title: Paracrine factors from human placental multipotent mesenchymal stromal cells protect endothelium from oxidative injury via STAT3 and manganese superoxide dismutase activation.
abstract: Reactive oxygen species may cause oxidative damage in the placenta, yet some mechanisms must exist to reduce or prevent such damage. We investigated whether oxidative injury to placental endothelial cells is inhibited by activation of antioxidant enzymes by paracrine factors secreted by human placental multipotent mesenchymal stromal cells (hPMSC). hPMSC-conditioned medium and umbilical endothelial cells were assayed for cytokines and cytokine receptor expression by immunoassay and real-time PCR. Endothelial cell survival was evaluated by MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt] assay and caspase 3 activity assay. tert-Butyl hydroperoxide was used to induce oxidative injury in endothelial cells, with fluorescent microscopy and flow cytometry used to detect intracellular peroxides and cell apoptosis. Western blot, real-time PCR, STAT3 DNA-binding activity assay, and STAT3 siRNA were used to assess endothelial cell antioxidant enzymes. hPMSC-conditioned medium supported endothelial cell survival and reduced endothelial cell intracellular peroxides and apoptosis. hPMSCs expressed the transcripts of the interleukin (IL) 6 cytokine family, including IL6 and leukemia-inhibitory factor. hPMSC-conditioned medium activated STAT3 expression in endothelial cells, which was inhibited by neutralizing antibody to interleukin 6 signal transducer (IL6ST) but not to IL6 or leukemia-inhibitory factor. STAT3 siRNA or manganese superoxide dismutase (SOD2) siRNA transfected into endothelial cells inhibited the antiapoptotic effect of conditioned medium. SOD2 was significantly upregulated in endothelial cells by conditioned medium via STAT3 activation that, in turn, was inhibited by IL6ST-neutralizing antibody or STAT3 siRNA. Paracrine factors secreted by hPMSCs support endothelial cell survival. STAT3 activation and SOD2 production protect against oxidative stress-induced endothelial cell damage.
authors.affiliation: Department of Medical Research, Division of High Risk Pregnancy, and Division of Infertility and Human Reproduction, Mackay Memorial Hospital, Taipei, Taiwan.
authors.forename: Shu-Hsiang
authors.initials: SH
authors.lastname: Liu
authors.forename: Jian-Pei
authors.initials: JP
authors.lastname: Huang
authors.forename: Robert Kuo-Kuang
authors.initials: RK
authors.lastname: Lee
authors.forename: Ming-Chao
authors.initials: MC
authors.lastname: Huang
authors.forename: Yi-Hsin
authors.initials: YH
authors.lastname: Wu
authors.forename: Chia-Yu
authors.initials: CY
authors.lastname: Chen
authors.forename: Chie-Pein
authors.initials: CP
authors.lastname: Chen
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects; D017077:Culture Media, Conditioned / Q000494:pharmacology; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000378:metabolism*; D039902:Multipotent Stem Cells / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D019899:Paracrine Communication / Q000502:physiology; D010920:Placenta / Q000166:cytology* / Q000378:metabolism; D011247:Pregnancy; D050796:STAT3 Transcription Factor / Q000187:drug effects / Q000502:physiology*; D013482:Superoxide Dismutase / Q000187:drug effects / Q000378:metabolism*; D000099156:Superoxide Dismutase 2
chemical_list: D017077:Culture Media, Conditioned; D015850:Interleukin-6; D050796:STAT3 Transcription Factor; D013482:Superoxide Dismutase; D000099156:Superoxide Dismutase 2; C494086:STAT3 protein, human