ABSTRACT
The spiral shape of intestinal pathogen Campylobacter jejuni is critical for invasion of intestinal mucosa epithelial cells. Insofar as this cell morphology plays a role in the pathology of C. jejuni infection, its restructuring by pharmacological intervention could be an unexplored means to prevention of infection. We recently described that peptidoglycan hydrolase 3 (Pgp3) is involved in the spiral-shape formation of C. jejuni. We report herein the design and synthesis of the hydroxamate-based inhibitors targeting Pgp3. C. jejuni cells exposed to these inhibitors changed from the helical- to rod-shaped morphology, comparable to the case of the pgp3-deletion mutant. Evidence for the mechanism of action was provided by crystal structures of Pgp3 in complex with inhibitors, shedding light into the binding modes of inhibitors within the active site, supported by kinetics and molecular-dynamics simulations. C. jejuni exposed to these inhibitors underwent the morphological change from helical- to rod-shaped bacteria, an event that reduce the ability for invasion of the host cells. This proof of concept suggests that alteration of morphology affects the interference with the bacterial infection.
Subject(s)
Campylobacter Infections , Campylobacter jejuni , Campylobacter Infections/metabolism , Campylobacter Infections/microbiology , Campylobacter jejuni/metabolism , Epithelial Cells/metabolism , Humans , Intestinal Mucosa/metabolism , IntestinesABSTRACT
In an effort designed to discover superior inhibitors of cyclophilin D (CypD), we identified and screened members of a one-bead-one-compound (OBOC) library of cyclic peptoid analogues of cyclosporin A (CsA). The results show that the one member of this cyclic peptoid family, I11, inhibits mitochondrial membrane potential changes mediated by CypD.
Subject(s)
Enzyme Inhibitors/chemistry , Neuroprotective Agents/chemistry , Peptoids/chemistry , Small Molecule Libraries/chemistry , Animals , Biological Transport , Blood-Brain Barrier/metabolism , Cyclosporine/chemistry , Enzyme Inhibitors/pharmacology , High-Throughput Screening Assays , Humans , Membrane Potential, Mitochondrial , Mice , Mitochondria/metabolism , Neuroprotective Agents/pharmacology , Peptoids/pharmacology , Small Molecule Libraries/pharmacology , Structure-Activity RelationshipABSTRACT
The penetration of biological membranes is a prime obstacle for the delivery of pharmaceutical drugs. Cell-penetrating peptide (CPP) is an efficient vehicle that can deliver various cargos across the biological membranes. Since the discovery, CPPs have been rigorously studied to unveil the underlying penetrating mechanism as well as to exploit CPPs for various biomedical applications. This review will focus on the various strategies to overcome current limitations regarding stability, selectivity, and efficacy of CPPs.
Subject(s)
Cell-Penetrating Peptides/administration & dosage , Amino Acid Sequence , Cell Membrane/metabolism , Cell-Penetrating Peptides/chemistry , Drug Delivery Systems , Humans , Pore Forming Cytotoxic Proteins/administration & dosage , Pore Forming Cytotoxic Proteins/chemistryABSTRACT
We developed a pH-activatable cell-penetrating peptide dimer LH2 with histidine residues, which can penetrate cells, specifically in weak acidic conditions, even at few tens of nanomolar concentrations. LH2 effectively delivered paclitaxel into triple-negative breast cancer cells, MDA-MB-231, via formation of non-covalent complexes (PTX-LH2(M)) or covalent conjugates (PTX-LH2(C)). Moreover, LH2 showed prolonged circulation in the body and enhanced accumulation in tumors. Both PTX-LH2(M) and PTX-LH2(C) showed strong antitumor effects in a triple-negative breast cancer grafted mouse model at an extremely low dosage.
Subject(s)
Antineoplastic Agents , Breast Neoplasms , Cell-Penetrating Peptides , Pharmaceutical Preparations , Triple Negative Breast Neoplasms , Animals , Antineoplastic Agents/therapeutic use , Cell Line, Tumor , Cell-Penetrating Peptides/therapeutic use , Female , Humans , Hydrogen-Ion Concentration , Mice , Mice, Nude , Paclitaxel/therapeutic use , Triple Negative Breast Neoplasms/drug therapyABSTRACT
Gram-negative bacteria are becoming resistant to almost all currently available antibiotics. Systemically designed antimicrobial peptides (AMPs) are attractive agents to enhance the activities of antibiotics. We constructed a small Pro-scanning library using amphipathic model peptides. Measurements of minimum inhibitory concentration (MIC) against Escherichia coli and hemolytic activities showed that one of the Pro-hinged peptides, KL-L9P, displays the highest specificity toward E. coli. Moreover, KL-L9P sensitizes E. coli to be responsive to most antibiotics that are not active against Gram-negative bacteria. The results of biochemical experiments show that KL-L9P promotes the rearrangement of the bacterial membrane that enables hydrophobic antibiotics to permeate. Finally, the results of animal tests demonstrate that KL-L9P strongly sensitizes Gram-negative bacteria to linezolid (Lzd), rifampicin (Rif), or clarithromycin (Clr). Thus, KL-L9P operates as a sensitizer to extend the antibacterial activity of most antibiotics to Gram-negative bacteria.
Subject(s)
Anti-Bacterial Agents/pharmacology , Antimicrobial Cationic Peptides/pharmacology , Escherichia coli/drug effects , Animals , Anti-Bacterial Agents/chemistry , Antimicrobial Cationic Peptides/chemistry , Antimicrobial Cationic Peptides/metabolism , Cell Membrane/drug effects , Clarithromycin/pharmacology , Female , Hemolysis/drug effects , Humans , Hydrophobic and Hydrophilic Interactions , Linezolid/pharmacology , Lipid A/metabolism , Membrane Fluidity/drug effects , Mice, Inbred ICR , Microbial Sensitivity Tests , Proline/chemistry , Protein Binding , Protein Conformation, alpha-Helical , Rifampin/pharmacologyABSTRACT
In this study, we propose a reversible covalent conjugation method for peptides, proteins, and even live cells based on specific recognition between natural amino acid sequences. Two heptad sequences can specifically recognize each other and induce the formation of a disulfide bond between cysteine residues. We show the covalent bond formation and dissociation between peptides and proteins in cell-free conditions and on the surface of live cells. Because heptad sequences consist of natural amino acids, they are expressed in cells without additional preparation and can be used to selectively conjugate peptides, proteins, and cells.
