Marcella van Hoolwerff | 06-09-2022 | Dissecting cellular function of fibronectin in osteoarthritic cartilage
The aim of this thesis was to combine transcriptomics, genetics and human disease modelling to obtain further insight into molecular processes underlying osteoarthritis. More specifically, we aimed to elucidate the role of long noncoding RNAs expression changes as aberrant epigenetic mechanism in regulating gene expression in chondrocytes. We identified previously unknown long noncoding RNAs associated with the osteoarthritic process and showed enrichment for cis¬-regulation of these long noncoding RNAs with target messenger RNAs.To provide insight in the etiology of osteoarthritis, causal pathways can be identified by unravelling the substantial genetic component. To this end, we investigated the biological functionality of the high-impact, pathogenic mutation identified in the gene fibronectin1 in an early-onset osteoarthritis family. We demonstrated that the identified causal missense mutation in the gelatin-binding domain of the extracellular matrix protein fibronectin resulted in significant decreased binding capacity to collagen type II.Finally, the common function of fibronectin1 was investigated in cartilage and what changes occur at the transcript level of fibronectin1 with osteoarthritis. Down-regulation of full-length fibronectin was unbeneficial for in vitro chondrogenesis, we hypothesize that this was caused by decreased availability of the classical integrin binding site of fibronectin.

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