HPK1 Associates with SKAP-HOM to Negatively Regulate Rap1-Mediated B-Lymphocyte Adhesion

BACKGROUND: Hematopoietic progenitor kinase 1 (HPK1) is a Ste20-related serine/threonine kinase activated by a range of environmental stimuli including genotoxic stress, growth factors, inflammatory cytokines and antigen receptor triggering. Being inducibly recruited to membrane-proximal signalling scaffolds to regulate NFAT, AP-1 and NFkappaB-mediated gene transcription in T-cells, the function of HPK1 in B-cells to date remains rather ill-defined. METHODOLOGY/PRINCIPAL FINDINGS: By using two loss of function models, we show that HPK1 displays a novel function in regulating B-cell integrin activity. Wehi 231 lymphoma cells lacking HPK1 after shRNA mediated knockdown exhibit increased basic activation levels of Ras-related protein 1 (Rap1), accompanied by a severe lymphocyte function-associated antigen-1 (LFA-1) dependent homotypic aggregation and increased adhesion to intercellular adhesion molecule 1 (ICAM-1). The observed phenotype of enhanced integrin activity is caused downstream of Src, by a signalling module independent of PI3K and PLC, involving HPK1, SKAP55 homologue (SKAP-HOM) and Rap1-GTP-interacting adaptor molecule (RIAM). This alters actin dynamics and renders focal adhesion kinase (FAK) constitutively phosphorylated. Bone marrow and splenic B-cell development of HPK1(-/-) mice are largely unaffected, except age-related tendencies for increased splenic cellularity and BCR downregulation. In addition, naïve splenic knockout B-cells appear hyperresponsive to a range of stimuli applied ex vivo as recently demonstrated by others for T-cells. CONCLUSIONS/SIGNIFICANCE: We therefore conclude that HPK1 exhibits a dual function in B-cells by negatively regulating integrin activity and controlling cellular activation, which makes it an interesting candidate to study in pathological settings like autoimmunity and cancer

Activated iNKT Cells Promote Memory CD8+ T Cell Differentiation during Viral Infection

α-galactosylceramide (α-GalCer) is the prototypical lipid ligand for invariant NKT cells. Recent studies have proposed that α-GalCer is an effective adjuvant in vaccination against a range of immune challenges, however its mechanism of action has not been completely elucidated. A variety of delivery methods have been examined including pulsing dendritic cells with α-GalCer to optimize the potential of α-GalCer. These methods are currently being used in a variety of clinical trials in patients with advanced cancer but cannot be used in the context of vaccine development against pathogens due to their complexity. Using a simple delivery method, we evaluated α-GalCer adjuvant properties, using the mouse model for cytomegalovirus (MCMV). We measured several key parameters of the immune response to MCMV, including inflammation, effector, and central memory CD8+ T cell responses. We found that α-GalCer injection at the time of the infection decreases viral titers, alters the kinetics of the inflammatory response, and promotes both increased frequencies and numbers of virus-specific memory CD8+ T cells. Overall, our data suggest that iNKT cell activation by α-GalCer promotes the development of long-term protective immunity through increased fitness of central memory CD8+ T cells, as a consequence of reduced inflammation

Sterowanie nawodnieniami za pomocą technologii czujników wilgotności gleby

Water is a sensitive and limited resource, mainly in intensively used agricultural areas in Austria , where groundwater is used as drinking water as well as for irrigation purposes. In order to guarantee a sustainable use of irrigation water, soil water measurement devices can be used to optimise irrigation, which means that controlling the soil water content in the entire root system may prevent water stress due to water deficiency on the one hand, and over wetting on the other hand. Furthermore, losses of nutrients due to leaching can be avoided. Several research studies on that topic were initiated during the last few years. The soil water status on selected fields planted with different crops (onions, carrots, sugar beets, sweet maize, zucchini) was monitored continuously by FDR (Frequency Domain Reflectometry) soil water measurement devices. Sensors in different depths measure the plant water uptake in the root zone under standard irrigation practices on different sites and different soils, respectively. The deepest sensor is installed to avoid deep percolation caused by over irrigation. By means of these data, irrigation could be regulated based on the actual plant water requirements to keep the soil water content within an ideal range for crop development.W pracy omówiono tematykę ciągłego pomiaru uwilgotnienia gleby z wykorzystaniem najnowszej technologii informatycznej. Podano zarówno podstawy teoretyczne, jak też zagadnienia praktyczne. Opisana technologia polega na zastosowaniu reflektometrów w domenie częstotliwości FDR - wilgotnościomierzy wykorzystujących pomiar pojemności elektrycznej. Urządzenie to umożliwia sterowanie nawodnieniami oraz ciągłe monitorowanie ilości wody magazynowanej w danym czasie w profilu glebowym na określonej głębokości (zasięg 0-80 cm). Przedstawiono wieloletnie wyniki doświadczeń polowych w Austrii, uzyskane na obiektach, na których stosowano metodę sterowania nawodnieniami upraw polowych oraz warzyw w latach 2001-2006. Omówiono dwa różne systemy monitorowania wilgotności gleby w celu sterowania nawodnieniami: Sentek EnviroScan: dane mogą być ładowane w trybie odbioru (do własnego komputera) lub przez modem GSM - ten system wykorzystano w uprawie cebuli, cukinii, kukurydzy pastewnej, marchwi oraz buraków cukrowych; Przekaźnik typu Adcon - zastosowany w uprawie ziemniaków, buraków cukrowych, cebuli, marchwi drobnej oraz fasoli, z czujnikami EasyAG-Sentek umieszczonymi na głębokości 10, 20, 30 i 50 cm. Badania udowodniły, że można zmniejszyć straty wody w nawodnieniach rolniczych dzięki ciągłemu monitorowaniu uwilgotnienia gleby na kilku głębokościach

WATER AND LANDSCAPE MANAGEMENT ASPECTS IN THE NEUSIEDLER SEE REGION

Abstract The "Neusiedler See-Seewinkel" is the first and biggest Ramsar Site in Austria designated in 1982. In 2009 a transboundary Austrian-Hungarian site "Neusiedler See-Seewinkel-Hanság" was inscribed to the List of Wetlands of International Importance including present Ramsar Sites in both countries. Aside from that, a national park "Neusiedler See-Seewinkel" was founded in 1993 and co-managed with the Hungarian national park "Fertő-Hanság", founded in 1991. These sites consist of the lake Neusiedler See itself, small saline lakes, salt meadows and fens. The Neusiedler See is a steppe lake with an extensive reed area and marshes. It is one of the biggest wetlands in Central Europe covering a total area of 321 km², whereof the free water surface covers 143 km² and the reed belt covers 178 km² (Csaplovics, 1997). The water balance of the lake is dominated by precipitation and evaporation and just minor inflow of the river Wulka. Originally, the lake has no natural outflow, but at the end of the 19th century an artificial channel for access water drainage was constructed. Nowadays, the lake water level is regulated by a weir according to operation rules and supervised by an Austro-Hungarian committee for water bodies. The operation rules define a water level range; however the lower limit is prone to draught conditions. For this reason, an important aspect of water management actions, like building of small weirs or closing of channels, is the water retention in the area. For improvement of lake water management a cooperation project "New Geodetic Survey of the Lake Neusiedl-Hanság-Channel System" between Hungary and Austria was initialised in order to provide a homogeneous topographic data base of the Neusiedler See basin and the Hanság-Channel including the investigation of the huge, stratified mud body of the lake and the reed bed. For the detection of the sludge layer and the lake bed echo sounding techniques of spatial and vertical high resolution were used for the free water surface. Single-point measurements were conducted as a reference with a new adapted measuring technique. They provide a high-resolution vertical profile of the sludge distribution and the bottom layer. Further single-point measurements were conducted in shallow water areas below 60 cm, where the use of echo sounding is limited, as well as in the hardly accessible reed belt. The acquired knowledge about the state of the lake is essential for an appropriate lake and wetland management and overall landscape preservation

Mechanisms for segregating T cell receptor and adhesion molecules during immunological synapse formation in Jurkat T cells

T cells interacting with antigen-presenting cells (APCs) form an “immunological synapse” (IS), a bull's-eye pattern composed of a central supramolecular activation cluster enriched with T cell receptors (TCRs) surrounded by a ring of adhesion molecules (a peripheral supramolecular activation cluster). The mechanism responsible for segregating TCR and adhesion molecules remains poorly understood. Here, we show that immortalized Jurkat T cells interacting with a planar lipid bilayer (mimicking an APC) will form an IS, thereby providing an accessible model system for studying the cell biological processes underlying IS formation. We found that an actin-dependent process caused TCR and adhesion proteins to cluster at the cell periphery, but these molecules appeared to segregate from one another at the earliest stages of microdomain formation. The TCR and adhesion microdomains attached to actin and were carried centripetally by retrograde flow. However, only the TCR microdomains penetrated into the actin-depleted cell center, whereas the adhesion microdomains appeared to be unstable without an underlying actin cytoskeleton. Our results reveal that TCR and adhesion molecules spatially partition from one another well before the formation of a mature IS and that differential actin interactions help to shape and maintain the final bull's-eye pattern of the IS