TRPC1 links calcium signaling to cellular senescence in the protection against post-traumatic osteoarthritis.

Transient receptor potential channel 1 (TRPC1) is a widely expressed mechanosensitive ion channel located within the endoplasmic reticulum membrane, crucial for refilling depleted internal calcium stores during activation of calcium-dependent signaling pathways. Here, we demonstrate that TRPC1 activity is protective within cartilage homeostasis in the prevention of cellular senescence associated cartilage breakdown during mechanical and inflammatory challenge. We reveal that TRPC1 loss is associated with early stages of osteoarthritis (OA) and plays a non-redundant role in calcium signaling in chondrocytes. Trpc1-/- mice subjected to destabilization of the medial meniscus induced OA developed a more severe OA phenotype than wild type controls. During early OA development, Trpc1-/- mice displayed an increased chondrocyte survival rate, however remaining cells displayed features of senescence including p16INK4a expression and decreased Sox9. RNA sequencing identified differentially expressed genes related to cell number, apoptosis and extracellular matrix organization. Trpc1-/-chondrocytes exhibited accelerated dedifferentiation, while demonstrating an increased susceptibility to cellular senescence. Targeting the mechanism of Trpc1 activation may be a promising therapeutic strategy in osteoarthritis prevention.