title: Beta cells within single human islets originate from multiple progenitors.
abstract: BACKGROUND
  In both humans and rodents, glucose homeostasis is controlled by micro-organs called islets of Langerhans composed of beta cells, associated with other endocrine cell types. Most of our understanding of islet cell differentiation and morphogenesis is derived from rodent developmental studies. However, little is known about human islet formation. The lack of adequate experimental models has restricted the study of human pancreatic development to the histological analysis of different stages of pancreatic development. Our objective was to develop a new experimental model to (i) transfer genes into developing human pancreatic cells and (ii) validate gene transfer by defining the clonality of developing human islets.
  
  
  RESULTS
  In this study, a unique model was developed combining ex vivo organogenesis from human fetal pancreatic tissue and cell type-specific lentivirus-mediated gene transfer. Human pancreatic progenitors were transduced with lentiviruses expressing GFP under the control of an insulin promoter and grafted to severe combined immunodeficient mice, allowing human beta cell differentiation and islet morphogenesis. By performing gene transfer at low multiplicity of infection, we created a chimeric graft with a subpopulation of human beta cells expressing GFP and found both GFP-positive and GFP-negative beta cells within single islets.
  
  
  CONCLUSIONS
  The detection of both labeled and unlabeled beta cells in single islets demonstrates that beta cells present in a human islet are derived from multiple progenitors thus providing the first dynamic analysis of human islet formation during development. This human transgenic-like tool can be widely used to elucidate dynamic genetic processes in human tissue formation.
authors.affiliation: University Paris-Descartes, Faculty of Medicine, INSERM, Necker Hospital, U845, Paris, France.
authors.forename: Raphaël
authors.initials: R
authors.lastname: Scharfmann
authors.forename: Xiangwei
authors.initials: X
authors.lastname: Xiao
authors.forename: Harry
authors.initials: H
authors.lastname: Heimberg
authors.forename: Jacques
authors.initials: J
authors.lastname: Mallet
authors.forename: Philippe
authors.initials: P
authors.lastname: Ravassard
mesh_terms: D000293:Adolescent; D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D005260:Female; D016332:Fetal Tissue Transplantation / Q000379:methods; D018014:Gene Transfer Techniques; D005934:Glucagon / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000235:genetics / Q000378:metabolism; D050417:Insulin-Secreting Cells / Q000378:metabolism / Q000502:physiology*; D007515:Islets of Langerhans / Q000166:cytology / Q000196:embryology / Q000378:metabolism / Q000502:physiology*; D016381:Islets of Langerhans Transplantation / Q000379:methods; D016086:Lentivirus / Q000235:genetics; D008297:Male; D051379:Mice; D016513:Mice, SCID; D009024:Morphogenesis / Q000235:genetics; D013234:Stem Cells / Q000502:physiology*; D014183:Transplantation, Heterologous
chemical_list: D007328:Insulin; D049452:Green Fluorescent Proteins; D005934:Glucagon