Pre-B cell colony enhancing factor (PBEF), a cytokine with multiple physiological functions

The function of nicotinamide phosphoribosyl transferase (NAMPT) and its role in diseases

Nicotinamide phosphoribosyl transferase (NAMPT) is a rate-limiting enzyme in the mammalian nicotinamide adenine dinucleotide (NAD) salvage pathway, and plays a vital role in the regulation of cell metabolic activity, reprogramming, aging and apoptosis. NAMPT synthesizes nicotinamide mononucleotide (NMN) through enzymatic action, which is a key protein involved in host defense mechanism and plays an important role in metabolic homeostasis and cell survival. NAMPT is involved in NAD metabolism and maintains intracellular NAD levels. Sirtuins (SIRTs) are a family of nicotinamide adenine dinucleotide (NAD)-dependent histone deacetylases (HDACs), the members are capable of sensing cellular NAD+ levels. NAMPT-NAD and SIRT constitute a powerful anti-stress defense system. In this paper, the structure, biological function and correlation with diseases of NAMPT are introduced, aiming to provide new ideas for the targeted therapy of related diseases.

Comparative Effects of Gymnema sylvestre and Berberine on Adipokines, Body Composition, and Metabolic Parameters in Obese Patients: A Randomized Study

Gymnema sylvestre (GS) and berberine (BBR) are natural products that have demonstrated therapeutic potential for the management of obesity and its comorbidities, as effective and safe alternatives to synthetic drugs. Although their anti-obesogenic and antidiabetic properties have been widely studied, comparative research on their impact on the gene expression of adipokines, such as resistin (Res), omentin (Ome), visfatin (Vis) and apelin (Ap), has not been reported.

METHODOLOGY

We performed a comparative study in 50 adult Mexican patients with obesity treated with GS or BBR for 3 months. The baseline and final biochemical parameters, body composition, blood pressure, gene expression of Res, Ome, Vis, and Ap, and safety parameters were evaluated.

RESULTS

BBR significantly decreased (p < 0.05) body weight, blood pressure and Vis and Ap gene expression and increased Ome, while GS decreased fasting glucose and Res gene expression (p < 0.05). A comparative analysis of the final measurements revealed a lower gene expression of Ap and Vis (p < 0.05) in patients treated with BBR than in those treated with GS. The most frequent adverse effects in both groups were gastrointestinal symptoms, which attenuated during the first month of treatment.

CONCLUSION

In patients with obesity, BBR has a better effect on body composition, blood pressure, and the gene expression of adipokines related to metabolic risk, while GS has a better effect on fasting glucose and adipokines related to insulin resistance, with minimal side effects.

Crosstalk between obesity and cancer: a role for adipokines

Adipose tissue is a complex organ that is increasingly being recognised as the largest endocrine organ in the body. Adipocytes among multiple cell types of adipose tissue can secrete a variety of adipokines, which are involved in signalling pathways and these can be changed by obesity and cancer. There are proposed mechanisms to link obesity/adiposity to cancer development including adipocytokine dysregulation. Among these adipokines, leptin acts through multiple pathways including the STAT3, MAPK, and PI3K pathways involved in cell growth. Adiponectin has the opposite action from leptin in tumour growth partly because of increased apoptotic responses of p53 and Bax. Visfatin increases cancer cell proliferation through ERK1/2, PI3K/AKT, and p38 which are stimulated by proinflammatory cytokines. Omentin through the PI3K/Akt-Nos pathway is involved in cancer-tumour development. Apelin might be involved through angiogenesis in tumour progressions. PAI-1 via its anti-fibrinolytic activity on cell adhesion and uPA/uPAR activity influence cancer cell growth.

NAMPT‑NAD+ is involved in the senescence‑delaying effects of saffron in aging mice

As the proportion of the elderly population grows rapidly, the senescence-delaying effects of Traditional Chinese Medicine is being investigated. The aim of the present study was to investigate the senescence-delaying effects of saffron in naturally aging mice. The active ingredients in an aqueous saffron extract were determined using high-performance liquid chromatography (HPLC). Mice were divided into saffron (8- and 16-months-old) and control groups (3-, 8-, and 16-months-old), and saffron extract was administered to the former groups for 8 weeks. The open field test and Barnes maze test were used to evaluate the locomotor activity, learning and memory function of the mice. The levels of inflammatory factors in the brain were determined by ELISA. In addition, the activities of acetylcholinesterase (AChE) and superoxide dismutase, and the contents of malondialdehyde and nicotinamide adenine dinucleotide (NAD+) were detected by enzyme immunoassay, and the content of NAMPT was detected by ELISA, western blotting and reverse transcription-quantitative PCR. The cellular distribution of NAMPT and synaptic density were evaluated by immunofluorescence, and the pathological morphologies of the liver, skin, kidneys were observed by hematoxylin and eosin staining. HPLC revealed that the crocin and picrocrocin contents of the saffron extract were 19.56±0.14 and 12.00±0.13%, respectively. Saffron exhibited the potential to improve the learning and memory function in aging mice as it increased synaptic density and decreased AChE activity. Also, saffron ameliorated the pathological changes associated with organ aging, manifested by increasing the number of hepatocytes and the thickness of the skin, and preventing the aging-induced ballooning and bleeding in the kidneys. Furthermore, saffron increased the contents of NAMPT and NAD+ in the brain and decreased the content of NAMPT in the serum. In addition, it changed the cellular distribution of NAMPT in aging mice, manifested as reduced NAMPT expression in microglia and astrocytes, and increased NAMPT expression in neurons. Saffron also decreased the contents of proinflammatory cytokines and oxidative stress factors in aging mice. Altogether, these findings indicate that saffron exerts senescence-delaying effects in naturally aging mice, which may be associated with the NAMPT-NAD+ pathway.

Adipokines in Rheumatoid Arthritis: Emerging Biomarkers and Therapeutic Targets

Rheumatoid arthritis (RA) is a chronic inflammatory disease manifested by joint involvement, extra-articular manifestations, and general symptoms. Adipose tissue, previously perceived as an inert energy storage organ, has been recognised as a significant contributor to RA pathophysiology. Adipokines modulate immune responses, inflammation, and metabolic pathways in RA. Although most adipokines have a pro-inflammatory and aggravating effect on RA, some could counteract this pathological process. The coexistence of RA and sarcopenic obesity (SO) has gained attention due to its impact on disease severity and outcomes. Sarcopenic obesity further contributes to the inflammatory milieu and metabolic disturbances. Recent research has highlighted the intricate crosstalk between adipose tissue and skeletal muscle, suggesting potential interactions between these tissues in RA. This review summarizes the roles of adipokines in RA, particularly in inflammation, immune modulation, and joint destruction. In addition, it explores the emerging role of adipomyokines, specifically irisin and myostatin, in the pathogenesis of RA and their potential as therapeutic targets. We discuss the therapeutic implications of targeting adipokines and adipomyokines in RA management and highlight the challenges and future directions for research in this field.

Extracellular nicotinamide phosphoribosyltransferase (eNAMPT) neutralization counteracts T cell immune evasion in breast cancer

BACKGROUND

Nicotinamide phosphoribosyltransferase (NAMPT) is a key intracellular enzyme that participates in nicotinamide adenine dinucleotide (NAD) homeostasis as well as a released cytokine (eNAMPT) that is elevated in inflammatory conditions and in cancer. In patients with breast cancer, circulating eNAMPT is elevated and its plasma levels correlate with prognosis and staging. In light of this, we investigated the contribution of eNAMPT in triple negative mammary carcinoma progression by investigating the effect of its neutralization via a specific neutralizing monoclonal antibody (C269).

METHODS

We used female BALB/c mice injected with 4T1 clone 5 cells and female C57BL6 injected with EO771 cells, evaluating tumoral size, spleen weight and number of metastases. We injected two times a week the anti-eNAMPT neutralizing antibody and we sacrificed the mice after 28 days. Harvested tumors were analyzed by histopathology, flow cytometry, western blot, immunohistochemistry, immunofluorescence and RNA sequencing to define tumor characteristics (isolating tumor infiltrating lymphocytes and tumoral cells) and to investigate the molecular mechanisms behind the observed phenotype. Moreover, we dissected the functional relationship between T cells and tumoral cells using three-dimensional (3D) co-cultures.

RESULTS

The neutralization of eNAMPT with C269 led to decreased tumor size and reduced number of lung metastases. RNA sequencing and functional assays showed that eNAMPT controlled T-cell response via the programmed death-ligand 1/programmed cell death protein 1 (PD-L1/PD-1) axis and its neutralization led to a restoration of antitumoral immune responses. In particular, eNAMPT neutralization was able to activate CD8+IFNγ+GrzB+ T cells, reducing the immunosuppressive phenotype of T regulatory cells.

CONCLUSIONS

These studies indicate for the first time eNAMPT as a novel immunotherapeutic target for triple negative breast cancer.

Cellular Localization and Distribution of TGF-β1, GDNF and PDGF-BB in the Adult Primate Central Nervous System

The available data on the localization of transforming growth factor beta1 (TGF-β1), glial cell line-derived neurotrophic factor (GDNF), and platelet-derived growth factor-BB (PDGF-BB) in the adult primate and human central nervous system (CNS) are limited and lack comprehensive and systematic information. This study aimed to investigate the cellular localization and distribution of TGF-β1, GDNF, and PDGF-BB in the CNS of adult rhesus macaque (Macaca mulatta). Seven adult rhesus macaques were included in the study. The protein levels of TGF-β1, PDGF-BB, and GDNF in the cerebral cortex, cerebellum, hippocampus, and spinal cord were analyzed by western blotting. The expression and location of TGF-β1, PDGF-BB, and GDNF in the brain and spinal cord was examined by immunohistochemistry and immunofluorescence staining, respectively. The mRNA expression of TGF-β1, PDGF-BB, and GDNF was detected by in situ hybridization. The molecular weight of TGF-β1, PDGF-BB, and GDNF in the homogenate of spinal cord was 25 KDa, 30 KDa, and 34 KDa, respectively. Immunolabeling revealed GDNF was ubiquitously distributed in the cerebral cortex, hippocampal formation, basal nuclei, thalamus, hypothalamus, brainstem, cerebellum, and spinal cord. TGF-β1 was least distributed and found only in the medulla oblongata and spinal cord, and PDGF-BB expression was also limited and present only in the brainstem and spinal cord. Besides, TGF-β1, PDGF-BB, and GDNF were localized in the astrocytes and microglia of spinal cord and hippocampus, and their expression was mainly found in the cytoplasm and primary dendrites. The mRNA of TGF-β1, PDGF-BB, and GDNF was localized to neuronal subpopulations in the spinal cord and cerebellum. These findings suggest that TGF-β1, GDNF and PDGF-BB may be associated with neuronal survival, neural regeneration and functional recovery in the CNS of adult rhesus macaques, providing the potential insights into the development or refinement of therapies based on these factors.

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.

Fluorescent and theranostic probes for imaging nicotinamide phosphoribosyl transferase (NAMPT)

Nicotinamide phosphoribosyl transferase (NAMPT) has been regarded as an attractive target for cancer therapy. However, there is a lack of chemical tools for real-time visualization and detection of NAMPT. Herein, the first fluorescent and theranostic probes were designed for imaging NAMPT, which had dual functions of diagnosis and treatment. The designed probes possessed good affinity and environmental sensitivity to NAMPT with a turn-on mechanism and were successfully applied in fluorescence detecting and imaging of NAMPT at the level of living cells and tissue sections. They also effectively inhibited tumor cell proliferation and arrested cell cycle at the G2 phase. These fluorescent probes enabled detection and visualization of NAMPT, representing effective chemical tools for the pathological diagnosis and treatment of cancer.

The Predictive Role of Extracellular NAPRT for the Detection of Advanced Fibrosis in Biopsy-Proven Non-Alcoholic Fatty Liver Disease

Intrahepatic oxidative stress is a key driver of inflammation and fibrogenesis in non-alcoholic fatty liver disease (NAFLD). We aimed to investigate the role of extracellular Nicotinamide phosphoribosyltransferase (eNAMPT) and extracellular nicotinic acid phosphoribosyltransferase (eNAPRT) for the detection of advanced fibrosis. eNAMPT and eNAPRT were tested in 180 consecutive biopsy-proven NAFLD patients and compared with liver stiffness (LS) and the FIB-4 score. eNAMPT was similarly distributed across fibrosis stages, whereas eNAPRT was increased in patients with advanced fibrosis (p = 0.036) and was associated with advanced fibrosis (OR 1.08, p = 0.016). A multiple stepwise logistic regression model containing significant variables for advanced fibrosis (eNAPRT, type 2 diabetes, age, male sex, ALT) had an area under the curve (AUC) of 0.82 (Se 89.6%, Sp 67.3%, PPV 46.7%, NPV 93.8%) when compared to that of LS (0.79; Se 63.5%, Sp 86.2%, PPV 66.0%, NPV 84.8%) and to that of the FIB-4 score (0.73; Se 80.0%, Sp 56.8%, PPV 44.9%, NPV 86.6%). The use of eNAPRT in clinical practice might allow for the better characterization of NAFLD patients at higher risk of disease progression.

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.

Immunologic response in patients with polytrauma

Purpose

It is now known that traumatic injury initiates a complex and dynamic immune response on the first day. It is believed that in patients with polytrauma, these immune responses contribute to the development of infectious complications. Therefore, understanding the immune response to trauma is critical to improving patient outcomes through the development of new therapies and improved resuscitation strategies. The purpose of this study is to examine the parameters of immunity in patients with severe polytrauma at the stages of surgical treatment (the nearest post-traumatic period and long-term periods) in the absence and presence of purulent-inflammatory complications.

Methods

We retrospectively enrolled 188 patients after severely injured trauma and 210 control group at two Level-1 Trauma Centers. Peripheral blood was collected upon presentation to the hospital and at the following time points: 1, 3, 7, 14, 21, 30, 60 and 90 days, and daily during intensive care unit admission. T-lymphocytes analyses performed using a Beckman Coulter EPICS XL flow cytometer (USA) with monoclonal antibodies (Immunotech, France). Analyses of protein levels of cytokines/chemokines, immunoglobulins, and circulating immune complexes was using ELISA.

Results

Under the influence of trauma, the content of T lymphocytes decreased due to the population of T-helpers. However, the number of B lymphocytes increased. The most pronounced activation of humoral immunity was observed by the 30th day of the post-traumatic period. Concentrations of interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor alpha (TNF-a), interleukin-10 (IL-10) on day 1 after injury were the highest. Later, in the post-traumatic period, a gradual decrease in the initially elevated cytokines was noted.

Conclusions

As we continue to extrapolate new information on immune response factors associated with polytrauma, we will be better equipped to develop new therapeutic strategies to treat this serious clinical and social problem. In addition, individually adjusted immune control is an important interactive concept in polytrauma management.

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.

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.

MiR-186-5p Downregulates NAMPT and Functions as a Potential Therapeutic Target for Sepsis-Induced Coagulation Disorders

Purpose

Present study is aimed to explore the role of miR-186-5p in sepsis-induced coagulation disorders and molecular mechanisms.

Methods

Thirty-four sepsis patients and 34 respiratory infection/pneumonia patients were selected in the present study. Polymicrobial sepsis model was created by cecal ligation and puncture (CLP). The mRNA expression was detected by qRT-PCR. Western blot was utilized to measure protein expression. Thromborel S Reagent was applied to measure the prothrombin time (PT). Platelet count of blood was measured via LH 780. ELISA kits were utilized to evaluate the fibrinogen and PAI-1 concentration.

Results

MiR-186-5p expression was lower and nicotinamide phosphoribosyltransferase (NAMPT) mRNA expression was higher in sepsis patients in contrast to control group. Coagulation time was markedly prolonged and platelet count was markedly decreased in CLP mice. In addition, fibrinogen concentration was obviously lower and PAI-1 concentration was obviously higher in CLP mice. MiR-186-5p mimic obviously decreased coagulation time and PAI-1 concentration, while raised platelet count and fibrinogen concentration. Targetscan predicted miR-186-5p might directly regulates NAMPT, and luciferase reporter assay verified this prediction. In addition, miR-186-5p mimic obviously inhibited the mRNA expression of NAMPT. Knockdown of NAMPT improved coagulation dysfunction in sepsis. Overexpression of NAMPT reversed the improvement effect of miR-186-5p on coagulation dysfunction. MiR-186-5p mimic markedly inhibited NF-κB pathway.

Conclusion

MiR-186-5p inhibited sepsis-induced coagulation disorders via targeting NAMPT and inactivating NF-κB pathway.

Effect of visfatin on KATP channel upregulation in colonic smooth muscle cells in diabetic colon dysmotility

The mechanisms of diabetes-related gastrointestinal dysmotility remains unclear. This study aimed to investigate the effect and mechanisms of proinflammatory adipokine visfatin (VF) in the contractile dysfunction of diabetic rat colonic smooth muscle. Twenty Sprague-Dawley rats were randomly divided into control and type 2 diabetes mellitus groups. VF levels in the serum and colonic muscle tissues were tested, the time of the bead ejection and contractility of colonic smooth muscle strips were measured, and the expression of ATP-sensitive potassium (K_ATP) channels in the colonic muscle tissues was analyzed. In vitro, we tested VF's effects on intracellular reactive oxygen species (ROS) levels, NF-κB's nuclear transcription, K_ATP channel expression, intracellular Ca²⁺ concentrations, and myosin light chain (MLC) phosphorylation in colonic smooth muscle cells (CSMCs). The effects of NAC (ROS inhibitor) and BAY 11-7082 (NF-κB inhibitor) on K_ATP expression were also tested. Diabetic rats showed elevated VF levels in serum and colonic muscle tissues, a delayed distal colon ejection response time, weakened contractility of colonic smooth muscle strips, and increased K_ATP channel expression in colonic muscle tissues. VF significantly inhibited the contractility of colonic smooth muscle strips from normal rats. In cultured CSMCs, VF caused ROS overload, increased NF-κB nuclear transcription activity and increased expression of Kir6.1, eventually reducing intracellular Ca²⁺ levels and MLC phosphorylation. NAC and BAY 11-7082 inhibited the VF-induced Kir6.1 upregulation. In conclusion, VF may cause contractile dysfunction of CSMCs by upregulating the expression of the Kir6.1 subunit of K_ATP channels via the ROS/NF-κB pathway and interfering with Ca²⁺ signaling.

Accelerated cardiovascular risk after viral clearance in hepatitis C patients with the NAMPT-rs61330082 TT genotype: An 8-year prospective cohort study

Involvement of extracellular nicotinamide phosphoribosyltransferase (eNAMPT, i.e., visfatin or pre-B-cell colony-enhancing factor), a cancer metabokine, in chronically hepatitis C virus (HCV)-infected (CHC) patients with sustained virological responses (SVRs) remains elusive. This 8-year prospective cohort study evaluated eNAMPT profiles of 842 consecutive CHC patients, including 519 who had completed an anti-HCV therapy course and pre-therapy and 24-week post-therapy surveys. For 842 patients, pre-therapy associations were HCV RNA, homeostatic model assessment for insulin resistance (HOMA-IR) index, and body mass index with eNAMPT levels, and NAMPT-rs61330082 T allele with total cholesterol levels. NAMPT-rs10953502, NAMPT-rs2058539, and NAMPT-rs61330082 were in a linkage disequilibrium block, which was associated with total cholesterol levels. Compared to pre-therapy levels, at 24 weeks post-therapy, decreased eNAMPT and increased lipid levels were observed in SVR patients (n = 427). Among SVR patients, higher cumulative incidences of cardiovascular events occurred in those with a NAMPT-rs61330082 TT genotype than those with non-TT genotypes (28.2% vs. 8.4%, p < 0.001). NAMPT-rs61330082 TT genotype was independently associated with incident cardiovascular events (95% CI hazard ratio (HR): 1.88-10.37; HR: 4.415); no eNAMPT profiles were associated with incident malignancies. Of CHC patients, hepatic vascular endothelial cells and baseline peripheral leukocytes expressed higher eNAMPT levels than controls, and peripheral eNAMPT-positive leukocyte proportions decreased after SVR. During HCV infection, eNAMPT involvement in glucose metabolism was modulated by HCV RNA linked to lipid metabolism and NAMPT-associated SNPs. Hepatic endothelial cells and peripheral leukocytes potentially secrete eNAMPT. Caution is required for incident cardiovascular events in SVR patients with NAMPT-rs61330082 TT genotype.

Nicotinamide phosphoribosyltransferase as a biomarker for the diagnosis of infectious pleural effusions

Nicotinamide phosphoribosyltransferase (NAMPT) has been reported to be involved in infectious diseases, but it is unknown whether it plays a role in infectious pleural effusions (IPEs). We observed the levels of NAMPT in pleural effusions of different etiologies and investigated the clinical value of NAMPT in the differential diagnosis of infectious pleural effusions. A total of 111 patients with pleural effusion were enrolled in the study, including 25 parapneumonic effusions (PPEs) (17 uncomplicated PPEs, 3 complicated PPEs, and 5 empyemas), 30 tuberculous pleural effusions (TPEs), 36 malignant pleural effusions (MPEs), and 20 transudative effusions. Pleural fluid NAMPT levels were highest in the patients with empyemas [575.4 (457.7, 649.3) ng/ml], followed by those with complicated PPEs [113.5 (103.5, 155.29) ng/ml], uncomplicated PPEs [24.9 (20.2, 46.7) ng/ml] and TPEs [88 (19.4, 182.6) ng/ml], and lower in patients with MPEs [11.5 (6.5, 18.4) ng/ml] and transudative effusions [4.3 (2.6, 5.1) ng/ml]. Pleural fluid NAMPT levels were significantly higher in PPEs (P < 0.001) or TPEs (P < 0.001) than in MPEs. Moreover, Pleural fluid NAMPT levels were positively correlated with the neutrophil percentage and lactate dehydrogenase (LDH) levels and inversely correlated with glucose levels in both PPEs and TPEs, indicating that NAMPT was implicated in the neutrophil-associated inflammatory response in infectious pleural effusion. Further, multivariate logistic regression analysis showed pleural fluid NAMPT was a significant predictor distinguishing PPEs from MPEs [odds ratio (OR) 1.180, 95% confidence interval (CI) 1.052-1.324, P = 0.005]. Receiver-operating characteristic (ROC) analysis demonstrated that NAMPT was a promising diagnostic factor for the diagnosis of infectious effusions, with the areas under the curve for pleural fluid NAMPT distinguishing PPEs from MPEs, TPEs from MPEs, and IPEs (PPEs and TPEs) from NIPEs were 0.92, 0.85, and 0.88, respectively. In conclusion, pleural fluid NAMPT could be used as a biomarker for the diagnosis of infectious pleural effusions.

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.

Alterations in rat adipose tissue transcriptome and proteome in response to prolonged fasting

Various pathophysiological situations of negative energy balance involve the intense depletion of the body's energy reserves. White adipose tissue is a central place to store energy and a major endocrine organ. As a model of choice to better understand how the white adipose tissue dynamically responds to changes in substrate availability, we used the prolonged fasting paradigm, which is characterized by successive periods of stimulated (phase 2) and then reduced (phase 3) lipid mobilization/utilization. Using omics analyses, we report a regulatory transcriptional program in rat epididymal (EPI) adipose tissue favoring lipolysis during phase 2 and repressing it during phase 3. Changes in gene expression levels of lipases, lipid droplet-associated factors, and the proteins involved in cAMP-dependent and cAMP-independent regulation of lipolysis are highlighted. The mRNA and circulating levels of adipose-secreted factors were consistent with the repression of insulin signaling during prolonged fasting. Other molecular responses are discussed, including the regulation of leptin and adiponectin levels, the specific changes reflecting an increased fibrinolysis and a possible protein catabolism-related energy saving mechanism in late fasting. Finally, some differences between internal and subcutaneous (SC) adipose tissues are also reported. These data provide a comprehensive molecular basis of adipose tissue responses when facing a major energetic challenge.

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.

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.

Optimization and bioactivity verification of porcine recombinant visfatin with high expression and low endotoxin content using pig liver as template

In order to obtain the porcine recombinant visfatin protein with high expression and low endotoxin content, the current study aims to express and verify the biological activity of the purified porcine recombinant visfatin protein. Firstly, four different expression strains were successfully constructed. Then they were simultaneously induced at 37 °C for 4 h and 16 °C for 16 h. The results showed that Visfatin-pET28a-Transetta was the best strain with high protein expression and purity at 16 °C induction for 16 h. After that, endotoxin was reduced from the recombinant visfatin until the residual endotoxin was less than one endotoxin units per milliliter (EU/mL). Finally, the purified porcine recombinant visfatin protein was incubated with RAW264.7 cells. The results of cell counting kit-8 (CCK-8) showed the survival rate of the cells first increased and then decreased with the increase in visfatin concentration. When the concentration of visfatin was 700 ng/mL, the survival rate of the cells was the highest. Thereafter, control (PBS), Visfatin and Visfatin + PolymyxinB (Ploy.B) groups were incubated with the RAW264.7 cells for 6 h. Real-time quantitative polymerase chain reaction (RT-qPCR) and Enzyme Linked Immuno-Sorbent Assay (ELISA) results showed that, as compared to the control group, the expressions of interleukin (IL)-1β, tumor necrosis factor (TNF)-α and monocyte chemoattractant protein (MCP)-1 in Visfatin group were significantly increased (P < 0.05). However, there was no significant difference between the Visfatin and Visfatin + Poly.B groups, indicating that porcine recombinant visfatin protein promoted the inflammatory activity of RAW264.7 cells while the residual endotoxin did not play a role, suggesting biological activity of porcine recombinant visfatin protein.

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.

Genes upregulated in the amnion at labour are bivalently marked by activating and repressive histone modifications

Inflammatory genes are expressed increasingly in the foetal membranes at late gestation triggering birth. Here we have examined whether epigenetic histone modifications contribute to the upregulation of proinflammatory genes in the amnion in late pregnancy and at labour. Amnion samples were collected from early pregnancy, at term in the absence of labour and after spontaneous birth. The expression of the labour-associated proinflammatory genes PTGS2, BMP2 and NAMPT was determined by reverse transcription-coupled quantitative real-time PCR (qRT-PCR). Chromatin immunoprecipitation (ChIP) and sequential double ChIP were performed to determine the levels and co-occurrence of activating histone-3, lysine-4 trimethylation (H3K4me3) and repressive histone-3, lysine-27 trimethylation (H3K27me3) at the gene promoters. H3K4 methyltransferase, H3K27me3 demethylase and H3K27 methyltransferase expression was determined by qRT-PCR and immunofluorescence confocal microscopy. PTGS2, BMP2 and NAMPT expression was upregulated robustly between early pregnancy and term (P < 0.05). The promoters were marked bivalently by both the H3K4me3 and H3K27me3 modifications. Bivalence was reduced at term by the decrease of the H3K27me3-modified fraction of promoter copies marked by H3K4me3 indicating epigenetic activation. Messenger RNAs encoding the H3K4-specific methyl transferases MLL1,-2,-3,-4, SETD1A,-B and the H3K27me3-specific demethylases KDM6A,-B were expressed increasingly while the H3K27 methyl transferase EZH2 was expressed decreasingly at term. Histone modifying enzyme proteins were detected in amnion epithelial and mesenchymal cells. These results with prototypical proinflammatory genes suggest that nucleosomes at labour-promoting genes are marked bivalently in the amnion, which is shifted towards monovalent H3K4me3 modification at term when the genes are upregulated. Bivalent epigenetic regulation by histone modifying enzymes may control the timing of labour.

Recent Advances in NAMPT Inhibitors: A Novel Immunotherapic Strategy

Nicotinamide adenine dinucleotide (NAD) is a cofactor of many enzymatic reactions as well as being a substrate for a number of NAD-consuming enzymes (e.g., PARPS, sirtuins, etc). NAD can be synthesized de novo starting from tryptophan, nicotinamide, nicotinic acid, or nicotinamide riboside from the diet. On the other hand, the nicotinamide that is liberated by NAD-consuming enzymes can be salvaged to re-form NAD. In this former instance, nicotinamide phosphoribosyltransferase (NAMPT) is the bottleneck enzyme. In the many cells in which the salvage pathway is predominant, NAMPT, therefore, represents an important controller of intracellular NAD concentrations, and as a consequence of energy metabolism. It is, therefore, not surprising that NAMPT is over expressed by tumoral cells, which take advantage from this to sustain growth rate and tumor progression. This has led to the initiation of numerous medicinal chemistry programs to develop NAMPT inhibitors in the context of oncology. More recently, however, it has been shown that NAMPT inhibitors do not solely target the tumor but also have an effect on the immune system. To add complexity, this enzyme can also be secreted by cells, and in the extracellular space it acts as a cytokine mainly through the activation of Toll like Receptor 4 (TLR4), although it has not been clarified yet if this is the only receptor responsible for its actions. While specific small molecules have been developed only against the intracellular form of NAMPT, growing evidences sustain the possibility to target the extracellular form. In this contribution, the most recent evidences on the medicinal chemistry of NAMPT will be reviewed, together with the key elements that sustain the hypothesis of NAMPT targeting and the drawbacks so far encountered.

NAMPT and NAPRT: Two Metabolic Enzymes With Key Roles in Inflammation

Nicotinamide phosphoribosyltransferase (NAMPT) and nicotinate phosphoribosyltransferase (NAPRT) are two intracellular enzymes that catalyze the first step in the biosynthesis of NAD from nicotinamide and nicotinic acid, respectively. By fine tuning intracellular NAD levels, they are involved in the regulation/reprogramming of cellular metabolism and in the control of the activity of NAD-dependent enzymes, including sirtuins, PARPs, and NADases. However, during evolution they both acquired novel functions as extracellular endogenous mediators of inflammation. It is well-known that cellular stress and/or damage induce release in the extracellular milieu of endogenous molecules, called alarmins or damage-associated molecular patterns (DAMPs), which modulate immune functions through binding pattern recognition receptors (PRRs), such as Toll-like receptors (TLRs), and activate inflammatory responses. Increasing evidence suggests that extracellular (e)NAMPT and eNAPRT are novel soluble factors with cytokine/adipokine/DAMP-like actions. Elevated eNAMPT were reported in several metabolic and inflammatory disorders, including obesity, diabetes, and cancer, while eNAPRT is emerging as a biomarker of sepsis and septic shock. This review will discuss available data concerning the dual role of this unique family of enzymes.

Effects of genistein on lipopolysaccharide-induced injury of mouse alveolar epithelial cells and its mechanism

Alveolar and bronchial epithelial cells have critical functions in acute respiratory distress syndrome progress. Genistein could protect the lungs from acute lung injury, however, whether genistein protects the alveolar epithelial cells from LPS-induced injury was less studied. Spectrophotometric method 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) and enzyme-linked immunosorbent assay (ELISA) were performed to detect cell viability and levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6. Flow cytometry and western blot assay were performed to detect cells apoptosis and protein levels. In LPS-induced model of mouse lung epithelial (MLE)-12 cells, PBEF (proinflammatory cytokine) expression, and cell apoptosis were increased and cell viability was decreased, whereas NF-κB was activated and expression levels of TNF-α, IL-1β, and IL-6 were increased. However, genistein partly reversed the effect of LPS, and it plays a protective role in lung injury by reducing expression of PBEF, inhibiting the activation of NF-κB and alleviating inflammatory response of cells.

MicroRNA Mediate Visfatin and Resistin Induction of Oxidative Stress in Human Osteoarthritic Synovial Fibroblasts Via NF-κB Pathway

Synovial membrane inflammation actively participate to structural damage during osteoarthritis (OA). Adipokines, miRNA, and oxidative stress contribute to synovitis and cartilage destruction in OA. We investigated the relationship between visfatin, resistin and miRNA in oxidative stress regulation, in human OA synovial fibroblasts. Cultured cells were treated with visfatin and resistin. After 24 h, we evaluated various pro-inflammatory cytokines, metalloproteinases (MMPs), type II collagen (Col2a1), miR-34a, miR-146a, miR-181a, antioxidant enzymes, and B-cell lymphoma (BCL)2 by qRT-PCR, apoptosis and mitochondrial superoxide production by cytometry, p50 nuclear factor (NF)-κB by immunofluorescence. Synoviocytes were transfected with miRNA inhibitors and oxidative stress evaluation after adipokines stimulus was performed. The implication of NF-κB pathway was assessed by the use of a NF-κB inhibitor (BAY-11-7082). Visfatin and resistin significantly up-regulated gene expression of interleukin (IL)-1β, IL-6, IL-17, tumor necrosis factor (TNF)-α,MMP-1, MMP-13 and reduced Col2a1. Furthermore, adipokines induced apoptosis and superoxide production, the transcriptional levels of BCL2, superoxide dismutase (SOD)-2, catalase (CAT), nuclear factor erythroid 2 like 2 (NRF2), miR-34a, miR-146a, and miR-181a. MiRNA inhibitors counteracted adipokines modulation of oxidative stress. Visfatin and resistin effects were suppressed by BAY-11-7082. Our data suggest that miRNA may represent possible mediators of oxidative stress induced by visfatin and resistin via NF-κB pathway in human OA synoviocytes.

Pre-B-cell colony enhancing factor regulates the alveolar epithelial sodium-water transport system through the ERK and AKT pathways

The sodium-water transport system is crucial for alveolar fluid clearance. The pulmonary edema caused by extracorporeal circulation is mainly due to increased alveolar capillary permeability and reduced fluid clearance. We previously demonstrated that pre-B-cell colony enhancing factor (PBEF) increases alveolar capillary permeability and inhibits the sodium-water transport system. However, the specific mechanism by which PBEF inhibits the sodium-water transport system is unclear. In this study, we used HPAEpiC (alveolar type II epithelial cells) to construct an anoxia-reoxygenation model and simulate the extracorporeal circulation microenvironment. The impact of PBEF on the expression of genes and proteins implicated in sodium transport and its effect on the activation status of the ERK, P38, and AKT signaling pathways were explored in HPAEpiC by real-time fluorescent PCR and western blotting. Specific inhibitors were employed to verify the role of the three signaling pathways in the regulation of the sodium-water transport system. PBEF was substantially non-toxic to alveolar epithelial cells, inhibited the expression of ENaC, NKA, and AQP1, and affected the ERK, P38, and AKT signaling pathways. ERK pathway inhibitors attenuated PBEF-induced downregulation of EnaC, NKA, and AQP1, and increased NKA activity. P38 pathway inhibitors only attenuated PBEF-induced suppression of NKA expression. AKT pathway inhibitors potentiated the inhibitory effects of PBEF, reducing EnaC, AQP1, and NKA expression, as well as NKA activity. In conclusion, PBEF inhibited the sodium-water transport system by activation of ERK and suppression of AKT signaling.

NAD-Biosynthetic and Consuming Enzymes as Central Players of Metabolic Regulation of Innate and Adaptive Immune Responses in Cancer

Cancer cells, particularly in solid tumors, are surrounded by non-neoplastic elements, including endothelial and stromal cells, as well as cells of immune origin, which can support tumor growth by providing the right conditions. On the other hand, local hypoxia, and lack of nutrients induce tumor cells to reprogram their metabolism in order to survive, proliferate, and disseminate: the same conditions are also responsible for building a tumor-suppressive microenvironment. In addition to tumor cells, it is now well-recognized that metabolic rewiring occurs in all cellular components of the tumor microenvironment, affecting epigenetic regulation of gene expression and influencing differentiation/proliferation decisions of these cells. Nicotinamide adenine dinucleotide (NAD) is an essential co-factor for energy transduction in metabolic processes. It is also a key component of signaling pathways, through the regulation of NAD-consuming enzymes, including sirtuins and PARPs, which can affect DNA plasticity and accessibility. In addition, both NAD-biosynthetic and NAD-consuming enzymes can be present in the extracellular environment, adding a new layer of complexity to the system. In this review we will discuss the role of the “NADome” in the metabolic cross-talk between cancer and infiltrating immune cells, contributing to cancer growth and immune evasion, with an eye to therapeutic implications.

Nicotinamide phosphoribosyltransferase secreted from microglia via exosome during ischemic injury

Nicotinamide phosphoribosyltransferase (NAMPT) is the key enzyme of the salvage pathway of nicotinamide adenine dinucleotide synthesis. NAMPT can also be secreted and functions as a cytokine. We have previously shown that in the brain, NAMPT expression and secretion can be induced in microglia upon neuroinflammation and injury. Yet the mechanism for NAMPT secretion remains unclear. Here we show that NAMPT can be actively secreted from microglia upon the treatment of ischemia-like injury - oxygen-glucose deprivation and recovery (OGD/R). We confirmed that classical ER-Golgi pathway is not involved in NAMPT secretion. NAMPT secretion was further enhanced by ATP, and the secretion was mediated by P2X₇ receptor and by intracellular Ca²⁺ . Importantly, we found that phospholipase D inhibitor, n-butanol, phospholipase D siRNA, and wortmannin significantly decreased OGD/R-induced and ATP-enhanced release of NAMPT in microglia. After excluding the mechanisms of involving secretory autophagy, endosomes, and secretory lysosome, we have concluded that microglial NAMPT is secreted mainly via exosome. Immune-electron microscopy identifies NAMPT in extracellular vesicles with the size and morphology characteristic of exosome. With the vesicles harvested by ultra-centrifugation, exosomal NAMPT is further confirmed by Western blotting analysis. Intriguingly, the amount of NAMPT relative to exosomal protein markers remains unchanged upon the treatment of OGD/R, suggesting a constant load of exosomal NAMPT in microglia. Taken together, we have identified NAMPT is actively secreted via exosome from microglia during neuroinflammation of ischemic injury.

MicroRNA410 Inhibits Pulmonary Vascular Remodeling via Regulation of Nicotinamide Phosphoribosyltransferase

Nicotinamide phosphoribosyltransferase (NAMPT) upregulation in human pulmonary artery endothelial cells (hPAECs) is associated with pulmonary arterial hypertension (PAH) progression and pulmonary vascular remodeling. The underlying mechanisms regulating NAMPT expression are still not clear. In this study, we aimed to study the regulation of NAMPT expression by microRNA410 (miR410) in hPAECs and explore the role of miR410 in the pathogenesis of experimental pulmonary hypertension. We show that miR410 targets the 3' UTR of NAMPT and that, concomitant with NAMPT upregulation, miR410 is downregulated in lungs of mice exposed to hypoxia-induced pulmonary hypertension (HPH). Our results also demonstrate that miR410 directly inhibits NAMPT expression. Overexpression of miR410 in hPAECs inhibits basal and VEGF-induced proliferation, migration and promotes apoptosis of hPAECs, while miR410 inhibition via antagomirs has the opposite effect. Finally, administration of miR410 mimics in vivo attenuated induction of NAMPT in PAECs and prevented the development of HPH in mice. Our results highlight the role of miR410 in the regulation of NAMPT expression in hPAECs and show that miR410 plays a potential role in PAH pathobiology by targeting a modulator of pulmonary vascular remodeling.

Visfatin serum concentration and hepatic mRNA expression in chronic hepatitis C

Aim of the study

Chronic hepatitis C (CHC) is a viral disease with metabolic disturbances involved in its pathogenesis. Adipokines may influence the inflammatory response and contribute to development of metabolic abnormalities in CHC. Visfatin exerts immunomodulatory and insulin-mimetic effects. The aim was to measure visfatin serum concentrations and its mRNA hepatic expression in non-obese CHC patients and to assess the relationships with metabolic and histological parameters.

Material and methods

In a group of 63 non-obese CHC patients (29 M/34 F) infected with genotype 1b aged 46.6 ±14.6 years, body mass index (BMI) 24.8 ±3.0 kg/m², serum visfatin levels and its mRNA hepatic expression were examined and the subsequent associations with metabolic and histopathological features were assessed.

Results

Serum visfatin levels were significantly higher in CHC patients compared to controls (22.7 ±5.7 vs. 17.8 ±1.5 ng/ml, p < 0.001). There was no difference in serum visfatin and its mRNA hepatic expression regardless of sex, BMI, insulin sensitivity and lipids concentrations. There was no mutual correlation between serum visfatin and visfatin mRNA hepatic expression. Hepatic visfatin mRNA levels but not visfatin serum levels were higher in patients with steatosis (1.35 ±0.75 vs. 0.98 ±0.34, p = 0.009).

Conclusions

Serum visfatin levels may reflect its involvement in chronic inflammatory processes accompanying HCV infection. Increased visfatin mRNA hepatic expression in patients with steatosis seems to be a compensatory mechanism enabling hepatocytes to survive metabolic abnormalities resulting from virus-related lipid droplet deposition prerequisite to HCV replication.

Inhibition of GIP signaling extends lifespan without caloric restriction

AIMS/INTRODUCTION

Caloric restriction (CR) promotes longevity and exerts anti-aging effects by increasing Sirtuin production and activation. Gastric inhibitory polypeptide (GIP), a gastrointestinal peptide hormone, exerts various effects on pancreatic β-cells and extra-pancreatic tissues. GIP promotes glucose-dependent augmentation of insulin secretion and uptake of nutrients into the adipose tissue.

MATERIALS AND METHODS

Gipr^-/- and Gipr^+/+ mice were used for lifespan analysis, behavior experiments and gene expression of adipose tissue and muscles. 3T3-L1 differentiated adipocytes were used for Sirt1 and Nampt expression followed by treatment with GIP and α-lipoic acid.

RESULTS

We observed that GIP receptor-knockout (Gipr^-/-) mice fed normal diet showed an extended lifespan, increased exploratory and decreased anxiety-based behaviors, which are characteristic behavioral changes under CR. Moreover, Gipr^-/- mice showed increased Sirt1 and Nampt expression in the adipose tissue. GIP suppressed α-lipoic acid-induced Sirt1 expression and activity in differentiated adipocytes.

CONCLUSIONS

Although maintenance of CR is difficult, food intake and muscle endurance of Gipr^-/- mice were similar to those of wild-type mice. Inhibition of GIP signaling may be a novel strategy to extend the lifespan of diabetic patients.

Essential Role of Visfatin in Lipopolysaccharide and Colon Ascendens Stent Peritonitis-Induced Acute Lung Injury

Acute lung injury (ALI) is a life-threatening syndrome characterized by acute and severe hypoxemic respiratory failure. Visfatin, which is known as an obesity-related cytokine with pro-inflammatory activities, plays a role in regulation of inflammatory cytokines. The mechanisms of ALI remain unclear in critically ill patients. Survival in ALI patients appear to be influenced by the stress generated by mechanical ventilation and by ALI-associated factors that initiate the inflammatory response. The objective for this study was to understand the mechanisms of how visfatin regulates inflammatory cytokines and promotes ALI. The expression of visfatin was evaluated in ALI patients and mouse sepsis models. Moreover, the underlying mechanisms were investigated using human bronchial epithelial cell lines, BEAS-2B and NL-20. An increase of serum visfatin was discovered in ALI patients compared to normal controls. Results from hematoxylin and eosin (H&E) and immunohistochemistry staining also showed that visfatin protein was upregulated in mouse sepsis models. Moreover, lipopolysaccharide (LPS) induced visfatin expression, activated the STAT3/NFκB pathway, and increased the expression of pro-inflammatory cytokines, including IL1-β, IL-6, and TNF-α in human bronchial epithelial cell lines NL-20 and BEAS-2B. Co-treatment of visfatin inhibitor FK866 reversed the activation of the STAT3/NFκB pathway and the increase of pro-inflammatory cytokines induced by LPS. Our study provides new evidence for the involvement of visfatin and down-stream events in acute lung injury. Further studies are required to confirm whether the anti-visfatin approaches can improve ALI patient survival by alleviating the pro-inflammatory process.

Nicotinamide adenine dinucleotide emerges as a therapeutic target in aging and ischemic conditions

Nicotinamide adenine dinucleotide (NAD⁺) has been described as central coenzyme of redox reactions and is a key regulator of stress resistance and longevity. Aging is a multifactorial and irreversible process that is characterized by a gradual diminution in physiological functions in an organism over time, leading to development of age-associated pathologies and eventually increasing the probability of death. Ischemia is the lack of nutritive blood flow that causes damage and mortality that mostly occurs in various organs during aging. During the process of aging and related ischemic conditions, NAD⁺ levels decline and lead to nuclear and mitochondrial dysfunctions, resulting in age-related pathologies. The majority of studies have shown that restoring of NAD⁺ using supplementation with intermediates such as nicotinamide mononucleotide and nicotinamide riboside can be a valuable strategy for recovery of ischemic injury and age-associated defects. This review summarizes the molecular mechanisms responsible for the reduction in NAD⁺ levels during ischemic disorders and aging, as well as a particular focus is given to the recent progress in the understanding of NAD⁺ precursor's effects on aging and ischemia.

Effect of freeze-dried Carica papaya leaf juice on inflammatory cytokines production during dengue virus infection in AG129 mice

Background

Carica papaya leaves have been used for traditional treatment of dengue fever and have been reported to exhibit an immunomodulatory activity by affecting the level of cytokine production in vitro and in vivo. Due to the lack of adequate in vivo evidence in dengue disease model, the present study was initiated to screen and identify the cytokines affected by freeze-dried C. papaya leaf juice (FCPLJ) treatment in AG129 mice infected with DEN-2 dengue virus.

Methods

The AG129 mice were fed orally with FCPLJ for 3 consecutive days after 24 h of dengue virus inoculation. Plasma cytokines were screened by using ProcartaPlex immunoassay. The gene expression in the liver was analyzed by using RT² Profiler PCR Array.

Results

The results showed that FCPLJ treatment has increased the plasma CCL2/MCP-1 level during peak of viremia. Gene expression study has identified 8 inflammatory cytokine genes which were downregulated in the liver of infected AG129 mice treated with FCPLJ. The downregulated inflammatory cytokine genes were CCL6/MRP-1, CCL8/MCP-2, CCL12/MCP-5, CCL17/TARC, IL1R1, IL1RN/IL1Ra, NAMPT/PBEF1 and PF4/CXCL4.

Conclusion

The findings indicated the possible immunomodulatory role of FCPLJ during dengue virus infection in AG129 mice.

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2438-3) contains supplementary material, which is available to authorized users.

A Complex Relationship between Visfatin and Resistin and microRNA: An In Vitro Study on Human Chondrocyte Cultures

Growing evidence indicates the important role of adipokines and microRNA (miRNA) in osteoarthritis (OA) pathogenesis. The purpose of the present study was to investigate the effect of visfatin and resistin on some miRNA (34a, 140, 146a, 155, 181a, let-7e), metalloproteinases (MMPs), and collagen type II alpha 1 chain (Col2a1) in human OA chondrocytes and in the T/C-28a2 cell line. The implication of nuclear factor (NF)-κB in response to adipokines was also assessed. Chondrocytes were stimulated with visfatin (5 or 10 μg/mL) and resistin (50 or 100 ng/mL) with or without NF-κB inhibitor (BAY-11-7082, 1 μM) for 24 h. Viability and apoptosis were detected by MMT and cytometry, miRNA, MMP-1, MMP-13, and Col2a1 by qRT-PCR and NF-κB activation by immunofluorescence. Visfatin and resistin significantly reduced viability, induced apoptosis, increased miR-34a, miR-155, miR-181a, and miR-let7e, and reduced miR-140 and miR-146a gene expression in OA chondrocytes. MMP-1, MMP-13, and Col2a1 were significantly modulated by treatment of OA chondrocytes with adipokines. Visfatin and resistin significantly increased NF-κB activation, while the co-treatment with BAY11-7082 did not change MMPs or Col2a1 levels beyond that caused by single treatment. Visfatin and resistin regulate the expression levels of some miRNA involved in OA pathogenesis and exert catabolic functions in chondrocytes via the NF-κB pathway. These data confirm the complex relationship between adipokines and miRNA.

Clinical Significance of Serum Visfatin in Renal Transplant Recipients

Chronic antibody-mediated rejection is the most common cause of late graft loss in renal transplant recipients. Visfatin is a pre-B cell colony-enhancing factor secreted by activated lymphocytes. We hypothesize that visfatin may play a role in the augmentation of B cell colonies and facilitate antibody-mediated rejection. Renal transplant recipients were randomly selected for the study. Fasting blood samples were obtained for the assay of visfatin. The participants were prospectively followed up for 3 years. A total of 146 patients were recruited for the study and were divided into 3 groups according to tertile of serum visfatin level. At the end of follow-up, 6 patients had graft loss, including 1 graft loss in tertile 1, 3 in tertile 2, and 2 in tertile 3 (P = .60). Fourteen patients experienced at least 1 episode of acute rejection, while 21 patients were diagnosed as having chronic rejection. The distribution of acute rejection was 10.2% in tertile 1, 10.2% in tertile 2, and 8.3% in tertile 3 (P = .94); chronic rejection occurred in 10.2%, 16.3%, and 16.7%, respectively (P = .59). We conclude that serum visfatin level was not correlated with either graft failure or patient mortality in a 3-year observation period.

Extracellular nicotinamide phosphoribosyltransferase (eNAMPT) is a novel marker for patients with BRAF-mutated metastatic melanoma

Metastatic melanoma carrying BRAF mutations represent a still unmet medical need as success of BRAF inhibitors is limited by development of resistance. Nicotinamide phosphoribosyltransferase (NAMPT) is a key enzyme in NAD biosynthesis. An extracellular form (eNAMPT) possesses cytokine-like functions and is up-regulated in inflammatory disorders, including cancer. Here we show that eNAMPT is actively released in culture supernatants of melanoma cell lines. Furthermore, cells that become resistant to BRAF inhibitors (BiR) show a significant increase of eNAMPT levels. Plasma from mice xenografted with BiR cell lines contain higher eNAMPT levels compared to tumor-free animals. Consistently, eNAMPT levels are elevated in 113 patients with BRAF-mutated metastatic melanoma compared to 50 with localized disease or to 38 healthy donors, showing a direct correlation with markers of tumor burden, such as LDH, or aggressive disease (such as PD-L1). eNAMPT concentrations decrease in response to therapy with BRAF/MEK inhibitors, but increase again at progression, as inferred from the serial analysis of 50 patients. Lastly, high eNAMPT levels correlate with a significantly shorter overall survival.

Our findings suggest that eNAMPT is a novel marker of tumor burden and response to therapy in patients with metastatic melanoma carrying BRAF mutations.

THE ASSOCIATION OF PLASMA LEVELS OF miR-34a AND miR-149 WITH OBESITY AND INSULIN RESISTANCE IN OBESE CHILDREN AND ADOLESCENTS

CONTEXT

MicroRNAs (miRNAs) are short noncoding RNAs involved in posttranscriptional regulation of gene expression that influence various cellular functions including glucose and lipid metabolism and adipocyte differentiation.

OBJECTIVE

The aim of this study was to evaluate the levels of miR-34a and miR-149 and their relationship with metabolic parameters in obese children and adolescents.

DESIGN

Seventy children and adolescents were enrolled in the study. Plasma levels of microRNAs were evaluated by real-time PCR using SYBR green and analyzed by ΔCt method. Plasma concentrations of visfatin and insulin were measured by ELISA method. Glucose and lipid profile were determined colorimetrically. HOMA-IR was calculated and used as an index of insulin resistance (IR).

RESULTS

miR-34a was significantly lower in subjects with insulin resistance compared to obese children with normal insulin sensitivity. There was an inverse relationship between miR-34a levels and both insulin and HOMA-IR. On the other hand, miR-149 was significantly correlated with visfatin. There was no significant difference in miR-34a and miR-149 between obese and normal weight subjects.

CONCLUSIONS

miR-34a is associated with insulin and HOMA-IR and thus seems to be involved in IR. miR-149 is inversely associated with visfatin levels which could be indicative of anti-inflammatory effect of this miRNA.

Can adipokines serum levels be used as biomarkers of hand osteoarthritis?

PURPOSE

To evaluate serum levels of visfatin, resistin and adiponectin in patients with erosive (E) and non-erosive (NE) osteoarthritis (OA) of the hand (HOA) compared to normal controls (NC).

METHODS

94 outpatients with E HOA and NE HOA and 21 NC were enrolled. The radiological assessment of both hands was performed according to the Kellgren-Lawrence and Kallman score. Patients were divided into two subsets (lone HOA or generalized OA) based on clinically OA involvement of knee and hip. Serum visfatin, resistin and adiponectin levels were determined by ELISA assay.

RESULTS

Visfatin was significantly higher in E HOA patients in comparison to NC and NE HOA group. Resistin showed a significant increase in both E HOA and NE HOA groups versus NC, in particular in generalized OA. No significant differences among groups were found in adiponectin. The Kallman score was more severe in the two subsets of E HOA patients compared to NE HOA.

CONCLUSIONS

This study showed increased levels of resistin in erosive and non-erosive HOA, and higher visfatin levels in E HOA in comparison to NE HOA. These data suggest the adipokines possible role in the pathogenesis of HOA and their potential usefulness as biomarkers of the disease.

Promotion of anoxia-reoxygenation-induced inflammation and permeability enhancement by nicotinamide phosphoribosyltransferase-activated MAPK signaling in human umbilical vein endothelial cells

Previous studies have demonstrated that nicotinamide phosphoribosyltransferase (NAMPT) promoted inflammation and permeability of vascular endothelial cells following cardiopulmonary bypass (CPB). In addition, mitogen-activated protein kinase (MAPK) signaling was activated and contributed to these cell responses. However, the mechanism by which NAMPT regulates cellular inflammation and permeability remains unknown, and whether NAMPT regulates MAPK signaling during this process is also not clear. The present study established an anoxia-reoxygenation (A-R) model using human umbilical vein endothelial cells (HUVECs) and investigated the regulation of MAPK signaling by NAMPT by using small RNA transfection, ELISA and western blot analysis. The results demonstrated that A-R significantly induced the expression levels of NAMPT and cellular permeability-associated proteins, and the release of several inflammatory factors. Furthermore, calcium and MAPK signaling were evidently increased. When the A-R cells were transfected with NAMPT small interfering RNA, the expression of cellular permeability-associated proteins was downregulated, the release of inflammatory factors was decreased, and calcium and MAPK signaling was blocked. These data suggest that NAMPT may activate MAPK signaling to promote A-R-induced inflammation and permeability enhancement of HUVECs. Therefore, the current study indicates that NAMPT may be a potential drug target for A-R-induced endothelial cell injury subsequent to CPB.

Visfatin Is Actively Secreted In Vitro From U-937 Macrophages, but Only Passively Released From 3T3-L1 Adipocytes and HepG2 Hepatocytes

Visfatin is a multi-functional molecule that can act intracellularly and extracellularly as an adipokine, cytokine and enzyme. One of the main questions concerning visfatin is the mechanism of its secretion; whether, how and from which cells visfatin is released. The objective of this in vitro study was to observe the active secretion of visfatin from 3T3-L1 preadipocytes and adipocytes, HepG2 hepatocytes, U-937, THP-1 and HL-60 monocytes and macrophages. The amount of visfatin in media and cell lysate was always related to the intracellular enzyme, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), to exclude the passive release of visfatin. Visfatin was not found in media of 3T3-L1 preadipocytes. In media of 3T3-L1 adipocytes and HepG2 hepatocytes, the ratio of visfatin to the amount of GAPDH was identical to cell lysates. Hence, it is likely that these cells do not actively secrete visfatin in a significant manner. However, we found that significant producers of visfatin are differentiated macrophages and that the amount of secreted visfatin depends on used cell line and it is affected by the mode of differentiation. Results show that 3T3-L1 adipocytes and HepG2 hepatocytes released visfatin only passively during the cell death. U-937 macrophages secrete visfatin in the greatest level from all of the tested cell lines.