title: Down-regulation of the autophagy gene, ATG7, protects bone marrow-derived mesenchymal stem cells from stressful conditions.
abstract: BACKGROUND
  Mesenchymal stem cells (MSCs) are valuable for cell-based therapy. However, their application is limited owing to their low survival rate when exposed to stressful conditions. Autophagy, the process by which cells recycle the cytoplasm and dispose of defective organelles, is activated by stress stimuli to adapt, tolerate adverse conditions, or trigger the apoptotic machinery. This study aimed to determine whether regulation of autophagy would affect the survival of MSCs under stress conditions.
  
  
  METHODS
  Autophagy was induced in bone marrow-derived MSCs (BM-MSCs) by rapamycin, and was inhibited via shRNA-mediated knockdown of the autophagy specific gene, ATG7. ATG7 expression in BM-MSCs was evaluated by reverse transcription polymerase chain reaction (RT-PCR), western blot, and quantitative PCR (qPCR). Cells were then exposed to harsh microenvironments, and a water-soluble tetrazolium salt (WST)-1 assay was performed to determine the cytotoxic effects of the stressful conditions on cells.
  
  
  RESULTS
  Of 4 specific ATG7-inhibitor clones analyzed, only shRNA clone 3 decreased ATG7 expression. Under normal conditions, the induction of autophagy slightly increased the viability of MSCs while autophagy inhibition decreased their viability. However, under stressful conditions such as hypoxia, serum deprivation, and oxidative stress, the induction of autophagy resulted in cell death, while its inhibition potentiated MSCs to withstand the stress conditions. The viability of autophagy-suppressed MSCs was significantly higher than that of relevant controls (P<0.05, P<0.01 and P<0.001).
  
  
  CONCLUSIONS
  Autophagy modulation in MSCs can be proposed as a new strategy to improve their survival rate in stressful microenvironments.
authors.affiliation: Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran.
authors.forename: Sedigheh
authors.initials: S
authors.lastname: Molaei
authors.affiliation: Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran.
authors.forename: Mehryar Habibi
authors.initials: MH
authors.lastname: Roudkenar
authors.affiliation: Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Amiri
authors.affiliation: Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran.
authors.forename: Mozhgan Dehghan
authors.initials: MD
authors.lastname: Harati
authors.affiliation: Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran.
authors.forename: Marzie
authors.initials: M
authors.lastname: Bahadori
authors.affiliation: Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Jaleh
authors.affiliation: Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran.
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Jalili
authors.affiliation: Department of Anatomical Sciences, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Amaneh
authors.initials: A
authors.lastname: Mohammadi Roushandeh
keywords: Autophagy; Cell survival; Mesenchymal stem cells; Oxidative stress; shRNA