Cooperative modulation of PIEZO1 channels

This project addresses fundamental questions about how mammalian Piezo1 mechanosensitive ion channels are activated by mechanical force and by a synthetic chemical agonist, Yoda1. Piezo1 channels are cation-selective membrane proteins that transduce mechanical stimuli into electrical and biochemical signals, performing essential roles in processes such as red blood cell volume regulation, somatic and visceral mechanosensation, proprioception, blood pressure control, and tissue development and differentiation. Mutations in Piezo channels are linked to human diseases including xerocytosis and lymphedema, and Piezo-mediated signaling has been implicated in pain sensitization and possibly in conditions such as sleep apnea. Because of their central physiological roles and disease associations, Piezo channels are promising therapeutic targets, but the molecular mechanisms underlying their mechanical gating and chemical modulation remain poorly understood.

Lacroix and colleagues propose a multidisciplinary program combining molecular dynamics (MD) simulations and experimental assays to capture Piezo1 structural dynamics across wide temporal scales and to define how mechanical force and Yoda1 binding alter channel conformation and energetics. The first aim focuses on identifying rapid, force-induced structural rearrangements by simulating the Piezo1 molecule embedded in a lipid membrane under tension. Complementing these computational approaches, the team will apply force-clamp fluorimetry to probe local conformational changes in real time. This experimental method involves inserting spectroscopic conformational probes at strategic positions within the expressed channel protein while simultaneously monitoring function, enabling direct correlation of structural changes with channel activity. By integrating high-resolution MD simulations with temporally resolved spectroscopic readouts, the project seeks to bridge microsecond-scale molecular events and slower functional transitions, providing a dynamic view of how membrane tension is transduced into pore opening.

The second aim tackles the chemical activation of Piezo1 by Yoda1. Building on prior identification of a Yoda1 binding site through predictive MD simulations and experimental validation, Lacroix’s team will characterize the structural rearrangements, shifts in transition free energy, and alterations in allosteric residue-residue interactions that occur upon Yoda1 binding. These studies are designed to illuminate how a small molecule agonist stabilizes or promotes channel states conducive to opening, thereby revealing the allosteric pathways connecting ligand binding to channel gating. Detailed thermodynamic and structural mapping of Yoda1-induced changes will not only clarify the mechanism of chemical activation but also inform rational design of pharmacological agents that selectively modulate Piezo1 activity.

Overall, this research integrates computational modeling and precise experimental biophysics to define the mechanochemical principles governing Piezo1 gating. By elucidating how mechanical force and a chemical agonist cooperatively modulate Piezo1 structure and energetics, Lacroix’s work aims to provide foundational knowledge that could enable development of targeted therapeutics for Piezo-related pathologies and broaden the pharmacological toolkit for modulating mechanotransduction.