Confinement Sensing and Signal Optimization via Piezo1/PKA and Myosin II Pathways

Abstract

SUMMARYCells adopt distinct signaling pathways to optimize cell locomotion in different physical microenvironments. However, the underlying mechanism that enables cells to sense and respond to physical confinement is unknown. Using microfabricated devices and substrate-printing methods along with FRET-based biosensors, we report that, as cells transition from unconfined to confined spaces, intracellular Ca2+ level is increased, leading to phosphodiesterase 1 (PDE1)-dependent suppression of PKA activity. This Ca2+ elevation requires Piezo1, a stretch-activated cation channel. Moreover, differential regulation of PKA and cell stiffness in unconfined versus confined cells is abrogated by dual, but not individual, inhibition of Piezo1 and myosin II, indicating that these proteins can independently mediate confinement sensing. Signals activated by Piezo1 and myosin II in response to confinement both feed into a signaling circuit that optimizes cell motility. This study provides a mechanism by which confinement-induced signaling enables cells to sense and adapt to different physical microenvironments.

Cancer cell motility: lessons from migration in confined spaces

“…Physical cues, such as confinement, strongly influence tumour cell trafficking 19,46,47 . As confinement increases, it becomes more challenging for a cell to deform sufficiently so that it can squeeze into narrow spaces.…”

“…When the cross-sectional area of interfibrillar pores is less than ~7 μm 2 , matrix degradation is required for cancer cell migration to occur 18 , as discussed in detail below. Evidence suggests that confinement is a physical cue that modulates intracellular signalling 19 , thereby altering tumour cell migration mechanisms. This Opinion article discusses confined cancer cell motility, focusing on its in vivo relevance, migration mechanisms and confinement-induced cell responses.…”

How cells channel their stress: Interplay between Piezo1 and the cytoskeleton

“…These include cell indentation [2], membrane stretch [2], shear flow [23,24], substrate stiffness [25], substrate nanotopology [26], tissue compression [27], tissue distention [28], confinement [29], and osmotic stress [30]. The diverse nature of the activating stimuli naturally raises the question: what are the relevant physical and cellular parameters that gate the channel?…”

“…Hung et al found that Piezo1 is also involved in confined migration [29]. Cells are induced to migrate in confined spaces through bioengineered fibronectin-coated microchannels or along 8 um- wide 1D fibronectin-printed lines.…”

“…Highly metastatic breast cancer cells exhibit high Piezo1 expression, which has been correlated with worse outcomes in one patient population [63]. Metastatic breast cancer cells, invasive melanoma cells and gastric cancer cells exhibited reduced migration when Piezol was knocked down or pharmacologically inhibited [29,63,64]. In these cell types, higher Piezo1 activity has been proposed to underlie greater migration associated with the metastatic state.…”