A damaging COL6A3 variant alters the MIR31HG-regulated response of chondrocytes in neo-cartilage organoids to hyper-physiologic mechanical loading

Abstract

The pericellular matrix (PCM), with its hallmark proteins collagen type VI (COLVI) and fibronectin (FN), surrounds chondrocytes and is critical in transducing the biomechanical cues. To identify genetic variants that change protein function, exome sequencing is performed in a patient with symptomatic OA at multiple joint sites. A predicted damaging variant in COL6A3 is identified and introduced by CRISPR-Cas9 genome engineering in two established human induced pluripotent stem cell-derived in-vitro neo-cartilage organoid models. The downstream effects of the COL6A3 variant on the chondrocyte phenotypic state is studied by a multi-omics (mRNA and lncRNA) approach in interaction with hyper-physiological mechanical loading conditions. The damaging variant in COL6A3 resulted in significantly lower binding between the PCM proteins COLVI and FN and provoked an osteoarthritic chondrocyte state. By subsequently exposing the neo-cartilage organoids to hyper-physiological mechanical stress, we demonstrate that the COL6A3 variant in chondrocytes abolished the characteristic inflammatory signaling response after mechanical loading with PTGS2, PECAM1, and ADAMTS5, as central genes. Finally, by integrating epigenetic regulation, we identified the lncRNA MIR31HG as key regulator of the characteristic inflammatory signaling response to mechanical loading.

Full publication

The full publication can be found here.

Authors: Niek GC Bloks , Zainab Harissa, Giorgia Mazzini, Shaunak S Adkar, Amanda R Dicks, Ghazaleh Hajmousa, Nancy Steward, Roman I. Koning, Aat Mulder, Berend B.R. de Koning, Margreet Kloppenburg, Rodrigo Coutinho de Almeida, Yolande FM Ramos, Farshid Guilak, Ingrid Meulenbelt.