Tuning RGD Motif and Hyaluronan Density to Study Integrin Binding

Abstract

Well-controlled surfaces with immobilized substrates enable novel approaches to investigate specific aspects of biological processes related to cell adhesion or motility. A subset of integrins, cellular transmembrane glycoproteins, recognize the evolutionarily conserved tripeptide sequence RGD, and anchor cells to their surrounding proteins as well as mediate bidirectional signaling. In this study, the main question was how co-presentation of hyaluronan (HA), an essential component of the extracellular matrix (ECM), and the RGD motif affect integrin binding. We report a method to prepare self-assembled monolayers on gold surfaces, co-presenting the cell adhesive RGD motif and small HA molecules, to investigate integrin containing proteoliposome binding. This technique enables an independent adjustment of the RGD motif and HA density while maintaining a passivating background: Layer formation and subsequent interactions with αIIbβ3 integrins, which are reconstituted in liposomes, was monitored by label-free quartz crystal microbalance with dissipation monitoring (QCM-D). Exceeding a critical RGD motif density of 40% results in enhanced binding of proteoliposomes. Co-presentation studies with varying HA and constant RGD motif density demonstrate that marginal amounts of HA are sufficient to prevent integrin binding. These findings are of specific importance in relation to cancer cell microenvironments, which show highly enriched HA in the surrounding ECM to reduce adhesion properties.

Aquaporin‐Incorporated Graphene‐Oxide Membrane for Pressurized Desalination with Superior Integrity Enabled by Molecular Recognition

“…The -RGD-sequence is known as a cell-binding peptide sequence, and the engineered vesicles incorporating the AQP proteins can have integrins that selectively bind to specific RGD peptides in the extracellular matrix. [21,22] -RGD-peptides tethered on the substrate can bind with the integrin of the vesicles, boost the AQP loading to the substrate, and enhance mechanical durability under high-pressure RO conditions. In this study, graphene oxide (GO) membranes were adopted as a substrate membrane because oxygen-containing functional groups on the GO surface can be easily modified with the desired peptides.…”

Anti-Tumor Activity and Pharmacokinetics of AP25-Fc Fusion Protein

“…Xu, H.M. et al found that ES-2 had good anti-angiogenetic activity in vitro , but its activity in vivo was moderated 28. In order for ES-2 to target tumor tissues, Xu and her colleagues designed AP25 by connecting RGD-4C (RGD-4C contains four cysteines, which form two disulfide bridges and confer the molecule higher stability 29,30) and ES-2. AP25 targets integrin αvβ3 and α5β1 on the surface of vascular endothelial cells and several animal experiments showed that it has significant anti-tumor effect 1-3.…”

A Review on the Enhancement of Calcium Phosphate Cement with Biological Materials in Bone Defect Healing

“…It is present in various proteins of the extracellular matrix, including fibronectin, vitronectin, and fibrinogen. This tripeptide motif has a strong affinity towards integrins, the transmembrane glycoproteins involved in anchoring cells to the extracellular matrix [ 32 ]. It is known that integrins are expressed in various types of cells including leukocytes [ 33 ], macrophages [ 34 ], endothelial cells [ 35 ], and bone cells [ 36 , 37 ].…”