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Updated: Mar 11, 2026
Selective Depletion of Microglia from Cerebellar Granule Cell Cultures Using L-leucine Methyl Ester
Published on: July 7, 2015
Selective cytotoxicity of microcystins LR, LW and LF in rat astrocytes
Klara Bulc Rozman1, Damijana Mojca Jurič2, Dušan Šuput1
1Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška cesta 4, Ljubljana, Slovenia.
Abstract:
Microcystins (MCs) comprise a group of cyanobacterial toxins with hepatotoxic, nephrotoxic and, possibly, neurotoxic activity in mammals. In order to understand the development of their neurotoxicity we investigated the toxic effects of MC variants, MC-LR, MC-LW and MC-LF, in astrocytes that play a central role in maintaining brain homeostasis. 24h exposure of cultured rat cortical astrocytes to MCs revealed dose-dependent toxicity of MC-LF and MC-LW, but not of MC-LR, observed by significant reduction in cell number, declined viability monitored by MTT test and an increased percentage of apoptotic cells, confirmed by Annexin-V labelling. The cultured astrocytes expressed organic anion-transporting polypeptides (Oatp) Oatp1a4, Oatp1c1 and Oatp1a5, but not Oatp1b2. Intracellular localisation of MC-LF and MC-LW, proven by anti-Adda primary antibody, demonstrated transport of tested MCs into cultured astrocytes. Acute MC-LW and MC-LF intoxication induced cytoskeletal disruption as seen by the degradation of glial fibrillary acid protein (GFAP), actin and the tubulin network. In this in vitro study, MC-LF and MC-LW, but not MC-LR, are shown to cause the dysfunction of astrocytic homeostatic capabilities, already at low concentrations, suggesting that astrocyte atrophy, with loss of function, could be expected in the brain response to the toxic insult.
Insights
Microcystins (MCs) cause astrocyte damage, impacting brain homeostasis. MC-LF and MC-LW toxins harm astrocytes, unlike MC-LR, suggesting potential neurotoxicity pathways.
Area of Science:
- Neuroscience
- Toxicology
- Cell Biology
Background:
- Microcystins (MCs) are cyanobacterial toxins with known liver and kidney toxicity.
- Potential neurotoxic effects of MCs are not fully understood.
- Astrocytes are crucial for maintaining brain homeostasis.
Purpose of the Study:
- To investigate the neurotoxic effects of MC variants (MC-LR, MC-LW, MC-LF) on astrocytes.
- To determine if MCs are transported into astrocytes and cause cellular damage.
- To understand the role of astrocytes in MC-induced neurotoxicity.
Main Methods:
- Primary rat cortical astrocyte cultures were exposed to MC variants.
- Cell viability (MTT assay), apoptosis (Annexin-V), and cell number were assessed.
- Expression of organic anion-transporting polypeptides (Oatp) was analyzed.
- Intracellular MC localization was confirmed using an anti-Adda antibody.
- Cytoskeletal proteins (GFAP, actin, tubulin) were evaluated for degradation.
Main Results:
- MC-LF and MC-LW exhibited dose-dependent toxicity, reducing cell viability and increasing apoptosis.
- MC-LR did not show significant toxicity in astrocytes.
- Astrocytes expressed Oatp1a4, Oatp1c1, and Oatp1a5, facilitating MC-LF and MC-LW uptake.
- MC-LW and MC-LF induced cytoskeletal disruption, degrading GFAP, actin, and tubulin.
- Astrocytic homeostatic functions were impaired by MC-LF and MC-LW at low concentrations.
Conclusions:
- MC-LF and MC-LW, but not MC-LR, are toxic to astrocytes in vitro.
- These MC variants are transported into astrocytes, leading to cellular dysfunction and cytoskeletal damage.
- Astrocyte impairment by MCs may contribute to neurotoxicity and brain homeostasis disruption.
