Short-term memory of danger signals or environmental stimuli in mesenchymal stem cells: implications for therapeutic potential

Cell Mol Immunol. 2016 May;13(3):369-78. doi: 10.1038/cmi.2015.11. Epub 2015 Mar 16.

Abstract

Mesenchymal stem/stromal cells (MSCs) possess some characteristics of immune cells, including a pro-inflammatory phenotype, an immunosuppressive phenotype, antibacterial properties and the expression of Toll-like receptor proteins. Here we show that, similar to immune cells, MSCs retain information from danger signals or environmental stimuli for a period of time. When treated with the pro-inflammatory factors lipopolysaccharide (LPS) or tumor necrosis factor-α (TNF-α), MSCs display increased expression of IL-6, IL-8 and MCP-1. Following re-plating and several rounds of cell division in the absence of stimulating factors, the expression of IL-6, IL-8 and MCP-1 remained higher than in untreated cells for over 7 days. A spike in cytokine secretion occurred when cells were exposed to a second round of stimulation. We primed MSCs with LPS and LPS-primed MSCs had better therapeutic efficacy at promoting skin flap survival in a diabetic rat model than did unprimed MSCs. Finally, we found that several microRNAs, including miR146a, miR150 and miR155, along with the modification of DNA by 5-hydroxymethylcytosine (5hmC), mediate the MSC response to LPS and TNF-α stimulation. Collectively, our data suggest that MSCs have a short-term memory of environmental signals, which may impact their therapeutic potential.

MeSH terms

  • 5-Methylcytosine / analogs & derivatives
  • 5-Methylcytosine / metabolism
  • Adipose Tissue / cytology
  • Animals
  • Cell Differentiation / drug effects
  • Cell Proliferation / drug effects
  • Cell Shape / drug effects
  • Chemokine CCL2 / metabolism
  • DNA Methylation / drug effects
  • Diabetes Mellitus, Experimental / pathology
  • Enzyme-Linked Immunosorbent Assay
  • Immunologic Memory* / drug effects
  • Immunophenotyping
  • Interleukin-6 / metabolism
  • Interleukin-8 / metabolism
  • Lipopolysaccharides / pharmacology
  • Male
  • Mesenchymal Stem Cell Transplantation*
  • Mesenchymal Stem Cells / cytology
  • Mesenchymal Stem Cells / drug effects
  • Mesenchymal Stem Cells / metabolism*
  • MicroRNAs / genetics
  • MicroRNAs / metabolism
  • Rats, Wistar
  • Real-Time Polymerase Chain Reaction
  • Signal Transduction* / drug effects
  • Surgical Flaps / physiology
  • Tissue Survival / drug effects
  • Tumor Necrosis Factor-alpha / pharmacology

Substances

  • Chemokine CCL2
  • Interleukin-6
  • Interleukin-8
  • Lipopolysaccharides
  • MicroRNAs
  • Tumor Necrosis Factor-alpha
  • 5-hydroxymethylcytosine
  • 5-Methylcytosine