Limited roles of Piezo mechanosensing channels in articular cartilage development and osteoarthritis progression

Area of Science:

• Biomedical Engineering
• Orthopedics
• Mechanobiology

Background:

• Osteoarthritis (OA) is a degenerative joint disease characterized by cartilage breakdown and pain.
• Piezo channels (Piezo1 and Piezo2) are known mechanotransducers involved in cellular responses to mechanical stimuli.
• The specific role of Piezo channels in the pathogenesis of OA remains largely unexplored.

Purpose of the Study:

• To investigate the functional role of Piezo1 and Piezo2 in the development of surgically induced osteoarthritis (OA) in a mouse model.
• To determine if the genetic ablation of Piezo1 and Piezo2 influences OA severity and associated pain.
• To examine the expression of OA-related genes in chondrocytes under fluid flow shear stress (FFSS) after Piezo channel deletion.

Main Methods:

• Generation of male conditional knockout (cKO) mice lacking Piezo1 and Piezo2 in the joint using Gdf5-Cre transgenic mice.
• Induction of post-traumatic OA via destabilization of the medial meniscus (DMM) surgery in 12-week-old mice.
• Histological assessment of OA severity, pain evaluation using static weight-bearing analysis, and in vitro FFSS experiments on isolated chondrocytes.

Main Results:

• Conditional deletion of Piezo1 and Piezo2 did not affect normal joint development or cause histological changes.
• DMM surgery induced moderate to severe OA in both control and cKO mice, with no significant difference in OA severity (OARSI scores).
• Piezo channel ablation did not provide protective effects against OA progression or reduce OA-associated pain; in vitro studies showed similar gene expression responses to FFSS in control and cKO chondrocytes.

Conclusions:

• Piezo1 and Piezo2 channels are not essential for normal joint development in mice.
• Genetic ablation of Piezo channels does not confer significant protection against surgically induced OA progression or pain.
• Mechanotransduction of fluid flow shear stress in OA pathogenesis may involve mechanotransducers other than Piezo channels.