Using BIOID Proximity Labelling to Characterise PDLIM5 Protein Interactome in Hepatic Stellate Cells

Jennings, Elliot (2025) Using BIOID Proximity Labelling to Characterise PDLIM5 Protein Interactome in Hepatic Stellate Cells. Masters by Research thesis (MPhil), Manchester Metropolitan University.

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Abstract

Metabolic Associated Fatty Liver Disease (MAFLD) is major burden for healthcare systems worldwide. Excess fat in ballooned hepatocytes, undergoes lipid peroxidation – causing local insult promoting the release of inflammatory cytokines. These activate Hepatic Stellate Cells (HSCs) and cause the production of extracellular matrix (ECM) proteins, which act to disrupt liver architecture, and stiffen the microenvironment. This stiffening of the microenvironment also has a profibrotic effect, mechanoactivating HSCs, which causes further damage to the organ. Over time, disruption progresses to cirrhosis, whereby functional cells are entrapped in scar tissue, signalling organ failure to be imminent. PDZ-LIM domain proteins (PDLIMs) are cytoskeletal adaptor proteins, which play key roles in signal transduction. Understanding the potential of PDLIMs to play major roles in HSC signal transduction, this project aims to: (1.) to characterise PDLIM5 expression in activated HSCs, and (2.) to use proximity-based labelling (BioID) in HSCs to characterise PDLIM5 interacting proteins. PDLIM5 expression was shown to increase during HSC activation, and BioID indicated that PDLIM5 interacted with a variety of proteins which participate in HSC activation. Investigations also found novel evidence of PDLIM2, PDLIM6, and PDLIM7 gene expression in HSCs, with PDLIM6 significantly upregulated in response to HSC activation. Investigations concluded that PDLIM5 likely participates in signal transduction in HSCs and determined, that more research must be performed to characterise PDLIMs interactomes in HSCs.