Let-7c-5p Drives Collagen Gene Repression Linking Phenobarbital Teratogenicity to Cleft Palate

Area of Science:

• Developmental biology
• Epigenetics
• Pharmacology

Background:

• Anticonvulsant use during pregnancy, like phenobarbital (PB), poses risks for congenital malformations such as cleft palate (CP).
• MicroRNAs (miRNAs) are crucial regulators of palatogenesis and may be affected by teratogenic drugs.
• Previous studies identified specific miRNA dysregulation in CP patients.

Purpose of the Study:

• To investigate if miRNA dysregulation in CP patients is due to epigenetic changes induced by PB.
• To explore the role of specific miRNAs, like let-7c-5p, in PB-induced teratogenicity and CP development.

Main Methods:

• Treated human embryonic palatal mesenchymal (HEPM) cells with PB and analyzed miRNA expression.
• Compared miRNA profiles in PB-treated cells with those from CP patient tissues.
• Utilized bioinformatic analysis to predict targeted pathways, focusing on collagen genes.
• Validated collagen gene expression using quantitative RT-PCR and performed functional inhibition of let-7c-5p.

Main Results:

• PB treatment altered miRNA expression in HEPM cells, notably downregulating miR-29b-3p and upregulating let-7c-5p, mirroring CP patient data.
• Bioinformatic analysis and validation confirmed collagen fibril organization as a targeted pathway.
• Downregulation of key collagen genes (COL1A2, COL3A1) was observed in both PB-treated cells and CP tissues.
• Inhibition of let-7c-5p reversed PB-induced collagen gene repression.

Conclusions:

• A shared epigenetic regulatory mechanism involving let-7c-5p and collagen genes links PB teratogenicity to CP.
• let-7c-5p acts as a mediator of collagen gene repression in response to PB exposure.
• These findings offer new insights into extracellular matrix remodeling during palatogenesis and PB-induced CP.