Natural and Synthetic Collagens as Cell Substrates for Biomedical Research

Abstract

Collagen is the most ubiquitous macromolecule found in mammals and is commonly used as a biomaterial in regenerative medicine therapies and biomedical research. It is typically derived from mammalian sources, such as bovine and porcine tissues, which poses sociological issues due to widespread religious constraints and ethical concerns over animal rights, as well as posing a continuous risk of zoonotic disease transmission. These issues have provided a strong incentive for research into alternative collagen sources, of which marine collagens have emerged as a promising resource. In particular, collagen derived from jellyfish has been frequently utilised to produce 3D biomaterials capable of culturing cells in vitro. While this is a promising development, the fundamental characteristics of these collagens have yet to be fully studied, and the question of whether collagen from a marine invertebrate is a comparable alternative to mammalian collagens is also unknown. Moreover, this raises the question of how does collagen benefit the application of cells in models and therapies, and can these mechanisms be reproduced without relying on animal-derived materials? The initial aim of this thesis was to characterise the collagen derived from the jellyfish Rhizostoma pulmo (JCol), and investigate how cells interact with this collagen in comparison to mammalian collagen. A key finding was that JCol did not facilitate cellular adhesion using the major collagen receptor alpha2beta1 integrin, but rather a combination of alpha1beta1 integrin and discoidin domain receptors 1/2. Following this, synthetic collagen peptides and recombinant collagens were developed for the purpose of studying specific cell-collagen interactions. The use of a alpha2beta1 integrin-specific collagen peptide as a substrate for the culture of mesenchymal stem cells (MSCs) was shown to upregulate the activation of intracellular signalling in response to transforming growth factor beta3 stimulation. This suggests that specific collagen interactions could be utilised to create biomaterials with an intrinsic capacity to induce phenotypic changes in cells. Finally, a hydrogel incorporating collagen peptides was developed as a 3D in vitro model. The differentiation of MSCs in 3D demonstrated a pro-osteogenic and pro-adipogenic effect when incorporating the alpha2beta1 integrin-specific collagen peptide, and this material was also developed as a bioink capable of being 3D bioprinted. This work highlights the potential for alternative collagens to be used as cell-instructive biomaterials in regenerative medicine applications.

Date of Award	17 Jan 2025
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Stephen Richardson (Supervisor), Jordi Bella (Supervisor) & Marco Domingos (Supervisor)