bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clinically‐Tested SOD Mimic, MnTnBuOE‐2‐PyP5+, Acutely Decreases Blood Pressure via Sympathoinhibition and Vasodilation
Authors: Schlichte Sarah L. , Park Song-Young , Kosmacek Elizabeth A. , Katsurada Kenichi , Patel Kaushik P. , Oberley-Deegan Rebecca E. , Zimmerman Matthew C. 
Published: April 2020

It is well‐established that reactive oxygen species (ROS), particularly superoxide (O2•−), produced in the vasculature and brain contribute to the pathogenesis of hypertension. We, and others, have previously reported that in vivo scavenging of O2·− via overexpression of superoxide dismutase (SOD) protein or SOD mimics decreases blood pressure in hypertensive animals. While few SOD mimics have transitioned to clinical trials, MnTnBuOE‐2‐PyP5+ (BuOE), a manganese porphyrin SOD mimic, is currently in clinical trials for normal tissue protection in cancer patients exposed to radiation therapy, and thus, provides hope for the use of SOD mimics in the clinical setting. Considering the extensive evidence indicating that scavenging of O2•− decreases hypertensive blood pressures, we tested the hypothesis that the SOD mimic, BuOE, decreases blood pressure in normotensive and angiotensin II (AngII)‐induced hypertensive mice. First, using electron paramagnetic resonance (EPR) spectroscopy and hypoxanthine (HX) + xanthine oxidase (XO) to generate O2•− in a cell‐free system, we confirmed the ability of BuOE to scavenge O2•−. Superoxide produced by HX + XO yielded an EPR spectrum amplitude of 5.6×106 ± 1.3×105 EPR arbitrary units (au), which was significantly (p < 0.05) attenuated by 50 nM BuOE (3.3×106 ± 4.2×104 au). In normotensive and AngII‐induced hypertensive mice, BuOE (1 mg/kg, IP), significantly (p<0.05) decreased mean arterial pressure (MAP), as measured by radiotelemetry, within 25 minutes post‐injection (normotensive ⊗ MAP: vehicle −3.3 ± 2.8; BuOE −27 ± 5.4 mmHg; hypertensive ⊗ MAP: vehicle 3.1 ± 7.2; BuOE −60 ± 14 mmHg). To explore the mechanism(s) by which BuOE decreases MAP, renal sympathetic nerve activity (RSNA) was recorded in normotensive rats injected with BuOE (0.1 mg/kg, IV). Immediately following BuOE injection, RSNA significantly (p < 0.01) decreased by 35 ± 7.0% of baseline, followed by a significant (p < 0.01) decrease in MAP (46 ± 13 mmHg). Additionally, to explore the impact of BuOE on vascular reactivity, video myography was performed on isolated skeletal muscle arterioles from normotensive rats. BuOE (2 μM) induced significant (p < 0.05) vasodilation (31 ± 10%) that was attenuated by pretreating arterioles with the endothelial nitric oxide synthase (eNOS) inhibitor, L‐NAME (1 mM); thus, suggesting that enhanced nitric oxide bioavailability mediates BuOE‐induced vasodilation. Collectively, these data indicate that BuOE, a SOD mimic currently in clinical trials in cancer patients, acutely decreases blood pressure in both normotensive and hypertensive conditions by decreasing sympathetic nerve activity and inducing vasodilation.Support or Funding InformationUniversity of Nebraska Medical Center Graduate Student Assistantship/Fellowship
An Allosteric Site Residue Critical for Transmission of the Allosteric Signal of the Vibrio cholerae SpeG Enzyme
Authors: Marquez-Ramirez Martha , Tran Ha , Kuhn Misty L. 
Published: April 2020

SpeG is a polyamine N‐acetyltransferase enzyme that belongs to the superfamily of Gcn5‐related N‐acetyltransferases (GNATs). We previously showed this enzyme from Vibrio cholerae (VcSpeG) acetylates spermine and spermidine. SpeG is thought to contribute to biofilm formation in several pathogenic bacteria and several studies have shown that it also plays a role in bacterial polyamine homeostasis under stressful conditions. This GNAT is unique because it forms a dodecameric structure and has an allosteric site in each monomer. Additionally, it binds polyamines at both allosteric and active sites. Previous X‐ray crystallographic studies have shown that the E41 residue in the allosteric site of VcSpeG forms a hydrogen bond with N10 of spermine and N6 of spermidine. We hypothesized that mutating this residue would affect the allosteric network of the enzyme. Therefore, we created a series of E41 point mutations and investigated the enzymatic activity and kinetic parameters toward spermine and spermidine. Changing the identity of the residue at this location either increased the catalytic efficiency and altered the sigmoidicity of the substrate saturation curve or decreased the catalytic efficiency and affected cooperativity. This implies that the identity of the residue at this position affects the allosteric signal that is transmitted. Further investigation into other residues in this site is warranted.Support or Funding InformationResearch reported in this work was supported by the National Institute of General Medical Sciences of the National Institutes of Health under Award Number R35GM133506 (to MLK).
Therapeutic Effect of Oridonin Against Inflammatory Bowel Disease Involves Inhibition of Intestinal Fibrosis via NF‐κB Pathway
Authors: Wang Xiaofu , Cummins Claire , Gu Yanping , Song Juquan , Zhou Jia , Radhakrishnan Ravi 
Published: April 2020

IntroductionIntestinal fibrosis and stricture formation are frequent complications of inflammatory bowel disease (IBD). In response to inflammatory stimuli, intestinal epithelial cells may undergo epithelial‐mesenchymal transition (EMT). EMT is a process by which epithelial cells acquire a mesenchymal‐like phenotype, resulting in intestinal fibrosis. Oridonin, a bioactive diterpenoid isolated from Rabdosia rubescens, was reported to have therapeutic effects for IBD. However, the cellular mechanism remains unclear. We hypothesize that oridonin attenuates inflammation‐related EMT and fibrogenesis in intestinal epithelial cells.MethodsIEC‐6 and IEC‐18 cells exposed to TNFα were pre‐treated with or without oridonin. Cellular proteins were analyzed with Western blot or immunofluorescence assay. Cytokine secretion was determined with ELISA.ResultsOridonin treatment suppressed TNFα‐induced NF‐κB activation evidenced by blocking TNFα‐induced NF‐κB p65 nuclear translocation and DNA binding activity. TNFα‐induced phosphorylation of IKKα/β and IκBα as well as total IκBα degradation were prevented by oridonin. TNFα‐stimulated secretion of pro‐inflammatory cytokine IL‐6 was inhibited by oridonin. Oridonin moderately up‐regulates endogenous E‐cadherin and down‐regulates Snail. The expression of extracellular matrix proteins fibronectin and laminin were increased by TNFα and suppressed by pre‐treatment with oridonin. For the first time, we demonstrated that TNFα dose‐dependently up‐regulated α‐smooth muscle actin (α‐SMA), a myofibroblast marker, in IEC‐6 cells. These results indicate that IEC‐6 cells underwent transition into mesenchymal cells after TNFα stimulation. Notably, oridonin inhibited TNFα‐stimulated α‐SMA, but not TGFβ1‐stimulated EMT‐related proteins.ConclusionThe protective effects of oridonin in intestinal epithelial cells may occur through suppression of the TNFα‐induced NF‐κB pathway and EMT‐related fibrogenesis.
SPARC ‐ Mapping Gut‐Spinal Cord Connections in Visceral Pain
Authors: Morrie Ryan David , Bayrer James , Brierley Stuart , Ingraham Holly , Julius David 
Published: April 2020

Our current understanding of mechanisms underlying visceral pain, including that associated with irritable bowel syndrome, remains rudimentary. Importantly, opiates are ineffective at treating visceral pain syndromes, and only exacerbate discomfort by producing constipation, reflecting a clear need for alternative treatment options. Our goal is to bring greater mechanistic insight to this underserved area of pain research, and to approach the problem in a multifaceted strategy designed to maximize the relevance of our basic research discoveries to future pain treatments. Specifically, we are asking how enterochromaffin (EC) cells transmit noxious signals from the gut lumen to the spinal cord. EC cells are key sensory cells in the intestinal epithelium that release serotonin onto primary sensory nerve fibers, thereby evoking a sensation of discomfort and pain in response to luminal irritants, such as bacterial metabolites, inflammatory agents, or ingested chemicals. We are using transgenic moue models to selectively activate and silence EC cells to examine their functional connections with sensory nerve fibers and spinal circuits. We are coupling these tools with transcriptome profiling, viral tracing, and electrophysiological methods to gain insights into the molecular and functional identity of these fibers.Support or Funding InformationNIH R35 NS105038, NIH U01 NS113869, Rainin Foundation, Giannini Foundation
Neck Muscle Morphology and Function in Primates
Authors: McGechie Faye , Grider-Potter Neysa , Nalley Thierra , Fricano Elle , Ward Carol 
Published: April 2020

The cervical spine lies at intersection between the cranium and postcranium and plays a crucial role in orienting the head relative to the substrate during locomotion. Previous work demonstrates that bony features of the cranial base and cervical spine are related to positional behavior in primates. How soft tissues of the neck vary across primate taxa is relatively unknown yet is critical for understanding function, head carriage, and locomotion in this clade. The objective of this study was to describe the relationship between the extrinsic and intrinsic muscles of the neck and postural and locomotor behaviors in primates. We collected and dissected 26 primate cadavers from 17 different genera representing each major primate clade. We hypothesized that trunk and neck posture, as well as forelimb dominated below‐branch suspensory behaviors and neck rotational capabilities all influence the attachment sites and size of the dorsal neck musculature.Using gross anatomical dissection, we qualitatively described and compared the attachment sites of the dorsal neck, back, and shoulder muscles of taxa that display contrasting behaviors and quantified muscle mass. Using the dissection data combined with contrast enhanced microCT data, we constructed 3D models of the head and neck to visualize the in situ neck muscle attachment sites for Propithecus, Aotus, and Carlito.Gross anatomical dissections demonstrate that among nonhuman apes, hylobatids lack cranial attachments of the trapezius and rhomboideus. Additionally, strepsirrhines display anatomy that is more nonprimate mammal‐like in the distribution of the trapezius, rhomboideus, and semispinalis muscles. Results of phylogenetic regressions indicate that neck muscle masses are best predicted by body size, but also demonstrated significant results for both postural and locomotor behaviors as predictors of overall muscle mass (p < 0.05). This study represents the first comprehensive description of the functional anatomy of the neck muscles across primates. Future work will focus on quantifying biomechanically‐relevant variables such as physiological cross‐sectional area using novel fascicle‐tracking methods and estimating muscle moments to compare across taxa.Support or Funding InformationThis work was funded by the Leakey Foundation, National Science Foundation, American Association of Anatomists, Western University of Health Sciences, and University of Missouri.
Consequences of maternal bariatric surgery: potential for reduced amino acid availability to the fetus
Authors: Welch Bradley A. , Himel Alexandra , Duncan Brittany , Spann Redin A. , Grayson Bernadette E. 
Published: April 2020

Though bariatric surgery is the most effect method of durable weight loss, it is not understood why or how it works so effectively to reduce the comorbidities of Metabolic Syndrome. Both in humans and rodents, maternal bariatric surgery prior to pregnancy results in challenges during pregnancy including increased small‐for‐gestational age offspring and greater risk for fetal demise. We have shown in the rodent model of vertical sleeve gastrectomy (VSG) that offspring develop greater risk for metabolic disease later in life compared to obese controls. A common gestational cause of poor growth in utero is maternal protein deficiency. In the current work, we hypothesize that the transporters within the placenta may be differentially transporting amino acids to the fetus despite previously demonstrating that protein levels in the VSG dam were not harmed by surgery and were sufficient to sustain a health pregnancy. Using gestational day 19 placenta from pregnant Lean, Obese and post‐VSG dams, we performed analysis of the amino acid content of the placenta and prepared placental mRNA for quantitative PCR analysis of genes associated with amino acid transport. Aliphatic amino acids: isoleucine, leucine, proline and valine were significantly reduced in comparison to Lean dam levels (p< 0.05). Phenylalanine, aspartic acid and glutamic acid, arginine, histidine and methionine were also significantly reduced (p< 0.05). Furthermore, amino acid transporter SLC38A1 (SNAT1) and SLC38A4 (SNAT4) showed trends towards reductions in both VSG and Obese dams. On the contrary, SLC38A2 (SNAT2) and SLC7a7 (LAT1) was significantly elevated (p< 0.05) in VSG in comparison to Lean and Obese. This affect appeared specific to amino acids since carbohydrate transporters remained unchanged. Collectively, these data suggest that despite healthy ingestion of proteins by the VSG dam, alterations in amino acid availability to the fetus may be obstructed by the placenta after bariatric surgery. This reduced level of amino acid availability may contribute to poor outcomes in bariatric pregnancy. More work is needed to determine the relevance of these findings to humans.Support or Funding InformationResearch was supported by the National Institute of General Medical Sciences of the National Institutes of Health under Award Number P20GM104357 and P20GM121334.
Effect of Superior Cervical Gangionectomy on the Chemoreflex Response to Hypoxia in the Rat Carotid Body
Authors: Getsy Paulina M. , Coffee Gregory A. , Liu Yehe , Owens Joy , Jenkins Michael W. , Lewis Stephen J. 
Published: April 2020

Carotid body (CB) chemosensitive glomus (type I) cells respond to decreases in blood pO2 (hypoxia) by releasing neurotransmitters, which in turn activate adjacent chemosensory afferent fibers within the carotid sinus nerve (CSN). These CSN chemoafferents then signal to the commissural nucleus tractus solitarius (cNTS) within the dorsal brainstem, which leads to a compensatory increase in ventilation in order to restore blood‐gas homeostasis. The CB receives sympathetic innervation via the ganglioglomerular nerve (GGN), whose cell bodies reside in the superior cervical ganglion (SCG). We have found that electrical stimulation of the GGN causes an increase in CB chemosensory afferent discharge. However, it is unknown the effect removing the carotid body’s sympathetic innervation, via superior cervical ganglionectomy, will have on the carotid body’s chemoreflex response to hypoxia. We hypothesize that loss of sympathetic input will decrease the hypoxic ventilatory response (HVR) of the rat, and alter the O2‐sensing mechanism of the CB chemosensitive glomus cells. Sprague Dawley male rats postnatal day 21 were subjected to unilateral or bilateral superior cervical ganglionectomy (SCGX). Four days post surgery (post‐natal day 25), rats either underwent whole body plethysmography recordings or were sacrificed and their carotid bodies removed to either isolate glomus cells and perform whole cell perforated patch clamp, or perform immunohistochemistry on the CB. Our preliminary results show that unilateral (left or right) SCGX appears to decrease the HVR during a 1‐minute exposure to hypoxia (10% O2, 90% N2) compared to bilateral SCGX. Our results also show that following SCGX, isolated glomus cells responded to acute hypoxia (HX) (5–8% O2, 5% CO2, balanced N2) with significant reductions (P<0.05 to P<0.01) in outward K+ current amplitudes over the test potential range +10 to +60 mV. The mean maximal effect, a reduction in K+ amplitude of 64.9 ± 18.5% (mean ± SD, n = 3 cells), occurred at a Vtest of +30mV. In contrast, control carotid body glomus cells responded to acute HX with a significant reduction (P<0.05) in outward K+ current amplitude at a Vtest of +60mV (n = 4 cells). In conclusion, our data suggests that sympathetic innervation to the CB is critical for the ventilatory response to hypoxia, and the O2‐sensing mechanism at the level of the CB glomus cells. Overall this study provides novel evidence for the importance of sympathetic innervation on peripheral chemosensors during exposure to hypoxia.Support or Funding InformationThis work was supported in part by a SPARC NIH award OT2OD023860
Human Red Blood Cell Uptake and Sequestration of Arsenite and Selenite: Evidence for the Formation of a Protective Glutathione Conjugate
Authors: Leslie Elaine M. , Kaur Gurnit , Javed Warda , Ponomarenko Olena , Swanlund Diane P. , Hu Michael , Summers Kelly L. , Casini Angela , Wenzel Margot , Casey Joseph R. , Cordat Emmanuelle , Pickering Ingrid J. , George Graham N. 
Published: April 2020

Over 200 million people worldwide are exposed to the proven human carcinogen, arsenic, in contaminated drinking water. In laboratory animals, arsenic and the essential trace element, selenium, can undergo mutual detoxification through the formation of the seleno‐bis(S‐glutathionyl) arsinium ion [(GS)2AsSe]−, which undergoes biliary and fecal elimination. [(GS)2AsSe]−, formed in animal red blood cells (RBCs), sequesters arsenic and selenium, and likely slows the distribution of both metalloids to the liver, and other organs susceptible to toxic effects. In human RBCs, the influence of arsenic on selenium accumulation, and vice versa, is largely unknown. The aims of this study were to characterize arsenite (AsIII) and selenite (SeIV) uptake by human RBCs, to determine if SeIV and AsIII increase the respective accumulation of the other in human RBCs, and ultimately to determine if this occurs through the formation and sequestration of [(GS)2AsSe]−. 75SeIV accumulation was inhibited by 4,4′‐diisothiocyanatodihydrostilbene‐2,2′‐disulfonic acid (H2DIDS) (IC50 1 ± 0.2 μM), suggesting uptake is mediated by the erythrocyte anion‐exchanger 1 (AE1 or Band 3, gene SLC4A1). HEK293 cells overexpressing AE1 showed concentration‐dependent 75SeIV uptake. 73AsIII uptake by human RBCs was temperature‐dependent and partly reduced by aquaglyceroporin 3 inhibitors. AsIII increased 75SeIV accumulation (in the presence of albumin) and SeIV increased 73AsIII accumulation in human RBCs. Near‐edge X‐ray absorption spectroscopy revealed the formation of [(GS)2AsSe]− in human RBCs exposed to both AsIII and SeIV. The sequestration of [(GS)2AsSe]− in human RBCs potentially slows arsenic distribution to susceptible tissues and could reduce arsenic‐induced disease.Support or Funding InformationCanadian Institutes of Health Research, Canada Research Chairs program, Natural Science and Engineering Council of Canada
Barreling Forward: Advancements in De Novo Protein Design
Authors: Kohli Khushi , Liu Samuel , Garapaty Arjun , Dai Eddie 
Published: April 2020

Natural evolution and protein redesign have only explored a tiny fraction of theoretically possible protein structures. However, de novo protein design will prove powerful in engineering novel proteins with specific functions by comprehensively sampling the protein space using computational methods guided by protein folding principles. De novo protein design involves working backwards from a desired protein with special structure and function to derive an amino acid sequence capable of folding into such a conformation—a challenging approach due to the vast number of protein conformations to evaluate. Here, we present a review of the latest advancements in de novo protein design methods and applications in conjunction with a physical model of a de novo fluorescence‐activating β‐barrel protein. Approaches to de novo protein design include: (1) simulating the folding of a fixed amino acid sequence to determine each residue’s most stable conformation, (2) determining the amino acid sequence that folds into a desired protein conformation, and (3) performing comprehensive rapid evaluations of each possible conformation. This novel protein is then synthesized and validated through in vitro or in vivo assays. In one recent breakthrough by Baker et. al., a de novo approach was used to design a β‐barrel protein comprised of a cylindrical pleated β‐sheet which binds the fluorogenic compound DFHBI. This study is the first instance of a de novo protein designed to bind to a small molecule of interest, with applications in visualizing cell movement, gene expression, DNA replication, protein translation, and tumor progression. In designing this fluorescence activating β‐barrel protein, structural irregularities were introduced to stabilize the structure and enlarge the β‐barrel cavity. Subsequently, the optimal sequences for β‐barrels with reasonable binding site and affinity for DFHBI were designed by computationally adjusting individual residue conformations. Finally, this optimized protein was synthesized, which had greater affinity with DFHBI and increased fluorescence in in vitro and in vivo experiments.Support or Funding InformationThis is a SMART Team project supported through the contributions of Dr. Jinan Wang of the University of Kansas Center for Computational Biology, the Milwaukee School of Engineering, and the Olathe Medical Professions 21st Century Academy.