A Functionalized 8 nm Long Aryleneethynylene Molecular Wire with Alkyne Termini.

The synthesis of new conjugated aryleneethynylene derivatives of up to ca. 8 nm molecular length (compound 16) with terminal alkyne substituents and 9,9-dihexylfluorene units in the backbone is described. Key synthetic steps are Pd-mediated Sonogashira coupling methodology combined with regioselective removal from the terminal alkyne units of 2-hydroxy-2-propyl protecting groups in the presence of trimethylsilyl groups. The structural and electronic properties of 16 were obtained from DFT calculations: the intramolecular terminal C···C distance in its relaxed conformation was found to be 7.8 nm. The calculated distribution of HOMO and LUMO orbitals and the strong blue fluorescence observed for 16 (max = 420, 443 nm in CHCl3 solution) are consistent with a highly conjugated penta[(9,9-dihexyl-2,7-fluorenylene)ethynylene] structure. Molecule 16 possesses multifunctionality and is of interest for future molecular electronic device applications

Sphingosine-1-phosphate promotes the persistence of activated CD4 T cells in inflamed sites

Inflammation can be protective or pathogenic depending on context and timeframe. Acute inflammation, including the accumulation of CD4 T cells, accompanies protective immune responses to pathogens, but the presence of activated CD4 T cells at sites of inflammation is associated with chronic inflammatory disease. While significant progress has been made in understanding the migration of CD4 T cells into inflamed sites, the signals that lead to their persistence are poorly characterized. Using a murine ear model of acute inflammation and intravital two-photon imaging, we have dissected the signals that mediate CD4 T cell persistence. We report the unexpected finding that the bioactive lipid, sphingosine-1-phosphate (S1P), is both necessary and sufficient for the persistence of activated CD4 T cells at peripheral tissues in acute inflammation. S1P mediated the enhanced motility of CD4 T cells at inflamed tissues but did not affect their migration to the downstream draining lymph node. We found that sphingosine kinase-1, which regulates S1P production is increased at inflamed sites in mice and in patients with the chronic inflammatory disease, rheumatoid arthritis. Together, these data suggest that S1P, or its regulators, may be key targets to promote or disrupt accumulation of CD4 T cells at inflamed tissues

School of Naval Warfare: Flexibility—Key to Overseas Support

The term overseas support as used herein will have broader application. In addition to mobile sea and air support, it embraces each type of military shore facility supporting our national interests from the smallest resident office or antenna site to tbe sprawling, multipurpose naval base

Sphingosine-1-phosphate receptor-1 (S1P1) is expressed by lymphocytes, dendritic cells, and endothelium and modulated during inflammatory bowel disease

The sphingosine-1-phosphate receptor-1 (S1P1) agonist ozanimod ameliorates ulcerative colitis, yet its mechanism of action is unknown. Here, we examine the cell subsets that express S1P1 in intestine using S1P1-eGFP mice, the regulation of S1P1 expression in lymphocytes after administration of dextran sulfate sodium (DSS), after colitis induced by transfer of CD4+CD45RBhi cells, and by crossing a mouse with TNF-driven ileitis with S1P1-eGFP mice. We then assayed the expression of enzymes that regulate intestinal S1P levels, and the effect of FTY720 on lymphocyte behavior and S1P1 expression. We found that not only T and B cells express S1P1, but also dendritic (DC) and endothelial cells. Furthermore, chronic but not acute inflammatory signals increased S1P1 expression, while the enzymes that control tissue S1P levels in mice and humans with inflammatory bowel disease (IBD) were uniformly dysregulated, favoring synthesis over degradation. Finally, we observed that FTY720 reduced T-cell velocity and induced S1P1 degradation and retention of Naïve but not effector T cells. Our data demonstrate that chronic inflammation modulates S1P1 expression and tissue S1P levels and suggests that the anti-inflammatory properties of S1PR agonists might not be solely due to their lymphopenic effects, but also due to potential effects on DC migration and vascular barrier function

Mechanisms of T cell organotropism

F.M.M.-B. is supported by the British Heart Foundation, the Medical Research Council of the UK and the Gates Foundation

Chemokines control naive CD8+ T cell selection of optimal lymph node antigen presenting cells

CCR5-binding chemokines produced in the draining lymph node after vaccinia virus infection guide naive CD8+ T cells toward DCs and away from the macrophage-rich zone, thereby facilitating optimal CD8+ T cell activation and cytokine production