Instability in NAD Metabolism Leads to Impaired Cardiac Mitochondrial
RESEARCH ARTICLE Instability in NAD+ metabolism leads to impaired cardiac mitochondrial function and communication Knut H Lauritzen1*, Maria Belland Olsen1, Mohammed Shakil Ahmed2, Kuan Yang1, Johanne Egge Rinholm3, Linda H Bergersen4,5, Qin Ying Esbensen6, Lars Jansen Sverkeli7, Mathias Ziegler7, Ha˚ vard Attramadal2, Bente Halvorsen1,8, Pa˚ l Aukrust1,8,9, Arne Yndestad1,8 1Research Institute of Internal Medicine, Oslo University Hospital, Rikshospitalet and University of Oslo, Oslo, Norway; 2Institute for Surgical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; 3Department of Microbiology, Oslo University Hospital, Oslo, Norway; 4Department of Oral Biology, University of Oslo, Oslo, Norway; 5Department of Neuroscience and Pharmacology, Center for Healthy Aging, University of Copenhagen, Copenhagen, Denmark; 6Department of Clinical Molecular Biology, University of Oslo and Akershus University Hospital, Nordbyhagen, Norway; 7Department of Biomedicine, University of Bergen, Bergen, Norway; 8Institute of Clinical Medicine, University of Oslo, Faculty of Medicine, Oslo, Norway; 9Section of Clinical Immunology and Infectious Diseases, Oslo University Hospital Rikshospitalet, Oslo, Norway Abstract Poly(ADP-ribose) polymerase (PARP) enzymes initiate (mt)DNA repair mechanisms and use nicotinamide adenine dinucleotide (NAD+) as energy source. Prolonged PARP activity can drain cellular NAD+ reserves, leading to de-regulation of important molecular processes. Here, we provide evidence of a pathophysiological mechanism that connects mtDNA damage to cardiac *For correspondence: dysfunction via reduced NAD+ levels and loss of mitochondrial function and communication. Using Knut.Huso.Lauritzen@rr-research. a transgenic model, we demonstrate that high levels of mice cardiomyocyte mtDNA damage cause no a reduction in NAD+ levels due to extreme DNA repair activity, causing impaired activation of Competing interests: The NAD+-dependent SIRT3.
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