ABSTRACT
LAS200813 is a novel bicyclic lipopeptide that activates Nrf2 by binding to Keap1, thereby antagonising the Keap1-Nrf2 protein-protein interaction. In this work we report the pharmacological characterization of LAS200813 in Nrf2-dependent translational preclinical models. LAS200813 binds to Keap1 with high affinity (IC50: 0.73 nM) and is able to induce the translocation of Nrf2 to the nucleus. Furthermore, LAS200813 increases the expression of Nrf2 target genes in human bronchial epithelial cells (EC50 of 96 and 70 nM for srxn1 and nqo1, respectively). Similarly, the intratracheal administration of LAS200813 to rats increases the expression of Nrf2-dependent genes in lung tissue, an effect that lasts for a few hours. Moreover, in cells exposed to cigarette smoke, LAS200813 shows an antioxidant effect by increasing the production of glutathione and prevents cellular apoptosis. In conclusion, the results described herein demonstrate that LAS200813 is a potent non-electrophilic Nrf2-activating peptide designed to be administered by inhaled route which may be a potential therapeutic strategy for respiratory diseases driven by oxidative stress.
Subject(s)
Antioxidants , Kelch-Like ECH-Associated Protein 1 , Lipopeptides , NF-E2-Related Factor 2 , Animals , Antioxidants/pharmacology , Glutathione/metabolism , Humans , Kelch-Like ECH-Associated Protein 1/metabolism , Lipopeptides/pharmacology , NF-E2-Related Factor 2/metabolism , Oxidative Stress , RatsSubject(s)
Disulfides/chemistry , Peptides/chemistry , Peptides/therapeutic use , Animals , Humans , Peptides/pharmacologyABSTRACT
Cys-disulfide bonds contribute to the stabilization of peptide and protein structures. The synthesis of these molecules requires a proper protection of Cys residues, which is crucial to prevent side-reactions and also to achieve the correct Cys connectivity. Here we undertook a mechanistic study of a set of well-known acid-labile Cys protecting groups, as well other new promising groups, in order to better understand the nature of their acid-lability. The stability of the carbocation generated during the acid treatment was found to have a direct impact on the removal of the protective groups from the corresponding protected Cys-containing peptides. Hence a combination of steric and conjugative effects determines the stability of the carbocations generated. Here we propose diphenylmethyl (Dpm) as a promising protecting group on the basis of its intermediate relative carbocation stability. All the optimized geometries and energies presented in this study were determined using a B3LYP/6-31G(d,p) calculation. The results discussed herein may be of broader applicability for the development of new protecting groups.
Subject(s)
Cysteine/chemistry , Peptides/chemistry , Peptides/chemical synthesisABSTRACT
Protected peptide fragments are valuable building blocks for the assembly of large peptide sequences through fragment condensation approaches, whereas protected peptides are typically synthesized for the preparation of amide-bridge cyclic peptides in solution. Efficient synthesis of both protected peptides and protected peptide fragments by solid-phase peptide synthesis methodology requires handles that attach the growing peptides to the polymeric support and can be cleaved under appropriate conditions, while maintaining intact the side-chain protecting groups. Here, we provide an overview of attachment methods described in the literature for the preparation of protected peptides using Fmoc/tBu chemistry, including the most commonly used acid-labile linkers along with the most recent and sophisticated.
Subject(s)
Amino Acids/chemistry , Fluorenes/chemistry , Peptides/chemical synthesis , Solid-Phase Synthesis TechniquesABSTRACT
Irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation (CIC) are highly prevalent gastrointestinal disorders associated with health, economical and social problems. Recently, after a long journey of preclinical studies and clinical trials, linaclotide, a first-in-class GC-C receptor peptide agonist, has received the approval in the USA and Europe for the treatment of IBS-C and CIC. This article provides an overview of clinical, economic and biological aspects of IBS-C and CIC and covers the current and emerging therapeutic agents for treating these conditions. Particularly, the pharmacodynamic and pharmacokinetic properties of linaclotide, a small, disulfide-rich peptide, and its implications in the future of peptide drug discovery and development are discussed.
Subject(s)
Constipation/complications , Constipation/drug therapy , Irritable Bowel Syndrome/complications , Irritable Bowel Syndrome/drug therapy , Peptides/therapeutic use , Receptors, Guanylate Cyclase-Coupled/agonists , Receptors, Peptide/agonists , Amino Acid Sequence , Animals , Chronic Disease , Colon/pathology , Constipation/economics , Constipation/pathology , Humans , Irritable Bowel Syndrome/economics , Irritable Bowel Syndrome/pathology , Models, Molecular , Molecular Sequence Data , Peptides/chemistry , Peptides/pharmacokinetics , Peptides/pharmacology , Receptors, Enterotoxin , Receptors, Guanylate Cyclase-Coupled/metabolism , Receptors, Peptide/metabolismABSTRACT
Enzyme-labile protecting groups have emerged as a green alternative to conventional protecting groups. These groups introduce a further orthogonal dimension and eco-friendliness into protection schemes for the synthesis of complex polyfunctional organic molecules. S-Phacm, a Cys-protecting group, can be easily removed by the action of a covalently immobilized PGA enzyme under very mild conditions. Herein, the versatility and reliability of an eco-friendly combination of the immobilized PGA enzyme and the S-Phacm protecting group has been evaluated for the synthesis of diverse Cys-containing peptides.
Subject(s)
Cysteine/chemistry , Enzymes, Immobilized/chemistry , Enzymes, Immobilized/chemical synthesis , Escherichia coli/chemistry , Penicillin Amidase/chemistry , Peptides/chemistry , Peptides/chemical synthesis , Green Chemistry Technology , Molecular StructureABSTRACT
To address the existing gap in the current set of acid-labile Cys-protecting groups for the Fmoc/tBu strategy, diverse Fmoc-Cys(PG)-OH derivatives were prepared and incorporated into a model tripeptide to study their stability against TFA. S-Dpm proved to be compatible with the commonly used S-Trt group and was applied for the regioselecive construction of disulfide bonds.
Subject(s)
Cysteine/chemistry , Fluorenes/chemistry , Amino Acids/chemistry , Combinatorial Chemistry Techniques , Cysteine/analogs & derivatives , Models, Molecular , Molecular Structure , Peptides/chemistryABSTRACT
A new universal strategy exploits DKP formation in a dipeptide moiety whose C-terminal residue is blocked by a leaving group. It enables both synthesis of C-terminal protected peptides that are useful for convergent synthesis of large peptides and use of a C-terminal permanent protecting group that can be cleaved by catalytic hydrogenation to release the peptide.
Subject(s)
Peptides/chemical synthesis , Amino Acid Sequence , Catalysis , Click Chemistry , Hydrogenation , Peptides/chemistry , Solid-Phase Synthesis TechniquesABSTRACT
Linaclotide, a small 14-mer peptide highly rich in cysteines, is currently in phase III clinical trials for the treatment of gastrointestinal disorders. The challenge in the assembly of linaclotide consists of achieving the correct and clean folding of its three disulfide bridges. For this purpose, a number of regioselective, semiregioselective, and random strategies have been studied. In addition to selecting distinct protecting groups for the thiol function, their position in the sequence, the influence of the neighboring protecting groups, as well as the order in which the disulfides fold were studied. Here we describe an optimized solid-phase synthesis of linaclotide that should allow the production of this peptide in multigram amounts.
