Cloning and characterization of the cDNA encoding a novel human pre-B-cell colony-enhancing factor

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.

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.

Exercise training upregulates intracellular nicotinamide phosphoribosyltransferase expression in humans: a systematic review with meta-analysis

Objective

Aging 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.

Methods

We 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.

Results

The 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.

Conclusion

Exercise 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.

Extracellular nicotinamide phosphoribosyltransferase: role in disease pathophysiology and as a biomarker

Nicotinamide phosphoribosyltransferase (NAMPT) plays a central role in mammalian cell metabolism by contributing to nicotinamide adenine dinucleotide biosynthesis. However, NAMPT activity is not limited to the intracellular compartment, as once secreted, the protein accomplishes diverse functions in the extracellular space. Extracellular NAMPT (eNAMPT, also called visfatin or pre-B-cell colony enhancing factor) has been shown to possess adipocytokine, pro-inflammatory, and pro-angiogenic activities. Numerous studies have reported the association between elevated levels of circulating eNAMPT and various inflammatory and metabolic disorders such as obesity, diabetes, atherosclerosis, arthritis, inflammatory bowel disease, lung injury and cancer. In this review, we summarize the current state of knowledge on eNAMPT biology, proposed roles in disease pathogenesis, and its potential as a disease biomarker. We also briefly discuss the emerging therapeutic approaches for eNAMPT inhibition.

Role of adipokines in sarcopenia

ABSTRACT

Sarcopenia is an age-related disease that mainly involves decreases in muscle mass, muscle strength and muscle function. At the same time, the body fat content increases with aging, especially the visceral fat content. Adipose tissue is an endocrine organ that secretes biologically active factors called adipokines, which act on local and distant tissues. Studies have revealed that some adipokines exert regulatory effects on muscle, such as higher serum leptin levels causing a decrease in muscle function and adiponectin inhibits the transcriptional activity of Forkhead box O3 (FoxO3) by activating peroxisome proliferators-activated receptor-γ coactivator -1α (PGC-1α) and sensitizing cells to insulin, thereby repressing atrophy-related genes (atrogin-1 and muscle RING finger 1 [MuRF1]) to prevent the loss of muscle mass. Here, we describe the effects on muscle of adipokines produced by adipose tissue, such as leptin, adiponectin, resistin, mucin and lipocalin-2, and discuss the importance of these adipokines for understanding the development of sarcopenia.

Shared biological mechanisms of depression and obesity: focus on adipokines and lipokines

Depression and obesity are both common disorders currently affecting public health, frequently occurring simultaneously within individuals, and the relationship between these disorders is bidirectional. The association between obesity and depression is highly co-morbid and tends to significantly exacerbate metabolic and related depressive symptoms. However, the neural mechanism under the mutual control of obesity and depression is largely inscrutable. This review focuses particularly on alterations in systems that may mechanistically explain the in vivo homeostatic regulation of the obesity and depression link, such as immune-inflammatory activation, gut microbiota, neuroplasticity, HPA axis dysregulation as well as neuroendocrine regulators of energy metabolism including adipocytokines and lipokines. In addition, the review summarizes potential and future treatments for obesity and depression and raises several questions that need to be answered in future research. This review will provide a comprehensive description and localization of the biological connection between obesity and depression to better understand the co-morbidity of obesity and depression.

Mechanism of Allosteric Modulation of Nicotinamide Phosphoribosyltransferase to Elevate Cellular NAD. Biochemistry 2023;62:923-933. [PMID: 36746631 DOI: 10.1021/acs.biochem.2c00655]

In aging and disease, cellular nicotinamide adenine dinucleotide (NAD+) is depleted by catabolism to nicotinamide (NAM). NAD+ supplementation is being pursued to enhance human healthspan and lifespan. Activation of nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting step in NAD+ biosynthesis, has the potential to increase the salvage of NAM. Novel NAMPT-positive allosteric modulators (N-PAMs) were discovered in addition to the demonstration of NAMPT activation by biogenic phenols. The mechanism of activation was revealed through the synthesis of novel chemical probes, new NAMPT co-crystal structures, and enzyme kinetics. Binding to a rear channel in NAMPT regulates NAM binding and turnover, with biochemical observations being replicated by NAD+ measurements in human cells. The mechanism of action of N-PAMs identifies, for the first time, the role of the rear channel in the regulation of NAMPT turnover coupled to productive and nonproductive NAM binding. The tight regulation of cellular NAMPT via feedback inhibition by NAM, NAD+, and adenosine 5'-triphosphate (ATP) is differentially regulated by N-PAMs and other activators, indicating that different classes of pharmacological activators may be engineered to restore or enhance NAD+ levels in affected tissues.

Interaction Between Adipocytes and B Lymphocytes in Human Metabolic Diseases

Diseases associated with the disorders of carbohydrate and lipid metabolism are widespread in the modern world. Interaction between the cells of adipose tissue - adipocytes - and immune system cells is an essential factor in pathogenesis of such diseases. Long-term increase in the glucose and fatty acid levels leads to adipocyte hypertrophy and increased expression of pro-inflammatory cytokines and adipokines by these cells. As a result, immune cells acquire a pro-inflammatory phenotype, and new leukocytes are recruited. Inflammation of adipose tissue leads to insulin resistance and stimulates formation of atherosclerotic plaques and development of autoimmunity. New studies show that different groups of B lymphocytes play an essential role in regulation of adipose tissue inflammation. Decrease in the number of B-2 lymphocytes suppresses development of a number of metabolic diseases, whereas decreased numbers of the regulatory B lymphocytes and B-1 lymphocytes are associated with more severe pathology. Recent studies showed that adipocytes influence B lymphocyte activity both directly and by altering activity of other immune cells. These findings provide better understanding of the molecular mechanisms of human pathologies associated with impaired carbohydrate and lipid metabolism, such as type 2 diabetes mellitus.

Genetic Associations of Visfatin Polymorphisms with EGFR Status and Clinicopathologic Characteristics in Lung Adenocarcinoma

Lung adenocarcinoma (LUAD) is the most common histologic type of lung cancer. Mutations of the epidermal growth factor receptor (EGFR) gene are among the most common genetic alterations in LUAD and are the targets of EGFR tyrosine kinase inhibitors. The enzyme visfatin is involved in the generation of the oxidized form of nicotinamide adenine dinucleotide (NAD⁺) and regulation of intracellular adenosine triphosphate (ATP), critical processes in cancer cell survival and growth. This study explored the relationship between visfatin single nucleotide polymorphisms (SNPs) with EGFR status and the clinicopathologic development of LUAD in a cohort of 277 Taiwanese men and women with LUAD. Allelic discrimination of four visfatin SNPs rs11977021, rs61330082, rs2110385 and rs4730153 was determined using a TaqMan Allelic Discrimination assay. We observed higher prevalence rates of advanced (T3/T4) tumors and distant metastases in EGFR wild-type patients carrying the rs11977021 CT + TT and rs61330082 GA + AA genotypes, respectively, compared with patients carrying the CC and GG genotypes. EGFR wild-type patients carrying the rs11977021 CT + TT genotypes were also more likely to develop severe (stage III/IV) malignancy compared with patients carrying the CC genotype. An analysis that included all patients found that the association persisted between the rs11977021 CT + TT and rs61330082 GA + AA genotypes and the development of T3/T4 tumors compared with patients carrying the rs11977021 CC and rs61330082 GG genotypes. In conclusion, these data indicate that visfatin SNPs may help to predict tumor staging in LUAD, especially in patients with EGFR wild-type status.

Role of visfatin in obesity-induced insulin resistance

The growing worldwide burden of insulin resistance (IR) emphasizes the importance of early identification for improved management. Obesity, particularly visceral obesity, has been a key contributing factor in the development of IR. The obesity-associated chronic inflammatory state contributes to the development of obesity-related comorbidities, including IR. Adipocytokines, which are released by adipose tissue, have been investigated as possible indicators of IR. Visfatin was one of the adipocytokines that attracted attention due to its insulin-mimetic activity. It is released from a variety of sources, including visceral fat and macrophages, and it influences glucose metabolism and increases inflammation. The relationship between visfatin and IR in obesity is debatable. As a result, the purpose of this review was to better understand the role of visfatin in glucose homeostasis and to review the literature on the association between visfatin levels and IR, cardiovascular diseases, and renal diseases in obesity.

Nicotinamide Adenine Dinucleotide (NAD) Metabolism as a Relevant Target in Cancer

NAD+ is an important metabolite in cell homeostasis that acts as an essential cofactor in oxidation–reduction (redox) reactions in various energy production processes, such as the Krebs cycle, fatty acid oxidation, glycolysis and serine biosynthesis. Furthermore, high NAD+ levels are required since they also participate in many other nonredox molecular processes, such as DNA repair, posttranslational modifications, cell signalling, senescence, inflammatory responses and apoptosis. In these nonredox reactions, NAD+ is an ADP-ribose donor for enzymes such as sirtuins (SIRTs), poly-(ADP-ribose) polymerases (PARPs) and cyclic ADP-ribose (cADPRs). Therefore, to meet both redox and nonredox NAD+ demands, tumour cells must maintain high NAD+ levels, enhancing their synthesis mainly through the salvage pathway. NAMPT, the rate-limiting enzyme of this pathway, has been identified as an oncogene in some cancer types. Thus, NAMPT has been proposed as a suitable target for cancer therapy. NAMPT inhibition causes the depletion of NAD+ content in the cell, leading to the inhibition of ATP synthesis. This effect can cause a decrease in tumour cell proliferation and cell death, mainly by apoptosis. Therefore, in recent years, many specific inhibitors of NAMPT have been developed, and some of them are currently in clinical trials. Here we review the NAD metabolism as a cancer therapy target.

Reduced nicotinamide adenine dinucleotide phosphate in redox balance and diseases: a friend or foe?

The nicotinamide adenine dinucleotide (NAD⁺/NADH) and nicotinamide adenine dinucleotide phosphate (NADP⁺/NADPH) redox couples function as cofactors or/and substrates for numerous enzymes to retain cellular redox balance and energy metabolism. Thus, maintaining cellular NADH and NADPH balance is critical for sustaining cellular homeostasis. The sources of NADPH generation might determine its biological effects. Newly-recognized biosynthetic enzymes and genetically encoded biosensors help us better understand how cells maintain biosynthesis and distribution of compartmentalized NAD(H) and NADP(H) pools. It is essential but challenging to distinguish how cells sustain redox couple pools to perform their integral functions and escape redox stress. However, it is still obscure whether NADPH is detrimental or beneficial as either deficiency or excess in cellular NADPH levels disturbs cellular redox state and metabolic homeostasis leading to redox stress, energy stress, and eventually, to the disease state. Additional study of the pathways and regulatory mechanisms of NADPH generation in different compartments, and the means by which NADPH plays a role in various diseases, will provide innovative insights into its roles in human health and may find a value of NADPH for the treatment of certain diseases including aging, Alzheimer's disease, Parkinson's disease, cardiovascular diseases, ischemic stroke, diabetes, obesity, cancer, etc.

Mechanism research and treatment progress of NAD pathway related molecules in tumor immune microenvironment

Nicotinamide adenine dinucleotide (NAD) is the core of cellular energy metabolism. NAMPT, Sirtuins, PARP, CD38, and other molecules in this classic metabolic pathway affect many key cellular functions and are closely related to the occurrence and development of many diseases. In recent years, several studies have found that these molecules can regulate cell energy metabolism, promote the release of related cytokines, induce the expression of neoantigens, change the tumor immune microenvironment (TIME), and then play an anticancer role. Drugs targeting these molecules are under development or approved for clinical use. Although there are some side effects and drug resistance, the discovery of novel drugs, the development of combination therapies, and the application of new technologies provide solutions to these challenges and improve efficacy. This review presents the mechanisms of action of NAD  pathway-related molecules in tumor immunity, advances in drug research, combination therapies, and some new technology-related therapies.

From Rate-Limiting Enzyme to Therapeutic Target: The Promise of NAMPT in Neurodegenerative Diseases

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 NAD-dependent 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.

Updated Functional Roles of NAMPT in Carcinogenesis and Therapeutic Niches

Simple Summary

The advantages and applications of using the non-invasive way to detect serum biomarkers for assessing cancer diagnosis and prognosis have been explored. Nicotinamide phosphoribosyltransferase (NAMPT), also designated as pre-B-cell colony-enhancing factor (PBEF) or visfatin, is a secreted adipokine known to modulate tumor malignancies. Its significance in predicting cancer patient’s survival outcome further renders the implementation of NAMPT in clinical practice. In this review, recent discoveries of NAMPT in cancer studies were focused and integrated. We aim to provide updates for researchers who are proposing relevant objectives.

Abstract

Nicotinamide phosphoribosyltransferase (NAMPT) is notable for its regulatory roles in tumor development and progression. Emerging evidence regarding NAMPT somatic mutations in cancer patients, NAMPT expressional signatures in normal tissues and cancers, and the prognostic significance of NAMPT in many cancer types has attracted attention, and NAMPT is considered a potential biomarker of cancer. Recent discoveries have demonstrated the indirect association and direct biological functions of NAMPT in modulating cancer metastasis, proliferation, angiogenesis, cancer stemness, and chemoresistance to anticancer drugs. These findings warrant further investigation of the underlying mechanisms to provide knowledge for developing novel cancer therapeutics. In this review article, we explore recent research developments involving the oncogenic activities of NAMPT by summarizing current knowledge regarding NAMPT somatic mutations, clinical trials, transcriptome data, and clinical information and discoveries related to the NAMPT-induced signaling pathway in modulating hallmarks of cancer. Furthermore, the comprehensive representation of NAMPT RNA expression in a pancancer panel as well as in specific normal cell types at single-cell level are demonstrated. The results suggest potential sites and cell types that could facilitate NAMPT-related tumorigenesis. With this review, we aim to shed light on the regulatory roles of NAMPT in tumor development and progression, and provide information to guide future research directions in this field.

Extracellular nicotinamide phosphoribosyltransferase boosts IFNγ-induced macrophage polarization independently of TLR4

Nicotinamide phosphoribosyltransferase (NAMPT), alongside being a crucial enzyme in NAD synthesis, has been shown to be a secreted protein (eNAMPT), whose levels are increased in patients affected by immune-mediated disorders. Accordingly, preclinical studies have highlighted that eNAMPT participates in the pathogenesis of several inflammatory diseases. Herein, we analyzed the effects of eNAMPT on macrophage-driven inflammation. RNAseq analysis of peritoneal macrophages (PECs) demonstrates that eNAMPT triggers an M1-skewed transcriptional program, and this effect is not dependent on the enzymatic activity. Noteworthy, both in PECs and in human monocyte-derived macrophages, eNAMPT selectively boosts IFNγ-driven transcriptional activation via STAT1/3 phosphorylation. Importantly, the secretion of eNAMPT promotes the chemotactic recruitment of myeloid cells, therefore providing a potential positive feedback loop to foster inflammation. Last, we report that these events are independent of the activation of TLR4, the only eNAMPT receptor that has hitherto been recognized, prompting the knowledge that other receptors are involved.

New Aspects of Corpus Luteum Regulation in Physiological and Pathological Conditions: Involvement of Adipokines and Neuropeptides

The corpus luteum is a small gland of great importance because its proper functioning determines not only the appropriate course of the estrous/menstrual cycle and embryo implantation, but also the subsequent maintenance of pregnancy. Among the well-known regulators of luteal tissue functions, increasing attention is focused on the role of neuropeptides and adipose tissue hormones—adipokines. Growing evidence points to the expression of these factors in the corpus luteum of women and different animal species, and their involvement in corpus luteum formation, endocrine function, angiogenesis, cells proliferation, apoptosis, and finally, regression. In the present review, we summarize the current knowledge about the expression and role of adipokines, such as adiponectin, leptin, apelin, vaspin, visfatin, chemerin, and neuropeptides like ghrelin, orexins, kisspeptin, and phoenixin in the physiological regulation of the corpus luteum function, as well as their potential involvement in pathologies affecting the luteal cells that disrupt the estrous cycle.

circPTPN4 regulates myogenesis via the miR-499-3p/NAMPT axis

Background

Circular RNAs (circRNAs) are a novel class of endogenous ncRNA, which widely exist in the transcriptomes of different species and tissues. Recent studies indicate important roles for circRNAs in the regulation of gene expression by acting as competing endogenous RNAs (ceRNAs). However, the specific role of circRNAs in myogenesis is still poorly understood. In this study, we attempted to systematically identify the circRNAs involved in myogenesis and analyze the biological functions of circRNAs in chicken skeletal muscle development.

Results

In total, 532 circRNAs were identified as being differentially expressed between pectoralis major (PEM) and soleus (SOL) in 7-week-old Xinghua chicken. Among them, a novel circRNA (novel_circ_002621), generated by PTPN4 gene, was named circPTPN4 and identified. circPTPN4 is highly expressed in skeletal muscle, and its expression level is upregulated during myoblast differentiation. circPTPN4 facilitates the proliferation and differentiation of myoblast. Moreover, circPTPN4 suppresses mitochondria biogenesis and activates fast-twitch muscle phenotype. Mechanistically, circPTPN4 can function as a ceRNA to regulate NAMPT expression by sponging miR-499-3p, thus participating in AMPK signaling.

Conclusions

circPTPN4 functions as a ceRNA to regulate NAMPT expression by sponging miR-499-3p, thus promoting the proliferation and differentiation of myoblast, as well as activating fast-twitch muscle phenotype.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-021-00664-1.

Obesity: A Chronic Low-Grade Inflammation and Its Markers

As the prevalence of obesity continues to rise, the world is facing a major public health concern. Obesity is a complex disease associated with an increase in several inflammatory markers, leading to chronic low-grade inflammation. Of multifactorial etiology, it is often used as a measurement of morbidity and mortality. There remains much unknown regarding the association between obesity and inflammation. This review seeks to compile scientific literature on obesity and its associated inflammatory markers in chronic disease and further discusses the role of adipose tissue, macrophages, B-cells, T-cells, fatty acids, amino acids, adipokines, and hormones in obesity. Data were obtained using PubMed and Google Scholar. Obesity, inflammation, immune cells, hormones, fatty acids, and others were search words used to acquire relevant articles. Studies suggest brown adipose tissue is negatively associated with body mass index (BMI) and body fat percentage. Researchers also found the adipose tissue of lean individuals predominantly secretes anti-inflammatory markers, while in obese individuals more pro-inflammatory markers are secreted. Many studies found that adipose tissue in obese individuals showed a shift in immune cells from anti-inflammatory M2 macrophages to pro-inflammatory M1 macrophages, which was also correlated with insulin resistance. Obese individuals generally present with higher levels of hormones such as leptin, visfatin, and resistin. With obesity on the rise globally, it is predicted that severe obesity will become most common amongst low-income adults, black individuals, and women by 2030, making the need for intervention urgent. Further investigation into the association between obesity and inflammation is required to understand the mechanism behind this disease.

Visfatin and global histone H3K9me levels in colon cancer

BACKGROUND

Visfatin is considered to be a biomarker in various types of cancers, including colon cancer. Moreover, evidence for epigenetic mechanism must be reported for an association between visfatin level and colon cancer. Therefore, this study was designed to investigate the status of visfatin expression and the global histone three modifications in colon cancerous tissue.

METHODS

Colon cancerous tissue and paired adjacent non-cancerous tissue from 30 patients were used to determine the global histone three modifications using Western blot. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to assess visfatin's expression level in tissues.

RESULTS

The visfatin and the global H3K9me expression levels were significantly higher in colon cancerous tissue than in the paired adjacent non-cancerous tissue.

CONCLUSION

The present study makes a crucial noteworthy contribution to visfatin effect on colon cancer development via H3K9me.

Insight Into Nicotinamide Adenine Dinucleotide Homeostasis as a Targetable Metabolic Pathway in Colorectal Cancer

Tumour cells modify their cellular metabolism with the aim to sustain uncontrolled proliferation. Cancer cells necessitate adequate amounts of NAD and NADPH to support several enzymes that are usually overexpressed and/or overactivated. Nicotinamide adenine dinucleotide (NAD) is an essential cofactor and substrate of several NAD-consuming enzymes, such as PARPs and sirtuins, while NADPH is important in the regulation of the redox status in cells. The present review explores the rationale for targeting the key enzymes that maintain the cellular NAD/NADPH pool in colorectal cancer and the enzymes that consume or use NADP(H).

Relationship between Adipokines and Cardiovascular Ultrasound Parameters in Metabolic-Dysfunction-Associated Fatty Liver Disease

(1) Background: The role of adipokines such as adiponectin and visfatin in metabolic-dysfunction-associated fatty liver disease (MAFLD) and cardiovascular disease remains unclear. Therefore, we aim to assess serum adiponectin and visfatin levels in MAFLD patients and associated cardiovascular parameters. (2) Methods: A cross-sectional study involving 80 participants (40 MAFLD patients, 40 controls), recruited between January and September 2020, was conducted, using both hepatic ultrasonography and SteatoTestTM to evaluate hepatic steatosis. Echocardiographic and Doppler parameters were assessed. Serum adipokines were measured using ELISA kits. (3) Results: Adiponectin and visfatin levels were not significantly different in MAFLD vs. controls. Visfatin was associated with mean carotid intima-media thickness (p-value = 0.047), while adiponectin was associated with left ventricular ejection fraction (LVEF) (p-value = 0.039) and E/A ratio (p-value = 0.002) in controls. The association between adiponectin and E/A ratio was significant in the univariate analysis at 95% CI (0.0049–0.1331, p-value = 0.035), but lost significance after the multivariate analysis. Although LVEF was not associated with adiponectin in the univariate analysis, significant values were observed after the multivariate analysis (95% CI (−1.83–−0.22, p-value = 0.015)). (4) Conclusions: No significant difference in serum adiponectin and visfatin levels in MAFLD patients vs. controls was found. Interestingly, although adiponectin levels were not associated with LVEF in the univariate analysis, a significant inversely proportional association was observed after the multivariate analysis.

The Association Between Three Adipocytokines (Adiponectin, Resistin and Visfatin) And Thyroid Status in Patients With Type 2 Diabetes Mellitus and Autoimmune Thyroiditis

Autoimmune thyroiditis (AIT) and type 2 diabetes mellitus (DM2) are the most common endocrinological diseases worldwide. Relation between these diseases explains several hypotheses. One of them is influence of some adipocytokines. This study evaluated association between three adipocytokines (adiponectin, resistin and visfatin) and thyroid and glycid status in patients with DM2 and AIT compared to the control group (CG). The group consisted of four subgroups: patients with DM2 without thyreopathies, patients with AIT on substitution therapy without diabetes and prediabetes, patients with DM2 and AIT on substitution therapy and healthy subjects as the CG. We investigated parameters of thyroid and glucose metabolism and serum levels of three adipocytokines. The mean level of resistin in the group of patients with diabetes and thyroiditis was significantly higher than in patients with thyroiditis without diabetes and than in the CG. We found a weak negative correlation between visfatin and fasting glucose levels in patients with thyroiditis without diabetes. We detected a weak negative correlation between resistin and glycated haemoglobin and a weak negative correlation between visfatin and thyroid gland volume in patients with diabetes without thyroiditis. In the CG we determined a weak positive correlation between visfatin and free thyroxin. Our results are consistent with several studies, which confirmed association between AIT and adipocytokines.

Visfatin as a Promising Marker of Cardiometabolic Risk

Adipose tissue is an endocrine organ that produces molecules with important functions in the human body called adipokines. Visfatin can be secreted from various sources, such as macrophages, chondrocytes and amniotic epithelial cells other than adipose tissue. The main effect of visfatin is to promote inflammatory processes. In addition, visfatin has pivotal effects on the entire cardiovascular system, such as endothelial dysfunction, atherosclerosis, plaque rupture and mobilization, myocardial damage, fibrosis and new vessel formation. Vascular pathologies in other tissues also mediate its effects. Visfatin changes in a similar manner to cardiac markers in acute myocardial infarction, and the most cited feature in research studies is that it may be a cardiovascular risk marker. Visfatin is therefore expected to be widely used in cardiovascular pathology in the near future. Visfatin has many target tissues and various effects that occur in relatively complex biological pathways, making it difficult to understand visfatin adequately. In this review, we provide comprehensive information about this promising molecule.

The Extracellular NADome Modulates Immune Responses

The term NADome refers to the intricate network of intracellular and extracellular enzymes that regulate the synthesis or degradation of nicotinamide adenine dinucleotide (NAD) and to the receptors that engage it. Traditionally, NAD was linked to intracellular energy production through shuffling electrons between oxidized and reduced forms. However, recent data indicate that NAD, along with its biosynthetic and degrading enzymes, has a life outside of cells, possibly linked to immuno-modulating non-enzymatic activities. Extracellular NAD can engage puriginergic receptors triggering an inflammatory response, similar - to a certain extent - to what described for adenosine triphosphate (ATP). Likewise, NAD biosynthetic and degrading enzymes have been amply reported in the extracellular space, where they possess both enzymatic and non-enzymatic functions. Modulation of these enzymes has been described in several acute and chronic conditions, including obesity, cancer, inflammatory bowel diseases and sepsis. In this review, the role of the extracellular NADome will be discussed, focusing on its proposed role in immunomodulation, together with the different strategies for its targeting and their potential therapeutic impact.

Dual Roles of Nicotinamide Phosphoribosyltransferase as a Promising Target for Cancer Radiotherapy

Nicotinamide phosphoribosyltransferase (NAMPT) is the key rate-limiting enzyme in the regulation of nicotinamide adenine dinucleotide (NAD) biosynthesis, and its activity is critical for the replenishment of NAD level as well as cell survival or death. As one of the most important components in the electron transport chain of complex I in mitochondrion, sustained supply of NAD is essential to the maintenance of energy metabolism both in normal and cancer cells. Recent research shown that X-ray radiation sharply downregulated the expression of NAMPT, which may be the main cause of radiation damage in salivary gland. Consistently, upregulation of NAMPT by phenylephrine restored the function and tissue structure of salivary gland, indicating the cytoprotective role of NAMPT in preventing radiation damage in normal tissues of patients with head and neck cancer during radiotherapy. On the other hand, NAMPT downregulation and NAD depletion could induce cell death in oral squamous cell cancer, suggesting that a combination of NAMPT inhibitor and radiotherapy presents a promising therapeutic strategy for cancer treatment. Based on our and other's studies, NAMPT may have dual roles in cancer radiotherapy: the upregulation of NAMPT could serve to suppress radiotherapy complications such as radiation sialadenitis, and combination regimens that involve NAMPT inhibitors may enhance efficacy of radiotherapy for cancer treatment.

Serum Visfatin Levels in Nonalcoholic Fatty Liver Disease and Liver Fibrosis: Systematic Review and Meta-Analysis

(1) Background: Recently, adipokines, including visfatin, have been studied in nonalcoholic fatty liver disease (NAFLD). Several studies evaluated visfatin levels in NAFLD, the presence and severity of hepatic steatosis, liver fibrosis, lobar inflammation, nonalcoholic steatohepatitis (NASH), and gender differences. However, inconclusive results have been reported. Accordingly, we performed a systematic review and meta-analysis, aiming to address these gaps in evidence. (2) Methods: We performed a systematic electronic search on PubMed, EMBASE, and Cochrane Library using predefined keywords. Diagnosis of NAFLD by liver biopsy or imagistic investigations was accepted. Full articles satisfying our inclusion and exclusion criteria were included. NHLBI quality assessment tools were used to evaluate included studies. The principal summary outcome was the mean difference in visfatin levels. (3) Results: There were 21 studies involving 1923 individuals included in our qualitative assessment, while 14 studies were included in the quantitative assessment. No statistical significance was found assessing visfatin levels in NAFLD [3.361 (95% CI -0.175-6.897)], simple steatosis [7.523 (95% CI -16.221-31.267)], hepatic steatosis severity [-0.279 (95% CI -1.843-1.285)], liver fibrosis [4.133 (95% CI -3.176-11.443)], lobar inflammation [0.358 (95% CI -1.470-2.185)], NASH [-2.038 (95% CI -6.839-2.763)], and gender [(95% CI -0.554-0.556)]. (4) Conclusions: In conclusion, visfatin levels are not associated with NAFLD, presence or severity of hepatic steatosis, liver fibrosis, lobar inflammation, NASH, and gender. However, due to the limited methodological quality of the included studies, results should be interpreted with caution.

Enhanced NAMPT-Mediated NAD Salvage Pathway Contributes to Psoriasis Pathogenesis by Amplifying Epithelial Auto-Inflammatory Circuits

Dysregulated cross-talk between immune cells and epithelial compartments is responsible for the onset and amplification of pathogenic auto-inflammatory circuits occurring in psoriasis. NAMPT-mediated NAD salvage pathway has been recently described as an immunometabolic route having inflammatory function in several disorders, including arthritis and inflammatory bowel diseases. To date, the role of NAD salvage pathway has not been explored in the skin of patients affected by psoriasis. Here, we show that NAD content is enhanced in lesional skin of psoriatic patients and is associated to high NAMPT transcriptional levels. The latter are drastically reduced in psoriatic skin following treatment with the anti-IL-17A biologics secukinumab. We provide evidence that NAMPT-mediated NAD⁺ metabolism fuels the immune responses executed by resident skin cells in psoriatic skin. In particular, intracellular NAMPT, strongly induced by Th1/Th17-cytokines, acts on keratinocytes by inducing hyper-proliferation and impairing their terminal differentiation. Furthermore, NAMPT-mediated NAD⁺ boosting synergizes with psoriasis-related cytokines in the upregulation of inflammatory chemokines important for neutrophil and Th1/Th17 cell recruitment. In addition, extracellular NAMPT, abundantly released by keratinocytes and dermal fibroblasts, acts in a paracrine manner on endothelial cells by inducing their proliferation and migration, as well as the expression of ICAM-1 membrane molecule and chemokines important for leukocyte recruitment into inflamed skin. In conclusion, our results showed that NAMPT-mediated NAD salvage pathway contributes to psoriasis pathogenic processes by amplifying epithelial auto-inflammatory responses in psoriasis.

Advances in NAD-Lowering Agents for Cancer Treatment

Nicotinamide adenine dinucleotide (NAD) is an essential redox cofactor, but it also acts as a substrate for NAD-consuming enzymes, regulating cellular events such as DNA repair and gene expression. Since such processes are fundamental to support cancer cell survival and proliferation, sustained NAD production is a hallmark of many types of neoplasms. Depleting intratumor NAD levels, mainly through interference with the NAD-biosynthetic machinery, has emerged as a promising anti-cancer strategy. NAD can be generated from tryptophan or nicotinic acid. In addition, the "salvage pathway" of NAD production, which uses nicotinamide, a byproduct of NAD degradation, as a substrate, is also widely active in mammalian cells and appears to be highly exploited by a subset of human cancers. In fact, research has mainly focused on inhibiting the key enzyme of the latter NAD production route, nicotinamide phosphoribosyltransferase (NAMPT), leading to the identification of numerous inhibitors, including FK866 and CHS-828. Unfortunately, the clinical activity of these agents proved limited, suggesting that the approaches for targeting NAD production in tumors need to be refined. In this contribution, we highlight the recent advancements in this field, including an overview of the NAD-lowering compounds that have been reported so far and the related in vitro and in vivo studies. We also describe the key NAD-producing pathways and their regulation in cancer cells. Finally, we summarize the approaches that have been explored to optimize the therapeutic response to NAMPT inhibitors in cancer.

A Stat1 bound enhancer promotes Nampt expression and function within tumor associated macrophages

Tumor associated macrophage responses are regulated by distinct metabolic states that affect their function. However, the ability of specific signals in the local tumor microenvironment to program macrophage metabolism remains under investigation. Here, we identify NAMPT, the rate limiting enzyme in NAD salvage synthesis, as a target of STAT1 during cellular activation by interferon gamma, an important driver of macrophage polarization and antitumor responses. We demonstrate that STAT1 occupies a conserved element within the first intron of Nampt, termed Nampt-Regulatory Element-1 (NRE1). Through disruption of NRE1 or pharmacological inhibition, a subset of M1 genes is sensitive to NAMPT activity through its impact on glycolytic processes. scRNAseq is used to profile in vivo responses by NRE1-deficient, tumor-associated leukocytes in melanoma tumors through the creation of a unique mouse strain. Reduced Nampt and inflammatory gene expression are present in specific myeloid and APC populations; moreover, targeted ablation of NRE1 in macrophage lineages results in greater tumor burden. Finally, elevated NAMPT expression correlates with IFNγ responses and melanoma patient survival. This study identifies IFN and STAT1-inducible Nampt as an important factor that shapes the metabolic program and function of tumor associated macrophages.

The complex role of adipokines in obesity, inflammation, and autoimmunity

The global obesity epidemic is a major contributor to chronic disease and disability in the world today. Since the discovery of leptin in 1994, a multitude of studies have characterized the pathological changes that occur within adipose tissue in the obese state. One significant change is the dysregulation of adipokine production. Adipokines are an indispensable link between metabolism and optimal immune system function; however, their dysregulation in obesity contributes to chronic low-grade inflammation and disease pathology. Herein, I will highlight current knowledge on adipokine structure and physiological function, and focus on the known roles of these factors in the modulation of the immune response. I will also discuss adipokines in rheumatic and autoimmune diseases.

Lipopolysaccharide-Induced Microglial Neuroinflammation: Attenuation by FK866

Alleviating microglia-mediated neuroinflammation bears great promise to reduce neurodegeneration. Nicotinamide phosphoribosyltransferase (NAMPT) may exert cytokine-like effect in the brain. However, it remains unclear about role of NAMPT in microglial inflammation. Also, it remains unknown about effect of NAMPT inhibition on microglial inflammation. In the present study, we observed that FK866 (a specific noncompetitive NAMPT inhibitor) dose-dependently inhibited lipopolysaccharide (LPS)-induced proinflammatory mediator (interleukin (IL)-6, IL-1β, inducible nitric oxide synthase, nitric oxide and reactive species) level increase in BV2 microglia cultures. FK866 also significantly inhibited LPS-induced polarization change in microglia. Furthermore, LPS significantly increased NAMPT expression and nuclear factor kappa B (NF-κB) phosphorylation in microglia. FK866 significantly decreased NAMPT expression and NF-κB phosphorylation in LPS-treated microglia. Finally, conditioned medium from microglia cultures co-treated with FK866 and LPS significantly increased SH-SY5Y and PC12 cell viability compared with conditioned medium from microglia cultures treated with LPS alone. Our study strongly indicates that NAMPT may be a promising target for microglia modulation and NAMPT inhibition may attenuate microglial inflammation.

Association of Adipose Tissue and Adipokines with Development of Obesity-Induced Liver Cancer

Obesity is rapidly dispersing all around the world and is closely associated with a high risk of metabolic diseases such as insulin resistance, dyslipidemia, and nonalcoholic fatty liver disease (NAFLD), leading to carcinogenesis, especially hepatocellular carcinoma (HCC). It results from an imbalance between food intake and energy expenditure, leading to an excessive accumulation of adipose tissue (AT). Adipocytes play a substantial role in the tumor microenvironment through the secretion of several adipokines, affecting cancer progression, metastasis, and chemoresistance via diverse signaling pathways. AT is considered an endocrine organ owing to its ability to secrete adipokines, such as leptin, adiponectin, resistin, and a plethora of inflammatory cytokines, which modulate insulin sensitivity and trigger chronic low-grade inflammation in different organs. Even though the precise mechanisms are still unfolding, it is now established that the dysregulated secretion of adipokines by AT contributes to the development of obesity-related metabolic disorders. This review focuses on several obesity-associated adipokines and their impact on obesity-related metabolic diseases, subsequent metabolic complications, and progression to HCC, as well as their role as potential therapeutic targets. The field is rapidly developing, and further research is still required to fully understand the underlying mechanisms for the metabolic actions of adipokines and their role in obesity-associated HCC.

Another Weapon against Cancer and Metastasis: Physical-Activity-Dependent Effects on Adiposity and Adipokines

Physically active behavior has been associated with a reduced risk of developing certain types of cancer and improved psychological conditions for patients by reducing anxiety and depression, in turn improving the quality of life of cancer patients. On the other hand, the correlations between inactivity, sedentary behavior, and overweight and obesity with the risk of development and progression of various cancers are well studied, mainly in middle-aged and elderly subjects. In this article, we have revised the evidence on the effects of physical activity on the expression and release of the adipose-tissue-derived mediators of low-grade chronic inflammation, i.e., adipokines, as well as the adipokine-mediated impacts of physical activity on tumor development, growth, and metastasis. Importantly, exercise training may be effective in mitigating the side effects related to anti-cancer treatment, thereby underlining the importance of encouraging cancer patients to engage in moderate-intensity activities. However, the strong need to customize and adapt exercises to a patient’s abilities is apparent. Besides the preventive effects of physically active behavior against the adipokine-stimulated cancer risk, it remains poorly understood how physical activity, through its actions as an adipokine, can actually influence the onset and development of metastases.

Inhibition of Pre-B Cell Colony Enhancing Factor Reduces Lung Injury in Rats Receiving Cardiopulmonary Bypass

Objective

Pre-B cell colony enhancing factor (PBEF) is an important proinflammatory cytokine involved in acute lung injury. However, whether PBEF participates in lung injury caused by cardiopulmonary bypass (CPB) is still unknown. This study aimed to investigate the effects of silencing PBEF on lung injury and the sodium and water transport system in rats receiving CPB.

Methods

Morphological changes in lung tissues were evaluated using hematoxylin and eosin (H&E) staining. PBEF was detected using immunohistochemistry. The sodium and water transport system-related proteins and cellular signaling pathways were detected by Western blotting.

Results

Rats receiving CPB (model group) had more severe alveolar wall damage and higher expression of PBEF in free form than the control rats. Western blotting showed that the expression of PBEF, surfactant protein D (SP), aquaporin (AQP) 1, AQP5, and epithelial sodium channel (ENaC) was significantly higher in the lung tissue of CPB rats than control rats. By contrast, adenovirus-encoding sh-PBEF significantly reduced the expression of PBEF, SP, AQP1, AQP5, and ENaC in the lung tissues of rats treated with CPB. The phosphorylation levels of extracellular signal-regulated protein kinases 1 and 2 (ERK1/2), protein kinase B (AKT), and p38 mitogen-activated protein kinase (MAPK) were significantly increased in the lung tissue of rats that received CPB, and were downregulated by adenovirus-encoding sh-PBEF.

Conclusion

Adenovirus-encoding sh-PBEF could reduce lung injury and repair the sodium–water transport system in rats receiving CPB, likely through reducing MAPK, ERK1/2, and Akt signaling pathways.

Cohesive cancer invasion of the biophysical barrier of smooth muscle

Smooth muscle is found around organs in the digestive, respiratory, and reproductive tracts. Cancers arising in the bladder, prostate, stomach, colon, and other sites progress from low-risk disease to high-risk, lethal metastatic disease characterized by tumor invasion into, within, and through the biophysical barrier of smooth muscle. We consider here the unique biophysical properties of smooth muscle and how cohesive clusters of tumor use mechanosensing cell-cell and cell-ECM (extracellular matrix) adhesion receptors to move through a structured muscle and withstand the biophysical forces to reach distant sites. Understanding integrated mechanosensing features within tumor cluster and smooth muscle and potential triggers within adjacent adipose tissue, such as the unique damage-associated molecular pattern protein (DAMP), eNAMPT (extracellular nicotinamide phosphoribosyltransferase), or visfatin, offers an opportunity to prevent the first steps of invasion and metastasis through the structured muscle.

Adipokine role in physiopathology of inflammatory and degenerative musculoskeletal diseases

We performed a systematic literature review to summarize the underlying pathogenic mechanisms by which adipokines influence rheumatological diseases and the resulting clinical manifestations. Increasing evidence display that numerous adipokines may significantly influence the development or clinical course of various rheumatological diseases. Despite the normal anti- or pro-inflammatory role of the cytokines, the serum level varies enormously in various rheumatological diseases. The expression of high levels of pro-inflammatory cytokines such as leptin or visfatin, respectively in systemic lupus erythematosus and in rheumatoid arthritis, represents a negative prognostic factor; other adipokines such as adiponectin, broadly known for their anti-inflammatory effects, showed a correlation with disease activity in rheumatoid arthritis. In the near future pro-inflammatory cytokines may represent a potential therapeutic target to restrain the severity of rheumatological diseases. Further studies on adipokines may provide important information on the pathogenesis of these diseases, which are not yet fully understood. The mechanisms by which adipokines induce, worsen, or suppress inflammatory and degenerative musculoskeletal pathologies and their clinical significance will be discussed in this review.

NAD+ metabolism and its roles in cellular processes during ageing

Nicotinamide adenine dinucleotide (NAD⁺) is a coenzyme for redox reactions, making it central to energy metabolism. NAD⁺ is also an essential cofactor for non-redox NAD⁺-dependent enzymes, including sirtuins, CD38 and poly(ADP-ribose) polymerases. NAD⁺ can directly and indirectly influence many key cellular functions, including metabolic pathways, DNA repair, chromatin remodelling, cellular senescence and immune cell function. These cellular processes and functions are critical for maintaining tissue and metabolic homeostasis and for healthy ageing. Remarkably, ageing is accompanied by a gradual decline in tissue and cellular NAD⁺ levels in multiple model organisms, including rodents and humans. This decline in NAD⁺ levels is linked causally to numerous ageing-associated diseases, including cognitive decline, cancer, metabolic disease, sarcopenia and frailty. Many of these ageing-associated diseases can be slowed down and even reversed by restoring NAD⁺ levels. Therefore, targeting NAD⁺ metabolism has emerged as a potential therapeutic approach to ameliorate ageing-related disease, and extend the human healthspan and lifespan. However, much remains to be learnt about how NAD⁺ influences human health and ageing biology. This includes a deeper understanding of the molecular mechanisms that regulate NAD⁺ levels, how to effectively restore NAD⁺ levels during ageing, whether doing so is safe and whether NAD⁺ repletion will have beneficial effects in ageing humans.

Adipokines in the Skin and in Dermatological Diseases

Adipokines are the primary mediators of adipose tissue-induced and regulated systemic inflammatory diseases; however, recent findings revealed that serum levels of various adipokines correlate also with the onset and the severity of dermatological diseases. Importantly, further data confirmed that the skin serves not only as a target for adipokine signaling, but may serve as a source too. In this review, we aim to provide a complex overview on how adipokines may integrate into the (patho) physiological conditions of the skin by introducing the cell types, such as keratinocytes, fibroblasts, and sebocytes, which are known to produce adipokines as well as the signals that target them. Moreover, we discuss data from in vivo and in vitro murine and human studies as well as genetic data on how adipokines may contribute to various aspects of the homeostasis of the skin, e.g., melanogenesis, hair growth, or wound healing, just as to the pathogenesis of dermatological diseases such as psoriasis, atopic dermatitis, acne, rosacea, and melanoma.

The Adipocyte and Adaptive Immunity

Not only do Adipocytes have energy storage and endocrine functions, but they also play an immunological role. Adipocytes are involved in adaptive immunity to mediate the pathological processes of a variety of chronic inflammatory diseases and autoimmune syndromes. The adaptive immune response consists of T cell-mediated cellular immunity and B cell-mediated humoral immunity. Obese adipocytes overexpress MHC class II molecules and costimulators to act as antigen-presenting cells (APCs) and promote the activation of CD4⁺ T cells. In addition, various adipokines secreted by adipocytes regulate the proliferation and differentiation of T cells. Adipokines are also involved in B cell generation, development, activation, and antibody production. Therefore, adipocytes play an important role in B cell-mediated adaptive immunity. This review describes how adipocytes participate in adaptive immunity from the perspective of T cells and B cells, and discusses their role in the pathogenesis of various diseases.

Visfatin Enhances Breast Cancer Progression through CXCL1 Induction in Tumor-Associated Macrophages

Visfatin, an adipocytokine highly expressed in breast tumor tissues, is associated with breast cancer progression. Recent studies showed that adipocytokines mediate tumor development through adipocytokine tumor-stromal interactions in the tumor microenvironment. This study focused on the interaction between one key stromal constituent-tumor-associated macrophages-and visfatin. Pretreatment of THP-1 and peripheral blood mononuclear cells (PBMCs) with recombinant visfatin resulted in M2-polarization determined by CD163 and CD206 expression. Indirect co-culture with visfatin-treated THP-1 (V-THP-1) promoted the viability, migration, tumorsphere formation, EMT, and stemness of breast cancer cells. Cytokine array identified an increased CXCL1 secretion in V-THP-1 conditioned medium and recombinant CXCL1 enhanced cell migration and invasion, which were abrogated by the CXCL1-neutralizing antibody. Additionally, visfatin induced pERK in THP-1 cells and clinical samples confirmed a positive CXCL1/pERK correlation. In an orthotopic mouse model, the tumor bioluminescent signal of luciferase-expressing MDA-MB-231 (Luc-MDA-MB-231) cells co-cultured with V-THP-1 and the expression of proliferation marker Ki67 were significantly higher than that co-cultured with THP-1. Furthermore, tail vein-injected Luc-MDA-MB-231 pretreated with V-PBMCs conditioned medium metastasized to lungs more frequently compared to control, and this was reversed by CXCL1 blocking antibody. In summary, this study demonstrated that visfatin enhanced breast cancer progression via pERK/CXCL1 induction in macrophages.

Role of Obesity in the Tumorigenesis of Gastric Cancer

Gastric cancer as a common cancer is a multi-factorial disease that is dependent on parallel effects of environment and genetics. Endogenous and host factors, including gender and several genetic backgrounds are known risk factors also many environmental factors, including smoking, diet, infection and increasing body weight and body mass index (BMI) are associated with the gastric cancer. Epidemiological data have consistently demonstrated a positive relation between obesity and gastric cancer, whereas mechanistic studies have sought to uncover obesity related carcinogenic pathways. Biological mechanisms and the relationship between obesity and cancer are complex and not well understood. Different effective factors include obesity-related hormones and adipokines, growth factors, modulation of energy balance and calorie restriction, inflammatory processes and multiple signaling pathways that affect cancer cell promotion and progression. In this review, we will discuss the recent advances in the understanding of the association of obesity changes in the gastric cancer.

Nasser S, Younis N, Bhagani H, Al-Dhaheri Y, Pintus G, Eid AA, El-Yazbi AF, Eid AH. Visfatin: A Possible Role in Cardiovasculo-Metabolic Disorders

Visfatin/NAMPT (nicotinamide phosphoribosyltransferase) is an adipocytokine with several intriguing properties. It was first identified as pre-B-cell colony-enhancing factor but turned out to possess enzymatic functions in nicotinamide adenine dinucleotide biosynthesis, with ubiquitous expression in skeletal muscles, liver, cardiomyocytes, and brain cells. Visfatin exists in an intracellular (iNAMPT) and extracellular (eNAMPT) form. Intracellularly, visfatin/iNAMPT plays a regulatory role in NAD⁺ biosynthesis and thereby affects many NAD-dependent proteins such as sirtuins, PARPs, MARTs and CD38/157. Extracellularly, visfatin is associated with many hormone-like signaling pathways and activates some intracellular signaling cascades. Importantly, eNAMPT has been associated with several metabolic disorders including obesity and type 1 and 2 diabetes. In this review, a brief overview about visfatin is presented with special emphasis on its relevance to metabolic diseases. Visfatin/NAMPT appears to be a unique molecule with clinical significance with a prospective promising diagnostic, prognostic, and therapeutic applications in many cardiovasculo-metabolic disorders.

NEMPD: a network embedding-based method for predicting miRNA-disease associations by preserving behavior and attribute information

Background

As an important non-coding RNA, microRNA (miRNA) plays a significant role in a series of life processes and is closely associated with a variety of Human diseases. Hence, identification of potential miRNA-disease associations can make great contributions to the research and treatment of Human diseases. However, to our knowledge, many existing computational methods only utilize the single type of known association information between miRNAs and diseases to predict their potential associations, without focusing on their interactions or associations with other types of molecules.

Results

In this paper, we propose a network embedding-based method for predicting miRNA-disease associations by preserving behavior and attribute information. Firstly, a heterogeneous network is constructed by integrating known associations among miRNA, protein and disease, and the network representation method Learning Graph Representations with Global Structural Information (GraRep) is implemented to learn the behavior information of miRNAs and diseases in the network. Then, the behavior information of miRNAs and diseases is combined with the attribute information of them to represent miRNA-disease association pairs. Finally, the prediction model is established based on the Random Forest algorithm. Under the five-fold cross validation, the proposed NEMPD model obtained average 85.41% prediction accuracy with 80.96% sensitivity at the AUC of 91.58%. Furthermore, the performance of NEMPD is also validated by the case studies. Among the top 50 predicted disease-related miRNAs, 48 (breast neoplasms), 47 (colon neoplasms), 47 (lung neoplasms) were confirmed by two other databases.

Conclusions

The proposed NEMPD model has a good performance in predicting the potential associations between miRNAs and diseases, and has great potency in the field of miRNA-disease association prediction in the future.

An Update on the Emerging Role of Visfatin in the Pathogenesis of Osteoarthritis and Pharmacological Intervention

Osteoarthritis (OA) is one of the most common degenerative joint diseases that affects millions of people worldwide, mainly the aging population. Despite numerous published reports, little is known about the pathology of this disease, and no feasible treatment plan exists to stop OA progression. Recently, extensive basic and clinical studies have shown that adipokines play a key role in OA development. Moreover, some drugs associated with adipokines have shown chondroprotective and anti-inflammatory effects on OA. Visfatin has been shown to play a detrimental role in the progression of OA. It increases the production of matrix metalloproteinases and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS), induces the production of interleukin (IL)-1β, IL-6, and tumor necrosis factor-α, affects the differentiation of mesenchymal stem cells to adipocytes, and induces osteophyte formation by inhibiting osteoclastogenesis. Although some side effects of chemical visfatin inhibitors have been reported, they were shown to be successful in the treatment of diabetes, cancer, and other diseases that can utilize Chinese herbs, further suggesting that similar therapeutic strategies could be used in OA prevention and treatment. Here, we describe the pathophysiological mechanism of visfatin in OA and discuss some potential pharmacological interventions using Chinese herbs.

The mRNA expression of visfatin and lipocalin-2 in peripheral blood mononuclear cells from patients with pulmonary tuberculosis

Background

In this study, we aimed to assess mRNA expressions of visfatin and lipocalin‐2 in peripheral blood mononuclear cells (PBMCs) from patients with pulmonary tuberculosis (PTB).

Methods

Overall, 79 PTB patients and 71 healthy controls were enrolled. In PBMCs, mRNA expressions of visfatin and lipocalin‐2 were detected using real‐time quantitative polymerase chain reaction (qRT‐PCR), and the diagnostic value of these adipokine mRNAs in PTB patients was calculated through receiver operating characteristic (ROC) analysis.

Results

In PBMCs from PTB patients, the visfatin mRNA level was significantly higher than in healthy controls (P < .001), with no significant association between the lipocalin‐2 mRNA level and PTB patients (P = .933). In PTB patients, lipocalin‐2 mRNA expression positively correlated with the erythrocyte sedimentation rate (ESR) (P = .010). However, the visfatin mRNA level was not associated with any major clinical and laboratory parameter in PTB patients. The ROC curve demonstrated that visfatin could help distinguish PTB patients from healthy controls, with an optimal cutoff value of 0.645 and a corresponding sensitivity of 79.7%.

Conclusions

The altered visfatin mRNA expression indicated that this adipokine might play a role in PTB and could be an auxiliary biomarker for PTB diagnosis.

Nicotinamide Phosphoribosyltransferase Knockdown Leads to Lipid Accumulation in HepG2 Cells through The SIRT1-AMPK Pathway

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.

The Adipokines in Cancer Cachexia

Cachexia is a devastating pathology induced by several kinds of diseases, including cancer. The hallmark of cancer cachexia is an extended weight loss mainly due to skeletal muscle wasting and fat storage depletion from adipose tissue. The latter exerts key functions for the health of the whole organism, also through the secretion of several adipokines. These hormones induce a plethora of effects in target tissues, ranging from metabolic to differentiating ones. Conversely, the decrease of the circulating level of several adipokines positively correlates with insulin resistance, metabolic syndrome, diabetes, and cardiovascular disease. A lot of findings suggest that cancer cachexia is associated with changed secretion of adipokines by adipose tissue. In agreement, cachectic patients show often altered circulating levels of adipokines. This review reported the findings of adipokines (leptin, adiponectin, resistin, apelin, and visfatin) in cancer cachexia, highlighting that to study in-depth the involvement of these hormones in this pathology could lead to the development of new therapeutic strategies.

NAD metabolism in aging and cancer

IMPACT STATEMENT

NAD is a central metabolite connecting energy balance and organismal growth with genomic integrity and function. It is involved in the development of malignancy and has a regulatory role in the aging process. These processes are mediated by a diverse series of enzymes whose common focus is either NAD's biosynthesis or its utilization as a redox cofactor or enzyme substrate. These enzymes include dehydrogenases, cyclic ADP-ribose hydrolases, mono(ADP-ribosyl)transferases, poly(ADP-ribose) polymerases, and sirtuin deacetylases. This article describes the manifold pathways that comprise NAD metabolism and promotes an increased awareness of how perturbations in these systems may be important in disease prevention and/or progression.

Adipokines Expression and Effects in Oocyte Maturation, Fertilization and Early Embryo Development: Lessons from Mammals and Birds

Some evidence shows that body mass index in humans and extreme weights in animal models, including avian species, are associated with low in vitro fertilization, bad oocyte quality, and embryo development failures. Adipokines are hormones mainly produced and released by white adipose tissue. They play a key role in the regulation of energy metabolism. However, they are also involved in many other physiological processes including reproductive functions. Indeed, leptin and adiponectin, the most studied adipokines, but also novel adipokines including visfatin and chemerin, are expressed within the reproductive tract and modulate female fertility. Much of the literature has focused on the physiological and pathological roles of these adipokines in ovary, placenta, and uterine functions. The purpose of this review is to summarize the current knowledge regarding the involvement of leptin, adiponectin, visfatin, and chemerin in the oocyte maturation, fertilization, and embryo development in both mammals and birds.