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Piezo1 is a Ca2+‐permeable mechanically activated ion channel that is involved in various physiological processes and cellular responses to mechanical stimuli. The study of biophysical characteristics of Piezo1 is important for understanding the mechanisms of its function and regulation. Stretch activation, a routine approach that is applied to stimulate Piezo1 activity in the plasma membrane, has a number of significant limitations that complicate precise single‐channel analysis. Here, we aimed to determine pore properties of native Piezo1, specifically to examine permeation for physiologically relevant signaling divalent ions (calcium and magnesium) in human myeloid leukemia K562 cells using Piezo1‐specific chemical agonist, Yoda1. Using a combination of low‐noise single‐current patch‐clamp recordings of Piezo1 activity in response to Yoda1, we have determined single‐channel characteristics of native Piezo1 under various ionic conditions. Whole‐cell assay allowed us to directly measure Piezo1 single currents carried by Ca2+ or Mg2+ ions in the absence of other permeable cations in the extracellular solutions; unitary conductance values estimated at various concentrations of Mg2+ revealed strong saturation effect. Patch clamp data complemented with fluorescent imaging clearly evidenced Ca2+ and Mg2+ entry via native Piezo1 channel in human leukemia K562 cells. Mg2+ influx via Piezo1 was detected under quasi‐physiological conditions, thus showing that Piezo1 channels could potentially provide the physiological relevant pathway for Mg2+ ion transport and contribute to the regulation of Mg2+‐dependent intracellular signaling. [ABSTRACT FROM AUTHOR]

Endometrial mesenchymal stem cells (eMSCs) are a specific class of stromal cells which have the capability to migrate, develop and differentiate into different types of cells such as adipocytes, osteocytes or chondrocytes. It is this unique plasticity that makes the eMSCs significant for cellular therapy and regenerative medicine. Stem cells choose their way of development by analyzing the extracellular and intracellular signals generated by a mechanical force from the microenvironment. Mechanosensitive channels are part of the cellular toolkit that feels the mechanical environment and can transduce mechanical stimuli to intracellular signaling pathways. Here, we identify previously recorded, mechanosensitive (MS), stretch-activated channels as Piezo1 proteins in the plasma membrane of eMSCs. Piezo1 activity triggered by the channel agonist Yoda1 elicits influx of Ca2+, a known modulator of cytoskeleton reorganization and cell motility. We found that store-operated Ca2+ entry (SOCE) formed by Ca2+-selective channel ORAI1 and Ca2+ sensors STIM1/STIM2 contributes to Piezo1-induced Ca2+ influx in eMSCs. Particularly, the Yoda1-induced increase in intracellular Ca2+ ([Ca2+]i) is partially abolished by 2-APB, a well-known inhibitor of SOCE. Flow cytometry analysis and wound healing assay showed that long-term activation of Piezo1 or SOCE does not have a cytotoxic effect on eMSCs but suppresses their migratory capacity and the rate of cell proliferation. We propose that the Piezo1 and SOCE are both important determinants in [Ca2+]i regulation, which critically affects the migratory activity of eMSCs and, therefore, could influence the regenerative potential of these cells. [ABSTRACT FROM AUTHOR]

The potassium channels are one of the key regulators of cell membrane potential and permeability properties of blood cells. The changes in functioning of potassium channels control crucial cell processes such as proliferation, viability, migration, and invasion. The correct estimation of these processes is important for the characterization of physiological and pathophysiological cell states. Here, we present the experimental protocol for evaluation of the role of potassium ion channels in the proliferation, migration, and invasion of blood cells., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)