title: Growth factor gene expression profiles of bone morphogenetic protein-2-treated human adipose stem cells seeded on calcium phosphate scaffolds in vitro.
abstract: The secretome of stem cells strongly determines the outcome of tissue engineering strategies. We investigated how the secretome of human adipose stem cells (hASCs) can be affected by substrate, BMP-2 treatment, and degree of differentiation. We hypothesized that as differentiation progresses, hASCs produce increasingly more gene products associated with processes such as angiogenesis and bone remodeling. Human ASCs were treated for 15 min with BMP-2 (10 ng/ml) to enhance osteogenic differentiation, or with vehicle. Subsequently, hASCs were seeded on plastic or on biphasic calcium phosphate (BCP) consisting of 60% hydroxyapatite and 40% β-tricalcium phosphate. A PCR array for ~150 trophic factors and differentiation-related genes was performed at day 21 of culture. A limited set of factors was quantified by qPCR at days 0, 4, 14 and 21, and/or ELISA at day 21. Compared to plastic, BCP-cultured hASCs showed ≥2-fold higher expression of ~20 factors, e.g. cytokines such as IL-6, growth factors such as FGF7 and adhesion molecules such as VCAM1. Expression of another ~50 genes was decreased ≥2-fold on BCP vs. plastic, even though hASCs differentiate better on BCP than on plastic. BMP-2-treatment increased the expression of ~30 factors by hASCs seeded on BCP, while it decreased the expression of only PGF, PPARG and PTN. Substrate affected hASC secretion of Activin A and seemed to affect P1NP release. No clear association between hASC osteogenic differentiation and growth factor expression pattern was observed. Considering our observed lack of association between the degree of differentiation and the expression of factors associated with angiogenesis and bone remodeling by hASCs, future bone regeneration studies should focus more on systematically orchestrating the secretome of stem cells, rather than on inducing osteogenic differentiation of stem cells only. Short incubation with BMP-2 may be a promising treatment to enhance both osteogenic differentiation and environmental modulation.
authors.affiliation: Dept. Oral Cell Biology, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University Amsterdam, MOVE Research Institute Amsterdam, Amsterdam, The Netherlands; Dept. Oral and Maxillofacial Surgery, Academic Centre for Dentistry Amsterdam/VU University Medical Center, MOVE Research Institute Amsterdam, Amsterdam, The Netherlands.
authors.forename: J R
authors.initials: JR
authors.lastname: Overman
authors.forename: M N
authors.initials: MN
authors.lastname: Helder
authors.forename: C M
authors.initials: CM
authors.lastname: ten Bruggenkate
authors.forename: E A J M
authors.initials: EA
authors.lastname: Schulten
authors.forename: J
authors.initials: J
authors.lastname: Klein-Nulend
authors.forename: A D
authors.initials: AD
authors.lastname: Bakker
mesh_terms: D000273:Adipose Tissue / Q000166:cytology; D055396:Bone Morphogenetic Protein 2 / Q000494:pharmacology*; D002454:Cell Differentiation; D002478:Cells, Cultured; D006801:Humans; D006882:Hydroxyapatites; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis*; D010012:Osteogenesis; D013234:Stem Cells / Q000187:drug effects / Q000378:metabolism*; D023822:Tissue Engineering; D059467:Transcriptome / Q000502:physiology*
chemical_list: C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D006882:Hydroxyapatites; D036341:Intercellular Signaling Peptides and Proteins; C074950:hydroxyapatite-beta tricalcium phosphate
keywords: (h)ASC; (human) adipose stem cell; Adipose stem cells; BCP; BMP-2; Calcium phosphate; GAPDH; Osteogenic differentiation; P1NP; PCR; Procollagen I N-Terminal Propeptide; Secretome; Trophic factors; YWHAZ; biphasic calcium phosphate; bone morphogenetic protein-2; glyceraldehyde 3-phosphate dehydrogenase; polymerase chain reaction; tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, zeta polypeptide