Dissecting hypertonicity- and NFAT5-dependent gene expression programs in mpkCCD cells

Area of Science:

• Renal physiology and molecular biology
• Kidney gene expression regulation

Background:

• The corticomedullary osmotic gradient influences kidney gene expression.
• Nuclear factor of activated T-cells 5 (NFAT5) is activated by hypertonicity and regulates osmoprotective genes.
• NFAT5's role in basal gene regulation is not fully understood.

Purpose of the Study:

• To investigate the role of NFAT5 in gene regulation under both isotonic and hypertonic conditions.
• To identify genes regulated by NFAT5 in kidney cells.
• To compare in vitro findings with in vivo mouse models.

Main Methods:

• Utilized murine principal kidney cortical collecting duct (mpkCCD) cells.
• Induced functional deletion of NFAT5 in mpkCCD cells.
• Performed gene expression profiling under isotonic and hypertonic conditions.
• Compared transcriptomes with gene expression data from NFAT5 knockout mice.

Main Results:

• Hypertonic stress caused significant transcriptional changes in control cells, altered in NFAT5-deficient cells.
• A partial overlap was observed between hypertonicity-associated, NFAT5-dependent gene expression in vitro and in vivo.
• Known NFAT5 target genes, such as Aqp2 and Ranbp3l, were downregulated in NFAT5-deficient conditions.

Conclusions:

• NFAT5 plays a role in regulating gene expression under both basal and hypertonic conditions.
• mpkCCD cells serve as a valuable complementary model for studying NFAT5-mediated gene regulation in vitro.
• Findings provide insights into the spatial gene expression patterns in the renal medulla.