Rational Redesign of Monoamine Oxidase A into a Dehydrogenase to Probe ROS in Cardiac Aging

• Authors: Luca G Iacovino, University of Pavia; Nicola Manzella, Université de Toulouse; Jessica Resta, Université de Toulouse; Maria Antonietta Vanoni, University of Milan; Laura Rotilio, Univ Bari Aldo Moro; Leonardo Pisani, Emory University; Dale Edmondson, Emory University; Angelo Parini, Université de Toulouse; Andrea Mattevi, University of Pavia; Jeanne Mialet-Perez, Université de Toulouse; Claudia Binda, University of Pavia
• Journal Title: ACS CHEMICAL BIOLOGY
• Volume: Volume 15, Number 7
• Publisher: AMER CHEMICAL SOC | 2020-07-17, Pages 1795-1800
• Type of Work: Article | Post-print: After Peer Review
• Publisher DOI: http://doi.org/10.1021/acschembio.0c00366
• Subjects: Health Sciences, Pharmacy; Chemistry, Biochemistry; Biology, General
• Keywords: Science & Technology; Life Sciences & Biomedicine; Biochemistry & Molecular Biology; OXYGEN ACTIVATION; PICHIA-PASTORIS; MAO; INHIBITION; EXPRESSION

Abstract

Cardiac senescence is a typical chronic frailty condition in the elderly population, and cellular aging is often associated with oxidative stress. The mitochondrial-membrane flavoenzyme monoamine oxidase A (MAO A) catalyzes the oxidative deamination of neurotransmitters, and its expression increases in aged hearts. We produced recombinant human MAO A variants at Lys305 that play a key role in O2 reactivity leading to H2O2 production. The K305Q variant is as active as the wild-type enzyme, whereas K305M and K305S have 200-fold and 100-fold lower kcat values and similar Km. Under anaerobic conditions, K305M MAO A was normally reduced by substrate, whereas reoxidation by O2 was much slower but could be accomplished by quinone electron acceptors. When overexpressed in cardiomyoblasts by adenoviral vectors, the K305M variant showed enzymatic turnover similar to that of the wild-type but displayed decreased ROS levels and senescence markers. These results might translate into pharmacological treatments as MAO inhibitors may attenuate cardiomyocytes aging.