title: Visible red and infrared light alters gene expression in human marrow stromal fibroblast cells.
abstract: OBJECTIVE
  This study tested whether or not gene expression in human marrow stromal fibroblast (MSF) cells depends on light wavelength and energy density.
  
  
  METHODS
  Primary cultures of isolated human bone marrow stem cells (hBMSC) were exposed to visible red (VR, 633 nm) and infrared (IR, 830 nm) radiation wavelengths from a light emitting diode (LED) over a range of energy densities (0.5, 1.0, 1.5, and 2.0 Joules/cm2) Cultured cells were assayed for cell proliferation, osteogenic potential, adipogenesis, mRNA and protein content. mRNA was analyzed by microarray and compared among different wavelengths and energy densities. Mesenchymal and epithelial cell responses were compared to determine whether responses were cell type specific. Protein array analysis was used to further analyze key pathways identified by microarrays.
  
  
  RESULTS
  Different wavelengths and energy densities produced unique sets of genes identified by microarray analysis. Pathway analysis pointed to TGF-beta 1 in the visible red and Akt 1 in the infrared wavelengths as key pathways to study. TGF-beta protein arrays suggested switching from canonical to non-canonical TGF-beta pathways with increases to longer IR wavelengths. Microarrays suggest RANKL and MMP 10 followed IR energy density dose-response curves. Epithelial and mesenchymal cells respond differently to stimulation by light suggesting cell type-specific response is possible.
  
  
  CONCLUSIONS
  These studies demonstrate differential gene expression with different wavelengths, energy densities and cell types. These differences in gene expression have the potential to be exploited for therapeutic purposes and can help explain contradictory results in the literature when wavelengths, energy densities and cell types differ.
authors: Center for Craniofacial Molecular Biology, Ostrow School of Dentistry, University of Southern California, Los Angeles, CA, USA; Department of Orthodontics, School of Stomatology, Shandong University, Jinan, China.
authors: J
authors: J
authors: Guo
authors: Q
authors: Q
authors: Wang
authors: D
authors: D
authors: Wai
authors: Q Z
authors: QZ
authors: Zhang
authors: S H
authors: SH
authors: Shi
authors: A D
authors: AD
authors: Le
authors: S T
authors: ST
authors: Shi
authors: S L-K
authors: SL
authors: Yen
mesh_terms: D050156:Adipogenesis / Q000528:radiation effects; D018929:Cell Culture Techniques; D002460:Cell Line; D049109:Cell Proliferation / Q000528:radiation effects; D002478:Cells, Cultured; D003116:Color; D004307:Dose-Response Relationship, Radiation; D004847:Epithelial Cells / Q000528:radiation effects; D005347:Fibroblasts / Q000528:radiation effects*; D015870:Gene Expression / Q000528:radiation effects*; D020869:Gene Expression Profiling; D006801:Humans; D007259:Infrared Rays; D015603:Keratinocytes / Q000528:radiation effects; D008027:Light; D053506:Matrix Metalloproteinase 10 / Q000528:radiation effects; D059630:Mesenchymal Stem Cells / Q000502:physiology / Q000528:radiation effects*; D046228:Microarray Analysis; D010012:Osteogenesis / Q000528:radiation effects; D051057:Proto-Oncogene Proteins c-akt / Q000528:radiation effects; D053245:RANK Ligand / Q000528:radiation effects; D012333:RNA, Messenger / Q000528:radiation effects; D011829:Radiation Dosage; D015398:Signal Transduction / Q000528:radiation effects; D016212:Transforming Growth Factor beta / Q000528:radiation effects
chemical_list: D053245:RANK Ligand; D012333:RNA, Messenger; C505688:TNFSF11 protein, human; D016212:Transforming Growth Factor beta; C494918:AKT1 protein, human; D051057:Proto-Oncogene Proteins c-akt; C511770:MMP10 protein, human; D053506:Matrix Metalloproteinase 10
keywords: Akt 1; OPG; RANKL; TGF-beta; infrared; low-level laser treatment; mesenchymal stem cell; microarray; protein array