Multivalency of Sonic Hedgehog Conjugated to Linear Polymer Chains Modulates Protein Potency

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• 作者：Samuel T. Wall ; Krishanu Saha ; Randolph S. Ashton ; Kimberly R. Kam ; David V. Schaffer ; Kevin E. Healy
• 刊名：Bioconjugate Chemistry
• 出版年：2008
• 出版时间：April 2008
• 年：2008
• 卷：19
• 期：4
• 页码：806 - 812
• 全文大小：857K
• 年卷期：v.19,no.4(April 2008)
• ISSN：1520-4812

文摘

A potently active multivalent form of the protein Sonic hedgehog (Shh) was produced by bioconjugation of a modified recombinant form of Shh to the linear polymers poly(acrylic acid) (pAAc) and hyaluronic acid (HyA) via a two-step reaction exploiting carboimiide and maleimide chemistry. Efficiency of the conjugation was ~75% even at stoichiometric ratios of 30 Shh molecules per linear HyA chain (i.e., 30:1 Shh/HyA). Bioactivity of the conjugates was tested via a cellular assay across a range of stoichiometric ratios of Shh molecules to HyA linear chains, which was varied from 0.6:1 Shh/HyA to 22:1 Shh/HyA. Results indicate that low conjugation ratios decrease Shh bioactivity and high ratios increase this activity beyond the potency of monomeric Shh, with approximately equal activity between monomeric soluble Shh and conjugated Shh at 7:1 Shh/HyA. In addition, high-ratio constructs increased angiogenesis determined by the in vivo chick chorioallantoic membrane (CAM) assay. These results are captured by a kinetic model of multiple interactions between the Shh/HyA conjugates and cell surface receptors resulting in higher cell signaling at lower bulk Shh concentrations.