Piezo1-induced durotaxis of pancreatic stellate cells depends on TRPC1 and TRPV4 channels.

UNLABELLED: Here, we examine the impact of mechanosensitive ion channels on the durotaxis of pancreatic stellate cells (PSCs). PSCs are primarily responsible for producing the stiff tumor tissue in pancreatic ductal adenocarcinoma (PDAC). Thereby, PSCs generate a stiffness gradient between the healthy pancreas and the tumor. This gradient induces durotaxis, a form of directional cell migration driven by differential stiffness. The molecular sensors behind durotaxis are still unclear. To investigate the role of mechanosensitive ion channels in PSC durotaxis, we established a two-dimensional linear stiffness gradient mimicking PDAC. Using pharmacological and genetic methods, we investigated the role of the ion channels Piezo1, TRPC1, and TRPV4 in durotaxis of primary murine PSCs. We found that PSCs migrate towards a stiffer substrate, which is abolished by clamping Piezo1 activity to zero (knockout) or to its maximal value (Piezo1 activator Yoda1). Hence, PSC durotaxis is optimal with an intermediary, dynamically changing level of Piezo1 channel activity. Based on these findings we developed and numerically discretized a mathematical model of partial differential equations to simulate PSC durotaxis, raising the possibility that PSC accumulation during PDAC progression is partly due to durotaxis. We extended our biological model to TRPV4 and TRPC1, key sensors, and signal transducers for mechanical forces in PSCs. Disrupting TRPC1 along with TRPV4 abolishes PSC durotaxis even when Piezo1 is functional. These findings suggest that mechanosensitive ion channels, particularly Piezo1, detect the mechanical microenvironment to guide PSC migration. Yet, Piezo1 relies on TRPC1 and TRPV4 to orchestrate durotaxis.

SIGNIFICANCE STATEMENT: Cells, located on a substrate of differential stiffness, move toward regions with higher stiffness in a process called durotaxis. The exact mechanisms of sensing the changes in environmental stiffness during durotaxis are unclear. This study shows that mechanosensitive ion channels are crucial sensors in pancreatic stellate cell durotaxis. Key ion channels involved in sensing and transducing mechanical cues in these cells include Piezo1, TRPV4, and TRPC1. We found that these ion channels need to be in an intermediary active state to guide durotaxis. This helps to understand pancreatic cancer pathophysiology better and highlights mechanosensitive ion channels as targets to affect durotaxis.