title: Impedance flow cytometry gauges proliferative capacity by detecting TRPC1 expression.
abstract: When examined, the expansion of many stem cell classes has been shown to be facilitated by mechanically-regulated calcium entry from the extracellular space that also helps direct their developmental programs towards mechanosensitive tissues such as muscle, bone, and connective tissues. Cation channels of the transient receptor potential C class (TRPC) are the predominant conduit for calcium entry into proliferating myoblasts. Nonetheless, methods to non-invasively study this calcium-entry pathway are still in their infancy. Here we show that a microfluidic configuration of impedance-based flow cytometry (IFC) provides a method to detect TRP channel expression in cells at high throughput. Using this technology we discern changes in the IFC signal that correlates with the functional expression of TRPC1 channels and coincides with cell proliferation. Pharmacological agents, mechanical conditions or malignant states that alter the expression of TRPC1 channels are reflected in the IFC signal accordingly, whereas pharmacological agents that alter cation-permeation through TRPC1 channels, or ionophores that independently increase calcium entry across the membrane, have little effect. Our results suggest that IFC detects changes in whole-cell membrane organization associated with TRPC1 activation and surface expression, rather than cation permeation through the channel per se. IFC-based technologies thus have the potential to identify living stem cells in their earliest stages of expansion without staining or chemical fixation.
authors.affiliation: Institute for Biomechanics, ETH Zürich, Switzerland.
authors.forename: Sara
authors.initials: S
authors.lastname: Crocetti
authors.forename: Christian
authors.initials: C
authors.lastname: Beyer
authors.forename: Silvio
authors.initials: S
authors.lastname: Unternährer
authors.forename: Tatiana
authors.initials: T
authors.lastname: Benavides Damm
authors.forename: Grit
authors.initials: G
authors.lastname: Schade-Kampmann
authors.forename: Monika
authors.initials: M
authors.lastname: Hebeisen
authors.forename: Marco
authors.initials: M
authors.lastname: Di Berardino
authors.forename: Jürg
authors.initials: J
authors.lastname: Fröhlich
authors.forename: Alfredo
authors.initials: A
authors.lastname: Franco-Obregón
mesh_terms: D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics; D049109:Cell Proliferation / Q000187:drug effects / Q000235:genetics*; D017097:Electric Impedance; D005434:Flow Cytometry / Q000379:methods*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D032446:Myoblasts / Q000378:metabolism; D009369:Neoplasms / Q000175:diagnosis / Q000473:pathology*; D013234:Stem Cells / Q000473:pathology; D050052:TRPC Cation Channels / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D050052:TRPC Cation Channels; C096351:transient receptor potential cation channel, subfamily C, member 1; D002118:Calcium
keywords: calcium flux; cancer cells; cell cycle; flow cytometry; muscle; myoblasts; progenitor cells; stem cells; tissue regeneration; transient receptor potential channels (TRP)