Oxidative stress increases A1 adenosine receptor expression by activating nuclear factor kappa B

Area of Science:

• Biochemistry
• Molecular Biology
• Pharmacology

Background:

• The A1 adenosine receptor (A1AR) plays a cytoprotective role against reactive oxygen species (ROS).
• Modulating A1AR expression can influence its cytoprotective function.
• Understanding the regulation of A1AR expression under oxidative stress is crucial.

Purpose of the Study:

• To investigate whether ROS can increase A1AR expression.
• To elucidate the molecular mechanisms underlying ROS-induced A1AR upregulation.
• To determine if increased A1AR expression enhances cytoprotection against ROS.

Main Methods:

• Incubation of DDT1MF-2 smooth muscle cells with ROS-generating agents (cisplatin, H2O2).
• Assessment of A1AR expression using Western blotting and promoter activity assays.
• Electrophoretic mobility shift assays (EMSA) and Western blotting to detect transcription factor activation (NF-κB, AP-1).
• Inhibition studies using ROS scavengers and NF-κB inhibitors.
• Measurement of lipid peroxidation to assess cytoprotection.

Main Results:

• Cisplatin and H2O2 treatment increased A1AR expression in DDT1MF-2 cells.
• H2O2-induced A1AR increase was partially mediated by ROS, as shown by catalase treatment.
• Inhibition of nuclear factor kappa B (NF-κB) abrogated cisplatin-induced A1AR upregulation.
• Cisplatin promoted NF-κB nuclear translocation, and a functional NF-κB binding site was identified in the A1AR promoter.
• A1AR activation reduced cisplatin-induced lipid peroxidation, indicating enhanced cytoprotection.

Conclusions:

• ROS can upregulate A1AR expression through NF-κB activation.
• Increased A1AR expression enhances the cytoprotective effects of adenosine against ROS-induced damage.
• This mechanism represents a novel pathway for cellular defense against oxidative stress.