miR-1343 attenuates pathways of fibrosis by targeting the TGF- receptors

Irreversible respiratory obstruction resulting from progressive airway damage, inflammation and fibrosis is a feature of several chronic respiratory diseases, including cystic fibrosis (CF), idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD). The cytokine transforming growth factor β (TGF-β) has a pivotal role in promoting lung fibrosis and is implicated in respiratory disease severity. In the present study, we show that a previously uncharacterized miRNA, miR-1343, reduces the expression of both TGF-β receptor 1 and 2 by directly targeting their 3′-UTRs. After TGF-β exposure, elevated intracellular miR-1343 significantly decreases levels of activated TGF-β effector molecules, pSMAD2 (phosphorylated SMAD2) and pSMAD3 (phosphorylated SMAD3), when compared with a non-targeting control miRNA. As a result, the abundance of fibrotic markers is reduced, cell migration into a scratch wound impaired and epithelial-to-mesenchymal transition (EMT) repressed. Mature miR-1343 is readily detected in human neutrophils and HL-60 cells and is activated in response to stress in A549 lung epithelial cells. miR-1343 may have direct therapeutic applications in fibrotic lung disease

Small Intestine Early Innate Immunity Response during Intestinal Colonization by Escherichia coli Depends on Its Extra-Intestinal Virulence Status

International audienceUropathogenic Escherichia coli (UPEC) strains live as commensals in the digestive tract of the host, but they can also initiate urinary tract infections. The aim of this work was to determine how a host detects the presence of a new UPEC strain in the digestive tract. Mice were orally challenged with UPEC strains 536 and CFT073, non-pathogenic strain K12 MG1655, and ΔPAI-536, an isogenic mutant of strain 536 lacking all 7 pathogenicity islands whose virulence is drastically attenuated. Intestinal colonization was measured, and cytokine expression was determined in various organs recovered from mice after oral challenge. UPEC strain 536 efficiently colonized the mouse digestive tract, and prior Enterobacteriaceae colonization was found to impact strain 536 colonization efficiency. An innate immune response, detected as the production of TNFα, IL-6 and IL-10 cytokines, was activated in the ileum 48 hours after oral challenge with strain 536, and returned to baseline within 8 days, without a drop in fecal pathogen load. Although inflammation was detected in the ileum, histology was normal at the time of cytokine peak. Comparison of cytokine secretion 48h after oral gavage with E. coli strain 536, CFT073, MG1655 or ΔPAI-536 showed that inflammation was more pronounced with UPECs than with non-pathogenic or attenuated strains. Pathogenicity islands also seemed to be involved in host detection, as IL-6 intestinal secretion was increased after administration of E. coli strain 536, but not after administration of ΔPAI-536. In conclusion, UPEC colonization of the mouse digestive tract activates acute phase inflammatory cytokine secretion but does not trigger any pathological changes, illustrating the opportunistic nature of UPECs. This digestive tract colonization model will be useful for studying the factors controlling the switch from commensalism to pathogenicity

Deutungsmuster von Lehrkräften in Bezug auf die handlungsleitenden Prinzipien eines entwicklungsförderlichen Unterrichts. Ergebnisse von Gruppendiskussionen in inklusiven und exklusiven Förderarrangements

Lütje-Klose B, Kurnitzki S, Serke B. Deutungsmuster von Lehrkräften in Bezug auf die handlungsleitenden Prinzipien eines entwicklungsförderlichen Unterrichts. Ergebnisse von Gruppendiskussionen in inklusiven und exklusiven Förderarrangements. In: Redlich H, Schäfer L, Wachtel G, Zehbe K, Moser V, eds. Veränderung und Beständigkeit in Zeiten der Inklusion. Perspektiven sonderpädagogischer Professionalisierung. Bad Heilbrunn: Klinkhardt; 2015: 224-240

Real-time estimation of disease activity in emerging outbreaks using internet search information.

Understanding the behavior of emerging disease outbreaks in, or ahead of, real-time could help healthcare officials better design interventions to mitigate impacts on affected populations. Most healthcare-based disease surveillance systems, however, have significant inherent reporting delays due to data collection, aggregation, and distribution processes. Recent work has shown that machine learning methods leveraging a combination of traditionally collected epidemiological information and novel Internet-based data sources, such as disease-related Internet search activity, can produce meaningful "nowcasts" of disease incidence ahead of healthcare-based estimates, with most successful case studies focusing on endemic and seasonal diseases such as influenza and dengue. Here, we apply similar computational methods to emerging outbreaks in geographic regions where no historical presence of the disease of interest has been observed. By combining limited available historical epidemiological data available with disease-related Internet search activity, we retrospectively estimate disease activity in five recent outbreaks weeks ahead of traditional surveillance methods. We find that the proposed computational methods frequently provide useful real-time incidence estimates that can help fill temporal data gaps resulting from surveillance reporting delays. However, the proposed methods are limited by issues of sample bias and skew in search query volumes, perhaps as a result of media coverage

Metabolic Stress Drives Keratinocyte Defenses against Staphylococcus aureus Infection

Human skin is commonly colonized and infected by Staphylococcus aureus. Exactly how these organisms are sensed by keratinocytes has not been clearly delineated. Using a combination of metabolic and transcriptomic methodologies, we found that S. aureus infection is sensed as a metabolic stress by the hypoxic keratinocytes. This induces HIF1α signaling, which promotes IL-1β production and stimulates aerobic glycolysis to meet the metabolic requirements of infection. We demonstrate that staphylococci capable of glycolysis, including WT and agr mutants, readily induce HIF1α responses. In contrast, Δpyk glycolytic mutants fail to compete with keratinocytes for their metabolic needs. Suppression of glycolysis using 2-DG blocked keratinocyte production of IL-1β in vitro and significantly exacerbated the S. aureus cutaneous infection in a murine model. Our data suggest that S. aureus impose a metabolic stress on keratinocytes that initiates signaling necessary to promote both glycolysis and the proinflammatory response to infection

Necroptosis Promotes Staphylococcus aureus Clearance by Inhibiting Excessive Inflammatory Signaling

Staphylococcus aureus triggers inflammation through inflammasome activation and recruitment of neutrophils, responses that are critical for pathogen clearance but are associated with substantial tissue damage. We postulated that necroptosis, cell death mediated by the RIPK1/RIPK3/MLKL pathway, would function to limit pathological inflammation. In models of skin infection or sepsis, Mlkl−/− mice had high bacterial loads, an inability to limit interleukin-1b (IL-1b) production, and excessive inflammation. Similarly, mice treated with RIPK1 or RIPK3 inhibitors had increased bacterial loads in a model of sepsis. Ripk3−/− mice exhibited increased staphylococcal clearance and decreased inflammation in skin and systemic infection, due to direct effects of RIPK3 on IL-1b activation and apoptosis. In contrast to Casp1/4−/− mice with defective S. aureus killing, the poor outcomes of Mlkl−/− mice could not be attributed to impaired phagocytic function. We conclude that necroptotic cell death limits the pathological inflammation induced by S. aureus

Toxin-Induced Necroptosis Is a Major Mechanism of <i>Staphylococcus aureus</i> Lung Damage

<div><p><i>Staphylococcus aureus</i> USA300 strains cause a highly inflammatory necrotizing pneumonia. The virulence of this strain has been attributed to its expression of multiple toxins that have diverse targets including ADAM10, NLRP3 and CD11b. We demonstrate that induction of necroptosis through RIP1/RIP3/MLKL signaling is a major consequence of <i>S</i>. <i>aureus</i> toxin production. Cytotoxicity could be prevented by inhibiting either RIP1 or MLKL signaling and <i>S</i>. <i>aureus</i> mutants lacking <i>agr</i>, <i>hla</i> or Hla pore formation, <i>lukAB</i> or <i>psms</i> were deficient in inducing cell death in human and murine immune cells. Toxin-associated pore formation was essential, as cell death was blocked by exogenous K+ or dextran. MLKL inhibition also blocked caspase-1 and IL-1β production, suggesting a link to the inflammasome. <i>Rip3</i><i>^-/-</i> mice exhibited significantly improved staphylococcal clearance and retained an alveolar macrophage population with CD200R and CD206 markers in the setting of acute infection, suggesting increased susceptibility of these leukocytes to necroptosis. The importance of this anti-inflammatory signaling was indicated by the correlation between improved outcome and significantly decreased expression of KC, IL-6, TNF, IL-1α and IL-1β in infected mice. These findings indicate that toxin-induced necroptosis is a major cause of lung pathology in <i>S</i>. <i>aureus</i> pneumonia and suggest the possibility of targeting components of this signaling pathway as a therapeutic strategy.</p></div

TNFα, IL-6, and IL-10 cytokine ELISA measurements in the ileum (A), caecum (B) and colon (C) 2 days after oral gavage with 100 μL of PBS (controls), and 2 or 8 days after oral gavage with 10⁷ CFU of <i>E</i>. <i>coli</i> strain 536.

<p>Box and whiskers represent medians and interquartile ranges. Lines indicate significant differences with p<0.01 (Mann-Whitney U test).</p

Intestinal colonization after a single oral challenge with 10⁷ CFU of UPEC strain 536.

<p>Fecal pellets were individually collected from C3H/HeOuJ (A) or C57BL6/J (B) mice every day or every other day after oral challenge. <i>E</i>. <i>coli</i> strain 536 CFUs were enumerated in the feces by serial dilution on MacConkey+streptomycin (30 μg/mL) agar plates and expressed as log₁₀ (CFU/g feces). Mean bacterial loads were not significantly different over time (Fig 1A and 1B, one-way ANOVA with Bonferroni’s correction for multiple comparisons). C: Some C3H/HeOuJ mice provided by Jackson Laboratory were colonized by Enterobacteriaceae and others were not. Here, fecal counts on days 1 to 8, from Fig 1A are pooled, and represented according to the presence or absence of Enterobacteriaceae prior to oral gavage with <i>E</i>. <i>coli</i> strain 536. The line indicates a significant difference with p<0.01 (t-test). Bars and whiskers represent means ± standard deviation (Fig 1A and B) or median and interquartile range (Fig 1C).</p