bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessing the Effects of Leptin and Angiotensin II Upon Expression of Agouti‐Related Peptide in the GT1‐7 Cell Model
Authors: Hei Megan Vande , Patil Chetan N. , Sapouckey Sarah A. , Balapattabi Kirthikaa , Oliveira Vanessa , Deng Guorui , Grobe Justin L. 
Published: April 2020

Leptin acts at its receptor (Lepr) within the arcuate nucleus of the hypothalamus (ARC) to reduce feeding behavior and increase resting metabolic rate (RMR) in part through the inhibition of Agouti‐related peptide (Agrp) signaling. Previously we demonstrated that a unique subset of Agrp neurons express the angiotensin II (ANG) type 1a receptor (Agtr1a). Genetic deletion of Agtr1a from Agrp neurons of mice was sufficient to disinhibit expression of Agrp within the ARC, and to attenuate adipose sympathetic nerve activity responses to leptin. In contrast, RMR responses to brain renin‐angiotensin system (RAS) stimulation are intact in the dysfunctional Lepr db/db mouse model, and acute leptin administration does not additively exaggerate RMR activation in a transgenic mouse model of increased brain RAS activity. New unpublished data also indicate that ANG signaling within the ARC stimulates RMR through suppression of Agrp expression and Agrp neuron electrical activity, and thereby disinhibition of melanocortin Mc4r receptor signaling. To further dissect the interaction of Lepr and Agtr1a within Agrp neurons, here we examined the effects of leptin and ANG stimulation of the “GT1‐7” immortalized cell culture model of mouse Agrp‐expressing cells. We confirmed that cultured GT1‐7 cells express critical markers of the Agtr1a‐positive Agrp neuron subtype, including Agrp, Agtr1a, and Neuropeptide‐Y (Npy), but not pro‐opiomelanocortin (Pomc). Dose‐ and time‐course experiments were performed to identify mid‐range doses and time courses for Agrp gene expression responses to acute application of leptin and ANG. Subsequently, Agrp expression responses to low doses of leptin (100 nM) and ANG (100 nM), which would allow detection of any additive or synergistic effect, were assessed after 1 and 2–2.5 hours to evaluate the hypothesis that leptin and ANG signaling are non‐additive for the suppression of Agrp expression. After 1 hour, ANG (0.66 (0.49–0.91), fold of vehicle (± 1 sem), n=0.5) and leptin (0.61 (0.44–0.84), n=6) had similar effects on Agrp mRNA expression compared to vehicle (1.00 (0.86–1.17), n=7), but co‐administration of both peptides had no synergistic effect (0.96 (0.78–1.18), n=5). Likewise after 2–2.5 hours, compared to vehicle (1.00 (0.78–1.28), n=6), ANG (0.56 (0.34–0.94), n=6) and leptin (0.69 (0.57–0.85), n=6) had similar effects that were not additive (0.81 (0.67–0.98), n=6). These findings support the preliminary conclusion that the effects of leptin and ANG upon Agrp expression are not additive in the GT1‐7 cell culture model of Agrp neurons. These findings support our working model in which leptin action at the ARC results in increased Agtr1a signaling to suppress Agrp, ultimately to disinhibit Mc4r signaling and thus increase resting energy expenditure.Support or Funding InformationHL134850, HL084207
The Glucosome: A Metabolic Complex for Glucose Metabolism and Its Functional Contribution to Cellular Metabolism in Living Cells
Authors: An Songon 
Published: April 2020

There have been growing evidence that metabolic enzymes not only compartmentalize in the membrane‐bound organelles, like mitochondria, but also form spatially‐resolved, membraneless granules in the cytoplasm of the cells. Recently, we have demonstrated that all the cytoplasmic, irreversible enzymes in glycolysis and gluconeogenesis (i.e. glucose metabolism) dynamically organizes into a macromolecular metabolic complex, namely the “glucosome,” whose granules form in various sizes in human cells. Our biophysical characterization reveals that the enzymes inside the glucosome granules directly interact with each other while the granules themselves also dynamically undergo fusion and fission in the cytoplasm. Importantly, quantitative high‐content imaging assays support that glucosome granules are metabolically functional to regulate glucose flux between energy metabolism and building block biosynthesis in a size‐dependent manner. Furthermore, our single‐cell analysis reveals that glucosome granules functionally oscillate during the cell cycle in a size‐dependent manner. Collectively, we propose that the enzymes in glucose metabolism reversibly form phase‐separated glucosome granules, which are functionally relevant metabolic complexes for glucose metabolism in human cells.Support or Funding Information• GM125981 (An) and CA219609 (An)
Site‐Specific Opening of the Blood‐Brain Barrier by Extracellular Histones
Authors: Villalba Nuria , Baby Sheon , Yuan Sarah Y. 
Published: April 2020

Increased extracellular histones in the blood are known as a biomarker for vascular dysfunction observed in patients with severe trauma or sepsis. While many previous studies have been focused on histone‐associated coagulopathy and organ (lung, kidney, liver) failure, limited information is available regarding the effects of histones on the brain or cerebral vasculature. Brain endothelial cells and cell‐cell junctions constitute the blood‐brain barrier (BBB) providing a critical paracellular seal that restricts the transfer of harmful substances from the circulation into the brain. It remains unclear whether circulating histones affect BBB structure or permeability function. To address these gaps, we applied a combination of in vitro functional analyses to evaluate the direct effects of histones (10–100 micrograms/mL) on brain microvascular endothelial cells by measuring transendothelial electrical resistance and solute flux. We also used in vivo approaches to obtain evidence of their influence on BBB integrity by quantifying brain tissue accumulation of intravenously injected tracers of different sizes: sodium fluorescein (376 Da), Alexa fluor 555‐cadaverine (1 kDa) and 3 kDa Texas‐Red dextran, in mice receiving a sublethal dose of histones (45 mg/Kg, iv). In mouse brain endothelial cells, treatment with 100 micrograms/mL histones resulted in increased paracellular permeability to sodium fluorescein and reduced barrier resistance, accompanied by discontinuous staining of the tight junction proteins zona ocludens‐1 (ZO‐1) and claudin‐5. The histone effect did not seem to result from cell death or toxicity, as indicated by negative propidium iodide staining. In mice infused with histones, the BBB permeability to small solutes of <1 kDa was increased, whereas tracers larger than 3 kDa remained impermeable across brain microvessels. Further analysis of coronal sections in different brain regions showed that histone‐induced tracer leakage mainly occurred in the hippocampus, but not in the cerebral cortex. Moreover, BBB dysfunction was associated with a reduced expression of several junction proteins in the hippocampal region. Together, these data suggest for the first time that circulating histones cause a region‐specific disruption of the BBB which may be responsible for impaired cognitive function observed in sepsis survivors.Support or Funding InformationThis work is supported by NIH grants: GM097270, HL070752, HL126646 and HL070752 to SYY.
TRAF3IP2 ablation protects against obesity‐associated glycemic dysregulation, elevated blood pressure, and endothelial dysfunction
Authors: Grunewald Zachary Ian , Woodford Makenzie L. , Ramirez-Perez Francisco I. , Morales-Quinones Mariana , Manrique-Acevedo Camila , Siebenlist Ulrich , Martinez-Lemus Luis A. , Bysani Chandrasekar , Padilla Jaume 
Published: April 2020

Obesity and type 2 diabetes (T2D) are leading independent risk factors for cardiovascular disease morbidity and mortality. However, the precise molecular mechanisms underlying the development of cardiometabolic dysfunction in obesity and T2D remain largely elusive. The recently identified cytoplasmic adapter molecule TRAF3 Interacting Protein 2 (TRAF3IP2) is known to regulate various pathological stress pathways, including inflammation and oxidative stress, associated with obesity and T2D. Accordingly, we tested the hypothesis that TRAF3IP2 mediates metabolic and vascular dysfunction associated with chronic high fat/high sucrose (HFHS) feeding. The results show that HFHS feeding for 16 weeks (starting at 5 weeks of age) increased body weight and impaired glucose tolerance in wild‐type (WT) male and female mice relative to control chow‐fed mice (P<0.05). Notably, glucose intolerance was attenuated in HFHS‐fed male and female homozygous TRAF3IP2 knockout (KO) mice (P<0.05) compared to WT counterparts despite greater weight gain. Interestingly, male TRAF3IP2‐KO mice exhibited protection against HFHS feeding‐induced elevations in blood pressure (tail cuff plethysmography) and ex vivo aortic endothelial dysfunction (P<0.05). However, female mice fed HFHS were protected against increases in blood pressure and impairments in aortic endothelial function and, thus, deletion of TRAF3IP2 was inconsequential (P>0.05). In summary, our data show that TRAF3IP2 plays a causal role in obesity‐associated glucose intolerance, elevated blood pressure and endothelial dysfunction. These findings implicate TRAF3IP2 as a promising therapeutic target in cardiometabolic dysfunction associated with obesity.Support or Funding InformationDept. of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, USADalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA Dept. of Biological Engineering, University of Missouri, Columbia, MO, USA Division of Endocrinology and Metabolism, Department of Medicine, University of Missouri, Columbia, MO, USA Harry S. Truman Memorial Veterans’ Hospital, Columbia, MO, USA Laboratory of Immunoregulation, NIAID/NIH, Bethesda, MD, USA Dept. of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA Division of Cardiovascular Medicine, Department of Medicine, University of Missouri, Columbia, MO, USA
The Role of Lifelong Physical Activity on Cardiovascular Function
Authors: Mortensen Stefan , Munch Gregers , Boushel Robert , Calbet José 
Published: April 2020

IntroductionAgeing is associated with vascular dysfunction and a reduced capacity of the central circulation to deliver O2 to the contracting muscles. The purpose of present study was to investigate the role of lifelong physical activity level on vascular function and hemodynamics during whole‐body exercise.MethodsVascular function was determined by femoral arterial Ach infusion (10, 25 and 100 μg/min/kg leg mass) and central (ICG) and limb (thermodilution) hemodynamics were measured during incremental cycling to exhaustion with and without simultaneous arm cycling (50w) were determined in 9 young (Y) (23±1 years; mean±SEM), 9 lifelong sedentary elderly (SE) (66±2 years), 8 lifelong moderately‐active elderly (MAE) (64±2 years) and 8 lifelong very active elderly (VAE) (65±2 years) men. Data was analyzed with one‐way repeated measure ANOVA (within groups) and two‐way ANOVA (between groups).ResultsThe vasodilatory response to ACh was lowest in the SE, higher in MAE and VAE (P <0.05) and highest in the Y (P <0.05). During incremental cycling, peak workload was higher in the VAE (313±10 W) and MAE (274±14 W) compared to Y and SE (247±13; 191±3 W; P<0.05). Leg blood flow (LBF) increased similarly in VAE, MAE and SE, but peak values were higher in VAE, MAE and Y compared to SE (7.8±0.5; 7.9±0.9; 8.6±0.4 vs. 6.4±0.4 L/min; P<0.05). Leg a‐vO2 difference was higher in VAE and MAE compared to the Y and SE at all workloads (P<0.05), whereas leg VO2 was higher in VAE, MAE and Y compared to SE at exhaustion (P<0.05). During combined arm and leg cycling LBF, leg a‐vO2 difference and VO2 was lower in Y and SE compared to leg cycling alone (P<0.05). Mean arterial pressure increased in all groups, but was lower in Y (P<0.05).ConclusionsThese results demonstrate that lifelong moderate physical activity can maintain aerobic power despite a lower vascular function and exercise hyperemia by an increase in O2 extraction.
Impact of Reduced ASIC2a on Cortical Thickness, Microglia Density, and Brain Water Content in E18.5 Fetuses
Authors: Sherrod Akia M. , Shao Qingmei , Thompson Rachael , Griffin Ashley D. , Jones-Muhammad Maria , Warrington Junie Paula 
Published: April 2020

Acid‐sensing Ion Channels (ASICs) are ligand‐gated cation channels that respond to acidic stimuli. ASIC2 is widely expressed in neurons of the central and peripheral nervous system as well as on microglia. Although ASIC2 plays a role in cell migration, their role in brain development is not fully known. We tested the hypothesis that reduction or absence of ASIC2a contributes to changes in microglia density, cortical thickness, and brain water content during development. Brains were collected from ASIC2a wild type (WT, n=6), heterozygous (HET, n=4), and homozygous (HOMO, n=3) fetuses at E18.5. We used hematoxylin & eosin (H&E) staining for cortical thickness measurements, immunofluorescence staining using ionized calcium‐binding adapter molecule (Iba‐1) to measure microglia density, and wet weight to dry weight ratio for brain water content. Reduction of ASIC2a had no impact on cortical thickness (WT=499±21, HET=509±7, and HOMO=478±21 μm; p=0.60) or microglia density in the subventricular zone near the lateral ventricle (WT=22±2, HET=18±2, and HOMO=24±3; p=0.34) at E18.5. Interestingly, microglia morphology in HET fetuses were different compared to WT and HOMO mice with thinner and longer processes. Brain water content increased in HOMO mice (88.2±0.7%) compared to WT (86.5±0.3%, p<0.01) and HET (86.8±0.2%, p=0.02) fetuses. Our results indicate that while reduced ASIC2a does not contribute to changes in microglia density or cortical thickness in E18.5 mouse fetuses, reduced ASIC2a induces morphological changes in microglia and ASIC2 knockout increases brain water content at E18.5. Increased brain water content could be an indicator of hydrocephalus. In ongoing studies, we are determining whether reduced ASIC2a mediates structural and functional impairments in the neurovasculature of the maternal and developing brain.Support or Funding InformationNIH Grants: R00HL129192, R00HL129192‐S1
Vasoreactivity of the Murine External Jugular Vein and Carotid Artery
Authors: Cho Jae Min , Shiu Yan-Ting , Symons J David , Lee Timmy 
Published: April 2020

Few studies have characterized vasoreactivity of the murine external jugular vein. This segment often is used in preclinical models to evaluate vascular remodeling in response to arteriovenous fistula (AVF) maturation. When an AVF is established, the venous segment is exposed to arterial pressures and disturbed flow patterns that have strong potential to impact vasoreactivity. Before testing this hypothesis in the context of AVF, we sought to establish procedures to comprehensively characterize endothelium‐dependent and vascular smooth muscle function of the carotid artery and external jugular vein from healthy mice. External jugular veins and ipsilateral common carotid arteries were isolated from five‐month‐old male C57BL/6 mice and vasomotor responses were evaluated using isometric tension procedures. External jugular veins developed tension (p<0.05) to the voltage‐gated Ca2+ channel opener potassium chloride (KCl) and the thromboxane A2 receptor agonist U‐46619, but not to the α‐1 receptor agonist phenylephrine (PE), whereas common carotid arteries responded to all three vasocontractile agents in a more robust (p<0.05) manner. While maximal responses (~70%) to the endothelium‐dependent vasodilator acetylcholine (ACh) were similar between the venous and arterial segments, the dose required to achieve this value was lower (p<0.05) in the artery versus the vein. Nitric oxide synthase (NOS) inhibition using L‐NMMA attenuated (p<0.05) but did not abolish ACh‐evoked vasorelaxation in both vascular segments. Endothelium‐independent vasorelaxation to sodium nitroprusside (SNP) was similar in the artery and the vein. Endothelium‐dependent and vascular smooth muscle function can be reliably assessed in the murine external jugular vein of healthy male C57Bl/6 mice. Compared to common carotid arteries, external jugular veins are resistant to PE‐evoked vasocontraction, less responsive to KCl and U‐46619‐evoked vasocontraction, less sensitive to ACh‐evoked vasorelaxation, and equally responsive to NOS inhibition and guanylate cyclase activation via SNP. Ongoing studies will determine if and how external jugular vein function is altered by arterial pressures and disturbed flow patterns that are encountered subsequent to establishing an AVF.Support or Funding InformationJMC (University of Utah Graduate Research Fellowship); YTS (R01DK100505; I01BX004133); JDS (AHA16GRNT31050004, NIH RO3AGO52848, RO1HL141540); TL (R44DK109789, R01HL139692, I01BX003387).
An Alternative Method of Expressing Appreciation to Families of Body Donors
Authors: Corson Andrew , Ohara Peter 
Published: April 2020

INTRODUCTIONFor over fifteen years, the UCSF Willed Body Program (WBP) has sponsored an annual student‐led body donor memorial service. The service provides first year UCSF medical, pharmacy, physical therapy and dental students with an opportunity to appreciate and process their experiences in the anatomy lab. Due to a number of limiting factors, including a lack of facilities to host the expected number of attendees, donor families are not currently invited to the service. Donor families have expressed disappointment to WBP staff over not being included. Recognizing the importance of expressing appreciation to donor families, the WBP has sought alternate methods to honor donors and include families in an expression of gratitude. To this end, the WBP prepared a book featuring personal notes and artwork from medical students that is sent to donor families within a few weeks after the death of a donor.METHODSAt the memorial service students are asked to write notes to donors or donor families on 3″ × 5″ cards, a practice now in its seventh year. WBP staff reviews the notes to ensure they are legible, appropriate and contain nothing that will identify the donors. A number of notes are selected, scanned, and formatted using Adobe Photoshop, imported into Adobe Acrobat and then exported as PDF files for printing. The book also includes student artwork and an introduction written by WBP staff explaining the purpose, value and appreciation for the generosity of body donation. The 2019 book contains 24 pages plus the cover. The cost per book is approximately $3.50 and is printed by UCSF Documents and Media. The WBP mails a copy of the book to each donor family or representative upon a donor’s death. Since January 2019, when the WBP began sending the books, the WBP has received dozens of phone calls expressing appreciation for the book, as well as requests for additional copies. Families regularly comment that they understood that body donation was important but that personal reflections from the students emphasize the profound impact of body donation in a much deeper way.CONCLUSIONThe gift of a whole body to medical education and scientific research is a significant act of generosity that deserves recognition. While memorial events that include donor families are ideal, not all universities have the facilities to hold such events. Alternative opportunities to express appreciation and connect students and donor families are available and can be created with minimal resources while remaining deeply meaningful.
BIOMEDICAL ENGINEERING – AN INTEGRATED APPROACH TO PHYSIOLOGY IN HIGH SCHOOL
Authors: Anjur Sowmya 
Published: April 2020

The Illinois Math and Science Academy (IMSA) is a residential school for students of Illinois gifted in Math and Science. Several programs are offered during summers through the Center for Teaching and Learning (CTL), the outreach arm of IMSA, to ignite student curiosity and passion for science and math and foster interest in STEM. An additional benefit of these programs is that they provide participants with hands‐on inquiry driven laboratory experiences. One of the most popular programs offered is the week‐long Physiology and Biomedical Engineering program, which I have taught for the past several years. Stemming from a successful student activity in my Physiology course, the curriculum is designed to enable students to apply physiological concepts to real world applications using engineering techniques. Students are tasked with visualizing the relationships between the structure and function of the cardiovascular system through biomedical engineering ‐ the creation of heart models, which are designed, engineered, and built during the course of the week. This is followed by a discussion of the biophysics of the fluid dynamics of a closed circuit ‐ how pressure, thickness and resistance factor into blood flow. Although only the mechanical system of the heart is modeled due to time constraints, the electrical system is discussed in the context of the heart models built. Students also have the opportunity to model different pathological conditions in their heart models such as atherosclerosis and Crohn’s disease, and explain the biophysical, molecular and biochemical basis of their creations. Through model‐building and testing, students learn how to apply and integrate engineering principles and biophysics to understand the complex workings of the cardiovascular system.Support or Funding InformationCenter for Teaching and Learning, Illinois Math and Science Academy
Pharmacomicrobiomics of Hepatic Drug Processing Genes During Pregnancy
Authors: Han Lyrialle W. , Wang Lu , Shi Yuanyuan , Dempsey Joseph L. , Pershutkina Olesya V. , Dutta Moumita , Bammler Theo K. , Cui Julia Y. , Mao Qingcheng 
Published: April 2020

At present, little is known about how gut microbiome and pregnancy interplay to regulate expression or the activities of drug processing genes (DPGs). The objective of this study was to investigate the effects of gut microbiome on host hepatic DPGs during pregnancy using conventional (CV) and germ‐free (GF) mice. Four groups of C57BL/6 female mice were used: CV non‐pregnant (CVNP, n=6), GF non‐pregnant (GFNP, n=6), CV pregnant (CVP, n=5), and GF pregnant (GFP, n=5) mice. Hepatic transcriptome and proteome for DPGs were profiled using multi‐omics approach. Plasma bile acids and steroid hormone levels were determined using LC‐MS/MS. Cyp activities were measured using hepatic microsome incubations. Overall, RNA‐seq analysis revealed a similar trend of gene regulation by pregnancy, but different magnitudes of change in hepatic DPGs, in CV and GF mice. Of note, the Cyp3a11 mRNA levels were decreased 1.7‐fold and 3.2‐fold by pregnancy in CV and GF mice, respectively. On the contrary, the Cyp3a11 protein abundance was increased 1.2‐fold and 1.6‐fold by pregnancy in CV and GF mice, respectively. The Cyp3a activity was also significantly induced by pregnancy in CV and GF mice; however, the magnitude of induction in CV mice was >5‐fold greater than that in GF mice. Plasma bile acid and steroid hormone levels were significantly impacted by microbiome and pregnancy‐status, respectively, which may contribute to the differential effects of pregnancy in CV and GF mice. This is the first study to demonstrate that the gut microbiome may play a role in altering hepatic drug disposition in pregnancy.Support or Funding InformationThis project was supported by the University of Washington Drug Metabolism, Transport and Pharmacogenomics Research Program (DMTPR)