title: Microcavity arrays as an in vitro model system of the bone marrow niche for hematopoietic stem cells.
abstract: In previous studies human mesenchymal stromal cells (MSCs) maintained the "stemness" of human hematopoietic progenitor cells (HPCs) through direct cell-cell contact in two-dimensional co-culture systems. We establish a three-dimensional (3D) co-culture system based on a custom-made chip, the 3(D)-KITChip, as an in vitro model system of the human hematopoietic stem cell niche. This array of up to 625 microcavities, with 300 μm size in each orientation, was inserted into a microfluidic bioreactor. The microcavities of the 3(D)-KITChip were inoculated with human bone marrow MSCs together with umbilical cord blood HPCs. MSCs used the microcavities as a scaffold to build a complex 3D mesh. HPCs were distributed three-dimensionally inside this MSC network and formed ß-catenin- and N-cadherin-based intercellular junctions to the surrounding MSCs. Using RT(2)-PCR and western blots, we demonstrate that a proportion of HPCs maintained the expression of CD34 throughout a culture period of 14 days. In colony-forming unit assays, the hematopoietic stem cell plasticity remained similar after 14 days of bioreactor co-culture, whereas monolayer co-cultures showed increasing signs of HPC differentiation and loss of stemness. These data support the notion that the 3D microenvironment created within the microcavity array preserves vital stem cell functions of HPCs more efficiently than conventional co-culture systems.
authors.affiliation: Department of Medicine V, Heidelberg University, 69120, Heidelberg, Germany. patrick.wuchter@med.uni-heidelberg.de.|HEiKA - Heidelberg Karlsruhe Research Partnership, Heidelberg University and Karlsruhe Institute of Technology, Heidelberg and Karlsruhe, Germany. patrick.wuchter@med.uni-heidelberg.de.
authors.forename: Patrick
authors.initials: P
authors.lastname: Wuchter
authors.affiliation: Department of Medicine V, Heidelberg University, 69120, Heidelberg, Germany.|HEiKA - Heidelberg Karlsruhe Research Partnership, Heidelberg University and Karlsruhe Institute of Technology, Heidelberg and Karlsruhe, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Saffrich
authors.affiliation: HEiKA - Heidelberg Karlsruhe Research Partnership, Heidelberg University and Karlsruhe Institute of Technology, Heidelberg and Karlsruhe, Germany.|Department of Complex Tissue Regeneration, MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University, Maastricht, The Netherlands.
authors.forename: Stefan
authors.initials: S
authors.lastname: Giselbrecht
authors.affiliation: Institute for Biological Interfaces-5, Karlsruhe Institute of Technology (KIT), 76344, Eggenstein-Leopoldshafen, Karlsruhe, Germany.|HEiKA - Heidelberg Karlsruhe Research Partnership, Heidelberg University and Karlsruhe Institute of Technology, Heidelberg and Karlsruhe, Germany.
authors.forename: Cordula
authors.initials: C
authors.lastname: Nies
authors.affiliation: Institute for Biological Interfaces-5, Karlsruhe Institute of Technology (KIT), 76344, Eggenstein-Leopoldshafen, Karlsruhe, Germany.|HEiKA - Heidelberg Karlsruhe Research Partnership, Heidelberg University and Karlsruhe Institute of Technology, Heidelberg and Karlsruhe, Germany.
authors.forename: Hanna
authors.initials: H
authors.lastname: Lorig
authors.affiliation: Institute for Biological Interfaces-5, Karlsruhe Institute of Technology (KIT), 76344, Eggenstein-Leopoldshafen, Karlsruhe, Germany.|HEiKA - Heidelberg Karlsruhe Research Partnership, Heidelberg University and Karlsruhe Institute of Technology, Heidelberg and Karlsruhe, Germany.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Kolb
authors.affiliation: Department of Medicine V, Heidelberg University, 69120, Heidelberg, Germany.|HEiKA - Heidelberg Karlsruhe Research Partnership, Heidelberg University and Karlsruhe Institute of Technology, Heidelberg and Karlsruhe, Germany.
authors.forename: Anthony D
authors.initials: AD
authors.lastname: Ho
authors.affiliation: Institute for Biological Interfaces-5, Karlsruhe Institute of Technology (KIT), 76344, Eggenstein-Leopoldshafen, Karlsruhe, Germany. eric.gottwald@kit.edu.|HEiKA - Heidelberg Karlsruhe Research Partnership, Heidelberg University and Karlsruhe Institute of Technology, Heidelberg and Karlsruhe, Germany. eric.gottwald@kit.edu.
authors.forename: Eric
authors.initials: E
authors.lastname: Gottwald
mesh_terms: D015703:Antigens, CD / Q000378:metabolism; D019149:Bioreactors; D015153:Blotting, Western; D001854:Bone Marrow Cells / Q000166:cytology*; D002452:Cell Count; D018929:Cell Culture Techniques / Q000295:instrumentation* / Q000379:methods*; D002469:Cell Separation; D018920:Coculture Techniques; D003114:Colony-Forming Units Assay; D005455:Fluorescent Antibody Technique; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology; D008954:Models, Biological; D060888:Real-Time Polymerase Chain Reaction; D055153:Stem Cell Niche
chemical_list: D015703:Antigens, CD
keywords: Bioreactor; Hematopoietic progenitor cells; Mesenchymal stromal cells; Microcavity array; Stem cell niche