GsMTx4

Cell lines

HEK 293 cells

Preparation method

For Piezo1 channels, the extracellular solution contained 145 mM NaCl, 5 mM KCl, 3 mM MgCl2, 0.1 mM CaCl2, and 10 mM HEPES (pH 7.4). The pipette solution contained 133 mM CsCl, 10 mM HEPES (pH 7.4). The inhibition produced by application of GsMTx4 was followed by ∼60 s of washout, followed by application of WT GsMTx4 as a control.

Reaction Conditions

5 μM GsMTx4, 40s

Applications

GsMTx4 is a spider venom peptide that inhibits cationic mechanosensitive channels (MSCs). A model placing GsMTx4 at the membrane surface, where it is stabilized by the lysines, and occupying a small fraction of the surface area in unstressed membranes. When applied tension reduces lateral pressure in the lipids, the peptides penetrate deeper acting as “area reservoirs” leading to partial relaxation of the outer monolayer, thereby reducing the effective magnitude of stimulus acting on the MSC gate.

Animal models

Male C57BL/6 mice

Dosage form

To the WT and ClockΔ19/Δ19 mice, GsMTx4 or vehicle was administered via intraperitoneal injection (IP) at two different time-points, Z12- and ZT0-IP (higher and lower Piezo1 expression periods in the WT mice, respectively). The WT and ClockΔ19/Δ19 mice were injected with 0.75 (low dose-IP) or 1.5 mg/kg (high dose-IP) of GsMTx4 in 100 μL of distilled water.

Applications

VF decreased at ZT12-IP in WT mice only with high dose of GsMTx4 but showed no effects in ClockΔ19/Δ19 mice. GsMTx4 did not affect Uvol in both mice at ZT12-IP. A decrease in Uvol was observed in both mice at ZT0-IP; however, it was unrelated to GsMTx4-IP. The effects of GsMTx4 changed associated with the circadian clock and Piezo1 expression level.

References:

[1]. Gnanasambandam R, et al. GsMTx4: Mechanism of Inhibiting Mechanosensitive Ion Channels. Biophys J. 2017 Jan 10;112(1):31-45.

[2]. Ihara, Tatsuya, et al. "Different effects of GsMTx4 on nocturia associated with the circadian clock and Piezo1 expression in mice." Life Sciences 278 (2021): 119555.