Transferrable protection by gut microbes against STING-associated lung disease

STING modulates immunity by responding to bacterial and endogenous cyclic dinucleotides (CDNs). Humans and mice with STING gain-of-function mutations develop a syndrome known as STING-associated vasculopathy with onset in infancy (SAVI), which is characterized by inflammatory or fibrosing lung disease. We hypothesized that hyperresponsiveness of gain-of-function STING to bacterial CDNs might explain autoinflammatory lung disease in SAVI mice. We report that depletion of gut microbes with oral antibiotics (vancomycin, neomycin, and ampicillin [VNA]) nearly eliminates lung disease in SAVI mice, implying that gut microbes might promote STING-associated autoinflammation. However, we show that germ-free SAVI mice still develop severe autoinflammatory disease and that transferring gut microbiota from antibiotics-treated mice to germ-free animals eliminates lung inflammation. Depletion of anaerobes with metronidazole abolishes the protective effect of the VNA antibiotics cocktail, and recolonization with the metronidazole-sensitive anaerobe Bacteroides thetaiotaomicron prevents disease, confirming a protective role of a metronidazole-sensitive microbe in a model of SAVI

Homeostatic interferon-lambda response to bacterial microbiota stimulates preemptive antiviral defense within discrete pockets of intestinal epithelium

Interferon-lambda (IFN-λ) protects intestinal epithelial cells (IECs) from enteric viruses by inducing expression of antiviral IFN-stimulated genes (ISGs). Here, we find that bacterial microbiota stimulate a homeostatic ISG signature in the intestine of specific pathogen-free mice. This homeostatic ISG expression is restricted to IECs, depends on IEC-intrinsic expression of IFN-λ receptor

Intestinal antiviral signaling is controlled by autophagy gene Epg5 independent of the microbiota

Mutations in the macroautophagy/autophagy gen

Glycerol monolaurate prevents mucosal SIV transmission

Although there has been great progress in treating human immunodeficiency virus 1 (HIV-1) infection1, preventing transmission has thus far proven an elusive goal. Indeed, recent trials of a candidate vaccine and microbicide have been disappointing, both for want of efficacy and concerns about increased rates of transmission2–4. Nonetheless, studies of vaginal transmission in the simian immunodeficiency virus (SIV)–rhesus macaque (Macacca mulatta) model point to opportunities at the earliest stages of infection in which a vaccine or microbicide might be protective, by limiting the expansion of infected founder populations at the portal of entry5,6. Here we show in this SIV–macaque model, that an outside-in endocervical mucosal signalling system, involving MIP-3α (also known as CCL20), plasmacytoid dendritic cells and CCR5+ cell-attracting chemokines produced by these cells, in combination with the innate immune and inflammatory responses to infection in both cervix and vagina, recruits CD4+ T cells to fuel this obligate expansion. We then show that glycerol monolaurate—a widely used antimicrobial compound7with inhibitory activity against the production of MIP-3α and other proinflammatory cytokines8—can inhibit mucosal signalling and the innate and inflammatory response to HIV-1 and SIV in vitro, and in vivo it can protect rhesus macaques from acute infection despite repeated intra-vaginal exposure to high doses of SIV. This new approach, plausibly linked to interfering with innate host responses that recruit the target cells necessary to establish systemic infection, opens a promising new avenue for the development of effective interventions to blockHIV-1 mucosal transmission

Alien Invasive Slider Turtle in Unpredicted Habitat: A Matter of Niche Shift or of Predictors Studied?

BACKGROUND: Species Distribution Models (SDMs) aim on the characterization of a species' ecological niche and project it into geographic space. The result is a map of the species' potential distribution, which is, for instance, helpful to predict the capability of alien invasive species. With regard to alien invasive species, recently several authors observed a mismatch between potential distributions of native and invasive ranges derived from SDMs and, as an explanation, ecological niche shift during biological invasion has been suggested. We studied the physiologically well known Slider turtle from North America which today is widely distributed over the globe and address the issue of ecological niche shift versus choice of ecological predictors used for model building, i.e., by deriving SDMs using multiple sets of climatic predictor. PRINCIPAL FINDINGS: In one SDM, predictors were used aiming to mirror the physiological limits of the Slider turtle. It was compared to numerous other models based on various sets of ecological predictors or predictors aiming at comprehensiveness. The SDM focusing on the study species' physiological limits depicts the target species' worldwide potential distribution better than any of the other approaches. CONCLUSION: These results suggest that a natural history-driven understanding is crucial in developing statistical models of ecological niches (as SDMs) while "comprehensive" or "standard" sets of ecological predictors may be of limited use

Glycerol monolaurate prevents mucosal SIV transmission

Although there has been great progress in treating human immunodeficiency virus 1 (HIV-1) infection1, preventing transmission has thus far proven an elusive goal. Indeed, recent trials of a candidate vaccine and microbicide have been disappointing, both for want of efficacy and concerns about increased rates of transmission2–4. Nonetheless, studies of vaginal transmission in the simian immunodeficiency virus (SIV)–rhesus macaque (Macacca mulatta) model point to opportunities at the earliest stages of infection in which a vaccine or microbicide might be protective, by limiting the expansion of infected founder populations at the portal of entry5,6. Here we show in this SIV–macaque model, that an outside-in endocervical mucosal signalling system, involving MIP-3α (also known as CCL20), plasmacytoid dendritic cells and CCR5+ cell-attracting chemokines produced by these cells, in combination with the innate immune and inflammatory responses to infection in both cervix and vagina, recruits CD4+ T cells to fuel this obligate expansion. We then show that glycerol monolaurate—a widely used antimicrobial compound7with inhibitory activity against the production of MIP-3α and other proinflammatory cytokines8—can inhibit mucosal signalling and the innate and inflammatory response to HIV-1 and SIV in vitro, and in vivo it can protect rhesus macaques from acute infection despite repeated intra-vaginal exposure to high doses of SIV. This new approach, plausibly linked to interfering with innate host responses that recruit the target cells necessary to establish systemic infection, opens a promising new avenue for the development of effective interventions to blockHIV-1 mucosal transmission

"I never had the money for blood testing" – Caretakers' experiences of care-seeking for fatal childhood fevers in rural Uganda – a mixed methods study

<p>Abstract</p> <p>Background</p> <p>The main killer diseases of children all manifest as acute febrile illness, yet are curable with timely and adequate management. To avoid a fatal outcome, three essential steps must be completed: caretakers must recognize illness, decide to seek care and reach an appropriate source of care, and then receive appropriate treatment. In a fatal outcome some or all of these steps have failed and it remains to be elucidated to what extent these fatal outcomes are caused by local disease perceptions, inappropriate care-seeking or inadequate resources in the family or health system. This study explores caretakers' experiences of care-seeking for childhood febrile illness with fatal outcome in rural Uganda to elucidate the most influential barriers to adequate care.</p> <p>Methods</p> <p>A mixed methods approach using structured Verbal/Social autopsy interviews and in-depth interviews was employed with 26 caretakers living in Iganga/Mayuge Demographic Surveillance Site who had lost a child 1–59 months old due to acute febrile illness between March and June 2006. In-depth interviews were analysed using content analysis with deductive category application.</p> <p>Results</p> <p>Final categories of barriers to care were: 1) "Illness interpretation barriers" involving children who received delayed or inappropriate care due to caretakers' labelling of the illness, 2) "Barriers to seeking care" with gender roles and household financial constraints hindering adequate care and 3) "Barriers to receiving adequate treatment" revealing discontents with providers and possible deficiencies in quality of care. Resource constraints were identified as the underlying theme for adequate management, both at individual and at health system levels.</p> <p>Conclusion</p> <p>The management of severely ill children in this rural setting has several shortcomings. However, the majority of children were seen by an allopathic health care provider during the final illness. Improvements of basic health care for children suffering from acute febrile illness are likely to contribute to a substantial reduction of fatal outcomes. Health care providers at all levels and private as well as public should receive training, support, equipment and supplies to enable basic health care for children suffering from common illnesses.</p

The Adaptor Molecule Nck Localizes the WAVE Complex to Promote Actin Polymerization during CEACAM3-Mediated Phagocytosis of Bacteria

Background: CEACAM3 is a granulocyte receptor mediating the opsonin-independent recognition and phagocytosis of human-restricted CEACAM-binding bacteria. CEACAM3 function depends on an intracellular immunoreceptor tyrosine-based activation motif (ITAM)-like sequence that is tyrosine phosphorylated by Src family kinases upon receptor engagement. The phosphorylated ITAM-like sequence triggers GTP-loading of Rac by directly associating with the guanine nucleotide exchange factor (GEF) Vav. Rac stimulation in turn is critical for actin cytoskeleton rearrangements that generate lamellipodial protrusions and lead to bacterial uptake. Principal Findings: In our present study we provide biochemical and microscopic evidence that the adaptor proteins Nck1 and Nck2, but not CrkL, Grb2 or SLP-76, bind to tyrosine phosphorylated CEACAM3. The association is phosphorylation-dependent and requires the Nck SH2 domain. Overexpression of the isolated Nck1 SH2 domain, RNAi-mediated knock-down of Nck1, or genetic deletion of Nck1 and Nck2 interfere with CEACAM3-mediated bacterial internalization and with the formation of lamellipodial protrusions. Nck is constitutively associated with WAVE2 and directs the actin nucleation promoting WAVE complex to tyrosine phosphorylated CEACAM3. In turn, dominant-negative WAVE2 as well as shRNA-mediated knock-down of WAVE2 or the WAVE-complex component Nap1 reduce internalization of bacteria. Conclusions: Our results provide novel mechanistic insight into CEACAM3-initiated phagocytosis. We suggest that the CEACAM3 ITAM-like sequence is optimized to co-ordinate a minimal set of cellular factors needed to efficiently trigger actin-based lamellipodial protrusions and rapid pathogen engulfment

In Vivo Conditions to Identify Prkci Phosphorylation Targets Using the Analog-Sensitive Kinase Method in Zebrafish

Protein kinase C iota is required for various cell biological processes including epithelial tissue polarity and organ morphogenesis. To gain mechanistic insight into different roles of this kinase, it is essential to identify specific substrate proteins in their cellular context. The analog-sensitive kinase method provides a powerful tool for the identification of kinase substrates under in vivo conditions. However, it has remained a major challenge to establish screens based on this method in multicellular model organisms. Here, we report the methodology for in vivo conditions using the analog-sensitive kinase method in a genetically-tractable vertebrate model organism, the zebrafish. With this approach, kinase substrates can uniquely be labeled in the developing zebrafish embryo using bulky ATPγS analogs which results in the thiophosphorylation of substrates. The labeling of kinase substrates with a thiophosphoester epitope differs from phosphoesters that are generated by all other kinases and allows for an enrichment of thiophosphopeptides by immunoaffinity purification. This study provides the foundation for using the analog-sensitive kinase method in the context of complex vertebrate development, physiology, or disease