Mechanical stretch induces Ca(2+) influx and extracellular release of PGE(2) through Piezo1 activation in trabecular meshwork cells

The trabecular meshwork (TM) constitutes the main pathway for aqueous humor drainage and is exposed to complex intraocular pressure fluctuations. The mechanism of homeostasis in which TM senses changes in intraocular pressure and leads to normal levels of outflow resistance is not yet well understood. Previous reports have shown that Piezo1, a mechanically-activated cation channel, is expressed in TM and isolated TM cells. Therefore, we tested hypothesis that Piezo1 may function in response to membrane tension and stretch in TM. In human trabecular meshwork (hTM) cells, PIEZO1 was showed to be abundantly expressed, and Piezo1 agonist Yoda1 and mechanical stretch caused a Piezo1-dependent Ca(2+) influx and release of arachidonic acid and PGE(2). Treatment with Yoda1 or PGE(2) significantly inhibited hTM cell contraction. These results suggest that mechanical stretch stimuli in TM activates Piezo1 and subsequently regulates TM cell contraction by triggering Ca(2+) influx and release of arachidonic acid and PGE(2). Thus, Piezo1 could acts as a regulator of intraocular pressure (IOP) within the conventional outflow pathway and could be a novel therapeutic strategy to modulate IOP in glaucoma patients.