Rhamnose Binding Protein as an Anti-Bacterial Agent-Targeting Biofilm of Pseudomonas aeruginosa.

More than 80% of infectious bacteria form biofilm, which is a bacterial cell community surrounded by secreted polysaccharides, proteins and glycolipids. Such bacterial superstructure increases resistance to antimicrobials and host defenses. Thus, to control these biofilm-forming pathogenic bacteria requires antimicrobial agents with novel mechanisms or properties. Pseudomonas aeruginosa, a Gram-negative opportunistic nosocomial pathogen, is a model strain to study biofilm development and correlation between biofilm formation and infection. In this study, a recombinant hemolymph plasma lectin (rHPLOE) cloned from Taiwanese Tachypleus tridentatus was expressed in an Escherichia coli system. This rHPLOE was shown to have the following properties: (1) Binding to P. aeruginosa PA14 biofilm through a unique molecular interaction with rhamnose-containing moieties on bacteria, leading to reduction of extracellular di-rhamnolipid (a biofilm regulator); (2) decreasing downstream quorum sensing factors, and inhibiting biofilm formation; (3) dispersing the mature biofilm of P. aeruginosa PA14 to improve the efficacies of antibiotics; (4) reducing P. aeruginosa PA14 cytotoxicity to human lung epithelial cells in vitro and (5) inhibiting P. aeruginosa PA14 infection of zebrafish embryos in vivo. Taken together, rHPLOE serves as an anti-biofilm agent with a novel mechanism of recognizing rhamnose moieties in lipopolysaccharides, di-rhamnolipid and structural polysaccharides (Psl) in biofilms. Thus rHPLOE links glycan-recognition to novel anti-biofilm strategies against pathogenic bacteria.

Synthesis of α-1,2- and α-1,3-linked di-rhamnolipids for biological studies.

For a detailed examination of the interaction of rhamnose containing derivatives with recombinant horseshoe crab plasma lectin (rHPL), two di-rhamno-di-lipids (an α-1,2- and an α-1,3-linked) were synthesized via a new simple method. The N-iodosuccinimide/triflic acid mediated glycosylation of the methyl (R)-3-hydroxydecanoate with phenyl-1-thio-rhamnobioside donors afforded the mono-lipid disaccharides. Removal of the methyl ester group followed by esterification of the mono-lipids with a second (R)-3-hydroxydecanoate unit resulted in fully protected di-lipid derivatives, transformation of which into the target compounds was accomplished in two steps. This method allows the synthesis of both regioisomers in only 6 steps starting from the corresponding free disaccharides. Both synthetic di-rhamnolipids were biologically active for lectin binding differential binding preference between two isomeric di-rhamno-di-lipids. The rHPL lectin favours the α-1,3-linked di-rhamno-di-lipids over its α-1,2-linked regioisomer.

Cell Penetrating Peptide as a High Safety Anti-Inflammation Ingredient for Cosmetic Applications.

Cosmeceutical peptides have become an important topic in recent decades in both academic and industrial fields. Many natural or synthetic peptides with different biological functions including anti-ageing, anti-oxidation, anti-infection and anti-pigmentation have been developed and commercialized. Current cosmeceutical peptides have already satisfied most market demand, remaining: "cargos carrying skin penetrating peptide with high safety" still an un-met need. To this aim, a cell-penetrating peptide, CPPAIF, which efficiently transported cargos into epithelial cells was exanimated. CPPAIF was evaluated with cell model and 3D skin model following OECD guidelines without using animal models. As a highly stable peptide, CPPAIF neither irritated nor sensitized skin, also did not disrupt skin barrier. In addition, such high safety peptide had anti-inflammation activity without allergic effect. Moreover, cargo carrying activity of CPPAIF was assayed using HaCaT cell model and rapid CPPAIF penetration was observed within 30 min. Finally, CPPAIF possessed transepidermal activity in water in oil formulation without disruption of skin barrier. All evidences indicated that CPPAIF was an ideal choice for skin penetrating and its anti-inflammatory activity could improve skin condition, which made CPPAIF suitable and attractive for novel cosmeceutical product development.