Activity of Monosaccharide Lipid A Analogues in Human Monocytic Cells as Agonists or Antagonists of Bacterial Lipopolysaccharide

Abstract

The lipid A portion of bacterial lipopolysaccharide (LPS) plays a central role in the production of endotoxic mediators. Different responses between human and murine macrophages to lipid A-like structures have been indicated. We investigated a series of structurally related monosaccharide lipid A analogues for their potency to activate human macrophage U937 cells and peripheral blood mononuclear cells for production of tumor necrosis factor-␣ and interleukin-6 compared with their potency to activate murine macrophage RAW264.7 cells. Two of the analogues were found to have sufficient potency to activate the human cells as well as the murine cells. These analogues comprise D-glucosamine, phosphoryl groups, and acyl groups of defined carbon chain lengths (C 14 and C 12 ) in a ratio of 1:1:3. This ratio of molecular constituents is proportional to that of the complete disaccharide structure of lipid A (2:2:6). Other analogues with two or four C 14 acyl groups and with three acyl groups but including a C 10 or a C 16 acyl group, which are active to murine cells, showed no LPS-agonistic activity, but did show LPS-antagonistic activity, to human cells. An LPS-antagonistic analogue in the murine cells also showed antagonistic activity in human cells. These results reveal that lipid A analogues recognized as being LPS agonists by human macrophages have common structural features in monosaccharide and disaccharide structures which are more strict than those required for recognition by murine macrophages and that broad lipid A-like structures are recognized as being LPS antagonists by human cells but are recognized by murine cells as being either LPS agonists or antagonists. by guest http://iai.asm.org/ Downloaded from FIG. 6. Structures of synthetic lipid A analogues in relation to their LPS-agonistic and -antagonistic actions in murine and human macrophages (M).

A cyanobacterial LPS antagonist prevents endotoxin shock and blocks sustained TLR4 stimulation required for cytokine expression

“…These fall in two broad categories: receptor antagonists and LPS-neutralizing molecules. Among the fi rst are LPS-like molecules isolated from bacteria (Rhodobacter capsulatus and sphaeroides, Porphyromonas gingivalis, and Helicobacter pylori), deacylated LPS, lipid IVa, synthetic Lipid A analogues (including E5531, E5564, DT-5461, and GLA-47), and certain cationic peptides (40)(41)(42)(43)(44)(45)(46)(47)(48)(49). LPS-neutralizing molecules include polymixin B and synthetic peptides (50)(51)(52).…”

Characterization of complex, heterogeneous lipid A samples using HPLC–MS/MS technique I. Overall analysis with respect to acylation, phosphorylation and isobaric distribution

“…[65,66] Studies of the biological activities of monosaccharide-type lipid A analogues have identified the most agonistic character attributed to the tri-acylated lipid A partial structure, which is monophosphorylated at the C4 position and acylated by C14:0(3-OH) at the C3 and C2 positions with a branched C12:0 connected to the ester-linked primary fatty acid. [67][68][69] In all samples, the predominant species with the highest chromatographic peak was the hexa-acylated monophosphorylated lipid A at m/z 1716. The area of this peak was used to quantitate the lipid A mixtures.…”

Separation of 6-deoxy-heptane from a smooth-type lipopolysaccharide preparation of Burkholderia pseudomallei

“…Mouse and human macrophage cell lines, RAW264.7 (from the American Type Culture Collections, Rockville, MD, USA) and U937 (from the Japanese Cancer Research Resources Bank, Tokyo, Japan), respectively, were used as target macrophages for activation. Cells were cultured and stimulated as described in the previous papers [11,12]. Tumor necrosis factor (TNF) production in the culture supernatant was measured by a cytotoxic assay against L-929 cells [13].…”