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Systems biology reveals how altered TGFβ signalling with age reduces protection against pro-inflammatory stimuli

Lookup NU author(s): David Hodgson, Emeritus Professor Drew Rowan, Dr Carole Proctor



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Osteoarthritis (OA) is a degenerative condition caused by dysregulation of multiple molecular signalling pathways. Such dysregulation results in damage to cartilage, a smooth and protective tissue that enables low friction articulation of synovial joints. Matrix metalloproteinases (MMPs), especially MMP-13, are key enzymes in the cleavage of type II collagen which is a vital component for cartilage integrity. Transforming growth factor beta (TGFβ) can protect against pro-inflammatory cytokine-mediated MMP expression. With age there is a change in the ratio of two TGFβ type I receptors (Alk1/Alk5), a shift that results in TGFβ losing its protective role in cartilage homeostasis. Instead, TGFβ promotes cartilage degradation which correlates with the spontaneous development of OA in murine models. However, the mechanism by which TGFβ protects against pro-inflammatory responses and how this changes with age has not been extensively studied. As TGFβ signalling is complex, we used systems biology to combine experimental and computational outputs to examine how the system changes with age. Experiments showed that the repressive effect of TGFβ on chondrocytes treated with a pro-inflammatory stimulus required Alk5. Computational modelling revealed two independent mechanisms were needed to explain the crosstalk between TGFβ and pro-inflammatory signalling pathways. A novel meta-analysis of microarray data from OA patient tissue was used to create a Cytoscape network representative of human OA and revealed the importance of inflammation. Combining the modelled genes with the microarray network provided a global overview into the crosstalk between the different signalling pathways involved in OA development. Our results provide further insights into the mechanisms that cause TGFβ signalling to change from a protective to a detrimental pathway in cartilage with ageing. Moreover, such a systems biology approach may enable restoration of the protective role of TGFβ as a potential therapy to prevent age-related loss of cartilage and the development of OA.

Publication metadata

Author(s): Hodgson D, Rowan AD, Falciani F, Proctor CJ

Publication type: Article

Publication status: Published

Journal: PLoS computational biology

Year: 2019

Volume: 15

Issue: 1

Online publication date: 24/01/2019

Acceptance date: 26/11/2018

Date deposited: 14/02/2019

ISSN (print): 1553-734X

ISSN (electronic): 1553-7358

Publisher: PLoS


DOI: 10.1371/journal.pcbi.1006685

PubMed id: 30677026


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Funder referenceFunder name
MR/K006312/1Medical Research Council (MRC)
MR/K006312/1Medical Research Council (MRC)