Rapid acting antidepressants in the mTOR pathway: Current evidence

Area of Science:

• Neuroscience
• Pharmacology
• Molecular Biology

Background:

• Major depressive disorder (MDD) poses a significant societal burden, with current treatments often exhibiting slow onset and low response rates.
• Conventional MDD therapies primarily target monoaminergic mechanisms, limiting their efficacy and prolonging patient distress.

Purpose of the Study:

• To review preclinical and clinical evidence for fast-acting antidepressants modulating the mammalian target of rapamycin (mTOR) pathway in MDD.
• To explore the mechanistic basis of rapid antidepressant effects mediated by mTOR pathway activation.

Main Methods:

• Literature review of preclinical studies investigating mTOR pathway modulation for antidepressant effects.
• Analysis of clinical trial data for drugs targeting the mTOR pathway in MDD patients.
• Examination of molecular mechanisms, including receptor interactions and downstream effects on synaptic plasticity.

Main Results:

• Modulating the mTOR pathway enhances synaptic protein synthesis, synaptogenesis, and spine remodeling, contributing to rapid antidepressant effects.
• Fast-acting antidepressants target various receptors (NMDA, AMPA, m1ACh, mGluR2/3, GluN2B) to boost mTOR function.
• Despite promising mechanisms, some mTOR-targeting drugs have faced challenges in late-stage clinical trials.

Conclusions:

• Modulating the mTOR pathway presents a viable strategy for developing rapid-onset antidepressants for MDD.
• Challenges remain in the clinical translation of mTOR-targeting therapies, evidenced by trial failures.
• The recent approval of esketamine highlights the potential for novel antidepressant mechanisms, with mTOR pathway modulators showing promise in the drug discovery pipeline.