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Microcystin-LR induces ceramide to regulate PP2A and destabilize cytoskeleton in HEK293 cells

Tan Li1, Linlin Ying, Hao Wang

  • 1Department of Biochemistry and Genetics, School of Medicine, Zhejiang University Hangzhou 310058, China.

Toxicological Sciences : an Official Journal of the Society of Toxicology
|April 24, 2012
PubMed

Insights

Microcystin-LR (MCLR), a potent toxin, induces ceramide generation, which mediates cellular damage including PP2A dysregulation and cytoskeleton destabilization. Ceramide inhibition protects cells from MCLR toxicity.

Area of Science:

  • Environmental toxicology
  • Cellular signaling
  • Biochemistry

Background:

  • Microcystin-LR (MCLR) is a prevalent and toxic cyanotoxin causing environmental harm.
  • MCLR's toxicity is primarily linked to inhibiting protein phosphatase 2A (PP2A), but other cellular processes may be affected.
  • Ceramide, a vital second messenger, regulates cellular functions including PP2A activity and cytoskeleton stability.

Purpose of the Study:

  • To investigate the role of ceramide in mediating Microcystin-LR (MCLR)-induced cellular effects.
  • To determine if ceramide mediates MCLR-induced PP2A dysregulation and cytoskeleton destabilization.
  • To explore ceramide's involvement in MCLR-induced apoptosis and cell detachment.

Main Methods:

  • Utilized human embryonic kidney 293 (HEK293) cells and mouse kidney models.
  • Assessed MCLR-induced ceramide generation.
  • Investigated the effects of MCLR on PP2A activity, protein levels, and subcellular localization.
  • Examined cytoskeleton integrity, cell detachment, and apoptosis.
  • Employed a ceramide synthase inhibitor (desipramine) to assess protective effects.

Main Results:

  • MCLR exposure led to increased ceramide generation in HEK293 cells and mouse kidney.
  • Ceramide was implicated in the MCLR-induced upregulation of PP2A activity and regulatory subunit levels.
  • MCLR caused PP2A/B55α subunit mislocalization to the Golgi apparatus, potentially mediated by ceramide.
  • Ceramide mediated MCLR-induced cytoskeleton destabilization, cell detachment, and apoptosis.
  • Desipramine treatment protected cells against MCLR-induced cellular damage.

Conclusions:

  • Ceramide plays a significant role in mediating Microcystin-LR (MCLR) toxicity.
  • Ceramide is involved in MCLR-induced PP2A dysregulation and cytoskeleton destabilization.
  • Targeting ceramide generation may offer a protective strategy against MCLR poisoning.

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