bluuebunny/crossref_metadata_2025_split huggingface dataset:
Probiotics prevent death caused by Citrobacter rodentium infection in neonatal mice via T cells
Authors: Gareau Mélanie G , Wine Eytan , Reardon Colin , Perdue Mary H , Sherman Philip M 
Published: June 2021

Intestinal infections cause morbidity and mortality, particularly in young children. C. rodentium challenge of mouse pups is used as a model to study neonatal enteric infections.AIMSDetermine if neonatal mice become sick after infection with C. rodentium and if probiotics can ameliorate disease.METHODSMouse pups were infected with C. rodentium by orogastric gavage at 14d of age and some pups pre‐treated with probiotics daily 1 wk prior to infection and onward. For others, the dam was given probiotics in drinking water to determine if probiotics act indirectly. Immune‐deficient (Rag1−/−; JH) pups were used to study the role of adaptive immunity in mediating the effects of probiotics on infection.RESULTSAt 10d post‐infection (PI), infected pups lost weight and displayed colonic epithelial cell hyperplasia, compared to sham‐infected animals. By 12 days PI, death occurred in infected pups (C. rodentium; 75% vs sham; 0%). Pre‐treatment with probiotics prevented death (probiotics; 17%), reduced epithelial hyperplasia and weight loss. Probiotics did not prevent death when administered either to the mother or Rag1−/− pups, but JH, B cell deficient pups survived.CONCLUSIONC. rodentium infection causes death in mouse pups. Probiotics prevented these effects, but only in the presence of T cells. Probiotics may serve as an option for therapy in newborns at high risk of developing infections.
Impact of Hydroxyl Radicals on Calcium Handling and Myofilament sensitivity in Isolated Myocardium
Authors: Hiranandani Nitisha , Janssen Paul ML 
Published: June 2021

ObjectiveHydroxyl radicals (OH*) are involved in the pathogenesis of reperfusion injury, which is observed in many clinical situations including acute heart failure, stroke and myocardial infarction. Two different sub‐cellular defects are involved in the phenotypical OH*‐injury, deranged calcium handling and alterations of myofilament responsiveness.MethodWe temporarily delineated the impact of these two mechanisms at different time points on OH* injury. In order to elucidate the injury response, we measured the amplitude and kinetics of calibrated intracellular Ca2+ transients and twitch contractions simultaneously using ionophoretically loaded bis fura‐2 and potassium contracture.ResultsAfter the exposure of OH* in rabbit trabeculae injury initially there is a marked increase in resting tension (6.27± 0.71 to 46.4 ± 3.49 mN/mm2) in parallel with an increase in diastolic calcium (136.6 ± 7.65 to 779.4 ± 64.63 nM) (n=8). We observed these parameters until a new steady state level was reached. At this new baseline, diastolic calcium returned to near‐normal levels to pre‐OH* levels whereas diastolic force declines, but not all the way to pre‐OH* levels, indicating a sustained injury. We also observed myofilament sensitivity before and after OH* injury through potassium contracture. Myofilament response was increased at the new baseline after OH* injury as compared to the pre‐OH* state.ConclusionThis indicates the acute injury that occurs after OH* exposure is mainly if not entirely is due to calcium overload in acute phase while sustained myocardial dysfunction is mainly due to the altered/increased myofilament responsiveness.
Key role of CFTR for all modes of intestinal HCO3− secretion
Authors: Singh Anurag Kumar , Zheng Wen , Sjöblom Markus , Seidler Ursula 
Published: June 2021

BackgroundCF patients suffer from a variety of gastrointestinal problems, which may all be directly or indirectly linked to the inability of the intestinal mucosa to secrete HCO3− and to inhibit Na+/H+ mediated fluid absorption and proton secretion.AimTo delineate the dependency of different modes of intestinal HCO3− secretion on CFTR expression.Methods and ResultsWe studied acid‐, agonist‐, and HCO3− stimulated, as well as Cl−‐dependent HCO3− secretion in the CFTRtm1cam and WT murine duodenum in vivo. NHE3 and Slc26a6‐deficient mice were used for selected questions. In WT mice, luminal acid, forskolin, heat‐stable E. coli enterotoxin (STa), PG E2, carbachol, and an increase of blood HCO3− all stimulated duodenal HCO3− secretion in anesthetized WT but not in CFTRtm1cam mice. Pharmacological inhibition or genetic ablation of NHE3 resulted in a significantly higher basal HCO3− secretory rate, which was electroneutral and therefore due to an unmasking of apical Cl−/HCO3− exchange activity. Accordingly, Slc26a6 as well as Slc26a3 ablation attenuated S1611‐induced JHCO3‐. In the absence of CFTR, electroneutral NaCl absorptive rates were similar to wt rates, but S1611 induced virtually no increase in HCO3− secretion.ConclusionThis indicates that the apical anion exchangers Slc26a6 and Slc26a3 need proton recycling via NHE3 to operate in the Cl− absorptive mode, and Cl− exit via CFTR to operate in the HCO3− secretory mode.
Stretch‐Induced Transcriptional Regulation of the Large Conductance Calcium‐Activated Potassium Channel (BK)‐β4 Subunit in Human Mesangial Cells (MC)
Authors: Irsik Debra L , Liu Liping , Grimm P Richard , Holtzclaw J David , O'Neil Roger G , Sansom Steven C 
Published: June 2021

Renal nephropathy is a complication of Type 2 Diabetes. In hyperinsulinemic mice, hyperfiltration transmits stretch to MC. A stretch‐induced increase in [Ca2+]i can activate the calcineurin/ Nuclear Factor of activated T cells (NFAT), a transcription factor that associates with GATA in smooth muscle. In physiological conditions, the pore‐forming BK‐α interacts with the β1 to regulate mesangial contractile tone. However, the mouse glomerulus also contains the β4 and only the glomerular β4 is up‐regulated (immunohistochemical staining) in hyperinsulinemic mice. Our underlying hypothesis is that stretch due to hyperfiltration increases the expression of β4 and that BK‐α /β4 causes a sustained elevation in [Ca2+], causing MC expansion. Using nested RT PCR, following 10% cyclical stretching (24 h; Flexercell), β4 expression was 6‐fold > (p< 0.05) and β1 was 50% < control. β4 protein level doubled after 2 hours of stretch. Using the Transcription Element Search System of the University of Pennsylvania, (TESS) we identified 6 GATA and 12 NFAT sites on the β4 promoter. Through ChIP, we confirmed that NFATc3 and GATA4 bind to the β4 promoter 1760 bases upstream of the transcription start site, yielding a 175 bp fragment identified by sequencing as β4.Conclusion(1) Stretching MC results in transcriptional up‐regulation of β4 and down‐regulation of β1 and (2) NFATc3 and GATA4 bind β4 at a consensus promoter site.
Expression, function and regulation of NH2‐terminal Sgk1 variants
Authors: Raikwar Nandita S , Kelley Elizabeth A , Snyder Peter M , Thomas Christie P 
Published: June 2021

Sgk1 is an aldosterone induced kinase that regulates epithelial sodium channel (ENaC)‐mediated Na+ transport. We identified N‐terminal variant Sgk1 isoforms: Sgk1_i2 and Sgk1_i3 that arise by alternate transcription initiation from human Sgk1 transcripts, Sgk1_v2 and Sgk1_v3 respectively. These isoforms are more resistant to proteosomal degradation as compared to Sgk1. Furthermore, aldosterone stimulates Sgk1_v3 mRNA expression in a collecting duct cell line, mpkCCDc14, indicating that this 5' variant may have a role in mineralocorticoid‐regulated Na+ reabsorption. When expressed together with ENaC subunits in FRT epithelia, Sgk1_i2 or Sgk1_i3 stimulate amiloride‐sensitive Na+ transport an effect that appears to be mediated via the kinase domain of Sgk1. Collectively, the data demonstrate that N‐terminal variants of Sgk1 are more stable, functionally more active and are expressed and regulated in collecting duct epithelia raising the possibility that these variants may have a physiological role.NHLBI and VA Merit
Inhibition of ENaC activity by the Influenza Virus M2 proton channel
Authors: Lazrak Ahmed , Iles Karen , Noah Diane L , Noah James , Matalon Sadis 
Published: June 2021

The mechanisms by which replicating influenza viruses decrease the activity of ENaC have not been elucidated. Herein we show that the influenza transmembrane protein (M2), a hydrogen channel, decreases levels and activity of ENaC in Xenopus oocytes, H441, and A549 cells transfected with a M2‐GFP cDNA. The regions of M2 protein responsible for this effect were localized to two separate portions of C‐terminus, between amino acids 52‐62 and 78‐82. This effect did not require M2 activation by low pH, and was prevented by MG‐132, a proteasome inhibitor. Furthermore, M2 has no effect when co‐expressed with ENaC bearing the Liddle mutations. Surface biotinylation of oocytes indicates that ENaC levels in cell membranes are reduced in the presence of M2. Pre‐treatment of both Xenopus oocytes and cells with GSH‐ester prevented the deleterious effects of M2 on ENaC. Together, these data suggest that M2 protein increases free radical production which results in ENaC endocytosis and proteasomal degradation by promoting increased ENaC ubiquitination. These results are the first indication that M2 regulates host ion channel function and suggest a mechanism for the influenza‐induced rhinorrhea and life‐threatening alveolar edema in humans.This Research was supported by NIH HL311979 grant to Sadis Matalon and NIH AI071393 grant to James Noah.
Effects of endurance running training and diet control on bone development and metabolism in young male rat
Authors: Chang Ming‐Yao , Huang Tsang‐Hai , Yang Ai‐Lun , Lin Che‐Fu , Lin Hsin‐Shin 
Published: June 2021

ObjectiveThe aim of this study was to investigate how endurance running and diet control affect growing bone.MethodsForty‐eight male Wistar rats (7 weeks old) were randomly assigned into four groups, which were control group (CON, n=12), high intensity running group (HIGH, n=12), low intensity running group (LOW, n=12), and diet control group (DCON, n=12). Animals in the High and Low groups underwent treadmill running 5 days/week for 8weeks. The DCON rats received mean quantity of chow consumed by exercise groups. Blood and bone samples were collected and stored for further analysis of serum marker, dynamic histology and geometry.ResultsAfter an eight‐week exercise training, body weight gain of the CON group was significantly higher than other three groups. Regarding dynamic histology assay, MS/BS (mineral surface/bone surface) did not show difference among groups. The CON group was numeric but not significantly higher in long bone cross‐sectional parameters. Tibiae length were higher in the CON group than other groups (p<.05). Serum calcium, phosphorus and insulin‐like growth factor‐I (IGF‐I) was significant lower in the DCON group (p<.05).Conclusions1) Similar to human studies, endurance running rats showed equal or somewhat lower values in bone tissue measurements, but no negative results revealed on bone turnover. 2) Diet control might cause an un‐equivalent physiology status in non‐exercise rats, which may not be appropriate to be set as a normal control group.Grant supported by National Science Council (NSC‐97‐2410‐H‐006‐083‐MY2, Taiwan).
Oxidative stress upregulates renal Angiotensin II type I receptors via activation of transcription factor nuclear factor‐kappaB
Authors: Javkhedkar Apurva Arvind , Banday Anees Ahmad , Lokhandwala Mustafa F 
Published: June 2021

Regulation of redox homeostasis is associated with normal functioning of cells, whereas oxidative stress is seen with various cardiovascular disorders like hypertension. Angiotensin II (Ang II), acting via Ang II type I (AT1) receptors, has known effects on the renal proximal tubular sodium transport, thus plays an important role in regulating blood pressure. Oxidative stress is also known to activate redox sensitive transcription factor NF‐kappaB and evidences indicate that AT1 receptor gene posses binding site for this transcription factor. Herein, we aim to investigate if oxidative stress upregulates renal AT1 receptors through NF‐kappaB activation. Human proximal tubular (HK‐2) cells were incubated with a pro oxidant L‐buthionine sulfoximine (BSO), an inhibitor of glutathione, for 48 hrs.ResultsCompared to control, there was an increase in levels of protein nitrotyrosination indicating oxidative stress in BSO treated HK‐2 cells. There was also activation of NF‐kappaB, upregulation of AT1 receptor protein, and increased Ang II‐induced Ca2+ signaling. Furthermore, treatment with pyrrolidine dithiocarbamate, a NF‐kappaB inihibitor, blocked NF‐kappaB activation, abolished AT1 receptor upregulation and exaggerated Ang II induced Ca2+ signaling.ConclusionThese results suggest that oxidative stress upregulates renal AT1 receptors via activation of transcription factor NF‐kappaB.Grant: AHA‐SDG‐0835428N
Transcriptional Regulation of Ceruloplasmin by FOXO1A and IL‐6
Authors: Hollenbach Andrew Durrell , Miller Patrick J. , Sidhu Alpa 
Published: June 2021

Ceruloplasmin (Cp), a six‐copper containing protein synthesized and secreted mainly by the liver, is an important extracellular anti‐oxidant and is part of the acute phase reaction during inflammation. The increase in hepatic expression and serum concentration of Cp during inflammation, infection, and trauma is primarily mediated by the inflammatory cytokine IL‐6. IL‐6 is known to positively regulate the transcription of Cp through its proximal promoter region. In addition, IL‐6 treatment localizes FOXO1A, a winged‐helix transcription factor, to the nucleus leading to its participation in IL‐6 induced gene expression. Microarray analysis showed that the expression of Cp increased 16 fold in the presence of a constitutively active FOXO1A. Consistent with this data we demonstrate for the first time that Cp is a direct transcriptional target of FOXO1A in an IL‐6 dependent manner. Through in vitro and in vivo mutational analysis, we identify the exact DNA recognition site for FOXO1A in the Cp proximal promoter region. We also demonstrate for the first time that both IL‐6 and FOXO1A are required for the transcriptional activity of Cp in HepG2 cells, identifying an additional role of FOXO1A in the inflammatory process.Funding: National Institutes of Health Centers of Biomedical Research Excellence (1 P20 RR020152) and the Louisiana Cancer Research Consortium Competitive Advantage Fund
B. subtilis Elongation Factor Tu binds Calcium ions
Authors: Dominguez Delfina C , Lopes Rosana , Palomino Javier 
Published: June 2021

ABSTRACTAn essential step toward the understanding of the role of calcium in prokaryotes is the identification of intracellular calcium‐binding proteins. In this report we present evidence that Bacillus subtilis elongation factor EF‐Tu is a calcium‐binding protein.A genomic analysis of EF‐hand related sequences in the genus Arabidopsis showed that elongation factors have EF‐hand domains. Considering the high degree of conservation across species and based on previous findings in our laboratory suggesting EF‐Tu may be a CaBP (unpublished results) we investigated further the B. subtilis EF‐Tu. We performed multiple sequence alignment and motif discovery of bacterial EF‐Tu and D. discoideum calmodulin sequences and the results suggested the presence of a possible calcium binding site in B. subtilis EF‐Tu. Secondary structure prediction indicated that the conserved acidic amino acids were found within a loop flanked by two helices. A recombinant B. subtilis EF‐Tu was partially purified. The protein was identified by Western blot assay using anti‐EF‐Tu antibodies and two‐dimensional electrophoresis followed by liquid chromatography and mass spectrometry. Calcium binding was examined, in vivo and in vitro, by 45Ca‐autoradiography and immunodetection using monoclonal anti‐calmodulin and polyclonal anti‐EF‐hand antibodies the combined results indicated the B. subtilis EF‐Tu bindis calcium ions in vivo and in vitro. Addition of calcium chelators EGTA/BAPTA or CaCl2 to cell cultures affected expression of B. subtilis EF‐Tu.
Maternal diabetes suppresses intrauterine kidney growth in male but not female ACI rats
Authors: Lane Pascale H , Commers Tessa , Shull James D 
Published: June 2021

Maternal diabetes (MDM) increases the risk of kidney abnormalities in offspring. The ACI rat has a 10‐15% risk of renal anomalies, especially aplasia, in normal pregnancy, but the effects of MDM in this strain is unknown. Female ACI rats received streptozocin or buffer, and MDM was confirmed 2‐3 days later by glucose measurement. Females were then housed with males until pregnancy was confirmed. Blood glucose was monitored every 3 days throughout gestation. After delivery, pups were studied for kidney anomalies and weight on day 3‐5 of postnatal life. Litter size and sex distribution were similar regardless of MDM, as was the rate of renal agenesis. Pup weight was reduced with MDM in males (8.3±0.2 vs 7.0±0.4g; p<0.01) but not in females (7.8±0.3 vs 7.5±0.4g). Kidney weight also showed sex‐specific reductions with MDM.MDM has been shown to reduce kidney weight and nephron number in rats, but the interaction of pup sex and MDM has not been previously described. Given interactions between reproductive and urinary structures in embryogenesis, sex‐specific problems are not surprising. Further study is needed to determine if this phenomenon occurs in other rat strains or if this is particular to the ACI rat.
Construction of a Physical Model of a Voltage‐Dependent Potassium Ion Channel
Authors: Kostow Nora , Silverstein Erica , Sosa Zach , Weinstein Emma , Scovell Ted , MacKinnon Roderick 
Published: June 2021

A partnership between students and Roderick MacKinnon enabled the Friends Seminary SMART Team (Students Modeling A Research Topic) to explore the structure and function of a chimaeric voltage‐gated K+ channel (Kvc) and to build a 3D physical model of its open conformation.Kvc are located along membranes of neurons and help repolarize the cells by allowing K+ to enter. The homo‐tetrameric Kvc we modeled consists of sensors that surround the pore helices, which form the central pore through which the K+ flows. On one end of the pore is a selectivity filter, which ensures that only K+ enter, and on the other end is the gate, which is either open or closed depending on the voltage around the membrane.A cleft in the sensor enables the paddle, a region of the sensor rich in positively charged residues, to monitor the separation charge across the membrane. In Kvc's open conformation, the paddle is attracted to the negatively charged extracellular fluid. After enough K+ flows out, the fluid around the paddle becomes more positively charged and repels the paddle to the other side of the membrane. This movement shifts the position of the S4‐S5 linker, which connects the sensor to the pore helices. The movement of the S4‐S5 linker in turn pushes the gate of the Kvc closed. When the intracellular fluid becomes more positively charged, Kvc returns to its open conformation. Supported by a grant from the HHMI Pre‐College Science Education Program.
Threonine requirement increases in late pregnancy
Authors: Levesque Crystal L , Moehn Soenke , Pencharz Paul B , Ball Ron O 
Published: June 2021

The metabolism in early pregnancy focuses on development of maternal body tissue. In late pregnancy fetal, and mammary growth increases the demand for nutrients. This change in metabolic focus is hypothesized to result in a higher requirement for amino acids during late pregnancy (3rd trimester) compared to early pregnancy (1st trimester). The threonine (THR) requirement was determined using the indicator amino acid (IAA) oxidation method in six multiparous sows. Sows received diets ranging from 60 to 150 % of the current recommended THR intake of 10 gd−1 based on BW, expected pregnancy gain and litter size. L[1‐13C]phenylalanine was given orally in 8 ½‐hourly meals as IAA and expired 13CO2 was quantified. Data was analyzed with a nonlinear Mixed model. Sow BW gain and reproductive performance was similar to commercial standards. There was a 2 fold difference in THR requirement. The THR requirement in early pregnancy was no more than 6.1 gd−1 (R2=0.56) and in late pregnancy no less than 13.6 gd−1 (R2=0.59). The THR requirement of the sow is substantially higher in late pregnancy than currently recommended. Nutritional regimes in pregnancy should account for changes in AA requirement to reduce the risk of overfeeding AA in early pregnancy and underfeeding AA in late pregnancy.Funding: AB Pork, ON Pork, AB Livestock Industry Development Fund, ACAAF, Ajinomoto Heartland.
Considerations for the safe and effective use of iron interventions in areas of malaria burden
Authors: Namaste Sorrel , Raiten Daniel 
Published: June 2021

ObjectiveA technical report is presented that addresses key elements affecting the safe and efficacious use of iron in areas of malaria burden.MethodsThe Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) of the National Institutes of Health (NIH) assembled a Technical Working Group (TWG) to draft a report as part of a larger NICHD/Bill and Melinda Gates Foundation project. The report consists of 1) mechanisms of iron adverse effects in the context of malaria 2) biomarkers of iron exposure, status and function 3) safety and effectiveness of iron interventions.ResultsResearch priorities identified by the TWG in the three core areas and presented in the context of malaria included: 1) clarification of the relative roles of plasma unbound iron; hepcidin; iron deficiency; and the interaction between iron and immune function. 2) adapt serum transferrin receptor/ferritin ratio for use in resource‐limited settings; refine iron assessment during infection; and improve methods to evaluate iron status in pregnancy and children <1yr. 3) establish the relative safety of iron delivered via various systems (e.g., fortification (home/manufactured), supplements, or slow release systems).ConclusionsThis report will be used to guide a consultative process, lead by the World Health Organization, to revise existing guidelines for iron interventions.
Folate intakes and blood concentrations of adults in NHANES 2003‐2004
Authors: Vanderwall Cassandra Mae , Tangney Christy , Kwasny Mary , Gustashaw Kristin 
Published: June 2021

High folate intake (>400μg) among older persons may result in adverse health outcomes and likely produce elevated serum folate concentrations, as shown in earlier National Health and Nutrition Examination Surveys (NHANES). We examined the impact of folate fortification and supplement use on intake and circulating folate concentrations of persons >45 years in NHANES 2003‐2004 stratified by gender and four race‐ethnicity groups: non‐Hispanic white (NHW), non‐Hispanic black (NHB), Mexican American (MA) and Other (O).NHB and NHW men consumed less refined, non‐whole grains than O males (p=0.008) and less legumes than MA and O (p=0.019). MA women consumed more grains (p=0.007) than NHW and NHB races, and more legumes than all races (p=0.006). NHB men had the lowest mean red blood cell (RBC) folate concentrations (p<0.001) and the lowest mean serum folate concentrations (p=0.003) of all races, while NHW women had the highest serum concentration (p=0.001). Female folate‐containing supplement users consumed more food folate than non‐supplement users (p=0.012). All supplement users are at risk of high serum folate concentrations and older (>65 years), NHW women who use supplements are more likely to have elevated RBC folate concentrations. These findings highlight the need to better understand the effects of chronic exposure to elevated folate intakes.