Enterochromaffin (EC) cells are the primary mechanosensors of the gastrointestinal (GI) epithelium. In response to mechanical stimuliEC cells release serotonin (5-hydroxytryptamine; 5-HT). The molecular details ofEC cell mechanosensitivity are poorly understood. Recently, our group found that human and mouseEC cells express the mechanosensitive ion channel Piezo2. The mechanosensitive currents in a humanEC cell model QGP-1 were blocked by the mechanosensitive channel blocker D-GsMTx4. In the present study we aimed to characterize the effects of the mechanosensitive ion channel inhibitor spider peptide D-GsMTx4 on the mechanically stimulated currents from both QGP-1 and human Piezo2 transfected HEK-293 cells. We found co-localization of 5-HT and Piezo2 in QGP-1 cells by immunohistochemistry. QGP-1 mechanosensitive currents had biophysical properties similar to dose-dependently Piezo2 and were inhibited by D-GsMTx4. In response to direct displacement of cell membranes, human Piezo2 transiently expressed in HEK-293 cells produced robust rapidly activating and inactivating inward currents. D-GsMTx4 reversibly and dose-dependently inhibited both the potency and efficacy of Piezo2 currents in response to mechanical force. Our data demonstrate an effective inhibition of Piezo2 mechanosensitive currents by the spider peptide D-GsMTx4.
Keywords: D-GsMTx4; Piezo2; enterochromaffin cell; mechanosensitive ion channel; mechanotransduction.