bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rapamycin does not reproduce the alterations to Caco‐2 transepithelial electrical resistance caused by the knockdown of Raptor
Authors: Kaur Harleen , Moreau Regis 
Published: April 2020

Intestinal homeostasis is achieved through well‐coordinated interactions between the mucus layer, the epithelial layer and the immune cells of the lamina propria. Owing to its proximity with the luminal content, the intestinal epithelium is exposed to insults of chemical, physical or dysbiotic nature. These insults may perturb the epithelium permeability and trigger a localized immune response, which if not controlled may progress to damage the epithelium. Although the mechanistic target of rapamycin complex 1 (mTORC1) is deactivated in differentiated enterocytes, mTORC1 becomes active under repeated insult or injury to the epithelium and participates in epithelial cell repair. However, many aspects of mTORC1 re‐activation remain to be elucidated. To investigate the effects of graded levels of mTORC1 activity on epithelial barrier function, we knocked down (>90% down) mTORC1 signaling‐associated proteins, Raptor and TSC2, to create three Caco‐2 cell lines in which, after full differentiation in Transwell®, mTORC1 activity was either normal (shScramble cells), low (shRaptor cells, mTORC1 activity 50% lower than shScramble cells) or high (shTSC2 cells, mTORC1 activity 80% higher than shScramble cells). When compared with shScramble cells, shRaptor cells had higher abundance of p‐(Thr172)AMPK (+46%, P<0.05), lower abundance of p‐(Ser757)ULK‐1 (−50%, P>0.05), higher autophagic flux (+180%, P<0.05), and lower expression of pore‐forming tight junction protein Claudin‐2 (−65%, P<0.05). In contrast, shTSC2 cells had higher levels of p‐(Ser757)ULK‐1 (+100%, P<0.05) and Claudin‐2 (+250%, P<0.05) compared with shScramble cells. These mTORC1‐related changes were accompanied by significant alteration to the Caco‐2 transepithelial electrical resistance (TEER), which was 180% higher in shRaptor cells vs. shScramble cells, and conversely 60% lower in shTSC2 cells vs. shScramble cells. Although rapamycin suppressed mTORC1 activity in these cells, rapamycin caused a modest 34% (P<0.05) increase of TEER in shScramble cells, suggesting that factors other than mTORC1 ablation were responsible for the high TEER of shRaptor cells. The use of chloroquine (an inhibitor of autophagosome‐lysosome fusion) showed that autophagy alone could not explain the strong electrical resistance of shRaptor cells. We are currently investigating whether TSC2, whose expression increases as Caco‐2 cells differentiate concomitantly with mTORC1 silencing, might regulate paracellular permeability and tight junction assembly in the epithelium.Support or Funding InformationUSDA‐NIFA
Unraveling the metabolic and machinery constraints on protein secretion through a novel systems biology framework
Authors: Lewis Nathan E. 
Published: April 2020

In mammalian cells, metabolism is a core process driving homeostasis, but variations in other cell processes largely define cell type identity and cell‐type specific functions. The profile of secreted and membrane proteins show substantial cell‐type specificity and drive many tissue specific functions. These proteins, encoded by up to 1/3 of mammalian protein‐coding genes, include hormones, membrane proteins, and extracellular enzymes, and these are synthesized and trafficked through the secretory pathway. The pathway complexity, however, obfuscates its impact on the secretion of different proteins. Unraveling its impact on diverse proteins is particularly important since the pathway is implicated in many diseases and harnessed for biopharmaceutical production. Through the use of network reconstruction approaches and protein interaction assays, we have mapped out the core secretory pathway and integrated it with our genome‐scale metabolic models of human, mouse, and Chinese hamster ovary cells. We first deploy graph‐based approaches to evaluate the dependency of protein secretion on diverse human secreted proteins. We then deployed constraint‐based modeling to quantify the bioenergetic demands for the synthesis and secretion of these proteins. Finally, we deployed these models to engineer mammalian cells for enhanced secretion of high‐value biologic drugs. Thus, we present a platform that enables the study and engineering of the mammalian secretory pathway and metabolism for systems biotechnology.Support or Funding InformationNIGMS R35 GM119850 and the Novo Nordisk Foundation Center for Biosustainability NNF10CC1016517
Comparison of Association Between Physical Activity and Resting Metabolic Rate on Korean Young and Middle‐Aged Adults
Authors: HWANG HYEJUNG , Jung Wonsang , Kim Jisu , Park Hun-young , Lim Kiwon 
Published: April 2020

PurposeThe purpose of this study was to investigate the correlation of body composition, RMR, and PA between Korean young and middle‐aged adults.MethodsThe total subjects were fifty‐three [male n=23, female n=30], thirty‐four healthy young adults [male n=18, female n=16] and nineteen middle‐aged adults [male n=5, female n=14]. All participants measured body composition and Resting metabolic rate (RMR) after overnight fasting (≥8h). The investigation of physical activity was using a Korean version of the WHO Global Physical Activity Questionnaire (GPAQ).ResultsBody composition did not present a significant difference between young adults and middle‐aged adults. The whole‐body bone mineral density (BMD) and bone mineral contents (BMC) was significantly lower in middle‐aged adults. Total blood cholesterol (TC) and blood glucose were significantly higher in middle‐aged adults (TC; 195.21 ± 43.34, Glucose; 103.57 ± 12.61 mg/dL). The RMR was significantly lower in middle‐aged adults (1619.57 ± 290.28 kcal/day) than young adults (1894.37 ± 405.00 kcal/day). In the middle‐aged adults physical activity (PA). PA (METs, min, EE) has inverse correlations with fat mass (FM, kg and %), and blood TG level in young adults. The middle‐aged adults indicate that PA has a significant positive correlation with lean body mass (LBM), FM (%), and RMR. Furthermore, PA EE also shows significant interrelatedness with BMC among the middle‐aged adults.ConclusionThese results demonstrate high levels of PA preserve LBM and RMR in middle‐aged adults, furthermore, young adults demanded more PA to induce change in body composition.Support or Funding InformationThis work
is supported by the Ministry of Education of the Republic of Korea and the National Research Foundation of Korea (NRF‐2019S1A5B8099542).
Role of Apontic in ASP Development in Drosophila melanogaster
Authors: Lozano Camila , Srivastava Ajay 
Published: April 2020

The air sac primordium (ASP), found in the Wing Imaginal Disc of Drosophila melanogaster, can be examined as a model for invasive behavior due to the properties it inhibits during development which imitate those necessary for tumor progression. The Janus kinase/signal transduction and activation (JAK‐STAT) signaling pathway plays a considerable role during the development of the ASP and also has its own implications regarding tumor progression and metastasis. The gene apontic (apt), which codes for a protein expressed in the ASP, is known to be a negative regulator of JAK‐STAT. In this study we investigated whether downregulation of the gene apontic had an effect on the invasive behavior of the ASP through the disruption of JAK‐STAT. Using the GAL4/UAS system for targeted gene expression, we were able to knock down apontic and compare ASP development in affected lines vs. control lines. Through the downregulation of apontic, we observed an increased number of under‐developed ASPs. The data presented is able to provide further understanding into the factors that could potentially play a role in the invasive behavior of tumors.Support or Funding InformationDr. Ajay Srivastava, Aref Ranjbar, WKU Biotechnology Center, KBRIN AREA and IDeA Grants funded by a grant from the National Institute of General Medical Sciences of the National Institutes of Health Grant# P20GM103436, Gatton Academy Research Internship Grant (RIG)
Deletion of SIRT1 in the skeletal muscle decreases type IIa oxidative muscle fiber in mice.
Authors: Hosoda Ryusuke , Kuno Atsushi , Asakura Seidai , Horio Yoshiyuki 
Published: April 2020

Background and AimSIRT1 is an NAD+‐dependent protein deacetylase, which exerts cytoprotective effects. We previously reported that resveratrol, an activator of SIRT1, improves exercise tolerance with upregulation oxidative type of muscle fibers in a mouse model of Duchenne muscular dystrophy. SIRT1 deacetylates and activates PGC‐1α, a co‐activator to promote expression of oxidative muscle fibers. The purpose of this study was to examine whether SIRT1 maintains oxidative muscle fibers for exercise capacity in the skeletal muscle using muscle‐specific SIRT1 knockout mice (SIRT1MKO).Methods and ResultsWe first compared the expression level of SIRT1 in several types of skeletal muscles in wild‐type mouse (WT). The SIRT1 protein level was the highest in the soleus muscle (+3.5‐fold), which is mainly made up of oxidative fibers, compared to the other glycolytic muscles such as quadriceps, gastrocnemius, tibial anterior, and extensor digitorum longus muscles. The SIRT1 mRNA level was most abundant also in the soleus. Immunohistological analysis using soleus muscle sections showed that the percentage of type IIa, one of oxidative muscle fibers, was significantly lower in the SIRT1MKO than that in WT (42% vs. 56%) at 26–32 months old. In contrast, the percentage of glycolytic type IIx+IIb muscle fibers was higher in the SIRT1MKO (15%) compared to WT (11%). Treadmill running distance at 30 months old was significantly shorter in SIRT1MKO (78±8 m) than that in WT (592±10 m).ConclusionThese results suggest that deletion of SIRT1 in the skeletal muscle reduces exercise capacity by decreases type IIa oxidative muscle fiber.
Training effects on central and peripheral components of force, in old healthy subjects: the role of central command.
Authors: Venturelli Massimo , Targhetta Gino , Schena Federico 
Published: April 2020

AimThe aim of this study, was to investigate the role of central command (CC), during resistance training in old healthy men. For this purpose, maximal voluntary contraction (MVC), percentage of neuromuscular activation (%VMA) and rest twitch (RT) were determined before and after 4 weeks of quadriceps electro‐stimulation (ES), or voluntary isometric training (VT).Methods12 old (65–70 years) and 12 young male subjects (20–25 years) were recruited for this study. ES was performed by a commercially available electrical stimulator. ES included 15 minutes of isometric‐evoked contractions (6 s contraction/ 11 s of recovery) in the quadriceps, 3 times a week for a total of 12 training sessions. VT was performed after a washout period of 8 weeks, matching the force‐output recorded during the ES.ResultsMVC was minimally increased (+4%) after ES in old subjects, while young subjects showed a larger amelioration (+28%). After ES, %VMA was not changed (+3%) but RT was increased (+16%) in old individuals, while in the young subjects the changes were greater, +17% and +78%, respectively. Both, young and old subjects exhibited after VT significant increases in MVC +16% and +42% respectively. %VMA and RT in old subjects were increased by +8 and +26%, respectively. Similarly, %VMA and RT were increased in young individuals (+9% and +38%).ConclusionsThe results of the current study, suggest that the CC has a primary role to determine improvement of MVC, especially in old subjects. In fact, after the training period, the greater force ameliorations were retrieved in the consequences of VT. These changes were coupled with increases in central (%MVC) and peripheral (RT) components of force. While, the lack of improvements in %VMA after ES in old subjects suggest that the force amelioration was primarily due to peripheral factors.Support or Funding InformationThis project was supported by the Department of Excellence Grant ‐ Molecular and functional basis of successful aging and frailty SAFe (Successful Aging Frailty) ‐
Exploring How Compartment‐specific Changes in NAD Biosynthesis Influence the Response to Endurance Training
Authors: Lakeland Thomas Victor , Samsudeen Azrah , Metcalfe Louise , Govindaraju Hemna , Turner Nigel 
Published: April 2020

Nicotinamide adenine dinucleotide (NAD) plays a vital role in the maintenance of health, and is known to decline with ageing and with metabolic and chronic disease states. Restoration of declining NAD levels—which can be achieved through diet, exercise, and pharmaceutical‐based interventions—has been demonstrated in various organisms to associate with increased longevity and a return to healthy physical function. Our group has previously observed alterations in metabolic processes and in muscle morphology in mice overexpressing the NAD biosynthetic enzyme nicotinamide mononucleotide adenylyl transferase (NMNAT) to target nuclear (NMNAT1) and mitochondrial (NMNAT3) NAD upregulation. In the present investigation, both NMNAT1 and NMNAT3 mice and their respective wildtype littermates were exposed to a six‐week progressive endurance training programme. Endurance capacity, oral glucose tolerance (oGTT), various measures of circulating and tissue lipid and glucose content, and skeletal muscle protein expression were assessed. Despite substantially reduced muscle mass in the NMNAT1Tg/+ group and lower overall performance in the NMNAT3Tg/+ group, the ability to adapt to exercise training was not diminished in either group (improvement above baseline of 147.7 ± 40.1% and 136.6 ± 28.6% for NMNAT1 TG and WT, respectively; and 98.4 ± 36.1% and 72.3 ± 20.5% for NMNAT3 TG and WT, respectively; n = 8–9). Both training and NMNAT1 overexpression were correlated with reduced glucose levels during oGTT, with signs of improved insulin sensitivity evident in the NMNAT1Tg/+ groups; no evidence of improved glucose handling was evident with NMNAT3 overexpression. NMNAT1—but not NMNAT3—overexpression was associated with elevated glycogen storage, with no discernible impact on lipid handling. NMNAT3 overexpression was associated with reduced serum and liver TAG levels in the sedentary but not the trained group. Our results suggest that, despite alterations in glucose and lipid handling, overexpression of NMNAT in the nucleus or the mitochondria does not result in a reduced capacity for adaptation to endurance training. NMNAT overexpression within the nucleus appears to positively impact glucose metabolism; whereas overexpression within the mitochondria appears to alter lipid metabolism in sedentary animals, and these differences diminish with exercise training.Support or Funding InformationNHMRC APP1128351
High Sodium Diet – Role in Renal Sympathodepression
Authors: Rodionova Kristina , Ditting Tilmann , Fahrmeier Franziska , Ott Christian , Schmieder Roland , Schiffer Mario , Amann Kerstin , Veelken Roland Albert 
Published: April 2020

Afferent renal nerve pathways are likely involved in the development of salt sensitive hypertension. We recently reported that intrarenal NaCl elicited a long‐lasting sympatho‐depression via a neuro‐humoral TRPV1 dependent and tachykinin mediated renal afferent nerve pathway. We now wanted to test the hypothesis that high sodium intake impairs this afferent sympatho‐depressory mechanism.Respective groups were put on tap water, 0.9 % saline for drinking or chow containing 8% NaCl. Cultured dorsal root ganglion neurons (DRG Th11‐L2) of rats with renal afferents were investigated in current clamp mode to assess action potential generation during current injection. Rats were equipped with femoral catheters for blood pressure (BP) & heart rate (HR) assessment, drug application, a renal arterial catheter for intrarenal administration (IRA) of NaCl boil (10 % NaCl, 10 μl) or Capsaicin (CAP 3.3, 6.6, 10, 33*10‐7 M, 10 μl) and a bipolar electrode for renal sympathetic nerve activity (RSNA) recordings; eventually an intravenous (iv) bolus of the NK1‐receptor blocker RP67580 (10*10‐3M, 15 μl) was administered. Results are mean±SEM.In neurons from rats on high salt diet, but not on 0.9 % saline or tap water, the relation of tonic highly active neurons to less active neurons shifted towards less active units (62% tonic neurons in a control group vs. 40% on high salt diet and 63% on saline, significant, p<0.05, z‐test, mean +/−SEM). However, cultured renal neurons from rats on 0.9% saline or on high salt diet exhibited increased action potential production upon stimulation (Controls 13,3+/11,03 APs/600ms vs. saline 19,8+/−2,33 APs/600ms vs. high salt diet 22,2+/−4,54 APs/600ms, significant, <0.05, t−test, mean+/−SEM). 10% NaCl boli IRA induced decreases of RSNA from baseline 4.1±0.6 μV*sec to 2.2±0.8 μV*sec (10% NaCl, p<0.05) impaired in rats on 8% NaCl chow. (Suppressed RSNA unmasked in all groups by an i.v. NK1‐inhibitor).In rats on high salt diet highly active tonic neurons with renal afferents in vitro decreased at the expense of less active phasic neurons in spite of tonic neurons producing more action potentials upon stimulation. The sodium inducible long‐lasting sympatho‐depression via a neuro‐humoral tachykinin mediated afferent renal nerve pathway got eventually impaired.
Endothelial Cullin3 Mutation Causes Vascular Dysfunction, Arterial Stiffening and Hypertension
Authors: Wu Jing , Fang Shi , Hu Chunyan , Lu Ko-Ting , Sigmund Curt D. 
Published: April 2020

Mutations in CULLIN3 gene (causing in‐frame deletion of exon 9) cause human hypertension (HT), which is likely to be driven by a combination of renal tubular and vascular mechanisms. We have recently shown that smooth muscle expression of Cul3Δ9 mutant causes vascular dysfunction and HT via augmented RhoA/Rho‐kinase signaling, strongly supporting a vascular role of Cul3 in BP regulation. To test the importance of endothelial Cul3 in vivo, we bred the conditionally activatable Cul3Δ9 mice with tamoxifen‐inducible Tie2‐CREERT2 mice. The resultant mice (E‐Cul3Δ9) developed nocturnal hypertension (Night time peak systolic BP, E‐Cul3Δ9: 138±3 vs Control: 121±4 mmHg, p<0.01) and arterial stiffening (pulse wave velocity, 3.7±0.3 vs 2.7±0.1 m/s, p<0.01). No difference was seen in daytime BP. Nitric oxide synthase (NOS) inhibitor L‐NAME induced smaller increases in nocturnal peak SBP and DBP in E‐Cul3Δ9 mice (15±1 vs 27±3 mmHg, p<0.01), suggesting their NOS activity is low. Of note, E‐Cul3Δ9 mice exhibited impaired endothelial‐dependent relaxation in carotid artery (Max ACh relaxation: 69% vs 84%, p<0.05) and cerebral resistance basilar artery (41% vs 77%, p<0.01). No difference in smooth muscle function was observed. To determine the molecular mechanisms, we isolated primary aortic endothelial cells from mice carrying the inducible Cul3Δ9 construct and induced Cul3Δ9 expression in vitro using adenovirus carrying Cre recombinase gene. Expression of Cul3Δ9 resulted in marked decreases in wild type Cul3 protein, phosphorylated eNOS, and nitric oxide production. Because protein phosphatase 2A (PP2A) is a known Cul3 substrate which dephosphorylates eNOS, we determined whether impaired eNOS activity was attributable to PP2A. Cul3Δ9‐induced impairment of eNOS activity was rescued by a selective PP2A inhibitor Okadaic Acid (4 nM), but not by a Protein Phosphatase 1 inhibitor Tautomycetin (4 nM). These data define a novel regulatory pathway involving Cullin3/PP2A/phospho‐eNOS in the endothelium. Selective endothelial expression of Cul3Δ9 partially phenocopies the hypertension observed in Cul3Δ9 patients, suggesting that mutations in Cullin‐3 cause human hypertension in part through a vascular mechanism characterized by endothelial dysfunction.Support or Funding InformationNIH and AHA
Caloric restriction reverses left ventricular hypertrophy through the regulation of cardiac iron homeostasis in ob/ob mice
Authors: An Hyeong Seok , Roh Gu Seob 
Published: April 2020

Leptin‐deficient mice manifest obesity, insulin resistance, and left ventricular hypertrophy (LVH); however, LVH’s mechanisms are not fully understood. Cardiac iron dysregulation has been recently implicated in cardiomyopathy. Here we investigated the protective effects of caloric restriction on cardiac remodeling in impaired leptin signaling obese mice. RNA‐seq analysis was performed to assess the differential gene expressions in the heart of wild‐type and ob/ob mice. In particular, to investigate the roles of caloric restriction on iron homeostasis‐related gene expressions, 10‐week‐old ob/ob mice were assigned to ad libitum or calorie‐restricted diets for 12 weeks. Male ob/ob mice exhibited LVH, cardiac inflammation, and oxidative stress. Using RNA‐seq analysis, we identified that an iron uptake‐associated gene, transferrin receptor, was upregulated in obese ob/ob mice with LVH. Caloric restriction attenuated myocyte hypertrophy, cardiac inflammation, fibrosis, and oxidative stress in ob/ob mice. Furthermore, we found that caloric restriction reversed iron homeostasis‐related lipocalin 2, divalent metal transporter 1, transferrin receptor, ferritin, ferroportin, and hepcidin expressions in the heart of ob/ob mice. These findings demonstrate that the cardioprotective effects of caloric restriction result from the cellular regulation of iron homeostasis, thereby decreasing oxidative stress, inflammation, and cardiac remodeling. We suggest that decreasing iron‐mediated oxidative stress and inflammation offers new therapeutic approaches for obesity‐induced cardiomyopathy.Support or Funding InformationThis work was supported by a grant of the Basic Science Research Program through the National Research Foundation of Korea (2015R1A5A2008833).