bluuebunny/crossref_metadata_2025_split huggingface dataset:
Endothelin‐1 Inhibits Nox1 in Human Abdominal Aortic Endothelial cells: a Novel Function of ETB1 receptors
Authors: Dammanahalli Karigowda , Sun Zhongjie 
Published: June 2021

Hypothesis.Endothelin‐1 (ET‐1) inhibits Nox1 activity and decreases superoxide production and cell proliferation in human abdominal aortic endothelial cells (HAAECs).Methods and Results.HAAECs were exposed ET‐1 (10–30 nM) at different time intervals and superoxide production was measured by flow cytometry. Intracellular reactive oxygen species (ROS) was examined by confocal microscopy using 2′,7′‐dichlorodihydrofluorescein diacetate. NADPH oxidase activity was determined using lucigenin enhanced chemiluminescence in the presence and absence of siRNA for ETB1 receptors or Nox1. ET1 significantly attenuated Nox1 activity, ROS generation, and cell proliferation which could be abolished by silence of Nox1 gene. Furthermore, RNAi silence of ETB1 receptors significantly increased Nox1 activity and blocked the inhibitory effect of ET1 on Nox1 activity. ET1 enhanced bioavailability of intracellular NO measured using DAF‐2. ET1 did not affect Nox1 protein expression. Nox2 was not dectable in HAAECs. Activation of ETB1 receptors by ET1 suppressed protein phosphorylation of pyk2 (Y402) and Rac1, suggesting that ET1 inhibits Nox1 activity via ETB1‐Pyk2‐Rac1 pathway.Conclusions.This study demonstrated, for the first time, that that ET1 inhibited Nox1 activity, ROS production, and ell proliferation in HAAECs via ETB1‐Pyk2‐Rac1 pathway.
How to make a limb: developmental paradigms
Authors: Niswander Lee Ann 
Published: June 2021

The embryonic vertebrate limb is a classic paradigm for the study of pattern formation, cell growth and death, and skeletal formation. Our understanding of the molecular signals that regulate limb patterning is relatively complete. However, many questions remain as to how these signals are interpreted and translated into skeletal elements that are adapted to the needs of each animal on land, sea and air. Outstanding questions in patterning and skeletal formation include how and when are limb cells specified and acquire distinct cell fates in order to contribute to specific skeletal elements and what are the cellular and molecular mechanisms that lead to the establishment of the skeletal elements of the correct size and shape?Our work is driven forward by two approaches. The first is the creation of mouse mutants with defects in limb development. We then clone the responsible gene that is mutated and discover its mechanism of action. The second approach uses a new imaging method to watch in real time as the limb mesenchyme undergoes the early steps of cartilage formation. We then combine this with the study of limb mesenchyme from mouse mutants to begin to understand the cell behaviors that are affected in mutants with too many digits, too few digits, or defects in cartilage formation. Furthermore, we have used our knowledge of limb development in models organisms, the mouse and chick, to begin to unravel the molecular mechanisms that underlie evolutionary change in the bat.
Signaling pathways regulating the airway phenotype of mice exhibiting airway surface dehydration
Authors: Livraghi Alessandra , Grubb Barbara R. , O’Neal Wanda K. , Mall Marcus A. , Boucher Richard C. , Randell Scott H. 
Published: June 2021

Overexpression of the epithelial Na+ channel βsubunit (gene Scnn1b) in mouse airways results in airway surface dehydration, neonatal mortality, mucous cell metaplasia and airway inflammation. Crossbreeding Scnn1b‐Tg mice with gene‐deficient mice enables quick and efficient determination of specific pathways relevant to the development of lung pathology. We bred Scnn1b‐Tg mice with mice deficient in: 1) IL‐4 receptor alpha chain (IL‐4Rα), shared by IL‐4 and IL‐13 receptors; 2) TNFα; 3) TNFα receptor 1 (TNFαR1), and evaluated inflammatory infiltrate, cytokine profile, lung pathology, and airway bioelectrics. In Scnn1b‐Tg mice, absence of IL‐4Rα improved neonatal survival and was associated with decreased mucous cells and eosinophilic infiltrate at day 10. However, absence of IL‐4Rα did not affect the chronic inflammatory infiltrate and lung pathology in adult Scnn1b‐Tg mice. Although TNFα was increased in Scnn1b airways, absence of TNFα or TNFαR1 did not ameliorate the lung phenotype of Scnn1b‐Tg mice nor modify airways bioelectrics. To assess the contribution of IL‐1β and TLR pathways, we are currently breeding the Scnn1b‐Tg mice with mice deficient in the adaptor molecule MyD88. These results indicate that multiple pathways contribute to airway inflammation and remodeling in the setting of surface dehydration and mucus stasis.Funded by CFF grants LIVRAG04I0 and RANDEL07P0, and NIH P50 HL060280 to R.C.B
Nuclear mRNA export requires coordinated FG‐Nup binding and DEAD‐box protein‐mediated remodeling events
Authors: Wente Susan R. , Terry Laura J. , Alcazar‐Roman Abel R. , Tran Elizabeth J. 
Published: June 2021

Nucleocytoplasmic transport of proteins and nucleic acids is essential for proper gene expression. Using the Saccharomyces cerevisiae model, we discovered key events for directional export of messenger (m) RNA. Distinct steps were pinpointed at nuclear, central and cytoplasmic nuclear pore complex (NPC) structures. Nearly half of the ∼30 NPC proteins harbor Phe‐Gly (FG) repeat domains that potentially serve as binding sites for the shuttling mRNA export receptor Mex67. A large‐scale deletion strategy was employed to generate mutants lacking discrete combinations of FG‐domains, and specific subsets of FG domains were required for mRNA export. The FG mutants also revealed multiple functionally independent translocation routes through NPCs. mRNA export required FG domains on the nuclear NPC face (presumably for initial docking at the NPC) and in the NPC central core. At the cytoplasmic NPC face, we found that the RNA‐dependent ATPase activity of the DEAD‐box protein Dbp5 was stimulated by inositol hexakisphosphate‐bound Gle1. The ADP‐bound form of Dbp5 triggered release of the RNA‐binding protein Nab2 from RNA. This novel nucleotide‐dependent switch mechanism remodeled mRNA‐protein complexes for directional translocation. We predict that these FG‐binding and mRNP remodeling steps are coupled for spatial regulation of mRNA export through and subsequent release from the NPC.Supported by grants from the NIGMS.
Effect of dietary protein level on whole body protein turnover in the adult cat (Felis catus)
Authors: Wester Timothy J , Weidgraaf Karin , Ugarte Claudia E 
Published: June 2021

The domestic cat is an obligate carnivore and as such has a high protein requirement. However, little is known about how protein turnover is affected by dietary protein intake in the cat. In the current study, kinetics of [1‐13C]Leu metabolism were used to quantify rates of whole body protein synthesis, degradation, and oxidation in adult cats (n = 6) fed diets containing 15, 40, or 65% of the ME intake as CP. Cats were fed the test diets to maintain BW for a minimum of 3 wk before the day of [1‐13C]Leu infusion. They were fed hourly on day of infusion. Values for Leu flux, non‐oxidative Leu disposal (NOLD, an indication of protein synthesis), Leu rate of appearance into the plasma (Ra, an indication of protein degradation), and Leu oxidation on different diets were as follows:As indicated by rate of whole body Leu flux, cats fed a diet that supplied 65% of ME intake as CP had elevated rates of whole body protein turnover via chiefly increased rates of amino acid oxidation. This study showed that during a period of marginal protein intake, cats modulated protein turnover to conserve body protein. Research supported by the Massey University Research Fund.
Oral‐iron‐associated depletion of the fecal antioxidant capacity state is improved by concurrent dietary antioxidants
Authors: Orozco Monica N , Friel James K , Schuemann Klaus , Solomons Noel W 
Published: June 2021

Background:Iron's oxidative nature and ease to participate in redox reactions confer it the ability to produce reactive oxygen species (ROS) that may alter the normal antioxidant capacity state of feces, leading to oxidative damage in the colon.Objectives:To evaluate dietary antioxidants’ effect on the fecal antioxidant capacity state depleted by oral Fe supplementation.Methods:12 adult males received 3 7‐d treatments of: A=120 mg Fe (FeSO4), B=120 mg Fe + 30 mg carotenoids (CT) + 36.8 mg tocopherols and tocotrienols (TT), and C=120 mg Fe + 60 mg CT + 73.6 mg TT. Stool samples from baseline, active supplementation and washout phases were assayed for their capacity to blunt the production of indicator hydroxylated salicylic acid derivatives resulting from in vitro free‐radical attack by Fe3+ exposure.Results:A significant reduction on the production of hydroxylated compounds with respect to regimen A was seen for treatments B and C. Baseline antioxidant capacity state was virtually restored with dietary CT + TT antioxidants.Conclusions:Dietary antioxidants may improve the depleted fecal antioxidant capacity state of persons taking Fe supplementation.Sponsored in part by the Malaysian Palm Oil Board and INF‐EMF.
Manipulation of lipid bioaccessibility of almonds influences postprandial lipemia in healthy human subjects
Authors: Berry Sarah Elizabeth Emma , Ellis Peter , Tydeman Elizabeth , Lewis Hannah , Picout David , Phalora Ravneet , Rosborough Jennfier 
Published: June 2021

An exaggerated postprandial lipemic response is associated with increased risk of coronary heart disease, due to acute effects on lipids, oxidative stress, hemostatic factors and vascular function. Lipid released slowly from a complex food matrix during digestion may attenuate postprandial lipemia1. The present study therefore investigates the effects of lipid release (lipid bioaccessibility (LB)) on postprandial changes (over 8h) in plasma triacylglycerol (TAG) concentration, oxidative stress (measured by 8‐isoprostane F2α) and vascular function (measured by peripheral augmentation index (PAIx)). Subjects (n = 20, aged 18–40y) were fed test meals containing 50g fat of low LB (intact whole almonds; WA), high LB (almond oil + defatted almond flour; AO) or as a control meal (CO) in a randomised cross‐over design, with 1‐wk washout. The postprandial increase in plasma TAG was significantly lower (74% & 58% lower incremental area under curve) following the WA vs. the AO and CO meals, respectively (P<0.001). The peak reduction in PAIx (by −9.5%, −10.1% & −12.6% at 2h following WA, AO and CO meals respectively, time effect; P<0.001) was not significantly different between meals. There were no changes in plasma 8‐isoprostane F2α concentrations. Reducing LB of almonds beneficially influences postprandial lipemia.This study was funded by the Almond Board of California
Mammalian Scribble regulates the assembly of epithelial tight junctions
Authors: Young Cheryl , Ivanov Andrei , Nusrat Asma 
Published: June 2021

Scribble, Disc‐large (DLG), and Lethal giant larvae (LGL) tumor suppressor proteins have been implicated in the regulation of epithelial cell polarity. However, the mechanisms by which these proteins contribute to epithelial polarity are not well understood. Since tight junctions (TJs) play an important role in regulating intestinal epithelial cell (IEC) polarity and barrier function, we examined if these proteins participate in TJ dynamics and in the establishment of the IEC barrier function. Model IECs, SK‐CO15 and T84 cells were used for these studies, and TJ assembly/disassembly was analyzed using the calcium switch assay. Fluorescence labeling/confocal microscopy demonstrated that Scribble and LGL1 but not DLG1 co‐localized with TJ proteins, occludin and zonula occludens‐1. Additionally, Scribble and LGL1 co‐internalized with the TJ proteins during TJ disassembly induced by calcium depletion. Furthermore, siRNA‐mediated downregulation of Scribble, but not LGL1 or DLG1 significantly attenuated the functional and morphologic assembly of TJs during calcium repletion. Downregulation of Scribble did not influence expression of DLG1 or LGL1 and vise versa, and these proteins did not co‐associate as determined by immunoprecipitation. In conclusion, we demonstrate a unique role of mammalian Scribble in regulation of IEC TJ assembly and in the development of epithelial barrier function.Supported by CCFA Career Development Award (AII), NIH DK‐59888 (AN), and NIH DK‐55567 (AN)
Electronegative LDL disrupts mitochondrial homeostasis: a novel mechanism for cigarette smoking‐associated endothelial dysfunction
Authors: Tang Daming , Burns Alan R , Lu Jonathan , Chen Hsin‐Hung , Wu Huanzhu , Engler David A , Sawamura Tatsuya , Yang Chao‐Yuh , Chen Chu‐Huang 
Published: June 2021

Background and objectives: We reported that cigarette smoking provokes formation of L5, an electronegative low‐density lipoprotein (LDL), which inhibits maturation of endothelial progenitor cells. Here we investigated whether L5 disrupts mitochondrial homeostasis essential for EC survival.Methods and results: Using ion‐exchange chromatography, L5, an electronegative LDL, was detected in smoker's plasma but nonsmokers. L5 dose‐dependently decreased mitochondrial membrane potential in cultured human umbilical venous ECs which was fluorescently exhibited by leakage of JC‐1 into the cytoplasm and flow cytometry assay. Trans‐electron microscopy revealed crista disappearance and membrane disintegration of the mitochondria, accompanied by chromatin fragmentation in the nucleus. These changes were associated with activation of caspase‐3 and mitochondrial release of cytochrome c and Smac. L5 markedly reduced expression of antiapoptotic proteins Bcl‐2 and c‐IAP. Addition of L1 in physiological ratios to the culture media did not compromise L5's bioactivity. Blockade of LOX‐1 with its neutralizing antibody or silencing it with siRNAs protected mitochondrial integrity and prevented apoptosis induced by L5.Conclusions: cigarette smoking is associated with the formation of L5, which promotes HUVEC apoptosis by impairing mitochondrial integrity via the LOX‐1 receptor.
Arterial branching morphogenesis
Authors: Simons Michael 
Published: June 2021

Branching is the key event in formation of vascular trees. Branching morphogenesis occurs not only during embryonic developments but also in adult tissues in response to a variety of signals such as organ growth, ischemia and tissue injury. Despite its obvious importance, little is known about signals inducing arterial branching, the intracellular signaling cascades responsible for it, or the cell types involved. While studying disruption of synectin gene expression, we noted, both in mice and in zebrafish models, significant abnormalities in arteriogenesis, including a reduction in the arterial tree size and a profound decrease in the number of arterial branches. Remarkably, neither venous nor lymphatic systems seem affected. Thus, it appears that synectin plays a key role in regulation of arterial differentiation as well branching.Molecular defects in synectin−/− endothelial cells include decreased responses to VEGF, FGF2 and PDGF stimulation, abnormal activation and mis‐localization of activated Rac1 and decreased Erk‐1/2 activation. The latter appears to be particularly important in regulation of arterial morphogenesis.
A Temporal Code to generate Specificity in Inflammatory Signaling
Authors: Hoffmann Alexander 
Published: June 2021

The immune system responds specifically and appropriately to diverse pathogens. Strikingly, distinct gene expression programs all require the same transcription factor: NF‐kappaB.Interestingly, different stimuli lead to different dynamic profiles of NF‐kappaB activity. In order to investigate the role of dynamic regulation further, we constructed a mathematical model that recapitulates the control of NF‐kappaB activation by the regulated synthesis and degradation of the three canonical IkappaB proteins.Guided by computational simulations, we engineered a mutant cell line that is defective in NF‐kappaB temporally controlled amplitude modulation (AM); these cells are still responsive to inflammatory stimuli but, remarkably, lose stimulus‐specificity in gene expression. We therefore postulate the existence of a temporal code to generate stimulus‐specific inflammatory gene expression programs.I will present computational tools to probe this stimulus‐specific temporal code. By perturbing the parameter space pharmacologically, we provide experimental support for computational predictions. Our studies suggest that the temporal code of inflammatory signaling can be harnessed to maximize the specific efficacy of pharmacological agents.
The epicardium has potential in cardiac healing and regeneration in mammals
Authors: Martin Jody Carl 
Published: June 2021

The proepicardium is a small transient structure that develops at the base of the heart, adjacent to the septum transversum. It is made up of pluripotent cells that migrate to the developing heart to give rise to fibroblasts, vascular support cells, cardiomyocytes, and the epicardium. It is unclear if and when proepicardial cells lose their pluripotential.After an ischemic event, such as a heart attack, the heart compensates for cardiomyocyte loss with fibrosis to maintain the integrity of the cardiac wall, preventing rupture. The result is a stiffer and less effective pump.These experiments show the ability of embryonic epicardial cells to contribute to myocardial healing In Vitro after transmural laceration. Following injury, the whole embryonic heart is explanted and cultured. Further studies in adult mice show that epicardial cells are present at the site of injury in a surgical model of cardiac damage. Further studies will show the fate of cells arising from the epicardium that contribute to the healing response following cardiac injury.These preliminary results suggest that epicardial cells are able to migrate and differentiate in response to injury. The epicardium may be a source of pluripotent cells that, with the right encouragement, may have the ability to contribute new vasculature as well as new myocytes after an ischemic event.
Self orientation of cell and cell‐secreted collagen in a tissue‐engineered cornea grown on microstructured polystyrene
Authors: Auger François A. , Veres Teodor , Cui Bo , Deschambeault Alexandre , Carrier Patrick , Germain Lucie , Guillemette Maxime D. 
Published: June 2021

The corneal stroma is composed of many layers of fibroblasts and collagen that are oriented longitudinally within a layer and the layers display a shift of approximately 60‐degree angle between each other. This type of structure is known to be responsible for the transparency of the cornea. Using the self‐assembly approach to cultured cell sheets, we evaluated how cell‐secreted collagen reaction could be influenced by external physical cues. Microstructured polystyrene samples used for cell culture were prepared by hot embossing, replicated and transferred from a Si master of different grating periods and linewidths to a polystyrene substrate. We observed that cell division occurred only in the longitudinal axis of the gratings instead of the random cell orientation seen in the control. Cells forming the first layer on the substrate aligned themselves in the same longitudinal direction as the gratings. We also observed that after 7 days in culture the cells of the second layer, forming on top of the first one, aligned themselves at an angle of approximately 60 degree from the first one, and so did the cell‐secreted collagen fibres. These results are very promising for the reconstruction of autologous tissue‐engineered cornea since optimization of transparency is of paramount importance for the patients who will benefit from this type of surgery.Financial support is provided by the National Research Council‐Canadian Institutes of Health Research (grant 66473).
Expression of alpha‐synuclein (AS) in autonomic neurons is increased in Parkinson's disease (PD)
Authors: Munoz David G , Gold Andrea 
Published: June 2021

Background and objectiveWe have previously shown that expression of the main protein constituent of Lewy bodies, AS, is detectable in autonomic neurons in a subset of the adult population. The objective was to determine wheteher expression has greater prevalence or intensity in PD than in the general population or patients with Alzheimer's disease (AD)MethodsArchival autopsy samples of colon obtained from adult patients with pathologically confirmed PD, AD, or no neurological disease were immunostained with anti AS antibody KM51 diluted 1:70 and visualized with a MACH 3 polymer kit. The expression was scored as absent (AS‐), or present (AS+) in perikarya or terminals, semiquantitevely rated 1 to 3.ResultsJust over ½ of 70 subjects with no neurological disease were AS+: neither prevalence nor intensity varied by age over 40 years. Differences between sexes were not significative (NS). All 10 PD patients were AS+ as compared to 25 of 54 age‐matched subjects (p< 0.002). The average intensity was also significantly greater (p< 0.002). In contrast 3 of 8 AD cases were AS+ (NS as compared with normal population)ConclusionAS+ in autonomic neurons is common in the adult population. This trait is significantly more prevalent and intense in PD, but not in AD. Either the development of PD increases AS expression, or PD preferentially develops in AS+ subjects
Vascularization fo the cardiac conduction system in humans by the right coronary artery
Authors: Herrera Patricia M , Rojas Adelina , Cichero Carlos F. , Barceló Adrián J. , Arteaga Manuel , Abuin Gustavo 
Published: June 2021

The vascularization of the cardiac conduction system is a topic frequently mentioned and scarcely photographed, the purpose is to demonstrate in pictures the irrigation of the right and left branch of the His bundle ( atrioventricular junctional tissue ) by the superior septal branch of the right coronary artery.Material and MethodTwenty fresh human hearts were perfunded with Microfil ® with the method and dissection previously published by our group.ResultsWe demonstrate with photographs the irrigation of the cardiac conduction system by the right coronary artery in our cases.ConclusionsThis would explain the variation in presentation of the AV block associated with the acute myocardial infarction with the oclusion of the right coronary artery in its origin or near. The importance of this vessel is relevant in Ross technique and other cardiac surgery procedures.
3D‐Micro‐Ultrasound Documents Diltiazem Mediated Changes in Central Aortic Hemodynamics
Authors: Bunzel Michelle M , Campbell Barry , Azer Karim , Tong Christopher , Ramcharan Sharmilee , Saini Kavita , Fancourt Craig , Wang Shubing , Walker Matthew 
Published: June 2021

3D‐micro‐ultrasound imaging has emerged as a valuable research tool to co‐register vascular physiology. This co‐registration allows serial interrogation of arterial wall integrity, blood flow and stiffness. We quantified hemodynamic changes associated with the acute administration of Diltiazem, to benchmark high throughput imaging preclinically.Six male SD rats implanted with DSI pressure probes in the femoral artery were imaged using the VisualSonics Vevo770 (25MHz probe) system. Baseline Doppler measurements in the abdominal aorta were acquired followed by administration of 3mpk Diltiazem i.v. Measurements were then acquired during the acute phase of drug administration and every 5’ over a 60’ time course. Administration resulted in an increase from baseline in cardiac period, diastolic time and Doppler peak‐to‐peak/valley‐to‐valley interval over 60’. Heart rate decreased relative to baseline as did the mean Doppler velocity and max dp/dt (positive/negative). Decreases in systolic BP, diastolic BP, MAP and pulse pressure were also seen.Our novel assessment of the anti‐hypertensive vascular and cardiac effects of Diltiazem is attributable to its primary indication and consistent with the literature. Evaluation of vascular structure and function in real, fiducially aligned, spatial and temporal resolution, unveils a powerful imaging tool for the in vivo characterization of compound efficacy.