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The process of aging and circadian rhythms are intimately intertwined, but how peripheral clocks involved in metabolic homeostasis contribute to aging remains unknown. Importantly, caloric restriction (CR) extends lifespan in several organisms and rewires circadian metabolism. Using young versus old mice, fed ad libitum or under CR, we reveal reprogramming of the circadian transcriptome in the liver. These age-dependent changes occur in a highly tissue-specific manner, as demonstrated by comparing circadian gene expression in the liver versus epidermal and skeletal muscle stem cells. Moreover, de novo oscillating genes under CR show an enrichment in SIRT1 targets in the liver. This is accompanied by distinct circadian hepatic signatures in NAD+-related metabolites and cyclic global protein acetylation. Strikingly, this oscillation in acetylation is absent in old mice while CR robustly rescues global protein acetylation. Our findings indicate that the clock operates at the crossroad between protein acetylation, liver metabolism, and aging.

Impaired autophagy is known to cause mitochondrial dysfunction and heart failure, in part due to altered mitophagy and protein quality control. However, whether additional mechanisms are involved in the development of mitochondrial dysfunction and heart failure in the setting of deficient autophagic flux remains poorly explored. Here, we show that impaired autophagic flux reduces nicotinamide adenine dinucleotide (NAD+) availability in cardiomyocytes. NAD+ deficiency upon autophagic impairment is attributable to the induction of nicotinamide N-methyltransferase (NNMT), which methylates the NAD+ precursor nicotinamide (NAM) to generate N-methyl-nicotinamide (MeNAM). The administration of nicotinamide mononucleotide (NMN) or inhibition of NNMT activity in autophagy-deficient hearts and cardiomyocytes restores NAD+ levels and ameliorates cardiac and mitochondrial dysfunction. Mechanistically, autophagic inhibition causes the accumulation of SQSTM1, which activates NF-κB signaling and promotes NNMT transcription. In summary, we describe a novel mechanism illustrating how autophagic flux maintains mitochondrial and cardiac function by mediating SQSTM1-NF-κB-NNMT signaling and controlling the cellular levels of NAD+. Synopsis: How autophagy safeguards cardiac structure and function to prevent heart failure remains unclear. This genetic work links a novel connection between deficient autophagic flux in cardiomyocytes to reduced availability of the cellular metabolite NAD+, suggesting novel tractable avenues for intervention. Depletion of autophagy-related protein 3 (ATG3) in cardiomyocytes causes cardiac dysfunction and early mortality in mice. ATG3 depletion reduces mitochondrial metabolism and biogenesis, preceding age-dependent cardiac dysfunction. Reduced autophagy leads to accumulation of SQSTM1, activation of NF-κB subunit RELA, and increased transcription of the NAD+ metabolic enzyme NNMT. Increased NNMT catalyzes the competing conversion of NAD+ precursor NAM to MeNAM, leading to NAD+ deficiency. Autophagy induction prevents NNMT induction and NNMT inhibition or NMN supplementation restore cardiac and mitochondrial dysfunction when autophagy is defective. Deficient autophagy reduces NAD+ availability in cardiomyocytes via a SQSTM1-NF-κB-NNMT axis, contributing to mitochondrial dysfunction and heart failure. [ABSTRACT FROM AUTHOR]

BACKGROUND. Fasting and [NAD.sup.+]-boosting compounds, including [NAD.sup.+] precursor nicotinamide riboside (NR), confer antiinflammatory effects. However, the underlying mechanisms and therapeutic potential are incompletely defined. METHODS. We explored the underlying biology in myeloid cells from healthy volunteers following in vivo placebo or NR administration and subsequently tested the findings in vitro in monocytes extracted from patients with systemic lupus erythematosus (SLE). RESULTS. RNA-Seq of unstimulated and LPS-activated monocytes implicated NR in the regulation of autophagy and type I IFN signaling. In primary monocytes, NR blunted LPS-induced IFN-[beta] production, and genetic or pharmacological disruption of autophagy phenocopied this effect. Given that [NAD.sup.+] is a coenzyme in oxidoreductive reactions, metabolomics was performed and identified that NR increased the inosine level. Inosine supplementation similarly blunted autophagy and IFN-[beta] release. Finally, because SLE exhibits type I IFN dysregulation, we assessed the NR effect on monocytes from patients with SLE and found that NR reduced autophagy and IFN-[beta] release. CONCLUSION. We conclude that NR, in an [NAD.sup.+]-dependent manner and in part via inosine signaling, mediated suppression of autophagy and attenuated type I IFN in myeloid cells, and we identified NR as a potential adjunct for SLE management. TRIAL REGISTRATION. ClinicalTrials.gov registration numbers NCT02812238, NCT00001846, and NCT00001372. FUNDING. This work was supported by the NHLBI and NIAMS Intramural Research divisions., Introduction Caloric restriction, intermittent fasting, time-restricted feeding, and fasting mimetic diets confer immunomodulatory effects, including amelioration of inflammatory diseases (1-6) and blunting of the NLRP3 inflammasome, circulating cytokines, and acute-phase [...]

DNA methyltransferase 1 (DNMT1) is the enzyme most responsible for epigenetic modification of human DNA and the intended target of approved cancer drugs such as 5-aza-cytidine and 5-aza-2'-deoxycytidine. 5-aza nucleosides have complex mechanisms of action that require incorporation into DNA, and covalent trapping and proteolysis of DNMT isozymes. Direct DNMT inhibitors are needed to refine understanding of the role of specific DNMT isozymes in cancer etiology and, potentially, to improve cancer prevention and treatment. Here, we developed a high throughput pipeline for identification of direct DNMT1 inhibitors. The components of this screen include an activated form of DNMT1, a restriction enzyme-coupled fluorigenic assay performed in 384 well plates with a z-factor of 0.66, a counter screen against the restriction enzyme, a screen to eliminate DNA intercalators, and a differential scanning fluorimetry assay to validate direct binders. Using the Microsource Spectrum collection of 2320 compounds, this screen identified nine compounds with dose responses ranging from 300 nM to 11 µM, representing at least two different pharmacophores with DNMT1 inhibitory activity. Seven of nine inhibitors identified exhibited two to four-fold selectivity for DNMT1 versus DNMT3A.

Alzheimer's Disease (AD) is an aging-associated neurodegenerative disorder, threatening millions of people worldwide. The onset and progression of AD can be accelerated by environmental risk factors, such as bacterial and viral infections. Human herpesviruses are ubiquitous infectious agents that underpin numerous inflammatory disorders including neurodegenerative diseases. Published studies concerning human herpesviruses in AD imply an active role HSV-1 in the pathogenesis of AD. This review will summarize the current understanding of HSV-1 infection in AD and highlight some barriers to advance this emerging field. [ABSTRACT FROM AUTHOR]

Introduction: Cancer inequity is one of the most critical public health issues faced by ethnic minorities and people of lower socioeconomic status. The disparate burden of cancer is caused by poor access to care and inadequate delivery of cancer treatment, as well as comorbid and co-occurring conditions. Diabetes is a common and serious comorbid condition of cancer. Methods: To better understand diabetes prevalence among diverse cancer patients, this study analyzed and described characteristics of cancer patients with diabetes from local-level Service Planning Area (SPA) data using City of Hope Comprehensive Cancer Center data, and United States national-level data from The National Health Interview Survey. Results: Findings from national level data showed that patients in racial/ethnic minority groups had a higher occurrence of being diagnosed with diabetes, especially for non-Hispanic Blacks (OR=1.76, 95% CI=1.51, 2.03) and Hispanic/ Latino individuals (OR=1.34, 95% CI=1.18, 1.52). Cancer patients who are older, ethnic minority, overweight/obese and with lower educational levels were more likely to have co-occurring diabetes. SPA-level patient data found similar results. Discussion: In response to our findings and other reports, clinicians and health system including health coverage organizations should routinely assess cancer patients for cooccurring chronic illnesses, in particular diabetes. Interventions improving coordinated care that integrates oncology, endocrinology and primary care, targeting cancer patients -especially racial/ethnic minorities, overweight/obese, and older patients who are at increased risk for diabetes - ought to be considered as best practice Whole Person care. With coordinated care management, ethnic disparities in cancer may be better addressed and reduced. Additionally, policymakers can contribute by enacting policies improving access to and coverage of integrated oncology, chronic disease prevention, and associated specialty care i.e., endocrinology to equalize quality care for ethnic minority, lower educated, overweight/obese and older cancer patients who are more likely to suffer greater comorbidity, and inadequate oncology and coordinated care to reduce disparities. [ABSTRACT FROM AUTHOR]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.cell.2007.03.024 Byline: Peter Belenky (1), Frances G. Racette (2), Katrina L. Bogan (1), Julie M. McClure (2), Jeffrey S. Smith (2), Charles Brenner (1) Abstract: Although NAD.sup.+ biosynthesis is required for Sir2 functions and replicative lifespan in yeast, alterations in NAD.sup.+ precursors have been reported to accelerate aging but not to extend lifespan. In eukaryotes, nicotinamide riboside is a newly discovered NAD.sup.+ precursor that is converted to nicotinamide mononucleotide by specific nicotinamide riboside kinases, Nrk1 and Nrk2. In this study, we discovered that exogenous nicotinamide riboside promotes Sir2-dependent repression of recombination, improves gene silencing, and extends lifespan without calorie restriction. The mechanism of action of nicotinamide riboside is totally dependent on increased net NAD.sup.+ synthesis through two pathways, the Nrk1 pathway and the Urh1/Pnp1/Meu1 pathway, which is Nrk1 independent. Additionally, the two nicotinamide riboside salvage pathways contribute to NAD.sup.+ metabolism in the absence of nicotinamide-riboside supplementation. Thus, like calorie restriction in the mouse, nicotinamide riboside elevates NAD.sup.+ and increases Sir2 function. Author Affiliation: (1) Departments of Genetics and Biochemistry and the Norris Cotton Cancer Center, Dartmouth Medical School, Rubin 733-HB7937, Lebanon, NH 03756, USA (2) Department of Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, VA 22908, USA Article History: Received 11 December 2006; Revised 7 February 2007; Accepted 16 March 2007 Article Note: (miscellaneous) Published: May 3, 2007