title: Synthetic analogues of the bacterial signal (quorum sensing) molecule N-(3-oxododecanoyl)-L-homoserine lactone as immune modulators.
abstract: Comparative immune modulatory activity for a range of synthetic analogues of a Pseudomonas aeruginosa signal molecule, N-(3-oxododecanoyl)-l-homoserine lactone (3O, C(12)-HSL), is described. Twenty-four single or combination systematic alterations of the structural components of 3O, C(12)-HSL were introduced as described. Given the already defined immunological profile of the parent compound, 3O, C(12)-HSL, these compounds were assayed for their ability to inhibit murine and human leucocyte proliferation and TNF-alpha secretion by lipopolysaccharide (LPS) stimulated human leucocytes in order to provide an initial structure-activity profile. From IC(50) values obtained with a murine splenocyte proliferation assay, it is apparent that acylated l-homoserine lactones with an 11-13 C side chain containing either a 3-oxo or a 3-hydroxy group are optimal structures for immune suppressive activity. These derivatives of 3O, C(12)-HSL with monounsaturation and/or a terminal nonpolar substituent on the side chain were also potent immune suppressive agents. However, structures lacking the homoserine lactone ring, structures lacking the l-configuration at the chiral center, and those with polar substituents were essentially devoid of activity. The ability of compounds selected from the optimal activity range to modulate mitogen-driven human peripheral blood mononuclear cell proliferation and LPS-induced TNF-alpha secretion indicates the suitability of these compounds for further investigation in relation to their molecular mechanisms of action in TNF-alpha driven immunological diseases, particularly autoimmune diseases such as psoriasis, rheumatoid arthritis, and type 1 (autoimmune) diabetes.
authors.affiliation: School of Pharmaceutical Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
authors.forename: Siri Ram
authors.initials: SR
authors.lastname: Chhabra
authors.forename: Chris
authors.initials: C
authors.lastname: Harty
authors.forename: Doreen S W
authors.initials: DS
authors.lastname: Hooi
authors.forename: Mavis
authors.initials: M
authors.lastname: Daykin
authors.forename: Paul
authors.initials: P
authors.lastname: Williams
authors.forename: Gary
authors.initials: G
authors.lastname: Telford
authors.forename: David I
authors.initials: DI
authors.lastname: Pritchard
authors.forename: Barrie W
authors.initials: BW
authors.lastname: Bycroft
mesh_terms: D000276:Adjuvants, Immunologic / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D006714:Homoserine / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007783:Lactones / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D018375:Neutrophil Activation; D011550:Pseudomonas aeruginosa; D013154:Spleen / Q000166:cytology / Q000187:drug effects; D013329:Structure-Activity Relationship; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D000276:Adjuvants, Immunologic; D007783:Lactones; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; C085113:Pseudomonas aeruginosa autoinducer; D006714:Homoserine