18.2.10 - Mechano-ion-channel activation of TRPV4 promotes cartilage differentiation of MSCs and chondroprogenitors
- A. El Haj (Birmingham, GB)
- A. El Haj (Birmingham, GB)
- I. Echevarria (Bimringham, GB)
- H. Markides (Birmingham, GB)
Abstract
Purpose
The absence of a long term treatment for OA has led to the development of new approaches for early intervention. Mechanical regulators, such as TRPV4, play a key role in OA and are potential targets for early treatments. We demonstrate a new technology to remotely mechano-activate ion channels such as TRPV4 to control MSc and chondrogenic differentiation and maturation.
Methods and Materials
MScs from bone marrow and other sources cultured as pellets (4x105 cells) and micromass cultures (5x104 cells). In some cases, cells were previously transfected with GFP- collagen type 2 reporters. Cells were labelled with Nanomag (250 nm) with carboxylic coating and linked to the specific antibody for each group: TRPV4 and RGD. Cells were cultured for 21 days in chondrogenic, chondrogenic without TGF-B3 and basal media.The tagged cells were submitted to a 1h daily cyclical magnetic field controlled by a MICA bioreactor (MICA Biosystems Ltd) or static. Chondrogenic differentiation was monitored with temporal key markers.
Results
In response to the mechano-activation of TRPV4, we observed an increase in Collagen 2 and enhanced early expression onset in transfected MSCs at 14 days in culture. Histological and molecular analysis demonstrated a similar pattern for Collagen 2 and aggrecan up-regulation in MSCs. Enlarged pellet size was observed in the TRPV4 tagged chondroprogenitors compared to controls with an increase in uniform expression patterns (Figure 1). Elevated proliferation levels were found in the activated ion channel group. Further work underway includes ex vivo models to demonstrate remote control.
Conclusion
The development of allogeneic injectable solutions for early OA therapy could provide solutions which would improve long lasting motility with ageing. MICA approaches using MNPs tagged to receptor targets has the potential to generate these new therapies. The use of ion channels such as TRPV4 as targets for enhancing chondrogenesis is being explored further in ex vivo and animal models.