Identification of peptides inhibiting adhesion of monocytes to the injured vascular endothelial cells through phage-displaying screening.
Using oxidized low-density lipoprotein (LDL)-injured vascular endothelial cells (ECs) as target cells, peptides specifically binding to the injured ECs were screened from a phage-displaying peptide library by using the whole-cell screening technique after three cycles of the adsorption-elution-amplification procedure. Positive phage clones were identified by ELISA, and the inserted amino acid sequences in the displaying peptides were deduced from confirmation with DNA sequencing. The adhesion rate of ECs to monocytes was evaluated by cell counting. The activity of endothelial nitric oxide synthase (eNOS), and the expression levels of caveolin-1 and intercellular adhesion molecule-1 (ICAM-1) were determined by Western blotting. Six positive clones specifically binding to injured ECV304 endothelial cells were selected from fourteen clones. Interestingly, four phages had peptides with tandem leucine, and two of these even shared an identical sequence. Functional analysis demonstrated that the YCPRYVRRKLENELLVL peptide shared by two clones inhibited the expression of ICAM-1, increased nitric oxide concentration in the culture media, and upregulated the expression of caveolin-1 and eNOS. As a result, the adhesion rate of monocytes to ECV304 cells was significantly reduced by 12.1%. These data suggest that the anti-adhesion effect of these novel peptides is related to the regulation of the caveolin-1/nitric oxide signal transduction pathway, and could be of use in potential therapeutic agents against certain cardiovascular diseases initiated by vascular endothelial cell damage.
Guo
Yu
Y
Institute of Pharmacy and Pharmacology, Nanhua University, Hengyang 421001, China.
Zhang
Jia
J
Wang
Ji-Cheng
JC
Yan
Feng-Xiang
FX
Zhu
Bing-Yang
BY
Huang
Hong-Lin
HL
Liao
Duan-Fang
DF
D000595:Amino Acid Sequence; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D007249:Inflammation / Q000276:immunology / Q000378:metabolism*; D008969:Molecular Sequence Data; D009000:Monocytes / Q000378:metabolism*; D019151:Peptide Library; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism*
D015815:Cell Adhesion Molecules; D019151:Peptide Library; D010455:Peptides