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The correlation between liver disease and the progression of ulcerative colitis (UC) has remained elusive. In this study, it demonstrates that liver injury is intricately linked to the heightened severity of UC in patients, and causes more profound intestinal damage during DSS‐induced colitis in mice. Metabolomics analysis of plasma from liver cirrhosis patients shows liver injury compromising nicotinamide supply for NAD+ biosynthesis in the intestine. Subsequent investigation identifies intestinal group 2 innate lymphoid cells (ILC2s) are responsible for liver injury‐exacerbated colitis. Reconstitution of ILC2s or the restoration of NAD+ metabolism proves effective in relieving liver injury‐aggravated experimental colitis. Mechanistically, the NAD+ salvage pathway regulates gut ILC2s in a cell‐intrinsic manner by supporting the generation of succinate, which fuels the electron transport chain to sustaining ILC2s function. This research deepens the understanding of cellular and molecular mechanisms in liver disease‐UC interplay, identifying a metabolic target for innovative treatments in liver injury‐complicated colitis. [ABSTRACT FROM AUTHOR]

Objective To investigate the correlation of the serum levels of adiponectin, omentin, and visfatin with the severity of acute pancreatitis (AP) . Methods Blood samples were collected from 35 healthy individuals in the control group and 70 patients with AP who were admitted to Chenggong Hospital Affiliated to Xiamen University from March 2022 to October 2023, and enzymelinked immunosorbent assay was used to measure the serum levels of adiponectin, omentin, and visfatin in each group within 24 hours after admission. The analysis of variance was used for comparison of continuous between groups, and the LSD-t test was used for further comparison between two groups; the chi-square test was used for comparison of categorical data between groups. The Pearson correlation analysis was used to investigate the correlation between indicators, and the receiver operating characteristic (ROC) curve was used to investigate the value of the three indicators in predicting severe acute pancreatitis (SAP) . Results Compared with the control group, the AP group had significantly higher serum levels of omentin and visfatin (t=5.51 and 9.41, both P<0.01), and the level of visfatin gradually increased with the aggravation of the disease (F=43.32, P<0.01), while there was no significant change in omentin with the aggravation of the disease (F=0.47, P>0.05) . The AP group had a significantly lower level of adiponectin than the control group (t= − 14.47, P <0.01), and the level of adiponectin gradually decreased with the aggravation of the disease (F=35.61, P<0.01) . The serum level of visfatin was positively correlated with Acute Physiology and Chronic Health Evaluation II (APACHE-II) score (r=0.547, P<0.01), and the level of adiponectin was negatively correlated with APACHE-II score (r=−0.520, P<0.01), while there was no significant correlation between omentin APACHE-II score (r=0.007, P >0.05) . The three indicators had an area under the ROC curve (AUC) of 0.893, 0.570, and 0.829, respectively, in predicting SAP, and combined measurement of adiponectin and visfatin with an AUC of >0.7 showed an AUC of 0.953 in predicting SAP, with a sensitivity of 0.900 and a specificity of 0.933. Conclusion The serum levels of adiponectin and visfatin are correlated with the severity of AP and have an important clinical significance in predicting SAP, and combined measurement of the two indicators has a higher value, while further studies are needed to investigate the correlation of omentin level with the severity of AP [ABSTRACT FROM AUTHOR]

Abstract The correlation between liver disease and the progression of ulcerative colitis (UC) has remained elusive. In this study, it demonstrates that liver injury is intricately linked to the heightened severity of UC in patients, and causes more profound intestinal damage during DSS‐induced colitis in mice. Metabolomics analysis of plasma from liver cirrhosis patients shows liver injury compromising nicotinamide supply for NAD+ biosynthesis in the intestine. Subsequent investigation identifies intestinal group 2 innate lymphoid cells (ILC2s) are responsible for liver injury‐exacerbated colitis. Reconstitution of ILC2s or the restoration of NAD+ metabolism proves effective in relieving liver injury‐aggravated experimental colitis. Mechanistically, the NAD+ salvage pathway regulates gut ILC2s in a cell‐intrinsic manner by supporting the generation of succinate, which fuels the electron transport chain to sustaining ILC2s function. This research deepens the understanding of cellular and molecular mechanisms in liver disease‐UC interplay, identifying a metabolic target for innovative treatments in liver injury‐complicated colitis.

ABSTRACTNicotinamide Adenine Dinucleotide (NAD) is an endogenous substance in redox reactions and regulates various functions in metabolism. NAD and its precursors are known for their anti-ageing and anti-obesity properties and are mainly active in the liver and muscle. Boosting NAD+ through supplementation with the precursors, such as nicotinamide mononucleotide (NMN) or nicotinamide riboside (NR), enhances insulin sensitivity and circadian rhythm in the liver, and improves mitochondrial function in the muscle. Recent evidence has revealed that the adipose tissue could be another direct target of NAD supplementation by attenuating inflammation and fat accumulation. Moreover, murine studies with genetically modified models demonstrated that nicotinamide phosphoribosyltransferase (NAMPT), a NAD regulatory enzyme that synthesizes NMN, played a critical role in lipogenesis and lipolysis in an adipocyte-specific manner. The tissue-specific effects of NAD+ metabolic pathways indicate a potential of the NAD precursors to control metabolic stress particularly via focusing on adipose tissue. Therefore, this narrative review raises an importance of NAD metabolism in white adipose tissue (WAT) through a variety of studies using different mouse models.

Emerging evidence has implicated nicotinamide adenine dinucleotide (NAD+) metabolism in various inflammatory diseases. In the study, the role of NAD+ metabolism in Complete Freund's Adjuvant (CFA)‐evoked inflammatory pain and the underlying mechanisms are investigated. The study demonstrated that CFA induced upregulation of nicotinamide phosphoribosyltransferase (NAMPT) in dorsal root ganglia (DRG) without significant changes in the spinal cord. Inhibition of NAMPT expression by intrathecal injection of NAMPT siRNA alleviated CFA‐induced pain‐like behavior, decreased NAD+ contents in DRG, and lowered poly‐(ADP‐ribose) polymerase 1 (PARP1) activity levels. These effects are all reversed by the supplement of nicotinamide mononucleotide (NMN). Inhibition of PARP1 expression by intrathecal injection of PARP1 siRNA alleviated CFA‐induced pain‐like behavior, while elevated NAD+ levels of DRG. The analgesic effect of inhibiting NAMPT/NAD+/PARP1 axis can be attributed to the downregulation of the NF‐κB/IL‐1β inflammatory pathway. Double immunofluorescence staining showed that the expression of NAMPT/NAD+/PARP1 axis is restricted to DRG neurons. In conclusion, PARP1 activation in response to CFA stimulation, fueled by NAMPT‐derived NAD+, mediates CFA‐induced inflammatory pain through NF‐κB/IL‐1β inflammatory pathway. [ABSTRACT FROM AUTHOR]

Objective　To investigate the protective effect of salidroside against nonalcoholic fatty liver disease （NAFLD） and its mechanism of action. Methods　A total of 24 male KM mice were randomly divided into normal group， HFD group， HFD+blank control group， and HFD+salidroside group， with 6 mice in each group. The mice in the normal group were given normal diet， and those in the other groups were given high-fat diet. After 14 weeks of modeling， the mice were given salidroside 100 mg/kg/day by gavage， and related samples were collected at the end of week 22. Enzyme-linked immunosorbent assay was used to measure the serum levels of related biochemical parameters including alanine aminotransferase （ALT）， aspartate aminotransferase （AST）， triglyceride （TG）， total cholesterol （TC）， high-density lipoprotein cholesterol （HDL-C）， and low-density lipoprotein cholesterol （LDL-C）； HE staining and NAFLD activity score （NAS） were used to observe the liver histopathology of mice； Western blot was used to measure the changes in the expression of NAMPT， Sirt1， AMPKα， and SREBP1 in liver tissue. A one-way analysis of variance was used for comparison between multiple groups， and the least significant difference t-test was used for further comparison between two groups. Results　Compared with the normal group， the HFD group had obvious steatosis and extensive large lipid droplets in liver tissue， with significant increases in NAS score （P<0.01） and the content of AST， ALT， TG， TC， and LDL-C in peripheral blood （all P<0.05） and a significant reduction in the content of HDL-C （P<0.05）， as well as significant reductions in the expression levels of NAMPT， AMPKα， and Sirt1 in liver tissue （all P<0.05） and a significant increase in the expression level of SERBP1 （P<0.01）. Compared with the HFD group and the HFD+blank control group， the HFD+salidroside group had reductions in the distribution of vacuolar lipid droplets and intralobular inflammation in liver tissue， alleviation of the ballooning degeneration of hepatocytes， significant reductions in NAS score（ P<0.01） and the content of AST， ALT， TG， and LDL-C in peripheral blood（ all P< 0.05）， and a significant increase in the content of HDL-C （P<0.05）， as well as significant increases in the expression levels of NAMPT， AMPKα， and Sirt1 in liver tissue （all P<0.05） and a significant reduction in the expression level of SERBP1 （P<0.01）. Conclusion　Salidroside can significantly improve the pathological state of mice with NAFLD induced by high-fat diet and exert a protective effect against NAFLD by increasing the expression of NAMPT， Sirt1， and AMPKα and reducing the expression of SERBP1. [ABSTRACT FROM AUTHOR]

To reveal the effects of nicotinamide phosphoribosyltransferase (Nampt) and high glucose and high insulin (HG+HI) microenvironment on proliferation and metastasis of human cisplatin-resistant lung cancer cell lines. Human cisplatin resistant cell line A549/DDP was divided into 6 groups (n=6): control group, high glucose and high insulin intervention group (HH, cultured with 30 mmol/L glucose and 500 mU/L insulin for 72 h), sh-NC and sh-Nampt transfected groups (Lipofectamine 2000 was used to transfect sh-NC and sh-Nampt into cells respectively, the transfection time was 48 h), HH intervention sh-NC and sh-Nampt groups (HH+sh-NC and HH+sh-Nampt). Each group had 6 replicates. The transfection efficiency was detected by qRT-PCR. Cell proliferation was detected by MTT method, apoptosis was detected by flow cytometry, cell migration and invasion were detected by Transwell, Nampt mRNA was detected by qRT-PCR, and protein expression of Nampt, Bcl-2, Bax, MMP-2, MMP-9, p-PI3K, PI3K, p-AKT and AKT were detected by Western blot. Compared with control group and sh-NC group, the expression level of Nampt mRNA and protein, relative cell viability, the number of migratory and invasive cells decreased, the rate of apoptosis increased, the expression level of Bcl-2, MMP-2, MMP-9, Nampt, p-PI3K and p-AKT protein decreased, and the expression level of Bax protein increased in sh-Nampt group (P<0.05). Compared with control group and sh-NC group, the expression level of Nampt mRNA and protein, relative cell viability, the number of migratory and invasive cells increased, the expression level of Bcl-2, MMP-2, MMP-9, Nampt, p-PI3K and p-AKT protein increased, and the expression level of Bax protein decreased in HH group and HH+sh-NC group (P<0.05). Compared with HH group and HH+sh-NC group, the expression level of Nampt mRNA and protein, relative cell viability, the number of migratory and invasive cells decreased, the rate of apoptosis increased, the expression level of Bcl-2, MMP-2, MMP-9, Nampt, p-PI3K and p-AKT protein decreased, and the expression level of Bax protein increased in HH+sh-Nampt group(P<0.05). High glucose and high insulin microenvironment may induce proliferation and metastasis of human cisplatin-resistant lung cancer cells by up-regulating Nampt/PI3K/AKT signaling pathway. [ABSTRACT FROM AUTHOR]

Emerging evidence suggests that intratumoral interferon (IFN) signaling can trigger targetable vulnerabilities. A hallmark of pancreatic ductal adenocarcinoma (PDAC) is its extensively reprogrammed metabolic network, in which nicotinamide adenine dinucleotide (NAD) and its reduced form, NADH, are critical cofactors. Here, we show that IFN signaling, present in a subset of PDAC tumors, substantially lowers NAD(H) levels through up-regulating the expression of NAD-consuming enzymes PARP9, PARP10, and PARP14. Their individual contributions to this mechanism in PDAC have not been previously delineated. Nicotinamide phosphoribosyltransferase (NAMPT) is the rate-limiting enzyme in the NAD salvage pathway, a dominant source of NAD in cancer cells. We found that IFN-induced NAD consumption increased dependence upon NAMPT for its role in recycling NAM to salvage NAD pools, thus sensitizing PDAC cells to pharmacologic NAMPT inhibition. Their combination decreased PDAC cell proliferation and invasion in vitro and suppressed orthotopic tumor growth and liver metastases in vivo.

ObjectiveAging is associated with decreased nicotinamide adenine dinucleotide (NAD) levels, which in turn cause dysfunctional mitochondria and indirectly affect a myriad of diseases. Intracellular nicotinamide phosphoribosyltransferase (iNAMPT) serves as a central rate-limiting enzyme in NAD synthesis, making it an indispensable health mediator. This meta-analysis examined the effect of exercise training on the expression of iNAMPT in humans.MethodsWe searched PubMed, Scopus, ClinicalTrials.gov, and the International Clinical Trials Registry Platform for studies published between the inception of the database and July 5, 2023. Using the common-effect model, evidence for the change in iNAMPT following exercise training was synthesized as Cohen’s d.ResultsThe search yielded five eligible studies. The overall effect size is 0.81, with a 95% confidence interval of 0.55 to 1.07. Therefore, a random adult will have a 71.7% probability that iNAMPT will be up-regulated following exercise training. In general, exercise training resulted in a 1.46-fold increase in iNAMPT. Our probability statistics indicate that subgroups of interest may differ practically. Specifically, there is a 79.3% probability of increased iNAMPT in men, compared to a 69.0% probability in the overall population; young adults have a 75.6% probability of having an increased iNAMPT, whereas aged adults have a 68.7% probability; and, iNAMPT has a 75.1% probability increase after aerobic exercise and a 66.4% probability increase after resistance exercise.ConclusionExercise training is effective for increasing iNAMPT levels in skeletal muscles. This essential enzyme regulates not only cellular energetics but also healthspan. Therefore, exercise should be promoted as a natural slow-aging lifestyle.

Purpose: To investigate the role of nicotinamide phosphoribosyltransferase (NAMPT) in lipopolysaccharide (LPS)-induced damage in trophoblastic HTR-8/SVneo cells (HTR8 cells), with the aim of ultimately providing new therapeutic targets of preeclampsia (PE). Methods: Trophoblastic HTR-8/SVneo was cultured and treated with LPS to mimic PE in vitro, while FK866, an antagonist of NAMPT, was used to establish an inflammatory model of HTR8 cells. Western blot, enzyme-linked immunosorbent assay (ELISA) and quantitative real-time-polymerase chain reaction (qRT-PCR) were used to evaluate inflammatory response in HTR8 cells, and cell counting kit-8 (CCK8) and oxidative stress kits were performed to quantify cell activity in HTR cells. Results: Compared with the control group, the administration of LPS significantly increased the expression levels of NAMPT in HTR8 cells. FK866 suppressed the expression levels of pro)inflammatory factors IL-1β, TNF-α and IL-6, and alleviated inflammation by inhibiting NAMPT-mediated NF-κB pathway. The antioxidant effect of FK866 was achieved via activation of antioxidant proteins, catalase (CAT) and glutathione (GSH). Conclusion: FK866 protects HTR8 cells from LPS-induced inflammation and oxidative stress through the inhibition of NAMPT-NF-κB signaling pathway. Thus, NAMPT is a potential therapeutic target for preeclampsia (PE). [ABSTRACT FROM AUTHOR]

Nicotinamide mononucleotide (NMN) is an essential precursor of nicotinamide adenine dinucleotide (NAD+), which is widely applied in the pharmaceutical and biotech industries. The biosynthesis of NMN is currently attracting much attention because it has non-toxic reaction conditions and low amounts of isomers, whereas chemical synthesis has low yields and is not environmentally friendly. This review systematically describes the two biosynthetic pathways of NMN in detail for the first time and introduces the latest studies on NMN production through different pathways using metabolic engineering strategies. NMN accumulation can be improved by optimizing the activity of key enzymes, enhancing the supply of precursors and co-factors, inhibiting the synthesis of byproducts, and promoting product export. Finally, we also discuss the current challenges of producing NMN and possible solutions for the future. [ABSTRACT FROM AUTHOR]

All cells require sustained intracellular energy flux, which is driven by redox chemistry at the subcellular level. NAD+, its phosphorylated variant NAD(P)+, and its reduced forms NAD(P)/NAD(P)H are all redox cofactors with key roles in energy metabolism and are substrates for several NAD-consuming enzymes (e.g. poly(ADP-ribose) polymerases, sirtuins, and others). The nicotinamide salvage pathway, constituted by nicotinamide mononucleotide adenylyltransferase (NMNAT) and nicotinamide phosphoribosyltransferase (NAMPT), mainly replenishes NAD+ in eukaryotes. However, unlike NMNAT1, NAMPT is not known to be a nuclear protein, prompting the question of how the nuclear NAD+ pool is maintained and how it is replenished upon NAD+ consumption. In the present work, using human and murine cells; immunoprecipitation, pulldown, and surface plasmon resonance assays; and immunofluorescence, small-angle X-ray scattering, and MS-based analyses, we report that GAPDH and NAMPT form a stable complex that is essential for nuclear translocation of NAMPT. This translocation furnishes NMN to replenish NAD+ to compensate for the activation of NAD-consuming enzymes by stressful stimuli induced by exposure to H2O2 or S-nitrosoglutathione and DNA damage inducers. These results indicate that by forming a complex with GAPDH, NAMPT can translocate to the nucleus and thereby sustain the stress-induced NMN/NAD+ salvage pathway.

Abstract Objective The aim of this study was to investigate the potential role of serum nicotinamide phosphoribosyltransferase (NAMPT) in non-traumatic osteonecrosis of femoral head (NONFH). Methods A total of 113 NONFH patients and 81 healthy individuals were included in this study. The NAMPT levels in serum were measured by a commercial enzyme-linked immunosorbent assay kit. Radiographic progression was determined using Association Research Circulation Osseous (ARCO) classification system. Clinical severity was assessed by Harris hip score (HHS) and visual analogue scale (VAS). Correlations between serum NAMPT and radiographic progression as well as clinical severity were evaluated statistically. Receiver operating characteristic (ROC) curves were performed to evaluate the diagnostic values of NAMPT in NONFH potential and disease severity. Results The serum NAMPT levels in NONFH patients were significantly lower than that in healthy controls. There were no significant differences among alcohol-induced group, steroids-induced group, and idiopathic group. NONFH patients with ARCO stage 4 had significant lower serum NAMPT levels in comparisons with ARCO stage 3 and 2, respectively. Lower serum NAMPT levels were also observed in bilateral NONFH cases compared with cases with unilateral NONFH. In addition, serum NAMPT was negatively correlated with ARCO stages and VAS scores, and positively correlated with HHS. ROC curve analysis indicated that serum NAMPT may serve as a novel biomarker for diagnosing early NONFH and for monitoring disease severity. Conclusions Our results suggest that serum NAMPT may serve as a novel biomarker for NONFH potential and disease severity.

The intestine has garnered attention as a target organ for developing new therapies for impaired glucose tolerance. The intestine, which produces incretin hormones, is the central regulator of glucose metabolism. Glucagon-like peptide-1 (GLP-1) production, which determines postprandial glucose levels, is regulated by intestinal homeostasis. Nicotinamide phosphoribosyltransferase (NAMPT)-mediated nicotinamide adenine dinucleotide (NAD+) biosynthesis in major metabolic organs such as the liver, adipose tissue, and skeletal muscle plays a crucial role in obesity- and aging-associated organ derangements. Furthermore, NAMPT-mediated NAD+ biosynthesis in the intestines and its upstream and downstream mediators, adenosine monophosphate-activated protein kinase (AMPK) and NAD+-dependent deacetylase sirtuins (SIRTs), respectively, are critical for intestinal homeostasis, including gut microbiota composition and bile acid metabolism, and GLP-1 production. Thus, boosting the intestinal AMPK–NAMPT–NAD+–SIRT pathway to improve intestinal homeostasis, GLP-1 production, and postprandial glucose metabolism has gained significant attention as a novel strategy to improve impaired glucose tolerance. Herein, we aimed to review in detail the regulatory mechanisms and importance of intestinal NAMPT-mediated NAD+ biosynthesis in regulating intestinal homeostasis and GLP-1 secretion in obesity and aging. Furthermore, dietary and molecular factors regulating intestinal NAMPT-mediated NAD+ biosynthesis were critically explored to facilitate the development of new therapeutic strategies for postprandial glucose dysregulation. [ABSTRACT FROM AUTHOR]

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 (Nampt) knockout (ANKO) and brown adipocyte-specific Nampt knockout (BANKO) mice because NAMPT is the rate-limiting NAD+ biosynthetic enzyme. We found ANKO mice, which lack NAMPT in both BAT and WAT, had impaired gene programs involved in thermogenesis and mitochondrial function in BAT and a blunted thermogenic (rectal temperature, BAT temperature, and whole-body oxygen consumption) response to acute cold exposure, prolonged fasting, and administration of β-adrenergic agonists (norepinephrine and CL-316243). In addition, the absence of NAMPT in WAT markedly reduced adrenergic-mediated lipolytic activity, likely through inactivation of the NAD+-SIRT1-caveolin-1 axis, which limits an important fuel source fatty acid for BAT thermogenesis. These metabolic abnormalities were rescued by treatment with nicotinamide mononucleotide (NMN), which bypasses the block in NAD+ synthesis induced by NAMPT deficiency. Although BANKO mice, which lack NAMPT in BAT only, had BAT cellular alterations similar to the ANKO mice, BANKO mice had normal thermogenic and lipolytic responses. We also found NAMPT expression in supraclavicular adipose tissue (where human BAT is localized) obtained from human subjects increased during cold exposure, suggesting our finding in rodents could apply to people. These results demonstrate that adipose NAMPT-mediated NAD+ biosynthesis is essential for regulating adaptive thermogenesis, lipolysis, and whole-body energy metabolism.

Precision oncology hinges on linking tumour genotype with molecularly targeted drugs1; however, targeting the frequently dysregulated metabolic landscape of cancer has proven to be a major challenge2. Here we show that tissue context is the major determinant of dependence on the nicotinamide adenine dinucleotide (NAD) metabolic pathway in cancer. By analysing more than 7,000 tumours and 2,600 matched normal samples of 19 tissue types, coupled with mathematical modelling and extensive in vitro and in vivo analyses, we identify a simple and actionable set of rules. If the rate-limiting enzyme of de novo NAD synthesis, NAPRT, is highly expressed in a normal tissue type, cancers that arise from that tissue will have a high frequency of NAPRT amplification and be completely and irreversibly dependent on NAPRT for survival. By contrast, tumours that arise from normal tissues that do not express NAPRT highly are entirely dependent on the NAD salvage pathway for survival. We identify the previously unknown enhancer that underlies this dependence. Amplification of NAPRT is shown to generate a pharmacologically actionable tumour cell dependence for survival. Dependence on another rate-limiting enzyme of the NAD synthesis pathway, NAMPT, as a result of enhancer remodelling is subject to resistance by NMRK1-dependent synthesis of NAD. These results identify a central role for tissue context in determining the choice of NAD biosynthetic pathway, explain the failure of NAMPT inhibitors, and pave the way for more effective treatments.

Objective: The aim of this study was to investigate the potential role of serum nicotinamide phosphoribosyltransferase (NAMPT) in non-traumatic osteonecrosis of femoral head (NONFH). Methods: A total of 113 NONFH patients and 81 healthy individuals were included in this study. The NAMPT levels in serum were measured by a commercial enzyme-linked immunosorbent assay kit. Radiographic progression was determined using Association Research Circulation Osseous (ARCO) classification system. Clinical severity was assessed by Harris hip score (HHS) and visual analogue scale (VAS). Correlations between serum NAMPT and radiographic progression as well as clinical severity were evaluated statistically. Receiver operating characteristic (ROC) curves were performed to evaluate the diagnostic values of NAMPT in NONFH potential and disease severity. Results: The serum NAMPT levels in NONFH patients were significantly lower than that in healthy controls. There were no significant differences among alcohol-induced group, steroids-induced group, and idiopathic group. NONFH patients with ARCO stage 4 had significant lower serum NAMPT levels in comparisons with ARCO stage 3 and 2, respectively. Lower serum NAMPT levels were also observed in bilateral NONFH cases compared with cases with unilateral NONFH. In addition, serum NAMPT was negatively correlated with ARCO stages and VAS scores, and positively correlated with HHS. ROC curve analysis indicated that serum NAMPT may serve as a novel biomarker for diagnosing early NONFH and for monitoring disease severity. Conclusions: Our results suggest that serum NAMPT may serve as a novel biomarker for NONFH potential and disease severity. [ABSTRACT FROM AUTHOR]

Adrenocortical carcinomas (ACC) are rare endocrine malignancies, often with a poor prognosis. Visfatin/NAMPT regulates a variety of signaling pathway components, and its overexpression has been found in carcinogenesis. Our study aimed to assess the clinical usefulness of visfatin/NAMPT serum level in discriminating between ACC and benign adrenocortical tumors. Twenty-two patients with ACC and twenty-six patients with benign adrenocortical tumors were recruited. Fasting blood samples were collected from each patient, and visfatin serum levels were measured with the ELISA Kit. Clinical stage, tumor size, Ki67 proliferation index, hormonal secretion pattern, and follow-up were determined in ACC patients. Patients with ACC had significantly higher visfatin serum concentrations (7.81 ± 2.25 vs. 6.08 ± 1.32 ng/mL, p-value = 0.003). The most advanced clinical stage with metastases was associated with significantly elevated visfatin levels (p-value = 0.022). Based on ROC analysis, visfatin serum concentrations higher than 8.05 ng/mL could discriminate ACC with a sensitivity of 50.0% and specificity of 92.3%. Univariate Cox regression indicated that tumor size was significantly related to shorter survival, and the visfatin level was borderline significant in all patients (HR = 1.013, p-value = 0.002, HR = 1.321, p-value = 0.058). In the Kaplan-Meier method, patients with visfatin serum concentrations higher than 6.3 ng/mL presented significantly lower survival probability (p-value = 0.006). Serum visfatin/NAMPT could be a potential risk predictor for the malignancy of adrenal tumors. However, further studies are needed on this subject. [ABSTRACT FROM AUTHOR]

Nicotinamide phosphoribosyltransferase (NAMPT) is a rate-limiting enzyme in the NAD salvage pathway of mammalian cells and is overexpressed in numerous types of cancers. These include breast cancer, ovarian cancer, prostate cancer, gastric cancer, colorectal cancer, glioma, and b-cell lymphoma. NAMPT is also known to impact the NAD and NADPH pool. Research has demonstrated that NAMPT can be inhibited. NAMPT inhibitors are diverse anticancer medicines with significant anti-tumor efficacy in ex vivo tumor models. A few notable NAMPT specific inhibitors which have been produced include FK866, CHS828, and OT-82. Despite encouraging preclinical evidence of the potential utility of NAMPT inhibitors in cancer models, early clinical trials have yielded only modest results, necessitating the adaptation of additional tactics to boost efficacy. This paper examines a number of cancer treatment methods which target NAMPT, including the usage of individual inhibitors, pharmacological combinations, dual inhibitors, and ADCs, all of which have demonstrated promising experimental or clinical results. We intend to contribute further ideas regarding the usage and development of NAMPT inhibitors in clinical therapy to advance the field of research on this intriguing target. [ABSTRACT FROM AUTHOR]

Objective To investigate the relationships between the levels of plasma soluble receptor for advanced glycation end products (sRAGE) and nicotinamide phosphoribosyltransferase (Nampt) and the severity and prognosis of patients with ventilator-associated pneumonia (VAP) . Methods Totally 143 VAP patients (observation group) were selected. According to the degree of disease, they were divided into 38 severe cases, 49 moderate cases, and 56 mild cases. During the follow-up period of 28 days, 41 cases died and 102 cases survived. During the same period, 50 healthy volunteers (control group) were selected. The elbow vein blood was collected, and the plasma was centrifuged to determine the plasma sRAGE and Nampt. The plasma sRAGE and Nampt levels in the observation group, the control group and VAP patients with different conditions were compared, and the relationships between the plasma sRAGE and Nampt levels in the VAP patients and the acute physiology and chronic health assessment Ⅱ (APACHE Ⅱ) score were analyzed. The clinical data of VAP patients were collected, and the influencing factors of poor prognosis were analyzed. Plasma sRAGE and Nampt levels in all subjects were determined by ELISA. Receiver operating characteristic (ROC) curve was used to evaluate the predictive value of plasma sRAGE and Nampt levels for poor prognosis in VAP patients. Results The plasma levels of sRAGE and Nampt in the observation group were significantly higher than those in the control group (both P<0. 01) . With the aggravation of VAP, the levels of plasma sRAGE and Nampt gradually increased (both P<0. 01) . Plasma sRAGE and Nampt levels in VAP patients were positively correlated with APACHE Ⅱ score (both P<0. 01) . Multivariate Logistic regression analysis showed that age ≥60 years, mechanical ventilation time ≥72 h, history of diabetes, tracheotomy, ≥2 lesions involving lobes, APACHE Ⅱ score, sRAGE, and Nampt were independent risk factors for poor prognosis in VAP patients, while mean arterial pressure ≥65 mmHg was an independent protective factor (all P<0. 05) . The area under the ROC curve of plasma sRAGE combined with Nampt levels in predicting poor prognosis of VAP patients was significantly higher than that of plasma sRAGE and Nampt levels alone (both P<0. 05). Conclusions Plasma sRAGE and Nampt levels significantly increase in VAP patients, and their elevated levels are closely related to disease severity and prognosis. Plasma sRAGE and Nampt levels are independent risk factors for poor prognosis in VAP patients, and can be used as biomarkers to predict poor prognosis in VAP patients. [ABSTRACT FROM AUTHOR]

Epidermal hyperplasia and the involvement of immune cells characterize the clinical picture of psoriasis. Among the several factors involved, attention has been focused on sirtuin 1 (SIRT1) - a deacetylase endowed with a variety of functions including the control of metabolic and inflammatory processes-, and on nicotinamide phosphoribosyltransferase (NAMPT), important for SIRT1 activation and involved in inflammatory events. The aim of the study was to analyze changes of SIRT1 and NAMPT expression in psoriatic skin. Samples from healthy controls and psoriatic patients were subjected to immunohistochemical analysis. A strong downregulation of SIRT1 expression was observed in skin samples from psoriatic patients compared to healthy controls. This was accompanied by a parallel reduction of adenosine monophosphate-activated kinase (AMPK) expression and, more strikingly, by the disappearance of cells immunolabeled for its active, phosphorylated form (pAMPK). In both cases, analysis of the distribution of immunopositive cells revealed a shift towards reduced intensity of staining. In contrast, NAMPT expression was upregulated in psoriatic samples in line with its pro-inflammatory role. This was again more visible with an intensity-based distribution analysis that evidenced a shift towards more intensely immunostained cell populations. The present data correlate in the same samples the expression of SIRT1, pAMPK/AMPK and NAMPT in psoriasis and open the way for novel pharmacological targets in the treatment of the disease. [ABSTRACT FROM AUTHOR]

Abstract Background: Migraines are headaches caused by changes in the trigeminovascular metabolic pathway. Migraine headache attacks are associated with neurovascular inflammation, but their pathophysiological mechanisms have not been fully explained. Objective: To investigate the relationship between serum vaspin, visfatin, chemerin and interleukin-18 (IL-18) levels and the frequency of attacks in migraine headache. Methods: Three groups were established: migraine with aura (n = 50), migraine without aura (n = 50) and control group (n = 50). The migraine diagnosis was made in accordance with the International Classification of Headache Disorders-III beta diagnostic criteria. The analyses on serum vaspin, visfatin, chemerin and IL-18 levels were performed using the enzyme-linked immunosorbent assay method. Results: The serum vaspin, visfatin, chemerin and IL-18 levels were found to be significantly higher in the migraine patients than in the control group (p < 0.01). No statistically significant differences in serum vaspin, visfatin, chemerin and IL-18 levels were found among the migraine patients during attacks or in the interictal period (p>0.05). The serum visfatin and chemerin levels of the migraine patients were positively correlated with their serum IL-18 levels (p < 0.01), while their serum chemerin and visfatin levels were positively correlated with their serum vaspin levels (p < 0.05). Conclusions: This study showed that these biomarkers may be related to migraine pathogenesis. Nonetheless, we believe that more comprehensive studies are needed in order to further understand the role of vaspin, visfatin, chemerin and IL-18 levels in the pathophysiology of migraine headaches.

Nicotinamide mononucleotide (NMN) is an essential precursor of nicotinamide adenine dinucleotide (NAD+), which is widely applied in the pharmaceutical and biotech industries. The biosynthesis of NMN is currently attracting much attention because it has non-toxic reaction conditions and low amounts of isomers, whereas chemical synthesis has low yields and is not environmentally friendly. This review systematically describes the two biosynthetic pathways of NMN in detail for the first time and introduces the latest studies on NMN production through different pathways using metabolic engineering strategies. NMN accumulation can be improved by optimizing the activity of key enzymes, enhancing the supply of precursors and co-factors, inhibiting the synthesis of byproducts, and promoting product export. Finally, we also discuss the current challenges of producing NMN and possible solutions for the future.

Breast cancer (BC) is one of the most common causes of cancer in women worldwide and it is found to be associated with an increased level of Nicotinamide phosphoribosyltransferase (NAMPT), which plays an important role in nicotinamide adenine dinucleotide (NAD) pathway, both in blood and tumor tissues. This enzyme is also essential for the growth and survival of cancer cells. The short noncoding RNA microRNAs miR-26b is an important gene regulator and a tumor suppressor in different human cancers, including BC. In this study, bioinformatics analysis was evaluated to find the miRNAs targeting NAMPT 3′ untranslated regions (3′ UTRs), which was confirmed by luciferase assay. Next, we evaluate NAMPT and microRNA-26b (miR-26b) expression by using polymerase chain reaction (PCR) in BC. miR-26b effect on cell viability was also evaluated by Cell Counting Kit-8 (CCK-8). Following transfection with miR-613 mimic, the expression of miR-613 was elevated in the BC cells leading to inhibition of NAMPT expression at both mRNA and protein level as measured by real-time PCR and western blotting. Our result identified a significant tumor suppressor role of miR-26b on NAMPT, NAD concentration, and cell viability in BC. Overall, based on our finding, miR-26b mimic transfection could elevate miR-26b levels in BC cells via downregulating the NAMPT expression, NAD expression levels, and cell growth, whereas miR-26b inhibitor had the opposite function. In conclusion, miR-26b can become a promising target for BC treatment through targeting NAMPT and inhibiting the NAD production. [ABSTRACT FROM AUTHOR]

Nicotinamide phosphoribosyltransferase (NAMPT) is the rate-limiting enzyme in the nicotinamide adenine dinucleotide (NAD) salvage pathway in mammals. It is of great significance in the metabolic homeostasis and cell survival via synthesizing nicotinamide mononucleotide (NMN) through enzymatic activities, serving as a key protein involved in the host's defense mechanism. The NAMPT metabolic pathway connects NADdependent sirtuin (SIRT) signaling, constituting the NAMPT-NAD-SIRT cascade, which is validated as a strong intrinsic defense system. Neurodegenerative diseases belong to the central nervous system (CNS) disease that seriously endangers human health. The World Health Organization (WHO) proposed that neurodegenerative diseases will become the second leading cause of human death in the next two decades. However, effective drugs for neurodegenerative diseases are scant. NAMPT is specifically highly expressed in the hippocampus, which mediates cell self-renewal and proliferation and oligodendrocyte synthesis by inducing the biosynthesis of NAD in neural stem cells/progenitor cells. Owing to the active biological function of NAMPT in neurogenesis, targeting NAMPT may be a powerful therapeutic strategy for neurodegenerative diseases. This study aims to review the structure and biological functions, the correlation with neurodegenerative diseases, and treatment advance of NAMPT, aiming to provide a novel idea for targeted therapy of neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Wencui Wan,1,&ast; Wei Zhu,2,&ast; Yan Wu,3,4,&ast; Yang Long,1 Hongzhuo Liu,1 Weiwei Wan,1 Guangming Wan,1 Jing Yu3 1Department of Ophthalmology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, People’s Republic of China; 2Department of Ophthalmology, Changshu No. 2 People’s Hospital, Changshu, People’s Republic of China; 3Department of Ophthalmology, Shanghai Tenth People’s Hospital, Tongji University, Shanghai, People’s Republic of China; 4Mois Biotech Company, Shanghai, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Guangming WanDepartment of Ophthalmology, First Affiliated Hospital of Zhengzhou University, 1 East Jianshe Road, Zhengzhou, Henan, 450052, People’s Republic of ChinaEmail wgm6608@163.comJing Yu No. 301, Yanchang Road, Shanghai, 200072, People’s Republic of ChinaEmail dryujing@aliyun.comBackground: Retinal pigment epithelium (RPE) cellular senescence is an important process in degenerative retinal disorders. Grape seed proanthocyanidin extract (GSPE) alleviates senescence-related degenerative disorders; however, the potential effects of GSPE intake on RPE cellular senescence through regulating NAMPT/SIRT1/NLRP3 pathway remain unclear.Methods: The effects of GSPE on NAMPT expression and NAD+ contents were detected with Western blot and assay kit in both in-vivo and in-vitro AMD models. Senescence-related biomarkers, including p16, p21 expressions and β-gal staining, were conducted in different groups. The protective effects of GSPE treatment on the mitochondrial homeostasis and barrier function of RPE cells were detected using mtDNA lesions analyses, JC-1 staining, ZO1 staining and trans-epithelial cell resistance (TEER) detection. The expression of senescence-associated secretory phenotype (SASP) in different groups would be conducted with qPCR. To demonstrate the potential effects of NAMPT/SIRT1/NLRP3 pathway after GSPE treatment, the protein levels of relevant key regulators after applications of NAMPT inhibitor, Fk866, and SIRT1 inhibitor, EX-527.Results: GSPE significantly improves the NAMPT expression and NAD+ content in aging mice, and thus alleviates the RPE cellular senescence. In advanced in-vitro studies, GSPE significantly up-regulated NAMPT content and thus relieved H2O2 induced NAD+ depression through analyzing the NAD+ contents in different groups. In advanced analyses, it was reported that GSPE could alleviate mitochondrial permeability, mtDNA damage, ZO1 expression and SASP levels in aging RPE cells. Thus, GSPE treatment significantly decreased senescence-related protein p16 and p21, as well as SASP levels in in-vitro aging model, and it was demonstrated that GSPE could illustrate a significant anti-aging effect. The Western blot data in GSPE treatment of aging RPE cells demonstrated that GSPE could significantly improve NAMPT and SIRT1 levels, and thus depressed NLRP3 expression.Conclusion: This study indicated that GSPE alleviated RPE cellular senescence through NAMPT/SIRT1/NLRP3 pathway. This study highlighted the potential effects of GSPE on degenerative retinopathy through the crosstalk of NAD+ metabolism, SIRT1 function and NLRP3 activation.Keywords: cellular senescence, retinal pigment epithelium, nicotinamide phosphoribosyltransferase, sirtuin 1, inflammasome, NLRP3

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a common hereditary renal disease with no currently available targeted therapies. Based on the established connection between β-catenin signaling and renal ciliopathies, and on data from our and other laboratories showing striking similarities of this disease and cancer, we evaluated the use of an orally bioavailable small molecule, KPT-9274 (a dual inhibitor of the protein kinase PAK4 and nicotinamide phosphoribosyl transferase), for treatment of ADPKD. Treatment of PKD-derived cells with this compound not only reduces PAK4 steady-state protein levels and regulates β-catenin signaling, but also inhibits nicotinamide phosphoribosyl transferase, the rate-limiting enzyme in a key NAD salvage pathway. KPT-9274 can attenuate cellular proliferation and induce apoptosis associated with a decrease in active (phosphorylated) PAK4 and β-catenin in several Pkd1-null murine cell lines, with a less pronounced effect on the corresponding phenotypically normal cells. Additionally, KPT-9274 shows inhibition of cystogenesis in an ex vivo model of cyclic AMP-induced cystogenesis as well as in the early stage Pkd1flox/flox:Pkhd1-Cre mouse model, the latter showing confirmation of specific anti-proliferative, apoptotic, and on-target effects. NAD biosynthetic attenuation by KPT-9274, while critical for highly proliferative cancer cells, does not appear to be important in the slower growing cystic epithelial cells during cystogenesis. KPT-9274 was not toxic in our ADPKD animal model or in other cancer models. Thus, this small molecule inhibitor could be evaluated in a clinical trial as a viable therapy of ADPKD.

Dysregulation of thyroid function has known impact on body metabolism, however, data regarding metabolic outcome after restoration of thyroid function is limited. Therefore, the aim of the study was to investigate the effect of restoratio n of euthyroidism on serum visfatin, and its associations with insulin resistance and body composition. This is an observational study with consecutive enrollment. Forty-nine hyperthyroid (median age of 34 years) and 44 hypothyroid women (median age of 46 years) completed the study. Laboratory parameters and body composition analysis were assessed before and after the therapy. In the hyperthyroid group, visfatin concentrations increased (P < 0.0001), while glucose concentrations decreased (P < 0.0001). Total body mass and fat mass in the trunk and limbs significantly increased during the treatment. In the hypothyroid group, significant weight loss resulted from decrease of fat and muscle masses in trunk and limbs. Visfatin serum concentrations positively correlated with total fat mass (r = 0.19, P = 0.01) and insulin concentrations (r = 0.17, P = 0.018). In conclusion, restoration of thyroid function is not associated with beneficial changes in body compo sition, especially among hyperthyroid females.

An increasing number of studies have shown that nicotinamide mononucleotide (NMN) can inhibit not only ageing but also oxidative stress and inflammatory reactions by improving energy metabolism. However, the role of NMN in regulating the anti‐apoptotic, antioxidative stress and inflammatory responses of brain microvascular endothelial cells is still unknown. Therefore, here we studied the effects of NMN on H2O2‐induced oxidative damage of bEnd.3 cells. In this study, we found that NMN could inhibit the NF‐κBp65 inflammatory signalling pathway and increase the expression of the enzymes NAMPT, VEGF and eNOS, alleviating H2O2‐induced apoptosis in bEnd.3 cells. Taken together, these results suggest that NMN reduces H2O2‐induced oxidative stress and apoptosis and improves cell functions by inhibiting the NF‐κBp65 inflammatory pathway and increasing NAMPT expression.

The intestine has garnered attention as a target organ for developing new therapies for impaired glucose tolerance. The intestine, which produces incretin hormones, is the central regulator of glucose metabolism. Glucagon-like peptide-1 (GLP-1) production, which determines postprandial glucose levels, is regulated by intestinal homeostasis. Nicotinamide phosphoribosyltransferase (NAMPT)-mediated nicotinamide adenine dinucleotide (NAD+) biosynthesis in major metabolic organs such as the liver, adipose tissue, and skeletal muscle plays a crucial role in obesity- and aging-associated organ derangements. Furthermore, NAMPT-mediated NAD+ biosynthesis in the intestines and its upstream and downstream mediators, adenosine monophosphate-activated protein kinase (AMPK) and NAD+-dependent deacetylase sirtuins (SIRTs), respectively, are critical for intestinal homeostasis, including gut microbiota composition and bile acid metabolism, and GLP-1 production. Thus, boosting the intestinal AMPK–NAMPT–NAD+–SIRT pathway to improve intestinal homeostasis, GLP-1 production, and postprandial glucose metabolism has gained significant attention as a novel strategy to improve impaired glucose tolerance. Herein, we aimed to review in detail the regulatory mechanisms and importance of intestinal NAMPT-mediated NAD+ biosynthesis in regulating intestinal homeostasis and GLP-1 secretion in obesity and aging. Furthermore, dietary and molecular factors regulating intestinal NAMPT-mediated NAD+ biosynthesis were critically explored to facilitate the development of new therapeutic strategies for postprandial glucose dysregulation.

The IDH1R132H mutation in glioma results in the neoenzymatic function of IDH1, leading to the production of the oncometabolite 2-hydroxyglutarate (2-HG), alterations in energy metabolism and changes in the cellular redox household. Although shifts in the redox ratio NADPH/NADP+ were described, the consequences for the NAD+ synthesis pathways and potential therapeutic interventions were largely unexplored. Here, we describe the effects of heterozygous IDH1R132H on the redox system in a CRISPR/Cas edited glioblastoma model and compare them with IDH1 wild-type (IDH1wt) cells. Besides an increase in 2-HG and decrease in NADPH, we observed an increase in NAD+ in IDH1R132H glioblastoma cells. RT-qPCR analysis revealed the upregulation of the expression of the NAD+ synthesis enzyme nicotinamide phosphoribosyltransferase (NAMPT). Knockdown of NAMPT resulted in significantly reduced viability in IDH1R132H glioblastoma cells. Given this dependence of IDH1R132H cells on NAMPT expression, we explored the effects of the NAMPT inhibitors FK866, GMX1778 and GNE-617. Surprisingly, these agents were equally cytotoxic to IDH1R132H and IDH1wt cells. Altogether, our results indicate that targeting the NAD+ synthesis pathway is a promising therapeutic strategy in IDH mutant gliomas; however, the agent should be carefully considered since three small-molecule inhibitors of NAMPT tested in this study were not suitable for this purpose. [ABSTRACT FROM AUTHOR]

The paucity of therapeutic strategies to reduce the severity of radiation-induced lung fibrosis (RILF), a life-threatening complication of intended or accidental ionizing radiation exposure, is a serious unmet need. We evaluated the contribution of eNAMPT (extracellular nicotinamide phosphoribosyltransferase), a damage-associated molecular pattern (DAMP) protein and TLR4 (Toll-like receptor 4) ligand, to the severity of whole-thorax lung irradiation (WTLI)-induced RILF. Wild-type (WT) and Nampt1/2 heterozygous C57BL6 mice and nonhuman primates (NHPs, Macaca mulatta) were exposed to a single WTLI dose (9.8 or 10.7 Gy for NHPs, 20 Gy for mice). WT mice received IgG1 (control) or an eNAMPTneutralizing polyclonal or monoclonal antibody (mAb) intraperitoneally 4 hours after WTLI and weekly thereafter. At 8-12 weeks after WTLI, NAMPT expression was assessed by immunohistochemistry, biochemistry, and plasma biomarker studies. RILF severity was determined by BAL protein/cells, hematoxylin and eosin, and trichrome blue staining and soluble collagen assays. RNA sequencing and bioinformatic analyses identified differentially expressed lung tissue genes/pathways. NAMPT lung tissue expression was increased in both WTLIexposed WT mice and NHPs. Nampt1/2 mice and eNAMPT polyclonal antibody/mAb-treated mice exhibited significantly attenuated WTLI-mediated lung fibrosis with reduced: 1) NAMPT and trichrome blue staining; 2) dysregulated lung tissue expression of smooth muscle actin, p-SMAD2/p-SMAD1/5/9, TGF-b, TSP1 (thrombospondin-1), NOX4, IL-1b, and NRF2; 3) plasma eNAMPT and IL-1b concentrations; and 4) soluble collagen. Multiple WTLI-induced dysregulated differentially expressed lung tissue genes/pathways with known tissue fibrosis involvement were each rectified in mice receiving eNAMPT mAbs. The eNAMPT/TLR4 inflammatory network is essentially involved in radiation pathobiology, with eNAMPT neutralization an effective therapeutic strategy to reduce RILF severity. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To assess and compare serum visfatin levels with body composition adiposity indices and glycemic control in patients with Type 2 Diabetes Mellitus (T2DM). METHODS: This observational case-control study was conducted at the Department of Physiology, College of Medicine and King Khalid University Hospital (KKUH), Riyadh, Saudi Arabia from April 2018 to March 2019. We studied sixty three individuals (33 T2DM and 30 controls) who were recruited from diabetes care clinics. Anthropometric, demographic and clinical characteristics were recorded from all participants and they were matched for age and gender. Venous blood samples were collected to measure visfatin and glycosylated hemoglobin (HbA1c). Adiposity indices were analyzed by Bio Impedance Analyzer (BIA). RESULTS: Serum visfatin levels were 7.01±3.79 ng/ml in subjects with T2DM and 4.02±2.74 ng/ml in healthy subjects (p=0.046). Body composition indices including BMI, BMR, body fat percentage [BF%], body fat mass [BFM], truncal fat [TF], truncal fat mass [TFM] and visceral fat [VF] differences were not statistically significant between two groups. Serum visfatin levels were 9.29±3.44 ng/ml in T2DM with poor glycemic control (HbA1c >7.5%) as compared to 4.24±1.87 ng/ml in diabetic patients with good glycemic control (HbA1c

Nicotinamide Adenine Dinucleotide (NAD) is an endogenous substance in redox reactions and regulates various functions in metabolism. NAD and its precursors are known for their anti-ageing and anti-obesity properties and are mainly active in the liver and muscle. Boosting NAD+ through supplementation with the precursors, such as nicotinamide mononucleotide (NMN) or nicotinamide riboside (NR), enhances insulin sensitivity and circadian rhythm in the liver, and improves mitochondrial function in the muscle. Recent evidence has revealed that the adipose tissue could be another direct target of NAD supplementation by attenuating inflammation and fat accumulation. Moreover, murine studies with genetically modified models demonstrated that nicotinamide phosphoribosyltransferase (NAMPT), a NAD regulatory enzyme that synthesizes NMN, played a critical role in lipogenesis and lipolysis in an adipocyte-specific manner. The tissue-specific effects of NAD+ metabolic pathways indicate a potential of the NAD precursors to control metabolic stress particularly via focusing on adipose tissue. Therefore, this narrative review raises an importance of NAD metabolism in white adipose tissue (WAT) through a variety of studies using different mouse models.

Kidney cancer (or renal cell carcinoma, RCC) is the sixth most common malignancy in the United States and one of the relatively few whose incidence is increasing. Because of the near universal resistance which occurs with the use of current treatment regimens, reprogrammed metabolic pathways are being investigated as potential targets for novel therapies of this disease. Borrowing from studies on other malignancies, we have identified the PAK4 and NAD biosynthetic pathways as being essential for RCC growth. We now show, using the dual PAK4/NAMPT inhibitor KPT-9274, that interference with these signaling pathways results in reduction of G2-M transit as well as induction of apoptosis and decrease in cell invasion and migration in several human RCC cell lines. Mechanistic studies demonstrate that inhibition of the PAK4 pathway by KPT-9274 attenuates nuclear β-catenin as well as the Wnt/β-catenin targets cyclin D1 and c-Myc. Furthermore, NAPRT1 downregulation, which we show occurs in all RCC cell lines tested, makes this tumor highly dependent on NAMPT for its NAD requirements, such that inhibition of NAMPT by KPT-9274 leads to decreased survival of these rapidly proliferating cells. When KPT-9274 was administered in vivo to a 786-O (VHL-mut) human RCC xenograft model, there was dose-dependent inhibition of tumor growth with no apparent toxicity; KPT-9274 demonstrated the expected on-target effects in this mouse model. KPT-9274 is being evaluated in a phase I human clinical trial in solid tumors and lymphomas, which will allow this data to be rapidly translated into the clinic for the treatment of RCC. Mol Cancer Ther; 15(9); 2119-29. ©2016 AACR.

The aim of the present study was to investigate the physiological role of nicotinamide phosphoribosyltransferase (NAMPT) associated with odontogenic differentiation during tooth development in mice. Mouse dental papilla cell-23 (MDPC-23) cells cultured in differentiation media were stimulated with the specific NAMPT inhibitor, FK866, and Visfatin (NAMPT) for up to 10 days. The cells were evaluated after 0, 4, 7, and 10 days. Cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The mineralization assay was performed by staining MDPC-23 cells with Alizarin Red S solution. After cultivation, MDPC-23 cells were harvested for quantitative PCR or Western blotting. Analysis of variance was performed using StatView 5.0 software (SAS Institute Inc., Cary, NC, USA). Statistical significance was set at p < 0.05. The expression of NAMPT increased during the differentiation of murine odontoblast-like MDPC-23 cells. Furthermore, the up-regulation of NAMPT promoted odontogenic differentiation and accelerated mineralization through an increase in representative odontoblastic biomarkers, such as dentin sialophosphoprotein, dentin matrix protein-1, and alkaline phosphatase in MDPC-23 cells. However, treatment of the cells with the NAMPT inhibitor, FK866, attenuated odontogenic differentiation, as evidenced by the suppression of odontoblastic biomarkers. These data indicate that NAMPT regulated odontoblastic differentiation through the regulation of odontoblastic biomarkers. The increase in NAMPT expression in odontoblasts was closely related to the formation of the extracellular matrix and dentin via the Runx signaling pathway. Therefore, these data suggest that NAMPT is a critical regulator of odontoblast differentiation during tooth development. [ABSTRACT FROM AUTHOR]

Nicotinamide mononucleotide (NMN) or Nicotinamide-1-ium-1-β-D-ribofuranoside 5′-phosphate is a nucleotide that can be converted into nicotinamide adenine dinucleotide (NAD) in human cells. NMN has recently attracted great attention because of its potential as an anti-aging drug, leading to great efforts for its effective manufacture. The chemical synthesis of NMN is a challenging task since it is an isomeric compound with a complicated structure. The majority of biological synthetic routes for NMN is through the intermediate phosphoribosyl diphosphate (PRPP), which is further converted to NMN by nicotinamide phosphoribosyltransferase (Nampt). There are various routes for the synthesis of PRPP from simple starting materials such as ribose, adenosine, and xylose, but all of these require the expensive phosphate donor adenosine triphosphate (ATP). Thus, an ATP regeneration system can be included, leading to diminished ATP consumption during the catalytic process. The regulations of enzymes that are not directly involved in the synthesis of NMN are also critical for the production of NMN. The aim of this review is to present an overview of the biological production of NMN with respect to the critical enzymes, reaction conditions, and productivity. [ABSTRACT FROM AUTHOR]

Objective Nicotinamide phosphoribosyltransferase (NAMPT), which is responsible for biosynthesis of nicotinamide adenine dinucleotide (NAD), has a regulatory role in cellular metabolism and thus, might be implicated in non-alcoholic fatty liver disease (NAFLD). This study aimed to show how NAMPT down-regulation in liver cells influences lipid metabolism and sirtiun 1 (SIRT1), as the main NAD-dependent deacetylase enzyme. Materials And Methods In this experimental study, HepG2 cells were transfected with NAMPT siRNA and hepatic triglyceride (TG) content and SIRT1 deacetylase activity were measured by colorimetric and fluorometric methods, respectively. Gene expression of fatty acid synthase (FAS) and sterol regulatory element-binding protein-1c (SREBP- 1c) was evaluated by real-time polymerase chain reaction (PCR). Total protein level and the phosphorylated form of acetyl-CoA carboxylase (ACC) and AMP-activated protein kinase (AMPK) were also investigated by western blotting. Results Knockdown of NAMPT significantly promoted the accumulation of TG in HepG2 cells, accompanied by a remarkable decline in SIRT1 deacetylase activity. A significant rise in the gene expression of two key lipogenic factors, FAS and SREBP-1c was also observed. These effects were also accompanied by decreased phosphorylation of ACC and AMPK. On the other hand, treatment of transfected cells with either NAD, as the SIRT1 substrate or resveratrol, as the SIRT1 activator reversed the outcomes. Conclusion These results demonstrated a protective role for NAMPT against NAFLD and its involvement in the regulation of de novo lipogenesis through the SIRT1/AMPK pathway.

Hyperthyroidism-induced cardiac disease is an evolving health, economic, and social problem affecting well-being. Sodium-glucose cotransporter protein 2 inhibitors (SGLT2-I) have been proven to be cardio-protective when administered in cases of heart failure. This study intended to investigate the potential therapeutic effect of SGLT2-I on hyperthyroidism-related cardiopulmonary injury, targeting the possible underlying mechanisms. The impact of the SGLT2-I, dapagliflozin (DAPA), (1 mg/kg/day, p.o) on LT4 (0.3 mg/kg/day, i.p)-induced cardiopulmonary injury was investigated in rats. The body weight, ECG, and serum hormones were evaluated. Also, redox balance, DNA fragmentation, inflammatory cytokines, and PCR quantification in heart and lung tissues were employed to investigate the effect of DAPA in experimentally induced hyperthyroid rats along with histological and immunohistochemical examination. Coadministration of DAPA with LT4 effectively restored all serum biomarkers to nearly average levels, improved ECG findings, and reinstated the redox balance. Also, DAPA could improve DNA fragmentation, elevate mtTFA, and lessen TNF-α and IGF-1 gene expression in both organs of treated animals. Furthermore, DAPA markedly improved the necro-inflammatory and fibrotic cardiopulmonary histological alterations and reduced the tissue immunohistochemical expression of TNF-α and caspase-3. Although further clinical and deep molecular studies are required before transposing to humans, our study emphasized DAPA's potential to relieve hyperthyroidism-induced cardiopulmonary injury in rats through its antioxidant, anti-inflammatory, and anti-apoptotic effects, as well as via antagonizing the sympathetic over activity., (© 2024. The Author(s).)

The nicotinamide phosphoribosyltransferase (NAMPT)-catalyzed substitution reaction plays a pivotal role in the biosynthesis of nucleotide compounds. However, industrial applications are hindered by the low activity of NAMPTs. In this study, a novel dual-channel protein engineering strategy was developed to increase NAMPT activity by enhancing substrate accessibility. The best mutant ( Cp NAMPT Y13G+Y15S+F76P ) with a remarkable 5-fold increase in enzyme activity was obtained. By utilizing Cp NAMPT Y13G+Y15S+F76P as a biocatalyst, the accumulation of β-nicotinamide mononucleotide reached as high as 19.94 g L -1 within 3 h with an impressive substrate conversion rate of 99.8%. Further analysis revealed that the newly generated substrate channel, formed through crack propagation, facilitated substrate binding and enhanced byproduct tolerance. In addition, three NAMPTs from different sources were designed based on the dual-channel protein engineering strategy, and the corresponding dual-channel mutants with improved enzyme activity were obtained, which proved the effectiveness and practicability of the approach.

Nicotinamide phosphoribosyltransferase (NAMPT) is the key enzyme for the synthesis of nicotinamide adenine dinucleotide (NAD) in the salvaging pathway. Though NAMPT inhibitors such as FK866 were originally developed as anti-cancer drugs, they also display neuroprotective effects. Here we show that the administration of FK866 at 0.5 mg/kg (ip, qod) for four weeks, i.e., ∼1% of the dose used for the treatment of cancer, significantly alleviates the aging-induced impairment of cognition and locomotor activity. Mechanistically, FK866 enhanced autophagy, reduced protein aggregation, and inhibited neuroinflammation indicated by decreasing TNFα, IL-6, GFAP, and Iba1 levels in the aged mouse brain. Though FK866 did not affect the total NAD and nicotinamide mononucleotide (NMN) levels in the mouse brain at the dose we used, FK866 increased nicotinamide (NAM) level in the young mouse brain and decreased NAM level in the aged mouse brain. On the other hand, FK866 did not affect the serum glucose, cholesterol, and triglyceride of young and aged mice and exhibited no effects on the various indices of young mice. Thus, the NAMPT inhibitor can be repurpose to counteract the cognitive impairment upon aging. We also envision that NAMPT inhibitor can be used for the treatment of age-related neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Objective To study the effect of total saponins of pueraria lobata (TSPL) on the differentiation of rat bone marrow mesenchymal stem cells (BMSCs) into nucleus pulposus-like cells and its mechanism. Methods An animal model of lumbar intervertebral disc degeneration in rats was established in vitro. The rats were divided into sham group, model group, 30 mg/kg TSPL treatment group and 50 mg/kg TSPL treatment group. The primary cultured rat BMSCs were divided into four groups: BMSCs group, BMSCs-TSPL (10, 20, 30, 40, 50 μmol/L) group, BMSCs-TSPL (30 μmol/L) -FK866［a specific inhibitor of nicotinamide phosphoribosyltransferase (NAMPT), 2.5 μmol/L］group and BMSCs -TSPL (30 μmol/L) - SRT2104 (a Sirt1 activator, 10 μmol/L) group. The contents of glycosaminoglycan in cells and tissues were detected by dimethylmethylene blue method, and the mRNA and protein expression levels of nucleus pulposus-like cells related genes COL2A1, Aggrecan, Sox9, Tie2 and Sirt1 were measured with RT-qPCR and Western blot assay. WST-8 method was used to detect the level of nicotinamide adenine dinucleotide (NAD+) in cells. Enzyme linked immunosorbent assay (ELISA) was used to detect the levels of adenosine triphosphate (ATP) and NAMPT, respectively. Results Compared with the sham operation group, the content of glycosaminoglycan in the intervertebral disc L5-S1 tissue was decreased in the model group (P＜0.05). Compared with the model group the content of glycosaminoglycan increased in TSPL treatment group, and the effect of 50 mg/kg TSPL treatment was better than that of 30 mg/kg treatment (P＜0.05). Compared with BMSCs group, the mRNA and protein expression levels of glycosaminoglycan, COL2A1, Aggrecan, Sox9 and Sirt1 and the contents of NAD+, ATP and NAMPT increased in TSPL group and TSPL+SRT2104 group, but the expression level of Tie2 decreased (P＜0.05). Compared with BMSCs-TSPL group, the mRNA and protein levels of COL2A1, aggrecan, Sox9 and Sirt1 and the contents of glycosaminoglycan, NAD+, ATP and NAMPT decreased after treatment with FK866, while the above indexes increased after treatment with SRT2104 (P＜0.05). Conclusion TSPL could induce BMSCs to differentiate into nucleus pulposus-like cells through the NAMPT/Sirt1 axis. [ABSTRACT FROM AUTHOR]

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BackgroundMetabolic shifts in disease are of great interest for the development of novel therapeutics. In cancer treatment, these therapies exploit the metabolic phenotype associated with oncogenesis and cancer progression. One recent strategy involves the depletion of the cofactors needed to maintain the high rate of glycolysis seen with the Warburg effect. Specifically, blocking nicotinamide adenine dinucleotide (NAD) biosynthesis via nicotinamide phosphoribosyltransferase (NAMPT) inhibition depletes cancer cells of the NAD needed for glycolysis. To characterize this metabolic phenotype in vivo and describe changes in flux with treatment, non-invasive biomarkers are necessary. One such biomarker is hyperpolarized (HP) [1-(13) C] pyruvate, a clinically translatable probe that allows real-time assessment of metabolism.MethodsWe therefore developed a cell perfusion system compatible with HP magnetic resonance (MR) and positron emission tomography (PET) to develop translatable biomarkers of response to NAMPT inhibition in reduced volume cell cultures.ResultsUsing this platform, we observed a reduction in pyruvate flux through lactate dehydrogenase with NAMPT inhibition in prostate cancer cells, and showed that both HP lactate and 2-[(18) F] fluoro-2-deoxy-D-glucose (FDG) can be used as biomarkers for treatment response of such targeted agents. Moreover, we observed dynamic flux changes whereby HP pyruvate was re-routed to alanine, providing both positive and negative indicators of treatment response.ConclusionsThis study demonstrated the feasibility of a MR/PET compatible bioreactor approach to efficiently explore cell and tissue metabolism, the understanding of which is critical for developing clinically translatable biomarkers of disease states and responses to therapeutics.

Sirtuin (Sirt) 1 and Sirt 3 are nicotinamide adenine dinucleotide ((+))-dependent protein deacetylases that are important to a number of mitochondrial-related functions; thus, identification of sirtuin activators is important. Herein, we hypothesize that pyrroloquinoline quinone (PQQ) can act as a Sirt1/Sirt3 activator. In HepG2 cell cultures, PQQ increased the expression of Sirt1 and Sirt3 gene, protein, and activity levels (P < .05). We also observed a significant increase in nicotinamide phosphoribosyltransferase gene expression (as early as 18 hours) and increased NAD(+) activity at 24 hours. In addition, targets of Sirt1 and Sirt3 (peroxisome proliferator-activated receptor γ coactivator 1α, nuclear respiratory factor 1 and 2, and mitochondrial transcription factor A) were increased at 48 hours. This is the first report that demonstrates PQQ as an activator of Sirt1 and Sirt3 expression and activity, making it an attractive therapeutic agent for the treatment of metabolic diseases and for healthy aging. Based on our study and the available data in vivo, PQQ has the potential to serve as a therapeutic nutraceutical, when enhancing mitochondrial function.

The poly-ADP-ribosylation (PARsylation) activity of tankyrase (TNKS) regulates diverse physiological processes including energy metabolism and wnt/β-catenin signaling. This TNKS activity uses NAD+ as a co-substrate to post-translationally modify various acceptor proteins including TNKS itself. PARsylation by TNKS often tags the acceptors for ubiquitination and proteasomal degradation. Whether this TNKS activity is regulated by physiological changes in NAD+ levels or, more broadly, in cellular energy charge has not been investigated. Because the NAD+ biosynthetic enzyme nicotinamide phosphoribosyltransferase (NAMPT) in vitro is robustly potentiated by ATP, we hypothesized that nutritional energy might stimulate cellular NAMPT to produce NAD+ and thereby augment TNKS catalysis. Using insulin-secreting cells as a model, we showed that glucose indeed stimulates the autoPARsylation of TNKS and consequently its turnover by the ubiquitin-proteasomal system. This glucose effect on TNKS is mediated primarily by NAD+ since it is mirrored by the NAD+ precursor nicotinamide mononucleotide (NMN), and is blunted by the NAMPT inhibitor FK866. The TNKS-destabilizing effect of glucose is shared by other metabolic fuels including pyruvate and amino acids. NAD+ flux analysis showed that glucose and nutrients, by increasing ATP, stimulate NAMPT-mediated NAD+ production to expand NAD+ stores. Collectively our data uncover a metabolic pathway whereby nutritional energy augments NAD+ production to drive the PARsylating activity of TNKS, leading to autoPARsylation-dependent degradation of the TNKS protein. The modulation of TNKS catalytic activity and protein abundance by cellular energy charge could potentially impose a nutritional control on the many processes that TNKS regulates through PARsylation. More broadly, the stimulation of NAD+ production by ATP suggests that nutritional energy may enhance the functions of other NAD+-driven enzymes including sirtuins.

NAD is mainly biosynthesized by the enzymatic action of nicotinamide phosphoribosyltransferase (NAMPT) through the salvage pathway. NAD is indispensable for the proper function and metabolism of all living cells, including cancer cells. Our previous researches revealed that inhibition of NAMPT by miRNA (miR) could suppress NAD levels and thereby hinder the growth and promotion of breast cancer (BC). Therefore, the current study was undertaken to investigate the inhibitory effects of miR-613 on NAMPT and BC cells' survival. Bioinformatics analysis and luciferase reporter assay confirmed that NAMPT 3′-untranslated region is a direct target for miR-613. The expression of miR-613 was noticed to be significantly decreased in both clinical tissue samples and BC cells by real-time PCR. Following transfection with miR-613 mimic, the expression of miR-613 was elevated in the BC cells leading to inhibition of NAMPT expression at both mRNA and protein level as measured by real-time PCR and western blotting, respectively. Inhibition of NAMPT led to a remarkable reduction in the concentration of NAD in the BC cells. The transfection also declined cell viability roughly 40% in MD Anderson-Metastatic Breast-231 (MDA-MB-231) cells. Consistently, the apoptosis rate was remarkably increased, around 65% in these cells as assayed by labeling the cells with Annexin V-fluorescein isothiocyanate (FITC) and Propidium Iodide. Targeting the NAMPT-mediated NAD salvage pathway by miR-613 is a novel approach for managing BC, which is worth further investigation. [ABSTRACT FROM AUTHOR]

Background: Retinal pigment epithelium (RPE) cellular senescence is an important process in degenerative retinal disorders. Grape seed proanthocyanidin extract (GSPE) alleviates senescence-related degenerative disorders; however, the potential effects of GSPE intake on RPE cellular senescence through regulating NAMPT/SIRT1/NLRP3 pathway remain unclear. Methods: The effects of GSPE on NAMPT expression and NAD+ contents were detected with Western blot and assay kit in both in-vivo and in-vitro AMD models. Senescence-related biomarkers, including p16, p21 expressions and β-gal staining, were conducted in different groups. The protective effects of GSPE treatment on the mitochondrial homeostasis and barrier function of RPE cells were detected using mtDNA lesions analyses, JC-1 staining, ZO1 staining and trans-epithelial cell resistance (TEER) detection. The expression of senescence-associated secretory phenotype (SASP) in different groups would be conducted with qPCR. To demonstrate the potential effects of NAMPT/SIRT1/NLRP3 pathway after GSPE treatment, the protein levels of relevant key regulators after applications of NAMPT inhibitor, Fk866, and SIRT1 inhibitor, EX-527. Results: GSPE significantly improves the NAMPT expression and NAD+ content in aging mice, and thus alleviates the RPE cellular senescence. In advanced in-vitro studies, GSPE significantly up-regulated NAMPT content and thus relieved H2O2 induced NAD+ depression through analyzing the NAD+ contents in different groups. In advanced analyses, it was reported that GSPE could alleviate mitochondrial permeability, mtDNA damage, ZO1 expression and SASP levels in aging RPE cells. Thus, GSPE treatment significantly decreased senescence-related protein p16 and p21, as well as SASP levels in in-vitro aging model, and it was demonstrated that GSPE could illustrate a significant anti-aging effect. The Western blot data in GSPE treatment of aging RPE cells demonstrated that GSPE could significantly improve NAMPT and SIRT1 levels, and thus depressed NLRP3 expression. Conclusion: This study indicated that GSPE alleviated RPE cellular senescence through NAMPT/SIRT1/NLRP3 pathway. This study highlighted the potential effects of GSPE on degenerative retinopathy through the crosstalk of NAD+ metabolism, SIRT1 function and NLRP3 activation. [ABSTRACT FROM AUTHOR]

We recently demonstrated that cancer cells that recover from damage exhibit increased aerobic glycolysis, however, the molecular mechanism by which cancer cells survive the damage and show increased aerobic glycolysis remains unknown. Here, we demonstrate that diverse cancer cells that survive hypoxic or oxidative damage show rapid cell proliferation, and develop tolerance to damage associated with increased production of hydrogen sulfide (H2S) which drives up-regulation of nicotinamide phosphoribosyltransferase (Nampt). Consistent with existence of a H2S-Nampt energetic circuit, in damage recovered cancer cells, H2S, Nampt and ATP production exhibit a significant correlation. Moreover, the treatment of cancer cells with H2S donor, NaHS, coordinately increases Nampt and ATP levels, and protects cells from drug induced damage. Inhibition of cystathionine beta synthase (CBS) or cystathionase (CTH), enzymes which drive generation of H2S, decreases Nampt production while suppression of Nampt pathway by FK866, decreases H2S and ATP levels. Damage recovered cells isolated from tumors grown subcutaneously in athymic mice also show increased production of H2S, Nampt and ATP levels, associated with increased glycolysis and rapid proliferation. Together, these data show that upon recovery from potential lethal damage, H2S-Nampt directs energy expenditure and aerobic glycolysis in cancer cells, leads to their exponential growth, and causes a high degree of tolerance to damage. Identification of H2S-Nampt as a pathway responsible for induction of damage tolerance in cancer cells may underlie resistance to therapy and offers the opportunity to target this pathway as a means in treatment of cancer.