Design and synthesis of peptide and non-peptide analogues of myelin epitopes for the immunotherapy of multiple sclerosis

The aim of this thesis was to immunologically control the attack of myelin sheath in MS patients without the total suppression of the immune system. The thesis was focused on the synthesis of the following molecules: (a) Linear peptide analogues based on myelin epitopes (Table 1). (b) Linear and cyclic peptide analogues conjugated with mannan via the decapeptide (Lys-Gly)5 as a bridge (Table 2, 4). (c) A polypeptide, based on copolymer-1, conjugated with mannan via the decapeptide (Lys-Gly)5 as a bridge (Table 2, 4). (d) Peptide dendrimers (MAPs) conjugated with mannan via the tetrapeptide (Lys-Gly)2 as a bridge (Table 3, 4). (e) Anthraquinone type analogues (Fig. 1) in combination with peptide analogues (Fig. 2). The synthesis of peptide analogues was achieved either conventionally or with microwave irradiation. The resins utilized were CLTR-Cl, Wang and NovaSynTGA, which are combined with Fmoc/tBu methodology. The conjugation of peptides with mannan was performed in solution, while the reaction was monitored with RP-HPLC.Κατά την εκπόνηση της παρούσας διατριβής έγινε προσπάθεια, με βάση την κατανόηση της παθοφυσιολογίας της ΣΚΠ, να ελεγχθεί η ανοσολογική επίθεση στη μυελίνη, χωρίς να κατασταλεί ευρύτερα το ανοσοποιητικό σύστημα. Συγκεκριμένα, έγιναν: (α) Σύνθεση γραμμικών πεπτιδικών αναλόγων, τα οποία είναι υπεύθυνα για εμφάνιση ΣΚΠ (Πίνακας 1). (β) Σύνθεση πεπτιδικών αναλόγων, γραμμικών και κυκλικών, που φέρουν το δεκαπεπτίδιο (Lys-Gly)5 ως γέφυρα σύνδεσης με τον πολυσακχαρίτη μαννάνη (Πίνακας 2). (γ) Σύνθεση πολυπεπτιδίου με βάση το copolymer-1 και το δεκαπεπτίδιο (Lys-Gly)5 ως γέφυρα σύνδεσης με τον πολυσακχαρίτη μαννάνη (Πίνακας 2). (δ) Σύνθεση πεπτιδικών δενδριμερών (MAPs) που φέρουν το τετραπεπτίδιο (Lys-Gly)2 ως γέφυρα σύνδεσης με τον πολυσακχαρίτη μαννάνη (Πίνακας 3). (ε) Σύνθεση αναλόγων ανθρακινονών (Σχ. 1) και σύζευξή τους με πεπτιδικά ανάλογα (Σχ. 2). Η σύνθεση των πεπτιδικών αναλόγων έγινε είτε με το συμβατικό τρόπο είτε με τη χρήση μικροκυμάτων. Οι ρητίνες που χρησιμοποιήθηκαν ήταν οι CLTR-Cl, Wang και NovaSynTGA, οι οποίες συνδυάζονται με την Fmoc/tBu μεθοδολογία. Μερικά από τα πεπτιδικά ανάλογα που συντέθηκαν συζεύχθηκαν με τον πολυσακχαρίτη μαννάνη στην οξειδωμένη και ανηγμένη μορφή του (Πίνακας 4). Η σύζευξη με τη μαννάνη έγινε σε υγρή φάση και ο έλεγχος της σύζευξης έγινε με RP-HPLC χρωματογραφία

Putative Bioactive Conformations of Amide Linked Cyclic Myelin Basic Protein Peptide Analogues Associated with Experimental Autoimmune Encephalomyelitis

The solution models of cyclo(87-99) MBP87-99, cyclo(87-99) [Ala91,96] MBP87-99, and cyclo(87-99) [Arg91, Ala96] MBP87-99 have been determined through 2D NMR spectroscopy in DMSO-d6. Chemical shift analysis has been performed in an attempt to elucidate structural changes occurring upon substitution of native residues. NMR-derived geometrical constraints have been used in order to calculate high-resolution conformers of the above peptides. Conformational analysis of the three synthetic analogues show that the bioactivity, or the lack of it, may possibly be due to the distinct local structure observed and the subsequent differences in the overall topology and exposed area after binding with Major Histocompatibility Complex II (MHC II). It is believed that an overall larger solvent accessible area blocks the approach and binding of the T-cell receptor (TCR) on the altered peptide ligand (APL)-MHC complex, whereas more compact structures do not occlude weak interactions with an approaching TCR and can cause Experimental Autoimmune Encephalomyelitis (EAE) antagonism. A pharmacophore model based on the structural data has been generated

Design, synthesis, and molecular modeling of a novel amide-linked cyclic GnRH analogue cyclo(4-9)[Lys(4),D-Trp(6),Glu(9)]GnRH: Stimulation of gonadotropin gene expression

Journal URL: http://pubs.acs.org/journals/jmcmar/index.htm

Putative bioactive conformations of amide linked cyclic myelin basic protein peptide analogues associated with experimental autoimmune encephalomyelitis

The solution models of cyclo(87−99) MBP87-99, cyclo(87−99) [Ala91,96] MBP87-99, and cyclo(87−99) [Arg91, Ala96] MBP87-99 have been determined through 2D NMR spectroscopy in DMSO-d6. Chemical shift analysis has been performed in an attempt to elucidate structural changes occurring upon substitution of native residues. NMR-derived geometrical constraints have been used in order to calculate high-resolution conformers of the above peptides. Conformational analysis of the three synthetic analogues show that the bioactivity, or the lack of it, may possibly be due to the distinct local structure observed and the subsequent differences in the overall topology and exposed area after binding with Major Histocompatibility Complex II (MHC II). It is believed that an overall larger solvent accessible area blocks the approach and binding of the T-cell receptor (TCR) on the altered peptide ligand (APL)−MHC complex, whereas more compact structures do not occlude weak interactions with an approaching TCR and can cause Experimental Autoimmune Encephalomyelitis (EAE) antagonism. A pharmacophore model based on the structural data has been generated

Design, Synthesis, and Molecular Modeling of a Novel Amide-Linked Cyclic GnRH Analogue Cyclo(4-9)[Lys4,d-Trp6,Glu9]GnRH: Stimulation of Gonadotropin Gene Expression

This report describes the rational design, synthesis, and pharmacological properties of an amide-linked cyclic analogue of gonadotropin-releasing hormone (GnRH) namely Cyclo(4−9)[Lys4,d-Trp6,Glu9]GnRH. The conformationally restricted analogue is characterized by reduced flexibility of the peptide strand due to the introduction of a β-turn mimetic through 4,9 residue amide cyclization. The cyclic analogue was found to stimulate gonadotropin gene expression in the goldfish pituitary with similar potency compared to two native forms of GnRH. Simulation studies based on ROE connectivities in linear GnRH and potency of cyclic analogue supports the His2, Trp3, Tyr5 clustering considered important for triggering receptor activation