Elastin‐like polypeptides: A strategic fusion partner for biologics

Abstract

Elastin-like peptides (ELPs) are derivatives of tropoelastin with a unique property that allows them to stay soluble below a certain critical temperature but reversibly form aggregates above that temperature. Since they are derived from tropoelastin, ELPs are biocompatible, non-toxic, and non-immunogenic. The unique properties of ELPs have made them a desirable class of fusion tags used in several biomedical applications including targeted drug delivery and enhancing the half-life of protein drugs. The most significant property of an ELP is that when fused to other proteins, the phase transition property of the ELP is maintained, and the target protein can be purified using the thermally driven property of the ELP. The ELP tag purification process is simple and inexpensive, and involves cycling the protein above and below the transition temperature of the ELP fusion followed by centrifugation to obtain the desired protein, without any need for chromatography. Consequently, using ELPs as a purification tag should be potentially interesting to biopharmaceutical companies who spend a significant percentage of their manufacturing costs on expensive protein purification techniques such as chromatography and filtration. However, ELP tags have not yet been used for commercial protein purification due to some challenges of translating this technique, which has been demonstrated mostly in academic laboratories, to a biotechnology manufacturing environment. The article first reviews the state-of-the-art in protein "ELPylation," and discusses some applications which have benefitted from using ELP as a fusion tag. Then, the article discusses the main advantages of using ELP as a purification tag, and evaluates the remaining hurdles for its implementation in industrial protein production. Biotechnol. Bioeng. 2016;113: 1617-1627. © 2016 Wiley Periodicals, Inc.

Tissue scaffolds functionalized with therapeutic elastin‐like biopolymer particles

“…This characteristic thermal property of ELPs makes them suitable for various biomedical applications including regenerative medicine and tissue engineering, as particle formation can be achieved in situ at physiologically relevant temperatures allowing for sustained release of the fusion protein of interest. ELP particles have been shown to be nontoxic, to not induce an immune response and to provide excellent biocompatibility, presenting themselves as convenient biomaterials (Chilkoti, Christensen, & MacKay, 2006; Floss, Schallau, Rose‐John, Conrad, & Scheller, 2010; Yeboah, Cohen, Rabolli, Yarmush, & Berthiaume, 2016). Fusion of growth factors and other cytokines of interest to ELP chains at the genetic level can lead to therapeutic particles capable of sustained delivery of the therapeutic moiety.…”

Generation and immunogenicity assessment of ELPylated virus-like particles of porcine circovirus type 2

“…Like ELP, ELPylated proteins can be purified by inverse transition cycling (ITC) with the advantages of simplicity and low cost. Since they are derived from tropoelastin, ELP are biocompatible, non-toxic and non-immunogenic, making ELPylated proteins suitable for in vivo applications [12]. More recently, ELPylation has been used to improve the immunogenicity of influenza virus M protein [13] and hemagglutinin [14].…”

Modular Self‐Assembling Peptide Platform with a Tunable Thermoresponsiveness via a Single Amino Acid Substitution

“…The transition temperature depends on the identity of Xaa, the chain length (the number of VPGXG units), the peptide concentration, and the environmental ionic strength . To control T t within a temperature range applicable for biomedical purposes (25–43 °C), polypeptides that included tens or hundreds of VPGXG units were used in most previous studies . ELPs can be prepared by bacterial expression, chemical synthesis, or by the combination of both methods.…”

“…Because greater efforts and resources would be required as the structural and compositional complexities of the peptides increase, we here employed a facile synthetic method to screen ELPs with desired thermoresponsiveness. The inverse temperature phase transition can be described in two ways: massive coacervate formation following the development of “twisted filaments” by the lateral stacking of β‐spiral peptides or “micelle self‐assembly” when ELPs are amphiphilic . With regard to the latter mechanism, Pechar et al reported that miniaturized ELPs (four pentad repeats) can also be temperature responsive because of the aid of a small hydrophobic compound conjugated at their N‐terminus–a 9‐fluorenylmethoxycarbonyl (Fmoc) group .…”