title: Human induced pluripotent stem cell-derived neural stem cells survive, migrate, differentiate, and improve neurologic function in a rat model of middle cerebral artery occlusion.
abstract: BACKGROUND
  Stroke is a major cause of permanent neurologic damage, with few effective treatments available to restore lost function. Induced pluripotent stem cells (iPSCs) have the potential to generate all cell types in vitro and can be generated from a stroke patient. Therefore, iPSCs are attractive donor sources of genetically identical "patient-specific" cells to hold promise in therapy for stroke. In the present study, we established a four-stage culture system by using serum-free medium and retinoic acid (RA) to differentiate iPSCs into neural stem cells (NSCs) effectively and stably. Our hypothesis was that iPSC-derived NSCs would survive, migrate, and differentiate in vivo, and improve neurologic function after transplantation into the brains of rats with ischemic stroke.
  
  
  METHODS
  Human iPSCs (iPS-S-01) and human ESCs (HuES17) were used to differentiate into NSCs by using our four-stage culture system. iPSCs and differentiated NSCs were characterized by immunocytochemistry staining and reverse transcription-polymerase chain reaction (RT-PCR) analysis. After establishment of focal cerebral ischemia with occlusion of the middle cerebral artery (MCA) and cell transplantation, animals were killed at 1 week and 2 weeks to analyze survival, migration, and differentiation of implanted cells in brain tissue. Animal behavior was evaluated via rope grabbing, beam walking, and Morris water maze tests.
  
  
  RESULTS
  iPSCs were efficiently induced into NSCs by using a newly established four-stage induction system in vitro. iPSCs expressed pluripotency-associated genes Oct4, Sox2, and Nanog before NSC differentiation. The iPSC-derived NSCs spontaneously differentiated into neurons and astrocytes, which highly express β-tubulin and glial fibrillary acidic protein (GFAP), respectively. On transplantation into the striatum, CM-DiI labeled iPSC-derived NSCs were found to migrate into the ischemia area at 1 week and 2 weeks, and animal-function recovery was significantly improved in comparison with control groups at 3 weeks.
  
  
  CONCLUSIONS
  The four-stage induction system is stable and effective to culture, differentiate, and induce iPSCs to NSCs by using serum-free medium combined with retinoic acid (RA). Implanted iPSC-derived NSCs were able to survive, migrate into the ischemic brain area to differentiate into mature neural cells, and seem to have potential to restore lost neurologic function from damage due to stroke in a rat model.
authors.forename: Ting
authors.initials: T
authors.lastname: Yuan
authors.forename: Wei
authors.initials: W
authors.lastname: Liao
authors.forename: Nian-Hua
authors.initials: NH
authors.lastname: Feng
authors.forename: Yuan-Lei
authors.initials: YL
authors.lastname: Lou
authors.forename: Xin
authors.initials: X
authors.lastname: Niu
authors.forename: Ai-Jun
authors.initials: AJ
authors.lastname: Zhang
authors.forename: Yang
authors.initials: Y
authors.lastname: Wang
authors.forename: Zhi-Feng
authors.initials: ZF
authors.lastname: Deng
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D004195:Disease Models, Animal; D053595:Embryonic Stem Cells / Q000166:cytology; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000166:cytology* / Q000378:metabolism; D020244:Infarction, Middle Cerebral Artery / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D008297:Male; D009043:Motor Activity; D000071317:Nanog Homeobox Protein; D064231:Nestin / Q000235:genetics / Q000378:metabolism; D058953:Neural Stem Cells / Q000166:cytology / Q000637:transplantation*; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D050814:Octamer Transcription Factor-3 / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function; D055748:SOXB1 Transcription Factors / Q000235:genetics / Q000378:metabolism; D014404:Tubulin / Q000378:metabolism
chemical_list: D018398:Homeodomain Proteins; C486780:NANOG protein, human; D000071317:Nanog Homeobox Protein; D064231:Nestin; D050814:Octamer Transcription Factor-3; C494173:POU5F1 protein, human; C527782:SOX2 protein, human; D055748:SOXB1 Transcription Factors; D014404:Tubulin