bluuebunny/crossref_metadata_2025_split huggingface dataset:
Single Amino Acid Mutations in the Na+/Taurocholate Cotransporting Polypeptide (NTCP) Result in Substrate‐Dependent Effects
Authors: Ruggiero Melissa , Malhotra Shipra , Karanicolas John , Swint‐Kruse Liskin , Hagenbuch Bruno 
Published: June 2021

Nonsynonymous polymorphisms can significantly impact the function of a protein. However, so far, the outcome of such mutations at non‐conserved positions are difficult to predict. Previous work showed that some non‐conserved positions have an unexpected outcome when they are mutated: if multiple amino acids are substituted, the results show progressive alterations like a “rheostat”, rather than an “all‐or‐nothing” effect often seen for mutations at conserved positions (“toggle”). To begin to define rules for predicting mutation outcomes at rheostat positions, we used the Na+/Taurocholate Cotransporting Polypeptide (NTCP) as a model transmembrane transporter. NTCP is a sodium dependent bile acid transporter expressed at the basolateral membrane of human hepatocytes. NTCP is important for the enterohepatic circulation of bile acids and also mediates the transport of steroid hormones like estrone‐3‐sulfate (E3S) or drugs like rosuvastatin. We initially focused on the S267F polymorphism that decreased taurocholate transport, stimulated rosuvastatin uptake, and showed no effect on E3S transport. We replaced the serine with all other nineteen amino acids by site directed mutagenesis, transfected the cDNAs into human embryonic kidney cells (HEK293), and determined the uptake of tritiated substrates. In addition, we identified the conserved G102 and the non‐conserved Y146 positions using multiple sequences alignments and homology modeling based on the structures of two bacterial homologues. Both positions fall in mobile regions of NTCP. Interestingly, mutations at S267 resulted in a clear rheostat behavior for taurocholate uptake, with S267F showing only 15% of the function of wild‐type NTCP. Similarly, rheostat behavior was observed for E3S and rosuvastatin, but several mutants transported these substrates 2‐ to 10‐fold higher than wild‐type NTCP, demonstrating that the different amino acid replacements resulted in substrate‐dependent effects. As expected, the non‐conserved Y146 demonstrated rheostat behavior for all three substrates. However, the conserved G102 turned out to be a rheostat position for taurocholate transport but a toggle for the uptake of E3S and rosuvastatin. In summary, we have determined that rheostat positions exist in human NTCP. Furthermore, the functional consequences of single amino acid mutations at the three positions studied so far, varied depending on the substrate tested. Therefore, functional predictions of amino acid mutations seem to be more challenging and will require further experiments at additional positions to potentially define a unifying set of rules.Support or Funding InformationNIH R01 GM077336, P30 GM118247, W.M. Keck FoundationThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Endoglin targeting inhibits tumor angiogenesis in non‐small cell lung cancer
Authors: Chen Chiao‐Yun , Sheu Ming‐Jyh 
Published: June 2021

Endoglin, a transforming growth factor‐β co‐receptor, is highly expressed on angiogenic endothelial cells in many different solid tumors, including lung cancer. In patient samples, increased endoglin expression after the anti‐VEGF treatment was found. In contrast, in vitro TRC105, an endoglin‐neutralizing antibody, increased VEGF signaling in endothelial cells. This suggest that co‐administration with both endoglin antagonist and anti‐VEGF treatment may increase and sustain anti‐angiogenesis status. Subsequently, targeting endoglin is currently undertaken in clinical trials for anti‐angiogenic therapy. We aimed to explore how aspidin‐BB affected the endoglin expression and then effects on angiogenesis in lung cancer cells. Aspidin BB, a phloroglucinol derivative from Dryopteris fragrans (L.) Schott has been reported to demonstrate anticancer activity. In the present study, we investigated how aspidin‐BB affected the endoglin expression and then effects on angiogenesis. The binding mode of aspidin‐BB within the active site of endoglin was analyzed using DS 4.5. Our results showed that aspidin‐BB has strong affinity to endoglin. The results gave us a hint that aspidin‐BB could bind with endoglin and affected the BMP‐9, the main endoglin ligand, induced Alk1/Smad1 and/or Alk5/Smad2 phosphorylation in human umbilical vein endothelial cells (HUVECs). Further study will be focused on co‐administration with both endoglin antagonist and anti‐VEGF treatment, and determine its possibility to increase and sustain anti‐angiogenesis status.Support or Funding InformationThis work was supported by Grants from Ministry of Science and Technology (MOST 103‐2320‐B‐039‐026; MOST104‐2320‐B‐039‐007) and China Medical University (CMU105‐ASIA‐19;CMU106‐ASIA‐14).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Blood Pressure Predicts Endothelial Function and Effect of Ethinyl Estradiol in Young Obese and Lean Women
Authors: Adler Tessa E. , Usselman Charlotte W. , Takamata Akira , Stachenfeld Nina S. 
Published: June 2021

Obesity, mild hypertension and endothelial function are all predictors of cardiovascular disease in women, and we propose that these factors are interrelated. We hypothesized that obesity and high blood pressure are associated with endothelial dysfunction in young women. Further, we hypothesized that short‐term low‐dose ethinyl estradiol treatment would mitigate this dysfunction. We examined hyperemic responses before and during 30 μg/day oral ethinyl estradiol (EE) treatment for 7 days in 16 healthy women (mean 26 ± 5, 19–35 yrs) with normal (NBP; n=7, MAP range: 78–91 mmHg) or mildly elevated blood pressure (HBP; n=9, MAP range: 95–113 mmHg). We evaluated brachial vasodilatory responses following two stimuli designed to elicit different levels of shear stress: 5‐min occlusion (RH‐FMD), and 3‐min occlusion with ischemic handgrip exercise (IE‐FMD). Body composition did not impact RH‐FMD or IE‐FMD responses. In contrast, Pre‐EE, HBP had lower IE‐FMD responses relative to NBP (8.0 ± 3.5% vs. 12.3 ± 3.2%, respectively; P=0.05). During EE, IE‐FMD increased in HBP (12.8 ± 6.1%; P=0.02) and decreased in NBP (5.6 ± 2.4%, P<0.01). The increase in shear stress (8659 ± 4964 vs. 14753 ± 8189 AUC, s−1; P=0.04) contributed to the increase in IE‐FMD in HBP subjects during EE, while shear stress did not change with EE in NBP (9740 ± 3222 vs. 10564 ± 2984 AUC, s−1; P=0.76). MAP did not predict RH‐FMD responses or associated shear stress, pre‐or during‐EE. Thus, 1) in young healthy women, moderately elevated blood pressure was a predictor of endothelial function whereas obesity was not; 2) EE mitigated endothelial dysfunction associated with elevated blood pressure; 3) the enhanced shear stress stimulus was able to subtle differences in endothelial function where the standard FMD stimulus did not. Because HBP women had only mildly high blood pressure, these data are of particular significance given the new American Heart Association guidelines for hypertension.Support or Funding InformationSupported by the APS Undergraduate Research Excellence Fellowship; the Paul Titus Fellowship Fund, Dept. Obstetrics Gynecology and Reproductive Sciences, Yale School of Medicine; and the AHA Postdoctoral Fellowship.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 Effects of a High‐Volume and High‐Intensity Resistance Training Program on Arterial Stiffness
Authors: Pellinger Thomas , Werner Tim , Boutagy Nabil 
Published: June 2021

Arterial stiffness has long been regarded as an indicator of disease and is an independent predictor of cardiovascular events. Controversies exist amongst the impact of resistance training protocols on the stiffening process in the major elastic arteries. This study was designed to address some of the controversies.PURPOSETo determine the vascular impact of a high‐volume (HV), moderate resistance training program and a high‐intensity (HI), moderate repetition training program on arterial compliance.METHODS21 otherwise healthy, male university students with limited resistance training experience (< 6 months) were randomized into one of three groups: 7 control (CO) group (22±3 yrs), 6 HI resistance exercise group (23±3 yrs), and 8 HV resistance exercise group (21±3 yrs). All were subjected to a series of tests including anthropometry, ultrasonography of the carotid artery, applanation tonometry, blood pressure acquisition, and maximal strength assessment. Subjects were instructed to maintain normal dietary patterns throughout the study period. Food consumption was monitored. All subjects in the training groups performed the same 8–10 exercises on training days. Subjects in the HV group trained at 50–70% of 1‐RM with 10–15 repetitions and 2–4 sets per exercise for 3–5 days a week for 12 weeks. Subjects in the HI group trained at 70–95% of 1‐RM with 3–6 repetitions and 2–3 sets per exercise for 3–5 days a week for 12 weeks. Subjects randomized to the control group were instructed to refrain from both cardiovascular and resistance exercise during the study period. Arterial stiffness comparisons were calculated with two‐way ANOVA with repeated measures.RESULTS1‐RM significantly increased for squat (52% vs. 25%, p<0.05), bench press (31% vs. 27%, p<0.05) and seated rows (22% vs. 13%, p<0.05) in the HV and HI groups respectively. Carotid femoral PWV did not change in the HI (7.6±2 vs. 8.1±2 m/s, p>0.05), HV (6.3±1 vs. 6.8±2 m/s, p>0.05), and CO (6.7±1 vs. 6.7±1 m/s, p>0.05) groups. Beta stiffness index did not change in the HI (5.9±3.5 vs. 5.7±2.6 U, p>0.05), HV (6.5±1.9 vs. 6.5±2.1 U, p>0.05), and CO (7.2±4.4 vs. 6.4±3.1 m/s, p>0.05) groups.CONCLUSION12 weeks of HI and HV training does not appear to augment indices for arterial stiffness in young, adult males.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Internal Carotid Blood Flow Responses To The Diving Response In Humans
Authors: Alsalahi Sultan E. , Fisher James P. 
Published: June 2021

The immersion of the face in cold water evokes a powerful autonomic reflex known as the diving response. It is activated primarily by stimulation of the trigeminal nerve (TGS) that innervates the areas around the forehead and cheeks, but its physiological effects are also modulated by secondary mechanisms such as apnoea. The diving response is believed to act to preserve oxygen delivery to the heart and brain. We sought to determine the relative importance of the TGS and apnoea components of the diving response to the regulation of cerebral blood flow.In 8 young, healthy volunteers (aged 24 ± 3 yr; 2 women), middle cerebral artery velocity (MCAV; transcranial Doppler), arterial blood pressure (Finometer), heart rate (ECG) and the partial pressure of end‐tidal carbon dioxide (PETCO2) were recorded. In addition, internal carotid artery diameter and velocity were measured (ICAV) using duplex Doppler ultrasound, and internal carotid artery flow (ICAQ) calculated. Cerebral vascular conductance (CVC) was calculated as; MCAV or ICAQ/MAP. TGS was evoked by the placement of ice packs on the forehead and cheeks under two conditions; 1) while performing an end‐expiratory breath‐hold (+BH), and 2) while breathing spontaneously (‐BH). The second condition was always undertaken last and its duration was matched to that of the first condition. Data were averaged at baseline (3 min) and at the end of each manoeuvre (last 10 cardiac cycles) and are presented as mean ± SEM.The apnoea was held for 26 ± 3 s. During combined TGS+BH, mean blood pressure (88 ± 5 vs. 101 ± 4 mmHg), MCAV (67 ± 9 vs. 82 ± 8 cm s−1) and ICAQ (309 ± 42 vs. 386 ± 56 ml min−1) were increased (p<0.05), while MCACVC (0.77 ± 0.11 vs 0.81± 0.08 cm s−1/mmHg) and ICACVC (3.49 ± 0.47 vs. 3.84 ± 0.60 ml min−1/mmHg) remained unchanged (P<0.05), and heart rate tended to decline (71 ± 2 vs. 65 ± 3 bpm; P=0.072). In contrast, during TGS–BH, mean blood pressure increased (87 ± 2 vs. 91 ± 2 mmHg: P<0.01), while MCAV (65 ± 7 vs. 66 ± 7 cm s−1), MCACVC (0.75 ± 0.08 vs. 0.73 ± 0.08 cm s−1/mmHg), ICAQ (304 ± 40 vs. 296 ± 41 ml min−1), ICACVC (3.38 ± 0.48 vs. 3.17 ± 0.47 ml min−1/mmHg) and heart rate (67 ± 4 vs. 66 ± 4 bpm) remained unchanged (P>0.05).In summary, cerebral blood flow increased when TGS was coupled with an apnoea, but the independent activation of TGS did not elicit an increase in cerebral blood flow. These findings suggest that physiological factors associated with breath holding (e.g., pressor response, CO2 accumulation) make the predominate contribution to diving response mediated‐increases in cerebral blood flow in humans.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Inflammatory Cytokines and Biomarkers in Aging Type 2 Diabetic Rats
Authors: Huo Henry , Harrison Michelle L. , Grotle Ann‐Katrin , Graham James , Stanhope Kimber L. , Havel Peter J. , Stone Audrey J. 
Published: June 2021

Aging, type 2 diabetes mellitus (T2DM), and cardiovascular disease are all associated with systematic low grade inflammation. Accordingly, these conditions alter circulating concentrations of cytokines involved in inflammation and vascular function. Recent studies suggest that these same cytokines may contribute to the sensitization of group III and IV afferents, which are involved in evoking the exercise pressor reflex during skeletal muscle contraction. The purpose of this study was to determine the concentrations of cytokines involved in inflammation and vascular function in aging T2DM rats. To accomplish this we analyzed blood samples drawn from UC Davis T2DM rats at 4 months (BW: 549 ±29 g, glucose: 337±147 mg/dl, HbA1c: 7.4±0.6%, insulin: 5129±3799 pg/ml), 8 months (BW: 546±77 g, glucose: 549±46 mg/dl, insulin: 288±416 pg/ml), and 12 months (BW: 512±144 g, glucose: 551±57 mg/dl, HbA1c: 11.9±2.4%, insulin: 436±167 pg/ml) of age. We used healthy, adult (CTL) Sprague Dawley rats (BW: 465±18 g, glucose: 200±14 mg/dl, HbA1c: 4.7±0.1%, insulin: 1692±1422 pg/ml) as controls. We analyzed serum samples, to determine the concentration of circulating IL‐1β, IL‐10, IL‐4, and insulin, using rat cytokine/chemokine and adipokine multiplex kits (EMD Millipore)and a Bio‐Plex 200 instrument. We found that the concentration of the pro‐inflammatory cytokine IL‐1β gradually, although not significantly, increased in T2DM rats as they aged compared to CTL rats (4 mo: 49±18 pg/ml, n=4; 8 mo: 72±48 pg/ml, n=9; 12 mo: 71±24 pg/ml, n=6; CTL: 38±12 pg/ml, n=6). The concentration of the anti‐inflammatory cytokine IL‐10 decreased in T2DM rats as they aged compared to CTL (4 mo: 542±454 pg/ml, n=4; 8 mo: 112±168 pg/ml, n=8; 12 mo: 467±264 pg/ml, n=6; CTL: 1289±527 pg/ml, n=4; p<0.05). The concentration of the anti‐inflammatory cytokine IL‐4 appears to be more variable over time in T2DM rats as it decreased at 4 mo and 8 mo of age and then increased at 12 mo of age (4 mo: 18±15 pg/ml, n=4; 8 mo: 8±12 pg/ml, n=8; 12 mo: 49±7 pg/ml, n=5; CTL: 25±21 pg/ml, n=6; p<0.05). These results suggest that circulating concentrations of pro‐inflammatory and anti‐inflammatory cytokines are altered in aging T2DM rats and they may be increased or decreased depending on duration of the disease. Additionally, these changes in inflammatory cytokines may play a role in exaggerating the exercise pressor reflex in aging T2DM rats.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
A Role for Hypoxia‐inducible Factor 1‐alpha (HIF1a) Signaling in Suppressing Synaptic Plasticity and Spatial Memory During Intermittent Hypoxia
Authors: Nwakudu Chinwendu U. , Barnard Jasmine , Khuu Maggie A. , Garcia Alfredo J. 
Published: June 2021

Although HIF1a signaling is commonly identified as a mediator of positive homeostatic responses to hypoxia, during intermittent hypoxia (IH), a primary effect of sleep apnea, HIF1a signaling can cause oxidative stress in the body. IH‐dependent oxidative stress can lead to pathophysiological changes throughout the nervous system associated with sleep apnea. The objective of this study is to determine whether HIF1a signaling during IH opposes or facilitates IH‐dependent suppression in synaptic plasticity and spatial memory. Both adult wildtype mice (WT) and mice heterozygous for HIF1a (HIF1a+/−) were either unexposed (control) or exposed to chronic intermittent hypoxia (CIH) for 10 days. Hippocampal brain slices (350 microns thick) were prepared from mice of each group. Extracellular recordings of the field excitatory postsynaptic potential (fEPSP) were made before and after the induction of long‐term potentiation (LTP) in area CA1. While LTP occurred in brain slices of WT from both groups, the magnitude of LTP was larger in the control group (164±6% of baseline, n=5) as compared to the CIH group (115±10% of baseline, n=5). LTP in the brain slices from the HIF1a+/− exposed to CIH was 152±10% of baseline (n=5), which was greater in magnitude compared to WT LTP in the CIH group. Ongoing experiments suggest spatial memory in the Barnes Maze is unaffected by CIH in HIF1a+/−. These findings show that IH‐dependent HIF1a signaling disrupts hippocampal synaptic plasticity and spatial memory, which may contribute to cognitive impairment associated with sleep apnea.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Exercise training protects against aging‐induced cognitive dysfunction via activation of hippocampal PGC‐1α/FNDC5/BDNF pathway
Authors: Belviranli Muaz , Okudan Nilsel 
Published: June 2021

Aging process is associated with decreases in cognitive functions, but this decrease may be reversed by regular exercise. However, the molecular mechanisms responsible from this processes remains unclear. Here, we aimed to investigate the impacts of exercise training on cognitive performances such as locomotion, anxiety‐related behavior, learning and memory and hippocampal PGC‐1α, FNDC5, BDNF and other cognition‐related gene expressions and hippocampal FNDC5 and BDNF protein expressions in both young and aged rats. Animals were separated into four groups as regards to age (young vs. aged) and training status (control vs. exercise training). Voluntary exercise training was performed for 90 d, and several behavioral assessments were applied. Following behavioral assessment, hippocampus tissues were obtained for analysis of gene expression of PGC‐1α, mTOR, ERK, SIRT1, cFOS, NF‐κB, ARC and FOXO and gene and protein expressions of FNDC5 and BDNF. Locomotor activity and spatial memory were lower but anxiety scores were higher in the aged rats (P < 0.05). Exercise training enhanced these variables in both young and aged rats (P < 0.05). Hippocampal BDNF, FNDC5, PGC‐1α, mTOR, ARC, cFOS, ERK, SIRT, and FOXO expressions decreased, but NF‐κB expressions increased in aged rats (P < 0.05). Exercise training ameliorated these variables in both young and aged rats (P < 0.05). Similarly, hippocampal BDNF and FNDC5 protein expressions were lower in the aged rats and exercise training elevated them in both young and aged rats (P < 0.05). According to these results, we concluded that aging‐induced cognitive dysfunction is mainly associated with decreased hippocampal expression of PGC‐1α, FNDC5, and BDNF and exercise training improves cognitive functions via activating these molecules in the hippocampus.Support or Funding InformationThis work was supported by the Selcuk University Scientific Research and Project Coordinatorship (project number: 15401171).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Cyclosporin A Induces Hypertension via a Cholesterol‐ and ENaC‐Dependent Mechanism
Authors: Linck Valerie , Zou Li , Zhai Yu‐Jia , Eaton Douglas C. , Ma He‐Ping 
Published: June 2021

Hypertension related to the use of immunosuppressive drugs, particularly cyclosporin A (CsA), presents one of the major problems in the management of transplant recipients. Our recent studies suggest a hypothesis that CsA may cause hypertension by stimulating the renal epithelial sodium channel (ENaC) via a pathway associated with elevated intracellular cholesterol (Cho). To further determine the mechanism, we performed confocal microscopy and patch‐clamp experiments using cultured cortical collecting duct (CCD) principal cells and measured the blood pressure in mice. Confocal data show that CsA and Cho increased both the length of microvilli of CCD cells where ENaC is located and the levels of phosphatidylinositol‐4,5‐bisphosphate (PIP2) in microvilli. Conversely, inhibition of Cho synthesis with lovastatin decreased the levels of PIP2, a well‐known ENaC activator. Patch‐clamp data shows that Cho increased ENaC activity in a PIP2‐dependent manner. Interestingly, CsA elevated the blood pressure in mice and the elevation was abolished by either inhibition of Cho synthesis with lovastatin or blockade of ENaC with amiloride. These results suggest that CsA increases the blood pressure of mice by stimulating ENaC via a pathway associated with the elevation of intracellular Cho and PIP2 in the principal cells of CCD. However, it remains to be determined whether statins or amiloride can be used for the treatment of CsA‐induced hypertension.Support or Funding Information(Supported by NIH R01DK100582 to H.M.)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.