Single mechanosensitive and Ca²⁺-sensitive channel currents recorded from mouse and human embryonic stem cells

Area of Science:

• * Stem cell biology
• * Electrophysiology
• * Ion channel function

Background:

• * Embryonic stem cells (ESCs) possess unique properties for growth and differentiation.
• * Understanding ion channel expression in ESCs is crucial for regenerative medicine.
• * Differential ion channel expression may explain species-specific ESC behaviors.

Purpose of the Study:

• * To compare the functional expression of ion channels in mouse ESCs (mESCs) and human ESCs (hESCs).
• * To investigate the role of mechanosensitive and Ca2+-sensitive channels in ESCs.
• * To correlate ion channel expression with species-specific ESC characteristics.

Main Methods:

• * Cell-attached and inside-out patch clamp electrophysiology.
• * Functional characterization of ion channel activity in mESCs and hESCs.
• * Quantitative analysis of channel densities in patched membranes.

Main Results:

• * Both mESCs and hESCs express mechanosensitive Ca2+ permeant cation (MscCa) channels and large conductance Ca2+-sensitive K+ (BK(Ca2+)) channels.
• * MscCa channels are more abundant in mESCs (70% of patches) than hESCs (3%).
• * BK(Ca2+) channels are more abundant in hESCs (~50% of patches) than mESCs (~1%).
• * A distinct 25 pS nonselective cation channel, activated by patch formation, was observed in both species.

Conclusions:

• * Significant differences exist in the expression levels of MscCa and BK(Ca2+) channels between mESCs and hESCs.
• * These differential channel expressions may influence how ESCs respond to mechanical and chemical stimuli.
• * Findings suggest a basis for distinct growth and differentiation patterns observed in mouse and human ESCs.