Piezo1-Pannexin1 complex couples force detection to ATP secretion in cholangiocytes

Area of Science:

• Hepatology and Cell Biology
• Mechanobiology
• Biliary Physiology

Background:

• Cholangiocytes are crucial for bile secretion and are affected by mechanical stress in cholestasis.
• The precise mechanisms linking mechanical insults to cholangiocyte dysfunction remain unclear.

Purpose of the Study:

• To investigate the molecular mechanisms by which mechanical forces influence cholangiocyte function.
• To identify key proteins involved in mechanotransduction and ATP secretion in cholangiocytes.

Main Methods:

• Gene silencing and pharmacological inhibition in mouse cholangiocytes.
• Live calcium imaging to monitor cellular responses.
• Co-immunoprecipitation and pull-down assays to assess protein interactions.
• Reconstitution of the pathway in HEK cells.

Main Results:

• Piezo1 and Pannexin1 (Panx1) are essential for mediating the effects of mechanical stress.
• Piezo1 acts as a mechanosensor, translating cell swelling into Panx1 activation via intracellular calcium increase.
• Activated Panx1 triggers ATP release, which is amplified by P2X4R.
• Piezo1 and Panx1 form stable physical complexes at the plasma membrane.

Conclusions:

• Piezo1 and Panx1 form a functional signaling complex controlling force-induced ATP secretion in cholangiocytes.
• This Piezo1-Panx1-P2X4R pathway is critical for responding to mechanical stimuli.
• Findings provide a basis for developing new therapies for cholestatic liver diseases.