bluuebunny/crossref_metadata_2025_split huggingface dataset:
Feedback Regulation of HMG‐CoA Reductase in Livers of Mice
Authors: Su Shan , Garland Kristina , Jo Youngah , Hwang Seonghwan , Young Gennipher , Fuentes Iris , Schumacher Marc , Elsabrouty Rania , Johnson Brittany , Debose‐Boyd Russell A. 
Published: June 2021

IntroductionHMG‐CoA reductase is a membrane protein of the endoplasmic reticulum (ER) that catalyzes the reduction of HMG‐CoA to mevalonate, a rate‐limiting step in the synthesis of cholesterol and nonsterol isoprenoids. Sterol and nonsterol isoprenoids exert stringent feedback control on HMGCR through multiple mechanisms. This ensures constant synthesis of essential nonsterol isoprenoids, while avoiding toxic overaccumulation of cholesterol. One of these mechanisms involves sterol‐induced ubiquitination of HMGCR, which marks the enzyme for degradation from ER membranes that is augmented by nonsterol isoprenoids. In this study, we examine the contribution of this sterol‐accelerated ubiquitination/degradation to overall regulation of HMGCR in the livers of mice.MethodsForty mice, including 20 wild‐type (WT) and 20 knock‐in (Ki) mice that express ubiquitination‐resistant HMGCR, were fed diets containing only chow, or chow supplemented with 0.1%, 0.3%, or 1% cholesterol. After five days of feeding, livers were harvested for measurements of cholesterol and triglycerides, immunoblot analysis of six proteins, and qRTPCR of 26 genes related to cholesterol, nonsterol isoprenoid, and fatty acid synthesis.ResultsNormalization of mRNA levels to protein levels indicates that HMGCR Ki mouse livers contain a higher level of HMGCR protein despite mRNA downregulation. Protein and gene expression of SREBP‐2 and its target genes, which contribute to cholesterol synthesis, decreased as expected with increased dietary cholesterol. Conversely, protein and gene expression of SREBP‐1 and its target genes increased, likely due to SREBP‐1c predominance toward fatty acid synthesis, which prevents cholesterol accumulation.ConclusionThe increase in HMGCR protein relative to mRNA suggests that significant posttranscriptional regulation exists in the form of impaired degradation. Furthermore, these normalized values indicate that accumulation of protein is primarily due to impaired degradation at lower cholesterol levels (chow, 0.1%); however, at high cholesterol levels (0.3%, 1%), a greater degree of transcriptional control from sterol‐mediated inhibition of SREBP‐2 regulates HMGCR due to negative feedback. This study demonstrates the role of degradative control on inhibition of HMGCR and may assist in reducing HMGCR accumulation during statin therapy.Support or Funding InformationNIH grants HL020948, GM112409, Ruth L. Kirschstein National Research Service Award (NRSA) Short‐Term Institutional Research Training Grant (T‐35)
Pathophysiological and neurobehavioral characteristics of a propionic acid‐mediated autism‐like rat model
Authors: Choi Jeonghyun , Lee Seunghoon , Won Jinyoung , Jin Yunho , Hong Yunkyung , Hur Tai‐Young , Kim Joo‐Heon , Hong Yonggeun 
Published: June 2021

Autism spectrum disorder (ASD) is induced by complex hereditary and environmental factors. However, the mechanisms of ASD development are poorly understood. The purpose of this study was to identify the standard indicators of this condition by comparing clinical, pathophysiological, and neurobehavioral features in an autism‐like animal model. A total of 22 male Sprague‐Dawley (SD) rats were randomly divided into control and 500 mg/kg propionic acid (PPA)‐treated groups. The rats were subjected to behavioral testing, gene expression, and histology were examined to detect pathophysiological and neurobehavioral alterations. Exploratory activity and non‐aggressive behavior were significantly reduced in PPA‐treated rats, whereas we observed enhanced aggressive behavior in terms of adjacent interactions on Day 14 after PPA treatment. To evaluate gene expression after PPA administration, we analyzed tissue from the hippocampus using reverse transcription polymerase chain reaction (RT‐PCR). Glial fibrillary acidic protein (GFAP) was augmented in the PPA‐treated group on Day 14 after ASD induction, whereas octamer‐binding transcription factor 4 (OCT4) expression was significantly decreased in the PPA‐treated group. The histological evaluation revealed significantly reduced granule cells diameter and granule cell layer (GCL) thickness in PPA‐treated rats compared with control rats. We suggest that PPA administration induced abnormal neural cell organization, which may have led to autism‐like neurobehaviors including increased in aggressive behavior, reduced in exploratory activity, and isolative and passive behaviors.Support or Funding InformationFunds: NRF‐2017R1A2A2A01067169, KGM4611714, 2016 Creative Research Program of Inje University, Republic of KoreaThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Pyrrole‐protein adducts, a mechanism‐based biomarker of pyrrolizidine alkaloid induced hepatotoxicity
Authors: Ma Jiang , Li Mi , Ye Yang , Fu Peter P. , Lin Ge 
Published: June 2021

Pyrrolizidine alkaloids (PAs) are among the most hepatotoxic phytotoxins present in about 3% of the flowering plants. Ingestion of PAs causes hepatic sinusoidal obstruction syndrome (HSOS), characterized by primary sinusoidal endothelial cell damage. The hepatic cytochrome P450‐mediated metabolic activation of PAs leading to the formation of pyrrole‐protein adducts has been considered the major pathway in initiating PA‐induced liver injury (PA‐ILI). Our previous studies provided evidence to support that pyrrole‐protein adducts can potentially serve as a biomarker of PA exposure and PA‐ILI. The present study aimed to 1) investigate the correlation between the level of pyrrole‐protein adducts formed from the metabolism of different PAs and their hepatotoxic potency; and 2) characterize the binding specificity, dose‐response, and elimination kinetics of blood pyrrole‐protein adducts in rats. Two PA‐containing herbs Crotalaria sessiliflora (containing senecionine and seneciphylline) and Gynura segetum (containing monocrotaline), and a representative toxic PA (monocrotaline) were used for the study. We observed that there was a good correlation between the level of dose‐dependent hepatotoxicity (determined by the elevation of serum ALT) and the formation of pyrrole‐protein adducts in the liver of rats treated with different PAs. There was also a good correlation between the hepatic and the blood on the level of pyrrole‐protein adduct formation. The results indicated that pyrrole‐protein adducts were formed dose‐dependently in all the monocrotaline‐treated rat blood protein fractions, including hemoglobin (Hb), plasma, albumin, and residual protein fractions, with the highest level of pyrrole‐protein adducts in Hb fraction. The elimination half‐lives of pyrrole‐protein adducts in rat Hb, plasma proteins, albumin, and residual proteins were determined to be 12.08 ± 1.06, 2.81 ± 0.08, 2.54 ± 0.11, and 2.93 ± 0.04 days, respectively. These findings suggest that pyrrole‐Hb adduct is a potential minimal invasive biomarker of PA exposure and PA‐ILI.Support or Funding InformationThe present study is supported by Research Grant Council of Hong Kong (GRF Grant, Project No.: 471013), CUHK One‐off Funding for Joint Lab/Research Collaboration (Project Code: 3132968) and CUHK School of Biomedical Sciences – Seed Fund for Joint Establishments.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Enhanced expression of pro‐renin receptor and proinflammatory cytokines in Npr1 gene disrupted mice
Authors: Periyasamy Ramu , Das Subhankar , Pandey Kailash N. 
Published: June 2021

Atrial and brain natriuretic peptides (ANP and BNP) activate guanylyl cyclase/natriuretic peptide receptor‐a (GC‐A/NPRA), which regulates blood pressure through inhibition of renin‐angiotensin‐aldosterone system (RAAS). The present study was aimed to determine whether targeted‐disruption of Npr1 gene (coding for GC‐A/NPRA) upregulates pro(renin) receptor (P)RR expression and leads to activation of mitogen activated protein kinases (MAPKs) in Npr1 gene‐knockout mice. The results showed that Npr1 gene disruption enhanced renal (pro)renin receptor expression by 3‐fold in 0‐copy (−/−) mice compared with 2‐copy (+/+) control mice, which in turn was associated with increased expression of angiotensin converting enzyme (ACE) and angiotensin receptor type 1 (AT1R) gene by 2‐fold and 3‐fold respectively. To identify the angiotensin II‐ (Ang II) dependent and ‐independent mechanism of (P)RR, ACE inhibitor captopril and AT1R antagonist losartan were administered to Npr1 mice genotypes. Both drugs did not alter the expression of (pro)renin receptor in all Npr1 mice genotypes. In parallel, renal expression of (MAPKs) p‐Erk1/2 and p‐p‐38 were increased by 2.5‐fold and 3‐fold in 0‐copy mice compared with 2‐copy control mice. Treatment with captopril did not alter the expression of p‐Erk1/2 and p‐p38 in Npr1 mice genotypes compared with their untreated mice counterparts. Interestingly, losartan reduced the expression of p‐ERK1/2 and p‐p38 in 1‐copy mice compared with vehicle‐treated control groups. The present findings suggest that disruption of Npr1 gene upregulates (P)RR and activates MAPKs p‐Erk1/2 and p‐p38 in 0‐copy mice, independent of Ang II generation by enhancing pro‐inflammatory cytokines in a gene dose‐dependent manner.Support or Funding InformationNIH/NHLBI: HL57531NIH/NHLBI: HL62147This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Role of Alpha‐1 Adrenergic Vasoconstriction in Regulating Skeletal Muscle Blood Flow during Single Leg Knee Extension Exercise with Advancing Age
Authors: Theisen Jeremy L. , Ratchford Stephen M. , Clifton Heather L. , Bunsawat Kanokwan , Barret‐O'keefe Zachary , Broxterman Ryan M. , Gifford Jayson R. , Hydren Jay , Rossman Matthew J. , Ives Steve J. , Witman Melissa A.H. , Trinity Joel D. , Garten Ryan J. , Morgan David E. , Nelson Ashley D. , Richardson Russel S. , Wray D Walter 
Published: June 2021

Dynamic exercise evokes an increase in sympathetic nervous system (SNS) activity, a response that contributes to the “fine‐tuning” of blood flow to meet the metabolic demands of active skeletal muscle. Expression of this exercise‐induced increase in SNS activity is blunted within the vasculature of exercising muscle, an event known as “functional sympatholysis”. However, how this process may be altered with advancing age remains unclear. Therefore, the purpose of this study was to determine the role of alpha‐1 adrenergic vasoconstriction in the regulation of exercising skeletal muscle blood flow and the modulating effect of age. Eleven young (6 male, 27±1 yrs) and six older (6 male, 60±4 yrs) healthy volunteers participated in this study. Leg blood flow (LBF; ultrasound Doppler), mean arterial blood pressure (MAP), and leg vascular conductance (LVC) were evaluated at rest and during dynamic single‐leg knee‐extension exercise (0, 5, 10 and 15 W) before and after blood flow‐adjusted intra‐arterial administration of the alpha‐1 adrenergic agonist phenylephrine (PE, 0.03 ug·ml−1). At rest, there was no difference between young and older subjects in the PE‐induced decrease in LBF (−37±4% vs. −31±3%, young vs. older) or LVC (−53±6% vs. −48±2%, young vs. older). During exercise, the PE‐induced decrease in LBF was attenuated in an intensity‐dependent manner, but was not different between young (0W: −20±4%; 5W: −16±3%; 10W: −14±4%; 15W: −5±3%) and older (0W: −15±4%; 5W: −9±4%; 10W: −10±2%; 15W: −5±4%) subjects. Similarly, the PE‐induced decrease in LVC was attenuated as work rate increased, but was not different between groups at any work rate. MAP increased with exercise, but did not differ between groups or as a result of drug administration. Alpha‐1 adrenergic vasoconstriction was similar between young and older adults at rest and during low to moderate intensity knee‐extension exercise, suggesting that functional sympatholysis is not altered with advancing age.Support or Funding InformationThis project is funded in part by the National Institutes of Health (HL118313) and the U.S. Department of Veterans Affairs (RX001697, RX001418, E6910R).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Morphological Changes to the Cruciate Ligaments and Menisci in Relation to ageing.
Authors: Hirtler Lena , Toader Ian‐Philip , Röhrich Sebastian , Kainberger Franz 
Published: June 2021

In this retrospective, cross‐sectional MRI based study on the anatomy of the cruciate ligaments (ACL, PCL) and the menisci (MM, LM) of the human knee, the goal was to identify possible age‐ and gender dependent variations in morphometry of these structures.332 patients were included, 184 women (55,4 %) and 148 men (44,6 %), all who underwent an MRI examination of the knee. Age distribution ranged from 1 year (y) to 78 y with a mean of 33 years. All patients were subdivided in 6 age groups (younger then 10y, 11–20y, 21–30y, 31–45y, 45–55y, older then 56y). Exclusion criteria consisted of poor image quality as well as destructive and space occupying, pathological processes in close vicinity to the capsular apparatus and investigated structures, respectively.Measurements included following parameters. ACL: length, blumensaat angle, ACL‐tibia angle, cross‐sectional‐area (CSA), diameter (APD), width, intercondylar notch width (ICN); PCL: length, PCL angle, Angle Ratio, CSA, APD, width; Menisci: height of the anterior and posterior horns, height and width of the mid‐body, axial APD of the menisci, tibia width.There were significant correlations between age and length, CSA, APD, width and both angles of the cruciate ligaments. Male ACL size was greater in nearly every parameter when compared to the female population. Merely Blumensaat and tibia angle showed greater values in the female cohort. ACL/ICN‐ratio also correlated significantly with age. Especially when evaluating the younger age groups significant differences could be observed. Sagittal height of the meniscus horns correlated significantly with coronal height of the meniscus body in several age groups. There was also a significant correlation between medial and lateral meniscus height. Tibia width presented a significant but weak predictor of medial and lateral meniscus width. This is one of the largest studies evaluating the cruciate ligaments and menisci in different phases of life when considering cohort size. The results concur with most of the results stated in previous and similar studies.Although there has been an abundance in studies about the cruciate ligaments and the menisci in the last decades there is still little detail known about the morphological changes of these structures in different phases of life. The results of this study aim to increase the anatomical knowledge of the investigated structures as well as to establish standard measurements for further studies and to differentiate between normal and pathologic conditions.Support or Funding InformationNo funding was received.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The LexA‐regulated gene ybfE plays a role in DNA metabolism in E. coli
Authors: Hotchkiss Amy Blondin , Kramer Caitlin , Beuning Penny 
Published: June 2021

DNA is constantly exposed to damage‐causing agents. The SOS DNA damage response in Escherichia coli is regulated by the LexA protein, and controls the expression of more than 50 different genes. One of the many genes regulated by the SOS response encodes the uncharacterized protein YbfE. Previous work in our lab has shown ybfE is essential to cell survival after exposure to alkylating agents. In order to characterize ybfE further, two open reading frames are being examined because two different in vitro transcription start sites have been proposed. One open reading frame encodes an additional 23 amino acids at the N‐terminus of the protein and has been shown to cause a striking decrease in cell survival upon overexpression. To Identify genetic interactions, a series of knockout strains have been investigated to determine whether deletion of any one gene alleviates the lethality associated with overexpression of ybfE. To date assays in strains harboring deletions of various DNA repair proteins have not suppressed the lethal overexpression phenotype. In addition, hydroxyurea sensitivity studies are being conducted. Hydroxyurea is known to inhibit DNA replication without inducing DNA damage, allowing further investigation into the role ybfE plays in the SOS response. Deletion of the ybfE gene reduces the susceptibility of wild‐type E. coli to HU suggesting a role for YbfE in DNA metabolism. Further investigation into protein interactions and the role of YbfE in the SOS response are ongoing.Support or Funding InformationSupport from NSF‐MCB‐1615946 and American Cancer Society RSG‐12‐161‐01‐DMC.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Regulation of RNA Polymerase III Transcription Factors BRF1 and BRF2 by Cancer Stem Cell Signaling Pathways
Authors: Cabarcas‐Petroski Stephanie M. , Schramm Laura 
Published: June 2021

The direct link between deregulation of RNA polymerase III (pol III) transcription and the progression and maintenance of cancer cells is well‐established. The small untranslated RNAs which are produced as a result of RNA pol III transcription, including U6 snRNA and tRNAs, play a role in the proliferative capacity of a cancer cell. The requirement of TFIIIB for proper RNA pol III transcription has led researchers to investigate the role of TFIIIB subunits in cancer development. To date, there is evidence demonstrating that the TFIIIB factors, BRF1 and BRF2, play a significant role in cancer development including the classification of BRF2 as an oncogene. Using genomic analysis, we investigated potential factors contributing to deregulation of BRF1 and BRF2. We performed a search for putative transcription factor binding sites within the BRF1 and BRF2 promoters. Specifically, we sought to determine if there were binding sites for transcription factors that have been shown to play a role in the maintenance of cancer stem cells (CSCs). CSCs represent a subpopulation of cells that are responsible for tumor initiation, formation, maintenance and metastasis. CSC specific signaling pathways identified to date include: JAK/STAT, Hedgehog, Wnt, Notch, PI3K/PTEN and NF‐kB. Our search identified CSC related binding sites within the BRF1 and BRF2 promoters that could establish a link between CSC signaling pathways and RNA pol III deregulation. Additionally, utilizing additional genomic analysis from previously published datasets, we correlated BRF1 and BRF2 expression in isolated CSC's. Taken together, these data demonstrate a potential link for BRF1 and BRF2 regulation by CSC associated signaling molecules which could contribute to deregulation of RNA pol III transcription.Support or Funding InformationSandra E. Gleason Faculty Enhancement AwardThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Isoforms of human CD46 Produced by Alternative Splicing Adopt Different Quaternary Structures
Authors: Wu Eugene Y. , Romanoff Emily L. , Woon Jesse W. 
Published: June 2021

Alternative splicing can produce multiple mRNA transcripts from a single gene sequence, thereby expanding the number of protein sequences encoded by the genome of a cell. Protein isoforms from alternative splicing may have different functions owing to their different sequences, but examples of alternative splicing producing isoforms with different structures are lacking. CD46 (membrane cofactor protein) is a cell surface glycoprotein that helps protect human cells from destruction by the complement system and a receptor for several human pathogens. It is alternatively spliced into two main isoforms in the extracellular region (BC and C) that differ by the presence or absence of 15 amino acids. Based on existing structural data, we hypothesized that the C isoforms of CD46 form oligomers while the BC isoforms exist as monomers on the cell surface. Proteins on the HeLa cervical cell surface were treated using a membrane‐impermeable crosslinker, then subjected to denaturing gel electrophoresis and western blotting. HeLa cells express both BC and C isoforms of CD46, but only the C isoform changed its electrophoretic mobility to a higher molecular weight after crosslinking. A549 lung epithelial cells express only the BC isoforms, and the molecular weights of their CD46 proteins were unaffected by the crosslinker. These results indicate that CD46 can exist as monomeric and oligomeric spliceoforms. We show that alternative splicing can produce proteins with different quaternary structures from the same gene.Support or Funding InformationFunded by University of Richmond School of Arts & SciencesThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Evaluation of pro‐pol Frameshifting Efficiencies for Naturally Occurring Variants of HTLV‐1
Authors: White Emily A. , Mouzakis Kathryn , Williams Marcus , Nash Hannah , Hamilton Adam , Harrison Jacob , Eades Austin , Daily Leandrew , Contreras Uriah , Cooper‐Sansone Andrew , Chadeayne Devon , Banks Terrance , Abrams Tara , Joe Natalie , Mylroie Elena 
Published: June 2021

Human T‐cell leukemia Virus Type 1 (HTLV‐1) utilizes two ‐1 programmed ribosomal frameshifts (PRFs) to translate its enzymatic proteins. This translational mechanism induces a change in the ribosomal reading frame during elongation, which allows for the production of proteins from alternate reading frames within a single transcript. Frameshifting is utilized by many retroviruses and is often required for successful replication. Each frameshift site includes three components: a heptad “slippery sequence”, a spacer, and a downstream structure. Preliminary data from our group suggests that the HTLV‐1 pro‐pol frameshift site structure is a pseudoknot. Interestingly, multiple HTLV‐1 isolates include point‐mutations within this pseudoknot structure. How these mutations affect the ‐1 PRF efficiency is uncertain. Here, we investigate the impact of several pseudoknot point‐mutations on the HTLV‐1 pro‐pol frameshift efficiency. Site‐directed mutagenesis was used to insert these mutations into a dual‐luciferase vector that includes the HTLV‐1 pro‐pol frameshift site. The mutated DNA for each variant was transcribed, translated, and used in a dual‐luciferase assay, allowing calculation of the in‐vitro ‐1 PRF efficiencies for each mutant. Our preliminary data suggests that these point‐mutations create significant differences in the ‐1 PRF efficiency.Support or Funding InformationNIH NIGMS SCORE SC2 Award (Award# 1SC2GM121197‐01) and Research Corporation for Science Advancement Cottrell Scholar Award (Award #23983)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.