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Justin P Ingram, Igor E Brodsky, Siddharth Balachandran
Salmonella enterica is a facultative intracellular bacterium that is the leading cause of food borne illnesses in humans. The cytokine IFN-γ has well-established antibacterial properties against Salmonella and other intracellular microbes, for example its capacity to activate macrophages, promote phagocytosis, and destroy phagocytosed microbes by free radical-driven toxification of phagosomes. But IFN-γ induces the expression of hundreds of uncharacterized genes, suggesting that this cytokine deploys additional antimicrobial strategies that await discovery...
October 20, 2016: Cytokine
Jin Kyung Kim, Hye-Mi Lee, Ki-Sun Park, Dong-Min Shin, Tae Sung Kim, Yi Sak Kim, Hyun-Woo Suh, Soo Yeon Kim, In Soo Kim, Jin-Man Kim, Ji-Woong Son, Kyung Mok Sohn, Sung Soo Jung, Chaeuk Chung, Sang-Bae Han, Chul-Su Yang, Eun-Kyeong Jo
Autophagy is an important antimicrobial effector process that defends against Mycobacterium tuberculosis (Mtb), the human pathogen causing tuberculosis (TB). MicroRNAs (miRNAs), endogenous noncoding RNAs, are involved in various biological functions and act as post-transcriptional regulators to target mRNAs. The process by which miRNAs affect antibacterial autophagy and host defense mechanisms against Mtb infections in human monocytes and macrophages is largely uncharacterized. In this study, we show that Mtb significantly induces the expression of MIR144*/hsa-miR-144-5p, which targets the 3'-untranslated region of DRAM2 (DNA damage regulated autophagy modulator 2) in human monocytes and macrophages...
October 20, 2016: Autophagy
Erik Richter, Manuela Harms, Katharina Ventz, Rolf Nölker, Martin J Fraunholz, Jörg Mostertz, Falko Hochgräfe
Internalization of Staphylococcus aureus by non-professional phagocytic cells is a major suspected cause of persistent and difficult-to-treat infections, including pneumonia. In this study, we established an infection model with 16HBE14o- human bronchial epithelial cells and demonstrated internalization, escape from phagosomal clearance and intracellular replication of S. aureus HG001 within the first four hours post-infection. We used quantitative phosphoproteomics to identify characteristic signaling networks in the host at different infection stages...
October 20, 2016: Journal of Proteome Research
Aníbal M Reyes, Diego S Vazquez, Ari Zeida, Martín Hugo, M Dolores Piñeyro, María Inés De Armas, Darío Estrin, Rafael Radi, Javier Santos, Madia Trujillo
Mycobacterium tuberculosis (M. tuberculosis) is the intracellular bacterium responsible for tuberculosis disease (TD). Inside the phagosomes of activated macrophages, M. tuberculosis is exposed to cytotoxic hydroperoxides such as hydrogen peroxide, fatty acid hydroperoxides and peroxynitrite. Thus, the characterization of the bacterial antioxidant systems could facilitate novel drug developments. In this work, we characterized the product of the gene Rv1608c from M. tuberculosis, which according to sequence homology had been annotated as a putative peroxiredoxin of the peroxiredoxin Q subfamily (PrxQ B from M...
October 14, 2016: Free Radical Biology & Medicine
Hitoshi Nakayama, Hidetake Kurihara, Yasu S Morita, Taroh Kinoshita, Laura Mauri, Alessandro Prinetti, Sandro Sonnino, Noriko Yokoyama, Hideoki Ogawa, Kenji Takamori, Kazuhisa Iwabuchi
Pathogenic mycobacteria use virulence factors, including mannose-capped lipoarabinomannan (ManLAM), to survive in host phagocytic cells, such as neutrophils. We assessed the roles of lactosylceramide (LacCer, CDw17)-enriched lipid rafts in the phagocytosis of mycobacteria by human neutrophils and in the intracellular fate of phagocytosed mycobacteria. We showed that the association of the Src family kinase (SFK) Lyn with C24 fatty acid chain-containing LacCer was essential for the phagocytosis of mycobacteria by neutrophils...
October 11, 2016: Science Signaling
Deepika Sharma, Brijendra Kumar Tiwari, Subhash Mehto, Cecil Antony, Gunjan Kak, Yogendra Singh, Krishnamurthy Natarajan
The prevalence of Mycobacterium tuberculosis (M. tb) strains eliciting drug resistance has necessitated the need for understanding the complexities of host pathogen interactions. The regulation of calcium homeostasis by Voltage Gated Calcium Channel (VGCCs) upon M. tb infection has recently assumed importance in this area. We previously showed a suppressor role of VGCC during M. tb infections and recently reported the mechanisms of its regulation by M. tb. Here in this report, we further characterize the role of VGCC in mediating defence responses of macrophages during mycobacterial infection...
2016: PloS One
Veena C Yeruva, Mamata Savanagouder, Radhika Khandelwal, Apoorva Kulkarni, Yogendra Sharma, Tirumalai R Raghunand
The hallmark feature of Mycobacterium tuberculosis (M.tb) the causative agent of human tuberculosis, is its complex lipid rich cell wall comprised primarily of mycolic acids, long chain fatty acids that play a key role in structural stability and permeability of the cell wall. In addition, they are involved in inhibiting phagosome-lysosome fusion and aid in granuloma formation during the pathogenic process. M.tb DesA1 is an essential acyl-acyl carrier protein desaturase predicted to catalyze the introduction of position specific double bonds during the biosynthesis of mycolic acids...
October 6, 2016: Biochemical and Biophysical Research Communications
Punsiri M Colonne, Caylin G Winchell, Joseph G Graham, Frances I Onyilagha, Laura J MacDonald, Heike R Doeppler, Peter Storz, Richard C Kurten, Paul A Beare, Robert A Heinzen, Daniel E Voth
Coxiella burnetii is an intracellular bacterial pathogen that causes human Q fever, an acute flu-like illness that can progress to chronic endocarditis and liver and bone infections. Humans are typically infected by aerosol-mediated transmission, and C. burnetii initially targets alveolar macrophages wherein the pathogen replicates in a phagolysosome-like niche known as the parasitophorous vacuole (PV). C. burnetii manipulates host cAMP-dependent protein kinase (PKA) signaling to promote PV formation, cell survival, and bacterial replication...
October 2016: PLoS Pathogens
Reeshan Ul Quraish, Norihiro Sudou, Kaori Nomura-Komoike, Fumi Sato, Hiroki Fujieda
PURPOSE: p27(KIP1) (p27), originally identified as a cell cycle inhibitor, is now known to have multifaceted roles beyond cell cycle regulation. p27 is required for the normal histogenesis of the RPE, but the role of p27 in the mature RPE remains elusive. To define the role of p27 in the maintenance and function of the RPE, we investigated the effects of p27 deletion on the responses of the RPE after photoreceptor damage. METHODS: Photoreceptor damage was induced in wild-type (WT) and p27 knockout (KO) mice with N-methyl-N-nitrosourea (MNU) treatment...
2016: Molecular Vision
Weiyue Zheng, Masataka Umitsu, Ishaan Jagan, Charles W Tran, Noboru Ishiyama, Michael BeGora, Kiyomi Araki, Pamela S Ohashi, Mitsuhiko Ikura, Senthil K Muthuswamy
The polarity protein Scribble (SCRIB) regulates apical-basal polarity, directional migration and tumour suppression in Drosophila and mammals. Here we report that SCRIB is an important regulator of myeloid cell functions including bacterial infection and inflammation. SCRIB interacts directly with the NADPH oxidase (NOX) complex in a PSD95/Dlg/ZO-1 (PDZ)-domain-dependent manner and is required for NOX-induced reactive oxygen species (ROS) generation in culture and in vivo. On bacterial infection, SCRIB localized to phagosomes in a leucine-rich repeat-dependent manner and promoted ROS production within phagosomes to kill bacteria...
October 3, 2016: Nature Cell Biology
Gabrielle Lê-Bury, Chantal Deschamps, Audrey Dumas, Florence Niedergang
Macrophages are phagocytic cells that play a major role at the crossroads between innate and specific immunity. They can be infected by the human immunodeficiency virus (HIV)-1 and because of their resistance to its cytopathic effects they can be considered to be persistent viral reservoirs. In addition, HIV-infected macrophages exhibit defective functions that contribute to the development of opportunistic diseases. The exact mechanism by which HIV-1 impairs the phagocytic response of macrophages was unknown...
2016: Journal of Visualized Experiments: JoVE
Florence Marie-Anaïs, Julie Mazzolini, Pierre Bourdoncle, Florence Niedergang
Phagocytosis is a mechanism used by specialized cells to internalize and eliminate microorganisms or cellular debris. It relies on profound rearrangements of the actin cytoskeleton that is the driving force for plasma membrane extension around the particle. In addition, efficient engulfment of large material relies on focal exocytosis of intracellular compartments. This process is highly dynamic and numerous molecular players have been described to have a role during phagocytic cup formation. The precise regulation in time and space of all of these molecules, however, remains elusive...
2016: Journal of Visualized Experiments: JoVE
Chencheng Fang, Jiming Zhang, Nan Lu, Peng Li, Yu Fan, Yuexi Kang, Chun Yang, Yonglin He
Objective To observe the effect of zinc-dependent metalloprotease 1 (Zmp1) of Bacillus Calmette Guerin vaccine (BCG) on the proliferation and phagosome-lysosome fusion of RAW264.7 mouse macrophage. Methods Zmp1 was expressed in E.coli BL21 (DE3) and purified by metal chelate magnetic beads. RAW264.7 cells were incubated with the purified Zmp1. Cell proliferation was detected at 0, 24, 48, 72 and 96 hours by cell counting kit-8 (CCK-8) assay and cell cycle distribution was detected by flow cytometry (FCM). The formation of phagosome was induced after RAW264...
October 2016: Xi Bao Yu Fen Zi Mian Yi Xue za Zhi, Chinese Journal of Cellular and Molecular Immunology
Myriam Lawand, Anastasia Abramova, Valérie Manceau, Sebastian Springer, Peter van Endert
Cross-presentation of phagocytosed Ags by MHC class I (MHC-I) molecules is thought to involve transport of cytosolic peptides into dendritic cell phagosomes, mediated by TAP transporters recruited from the endoplasmic reticulum. However, because pure and tightly sealed phagosomes are difficult to obtain, direct evidence for peptide transport into phagosomes has remained limited. Moreover, the parameters determining peptide uptake by, and survival in, phagosomes remain little characterized. In this study, we monitored peptide import into phagosomes by flow cytometry using two types of fluorescent reporter peptides, one of which directly bound to intraphagosomal beads...
September 23, 2016: Journal of Immunology: Official Journal of the American Association of Immunologists
Kuldeep Verma, Tomoyoshi Nozaki, Sunando Datta
Entamoeba histolytica, the causative agent of amoebic colitis and liver abscess in human, ingests the intestinal bacteria and variety of host cells. Phagocytosis of bacteria by the amebic trophozoite has been reported to be important for the virulence of the parasite. Here, we set out to characterize different stages of phagocytosis of type 1 E. coli and investigated the role of a set of amoebic Rab GTPases in the process. The localizations of the Rab GTPases during different stages of the phagocytosis were investigated using laser scanning confocal microscopy and their functional relevance were determined using fluorescence activated cell sorter based assay as well as colony forming unit assay...
September 24, 2016: Molecular Microbiology
Pei Zhou, Yu-Zhen Tan, Hai-Jie Wang, Ting Li, Tao He, Ying Yu, Jian Zhang, Dan Zhang
Clearance of the apoptotic cells by phagocytes plays pivotal roles in maintenance of tissue homeostasis, promotion of immunological tolerance and anti-inflammatory response. Recent studies show that autophagy is involved in phagocytosis of the apoptotic cells. However, contribution of autophagy to phagocytosis of the apoptotic cells by macrophages is not clearly defined. Here, we assessed cytoprotective effect of autophagy on clearance of the apoptotic cells. Apoptosis of murine splenic lymphocytes and human T-cell leukemia cells was induced with cyclophosphamide...
September 20, 2016: Experimental Cell Research
Catherine M Buckley, Navin Gopaldass, Cristina Bosmani, Simon A Johnston, Thierry Soldati, Robert H Insall, Jason S King
Macropinocytosis is an ancient mechanism that allows cells to harvest nutrients from extracellular media, which also allows immune cells to sample antigens from their surroundings. During macropinosome formation, bulk plasma membrane is internalized with all its integral proteins. It is vital for cells to salvage these proteins before degradation, but the mechanisms for sorting them are not known. Here we describe the evolutionarily conserved recruitment of the WASH (WASP and SCAR homolog) complex to both macropinosomes and phagosomes within a minute of internalization...
October 4, 2016: Proceedings of the National Academy of Sciences of the United States of America
L J Wang, X W Sun, F Y Guo, Y J Zhao, Z H Zhang, Z Q Zhao
Transcriptome analysis of Inner Mongolia Cashmere goat and Dazu black goat generated 38,772,947 and 38,771,668 clean pair end reads, respectively, which were assembled into 72,422 and 80,069 unigenes by Trinity, respectively. For Inner Mongolia Cashmere goat, 26,051 and 10,100 unigenes were assigned to gene ontology (GO) categories and clusters of orthologous groups, respectively. A total of 32,772 unigenes can comment to SWISS-Prot database, and the Kyoto Encyclopedia of Genes and Genomes Pathway database (KEGG) mapped 24,420 unigenes...
September 20, 2016: Reproduction in Domestic Animals, Zuchthygiene
Natalia Rios, Lucía Piacenza, Madia Trujillo, Alejandra Martínez, Verónica Demicheli, Carolina Prolo, María Noel Álvarez, Gloria V López, Rafael Radi
The specific and sensitive detection of peroxynitrite (ONOO(‒)/ONOOH) in biological systems is a great challenge due to its high reactivity towards several biomolecules. Herein, we validated the advantages of using fluorescein-boronate (Fl-B) as a highly sensitive fluorescent probe for the direct detection of peroxynitrite under biologically-relevant conditions in two different cell models. The synthesis of Fl-B was achieved by a very simply two-step conversion synthetic route with high purity (> 99 %) and overall yield (∼ 42%)...
September 15, 2016: Free Radical Biology & Medicine
Suraj P Parihar, Mary-Anne Hartley, Ramona Hurdayal, Reto Guler, Frank Brombacher
We recently demonstrated that statins mediate protection against intracellular pathogens, Mycobacterium tuberculosis and Listeria monocytogenes in mice. Here, we investigated the immunomodulatory potential of simvastatin as a topical or systemic host-directed drug therapy in controlling inflammatory responses in an experimental mouse model of cutaneous leishmaniasis caused by Leishmania major (LV39). In an ear infection model, topical application of simvastatin directly on established lesions significantly reduced severity of the disease reflected by ear lesion size and ulceration...
2016: Scientific Reports
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