ABSTRACT
Chemokine receptors have gained attention as potential targets for novel therapeutic strategies. We investigated the mechanisms of allograft rejection in chemokine receptor Cxcr3-deficient mice using a model of acute heart allograft rejection in the strain combination BALB/c to C57BL/6. Allograft survival was minimally prolonged in Cxcr3-deficient mice compared to wild-type (wt) animals (8 vs. 7 days) and treatment with a subtherapeutic dose of cyclosporine A (CsA) led to similar survival in Cxcr3-deficient and wt recipients (13 vs. 12 days). At rejection grafts were histologically indistinguishable. Microarray analysis revealed that besides Cxcr3 only few genes were differentially expressed in grafts or in spleens from transplanted or untransplanted animals. Transcript analysis by quantitative RT-PCR of selected cytokines, chemokines, or chemokine receptors or serum levels of selected cytokines and chemokines showed similar levels between the two groups. Furthermore, in a rat heart allograft transplantation model treatment with a small molecule CXCR3 antagonist did not prolong survival despite full blockade of Cxcr3 in vivo. In summary, Cxcr3 deficiency or pharmacologic blockade does not diminish graft infiltration, tempo and severity of rejection. Thus, Cxcr3 does not appear to play a pivotal role in the allograft rejection models described here.
Subject(s)
Cyclosporine/administration & dosage , Graft Rejection , Graft Survival , Heart Transplantation/immunology , Receptors, CXCR3/metabolism , Animals , Mice , Mice, Inbred C57BL , Rats , Reverse Transcriptase Polymerase Chain Reaction , Transplantation, HomologousABSTRACT
The syntheses and the biological activities of 53-deoxo sanglifehrin A (2) and 61-deoxy octahydrosanglifehrin A (3) are described. Compound 2 shows intracellular cyclophilin (CyP)-binding and immunosuppressive activity in the mixed-lymphocyte reaction (MLR) similar to that of sanglifehrin A (1). Compound 3 is much less active in the MLR despite unchanged intracellular CyP-binding. This indicates that the 53-keto group is not necessary for immunosuppressive activity, while the 61 hydroxy group is required.
Subject(s)
Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/metabolism , Cyclophilins/metabolism , Lactones/chemistry , Lactones/metabolism , Spiro Compounds/chemistry , Spiro Compounds/metabolism , Animals , Cell Membrane Permeability/drug effects , Humans , Immunosuppressive Agents/chemistry , Immunosuppressive Agents/metabolism , Inhibitory Concentration 50 , Lymphocyte Culture Test, Mixed , Static Electricity , Structure-Activity RelationshipABSTRACT
Seven sLe(x) mimics where the -CH2OH group of the galactose moiety is replaced by -CH2NH3+, -CH2NHAc, -CH2NHBz, -CH2OSO3Na, -COONa and -CONH2 have been prepared and tested for their binding affinity to E-selectin.
Subject(s)
Oligosaccharides/chemical synthesis , E-Selectin/metabolism , Galactose , Oligosaccharides/metabolism , Sialyl Lewis X Antigen , Structure-Activity RelationshipABSTRACT
An early step of the inflammatory response-the rolling of leukocytes on activated endothelial cells-is mediated by selectin/carbohydrate interactions. The tetrasaccharide sialyl Lewis(x) (sLe(x)) 1 is a ligand for E-, P-, and L-selectin and, therefore, serves as a lead structure to develop analogues which allow the control of acute and chronic inflammation. Here we describe the efficient synthesis (10 linear steps) of the potent sLe(x) mimetic 2. Compared to sLe(x), compound 2 showed a 30-fold improved affinity in a static, cell-free E-selectin-ligand binding assay (IC(50) = 36 microM). These data were confirmed by a marked inhibition in an in vitro cell-cell rolling assay which simulates in vivo conditions (IC(50) approximately 40 microM). The assays are predictive for the in vivo efficacy of test compounds as indicated by a marked inhibitory effect of 2 in a thioglycollate induced peritonitis model of acute inflammation in mice (ED(50) approximately 15 mg/kg).
Subject(s)
E-Selectin/metabolism , Oligosaccharides/chemical synthesis , Acute Disease , Animals , Carbohydrate Sequence , Ligands , Mice , Molecular Mimicry , Molecular Sequence Data , Oligosaccharides/chemistry , Oligosaccharides/pharmacology , Peritonitis/chemically induced , Peritonitis/drug therapy , Sialyl Lewis X Antigen , Structure-Activity Relationship , ThioglycolatesABSTRACT
Four metabolites named peritoxins A and B and periconins A and B have been isolated together with the known metabolite circinatin from culture filtrates of the fungal pathogen Periconia circinata. Peritoxins A and B, which correspond to the P. circinata toxins Ia and IIa partially characterized in previous work, are selectively toxic to genotypes of Sorghum bicolor susceptible to the pathogen, whereas periconins A and B are biologically inactive. Combination of instrumental analysis and chemical degradation has led to structural assignments for each of the four compounds; only the configuration at some of the chiral centers remains undefined. Structural comparison suggests a precursor role for circinatin in the formation of the peritoxins and the periconins.
