bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural Basis of Heme Acquisition from Human Hemoglobin by the Gram‐Positive Pathogen Streptococcus pyogenes
Authors: Macdonald Ramsay , Phillips Martin , Cascio Duilio , Collazo Michael , Clubb Robert T. 
Published: June 2021

Our research seeks to learn how Gram‐positive pathogens acquire iron from the human host, a key process required for bacterial pathogenesis and a potential drug target. In particular, the focus of our work is the mechanism of heme extraction from hemoglobin (Hb), the main source of iron in the human body. In an effort to decipher this process, we are using a combination of biochemical and biophysical methods including X‐ray crystallography, isothermal titration calorimetry (ITC), nuclear magnetic resonance (NMR), analytical ultra‐centrifugation (AUC), and heme transfer assays. Current efforts are devoted to studying this process in Streptococcus pyogenes (S. pyogenes) given its relevance as a human pathogen. We have recently characterized a novel Hb receptor from S. pyogenes ‐ the Streptococcal hemoprotein receptor (Shr). Shr appears to contain a similar domain architecture to the well‐characterized Hb receptors IsdH and IsdB found in Staphylococcus aureus. Unlike IsdH and IsdB, Shr mediates Hb binding through a domain of unknown function (DUF). Here we present the structure of this DUF domain in isolation and progress toward determining its structure in complex with Hb. The crystal structure of the DUF domain in isolation reveals a novel Hb‐binding domain structurally unrelated to Hb‐binding domains from other Gram‐positive pathogens. In addition, we have collected biochemical data on this domain suggesting that it slows the rate of heme release from Hb. We hypothesize that the DUF domain may slow the spontaneous process of heme release by Hb after erythrocyte lysis, allowing heme to be subsequently utilized downstream in the S. pyogenes heme acquisition pathway. This work is significant as it describes a novel mechanism of heme acquisition by a Gram‐positive pathogen. Future studies will be devoted to understanding the mechanism of heme extraction by the full‐length Shr protein.Support or Funding InformationThis work was supported by National Institutes of Health Grant AI52217 (to R.T.C.). R.M. was supported by a Cellular and Molecular Biology Training Grant (Ruth L. Kirschstein National Research Service Award GM007185). NMR equipment used in this research was purchased using funds from shared equipment grant NIH S10OD016336.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Ni(II) Uptake by Yersiniabactin, a Metallophore Produced by Uropathogenic E. coli
Authors: Robinson Anne E. , Lowe Jessica E. , Koh Eun‐Ik , Henderson Jeffrey P. 
Published: June 2021

Metal ions can play dual roles as nutrients and toxins in the interaction between bacteria and their environments. E. coli isolates associated with urinary tract infections (UTIs) deploy siderophores, small molecule chelators defined by their ability to competitively bind iron(III) and deliver it to the cell. Yersiniabactin (Ybt) is a virulence‐associated siderophore of uropathogenic E. coli (UPEC) and was recently appreciated to also bind copper during UTIs in humans, forming Cu(II)‐Ybt complexes. Copper binding by Ybt was found to protect E. coli from copper toxicity and also to mediate controlled copper import for nutritional purposes. We have termed this process nutritional passivation. Ni(II) is generally less abundant than copper but is also a nutrient for E. coli with the potential for toxicity. We show here that the Ybt system of UPEC engages in an analogous nutritional passivation activity with Ni(II). Ybt passivates Ni(II) ions, protecting against Ni(II) toxicity in vitro. We also observe that UPEC can use Ni(II)‐Ybt as a nutrient source for nickel. Using quantitative LC‐MS/MS and isotope labeling, we detect import of Ni(II)‐Ybt and dissociation of the nickel, providing a nickel source for cellular enzymes. The metal‐free Ybt is secreted back outside of the cell to bind other metal ions. These findings broaden the spectrum of Ybt activity, reinforcing its value to UPEC as a true metallophore, capable of binding and importing not only iron, but also copper and nickel.Support or Funding InformationJ.P.H. acknowledges National Institute of Diabetes and Digestive and Kidney Diseases grant R01DK099534. A.E.R. was supported by the Mr. and Mrs. Spencer T. Olin Fellowship for Women in Graduate Study.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Janus‐Faced Role of ATP1B4 Gene Co‐option in Mammalian Evolution
Authors: Modyanov Nikolai 
Published: June 2021

ATP1B4 genes represent a rare instance of orthologous vertebrate gene co‐option (evolutionary changes of functions of the genes, which are present in a single unambiguous copy in all known vertebrate genomes) that radically changed functions of the encoded BetaM proteins, which are the Na, K‐ATPase subunits in lower vertebrates. In placental mammals, BetaM proteins gained entirely different properties through changes in the structure of N‐terminal domains. As a result of these evolutionary alterations, eutherian BetaM completely lost its ancestral role and became the only currently known skeletal and atrial cardiac muscle‐specific protein of the inner nuclear membrane, where it functions as a regulator of gene expression. Expression of BetaM is the highest in myocytes during late fetal and early postnatal development and is also robustly induced in regenerating adult muscle.Evolutionarily acquired new functions and a unique pattern of expression of BetaM proteins suggest that those new physiological functions are essential, might be necessary for survival of placental mammals in natural conditions, and provide an evolutionary advantage.To characterize BetaM function directly in vivo, the Atp1b4 knockout mouse model was generated. We have shown that loss of BetaM results in significantly lower body size and weight, growth retardation and high mortality of Atp1b4 knockout neonates. Transcriptome analysis by mRNA sequencing of skeletal muscle from neonatal wild type and knockout littermates revealed strong down‐regulation of fast‐twitch and up‐regulation of slow‐twitch muscle genes, and broad changes in expression of genes regulating lipid metabolism. These results imply that BetaM plays an important role during a critical period of perinatal and neonatal development of placental mammals and its damage or malfunction can cause birth and growth defects in humans.Most importantly, our experiments revealed a somewhat unexpected and profound beneficial effect of Atp1b4 disruption on metabolic parameters in adult male mice. We have shown that Atp1b4 knockout males, which survived to adulthood, have a significantly lower percentage of body fat, exhibit enhanced metabolic rate and insulin sensitivity, and are resistant to high‐fat diet‐induced obesity. These robust changes in mouse metabolic parameters induced by Atp1b4 disruption clearly demonstrate that eutherian BetaM plays the important role in development of pathways regulating metabolism of adult mice.Finally, ablation of the evolutionarily acquired functions of Atp1b4 gene in mice is in fact a simulation of the alternative pathway of mammalian evolution.Support or Funding InformationThis work was supported by Department of Physiology & Pharmacology and Center for Diabetes and Endocrine Research, University of Toledo College of Medicine.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Inhibitory effect of diosmetin on lipolysis and inflammation in adipocyte‐macrophage co‐culture model
Authors: Lee Hana , Sung Jeehye , Lee Junsoo 
Published: June 2021

Obesity has become one of the most common metabolic syndromes and has come to pose a major worldwide threat to human health. Paracrine interaction between macrophages and adipocytes in obese tissue is thought to be a trigger of metabolic syndromes. Diosmetin is a flavone found in citrus fruits. Diosmetin has been shown to alleviate inflammatory cell infiltration and to repress the nuclear factor‐kappa B(NF‐κB) signaling pathway. However, not much is known about the anti‐inflammatory and anti‐lipolytic activities of diosmetin in co‐culture system of adipocytes and macrophages. The objective of this study was to evaluate the inhibitory effect of diosmetin on the inflammation and lipolysis in the interaction between adipocytes and macrophages. The secretion of inflammatory mediators such as nitric oxide, monocyte chemoattractant protein‐1, and tumor necrosis factor‐α increased in a co‐culture medium, however, diosmetin significantly decreased the inflammatory mediators. Diosmetin down‐regulated the expression of inducible nitric oxide synthase in co‐cultured macrophages and adipocytes. Diosmetin inhibited the phosphorylation of mitogen‐activated protein kinases and translation of NF‐κB. In addition, diosmetin suppressed the protein production of hormone sensitive lipase and fatty acid binding protein 4 and increased the mRNA expression of adiponectin in co‐cultured adipocytes. These results indicated that diosmetin inhibited inflammation and lipolysis in the crosstalk between adipocytes and macrophages and diosmetin‐containing foods could be used in dietary therapy for the prevention of obesity‐related metabolic diseases.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Role of oxidative stress and inflammatory cytokines in Type 2 Diabetes Mellitus patients with and without small intestinal bacterial overgrowth
Authors: Rana Satyavati , Malik Aastha , Morya Rajesh Kumar , Sharma Surendra Kumar , Bhadada Sanjay Kumar 
Published: June 2021

BackgroundIn type 2 diabetes mellitus (T2DM), insufficient insulin or resistance to insulin in body results in reduced uptake of glucose causing hyperglycemia. This may lead to oxidative stress and further may increase cytokine production. Inflammation may affect gut neural apparatus that may lead to gastrointestinal dysmotility which may amplify occurrence of small intestinal bacterial overgrowth in these patients.AimTo study role of oxidative stress, inflammatory cytokines, gut motility(orocecal transit time: OCTT) and small intestinal bacterial overgrowth (SIBO) in T2DM patientsMaterials and Methods150 T2DM patients and 150 age and sex matched healthy controls were enrolled. SIBO and OCTT were measured using noninvasive glucose and lactulose hydrogen breath tests respectively. Plasma levels of IL‐6, TNF‐α and IL‐10 were measured by ELISA. Oxidative stress (lipid per‐oxidation (LPO) and anti‐oxidant parameters such as reduced glutathione (GSH), Super‐oxide dismutase(SOD) and catalase were measured by standard methods.ResultsOut of 150 T2DM patients, 72 (48%) were males with Mean ± SEM age 56.7±0.74 years. IL‐6, TNF‐α and IL‐10 in T2DM patients were significantly higher(p<0.05) as compared to controls. LPO in T2DM patients was significantly increased(p<0.05) while GSH was significantly decreased(p<0.001). Moreover, SOD and Catalase were significantly higher as compared to controls. OCTT was delayed and SIBO was significantly higher in patients as compared to controls. Furthermore, SIBO +ve patients showed delayed OCTT and inflammatory cytokines were higher in SIBO +ve patients as compared to SIBO –ve patients. Also, LPO, SOD and Catalase were higher whereas GSH lower in SIBO +ve patients as compared to SIBO –ve patientsConclusionIn T2DM patients, oxidative stress would have caused inflammation in gut wall. leading to delayed OCTT and SIBO.Support or Funding InformationDepartment of Biotechnology, New Delhi, India vide no BT/PR8369/MED/30/996/2013This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Crystallization and Study of Dihydrofolate Reductases (DHFR) in Wuchereria bancrofti and Brugia malayi.
Authors: Lange Keith Richard , Janson Cheryl , Goodey Nina 
Published: June 2021

Lymphatic Filariasis, commonly regarded as Elephantiasis, is a vastly untreated parasitic disease primarily caused by the worms Wuchereria bancrofti and Brugia malayi which affects ~63 million people in 73 countries. Current drug treatments, such as diethylcarbamazine and ivermectin, are effective drug treatments when the host is initially infected; however, upon onset of limb swelling, these treatments fail to eradicate the parasites. Dihydrofolate Reductase (DHFR), a vital and ubiquitous enzyme that aids in DNA synthesis and folate metabolism, is a well‐established drug target and may result in a treatment option for many suffering from the disease. Selective inhibition of DHFR in both organisms may lead to progress in combating the disease and therefore aiding those who are infected. Currently, the lack of three‐dimensional understanding of both enzymes poses as an obstacle for selective inhibition. Crystallization and X‐Ray diffraction of these enzymes would elucidate their respective binding sites which will provide an understanding of how these enzymes function and thus, providing insight as to how to introduce inhibition. Once crystal structures of both enzymes are obtained with and without ligand bound, rational drug design can begin. Currently, both DHFR enzymes are being expressed and purified by Dr. Goodey's research lab and several inhibition studies have already been carried about; however, crystallization procedures have recently begun to ultimately provide a detailed model as to how the enzymes function within these organisms. In the future and as a result of this project, kinetic studies can then subsequently be carried out to test possible selective inhibitors.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Syndecan‐4 and PECAM‐1‐Dependent Cell Motility
Authors: Abraham Valsamma , Parambath Andrew , Murarka Monisha , Zoga Kristi , Saeed Danyall , Tran Thuongvu , Kumar Rahul , DeLisser Horace 
Published: June 2021

Ligand interactions between PECAM‐1 and heparan sulfate proteoglycans have been implicated in the ability of PECAM‐1 to promote cell motility by stimulating Cdc42 activation and the extension of filopodia. However, the endothelial proteoglycan(s), involved in these activities are undefined. We therefore investigated the potential involvement of syndecans (SDCs), a family of four cell surface heparan sulfate proteoglycans, in these PECAM‐1‐dependent processes. For these studies, we employed HUVEC and REN cells (an EC surrogate) expressing mouse PECAM‐1 (REN‐MP). For both cell types, we observed that while syndecan‐1 (SDC1) and syndecan‐4 (SDC4) are surface expressed, SDC4, but not SDC1, co‐immunoprecipitated with PECAM‐1. This PECAM‐1/SDC4 interaction was disrupted by targeting PECAM‐1‐dependent, heparan/glycosaminoglycan (GAG) ligand binding. Further, antibody‐ and/or siRNA‐mediated inhibition of SDC4 in REN‐MP cells inhibited PECAM‐1‐dependent, heparan/GAG heterophilic binding, cell motility, filopodia extension and Cdc42 activation. The targeting of SDC4 did not suppress the concentration of PECAM‐1 in the tips of filopodia, a process previously shown to be mediated by PECAM‐1‐PECAM‐1 homophilic, but not heterophilic, ligand binding. These data suggest that cis binding interactions between PECAM‐1 and SDC4 in the membrane of endothelial cells are involved in PECAM‐1‐dependent cell motility during angiogenesis.Support or Funding InformationVeterans Administration Merit AwardThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Intravenous Lipid Emulsion Induces Endocytosis in Human Coronary Artery Endothelial Cells by a CD36/Caveolin‐1 Pathway
Authors: McVey Natalie , Richman Michael , Struve Janine , Baumgardt Shelley , Weihrauch Dorothee 
Published: June 2021

IntroductionIntravenous lipid emulsion like Intralipid™ (ILP) are fatty emulsions commonly used in parenteral nutrition. Previous research has shown that they protect against myocardial ischemia/reperfusion injury (IR) in animal models through a mechanism involving activation of Akt/extracellular signal‐regulated kinase‐1/glycogen synthase kinase‐3β pathway ultimately leading to delayed mitochondrial permeability transition pore (mPTP) opening and the induction of a protective effect by ILP. They are also studied in connection with local anesthetic toxicity and mechanisms of scavenging anesthetics from the blood stream.HypothesisThe direct effect of ILP on endothelial cells has not been studied. Hence, the mechanisms by which ILP crosses the endothelium are not well understood especially the effects of ILP on human coronary artery endothelial cells (HCAEC). We hypothesize that uptake of ILP occurs through endocytosis in HCAECs by the formation of a CD36/caveolin‐1 cell membrane complex.MethodsILP in a 1% dilution was administered to HCAECs for 2 hours or control was left untreated. Western blots were conducted with anti‐CD36, caveolin‐1, dynamin‐2, src kinase‐1, eNOS, and phospho‐eNOS antibodies and equal loading of protein confirmed with beta‐actin. Additional cells were exposed to ILP, and then immunohistochemistry was performed, to visualize uptake of ILP into cells. This was accomplished by co‐labeling of lysosomal associated protein 3 CD63 and styryl peptide and lysosomal marker FM5‐95.ResultsThe association of CD36 with caveolin‐1 is increased after stimulation with ILP. The tyrosine kinase Src kinase‐1 acts to phosphorylate dynamin‐2, a GTPase responsible for separating the vesicle from the plasma membrane. ILP stimulation induced phosphorylation of Src kinase 1 and increase in expression of dynamin2. ILP induced increased phosphorylation and Hsp90 association of eNOS, leading to increased synthesis of nitric oxide. Furthermore, the association and expression of lysosomal markers CD63 and FM5‐95 are increased after ILP treatment compared to no treatment.Summary and ConclusionOur data suggest that administration of ILP to endothelial cells induces an endosomal pathway by formation of CD36/caveolin association which leads to enhanced endosome formation seen by increased lysosomal markers. Furthermore, we can report that stimulation of endothelial cells with ILP results in an increase of eNOS activity and increased NO synthesis which might be important for the cardioprotective abilities.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Induction of Lymphangiomas by Freund's Incomplete Adjuvant (FIA) in Fatty Acid Binding Protein (FABP)‐3, 5 and 7 Knock‐out Mice
Authors: Ezaki Taichi , Sagawa Hiromi , Tokuda Nobuko , Tokuda Kazuhiro , Yamashiro Chiemi , Kimura Kazuhiro , Owada Yuji 
Published: June 2021

IntroductionIn an FIA‐induced benign lymphangioma model (Mancardi et al., 1999), we have suggested a sequential transformation from peritoneal mesothelial cells to functional lymphatic vessels via fat storing tumor cells after the FIA stimulation (EB2009 & 2015). However, the actual mechanism of the tumorigenesis and cellular involvement have yet to be established. FABPs are known to be involved in the promotion of cellular uptake and transport of fatty acids and the targeting of them to specific metabolic pathways. The aim of this study is, therefore, to investigate the possible involvement of FABPs during the FIA‐induced tumor development using FABP KO mice.Materials & MethodsLymphangiomas were induced in C57BL/6 (B6) mice and FABP3, 5 and 7 KO mice by an intraperitoneal injection of FIA (0.2 ml emulsion). For histological analyses, tissue cryosections were made and immunostained with various antibodies against FABP3, 4, 5, 7, and various lymphatic markers, such as podoplanin (PDPN), LYVE‐1 and LA102.Results & ConclusionsAfter FIA injection, peritoneal mesothelial cells became tall in height losing their polarity and gradually formed stratified cell masses on the peritoneal surface in B6 mice. The tumors became honeycomb‐like lymphangiomas consisted of ring‐like fat storing cells with various sizes. Some fat storing cells fused with each other and gradually formed either tubular structures like lymphatic vessels or huge follicles. These cells were strongly positive for PDPN, F4/80 and FABP5, but negative for FABP4. The follicular structures mainly consisted of FABP7+ cells. Interestingly, only the functional lymphatic vessel‐like structures expressed LYVE‐1 and LA102. In FABP‐KO mice, there was no significant difference in the incidence of tumors as compared with normal B6 mice. However, tumors developed more vigorously in FABP7 KO mice than other KO strains. Among FABP KO mice, relatively smaller fat storing cells were seen in FABP3 KO mice, whereas follicular type structures were more commonly found in FABP5 KO mice. In contrast, the tumors in FABP7 KO mice showed less fat storing cells with more inflammatory and fibrous components. In conclusion, a close relationship between the extrinsic FIA metabolism and the lymphatic system may be suggested in this tumor model, although the actual role and biological significance of each FABP in the tumorigenesis remain to be further clarified.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Investigation of selective induction of Korean red ginseng extract on cytochrome P450 2D and 3A
Authors: Jeon Ju Mi , Cho Pil Joung , Jo Jung Jae , Shrestha Riya , Lee Sangkyu 
Published: June 2021

Ginseng (Panax ginseng Meyer) has been used as a traditional herbal drug in Asian countries. In this study, herb‐drug interaction (HDI) of Korean red ginseng (KRG) extract was investigated using in vitro and in vivo models. Male 5‐week‐old C54BL/6N mice were administered orally with KRG (0, 0.5, 1, and 2 g/kg) once a day for 2 and 4 weeks. The activities of 5 CYP enzymes were determined by monitoring the concentration of probes in blood by using cocktail assay. CYP2D‐catalyzed dextromethorphan O‐demethylation was found to be significantly induced after repeated administration of KRG. The AUCratio of probe for CYP2D decreased with the elevation of the dose and duration of KRG administration. Contrarily, AUCratio of probe for CYP3A increased on increasing the dose and duration of KRG administration. Similarly, CYP3A‐catalyzed midazolam 1′‐hydroxylation also increased in dose‐dependent manner in vitro. Herein, we suggested the possibility of KRG‐induced drug interaction upon continuous administration for 2 – 4 weeks.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.