Figure 1.

Cartilage-Targeting IGF-1 Fusion Proteins Bind to Matrilin-3 and Cartilage Protein Lysate In Vitro

(A) Schematic diagram depicting the design of cartilage-targeting IGF-1 fusion proteins IGF1-c13, -c22, and -c26 and non-targeted IGF-1 (IGF1-NT). (B) To assess binding ability to matrillin-3 (Matn3), ELISA plates were coated with BSA and human or mouse Matn3, and they were incubated with different IGF-1 fusion proteins or a commercially available anti-Matn3 antibody (R&D Systems); binding was detected using an anti-Fc antibody (n = 6). (C) To assess binding specificity to cartilage, ELISA plates were coated with different tissue lysates, incubated with different IGF-1 fusion proteins, and detected with an anti-Fc antibody. All three cartilage-targeting IGF-1 fusion proteins (c13, c22, and c26) bound primarily to cartilage protein lysate and showed far less binding to lysates of other tissues (n = 6). Bar graph depicts mean ± SEM.