Differential bone marrow homing capacity of VLA-4 and CD38 high expressing chronic lymphocytic leukemia cells

Background

VLA-4 and CD38 predict a poor clinical outcome in chronic lymphocytic leukemia (CLL). We used CLL samples with discordant VLA-4/CD38 risk to address their individual roles in human bone marrow infiltration (BM), CLL cell homing to murine BM, and in supportive CLL cell-stromal cell interactions.

Methods

VLA-4, CD38, and Ki-67 expression was measured in CLL cells from peripheral blood (PB) and bone marrow (BM) aspirates. CLL BM infiltration rates, routinely determined by Pathology, were correlated to VLA-4 and CD38 expression. Short-term homing capacity of CLL cells was evaluated by adoptive transfer experiments. CLL cell viability and adhesion in stromal cell co-culture was determined.

Results

About 20% of CLL samples in our cohort displayed discordant VLA-4 and CD38 risk, with either high VLA-4 and low CD38 risk or vice versa. Using particularly such samples, we observed that VLA-4, and not CD38, was responsible for recirculation of CLL cells to murine BM. Human BM infiltration was also significantly higher in patients with high VLA-4 risk but not high CD38 risk. However, both molecules acted as independent prognostic markers. While both VLA-4 and CD38 expression were increased in BM-derived CLL cells, and VLA-4+ and CD38+ subpopulations showed enriched Ki-67 expression, VLA-4 did not contribute to CLL cell protection by stromal cells in vitro.

Conclusions

Our data argue for a prominent role of VLA-4 but not CD38 expression in the homing of CLL cells to BM niches and in human BM infiltration,but only a limited role in their protection by stromal cells.     

Aphids indirectly increase virulence and transmission potential of a monarch butterfly parasite by reducing defensive chemistry of a shared food plant

Parasites and hosts live in communities consisting of many interacting species, but few studies have examined how communities affect parasite virulence and transmission. We studied a food web consisting of two species of milkweed, two milkweed herbivores (monarch butterfly and oleander aphid) and a monarch butterfly-specific parasite. We found that the presence of aphids increased the virulence and transmission potential of the monarch butterfly's parasite on one milkweed species. These increases were associated with aphid-induced decreases in the defensive chemicals of milkweed plants. Our experiment suggests that aphids can indirectly increase the virulence and transmission potential of monarch butterfly parasites, probably by altering the chemical composition of a shared food plant. These results indicate that species that are far removed from host-parasite interactions can alter such interactions through cascading indirect effects in the food web. As such, indirect effects within ecological communities may drive the dynamics and evolution of parasites.     

Wide geographical and ecological distribution of nitrogen and carbon gains from fungi in pyroloids and monotropoids (Ericaceae) and in orchids

* Stable isotope abundance analyses recently revealed that some European green orchids and pyroloids (Ericaceae) are partially myco-heterotrophic, exploiting mycorrhizal fungi for organic carbon and nitrogen. Here we investigate related species to assess their nutritional mode across various forest and climate types in Germany and California. * C- and N-isotope signatures of five green pyroloids, three green orchids and several obligate myco-heterotrophic species (including the putatively fully myco-heterotrophic Pyrola aphylla) were analysed to quantify the green plants' nutrient gain from their fungal partners and to investigate the constancy of enrichment in (13)C and (15)N of fully myco-heterotrophic plants from diverse taxa and locations relative to neighbouring autotrophic plants. * All green pyroloid and one orchid species showed significant (15)N enrichment, confirming incorporation of fungi-derived N compounds while heterotrophic C gain was detected only under low irradiance in Orthilia secunda. Pyrola aphylla had an isotope signature equivalent to those of fully myco-heterotrophic plants. * It is demonstrated that primarily N gain from mycorrhizal fungi occurred in all taxonomic groups investigated across a wide range of geographical and ecological contexts. The (13)C and (15)N enrichment of obligate myco-heterotrophic plants relative to accompanying autotrophic plants turned out as a fairly constant parameter.     

Live Faecalibacterium prausnitzii in an apical anaerobic model of the intestinal epithelial barrier

Faecalibacterium prausnitzii, an abundant member of the human commensal microbiota, has been proposed to have a protective role in the intestine. However, it is an obligate anaerobe, difficult to co‐culture in viable form with oxygen‐requiring intestinal cells. To overcome this limitation, a unique apical anaerobic model of the intestinal barrier, which enabled co‐culture of live obligate anaerobes with the human intestinal cell line Caco‐2, was developed. Caco‐2 cells remained viable and maintained an intact barrier for at least 12 h, consistent with gene expression data, which suggested Caco‐2 cells had adapted to survive in an oxygen‐reduced atmosphere. Live F. prausnitzii cells, but not ultraviolet (UV)‐killed F. prausnitzii, increased the permeability of mannitol across the epithelial barrier. Gene expression analysis showed inflammatory mediators to be expressed at lower amounts in Caco‐2 cells exposed to live F. prausnitzii than UV‐killed F. prausnitzii, This, consistent with previous reports, implies that live F. prausnitzii produces an anti‐inflammatory compound in the culture supernatant, demonstrating the value of a physiologically relevant co‐culture system that allows obligate anaerobic bacteria to remain viable.     

Aeroallergens and pollinosis: Molecular and immunological characteristics of cloned pollen allergens

Affecting almost twenty percent of thepopulation in industrialized countries,allergic diseases such as asthma and seasonalrhinitis result from the development ofimmediate hypersensitivity to otherwiseinnocuous components of the environment. Pollen, the male gametophyte of flowering plantspecies, is one of the most predominant sourcesof environmental allergens, and a significantcause of allergic diseases. This reviewdiscusses the nature of pollen proteins asallergens, their effect on the human immunesystem and their mode of environmentaltransmission, including effects of theinteraction between pollen aeroallergens andair pollution. The influence of cross-reactivepollen allergens to the incidence of foodsensitivities is also discussed. Floweringplant species that possess allergenic pollen,identified with allergens cloned from thesespecies, are also discussed.     

Synthesis and SAR of analogs of the M1 allosteric agonist TBPB. Part II: Amides, sulfonamides and ureas--the effect of capping the distal basic piperidine nitrogen

This letter describes the further synthesis and SAR, developed through an iterative analog library approach, of analogs of the highly selective M1 allosteric agonist TBPB by deletion of the distal basic piperidine nitrogen by the formation of amides, sulfonamides and ureas. Despite the large change in basicity and topology, M1 selectivity was maintained.     

Enhanced efficiency through nuclear localization signal fusion on phage PhiC31-integrase: activity comparison with Cre and FLPe recombinase in mammalian cells

The integrase of the phage ΦC31 recombines an attP site in the phage genome with a chromosomal attB site of its Streptomyces host. We have utilized the integrase-mediated reaction to achieve episomal and genomic deletion of a reporter gene in mammalian cells, and provide the first comparison of its efficiency with other recombinases in a new assay system. This assay demonstrated that the efficiency of ΦC31-integrase is significantly enhanced by the C-terminal, but not the N-terminal, addition of a nuclear localization signal and becomes comparable with that of the widely used Cre/loxP system. Furthermore, we found that the improved FLP recombinase, FLPe, exhibits only 10% recombination activity on chromosomal targets as compared with Cre, whereas the Anabaena derived XisA recombinase is essentially inactive in mammalian cells. These results provide the first demonstration that a nuclear localisation signal and its position within a recombinase can be important for its efficiency in mammalian cells and establish the improved ΦC31-integrase as a new tool for genome engineering.     

Synthesis and activity of a novel class of tribasic macrocyclic antibiotics: the triamilides

The stereoselective synthesis of two novel series of tribasic macrocyclic antibiotics with potent in vitro activity against Pasteurella multocida and Escherichia coli strains of bacteria is described. The in vitro activity can be significantly influenced by the nature of the substituents on the C-4" aminoalcohol, with the stereochemistry of the C-4" alcohol playing a less critical role. The effect of substitution and stereochemistry on the in vivo activity in a murine model of respiratory infection is also described.     

Linking Changes in Epithelial Morphogenesis to Cancer Mutations Using Computational Modeling

Most tumors arise from epithelial tissues, such as mammary glands and lobules, and their initiation is associated with the disruption of a finely defined epithelial architecture. Progression from intraductal to invasive tumors is related to genetic mutations that occur at a subcellular level but manifest themselves as functional and morphological changes at the cellular and tissue scales, respectively. Elevated proliferation and loss of epithelial polarization are the two most noticeable changes in cell phenotypes during this process. As a result, many three-dimensional cultures of tumorigenic clones show highly aberrant morphologies when compared to regular epithelial monolayers enclosing the hollow lumen (acini). In order to shed light on phenotypic changes associated with tumor cells, we applied the bio-mechanical IBCell model of normal epithelial morphogenesis quantitatively matched to data acquired from the non-tumorigenic human mammary cell line, MCF10A. We then used a high-throughput simulation study to reveal how modifications in model parameters influence changes in the simulated architecture. Three parameters have been considered in our study, which define cell sensitivity to proliferative, apoptotic and cell-ECM adhesive cues. By mapping experimental morphologies of four MCF10A-derived cell lines carrying different oncogenic mutations onto the model parameter space, we identified changes in cellular processes potentially underlying structural modifications of these mutants. As a case study, we focused on MCF10A cells expressing an oncogenic mutant HER2-YVMA to quantitatively assess changes in cell doubling time, cell apoptotic rate, and cell sensitivity to ECM accumulation when compared to the parental non-tumorigenic cell line. By mapping in vitro mutant morphologies onto in silico ones we have generated a means of linking the morphological and molecular scales via computational modeling. Thus, IBCell in combination with 3D acini cultures can form a computational/experimental platform for suggesting the relationship between the histopathology of neoplastic lesions and their underlying molecular defects.