Inhibins Tune the Thymocyte Selection Process by Regulating Thymic Stromal Cell Differentiation

Inhibins and Activins are members of the TGF-β superfamily that regulate the differentiation of several cell types. These ligands were initially identified as hormones that regulate the hypothalamus-pituitary-gonadal axis; however, increasing evidence has demonstrated that they are key regulators in the immune system. We have previously demonstrated that Inhibins are the main Activin ligands expressed in the murine thymus and that they regulate thymocyte differentiation, promoting the DN3-DN4 transition and the selection of SP thymocytes. As Inhibins are mainly produced by thymic stromal cells, which also express Activin receptors and Smad proteins, we hypothesized that Inhibins might play a role in stromal cell differentiation and function. Here, we demonstrate that, in the absence of Inhibins, thymic conventional dendritic cells display reduced levels of MHC Class II (MHCII) and CD86. In addition, the ratio between cTECs and mTECs was affected, indicating that mTEC differentiation was favoured and cTEC diminished in the absence of Inhibins. These changes appeared to impact thymocyte selection leading to a decreased selection of CD4SP thymocytes and increased generation of natural regulatory T cells. These findings demonstrate that Inhibins tune the T cell selection process by regulating both thymocyte and stromal cell differentiation

Treatment with recombinant tissue plasminogen activator (r-TPA) induces neutrophil degranulation in vitro via defined pathways.

AbstractThrombolysis is recommended for reperfusion following acute ischemic stroke (AIS), but its effects on stroke-associated injury remain to be clarified. Here, we investigated the effects of recombinant tissue plasminogen activator (r-tPA) on neutrophil pathophysiology in vitro and in a case–control study with AIS patients submitted (n=60) or not (n=30) to thrombolysis. Patients underwent radiological and clinical examination as well as blood sampling at admission and after 1, 7 and 90days. In vitro, 30-min incubation with 0.1–1mg/ml r-tPA induced neutrophil degranulation in different substrate cultures. Pre-incubation with kinase inhibitors and Western blot documented that degranulation was associated with activation of PI3K/Akt and ERK1/2 pathways in Teflon dishes and PI3K/Akt in polystyrene. In thrombolysed patients, a peak of neutrophil degranulation products (matrix metalloproteinase [MMP]-9, MMP-8, neutrophil elastase and myeloperoxidase), was shown during the first hours from drug administration. This was accompanied by serum augmentation of protective tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2. An increased rate of haemorrhagic transformations on day 1 after AIS was shown in thrombolysed patients as compared to non-thrombolysed controls. In conclusion, r-tPA treatment was associated with in vitro neutrophil degranulation, indicating these cells as potential determinants in early haemorrhagic complications after thrombolysis in AIS patients

Ligand-receptor co-evolution shaped the jasmonate pathway in land plants

The phytohormone jasmonoyl-isoleucine (JA-Ile) regulates defense, growth and developmental responses in vascular plants. Bryophytes have conserved sequences for all JA-Ile signaling pathway components but lack JA-Ile. We show that, in spite of 450 million years of independent evolution, the JA-Ile receptor COI1 is functionally conserved between the bryophyte Marchantia polymorpha and the eudicot Arabidopsis thaliana but COI1 responds to different ligands in each species. We identified the ligand of Marchantia MpCOI1 as two isomeric forms of the JA-Ile precursor dinor-OPDA (dinor-cis-OPDA and dinor-iso-OPDA). We demonstrate that AtCOI1 functionally complements Mpcoi1 mutation and confers JA-Ile responsiveness and that a single-residue substitution in MpCOI1 is responsible for the evolutionary switch in ligand specificity. Our results identify the ancestral bioactive jasmonate and clarify its biosynthetic pathway, demonstrate the functional conservation of its signaling pathway, and show that JA-Ile and COI1 emergence in vascular plants required co-evolution of hormone biosynthetic complexity and receptor specificity

The MHC Gene Region of Murine Hosts Influences the Differential Tissue Tropism of Infecting Trypanosoma cruzi Strains

We have previously demonstrated that both parasite genetic variability and host genetic background were important in determining the differential tissue distribution of the Col1.7G2 and JG T. cruzi monoclonal strains after artificial infections in mice. We observed that the JG strain was most prevalent in hearts of mouse lineages with the MHC haplotype H-2d (BALB/c and DBA2), while Col1.7G2 was predominant in hearts from C57BL/6 mice, which have the H-2b haplotype. To assess whether the MHC gene region indeed influenced tissue tropism of T. cruzi, we used the same two parasite strains to infect C57BL/6 (H-2b) and C57BLKS/J (H-2d) mice; the latter strain results from the introgression of DBA2 MHC region into the C57BL/6 background. We also performed ex vivo infections of cardiac explants from four congenic mice lineages with the H-2b and H-2d haplotypes arranged in two different genetic backgrounds: C57BLKS/J (H-2d) versus C57BL/6 (H-2b) and BALB/c (H-2d) versus BALB/B10-H2b (H-2b). In agreement with our former observations, Col1.7G2 was predominant in hearts from C57BL/6 mice (H-2b), but we observed a clear predominance of the JG strain in hearts from C57BLKS/J animals (H-2d). In the ex vivo experiments Col1.7G2 also prevailed in explants from H-2b animals while no predominance of any of the strains was observed in H-2d mice explants, regardless of the genetic background. These observations clearly demonstrate that the MHC region influences the differential tissue distribution pattern of infecting T. cruzi strains, which by its turn may be in a human infection the determinant for the clinical forms of the Chagas disease

Genetically-Determined Hyperfunction of the S100B/RAGE Axis Is a Risk Factor for Aspergillosis in Stem Cell Transplant Recipients

Invasive aspergillosis (IA) is a major threat to the successful outcome of hematopoietic stem cell transplantation (HSCT), although individual risk varies considerably. Recent evidence has established a pivotal role for a danger sensing mechanism implicating the S100B/receptor for advanced glycation end products (RAGE) axis in antifungal immunity. The association of selected genetic variants in the S100B/RAGE axis with susceptibility to IA was investigated in 223 consecutive patients undergoing HSCT. Furthermore, studies addressing the functional consequences of these variants were performed. Susceptibility to IA was significantly associated with two distinct polymorphisms in RAGE (-374T/A) and S100B (+427C/T) genes, the relative contribution of each depended on their presence in both transplantation counterparts [patient SNPRAGE, adjusted hazard ratio (HR), 1.97; P = 0.042 and donor SNPRAGE, HR, 2.03; P = 0.047] or in donors (SNPS100B, HR, 3.15; P = 7.8e-4) only, respectively. Functional assays demonstrated a gain-of-function phenotype of both variants, as shown by the enhanced expression of inflammatory cytokines in RAGE polymorphic cells and increased S100B secretion in vitro and in vivo in the presence of the S100B polymorphism. These findings point to a relevant role of the danger sensing signaling in human antifungal immunity and highlight a possible contribution of a genetically-determined hyperfunction of the S100B/RAGE axis to susceptibility to IA in the HSCT setting

Advancing One Health:Updated core competencies

International audienceAbstract One Health recognises the interdependence between the health of humans, animals, plants and the environment. With the increasing inclusion of One Health in multiple global health strategies, the One Health workforce must be prepared to protect and sustain the health and well-being of life on the planet. In this paper, a review of past and currently accepted One Health core competencies was conducted, with competence gaps identified. Here, the Network for Ecohealth and One Health (NEOH) propose updated core competencies designed to simplify what can be a complex area, grouping competencies into three main areas of: Skills; Values and Attitudes; and Knowledge and Awareness; with several layers underlying each. These are intentionally applicable to stakeholders from various sectors and across all levels to support capacity-building efforts within the One Health workforce. The updated competencies from NEOH can be used to evaluate and enhance current curricula, create new ones, or inform professional training programs at all levels, including students, university teaching staff, or government officials as well as continual professional development for frontline health practitioners and policy makers. The competencies are aligned with the new definition of One Health developed by the One Health High-Level Expert Panel (OHHLEP), and when supported by subjectspecific expertise, will deliver the transformation needed to prevent and respond to complex global challenges. One Health Impact Statement Within a rapidly changing global environment, the need for practitioners competent in integrated approaches to health has increased substantially. Narrow approaches may not only limit opportunities for global and local solutions but, initiatives that do not consider other disciplines or social, economic and cultural contexts, may result in unforeseen and detrimental consequences. In keeping with principles of One Health, the Network for Ecohealth and One Health (NEOH) competencies entail a collaborative effort between multiple disciplines and sectors. They focus on enabling practitioners, from any background, at any level or scale of involvement, to promote and support a transformation to integrated health approaches. The updated competencies can be layered with existing disciplinary competencies and used to evaluate and enhance current education curricula, create new ones, or inform professional training programs at all levels-including for students, teachers and government officials as well as continual professional development for frontline health practitioners and policymakers. The competencies outlined here are applicable to all professionals and disciplines who may contribute to One Health, and are complimentary to, not a replacement for, any discipline-specific competencies. We believe the NEOH competencies meet the need outlined by the Quadripartite’s (Food and Agriculture Organisation, United Nations Environment Programme, World Health Organisation, World Organisation for Animal Health) Joint Plan of Action on One Health which calls for cross-sectoral competencies

Guidelines and mindlines: why do clinical staff over-diagnose malaria in Tanzania? A qualitative study

BACKGROUND: Malaria over-diagnosis in Africa is widespread and costly both financially and in terms of morbidity and mortality from missed diagnoses. An understanding of the reasons behind malaria over-diagnosis is urgently needed to inform strategies for better targeting of antimalarials. METHODS: In an ethnographic study of clinical practice in two hospitals in Tanzania, 2,082 patient consultations with 34 clinicians were observed over a period of three months at each hospital. All clinicians were also interviewed individually as well as being observed during routine working activities with colleagues. Interviews with five tutors and 10 clinical officer students at a nearby clinical officer training college were subsequently conducted. RESULTS: Four, primarily social, spheres of influence on malaria over-diagnosis were identified. Firstly, the influence of initial training within a context where the importance of malaria is strongly promoted. Secondly, the influence of peers, conforming to perceived expectations from colleagues. Thirdly, pressure to conform with perceived patient preferences. Lastly, quality of diagnostic support, involving resource management, motivation and supervision. Rather than following national guidelines for the diagnosis of febrile illness, clinician behaviour appeared to follow 'mindlines': shared rationales constructed from these different spheres of influence. Three mindlines were identified in this setting: malaria is easier to diagnose than alternative diseases; malaria is a more acceptable diagnosis; and missing malaria is indefensible. These mindlines were apparent during the training stages as well as throughout clinical careers. CONCLUSION: Clinicians were found to follow mindlines as well as or rather than guidelines, which incorporated multiple social influences operating in the immediate and the wider context of decision making. Interventions to move mindlines closer to guidelines need to take the variety of social influences into account