Transcriptomic Changes in Endothelial Cells Triggered by Na,K-ATPase Inhibition: A Search for Upstream Na⁺_i/K⁺_i...

Area of Science:

• Cellular Biology
• Molecular Biology
• Genetics

Background:

• Intracellular calcium (Ca²⁺) elevation typically modulates gene expression through calmodulin-mediated pathways.
• Recent findings suggest a Ca²⁺-independent mechanism linking intracellular sodium ([Na⁺]ᵢ) and potassium ([K⁺]ᵢ) ratios to gene expression.

Purpose of the Study:

• To identify upstream genes sensitive to the intracellular sodium-to-potassium ([Na⁺]ᵢ/[K⁺]ᵢ) ratio.
• To investigate a novel excitation-transcription coupling mechanism mediated by [Na⁺]ᵢ/[K⁺]ᵢ.

Main Methods:

• Transcriptomic analysis of human umbilical vein endothelial cells (HUVECs).
• Inhibition of Na,K-ATPase using ouabain.
• Exposure to potassium (K⁺)-free medium.

Main Results:

• The intracellular [Na⁺]ᵢ/[K⁺]ᵢ ratio influences gene expression independently of Ca²⁺.
• Key components identified include microRNAs, transcription factors, and immune/inflammatory proteins.
• The FOS gene and G-quadruplex structures were highlighted for their potential role in [Na⁺]ᵢ/[K⁺]ᵢ-sensitive transcription regulation.

Conclusions:

• A novel Na⁺ᵢ/K⁺ᵢ-mediated excitation-transcription coupling mechanism exists.
• This pathway involves specific gene regulatory elements like G-quadruplexes.
• Further research is needed to fully elucidate this transcription regulation mechanism.