The Relationship between the Bcl-2/Bax Proteins and the Mitochondria-Mediated Apoptosis Pathway in the Differentiation of Adipose-Derived Stromal Cells into Neurons

PLoS One. 2016 Oct 5;11(10):e0163327. doi: 10.1371/journal.pone.0163327. eCollection 2016.

Abstract

Our objective is to study the relationship between the regulatory proteins Bcl-2/Bax and mitochondria-mediated apoptosis during the differentiation of adipose-derived stromal cells (ADSCs) into neurons. Immunocytochemistry and western blotting showed that the cells weakly expressed neuron-specific enolase (NSE) in the non-induced group and expressed NSE more strongly in the groups induced for 1 h, 3 h, 5 h and 8 h. NSE expression peaked at 5 h (P < 0.05), although there was no significant difference between 5 and 8 h (P > 0.05). Bcl-2 expression gradually decreased over time in the non-induced group (P < 0.05). However, Bax, caspase-9, Cyt-c and caspase-3 expression gradually increased and peaked at 8 h (P < 0.05). Transmission electron microscopy revealed karyopyknosis, chromatin edge setting, mitochondria swelling and cavitation in cells at 5 h, and the mitochondrial membrane potential decreased over time, as demonstrated by laser scanning confocal microscopy. After a 5 h induction, cells differentiated into typical neurons and expressed Bcl-2, which inhibited apoptosis. Bax showed a strong apoptosis-promoting capacity, leading to changes in the mitochondrial membrane potential and structure, and then triggered the caspase-independent apoptotic response through the mitochondrial pathway. At the same time, Cyt-c was directly or indirectly released from the mitochondria to the cytoplasm to trigger the caspase-dependent apoptotic response through the mitochondrial pathway. Therefore, Bcl-2/Bax play an important role in regulating caspase-dependent and caspase-independent apoptosis mediated by the mitochondrial pathway during the differentiation of ADSCs into neurons.

MeSH terms

  • Adipose Tissue / cytology
  • Apoptosis*
  • Caspase 3 / metabolism
  • Caspase 9 / metabolism
  • Cell Differentiation
  • Cells, Cultured
  • Cytochromes c / metabolism
  • Humans
  • Immunohistochemistry
  • Membrane Potential, Mitochondrial
  • Microscopy, Confocal
  • Microscopy, Electron, Transmission
  • Mitochondria / metabolism*
  • Mitochondria / ultrastructure
  • Neurons / cytology*
  • Neurons / metabolism
  • Proto-Oncogene Proteins c-bcl-2 / metabolism*
  • Stromal Cells / cytology*
  • Stromal Cells / metabolism
  • bcl-2-Associated X Protein / metabolism*

Substances

  • Proto-Oncogene Proteins c-bcl-2
  • bcl-2-Associated X Protein
  • Cytochromes c
  • Caspase 3
  • Caspase 9

Grants and funding

There was no funding that supported our work.