The voltage-gated proton channel hHv1 is functionally expressed in human chorion-derived mesenchymal stem cells

Abstract

The voltage-gated proton channel Hv1 is widely expressed, among others, in immune and cancer cells, it provides an efficient cytosolic H + extrusion mechanism and regulates vital functions such as oxidative burst, migration and proliferation. Here we demonstrate the presence of human Hv1 (hHv1) in the placenta/chorion-derived mesenchymal stem cells (cMSCs) using RT-PCR. The voltage-and pHdependent gating of the current is similar to that of hHv1 expressed in cell lines and that the current is blocked by 5-chloro-2-guanidinobenzimidazole (ClGBI) and activated by arachidonic acid (AA). Inhibition of hHv1 by ClGBI significantly decreases mineral matrix production of cMSCs induced by conditions mimicking physiological or pathological (inorganic phosphate, Pi) induction of osteogenesis. Wound healing assay and single cell motility analysis show that ClGBI significantly inhibits the migration of cMSCs. Thus, seminal functions of cMSCs are modulated by hHv1 which makes this channel as an attractive target for controlling advantages/disadvantages of MSCs therapy.Mesenchymal stem cells (MSCs) are multipotent cells with intensive proliferative capacity and ability to differentiate into various cell types (osteoblasts, chondroblasts, myocytes, adipocytes etc.) 1,2 . MSCs were originally isolated from bone marrow, and were found later in numerous organs and tissues, including adipose tissue, periosteum, synovial membrane, articular cartilage, umbilical cord and placenta, among others 1,3 . The use of MSCs is a novel therapeutic strategy for regenerative medicine 4,5 , however, their application is not limited to repairing and replacing the impaired organs, rather, the immunomodulatory and anti-inflammatory properties 5-9 of MSCs are also important 10,11 . Placenta-derived mesenchymal stem cells (cMSCs) possess excellent immunoregulatory properties, therefore, the chorionic plate of the placenta may be an attractive source for stem cells to be used in cell therapy and tissue engineering 3,12 . In most cases, systemic delivery is preferred for the clinical applications which requires the homing and migration of MSCs to the target tissue. In line with these MSCs have a capacity to migrate into the injured and inflamed environment 13,14 .Bioelectric signaling and pH regulation via ion channels and pumps are known to play a role in a wide range of cell functions, including cell proliferation, migration, differentiation, apoptosis but this aspect of stem cell biology seems to be poorly understood 10,15 . Multiple ion channels were reported earlier to be present in human MSCs, for example K + channels, Na + and Cl − channels 16,17 , but data are missing in the literature for the existence of the human voltage-gated proton channels (hHv1) in mesenchymal stem cells. At the same time hHv1 channels are widespread; they can be found in various mammalian cells [18][19][20][21][22][23][24] , such as macrophages 25 , B-lymphocytes 26,27 , oocytes 28 , osteoclasts 29,30 , skeletal muscle cells 31 , as well as cancer cells 32,33 , for exampl...

Multiple mechanisms contribute to fluorometry signals from the voltage-gated proton channel

“…The Hv1 protein could be subsequently associated with the previously well-known proton current (first described almost four decades ago 13 ) and then was named Hv1, voltage-gated proton channel. By now it is known that Hv1 is expressed in multiple cell types in the human body, such as in different immune cells 14 , 15 , lung epithelial cells 16 , sperm 17 , pancreatic β-cells 18 , 19 and stem cells 20 . The presence and possible functional relevance of Hv1 have been described in cancer cells as well 21 – 24 .…”

HIFs: New arginine mimic inhibitors of the Hv1 channel with improved VSD–ligand interactions

“…Two major strategies have proved successful in developing ligands targeting the Hv1 VSD: one focused on the use of peptide toxins binding the channel extracellular side ( Alabi et al, 2007 ; Tang et al, 2020 ; Zhao et al, 2018 ) and the other focused on small organic molecules targeting the channel intracellular side ( Hong et al, 2014 ; Hong et al, 2013 ; Kalia and Swartz, 2013 ; Pupo and Gonzalez León, 2014 ). Some of these ligands have found applications as pharmacological tools to study the gating and permeation mechanisms of proton-conducting VSDs ( Chamberlin et al, 2014 ; Gianti et al, 2016 ; Hong et al, 2015 ; Qiu et al, 2013 ; Wobig et al, 2020 ) and the role of Hv1-mediated proton currents in cellular physiology ( Asuaje et al, 2017 ; Mészáros et al, 2020 ; Rennhack et al, 2017 ; Zhao et al, 2018 ). Drug-screening approaches on native proton currents or on other ion channels have led to the identification of additional potential ligands ( Kornilov et al, 2014 ; Shin et al, 2015 ; Shin and Song, 2014 ; Song et al, 2012 ).…”

Intracellular pH Regulation: Characterization and Functional Investigation of H+ Transporters in Stylophora Pistillata

“…In addition, cells in the oral tissue are enriched with zooxanthellae [68], that produce and incorporate high levels of anion superoxide (O 2 − ) and Zn + 2 , which accumulate in the host cytoplasm [69][70][71]. In this regard, spiH v CN1.2 might favour the exit of H + on the basolateral membrane of these cells, as reported in human osteoblasts [72], preventing membrane depolarization to extreme negative voltages associated to O 2 − electron transfer. To notice also that the lower sensitivity of spiH v CN1.2 to Zn + 2 , compared to spiH v CN1.1 (see Discussion 3.1.3), could be correlated to the higher Zn + 2 concentration levels in the oral (symbiotic) cells [63,[73][74][75][76].…”