Identification of chondrocyte-binding peptides by phage display

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SAT 632-648-Pediatric Growth Case Reports
Basic
Saturday, June 15, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SAT-645
Crystal Cheung*1, Julian Lui2 and Jeffrey Baron3
1National Institute of Health, Bethesda, MD, 2NICHD, Bethesda, MD, 3NIH, Bethesda, MD
Growth plate cartilage disorders can impair bone growth and cause bone deformity. As a first step toward novel experimental and therapeutic approaches to these disorders, we used phage display to identify peptides that bind cartilage tissue. An M13 phage library that displayed random 12-amino acid peptides on the viral surface was iteratively selected for binding to cultured primary murine chondrocytes. 23 resulting phage clones were then picked and assessed for their binding characteristics by ELISA. Of these clones, 8 showed at least a 2-fold increase in binding to cultured chondrocytes, compared to a phage lacking the inserted peptide. Phage clones C1 and C19, which display peptide sequences RLDPTSYLRTFW and HDSQLEALIKFM respectively, exhibited the greatest binding to cultured chondrocytes. Using ELISA, these two phage were also demonstrated to have substantially less affinity to fibroblasts, myocytes, osteoblasts and hepatocytes, compared to chondrocytes, suggesting an interaction that was moderately tissue-specific. Immunohistochemical staining revealed that phage C1 and C19 bound both to cultured chondrocytes and to their surrounding extracellular matrix . To confirm that the binding to chondrocytes and matrix was attributable to the affinity of the inserted peptide independent of the phage coat proteins, free peptides, conjugated with the fluorescent probe FITC, were synthesized and incubated with cultured chondrocytes. Peptides C1 and C19 but not a random peptide bound to both cultured chondrocytes and extracellular matrix, confirming that binding involved the peptides per se. In conclusion, peptide sequences that target chondrocytes were identified by phage display, suggesting that this approach has the potential to identify molecules with high affinity and specificity for cartilage.

Nothing to Disclose: CC, JL, JB

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: This work was supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health.