title: Functional properties of cells obtained from human cord blood CD34+ stem cells and mouse cardiac myocytes in coculture.
abstract: Prior in vitro studies suggested that different types of hematopoietic stem cells may differentiate into cardiomyocytes. The present work examined whether human CD34(+) cells from the human umbilical cord blood (hUCB), cocultured with neonatal mouse cardiomyocytes, acquire the functional properties of myocardial cells and express human cardiac genes. hUCB CD34(+) cells were cocultured onto cardiomyocytes following an infection with a lentivirus-encoding enhanced green fluorescent protein (EGFP). After 7 days, mononucleated EGFP(+) cells were tested for their electrophysiological features by patch clamp and for cytosolic [Ca(2+)] ([Ca(2+)](i)) homeostasis by [Ca(2+)](i) imaging of X-rhod1-loaded cells. Human Nkx2.5 and GATA-4 expression was examined in cocultured cell populations by real-time RT-PCR. EGFP(+) cells were connected to surrounding cells by gap junctions, acquired electrophysiological properties similar to those of cardiomyocytes, and showed action potential-associated [Ca(2+)](i) transients. These cells also exhibited spontaneous sarcoplasmic reticulum [Ca(2+)](i) oscillations and the associated membrane potential depolarization. However, RT-PCR of both cell populations showed no upregulation of human-specific cardiac genes. In conclusion, under our experimental conditions, hUCB CD34(+) cells cocultured with murine cardiomyocytes formed cells that exhibited excitation-contraction coupling features similar to those of cardiomyocytes. However, the expression of human-specific cardiac genes was undetectable by RT-PCR.
authors.affiliation: Laboratorio di Biologia Vascolare e Terapia Genica, Centro Cardiologico Monzino IRCCS, Via Parea 4, 20138 Milan, Italy.
authors.forename: Alessia
authors.initials: A
authors.lastname: Orlandi
authors.forename: Francesca
authors.initials: F
authors.lastname: Pagani
authors.forename: Daniele
authors.initials: D
authors.lastname: Avitabile
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Bonanno
authors.forename: Giovanni
authors.initials: G
authors.lastname: Scambia
authors.forename: Elisa
authors.initials: E
authors.lastname: Vigna
authors.forename: Francesca
authors.initials: F
authors.lastname: Grassi
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Eusebi
authors.forename: Sergio
authors.initials: S
authors.lastname: Fucile
authors.forename: Maurizio
authors.initials: M
authors.lastname: Pesce
authors.forename: Maurizio C
authors.initials: MC
authors.lastname: Capogrossi
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D018952:Antigens, CD34 / Q000032:analysis*; D002118:Calcium / Q000378:metabolism; D002450:Cell Communication / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics; D048430:Cell Shape; D054338:Cell Transdifferentiation; D002478:Cells, Cultured; D018920:Coculture Techniques; D005312:Fetal Blood / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D050991:GATA4 Transcription Factor / Q000235:genetics / Q000378:metabolism; D017629:Gap Junctions / Q000378:metabolism; D017930:Genes, Reporter; D005822:Genetic Vectors; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D016086:Lentivirus / Q000235:genetics; D008564:Membrane Potentials; D051379:Mice; D032383:Myocytes, Cardiac / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D013234:Stem Cells / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014161:Transduction, Genetic
chemical_list: D018952:Antigens, CD34; D050991:GATA4 Transcription Factor; C484170:GATA4 protein, human; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins; C095552:NKX2-5 protein, human; D012333:RNA, Messenger; D014157:Transcription Factors; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D002118:Calcium