Human mesenchymal stem cells stimulated by TNF-alpha, LPS, or hypoxia produce growth factors by an NF kappa B- but not JNK-dependent mechanism.
Understanding the mechanisms by which adult stem cells produce growth factors may represent an important way to optimize their beneficial paracrine and autocrine effects. Components of the wound milieu may stimulate growth factor production to promote stem cell-mediated repair. We hypothesized that tumor necrosis factor-alpha (TNF-alpha), endotoxin (LPS), or hypoxia may activate human mesenchymal stem cells (MSCs) to increase release of vascular endothelial growth factor (VEGF), fibroblast growth factor 2 (FGF2), insulin-like growth factor 1 (IGF-1), or hepatocyte growth factor (HGF) and that nuclear factor-kappa B (NF kappa B), c-Jun NH2-terminal kinase (JNK), and extracellular signal-regulated kinase (ERK) mediates growth factor production from human MSCs. To study this, human MSCs were harvested, passaged, divided into four groups (100,000 cells, triplicates) and treated as follows: 1) with vehicle; 2) with stimulant alone [24 h LPS (200 ng/ml), 24 h TNF-alpha (50 ng/ml), or 24 h hypoxia (1% O2)]; 3) with inhibitor alone [NF kappa B (PDTC, 1 mM), JNK (TI-JIP, 10 microM), or ERK (ERK Inhibitor II, 25 microM)]; and 4) with stimulant and the various inhibitors. After 24 h incubation, MSC activation was determined by measuring supernatants for VEGF, FGF2, IGF-1, or HGF (ELISA). TNF-alpha, LPS, and hypoxia significantly increased human MSC VEGF, FGF2, HGF, and IGF-1 production versus controls. Stem cells exposed to injury demonstrated increased activation of NF kappa B, ERK, and JNK. VEGF, FGF2, and HGF expression was significantly reduced by NF kappa B inhibition (50% decrease) but not ERK or JNK inhibition. Moreover, ERK, JNK, and NF kappa B inhibitor alone did not activate MSC VEGF expression over controls. Various stressors activate human MSCs to increase VEGF, FGF2, HGF, and IGF-1 expression, which depends on an NFkB mechanism.
Crisostomo
Paul R
PR
Departments of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA.
Wang
Yue
Y
Markel
Troy A
TA
Wang
Meijing
M
Lahm
Tim
T
Meldrum
Daniel R
DR
D015687:Cell Hypoxia; D048430:Cell Shape; D002478:Cells, Cultured; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D017228:Hepatocyte Growth Factor / Q000378:metabolism; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D059630:Mesenchymal Stem Cells / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D019899:Paracrine Communication; D010446:Peptide Fragments / Q000494:pharmacology; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
C066855:HGF protein, human; D036341:Intercellular Signaling Peptides and Proteins; D008070:Lipopolysaccharides; D016328:NF-kappa B; D010446:Peptide Fragments; D047428:Protein Kinase Inhibitors; D014409:Tumor Necrosis Factor-alpha; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D016222:Fibroblast Growth Factor 2; D017228:Hepatocyte Growth Factor; D007334:Insulin-Like Growth Factor I; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases