Photodynamic activation as a molecular switch to promote osteoblast cell differentiation via AP-1 activation.
In photodynamic therapy (PDT), cells are impregnated with a photosensitizing agent that is activated by light irradiation, thereby photochemically generating reactive oxygen species (ROS). The amounts of ROS produced depends on the PDT dose and the nature of the photosensitizer. Although high levels of ROS are cytotoxic, at physiological levels they play a key role as second messengers in cellular signaling pathways, pluripotency, and differentiation of stem cells. To investigate further the use of photochemically triggered manipulation of such pathways, we exposed mouse osteoblast precursor cells and rat primary mesenchymal stromal cells to low-dose PDT. Our results demonstrate that low-dose PDT can promote osteoblast differentiation via the activation of activator protein-1 (AP-1). Although PDT has been used primarily as an anti-cancer therapy, the use of light as a photochemical "molecular switch" to promote differentiation should expand the utility of this method in basic research and clinical applications.
1] Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, USA, 40 Blossom Street, Boston, MA 02114, USA [2] Department of Medical Engineering, National Defense Medical College, Japan, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan.
Toshihiro
T
Kushibiki
Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, USA, 40 Blossom Street, Boston, MA 02114, USA.
Yupeng
Y
Tu
Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, USA, 40 Blossom Street, Boston, MA 02114, USA.
Adnan O
AO
Abu-Yousif
Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, USA, 40 Blossom Street, Boston, MA 02114, USA.
Tayyaba
T
Hasan
D000622:Aminolevulinic Acid / Q000494:pharmacology; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects* / Q000528:radiation effects; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D002478:Cells, Cultured; D007834:Lasers; D059630:Mesenchymal Stem Cells / Q000166:cytology; D051379:Mice; D008928:Mitochondria / Q000378:metabolism; D008958:Models, Molecular; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism; D017319:Photosensitizing Agents / Q000494:pharmacology*; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000378:metabolism*
D017319:Photosensitizing Agents; D017382:Reactive Oxygen Species; D018808:Transcription Factor AP-1; D000622:Aminolevulinic Acid