title: Electrophysiological properties of neurosensory progenitors derived from human embryonic stem cells.
abstract: In severe cases of sensorineural hearing loss where the numbers of auditory neurons are significantly depleted, stem cell-derived neurons may provide a potential source of replacement cells. The success of such a therapy relies upon producing a population of functional neurons from stem cells, to enable precise encoding of sound information to the brainstem. Using our established differentiation assay to produce sensory neurons from human stem cells, patch-clamp recordings indicated that all neurons examined generated action potentials and displayed both transient sodium and sustained potassium currents. Stem cell-derived neurons reliably entrained to stimuli up to 20 pulses per second (pps), with 50% entrainment at 50 pps. A comparison with cultured primary auditory neurons indicated similar firing precision during low-frequency stimuli, but significant differences after 50 pps due to differences in action potential latency and width. The firing properties of stem cell-derived neurons were also considered relative to time in culture (31-56 days) and revealed no change in resting membrane potential, threshold or firing latency over time. Thus, while stem cell-derived neurons did not entrain to high frequency stimulation as effectively as mammalian auditory neurons, their electrical phenotype was stable in culture and consistent with that reported for embryonic auditory neurons.
authors.affiliation: Department of Otolaryngology, University of Melbourne, Royal Victorian Eye and Ear Hospital, Level 2, 32 Gisborne Street, East Melbourne, VIC 3002, Australia; Department of Medicine, St Vincent's Hospital, University of Melbourne, Level 4, Clinical Sciences Building, 29 Regent Street, Fitzroy, VIC 3065, Australia. Electronic address: k.needham@unimelb.edu.au.
authors.forename: Karina
authors.initials: K
authors.lastname: Needham
authors.affiliation: Department of Otolaryngology, University of Melbourne, Royal Victorian Eye and Ear Hospital, Level 2, 32 Gisborne Street, East Melbourne, VIC 3002, Australia. Electronic address: t.hyakumura@pgrad.unimelb.edu.au.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Hyakumura
authors.affiliation: Department of Otolaryngology, University of Melbourne, Royal Victorian Eye and Ear Hospital, Level 2, 32 Gisborne Street, East Melbourne, VIC 3002, Australia. Electronic address: gunan@unimelb.edu.au.
authors.forename: Niliksha
authors.initials: N
authors.lastname: Gunewardene
authors.affiliation: Centre for Neural Engineering, NICTA, University of Melbourne, 203 Bouverie Street, Parkville, VIC 3010, Australia. Electronic address: mdottori@unimelb.edu.au.
authors.forename: Mirella
authors.initials: M
authors.lastname: Dottori
authors.affiliation: Department of Otolaryngology, University of Melbourne, Royal Victorian Eye and Ear Hospital, Level 2, 32 Gisborne Street, East Melbourne, VIC 3002, Australia; Department of Audiology and Speech Pathology, University of Melbourne, 550 Swanston Street, Parkville, VIC 3010, Australia; Bionics Institute, 384-388 Albert Street, East Melbourne, VIC 3002, Australia. Electronic address: b.nayagam@unimelb.edu.au.
authors.forename: Bryony A
authors.initials: BA
authors.lastname: Nayagam
mesh_terms: D002454:Cell Differentiation; D002460:Cell Line; D055724:Electrophysiological Phenomena; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000502:physiology; D006801:Humans; D018408:Patch-Clamp Techniques; D011984:Sensory Receptor Cells / Q000166:cytology* / Q000378:metabolism / Q000502:physiology*; D013234:Stem Cells / Q000166:cytology / Q000502:physiology
keywords: 4-AP; 4-aminopyridine; 4-ethylphenylamino-1,2-dimethyl-6-methylaminopyrimidinium chloride; AN; AP; AP(Max); BDNF; DIV; EGF; HCN; HFFs; I(K); I(Na); I(h); K; NBM; NFM; NS; NT3; NTs; Neurobasal media; R(IN); R(S); RMP; RNA; SEM; TEA; TTX; V(h); Y27; ZD7288; action potential; auditory neuron; bFGF; basic fibroblast growth factor; brain derived neurotrophic factor; cDNA; complementary deoxyribonucleic acid; days in vitro; epidermal growth factor; hESC; half-activation voltage; human embryonic stem cell; human foreskin fibroblast feeders; hyperpolarization-activated current; hyperpolarization-activated cyclic nucleotide-gated channels; input resistance; maximum number of action potentials; neurofilament; neurosphere; neurotrophin 3; neurotrophins; potassium current; pps; pulses per second; qRT-PCR; quantitative real time polymerase chain reaction; resting membrane potential; ribonucleic acid; series resistance; slope factor; small peptide Y27632; sodium current; standard error of the mean; tetraethylammonium; tetrodotoxin