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Bacterial Energetic Requirements for Helicobacter pylori Cag Type IV Secretion System-Dependent Alterations in Gastric Epithelial Cells.
Lin AS, Dooyema SDR, Frick-Cheng AE, Harvey ML, Suarez G, Loh JT, McDonald WH, McClain MS, Peek RM, Cover TL
(2020) Infect Immun 88:
MeSH Terms: Antigens, Bacterial, Bacterial Proteins, Biological Transport, DNA, Bacterial, Epithelial Cells, Helicobacter pylori, Humans, Interleukin-8, Lipopolysaccharides, NF-kappa B, Peptidoglycan, Toll-Like Receptor 9, Type IV Secretion Systems, Virulence Factors
Show Abstract · Added March 3, 2020
colonizes the stomach in about half of the world's population. strains containing the pathogenicity island ( PAI) are associated with a higher risk of gastric adenocarcinoma or peptic ulcer disease than PAI-negative strains. The PAI encodes a type IV secretion system (T4SS) that mediates delivery of the CagA effector protein as well as nonprotein bacterial constituents into gastric epithelial cells. -induced nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation and interleukin-8 (IL-8) secretion are attributed to T4SS-dependent delivery of lipopolysaccharide metabolites and peptidoglycan into host cells, and Toll-like receptor 9 (TLR9) activation is attributed to delivery of bacterial DNA. In this study, we analyzed the bacterial energetic requirements associated with these cellular alterations. Mutant strains lacking Cagα, Cagβ, or CagE (putative ATPases corresponding to VirB11, VirD4, and VirB4 in prototypical T4SSs) were capable of T4SS core complex assembly but defective in CagA translocation into host cells. Thus, the three Cag ATPases are not functionally redundant. Cagα and CagE were required for -induced NF-κB activation, IL-8 secretion, and TLR9 activation, but Cagβ was dispensable for these responses. We identified putative ATP-binding motifs (Walker-A and Walker-B) in each of the ATPases and generated mutant strains in which these motifs were altered. Each of the Walker box mutant strains exhibited properties identical to those of the corresponding deletion mutant strains. These data suggest that Cag T4SS-dependent delivery of nonprotein bacterial constituents into host cells occurs through mechanisms different from those used for recruitment and delivery of CagA into host cells.
Copyright © 2020 American Society for Microbiology.
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Histone deacetylase 3 controls a transcriptional network required for B cell maturation.
Stengel KR, Bhaskara S, Wang J, Liu Q, Ellis JD, Sampathi S, Hiebert SW
(2019) Nucleic Acids Res 47: 10612-10627
MeSH Terms: Animals, Antigens, CD19, B-Lymphocytes, Base Sequence, Cell Differentiation, Gene Expression Regulation, Gene Regulatory Networks, Histone Deacetylase Inhibitors, Histone Deacetylases, Lipopolysaccharides, Lymphocyte Activation, Mice, Inbred C57BL, Plasma Cells, Positive Regulatory Domain I-Binding Factor 1, Proto-Oncogene Proteins c-bcl-6, Repressor Proteins, Transcription, Genetic, Up-Regulation
Show Abstract · Added October 25, 2019
Histone deacetylase 3 (Hdac3) is a target of the FDA approved HDAC inhibitors, which are used for the treatment of lymphoid malignancies. Here, we used Cd19-Cre to conditionally delete Hdac3 to define its role in germinal center B cells, which represent the cell of origin for many B cell malignancies. Cd19-Cre-Hdac3-/- mice showed impaired germinal center formation along with a defect in plasmablast production. Analysis of Hdac3-/- germinal centers revealed a reduction in dark zone centroblasts and accumulation of light zone centrocytes. RNA-seq revealed a significant correlation between genes up-regulated upon Hdac3 loss and those up-regulated in Foxo1-deleted germinal center B cells, even though Foxo1 typically activates transcription. Therefore, to determine whether gene expression changes observed in Hdac3-/- germinal centers were a result of direct effects of Hdac3 deacetylase activity, we used an HDAC3 selective inhibitor and examined nascent transcription in germinal center-derived cell lines. Transcriptional changes upon HDAC3 inhibition were enriched for light zone gene signatures as observed in germinal centers. Further comparison of PRO-seq data with ChIP-seq/exo data for BCL6, SMRT, FOXO1 and H3K27ac identified direct targets of HDAC3 function including CD86, CD83 and CXCR5 that are likely responsible for driving the light zone phenotype observed in vivo.
© The Author(s) 2019. Published by Oxford University Press on behalf of Nucleic Acids Research.
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18 MeSH Terms
Fetal exposure to maternal inflammation interrupts murine intestinal development and increases susceptibility to neonatal intestinal injury.
Elgin TG, Fricke EM, Gong H, Reese J, Mills DA, Kalantera KM, Underwood MA, McElroy SJ
(2019) Dis Model Mech 12:
MeSH Terms: Animals, Animals, Newborn, Biomarkers, Cecum, Cytokines, Disease Susceptibility, Female, Fetus, Goblet Cells, Inflammation, Intestine, Small, Lipopolysaccharides, Mice, Inbred C57BL, Microbiota, Paneth Cells, Pregnancy
Show Abstract · Added July 28, 2020
Fetal exposure to chorioamnionitis can impact the outcomes of the developing fetus both at the time of birth and in the subsequent neonatal period. Infants exposed to chorioamnionitis have a higher incidence of gastrointestinal (GI) pathology, including necrotizing enterocolitis (NEC); however, the mechanism remains undefined. To simulate the fetal exposure to maternal inflammation (FEMI) induced by chorioamnionitis, pregnant mice (C57BL/6J, , or ) were injected intraperitoneally on embryonic day (E)15.5 with lipopolysaccharide (LPS; 100 µg/kg body weight). Pups were delivered at term, and reared to postnatal day (P)0, P7, P14, P28 or P56. Serum and intestinal tissue samples were collected to quantify growth, inflammatory markers, histological intestinal injury, and goblet and Paneth cells. To determine whether FEMI increased subsequent susceptibility to intestinal injury, a secondary dose of LPS (100 µg/kg body weight) was given on P5, prior to tissue harvesting on P7. FEMI had no effect on growth of the offspring or their small intestine. FEMI significantly decreased both goblet and Paneth cell numbers while simultaneously increasing serum levels of IL-1β, IL-10, KC/GRO (CXCL1 and CXCL2), TNF and IL-6. These alterations were IL-6 dependent and, importantly, increased susceptibility to LPS-induced intestinal injury later in life. Our data show that FEMI impairs normal intestinal development by decreasing components of innate immunity and simultaneously increasing markers of inflammation. These changes increase susceptibility to intestinal injury later in life and provide novel mechanistic data to potentially explain why preterm infants exposed to chorioamnionitis prior to birth have a higher incidence of NEC and other GI disorders.
© 2019. Published by The Company of Biologists Ltd.
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Rapid changes in the microvascular circulation of skeletal muscle impair insulin delivery during sepsis.
Mignemi NA, McClatchey PM, Kilchrist KV, Williams IM, Millis BA, Syring KE, Duvall CL, Wasserman DH, McGuinness OP
(2019) Am J Physiol Endocrinol Metab 316: E1012-E1023
MeSH Terms: Animals, Capillaries, Capillary Permeability, Disease Models, Animal, Echocardiography, Hyperglycemia, Insulin, Insulin Resistance, Lipopolysaccharides, Mice, Microcirculation, Microvessels, Muscle Fibers, Skeletal, Muscle, Skeletal, Sepsis
Show Abstract · Added March 26, 2019
Sepsis costs the healthcare system $23 billion annually and has a mortality rate between 10 and 40%. An early indication of sepsis is the onset of hyperglycemia, which is the result of sepsis-induced insulin resistance in skeletal muscle. Previous investigations have focused on events in the myocyte (e.g., insulin signaling and glucose transport and subsequent metabolism) as the causes for this insulin-resistant state. However, the delivery of insulin to the skeletal muscle is also an important determinant of insulin action. Skeletal muscle microvascular blood flow, which delivers the insulin to the muscle, is known to be decreased during sepsis. Here we test whether the reduced capillary blood flow to skeletal muscle belies the sepsis-induced insulin resistance by reducing insulin delivery to the myocyte. We hypothesize that decreased capillary flow and consequent decrease in insulin delivery is an early event that precedes gross cardiovascular alterations seen with sepsis. This hypothesis was examined in mice treated with either lipopolysaccharide (LPS) or polymicrobial sepsis followed by intravital microscopy of the skeletal muscle microcirculation. We calculated insulin delivery to the myocyte using two independent methods and found that LPS and sepsis rapidly reduce insulin delivery to the skeletal muscle by ~50%; this was driven by decreases in capillary flow velocity and the number of perfused capillaries. Furthermore, the changes in skeletal muscle microcirculation occur before changes in both cardiac output and arterial blood pressure. These data suggest that a rapid reduction in skeletal muscle insulin delivery contributes to the induction of insulin resistance during sepsis.
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15 MeSH Terms
Lipopolysaccharide Induced Opening of the Blood Brain Barrier on Aging 5XFAD Mouse Model.
Barton SM, Janve VA, McClure R, Anderson A, Matsubara JA, Gore JC, Pham W
(2019) J Alzheimers Dis 67: 503-513
MeSH Terms: Aging, Alzheimer Disease, Amyloid beta-Peptides, Animals, Benzothiazoles, Biological Availability, Blood-Brain Barrier, Ferric Compounds, Humans, Inflammation, Lipopolysaccharides, Mice, Mice, Inbred C57BL, Mice, Transgenic, Nanoparticles, Permeability, Plaque, Amyloid
Show Abstract · Added March 26, 2019
The development of neurotherapeutics for many neurodegenerative diseases has largely been hindered by limited pharmacologic penetration across the blood-brain barrier (BBB). Previous attempts to target and clear amyloid-β (Aβ) plaques, a key mediator of neurodegenerative changes in Alzheimer's disease (AD), have had limited clinical success due to low bioavailability in the brain because of the BBB. Here we test the effects of inducing an inflammatory response to disrupt the BBB in the 5XFAD transgenic mouse model of AD. Lipopolysaccharide (LPS), a bacterial endotoxin recognized by the innate immune system, was injected at varying doses. 24 hours later, mice were injected with either thioflavin S, a fluorescent Aβ-binding small molecule or 30 nm superparamagnetic iron oxide (SPIO) nanoparticles, both of which are unable to penetrate the BBB under normal physiologic conditions. Our results showed that when pretreated with 3.0 mg/kg LPS, thioflavin S can be found in the brain bound to Aβ plaques in aged 5XFAD transgenic mice. Following the same LPS pretreatment, SPIO nanoparticles could also be found in the brain. However, when done on wild type or young 5XFAD mice, limited SPIO was detected. Our results suggest that the BBB in aged 5XFAD mouse model is susceptible to increased permeability mediated by LPS, allowing for improved delivery of the small molecule thioflavin S to target Aβ plaques and SPIO nanoparticles, which are significantly larger than antibodies used in clinical trials for immunotherapy of AD. Although this approach demonstrated efficacy for improved delivery to the brain, LPS treatment resulted in significant weight loss even at low doses, resulting from the induced inflammatory response. These findings suggest inducing inflammation can improve delivery of small and large materials to the brain for improved therapeutic or diagnostic efficacy. However, this approach must be balanced with the risks of systemic inflammation.
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17 MeSH Terms
Omega-3 polyunsaturated fatty acids attenuate inflammatory activation and alter differentiation in human adipocytes.
Ferguson JF, Roberts-Lee K, Borcea C, Smith HM, Midgette Y, Shah R
(2019) J Nutr Biochem 64: 45-49
MeSH Terms: Adipocytes, Cell Differentiation, Cells, Cultured, Coculture Techniques, Docosahexaenoic Acids, Eicosapentaenoic Acid, Fatty Acids, Omega-3, Humans, Inflammation, Leukocytes, Lipid Droplets, Lipopolysaccharides, Macrophages, Obesity
Show Abstract · Added April 2, 2019
BACKGROUND - Omega-3 polyunsaturated fatty acids, specifically the fish-oil-derived eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been proposed as inflammation-resolving agents via their effects on adipose tissue.
OBJECTIVE - We proposed to determine the effects of EPA and DHA on human adipocyte differentiation and inflammatory activation in vitro.
METHODS - Primary human subcutaneous adipocytes from lean and obese subjects were treated with 100 μM EPA and/or DHA throughout differentiation (differentiation studies) or for 72 h postdifferentiation (inflammatory studies). THP-1 monocytes were added to adipocyte wells for co-culture experiments. Subcutaneous and visceral adipose explants from obese subjects were treated for 72 h with EPA and DHA. Oil Red O staining was performed on live cells. Cells were collected for mRNA analysis by quantitative polymerase chain reaction, and media were collected for protein quantification by enzyme-linked immunosorbent assay.
RESULTS - Incubation with EPA and/or DHA attenuated inflammatory response to lipopolysaccharide (LPS) and monocyte co-culture with reduction in post-LPS mRNA expression and protein levels of IL6, CCL2 and CX3CL1. Expression of inflammatory genes was also reduced in the endogenous inflammatory response in obese adipose. Both DHA and EPA reduced lipid droplet formation and lipogenic gene expression without alteration in expression of adipogenic genes or adiponectin secretion.
CONCLUSIONS - EPA and DHA attenuate inflammatory activation of in vitro human adipocytes and reduce lipogenesis.
Copyright © 2018 Elsevier Inc. All rights reserved.
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14 MeSH Terms
Detection of Cyclooxygenase-2-Derived Oxygenation Products of the Endogenous Cannabinoid 2-Arachidonoylglycerol in Mouse Brain.
Morgan AJ, Kingsley PJ, Mitchener MM, Altemus M, Patrick TA, Gaulden AD, Marnett LJ, Patel S
(2018) ACS Chem Neurosci 9: 1552-1559
MeSH Terms: Animals, Arachidonic Acids, Brain, Cyclooxygenase 2, Cyclooxygenase 2 Inhibitors, Endocannabinoids, Esters, Female, Glycerides, Inflammation, Lipopolysaccharides, Male, Mice, Inbred C57BL, Mice, Transgenic, Monoacylglycerol Lipases, Neurons, Oxidation-Reduction, Prostaglandins
Show Abstract · Added October 8, 2018
Cyclooxygenase-2 (COX-2) catalyzes the formation of prostaglandins, which are involved in immune regulation, vascular function, and synaptic signaling. COX-2 also inactivates the endogenous cannabinoid (eCB) 2-arachidonoylglycerol (2-AG) via oxygenation of its arachidonic acid backbone to form a variety of prostaglandin glyceryl esters (PG-Gs). Although this oxygenation reaction is readily observed in vitro and in intact cells, detection of COX-2-derived 2-AG oxygenation products has not been previously reported in neuronal tissue. Here we show that 2-AG is metabolized in the brain of transgenic COX-2-overexpressing mice and mice treated with lipopolysaccharide to form multiple species of PG-Gs that are detectable only when monoacylglycerol lipase is concomitantly blocked. Formation of these PG-Gs is prevented by acute pharmacological inhibition of COX-2. These data provide evidence that neuronal COX-2 is capable of oxygenating 2-AG to form a variety PG-Gs in vivo and support further investigation of the physiological functions of PG-Gs.
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18 MeSH Terms
Epithelial Heparan Sulfate Contributes to Alveolar Barrier Function and Is Shed during Lung Injury.
Haeger SM, Liu X, Han X, McNeil JB, Oshima K, McMurtry SA, Yang Y, Ouyang Y, Zhang F, Nozik-Grayck E, Zemans RL, Tuder RM, Bastarache JA, Linhardt RJ, Schmidt EP
(2018) Am J Respir Cell Mol Biol 59: 363-374
MeSH Terms: Animals, Capillary Permeability, Endothelium, Vascular, Glycocalyx, Heparitin Sulfate, Lipopolysaccharides, Lung Injury, Mice, Respiratory Distress Syndrome, Syndecans
Show Abstract · Added May 31, 2018
The lung epithelial glycocalyx is a carbohydrate-enriched layer lining the pulmonary epithelial surface. Although epithelial glycocalyx visualization has been reported, its composition and function remain unknown. Using immunofluorescence and mass spectrometry, we identified heparan sulfate (HS) and chondroitin sulfate within the lung epithelial glycocalyx. In vivo selective enzymatic degradation of epithelial HS, but not chondroitin sulfate, increased lung permeability. Using mass spectrometry and gel electrophoresis approaches to determine the fate of epithelial HS during lung injury, we detected shedding of 20 saccharide-long or greater HS into BAL fluid in intratracheal LPS-treated mice. Furthermore, airspace HS in clinical samples from patients with acute respiratory distress syndrome correlated with indices of alveolar permeability, reflecting the clinical relevance of these findings. The length of HS shed during intratracheal LPS-induced injury (≥20 saccharides) suggests cleavage of the proteoglycan anchoring HS to the epithelial surface, rather than cleavage of HS itself. We used pharmacologic and transgenic animal approaches to determine that matrix metalloproteinases partially mediate HS shedding during intratracheal LPS-induced lung injury. Although there was a trend toward decreased alveolar permeability after treatment with the matrix metalloproteinase inhibitor, doxycycline, this did not reach statistical significance. These studies suggest that epithelial HS contributes to the lung epithelial barrier and its degradation is sufficient to increase lung permeability. The partial reduction of HS shedding achieved with doxycycline is not sufficient to rescue epithelial barrier function during intratracheal LPS-induced lung injury; however, whether complete attenuation of HS shedding is sufficient to rescue epithelial barrier function remains unknown.
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Single-Cell Mass Spectrometry Reveals Changes in Lipid and Metabolite Expression in RAW 264.7 Cells upon Lipopolysaccharide Stimulation.
Yang B, Patterson NH, Tsui T, Caprioli RM, Norris JL
(2018) J Am Soc Mass Spectrom 29: 1012-1020
MeSH Terms: Animals, Lipids, Lipopolysaccharides, Macrophages, Mice, RAW 264.7 Cells, Single-Cell Analysis, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
Show Abstract · Added March 22, 2018
It has been widely recognized that individual cells that exist within a large population of cells, even if they are genetically identical, can have divergent molecular makeups resulting from a variety of factors, including local environmental factors and stochastic processes within each cell. Presently, numerous approaches have been described that permit the resolution of these single-cell expression differences for RNA and protein; however, relatively few techniques exist for the study of lipids and metabolites in this manner. This study presents a methodology for the analysis of metabolite and lipid expression at the level of a single cell through the use of imaging mass spectrometry on a high-performance Fourier transform ion cyclotron resonance mass spectrometer. This report provides a detailed description of the overall experimental approach, including sample preparation as well as the data acquisition and analysis strategy for single cells. Applying this approach to the study of cultured RAW264.7 cells, we demonstrate that this method can be used to study the variation in molecular expression with cell populations and is sensitive to alterations in that expression that occurs upon lipopolysaccharide stimulation. Graphical Abstract.
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8 MeSH Terms
Monitoring uterine contractility in mice using a transcervical intrauterine pressure catheter.
Robuck MF, O'Brien CM, Knapp KM, Shay SD, West JD, Newton JM, Slaughter JC, Paria BC, Reese J, Herington JL
(2018) Reproduction 155: 447-456
MeSH Terms: Animals, Catheters, Disease Models, Animal, Female, Lipopolysaccharides, Mice, Mifepristone, Parturition, Pregnancy, Premature Birth, Pressure, Uterine Contraction
Show Abstract · Added March 31, 2018
In mouse models used to study parturition or pre-clinical therapeutic testing, measurement of uterine contractions is limited to either isometric tension or operative intrauterine pressure (IUP). The goal of this study was to: (1) develop a method for transcervical insertion of a pressure catheter to measure intrauterine contractile pressure during mouse pregnancy, (2) determine whether this method can be utilized numerous times in a single mouse pregnancy without affecting the timing of delivery or fetal outcome and (3) compare the contractile activity between mouse models of term and preterm labor (PTL). Visualization of the cervix allowed intrauterine pressure catheter (IUPC) placement into anesthetized pregnant mice (plug = day 1, delivery = day 19.5). The amplitude, frequency, duration and area under the curve (AUC) of IUP was lowest on days 16-18, increased significantly ( < 0.05) on the morning of day 19 and reached maximal levels during by the afternoon of day 19 and into the intrapartum period. An AUC threshold of 2.77 mmHg discriminated between inactive labor (day 19 am) and active labor (day 19 pm and intrapartum period). Mice examined on a single vs every experimental timepoint did not have significantly different IUP, timing of delivery, offspring number or fetal/neonatal weight. The IUP was significantly greater in LPS-treated and RU486-treated mouse models of PTL compared to time-matched vehicle control mice. Intrapartum IUP was not significantly different between term and preterm mice. We conclude that utilization of a transcervical IUPC allows sensitive assessment of uterine contractile activity and labor progression in mouse models without the need for operative approaches.
© 2018 Society for Reproduction and Fertility.
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12 MeSH Terms