Pathogen-Mediated Inhibition of Anorexia Promotes Host Survival and Transmission.

Sickness-induced anorexia is a conserved behavior induced during infections. Here, we report that an intestinal pathogen, Salmonella Typhimurium, inhibits anorexia by manipulating the gut-brain axis. Inhibition of inflammasome activation by the S. Typhimurium effector, SlrP, prevented anorexia caused by IL-1ß-mediated signaling to the hypothalamus via the vagus nerve. Rather than compromising host defenses, pathogen-mediated inhibition of anorexia increased host survival. SlrP-mediated inhibition of anorexia prevented invasion and systemic infection by wild-type S. Typhimurium, reducing virulence while increasing transmission to new hosts, suggesting that there are trade-offs between transmission and virulence. These results clarify the complex and contextual role of anorexia in host-pathogen interactions and suggest that microbes have evolved mechanisms to modulate sickness-induced behaviors to promote health of their host and their transmission at the expense of virulence.

Resistance and tolerance defenses in cancer: Lessons from infectious diseases.

Infectious disease and cancer are two maladies with multiple similarities. Both types of disease induce activation of the host immune response and induce pathologies that compromise host heath and survival. In infection biology, defense against pathogens can be broken down into two distinct components called resistance and tolerance. Resistance protects the host by killing pathogens. Tolerance protects the host by alleviating the pathology caused by the infection. The conceptual framework of resistance and tolerance, concepts explored during infectious disease, is applicable to cancer, a condition for which patient survival is dependent on tumor eradication (resistance) and the mitigation of pathologies that occur during disease (tolerance). Here, we propose that integration of the concept of disease tolerance into cancer studies will result in new therapies to complement current resistance-based treatment strategies to increase the likelihood of patient survival and to improve quality of life. Furthermore, by drawing parallels between infectious disease and cancer, we propose that host interactions with microbes could provide therapeutic insight for promoting tolerance defense and focus our discussion on cachexia, a pathology resulting in significant morbidity in cancer patients.

Whose feminism(s)? Overseas partner organizations' perceptions of Canada's Feminist International Assistance Policy.

Canada's Feminist International Assistance Policy, introduced in 2017, is an ambitious and forward-thinking policy focussed on gender equality and women's empowerment. The emphasis on a feminist vision, however, raises questions about how feminism is defined and interpreted by Canada's partners in the Global South. In this article, we examine the interpretations of feminism(s) and a feminist foreign policy from the perspective of NGO staff members in East and Southern Africa. The research involved interviews with 45 Global South partner country NGO staff members in three countries (Kenya, Uganda, and Malawi). We consider the partner organization reflections on Canada's Feminist International Assistance Policy using a transnational feminist lens. Our findings provide insights into future considerations for Canada's feminist foreign policy priorities, consultations, and programme design.

ST2 contributes to T-cell hyperactivation and fatal hemophagocytic lymphohistiocytosis in mice.

Cytokine storm syndromes, such as familial hemophagocytic lymphohistiocytosis (FHL), are lethal disorders caused by uncontrolled, systemic immune activation. In the murine model of FHL, in which perforin-deficient (Prf1(-/-)) mice are infected with lymphocytic choriomeningitis virus (LCMV), disease is driven by overabundant interferon (IFN)γ-producing LCMV-specific CD8(+) T cells thought to arise from excessive antigen stimulation through the T-cell receptor. However, this paradigm is insufficient to explain several fundamental aspects of FHL, namely, the inability of many pathogenic antigens to induce hyperinflammation, and the previously identified role of MyD88 in the disease. We now show a novel role for the MyD88-dependent interleukin-33 (IL-33) receptor, ST2, in FHL. Expression of IL-33 and ST2 is upregulated in LCMV-infected Prf1(-/-) mice. Blockade of ST2 markedly improves survival of LCMV-infected Prf1(-/-) mice and reduces the severity of multiple disease parameters, including serum levels of IFNγ. This decrease in IFNγ corresponds to a reduction in both the frequency of IFNγ(+) LCMV-specific CD8(+) and CD4(+) T cells and the magnitude of IFNγ expression in these cells. These findings demonstrate that disruption of ST2 signaling in the murine model of FHL reduces T cell-mediated production of IFNγ and suggest a revised paradigm in which danger signals such as IL-33 are crucial amplifiers of immune dysregulation in FHL. Furthermore, this study provides evidence to support blockade of ST2 as a novel therapeutic strategy for FHL.

Spleen tyrosine kinase (Syk)-dependent calcium signals mediate efficient CpG-induced exocytosis of tumor necrosis factor α (TNFα) in innate immune cells.

Pattern recognition receptors expressed by cells of the innate immune system initiate the immune response upon recognition of microbial products. Activation of pattern recognition receptors result in the production and release of proinflammatory cytokines, including TNFα and IL-6. Because these cytokines promote disparate effector cell responses, understanding the signaling pathways involved in their regulation is critical for directing the immune response. Using macrophages and dendritic cells deficient in spleen tyrosine kinase (Syk), we identified a novel pathway by which TNFα trafficking and secretion are regulated by Syk following stimulation with CpG DNA. In the absence of PLCγ2, a Syk substrate, or the calcium-responsive kinase calcium calmodulin kinase II, CpG-induced TNFα secretion was impaired. Forced calcium mobilization rescued the TNFα secretion defect in Syk-deficient cells. In contrast to its effect on TNFα, Syk deficiency did not affect IL-6 secretion, suggesting that Syk-dependent signals participate in differential sorting of cytokines, thus tailoring the cytokine response. Our data report a novel pathway for TNFα regulation and provide insight into non-transcriptional mechanisms for shaping cytokine responses.

A subset of FG-nucleoporins is necessary for efficient Msn5-mediated nuclear protein export.

The transport of proteins between the cytoplasm and nucleus requires interactions between soluble transport receptors (karyopherins) and phenylalanine-glycine (FG) repeat domains on nuclear pore complex proteins (nucleoporins). However, the role of specific FG repeat-containing nucleoporins in nuclear protein export has not been carefully investigated. We have developed a novel kinetic assay to investigate the relative export kinetics mediated by the karyopherin Msn5/Kap142 in yeast containing specific FG-Nup mutations. Using the Msn5 substrate Crz1 as a marker for Msn5-mediated protein export, we observe that deletions of NUP100 or NUP2 result in decreased rates of Crz1 export, while nup60Δ and nup42Δ mutants do not vary significantly from wild type. The decreased Msn5 export rate in nup100Δ was confirmed using Mig1-GFP as a transport substrate. A nup100ΔGLFG mutant shows defects in nuclear export kinetics similar to a nup100Δ deletion. Removal of FG-repeats from Nsp1 also decreases export kinetics, while a loss of Nup1 FXFGs does not. To confirm that our export data reflected functional differences in protein localization, we performed Crz1 transcription activation assays using a CDRE::LacZ reporter gene that is upregulated upon increased transcription activation by Crz1 in vivo. We observe that expression from this reporter increases in nup100ΔGLFG and nsp1ΔFGΔFXFG strains that exhibit decreased Crz1 export kinetics but resembles wild-type levels in nup1ΔFXFG strains that do not exhibit export defects. These data provide evidence that the export of Msn5 is likely mediated by a specific subset of FG-Nups and that the GLFG repeat domain of Nup100 is important for Msn5-mediated nuclear protein export.

Nourishing the Nexus: A Feminist Analysis of Gender, Nutrition and Agri-food Development Policies and Practices.

This article applies feminist critiques to investigate how agri-food and nutritional development policy and interventions address gender inequality. Based on the analysis presented of global policies and examples of project experiences from Haiti, Benin, Ghana, and Tanzania, we find that the widespread emphasis on gender equality in policy and practice generally ascribes to a gender narrative that includes static, homogenized conceptualizations of food provisioning and marketing. These narratives tend to translate to interventions that instrumentalize women's labor by funding their income generating activities and care responsibilities for other benefits like household food and nutrition security without addressing underlying structures that cause their vulnerability, such as disproportionate work burdens, land access challenges, among many others. We argue that policy and interventions must prioritize locally contextualized social norms and environmental conditions, and consider further the way wider policies and development assistance shape social dynamics to address the structural causes of gender and intersecting inequalities.

Cet article se sert des critiques féministes pour étudier la façon dont les politiques et les interventions de développement agroalimentaire et nutritionnel traitent l'inégalité entre les sexes. Sur la base de l'analyse présentée des politiques mondiales et des exemples d'expériences de projets en Haïti, au Bénin, au Ghana et en Tanzanie, nous constatons que l'accent généralisé sur l'égalité des sexes dans les politiques et les pratiques attribue généralement à un récit de genre qui comprend des conceptualisations statiques et homogénéisées de l'approvisionnement et de la commercialisation des denrées alimentaires. Ces récits ont tendance à se traduire par des interventions qui instrumentalisent le travail des femmes en finançant leurs activités génératrices de revenus et leurs responsabilités de soins à fins telles que la sécurité alimentaire et nutritionnelle des ménages, sans pour autant s'attaquer aux structures sous-jacentes qui causent leur vulnérabilité, telles que les charges de travail disproportionnées, les difficultés d'accès à la terre, parmi tant d'autres. Nous soutenons que les politiques et les interventions doivent donner la priorité aux normes sociales et aux conditions environnementales contextualisées localement, et mieux prendre en compte la manière dont les politiques publiques en général et l'aide au développement façonnent la dynamique sociale pour s'attaquer aux causes structurelles des inégalités de genre et croisées.

Cutting edge: bortezomib-treated tumors sensitized to NK cell apoptosis paradoxically acquire resistance to antigen-specific T cells.

Bortezomib augments caspase-8 activity, rendering tumors susceptible to NK cell lysis. We hypothesized this effect would likewise sensitize tumors to Ag-specific CTLs. Instead, bortezomib-treated tumors that acquired sensitivity to NK cells simultaneously became resistant to killing by Ag-specific CTLs. Reduction in CTL killing persisted for days, was not due to changes in tumor expression of MHC class I, and was overcome by pulsing tumors with peptides recognized by tumor-reactive CTLs. Tumor-outgrowth experiments showed tumors grew faster in SCID mice when cocultures of tumor-reactive CTLs and bortezomib-treated tumors were injected compared with untreated tumors (tumor doubling time 3.1 and 10.6 d, respectively; p < 0.01), whereas tumors grew slower in mice receiving cocultures of NK cells and bortezomib-treated tumors compared with untreated tumors (11.8 d and 5.0 d, respectively; p < 0.01). These findings demonstrate bortezomib-treated tumors sensitized to NK cell apoptosis paradoxically acquire resistance to CTLs as a consequence of bortezomib altering proteasomal processing and presentation of tumor Ags.

A pilot study evaluating the safety and CD34+ cell mobilizing activity of escalating doses of plerixafor in healthy volunteers.

This study evaluated the safety and CD34+ cell mobilizing activity of escalating doses of plerixafor in healthy volunteers. Three cohorts of six subjects received two different doses of plerixafor separated by at least 2 weeks to allow for adequate pharmacodynamic wash-out. The following dosing cohorts were evaluated: 0·24 and 0·32 mg/kg (Cohort 1); 0·32 and 0·40 mg/kg (Cohort 2); and 0·40 and 0·48 mg/kg (Cohort 3). Circulating CD34+ cells were measured 0, 2, 4, 6, 8, 10, 12, 14, 18 and 24 h after each dose. Blood colony-forming units were measured at baseline and 6 h after each dose. Common adverse events were diarrhoea, injection site erythema, perioral numbness, sinus tachycardia, headache, nausea, abdominal distention and injection site pain. No dose limiting toxicities occurred. When higher doses of plerixafor were administered, there was a trend towards higher peak CD34+ counts and CD34+ area under the curves, although these differences did not achieve statistical significance, perhaps due to intra-subject variability. Together, these data show that the higher doses of plerixafor evaluated in this study are reasonably safe and suggest that a larger study should be performed to definitively answer whether increased numbers of CD34+ cell are mobilized with higher doses of plerixafor.

Tyrosine 870 of TLR9 is critical for receptor maturation rather than phosphorylation-dependent ligand-induced signaling.

Toll like receptors (TLRs) share a conserved structure comprising the N-terminal ectodomain, a transmembrane segment and a C-terminal cytoplasmic Toll/IL-1 receptor (TIR) domain. Proper assembly of the TIR domain is crucial for signal transduction; however, the contribution of individual motifs within the TIR domain to TLR trafficking and signaling remains unclear. We targeted a highly conserved tyrosine (Y870) located in the box 1 region of the TIR domain of most TLRs, including TLR9, previously described to be a critical site of phosphorylation in TLR4. We reconstituted bone marrow-derived dendritic cells (BMDC) from Tlr9-/- mice WT TLR9 or Y870F or Y870A mutants. Despite normal interactions with the luminal chaperones GRP94 and UNC93B1, Y870F conferred only partial responsiveness to CpG, and Y870A had no activity and functioned as a dominant negative inhibitor when coexpressed with endogenous TLR9. This loss of function correlated with reduction or absence, respectively, of the 80 kDa mature form of TLR9. In Y870F-expressing cells, CpG-dependent signaling correlated directly with levels of the mature form, suggesting that signaling did not require tyrosine phosphorylation but rather that the Y870F mutation conferred reduced receptor levels due to defective processing or trafficking. Microscopy revealed targeting of the mutant protein to an autophagolysosome-like structure for likely degradation. Collectively we postulate that the conserved Y870 in the TIR domain does not participate in phosphorylation-induced signaling downstream of ligand recognition, but rather is crucial for proper TIR assembly and ER egress, resulting in maturation-specific stabilization of TLR9 within endolysosomes and subsequent pro-inflammatory signaling.

Repeated TLR9 stimulation results in macrophage activation syndrome-like disease in mice.

Hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) are 2 similar diseases characterized by a cytokine storm, overwhelming inflammation, multiorgan dysfunction, and death. Animal models of HLH suggest that disease is driven by IFN-γ produced by CD8⁺ lymphocytes stimulated by persistent antigen exposure. In these models and patients with "primary" HLH, the antigen persists due to genetic defects, resulting in ineffective cytotoxic responses by CD8⁺ T cells and poor pathogen clearance. However, infectious triggers are often not identified in patients with MAS, and some patients with HLH or MAS lack defects in cytotoxic T cell killing. Herein, we show that repeated stimulation of TLR9 produced an HLH/MAS-like syndrome on a normal genetic background, without exogenous antigen. Like previous HLH models, TLR9-induced MAS was IFN-γ dependent; however, unlike other models, disease did not require lymphocytes. We further showed that IL-10 played a protective role in this model and that blocking IL-10 signaling led to the development of hemophagocytosis. IL-10 may therefore be an important target for the development of effective therapeutics for MAS. Our data provide insight into MAS-like syndromes in patients with inflammatory diseases in which there is chronic innate immune activation but no genetic defects in cytotoxic cell function.

Influence of body position and stool characteristics on defecation in humans.

BACKGROUND: Whether defecation is influenced by body position or stool characteristics is unclear. AIM: We investigated effects of body position, presence of stool-like sensation, and stool form on defecation patterns and manometric profiles. METHODS: Rectal and anal pressures were assessed in 25 healthy volunteers during attempted defecation either in the lying or sitting positions and with balloon-filled or empty rectum. Subjects also expelled a water-filled (50 cc) balloon or silicone-stool (FECOM) either lying or sitting and rated their stooling sensation. RESULTS: When attempting to defecate in the lying position, a dyssynergic pattern was seen in 36% of subjects with empty rectum and 24% with distended rectum. When sitting, 20% showed dyssynergia with empty rectum and 8% with distended rectum. More subjects (p < 0.05) showed dyssynergia in lying position. When lying, 60% could not expel balloon and 44% FECOM. When sitting, fewer (p < 0.05) failed to expel balloon (16%) or FECOM (4%). FECOM expulsion time was quicker (p < 0.02). Stool-like sensation was more commonly (p < 0.005) evoked by FECOM than balloon. CONCLUSIONS: In the lying position, one-third showed dyssynergia and one-half could not expel artificial stool. Whereas when sitting with distended rectum, most showed normal defecation pattern and ability to expel stool. Thus, body position, sensation of stooling and stool characteristics may each influence defecation. Defecation is best evaluated in the sitting position with artificial stool.