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In Vitro and In Vivo Detection of Mitophagy in Human Cells, C. Elegans, and Mice
08:40

In Vitro and In Vivo Detection of Mitophagy in Human Cells, C. Elegans, and Mice

Published on: November 22, 2017

Damage targeted to the mitochondrial interior induces autophagy, cell cycle arrest and, only at high doses, apoptosis

Ausra Sasnauskiene1, Jurgis Kadziauskas, Neringa Vezelyte

  • 1Vilnius University, Vilnius, Lithuania.

Autophagy
|July 3, 2009
PubMed

Insights

Photodynamic treatment targeting the mitochondrial interior in A431 cells induced apoptosis at high doses. Lower doses caused cell cycle inhibition and autophagy, not cell death.

Area of Science:

  • Cell Biology
  • Biochemistry
  • Apoptosis Research

Background:

  • Outer mitochondrial membrane permeabilization is key to apoptosis.
  • Cellular response to inner mitochondrial damage is less understood.

Purpose of the Study:

  • Investigate cellular responses to damage within the mitochondrial interior.
  • Determine the role of reactive oxygen species (ROS) in the mitochondrial inner space.

Main Methods:

  • Utilized photodynamic treatment (PDT) with Safranin O (Safr) to generate singlet oxygen in mitochondria.
  • Applied PDT to epidermoid carcinoma A431 cells.
  • Assessed cell morphology, viability, cell cycle, and apoptosis markers.

Main Results:

  • Low-to-intermediate Safr-PDT doses (up to CD50) inhibited cell cycle and enhanced autophagy without inducing cell death.
  • High Safr-PDT doses (beyond CD70) triggered apoptosis, evidenced by cytochrome c release and caspase-3 activation.
  • Autophagy was enhanced across tested Safr-PDT doses.

Conclusions:

  • Damage to the mitochondrial interior can induce apoptosis via outer membrane permeabilization at sufficient levels.
  • Cellular response to inner mitochondrial damage is dose-dependent, involving cell cycle arrest, autophagy, and apoptosis.
  • Safranin O-mediated PDT is a viable tool for studying mitochondrial-targeted damage and apoptosis induction.

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