Transcriptome Analysis of Human Reninomas as an Approach to Understanding Juxtaglomerular Cell Biology

Area of Science:

• Nephrology
• Endocrinology
• Cell Biology

Background:

• Renin is crucial for blood pressure regulation, produced by kidney juxtaglomerular cells.
• Juxtaglomerular cells can arise from smooth muscle cells, but their origin and plasticity are unclear due to dedifferentiation outside the kidney.

Purpose of the Study:

• To investigate the developmental origin and phenotypic plasticity of juxtaglomerular cells.
• To identify novel regulators of renin production and juxtaglomerular cell phenotype.

Main Methods:

• RNA expression analysis of human renin-producing tumors (reninomas).
• In situ hybridization in mouse kidneys (neonatal, adult, and captopril-treated).
• Ligand screening using (pro)renin-synthesizing As4.1 cells exposed to secreted factors.

Main Results:

• Platelet-derived growth factor B (PDGF-B) significantly reduced (pro)renin levels and renin gene expression in As4.1 cells.
• PDGF-B exposure induced phenotypic changes in As4.1 cells, including altered shape and gene expression (downregulated α-smooth muscle actin, upregulated interleukin-6).
• 36 new genes were identified that characterize renin-producing cells.

Conclusions:

• Platelet-derived growth factor B is a novel regulator of renin-synthesizing cells, impacting both renin production and cell phenotype.
• The findings suggest a potential phenotypic shift from myoendocrine to inflammatory characteristics in response to PDGF-B.
• This research provides new insights into the plasticity and regulation of juxtaglomerular cells.