IL-6 and TGF-α costimulate mesenchymal stem cell vascular endothelial growth factor production by ERK-, JNK-, and PI3K-mediated mechanisms.
Mesenchymal stem cells (MSCs) protect ischemic tissues in part through paracrine growth factor production. IL-6, which is upregulated in the heart during ischemia, has been shown to enhance stem cell proliferation and migration. The effect of IL-6 on MSC paracrine function, however, remains unknown. In addition, TGF-α increases MSC vascular endothelial growth factor (VEGF) production and may share downstream signaling pathways with IL-6 involving ERK, JNK, and PI3K. We hypothesize that cotreatment with IL-6 and TGF-α will result in greater MSC VEGF production than by either treatment alone via these signaling pathways. Murine MSCs were treated with IL-6 (0.05 ng/mL) with or without TGF-α (250 ng/mL) and in combination with inhibitors of ERKI/II, JNK, and PI3K for 24 h. Vascular endothelial growth factor concentrations in the supernatants were measured using enzyme-linked immunosorbent assay. Phosphorylation of ERK, JNK, and PI3K was measured using Western blot analysis. IL-6 increased MSC VEGF production at a dose of 0.05 ng/mL, and the combination of IL-6 and TGF-α (250 ng/mL) increased VEGF production to a greater extent than IL-6 or TGF-α alone. IL-6 induced phosphorylation of ERK, JNK, and PI3K, and inhibition of each suppressed IL-6-induced VEGF production. TGF-α cotreatment overcame VEGF suppression after ERK2 inhibition but not ERK1, JNK, or PI3K. These data suggest that IL-6 stimulates MSC VEGF production alone and additively with TGF-α via ERK-, JNK-, and PI3K-mediated mechanisms. IL-6 and TGF-α cotreatment may be a useful strategy for enhancing MSC VEGF production and cardioprotection during myocardial ischemia.
Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana, USA.
Jeremy L
JL
Herrmann
Brent R
BR
Weil
Aaron M
AM
Abarbanell
Yue
Y
Wang
Jeffrey A
JA
Poynter
Mariuxi C
MC
Manukyan
Daniel R
DR
Meldrum
D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism*; D015850:Interleukin-6 / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D008297:Male; D059630:Mesenchymal Stem Cells / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism*; D016211:Transforming Growth Factor alpha / Q000494:pharmacology*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
D015850:Interleukin-6; D016211:Transforming Growth Factor alpha; D042461:Vascular Endothelial Growth Factor A; D019869:Phosphatidylinositol 3-Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases