16.1.5 - Mitochondrial Transport Between Chondrocytes and Mesenchymal Stromal Cells
- J. Korpershoek (Utrecht, NL)
- J. Korpershoek (Utrecht, NL)
- M. Rikkers (Utrecht, NL)
- F. Wallis (Utrecht, NL)
- K. Dijkstra (Utrecht, NL)
- D. Saris (Rochester, US)
- L. Vonk (Teltow, DE)
Abstract
Purpose
IMPACT is a one-stage cartilage transplantation for large cartilage defects, in which 10% autologous chondrons are combined with 90% donor mesenchymal stromal cells (MSCs). One year after transplantation, the regenerated cartilage does not contain donor autosomal DNA. This indicates that the MSCs do not differentiate, but act as signalling cells. The aim of this study is to investigate whether transport of mitochondria exists between chondrocytes and MSC and to investigate if the transfer of mitochondria to chondrocytes contributes to the mechanism of action of MSCs.
Methods and Materials
Chondrocytes were isolated from cartilage defect rims during autologous chondrocyte implantation. MSCs were isolated from surplus bone marrow donated for transplantation. Mitochondria were stained with mitotracker and cell trace was used to distinguish between cell types. After 4 to 24 hours of co-culture, the uptake of fluorescent mitochondria was measured using flow cytometry. Transport was visualized using fluorescence microscopy. Mitochondria were isolated from MSCs and transferred to chondrocytes using MitoCeption. Pellets of 100.000 chondrocytes, chondrocytes with transferred MSC mitochondria, and co-cultures (chondrocyte:MSC; 10:90) were cultured for 28 days. DNA content was measured using qubit fluorometric quantification and proteoglycan content using a Dimethylmethylene Blue Assay.
Results
Mitochondrial transport takes place bidirectional in co-cultures of chondrocytes and MSCs and chondrocytes monocultures and reaches a maximum at 16 hours (Figure 1). Mitochondria are transported via tunnelling nanotubes and direct cell-contact. DNA content and proteoglycan deposition are higher in chondrocyte pellets with transferred MSC mitochondria compared to chondrocyte pellets (Figure 2).
Conclusion
We demonstrate and quantify the transport of mitochondria between MSCs and chondrocytes for the first time. We show the positive effect of uptake of mitochondria by chondrocytes on DNA content and proteoglycan deposition. Further insight into the causes and results of mitochondrial transfer between MSCs and chondrocytes could improve the selection of MSCs and increase the effectivity of regenerative therapies.