title: CD133+ adult human retinal cells remain undifferentiated in Leukaemia Inhibitory Factor (LIF).
abstract: BACKGROUND
  CD133 is a cell surface marker of haematopoietic stem and progenitor cells. Leukaemia inhibitory factor (LIF), sustains proliferation and not differentiation of embryonic stem cells. We used CD133 to purify adult human retinal cells and aimed to determine what effect LIF had on these cultures and whether they still had the ability to generate neurospheres.
  
  
  METHODS
  Retinal cell suspensions were derived from adult human post-mortem tissue with ethical approval. With magnetic automated cell sorting (MACS) CD133+ retinal cells were enriched from post mortem adult human retina. CD133+ retinal cell phenotype was analysed by flow cytometry and cultured cells were observed for proliferative capacity, neuropshere generation and differentiation with or without LIF supplementation.
  
  
  RESULTS
  We demonstrated purification (to 95%) of CD133+ cells from adult human postmortem retina. Proliferating cells were identified through BrdU incorporation and expression of the proliferation markers Ki67 and Cyclin D1. CD133+ retinal cells differentiated whilst forming neurospheres containing appropriate lineage markers including glia, neurons and photoreceptors. LIF maintained CD133+ retinal cells in a proliferative and relatively undifferentiated state (Ki67, Cyclin D1 expression) without significant neurosphere generation. Differentiation whilst forming neurospheres was re-established on LIF withdrawal.
  
  
  CONCLUSIONS
  These data support the evidence that CD133 expression characterises a population of cells within the resident adult human retina which have progenitor cell properties and that their turnover and differentiation is influenced by LIF. This may explain differences in retinal responses observed following disease or injury.
authors.affiliation: Academic Unit of Ophthalmology, Department of Clinical Sciences South Bristol, University of Bristol, Bristol Eye Hospital, Lower Maudlin Street, Bristol BS12LX, UK. debbie.carter@bristol.ac.uk
authors.forename: Debra A
authors.initials: DA
authors.lastname: Carter
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Dick
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Mayer
mesh_terms: D000071916:AC133 Antigen; D000328:Adult; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000032:analysis; D001973:Bromodeoxyuridine / Q000032:analysis / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects*; D002478:Cells, Cultured; D019938:Cyclin D1 / Q000032:analysis / Q000096:biosynthesis; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D005434:Flow Cytometry; D006023:Glycoproteins; D006801:Humans; D019394:Ki-67 Antigen / Q000032:analysis / Q000096:biosynthesis; D053605:Leukemia Inhibitory Factor / Q000494:pharmacology*; D009457:Neuroglia / Q000166:cytology / Q000378:metabolism; D010455:Peptides; D020419:Photoreceptor Cells, Vertebrate / Q000166:cytology / Q000378:metabolism; D012160:Retina / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D013234:Stem Cells / Q000187:drug effects / Q000378:metabolism
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; D000943:Antigens, Differentiation; C530104:CCND1 protein, human; D006023:Glycoproteins; D019394:Ki-67 Antigen; D053605:Leukemia Inhibitory Factor; C000606023:PROM1 protein, human; D010455:Peptides; D016222:Fibroblast Growth Factor 2; D019938:Cyclin D1; D001973:Bromodeoxyuridine