Carbonyl reductases from Daphnia are regulated by redox cycling compounds. (20th June 2018)

• Record Type: Journal Article
• Authors: Ebert, Bettina; Ebert, Dieter; Koebsch, Katrin; Maser, Edmund; Kisiela, Michael
• Is Part Of: FEBS journal. Volume 285:Number 15(2018)
• Page Start: 2869
• Page End: 2887
• Publication Date: 2018-06-20
• Subjects: catalytic activity -- Daphnia magna -- Daphnia pulex -- gene expression -- menadione -- oxidative stress -- paraquat -- redox cycling agents -- Short‐chain dehydrogenase/reductase (SDR); Biochemistry -- Periodicals; Molecular biology -- Periodicals; Pathology, Molecular -- Periodicals; 572
• DOI: 10.1111/febs.14578
• Languages: English
• ISSNs: 1742-464X

Abstract

Abstract : Oxidative stress is a major source of reactive carbonyl compounds that can damage cellular macromolecules, leading to so‐called carbonyl stress. Aside from endogenously formed carbonyls, including highly reactive short‐chain aldehydes and diketones, air pollutants derived from diesel exhaust like 9, 10‐phenanthrenequinone (PQ) can amplify oxidative stress by redox cycling, causing tissue damage. Carbonyl reductases (CRs), which are inducible in response to ROS, represent a fundamental enzymatic defense mechanism against oxidative stress. While commonly two carbonyl reductases (CBR1 and CBR3) are found in mammalian genomes, invertebrate model organisms like Drosophila melanogaster express no CR but a functional homolog to human CBR1, termed sniffer. The microcrustacean Daphnia is an ideal model organism to investigate the function of CRs because of its unique equipment with even four copies of the CR gene (CR1, CR2, CR3, CR4) in addition to one sniffer gene. Cloning and catalytic characterization of two carbonyl reductases CR1 and CR3 from D. magna and D. pulex arenata revealed that both proteins reductively metabolize aromatic dicarbonyls (e.g., menadione, PQ) and aliphatic α‐diketones (e.g., 2, 3‐hexanedione), while sugar‐derived aldehydes (methylglyoxal, glyoxal) and lipid peroxidation products such as acrolein and butanal were poor substrates, indicating no physiological function in the metabolism of short‐chain aldehydes. Treatment of D. magna with redox cyclers like menadione and the pesticide paraquat led to an upregulation of CR1 and CR3 mRNA, suggesting a role in oxidative stress defense. Further studies are needed to investigate their potential to serve as novel biomarkers for oxidative stress in Daphnia . Abstract : Daphnia carbonyl reductases are regulated by redox cycling compounds (9, 10‐phenanthrenequinone, menadione). By mediating the NADH‐dependent reduction of several quinones and aliphatic diketones, they possibly function as a protective mechanism against oxidative stress.