NAD+ biosynthesis, aging, and disease

<ns4:p>Nicotinamide adenine dinucleotide (NAD<ns4:sup>+</ns4:sup>) biosynthesis and its regulation have recently been attracting markedly increasing interest. Aging is marked by a systemic decrease in NAD<ns4:sup>+</ns4:sup> across multiple tissues. The dysfunction of NAD<ns4:sup>+</ns4:sup> biosynthesis plays a critical role in the pathophysiologies of multiple diseases, including age-associated metabolic disorders, neurodegenerative diseases, and mental disorders. As downstream effectors, NAD<ns4:sup>+</ns4:sup>-dependent enzymes, such as sirtuins, are involved in the progression of such disorders. These recent studies implicate NAD<ns4:sup>+</ns4:sup> biosynthesis as a potential target for preventing and treating age-associated diseases. Indeed, new studies have demonstrated the therapeutic potential of supplementing NAD<ns4:sup>+</ns4:sup> intermediates, such as nicotinamide mononucleotide and nicotinamide riboside, providing a proof of concept for the development of an effective anti-aging intervention.</ns4:p>