Nicotinamide phosphoribosyltransferase prompts bleomycin-induced pulmonary fibrosis by driving macrophage M2 polarization in mice.

Rationale: Idiopathic pulmonary fibrosis (IPF) is an irreversible, fatal interstitial lung disease lacking specific therapeutics. Nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme of the nicotinamide adenine dinucleotide (NAD) salvage biosynthesis pathway and a cytokine, has been previously reported as a biomarker for lung diseases; however, the role of NAMPT in pulmonary fibrosis has not been elucidated. Methods: We identified the NAMPT level changes in pulmonary fibrosis by analyzing public RNA-Seq databases, verified in collected clinical samples and mice pulmonary fibrosis model by Western blotting, qRT-PCR, ELISA and Immunohistochemical staining. We investigated the role and mechanism of NAMPT in lung fibrosis by using pharmacological inhibition on NAMPT and Nampt transgenic mice. In vivo macrophage depletion by clodronate liposomes and reinfusion of IL-4-induced M2 bone marrow-derived macrophages (BMDMs) from wild-type mice, combined with in vitro cell experiments, were performed to further validate the mechanism underlying NAMPT involving lung fibrosis. Results: We found that NAMPT increased in the lungs of patients with IPF and mice with bleomycin (BLM)-induced pulmonary fibrosis. NAMPT inhibitor FK866 alleviated BLM-induced pulmonary fibrosis in mice and significantly reduced NAMPT levels in bronchoalveolar lavage fluid (BALF). The lung single-cell RNA sequencing showed that NAMPT expression in monocytes/macrophages of IPF patients was much higher than in other lung cells. Knocking out NAMPT in mouse monocytes/macrophages (Namptfl/fl;Cx3cr1CreER) significantly alleviated BLM-induced pulmonary fibrosis in mice, decreased NAMPT levels in BALF, reduced the infiltration of M2 macrophages in the lungs and improved mice survival. Depleting monocytes/macrophages in Namptfl/fl;Cx3cr1CreER mice by clodronate liposomes and subsequent pulmonary reinfusion of IL-4-induced M2 BMDMs from wild-type mice, reversed the protective effect of monocyte/macrophage NAMPT-deletion on lung fibrosis. In vitro experiments confirmed that the mechanism of NAMPT engaged in pulmonary fibrosis is related to the released NAMPT by macrophages promoting M2 polarization in a non-enzyme-dependent manner by activating the STAT6 signal pathway. Conclusions: NAMPT prompts bleomycin-induced pulmonary fibrosis by driving macrophage M2 polarization in mice. Targeting the NAMPT of monocytes/macrophages is a promising strategy for treating pulmonary fibrosis.

Status of visfatin in female reproductive function under normal and pathological conditions: a mini review.

Adipokines are now well-known to regulate reproduction. Visfatin is an adipokine expressed in the hypothalamus, pituitary, ovary, uterus, and placenta of different species, and since it has been found to modulate the endocrine secretion of the hypothalamus, pituitary gland and ovary, it may be considered a novel regulator of female reproduction. Although the majority of the literature explored its role in ovarian regulation, visfatin has also been shown to regulate uterine remodeling, endometrial receptivity and embryo development, and its expression in the uterus is steroid dependent. Like other adipokines, visfatin expression and levels are deregulated in pathological conditions including polycystic ovary syndrome. Thus, the present mini-review focuses on the role of visfatin in female reproduction under both physiological and pathological conditions.

Discovery of potent and novel dual NAMPT/BRD4 inhibitors for efficient treatment of hepatocellular carcinoma.

The NAPRT-induced increase in NAD+ levels was proposed as a mechanism contributing to hepatocellular carcinoma (HCC) resistance to NAMPT inhibitors. Thus, concurrently targeting NAMPT and NAPRT could be considered to overcome drug resistance. A BRD4 inhibitor downregulates the expression of NAPRT in HCC, and the combination of NAMPT inhibitors with BRD4 inhibitors simultaneously blocks NAD+ generation via salvage and the PH synthesis pathway. Moreover, the combination of the two agents significantly downregulated the expression of tumor-promoting genes and strongly promoted apoptosis. The present work identified various NAMPT/BRD4 dual inhibitors based on the multitargeted drug rationale. Among them, compound A2, which demonstrated the strongest effect, exhibited potent inhibition of NAMPT and BRD4 (IC50 = 35 and 58 nM, respectively). It significantly suppressed the growth and migration of HCC cells and facilitated their apoptosis. Furthermore, compound A2 also manifested a robust anticancer effect in HCCLM3 xenograft mouse models, with no apparent toxic effects. Our findings in this study provide an effective approach to target NAD+ metabolism for HCC treatment.

Expression of visfatin in gingival crevicular fluid and gingival tissues in different periodontal conditions: a cross-sectional study.

BACKGROUND: Studies have shown that visfatin is an inflammatory factor closely related to periodontitis. We examined the levels of visfatin in gingival crevicular fluid (GCF) and gingival tissues under different periodontal conditions, in order to provide more theoretical basis for exploring the role of visfatin in the pathogenesis of periodontitis. METHODS: We enrolled 87 subjects, with 43 in the chronic periodontitis (CP) group, 21 in the chronic gingivitis (CG) group, and 23 in the periodontal health (PH) group. Periodontal indexes (PD, AL, PLI, and BI) were recorded. GCF samples were collected for visfatin quantification, and gingival tissues were assessed via immunohistochemical staining. RESULTS: Visfatin levels in GCF decreased sequentially from CP to CG and PH groups, with statistically significant differences (P < 0.05). The CP group exhibited the highest visfatin levels, while the PH group had the lowest. Gingival tissues showed a similar trend, with significant differences between groups (P < 0.001). Periodontal indexes were positively correlated with visfatin levels in both GCF and gingival tissues (P < 0.001). A strong positive correlation was observed between visfatin levels in GCF and gingival tissues (rs = 0.772, P < 0.001). CONCLUSION: Greater periodontal destruction corresponded to higher visfatin levels in GCF and gingival tissues, indicating their potential collaboration in damaging periodontal tissues. Visfatin emerges as a promising biomarker for periodontitis and may play a role in its pathogenesis.

Design of FK866-Based Degraders for Blocking the Nonenzymatic Functions of Nicotinamide Phosphoribosyltransferase.

Nicotinamide phosphoribosyltransferase (NAMPT) is an attractive therapeutic target for treating select cancers. There are two forms of NAMPT: intracellular NAMPT (iNAMPT, the rate-limiting enzyme in the mammalian NAD+ main synthetic pathway) and extracellular NAMPT (eNAMPT, a cytokine with protumorigenic function). Reported NAMPT inhibitors only inhibit iNAMPT and show potent activities in preclinical studies. Unfortunately, they failed to show efficacy due to futility and toxicity. We developed a series of FK866-based NAMPT-targeting PROTACs and identified LYP-8 as a potent and effective NAMPT degrader that simultaneously diminished iNAMPT and eNAMPT. Importantly, LYP-8 demonstrated superior efficacy and safety in mice when compared to the clinical candidate, FK866. This study highlights the importance and feasibility of applying PROTACs as a superior strategy for interfering with both the enzymatic function of NAMPT (iNAMPT) and nonenzymatic function of NAMPT (eNAMPT), which is difficult to achieve with conventional NAMPT inhibitors.

An oncolytic HSV-1 armed with Visfatin enhances antitumor effects by remodeling tumor microenvironment against murine pancreatic cancer.

Oncolytic viruses (OVs) have shown potential in converting a "cold" tumor into a "hot" one and exhibit effectiveness in various cancer types. However, only a subset of patients respond to oncolytic virotherapy. It is important to understand the resistance mechanisms to OV treatment in pancreatic ductal adenocarcinoma (PDAC) to engineer oncolytic viruses. In this study, we used transcriptome RNA sequencing (RNA-seq) to identify Visfatin, which was highly expressed in the responsive tumors following OV treatment. To explore the antitumor efficacy, we modified OV-mVisfatin, which effectively inhibited tumor growth. For the first time, we revealed that Visfatin promoted the antitumor efficacy of OV by remodeling the tumor microenvironment, which involved enhancing CD8+ T cell and DC cell infiltration and activation, repolarizing macrophages towards the M1-like phenotype, and decreasing Treg cells using single-cell RNA sequencing (scRNA-seq) and flow cytometry. Furthermore, PD-1 blockade significantly enhanced OV-mVisfatin antitumor efficacy, offering a promising new therapeutic strategy for PDAC.

Association between visfatin and periodontitis: a systematic review and meta-analysis.

Background: Periodontitis is a chronic inflammatory disease caused by bacterial infection in the periodontal support tissue. Visfatin, a hormone secreted mainly by adipocytes and macrophages, plays an important role in immune regulation and defense. Although studies have indicated that patients with periodontitis have significantly high serum and gingival crevicular fluid levels of visfatin, the relationship between this adipocytokine and periodontal disease remains unclear. Aim: The aim of this study was to systematically evaluate the association between visfatin levels and periodontitis. Methods: The PubMed, Web of Science, ScienceDirect, EBSCO, and Wiley Online Library databases were searched for potential studies, using "periodontitis" and "visfatin" as the keywords in the title and abstract search fields. Standardized mean difference (SMD) values with corresponding 95% confidence intervals (CIs) were determined from the results of this meta-analysis. Results: In total, 22 articles involving 456 patients with periodontitis and 394 healthy individuals (controls) were included in the meta-analysis. Visfatin levels were significantly higher in the patients with periodontitis than in the healthy individuals (SMD: 3.82, 95% CI [3.01-4.63]). Moreover, the visfatin levels were significantly lowered after periodontitis treatment (SMD: -2.29, 95% CI [-3.33 to -1.26]). Conclusion: This first-ever meta-analysis comparing visfatin levels between patients with periodontitis and healthy individuals suggests that this adipocytokine can be a diagnostic and therapeutic biomarker for periodontal disease.

Zebrafish nampt-a mutants are viable despite perturbed primitive hematopoiesis.

BACKGROUND: Nicotinamide phosphoribosyltransferase (Nampt) is required for recycling NAD+ in numerous cellular contexts. Morpholino-based knockdown of zebrafish nampt-a has been shown to cause abnormal development and defective hematopoiesis concomitant with decreased NAD+ levels. However, surprisingly, nampt-a mutant zebrafish were recently found to be viable, suggesting a discrepancy between the phenotypes in knockdown and knockout conditions. Here, we address this discrepancy by directly comparing loss-of-function approaches that result in identical defective transcripts in morphants and mutants. RESULTS: Using CRISPR/Cas9-mediated mutagenesis, we generated nampt-a mutant lines that carry the same mis-spliced mRNA as nampt-a morphants. Despite reduced NAD+ levels and perturbed expression of specific blood markers, nampt-a mutants did not display obvious developmental defects and were found to be viable. In contrast, injection of nampt-a morpholinos into wild-type or mutant nampt-a embryos caused aberrant phenotypes. Moreover, nampt-a morpholinos caused additional reduction of blood-related markers in nampt-a mutants, suggesting that the defects observed in nampt-a morphants can be partially attributed to off-target effects of the morpholinos. CONCLUSIONS: Our findings show that zebrafish nampt-a mutants are viable despite reduced NAD+ levels and a perturbed hematopoietic gene expression program, indicating strong robustness of primitive hematopoiesis during early embryogenesis.

Effect of NAMPT on the proliferation and apoptosis in odontoblast-like MDPC-23 cell.

This study aimed to evaluate the physiological role of NAMPT associated with MDPC-23 odontoblast cell proliferation. Cell viability was measured using the (DAPI) staining, caspase activation analysis and immunoblotting were performed. Visfatin promoted MDPC-23 odontoblast cell growth in a dose-dependent manner. Furthermore, the up-regulation of Visfatin promoted odontogenic differentiation and accelerated mineralization through an increase in representative odontoblastic biomarkers in MDPC-23 cells. However, FK-866 cell growth in a dose-dependent manner induced nuclear condensation and fragmentation. FK-866-treated cells showed H&E staining and increased apoptosis compared to control cells. The expression of anti-apoptotic factors components of the mitochondria-dependent intrinsic apoptotic pathway significantly decreased following FK-866 treatment. The expression of pro-apoptotic increased upon FK-866 treatment. In addition, FK-866 activated caspase-3 and PARP to induce cell death. In addition, after treating FK-866 for 72 h, the 3/7 activity of MDPC-23 cells increased in a concentration-dependent manner, and the IHC results also confirmed that Caspase-3 increased in a concentration-dependent. Therefore, the presence or absence of NAMPT expression in dentin cells was closely related to cell proliferation and formation of extracellular substrates.

Channeling Nicotinamide Phosphoribosyltransferase (NAMPT) to Address Life and Death.

Nicotinamide phosphoribosyltransferase (NAMPT) catalyzes the rate-limiting step in NAD+ biosynthesis via salvage of NAM formed from catabolism of NAD+ by proteins with NADase activity (e.g., PARPs, SIRTs, CD38). Depletion of NAD+ in aging, neurodegeneration, and metabolic disorders is addressed by NAD+ supplementation. Conversely, NAMPT inhibitors have been developed for cancer therapy: many discovered by phenotypic screening for cancer cell death have low nanomolar potency in cellular models. No NAMPT inhibitor is yet FDA-approved. The ability of inhibitors to act as NAMPT substrates may be associated with efficacy and toxicity. Some 3-pyridyl inhibitors become 4-pyridyl activators or "NAD+ boosters". NAMPT positive allosteric modulators (N-PAMs) and boosters may increase enzyme activity by relieving substrate/product inhibition. Binding to a "rear channel" extending from the NAMPT active site is key for inhibitors, boosters, and N-PAMs. A deeper understanding may fulfill the potential of NAMPT ligands to regulate cellular life and death.

Nicotinamide phosphoribosyltransferase modulates PD-L1 in bladder cancer and enhances immunotherapeutic sensitivity.

Bladder cancer (BLCA) is one of the most prevalent malignancies worldwide with a high mortality rate and poor response to immunotherapy in patients expressing lower programmed death ligand 1 (PD-L1) levels. Nicotinamide phosphoribosyltransferase (NAMPT), a rate-limiting enzyme responsible for the biosynthesis of nicotinamide adenine dinucleotide (NAD+) from nicotinamide was reported to be overexpressed in various cancers; however, the role of NAMPT in BLCA is obscure. Immunohistochemistry of tissue microarrays, a real-time polymerase chain reaction, Western blotting, proliferation assay, NAD+ quantification, transwell-migration assay, and colony-formation assay were performed to measure NAMPT and PD-L1 expression levels in patients and the effect of NAMPT inhibition on T24 cells. Our study revealed that NAMPT expression was upregulated in BLCA patients with different grades and associated with poor T-cell infiltration. Notably, FK866-mediated NAMPT inhibition decreased cell viability by depleting NAD+, and reducing the migration ability and colony-formation ability of T24 cells. Interestingly, NAMPT negatively regulated PD-L1 under an interferon (IFN)-γ-mediated microenvironment. However, exogenous NAMPT activator has no effect on PD-L1. NAD+ supplementation also only increased PD-L1 in the absence of IFN-γ. Conclusively, NAMPT is crucial for BLCA tumorigenic properties, and it regulates expression of the PD-L1 immune checkpoint protein. NAMPT could be considered a target for modulating sensitivity to immunotherapy.

Unlocking the Dietary Puzzle: How Macronutrient Intake Shapes the Relationship between Visfatin and Atherosclerosis in Type 2 Diabetes.

Background and Objectives. Optimal nutrition for type 2 diabetes (T2DM) aims to improve glycemic control by promoting weight loss and reducing adipose tissue, consequently improving cardiovascular health. Dietary alterations can influence adipose tissue metabolism and potentially impact adipocytokines like visfatin, thereby affecting atherosclerosis development. This study aimed to investigate dietary habits and adherence to recommendations among individuals with T2DM and to examine how dietary adherence influences the association between visfatin and subclinical atherosclerosis. Materials and Methods: This cross-sectional multicenter study involved 216 adults (30-70 years) with T2DM, assessing dietary habits, adherence to recommendations (carbohydrates, fats, protein, fiber, saturated fatty acid, polyunsaturated and monounsaturated fatty acid (PUFA and MUFA) and salt), and the association between visfatin and subclinical atherosclerosis. Participants completed 24 h dietary recalls; dietary misreporting was assessed using the Goldberg cut-off method. Carotid intima-media thickness (IMT) and plaque occurrence were evaluated with ultrasound, while visfatin levels were measured using Luminex's xMAP technology. Results: Three of the eight recommendations were followed in 31% of subjects, two in 26%, and four in 20%, with the highest adherence to MUFA and protein intake. Significant correlations between IMT and visfatin were observed in individuals with specific dietary patterns. The association between IMT and visfatin persisted when PUFA and MUFA intake aligned with recommendations. PUFA intake ≤ 10% and MUFA ≤ 20% of total energy significantly correlated with carotid artery IMT (p = 0.010 and p = 0.006, respectively). Visfatin's associations with IMT remained significant (p = 0.006) after adjusting for common risk factors, medication use, and dietary nonadherence. No association was observed with carotid artery plaque. Conclusions: Dietary compliance was limited, as only 31% adhered even to three of eight recommendations. A common dietary pattern characterized by low carbohydrate and fiber but high fat, total fat, saturated fat, and salt intake was identified. This pattern amplifies the statistical association between visfatin and subclinical atherosclerosis.

Relationship between serum apelin, visfatin levels, and body composition in Polycystic Ovary Syndrome patients.

OBJECTIVE: To investigate the relationship between body composition and serum visfatin and apelin levels in patients with polycystic ovary syndrome (PCOS). METHODS: In this prospective observational study, the differences in body composition, levels of gonadal hormone concentrations, glucose metabolism, apelin, and visfatin were compared between PCOS patients and the control group. PCOS patients were further divided into different subgroups according to different obesity criteria and the differences between serum visfatin and apelin levels in different subgroups were compared. Finally, the correlation of serum visfatin levels and apelin levels with body composition, and metabolism-related indicators in PCOS patients was explored. RESULTS: A total collected 178 cases of PCOS patients and 172 cases of healthy women (control group) between 2020 July and 2021 November. In PCOS patients, their weight, Body Mass Index (BMI), Waist Hip Rate (WHR), Fat-Free Mass Index (FFMI), Percent Body Fat (PBF), Fat mass index (FMI), PBF of Arm, PBF of Leg, PBF of the Trunk, Visceral Fat Level (VFL), fasting insulin (FINS), Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) and Luteinizing hormone (LH) were significantly higher than in the control group (all P < 0.001), Percent Skeletal Muscle (PSM), PSM of Leg, and PSM of the Trunk were significantly decreased than in the control group (all P < 0.001). The PCOS patients had significantly higher serum visfatin levels and apelin levels compared with the control group (all P < 0.001). In PBF > 35 % PCOS patients, the apelin and visfatin levels were significantly higher than the PBF ≤ 35 % PCOS patients. In WHR ≥ 0.85 and BMI ≥ 24 kg/m2 PCOS patients, the visfatin levels were significantly higher than the WHR < 0.85 and BMI < 24 kg/m2 PCOS patients. Serum apelin and visfatin positively correlated with BMI level, WHR, FFMI, PBF, FMI, PBF of arms, PBF of legs, PBF of the trunk, VFL, FBG, HOMA-IR index and negatively correlated with PSM, PSM of legs, and PSM of the trunk (all P < 0.001). CONCLUSIONS: Compared with healthy women, Patients with PCOS have an increased fat content in various parts of the body, reduced skeletal muscle content, and are often complicated by metabolic abnormalities. Serum visfatin and apelin correlated not only with obesity, fat mass, and fat distribution but also with muscle mass and distribution. It may be possible to reduce the long-term risk of metabolic disease in PCOS through the monitoring and management of the body composition in PCOS patients or to reflect the therapeutic effect of PCOS.

NAMPT/NAD+/PARP1 Pathway Regulates CFA-Induced Inflammatory Pain via NF-κB Signaling in Rodents.

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-1ß 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-1ß inflammatory pathway.

Structural insights into Xanthomonas campestris pv. campestris NAD+ biosynthesis via the NAM salvage pathway.

Nicotinamide phosphoribosyltransferase (NAMPT) plays an important role in the biosynthesis of nicotinamide adenine dinucleotide (NAD+) via the nicotinamide (NAM) salvage pathway. While the structural biochemistry of eukaryote NAMPT has been well studied, the catalysis mechanism of prokaryote NAMPT at the molecular level remains largely unclear. Here, we demonstrated the NAMPT-mediated salvage pathway is functional in the Gram-negative phytopathogenic bacterium Xanthomonas campestris pv. campestris (Xcc) for the synthesis of NAD+, and the enzyme activity of NAMPT in this bacterium is significantly higher than that of human NAMPT in vitro. Our structural analyses of Xcc NAMPT, both in isolation and in complex with either the substrate NAM or the product nicotinamide mononucleotide (NMN), uncovered significant details of substrate recognition. Specifically, we revealed the presence of a NAM binding tunnel that connects the active site, and this tunnel is essential for both catalysis and inhibitor binding. We further demonstrated that NAM binding in the tunnel has a positive cooperative effect with NAM binding in the catalytic site. Additionally, we discovered that phosphorylation of the His residue at position 229 enhances the substrate binding affinity of Xcc NAMPT and is important for its catalytic activity. This work reveals the importance of NAMPT in bacterial NAD+ synthesis and provides insights into the substrate recognition and the catalytic mechanism of bacterial type II phosphoribosyltransferases.

Role of the intracerebroventricular injection of the visfatin and its interaction with neuropeptide Y and nitric systems on food intake in neonatal chicken.

Visfatin play an essential role in the central regulation of appetite in birds. This study aimed to determine role of intracerebroventricular (ICV) injection of the visfatin on food intake and its possible interaction with neuropeptide Y (NPY) and nitric oxide system in neonatal broiler chicken. In experiment 1, neonatal chicken received ICV injection visfatin (1, 2 and 4 µg). In experiment 2, chicken received ICV injection of B5063 (NPY1 receptor antagonist 1.25 µg), visfatin (4 µg) and co-injection of the B5063 + Visfatin. In experiments 3-6, SF22 (NPY2 receptor antagonist 1.25 µg), SML0891 (NPY5 receptor antagonist 1.25 µg), L-NAME (nitric oxide synthase inhibitor, 100 nmol) and L-arginine (Precursor of nitric oxide, 200 nmol) were injected instead of B5063. Then the amount of cumulative food was measured at 30, 60 and 120 min after injection. Obtained data showed, injection visfatin (2 and 4 µg) increased food intake compared to control group (P < 0.05). Co-injection of the B5063 + Visfatin decreased visfatin-induced hyperphagia compared to control group (P < 0.05). Co-injection of the L-NAME + Visfatin amplified visfatin-induced hyperphagia compared to control group (P < 0.05). The result showed that visfatin has hyperphagic role and this effect mediates via NPY1 and nitric oxide system in neonatal chicken.

Dual-inhibition of NAMPT and PAK4 induces anti-tumor effects in 3D-spheroids model of platinum-resistant ovarian cancer.

Ovarian cancer follows a characteristic progression pattern, forming multiple tumor masses enriched with cancer stem cells (CSCs) within the abdomen. Most patients develop resistance to standard platinum-based drugs, necessitating better treatment approaches. Targeting CSCs by inhibiting NAD+ synthesis has been previously explored. Nicotinamide phosphoribosyltransferase (NAMPT), which is the rate limiting enzyme in the salvage pathway for NAD+ synthesis is an attractive drug target in this pathway. KPT-9274 is an innovative drug targeting both NAMPT and p21 activated kinase 4 (PAK4). However, its effectiveness against ovarian cancer has not been validated. Here, we show the efficacy and mechanisms of KPT-9274 in treating 3D-cultured spheroids that are resistant to platinum-based drugs. In these spheroids, KPT-9274 not only inhibited NAD+ production in NAMPT-dependent cell lines, but also suppressed NADPH and ATP production, indicating reduced mitochondrial function. It also downregulated of inflammation and DNA repair-related genes. Moreover, the compound reduced PAK4 activity by altering its mostly cytoplasmic localization, leading to NAD+-dependent decreases in phosphorylation of S6 Ribosomal protein, AKT, and ß-Catenin in the cytoplasm. These findings suggest that KPT-9274 could be a promising treatment for ovarian cancer patients who are resistant to platinum drugs, emphasizing the need for precision medicine to identify the specific NAD+ producing pathway that a tumor relies upon before treatment.

NAMPT-Driven M2 Polarization of Tumor-Associated Macrophages Leads to an Immunosuppressive Microenvironment in Colorectal Cancer.

Nicotinamide phosphoribosyltransferase (NAMPT) is a metabolic enzyme with key roles in inflammation. Previous studies have examined the consequences of its upregulated expression in cancer cells themselves, but studies are limited with respect to its role in the other cells within the tumor microenvironment (TME) during colorectal cancer (CRC) progression. Using single-cell RNA sequencing (scRNA-seq) data, it is founded that NAMPT is highly expressed in SPP1+ tumor-associated macrophages (TAMs), a unique subset of TAMs associated with immunosuppressive activity. A NAMPThigh gene signature in SPP1+ TAMs correlated with worse prognostic outcomes in CRC patients. The effect of Nampt deletion in the myeloid compartment of mice during CRC development is explored. NAMPT deficiency in macrophages resulted in HIF-1α destabilization, leading to reduction in M2-like TAM polarization. NAMPT deficiency caused significant decreases in the efferocytosis activity of macrophages, which enhanced STING signaling and the induction of type I IFN-response genes. Expression of these genes contributed to anti-tumoral immunity via potentiation of cytotoxic T cell activity in the TME. Overall, these findings suggest that NAMPT-initiated TAM-specific genes can be useful in predicting poor CRC patient outcomes; strategies aimed at targeting NAMPT may provide a promising therapeutic approach for building an immunostimulatory TME in CRC progression.

Discovery of a Potent Nicotinamide Phosphoribosyltransferase Activator for Improving Aging-associated Dysfunctions.

Nicotinamide adenine dinucleotide (NAD+) plays a crucial role in the cellular energy metabolism pathway. Nicotinamide phosphoribosyltransferase (NAMPT) is a rate-limiting enzyme involved in the biosynthesis of NAD+. Herein, a series of new NAMPT activators were designed to increase the NAD+ levels and improve aging-associated dysfunctions. In particular, compound C8 effectively activated NAMPT and promoted the biosynthesis of NAD+. Furthermore, we demonstrated that NAMPT activator C8 possessed excellent antiaging effects both in vitro and in vivo. Activator C8 showed potent activity in delaying aging in senescent HL-7702 cells and extended the lifespan of Caenorhabditis elegans. In a naturally aging mouse model, compound C8 effectively alleviated age-related dysfunctions and markers. Therefore, NAMPT activator C8 represented a promising lead compound for the treatment of age-related diseases.

[Mechanism and Clinical Significance of NAMPT in Multiple Myeloma].

OBJECTIVE: To investigate the mechanism and clinical value of nicotinamide phosphoribosyltransferase (NAMPT) in multiple myeloma (MM). METHODS: RT-qPCR and Western blot were used to detect the expression of NAMPT in MM cells and normal bone marrow mononuclear cells. The biological function of NAMPT was analyzed by cell proliferation and apoptosis assay, small interfering RNA silencing, overexpression assay and chromatin immunoprecipitation assay. RESULTS: The mRNA and protein expression levels of NAMPT in MM cell lines (MM1R, MM1S, U266 and RPMI-8226) were significantly higher than those in normal bone marrow mononuclear cells (P < 0.001), and were most obvious in U266 cells. Compared with Si-NC group, the proliferation of U266 cells in Si-NAMPT group was significantly inhibited at 24, 48 and 72 h after transfection (P =0.006, P < 0.001, P =0.001), and the apoptosis rate of U266 cells was significantly increased at 48 h after transfection (P < 0.001). Compared with Flag-NC group, U266 cell proliferation in Flag-NAMPT group was significantly increased (P =0.003, P =0.002, P < 0.001), while the apoptosis rate decreased significantly at 48 h after transfection. The expression of NAMPT in U266 cells was regulated by XBP1 at transcriptional level. The proliferation rate of U266 cells with XBP1 or NAMPT stable knockout or MKC3946 pretreated with bortezomib was significantly decreased, the levels of BCL-2 mRNA and protein were also significantly decreased, while the levels of BAX mRNA and protein were significantly increased, moreover, the cleavage degree of caspase-3 significantly decreased, while caspase-3/7 activity increased dramatically (P < 0.05). CONCLUSIONS: The high expression of NAMPT in MM cell line can promote MM cell proliferation and inhibit apoptosis. NAMPT is regulated by IRE1α-XBP1 signaling pathway in U266 cells. Stable knockdown of NAMPT or blocking of IRE1α-XBP1 pathway can significantly increase the sensitivity of U266 cells to bortezomib.