TSC complex decrease the expression of mTOR by regulated miR-199b-3p

Area of Science:

• Molecular Biology
• Genetics
• Cellular Signaling

Background:

• The tuberous sclerosis complex (TSC) is a rare genetic disorder caused by mutations in TSC1 or TSC2 genes.
• The TSC complex (TSC1/TSC2) is a critical negative regulator of the mechanistic target of rapamycin complex 1 (mTORC1).
• Dysregulation of mTOR signaling is implicated in various diseases, including TSC.

Purpose of the Study:

• To investigate the molecular mechanisms underlying TSC caused by novel genetic variations in TSC1 and TSC2.
• To explore the role of microRNA-199b-3p (miR-199b-3p) in TSC pathogenesis and mTOR signaling.
• To identify potential therapeutic targets for TSC.

Main Methods:

• Genetic analysis of patients with TSC to identify variations in TSC1 and TSC2.
• Cellular assays to assess the impact of identified mutations on TSC complex formation and stability.
• Quantitative real-time PCR (qRT-PCR) to measure miR-199b-3p expression levels.
• Western blotting to evaluate the expression and activation of mTOR, mTORC1, and mTORC2.

Main Results:

• Identified a novel de novo TSC2 variation (c.1113delG, p.Q371fs) alongside a reported TSC1 variation (c.2509_2512del, p.N837fs).
• Observed decreased TSC complex formation correlating with reduced miR-199b-3p expression in affected cells.
• Demonstrated that reduced miR-199b-3p expression leads to increased mTOR expression and activation of mTORC1 and mTORC2.
• Showed that supplementing miR-199b-3p reverses the increased mTOR expression and mTORC1/mTORC2 activation.

Conclusions:

• Genetic variations in TSC1 or TSC2 disrupt TSC complex formation, contributing to TSC disease.
• miR-199b-3p plays a crucial role in regulating mTOR signaling pathways.
• miR-199b-3p represents a potential therapeutic target for managing TSC and related disorders.