Interrogating the Cellular and Molecular Mechanisms of Tissue Fibrosis

Abstract

Tissue fibrosis is a significant cause of morbidity worldwide. Pericytes, a type of mesenchymal progenitor cell, are closely associated with endothelial cells on blood vessels. Pericytes are increasingly recognised as a source of scar-forming myofibroblasts, which are key players in fibrosis due to their excessive deposition of extracellular matrix components. To explore the mechanisms driving the pericyte-to-myofibroblast transition, 2D cell cultures and 3D spheroids were stimulated with fibrosis-associated growth factors (TGF-β, PDGF-BB, EGF, VEGF, FGF2, CTGF), and the effects on cell viability, phenotype, and migration were assessed using PrestoBlue assays, immunofluorescent staining, and brightfield imaging. By comparing 2D mono- and co-culture models with 3D spheroids, context-dependent activation of the myofibroblast phenotype was revealed, with the most potent effects produced by TGF-β, followed by PDGF-BB. To better replicate tissue-like environments, gellan gum fluid gels with tuneable viscoelastic properties and micro-hollow fibres were fabricated and applied as 3D culture platforms. Furthermore, the effects of physiological stiffness in combination with TGF-β stimulation revealed cooperative effects on the expression of fibrosis-associated genes and proteins. Together, this work integrates biochemical, biophysical, and cellular interaction perspectives to provide a wide-ranging view of pericyte behaviour in fibrosis. By elucidating the mechanisms underlying the pericyte-to-myofibroblast transition, this thesis advances our understanding of fibrotic disease pathogenesis and highlights different biomaterial approaches as a promising platform for in vitro fibrosis modelling and therapeutic exploration.

Date of Award	Sept 2025
Original language	English
Awarding Institution	Aston University
Supervisor	Jill Johnson (Supervisor), Emma Louise Shepherd (Supervisor) & Patricia Perez-Esteban (Supervisor)