Related Experiment Video
Updated: Apr 16, 2026
Imaging Approaches to Assessments of Toxicological Oxidative Stress Using Genetically-encoded Fluorogenic Sensors
Published on: February 7, 2018
Dopamine D1 and D5 receptors differentially regulate oxidative stress through paraoxonase 2 in kidney cells
1Department of Cardiology, Daping Hospital, The Third Military Medical University , Chongqing , P. R. China.
Background:
The renal dopaminergic system plays an important role in the pathogenesis of hypertension. Dopamine D1-like receptors (D1R and D5R) decrease reactive oxygen species (ROS) production via inhibition of pro-oxidant enzymes such as NADPH oxidase. Paraoxonase 2 (PON2) is also involved in the inhibition of NADPH oxidase activity. Therefore, we tested the hypothesis that D1R and D5R inhibit ROS production by increasing the expression of PON2, including those in membrane microdomains.
Methods And Results:
PON2 colocalized with D1R and D5R in mouse renal proximal tubules (RPTs), human RPT (hRPT) cells, and HEK293 cells heterologously expressing human D1R (HEK-hD1R) or D5R (HEK-hD5R). Fenoldopam, an agonist for both D1R and D5R, increased PON2 co-immunoprecipitation with D1R and D5R in HEK-hD1R and HEK-hD5R cells, respectively. Silencing PON2 increased ROS production and NADPH oxidase activity, and impaired the inhibitory effect of fenoldopam. Fenoldopam increased PON2 protein in both lipid rafts (LRs) and non-LRs in HEK-hD1R cells, but only in non-LRs in HEK-hD5R and hRPT cells. Long-term (hrs) fenoldopam stimulation increased PON2 protein in a time-dependent manner in HEK-hD5R, but not in HEK-hD1R cells. Because the effects of fenoldopam on non-LR and total PON2 expressions were similar in HEK-hD5R and hRPT cells, additional studies were performed to determine the relationship between D5R and PON2. Renal PON2 protein was decreased in D5(-/-) mice. In hRPT cells, silencing D5R decreased PON2 expression and increased ROS production.
Conclusions:
We conclude that D1-like receptors inhibit ROS production by altering PON2 distribution in membrane microdomains in the short-term, and by increasing PON2 expression in the long-term.
Insights
Dopamine D1-like receptors (D1R and D5R) reduce reactive oxygen species (ROS) by modulating Paraoxonase 2 (PON2). This occurs through altered PON2 distribution and increased expression, impacting hypertension pathogenesis.
Area of Science:
- Nephrology
- Molecular Biology
- Cardiovascular Research
Background:
- The renal dopaminergic system is crucial in hypertension development.
- Dopamine D1-like receptors (D1R, D5R) inhibit reactive oxygen species (ROS) production.
- Paraoxonase 2 (PON2) also inhibits ROS by modulating NADPH oxidase.
Purpose of the Study:
- To investigate if D1R and D5R inhibit ROS production by increasing PON2 expression.
- To explore the role of PON2 in membrane microdomains in this process.
Main Methods:
- Utilized mouse renal proximal tubules (RPTs), human RPT (hRPT) cells, and HEK293 cells.
- Employed D1R and D5R agonists (fenoldopam) and gene silencing techniques.
- Analyzed protein localization in lipid rafts and non-lipid rafts.
Main Results:
- PON2 colocalized with D1R and D5R in renal cells and heterologous expression systems.
- Fenoldopam modulated PON2 co-immunoprecipitation and distribution in membrane microdomains.
- Silencing PON2 or D5R increased ROS production and impaired fenoldopam's inhibitory effects.
Conclusions:
- D1-like receptors inhibit ROS production via short-term alteration of PON2 distribution in membrane microdomains.
- Long-term D1-like receptor stimulation increases PON2 expression, contributing to ROS inhibition.
Related Concept Videos
01:29Drugs Affecting Neurotransmitter Synthesis
01:24Peroxisomes
01:46Electron Transport Chain: Complex I and II
ROS generation is regulated and maintained at moderate levels necessary...
01:33Hormonal Regulation