Synthesis and Toll-like Receptor 4 (TLR4) Activity of Phosphatidylinositol Dimannoside Analogues

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• 作者：Gary D. Ainge ; William John Martin ; Benjamin J. Compton ; Colin M. Hayman ; David S. Larsen ; Sung-il Yoon ; Ian A. Wilson ; Jacquie L. Harper ; Gavin F. Painter
• 刊名：Journal of Medicinal Chemistry
• 出版年：2011
• 出版时间：October 27, 2011
• 年：2011
• 卷：54
• 期：20
• 页码：7268-7279
• 全文大小：1086K
• 年卷期：v.54,no.20(October 27, 2011)
• ISSN：1520-4804

文摘

A series of five PIM₂ analogues were synthesized and tested for their ability to activate primary macrophages and modulate LPS signaling. Structural changes included replacement of the fatty acid esters of the phosphatidyl moiety of PIM₂ with the corresponding ether or amide. An AcPIM₂ analogue possessing an ether linkage was also prepared. The synthetic methodology utilized an orthogonally protected chiral myo-inositol starting material that was conveniently prepared from myo-inositol in just two steps. Important steps in the synthetic protocols included the regio- and 伪-selective glycosylation of inositol O-6 and introduction of the phosphodiester utilizing phosphoramidite chemistry. Replacement of the inositol core with a glycerol moiety gave compounds described as phosphatidylglycerol dimannosides (PGM₂). Biological testing of these PIM compounds indicated that the agonist activity was TLR4 dependent. An ether linkage increased agonist activity. Removal of the inositol ring enhanced antagonist activity, and the presence of an additional lipid chain enhanced LPS-induced cytokine production in primary macrophages. Furthermore, the interruption of the LPS-induced 2:2 TLR4/MD-2 signaling complex formation by PIM₂ represents a previously unidentified mechanism involved in the bioactivity of PIM molecules.