RNA-binding proteins regulate aldosterone homeostasis in human steroidogenic cells

Area of Science:

• Endocrinology
• Molecular Biology
• Genomics

Background:

• Aldosterone, regulated by Angiotensin II (AngII), is crucial for blood pressure control.
• Precise regulation of AngII-induced gene expression kinetics in adrenocortical cells remains incompletely understood.
• The roles of RNA-binding proteins (RBPs) and RNA decay in this process are largely unknown.

Purpose of the Study:

• To investigate the regulatory contribution of RBPs and RNA decay to AngII-induced gene expression kinetics in aldosterone production.
• To identify specific RBPs and RNA decay factors influencing aldosterone synthesis.
• To elucidate the mechanisms controlling the timing of steroidogenic gene expression.

Main Methods:

• High-resolution RNA-sequencing (RNA-seq) time course analysis of AngII stimulation.
• 4-thiouridine pulse labeling in H295R human steroidogenic cells.
• Candidate screening for RBPs and RNA decay factors impacting aldosterone production.
• Validation in primary human adrenocortical cells.

Main Results:

• Identified twelve temporally distinct gene expression responses to AngII, including mRNAs for cAMP signaling and steroidogenic enzymes.
• Observed coordinated increases in both synthesis and decay for many AngII-responsive mRNAs.
• Identified RBPs and RNA decay factors that modulate AngII-stimulated aldosterone production, with BTG2 acting as a repressor.

Conclusions:

• Coordinated increases in transcription and decay facilitate transcriptomic changes for a pro-steroidogenic program.
• An incoherent feedforward loop involving BTG2 actively resolves to prevent aldosterone overproduction.
• RNA decay mechanisms play a critical role in fine-tuning aldosterone homeostasis.