title: Human progenitor cells from bone marrow or adipose tissue produce VEGF, HGF, and IGF-I in response to TNF by a p38 MAPK-dependent mechanism.
abstract: Accumulating evidence suggests that progenitor cells may decrease destructive inflammation and reduce tissue loss by antiapoptotic mechanisms. However, they remain poorly characterized, and many questions remain regarding the mechanisms by which they may positively affect wound healing, tissue remodeling, or tissue regeneration. It has been speculated that various growth factors are responsible, but what components of the wound milieu stimulate progenitor cell production of growth factors and by what mechanisms? We hypothesized that tumor necrosis factor-alpha (TNF-alpha) stimulated progenitor cell secretion of vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and insulin-like growth factor I (IGF-I) by a p38 mitogen-activated protein kinase (MAPK)-dependent mechanism. Human mesenchymal stem cells (hMSCs) and human adipose progenitor cells (hAPCs) were divided into four groups: control, p38 MAPK inhibitor (p38MKI), TNF, and TNF + p38MKI. After 24 h of incubation, supernatants were harvested for ELISA of VEGF, HGF, and IGF-I. Cells were collected for Western blot analysis of p38 MAPK activation. Secretion of VEGF, HGF, and IGF-I in hMSCs and hAPCs was significantly increased by stimulation with TNF and was associated with increased activation of p38 MAPK. The p38 MAPK inhibitor decreased production of TNF-stimulated VEGF, HGF, and IGF-I in hMSCs and hAPCs. However, p38 MAPK inhibitor alone had no effect on production of growth factors. These data demonstrate that progenitor cells are potent sources of VEGF, HGF, and IGF-I. TNF, a prominent tissue cytokine, strongly stimulated production of growth factors by hMSCs and hAPCs via a p38 MAPK-dependent mechanism.
authors.affiliation: Department of Surgery, Indiana University School of Medicine, IN, USA.
authors.forename: Meijing
authors.initials: M
authors.lastname: Wang
authors.forename: Paul R
authors.initials: PR
authors.lastname: Crisostomo
authors.forename: Christine
authors.initials: C
authors.lastname: Herring
authors.forename: Kirstan K
authors.initials: KK
authors.lastname: Meldrum
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Meldrum
mesh_terms: D001854:Bone Marrow Cells / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006133:Growth Substances / Q000378:metabolism*; D017228:Hepatocyte Growth Factor / Q000378:metabolism; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000187:drug effects / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D050151:Subcutaneous Fat / Q000166:cytology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D006133:Growth Substances; D007093:Imidazoles; D011725:Pyridines; D014409:Tumor Necrosis Factor-alpha; D042461:Vascular Endothelial Growth Factor A; D017228:Hepatocyte Growth Factor; D007334:Insulin-Like Growth Factor I; D048051:p38 Mitogen-Activated Protein Kinases; C093642:SB 203580