Immunology of Infectious Disease Commons^™

Novel And Predominant Pathogen Responsible For The Enterovirus-Associated Encephalitis In Eastern China, Lei Zhang, Jie Yan, David M. Ojcius, Huakun Lv, Ziping Miao, Yin Chen, Yanjun Zhang, Jvying Yan

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Enteroviruses (EV) have been increasingly identified as the causative agent for unknown etiological encephalitis in many parts of the world, but the long period surveillance for enterovirus-associated encephalitis (EAE) was not reported in China. From 2002-2012 in Zhejiang, Coxsackieviruses A9, B1, B2, B3, B4, B5; and echoviruses 3, 4, 6, 9, 14, 25, 30 were detected from the unknown etiological encephalitis cases, with coxsackievirus B4 been identified here for the first time. From 2002-2004 and 2010-2012, echovirus 30 was found to be the periodically predominant serotype for in the EAE. The molecular typing results showed that all the EV isolates …

Membrane Vesicles Nucleate Mineralo-Organic Nanoparticles And Induce Carbonate Apatite Precipitation In Human Body Fluids, Cheng-Yeu Wu, Jan Martel, Wei-Yun Cheng, Chao-Chih He, David M. Ojcius, John Ding-E. Young

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Recent studies indicate that membrane vesicles (MVs) secreted by various cells are associated with human diseases, including arthritis, atherosclerosis, cancer, and chronic kidney disease. The possibility that MVs may induce the formation of mineralo-organic nanoparticles (NPs) and ectopic calcification has not been investigated so far. Here, we isolated MVs ranging in size between 20 and 400 nm from human serum and FBS using ultracentrifugation and sucrose gradient centrifugation. The MV preparations consisted of phospholipid-bound vesicles containing the serum proteins albumin, fetuin-A, and apolipoprotein A1; the mineralization-associated enzyme alkaline phosphatase; and the exosome proteins TNFR1 and CD63. Notably, we observed that …

Identification Of Leptospira Interrogans Phospholipase C As A Novel Virulence Factor Responsible For Intracellular Free Calcium Ion Elevation During Macrophage Death, Jing-Fang Zhao, Hong-Hu Chen, David M. Ojcius, Xin Zhao, Dexter Sun, Yu-Mei Ge, Lin-Li Zheng, Xu'ai Lin, Lan-Juan Li, Jie Yan

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Background: Leptospira-induced macrophage death has been confirmed to play a crucial role in pathogenesis of leptospirosis, a worldwide zoonotic infectious disease. Intracellular free Ca²⁺ concentration ([Ca²⁺]i) elevation induced by infection can cause cell death, but [Ca²⁺]i changes and high [Ca²⁺]i-induced death of macrophages due to infection of Leptospira have not been previously reported.

Methodology/Principal Findings: We first used a Ca²⁺-specific fluorescence probe to confirm that the infection of L. interrogans strain Lai triggered a significant increase of [Ca²⁺]i in mouse J774A.1 or human THP-1 macrophages. Laser confocal microscopic examination …

Role Of Branched-Chain Amino Acid Transporters In Staphylococcus Aureus Virulence, Sameha Omer

Electronic Thesis and Dissertation Repository

Branched-chain amino acids (BCAAs) act as effector molecules that signal a global transcriptional regulator, CodY, to regulate virulence factors in nutrient depleted environments. Staphylococcus aureus contains three putative BCAA transporters (BrnQ1, BrnQ2, BrnQ3) whose role in BCAA uptake is unknown. We hypothesize that BrnQ transporters are involved in BCAA uptake and contribute to virulence in S. aureus by modulating CodY activity. Results from radioactive uptake assays indicate that BrnQ1 is the predominant BrnQ transporter of isoleucine, valine and leucine. Meanwhile, BrnQ2 is more specific for isoleucine. Furthermore, only the lack of BrnQ1 hinders growth of S. aureus in chemically-defined media …

P2x4 Assembles With P2x7 And Pannexin-1 In Gingival Epithelial Cells And Modulates Reactive Oxygen Species Production And Inflammasome Activation, Shu-Chen Hung, Chul Hee Choi, Najwane Said-Sadier, Larry Johnson, Kalina Rosenova Atanasova, Hanen Sellami, Özlem Yilmaz, David M. Ojcius

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We have previously reported that Porphyromonas gingivalis infection of gingival epithelial cells (GEC) requires an exogenous danger signal such as ATP to activate an inflammasome and caspase-1, thereby inducing secretion of interleukin (IL)-1β. Stimulation with extracellular ATP also stimulates production of reactive oxygen species (ROS) in GEC. However, the mechanism by which ROS is generated in response to ATP, and the role that different purinergic receptors may play in inflammasome activation, is still unclear. In this study, we revealed that the purinergic receptor P2X₄ is assembled with the receptor P2X₇ and its associated pore, pannexin-1. ATP induces ROS …

Human Adenovirus E1a Binds And Retasks Cellular Hbre1, Blocking Interferon Signalling And Activating Virus Early Gene Transcription, Gregory J. Fonseca

Electronic Thesis and Dissertation Repository

Upon infection, human adenovirus (HAdV) must block interferon signaling and activate the expression of its early genes to reprogram the cellular environment to support virus replication. During the initial phase of infection, these processes are orchestrated by the first HAdV gene expressed during infection, early region 1A (E1A). E1A binds and appropriates components of the cellular transcriptional machinery to modulate cellular gene transcription and activate viral early genes transcription. We have identified hBre1/RNF20 as a novel target of E1A. hBre1 is an E3 ubiquitin ligase which acts with the Ube2b E2 conjugase and accessory factors RNF40 and WAC1 to monoubiquitinate …

Cellular Adaptation Of Macrophages To Anthrax Lethal Toxin-Induced Pyroptosis Via Epigenetic Mechanisms, Chae Young Han

Electronic Thesis and Dissertation Repository

Cellular adaptation to microbial stresses has been demonstrated in several cell types. Macrophages (MФ) are sentinel immune cells fending off invading microbes. Anthrax lethal toxin (LeTx) is a key virulence factor released by Bacillus anthracis that causes rapid cell death, pyroptosis. A small number of RAW246.7 macrophages (~4%) exposed to a non-lethal dose of LeTx become resistant to LeTx-induced pyroptosis for ~ 4 weeks, termed “toxin-induced resistance (TIR)”. Here, I showed that high levels of DNA methyl transferase1 (DNMT1) expression were maintained although global genomic methylation levels were not high in TIR. TIR cells treated with the DNMT inhibitor 5-azacitidine …

Hirsutella Sinensis Mycelium Suppresses Interleukin-1b And Interleukin-18 Secretion By Inhibiting Both Canonical And Non-Canonical Inflammasomes, Tsung-Teng Huang, Kowit-Yu Chong, David M. Ojcius, Yi-Hui Wu, Yun-Fei Ko, Cheng-Yeu Wu, Jan Martel, Chia-Chen Lu, Hsin-Chih Lai, John Ding-E. Young

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Cordyceps sinensis is a medicinal mushroom used for centuries in Asian countries as a health supplement and tonic. Hirsutella sinensis—the anamorphic, mycelial form of C. sinensis—possesses similar properties, and is increasingly used as a health supplement. Recently, C. sinensis extracts were shown to inhibit the production of the pro-inflammatory cytokine IL-1β in lipopolysaccharide-treated macrophages. However, the molecular mechanism underlying this process has remained unclear. In addition, whether H. sinensis mycelium (HSM) extracts also inhibit the production of IL-1β has not been investigated. In the present study, the HSM extract suppresses IL-1β and IL-18 secretion, and ATP-induced activation of caspase-1. Notably, …

Wallace H. Coulter: Decades Of Invention And Discovery, Joseph Robinson

Joseph P Robinson

Only a few inventors can be said to have made as great an impact on mankind as Wallace Coulter. His inquisitive mind and ability to see well beyond what existed served him well for 40 years of inventing. So many of the fundamental tools that exist today in the area of hematology were derived from or driven by Coulter's inventions that he could be called the most technological innovator in the field of modern hematology. In achieving these discoveries Wallace Coulter was clearly capable of visualizing future opportunities that few others recognized. His vision was combined with an uncanny ability …