCO3− into kidney cells. We characterized the intracellular pH (pHi) regulation in human embryonic kidney cells (HEK) subjected to NH4Cl prepulse acid loading, and we examined the NBCn1 expression and function in HEK cells subjected to 24-h elevated Pco2 (10–15%). After acid loading, in the presence of HCO3−, ∼50% of the pHi recovery phase was blocked by the Na+/H+ exchanger inhibitors EIPA (10–50 μM) and amiloride (1 mM) and was fully cancelled by 30 μM EIPA under nominally HCO3−-free conditions. In addition, in the presence of HCO3−, pHi recovery after acid loading was completely blocked when Na+ was omitted in the buffer. pHi recovery after acidification in HEK cells was repeated in the presence of the NBC inhibitor S0859, and the pHi recovery was inhibited by S0859 in a dose-dependent manner ( Ki = 30 μM, full inhibition at 60 μM), which confirmed NBC Na+/HCO3− cotransporter activation. NBCn1 expression increased threefold after 24-h exposure of cultured HEK cells to 10% CO2 and sevenfold after exposure to 15% CO2, examined by immunoblots. Finally, exposure of HEK cells to high CO2 significantly increased the HCO3−-dependent recovery of pHi after acid loading. We conclude that HEK cells expressed the NBCn1 Na+/HCO3− cotransporter as the only HCO3−-dependent mechanism responsible for cellular alkaline loading. NBCn1, which expresses in different kidney cell types, was upregulated by 24-h high-Pco2 exposure of HEK cells, and this upregulation was accompanied by increased NBCn1-mediated HCO3− transport.

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Sites of vulnerability on ricin B chain revealed through epitope mapping of toxin-neutralizing monoclonal antibodies

PLoS ONE ◽

10.1371/journal.pone.0236538 ◽

2020 ◽

Vol 15 (11) ◽

pp. e0236538

Author(s):

David J. Vance ◽

Amanda Y. Poon ◽

Nicholas J. Mantis

Keyword(s):

Monoclonal Antibodies ◽

Mammalian Cells ◽

Type I ◽

Dependent Manner ◽

Type Ii ◽

Single Chain ◽

Carbohydrate Recognition Domains ◽

And Function ◽

Golgi Network ◽

Dose Dependent

Ricin toxin’s B subunit (RTB) is a multifunctional galactose (Gal)-/N-acetylgalactosamine (GalNac)-specific lectin that promotes uptake and intracellular trafficking of ricin’s ribosome-inactivating subunit (RTA) into mammalian cells. Structurally, RTB consists of two globular domains (RTB-D1, RTB-D2), each divided into three homologous sub-domains (α, β, γ). The two carbohydrate recognition domains (CRDs) are situated on opposite sides of RTB (sub-domains 1α and 2γ) and function non-cooperatively. Previous studies have revealed two distinct classes of toxin-neutralizing, anti-RTB monoclonal antibodies (mAbs). Type I mAbs, exemplified by SylH3, inhibit (~90%) toxin attachment to cell surfaces, while type II mAbs, epitomized by 24B11, interfere with intracellular toxin transport between the plasma membrane and the trans-Golgi network (TGN). Localizing the epitopes recognized by these two classes of mAbs has proven difficult, in part because of RTB’s duplicative structure. To circumvent this problem, RTB-D1 and RTB-D2 were expressed as pIII fusion proteins on the surface of filamentous phage M13 and subsequently used as “bait” in mAb capture assays. We found that SylH3 captured RTB-D1 (but not RTB-D2) in a dose-dependent manner, while 24B11 captured RTB-D2 (but not RTB-D1) in a dose-dependent manner. We confirmed these domain assignments by competition studies with an additional 8 RTB-specific mAbs along with a dozen a single chain antibodies (VHHs). Collectively, these results demonstrate that type I and type II mAbs segregate on the basis of domain specificity and suggest that RTB’s two domains may contribute to distinct steps in the intoxication pathway.

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