Suppression of Arabidopsis protophloem differentiation and root meristem growth by CLE45 requires the receptor-like kinase BAM3.

Peptide signaling presumably occupies a central role in plant development, yet only few concrete examples of receptor-ligand pairs that act in the context of specific differentiation processes have been described. Here we report that second-site null mutations in the Arabidopsis leucine-rich repeat receptor-like kinase gene barely any meristem 3 (BAM3) perfectly suppress the postembryonic root meristem growth defect and the associated perturbed protophloem development of the brevis radix (brx) mutant. The roots of bam3 mutants specifically resist growth inhibition by the CLAVATA3/ENDOSPERM SURROUNDING REGION 45 (CLE45) peptide ligand. WT plants transformed with a construct for ectopic overexpression of CLE45 could not be recovered, with the exception of a single severely dwarfed and sterile plant that eventually died. By contrast, we obtained numerous transgenic bam3 mutants transformed with the same construct. These transgenic plants displayed a WT phenotype, however, supporting the notion that CLE45 is the likely BAM3 ligand. The results correlate with the observation that external CLE45 application represses protophloem differentiation in WT, but not in bam3 mutants. BAM3, BRX, and CLE45 are expressed in a similar spatiotemporal trend along the developing protophloem, up to the end of the transition zone. Induction of BAM3 expression upon CLE45 application, ectopic overexpression of BAM3 in brx root meristems, and laser ablation experiments suggest that intertwined regulatory activity of BRX, BAM3, and CLE45 could be involved in the proper transition of protophloem cells from proliferation to differentiation, thereby impinging on postembryonic growth capacity of the root meristem.

Fast subplasma membrane Ca2+ transients control exo-endocytosis of synaptic-like microvesicles in astrocytes

Astrocytes are the most abundant glial cell type in the brain. Although not apposite for long-range rapid electrical communication, astrocytes share with neurons the capacity of chemical signaling via Ca(2+)-dependent transmitter exocytosis. Despite this recent finding, little is known about the specific properties of regulated secretion and vesicle recycling in astrocytes. Important differences may exist with the neuronal exocytosis, starting from the fact that stimulus-secretion coupling in astrocytes is voltage independent, mediated by G-protein-coupled receptors and the release of Ca(2+) from internal stores. Elucidating the spatiotemporal properties of astrocytic exo-endocytosis is, therefore, of primary importance for understanding the mode of communication of these cells and their role in brain signaling. We here take advantage of fluorescent tools recently developed for studying recycling of glutamatergic vesicles at synapses (Voglmaier et al., 2006; Balaji and Ryan, 2007); we combine epifluorescence and total internal reflection fluorescence imaging to investigate with unprecedented temporal and spatial resolution, the stimulus-secretion coupling underlying exo-endocytosis of glutamatergic synaptic-like microvesicles (SLMVs) in astrocytes. Our main findings indicate that (1) exo-endocytosis in astrocytes proceeds with a time course on the millisecond time scale (tau(exocytosis) = 0.24 +/- 0.017 s; tau(endocytosis) = 0.26 +/- 0.03 s) and (2) exocytosis is controlled by local Ca(2+) microdomains. We identified submicrometer cytosolic compartments delimited by endoplasmic reticulum tubuli reaching beneath the plasma membrane and containing SLMVs at which fast (time-to-peak, approximately 50 ms) Ca(2+) events occurred in precise spatial-temporal correlation with exocytic fusion events. Overall, the above characteristics of transmitter exocytosis from astrocytes support a role of this process in fast synaptic modulation.

Identification of casein kinase 1, casein kinase 2, and cAMP-dependent protein kinase-like activities in Trypanosoma evansi

Trypanosoma evansi contains protein kinases capable of phosphorylating endogenous substrates with apparent molecular masses in the range between 20 and 205 kDa. The major phosphopolypeptide band, pp55, was predominantly localized in the particulate fraction. Anti-alpha and anti-beta tubulin monoclonal antibodies recognized pp55 by Western blot analyses, suggesting that this band corresponds to phosphorylated tubulin. Inhibition experiments in the presence of emodin, heparin, and 2,3-bisphosphoglycerate indicated that the parasite tubulin kinase was a casein kinase 2 (CK2)-like activity. GTP, which can be utilized instead of ATP by CK2, stimulated rather than inactivated the phosphorylation of tubulin in the parasite homogenate and particulate fraction. However, GTP inhibited the cytosolic CK2 responsible for phosphorylating soluble tubulin and other soluble substrates. Casein and two selective peptide substrates, P1 (RRKDLHDDEEDEAMSITA) for casein kinase (CK1) and P2 (RRRADDSDDDDD) for CK2, were recognized as substrates in T. evansi. While the enzymes present in the soluble fraction predominantly phosphorylated P1, P2 was preferentially labeled in the particulate fractions. These results demonstrated the existence of CK1-like and CK2-like activities primarily located in the parasite cytosolic and membranous fractions, respectively. Histone II-A and kemptide (LRRASVA) also behaved as suitable substrates, implying the existence of other Ser/Thr kinases in T. evansi. Cyclic AMP only increased the phosphorylation of histone II-A and kemptide in the cytosol, demonstrating the existence of soluble cAMP-dependent protein kinase-like activities in T. evansi. However, no endogenous substrates for this enzyme were identified in this fraction. Further evidences were obtained by using PKI (6-22), a reported inhibitor of the catalytic subunit of mammalian cAMP-dependent protein kinases, which specifically hindered the cAMP-dependent phosphorylation of histone II-A and kemptide in the parasite soluble fraction. Since the sum of the values obtained in the parasite cytosolic and particulate fractions were always higher than the values observed in the total T. evansi lysate, the kinase activities examined here appeared to be inhibited in the original extract.

Public Policy and Ageing in Northern Ireland: Identifying Levers for Change

Public Policy and Ageing in Northern Ireland: Identifying Levers for Change Judith Cross, Policy Officer with the Centre for Ageing Research Development in Ireland (CARDI)��������Introduction Identifying a broad range of key public policy initiatives as they relate to age can facilitate discussion and create new knowledge within and across government to maximise the opportunities afforded by an ageing population. This article looks at how examining the current public policy frameworks in Northern Ireland can present opportunities for those working in this field for the benefit of older people. Good policy formulation needs to be evidence-based, flexible, innovative and look beyond institutional boundaries. Bringing together architects and occupational therapists, for example, has the potential to create better and more effective ways relevant to health, housing, social services and government departments. Traditional assumptions of social policy towards older people have tended to be medically focused with an emphasis on care and dependency. This in turn has consequences for the design and delivery of services for older people. It is important that these assumptions are challenged as changes in thinking and attitudes can lead to a redefinition of ageing, resulting in policies and practices that benefit older people now and in the future. Older people, their voices and experiences, need to be central to these developments. The Centre for Ageing Research and Development in Ireland The Centre for Ageing Research and Development in Ireland (CARDI) (1) is a not for profit organisation developed by leaders from the ageing field across Ireland (North and South) including age sector focused researchers and academics, statutory and voluntary, and is co-chaired by Professor Robert Stout and Professor Davis Coakley. CARDI has been established to provide a mechanism for greater collaboration among age researchers, for wider dissemination of ageing research information and to advance a research agenda relevant to the needs of older people in Ireland, North and South. Operating at a strategic level and in an advisory capacity, CARDI�۪s work focuses on promoting research co-operation across sectors and disciplines and concentrates on influencing the strategic direction of research into older people and ageing in Ireland. It has been strategically positioned around the following four areas: Identifying and establishing ageing research priorities relevant to policy and practice in Ireland, North and South;Promoting greater collaboration and co-operation on ageing research in order to build an ageing research community in Ireland, North and South;Stimulating research in priority areas that can inform policy and practice relating to ageing and older people in Ireland, North and South;Communicating strategic research issues on ageing to raise the profile of ageing research in Ireland, North and South, and its role in informing policy and practice. Context of Ageing in Ireland Ireland �۪s population is ageing. One million people aged 60 and over now live on the island of Ireland. By 2031, it is expected that Northern Ireland�۪s percentage of older people will increase to 28% and the Republic of Ireland�۪s to 23%. The largest increase will be in the older old; the number aged 80+ is expected to triple by the same date. However while life expectancy has increased, it is not clear that life without disability and ill health has increased to the same extent. A growing number of older people may face the combined effects of a decline in physical and mental function, isolation and poverty. Policymakers, service providers and older people alike recognise the need to create a high quality of life for our ageing population. This challenge can be meet by addressing the problems relating to healthy ageing, reducing inequalities in later life and creating services that are shaped by, and appropriate for, older people. Devolution and Structures of Government in Northern Ireland The Agreement (2) reached in the Multi-Party Negotiations in Belfast 1998 established the Northern Ireland Assembly which has full legislative authority for all transferred matters. The majority of social and economic public policy such as; agriculture, arts, education, health, environment and planning is determined by the Northern Ireland Assembly at Stormont. There are 11 Government Departments covering the main areas of responsibility with 108 elected Members of the Legislative Assembly (MLA�۪s). The powers of the Northern Ireland Assembly do not cover ��� reserved�۪ matters or ��� excepted�۪ matters . These are the responsibility of Westminster and include issues such as, tax, social security, policing, justice, defence, immigration and foreign affairs. Northern Ireland has 18 elected Members of Parliament (MP�۪s) to the House of Commons. Public Policy Context in Northern Ireland The economic, social and political consequence of an ageing population is a challenge for policy makers across government. Considering the complex and diverse causal factors that contribute to ageing in Northern Ireland, there are a number of areas of government policy at regional, national and international levels that are likely to impact in this area. International The Madrid International Plan of Action on Ageing (3) and the Research Agenda on Ageing for the 21st Century (4) provide important mechanisms for furthering research into ageing. The United Kingdom has signed up to these. The Madrid International Plan of Action on Ageing commits member states to a systematic review of the Plan of Action through Regional Implementation Strategies. The United Kingdom�۪s Regional Implementation Strategy covers Northern Ireland. National At National level, pension and social security are high on the agenda. The Pensions Act (5) became law in 2007 and links pensions increases with earnings as opposed to prices from 2012. Additional credits for people raising children and caring for older people to boost their pensions were introduced. Some protections are included for those who lost occupational pensions as a result of underfunded schemes being wound up before April 2005. In relation to State Pensions and benefits, this Act will bring changes to state pensions in future. The Act now places the Pension Credit element which is up-rated in line with or above earnings, on a permanent, statutory footing. Regional At regional level there are a number of age related public policy initiatives that have the potential to impact positively on the lives of older people in Northern Ireland. Some are specific to ageing such as the Ageing in an Inclusive Society (6) and others by their nature are cross-cutting such as Lifetime Opportunities: Governments Anti-Poverty Strategy for Northern Ireland (7). The main public policy framework in Northern Ireland is the Programme for Government: Building a Better Future, 2008-2011(PfG) (8) . The PfG, is the overarching high level policy framework for Northern Ireland and provides useful principles for ageing research and public policy in Northern Ireland. The PfG vision is to build a peaceful, fair and prosperous society in Northern Ireland, with respect for the rule of law. A number of Public Service Agreements (PSA) aligned to the PfG confirm key actions that will be taken to support the priorities that the Government aim to achieve over the next three years. For example objective 2 of PSA 7: Making Peoples�۪ Lives Better: Drive a programme across Government to reduce poverty and address inequality and disadvantage, refers to taking forward strategic action to promote social inclusion for older people; and to deliver a strong independent voice for older people. The Office of the First Minister and deputy First Minister (OFMDFM) have recently appointed an Interim Older People�۪s Advocate, Dame Joan Harbison to provide a focus for older peoples issues across Government. Ageing in an Inclusive Society is the cross-departmental strategy for older people in Northern Ireland and was launched in March 2005. It sets out the approach to be taken across Government to promote and support the inclusion of older people. The vision coupled with six strategic objectives form the basis of the action plans accompanying the strategy. The vision is: ���To ensure that age related policies and practices create an enabling environment, which offers everyone the opportunity to make informed choices so that they may pursue healthy, active and positive ageing.�۝ (Ageing in an Inclusive Society, Office of the First Minister and Deputy First Minister, 2005) Action planning and maintaining momentum across government in relation to this strategy has proved to be slower than anticipated. It is proposed to refresh this Strategy in line with Opportunity Age ��� meeting the challenges of ageing in the 21st Century (9). There are a number of policy levers elsewhere which can also be used to promote the positive aspects of an ageing society. The Investing for Health (10) and A Healthier Future:A 20 Year Vision for Health and Well-being in Northern Ireland (11), seek to ensure that the overall vision for health and wellbeing is achievable and provides a useful framework for ageing policy and research in the health area. These health initiatives have the potential to positively impact on the quality of life of older people and provide a useful framework for improving current policy and practice. In addition to public policy initiatives, the anti-discrimination frameworks in terms of employment in Northern Ireland cover age as well as a range of other grounds. Goods facilitates and services are currently excluded from the Employment Equality (age) Regulations (NI) 2006 (12). Supplementing the anti-discrimination measures, Section 75 of the Northern Ireland Act 1998 (13), unique to Northern Ireland, places a statutory obligation on public authorities in fulfilling their functions to promote equality of opportunity across nine grounds, one of which is age(14). This positive duty has the potential to make a real difference to the lives of older people in Northern Ireland. Those affected by policy decisions must be consulted and their interests taken into account. This provides an opportunity for older people and their representatives to participate in public policy-making, right from the start of the process. Policy and Research Interface ���Ageing research is vital as decisions in relation to policy and practice and resource allocation will be made on the best available information�۝. (CARDI�۪s Strategic Plan 2008-2011) As outlined earlier, CARDI has been established to bridge the gap to ensure that research reaches those involved in making policy decisions. CARDI is stimulating the ageing research agenda in Ireland through a specific research fund that has a policy and practice focus. My work is presently focusing on helping to build a greater awareness of the key policy levers and providing opportunities for those within research and policy to develop closer links. The development of this shared understanding by establishing these links between researchers and policy makers is seen as the best predictor for research utilization. It is important to acknowledge and recognise that researchers and policy makers operate in different institutional, political and cultural contexts. Research however needs to ���resonate�۪ with the contextual factors in which policy makers operate. Conclusions Those working within the public policy field recognise all too often that the development of government policies and initiatives in respect of age does not guarantee that they will result in changes in actual provision of services, despite Government recommendations and commitments. The identification of public policy initiatives as they relate to age has the potential to highlight persistent and entrenched difficulties that social policy has previously failed to address. Furthermore, the identification of these difficulties can maximise the opportunities for progressing these across government. A focus on developing effective and meaningful targets to ensure measurable outcomes in public policy for older people can assist in this. Access to sound, credible and up-to-date evidence will be vital in this respect. As well as a commitment to working across departmental boundaries to effect change. Further details: If you would like to discuss this paper or for further information about CARDI please contact: Judith Cross, Policy Officer, Centre for Ageing Research and Development in Ireland CARDI). t: +44 (0) 28 9069 0066; m: +353 (0) 867 904 171; e: judith@cardi.ie ; or visit our website at: www.cardi.ie References 1) Centre for Ageing Research and Development in Ireland (2008) Strategic Plan 2008-2011. Belfast. CARDI 2) The Agreement: Agreement Reached in the Multi-Party Negotiations. Belfast 1998 3) Madrid International Plan of Action on Ageing. http://www.un.org/ageing/ 4) UN Programme on Ageing (2007) Research Agenda on Ageing for the 21st Century: 2007 Update. New York. New York. UN Programme on Ageing and the International Association of Gerontology and Geriatrics. 5) The Pensions Act 2007 Chapter 22 6) Office of the First Minister and deputy First Minister (2005). Ageing in an Inclusive Society. Belfast. OFMDFM Central Anti-Poverty Unit. 7) Office of the First Minister and deputy First Minister (2005). Lifetime Opportunities: Government�۪s Anti-Poverty and Social Inclusion Strategy for Northern Ireland. Belfast. OFMDFM Central Anti-Poverty Unit. 8) Northern Ireland Executive (2008) Building a Better Future: Programme for Government 2008-2011. Belfast. OFMDFM Economic Policy Unit. 9) Department for Work and Pensions, (2005) Opportunity Age: Meeting the Challenges of Ageing in the 21 st Century. London. DWP. 10) Department of Health, Social Services and Public Safety (DHSS&PS) (2002) Investing for Health. Belfast. DHSS&PS. 11) Department of Health, Social Services and Public Safety (DHSS&PS) (2005) A Healthier Future:A 20 Year Vision for Health and Well-being in Northern Ireland Belfast. DHSS&PS. �� 12) The Employment Equality (Age) Regulations (Northern Ireland) 2006 SR2006 No.261 13) The Northern Ireland Act 1998, Part VII, S75 14) The nine grounds covered under S75 of the Northern Ireland Act are: gender, religion, race, sexual orientation, those with dependents, disability, political opinion, marital status and age.

A mucin like gene different from the previously reported members of the mucin like gene families is transcribed in Trypanosoma cruzi but not in Trypanosoma rangeli

Trypanosoma cruzi expresses mucin like glycoproteins encoded by a complex multigene family. In this work, we report the transcription in T. cruzi but not in T. rangeli of a mucin type gene automatically annotated by the T. cruzi genome project. The gene showed no nucleotide similarities with the previously reported T. cruzi mucin like genes, although the computational analysis of the deduced protein showed that it has the characteristic features of mucins: a signal peptide sequence, O-glycosylation sites, and glycosylphosphatidylinositol (GPI) anchor sequence. The presence in this gene of N- terminal and C- terminal coding sequences common to other annotated mucin like genes suggests the existence of a new mucin like gene family.

Characterization of root apoplastic barriers in Arabidopsis thaliana

In vascular plants, the best-known feature of a differentiated endodermal cell is the "Casparian Strip" (CS). This structure refers to a highly localized cell wall impregnation in the transversal and anticlinal walls of the cell, which surrounds the cell like a belt/ring and is tightly coordinated with respect to neighboring cells. Analogous to tight junctions in animal epithelia, CS in plants act as a diffusion barrier that controls the movement of water and ions from soil into the stele. Since its first description by Robert Caspary in 1865 there have been many attempts to identify the chemical nature of the cell wall deposition in CS. Suberin, lignin, or both have been claimed to be the important components of CS in a series of different species. However, the exact chemical composition of CS has remained enigmatic. This controversy was due to the confusion and lack of knowledge regarding the precise measurement of three developmental stages of the endodermis. The CS represent only the primary stage of endodermal differentiation, which is followed by the deposition of suberin lamellae all around the cellular surface of endodermal cells (secondary developmental stage). Therefore, chemical analysis of whole roots, or even of isolated endodermal tissues, will always find both of the polymers present. It was crucial to clarify this point because this will guide our efforts to understand which cell wall biosynthetic component becomes localized in order to form the CS. The main aim of my work was to find out the major components of (early) CS, as well as their spatial and temporal development, physiological roles and relationship to barrier formation. Employing the knowledge and tools that have been accumulated over the last few years in the model plant Arabidopsis thaliana, various histological and chemical assays were used in this study. A particular feature of my work was to completely degrade, or inhibit formation of lignin and suberin biopolymers by biochemical, classical genetic and molecular approaches and to investigate its effect on CS formation and the establishment of a functional diffusion barrier. Strikingly, interference with monolignol biosynthesis abrogates CS formation and delays the formation of function diffusion barrier. In contrast, transgenic plants devoid of any detectable suberin still develop a functional CS. The combination of all these assays clearly demonstrates that the early CS polymer is made from monolignol (lignin monomers) and is composed of lignin. By contrast, suberin is formed much later as a secondary wall during development of endodermis. These early CS are functionally sufficient to block extracellular diffusion and suberin does not play important role in the establishment of early endodermal diffusion barrier. Moreover, suberin biosynthetic machinery is not present at the time of CS formation. Our study finally concludes the long-standing debate about the chemical nature of CS and opens the door to a new approach in lignin research, specifically for the identification of the components of the CS biosynthetic pathway that mediates the localized deposition of cell walls. I also made some efforts to understand the patterning and differentiation of endodermal passage cells in young roots. In the literature, passage cells are defined as a non- suberized xylem pole associated endodermal cells. Since these cells only contain the CS but not the suberin lamellae, it has been assumed that these cells may offer a continued low-resistance pathway for water and minerals into the stele. Thus far, no genes have been found to be expressed specifically in passage cells. In order to understand the patterning, differentiation, and physiological role of passage it would be crucial to identify some genes that are exclusively expressed in these cells. In order to identify such genes, I first generated fluorescent marker lines of stele-expressed transporters that have been reported to be expressed in the passage cells. My aim was to first highlight the passage cells in a non-specific way. In order to find passage cell specific genes I then adapted a two-component system based on previously published methods for gene expression profiling of individual cell types. This approach will allow us to target only the passage cells and then to study gene expression specifically in this cell type. Taken together, this preparatory work will provide an entry point to understand the formation and role of endodermal passage cells. - Chez les plantes vasculaires, la caractéristique la plus commune des cellules différentiées de l'endoderme est la présence de cadres de Caspary. Cette structure correspond à une imprégnation localisée des parties transversales et anticlinales de la paroi cellulaire. Cela donne naissance, autour de la cellule, à un anneau/cadre qui est coordonné par rapport aux cellules voisines. De manière analogue aux jonctions serrées des épithéliums chez les animaux, les cadres de Caspary agissent chez les plantes comme barrière de diffusion, contrôlant le mouvement de l'eau et des ions à travers la racine entre le sol et la stèle. Depuis leur première description par Robert Caspary en 1865, beaucoup de tentatives ont eu pour but de définir la nature chimique de ces cadres de Caspary. Après l'étude de différentes espèces végétales, à la fois la subérine, la lignine ou les deux ont été revendiquées comme étant des composants importants de ces cadres. Malgré tout, leur nature chimique exacte est restée longtemps énigmatique. Cette controverse provient de la confusion et du manque de connaissance concernant la détermination précise des trois stades de développement de l'endoderme. Les cadres de Caspary représentent uniquement le stade primaire de différentiation de l'endoderme. Celui-ci est suivi par le second stade de différentiation, la déposition de lamelles de subérine tout autour de la cellule endodermal. De ce fait, l'analyse chimique de racines entières ou de cellules d'endoderme isolées ne permet pas de séparer les stades de différentiation primaire et secondaire et aboutit donc à la présence des deux polymères. Il est également crucial de clarifier ce point dans le but de connaître quelle machinerie cellulaire localisée à la paroi cellulaire permet l'élaboration des cadres de Caspary. En utilisant les connaissances et les outils accumulés récemment grâce à la plante modèle Arabidopsis thaliana, divers techniques histologiques et chimiques ont été utilisées dans cette étude. Un point particulier de mon travail a été de dégrader ou d'inhiber complètement la formation de lignine ou de subérine en utilisant des approches de génétique classique ou moléculaire. Le but étant d'observer l'effet de l'absence d'un de ces deux polymères sur la formation des cadres de Caspary et l'établissement d'une barrière de diffusion fonctionnelle. De manière frappante, le fait d'interférer avec la voie de biosynthèse de monolignol (monomères de lignine) abolit la formation des cadres de Caspary et retarde l'élaboration d'une barrière de diffusion fonctionnelle. Par contre, des plantes transgéniques dépourvues d'une quantité détectable de subérine sont quant à elles toujours capables de développer des cadres de Caspary fonctionnels. Mises en commun, ces expériences démontrent que le polymère formant les cadres de Caspary dans la partie jeune de la racine est fait de monolignol, et que de ce fait il s'agit de lignine. La subérine, quant à elle, est formée bien plus tard durant le développement de l'endoderme, de plus il s'agit d'une modification de la paroi secondaire. Ces cadres de Caspary précoces faits de lignine suffisent donc à bloquer la diffusion extracellulaire, contrairement à la subérine. De plus, la machinerie de biosynthèse de la subérine n'est pas encore présente au moment de la formation des cadres de Caspary. Notre étude permet donc de mettre un terme au long débat concernant la nature chimique des cadres de Caspary. De plus, elle ouvre la porte à de nouvelles approches dans la recherche sur la lignine, plus particulièrement pour identifier des composants permettant la déposition localisée de ce polymère dans la paroi cellulaire. J'ai aussi fais des efforts pour mettre en évidence la formation ainsi que le rôle des cellules de passage dans les jeunes racines. Dans la littérature, les cellules de passage sont définies comme de la cellule endodermal faisant face aux pôles xylèmes et dont la paroi n'est pas subérisée. Du fait que ces cellules contiennent uniquement des cadres de Caspary et pas de lamelle de subérine, il a été supposé qu'elles ne devraient offrir que peu de résistance au passage de l'eau et des nutriments entre le sol et la stèle. Le rôle de ces cellules de passage est toujours loin d'être clair, de plus aucun gène s'exprimant spécifiquement dans ces cellules n'a été découvert à ce jour. De manière à identifier de tels gènes, j'ai tout d'abord généré des marqueurs fluorescents pour des transporteurs exprimés dans la stèle mais dont l'expression avait également été signalée dans l'endoderme, uniquement dans les cellules de passage. J'ai ensuite développé un système à deux composants basé sur des méthodes déjà publiées, visant principalement à étudier le profil d'expression génique dans un type cellulaire donné. En recoupant les gènes exprimés spécifiquement dans l'endoderme à ceux exprimés dans la stèle et les cellules de passage, il nous sera possible d'identifier le transriptome spécifique de ces cellules. Pris dans leur ensemble, ces résultats devraient donner un bon point d'entrée dans la définition et la compréhension des cellules de passage.

Neutrophil transepithelial migration: role of toll-like receptors in mucosal inflammation

The symptomatic phases of many inflammatory diseases are characterized by migration of large numbers of neutrophils (PMN) across a polarized epithelium and accumulation within a lumen. For example, acute PMN influx is common in diseases of the gastrointestinal system (ulcerative colitis, Crohn's disease, bacterial enterocolitis, gastritis), hepatobiliary system (cholangitis, acute cholecystitis), respiratory tract (bronchial pneumonia, bronchitis, cystic fibrosis, bronchiectasis), and urinary tract (pyelonephritis, cystitis). Despite these observations, the molecular basis of leukocyte interactions with epithelial cells is incompletely understood. In vitro models of PMN transepithelial migration typically use N-formylated bacterial peptides such as fMLP in isolation to drive human PMNs across epithelial monolayers. However, other microbial products such as lipopolysaccharide (LPS) are major constituents of the intestinal lumen and have potent effects on the immune system. In the absence of LPS, we have shown that transepithelial migration requires sequential adhesive interactions between the PMN beta2 integrin CD11b/CD18 and JAM protein family members. Other epithelial ligands appear to be abundantly represented as fucosylated proteoglycans. Further studies indicate that the rate of PMN migration across mucosal surfaces can be regulated by the ubiquitously expressed transmembrane protein CD47 and microbial-derived factors, although many of the details remain unclear. Current data suggests that Toll-like receptors (TLR), which recognize specific pathogen-associated molecular patterns (PAMPs), are differentially expressed on both leukocytes and mucosal epithelial cells while serving to modulate leukocyte-epithelial interactions. Exposure of epithelial TLRs to microbial ligands has been shown to result in transcriptional upregulation of inflammatory mediators whereas ligation of leukocyte TLRs modulate specific antimicrobial responses. A better understanding of these events will hopefully provide new insights into the mechanisms of epithelial responses to microorganisms and ideas for therapies aimed at inhibiting the deleterious consequences of mucosal inflammation.

Do brief alcohol motivational interventions work like we think they do?

BACKGROUND: Questions remain about how brief motivational interventions (BMIs) for unhealthy alcohol use work, and addressing these questions may be important for improving their efficacy. Therefore, we assessed the effects of various characteristics of BMIs on drinking outcomes across 3 randomized controlled trials (RCTs). METHODS: Audio recordings of 314 BMIs were coded. We used the global rating scales of the Motivational Interviewing Skills Code (MISC) 2.1: counselor's acceptance, empathy, and motivational interviewing (MI) spirit, and patient's self-exploration were rated. MI proficiency was defined as counselor's rating scale scores ≥5. We also used the structure, confrontation, and advice subscale scores of the Therapy Process Rating Scale and the Working Alliance Inventory. We examined these process characteristics in interventions across 1 U.S. RCT of middle-aged medical inpatients with unhealthy alcohol use (n = 124) and 2 Swiss RCTs of young men with binge drinking in a nonclinical setting: Swiss-one (n = 62) and Swiss-two (n = 128). We assessed the associations between these characteristics and drinks/d reported by participants 3 to 6 months after study entry. RESULTS: In all 3 RCTs, mean MISC counselor's rating scales scores were consistent with MI proficiency. In overdispersed Poisson regression models, most BMI characteristics were not significantly associated with drinks/d in follow-up. In the U.S. RCT, confrontation and self-exploration were associated with more drinking. Giving advice was significantly associated with less drinking in the Swiss-one RCT. Contrary to expectations, MI spirit was not consistently associated with drinking across studies. CONCLUSIONS: Across different populations and settings, intervention characteristics viewed as central to efficacious BMIs were neither robust nor consistent predictors of drinking outcome. Although there may be alternative reasons why the level of MI processes was not predictive of outcomes in these studies (limited variability in scores), efforts to understand what makes BMIs efficacious may require attention to factors beyond intervention process characteristics typically examined.

Thogoto virus infection induces sustained type I interferon responses that depend on RIG-I-like helicase signaling of conventional dendritic cells.

Type I interferon (IFN-α/β) induction upon viral infection contributes to the early antiviral host defense and ensures survival until the onset of adaptive immunity. Many viral infections lead to an acute, transient IFN expression which peaks a few hours after infection and reverts to initial levels after 24 to 36 h. Robust IFN expression often is conferred by specialized plasmacytoid dendritic cells (pDC) and may depend on positive-feedback amplification via the type I IFN receptor (IFNAR). Here, we show that mice infected with Thogoto virus (THOV), which is an influenza virus-like orthomyxovirus transmitted by ticks, mounted sustained IFN responses that persisted up to 72 h after infection. For this purpose, we used a variant of THOV lacking its IFN-antagonistic protein ML, an elongated version of the matrix (M) protein [THOV(ΔML)]. Of note, large amounts of type I IFN were also found in the serum of mice lacking the IFNAR. Early IFN-α expression seemed to depend on Toll-like receptor (TLR) signaling, whereas prolonged IFN-α responses strictly depended on RIG-I-like helicase (RLH) signaling. Unexpectedly, THOV(ΔML)-infected bone marrow-derived pDC (BM-pDC) produced only moderate IFN levels, whereas myeloid DC (BM-mDC) showed massive IFN induction that was IPS-1-dependent, suggesting that BM-mDC are involved in the massive, sustained IFN production in THOV(ΔML)-infected animals. Thus, our data are compatible with the model that THOV(ΔML) infection is sensed in the acute phase via TLR and RLH systems, whereas at later time points only RLH signaling is responsible for the induction of sustained IFN responses.

TRADD protein is an essential component of the RIG-like helicase antiviral pathway

Upon detection of viral RNA, the helicases RIG-I and/or MDA5 trigger, via their adaptor Cardif (also known as IPS-1, MAVS, or VISA), the activation of the transcription factors NF-kappaB and IRF3, which collaborate to induce an antiviral type I interferon (IFN) response. FADD and RIP1, known as mediators of death-receptor signaling, are implicated in this antiviral pathway; however, the link between death-receptor and antiviral signaling is not known. Here we showed that TRADD, a crucial adaptor of tumor necrosis factor receptor (TNFRI), was important in RIG-like helicase (RLH)-mediated signal transduction. TRADD is recruited to Cardif and orchestrated complex formation with the E3 ubiquitin ligase TRAF3 and TANK and with FADD and RIP1, leading to the activation of IRF3 and NF-kappaB. Loss of TRADD prevented Cardif-dependent activation of IFN-beta, reduced the production of IFN-beta in response to RNA viruses, and enhanced vesicular stomatitis virus replication. Thus, TRADD is not only an essential component of proinflammatory TNFRI signaling, but is also required for RLH-Cardif-dependent antiviral immune responses