Adipocyte NMNAT1 expression is essential for nuclear NAD biosynthesis but dispensable for regulating thermogenesis and whole-body energy metabolism.

Nicotinamide adenine dinucleotide (NAD) functions as an essential cofactor regulating a variety of biological processes. The purpose of the present study was to determine the role of nuclear NAD biosynthesis, mediated by nicotinamide mononucleotide adenylyltransferase 1 (NMNAT1), in thermogenesis and whole-body energy metabolism. We first evaluated the relationship between NMNAT1 expression and thermogenic activity in brown adipose tissue (BAT), a key organ for non-shivering thermogenesis.

SIRT1 selectively exerts the metabolic protective effects of hepatocyte nicotinamide phosphoribosyltransferase.

Calorie restriction abates aging and cardiometabolic disease by activating metabolic signaling pathways, including nicotinamide adenine dinucleotide (NAD) biosynthesis and salvage. Nicotinamide phosphoribosyltransferase (NAMPT) is rate-limiting in NAD salvage, yet hepatocyte NAMPT actions during fasting and metabolic duress remain unclear. We demonstrate that hepatocyte NAMPT is upregulated in fasting mice, and in isolated hepatocytes subjected to nutrient withdrawal.

Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women.

In rodents, obesity and aging impair nicotinamide adenine dinucleotide (NAD) biosynthesis, which contributes to metabolic dysfunction. Nicotinamide mononucleotide (NMN) availability is a rate-limiting factor in mammalian NAD biosynthesis. We conducted a 10-week, randomized, placebo-controlled, double-blind trial to evaluate the effect of NMN supplementation on metabolic function in postmenopausal women with prediabetes who were overweight or obese.

Removal of Epididymal Visceral Adipose Tissue Prevents Obesity-Induced Multi-organ Insulin Resistance in Male Mice.

Obesity is associated with insulin resistance, an important risk factor of type 2 diabetes, atherogenic dyslipidemia, and nonalcoholic fatty liver disease. The major purpose of this study was to test hypothesize that prophylactic removal of epididymal visceral adipose tissue (VAT) prevents obesity-induced multi-organ (liver, skeletal muscle, adipose tissue) insulin resistance. Accordingly, we surgically removed epididymal VAT pads from adult C57BL/6J mice and evaluated in vivo and cellular metabolic pathways involved in glucose and lipid metabolism following chronic high-fat diet (HFD) feeding.

Importance of Adipose Tissue NAD+ Biology in Regulating Metabolic Flexibility.

Nicotinamide adenine dinucleotide (NAD+) is an essential coenzyme that regulates cellular energy metabolism in many cell types. The major purpose of the present study was to test the hypothesis that NAD+ in white adipose tissue (WAT) is a regulator of whole-body metabolic flexibility in response to changes in insulin sensitivity and with respect to substrate availability and use during feeding and fasting conditions. To this end, we first evaluated the relationship between WAT NAD+ concentration and metabolic flexibility in mice and humans.

Adipose tissue NAD biosynthesis is required for regulating adaptive thermogenesis and whole-body energy homeostasis in mice.

Nicotinamide adenine dinucleotide (NAD) is a critical coenzyme for cellular energy metabolism. The aim of the present study was to determine the importance of brown and white adipose tissue (BAT and WAT) NAD metabolism in regulating whole-body thermogenesis and energy metabolism. Accordingly, we generated and analyzed adipocyte-specific nicotinamide phosphoribosyltransferase () knockout (ANKO) and brown adipocyte-specific knockout (BANKO) mice because NAMPT is the rate-limiting NAD biosynthetic enzyme.

Metabolic importance of adipose tissue monoacylglycerol acyltransferase 1 in mice and humans.

Adipocyte triglyceride storage provides a reservoir of energy that allows the organism to survive times of nutrient scarcity, but excessive adiposity has emerged as a health problem in many areas of the world. Monoacylglycerol acyltransferase (MGAT) acylates monoacylglycerol to produce diacylglycerol; the penultimate step in triglyceride synthesis. However, little is known about MGAT activity in adipocytes, which are believed to rely primarily on another pathway for triglyceride synthesis.

NAD-dependent deacetylase SIRT3 in adipocytes is dispensable for maintaining normal adipose tissue mitochondrial function and whole body metabolism.

Mitochondrial dysfunction in adipose tissue is involved in the pathophysiology of obesity-induced systemic metabolic complications, such as type 2 diabetes, insulin resistance, and dyslipidemia. However, the mechanisms responsible for obesity-induced adipose tissue mitochondrial dysfunction are not clear. The aim of present study was to test the hypothesis that nicotinamide adenine dinucleotide (NAD)-dependent deacetylase sirtuin-3 (SIRT3) in adipocytes plays a critical role in adipose tissue mitochondrial biology and obesity.

Diurnal Variation in PDK4 Expression Is Associated With Plasma Free Fatty Acid Availability in People.

Context: Many biological pathways involved in regulating substrate metabolism display rhythmic oscillation patterns. In rodents, clock genes regulate circadian rhythms of metabolic genes and substrate metabolism. However, the interrelationships among substrate metabolism, metabolic genes, and clock genes have not been fully explored in people.

NAMPT-Mediated NAD(+) Biosynthesis in Adipocytes Regulates Adipose Tissue Function and Multi-organ Insulin Sensitivity in Mice.

Obesity is associated with adipose tissue dysfunction and multi-organ insulin resistance. However, the mechanisms of such obesity-associated systemic metabolic complications are not clear. Here, we characterized mice with adipocyte-specific deletion of nicotinamide phosphoribosyltransferase (NAMPT), a rate-limiting NAD(+) biosynthetic enzyme known to decrease in adipose tissue of obese and aged rodents and people.