11 research outputs found
Oleate but not stearate induces the regulatory phenotype of myeloid suppressor cells
Tumor infiltrating myeloid cells play contradictory roles in the tumor
development. Dendritic cells and classical activated macrophages support anti-
tumor immune activity via antigen presentation and induction of pro-
inflammatory immune responses. Myeloid suppressor cells (MSCs), for instance
myeloid derived suppressor cells (MDSCs) or tumor associated macrophages play
a critical role in tumor growth. Here, treatment with sodium oleate, an
unsaturated fatty acid, induced a regulatory phenotype in the myeloid
suppressor cell line MSC-2 and resulted in an increased suppression of
activated T cells, paralleled by increased intracellular lipid droplets
formation. Furthermore, sodium oleate potentiated nitric oxide (NO) production
in MSC-2, thereby increasing their suppressive capacity. In primary polarized
bone marrow cells, sodium oleate (C18:1) and linoleate (C18:2), but not
stearate (C18:0) were identified as potent FFA to induce a regulatory
phenotype. This effect was abrogated in MSC-2 as well as primary cells by
specific inhibition of droplets formation while the inhibition of de novo FFA
synthesis proved ineffective, suggesting a critical role for exogenous FFA in
the functional induction of MSCs. Taken together our data introduce a new
unsaturated fatty acid-dependent pathway shaping the functional phenotype of
MSCs, facilitating the tumor escape from the immune system
Disentangling Electronic and Geometric Effects in Electrocatalysis through Substitution in Isostructural Intermetallic Compounds
Efficient development of catalytic materials requires knowledge of the decisive parameters defining the catalytic properties. In multicomponent metallic catalysts, these are categorized as electronic and geometric effects, yet they are strongly interrelated. A systematic disentanglement can be achieved by fixing one parameter while altering the other, which becomes possible through the substitution in isostructural intermetallic compounds. This approach enables the evaluation of electronic or geometric contributions both individually and combined. Herein, this is achieved by substitution of indium (three valence electrons) with tin (four valence electrons) in the series In(1-x)SnxPd(2), which allows for a systematic variation of the total number of electrons per unit cell with only a minor variation of the unit cell parameters and thus the evaluation of the electronic effect. Geometric effects were evaluated by substitution of indium with gallium in the Ga(1-x)InxPd(2) series, which allows for a systematic variation of the interatomic distances while maintaining the same number of valence electrons per unit cell and close atomic coordinates. By substituting gallium with tin in the Ga(1-x)SnxPd(2) series, both effects are combined and addressed simultaneously. The activity enhancement of the methanol oxidation reaction on the Ga(1-x)SnxPd(2) series is attributed to the synergy of the combined effects