title: Functional Maturation of Induced Pluripotent Stem Cell Hepatocytes in Extracellular Matrix-A Comparative Analysis of Bioartificial Liver Microenvironments.
abstract: : Induced pluripotent stem cells (iPSCs) are new diagnostic and potentially therapeutic tools to model disease and assess the toxicity of pharmaceutical medications. A common limitation of cell lineages derived from iPSCs is a blunted phenotype compared with fully developed, endogenous cells. We examined the influence of novel three-dimensional bioartificial microenvironments on function and maturation of hepatocyte-like cells differentiated from iPSCs and grown within an acellular, liver-derived extracellular matrix (ECM) scaffold. In parallel, we also compared a bioplotted poly-l-lactic acid (PLLA) scaffold that allows for cell growth in three dimensions and formation of cell-cell contacts but is infused with type I collagen (PLLA-collagen scaffold) alone as a "deconstructed" control scaffold with narrowed biological diversity. iPSC-derived hepatocytes cultured within both scaffolds remained viable, became polarized, and formed bile canaliculi-like structures; however, cells grown within ECM scaffolds had significantly higher P450 (CYP2C9, CYP3A4, CYP1A2) mRNA levels and metabolic enzyme activity compared with iPSC hepatocytes grown in either bioplotted PLLA collagen or Matrigel sandwich control culture. Additionally, the rate of albumin synthesis approached the level of primary cryopreserved hepatocytes with lower transcription of fetal-specific genes, α-fetoprotein and CYP3A7, compared with either PLLA-collagen scaffolds or sandwich culture. These studies show that two acellular, three-dimensional culture systems increase the function of iPSC-derived hepatocytes. However, scaffolds derived from ECM alone induced further hepatocyte maturation compared with bioplotted PLLA-collagen scaffolds. This effect is likely mediated by the complex composition of ECM scaffolds in contrast to bioplotted scaffolds, suggesting their utility for in vitro hepatocyte assays or drug discovery.
  
  
  
  Through the use of novel technology to develop three-dimensional (3D) scaffolds, the present study demonstrated that hepatocyte-like cells derived via induced pluripotent stem cell (iPSC) technology mature on 3D extracellular matrix scaffolds as a result of 3D matrix structure and scaffold biology. The result is an improved hepatic phenotype with increased synthetic and catalytic potency, an improvement on the blunted phenotype of iPSC-derived hepatocytes, a critical limitation of iPSC technology. These findings provide insight into the influence of 3D microenvironments on the viability, proliferation, and function of iPSC hepatocytes to yield a more mature population of cells for cell toxicity studies and disease modeling.
authors.affiliation: Comprehensive Transplant Center, Northwestern University Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
authors.affiliation: Querrey Institute for BioNanotechnology, Northwestern University, Chicago, Illinois, USA Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois, USA.
authors.forename: Adam E
authors.initials: AE
authors.lastname: Jakus
authors.affiliation: Instituto de Investigación Sanitaria de Aragón, Centro de Investigación Biomédica de Aragón, Zaragoza, Spain Centro de Investigación Biomédica en Red en el Área temática de Enfermedades Hepáticas (CIBERehd), Zaragoza, Spain Fundacion ARAID, Zaragoza, Spain.
authors.forename: Pedro M
authors.initials: PM
authors.lastname: Baptista
authors.affiliation: Wake Forest Institute for Regenerative Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA.
authors.forename: Shay
authors.initials: S
authors.lastname: Soker
authors.affiliation: Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA Department of Pathology, Thomas E. Starzl Transplantation Institute, and McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Soto-Gutierrez
authors.affiliation: Comprehensive Transplant Center, Northwestern University Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA Department of Surgery, Northwestern University Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Abecassis
authors.affiliation: Comprehensive Transplant Center, Northwestern University Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA Querrey Institute for BioNanotechnology, Northwestern University, Chicago, Illinois, USA Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois, USA Department of Surgery, Northwestern University Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, USA.
authors.forename: Ramille N
authors.initials: RN
authors.lastname: Shah
authors.affiliation: Comprehensive Transplant Center, Northwestern University Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA Querrey Institute for BioNanotechnology, Northwestern University, Chicago, Illinois, USA Department of Surgery, Northwestern University Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, USA Department of Surgery, Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois, USA Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois, USA jason.wertheim@northwestern.edu.
authors.forename: Jason A
authors.initials: JA
authors.lastname: Wertheim
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques / Q000379:methods; D005109:Extracellular Matrix / Q000378:metabolism; D022781:Hepatocytes / Q000166:cytology*; D006801:Humans; D007150:Immunohistochemistry; D057026:Induced Pluripotent Stem Cells / Q000166:cytology*; D019164:Liver, Artificial; D008297:Male; D008854:Microscopy, Electron; D011091:Polyesters; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds
chemical_list: D011091:Polyesters; C033616:poly(lactide)
keywords: Induced pluripotent stem cells; Liver; Stem cell-microenvironment interactions; Stem/progenitor cell; Tissue regeneration