scholarly journals WNT/β-CATENIN modulates the axial identity of ES derived human neural crest

2019 ◽  
Author(s):  
Gustavo A. Gomez ◽  
Maneeshi S. Prasad ◽  
Man Wong ◽  
Rebekah M. Charney ◽  
Patrick B. Shelar ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Neural Crest ◽  
Critical Role ◽  
Embryonic Stem ◽  
Dependent Manner ◽  
Robust Model ◽  
Magnitude Variation ◽  
First Time ◽  
Dose Dependent ◽  
Wnt Signal

ABSTRACTThe WNT/β-CATENIN pathway is critical for neural crest (NC) formation. However, the effects of the magnitude of the signal remains poorly defined. Here we evaluate the consequences of WNT magnitude variation in a robust model of human NC formation. This model is based on human embryonic stem cells induced by WNT signaling through the small molecule CHIR9902. In addition to its known effect on NC formation, we find that the WNT signal modulates the anterior-posterior axial identity of NCCs in a dose dependent manner, with low WNT leading to anterior OTX+, HOX-NC, and high WNT leading to posterior OTX−, HOX+ NC. Differentiation tests of posterior NC confirm expected derivatives including posterior specific adrenal derivatives, and display partial capacity to generate anterior ectomesenchymal derivatives. Furthermore, unlike anterior NC, posterior NC transit through a TBXT+/SOX2+ neuromesodermal precursor-like intermediate. Finally, we analyze the contributions of other signaling pathways in posterior NC formation, and suggest a critical role for FGF in survival/proliferation, and a requirement of BMP for NC maturation. As expected RA and FGF are able to modulate HOX expression in the posterior NC, but surprisingly, RA supplementation prohibits anterior, but only reduces, posterior NC formation. This work reveals for the first time that the amplitude of WNT signaling can modulate the axial identity of NC cells in humans.

The P-element-induced silencing effect of KP transposons is dose dependent in Drosophila melanogaster

Genome ◽  
2011 ◽  
Vol 54 (9) ◽  
pp. 752-762 ◽  
Author(s):  
Alireza Sameny ◽  
John Locke
Keyword(s):  
Drosophila Melanogaster ◽  
Critical Role ◽  
Mutagenic Effect ◽  
P Element ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
P Elements ◽  
Single Well ◽  
Dose Dependent

Transposable elements are found in the genomes of all eukaryotes and play a critical role in altering gene expression and genome organization. In Drosophila melanogaster, transposable P elements are responsible for the phenomenon of hybrid dysgenesis. KP elements, a deletion-derivative of the complete P element, can suppress this mutagenic effect. KP elements can also silence the expression of certain other P-element-mediated transgenes in a process called P-element-dependent silencing (PDS), which is thought to involve the recruitment of heterochromatin proteins. To explore the mechanism of this silencing, we have mobilized KP elements to create a series of strains that contain single, well-defined KP insertions that show PDS. To understand the quantitative role of KP elements in PDS, these single inserts were combined in a series of crosses to obtain genotypes with zero, one, or two KP elements, from which we could examine the effect of KP gene dose. The extent of PDS in these genotypes was shown to be dose dependent in a logarithmic rather than linear fashion. A logarithmic dose dependency is consistent with the KP products interacting with heterochromatic proteins in a concentration-dependent manner such that two molecules are needed to induce gene silencing.

Mode of Action of the Hypertrehalosaemic Peptides from the American Cockroach

1985 ◽  
Vol 40 (9-10) ◽  
pp. 670-676 ◽  
Author(s):  
Gerd Gäde
Keyword(s):  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Mode Of Action ◽  
Glycogen Phosphorylase ◽  
Fat Body ◽  
American Cockroach ◽  
Dependent Manner ◽  
Low Concentrations ◽  
First Time ◽  
Dose Dependent

Abstract Although crude extracts of cockroach (Periplaneta amencana) corpora cardiaca have been shown previously to affect the activity of adenylate cyclase and phosphorylase, we demonstrate in the present study for the first time that low concentrations (0.5 to 5 pmol) of the synthetic myoactive peptides. M I and M II, also affect these systems; these myoactive peptides are identical to the hypertrehalosaemic hormones I and II, and cause an increase in the concentration of the second messenger cyclic AMP in the fat body.In addition, both octapeptides activate fat body glycogen phosphorylase and promote breakdown of fat body glycogen. Both peptides increase the levels to haemolymph carbohydrate in a dose-dependent manner.

scholarly journals The Influence of Bee Venom Melittin on the Functioning of the Immune System and the Contractile Activity of the Insect Heart—A Preliminary Study

Toxins ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 494 ◽  
Author(s):  
Jan Lubawy ◽  
Arkadiusz Urbański ◽  
Lucyna Mrówczyńska ◽  
Eliza Matuszewska ◽  
Agata Światły-Błaszkiewicz ◽  
...  
Keyword(s):  
Immune System ◽  
Contractile Activity ◽  
Model Organism ◽  
Dependent Manner ◽  
Physiological Studies ◽  
Almost All ◽  
First Time ◽  
Dose Dependent ◽  
Positive Effect

Melittin (MEL) is a basic polypeptide originally purified from honeybee venom. MEL exhibits a broad spectrum of biological activity. However, almost all studies on MEL activity have been carried out on vertebrate models or cell lines. Recently, due to cheap breeding and the possibility of extrapolating the results of the research to vertebrates, insects have been used for various bioassays and comparative physiological studies. For these reasons, it is valuable to examine the influence of melittin on insect physiology. Here, for the first time, we report the immunotropic and cardiotropic effects of melittin on the beetle Tenebrio molitor as a model insect. After melittin injection at 10−7 M and 10−3 M, the number of apoptotic cells in the haemolymph increased in a dose-dependent manner. The pro-apoptotic action of MEL was likely compensated by increasing the total number of haemocytes. However, the injection of MEL did not cause any changes in the percent of phagocytic haemocytes or in the phenoloxidase activity. In an in vitro bioassay with a semi-isolated Tenebrio heart, MEL induced a slight chronotropic-positive effect only at a higher concentration (10−4 M). Preliminary results indicated that melittin exerts pleiotropic effects on the functioning of the immune system and the endogenous contractile activity of the heart. Some of the induced responses in T. molitor resemble the reactions observed in vertebrate models. Therefore, the T. molitor beetle may be a convenient invertebrate model organism for comparative physiological studies and for the identification of new properties and mechanisms of action of melittin and related compounds.

scholarly journals Cyclic AMP-dependent Protein Lysine Acylation in Mycobacteria Regulates Fatty Acid and Propionate Metabolism

2013 ◽  
Vol 288 (20) ◽  
pp. 14114-14124 ◽  
Author(s):  
Subhalaxmi Nambi ◽  
Kallol Gupta ◽  
Moitrayee Bhattacharyya ◽  
Parvathy Ramakrishnan ◽  
Vaishnavi Ravikumar ◽  
...  
Keyword(s):  
Critical Role ◽  
Fatty Acyl ◽  
Intracellular Camp ◽  
Dependent Manner ◽  
Multiple Substrates ◽  
Propionate Metabolism ◽  
Lysine Residues ◽  
Dependent Protein ◽  
First Time ◽  
Camp Levels

Acetylation of lysine residues is a posttranslational modification that is used by both eukaryotes and prokaryotes to regulate a variety of biological processes. Here we identify multiple substrates for the cAMP-dependent protein lysine acetyltransferase from Mycobacterium tuberculosis (KATmt). We demonstrate that a catalytically important lysine residue in a number of FadD (fatty acyl CoA synthetase) enzymes is acetylated by KATmt in a cAMP-dependent manner and that acetylation inhibits the activity of FadD enzymes. A sirtuin-like enzyme can deacetylate multiple FadDs, thus completing the regulatory cycle. Using a strain deleted for the KATmt ortholog in Mycobacterium bovis Bacillus Calmette-Guérin (BCG), we show for the first time that acetylation is dependent on intracellular cAMP levels. KATmt can utilize propionyl CoA as a substrate and, therefore, plays a critical role in alleviating propionyl CoA toxicity in mycobacteria by inactivating acyl CoA synthetase (ACS). The precision by which mycobacteria can regulate the metabolism of fatty acids in a cAMP-dependent manner appears to be unparalleled in other biological organisms and is ideally suited to adapt to the complex environment that pathogenic mycobacteria experience in the host.

scholarly journals A Mechano-Activated Cell Reporter System as a Proxy for Flow-Dependent Endothelial Atheroprotection

2018 ◽  
Vol 23 (8) ◽  
pp. 869-876
Author(s):  
Bendix R. Slegtenhorst ◽  
Oscar R. Fajardo Ramirez ◽  
Yuzhi Zhang ◽  
Zahra Dhanerawala ◽  
Stefan G. Tullius ◽  
...  
Keyword(s):  
Vascular Endothelium ◽  
Critical Role ◽  
Green Fluorescence Protein ◽  
Dependent Manner ◽  
Reporter System ◽  
Health And Disease ◽  
Fluorescence Protein ◽  
Biomechanical Stimuli ◽  
Dose Dependent

The vascular endothelium plays a critical role in the health and disease of the cardiovascular system. Importantly, biomechanical stimuli generated by blood flow and sensed by the endothelium constitute important local inputs that are translated into transcriptional programs and functional endothelial phenotypes. Pulsatile, laminar flow, characteristic of regions in the vasculature that are resistant to atherosclerosis, evokes an atheroprotective endothelial phenotype. This atheroprotective phenotype is integrated by the transcription factor Kruppel-like factor-2 (KLF2), and therefore the expression of KLF2 can be used as a proxy for endothelial atheroprotection. Here, we report the generation and characterization of a cellular KLF2 reporter system, based on green fluorescence protein (GFP) expression driven by the human KLF2 promoter. This reporter is induced selectively by an atheroprotective shear stress waveform in human endothelial cells, is regulated by endogenous signaling events, and is activated by the pharmacological inducer of KLF2, simvastatin, in a dose-dependent manner. This reporter system can now be used to probe KLF2 signaling and for the discovery of a novel chemical-biological space capable of acting as the “pharmacomimetics of atheroprotective flow” on the vascular endothelium.

scholarly journals miR-103 Regulates Oxidative Stress by Targeting the BCL2/Adenovirus E1B 19 kDa Interacting Protein 3 in HUVECs

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Mao-Chun Xu ◽  
Xiu-Fang Gao ◽  
Changwu Ruan ◽  
Zhi-Ru Ge ◽  
Ji-De Lu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Critical Role ◽  
Cell Activity ◽  
Antioxidant Effect ◽  
Dependent Manner ◽  
Ros Production ◽  
Interacting Protein ◽  
Adenovirus E1b ◽  
Antioxidative Therapy ◽  
First Time

Oxidative stress plays a critical role in cardiovascular diseases. Salidroside, a glycoside fromRhodiola rosea, has been used as an antioxidative therapy for oxidative injury in cardiac diseases. However, the mechanism underlying its antioxidant effect needs to be elucidated. Treatment of HUVECs with H2O2significantly decreased the expression of miR-103 in a dose- and time-dependent manner, whereas pretreatment with salidroside significantly inhibited this decrease. Subsequent analysis showed that overexpression of miR-103 abrogated cell activity and ROS production induced by H2O2. Bcl2/adenovirus E1B 19 kDa interacting protein 3 (BNIP3) was determined to be a novel miR-103 target in HUVECs. Interestingly, H2O2treatment upregulated BNIP3 expression; in turn, this effect was inhibited by pretreatment with salidroside. Further studies confirmed that the knockdown of BNIP3 enhanced cell activity and suppressed the ROS production induced by H2O2. These results demonstrated for the first time that salidroside protects HUVECs in part by upregulating the expression of miR-103, which mediates BNIP3 downregulation and plays an important role in the cytoprotective actions.

Characterization of the role of CaMKI-like kinase (CKLiK) in human granulocyte function

Blood ◽  
2005 ◽  
Vol 106 (3) ◽  
pp. 1076-1083 ◽  
Author(s):  
Sandra Verploegen ◽  
Laurien Ulfman ◽  
Hanneke W. M. van Deutekom ◽  
Corneli van Aalst ◽  
Henk Honing ◽  
...  
Keyword(s):  
Respiratory Burst ◽  
Critical Role ◽  
Neutrophil Migration ◽  
Platelet Activating Factor ◽  
Dependent Manner ◽  
Functional Responses ◽  
Effector Functions ◽  
C Terminus ◽  
Human Granulocytes ◽  
Dose Dependent

AbstractActivation of granulocyte effector functions, such as induction of the respiratory burst and migration, are regulated by a variety of relatively ill-defined signaling pathways. Recently, we identified a novel Ca2+/calmodulin-dependent kinase I-like kinase, CKLiK, which exhibits restricted mRNA expression to human granulocytes. Using a novel antibody generated against the C-terminus of CKLiK, CKLiK was detected in CD34+-derived neutrophils and eosinophils, as well as in mature peripheral blood granulocytes. Activation of human granulocytes by N-formyl-methionyl-leucyl-phenylalanine (fMLP) and platelet-activating factor (PAF), but not the phorbol ester PMA (phorbol 12-myristate-13-acetate), resulted in induction of CKLiK activity, in parallel with a rise of intracellular Ca2+ [Ca2+]i. To study the functionality of CKLiK in human granulocytes, a cell-permeable CKLiK peptide inhibitor (CKLiK297-321) was generated which was able to inhibit kinase activity in a dose-dependent manner. The effect of this peptide was studied on specific granulocyte effector functions such as phagocytosis, respiratory burst, migration, and adhesion. Phagocytosis of Aspergillus fumigatus particles was reduced in the presence of CKLiK297-321 and fMLP-induced reactive oxygen species (ROS) production was potently inhibited by CKLiK297-321 in a dose-dependent manner. Furthermore, fMLP-induced neutrophil migration on albumin-coated surfaces was perturbed, as well as β2-integrin-mediated adhesion. These findings suggest a critical role for CKLiK in modulating chemoattractant-induced functional responses in human granulocytes.

scholarly journals Sip1 mediates an E-cadherin-to-N-cadherin switch during cranial neural crest EMT

2013 ◽  
Vol 203 (5) ◽  
pp. 835-847 ◽  
Author(s):  
Crystal D. Rogers ◽  
Ankur Saxena ◽  
Marianne E. Bronner
Keyword(s):  
Neural Crest ◽  
Neural Tube ◽  
Molecular Mechanisms ◽  
Epithelial To Mesenchymal Transition ◽  
Critical Role ◽  
Embryonic Stem ◽  
Neural Crest Cell ◽  
Stem Cell Population ◽  
Mesenchymal Transition ◽  
E Cadherin

The neural crest, an embryonic stem cell population, initially resides within the dorsal neural tube but subsequently undergoes an epithelial-to-mesenchymal transition (EMT) to commence migration. Although neural crest and cancer EMTs are morphologically similar, little is known regarding conservation of their underlying molecular mechanisms. We report that Sip1, which is involved in cancer EMT, plays a critical role in promoting the neural crest cell transition to a mesenchymal state. Sip1 transcripts are expressed in premigratory/migrating crest cells. After Sip1 loss, the neural crest specifier gene FoxD3 was abnormally retained in the dorsal neuroepithelium, whereas Sox10, which is normally required for emigration, was diminished. Subsequently, clumps of adherent neural crest cells remained adjacent to the neural tube and aberrantly expressed E-cadherin while lacking N-cadherin. These findings demonstrate two distinct phases of neural crest EMT, detachment and mesenchymalization, with the latter involving a novel requirement for Sip1 in regulation of cadherin expression during completion of neural crest EMT.

scholarly journals Gi proteins mediate activation of the canonical hedgehog pathway in the myocardium

2014 ◽  
Vol 307 (1) ◽  
pp. H66-H72 ◽  
Author(s):  
Christian J. Carbe ◽  
Lan Cheng ◽  
Sankar Addya ◽  
Jessica I. Gold ◽  
Erhe Gao ◽  
...  
Keyword(s):  
Purinergic Signaling ◽  
Transmembrane Protein ◽  
Critical Role ◽  
Transcriptional Response ◽  
Neonatal Rat ◽  
Small Subset ◽  
Dependent Manner ◽  
Gli1 Expression ◽  
Ventricular Cardiomyocytes ◽  
First Time

During myocardial ischemia, upregulation of the hedgehog (Hh) pathway promotes neovascularization and increases cardiomyocyte survival. The canonical Hh pathway activates a transcriptional program through the Gli family of transcription factors by derepression of the seven-transmembrane protein smoothened (Smo). The mechanisms linking Smo to Gli are complex and, in some cell types, involve coupling of Smo to Gi proteins. In the present study, we investigated, for the first time, the transcriptional response of cardiomyocytes to sonic hedgehog (Shh) and the role of Gi protein utilization. Our results show that Shh strongly activates Gli1 expression by quantitative PCR in a Smo-dependent manner in neonatal rat ventricular cardiomyocytes. Microarray analysis of gene expression changes elicited by Shh and sensitive to a Smo inhibitor identified a small subset of 37 cardiomyocyte-specific genes regulated by Shh, including some in the PKA and purinergic signaling pathways. In addition, neonatal rat ventricular cardiomyocytes infected with an adenovirus encoding GiCT, a peptide that impairs receptor-Gi protein coupling, showed reduced activation of Hh targets. In vitro data were confirmed in transgenic mice with cardiomyocyte-inducible GiCT expression. Transgenic GiCT mice showed specific reduction of Gli1 expression in the heart under basal conditions and failed to upregulate the Hh pathway upon ischemia and reperfusion injury, unlike their littermate controls. This study characterizes, for the first time, the transcriptional response of cardiomyocytes to Shh and establishes a critical role for Smo coupling to Gi in Hh signaling in the normal and ischemic myocardium.

scholarly journals Torque Teno Virus (SANBAN Isolate) ORF2 Protein Suppresses NF-κB Pathways via Interaction with IκB Kinases

2007 ◽  
Vol 81 (21) ◽  
pp. 11917-11924 ◽  
Author(s):  
Hong Zheng ◽  
Linbai Ye ◽  
Xiaonan Fang ◽  
Baozong Li ◽  
Yuhua Wang ◽  
...  
Keyword(s):  
Western Blot ◽  
Nuclear Factor Κb ◽  
Torque Teno Virus ◽  
Dependent Manner ◽  
Nuclear Factor ◽  
Innate And Adaptive Immunity ◽  
Reading Frame ◽  
Orf2 Protein ◽  
First Time ◽  
Dose Dependent

ABSTRACT Since the first discovery of Torque teno virus (TTV) in 1997, many researchers focused on its epidemiology and transcriptional regulation, but the function of TTV-encoded proteins remained unknown. The function of the TTV open reading frame (ORF) in the nuclear factor κB (NF-κB) pathway has not yet been established. In this study, we found for the first time that the TTV ORF2 protein could suppress NF-κB activity in a dose-dependent manner in the canonical NF-κB pathway. By Western blot analysis, we proved that the TTV ORF2 protein did not alter the level of NF-κB expression but prevented the p50 and p65 subunits from entering the nucleus due to the inhibition of IκBα protein degradation. Further immunoprecipitation assays showed that the TTV ORF2 protein could physically interact with IKKβ as well as IKKα, but not IKKγ. Luciferase assays and Western blot experiments showed that the TTV ORF2 protein could also suppress NF-κB activity in the noncanonical NF-κB pathway and block the activation and translocation of p52. Finally, we found that the TTV ORF2 protein inhibited the transcription of NF-κB-mediated downstream genes (interleukin 6 [IL-6], IL-8, and COX-2) through down-regulation of NF-κB. Together, these data indicate that the TTV ORF2 protein suppresses the canonical and noncanonical NF-κB pathways, suggesting that the TTV ORF2 protein may be involved in regulating the innate and adaptive immunity of organisms, contributing to TTV pathogenesis, and even be related to some diseases.

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