Recognition in the lipopolysaccharicle (LPS), a major part of your outer membrane of Gram-negative bacteria, www.selleckchem.com/products/Epothilone-B.html by the Toll-like receptor four (TLR4)-myeloid differentiation component 2 (MD-2) complex is vital for the management of bacterial infection. A pro-inflammatory signaling cascade is initiated on binding of membrane-associated portion of LPS, a glycophospholipid Lipid A, by a coreceptor protein MD-2, which results inside a protective host innate immune response. Nonetheless, activation of TLR4 signaling by LPS may perhaps bring about the dysregulated immune response leading to a range of inflammatory ailments such as sepsis syndrome. Knowing of structural prerequisites for Lipid A endotoxicity would be certain the development of efficient anti-inflammatory drugs.
Herein, we report on design, synthesis, Interleukin-4 receptor and biological routines of a series of conformationally confined Lipid A mimetics according to beta,alpha-trehalose-type scaffold. Substitute with the flexible three-bond beta(one -> 46) linkage in diglucosamine backbone of Lipid A by a two-bond beta,alpha(1 <-> 1) glycosidic linkage afforded novel potent TLR4 antagonists. Synthetic tetraacylated bisphosphorylated Lipid A mimetics dependant on a beta-GlcN(one <-> 1)alpha-GlcN scaffold selectively block the LPS binding site on both human and murine MD-2 and completely abolish lipopolysaccharide-induced pro-inflammatory signaling, thereby serving as antisepsis drug candidates. In contrast to their natural counterpart lipid IVa, conformationally constrained Lipid A mimetics do not activate mouse TLR4. The structural basis for high antagonistic activity of novel Lipid A mimetics was confirmed by molecular dynamics simulation. Our findings suggest that http://www.selleckchem.com/Serotonin-receptor.html besides the chemical structure, also the three-dimensional arrangement in the diglucosamine backbone of MD-2-bound Lipid A determines endotoxic effects on TLR4.