title: Modulation of hematopoietic progenitor cell fate in vitro by varying collagen oligomer matrix stiffness in the presence or absence of osteoblasts.
abstract: To recreate the in vivo hematopoietic cell microenvironment or niche and to study the impact of extracellular matrix (ECM) biophysical properties on hematopoietic progenitor cell (HPC) proliferation and function, mouse bone-marrow derived HPC (Lin-Sca1+cKit+/(LSK) were cultured within three-dimensional (3D) type I collagen oligomer matrices. To generate a more physiologic milieu, 3D cultures were established in both the presence and absence of calvariae-derived osteoblasts (OB). Collagen oligomers were polymerized at varying concentration to give rise to matrices of different fibril densities and therefore matrix stiffness (shear storage modulus, 50-800 Pa). Decreased proliferation and increased clonogenicity of LSK cells was associated with increase of matrix stiffness regardless of whether OB were present or absent from the 3D culture system. Also, regardless of whether OB were or were not added to the 3D co-culture system, LSK within 800 Pa collagen oligomer matrices maintained the highest percentage of Lin-Sca1+ cells as well as higher percentage of cells in quiescent state (G0/G1) compared to 50 Pa or 200Pa matrices. Collectively, these data illustrate that biophysical features of collagen oligomer matrices, specifically fibril density-induced modulation of matrix stiffness, provide important guidance cues in terms of LSK expansion and differentiation and therefore maintenance of progenitor cell function.
authors.affiliation: Medicine/Division of Hematology-Oncology, Indiana University School of Medicine, Indianapolis, IN, United States. Electronic address: bchittet@iu.edu.
authors.forename: Brahmananda Reddy
authors.initials: BR
authors.lastname: Chitteti
authors.affiliation: Orthopaedic Surgery, Indiana University School of Medicine, Indianapolis, IN, United States; Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, United States; Biomedical Engineering, Indiana University Purdue University Indianapolis, Indianapolis, IN, United States.
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Kacena
authors.affiliation: Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States.
authors.forename: Sherry L
authors.initials: SL
authors.lastname: Voytik-Harbin
authors.affiliation: Medicine/Division of Hematology-Oncology, Indiana University School of Medicine, Indianapolis, IN, United States; Pediatrics/Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, United States; Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, United States.
authors.forename: Edward F
authors.initials: EF
authors.lastname: Srour
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000378:metabolism / Q000502:physiology; D016923:Cell Death / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation / Q000502:physiology; D018920:Coculture Techniques / Q000379:methods*; D003094:Collagen / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism / Q000502:physiology; D016193:G1 Phase / Q000502:physiology; D006412:Hematopoietic Stem Cells / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D010006:Osteoblasts / Q000502:physiology*; D016192:Resting Phase, Cell Cycle / Q000502:physiology; D013234:Stem Cells / Q000378:metabolism / Q000502:physiology*
chemical_list: D003094:Collagen
keywords: Biophysical properties; Collagen oligomers; Hematopoietic stem cells; Matrix stiffness; Osteoblasts; Three-dimensional culture