Peptides liposomes

Torchilin VP, Levchenko TS, Rammohan R, et al. Cell transfection in vitro and in vivo with nontoxic TAT peptide-liposome-DNA complexes. Proc Natl Acad Sci USA 2003 100(4) 1972-1977. 

Tyr-Met, Trp-Met and Met-Met) have been studied by pulse radiolysis and steady-state y-radiolysis in aqueous and lipid vesicle suspensions. In Met-enkephalin, the attack of the H atoms occurs to -50% on Met with formation of methanethiyl radicals (CH3S ) (Scheme 10 peptide = Tyr-Gly-Gly-Phe-). The remaining percentage is divided roughly evenly between Tyr and Phe. The formation of diffusible CH3S derived from the reaction presented in Scheme 10 was monitored using tmns lipids as a biomarker in the peptide-liposome (l-palmitoyl-2-oleoyl phosphatidyl-choline (POPC) vesicles) system. The cis-tmns isomerization of phospholipids was detected due to the catalytic action of thiyl radicals vide supra. Scheme 1). 

Peptide liposome vaccines were prepared by freeze-thawing of the lipid/peptide mixtures followed by sequential filter extrusion. 

Griffiths, G.D., Phillips, G.J. and Bailey, S.C. (1999) Comparison of the quality of protection elicited by toxoid and peptide liposomal vaccine formulations against ricin as assessed by markers of inflammation. Vaccine, 17, 2562-2568. 

TAT-peptide or other CPP molecules attached to the liposome surface. Complexes of TAT-peptide-liposomes with a plasmid (plasmid pEGFP-Nl encoding for the Green Fluorescence Protein, GFP) were used for successful in vitro transfection of various tumor and normal cells as well as for in vivo transfection of tumor cells in mice bearing Lewis lung carcinoma. TAT-peptide liposomes have been also successfully used for transfection of intracranial tumor cell in mice via intracarotid injection ... 

Delivery of peptides and proteins via the gastrointestinal tract has not been successful because of poor penetration through the intestinal epithelium and high levels of proteolytic activity in the gastrointestinal tract. Liposomal encapsulation of proteins and peptides will not improve the efficiency and capacity of this absorption pathway considerably (e.g., Ryman et al., 1982 Machy and Leserman, 1987 Weiner and Chia-Ming Chiang, 1988). These difficulties in delivery via the oral route caused the parenteral route to remain the preferred route for the administration of therapeutic peptides... 

FIGURE 14 Pharmacokinetics of P-18-liposorae injected subcutaneously. Liposomes containing peptide hormone with... 

Yau-Yong, A., Chow, J., and Law, M. (1986). Liposome delivery of a biologically active peptide, 133rd Ann. Meeting Am. Pharm Assoc.. 16, 105. 

Using liposomes made from phospholipids as models of membrane barriers, Chakrabarti and Deamer [417] characterized the permeabilities of several amino acids and simple ions. Phosphate, sodium and potassium ions displayed effective permeabilities 0.1-1.0 x 10 12 cm/s. Hydrophilic amino acids permeated membranes with coefficients 5.1-5.7 x 10 12 cm/s. More lipophilic amino acids indicated values of 250 -10 x 10-12 cm/s. The investigators proposed that the extremely low permeability rates observed for the polar molecules must be controlled by bilayer fluctuations and transient defects, rather than normal partitioning behavior and Born energy barriers. More recently, similar magnitude values of permeabilities were measured for a series of enkephalin peptides [418]. 

Tumor tissues overexpress matrix metalloproteinases (MMPs). A liposomal pDNA carrier (MEND) was developed containing PEG conjugated to lipid via a peptide linker that is a target sequence for MMPs. In this strategy, PEG is removed from the carrier via MMP-triggered cleavage [198]. Intravenous administration in... 

Native chemical ligation also can be extended to the conjugation of peptides or proteins to other molecules or surfaces. For instance, Reulen et al. (2007) prepared liposomes that contained cysteine-PEG-phospholipid derivatives and then coupled thioester-modified peptides or proteins to form a protein-liposome conjugate. Using this procedure, approximately 100 molecules of a collagen binding protein could be coupled to the cysteine-containing liposomes. 

Figure 22.16 SMPB-activated liposomes may be modified with peptide hapten molecules containing cysteine thiol groups. The resultant immunogen may be used for immunization purposes to generate an antibody...

Protocol for the Coupling of Peptide Haptens Containing Sulfhydryl Groups to Liposomal Vesicles... 

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