OC 68.1 - Discovery of piezo1 as a mediator of mechanotransduction in platelets

Tuesday, June 25, 2024

14:45 – 15:00 ICT

Room: 211 A-D

Co-Author(s)

As

Arif s/o Abdul Jabbar

Medical Student
Cambridge University
Cambridge, England, United Kingdom
SG

Suman Guntupalli

Technician
Cleveland Clinic
Cleveland, Ohio, United States
RB

Rohan Bhandari

Postdoctoral Fellow
Cleveland Clinic
Cleveland, Ohio, United States
AA

Anu Aggarwal

Postdoctoral Fellow
Cleveland Clinic
Cleveland, Ohio, United States
MG

Matthew Godwin

Graduate Student
Cleveland Clinic
Cleveland, Ohio, United States
MA

Mariya Ali

Research Technician
Cleveland Clinic
Cleveland, Ohio, United States
EP

Edelyn Huijun Park

Graduate Student
Cleveland Clinic
Cleveland, Ohio, United States
RS

Reina Samuel

Post-Baccalaureate Student
Cleveland Clinic
Cleveland, Ohio, United States

Presenting Author(s)

Scott J. Cameron, PhD, MD

Section Head, Vascular Medicine
Cleveland Clinic
Solon, Ohio, United States

Background: Biomechanical activation of platelets is poorly-understood, and occurs as blood passes through stenotic arteries or heart valves, and as blood traverses aneurysmal arteries. The role of piezo1, a well-known mechanotransducer, in platelets is unknown.

Aims: To determine the role of piezo1 in biomechanical and biochemical platelet activation.

Methods: Platelets were stained with FITC-anti-piezo1 antibody. Whole blood was incubated with piezo1 agonist Yoda1 and antagonist GsMTx-4 or vehicle. The rate of thrombus formation was measured with T-TAS system. Platelets exposed to biomechanical stress using flow cones to simulate disturbed flow (D-flow) and alpha-granule exocytosis quantified by surface P-selectin as mean fluoresce intensity (MFI) using fluorescence-assisted cell sorting (FACS). A platelet-specific piezo1-/- (knockout, KO) mouse was created to evaluate biomechanical platelet activation in vivo using topical elastase on the infrarenal aorta to create aortic aneurysms and expose platelets to D-flow circulation over several weeks (mechanical strain).

Results: Piezo1 was identified on the surface of human platelets. Incubation with 20μM Yoda1 or 10μM GsMTx-4 decreased (p=0.0489, n=7) and increased occlusion time (p=0.0317, n=4) respectively with the T-TAS. Yoda1 increased sensitized platelets to biomechanical platelet activation under D-flow while GsMTx-4 abolished this. Platelet piezo1-KO mice have a markedly open canalicular system and no difference in bleeding times compared to wild-type (WT) mice. In growing aortic aneurysms over 4 weeks, there was appearance of D-flow circulation with time-dependent activation in circulating platelets (WT week 0=23.8 vs. week 4=54.9, p< 0.001) that was diminished in platelet piezo1-KO mice (piezo1 KO=43.6 vs. 54.0 WT p=0.04, week 4) (Figure).

Conclusion(s): Piezo1 is a platelet mechanosensor that mediates activation without altering surface receptor agonist sensitivity. Platelet piezo1 diminishes biomechanical platelet activation in vivo without altering haemostasis. Further study is needed to determine the viability of platelet piezo1 as a therapeutic target to prevent biomechanical platelet activation.