Microcystin-LR-Triggered Neuronal Toxicity in Whitefish Does Not Involve MiR124-3p

Area of Science:

• Environmental toxicology
• Neuroscience
• Molecular biology

Background:

• Microcystin-LR (MC-LR) is a cyanotoxin with known hepatotoxicity and suspected neurotoxicity.
• MicroRNA signaling, particularly involving microRNA-124-3p (MiR124-3p) and glial fibrillary acidic protein (GFAP), is implicated in astrocyte reactivity.

Purpose of the Study:

• To investigate the role of MiR124-3p in MC-LR-induced neurotoxicity in whitefish (Coregonus lavaretus).
• To examine the potential interaction between MiR124-3p and GFAP mRNA expression following MC-LR exposure.

Main Methods:

• Quantitative PCR (qPCR) to measure gfap mRNA and MiR124-3p levels in whitefish midbrain and blood plasma.
• Exposure of juvenile whitefish to subacute doses of MC-LR for 28 days.
• Double luciferase gene reporter assay to confirm MiR124-3p's regulatory effect on gfap mRNA.

Main Results:

• A marginal, transient up-regulation of gfap mRNA was observed on day 7 of MC-LR exposure.
• No significant changes in MiR124-3p levels were detected in the midbrain or blood plasma throughout the 28-day exposure period.
• The luciferase assay demonstrated that MiR124-3p does not directly regulate gfap mRNA.

Conclusions:

• MC-LR exposure can induce neuronal toxicity in whitefish, evidenced by changes in gfap expression.
• The neurotoxic effects of MC-LR in this model do not appear to be mediated by the MiR124-3p pathway targeting GFAP.