Mechanosensitive ion channels rely on membrane composition to transduce physical stimuli into electrical signals. Piezo channels mediate mechanoelectrical transduction to regulate crucial physiological processes, including vascular architecture and remodeling, cell migration, erythrocyte volume, touch, vibration, and proprioception. Piezo1 and Piezo2 are essential proteins in mice, as global knockouts are embryonic lethal and cell-specific knockouts result in animals with severe defects. In humans, Piezo channels gain- and loss-of-function mutations have been associated with hereditary human pathophysiologies. Mutations in Piezo1 are associated with dehydrated hereditary stomatocytosis, a hemolytic anemia characterized by increased cation permeability and dehydrated erythrocytes. Hence, it is essential to determine the proteins and lipids that regulate Piezo channels gating mechanisms. It has been shown that phosphoinositides and phosphatidylserine translocation regulate Piezo channels activity. However, it remains largely unknown how dietary fatty acids-containing phospholipids modulate Piezo1 and Piezo2 mechanical gating. Our long-term goal is to determine the mechanisms underpinning how bioactive lipids modulate mechanosensitive ion channels. In this proposal, the overall objective is to establish the molecular basis underlying Piezo channels modulation by dietary fatty acids. The central hypothesis is that Piezo channels activation and inactivation are regulated by the mechanical properties of the membrane via lipid remodeling. The rationale for the proposed research plan is that once the precise mechanisms are determined whereby fatty acids modulate Piezo channels function, it will be possible to use fatty acids to control vascular function and ameliorate the effects of hereditary disorders. The hypothesis will be tested by pursuing three Specific Aims: 1) Determine how fatty acid composition modulates Piezo1 activity through changes in membrane stiffness; 2) Determine the effect of dietary fatty acids on Piezo1 mutations causing red blood cell disorders; and 3) Test the hypothesis that saturated fatty acids decrease Piezo2 activation. We will leverage functional, biochemical, and biophysical approaches to uncover the contribution of bioactive lipids to mechanosensation. The research plan is innovative because it exploits the use of dietary fatty acids to control Piezo channels mechanical response. The proposed research is significant because it is expected to have broad translational impact in targeting Piezo channels, involved in vascular and neuronal function.
Piezo channels translate mechanical stimuli into electrical signals to regulate physiological processes such as blood pressure, red blood cell volume regulation, and touch sensation; Piezo mutations have been associated with several hereditary human diseases including hemolytic anemia and ataxia. The proposed study is relevant to NIH?s mission because it demonstrate how fatty acids modulate the mechanical response of Piezo channels. The proposed research is relevant to public health because combining dietary fatty acids might be a new strategy to abrogate the phenotypes of a Piezo mutant causing hemolytic anemia.
