title: 5-Azacytidine induces changes in electrophysiological properties of human mesenchymal stem cells.
abstract: Previously, mouse bone marrow-derived stem cells (MSC) treated with the unspecific DNA methyltransferase inhibitor 5-azacytidine were reported to differentiate into cardiomyocytes. The aim of the present study was to investigate the efficiency of a similar differentiation strategy in human mononuclear cells obtained from healthy bone marrow donors. After 1-3 passages, cultures were exposed for 24 h to 5-azacytidine (3 mciroM) followed by 6 weeks of further culture. Drug treatment did not induce expression of myogenic marker MyoD or cardiac markers Nkx2.5 and GATA-4 and did not yield beating cells during follow-up. In patch clamp experiments, approximately 10-15% of treated and untreated cells exhibited L-type Ca(2+) currents. Almost all cells showed outwardly rectifying K(+) currents of rapid or slow activation kinetics. Mean current amplitude at +60 mV doubled after 6 weeks of treatment compared with time-matched controls. Membrane capacitance of treated cells was significantly larger than in controls 2 weeks after treatment and remained high after 6 weeks. Expression levels of mRNAs for the K(+) channels Kv1.1, Kv1.5, Kv2.1, Kv4.3 and KCNMA1 and for the Ca(2+) channel Ca(v)1.2 were not affected by 5-azacytidine. Treatment with potassium channel blockers tetraethylammonium and clofilium at concentrations shown previously to inhibit rapid or slowly activating K(+) currents of hMSC inhibited proliferation of these cells. Our results suggest that despite the absence of differentiation of hMSC into cardiomyocytes, treatment with 5-azacytidine caused profound changes in current density.
authors.affiliation: Department of Pharmacology and Toxicology, Dresden University of Technology, Fetscherstr. 74, D-01307 Dresden, Germany. balana@salk.edu
authors.forename: Bartosz
authors.initials: B
authors.lastname: Balana
authors.forename: Cecilia
authors.initials: C
authors.lastname: Nicoletti
authors.forename: Ihor
authors.initials: I
authors.lastname: Zahanich
authors.forename: Eva M
authors.initials: EM
authors.lastname: Graf
authors.forename: Torsten
authors.initials: T
authors.lastname: Christ
authors.forename: Sabine
authors.initials: S
authors.lastname: Boxberger
authors.forename: Ursula
authors.initials: U
authors.lastname: Ravens
mesh_terms: D001374:Azacitidine / Q000494:pharmacology*; D015220:Calcium Channels / Q000378:metabolism / Q000502:physiology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004594:Electrophysiology; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D015221:Potassium Channels / Q000378:metabolism / Q000502:physiology
chemical_list: D015220:Calcium Channels; D015221:Potassium Channels; D001374:Azacitidine