Metrnl deficiency retards skin wound healing in mice by inhibiting AKT/eNOS signaling and angiogenesis.

Meteorin-like (Metrnl) is a novel secreted protein with various biological activities. In this study, we investigated whether and how Metrnl regulated skin wound healing in mice. Global Metrnl gene knockout mice (Metrnl-/-) and endothelial cell-specific Metrnl gene knockout mice (EC-Metrnl-/-) were generated. Eight-mm-diameter full-thickness excisional wound was made on the dorsum of each mouse. The skin wounds were photographed and analyzed. In C57BL/6 mice, we observed that Metrnl expression levels were markedly increased in skin wound tissues. We found that both global and endothelial cell-specific Metrnl gene knockout significantly retarded mouse skin wound healing, and endothelial Metrnl was the key factor affecting wound healing and angiogenesis. The proliferation, migration and tube formation ability of primary human umbilical vein endothelial cells (HUVECs) were inhibited by Metrnl knockdown, but significantly promoted by addition of recombinant Metrnl (10 ng/mL). Metrnl knockdown abolished the proliferation of endothelial cells stimulated by recombinant VEGFA (10 ng/mL) but not by recombinant bFGF (10 ng/mL). We further revealed that Metrnl deficiency impaired VEGFA downstream AKT/eNOS activation in vitro and in vivo. The damaged angiogenetic activity in Metrnl knockdown HUVECs was partly rescued by addition of AKT activator SC79 (10 µM). In conclusion, Metrnl deficiency retards skin wound healing in mice, which is related to impaired endothelial Metrnl-mediated angiogenesis. Metrnl deficiency impairs angiogenesis by inhibiting AKT/eNOS signaling pathway.

Humanized cerebral organoids-based ischemic stroke model for discovering of potential anti-stroke agents.

Establishing a stoke experimental model, which is better in line with the physiology and function of human brain, is the bottleneck for the development of effective anti-stroke drugs. A three-dimensional cerebral organoids (COs) from human pluripotent stem cells can mimic cell composition, cortical structure, brain neural connectivity and epigenetic genomics of in-vivo human brain, which provides a promising application in establishing humanized ischemic stroke model. COs have been used for modeling low oxygen condition-induced hypoxic injury, but there is no report on the changes of COs in response to in vitro oxygen-glucose deprivation (OGD)-induced damage of ischemic stroke as well as its application in testing anti-stroke drugs. In this study we compared the cell composition of COs at different culture time and explored the cell types, cell ratios and volume size of COs at 85 days (85 d-CO). The 85 d-CO with diameter more than 2 mm was chosen for establishing humanized ischemic stroke model of OGD. By determining the time-injury relationship of the model, we observed aggravated ischemic injury of COs with OGD exposure time, obtaining first-hand evidence for the damage degree of COs under different OGD condition. The sensitivity of the model to ischemic injury and related treatment was validated by the proven pan-Caspase inhibitor Z-VAD-FMK (20 µM) and Bcl-2 inhibitor navitoclax (0.5 µM). Neuroprotective agents edaravone, butylphthalide, P7C3-A20 and ZL006 (10 µM for each) exerted similar beneficial effects in this model. Taken together, this study establishes a humanized ischemic stroke model based on COs, and provides evidence as a new research platform for anti-stroke drug development.

Pharmacological characterization of MT-1207, a novel multitarget antihypertensive agent.

Hypertension is a serious public health problem worldwide. MT-1207, chemically named 3-(4-(4-(1H-benzotriazole-1-yl)butyl)piperazine-1-yl) benzisothiazole hydrochloride, is a new chemical entity that has entered into clinical trial as antihypertensive agent in China. In this paper we report the pharmacological profile of MT-1207 regarding its acute, subacute, and long-term effects on hypertensive animal models, and its actions on isolated organs in vitro as well as its molecular targets. Blood pressure (BP) was measured in conscious animals; amlodipine was taken as a positive control drug. We showed that both single dose of MT-1207 (1.25-20 mg/kg, ig) in spontaneously hypertensive rats (SHR) and MT-1207 (0.25-6 mg/kg, ig) in two-kidney one-clip (2K1C) dogs dose-dependently decreased BP. MT-1207 quickly decreased BP within 5 min after administration; the hypotensive effect lasted for 8 and 12 h, respectively, in SHR and 2K1C dogs without reflex increase in heart rate. Multiple doses of MT-1207 (5 mg · kg-1 · d-1 in SHR; 2 mg · kg-1 · d-1 in 2K1C dogs, for 7 days) significantly decreased BP, slightly reduced heart rate, and both of them recovered after withdrawal. Long-term administration of MT-1207 (10 mg · kg-1 · d-1 for 4 months or more time) produced a stable BP reduction, improved baroreflex sensitivity, reduced renal and cardiovascular damage in SHR, and delayed stroke occurrence and death in stroke-prone SHR. In isolated rat aortic rings precontracted by adrenaline, KCl, noradrenaline or 5-hydroxytryptamine (5-HT), MT-1207 (10-9-10-4 M) caused concentration-dependent relaxation. In a panel of enzyme activity or radioligand binding assays of 87 molecular targets, MT-1207 potently inhibited adrenergic α1A, α1B, α1D, and 5-HT2A receptors with Ki < 1 nM. The antagonism of MT-1207 against these receptors was confirmed in isolated rabbit arteries. We conclude that MT-1207 is a novel and promising single-molecule multitarget agent for hypertension treatment to reduce hypertensive organ damage and stroke mortality.

Microstructural Investigation and On-Site Repair of Thin Pd-Ag Alloy Membranes.

Pd membranes act in an important role in H2 purification and H2 production in membrane reactors. Pd-Ag alloy membranes fabricated by consecutive electroless- and electroplating process on alumina tubes exhibited good stability under stringent heating/cooling cycles at a ramp rate of 10 K/min, imitating practical fast initiation or emergency shutdown conditions. Bilayer Pd-Ag membranes can form dense and uniform alloy after thermal treatment for 24 h at 823 K under H2 atmosphere, despite a porous structure due to the development of liquid-like properties above Tamman temperature to enforce the migrativity. On the contrary, alloying under N2 atmosphere resulted in a Pd-enriched layer. This led to a lower H2 flux but superior thermal stability compared to that alloying under H2 atmosphere. The trilayer approach of electroless-plated Pd, electro-polated Ag and electroless-plated Pd is not suitable to achieve homogeneous Pd-Ag alloys, which, on the other hand, presented the occurrence of a small gap between top Pd layer and middle Ag layer, probably due to insufficient wetting during plating process. An on-site repair treatment in analogous to MOCVD (Metal-organic Chemical Vapor Deposition) process was first proposed to extend the lifetime of Pd-Ag membrane, i.e., by vaporizing, and subsequent decomposition of Ag(OOCC2F5) powders to "preferentially" block the pinholes under vacuum and at working temperature of ca. 473-673 K, which effectively reduced the N2 flux by 57.4% compared to the initial value. The H2 flux, however, declined by 16.7% due to carbon deposition on the membrane surface, which requires further investigation. This approach shows some potential for on-site repair without disassembly or cooling to room temperature.

Clinical characteristics associated with long-term viral shedding in patients with coronavirus disease 2019.

BACKGROUND: To delineate the clinical characteristics associated with long-term viral shedding (>21 days) in patients with coronavirus disease 2019 (COVID-19). METHODS: In this retrospective study, factors associated with long-term (>21 days) severe acute respiratory coronavirus 2 (SARS-CoV-2) RNA shedding were evaluated in a conhort of 609 patients from two hospitals in Wuhan. RESULTS: The median duration of SARS-CoV-2 viral shedding was 19 days (interquartile range, 10-28 days) among all patients. There were 42% of patients having prolonged viral shedding time (>21 days), in which the longest viral shedding time was 58 days. When comparing patients with early (≤21 days) and late viral RNA clearance (>21 days), prolonged viral shedding was associated with age <65 (P=0.015), female sex (P=0.028), cough (P=0.025), fatigue (P=0.035), sore throat (P=0.013), aspartate aminotransferase (P=0.038), procalcitonin (P=0.010), albumin (P=0.003), D-dimer (P=0.011), lung involvement (P=0.014), reticular shadow (P<0.001) and lung consolidation (P=0.004). Age range (<65 years) (odds ratio [OR], 1.46 [95% CI, 1.05-2.03]) and female sex (odds ratio [OR], 1.40 [95% CI, 1.00-1.94]) were independent risk factors. CONCLUSIONS: Long-term viral shedding (>21 days) is not a rare phenomenon among COVID-19 infectious patients. Age range (<65) and female sex are independent risk factors for long-term viral shedding. Early antiviral treatment should be considered for COVID-19 patients with such risk factors. Further study should be conducted to know the infectivity of patients with long-term viral shedding in order to develop reasonable control measures.

Cerebral organoids transplantation improves neurological motor function in rat brain injury.

BACKGROUND AND PURPOSE: Cerebral organoids (COs) have been used for studying brain development, neural disorders, and species-specific drug pharmacology and toxicology, but the potential of COs transplantation therapy for brain injury remains to be answered. METHODS: With preparation of traumatic brain injury (TBI) model of motor dysfunction, COs at 55 and 85 days (55 and 85 d-CO) were transplanted into damaged motor cortex separately to identify better transplantation donor for brain injury. Further, the feasibility, effectiveness, and underlying mechanism of COs transplantation therapy for brain injury were explored. RESULTS: 55 d-CO was demonstrated as better transplantation donor than 85 d-CO, evidenced by more neurogenesis and higher cell survival rate without aggravating apoptosis and inflammation after transplantation into damaged motor cortex. Cells from transplanted COs had the potential of multilinage differentiation to mimic in-vivo brain cortical development, support region-specific reconstruction of damaged motor cortex, form neurotransmitter-related neurons, and migrate into different brain regions along corpus callosum. Moreover, COs transplantation upregulated hippocampal neural connection proteins and neurotrophic factors. Notably, COs transplantation improved neurological motor function and reduced brain damage. CONCLUSIONS: This study revealed 55 d-CO as better transplantation donor and demonstrated the feasibility and efficacy of COs transplantation in TBI, hoping to provide first-hand preclinical evidence of COs transplantation for brain injury.

Aggravated ulcerative colitis caused by intestinal Metrnl deficiency is associated with reduced autophagy in epithelial cells.

Metrnl is a newly identified secreted protein highly expressed in the intestinal epithelium. This study aimed to explore the role and mechanism of intestinal epithelial Metrnl in ulcerative colitis. Metrnl-/- (intestinal epithelial cell-specific Metrnl knockout) mice did not display any phenotypes of colitis under basal conditions. However, under administration of 3% dextran sodium sulfate (DSS) drinking water, colitis was more severe in Metrnl-/- mice than in WT mice, as indicated by comparisons of body weight loss, the presence of occult or gross blood per rectum, stool consistency, shrinkage in the colon, intestinal damage, and serum levels of inflammatory factors. DSS-induced colitis activated autophagy in the colon. This activation was partially inhibited by intestinal epithelial Metrnl deficiency, as indicated by a decrease in Beclin-1 and LC3-II/I and an increase in p62 in DSS-treated Metrnl-/- mice compared with WT mice. These phenomena were further confirmed by observation of autophagosomes and immunofluorescence staining for LC3 in epithelial cells. The autophagy-related AMPK-mTOR-p70S6K pathway was also activated in DSS-induced colitis, and this pathway was partially blocked by intestinal epithelial Metrnl deficiency, as indicated by a decrease in AMPK phosphorylation and an increase in mTOR and p70S6K phosphorylation in DSS-treated Metrnl-/- mice compared with WT mice. Therefore, Metrnl deficiency deteriorated ulcerative colitis at least partially through inhibition of autophagy via the AMPK-mTOR-p70S6K pathway, suggesting that Metrnl is a therapeutic target for ulcerative colitis.

Cerebral Organoids Repair Ischemic Stroke Brain Injury.

Stroke is the second leading cause of death and main cause of disability worldwide, but with few effective therapies. Although stem cell-based therapy has been proposed as an exciting regenerative medicine strategy for brain injury, there are limitations. The developed cerebral organoids (COs) represent a promising transplantation source for stroke that remains to be answered. Here, we transplanted COs at 55 days and explored the feasibility in the rat middle cerebral artery occlusion (MCAO) model of stroke. COs transplantation at 6 h or even 24 h after MCAO significantly reduces brain infarct volume and improves neurological motor function. Transplanted COs show the potential of multilineage differentiation to mimic in vivo cortical development, support motor cortex region-specific reconstruction, form neurotransmitter-related neurons, and achieve synaptic connection with host brain via in situ differentiation and cell replacement in stroke. Cells from transplanted COs show extensive migration into different brain regions along corpus callosum. The mechanisms underlying COs transplantation therapy are also associated with enhanced neurogenesis, synaptic reconstruction, axonal regeneration and angiogenesis, and decreased neural apoptosis with more survival neurons after stroke. Moreover, COs transplantation promotes predominantly exogenous neurogenesis in the transplantation periphery of ipsilateral cortex and predominantly endogenous neurogenesis in the hippocampus and subventricular zone. Together, we demonstrate the efficacy and underlying mechanisms of COs transplantation in stroke. This preliminary but promising study provides first-hand preclinical evidence for COs transplantation as a potential and effective intervention for stroke treatment.

Nicotinamide phosphoribosyltransferase aggravates inflammation and promotes atherosclerosis in ApoE knockout mice.

Nicotinamide phosphoribosyltransferase (Nampt) is the rate-limiting enzyme of nicotinamide adenine dinucleotide (NAD) salvage biosynthesis in mammals, and is involved in fundamental physiological processes and pathophysiology of many diseases. Thus far, however, the role of Nampt in atherosclerosis development is still in debate. In this study, we crossed global Nampt transgenic mice (Nampt-Tg) with a well-established atherosclerosis animal model (ApoE knockout mice, ApoE-/-) to generate ApoE-/-;Nampt-Tg mice and investigated the effects of Nampt overexpression on atherosclerosis development in ApoE-/- mice. Both ApoE-/- and ApoE-/-;Nampt-Tg mice were fed with a pro-atherosclerotic high-fat diet (HFD) for 16 weeks. Their serum lipid contents and atherosclerotic lesion were assessed. The results showed that there was no significant difference in body weight or serum levels of glucose, total cholesterol, triglycerides, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol between the two strains of mice, but ApoE-/-;Nampt-Tg mice had a significantly higher level of serum non-esterified fatty acid. Compared with ApoE-/- mice, ApoE-/-;Nampt-Tg mice displayed significantly increased atherosclerotic lesion area and thickness, lower collagen content, decreased collagen I/III ratio (collagen immaturation), increased number of apoptotic cells, and enhanced activities of caspase-3, caspase-8, and caspase-9. Moreover, macrophage infiltration (F4/80 staining), tumor necrosis factor signaling, and chemokines expression (ICAM-1 and CXCR-4) were all activated in aortic atherosclerotic plaque of ApoE-/-;Nampt-Tg mice compared with ApoE-/- mice. Our results provide in vivo evidence that Nampt transgene aggravates atherosclerotic inflammation and promotes atherosclerosis development in ApoE-/- mice.

[The effects of climate change on isoprene emission rate from leaves of Pleioblastus amarus in different regions.] / 气候变化影响下不同地区苦竹异戊二烯排放速率对比.

Based on the RCP2.6, RCP4.5, RCP6.0 and RCP8.5 climate change scenarios produced by the global climate model NorESM1-M and plant isoprene emissions model, the effects of climate change on the isoprene emission rate from leaves of Pleioblastus amarus in Yixing City of Jiangsu Province, Longmen County of Guangdong Province, Yulong Naxi Autonomous County of Yunnan Province and Wanyuan City of Sichuan Province were simulated. The differences of isoprene emission rate from leaves of P. amarus distributed in four regions were compared under future climate change scenarios. The results showed that mean annual air temperature would increase, annual precipitation and radiation intensity would greatly fluctuate, with the coexistence of increasing and decreasing trends in the four regions. In the baseline scenario, daily mean emission rate of isoprene from leaves of P. amarus was 71-470 µg·g-1·d-1, and annual mean value was 25954-171231 µg·g-1·a-1. The daily and annual emission rates in the four regions decreased with the order of Longmen, Yixing, Wanyuan and Yulong. Compared with the baseline scenario, daily mean emission rate of isoprene from leaves of P. amarus was about 4-45 µg·g-1·d-1 higher in future climate change scenario, and which was about 23, 29, 4, and 14 µg·g-1·d-1 higher than that in baseline in Yixing, Longmen, Yulong and Wanyuan, respectively. In addition, the emission rate of isoprene from leaves of P. amarus was more than 5% higher in the future climate change scenario than that in the baseline scenario, which was higher in Wanyuan and Yixing (>13%) than and lower in Longmen and Yulong (>5%). All the four regions reached the highest rate under RCP8.5 scenario (increased by about 11%-18%). Compared with the baseline scenario, annual emission rate of isoprene in the future climate change scenario was about 1500-17000 µg·g-1·a-1, and which was about 8560-13208 µg·g-1·a-1 higher in Yixing, 10862-16131 µg·g-1·a-1 higher in Longmen, 1574-3028 µg·g-1·a-1 higher in Yulong, 5288-8532 µg·g-1·a-1 higher in Wanyuan. In addition, the increasing rate of annual isoprene emission rates was 6%-14%. The rates in Yixing (8%-12%) and Wanyuan (8%-14%) were higher than that in the other two regions, the rate in Yulong (6%-12% increase) was the lowest, with all four regions increasing substantially (9%-14%) under RCP8.5 scenario. The results suggested that climate change would have different effects on the rate of isoprene emissions from leaves of P. amarus distributed in diffe-rent regions.

"Modified" Liquid⁻Liquid Displacement Porometry and Its Applications in Pd-Based Composite Membranes.

For H2 separation by Pd-based composite membranes, the pore mouth size distribution of the porous support immediately affects the quality of the deposited layer, including continuity and defect/pinhole formation. However, there is a lack of convenient and effective methods for characterization of pore mouth size of porous supports as well as of defect distribution of dense Pd-based composite membranes. Here we introduce a novel method by modifying conventional liquid⁻liquid displacement porometry. When the pore tunnels are filled with Liquid B and the outer surface is occupied by Liquid A, the reopening of the pore mouth depends on the pressure of Liquid B and the interfacial tension at the position of the pore mouth, from which the pore mouth size can be determined according to the Young⁻Laplace equation. Our experimental tests using this method with model samples show promising results, which are well supported by those obtained using FESEM (fild emission scanning electron microscope), AFM (atomic force microscope), and conventional liquid⁻liquid displacement porometry. This novel method can provide useful information for not only surface coatings on porous substrates but also for modification of dense membrane defects; thus, broad utilizations of this technique can be expected in future study.

Crystal structure-based comparison of two NAMPT inhibitors.

Inhibition of nicotinamide phosphoribosyltransferase (NAMPT) is a novel strategy for cancer therapy, but only two inhibitors of NAMPT (FK866 and CHS828) have progressed into clinical trials. This study seeks to compare a novel potent NAMPT inhibitor, MS0, with a classical inhibitor FK866 in their biological activity and molecular binding mode, thereby contributing to future chemical optimization and a further understanding of the action mode of NAMPT inhibitors. The IC50 values of MS0 and FK866 in inhibition of recombinant human NAMPT activity were 9.08±0.90 and 1.60±0.32 nmol/L, respectively. Consistently, FK866 exerted better antiproliferation in 6 human cancer cell lines (HepG2, A2780, 95-D, A549, U2OS and U266) than MS0 with IC50 values nearly 12-fold to 225-fold lower than those of MS0. Co-crystal structures of wild-type human NAMPT complexed with MS0 or FK866 were elucidated, which revealed that MS0 did not interact with Ser241. The hydrogen bond mediated by crystallographic water between MS0 and His191 or Val350 of NAMPT did not exist in FK866. Instead, FK866 exhibited hydrophobic interactions with Arg349. Based on the activity assays and crystal structure analyses, we elaborate the reason why the antiproliferation activity of MS0 was not as good as that of FK866, which would contributes to the current understanding of the mode of action of NAMPT inhibitors and will also contribute to further development of anticancer drugs in the future.

Organoid technology for brain and therapeutics research.

Brain is one of the most complex organs in human. The current brain research is mainly based on the animal models and traditional cell culture. However, the inherent species differences between humans and animals as well as the gap between organ level and cell level make it difficult to study human brain development and associated disorders through traditional technologies. Recently, the brain organoids derived from pluripotent stem cells have been reported to recapitulate many key features of human brain in vivo, for example recapitulating the zone of putative outer radial glia cells. Brain organoids offer a new platform for scientists to study brain development, neurological diseases, drug discovery and personalized medicine, regenerative medicine, and so on. Here, we discuss the progress, applications, advantages, limitations, and prospects of brain organoid technology in neurosciences and related therapeutics.

Small Molecule Inhibitors Simultaneously Targeting Cancer Metabolism and Epigenetics: Discovery of Novel Nicotinamide Phosphoribosyltransferase (NAMPT) and Histone Deacetylase (HDAC) Dual Inhibitors.

Cancer metabolism and epigenetics are among the most intensely pursued research areas in anticancer drug discovery. Here we report the first small molecules that simultaneously inhibit nicotinamide phosphoribosyltransferase (NAMPT) and histone deacetylase (HDAC), two important targets of cancer metabolism and epigenetics, respectively. Through iterative structure-based drug design, chemical synthesis, and biological assays, a highly potent dual NAMPT and HDAC inhibitor was successfully identified. Compound 35 possessed excellent and balanced activities against both NAMPT (IC50 = 31 nM) and HDAC1 (IC50 = 55 nM). It could effectively induce cell apoptosis and autophagy and ultimately led to cell death. Importantly, compound 35 showed excellent in vivo antitumor efficacy in the HCT116 xenograft model. This proof-of-concept study demonstrates the feasibility of discovering an inhibitor targeting cancer metabolism and epigenetics and provides an efficient strategy for multitarget antitumor drug discovery.

Neuroprotective Efficacy of an Aminopropyl Carbazole Derivative P7C3-A20 in Ischemic Stroke.

AIM: NAMPT is a novel therapeutic target of ischemic stroke. The aim of this study was to investigate the effect of a potential NAMPT activator, P7C3-A20, an aminopropyl carbazole derivative, on ischemic stroke. METHODS: In vitro study, neuron protection effect of P7C3-A20 was investigated by co-incubation with primary neurons subjected to oxygen-glucose deprivation (OGD) or oxygen-glucose deprivation/reperfusion (OGD/R) injury. In vivo experiment, P7C3-A20 was administrated in middle cerebral artery occlusion (MCAO) rats and infarct volume was examined. Lastly, the brain tissue nicotinamide adenine dinucleotide (NAD) levels were detected in P7C3-A20 treated normal or MCAO mice. RESULTS: Cell viability, morphology, and Tuj-1 staining confirmed the neuroprotective effect of P7C3-A20 in OGD or OGD/R model. P7C3-A20 administration significantly reduced cerebral infarction in MCAO rats. Moreover, brain NAD levels were elevated both in normal and MCAO mice after P7C3-A20 treatment. CONCLUSIONS: P7C3-A20 has neuroprotective effect in cerebral ischemia. The study contributes to the development of NAMPT activators against ischemic stroke and expands the horizon of the neuroprotective effect of aminopropyl carbazole chemicals.

Hepatic NAD(+) deficiency as a therapeutic target for non-alcoholic fatty liver disease in ageing.

BACKGROUND AND PURPOSE: Ageing is an important risk factor of non-alcoholic fatty liver disease (NAFLD). Here, we investigated whether the deficiency of nicotinamide adenine dinucleotide (NAD(+) ), a ubiquitous coenzyme, links ageing with NAFLD. EXPERIMENTAL APPROACH: Hepatic concentrations of NAD(+) , protein levels of nicotinamide phosphoribosyltransferase (NAMPT) and several other critical enzymes regulating NAD(+) biosynthesis, were compared in middle-aged and aged mice or patients. The influences of NAD(+) decline on the steatosis and steatohepatitis were evaluated in wild-type and H247A dominant-negative, enzymically-inactive NAMPT transgenic mice (DN-NAMPT) given normal or high-fat diet (HFD). KEY RESULTS: Hepatic NAD(+) level decreased in aged mice and humans. NAMPT-controlled NAD(+) salvage, but not de novo biosynthesis pathway, was compromised in liver of elderly mice and humans. Given normal chow, middle-age DN-NAMPT mice displayed systemic NAD(+) reduction and had moderate NAFLD phenotypes, including lipid accumulation, enhanced oxidative stress, triggered inflammation and impaired insulin sensitivity in liver. All these NAFLD phenotypes, especially release of pro-inflammatory factors, Kupffer cell accumulation, monocytes infiltration, NLRP3 inflammasome pathway and hepatic fibrosis (Masson's staining and α-SMA staining), deteriorated further under HFD challenge. Oral administration of nicotinamide riboside, a natural NAD(+) precursor, completely corrected these NAFLD phenotypes induced by NAD(+) deficiency alone or HFD, whereas adenovirus-mediated SIRT1 overexpression only partially rescued these phenotypes. CONCLUSIONS AND IMPLICATIONS: These results provide the first evidence that ageing-associated NAD(+) deficiency is a critical risk factor for NAFLD, and suggest that supplementation with NAD(+) substrates may be a promising therapeutic strategy to prevent and treat NAFLD.

Targeting Nicotinamide Phosphoribosyltransferase as a Potential Therapeutic Strategy to Restore Adult Neurogenesis.

Adult neurogenesis is the process of generating new neurons throughout life in the olfactory bulb and hippocampus of most mammalian species, which is closely related to aging and disease. Nicotinamide phosphoribosyltransferase (NAMPT), also an adipokine known as visfatin, is the rate-limiting enzyme for mammalian nicotinamide adenine dinucleotide (NAD) salvage synthesis by generating nicotinamide mononucleotide (NMN) from nicotinamide. Recent findings from our laboratory and other laboratories have provided much evidence that NAMPT might serve as a therapeutic target to restore adult neurogenesis. NAMPT-mediated NAD biosynthesis in neural stem/progenitor cells is important for their proliferation, self-renewal, and formation of oligodendrocytes in vivo and in vitro. Therapeutic interventions by the administration of NMN, NAD, or recombinant NAMPT are effective for restoring adult neurogenesis in several neurological diseases. We summarize adult neurogenesis in aging, ischemic stroke, traumatic brain injury, and neurodegenerative disease and review the advances of targeting NAMPT in restoring neurogenesis. Specifically, we provide emphasis on the P7C3 family, a class of proneurogenic compounds that are potential NAMPT activators, which might shed light on future drug development in neurogenesis restoration.

Identification of benzothiophene amides as potent inhibitors of human nicotinamide phosphoribosyltransferase.

Nicotinamide phosphoribosyltransferase (Nampt) is an attractive therapeutic target for cancer. A Nampt inhibitor with novel benzothiophene scaffold was discovered by high throughput screening. Herein the structure-activity relationship of the benzothiophene Nampt inhibitor was investigated. Several new inhibitors demonstrated potent activity in both biochemical and cell-based assays. In particular, compound 16b showed good Nampt inhibitory activity (IC50=0.17 µM) and in vitro antitumor activity (IC50=3.9 µM, HepG2 cancer cell line). Further investigation indicated that compound 16b could efficiently induce cancer cell apoptosis. Our findings provided a good starting point for the discovery of novel antitumor agents.

Discovery of Novel Inhibitors and Fluorescent Probe Targeting NAMPT.

Nicotinamide phosphoribosyltransferase (NAMPT) is a promising antitumor target. Novel NAMPT inhibitors with diverse chemotypes are highly desirable for development of antitumor agents. Using high throughput screening system targeting NAMPT on a chemical library of 30000 small-molecules, we found a non-fluorescent compound F671-0003 and a fluorescent compound M049-0244 with excellent in vitro activity (IC50: 85 nM and 170 nM respectively) and anti-proliferative activity against HepG2 cells. These two compounds significantly depleted cellular NAD levels. Exogenous NMN rescued their anti-proliferative activity against HepG2 cells. Structure-activity relationship study proposed a binding mode for NAMPT inhibitor F671-0003 and highlighted the importance of hydrogen bonding, hydrophobic and π-π interactions in inhibitor binding. Imaging study provided the evidence that fluorescent compound M049-0244 (3 µM) significantly stained living HepG2 cells. Cellular fluorescence was further verified to be NAMPT dependent by using RNA interference and NAMPT over expression transgenic mice. Our findings provide novel antitumor lead compounds and a "first-in-class" fluorescent probe for imaging NAMPT.

Discovery and characterization of novel small-molecule inhibitors targeting nicotinamide phosphoribosyltransferase.

Nicotinamide phosphoribosyltransferase (NAMPT) is a promising anticancer target. Using high throughput screening system targeting NAMPT, we obtained a potent NAMPT inhibitor MS0 (China Patent ZL201110447488.9) with excellent in vitro activity (IC50 = 9.87 ± 1.15 nM) and anti-proliferative activity against multiple human cancer cell lines including stem-like cancer cells. Structure-activity relationship studies yielded several highly effective analogues. These inhibitors specifically bound NAMPT, rather than downstream NMNAT. We provided the first chemical case using cellular thermal shift assay to explain the difference between in vitro and cellular activity; MS7 showed best in vitro activity (IC50 = 0.93 ± 0.29 nM) but worst cellular activity due to poor target engagement in living cells. Site-directed mutagenesis studies identified important residues for NAMPT catalytic activity and inhibitor binding. The present findings contribute to deep understanding the action mode of NAMPT inhibitors and future development of NAMPT inhibitors as anticancer agents.