Mycobacterial lipoarabinomannans modulate cytokine production in human T helper cells by interfering with raft/microdomain signalling

Abstract.: Lipoarabinomannans (LAMs) are major lipoglycans of the mycobacterial envelope and constitute immunodominant epitopes of mycobacteria. In this paper, we show that mannose-capped (ManLAM) and non-mannose- capped (PILAM) mycobacterial lipoglycans insert into T helper cell rafts without apparent binding to known receptors. T helper cells modified by the insertion of PILAM responded to CD3 cross-linking by decreasing type 1 (IL-2 and IFN-γ) and increasing type 2 (IL-4 and IL-5) cytokine production. Modification by the mannose-capped ManLAMs had similar, but more limited effects on T helper cell cytokine production. When incorporated into isolated rafts, PILAMs modulated membrane-associated kinases in a dose-dependent manner, inducing increased phosphorylation of Src kinases and Cbp/PAG in Th1 rafts, while decreasing phosphorylation of the same proteins in Th2 rafts. Mycobacterial lipoglycans thus modify the signalling machineries of rafts/microdomains in T helper cells, a modification of the membrane organization that eventually leads to an overall enhancement of type 2 and inhibition of type 1 cytokine productio

Locating Functionalized Gold Nanoparticles Using Electrical Impedance Tomography

Abstract Objective: An imaging device to locate functionalized nanoparticles, whereby therapeutic agents are transported from the site of administration specifically to diseased tissues, remains a challenge for pharmaceutical research. Here, we show a new method based on electrical impedance tomography (EIT) to provide images of the location of gold nanoparticles (GNPs) and the excitation of GNPs with radio frequencies (RF) to change impedance permitting an estimation of their location in cell models Methods: We have created an imaging system using quantum cluster GNPs as a contrast agent, activated with RF fields to heat the functionalized GNPs, which causes a change in impedance in the surrounding region. This change is then identified with EIT. Results: Images of impedance changes of around 804% are obtained for a sample of citrate stabilized GNPs in a solution of phosphate-buffered saline. A second quantification was carried out using colorectal cancer cells incubated with culture media, and the internalization of GNPs into the colorectal cancer cells was undertaken to compare them with the EIT images. When the cells were incubated with functionalized GNPs, the change was more apparent, approximately 402%. This change was reflected in the EIT image as the cell area was more clearly identifiable from the rest of the area. Significance: EIT can be used as a new method to locate functionalized GNPs in human cells and help in the development of GNP-based drugs in humans to improve their efficacy in the future

Development and application of a 2-step methodology to select a reference society providing Dietary Reference Values for national implementation

Objective: To describe and discuss a 2-step methodology developed to select a reference society that provides Dietary Reference Values (DRVs) for national implementation and to illustrate its application in Switzerland with one macronutrient and one micronutrient.Design: During Step 1, we searched and compared DRVs and methodologies used to define DRVs from eight European societies for seven selected nutrients. We repeated this procedure during Step 2 for DRVs from two preselected societies for 44 nutrients.Setting: The 2-step methodology applied here for Switzerland may be used in other countriesParticipants: The research team commissioned six external experts from three linguistic regions of Switzerland, who provided their opinions through two online surveys, individual interviews, and a focus group.Results: After Step 1, we excluded five societies because of old publication dates, irrelevant publication languages for Switzerland, difficulty in accessing documents, or because their DRVs were mainly based on another society. After Step 2, the two societies were qualified based on the analysis of the values and methodologies used. The need for free and easily accessible scientific background information favored the European Food Safety Authority (EFSA). We chose alternative societies for nine nutrients for the overall population or subgroups, and for elderly.Conclusions: To manage heterogeneous and complex data from several societies, adopting a 2-step methodology including fewer nutrients and more societies during Step 1, and fewer societies but all nutrients in Step 2, was very helpful. With some exceptions, we selected EFSA as the main society to provide DRVs for Switzerland

Human rights and community work. Complementary theories and practices

Much effort has been placed on developing international understandings of human rights without the corresponding attention to responsibilities. The authors argue that a community development framework may be useful in re-conceiving human rights in a more holistic way, and that social workers and community development workers are well placed to be 'grass roots human rights workers

Long Lasting Local and Systemic Inflammation after Cerebral Hypoxic ischemia in Newborn Mice

Background: Hypoxic ischemia (HI) is an important cause of neonatal brain injury and subsequent inflammation affects neurological outcome. In this study we performed investigations of systemic and local activation states of inflammatory cells from innate and adaptive immunity at different time points after neonatal HI brain injury in mice. Methodology/Principal Findings: We developed a multiplex flow cytometry based method combined with immunohistochemistry to investigate cellular immune responses in the brain 24 h to 7 months after HI brain injury. In addition, functional studies of ex vivo splenocytes after cerebral hypoxic ischemia were performed. Both central and peripheral activation of CD11b + and CD11c + antigen presenting cells were seen with expression of the costimulatory molecule CD86 and MHC-II, indicating active antigen presentation in the damaged hemisphere and in the spleen. After one week, naïve CD45rb + T-lymphocytes were demonstrated in the damaged brain hemisphere. In a second phase after three months, pronounced activation of CD45rb 2 T-lymphocytes expressing CD69 and CD25 was seen in the damaged hemisphere. Brain homogenate induced proliferation in splenocytes after HI but not in controls. Conclusions/Significance: Our findings demonstrate activation of both local and systemic immune responses months after hypoxic ischemic neonatal brain injury. The long term immune activation observed is of general importance for future studies of the inflammatory response after brain injury as most previous studies have focused on the first few weeks afte

Identification of Novel Antimalarial Chemotypes via Chemoinformatic Compound Selection Methods for a High-Throughput Screening Program against the Novel Malarial Target, PfNDH2: Increasing Hit Rate via Virtual Screening Methods

Malaria is responsible for approximately 1 million deaths annually; thus, continued efforts to discover new antimalarials are required. A HTS screen was established to identify novel inhibitors of the parasite's mitochondrial enzyme NADH:quinone oxidoreductase (PfNDH2). On the basis of only one known inhibitor of this enzyme, the challenge was to discover novel inhibitors of PfNDH2 with diverse chemical scaffolds. To this end, using a range of ligand-based chemoinformatics methods, ~17000 compounds were selected from a commercial library of ~750000 compounds. Forty-eight compounds were identified with PfNDH2 enzyme inhibition IC(50) values ranging from 100 nM to 40 μM and also displayed exciting whole cell antimalarial activity. These novel inhibitors were identified through sampling 16% of the available chemical space, while only screening 2% of the library. This study confirms the added value of using multiple ligand-based chemoinformatic approaches and has successfully identified novel distinct chemotypes primed for development as new agents against malaria

CD4CD8αα Lymphocytes, A Novel Human Regulatory T Cell Subset Induced by Colonic Bacteria and Deficient in Patients with Inflammatory Bowel Disease

It has become evident that bacteria in our gut affect health and disease, but less is known about how they do this. Recent studies in mice showed that gut Clostridium bacteria and their metabolites can activate regulatory T cells (Treg) that in turn mediate tolerance to signals that would ordinarily cause inflammation. In this study we identify a subset of human T lymphocytes, designated CD4CD8αα T cells that are present in the surface lining of the colon and in the blood. We demonstrate Treg activity and show these cells to be activated by microbiota; we identify F. prausnitzii, a core Clostridium strain of the human gut microbiota, as a major inducer of these Treg cells. Interestingly, there are fewer F. prausnitzii in individuals suffering from inflammatory bowel disease (IBD), and accordingly the CD4CD8αα T cells are decreased in the blood and gut of patients with IBD. We argue that CD4CD8αα colonic Treg probably help control or prevent IBD. These data open the road to new diagnostic and therapeutic strategies for the management of IBD and provide new tools to address the impact of the intestinal microbiota on the human immune system