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Activation of Apoptosis by Cytoplasmic Microinjection of Cytochrome c
07:42

Activation of Apoptosis by Cytoplasmic Microinjection of Cytochrome c

Published on: June 29, 2011

The cyanobacterial toxin, microcystin-LR, can induce apoptosis in a variety of cell types

C M McDermott1, C W Nho, W Howard

  • 1Department of Biology and Microbiology, Halsey Science Center, University of Wisconsin Oshkosh, 54901, USA.

Toxicon : Official Journal of the International Society on Toxinology
|December 5, 1998
PubMed

Insights

Microcystins (MCYST), harmful cyanobacterial toxins, induce apoptosis, programmed cell death, in various mammalian cells. This cellular damage occurs through specific morphological and biochemical changes following MCYST exposure.

Area of Science:

  • Environmental Toxicology
  • Cell Biology
  • Biochemistry

Background:

  • Cyanobacterial toxins, particularly microcystins (MCYST), are prevalent in eutrophied waters globally.
  • MCYST inhibits protein phosphatases 1 and 2A, leading to hepatocyte damage via cytoskeletal protein hyperphosphorylation.
  • Acute intoxication in humans and animals from MCYST exposure is a documented concern.

Purpose of the Study:

  • To investigate the induction of apoptosis by microcystins (MCYST) in various mammalian cell types.
  • To characterize the morphological and biochemical changes associated with MCYST-induced apoptosis.

Main Methods:

  • Primary rat hepatocytes, human fibroblasts, human endothelial cells, human epithelial cells, and rat promyelocytes were utilized.
  • Cells were treated with MCYST at varying concentrations (0.8 microM and 100 microM).
  • Morphological changes (membrane blebbing, shrinkage, chromatin condensation) and biochemical markers (DNA fragmentation) of apoptosis were assessed.

Main Results:

  • Hepatocytes exhibited early apoptotic changes within 30 minutes of MCYST exposure (0.8 microM).
  • Other cell types demonstrated similar apoptotic morphology but required longer exposure times to MCYST (100 microM).
  • DNA fragmentation and ladder formation, indicative of apoptosis, were observed in most MCYST-treated cell types.

Conclusions:

  • Microcystins (MCYST) induce apoptosis in a diverse range of mammalian cell types.
  • MCYST triggers characteristic morphological and biochemical hallmarks of programmed cell death.
  • These findings highlight the cytotoxic potential of MCYST beyond hepatocyte damage.

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