NK cell cytotoxicity towards pluripotent stem cells and their neural progeny: impacts of activating and inhibitory receptors and KIR/HLA mismatch.

Pluripotent stem cells provide opportunities for treating injuries and previously incurable diseases. A major concern is the immunogenicity of stem cells and their progeny. Here, we have dissected the molecular mechanisms that allow natural killer (NK) cells to respond to human pluripotent stem cells, investigating a wide selection of activating and inhibitory NK cell receptors and their ligands.

Phosphorus uptake and toxicity are delimited by mycorrhizal symbiosis in P-sensitive but not in P-tolerant .

Many plant species from regions with ancient, highly weathered nutrient-depleted soils have specialized adaptations for acquiring phosphorus (P) and are sensitive to excess P supply. Mycorrhizal associations may regulate P uptake at high external P concentrations, potentially reducing P toxicity. We predicted that excess P application will negatively impact species from the nutrient-depleted Jarrah forest of Western Australia and that mycorrhizal inoculation will reduce P toxicity by regulating P uptake.

Climate drives patterns of seed traits in Quercus species across China.

Traits enabling seeds to survive post-dispersal desiccation and subsequently germinate are important aspects of plant regeneration for species with desiccation-sensitive seeds. However, how desiccation and germination-related traits co-vary and relate to patterns of climate variation are unknown. We investigated physiological traits related to desiccation and germination of desiccation-sensitive seeds from 19 Quercus species, which typically dominate subalpine, subtropical and temperate forests in China.

Human macrophage C-type lectin forms a heteromeric receptor complex with Mincle but not Dectin-2.

MCL, Mincle and Dectin-2 are C-type lectin receptors expressed by subsets of myeloid cells, and their genes cluster together in the APLEC/Dectin-2 gene complex. We have previously shown that MCL and Mincle form a heterodimer in the rat, and others have shown that MCL and Dectin-2 form a heterodimer in the mouse. In the rat, Dectin-2 is a pseudogene, but here, we examine the association of the three receptors in human.

C-type lectin receptors Mcl and Mincle control development of multiple sclerosis-like neuroinflammation.

Pattern recognition receptors (PRRs) are crucial for responses to infections and tissue damage; however, their role in autoimmunity is less clear. Herein we demonstrate that 2 C-type lectin receptors (CLRs) Mcl and Mincle play an important role in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Congenic rats expressing lower levels of Mcl and Mincle on myeloid cells exhibited a drastic reduction in EAE incidence.

Dendritic Cell Activating Receptor 1 (DCAR1) Associates With FcεRIγ and Is Expressed by Myeloid Cell Subsets in the Rat.

Dendritic cell activating receptor-1 (DCAR1) is a cell-surface receptor encoded by the Antigen Presenting Lectin-like gene Complex (APLEC). We generated a mouse monoclonal antibody against rat DCAR1, and used this to characterize receptor expression and function. Rat DCAR1 was expressed on minor subsets of myeloid cells in lymphoid tissue, but was uniformly expressed at a high level by eosinophils, and at a low level by neutrophils.

B7H6 is a functional ligand for NKp30 in rat and cattle and determines NKp30 reactivity toward human cancer cell lines.

NK cells kill cancer cells and infected cells upon activation by cell surface receptors. Human NKp30 is an activating receptor expressed by all mature NK cells. The B7 family member B7H6 has been identified as one ligand for NKp30.

An improved CPRG colorimetric ligand-receptor signal transduction assay based on beta-galactosidase activity in mammalian BWZ-reporter cells.

Introduction: Reporter cells expressing a chimeric receptor that activates a reporter can be used for screening ligand-mediated signal transduction. In this study, we used reporter cells harboring an NFAT/lacZ construct that express β-galactosidase when the chimeric receptor is stimulated. A colorimetric β-galactosidase substrate, chlorophenol-red β-d-galactopyranoside (CPRG), was used to detect enzymatic activity.

Thermal buffering capacity of the germination phenotype across the environmental envelope of the Cactaceae.

Recruitment from seeds is among the most vulnerable stage for plants as global temperatures change. While germination is the means by which the vast majority of the world's flora regenerate naturally, a framework for accurately predicting which species are at greatest risk of germination failure during environmental perturbation is lacking. Taking a physiological approach, we assess how one family, the Cactaceae, may respond to global temperature change based on the thermal buffering capacity of the germination phenotype.

The Alzheimer's disease risk factors apolipoprotein E and TREM2 are linked in a receptor signaling pathway.

Background: Triggering receptor expressed on myeloid cells 2 (TREM2) and apolipoprotein E (APOE) are genetically linked to Alzheimer's disease. Here, we investigated whether human ApoE mediates signal transduction through human and murine TREM2 and sought to identify a TREM2-binding domain in human ApoE.

Methods: To investigate cell signaling through TREM2, a cell line was used which expressed an NFAT-inducible β-galactosidase reporter and human or murine TREM2, fused to CD8 transmembrane and CD3ζ intracellular signaling domains.

The Activating Human NK Cell Receptor KIR2DS2 Recognizes a β-Microglobulin-Independent Ligand on Cancer Cells.

The functions of activating members of the killer cell Ig-like receptor (KIR) family are not fully understood, as the ligands for these receptors are largely unidentified. In this study, we report that KIR2DS2 reporter cells recognize a ligand expressed by cancer cell lines. All cancer targets recognized by KIR2DS2 were also recognized by KIR2DL2 and KIR2DL3 reporters.

Alternating temperature combined with darkness resets base temperature for germination (T ) in photoblastic seeds of Lippia and Aloysia (Verbenaceae).

Thermal time models for seed germination assume a continuum of rate responses in the sub-optimal temperature range. Generally, the models describe germination performance in non-dormant seeds at constant temperatures, yet alternating temperature (AT) is a feature of many natural environments. We studied the possible interacting effects of AT on germination progress in photoblastic seeds of three aromatic-medicinal Verbenaceae species in the genera Lippia and Aloysia.

Management-driven evolution in a domesticated ecosystem.

Millennia of human land-use have resulted in the widespread occurrence of what have been coined 'domesticated ecosystems'. The anthropogenic imprints on diversity, composition, structure and functioning of such systems are well documented. However, evolutionary consequences of human activities in these ecosystems are enigmatic.

Campanulaceae: a family with small seeds that require light for germination.

Background And Aims: The Campanulaceae is a large cosmopolitan family, but is understudied in terms of germination, and seed biology in general. Small seed mass (usually in the range 10-200 µg) is a noteworthy trait of the family, and having small seeds is commonly associated with a light requirement. Thus, the purpose of this study was to investigate the effect of light on germination in 131 taxa of the Campanulaceae family, from all five continents of its distribution.

Mincle, the receptor for mycobacterial cord factor, forms a functional receptor complex with MCL and FcεRI-γ.

Upon receptor activation, the myeloid C-type lectin receptor Mincle signals via the Syk-CARD9-Bcl10-MALT1 pathway. It does so by recruiting the ITAM-bearing FcεRI-γ. The related receptor macrophage C-type Lectin (MCL) has also been shown to be associated with Syk and to be dependent upon this signaling axis.

Conditional cold avoidance drives between-population variation in germination behaviour in Calluna vulgaris.

Background And Aims: Across their range, widely distributed species are exposed to a variety of climatic and other environmental conditions, and accordingly may display variation in life history strategies. For seed germination in cold climates, two contrasting responses to variation in winter temperature have been documented: first, an increased ability to germinate at low temperatures (cold tolerance) as winter temperatures decrease, and secondly a reduced ability to germinate at low temperatures (cold avoidance) that concentrates germination towards the warmer parts of the season.

Methods: Germination responses were tested for Calluna vulgaris, the dominant species of European heathlands, from ten populations collected along broad-scale bioclimatic gradients (latitude, altitude) in Norway, covering a substantial fraction of the species' climatic range.

Rat macrophage C-type lectin is an activating receptor expressed by phagocytic cells.

Macrophage C-type lectin (MCL) is a membrane surface receptor encoded by the Antigen Presenting Lectin-like gene Complex (APLEC). We generated a mouse monoclonal antibody for the study of this receptor in the rat. We demonstrate that rat MCL is expressed on blood monocytes and neutrophils, as well as on several tissue macrophage populations, including alveolar and peritoneal cavity macrophages.

Physical dormancy in seeds: a game of hide and seek?

Historically, 'physical dormancy', or 'hard seededness', where seeds are prevented from germinating by a water-impermeable seed coat, is viewed as a dormancy mechanism. However, upon water uptake, resumption of metabolism leads to the unavoidable release of volatile by-products, olfactory cues that are perceived by seed predators. Here, we examine the hypothesis that hard seeds are an anti-predator trait that evolved in response to powerful selection by small mammal seed predators.

Identification of an MHC class I ligand for the single member of a killer cell lectin-like receptor family, KLRH1.

Natural killer cells are able to recognize and kill target cells according to differences in MHC class I expression. In rodents, the Ly49 receptors are primarily responsible for this MHC differentiation. We previously described the cloning of a novel C-type lectin-like receptor, KLRH1, encoded in the NK complex adjacent to the Ly49 genes and expressed by subsets of NK and NKT cells.

Rates of water loss and uptake in recalcitrant fruits of Quercus species are determined by pericarp anatomy.

Desiccation-sensitive recalcitrant seeds and fruits are killed by the loss of even moderate quantities of water. Consequently, minimizing the rate of water loss may be an important ecological factor and evolutionary driver by reducing the risk of mortality during post-dispersal dry-spells. For recalcitrant fruits of a range of Quercus species, prolonged drying times have been observed previously.

Paired opposing leukocyte receptors recognizing rapidly evolving ligands are subject to homogenization of their ligand binding domains.

Some leukocyte receptors come in groups of two or more where the partners share ligand(s) but transmit opposite signals. Some of the ligands, such as MHC class I, are fast evolving, raising the problem of how paired opposing receptors manage to change in step with respect to ligand binding properties and at the same time conserve opposite signaling functions. An example is the KLRC (NKG2) family, where opposing variants have been conserved in both rodents and primates.

The role of botanic gardens in the science and practice of ecological restoration.

Many of the skills and resources associated with botanic gardens and arboreta, including plant taxonomy, horticulture, and seed bank management, are fundamental to ecological restoration efforts, yet few of the world's botanic gardens are involved in the science or practice of restoration. Thus, we examined the potential role of botanic gardens in these emerging fields. We believe a reorientation of certain existing institutional strengths, such as plant-based research and knowledge transfer, would enable many more botanic gardens worldwide to provide effective science-based support to restoration efforts.

The rat NK cell receptors Ly49s4 and Ly49i4 recognize nonclassical MHC-I molecules on Listeria monocytogenes-infected macrophages.

Ly49 receptors in rodents, like KIRs in humans, regulate NK cell activity. Although inhibitory Ly49 receptors clearly recognize MHC-I molecules, ligands for the activating Ly49 receptors are less well defined. Here, we show that the activating Ly49s4 and the inhibitory Ly49i4 receptors recognize nonclassical MHC-I molecules on the rat macrophage cell line R2 (RT1(d)).

The complete inventory of receptors encoded by the rat natural killer cell gene complex.

The natural killer cell gene complex (NKC) encodes receptors belonging to the C-type lectin superfamily expressed primarily by NK cells and other leukocytes. In the rat, the chromosomal region that starts with the Nkrp1a locus and ends with the Ly49i8 locus is predicted to contain 67 group V C-type lectin superfamily genes, making it one of the largest congregation of paralogous genes in vertebrates. Based on physical proximity and phylogenetic relationships between these genes, the rat NKC can be divided into four major parts.