Peptides & Amino Acids

mouse Beta-Defensin 3 peptide (mBD3), a homolog of human beta-defensin 2 (hBD2), is a cysteine-rich cationic antimicrobial peptide of 41 amino acids which belongs to the defensins family. Defensin peptides are cationic peptides originally produced in various organs. They are involved in the protection against different kinds of pathogens like bacteria, fungi, and several viruses and play an important role in inflammation and wound repair. mBD3 peptide showed antimicrobial activity against Gram-negative bacteria S.Aureus and S.pyogenes and against Gram-positive bacteria like certain strains of P.Aeruginosa (MIC of 8 µg/mL) and E.coli (MIC of 16 µg/mL). Antimicrobial activity has also been demonstrated against C.Albicans. The in vivo and in vitro efficiency of mBD3 against viruses like influenza was also shown. mBD3 can be interesting for therapeutic use.

LL-37, also known as CAP-18 for Cathelicidin antimicrobial peptide 18, is a 37 amino acid cationic peptide. LL-37 is also a typical linear antimicrobial peptide which can eliminate a wide range of pathogenes, including bacteria, viruses, fungi, and parasites. LL-37 is the only human cathelicidin peptide reported yet, found in lysosomes of macrophages and leukocytes. LL-37 plays an important role in the first act of defense against local infection and systemic invasion of pathogens at sites of inflammation. LL-37 shows cytotoxicity against bacterial and normal eukaryotic cells and is significantly resistant to proteolytic degradation. Besides its antimicrobial functions, LL-37 also has immunomodulatory roles. LL-37 suppresses the production of pro-inflammatory cytokines, TNF-α and IL-6 in infected monocytes. LL-37 increases cytokine and chemokine liberation from local cells and leucocytes and has chemotactic effects on a large number of immune cells.

Hydrogels are a class of materials that are promising candidates for use in soft tissue and bone engineering. Hydrogels have a high water content, suitable viscoelasticity and biocompatibility. Using hydrogel can help for biomedical applications such as tissue engineering, encapsulation methods for cells and biomolecules, drug delivery or some injectable delivery vehicles for therapeutics. However, hydrogels are mainly used for their antimicrobial properties which are due to the surface of the hydrogel, having the capacity to disrupt negatively-charged bacterial membrane via electrostatic interactions. Antimicrobial activities of hydrogels were shown against gram-positive bacteria such as S.Aureus and gram-negative bacteria like E.Coli. The main interest of employing hydrogels is its biocompatibility in vitro and in vivo which permits to hydrogel to be able to perform an appropriate host response in a specific situation. It also seems that the antimicrobial peptide-based hydrogels are

RANTES (or Regulated upon Activation, Normal T-cell Expressed and Secreted), also known as CCL5 (Chemokine (CC chemokine ligand 5), is a protein classified as a chemotactic cytokine or chemokine. Chemokines are small soluble proteins that act as molecular signals to induce cellular migration during inflammation. RANTES is a member of the CC chemokine family and is involved in immunoregulatory and inflammatory processes. RANTES is expressed in a lot of immune cells and acts as a potent chemoattractant for T-cells, basophils, eosinophils, monocytes and other cell types by playing a major role in recruiting leukocytes into inflammatory sites and to activate them. RANTES also induces proliferation and activation of certain natural killer cells. RANTES synthesis is induced by TNF-alpha and IL-1 alpha, interacts with CCR3, CCR1 and CCR5 and activates some G-protein coupled receptors. Many of the biological activities of RANTES (Ca2+ influx, chemotactic response, basophil activation, T-cell s

Magainin-1 is a 23-amino acids peptide which belongs to the magainin peptide family. Magainins are antibiotic peptides with antibacterial, antiviral and antifungal activities. These peptides cause perturbation of membrane functions responsible for osmotic balance. Magainin-1 carries out its antibacterial activity by folding to an amphiphilic helix to interact specifically with lipidic bilayer, resulting in a permeability change. Magainin-1 has broad-spectrum, non-specific activity against a wide range of micro-organisms including viruses as HSV-1 and HSV-2, gram-positive and gram-negative bacteria, protozoa, yeasts and fungi. Magainin-1 may also be hemolytic and cytotoxic to cancer cells. Besides its antimicrobial activity, Magainin-1 presents an antifungal activity against some pathogens such as Candida Albicans with a antifungal activity of 4.15 uM. Recently, it has also been shown that magainin-1 can induce apoptosis of some leukemia cells at a concentration of 10 to 50 nM.

Mastoparan is a 14-residue cationic peptide toxin isolated from the wasp Vespula lewisii venom which shows an important potency as an antimicrobial and anticancer agent but also as a Cell Permeable Peptide. Mastoparan is mainly known to be a receptor-independant and allosteric regulator of G-protein by stimulating GTPase activity. Besides modulating the activity of G-protein, Mastoparan have the ability to bind other intracellular targets such as Ca2+-ATP (implicated in Ca2+ release), small GTP binding proteins rho and rac, and many others. Mastoparan also belongs to the cell permeable peptide (CPP) family. As such, Mastoparan increases the membrane conductance and permeability of planar lipid bilayer and liposomal membranes which leads to enhanced the penetration of Ca2+, Na+ or K+ ions. Mastoparan have also a potential antibiotic effect due to its potent antimicrobial activity which can turn Mastoparan to a potential drug for infectious diseases. Some studies have also reported that

Cecropin A is an antimicrobial peptide active against Gram-positive and Gram-negative bacteria. Some studies have suggested that cecropin A binds to negatively charged membrane lipids and form a packed layer which permeabilize the membranes and help to kill bacteria. It was shown that cecropin A presents a LC50 of 0.9 µM and a LC90 of 1.7 µM against certain E.Coli strains. Besides its well-known antimicrobial properties, studies have demonstrated tumoricidal activity of cecropin A against leukemia, lymphoma, colon carcinoma cell lines and other tumour cell lines. Furthermore, Cecropin A has a fungicidal activity. A study has shown that cecropin A reaches a complete lethality at approximately 25 mM for germinating conidia of Aspergillus spp. and a complete lethality for nongerminated and germinated conidia of Fusarium spp. at 1.5 mM.

Scrambled LL-37 has the same peptide sequence as LL-37 but loses helixforming property. Scrambled LL-37 can be used as a negative control of LL-37 studies.

CCL2 (Chemokine C-C Motif Ligand 2), also known as monocyte chemoattractant protein 1 (MCP1) or small inducible cytokine A2 (SCYA2), is a protein classified as a chemotactic cytokine or chemokine. CCL2 binds to the chemokine receptors CCR2 and CCR5. CCL2 belongs to the CC chemokine family, small soluble proteins whose main function is to regulate cell trafficking and that act as molecular signals to induce cellular migration during inflammation. Chemokines are secreted in response to signals such as proinflammatory cytokines and induce chemotaxis through the activation of G-protein-coupled receptors (GPCRs), which involves adhesion molecules and glycosaminoglycans. CCL2 is produced by a lot of cell types (endothelial, fibroblasts, epithelial, smooth muscle, monocytic, and microglial cells which are important for antiviral immune responses and in tissue), often after induction by oxidative stress, cytokines or growth factors. Unlike other chemokines such as RANTES, CCL2 exhibits a chemo