Materials composed of theDrosophila melanogasterprotein ultrabithorax are cytocompatible

Abstract

The Drosophila melanogaster Hox protein ultrabithorax (Ubx) has the interesting ability to hierarchically self-assemble in vitro into materials that have mechanical properties comparable to natural elastin. Ubx materials can be easily functionalized by gene fusion, generating potentially useful scaffolds for cell and tissue engineering. Here, we tested the cytocompatibility of fibers composed of Ubx or an mCherry-Ubx fusion protein. Fibers were cultured with three primary human cell lines derived from vasculature at low passage: umbilical vein endothelial cells, brain vascular pericytes, or aortic smooth muscle cells. No direct or indirect toxicity was observed for any cell line, in response to fibers composed of either plain Ubx or mCherry-Ubx. Cells readily adhered to Ubx fibers, and cells attached to fibers could be transferred between tissue cultures without loss of viability for at least 96 h. When attached to fibers, the morphology of the three cell lines differed somewhat, but all cells in contact with Ubx fibers exhibited a microtubular network aligned with the long axis of Ubx fibers. Thus, Ubx fibers are cytocompatible with cultured primary human vascular cells.

Materials composed of theDrosophilaHox protein Ultrabithorax are biocompatible and nonimmunogenic

“…We can generate Ubx fibers with mechanical properties comparable to natural elastin, and elastin is a major component of the extracellular matrix of vasculature . In addition, Ubx fibers are compatible with a variety of vascular cell types . These traits suggest Ubx materials may make useful vascular scaffolds.…”

“…Monomers of his‐tagged Ultrabithorax splicing isoform Ia were produced in E. coli from the pET19b‐UbxIa vector and purified as previously described . Ubx fibers were produced by the tray/buffer reservoir system, also as previously described …”

“…Ubx materials are compatible with a variety of cell types in vitro, including endothelial cells, smooth muscle cells, and pericytes. 16 Ubx materials do not leach toxins, and no signs of cytotoxicity were observed for cells in direct contact with fibers. Cells also readily attach to Ubx fibers, which are sufficient for their support.…”

“…Monomers of his-tagged Ultrabithorax splicing isoform Ia were produced in E. coli from the pET19b-UbxIa vector and purified as previously described. 16 Ubx fibers were produced by the tray/buffer reservoir system, also as previously described. 5,15,16 Immunogenecity studies in mice Preparation of sponges, fiber assembly and harvest were carried out inside a Level II Safety cabinet to maintain aseptic conditions.…”

“…However, these materials must also be biocompatible to be useful for tissue engineering. Ubx materials are compatible with a variety of cell types in vitro , including endothelial cells, smooth muscle cells, and pericytes . Ubx materials do not leach toxins, and no signs of cytotoxicity were observed for cells in direct contact with fibers.…”