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Biomedical subjects

R Vanderesse

Publications and source records attributed to R Vanderesse.

7 recordsLinked to original sources

The immunostimulatory peptide WKYMVm-NH activates bone marrow mouse neutrophils via multiple signal transduction pathways.

G-protein-coupled receptors play a major role in the activation of the innate immune system, such as polymorphonuclear neutrophils. Members of the formyl peptide receptor family recognize chemotactic peptides as well the amyloïd-beta peptide and fragments of the human immunodeficiency virus envelope and may thus be implicated in major pathologies. The peptide WKYMVm-NH2 probably activates the receptor FPRL1 and its mouse orthologues Fpr-rs1 and Fpr-rs2. We examined the stimulation of C57BL6 mouse neutrophils by WKYMVm-NH2 and the effects of several inhibitors for intracellular signalling pathways (wortmannin, LY 294002, staurosporin, H-89, U 73122, thapsigargin and SKF 96365). We show here that WKYMVm-NH2 is a powerful stimulator of primary and secondary granule exocytosis as well as superoxide production. The signalling pathway involves phosphoinositide 3-kinase, protein kinase C, phospholipase C and store-operated calcium influx. Studies with peptide antagonists suggest that WKYMVm-NH2 preferentially activates exocytosis via FPRL1 and not FPR, the major receptor for N-formylated peptides such as fMLF. However, the signalling pathways activated by WKYMVm-NH2 in mouse neutrophils are similar to those activated by fMLF in human neutrophils. Thus, the effect and the signalling pathways of the two agonists and their receptors are at least partially overlapping.

1-Phosphatidylinositol 4-Kinase↗

Applicability of predictive models to the peptide mobility analysis by capillary electrophoresis-electrospray mass spectrometry.

The prediction of peptide mobility by capillary electrophoresis (CE) coupled to electrospray mass spectrometry (MS) is studied in order to verify the validity of the semi-empirical models developed in classical CE. This work relies on the experimental determination of the electrophoretic mobilities of 68 peptides, different in charge and in size. The results indicate that the prediction is possible in CE-MS experiments, in spite of the restraints inherent in the coupling conditions. The best fit of experimental data was obtained with the Offord's model. The efficiency of the model was confirmed by the analysis of a peptide mixture in CE-MS.

Amino Acid Sequence↗

Structure of epitopes recognized by the antibodies to alpha(181-192) peptides of neuronal nicotinic acetylcholine receptors: extrapolation to the structure of acetylcholine-binding domain.

Using the alpha(181-192) peptides of neuronal nicotinic acetylcholine receptor (nAChR) and Ala-substituted peptide analogues, amino acid residues critical for specific monoclonal antibody (mAb) binding were identified. By means of 2D nuclear magnetic resonance (2D-NMR) analysis followed by molecular modeling, it was found that mAb binding resulted in stabilization of the free alpha3(181-192) peptide flexible conformation yielding an extended structure with residues 6-11 of the peptide being in direct contact with the Ab. Since the Ab binds the native AChR as well, it is suggested that the corresponding fragment of AChR alpha3 subunit is exposed to solution and also appears in extended conformation.

Alanine↗

Piv-Propsi

The pseudodipeptide, (S)-N-isopropyl [N-(pivaloyl)pyrrolidin-2-yl]methylaminooxyacetamide, C(15)H(29)N(3)O(3), adopts a global extended conformation with the hydroxylamine group in the g(+)/g(-) structure. The C-terminal amide NH interacts intramolecularly with the hydroxylamine O atom. Both NH bonds of each molecule are hydrogen bonded to the C-terminal amide carbonyl of a neighbouring molecule.

Journal Article↗

Two-dimensional 1H-NMR and CD structural analysis in a micellar medium of a bovine alphaS1-casein fragment having benzodiazepine-like properties.

The conformation of the benzodiazepine-like decapeptide, YLGYLEQLLR, corresponding to residues 91-100 of bovine alphaS1-casein, has been examined in SDS micelles using CD, two-dimensional 1H-NMR and restrained molecular-dynamics simulation. Evidence is presented that the decapeptide adopts a rigid structure in water/SDS micellar medium, but not in water or dimethylsulfoxide. The three-dimensional structure, consistent with the proton-proton distances obtained from the quantitative analysis of the two-dimensional NOEs, was generated by restrained energy minimization and molecular-dynamics simulation. In water/SDS micellar medium, YLGYLEQLLR adopts an amphipathic helicoid structure with distinct hydrophobic and hydrophilic faces. The relative disposition of the tyrosine aromatic rings was compared with that of the aromatic rings in the benzodiazepines.

Animals↗

Production of antibodies to alpha(181-192) peptides of neuronal nicotinic acetylcholine receptor coupled to protein carriers in different orientations.

The antibodies to nicotinic acetylcholine receptor alpha(181-192) synthetic peptides were elicited in rabbits and mice using the peptides conjugated to protein carriers in different orientations, either through C-terminal Cys (S-conjugates), or through amino groups (N-conjugates). S-conjugated peptides were less potent in eliciting peptide-specific antibodies compared to N-conjugates and this type of conjugation resulted in antibodies to the coupling reagent. However, the epitopes present in either S- or N-conjugated peptides appeared to be similar, indicating that amino acid residues, which form the epitope, were located in the middle part of the peptide and did not include both N- and C-terminal residues. Peptide conjugation to a protein carrier did not play a role in stabilizing the peptide conformation, but was necessary to concentrate the peptide epitopes on the carrier surface enabling bivalent antibody binding.

Amino Acid Sequence↗