bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ex‐vivo Effects of Limonene in Airways and Vasculature in Allergic Adenosine A2A receptor Knock‐out and Wild‐type mice
Authors: Rajalingam Sahith , Bhavsar Riya , Patel Mehaben , Mustafa S. Jamal , Ledent Catherine , Ponnoth Dovenia S. 
Published: April 2020

Limonene, a mono‐terpene flavonoid, has anti‐inflammatory effects in asthma by activating A2A adenosine receptors. We studied the effects of inhaled d‐limonene on isolated aortic and tracheal rings from asthmatic mice using tissue/organ bath system. We used mice in which the A2A receptor was genetically knocked out (A2AKO) and C57BLJ/6 (wild‐type; WT) for the study. The mice were divided into control (CON) and allergen‐induced sensitized (SEN), control mice treated with limonene through aerosol route (CON+LIM) and allergen‐induced sensitized mice treated with limonene (SEN+LIM). Mice were sensitized i.p. on days 1, 6 with 20μg ovalbumin (OVA) followed by 5% OVA aerosol challenges on days 11–13. Control groups were given an i.p injection of vehicle (1,6 days) and the aerosol challenge of normal saline (11–13 days). SEN +LIM and CON +LIM groups were given 0.01% limonene in the form of aerosol 90 min prior to the OVA and saline challenge on days 11,12,13. Trachea and aorta were isolated on day 14 for further experiments. Tissue responses were studied in the form of contraction and relaxations in all groups. Treatment with limonene significantly reduced the tracheal reactivity (80.68±20% in SEN+LIM vs SEN; p<0.05) to methacholine (MCh) in WT mice that were allergic. MCh induced tracheal contractions were not altered in A2AKO limonene treated sensitized group compared to non‐treated A2AKO sensitized group (209.87 ± 41.33 A2AKO SEN+LIMSEN+LIM Vs 212.51 ± 43.18 in A2AKO SEN) In presence of A2A‐antagonist (SCH58651), a significant increase in the MCh induced contractility in WT SEN was observed(341.65 ± 2.664 SEN+SCH Vs 225.99 ± 67.34 SEN, pP<0.05). A2A agonist CGS 21680 induced relaxation in WT CON was abolished in WT SEN but restored in WT SEN+LIM (37.8± 16.4% Vs 1.2± 11.1 in SEN, p<0.05). The CGS‐induced tracheal relaxation in WT SEN+LIM and SEN groups was increased in the presence of the NADPH inhibitor apocynin (60.58 ± 17.20 SEN; 21.28 ± 16.02 SEN). In the aorta, acetylcholine‐induced aortic relaxation (endothelium‐dependent response) in WT SEN group was significantly lower than controls (29.82 ± 5.62 WT SEN Vs 51.51 ± 30.13 WT CON, p<0.05) with limonene restoring the response (61.56 ± 11.34 WT‐SEN+LIM). CGS 21680 induced aortic relaxation in WT SEN was completely blunted compared to WT CON (5.62±3.72 WT SEN Vs 66.91 ± 6.8 WT‐CON, *p<0.05). Treatment with limonene restored CGS 21680‐induced relaxation in asthmatic mice (63.8 ± 6.32 WT SEN+LIM Vs 5.62± 3.72 SEN) In conclusion, it appears that limonene restores the tracheal and aortic relaxation induced by adenosine‐mediated pathways by activating the A2A receptor in asthmatic mice.Support or Funding InformationSupported by LIU start‐up funds (DSP), HL027339 (SJM)
Mechanisms of Pisiform Reduction in Mammals
Authors: Kjosness Kelsey M. , Gavazzi Lia M. , Reno Philip L. 
Published: April 2020

Most mammalian pisiforms are large, elongated carpal bones with two ossification centers and an associated growth plate, similar to the calcaneus in the ankle. Short pisiforms are rare among mammals, but can be found in humans, orangutans (Primates: Pongo sp.), two‐toed sloths (Pilosa: Choloepus sp.), and three‐toed sloths (Pilosa: Bradypus sp.). These groups utilize diverse forms of locomotion; humans are bipedal, orangutans are quadrumanous climbers, and sloths are suspensory quadrupeds. Human pisiforms form from a single ossification center and have likely lost a primary ossification center and the associated growth plate. Given the rarity of short pisiforms among mammals, little is known about the functional implications or developmental mechanisms underlying this convergent morphology in species with such diverse locomotor modes and evolutionary histories. The purpose of this study is to compare ossification patterns in orangutans and sloths with the mechanism underlying human pisiform truncation. We compare pisiform ossification data from human, orangutan, and sloth museum specimens. Unlike humans, orangutan pisiforms retain two centers of ossification but appear to form the secondary center of ossification later than other apes, possibly shortening the growth period for the pisiform. Sloths form a primary center of ossification with an unusual, pitted surface, which may represent an abnormal subchondral surface. In non‐human primates (including orangutans) and giant anteaters (Pilosa: Myrmecophaga tridactyla), which represent the closest living taxonomic group to sloths, pisiform and calcaneus ossification is generally correlated with epiphyses forming at similar times within individuals. In contrast, we found only a single ossification center corresponding to sloth pisiforms at all stages of calcaneal epiphyseal formation. Thus, the single pisiform ossification center appears to precede calcaneal epiphysis formation. This indicates that the sloth pisiform is homologous to the primary center of ossification of the calcaneus and other mammalian pisiforms, and that it fails to form a secondary center. This is in contrast to human pisiforms, which fail to form the primary ossification center. Humans, orangutans, and sloths are all unusual among mammals for having short pisiforms and each group achieves pisiform reduction through unique mechanisms.Support or Funding InformationThis research was funded by the National Science Foundation (BCS‐1540418 and BCS‐1638812).
The effects of Gtf2i and Gtf2ird1 mutations on the skull in Williams‐Beuren Syndrome
Authors: Hill Cheryl A. , Kirkland Nicole M. , Kopp Nathan D. , Dougherty Joseph D. 
Published: April 2020

Williams‐Beuren syndrome (WBS) is a neurodevelopmental disorder caused by a 1–8 Mbp deletion on chromosome 7. In addition to hypersocial personalities and visuospatial changes, individuals with WBS also show changes in cardiovascular and craniofacial phenotypes. GTF2I AND GTF2IRD1 have been implicated in producing the changes seen in the craniofacial phenotype. The purpose of this study is to determine if Gtf2ird1 and Gtf2i interact to produce craniofacial features associated with WBS in mouse models.Using CRISPR/CAS9 technology, we developed two new mouse models loss‐of‐function mutations in both Gtf2ird1 and Gtf2i and wildtype littermates. The study sample includes computed tomography scans acquired from the skulls of mice with differing number of mutations in these genes and their wildtype littermates (N=119). Three‐dimensional landmark coordinate data were collected from scans of the skull and analyzed using geometric morphometrics.Skulls of mice with only one loss‐of‐function mutation in Gtf2ird1 were not different from wildtype littermates, while mutations in both Gtf2i and Gtf2ird1 show variable results across the two models. Our results indicate that loss‐of‐function mutations in Gtf2ird1 and Gtf2i interact in nuanced ways to affect the craniofacial structure in these mouse models for Williams‐Beuren syndrome. Varying protein expressions within these mice, interactions with other genes in the deleted region of chromosome 7 and other factors lead to changes in the craniofacial phenotype seen in Williams‐Beuren syndrome.Support or Funding Information5R01MH107515‐03 to JDD, NSF fellowship DGE‐1745038 to NDK.
Variants of Mre11 induce genomic instability
Authors: Hilton Austin , Gunning Abigail , Kuehn Sydney , Shanle Erin , Ray Sreerupa 
Published: April 2020

DNA double‐strand break (DSB) is the most lethal type of DNA damage and if not properly repaired could destabilize the genome. Cells repair DSBs by three repair pathways‐homology‐directed repair (HDR), non‐homologous end‐joining (NHEJ) and a recent back‐up NHEJ pathway has been reported and is referred to as alternate‐NHEJ (Alt‐NHEJ). Mre11 plays a role in all the three DSB repair pathways. Mre11 has single‐strand endonuclease activity and double‐strand‐specific 3′–5′ exonuclease activity which are essential for DNA end‐processing. Mre11 has been shown to be overexpressed in breast cancer and high Mre11 expression was found to be associated with a more malignant behavior in breast cancer. Mutations in Mre11 genes can have a significant impact on cancer prognosis and treatment. Here we show that cells expressing variants of Mre11 are sensitive to DNA damaging agent etoposide. We also found that the Mre11 variants influence response to various DNA damaging agents and induce genomic instability. Work is on‐going to characterize how the Mre11 variants alter DSB repair mechanisms. This will provide mechanistic insights into the role of the Mre11 variants inducing genomic instability and cancer and has potential to influence cancer therapeutics.Support or Funding InformationThis research was supported by Murdock College Research Program for Natural Sciences ‐ Life Sciences grant (#201812085) and Linfield College Faculty Student Research Collaborative Grant (FSRCG) to SR
A Conserved Tyrosine Residue of EcSpeG is Absolutely Critical for Enzymatic Activity
Authors: Lim Ee Qi , Le Van , Dang Joseph , Law Melissa , Kuhn Misty L. 
Published: April 2020

The Spermine/Spermidine N‐acetyltransferase from Escherichia coli (EcSpeG) is an allosteric dodecameric enzyme that belongs to the Gcn5‐related N‐acetyltransferase (GNAT) superfamily of enzymes. Under stressful conditions, SpeG acetylates the polyamines spermine (spm) and spermidine (spd), which bind to the active site and allosteric site of the protein. These polyamines are important polycationic molecules for many life processes including cell growth, protein synthesis, and metabolic regulation. GNATs commonly use a general acid base catalytic mechanism to acetylate their substrates and most have a key tyrosine residue that acts as the general acid in the reaction. It was previously shown that mutating this conserved residue in EcSpeG to phenylalanine did not abrogate the catalytic activity. In our experience, mutating this conserved residue in other GNATs has shown it is absolutely critical for activity. Therefore, we created multiple point mutations to test whether the identity of the residue at this position altered catalytic activity. Similar to our previous results with other GNATs, we found this tyrosine residue was critical for activity.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).
High carbohydrate diets increase respiratory quotients above 1 due to lipid synthesis
Authors: Talal Stav , Cease Arianne , Harrison Jon 
Published: April 2020

The respiratory quotient (RQ, carbon dioxide emission/oxygen consumption) is believed to range from 0.7–1 depending on the fuels used for catabolism. However, RQ can rise above 1 when CO2 is released without oxygen consumption. This can occur when hexose sugars are catabolized to pentose sugars via the pentose phosphate pathway to produce NADPH for glutathione regeneration. It is also hypothesized RQs > 1 can occur under lipid synthesis when glucose is catabolized by glycolysis to acetylCOA. However, to our knowledge, no prior studies have assessed animal RQ during periods of carbohydrate conversion to lipid. We used stop‐flow respirometry to measure RQ values for nymphal South American locusts (Schistocerca cancellata) that had been consuming artificial diets varying in carbohydrate:protein ratio for 3–5 days. For locusts measured during the hour after a meal, RQ values increased as the carbohydrate:protein content of the previously‐consumed diet increased, to a maximal value of 1.2. Locusts consuming diets high in carbohydrate:protein ratio synthesized fat at high rates, consistent with the hypothesis that an RQ above 1 is an indicator of synthesis of lipid from carbohydrate.Support or Funding InformationThis research was supported by NSF IOS‐1826848 and BARD FI‐575‐18.
Hypoxia Susceptibility Related to the Expression of Long Noncoding RNA as Regulators of Abraxas2 and Camk2d in the Heart Tissue of a Hypoxic Mouse Model
Authors: Phan Sheshanna , Hassan Omron , Yermian Narineh , Fomicheva Ekaterina , Bondarenko Vladimir 
Published: April 2020

Long noncoding RNAs (lncRNAs) play a regulatory role in hypoxic disease states, and identifying regulators that control gene expression in a hypoxic mouse model will introduce therapeutic targets and biomarkers of susceptibility to hypoxia. Previous studies show that CD‐1 and C57BL/6J mice are sensitive and resistant to hypoxic stress, respectively.CD‐1 and C57BL/6J mice were subjected to an intraperitoneal injection of SE‐175 (0.7 mg/kg) to induce a hypoxic response or 1x phosphate‐buffered saline (PBS) and then sacrificed after five hours in normoxic condition. RNA was extracted from heart tissue and analyzed in a microarray. Genomic BLAST was performed between the human genome and mice lncRNAs with ±2 fold change in expression (p < 0.05). The expression of several genes coding sequences and their associated lncRNAs were analyzed by qPCR.We identified two lncRNA 1500002F19Rik and LOC108168899 that were found in close proximity to the genes Abraxas2 and Camk2d, respectively. Microarray results suggested that 1500002F19Rik and LOC108168899 may play a role in the expression of Abraxas2 and Camk2d, respectively. The expression levels of Abraxas2, Camk2d, and their corresponding lncRNA were analyzed using qPCR. In mice treated with SE‐175, Abraxas2 and 1500002F19Rik were both upregulated in C57BL/6J mice, but neither displayed a significant change in CD‐1 mice. Camk2d and LOC108168899 were both upregulated in C57BL/6J mice, while Camk2d was upregulated in CD‐1 mice, but LOC108168899 showed no significant change.Because of the cytoprotective effects of Abraxas2 against oxidative stress, its upregulation and that of 1500002F19Rik in C57BL/6J mice provides a possible mechanism for their resistance to hypoxic stress. Camk2d is implicated in oxidative stress in cardiomyocytes and was upregulated to a higher magnitude in CD‐1 mice than in C57BL/6J mice, while LOC108168899 only showed increased expression in C57BL/6J mice. This suggests that LOC108168899 can be involved in downregulation of Camk2d that prevents further oxidative stress in C57BL/6J mice, so its lower expression in CD‐1 mice can lead to higher expression of Camk2d which may contribute to susceptibility to hypoxia.Support or Funding InformationThis project was supported by Touro University Nevada research grant.
Obesity Increases Microvascular Contractility in Response to Sympathetic Nerve Stimulation
Authors: Souza Gean Domingos , White Carl 
Published: April 2020

Obesity impairs vasodilation and increases contractility in small mesenteric resistance arterioles. The mesenteric microvasculature is innervated by sympathetic and sensory perivascular nerves; however, it isn’t known if changes in innervation contribute to microvascular dysfunction in obesity. The current aim was to characterize the sympathetic and sensory nerve‐mediated responses of isolated mesenteric arterioles from lean and obese mice. We placed 6‐week‐old mice (C57BL/6) on either low or high‐fat diets for 12 weeks. We then isolated third order mesenteric arterioles and used pressure myography to record the effect of perivascular nerve activation by electrical field stimulation (EFS). EFS (20 V, 3 Hz, 2 ms pulse width) caused vasoconstriction which was attenuated by the voltage‐gated Na+ channel blocker tetrodotoxin (TTX, 1 μM). Vasoconstriction (% maximal constriction) was larger in vessels from obese (50% ± 2) mice compared to those from lean (22 ± 5%) animals (P<0.001, n=3, t‐test). To assess the effect of obesity on sensory innervation, vessels were treated with guanethidine 10 μM to suppress sympathetic nerves, and precontracted with 1 μM phenylephrine. Under these conditions, EFS evoked similar relaxations (% maximal relaxation in zero calcium and sodium nitroprusside) in the lean (36% ± 11) and obese (45% ± 16) groups (P>0.5, n=3, t‐test). In conclusion, these data show that during obesity the contractile response to sympathetic innervation is increased without change in the dilatory response to sensory innervation.Support or Funding InformationThis work was supported by NIH grant HL142906.
Glucose Limiting Conditions Can Lead to Activation of No‐Go Decay and Subsequent P‐body Assembly
Authors: McManus Gretchen , Segal Scott P. 
Published: April 2020

The budding yeast, Saccharomyces cerevisiae preferentially uses glucose as a primary carbon source. When glucose is abundant, it is metabolized anaerobically, leading to the production of ethanol. However, as glucose becomes depleted, yeast will enter diauxic shift. Under this condition, growth will slow, and glucose becomes metabolized aerobically. One effect of the upregulation of aerobic metabolism will be a subsequent increase in the generation of intracellular reactive oxygen species (ROS). The increase of ROS can lead to oxidation of a number of different molecules in the cell, including of nucleic acids. This can lead to the formation of 8‐oxoguanine bases (8‐oxoG). The formation of 8‐oxoG bases in DNA can cause a G to A transition. However, in mRNA the presence of 8‐oxoG will elicit ribosome stalls, resulting in quality control by the No‐Go decay pathway. No‐Go decay is mediated by the proteins Hbs1p and Dom34p, which act to remove stalled ribosomes, and will promote cleavage of the mRNA at the stall site. The remaining 5′ fragment is subject to 3′–5′ decay by the cytoplasmic exosome, while the 3′ fragment is degraded 5′‐3′ by exonuclease Xrn1p in P‐bodies, which are sites of mRNA degradation.Upon growing yeast into diauxic shift, an increase in P‐body assembly was observed. However, stress granules, which act as sites for mRNA storage during physiological stress, failed to assemble. The same result is seen upon directly exposing yeast to conditions in which glucose is limiting (0.5% glucose). This observed increase in P‐body assembly appears to be due to an upregulation of No‐Go Decay. In strains lacking the proteins Dom34p and Hbs1p, P‐body assembly is abrogated as compared to the wild type strains. These data suggest that glucose limiting stress can potentially lead to an increase in ROS, which can damage mRNA leading to activation of No‐Go Decay and subsequent P‐body assembly.
Piezo1 Mechanosensor is Impaired in Pudendal Artery and Corpus Cavernosum of Spontaneously Hypertensive Rats
Authors: Justina Vanessa Dela , Priviero Fernanda , Giachini Fernanda Regina , Webb R Clinton 
Published: April 2020

Erectile dysfunction (ED) is highly associated with risk factors for cardiovascular diseases, including obesity, diabetes and arterial hypertension. The cavernous arteries respond to shear‐stress flow mediated vasodilation and this response is decreased in patients with either neurogenic and vasculogenic ED. Piezo1 channel is a non‐selective stretch‐activated ion channel which has been described to be expressed in the vasculature and it senses shear stress. Piezo1 channel has been shown to induce endothelial nitric oxide synthase activation to induce vasodilation whereas Piezo1 deficiency contributes to the development of arterial remodeling in hypertension. We hypothesize that in physiological conditions, upon sexual stimulation, increased blood flow mediates shear stress activating Piezo1 channels in the pudendal artery and corpus cavernosum, which facilitates relaxation of the arteries and the cavernous smooth muscle. On the other hand, in arterial hypertension the increased pressure causes decreased sensitivity of Piezo1 channel leading to decreased relaxation of the pudendal artery and corpus cavernosum, contributing to the development of erectile dysfunction. Corpus cavernosum and pudendal artery from male Wistar and spontaneously hypertensive rats [SHR (11 month‐old)] were removed, cleaned and mounted in wire myographs. Concentration response‐curves to Yoda1 (chemical agonist for Piezo1 channel) were performed in corpus cavernosum and pudendal artery in the presence or absence of nitric oxide synthase (NOS) inhibitor (L‐NAME, 100 μM, 30 min). Yoda1 causes concentration dependent relaxation in the corpus cavernosum and pudendal artery, which were significantly lower for SHR animals [Emax 14.80 ± 6.47 vs. 37.32 ± 2.10] (corpus cavernosum)] and [Emax 47.34 ± 7.59 vs. 25.52 ± 6.43 (pudendal artery)]. Further, acute NOS inhibition impairs corpus cavernosum relaxation to Yoda 1. In conclusion, thise results are very innovative since the concept that mechansensitive channels are expressed in the cavernous tissue and pudendal artery and may play a role for the erectile function has not been previously investigated. The data provided by this research will help to elucidate additional mechanisms related to ED and could bring new insight about therapeutic targets for the treatment of refractory ED.Support or Funding InformationNIH ‐ HL13604
Metformin Attenuates High Glucose‐Induced Coronary Vascular Endothelial Hyper Permeability Via Inhibition of Orai‐1 Mediated Store‐Operated Calcium Entry
Authors: Ali Shamsideen , Doan Do , Ojong Terrence , Solomon Helawi , Corpuz Ersever , Huynh Thai , Haziq Muhammad , Shahid Mohd , Siddiqui M. Rizwan , Newaz Mohammad , Akhtar Suhail , Ahmad Zulfiqar , Tauseef Mohammad 
Published: April 2020

Increase in vascular endothelial permeability is an earliest pathological hallmark in diabetes mellitus, which progressively leads to cardiovascular disease. Stromal‐interaction molecule 1 (STIM1), upon sensing the depletion of calcium (Ca2+) from the endoplasmic reticulum (ER) store, organizes as a puncta that triggers store‐operated Ca2+ entry (SOCE) via plasmalemmal Ca2+‐selective Orai1 channels in endothelial cells. Thus, signals to disrupt endothelial cell‐cell junctions’ integrity and increase in endothelial permeability. Recent studies show that the anti‐diabetic drug metformin confers vascular benefits beyond glycaemia control and reduced the high risk of cardiovascular events in pre‐diabetes patients. However, the precise pharmacological role of metformin and the mechanism to regulate SOCE‐induced endothelial hyper permeability response in coronary vasculature remain enigmatic in the pathogenesis of hyperglycemia. Here, we demonstrate a previously undetermined role of metformin in inhibiting the Orai1 mediated induction of SOCE and thereby preventing the disintegration of vascular endothelial (VE) cadherin in high‐glucose exposed coronary vascular endothelial cells (ECs). Our data showed that exposing the human coronary endothelial cell monolayer to high glucose media (25mM) for 48 hours increased the expression of Orai1, protracted SOCE and the increased in endothelial permeability. We found that SOCE mediated by Orai1 activated the Pyk2 in ECs. Intriguingly, we observed the tyrosine phosphorylation of vascular endothelial‐protein tyrosine phosphatase (VE‐PTP) at tyrosine (Y) 1981 residue downstream of the Pyk2 activation in high glucose milieu. Our results showed that metformin prevented the SOCE by decreasing the expression of Orai1 and thereby abrogated the Pyk2 mediated phosphorylation of VE‐PTP in high glucose condition. Thus, led to the stabilization and maintenance of VE‐cadherin at interendothelial junctions and strengthening the barrier function. Our data identify heretofore unprecedented signaling mechanism by which metformin via inhibiting SOCE, maintains VE‐cadherin integrity and henceforth decreased high glucose induced hyper permeability response in human coronary endothelial cells.Support or Funding InformationThis work is supported by the Department of Pharmaceutical Sciences, Chicago State University College of Pharmacy (CSU‐COP) research funding to Mohammad Tauseef.