Catecholamines regulate the activity, secretion, and synthesis of renalase

Area of Science:

• Biochemistry
• Physiology
• Nephrology

Background:

• Renalase is a novel secreted amine oxidase that metabolizes circulating catecholamines.
• Parenteral administration of renalase reduces blood pressure, heart rate, and cardiac contractility.
• Reduced renalase plasma levels are observed in chronic kidney disease patients, but its endogenous role is unknown.

Purpose of the Study:

• To investigate the endogenous role of renalase in catecholamine regulation.
• To understand the activation mechanism of renalase under physiological conditions.

Main Methods:

• Assessed renalase amine oxidase activity in response to epinephrine surges in vivo and in vitro.
• Measured hemodynamic changes in rats following epinephrine administration.
• Investigated renalase gene expression in cultured cells exposed to dopamine.
• Examined prorenalase activation in rats with chronic kidney disease.

Main Results:

• Circulating renalase (prorenalase) is inactive basally but rapidly activates upon epinephrine surge.
• Activation increases renalase activity significantly within seconds, sustained for over an hour.
• Epinephrine surge increases plasma renalase concentration and upregulates renalase gene expression.
• Prorenalase activation is abnormal in rats with chronic kidney disease.

Conclusions:

• Identifies a novel catecholamine regulatory mechanism: excess catecholamines activate prorenalase, an inactive precursor, into active renalase.
• Catecholamine surges not only activate but also promote renalase secretion and synthesis.
• Renalase replacement therapy is a promising therapeutic strategy for chronic kidney disease due to its role in catecholamine metabolism.