Tandem Repeat of a Short Human Chemerin-Derived Peptide and Its Nontoxic d-Lysine-Containing Enantiomer Display Broad-Spectrum Antimicrobial and Antitubercular Activities

Abstract

To design novel antimicrobial peptides by utilizing the sequence of the human host defense protein, chemerin, a seven-residue amphipathic stretch located in the amino acid region, 109−115, was identified, which possesses the highest density of hydrophobic and positively charged residues. Although this 7-mer peptide was inactive toward microorganisms, its 14-mer tandem repeat (Chem-KVL) was highly active against different bacteria including methicillin-resistant Staphylococcus aureus, a multidrug-resistant Staphylococcus aureus strain, and slow-and fastgrowing mycobacterial species. The selective enantiomeric substitutions of its two L-lysine residues were attempted to confer cell selectivity and proteolytic stability to Chem-KVL. Chem-8dK with a D-lysine replacement in its middle (eighth position) showed the lowest hemolytic activity against human red blood cells among Chem-KVL analogues and maintained high antimicrobial properties. Chem-8dK showed in vivo efficacy against Pseudomonas aeruginosa infection in BALB/c mice and inhibited the development of resistance in this microorganism up to 30 serial passages and growth of intracellular mycobacteria in THP-1 cells.

Characterization of a Myeloid Differentiation Factor 2-Derived Peptide that Facilitates THP-1 Macrophage-Mediated Phagocytosis of Gram-Negative Bacteria

“…Selection of the Amino Acid Sequence, 54−69, for Opsonization and Phagocytosis Studies. It has been previously described that an MD54 peptide, LKGSKGLLHI-FYIPRR, comprising amino acid regions 54 to 69 of MD2, possesses a heptad repeat and its amino acid composition is conducive for interacting with LPS, the outer membrane component of Gram-negative bacteria MD54, 12,25 which induces aggregation of LPS and facilitates its internalization by human monocytic cells THP-1. Since the MD2 protein is known to opsonize and phagocytose Gram-negative bacteria, 10,11,26,27 we envisioned that it is worth exploring if this MD2-derived peptide MD54 (Table S1) could cause opsonization and phagocytosis of Gram-negative bacteria.…”

“…A model of bacteremia was established as described elsewhere. 25 4−6-week-old BALB/c mice were i.p. injected a 200 μL suspension (approximately 8 × 10 7 CFU/ml) of an E. coli (ATCC 25922) and P. aeruginosa (ATCC BAA-427) strain.…”

To Fold or Not to Fold: Diastereomeric Optimization of an α-Helical Antimicrobial Peptide

“…Membrane disruptive antimicrobial peptides (AMPs), which occur naturally as part of the innate immune system, offer an opportunity to address multidrug-resistant (MDR) bacteria because of their unspecific mechanism of action, against which resistance does not occur easily. − Such AMPs are however unstable in serum and most often toxic owing to their membrane disruptive amphiphilic and usually α-helical structure triggering their antibacterial effect. Their properties can be improved by sequence optimization, − whereby the most versatile approach consists in introducing non-natural structural elements such as d -amino acids, − non-natural residues, β- or γ-amino acids, , isopeptide bonds, or entirely non-peptidic elements such as spermine or fatty acids. , A complete redesign of AMPs is also possible in the form of dimers, cyclic or bicyclic staples, − small molecules, peptoids, , foldamers, or dendrimers. , …”

Regio- and Enantioselective Macrocyclization from Dynamic Imine Formation: Chemo- and Enantioselective Fluorescent Recognition of Lysine

“…Using fluorescent probes for the detection of amino acids has been extensively studied because fluorescence-based sensing provides advantages such as easily available instruments, high sensitivity, and real-time analysis . As an essential amino acid for humans, l -Lys is involved in processes such as proteinogenesis, uptake of mineral nutrients, and fatty acid metabolism. , d -Lys is found to be important in various bacteria and is also useful for the development of antimicrobial and antitubercular medicine . Although a variety of fluorescent probes have been developed for Lys analysis, , very few reports on chemoselective as well as enantioselective detection of Lys were reported before. , …”