scholarly journals Anaplasma phagocytophilum Dihydrolipoamide Dehydrogenase 1 Affects Host-Derived Immunopathology during Microbial Colonization

2012 ◽  
Vol 80 (9) ◽  
pp. 3194-3205 ◽  
Author(s):  
Gang Chen ◽  
Maiara S. Severo ◽  
Olivia S. Sakhon ◽  
Anthony Choy ◽  
Michael J. Herron ◽  
...  
Keyword(s):  
Anaplasma Phagocytophilum ◽  
Extramedullary Hematopoiesis ◽  
Microbial Colonization ◽  
Dihydrolipoamide Dehydrogenase ◽  
Disease Etiology ◽  
Content Type ◽  
Granulocytic Anaplasmosis ◽  
Transposon Insertion ◽  
Pathogen Load ◽  
Mammalian Infection

ABSTRACTAnaplasma phagocytophilumis a tick-borne rickettsial pathogen that provokes an acute inflammatory response during mammalian infection. The illness caused byA. phagocytophilum, human granulocytic anaplasmosis, occurs irrespective of pathogen load and results instead from host-derived immunopathology. Thus, characterizingA. phagocytophilumgenes that affect the inflammatory process is critical for understanding disease etiology. By using anA. phagocytophilumHimar1 transposon mutant library, we showed that a single transposon insertion into theA. phagocytophilumdihydrolipoamide dehydrogenase 1 gene (lpda1[APH_0065]) affects inflammation during infection.A. phagocytophilumlackinglpda1revealed enlargement of the spleen, increased splenic extramedullary hematopoiesis, and altered clinicopathological abnormalities during mammalian colonization. Furthermore, LPDA1-derived immunopathology was independent of neutrophil infection and correlated with enhanced reactive oxygen species from NADPH oxidase and nuclear factor (NF)-κB signaling in macrophages. Taken together, these findings suggest the presence of different signaling pathways in neutrophils and macrophages duringA. phagocytophiluminvasion and highlight the importance of LPDA1 as an immunopathological molecule.

scholarly journals Anaplasma phagocytophilum Infects Mast Cells via α1,3-Fucosylated but Not Sialylated Glycans and Inhibits IgE-Mediated Cytokine Production and Histamine Release

2011 ◽  
Vol 79 (7) ◽  
pp. 2717-2726 ◽  
Author(s):  
Nore Ojogun ◽  
Brian Barnstein ◽  
Bernice Huang ◽  
Carole A. Oskeritzian ◽  
Jonathon W. Homeister ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Anaplasma Phagocytophilum ◽  
Defense Mechanisms ◽  
Cell Activation ◽  
Mast Cell Activation ◽  
Necrosis Factor Alpha ◽  
Content Type ◽  
Murine Bone Marrow ◽  
Granulocytic Anaplasmosis

ABSTRACTMast cells are sentinels for infection. Upon exposure to pathogens, they release their stores of proinflammatory cytokines, chemokines, and histamine. Mast cells are also important for the control of certain tick-borne infections.Anaplasma phagocytophilumis an obligate intracellular tick-transmitted bacterium that infects neutrophils to cause the emerging disease granulocytic anaplasmosis.A. phagocytophilumadhesion to and infection of neutrophils depend on sialylated and α1,3-fucosylated glycans. We investigated the hypotheses thatA. phagocytophiluminvades mast cells and inhibits mast cell activation. We demonstrate thatA. phagocytophilumbinds and/or infects murine bone marrow-derived mast cells (BMMCs), murine peritoneal mast cells, and human skin-derived mast cells.A. phagocytophiluminfection of BMMCs depends on α1,3-fucosylated, but not sialylated, glycans.A. phagocytophilumbinding to and invasion of BMMCs do not elicit proinflammatory cytokine secretion. Moreover,A. phagocytophilum-infected cells are inhibited in the release of tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), IL-13, and histamine following stimulation with IgE or antigen. Thus,A. phagocytophilummitigates mast cell activation. These findings potentially represent a novel means by whichA. phagocytophilumusurps host defense mechanisms and shed light on the interplay between mast cells and vector-borne bacterial pathogens.

scholarly journals Dexamethasone-Induced Cytokine Changes Associated with Diminished Disease Severity in Horses Infected with Anaplasma phagocytophilum

2011 ◽  
Vol 18 (11) ◽  
pp. 1962-1968 ◽  
Author(s):  
R. S. Davies ◽  
J. E. Madigan ◽  
E. Hodzic ◽  
D. L Borjesson ◽  
J. S. Dumler
Keyword(s):  
Disease Severity ◽  
Anaplasma Phagocytophilum ◽  
Macrophage Activation ◽  
Clinical Signs ◽  
Proinflammatory Response ◽  
Content Type ◽  
Granulocytic Anaplasmosis ◽  
Limb Edema ◽  
Ifn Γ ◽  
Dexamethasone Suppression

ABSTRACTAnaplasma phagocytophilumis the zoonotic cause of granulocytic anaplasmosis. We hypothesized that immune response, specifically gamma interferon (IFN-γ), plays a role in disease severity. To test this, horses were infected andIFNGexpression was pharmacologically downregulated using corticosteroids. Eight horses were infected withA. phagocytophilum; 4 received dexamethasone on days 4 to 8 of infection. Clinical signs, hematologic parameters, and transcription of cytokine/chemokine genes were compared among treated and untreated horses. Infection was quantitated bymsp2real-time PCR and microscopy. As anticipated, there was significantly greater leukopenia, thrombocytopenia, and anemia in infected versus uninfected horses. TheA. phagocytophilumload was higher for dexamethasone-treated horses. Dexamethasone reducedIFNGtranscription by day 12 andIL-8andIL-18by days 7 to 9 and increasedIL-4on day 7. The ratio ofIL-10toIFNGwas increased by dexamethasone on day 9. There were no hematologic differences between the infected horses. Dexamethasone suppression of proinflammatory response resulted in delayed infection-induced limb edema and decreased icterus, anorexia, and reluctance to move between days 6 and 9 and lower fever on day 7. These results underscore the utility of the equine model of granulocytic anaplasmosis and suggest that Th1 proinflammatory response plays a role in worsening disease severity and that disease severity can be decreased by modulating proinflammatory response. A role for Th1 response and macrophage activation in hematologic derangements elicited byA. phagocytophilumis not supported by these data and remains unproven.

scholarly journals Expression and Immunogenicity of Recombinant Immunoreactive Surface Protein 2 of Anaplasma phagocytophilum

2012 ◽  
Vol 19 (6) ◽  
pp. 919-923 ◽  
Author(s):  
Qiang Yu ◽  
Chuang-fu Chen ◽  
Qiang Chen ◽  
Li-juan Zhang
Keyword(s):  
Recombinant Protein ◽  
Anaplasma Phagocytophilum ◽  
Surface Protein ◽  
Immunofluorescence Assay ◽  
Enzyme Linked Immunosorbent Assay ◽  
Content Type ◽  
Major Surface Protein ◽  
Granulocytic Anaplasmosis ◽  
Major Surface ◽  
Diagnostic Reagent

ABSTRACTHuman granulocytic anaplasmosis (HGA), caused byAnaplasma phagocytophilum, is an emerging tick-borne zoonotic disease throughout the world. The first HGA cases in China were documented in 2008, and the greatest challenge posed by the disease is rapid and accurate diagnosis during the acute phage of illness. In this study, we successfully cloned and expressed anA. phagocytophilumimmunoreactive surface protein (major surface protein 2 [MSP2]) and demonstrated that this recombinant protein has natural immunogenicity by Western blotting and enzyme-linked immunosorbent assay (ELISA) using human HGA-positive sera and reference rabbit HGA-positive sera. The rabbit antisera against the recombinant protein also reacted actively with the natural antigen ofA. phagocytophilumby immunofluorescence assay (IFA). No cross-reaction was observed between the recombinant protein and rabbit antisera against 10 common members of the orderRickettsialesby ELISA when the sera were diluted more than 1:100. We concluded that the recombinant MSP2 protein exhibited excellent antigenicity and specificity, results that should lay the foundation for the development of a simple and rapid diagnostic reagent and a vaccination for anaplasmosis.

scholarly journals Anaplasma phagocytophilum Inhibits Apoptosis and Promotes Cytoskeleton Rearrangement for Infection of Tick Cells

2013 ◽  
Vol 81 (7) ◽  
pp. 2415-2425 ◽  
Author(s):  
Nieves Ayllón ◽  
Margarita Villar ◽  
Ann T. Busby ◽  
Katherine M. Kocan ◽  
Edmour F. Blouin ◽  
...  
Keyword(s):  
Salivary Glands ◽  
Anaplasma Phagocytophilum ◽  
Ixodes Scapularis ◽  
Content Type ◽  
Granulocytic Anaplasmosis ◽  
New Genes ◽  
Voltage Dependent ◽  
Selective Channel ◽  
Cytoskeleton Rearrangement

ABSTRACTAnaplasma phagocytophilumcauses human granulocytic anaplasmosis. Infection with this zoonotic pathogen affects gene expression in both the vertebrate host and the tick vector,Ixodes scapularis. Here, we identified new genes, including spectrin alpha chain or alpha-fodrin (CG8) and voltage-dependent anion-selective channel or mitochondrial porin (T2), that are involved inA. phagocytophiluminfection/multiplication and the tick cell response to infection. The pathogen downregulated the expression of CG8 in tick salivary glands and T2 in both the gut and salivary glands to inhibit apoptosis as a mechanism to subvert host cell defenses and increase infection. In the gut, the tick response to infection through CG8 upregulation was used by the pathogen to increase infection due to the cytoskeleton rearrangement that is required for pathogen infection. These results increase our understanding of the role of tick genes duringA. phagocytophiluminfection and multiplication and demonstrate that the pathogen uses similar strategies to establish infection in both vertebrate and invertebrate hosts.

scholarly journals Immunization against Anaplasma phagocytophilum Adhesin Binding Domains Confers Protection against Infection in the Mouse Model

2020 ◽  
Vol 88 (10) ◽  
Author(s):  
Waheeda A. Naimi ◽  
Jacob J. Gumpf ◽  
Ryan S. Green ◽  
Jerilyn R. Izac ◽  
Matthew P. Zellner ◽  
...  
Keyword(s):  
Peripheral Blood ◽  
Anaplasma Phagocytophilum ◽  
Protein A ◽  
Keyhole Limpet Hemocyanin ◽  
Host Cells ◽  
Content Type ◽  
Binding Domains ◽  
Granulocytic Anaplasmosis

ABSTRACT Anaplasma phagocytophilum causes granulocytic anaplasmosis, a debilitating infection that can be fatal in the immunocompromised. It also afflicts animals, including dogs, horses, and sheep. No granulocytic anaplasmosis vaccine exists. Because A. phagocytophilum is an obligate intracellular bacterium, inhibiting microbe-host cell interactions that facilitate invasion can disrupt infection. The binding domains of A. phagocytophilum adhesins A. phagocytophilum invasion protein A (AipA), A. phagocytophilum surface protein (Asp14), and outer membrane protein A (OmpA) are essential for optimal bacterial entry into host cells, but their relevance to infection in vivo is undefined. In this study, C57BL/6 mice were immunized with a cocktail of keyhole limpet hemocyanin-conjugated peptides corresponding to the AipA, Asp14, and OmpA binding domains in alum followed by challenge with A. phagocytophilum. The bacterial peripheral blood burden was pronouncedly reduced in immunized mice compared to controls. Examination of pre- and postchallenge sera from these mice revealed that immunization elicited antibodies against AipA and Asp14 peptides but not OmpA peptide. Nonetheless, pooled sera from pre- and postchallenge groups, but not from control groups, inhibited A. phagocytophilum infection of HL-60 cells. Adhesin domain immunization also elicited interferon gamma (IFN-γ)-producing CD8-positive (CD8+) T cells. A follow-up study confirmed that immunization against only the AipA or Asp14 binding domain was sufficient to reduce the bacterial peripheral blood load in mice following challenge and elicit antibodies that inhibit A. phagocytophilum cellular infection in vitro. These data demonstrate that AipA and Asp14 are critical for A. phagocytophilum to productively infect mice, and immunization against their binding domains elicits a protective immune response.

scholarly journals Granulocytic anaplasmosis in captive ring-tailed lemur (Lemur catta) in Poland

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Łukasz Adaszek ◽  
Anna Wilczyńska ◽  
Jerzy Ziętek ◽  
Marcin Kalinowski ◽  
Oliwier Teodorowski ◽  
...  
Keyword(s):  
Anaplasma Phagocytophilum ◽  
Polymerase Chain Reaction Test ◽  
Anaplasma Ovis ◽  
Case Presentation ◽  
Granulocytic Anaplasmosis ◽  
Pcr Product ◽  
Polymerase Chain ◽  
Obligate Intracellular Bacteria ◽  
Chain Reaction Test ◽  
Anaplasma Bovis

Abstract Background Anaplasma are obligate intracellular bacteria and aetiological agents of tick-borne diseases of both veterinary and medical interest. The genus Anaplasma comprises six species: Anaplasma marginale, Anaplasma centrale, Anaplasma ovis, Anaplasma phagocytophilum, Anaplasma bovis and Anaplasma platys. They can infect humans, carnivores, ruminants, rodents, insectivores, birds and reptiles. The aim of this study was to present the first clinical case of granulocytic anaplasmosis in a captive ring-tailed lemur in Poland. Case presentation A 4-year-old female lemur presented anorexia, epistaxis and tick infestation. The microscopic examination of a blood smear revealed morulae in neutrophils. Polymerase chain reaction test and sequencing of obtained PCR product confirmed infection by the GU183908 Anaplasma phagocytophilum strain. Therapeutic protocol included doxycycline (2.5 mg/kg p.o., b.i.d.) for 3 weeks and the lemur recovered within 24 h. Conclusions This is the first report on granulocytic anaplasmosis in a ring-tailed lemur in Europe, indicating that A. phagocytophilum infection must also be considered in differential diagnosis in this animal species, especially in individuals with thrombocytopenia associated with Ixodes ricinus parasitism.

scholarly journals Anaplasma phagocytophilum Outer Membrane Protein A Interacts with Sialylated Glycoproteins To Promote Infection of Mammalian Host Cells

2012 ◽  
Vol 80 (11) ◽  
pp. 3748-3760 ◽  
Author(s):  
Nore Ojogun ◽  
Amandeep Kahlon ◽  
Stephanie A. Ragland ◽  
Matthew J. Troese ◽  
Juliana E. Mastronunzio ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Anaplasma Phagocytophilum ◽  
Protein A ◽  
Host Cells ◽  
Mammalian Host ◽  
Content Type ◽  
Outer Membrane Protein A ◽  
Sialylated Glycoproteins

ABSTRACTAnaplasma phagocytophilumis the tick-transmitted obligate intracellular bacterium that causes human granulocytic anaplasmosis (HGA).A. phagocytophilumbinding to sialyl Lewis x (sLex) and other sialylated glycans that decorate P selectin glycoprotein 1 (PSGL-1) and other glycoproteins is critical for infection of mammalian host cells. Here, we demonstrate the importance ofA. phagocytophilumouter membrane protein A (OmpA) APH_0338 in infection of mammalian host cells. OmpA is transcriptionally induced during transmission feeding ofA. phagocytophilum-infected ticks on mice and is upregulated during invasion of HL-60 cells. OmpA is presented on the pathogen's surface. Sera from HGA patients and experimentally infected mice recognize recombinant OmpA. Pretreatment ofA. phagocytophilumorganisms with OmpA antiserum reduces their abilities to infect HL-60 cells. The OmpA N-terminal region is predicted to contain the protein's extracellular domain. GlutathioneS-transferase (GST)-tagged versions of OmpA and OmpA amino acids 19 to 74 (OmpA19-74) but not OmpA75-205bind to, and competitively inhibitA. phagocytophiluminfection of, host cells. Pretreatment of host cells with sialidase or trypsin reduces or nearly eliminates, respectively, GST-OmpA adhesion. Therefore, OmpA interacts with sialylated glycoproteins. This study identifies the firstA. phagocytophilumadhesin-receptor pair and delineates the region of OmpA that is critical for infection.

scholarly journals CXCR2 Blockade Influences Anaplasma phagocytophilum Propagation but Not Histopathology in the Mouse Model of Human Granulocytic Anaplasmosis

2004 ◽  
Vol 11 (5) ◽  
pp. 963-968 ◽  
Author(s):  
Diana G. Scorpio ◽  
Mustafa Akkoyunlu ◽  
Erol Fikrig ◽  
J. Stephen Dumler
Keyword(s):  
Anaplasma Phagocytophilum ◽  
Tissue Injury ◽  
Treated Group ◽  
Obligate Intracellular Bacterium ◽  
Human Granulocytic Anaplasmosis ◽  
Obligate Intracellular ◽  
Liver Histopathology ◽  
Granulocytic Anaplasmosis ◽  
Infected Cells ◽  
And Control

ABSTRACT Anaplasma phagocytophilum is an obligate intracellular bacterium that infects neutrophils and causes human granulocytic anaplasmosis. Infection induces neutrophil secretion of interleukin-8 or murine homologs and perpetuates infection by recruiting susceptible neutrophils. We hypothesized that antibody blockade of CXCR2 would decrease A. phagocytophilum tissue load by interrupting neutrophil recruitment but would not influence murine hepatic pathology. C3H-scid mice were treated with CXCR2 antiserum or control prior to or on day 14 after infection. Quantitative PCR and immunohistochemistry for A. phagocytophilum were performed and severity of liver histopathology was ranked. Control mice had more infected cells in tissues than the anti-CXCR2-treated group. The histopathological rank was not different between treated and control animals. Infected cells of control mice clustered in tissue more than in treated mice. The results support the hypothesis of bacterial propagation through chemokine induction and confirm that tissue injury is unrelated to A. phagocytophilum tissue load.

Using Machine Learning to Identify Metabolomic Signatures of Pediatric Chronic Kidney Disease Etiology

2022 ◽  
pp. ASN.2021040538
Author(s):  
Arthur M. Lee ◽  
Jian Hu ◽  
Yunwen Xu ◽  
Alison G. Abraham ◽  
Rui Xiao ◽  
...  
Keyword(s):  
Machine Learning ◽  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Gut Microbiome ◽  
Support Vector ◽  
Pathway Enrichment Analysis ◽  
Disease Etiology ◽  
Content Type ◽  
Extreme Gradient Boosting ◽  
Pediatric Ckd

BackgroundUntargeted plasma metabolomic profiling combined with machine learning (ML) may lead to discovery of metabolic profiles that inform our understanding of pediatric CKD causes. We sought to identify metabolomic signatures in pediatric CKD based on diagnosis: FSGS, obstructive uropathy (OU), aplasia/dysplasia/hypoplasia (A/D/H), and reflux nephropathy (RN).MethodsUntargeted metabolomic quantification (GC-MS/LC-MS, Metabolon) was performed on plasma from 702 Chronic Kidney Disease in Children study participants (n: FSGS=63, OU=122, A/D/H=109, and RN=86). Lasso regression was used for feature selection, adjusting for clinical covariates. Four methods were then applied to stratify significance: logistic regression, support vector machine, random forest, and extreme gradient boosting. ML training was performed on 80% total cohort subsets and validated on 20% holdout subsets. Important features were selected based on being significant in at least two of the four modeling approaches. We additionally performed pathway enrichment analysis to identify metabolic subpathways associated with CKD cause.ResultsML models were evaluated on holdout subsets with receiver-operator and precision-recall area-under-the-curve, F1 score, and Matthews correlation coefficient. ML models outperformed no-skill prediction. Metabolomic profiles were identified based on cause. FSGS was associated with the sphingomyelin-ceramide axis. FSGS was also associated with individual plasmalogen metabolites and the subpathway. OU was associated with gut microbiome–derived histidine metabolites.ConclusionML models identified metabolomic signatures based on CKD cause. Using ML techniques in conjunction with traditional biostatistics, we demonstrated that sphingomyelin-ceramide and plasmalogen dysmetabolism are associated with FSGS and that gut microbiome–derived histidine metabolites are associated with OU.

scholarly journals Chitosan Biosynthesis and Virulence in the Human Fungal Pathogen Cryptococcus gattii

mSphere ◽  
2019 ◽  
Vol 4 (5) ◽  
Author(s):  
Woei C. Lam ◽  
Rajendra Upadhya ◽  
Charles A. Specht ◽  
Abigail E. Ragsdale ◽  
Camaron R. Hole ◽  
...  
Keyword(s):  
Cell Wall ◽  
Fungal Pathogen ◽  
Cryptococcus Gattii ◽  
Fungal Cell Wall ◽  
Fungal Pathogenesis ◽  
Protective Response ◽  
Fungal Cell ◽  
Fungal Virulence ◽  
Content Type ◽  
Mammalian Infection

ABSTRACT Cryptococcus gattii R265 is a hypervirulent fungal strain responsible for the recent outbreak of cryptococcosis in Vancouver Island of British Columbia in Canada. It differs significantly from Cryptococcus neoformans in its natural environment, its preferred site in the mammalian host, and its pathogenesis. Our previous studies of C. neoformans have shown that the presence of chitosan, the deacetylated form of chitin, in the cell wall attenuates inflammatory responses in the host, while its absence induces robust immune responses, which in turn facilitate clearance of the fungus and induces a protective response. The results of the present investigation reveal that the cell wall of C. gattii R265 contains a two- to threefold larger amount of chitosan than that of C. neoformans. The genes responsible for the biosynthesis of chitosan are highly conserved in the R265 genome; the roles of the three chitin deacetylases (CDAs) have, however, been modified. To deduce their roles, single and double CDA deletion strains and a triple CDA deletion strain were constructed in a R265 background and were subjected to mammalian infection studies. Unlike C. neoformans where Cda1 has a discernible role in fungal pathogenesis, in strain R265, Cda3 is critical for virulence. Deletion of either CDA3 alone or in combination with another CDA (cda1Δ3Δ or cda2Δ3Δ) or both (cda1Δ2Δ3Δ) rendered the fungus avirulent and cleared from the infected host. Moreover, the cda1Δ2Δ3Δ strain of R265 induced a protective response to a subsequent infection with R265. These studies begin to illuminate the regulation of chitosan biosynthesis of C. gattii and its subsequent effect on fungal virulence. IMPORTANCE The fungal cell wall is an essential organelle whose components provide the first line of defense against host-induced antifungal activity. Chitosan is one of the carbohydrate polymers in the cell wall that significantly affects the outcome of host-pathogen interaction. Chitosan-deficient strains are avirulent, implicating chitosan as a critical virulence factor. C. gattii R265 is an important fungal pathogen of concern due to its ability to cause infections in individuals with no apparent immune dysfunction and an increasing geographical distribution. Characterization of the fungal cell wall and understanding the contribution of individual molecules of the cell wall matrix to fungal pathogenesis offer new therapeutic avenues for intervention. In this report, we show that the C. gattii R265 strain has evolved alternate regulation of chitosan biosynthesis under both laboratory growth conditions and during mammalian infection compared to that of C. neoformans.

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