title: Natural Killer Cells Differentiate Human Adipose-Derived Stem Cells and Modulate Their Adipogenic Potential.
abstract: BACKGROUND
  Natural killer cells are thought to represent more than 30 percent of all lymphocytes within the stromal vascular fraction of lipoaspirates. However, their physiologic interaction with adipocytes and their precursors has never been specifically examined. The authors hypothesized that natural killer cells, by means of cytokine secretion, are capable of promoting the differentiation of adipose-derived stem cells.
  
  
  METHODS
  Human natural killer cells purified from healthy donors' peripheral blood mononuclear cells were activated with a combination of interleukin-2 and anti-CD16 monoclonal antibody; natural killer cell supernatant was collected. Adipose-derived stem cells isolated from raw human lipoaspirates from healthy patients were treated with growth media, growth media with natural killer cell supernatant, adipogenic media, and adipogenic media with natural killer cells supernatant. Flow cytometric analysis was performed on cells using antibodies against B7H1, CD36, CD44, CD34, CD29, and MHC-1. Adipogenic-related gene expression (PPAR-γ, LPL, GPD-1, and aP2) was assessed. Oil Red O staining was performed as a functional assay of adipocyte differentiation and adipogenesis.
  
  
  RESULTS
  Adipose-derived stem cells maintained in growth media with natural killer cell supernatant lost markers of "stemness," including CD44, CD34, and CD29; and expressed markers of differentiation, including B7H1 and MHC-1. Adipose-derived stem cells treated with natural killer cell supernatant accumulated small amounts of lipid after 10 days of natural killer cell supernatant treatment. Adipose-derived stem cells treated with natural killer cell supernatant showed altered expression of adipogenesis-associated genes compared with cells maintained in growth media. Adipose-derived stem cells maintained in adipogenic media with natural killer cell supernatant accumulated less lipid than those cells in adipogenic media alone.
  
  
  CONCLUSIONS
  The authors demonstrate that, through secreted factors, natural killer cells are capable of differentiating adipose-derived stem cells. In cells maintained in adipogenic media, treatment with natural killer cell supernatant modulated adipogenic potential.
authors: Los Angeles, Calif. From the Regenerative Bioengineering and Repair Laboratory, Division of Plastic and Reconstructive Surgery, Department of Surgery, David Geffen School of Medicine at the University of California, Los Angeles; and the Division of Oral Biology and Oral Medicine, The Jane and Jerry Weintraub Center for Reconstructive Biotechnology, University of California, Los Angeles, School of Dentistry.
authors: Kameron S
authors: KS
authors: Rezzadeh
authors: Akishige
authors: A
authors: Hokugo
authors: Anahid
authors: A
authors: Jewett
authors: Anna
authors: A
authors: Kozlowska
authors: Luis Andres
authors: LA
authors: Segovia
authors: Patricia
authors: P
authors: Zuk
authors: Reza
authors: R
authors: Jarrahy
mesh_terms: D017667:Adipocytes / Q000502:physiology*; D050156:Adipogenesis / Q000502:physiology*; D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007694:Killer Cells, Natural / Q000502:physiology*; D015187:Lipectomy; D008875:Middle Aged; D060888:Real-Time Polymerase Chain Reaction; D013234:Stem Cells / Q000502:physiology*; D050151:Subcutaneous Fat / Q000166:cytology
chemical_list: D015415:Biomarkers