Interaction of Polysialic Acid with CCL21 Regulates the Migratory Capacity of Human Dendritic Cells

Dendritic cells (DCs) are the most potent antigen-presenting cells (APCs). Immature DCs (iDCs) are situated in the periphery where they capture pathogen. Subsequently, they migrate as mature DCs (mDCs) to draining lymph nodes to activate T cells. CCR7 and CCL21 contribute to the migratory capacity of the DC, but it is not completely understood what molecular requirements are involved. Here we demonstrate that monocyte-derived DCs dramatically change ST8Sia IV expression during maturation, leading to the generation of polysialic acid (polySia). PolySia expression is highly upregulated after 2 days Toll-like receptor-4 (TLR4) triggering. Surprisingly, only immunogenic and not tolerogenic mDCs upregulated polySia expression. Furthermore, we show that polySia expression on DCs is required for CCL21-directed migration, whereby polySia directly captures CCL21. Corresponding to polySia, the expression level of CCR7 is maximal two days after TLR4 triggering. In contrast, although TLR agonists other than LPS induce upregulation of CCR7, they achieve only a moderate polySia expression. In situ we could detect polySia-expressing APCs in the T cell zone of the lymph node and in the deep dermis. Together our results indicate that prolonged TLR4 engagement is required for the generation of polySia-expressing DCs that facilitate CCL21 capture and subsequent CCL21-directed migration

Goat and buffalo milk fat globule membranes exhibit better effects at inducing apoptosis and reduction the viability of HT-29 cells

Bovine milk fat globule membrane (MFGM) has shown many health benefits, however, there has not been much study on non-cattle MFGMs. The purpose of this study was to compare the anti-proliferation effects and investigate the mechanisms of MFGMs from bovine, goat, buffalo, yak and camel milk in HT-29 cells. Results showed that protein content in MFGM of yak milk is the highest among five MFGM. All MFGMs inhibited cellular proliferation which was in agreement with cell morphology and apoptosis. However, the number of cells in S-phase from 24 h to 72 h was increased significantly by treatment with goat, buffalo and bovine MFGMs (100 μg/mL), but not yak and camel. All MFGMs treatment significantly reduced the mitochondrial membrane potential (with an order of goat>buffalo>bovine>camel>yak) and Bcl-2 expression, but increased the expression of both Bax and Caspase-3. Taken together, the results indicate that all MFGMs, especially goat and buffalo MFGMs, showed better effects at inducing apoptosis and inhibition of the proliferation of HT-29 cells. The mechanism might be arresting the cell cycle at S phase, depolarization of mitochondrial membrane potential, down-regulation of Bcl-2 expression and increase of Bax and Caspase-3 expression

Metallacrowns as products of the aqueous medium self-assembly of histidinehydroxamic acid-containing polypeptides.

Self-assembly is a widely studied, spontaneous, and reversible phenomenon leading to the formation of the ordered structures by non-covalent specific interactions among starting molecules. In this work, a new template for the self-assembly of polypeptides based on peptides containing the C-terminal histidinehydroxamic acid moiety and Cu2+ ions is characterized. Two peptide (tripeptide and pentadecapeptide) hydroxamic acid systems were synthesized and their interactions with Cu2+ ions were investigated, revealing a high stability of the supramolecular assemblies formed. The supramolecular metallacrown-based L4Cu5 complexes exist at physiological pH in the presence of Cu2+ ions as is evidenced from the spectroscopic methods, ESI mass spectrometry, and physicochemical techniques

Shaping of a ground state rotational wavepacket by frequency-chirped pulses

0953-4075A coherent rotational superposition state is produced in the ground vibronic level of N2 through the interaction of the molecule with the electric field vector of a nonresonant laser pulse. This rotational wavepacket is shaped with a linear frequency chirp of the laser field. The structural shape of the rotational coherences shows a strong dependence with the frequency-chirp amplitude. A comparison with a theoretical model allows the interpretation of the observed effects in terms of dephasing of the wavepacket induced by the laser phase distortion. Application of the presented results to the phase characterization of short XUV pulses is suggested