bluuebunny/crossref_metadata_2025 huggingface dataset:
Campylobacter jejuni disrupts polarized TLR9 signaling in colonic epithelial cells
Authors: O'Hara Jennifer , Friis Lorna , Feener Troy , Szymanski Christine , Beck Paul
Published: June 2021

Campylobacter jejuni infection is associated with an increased risk of developing inflammatory bowel disease (IBD) via mechanisms that remain obscure. TLR9 signaling in response to bacterial DNA is essential to intestinal homeostasis, possibly by regulating the T helper (Th) 17‐cell line. IL‐25 is a known inhibitor of the proinflammatory Th17 pathway.

Aim

To assess whether C. jejuni contributes to the development of IBD by disrupting TLR9 signaling using a human colonic (T84) cell line and a DSS model of colitis.

Results

Apical application of a TLR9 agonist (ISS‐ODN, 5μg/mL) elicited a significant increase in transepithelial resistance across control T84 monolayers, indicating a tightening of the epithelial barrier. This response was lost in C. jejuni‐infected monolayers. Infected cells secreted significantly more IL‐8 in response to a basolaterally applied TLR9 agonist when compared to control cells. Real‐time PCR revealed a greater than 2 fold increase in TLR9 expression in human colonic biopsies exposed to C.jejuni. C57Bl/6 mice inoculated with 1 × 108 C.jejuni demonstrated an increase in occult blood score and a significant reduction in colonic IL‐25 levels following treatment with DSS compared to mice treated with C. jejuni or DSS alone.

Conclusions

C. jejuni may increase the risk of developing IBD by disrupting epithelial TLR9 signaling and reducing IL‐25 levels. Funded by CAG‐CIHR‐CCFC.
Respiratory syncytial virus hijacks the tumor‐suppressor p53 to enhance its replication in lung epithelial cells
Authors: Gibbs John D , Bian Tao , Menendez Daniel , Resnick Michael A , Imani Farhad
Published: June 2021

Respiratory syncytial virus (RSV) infection is the major cause of childhood lower respiratory illness and has been associated with the induction and exacerbation of asthma. Previously, we reported that RSV infection induced TGF‐β expression that caused cell cycle arrest and subsequently enhanced RSV replication. In the current study, we demonstrate that a downstream target of TGF‐β signaling; P53, is a pivotal transcription factor for RSV replication. Over‐expression of p53 protein by an inducible system (Tet‐off) enhanced RSV replication by 9 folds, whereas, knockdown of p53 using siRNA significantly reduced RSV replication in H1299 and A549 lung epithelial cell lines. Stabilization of p53 with nutlin‐3 enhanced RSV replication by 8 folds in primary human lung epithelial (PHBE) cells. We hypothesized that a plausible mechanism of enhanced RSV replication by p53 was through direct binding of p53 to RSV RNA. A search of RSV genome revealed several putative p53‐responsive elements. To confirm interaction of p53, EMSA analysis was performed which showed a specific shift with one of the p53 response elements. Taken together, we have identified a novel role for p53 in positive regulation of RSV replication. These findings suggest that enhanced p53 expression through lung injury, smoking or air pollution could facilitate a significant increase in RSV replication leading to more severe respiratory pathologies.
Decreased expression of Paneth cell antimicrobial peptides coincide with bacterial translocation after starvation
Authors: Hodin Caroline M , Lenaerts Kaatje , de Haan Jacco‐Juri , Grootjans Joep , Hadfoune M'hamed , Hooper Lora V , Heineman Eric , Buurman Wim A
Published: June 2021

The lack of enteral feeding, with or without parenteral nutritional support has been reported to result in increased translocation of bacteria, which is considered to play an important role in the high morbidity and mortality rates of critical illnesses such as acute pancreatitis. Recently, Paneth cells, important constituents of the innate intestinal immunity, were shown to be crucial in host protection against invasion of both commensal and pathogenic bacteria.

This study investigates the influence of food deprivation on Paneth cell function and small intestinal integrity. Significant decreases in RNA expression of lysozyme (p< 0.01), cryptdin (p< 0.05) and RegIIIγ (p<0.05) were seen after 48 hours of food deprivation in C57BL/6 mice (n=15/group). Accordingly, protein expression of lysozyme and the precursor form of RegIIIγ were also shown to decrease significantly (p<0.01, p<0.05 respectively). Furthermore, increased bacterial translocation to mesenteric lymph nodes occurred (p<0.01), while HE staining showed normal intestinal architecture, distribution and expression of respectively tight junction proteins zonula occludens‐1 and claudin‐3 were unchanged.

In conclusion, the current study demonstrates that enteral starvation causes Paneth cell dysfunction paralleled by increased bacterial translocation without disturbances of the small intestinal physical barrier.
Intravascular flow fields shape intussusceptive pillars in the chick chorioallantoic membrane
Authors: Lee Grace S. , Filipovic Nenad , Milosevic Zarko , Miele Lino F. , Lin Miao , Simpson Dinee C. , Konerding Moritz A. , Tsuda Akira , Mentzer Steven J.
Published: June 2021

Intussusceptive (nonsprouting) angiogenesis is an essential process in the development of the chick chorioallantoic membrane (CAM). The influence of intravascular flow fields on intussusceptive pillar formation in the CAM, however, remains largely unknown. Using fluorescent vascular tracers and digital time‐series video reconstructions, intussusceptive pillars and the surrounding flow fields were identified during the development days 12–16. The mechanical forces within the CAM vessels, including wall shear stress, velocity, and blood pressure, were mapped using 3D finite element models and computational flow simulations. The pillars demonstrated a quasi‐circular circumference (shape factor 0.41+0.13) and comprised 1.7+1.2% of the bifurcation cross‐sectional area within 2nd and 3rd order vessels. The presence of pillars was independent of vessel diameter (R=0.32) or bifurcation angle (R=0.48) (p>0.4), but blood flow surrounding the pillars demonstrated a narrow range of velocities. More importantly, the location and geometry of the pillar correlated closely with the streamlines of the dominant vessel flow (p=0.02). We conclude that these spatial dynamics reflect a responsiveness of blood vessels to intravascular flow fields and indicate the importance of mechanical forces in shaping both intussusceptive angiogenesis and vessel structure in the microcirculation.

Grant Funding Source: NIH Grant HL47078, HL75426 and HL94567
Functions and conrol of p53 in embryonic stem cells
Authors: Barton Michelle , Jain Abhinav , Allton Kendra
Published: June 2021

We are focusing on the roles of p53 in human and mouse embryonic stem (ES) cells, and have identified chromatin interactions of p53 by genome wide, deep sequencing of chromatin immunoprecipitates. There are major differences between human and mouse stem cell response to DNA damage. To address mechanisms of endogenous p53 regulation in stem cells, we created a new mouse and stem cell model by knock‐in of a tandem‐affinity‐purification (TAP) epitope at the endogenous Trp53 locus. With this approach, we identified Tripartite‐motif protein 24 (Trim24), a previously unknown partner of p53. We found that Trim24 is an RING‐finger, E3‐ligase that ubiquitylates and negatively regulates p53 levels. TRIM24 is degraded and p53 is induced during differentiation of human ES cells, to effect a transient G1/S arrest in response to retinoic acid treatment. Depletion of TRIM24 in human ES cells causes spontaneous differentiation, in contrast to human breast cancer cells where TRIM24 depletion induces spontaneous apoptosis. TRIM24 has PHD and Bromo structural domains, and regulates p53 and p53‐dependent functions by chromatin‐dependent and–independent mechanisms. TRIM24 is aberrantly expressed in a number of human cancers and may be a useful therapeutic target.
C‐kit+ cardiac precursor cells exhibit a unique oxidant and antioxidant gene expression profile
Authors: Spealman Alyson Korry , Guruju Mallik , Poor Daniel , Sharma Ram V. , Kotlikoff Michael I. , Davisson Robin L.
Published: June 2021

Evidence suggests that there are small populations of stem cells residing in the postnatal heart, and perhaps in the adult myocardium. Research from our laboratory demonstrates that c‐kit+ cells isolated from the hearts of c‐kitBAC‐EGFP mice can be expanded and differentiated in vitro into all three lineages of the heart. Since redox mechanisms play critical roles within stem cell niches, and also have distinct roles in cell signaling and death, we hypothesized that c‐kit+ cells exhibit a unique redox profile compared to control cardiomyocytes. Utilizing RT2Profiler PCR Arrays to investigate mRNA expression of 84 genes involved in oxidative stress and antioxidant defense, we found that 23 genes were upregulated and 4 genes were downregulated in c‐kit+ cells compared to controls. Upregulated genes included two superoxide dismutase isoforms (Sod1, Sod2), four members of the peroxiredoxin family (Prdx2, Prdx3, Prdx5, Prdx6), and myoglobin. The four downregulated genes included the third member of the Sod family (Sod3) along with apolipoprotein E, cytoglobin, and neutrophil cytosolic factor 2. Fold changes were considered significant at above 2‐fold and p<.05. These data reveal a unique redox profile in c‐kit+ cells, and may provide targets for improving survival, proliferation, and/or differentiation of these cells in vitro and, eventually, following cardiac damage in vivo.

Grant Funding Source: HL063887, AHA 0540114N
Defining the Role of the Student Teaching Assistant in Gross Anatomy
Authors: Christensen Kevin Nicholas , Nyauncho Clive P , Hassinger James Peyton , Scoville Elizabeth , Kumar Neha , Pawlina Wojciech , Lachman Nirusha
Published: June 2021

Teaching assistants (TA's) are an important resource in facilitation of 1st year courses at Mayo Medical School. Formal student teaching positions are available to 3rd students seeking opportunities to develop and refine peer teaching skills. While the Gross Anatomy course has traditionally utilized TA's as peer teachers the role of the TA has not been formally defined. Student evaluations as well as structured faculty and TA interviews were used to quantitatively assess how well TAs perceived their achievement of those goals compared to student and faculty perception. Expectations of TA's role include peer teaching through formal delivery of briefing sessions, group supervision during laboratory sessions, preparation of prosections, organization of review and informal practical examination sessions. TA's may extend their interaction with students through tutoring and participate in medical education‐based research projects. Furthermore, TA's are role players in assessment of student course performance. TA perception of their ability to meet expectations matched faculty and student perceptions. Student evaluations showed TA's to be one of the most highly rated resources in their teaching and learning and valued TA's for their capacity to relate to them, provide hands‐on clinical applications for basic science concepts, emotional support, time commitment to tutoring and assistance in the laboratory.

Grant Funding Source: Mayo Medical School
Wnt/β‐catenin signaling represses heart muscle development via GATA transcription factors
Authors: Hoppler Stefan Peter , Lavery Danielle Lynn , Afouda Boni Anatole , Martin Jennifer
Published: June 2021

Inhibition of Wnt/β‐catenin signalling is required in vertebrate embryos for initiation of heart development. The identity of the endogenous Wnt ligand that needs to be inhibited has so far remained unclear.

We identified Wnt6 to be expressed close to the heart forming tissue in Xenopus. Endogenous Wnt6 expression is required during organogenesis to prevent differentiation of an abnormally large heart muscle. Even at these remarkably late stages, Wnt6/β‐catenin signalling regulates the pro‐cardiogenic transcription factor network rather than heart muscle differentiation directly.

Our loss‐of‐Wnt6‐function experiments suggest a sequential deregulation of cardiogenic markers, with GATA genes deregulated earliest. We find that GATA genes are not only among the cardiogenic genes repressed by Wnt/β‐catenin signalling, but that reinstating GATA function experimentally will rescue subsequent heart muscle development. This result suggests that Wnt/β‐catenin signalling primarily restricts GATA expression in the cardiogenic mesoderm; and that where Wnt signalling does not repress GATA expression; GATA factors drive subsequent heart development.

Wnt/β‐catenin is usually associated with transcriptional activation rather than repression. However, our recent experiments with protein‐synthesis inhibitor suggest that Wnt/β‐catenin is capable of repressing GATA gene expression directly.
Shape differences in the bony pelvis of women with and without pelvic floor disorders
Authors: Brown Kirsten , Handa Victoria , Macura Katarzyna , DeLeon Valerie
Published: June 2021

Pelvic floor disorders (PFDs) include a suite of urinary and gastrointestinal tract problems that have a negative impact a woman's quality of life and effect up to one‐third of women. Earlier studies focused on width of the pelvis as a risk factor for PFDs. This is the first study to address the association of complex 3D pelvic shape with PFDs. We hypothesize that insertion sites of the muscular pelvic diaphragm are displaced further from one another in women with PFDs relative to unaffected controls. This study uses 3D geometric morphometrics to analyze the bony pelvis in a clinical sample of women with (n=6) and without (n=11) PFDs. Landmarks (k=41) were collected on pelvic reconstructions from MR data. Generalized Procrustes Analysis (GPA) and Euclidean Distance Matrix Analysis (EDMA) were used to localize shape differences between the control group and the affected group.

GPA analysis identified significant shape differences between the two groups (α<.05); relative to other landmarks, the sacrum and ischial spines move posteriorly, and the iliac blades move medially and superiorly in women with PFDs. EDMA analyses demonstrated that the majority of differences between groups included the posterior displacement of the sacrum and antero‐posterior elongation of the birth canal. These results suggest that the posterior elongation of the pelvic diaphragm may be a better predictor of risk for PFD than pelvic width alone.

Grant Funding Source: none
Learning, teaching & Web 2.0: Finding a comfortable fit
Authors: McGee Patricia
Published: June 2021

Web 2.0 tools are those that are web‐based, typically free to the user, support collaboration and interaction, and are responsive to the user. These increasingly available tools include wikis, blogs, and various file‐sharing services. Freely available and appealing, these tools are not designed for teaching and learning, yet have been embraced by learners and educators alike. Web 2.0 tools offer alterative instructional strategies that can support deeper learning through active construction of knowledge, social negotiation of understanding, and learner‐produced content.
Myocardial BMP Can Promote Orientated Protrusion of the Proepicardium Necessary for Entry of Coronary Vessel Precursors and Epicardial Progenitors to the Heart
Authors: Garriock Robert John , Ishii Yasuo , Navetta Alicia , Mikawa Takashi
Published: June 2021

The coronary vessel precursors and epicardium derive from a separate tissue rudiment outside of the heart called the proepicardium (PE). The PE protrudes to the heart and makes contact with the atrioventricular junction/inner curvature (AV/IC) region despite being closer to the sinoatrium. The attachment of the PE to the heart is an essential step in coronary vasculogenesis and formation of the epicardium. However, it is unknown how the specificity of PE attachment to the AV/IC is achieved. We demonstrate that BMP‐signaling from the myocardium specifies the attachment site of the PE to the heart. We show that Bmp2, which is expressed specifically at the AV/IC region of the heart, can signal alternative sites of PE attachment when misexpressed outside the AV/IC region. In contrast, misexpression of a BMP‐antagonist, Noggin, blocks PE attachment to the heart. Finally, PE explants preferentially protrude toward the AV/IC and this preference can be mimicked by BMP2/4. These results support a model in which BMP signals from the myocardium regulate PE protrusion and contact with a specific site on the heart.

Grant Funding Source: NIH
Computational Analyses of Endocardial Cell Motion During Cardiovascular Morphogenesis in Transgenic Avian Embryos
Authors: Aleksandrova Anastasiia , Czirok Andras , Lansford Rusty D , Szabo Andras , Little Charles D , Rongish Brenda J
Published: June 2021

Conventional dogma suggests that cardiac progenitors migrate to the midline to form a tubular heart, comprised of concentric myocardial and endocardial layers separated by extracellular matrix (ECM). Here we describe the motility of fluorescently tagged (Tie1‐YFP) endocardial progenitors in transgenic quail embryos using epifluorescent time lapse imaging. To visualize the extracellular matrix environment of migrating progenitor cells, we labeled fibronectin and fibrillin‐2 in vivo by microinjection of fluorochrome‐conjugated monoclonal antibodies. Imaging was performed at early stages, encompassing tubular heart assembly and early looping. We determined the relative importance of directed cell autonomous motility versus passive tissue movements in the assembly of a tubular heart. We established the motion of cells and fibrils of multiple ECM components using both object tracking and particle image velocimetry (image cross correlation). These quantitative data indicate the contribution of cell autonomous motility displayed by endocardial progenitors is limited. Thus tissue‐level motion drives most of the cell displacements during endocardial morphogenesis. Studies using motility inhibitors and Tie1+ cell transplantation will assess the role of myosin II‐dependent directed endocardial progenitor cell migration in early stages of tubular heart morphogenesis.

Supported by NIH HL085694.

Grant Funding Source: NIH HL085694
Ccr4‐Not complex directly regulates transcription elongation
Authors: Reese Joseph C , Kruk Jennifer A. , Dutta Arnob , Gilmour David S
Published: June 2021

Many functions have been ascribed to the Ccr4‐Not complex. First described many years ago as a potential regulator of preinitiation complex (PIC) formation, more recently, a large body of evidence indicates it is predominantly cytoplasmic and regulates deadenylation of mRNA and ubiquitylation of substrates in the cytoplasm and nucleus. A direct role of this complex in transcription has not been demonstrated clearly, and the discovery of the cytoplasmic functions of this complex raises questions about how it regulates gene expression.

Here we provide conclusive evidence that Ccr4‐Not directly regulates RNAPII transcription elongation. Ccr4‐Not associates with active genes in vivo, and it predominantly associates with the open reading frames of genes in a transcription and RNAPII‐dependent manner. We show that Ccr4‐Not regulates multiple elongation functions, and interestingly, mutation of different subunits of this complex results in distinct elongation phenotypes. Interestingly, Ccr4‐Not associates with RNAPII in a CTD‐independent manner in vitro and in vivo. Furthermore, using a highly purified system, we demonstrate that Ccr4‐Not associates with RNAPII elongation complexes and stimulates transcription elongation. Together, our results bring to light the functions of the Ccr4‐Not complex in the transcription cycle and provide evidence that it contributes directly to transcription by RNAPII.
The mammalian target of rapamycin in translation and folding
Authors: Jacinto Estela , Oh Wonjun , Wu Chang‐chih , Facchinetti Valeria , Su Bing
Published: June 2021

Cell growth requires the synthesis of proteins and other macromolecules that are critical for increase in cellular mass and number. The mammalian target of rapamycin (mTOR) controls cell growth by regulating various aspects of protein synthesis. mTOR, in association with raptor and mLST8 (termed mTOR complex 1 or mTORC1), regulates translation in a rapamycin‐sensitive manner. mTOR also forms a structurally distinct complex with rictor, SIN1, and mLST8 (termed mTORC2). The function of mTORC2 and why this complex is insensitive to rapamycin are currently poorly understood. So far it is known that mTORC2 is involved in actin cytoskeleton reorganization and phosphorylation of Akt/PKB, an AGC kinase family member that becomes deregulated in cancer. Recently, we found that mTORC2 controls the folding and stability of Akt and conventional PKC by phosphorylation at the highly conserved turn motif site. This TORC2 function is growth factor‐independent and conserved from yeast to mammals. We will discuss how mTOR may function to link translation to protein folding. Our findings reveal the diversity of mTOR functions in the control of protein synthesis and cell growth. This work was supported in part by the American Heart Association 0530192N, American Cancer Society RSG0721601TBE, and NIH GM079176 (to E.J.) and NIH HL070225 (to B.S.)
Multidimensional Mass Spectrometry Using Shotgun Lipidomics to Identify Alterations in Lipid Signaling and Metabolism in Disease States
Authors: Gross Richard W
Published: June 2021

Lipids fulfill multiple pleiotropic roles in cellular function. Alterations in cellular lipid metabolism, trafficking and/or compartmentation contribute to the majority of mortality and morbidity in industrialized nations. Historically, lipid analysis was a time‐consuming process that required multiple sequential steps to identify and quantify a limited number of high abundance lipid molecular species. During the last 25 years, the use of mass spectrometry for global lipid analysis has revolutionized our ability to understand the role of lipids in multiple disease processes. Our laboratory has developed shotgun lipidomics procedures that can directly examine with high sensitivity the lipid composition of biologic tissues or fluids directly from their organic extracts. Through exploiting the intrinsic chemical properties of lipid classes in conjunction with intrasource separation, multidimensional mass spectrometry and array analysis, it is now possible to accurately identify and quantitate hundreds to thousands of both high and low abundance lipid molecular species directly from their biologic extracts. Through the development of multidimensional mass spectrometry, much progress has already been made in understanding the roles of alterations in lipid metabolism in many disease states including diabetic cardiomyopathy, obesity and neurodegenerative disorders. This talk will summarize progress in the lipidomics field with emphasis on the advantages and difficulties of the current approaches being employed. This research was funded by NIH Grant PO1HL57278.
Epithelial sodium channels and hypertension
Authors: Kleyman Thomas R
Published: June 2021

The epithelial Na channel (ENaC) mediates Na absorption in the most distal segments of the nephron, and has an important role in the regulation of extracellular fluid volume and blood pressure. Rare ENaC gain‐of‐function mutations have been described in an inherited form of hypertension, and rare loss‐of‐function mutations result in hypotension. ENaC polymorphisms associated with modest gains‐of‐function have been described. Whether these polymorphisms contribute to hypertension in selected populations remains to be determined. A number of factors influence ENaC function and may contribute to increases in ENaC activity under certain conditions. Proteolytic cleavage of ENaC at specific sites results in channel activation by releasing inhibitory tracts imbedded within the channel's alpha and gamma subunits. In certain pathologic states, enhanced ENaC cleavage may result in channel activation, renal Na retention and hypertension. For example, in the setting of nephrotic syndrome filtered plasminogen is converted to plasmin, which can cleave and activate the channel. (Supported by DK054354, DK065161 and DK079307)
The Biology of small RNAs
Authors: Sharp Phillip A.
Published: June 2021

MicroRNAs are currently thought to interact with mRNAs from half of all human genes, and each family of microRNAs is thought to target about 500 different mRNAs. Thus, these small RNAs form a complex network of cytoplasmic regulatory factors that complement the network of factors in the nucleus controlling transcription of genes. Overexpression of some microRNAs is associated with certain types of cancer while, more commonly, reduction in microRNA levels correlates with tumorigenesis. The latter is consistent with the recent finding that microRNA regulation is not essential for tumor growth. We have recently isolated several tumor cell lines that are defective for synthesis of all microRNAs but still capable of forming tumors. Recent evidence suggests that the primary role of microRNAs might be to provide robustness or stability to systems. Stability during stress is a form of robustness. We have recently found that cytoplasmic subcellular localization of mRNAs and microRNAs is dependent upon formation of poly(ADP‐ribose) and that microRNA repression is reduced under these conditions.
Defining the modular protein intereactions that coordinate recruitment of DNA polymerase alpha to initiate SV40 DNA replication
Authors: Fanning Ellen , Huang Hao , Zhang Haijiang , Weiner Brian E. , Chazin Walter J.
Published: June 2021

SV40 DNA replication, a simple but powerful model system, can be reconstituted with purified recombinant proteins in vitro, providing an opportunity to identify at the atomic level how a small number of eukaryotic proteins interact to initiate replication at a defined origin. Indeed four recombinant proteins suffice to initiate replication. Previous work from our labs and others suggests that origin melting by the viral helicase T antigen (Tag) leads to a transient ternary complex of Tag, RPA, and ssDNA. This complex dissociates as more ssDNA emerges from the helicase, generating RPA‐ssDNA parental template. Tag associated with DNA polymerase alpha‐primase (pol‐prim) is proposed to then remodel the bound RPA into a weaker binding mode, allowing pol‐prim to gain access to the exposed ssDNA and begin primer synthesis (EMBO J 25, 5516; NSMB 12, 332). This working model predicts that specific contacts of pol‐prim with the helicase domain of Tag are required to initiate replication. To further test the model, we determined the solution structure of the Tag‐interacting domain of pol‐prim regulatory subunit p68, characterized the binding surfaces of p68 and Tag, and will present evidence that interaction between these surfaces is needed for initiation in a reconstituted system. A model in which multiple defined protein interactions coordinate initiation of replication will be presented. (NIH GM52948 to EF and GM65484 to WJC)
Cellular Physiology of Bacterial Ribosome Assembly
Authors: Williamson James R.
Published: June 2021

The bacterial ribosome is composed of 3 large RNA molecules and 53 small proteins. The biogenesis and assembly of ribosomes accounts for approximately one third of the energy budget for a rapidly dividing bacterial cell, and is thus a central aspect of cellular physiology. Not surprisingly, the high level of synthesis of the ribosomal components is subject to tight regulation to ensure coordinated production of each component in the required amount. While some general principles of feedback autoregulation have been identified, understanding of the network of regulatory interactions that coordinates ribosome assembly is very incomplete.

We have developed a range of isotope pulse assays using 15N‐labeling to monitor ribosome assembly in rapidly growing E. coli. These experiments permit precise quantitation of free ribosomal protein levels, the levels of proteins in intermediate assembly particles, and the rate at which these particles turnover. Using chemical probes, protein overexpression, and analysis of deletion strains, we are developing a quantitative framework for understanding the process of ribosome biogenesis in bacteria.
Sirtuins regulate metabolic adaptation to energy status
Authors: Denu John Matthew , Hallows William , Smith Brian
Published: June 2021

Reversible protein acetylation is now recognized as a major regulatory mechanism for controlling diverse cellular processes. With the recent cataloging of ~1000 acetylation sites on hundreds of proteins comes the challenge of assigning functional roles to specific lysine acetylation, of identifying the acetyltransferases and deaceytlases responsible, and of elucidating the physiological cause and effect. The sirtuin family of deacetylases represents a class of enzymes that are linked to a variety of metabolic pathways. Sirtuins catalyze NAD‐dependent conversion of epsilon‐amino acetylated lysine residues to deacetylated lysine, nicotinamide, and O‐acetyl‐ADP‐ribose. Previously, we have shown that acetyl‐CoA synthetases are regulated by Sirt1‐ and Sirt3‐dependent deacetylation, resulting in modulation of acetate/acetyl‐CoA metabolism. To identify other novel substrates and pathways controlled by sirtuins, we have utilized a multifaceted molecular approach involving metabolomic analysis of tissues from knockout mice, protein acetylome analysis, enzyme kinetics and a new high throughput screening strategy that takes advantage of the sirtuin catalytic mechanism. Collectively, these data reveal that sirtuins regulate an unexpectedly broad range of metabolic pathways that include glycolysis, fatty acid oxidation, and the urea cycle.
The human milk microbiome: a potential influence on mammary health and bacterial colonization of the infant gut
Authors: Hunt Katherine Mary , Foster James A , Forney Larry J , Schütte Ursel M.E , Beck Daniel L , Williams Janet E , Collier Natalie N , McGuire Michelle K , McGuire Mark A
Published: June 2021

Our study investigated the microbiome of healthy human milk collected aseptically from 16 women over a 5‐wk period. Bar‐coded 454 pyrosequencing of 16S rRNA genes produced an average of 4,000 reads per sample, with Streptococcus, Staphylococcus, and Corynebacterium identified as the dominant phylotypes at the genus level when evaluated using the Ribosomal Database Project classifier. The ACE richness metric estimated from 180 to 1,700 distinct phylotypes (97% similarity) in each sample. The community composition of milk collected from each woman was relatively consistent over time; nonetheless, although profiles from each woman tended to cluster together, random shifts occurred at some time points causing drastic changes in microbial community composition. Data reveal that complexity of the milk bacterial communities is comparable to that found on skin or in the mouth, but less complex than that in the gut. In summary, human milk harbors a wide variety of bacteria that appear to change in composition at times perhaps due to environmental characteristics in the mammary gland related to diet, milk composition, or immune factors. These bacterial communities may play pivotal roles in mammary health and colonization of the infant gut. Supported by NIH‐NRRI grants P20 RR15587 and P20 RR16448, and the United Dairymen of Idaho.

Grant Funding Source: NIH‐NRRI grants P20 RR15587 and P20 RR16448, andthe United Dairymen of Idaho.
Non‐heme and heme iron absorption during pregnancy
Authors: Young Melissa F. , Griffin Ian , Pressman Eva , McIntyre Allison , Cooper Elizabeth , McNanley Thomas , Harris Leah , Westerman Mark , O'Brien Kimberly O.
Published: June 2021

Iron homeostasis during pregnancy has important implications for dietary recommendations/interventions. Our objectives were to examine heme and non‐heme iron absorption in 20 pregnant (16–32 y) and 12 non‐pregnant subjects (18–27 y). The clinical study included a 2‐day iron absorption study where subjects were randomly assigned to receive a heme meal (intrinsically labeled 58Fe) and a non‐heme iron supplement (57Fe ferrous sulfate) on alternate days. After two‐weeks a blood sample was taken to assess iron status, serum hepcidin and iron absorption based on red blood cell iron incorporation. Heme iron absorption was significantly higher than non‐heme iron absorption in both pregnant (47.9 ± 14.4 vs. 40.4 ± 13.2%, p=0.02) and non‐pregnant subjects (50.2 ±14.8 vs. 15.3 ± 9.7%, p<0.0001). Pregnant women absorbed significantly more non‐heme iron (p <0.0001) but not heme iron compared to non‐pregnant women. Hepcidin was directly associated with serum ferritin (p=0.0001, p=0.03) and total body iron (p=0.03, p=0.0008) in pregnant and non‐pregnant women. Serum hepcidin was inversely associated with 57Fe enrichment (non‐heme meal) (p<0.05) and a similar trend was evident with 58Fe enrichment (heme meal) (p=0.08) in healthy pregnant women. Unlike non‐heme iron, heme iron absorption does not appear to be upregulated during pregnancy.

Grant Funding Source: Cornell Univ. 2006‐07‐160, NIH Training Grant 5T32DK00715835, and ILS
Study of the acute impact of polyphenols from brown seaweeds on glucose control in healthy men and women
Authors: Lamarche Benoit , Paradis Marie‐Ève , Couture Patrick
Published: June 2021

This study examined the acute impact of polyphenols from brown seaweeds on post‐load plasma glucose and insulin concentrations in healthy subjects. Twenty‐three participants (11 men, 12 women) aged 24–55 years were recruited in this double‐blind randomized placebo controlled study. The test product consisted of two 500mg capsules of InSea2™, a commercial mix of polyphenols from brown seaweeds with known inhibitory action on α‐amylase and α‐glucosidase activities. Polyphenol and placebo capsules were consumed on each occasion 30 minutes prior to consumption of 50 g of available carbohydrates from bread. Plasma glucose and insulin concentrations were measured over a period of three hours post carbohydrate ingestion at pre‐specified time points. Both treatments were separated by one week. Acute consumption of the seaweed polyphenol mixture was not associated with any adverse event. Compared with placebo, acute consumption of seaweed polyphenols was associated with a non significant 3.6% reduction in the area under the curve (AUC) of plasma glucose concentration (P=0.16), a 5.9% reduction in the insulin AUC (P=0.031) and a 6.9% increase in the Cederholm index of insulin sensitivity (P=0.047). Responses were similar in men and women. These data suggest that polyphenols from brown seaweeds may alter the acute glycemic and insulin response to carbohydrate ingestion.

Funding: innoVactiv Inc.
Attenuation of common cold symptoms by encapsulated juice powder concentrate
Authors: Roll Stephanie , Nocon Marc , Willich Stefan N
Published: June 2021

Introduction

Dietary supplements have been suggested as preventive strategies for common cold, but previous results were inconsistent. This study aimed to assess the effect of a dietary supplement from fruits and vegetables on common cold symptoms in healthy healthcare professionals.

Methods

This was a randomized double‐blind placebo‐controlled trial. Subjects were taking four capsules of dietary supplement (Juice Plus+®) or matching placebo daily for eight months, including a two month run‐in period. We report means and 95% confidence intervals (CI) for the number of days with at least moderate common cold symptoms (primary endpoint) and number of days with any common cold symptoms. Differences between groups are analyzed with ANOVA.

Results

A total of 543 subjects were included, with 529 valid for primary analysis (intervention: 263, placebo: 266). The mean number of days with at least moderate common cold symptoms was 7.6 (95% CI 6.5–8.8) in the intervention and 9.5 (8.4–10.6) in the placebo group (P=0.023). The mean number of days with any common cold symptoms was 29.4 (25.8–33.0) in the intervention and 30.7 (27.1–34.3) in the placebo group (P=0.616).

Conclusion

Intake of a dietary supplement from fruits and vegetables was associated with a reduction of moderate or severe common cold symptoms, but not with a reduction of total days with common cold symptoms.

Research support: NSA (TN, USA)
Effect on serum lipids and lipoproteins of diets enriched with a terrestrial (flaxseed) versus algal‐oil (V‐Pure®) source of n‐3 fatty acids in healthy adults
Authors: Wien Michelle , Oda Keiji , Rajaram Sujatha , Haddad Ella , Sabaté Joan
Published: June 2021

Background

Algal‐oil supplements usually contain only docosahexaenoic acid (DHA). The algal‐oil based V‐Pure® supplement contains both eicosapentanenoic acid (EPA) and DHA, thus mimics fish oil supplements. However, the effects of consuming V‐Pure® on serum lipids, lipoproteins, apolipoproteins and their corresponding ratios are unknown.

Aim and Methods

To compare the effect on serum lipids, lipoproteins and apolipoproteins of diets enriched with a terrestrial source (flaxseed oil) of α‐linolenic acid (ALA) versus V‐Pure supplement (S), we performed a randomized cross‐over study (3 8‐week study periods) in 24 healthy adults (mean±SE age 42±2.7 years). Under controlled feeding conditions, subjects consumed eucaloric diets [10:1 n‐6:n‐3 ratio (Control), 2:1 n‐6:n‐3 ratio (flaxseed oil, ALA; 6–7g/2400 kcal/d) and 10:1+S (0.20/0.72g EPA/DHA per 2400 kcal/d)]. A mixed model analysis was conducted.

Results

Compared to the Control diet, the 10:1+S diet produced an increase in total cholesterol (9.9±9.9 mg/dl), apolipoprotein B (ApoB) (5.3±5.0 mg/dl) and ApoB:ApoA1 (0.06±0.04) in the context of a 17.8±11.5 mg/dl decrease in triglyceride levels (all p<0.05).

Conclusion

Consumption of a 10:1 n‐6 to n‐3 diet plus an algal‐oil supplement containing both EPA and DHA results in contrasting lipid changes; however, consumption of a different source of n‐3 fatty acids (flaxseed oil) yielded neutral effects.
A factorial design feeding study to evaluate the effects of α‐linolenic acid (ALA) versus eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on serum lipids in healthy adults
Authors: Sabaté Joan , Wien Michelle , Rajaram Sujatha , Haddad Ella
Published: June 2021

Background

Modern diets have n‐6 to n‐3 ratios greater than 10:1, whereas some ancient diets contained higher levels of α‐linolenic acid (ALA) and a ratio of ~2:1. The benefit of taking supplements of eicosapentaenoic (EPA) and docosahexaenoic acids (DHA) on serum lipids within these background diets is little known.

Aim and Methods

A factorial design approach was used to test the overall diet effect (10:1 vs. 2:1), supplement (S) effect (±EPA/DHA) and potential treatment interaction on serum lipids. A randomized cross‐over feeding trial (8‐week periods) in 24 healthy adults was conducted. Subjects consumed eucaloric diets [10:1 (Control), 2:1 (ALA; 6–7g/2400 kcal/d), 10:1+S (0.20/0.72g EPA/DHA per 2400 kcal/d), and, 2:1+S].

Results

A decrease in total cholesterol (TC) [7.7±3.3 mg/dl (P<0.01)] and apolipoprotein B (ApoB) [2.7±1.5 mg/dl (P=0.04)] was observed in changing from a 10:1 to a 2:1 diet. Taking EPA/DHA decreased triglycerides 7.6±5.5 mg/dl and increased TC (8.0±3.3 mg/dl), HDL (3.0±1.0 mg/dl), LDL (6.2±2.9 mg/dl), ApoB (4.7±1.6 mg/dl) and ApoB:ApoA1 (0.03±0.01)(all P<0.001). A synergistic effect was found for TC:HDL, which decreased more than expected (P=0.01).

Conclusion

The diet ratio and EPA/DHA supplement had distinct effects on serum lipids, and, synergistic effects occurred for TC:HDL, the clinical lipid parameter with the highest predictive value for cardiovascular risk.
Association of overweight and cognitive performance in Mexican children
Authors: Caamaño María del Carmen , García Olga Patricia , Ronquillo Dolores , García‐Vargas Gonzalo G , Rosado Jorge Luis
Published: June 2021

Prevalence of overweight among children has increased recently; its health and psychosocial consequences have raised attention. The objective of this study was to investigate the association of obesity and cognitive performance in school‐age Mexican children. 875 children (6 to 8 years) from 18 schools accepted to participate. Weight and height was measured, and 9 cognition tests were administered, involving mathematics, memory, attention, vocabulary and visual‐spatial skills. A fasting blood sample was taken to measure hemoglobin and plasma zinc concentration, and a socio‐economic questionnaire was administered to mothers. 26% had BMI for age percentile >85%. Results from a univariate analysis of variance adjusted for school, age, socioeconomic status, gender, mother education level, plasma zinc and hemoglobin showed a significant effect of overweight children in the Arithmetic Wisc‐RM test. Overweighed children had a lower score [6.19 (95%CI: 5.7–6.7)] than children with normal weight [6.8 (6.4–7.1)]. The remaining 8 tests did not show association. Considering a possible effect of overweight on cognitive performance, more research is needed to confirm this effect and the mechanism involved.
Qualitative examination of cultural influences on diet and physical activity patterns among Latino WIC families
Authors: Kim Loan Pham , Harrison Gail , Whaley Shannon , Mallo Nelly , Jenkins Eloise
Published: June 2021

Childhood obesity rates have risen sharply in the US in the past several decades, and at particular risk are immigrant Latino children who are twice as likely as African‐American or white children to be overweight. General consensus among researchers and practitioners is that dietary treatment of overweight in children alone is usually unsatisfactory. Prevention, beginning early in childhood through careful attention to both diet and physical activity and factors influencing these behaviors, is the only viable public health option. This qualitative study conducted: 1) 20 one‐on‐one interviews with WIC mothers of children 3–5 years of age, 2) 10 interviews with WIC para‐professional staff. Interviews were designed to elicit culturally relevant information to contribute to our understanding of the complex landscape in which childhood obesity exists by examining the physical environment of diet and physical activity behaviors, and the social environment in which cultural norms and beliefs influence perceptions, behaviors and practices. We will present salient elements, identified from this research, for developing effective childhood obesity prevention programs focusing on low‐income Latinos in California.

Grant Funding Source: AMERICAN HEART ASSOCIATION #09PRE2390123.
Feeding soy protein isolate (SPI) does not result in an estrogenic gene expression profile in the mammary of ovariectomized (OVX) female rats
Authors: Ronis Martin J , Singhal Rohit , Shankar Kartik , Badeaux Jamie , Badger Thomas M
Published: June 2021

Concerns of increased breast cancer risk in women consuming soy exist because of the perceived estrogenicity of soy isoflavones. Female Sprague‐Dawley rats (N = 20/group) were fed AIN‐93G diets with casein or SPI as the protein from PND30. On PND50 rats were OVX and 10/group infused s.c. with 5 μg/kg/d 17β‐estradiol (E2) to restore physiological levels. On PND64, mammary glands were collected and total mRNA isolated for microarray analysis. Array data were normalized using GeneSpring. Statistical analysis of genes expressed greater than 1.5‐fold revealed 651 genes regulated by E2 (P< 0.05) compared to 27 genes regulated by SPI with only 6 in common between the two treatments. A sub‐set of 164 E2‐regulated genes were further modulated by SPI feeding and 126 genes were only affected by the combination of SPI + E2. Data were confirmed by real time RT‐PCR and suggest that gene signatures of E2 and SPI have little overlap. SPI feeding did significantly modulate responses to E2. In most cases SPI antagonized E2 effects. This included ERβ‐specific genes such as Knsl2 and Top2a and the cell proliferation mediator cyclin D1. USDA CRIS 6251‐51000‐007‐03S.
Selenium compounds activate early barriers of tumorigenesis
Authors: Wu Min , Kang Mandy M , Schoene Norberta W , Cheng Wen‐Hsing
Published: June 2021

Selenium chemoprevention by apoptosis has been well studied, but it is not clear whether selenium can activate early barriers of tumorigenesis, namely senescence and DNA damage response. To address this issue, we treated normal and cancerous cells with a gradient concentration of sodium selenite, methylseleninic acid and methylselenocysteine for 48 hours, followed by a recovery of 1–7 days. Here we show that doses of the selenium compounds ≤LD50 can induce cellular senescence, as evidenced by the expression of senescence‐associated β‐galactosidase and 5‐bromo‐2‐deoxyuridine incorporation, in normal but not cancerous cells. In response to clastogens, ATM is rapidly activated, which in turn initiates a cascade of DNA damage response. We found that the ATM pathway is activated by the selenium compounds, and the kinase activity is required for the selenium‐induced senescence response. Pre‐treatment of the MRC‐5 cells with an antioxidant, N‐acetyl cysteine, prevents the Se‐induced ATM activation and senescence. Taken together, the results suggest a novel role of selenium in the activation of tumorigenesis barriers specific in non‐cancerous cells, whereby selenium induces an ATM‐dependent senescence response that depends on reactive oxygen species.

Grant Funding Source: University of maryland
Modified, extracted barley beta glucan(BBG) effectively lowers LDL‐Cholesterol despite low viscosity
Authors: Keenan Joseph Michael
Published: June 2021

Many studies have shown that foods rich in viscous fibers can lower LDL‐ C. This study compared the effect on blood lipids of a food and beverage fortified with unmodified BBG (HMW), average molecular weight of 1000 kDa, to the effect of the same food and beverage fortified with modified BBG (LMW), average molecular weight 50–400 kDa in persons with moderate dyslipidemia. Subjects(N=155) with LDL‐C levels between 130 and 190 mg/dl after a 4 week run in period on a “heart‐healthy” diet were randomized to 5 parallel treatment arms (5g/d HMW, 5g/d LMW, 3g/d HMW, 3g/d LMW or control). Over the six week treatment period subjects consumed one serving per day of a fortified cereal and one serving per day of a fortified beverage or control. Results: change from baseline in LDL‐C (5g HMW = − 22.5 mg/dl (−14.6%); 5g LMW = − 20.3mg/dl (−13.1%); 3g HMW = −14mg/dl (−9%); 3g LMW = − 13.4mg/dl (−9%). There was good compliance with all treatments with all subject groups consuming 94+% of servings and there were no drop outs or significant differences in side effects reported except for increased intestinal gas in the 5g HMW compared to control.
When a calorie isn't just a calorie: isocaloric, isonitrogenous diets containing different protein sources produce differential body composition outcomes in rats
Authors: Moulton Christopher , Norton Layne , Wilson Gabriel , Layman Donald K.
Published: June 2021

Peak activation of muscle protein synthesis and associated initiation factors is proportional to the leucine (LEU) content of a meal. Long‐term effects of LEU in complete meals on body composition remain controversial. This study evaluated the impact of two different protein sources fed in isocaloric, isonitrogenous meals on long term body composition and tissue weights. WHEAT (supplemented with lysine; 6.8% LEU) and WHEY (10.9% LEU) diets provided 16/54/30% of energy from protein/carbohydrate/fat. Male SD rats ~275g were fed 3 meals/d for 75d to mimic human meal patterns. Energy was restricted to ~80% of ad libitum intake to increase efficiency of energy utilization. After 11 wk, body composition was determined by DXA (n = 12), and muscles and fat pads were harvested and weighed. Body fat % was significantly lower in WHEY than WHEAT (9.7% vs 12.4%). Lean body mass was not different, but gastrocnemius weight was 6% higher in WHEY. Fat mass was 26% greater in WHEAT and epididymal fat weight was 18% higher. Using DXA values, WHEAT deposited 62% more energy, of which 55% was partitioned to fat and 44% to lean tissue, while WHEY partitioned 30% to fat and 70% to lean tissue. These data indicate that protein quality and specifically LEU content of proteins fed in isocaloric conditions can impact energy partitioning and body composition. Support: National Dairy Council and Egg Nutrition Center.