α-Mangostin reduced the viability of A594 cells in vitro by provoking ROS production through downregulation of NAMPT/NAD.

α-Mangostin (MAN) is a bioactive compound isolated from the inedible pericarp of a tropical fruit mangosteen (Garcinia mangostana Linn). It exhibits notable therapeutic potentials on lung cancers, but the underlying mechanisms are still largely unknown. This study was designed to further explore the mechanisms involved in cytotoxicity of MAN on A549 cells. Apoptosis and cell cycle distribution were analyzed by flow cytometry methods. The fluorescent probes DCFH-DA and JC-1 were used to assess the intracellular reactive oxidative species (ROS) and mitochondrial membrane potential statuses, respectively. The regulation of MAN on relevant pathways was investigated by immunoblotting assays. The results obtained indicated that MAN caused significant apoptosis and cell cycle arrest in A549 cells, which eventually resulted in inhibition on cell proliferation in vitro. All these phenomena were synchronized with escalated oxidative stress and downregulation of nicotinamide phosphoribosyltransferase/nicotinamide adenine dinucleotide (NAMPT/NAD). Supplementation with nicotinamide mononucleotide (NMN) and N-acetylcysteine (NAC) efficiently eased MAN-induced ROS accumulation, and potently antagonized MAN-elicited apoptosis and cell cycle arrest. The pro-apoptotic effect of MAN was further confirmed by increased expressions of cleaved caspase 3, 6, 7, and 9, and its effect on cell cycle progression was validated by the altered expressions of p-p38, p-p53, CDK4, and cyclin D1. The immunoblotting assays also demonstrated that NAC/NMN effectively restored these molecular changes elicited by MAN treatment. Collectively, this study revealed a unique anti-tumor mechanism of MAN by provoking ROS production through downregulation of NAMPT/NAD signaling and further validated MAN as a potential therapeutic reagent for lung cancer treatment.

Nicotinamide phosphoribosyltransferase is a molecular target of potent anticancer agents identified from phenotype-based drug screening.

Phenotypic screening in drug discovery has been revived with the expectation of providing promising lead compounds and drug targets and improving the success rate of drug approval. However, target identification remains a major bottleneck in phenotype-based drug discovery. We identified the lead compounds K542 and K405 with a selective inhibition of cell viability against sphingosine-1-phosphate lyase 1 (SGPL1)-transduced ES-2 cells by phenotypic screening. We therefore performed an in vivo pharmacological examination and observed the antitumor activity of K542 in an HT-1080 tumor-bearing mouse xenograft model. SGPL1 was expected to be a therapeutic target in some cancers, suggesting that these lead molecules might be promising candidates; however, their mechanisms of action still remain unexplained. We therefore synthesized the affinity probe Ind-tag derived from K542 and identified the proteins binding to Ind-tag via a pull-down experiment. Proteomics and biochemical analyses revealed that the target molecule of these lead compounds was Nicotinamide phosphoribosyltransferase (NAMPT). We established K542-resistant DLD-1 and HT-1080 cells, and genetic analyses of these cells identified a missense mutation in the NAMPT-encoding gene. This enzymatic experiment clearly showed that K393 exerts enzymatic inhibition against NAMPT. These proteomics, genetics and biochemical analyses clarified that compounds K542 and K405 were NAMPT inhibitors.

NAMPT inhibitor protects ischemic neuronal injury in rat brain via anti-neuroinflammation.

Nicotinamide phosphoribosyltransferase (NAMPT) is an important neuroprotective factor in cerebral ischemia, and it has been reported that NAMPT inhibitors can aggravate neuronal injury in the acute phase. However, because it is a cytokine, NAMPT participates in many inflammatory diseases in the peripheral system, and its inhibitors have therapeutic effects. Following cerebral ischemia, the peripheral and resident inflammatory and immune cells produce many pro-inflammatory mediators in the ischemic area, which induce neuroinflammation and impair the brain. However, the effects of NAMPT inhibitors in the neuroinflammation after ischemic brain injury remain unknown. Here, we found that FK866, a potent NAMPT inhibitor, decreased the level of TNF-α, NAMPT and IL-6 in the ischemic brain tissue one day after middle-cerebral-artery occlusion and reperfusion (MCAO/R), improved neurological dysfunction, decreased infarct volume and neuronal loss, and inhibited microgliosis and astrogliosis 14days after MCAO/R. The expression of NAMPT protein was induced in Iba1-positive microglia/macrophages in the ischemia core 14days after MCAO/R. In vitro studies show that oxygen-glucose deprivation and recovery (OGD/R) activate microglia. Activated microglia increased the activity of NF-κB, increased the mRNA synthesis of TNF-α, NAMPT and IL-6, and increased the secretion of TNF-α, NAMPT and IL-6. On the other hand, NAMPT can act synergistically with other cytokines and activate microglia. FK866 strongly inhibited these changes and alleviated OGD/R-induced activation of microglia. As such, NAMPT is a crucial determinant of cellular inflammation after cerebral ischemia. NAMPT inhibitors are novel compounds to protect neuronal injury from ischemia via anti-inflammatory effects.

Effects of antihypertensive treatment on plasma apelin, resistin, and visfatin concentrations.

INTRODUCTION Adipose tissue has been recently recognized as an endocrine organ secreting a number of adipokines contributing to the development of atherosclerosis, hypertension, chronic kidney disease, endothelial dysfunction, insulin resistance, and vascular remodeling. OBJECTIVES The aim of this study was to determine whether treatment with a ß-blocker, calcium antagonist, thiazide-like diuretic, or angiotensin II receptor type 1 influences plasma concentrations of apelin, resistin, and visfatin in obese hypertensive patients. PATIENTS AND METHODS The study included 84 obese patients with essential hypertension. One control group included obese subjects without hypertension, and the other, lean subjects without hypertension. Patients with hypertension were randomized into 4 groups treated for 6 weeks with bisoprolol, amlodipine, indapamide, or candesartan, respectively. RESULTS Mean daily plasma apelin concentrations in patients treated with amlodipine was significantly higher than the baseline values, whereas the difference in plasma apelin concentrations in other treatment groups was not significant. Mean daily plasma resistin concentrations were significantly lower after 6-week treatment with amlodipine, bisoprolol, or indapamide compared with the baseline values. In patients treated with candesartan, no significant differences in resistin concentrations were shown. After 6-week treatment with bisoprolol, mean daily plasma concentrations of visfatin were significantly lower compared with the baseline values. Treatment with amlodipine, candesartan, or indapamide did not significantly affect plasma visfatin levels. CONCLUSIONS Antihypertensive treatment exerts significant and varied effects on adipokine secretion in obese hypertensive patients. Changes in apelin secretion, caused by the use of different antihypertensive drugs, may protect the cardiovascular system and kidneys. The involvement of adipokins in the mechanism of diverse protective effects of antihypertensive drugs, independently of the effect on blood pressure, requires further research.

Nicotine may affect the secretion of adipokines leptin, resistin, and visfatin through activation of KATP channel.

OBJECTIVE: It has been confirmed that adipokines are associated with atherosclerosis. Cigarette smoking was found to possibly influence adipokine secretion. However, the precise role of smoking in adipokine secretion and the underlying mechanisms are largely unknown. The aim of this study was to determine whether nicotine, the principal active ingredient of cigarettes, can influence adipokine secretion and its potential mechanism. METHODS: The present study consecutively enrolled 96 men, including 50 smokers with early atherosclerosis and 46 nonsmokers. Serum adipokines, including leptin, resistin, and visfatin, were determined with enzyme-linked immunosorbent assay in all participants. Furthermore, the effect of nicotine on secretion of these adipokines was examined in differentiated 3T3-L1 preadipocytes under the conditions of ATP-dependent potassium (KATP) channel blocked or unblocked. RESULTS: Compared with the control group, serum levels of leptin, resistin, and visfatin in smokers were significantly higher. In 3T3-L1 adipocytes, nicotine treatment significantly increased the levels of these adipokines (P = 0.014, 0.001, and 0.029, respectively). When the KATP channel was blocked, secretion of resistin and visfatin was reduced (P < 0.001), but no change was found in the leptin secretion (P = 0.522). CONCLUSIONS: Nicotine may affect the secretion of adipokines leptin, resistin, and visfatin through activation of KATP channel.