Characterization of Virulence Factors of Staphylococcus aureus: Novel Function of Known Virulence Factors That Are Implicated in Activation of Airway Epithelial Proinflammatory Response

Airway epithelial cells play a major role in initiating inflammation in response to bacterial pathogens. S. aureus is an important pathogen associated with activation of diverse types of infection characterized by inflammation dominated by polymorphonuclear leukocytes. This bacterium frequently causes lung infection, which is attributed to virulence factors. Many of virulence determinants associated with S. aureus-mediated lung infection have been known for several years. In this paper, we discuss recent advances in our understanding of known virulence factors implicated in pneumonia. We anticipate that better understanding of novel functions of known virulence factors could open the way to regulate inflammatory reactions of the epithelium and to develop effective strategies to treat S. aureus-induced airway diseases

Role of Uropathogenic Escherichia coli Virulence Factors in Development of Urinary Tract Infection and Kidney Damage

Uropathogenic Escherichia coli (UPEC) is a causative agent in the vast majority of urinary tract infections (UTIs), including cystitis and pyelonephritis, and infectious complications, which may result in acute renal failure in healthy individuals as well as in renal transplant patients. UPEC expresses a multitude of virulence factors to break the inertia of the mucosal barrier. In response to the breach by UPEC into the normally sterile urinary tract, host inflammatory responses are triggered leading to cytokine production, neutrophil influx, and the exfoliation of infected bladder epithelial cells. Several signaling pathways activated during UPEC infection, including the pathways known to activate the innate immune response, interact with calcium-dependent signaling pathways. Some UPEC isolates, however, might possess strategies to delay or suppress the activation of components of the innate host response in the urinary tract. Studies published in the recent past provide new information regarding how virulence factors of uropathogenic E. coli are involved in activation of the innate host response. Despite numerous host defense mechanisms, UPEC can persist within the urinary tract and may serve as a reservoir for recurrent infections and serious complications. Presentation of the molecular details of these events is essential for development of successful strategies for prevention of human UTIs and urological complications associated with UTIs

Identification of immunogenic proteins of the cysticercoid of Hymenolepis diminuta

Background: A wide range of molecules are used by tapeworm metacestodes to establish successful infection in the hostile environment of the host. Reports indicating the proteins in the cestode-host interactions are limited predominantly to taeniids, with no previous data available for non-taeniid species. A non-taeniid, Hymenolepis diminuta, represents one of the most important model species in cestode biology and exhibits an exceptional developmental plasticity in its life-cycle, which involves two phylogenetically distant hosts, arthropod and vertebrate. Results: We identified H. diminuta cysticercoid proteins that were recognized by sera of H. diminuta-infected rats using two-dimensional gel electrophoresis (2DE), 2D-immunoblotting, and LC-MS/MS mass spectrometry. Proteomic analysis of 42 antigenic spots revealed 70 proteins. The largest number belonged to structural proteins and to the heat-shock protein (HSP) family. These results show a number of the antigenic proteins of the cysticercoid stage, which were present already in the insect host prior to contact with the mammal host. These are the first parasite antigens that the mammal host encounters after the infection, therefore they may represent some of the molecules important in host-parasite interactions at the early stage of infection. Conclusions: These results could help in understanding how H. diminuta and other cestodes adapt to their diverse and complex parasitic life-cycles and show universal molecules used among diverse groups of cestodes to escape the host response to infection.Peer reviewe

Comparative Proteomic Analysis of Hymenolepis diminuta Cysticercoid and Adult Stages

Cestodiases are common parasitic diseases of animals and humans. As cestodes have complex lifecycles, hexacanth larvae, metacestodes (including cysticercoids), and adults produce proteins allowing them to establish invasion and to survive in the hostile environment of the host. Hymenolepis diminuta is the most commonly used model cestode in experimental parasitology. The aims of the present study were to perform a comparative proteomic analysis of two consecutive developmental stages of H. diminuta (cysticercoid and adult) and to distinguish proteins which might be characteristic for each of the stages from those shared by both stages. Somatic proteins of H. diminuta were isolated from 6-week-old cysticercoids and adult tapeworms. Cysticercoids were obtained from experimentally infected beetles, Tenebrio molitor, whereas adult worms were collected from experimentally infected rats. Proteins were separated by GeLC-MS/MS (one dimensional gel electrophoresis coupled with liquid chromatography and tandem mass spectrometry). Additionally protein samples were digested in-liquid and identified by LC-MS/MS. The identified proteins were classified according to molecular function, cellular components and biological processes. Our study showed a number of differences and similarities in the protein profiles of cysticercoids and adults; 233 cysticercoid and 182 adult proteins were identified. From these proteins, 131 were present only in the cysticercoid and 80 only in the adult stage samples. Both developmental stages shared 102 proteins; among which six represented immunomodulators and one is a potential drug target. In-liquid digestion and LC-MS/MS complemented and confirmed some of the GeLC-MS/MS identifications. Possible roles and functions of proteins identified with both proteomic approaches are discussed.Peer reviewe

Short- and long-term outcomes of continuous-flow left ventricular assist device therapy in 79 patients with end-stage heart failure

Introduction An increasing number of patients with end‑stage heart failure, along with a shortage of heart donors, necessitates the use of mechanical circulatory support. Objecti ves This single‑center retrospective study evaluated short- and long‑term outcomes of continuous‑flow left ventricular assist device (CF‑LVAD) therapy in patients with end‑stage heart failure. Patient s and methods We collected and assessed data of 79 patients (77 men, 2 women; mean age, 50.3 years; mean INTERMACS profile, 3.1) implanted with a CF‑LVAD between 2009 and 2017 (HeartMate 3 in 19 patients [24%]; HeartMate 2 in 9 [11.4%]; and HeartWare in 51 [64.6%]). Result s The mean time on CF‑LVAD support was 604 days (range, 1–1758 days). There were 2 device exchanges due to pump thrombosis and 1 explantation due to heart regeneration; 9 patients (11.4%) underwent heart transplant. Stroke (nondisabling, 48%) occurred in 27.8% of patients (ischemic in 9 patients; hemorrhagic, in 14; both types, in 1) despite the standardized anticoagulation regimen. Major gastrointestinal bleeding and pump thrombosis were reported in 13 patients (16.5%), while 18 patients (22.8%) developed driveline infections (recurrent in 15 patients [19%]). Hemorrhagic stroke and bacteremia had a negative impact on survival. Hemorrhagic stroke was the main cause of death. Survival probability was 0.9 at 1 month and 0.81, 0.71, 0.61, and 0.53 at 1, 2, 3, and 4 years, respectively. Conclusions Although CF‑LVAD support is associated with substantial adverse events, they do not significantly affect mortality (except hemorrhagic stroke and bacteremia). Novel devices seem to overcome these limitations, but larger studies are needed to support these findings

Colitis promotes adaptation of an intestinal nematode: a Heligmosomoides polygyrus mouse model system.

The precise mechanism of the very effective therapeutic effect of gastrointestinal nematodes on some autoimmune diseases is not clearly understood and is currently being intensively investigated. Treatment with living helminths has been initiated to reverse intestinal immune-mediated diseases in humans. However, little attention has been paid to the phenotype of nematodes in the IBD-affected gut and the consequences of nematode adaptation. In the present study, exposure of Heligmosomoides polygyrus larvae to the changed cytokine milieu of the intestine during colitis reduced inflammation in an experimental model of dextran sulphate sodium (DSS)- induced colitis, but increased nematode establishment in the moderate-responder BALB/c mouse strain. We used mass spectrometry in combination with two-dimensional Western blotting to determine changes in protein expression and changes in nematode antigens recognized by IgG1 in mice with colitis. We show that nematode larvae immunogenicity is changed by colitis as soon as 6 days post-infection; IgG1 did not recognize highly conserved proteins Lev-11 (isoform 1 of tropomyosin α1 chain), actin-4 isoform or FTT-2 isoform a (14-3-3 family) protein. These results indicate that changes in the small intestine provoked by colitis directly influence the nematode proteome. The unrecognized proteins seem to be key antigenic epitopes able to induce protective immune responses. The proteome changes were associated with weak immune recognition and increased larval adaptation and worm growth, altered localization in the intestine and increased survival of males but reduced worm fecundity. In this report, the mechanisms influencing nematode survival and the consequences of changed immunogenicity that reflect the immune response at the site colonized by the parasite in mice with colitis are described. The results are relevant to the use of live parasites to ameliorate IBD

The consequences of colitis in <i>H. polygyrus</i> nematodes.

<p>A. The mean number of L4 and adult worms isolated from mice with colitis infected with <i>H. polygyrus</i> (HP/COL) and from control infection (HP). B. The mean worm position (fraction of intestine length). C. Mean worm length of male and female L4, and adult <i>H. polygyrus</i> (mm). D. Sex ratio (male: female; P<0.001 Chi-square test); BALB/c mice were orally infected with 300 <i>H. polygyrus</i> L3, 3 days after DSS treatment. The mice were sacrificed at day 6 and 15 post infection. Tissue –dwelling larvae and adults were counted <i>in </i><i>situ</i> to determine the total number and distribution along small intestine. Individuals were removed, sexed and measured. The mean larval position was calculated as (number of larvae per segment x distance of segment from stomach) divided by (total larvae x intestine length). Each data point represents the means ± SE of five mice. *P < 0.05 comparing to the level of control mice infected with <i>H. polygyrus</i>. </p

Immuno-reactive spots of <i>H. polygyrus</i> L4 isolated from mice with colitis and from control mice.

<p>Silver stained two-dimensional polyacrylamide gels of <i>H. polygyrus</i> from mice without (A) and with colitis (B). Isoelectric focusing was performed with 30 μg of L4 protein using an IPG strip with a pH range of 3–10. SDS–PAGE was performed on a 12% gel, which was stained with Coomassie brilliant blue colloidal G-250. C. D. The proteins on the 2-D gel were transferred to a nitrocellulose membrane. The blot was probed with mouse serum (1:100), followed by horseradish peroxidase-conjugated anti-mouse IgG (1:20000) and visualized by enhanced chemiluminescence. Spots detected by IgG1 antibody are indicated by arrows and the numbers correlate with: 0- Lev-11 (Isoform 1 of Tropomyosin alpha-1 chain), <i>C. elegans</i> (NP_001021695.1); 1 Actin-4 isoform a, <i>C. elegans</i> (AAB04575.1), 2- UNC-15, isoform a, (myosin) <i>C. elegans</i> (CAB01965.1); 3- EFA-6, isoform c, <i>C. elegans</i> (CAM82814.1); 4- ATP synthase alpha and beta subunits, ATP synthase Alpha chain, C terminal <i>C. elegans</i> (CAA19429.1 ); 5- FTT-2 isoform a (14-3-3 protein) <i>C. elegans</i> (CAA91474.1). Arrows indicate proteins of L4 stage from mice with colitis unrecognized by IgG1 but recognized at L4 stage from control infection. </p