Lithium and valproate decrease inositol mass and increase expression of the yeast INO1 and INO2 genes for inositol...

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Bipolar disorder affects 1-2% of the population and is treated with lithium and valproate.
• The therapeutic mechanisms of lithium and valproate remain unclear.
• Identifying drug targets is crucial for improving treatment efficacy.

Purpose of the Study:

• To identify common molecular targets of lithium and valproate.
• To investigate the effects of these drugs on the inositol metabolic pathway.
• To explore the implications for predicting patient response to treatment.

Main Methods:

• Utilized genetic and molecular approaches in Saccharomyces cerevisiae.
• Measured intracellular myo-inositol mass.
• Assessed the expression of inositol biosynthesis genes (INO1, INO2).
• Examined the effects of lithium and valproate on yeast growth and inositol monophosphate synthesis.

Main Results:

• Both lithium and valproate decreased intracellular myo-inositol and increased INO1 and INO2 gene expression.
• The opi1 mutant showed increased resistance to lithium but not valproate.
• Valproate treatment led to decreased inositol monophosphate synthesis, suggesting inhibition of Ino1p.
• This study is the first to show increased expression of inositol biosynthesis genes by both drugs.

Conclusions:

• Lithium and valproate perturb inositol biosynthesis regulation through distinct mechanisms.
• Understanding these effects provides a basis for predicting genetic factors influencing drug response.
• These findings have significant implications for personalized treatment strategies in bipolar disorder.