Piezo is a family of mechanically gated ion channels important for a variety of pressure sensitive processes such as cardiovascular development and the sense of mechanical touch and pain. Current strategies attempting to address a diverse range of causes for pain and cardiovascular disorders are often accompanied with risks such as off-target effects and addiction. Understanding the sensory molecules that directly transduce physical force into signals in excitable cells will allow for the development of more accurately targeted therapies. Piezo channels are therefore promising candidates for such therapies. However, the specific structures involved in channel mechanosensitivity must be elucidated to drive the direction of drug development. The long-term goal of this project is to identify the domain(s) within Piezo that confer mechanosensitivity in order to establish a molecular understanding for pressure sensation and nociception. I hypothesize that within Piezo, specific domains are uniquely sensitive to mechanical force, whereas others are less sensitive in comparison. To test this hypothesis, I will apply a localized force on single domains of the ion channel and simultaneously measure modulations in channel activity with patch clamp electrophysiology. To accomplish this, I will conjugate paramagnetic nanobeads to predicted extracellular loops of Piezo and measure pressure-induced channel responses in the presence of a pulling force by a strong magnetic field. My preliminary data show that by using this approach I can detect shifts in mechanosensitivity that can be directly attributed to specific domains of the ion channel. This project will use a novel method to probe and identify the individual mechanosensor domain(s) in Piezo, providing specific molecular targets for chemical regulation of Piezo activity.
statement Piezo ion channels have a clear role in mechanosensation and pain as well as cardiovascular development. They exhibit enhanced activity with neuropathic pain, allodynia, and inflammation, and they are required for proper vascular physiology in both development and adulthood. As a mechanically activated ion channel, it is the first of its type to be identified in mammals and undoubtedly a promising target for regulation by small molecules. This proposal will establish a precise molecular target for such interventions by identifying the functional domain(s) through which Piezo senses mechanical force.
|Wu, Jason; Young, Michael; Lewis, Amanda H et al. (2017) Inactivation of Mechanically Activated Piezo1 Ion Channels Is Determined by the C-Terminal Extracellular Domain and the Inner Pore Helix. Cell Rep 21:2357-2366|
|Wu, Jason; Lewis, Amanda H; Grandl, Jörg (2017) Touch, Tension, and Transduction - The Function and Regulation of Piezo Ion Channels. Trends Biochem Sci 42:57-71|
|Wu, Jason; Goyal, Raman; Grandl, Jörg (2016) Localized force application reveals mechanically sensitive domains of Piezo1. Nat Commun 7:12939|