Investigating Purinergic Signalling in Chondrocytes

Saffer, Daniel (2024) Investigating Purinergic Signalling in Chondrocytes. Doctoral thesis, University of East Anglia.

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Abstract

Chondrocytes are the sole cell type in cartilage and are highly specialised to produce the cartilaginous extracellular matrix that gives rise to unique biochemical properties facilitating joint movement. This includes reducing friction on the articular surface, distributing load across the joint and in embryogenesis, forming the scaffold for bone synthesis. One of the most common disease states of the synovial joint is osteoarthritis (OA), of which the common pathophysiological finding is degraded and thinned cartilage. This deformation reduces its ability to maintain a functioning joint and leads to the pain and reduced mobility associated with OA. Purinergic signalling is the interaction between extracellular nucleotides and a host of nineteen receptors, dubbed purinergic receptors, which include seven ion channels (P2X1-7) and twelve GPCRs (G-protein coupled receptors) (A1, A2A, A2B, A3, P2Y1, P2Y2, P2Y4, P2Y6, P2Y11-14). Previous research has showed that purinergic signalling can influence key phenotypic changes in chondrocytes and bone cells, and that chondrocytes release nucleotides in response to certain stimuli.

The aim of the project was to establish a role for purinergic receptors in chondrocyte function, in health and disease. Analysis of existing datasets revealed that P2Y6 is upregulated in OA, which was confirmed experimentally. Primary human chondrocytes (PHC) had a UDP-elicited calcium response whilst two commonly used chondrocyte cell lines did not. Moreover, MRS2578, a specific P2Y6 antagonist, inhibited the chondrocyte’s ability to upregulate catabolic genes in response to interleukin 1-β, at both the mRNA and protein level. In addition, MRS2578 inhibited chondrogenesis in a murine cell line, ATDC5, at low concentrations by many outcomes. Furthermore, global RNAseq detected that UDP-βS, a stable P2Y6 agonist, reduced inflammatory cytokine expression by PHC, an effect that may be mediated by STAT6. As such, whilst there are many aspects of P2Y6 signalling in chondrocytes that remain unclear, a role for this receptor has been established in various aspects of chondrocyte physiology and may be pertinent in the effort to find better treatments for OA.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Biological Sciences
Depositing User:	Chris White
Date Deposited:	24 Mar 2025 11:17
Last Modified:	24 Mar 2025 11:17
URI:	https://ueaeprints.uea.ac.uk/id/eprint/98869
DOI:

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