bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of endothelial nitric oxide in control of peripheral vascular conductance during muscle metaboreflex activation
Authors: Senador Danielle , Kaur Jasdeep , Alvarez Alberto , Hanna Hanna W. , Krishnan Abhinav C. , Altamimi Yasir H. , O'Leary Donal S. 
Published: November 2023

The muscle metaboreflex is a powerful pressor reflex induced by the activation of chemically sensitive muscle afferents as a result of metabolite accumulation. During submaximal dynamic exercise, the rise in arterial pressure is primarily due to increases in cardiac output as there is little systemic vasoconstriction. Indeed, in normal animals we have shown a small, but significant, peripheral vasodilation during metaboreflex activation which is mediated at least in part by release of epinephrine and activation of vascular β2 receptors (Kaur et al., Am. J. Physiol. Heart Circ., 2015). We tested whether this vasodilation is in part due to increased release of nitric oxide caused by the rise in cardiac output eliciting endothelium‐dependent flow‐mediated vasodilation. The muscle metaboreflex was activated via graded reductions in hindlimb blood flow during mild exercise with and without nitric oxide synthesis blockade (L‐nitroarginine methyl ester (L‐NAME); 5mg/kg). We accessed the role of increased cardiac output in mediating peripheral vasodilation via the slope of the relationship between the rise in non‐ischemic vascular conductance (conductance of all vascular beds excluding hindlimbs) vs. the rise in cardiac output. L‐NAME increased mean arterial pressure at rest and during exercise. The metaboreflex‐induced increases in mean arterial pressure were unaltered by L‐NAME; whereas, the increases in cardiac output and non‐ischemic vascular conductance were attenuated. However, the slope of the relationship between non‐ischemic vascular conductance and cardiac output was not affected by L‐NAME indicating that the rise in cardiac output did not elicit vasodilation via increased release of nitric oxide. Thus, although nitric oxide is intrinsic to the vascular tonus, endothelial‐dependent flow‐mediated vasodilation plays little role in the small peripheral vasodilation observed during muscle metaboreflex activation.Support or Funding Information(NIH HL55473)
Crystal structure and mutagenesis studies of mammalian fucosyltransferase‐9 (FUT9) reveals the catalytic core and substrate specificity
Authors: Boruah Bhargavi M , Kadirvalraj Renu , Wang Shuo , Ramiah Annapoorani , Wood Zachary A , Moremen Kelley W 
Published: November 2023

Mammalian fucosyltransferases (FUTs) fall into 5 CAZy families, all of which employ GDP‐Fucose as a sugar donor, but each has a unique acceptor specificity. FUT9 is one of the several α1,3‐fucosyltransferases in CAZy GT10, which catalyzes the last step in the biosynthesis of Lewis X antigen by addition of a fucose residue to precursor glycan structures. Recombinant expression and purification of soluble glycosyltransferases for biochemical and structural characterization has been a challenge, since these enzymes require efficient glycosylation and disulphide bonding for correct folding and function. In our study, we employ a mammalian cell expression platform for generation of soluble, secreted forms of glycosylation enzyme catalytic domains in large scale for structural and functional studies of these enzymes. Based on this approach, we report the 1.2 Å crystal structure of mammalian FUT9 catalytic domain that highlights elements of substrate specificity and catalysis. FUT9 has been co‐crystallized with GDP and lacto‐N‐neotetraose (LNnT) to reveal details of the binding sites for the donor and the acceptor, respectively. Enzymatic characterization of wild type and mutant forms of FUT9 using a collection of acceptor substrates have correlated the positions of active site residues with their contributions to catalysis and acceptor specificity. Together, these results provide insights into the enzyme structure and details of substrate interactions and specificity.Support or Funding InformationThis study is supported as an ARRA and administrative supplement to NIH NCRR grant RR005351 and P01GM107012
The Impact of AB5 Toxin Binding on Ganglioside Mimicry in Campylobacter jejuni Lipooligosaccharides
Authors: Patry Robert T , Stahl Martin , Sacher Jessica , Vallance Bruce A , Szymanski Christine M 
Published: November 2023

Campylobacter jejuni is an important pathogen in the developed world, causing more cases of acute gastroenteritis than any other bacteria. C. jejuni is also the leading cause of paralysis in the world, causing Guillain‐Barré syndrome in humans by mimicry of nerve gangliosides with its surface exposed lipooligosaccharides (LOS). In some cases this mimicry elicits a breakdown in immune tolerance and results in self‐reactive antibodies which damage the nerve cells. Interestingly, the commonly mimicked GM1 ganglioside is also the main receptor for cholera toxin (CT) from Vibrio cholerae as well as heat‐labile enterotoxin (LT) from Escherichia coli. We have shown that these two toxins bind C. jejuni strains that mimic GM1 ganglioside and clear bacterial growth. The binding and clearing phenotypes were observed closely using transmission and scanning electron microscopy. C. jejuni 11168 shows natural variation in its ability to mimic GM1 gangliosides. Due to phase‐variation in cgtB encoding the galactosyltransferase, this strain exists as a mixture cells with and without GM1 mimics. It was unclear why the strain retained this variation, given that mimicry of host gangliosides lends a significant fitness advantage by camouflaging the bacterium from host immune defenses. Therefore, LOS was isolated from 11168 exposed to CT and LT toxin and compared to the unexposed by silver staining and far Western blotting. These experiments revealed the loss of a band from toxin exposed LOS and a marked decrease in the ability to bind toxin. Furthermore, when genomic DNA was isolated from these two groups and the cgtB gene was sequenced, the variation that existed in the unexposed group was no longer observed in the presence of the toxins. This led to the hypothesis that C. jejuni 11168 may retain variation in the cgtB gene in order to avoid negative effects upon contact with these toxins in the host or the environment. In addition, when we used a strain of E. coli engineered to display the GM1 mimic on its surface, no clearance was observed suggesting that this interaction is pathogen specific. Our study identifies a new interaction between C. jejuni and the AB5 toxins that has not been previously described and provides a possible new relationship within the intestinal microbiome.Support or Funding InformationFunding provided by the Natural Sciences and Engineering Research Council of Canada, Alberta Innovates Technology Futures and Alberta Innovates Health Solutions.
The Antibiotic Activity of Tea Tree, Eucalyptus, and Cinnamon Bark Oils
Authors: Rohraff Dallas , Morgan Roderick 
Published: November 2023

The emergence of antibiotic resistant bacteria is of pressing concern, especially given that the pharmaceutical industry has decreased funding for infectious disease drug discovery programs. It is estimated that over 2 million people are infected with antibiotic resistant strains of bacteria each year, resulting in over 23,000 deaths. Researchers are currently looking for novel antibiotics in alternative sources. Essential oils, derived from plants, are an ancient homeopathic remedy that are traditionally known to have antimicrobial properties. Therefore, several essential oils were examined in search of novel antibiotics. Tea tree (Melaleuca alternifela), eucalyptus (Eucalyptus globulus), and cinnamon bark (Cinnamomum cassia Blume) oils showed antibiotic activity in Kirby‐Bauer disk diffusion assays. The Minimum Inhibitory Concentration (MIC) values for tea tree, eucalyptus, and cinnamon bark oils were determined to be 1.25%, 0.313%, and 0.0391%, respectively. All three oils proved effective against both Gram‐positive Staphylococcus aureus and Gram‐negative Escherichia coli. Cinnamon bark oil was the most effective and was further characterized. Cinnamon bark oil retained its MIC in the presence of 10% human serum protein, indicating that it does not interact with proteins in the bloodstream. Cinnamon bark oil showed bactericidal activity in a time kill assay. To determine the active component within cinnamon bark oil, an analysis of its constituents was conducted. Three of the main components of cinnamon bark oil, trans‐cinnamaldehyde, cinnamyl cinnamate, and benzyl cinnamate, were subjected to preliminary testing via Kirby‐Bauer disk diffusion tests. Trans‐cinnamaldehyde appeared to be the only effective component against both S. aureus and E. coli. Results suggest that cinnamon bark oil may contain a promising novel antibiotic.Support or Funding InformationThis research was supported by Grand Valley State University's Student Summer Scholars program.
Decreased Insulin Signaling Causes Loss of Cardiac PFK‐2 in Diabetes
Authors: Bockus Lee , Humphries Kenneth 
Published: November 2023

Cardiac 6‐phosphofructo‐2‐kinase/fructose‐2,6‐bisphosphatase (PFK‐2; PFKFB2), a central metabolic enzyme that regulates glycolysis in the heart, is regulated by insulin and adrenergic signaling. Although phosphorylation is known to increase its kinase activity, it is unknown whether insulin signaling and diabetes also affects its content and thus its active capacity. This is critical to know because PFK‐2 content can have a significant impact on cardiac metabolic flexibility. We therefore employed multiple mouse and primary cardiomyocyte models with deficient insulin signaling. In streptozotocin‐induced type I diabetic mice we found a 70% decrease in PFK‐2 protein content. Further, the remaining PFK‐2 is not phosphorylated by activation of PKA in vivo. A reduction in cardiac PFK‐2 content also occurs with overnight fasting and a high fat diet mouse model of type II diabetes. By metabolomic analysis, fructose‐6‐phosphate is elevated 3‐fold with 24h fasting and 3‐phosphoglycerate is reduced 50%, suggesting glycolysis is blocked at phosphofructokinase‐1. No difference was found in AMP levels or citrate, indicating that the reduced content and activity of PFK‐2 is a primary reason glycolysis is impeded in the fasting state. The loss of PFK‐2 can be recapitulated in adult mouse cardiomyocytes by the removal of insulin from media or supplementation with lipids, both of which reduce Akt‐mediated phosphorylation. Inhibition of insulin signaling in cardiomyocytes by wortmannin, a PI3K inhibitor, causes a marked loss of PFK‐2 with a half‐life of 2 hours. In summary, reduced insulin signaling in the heart in both types of diabetes and fasting results in PFK‐2 degradation and impaired glycolysis.Support or Funding InformationResearch reported in this study was supported in part by an Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health (P20GM104934), by the Oklahoma Center for the Advancement of Science and Technology (HR13‐183), and by the American Heart Association (14GRNT20510031).
A role of NMDA receptors in regulating KATP and Kv2.1 channel trafficking in pancreatic β‐cells
Authors: Chen Pei‐Chun , Wu Yi , Ruan Jing‐Syuna , Shyng Show‐Ling 
Published: November 2023

Leptin secreted from adipocytes is known to act on pancreatic β‐cells directly to suppress insulin secretion. We recently showed that leptin reduces β‐cell excitability by promoting surface expression of both KATP and Kv2.1 channels in β‐cells via a signaling mechanism involving AMPK and its upstream kinase CaMKKβ. However, how leptin activates the CaMKKβ/AMPK signaling axis remains unclear. Here we tested the hypothesis that NMDA receptors, which are permeant to Ca2+, may be involved. Using the insulinoma INS‐1 cells, we show that the NMDA receptor antagonists MK‐801 or AP‐5 blocked the effect of leptin on both KATP and Kv2.1 channels; conversely, the receptor agonist NMDA alone is sufficient to recruit KATP and Kv2.1 channels to the β‐cell membrane. The effects of the NMDA receptor agonist and antagonists on KATP and Kv2.1 channels corresponded with their effects on pAMPK levels, indicating that the involvement of NMDA receptors is downstream of leptin but upstream of AMPK. Western blots confirmed that INS‐1 cells indeed express the obligatory NMDA receptor subunit GluN1. Electrophysiological recording further demonstrated the presence of NMDA evoked currents in INS‐1 and human β‐cells. Our findings suggest that NMDA receptors are important for mediating the effect of leptin to regulate trafficking of Kv2.1 and KATP channels in β‐cells.Support or Funding Information(Supported by NIH R01DK057699 to SLS and MOST 1032320B006005MY2 to PCC.)
Inhibitors of Ribosome Rescue Arrest Growth of Francisella tularensis at All Stages of Intracellular Replication
Authors: Goralski Tyler D.P. , Dewan Kalyan K. , Alumasa John N. , Avanzato Victoria , Place David E. , Markley Rachel L. , Katkere Bhuvana , Rabadi Seham M. , Bakshi Chandra Shekhar , Keiler Kenneth C. , Kirimanjeswara Girish S. 
Published: November 2023

Francisella tularensis ssp. tularensis is a gram‐negative, facultative intracellular bacterium, which is classified as a Tier 1 Select Agent by the CDC due to its high infectivity and ease of propagation. Attempts to develop an effective vaccine have been unsuccessful, due in part to the organism's ability to suppress or bypass the host immune response early after infection. F. tularensis strains resistant to multiple antibiotics are a biowarfare threat. In the absence of an effective vaccine, new antibiotic targets and compounds are needed to ensure biodefense. Bacteria require at least one pathway to rescue ribosomes stalled at the end of mRNAs. The primary pathway for ribosome rescue is trans‐translation, which is conserved in >99% of sequenced bacterial genomes. Some bacterial species also have backup systems, such as ArfA or ArfB, which can rescue ribosomes in the absence of sufficient trans‐translation activity. Small molecule inhibitors of ribosome rescue have broad‐spectrum antimicrobial activity against bacteria grown in liquid culture. These compounds were tested against F. tularensis to determine if they can limit bacterial proliferation during infection of eukaryotic cells. The inhibitors KKL‐10 and KKL‐40 exhibited exceptional antimicrobial activity against both attenuated and fully virulent strains of F. tularensis in vitro and during ex vivo infection. Addition of KKL‐10 or KKL‐40 to macrophage or liver cells at any time after infection by F. tularensis prevented further bacterial proliferation. When macrophages were stimulated with the pro‐inflammatory cytokine interferon‐γ before being infected by F. tularensis, addition of KKL‐10 or KKL‐40 reduced intracellular bacteria by >99%, indicating that the combination of cytokine induced stress and a nonfunctional ribosome rescue pathway is fatal to F. tularensis. Neither KKL‐10 nor KKL‐40 were cytotoxic to eukaryotic cells in culture. These results demonstrate that ribosome rescue is required for F. tularensis growth at all stages of its infection cycle, and suggest that KKL‐10 and KKL‐40 will be good lead compounds for antibiotic development.Support or Funding InformationThis work was supported by NIH (AI077917 to Girish S. Kirimanjeswara and GM068720 to Kenneth C. Keiler) and CAS/PSU start up funds to Girish S. Kirimanjeswara. The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Microparticle analysis of clinical plasma samples using acoustic trapping
Authors: Bryl‐Gorecka Paulina , Sathanoori Ramasri , Gidlöf Olof , Svensson Siv , Evander Mikael , Laurell Thomas , Olde Bjorn , Erlinge David 
Published: November 2023

ObjectiveEndothelial dysfunction, inflammation and platelet activation are conditions that predispose for development of cardiovascular disease. These are also conditions previously shown to trigger release of microparticles (MPs). As isolation of MPs from plasma is time consuming and requires large sample volumes, we decided to develop an alternative method based on acoustic trapping. Acoustic trapping is a non‐contact method where sound waves are used to retain particles in a microfluidic channel (Figure 1). Exciting a capillary with a piezoelectric transducer that creates a local acoustic standing wave field will enable trapping and clustering of particles in this zone. Submicron particles can subsequently be trapped on the larger particles by inter‐particle acoustic forces, so called “seed trapping”. As a test of the method we analyzed the change in endothelial MPs (EMPs) release that was stimulated by physical excersise in healthy controls and subjects with coronary artery disease.Methods
Patient and control samples: 8 patients with history of coronary artery disease and 5 healthy subjects underwent physical exercise (cycling). Blood samples were collected into EDTA tubes before and 1h after exercise. The samples were centrifuged at 1,600 × g for 15 minutes and then stored at −80°C.
Isolation of MPs: Plasma samples were subjected to centrifugation (2 times 1600 × g, 15 min, 4°C) in order to obtain platelet‐free plasma. 25 ul of sample was aspirated and the microparticles were trapped and subsequently eluted in 100 ul PBS.
Staining of CD62E (E‐selectin)+ EMPs: The microparticles were stained with 3 ul of PE‐conjugated anti‐CD62E antibody for 45 min at room temperature, in the dark with constant shaking, followed by FACS analysis using a BD Accuri C6 cytometer.
ResultsCD62E+ MPs ranged from 25 to 77 and 20 to 62 events/ul for patients and controls respectively. A decrease in numbers of CD62E+ MPs was observed 1 h after exercise for both patient and control samples. This decrease was present in both groups, but it was more pronounced in the patients.ConclusionsAcoustic trapping technique may be used for isolation of MPs, including EMPs, from human plasma. The presented results indicate an anti‐inflammatory effect of physical exercise on the endothelium.Support or Funding InformationSwedish foundation for strategic research
Cellular and molecular components regulating social behaviour of male Drosophila
Authors: Kim Woo Jae , Jan Lily Yeh , Jan Yuh Nung 
Published: November 2023

Environmental conditions, such as the socio‐sexual context, can change rapidly. In these circumstances, the ability of animal of a genotype to express a different phenotype according to the environment can improve survival and reproductive success. A primary function of males for many species involves mating with females for reproduction. For males, current mating investment can often be subject to trade‐offs with future mating opportunities to maximize fitness in a rapidly changing socio‐sexual environment. Males have a finite resource for reproduction; hence a ‘time investment strategy’ has evolved to maximize reproductive success. Drosophila males respond to the presence of rivals by prolonging mating duration to increase the chance of passing on genes. In previous studies, we examined the genetic network and neural circuits that regulate rival‐induced longer mating duration (LMD). LMD can be induced solely via visual stimuli. LMD depends on the circadian clock genes timeless and period, but not Clock or cycle. LMD involves the memory circuit of the ellipsoid body (EB). Further, we identified a small subset of clock neurons in the male brain that regulate LMD via neuropeptide signaling.More recently, we investigated a novel behavioral plasticity whereby male fruit flies exhibit a shortened mating duration when sexually satiated, called ‘Shorter‐Mating‐Duration (SMD)’. Both sexual experiences and contact‐based chemoreception is necessary to induce SMD. SMD requires the sexually dimorphic Gr5a‐positive neurons to detect female body pheromones, and can be induced by gustatory stimuli. The memory circuitry within the ellipsoid body (EB) and mushroom body (MB) brain regions is crucial to process this satiety state. SMD depends on the circadian clock genes Clock and cycle, but not timeless or period. SMD also relies on signaling via the neuropeptide sNPF, but not PDF or NPF. Sexual experience modifies the neuronal activity of a subset of sNPF‐positive neurons involved in neuropeptide signaling, which modulates SMD. Thus, our study delineates the molecular and cellular basis for SMD – a plastic social behavior that can be modified by sexual experience.Our studies delineate part of the molecular and cellular basis of plastic behaviors elicited by different socio‐sexual environments. LMD together with SMD can be a model to study how the socio‐sexual environment affects on male behavioral plasticity via neural circuitry.Support or Funding InformationHHMINIH R01University of Ottawa Startup grant
Postprandial Hypertriglyceridemia‐induced Brain Vascular Inflammation by Next‐Generation Sequencing
Authors: Nyunt Tun , Wilson Dennis W. , Rutledge John C. , Aung Hnin H. 
Published: November 2023

Vascular dementia (VaD), the second most common form of dementia, is associated with vascular risk factors, such as hyperlipidemia. The pathophysiological mechanisms and potential therapies for VaD are poorly understood; however, previous studies suggest a relationship of blood lipids and/or lipoproteins to vascular inflammation leading to dementia.The objective of this study is to characterize brain endothelial cell responses to postprandial triglyceride‐rich lipoproteins (TGRL) and determine the pathways that have potential to increase risk for vascular dementia.To address this question, we treated human brain microvascular endothelial cells (HBMVEC) with TGRL lipolysis products and then we used next‐generation sequencing (NGS)‐based RNA sequencing (RNA‐Seq) methods for transcriptional profiling experiments. Genome‐wide analyses of transcription of single nucleotides were generated on the Illumina HiSeq3000 sequencer. We then identified regulatory genes and their targets in RNA‐Seq datasets that have been differentially expressed using TopHat mapper and EdgeR statistical software packages. The Grinn software tool was used to retrieve pathway annotations of significant genes. The R package Piano was used for pathway enrichment analysis.System biology analysis showed that TGRL lipolysis products activated 108 signaling pathways of which 48 signaling pathways were significantly activated. Among them, the most significant (p value=0) activated signaling pathways were MAPK (20 up‐regulated and 4 down‐regulated genes), TNF (16 up‐regulated and 4 down‐regulated genes) and Influenza A (10 up‐regulated and 4 down‐regulated genes). Stress response related genes (activating transcription factor 3 (ATF3), ATF4, Jun dimerization protein 2, sestrin 2, growth arrest and DNA damage inducible alph, DNA damage inducible transcript 3 (DDIT3) and DDIT4) and inflammatory response related genes (CCAAT/enhancer binding protein beta (CEBPB), VEGFA, gamma‐glutamylcyclotransferase 1, and TNF superfamily member 18, IL‐1 alpha) were up‐regulated and confirmed by qRT‐PCR analysis.System biology analysis has led to the validation of putative lipid‐related targets and the discovery of 510 genes and corresponding isoforms that may be implicated in hypertriglyceridemia‐induced vascular inflammation in brain. Furthermore, the results of RNA‐Seq determined specific isoforms of key transcriptional regulator ATF3 and stress response signaling pathway in lipolysis product‐mediated brain vascular inflammation which may lead to vascular dementia.Support or Funding InformationNIH‐NIA AG045541, NIH‐NIA AG039094, Richard A. and Nora Eccles Harrison Endowed Chair in Diabetes Research.