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Additional evidence indicates that the nitrate stored in the deep soil profile has an important role in regulating the global nitrogen (N) cycle. This study assessed the effects of land-use changes from croplands to intensive orchards (LUCO) on N surplus, nitrate accumulation in deep soil, and groundwater quality in the kiwifruit belt of the northern slope region of the Qinling Mountains, China. LUCO resulted in comparatively high N surplus in orchards (282 vs 1206 kg ha–1 yr–1, respectively). The average nitrate accumulation within the 0–10 m profiles of orchards was 7113 kg N ha–1, which was equal to approximately the total N surplus of 6 years of the orchards. The total nitrate stock within 0–10 m soil profiles of the kiwifruit belt was 266.5 Gg N, which was 3.5 times higher than the total annual N input. The nitrate concentrations of 97% of groundwater samples exceeded the WHO standard. The LUCO resulted in large nitrate storage in the vadose zone and caused serious contamination of groundwater. Our study highlights that nitrate accumulation in the vadose zone of an intensive land-use system is one of the main fates of surplus N and also a hotspot of nitrate accumulation.

Ni-Mo/γ-Al2O3 catalysts with different Ni loadings were prepared. They were characterized by X-ray diffraction (XRD), N2 adsorption, IR spectra of adsorbed pyridine (Py-IR), temperature-programmed ...

BACKGROUND: Abiraterone acetate, a CYP17 enzyme inhibitor, can block the synthesis of androgens in the adrenal gland, prostate, and testis. The purpose of this study was to investigate the efficacy and safety of abiraterone acetate in high-risk prostate cancer patients, including metastatic castration-resistant prostate cancer (mCRPC) and metastatic castration-sensitive prostate cancer (mCSPC). METHODS: A meta-analysis based on 6 randomized controlled trials (RCTs) was undertaken in compliance with the guidelines of systematic reviews and meta-analyses. Databases including PubMed, EMBASE, and Cochrane library were searched for relevant literature through to September 2019. RESULTS: The pooled analysis reported abiraterone acetate showed significant efficacy in high-risk prostate cancer patients, including overall survival (OS) [HR 0.66, 95% confidence interval (CI), 0.61–0.73, P

Background The BAP1 mutation is commonly found kidney renal clear cell carcinoma (KIRC) and a potential biomarker of individualized therapy. We evaluated the clinical significance of BAP1 mutation in the prognosis and treatment therapies for KIRC. Potential key pathways and related genes associated with these mechanisms were also identified in this investigation. Methods We identified the relevant data of patients BAP1 mutated on the cBioPortal and the compounds with significant selectivity to BAP1 mutations on the Genomics of Drug Sensitivity in Cancer (GDSC). And then, we identified the differences in mRNA expression levels of biological function annotation and pathways between mutated and wild type BAP1 patients by GSEA analysis. Furthermore, we screened the differentially expressed genes (DEGs) between BAP1 mutated and wild typed in KIRC patients and performed the GO and KEGG analysis. Finally, we conducted a protein-protein interaction (PPI) network to investigate the interaction between proteins encoded by candidate DEGs. Results Review of the TCGA data revealed 41 patients (10%) with KIRC displayed the BAP1 mutation. Further analysis led to the identification of 730 DEGs, while 617 genes were shown to be down-regulated, with 113 genes displaying upregulation. GO and KEGG pathway analysis indicated DEGs as enriched in metabolism, drug metabolism-cytochrome P450, and Drug-metabolizing enzymes. Subsequently, the top 10 hub genes, ranked by the degree in the PPI network were identified. Furthermore, our findings verify that the BAP1 mutation was associated with the deterioration of prognosis in patients with KIRC. Additionally, analysis of the GDSC database revealed that KIRC patients with BPP1 mutation are more prone to responding to Linsitinib. Conclusions Our investigation identified the main pathways and relevant genes related to the BAP1 mutation in KIRC, which can contribute to the development of targeted treatment strategies for enhanced prognostic predictions of KIRC.

Diabetic nephropathy (DN) is one of the late complications of diabetes, which seriously affects the lives of patients. Baicalin (BA) is a flavone glycoside that has been identified to improve renal function in patients with DN. The present study aimed to investigate the roles and mechanisms of BA in DN. For that purpose, podocytes were cultured for 48 h under conditions of high glucose (HG; 30 mM D-glucose) or normal glucose (NG; 5 mM D-glucose). Then, the cells were treated with different concentrations of BA (6.25, 12.5 and 25 µM) for 24 h. Cell viability and apoptosis were determined using an MTT assay and flow cytometry, respectively. Protein and mRNA expression levels were analyzed using western blotting and reverse transcription-quantitative PCR, respectively. BA treatment was identified to promote the viability of podocytes and suppress cell apoptosis in a dose-dependent manner. Compared with the results in the NG group, HG stimulation significantly decreased the viability of podocytes and increased the apoptotic rate, whereas BA treatment following HG stimulation increased the viability of podocytes and decreased the apoptotic rate. Moreover, the effect of BA was revealed to be associated with the sirtuin 1/NF-κB signaling pathway in DN. In conclusion, the results of the present study suggested that BA treatment may significantly decrease HG-induced podocyte apoptosis, which indicated that BA might be a promising agent for DN treatment.

Background Circular RNA (circRNA) remains a tumour-related factor in various biological cells and plays regulatory roles in gene expression. It is a type of non-coding RNA, whereas the function of human circRNA in hepatocellular carcinoma (HCC) is still not clear yet. Our investigation used the HCC cell line to uncover the biological function of hsa_circ_0056836 in the development and progression of hepatocellular carcinoma. Results The present study showed that hsa_circ_0056836 revealed high expressions in HCC cell lines and tissues compared with corresponding controls. Silencing of Hsa_circ_0056836 decreased cell migration, proliferation and invasion. Silencing of hsa_circ_0056836 inhibited the development of HCC in xenograft nude mice. Mechanistically, we found that hsa_circ_0056836 directly bound to miR-766-3p, thereby alleviating the targeted inhibition of Fos-related antigen 2 (FOSL2). The results of this study indicated that hsa_circ_0056836 is a novel oncogenic RNA of vast potential as a tumor biomarker. Conclusion In summary, the hsa_circ_0056836 / miR-766-3p / FOSL2 axis may serve as a promising strategy for HCC treatment. Method First, the expressions of hsa_circ_0056836 in HCC tissues and corresponding para-cancerous tissues as well as in HCC cell lines and normal hepatocytes THLE-3 were detected by RT-PCR. Subcellular localization of hsa_circ_0056836 was confirmed by FISH. To detect the association between hsa_circ_0056836 and miR-766-3p, AGO2-RIP and Luciferase reporter assay were adopted. Loss of function study was applied to assess the role of hsa_circ_0056836 in HCC and to determine tumorigenesis in nude mice.

Lactate has been observed to fuel TCA cycle and is associated with cancer progression in human lung cancer, the leading cause of cancer deaths worldwide, but the effect of lactate on lung cancer metabolism is rarely reported. In this study, disordered metabolism in non-small cell lung cancer was demonstrated by increased G6PD and SDHA protein levels via immunofluorescence, and up-regulated lactate dehydrogenase was found to be associated with poor prognosis. Then flow cytometry and Seahorse XFe analyzer were utilized to detect the effect of lactate on glycolysis and mitochondrial function in non-small cell lung cancer cells. The results show that in non-small cell lung cancer cells lactate attenuates glucose uptake and glycolysis while maintaining mitochondrial homeostasis as indicated by improved mitochondrial membrane potential. Further exploration found that mRNA levels of glycolytic enzymes (HK-1, PKM) and TCA cycle enzymes (SDHA, IDH3G) are respectively down-regulated and up-regulated by lactate, and increased histone lactylation was observed in promoters of HK-1 and IDH3G via chromatin immunoprecipitation assay. Taken together, the above results indicate that lactate modulates cellular metabolism at least in part through histone lactylation-mediated gene expression in non-small cell lung cancer.

Aiming at identifying the effects of the surface structure and composition for the Rh-Cu bimetallic catalysts on the catalytic performance in syngas conversion to C2 oxygenates, the mechanism of CO...

The Na,K-ATPase, consisting of a catalytic α-subunit and a regulatory β-subunit, is a ubiquitously expressed ion pump that carries out the transport of Na+ and K+ across the plasma membranes of most animal cells. In addition to its pump function, Na,K-ATPase serves as a signaling scaffold and a cell adhesion molecule. Of the three β-subunit isoforms, β1 is found in almost all tissues, while β2 expression is mostly restricted to brain and muscle. In cerebellar granule cells, the β2-subunit, also known as adhesion molecule on glia (AMOG), has been linked to neuron-astrocyte adhesion and granule cell migration, suggesting its role in cerebellar development. Nevertheless, little is known about molecular pathways that link the β2-subunit to its cellular functions. Using cerebellar granule precursor cells, we found that the β2-subunit, but not the β1-subunit, negatively regulates the expression of a key activator of the Hippo/YAP signaling pathway, Merlin/neurofibromin-2 (NF2). The knockdown of the β2-subunit resulted in increased Merlin/NF2 expression and affected downstream targets of Hippo signaling, i.e., increased YAP phosphorylation and decreased expression of N-Ras. Further, the β2-subunit knockdown altered the kinetics of epidermal growth factor receptor (EGFR) signaling in a Merlin-dependent mode and impaired EGF-induced reorganization of the actin cytoskeleton. Therefore, our studies for the first time provide a functional link between the Na,K-ATPase β2-subunit and Merlin/NF2 and suggest a role for the β2-subunit in regulating cytoskeletal dynamics and Hippo/YAP signaling during neuronal differentiation.

Background Liver injury is a serious threat for human health and life. Toll-like receptor 5 (TLR5) has reported to be a vital mediator in flagellin or tetrachloride (CCl4)-induced liver injury. However, the roles and etiology of TLR5 in hyperammonaemia (HA)-induced liver injury are poor defined. Methods HA rats were generated by intragastric administration using ammonium chloride solution. Liver status was assessed by haematoxylin and eosin (H&E) staining and measuring serum levels of liver injury markers. Immunohistochemistry (IHC) assay was used to visualize protein expression in tissues. Apoptotic index in tissues was determined by TUNEL assay. RT-qPCR assay was employed to test mRNA expression. Oxidative stress responses was assessed by detecting levels of reactive oxygen species (ROS) and related indicators. NF-κB activity was examined by TransAM NF-κB colorimetric kit. Results TLR5 was highly expressed in liver tissues of HA rats. TLR5 knockdown ameliorated HA-induced liver injury by inhibiting liver cell apoptosis. TLR5 depletion inhibited HA-induced pro-inflammatory cytokine expression in liver tissues, but had no effect on the infiltration of T and macrophage cells into liver tissues. TLR5 silencing impaired HA-induced oxidative stress responses in hepatocytes, but not in hepatic stellate cells (HSCs). TLR5 downregulation inhibited HA-induced activation on TLR5/NF-κB and TLR5/MAPK signaling pathways. Conclusion TLR5 silencing reduced HA-induced liver injury by inhibiting hepatocyte apoptosis, oxidative stress and inflammation responses via inactivating NF-κB and MAPK signals, deepening our understanding on the molecular mechanism of HA-induced liver injury and providing a potential therapeutic target for alleviating liver injury.

Neutrophils, classified as professional phagocytes, are crucial in killing bacteria and preventing inflammation. When studying the roles of neutrophils in the development of the septic peritonitis induced by E. coli, we noticed some of the larger cells existed among peritoneal lavage fluid cells (PLCs). Besides the large size, their nuclei are segmented and flat, and squeezed to the marginal zone of the inner membrane. The cells, therefore, were designated as E. coli induced larger neutrophils (e-Neus). Further studies showed that, the e-Neus were ly6G positive, indicating the e-Neus were a type of neutrophils. The enlarged cell size and marginal nucleus of the e-Neus were caused by engulfing abundant of E. coli, marking the active participation of the e-Neus in clearance of E. coli. Functionally, the e-Neus generated reactive oxygen species (ROS) and IL-10. Furthermore, the occurrence and accumulation of the e-Neus were closely correlated with the severity of septic peritonitis and mortality of the mice. Overall, the e-Neus presented here may enrich the understandings on neutrophil transitions in response to various insults, and could be used to evaluate the severity of septic peritonitis induced by E. coli.

In vivo positron emission tomography (PET) imaging is a key modality to evaluate disease status of brain tumors. In recent years, tremendous efforts have been made in developing PET imaging methods for pediatric brain tumors. Carbon-11 labelled tryptophan derivatives are feasible as PET imaging probes in brain tumor patients with activation of the kynurenine pathway, but the short half-life of carbon-11 limits its application. Using a transgenic mouse model for the sonic hedgehog (Shh) subgroup of medulloblastoma, here we evaluated the potential of the newly developed 1-(2-[18F]fluoroethyl)-L-tryptophan (1-L-[18F]FETrp) as a PET imaging probe for this common malignant pediatric brain tumor. 1-L-[18F]FETrp was synthesized on a PETCHEM automatic synthesizer with good chemical and radiochemical purities and enantiomeric excess values. Imaging was performed in tumor-bearing Smo/Smo medulloblastoma mice with constitutive actvation of the Smoothened (Smo) receptor using a PerkinElmer G4 PET-X-Ray scanner. Medulloblastoma showed significant and specific accumulation of 1-L-[18F]FETrp. 1-L-[18F]FETrp also showed significantly higher tumor uptake than its D-enantiomer, 1-D-[18F]FETrp. The uptake of 1-L-[18F]FETrp in the normal brain tissue was low, suggesting that 1-L-[18F]FETrp may prove a valuable PET imaging probe for the Shh subgroup of medulloblastoma and possibly other pediatric and adult brain tumors.

We report an in situ carbothermic reduction process to prepare osiers-sprout-like heteroatom-doped carbon nanofibers. The dosage of copper salts and a unique annealing process have a crucial effect on the development of this unique carbon structure. A systematic analysis is performed to elucidate the possible mechanism of synthesis of the carbon nanofibers decorated with carbon bubbles. As anodes for rechargeable lithium/sodium ion batteries, the heteroatom-doped nanofibers exhibit high reversible capacities and satisfactory long-term cycling stabilities. The osiers-sprout-like heteroatom-doped carbon nanofiber electrodes deliver an ultrastable cycling performance with reversible capacities of 480 and 160 mAh·g−1 for lithium-ion and sodium-ion batteries after 900 cycles at a current density of 800 mA·g−1, respectively.

The hydrodenitrogenation (HDN) with a low hydrogen consumption in the hydroprocessing of crude oils derived from carbon resources is still a challenge. Here, a molybdenum carbide (α-MoC1-x) catalyst with a high selectivity to aromatic compounds was reported, using the HDN of quinoline as a model reaction. This process was characterized by low hydrogen consumption. The prepared α-MoC1-x had a much larger specific surface area (107.6 m2•g−1) than β-Mo2C (6.8 m2•g−1). Under the catalysis of α-MoC1-x, the conversion and the denitrification rate of quinoline could both reach 99%, and the highest selectivity of the total aromatics reached 48.5% at 360 °C, which was 10.7% higher than that on β-Mo2C. The cleavage of C C bonds of side chain of Propylbenzene (PB) and Propylcyclohexane (PCH) occurred, producing several unexpected products with unusual high selectivity. A new possible reaction network of quinoline hydrodenitrogenation was drawn, and the reaction mechanism was discussed based on the experiments and DFT (density functional theory) calculations.

Land use change has greatly influenced groundwater quality worldwide. Identifying the effects of different intensive land uses on the groundwater quality is the first step in taking proper action to solve the problem. In this study, we compared the effects of different intensive land uses (region A, natural vegetation; region B, cereal fields; region C, kiwifruit orchards) in the Yujiahe catchment between 2015 and 2017 in Shaanxi, China, on the major ions and stable isotopes of nitrate (δ15N–NO3– and δ18O–NO3–). The NO3- groundwater concentrations increased from region A to region B and region C; NO3- concentrations in shallow groundwater were higher than those of deep groundwater in region C (55.3 vs. 28.9 mg/L, respectively). The NO3- concentrations in region A and region B did not exceed the WHO standard of 50 mg/L. However, 56.3% and 22.2% of the shallow and deep groundwater samples have NO3- concentrations exceeding the standard in region C, respectively. The average electrical conductivity (EC) values of springs in region A and shallow groundwater in regions B and C were 438, 525, and 753 µs/cm, respectively. Concentrations of Ca2+, Mg2+, Na+, Cl-, and HCO3- ions and nitrogen isotope values increased from region A to region C, indicating that intensive land use change has modified groundwater hydrochemical composition, and deteriorated groundwater quality. This study has highlighted the significant effect of intensive land use of orchards at the small catchment scale on the groundwater quality.

We report an electron-beam lithography process to directly fabricate graphene@copper composite patterns without involving metal deposition, lift-off and etching processes using copper naphthenate as a high-resolution negative-tone resist. As a commonly used industrial painting product, copper naphthenate is extremely cheap with a long shelf time but demonstrates an unexpected patterning resolution better than 10 nm. With appropriate annealing under a hydrogen atmosphere, the produced graphene@copper composite patterns show high conductivity of ∼400 S cm−1. X-ray diffraction, conformal Raman spectroscopy and X-ray photoelectron spectroscopy were used to analyze the chemical composition of the final patterns. With the properties of high resolution and high conductivity, the patterned graphene@copper composites could be used as conductive pads and interconnects for graphene electronic devices with ohmic contacts. Compared to common fabrication processes involving metal evaporation and lift-off steps, this pattern-transfer-free fabrication process using copper naphthenate resist is direct and simple but allows comparable device performance in practical device applications.

Cell-based high-throughput drug screening (HTS) is a common starting point for the drug discovery and development process. Currently, there is a push to combine complex cell culture systems with HTS to provide more clinically applicable results. However, there are mechanistic requirements inherent to HTS as well as material limitations that make this integration challenging. Here, we used the peptide-based shear-thinning hydrogel MAX8 tagged with the RGDS sequence to create a synthetic extracellular scaffold to culture cells in three dimensions and showed a preliminary implementation of the scaffold within an automated HTS setup using a pilot drug screen targeting medulloblastoma, a pediatric brain cancer. A total of 2202 compounds were screened in the 384-well format against cells encapsulated in the hydrogel as well as cells growing on traditional two-dimensional (2D) plastic. Eighty-two compounds passed the first round of screening at a single point of concentration. Sixteen-point dose-response was done on those 82 compounds, of which 17 compounds were validated. Three-dimensional (3D) cell-based HTS could be a powerful screening tool that allows researchers to finely tune the cell microenvironment, getting more clinically applicable data as a result. Here, we have shown the successful integration of a peptide-based hydrogel into the high-throughput format.

Lymphocyte activation gene-3 (LAG3) is a transmembrane protein expressed on activated T cells and delivers inhibitory signals to render the T cells unable to effectively help B cells to produce antibodies to microbes and vaccines. Presumably, antagonizing LAG3 could enhance the antibody responses to vaccines, and LAG3 antagonists could facilitate vaccines to induce vigorous antibody responses. In this study, we designed a LAG3-interfering antisense oligonucleotide, designated as LIO-1. The LIO-1 is complementary to an identical region shared in human and mouse LAG3 mRNA. We demonstrated that LIO-1 induced the degradation of LAG3 mRNA in immune cells, decreased the LAG3 expression on CD4+ T cells, maintained the prolonged proliferation and promoted the activation of antigen-specific CD4+ T cells, and increased the production of IFN-γ, IL-2, and IL-6 in the antigen re-stimulated immune cells. In addition, we found that LIO-1 enhanced the antibody responses induced by ISA35-formulated recombinant antigen vaccine or ISA35-formulated inactivated influenza virus vaccines in mice. Thus, the LIO-1, a nucleic acid LAG3 antagonist, could facilitate vaccines to induce vigorous antibody responses and has the possibility to be used as a novel adjuvant.

Objective Homocysteine plays critical roles in cellular redox homeostasis, and hyperhomocysteinemia has been associated with multiple diseases, including neurological disorders involving reactive oxygen species-inducing and pro-inflammatory effects of homocysteine that are related to mitochondria. This study investigated the role of homocysteine in regulating mitochondria of neuron cell lines. Methods Neuron cells were pre-treated with homocysteine, and then flow cytometry was used to detect reactive oxygen species production and mitochondrial membrane potential, while Seahorse XFp Mito stress assay was used to comprehensively analyze mitochondrial function. Results The experimental results showed that high-concentration homocysteine diminished carbonyl cyanide-4 (trifluoromethoxy) phenylhydrazone-stimulated oxygen consumption rate and mitochondrial spare respiration capacity in a time- and concentration-dependent manner, and homocysteine also reduced reactive oxygen species in cultured neuron cell lines while no changes in mitochondrial membrane potential were observed. Conclusion These results indicate that homocysteine diminished mitochondrial respiration function in neuron cell lines mediated by its reactive oxygen species-reducing effects, which may underlie the association between hyperhomocysteinemia and human diseases.

Summary Objectives CD4 + Foxp3 + regulatory T-cells (Treg) are known to accumulate under certain pathological conditions. This study was conducted to evaluate the characteristics of and dynamic changes in Treg cells in chronic hepatitis C (CHC) patients during antiviral therapy. Methods One hundred and forty-five subjects were enrolled in this study, including 105 CHC patients and 40 healthy donors. The phenotypes and functions of Treg cells were analyzed by flow cytometry. Results A significant elevation in Treg cells was observed in the peripheral blood of CHC patients compared with healthy donors. Interestingly, compared with non-suppressive Treg (non-Treg) and resting Treg (rTreg) cells, activated Treg (aTreg) cells expressed higher levels of ectonucleotidase, CD39, and CD73. After treatment with interferon alpha (IFN-α) and ribavirin (RBV) in vitro, the frequencies of total Treg cells and aTreg cells in peripheral blood mononuclear cells (PBMC), as well as the levels of transforming growth factor beta (TGF-β) secreted by aTreg and non-Treg cells, were significantly decreased. Importantly, it was found that levels of aTreg cells in patients with a sustained virological response (SVR) were lower than in relapsed patients, suggesting that a high frequency of aTreg cells might be associated with a poor clinical outcome in HCV infection. Conclusion These results demonstrate a decreasing trend in aTreg cells, which express higher levels of CD39, CD73, and TGF-β, in SVR patients during antiviral therapy.

In vivo positron emission tomography (PET) imaging is a key modality to evaluate disease status of brain tumors. In recent years, tremendous efforts have been made in developing PET imaging methods for pediatric brain tumors. Carbon-11 labelled tryptophan derivatives are feasible as PET imaging probes in brain tumor patients with activation of the kynurenine pathway, but the short half-life of carbon-11 limits its application. Using a transgenic mouse model for the sonic hedgehog (Shh) subgroup of medulloblastoma, here we evaluated the potential of the newly developed 1-(2-[18F]fluoroethyl)-L-tryptophan (1-L-[18F]FETrp) as a PET imaging probe for this common malignant pediatric brain tumor. 1-L-[18F]FETrp was synthesized on a PETCHEM automatic synthesizer with good chemical and radiochemical purities and enantiomeric excess values. Imaging was performed in tumor-bearing Smo/Smo medulloblastoma mice using a Perkin-Elmer G4 PET-X-Ray scanner. Medulloblastoma tumors showed significant and specific accumulation of 1-L-[18F]FETrp. 1-L-[18F]FETrp also showed significantly higher tumor uptake than its D-enantiomer 1-D-[18F]FETrp. The uptake of 1-L-[18F]FETrp in normal brain tissue was low, suggesting that 1-L-[18F]FETrp may prove a valuable PET imaging probe for the Shh subgroup of medulloblastoma and possibly other pediatric and adult brain tumors. Citation Format: Xuyi Yue, Yangchun Xin, Hua Li, Zhiqin Li, Hancheng Cai, Sigrid A. Langhans. Tumor-specific PET imaging with an 18F-labeled tryptophan analogue in a transgenic medulloblastoma mouse model [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1652.

Pd-decorated Cu bimetallic catalysts experimentally exhibited better catalytic performance toward hydrogenation reaction than the single Pd or Cu catalyst. This study is expected to identify the role of the Pd ensemble in determining the activity and selectivity, thus, HCOOH dissociation over the Pd-decorated Cu catalysts with different surface Pd distribution is fully examined by employing density functional theory calculations, including Pd1Cu8, Pd3Cu6, Pd6Cu3 and Pd9Cu0 catalysts, which are compared to the single Pd and Cu catalysts. The results found the Pd ensemble on the Pd6Cu3 and Pd9Cu0 surfaces with the Pd/Cu ratio of 6/3 and 9/0 exhibit higher selectivity and activity toward CO2 formation via the COOH intermediate, especially, Pd6Cu3 is superior to the single Pd; whereas the isolated Pd atom on the Pd1Cu8 and Pd3Cu6 surfaces with the Pd/Cu ratio of 1/8 and 3/6 dominantly produce CO via the COOH intermediate. Further, the structural and electronic properties reveal the role of the Pd ensemble in determining the catalytic performance of HCOOH dissociation. Our results provide a valuable clue and evaluation method in designing low-cost catalyst with the noble metal-decorated the non-noble metal catalysts, which can exhibit better catalytic performance by forming the surface ensemble of the noble metal.

Aiming at identifying the effects of the support types, properties and the metal-support interaction of the supported catalysts on C2H4 selectivity and its formation activity for C2H2 semi-hydrogenation, the corresponding mechanism over the supported Pd and Cu catalysts with different supports are fully studied based on DFT calculations. This work indicates that the support types and properties change the selectivity of C2H4 and its formation activity, for the supported Pd catalysts, the oxygen-vacancy anatase and rutile TiO2 supports present much better selectivity of C2H4 and its formation activity than the pure Pd catalyst does; especially, the anatase exhibits better catalytic performance than the rutile, in which the oxygen-vacancy show the crucial function. For the supported Cu catalysts, γ-Al2O3 is unable to enhance C2H4 selectivity compared to the pure Cu catalyst, whereas MgO support improves C2H4 selectivity but reduces its formation activity. Further, the metal-support interaction of the supported Pd catalysts are much stronger than that of the supported Cu catalyst, which results in better activity and selectivity of C2H4 over the supported Pd catalysts. This study can give out a valuable clue for the preparation of the supported Pd or Cu catalysts with better performance in C2H2 semi-hydrogenation.

Based on two promising p-CPhH4IDC and o-CPhH4IDC ligands, one 2D coordination polymer, [Ca(p-CPhH2IDC)(H2O)] n (p-CPhH4IDC = 2-(4-carboxylphenyl)-1H-imidazole-4,5-dicarboxylic acid) (I) and one novel dimeric complex, [Cd2(o-CPhH2IDC)2(H2O)6] · 4H2O (o-CPhH4IDC = 2-(2-carboxylphenyl)-1H-imidazole-4,5-dicarboxylic acid) (II) have been hydrothermally synthesized and structurally characterized by elemental analyses, IR spectroscopy, and single crystal X-ray diffraction (CIF files CCDC nos. 929826 (I), 959841 (II)). Polymer I exhibits a graceful 2D grid sheet structure. Polymer II is a binuclear complex in which two Cd2+ ions are bridged by two carboxyates from two o-CPhH2IDC2– ligands. Four and two types of coordination environments around the Ca and Cd atoms, respectively can be observed. Furthermore, the solid-state photoluminescence and thermal properties of the two complexes have been investigated.

Human leukocyte antigen (HLA) alleles are associated with both the progression of chronic hepatitis C (CHC) and the sustained virological response (SVR) to antiviral therapy. HLA-A*02 is the most common HLA allele in people of European/Caucasian descent and the Chinese and Japanese population. Therefore, we investigated whether HLA-A*02 expression is associated with disease outcome in Chinese CHC patients. Three hundred thirty-one treatment-naive CHC patients were recruited in this study. The expression of HLA-A*02 was tested by FACS and LABType SSO assays. All patients were treated weekly with pegylated interferon plus ribavirin (PEG-IFN/RBV) according to a standard protocol. Virological response was assessed by TaqMan assay at the 4th, 12th, 24th, and 48th week of therapy, and again at the 24th week post-therapy. By the end of the study, 293 CHC patients, including 144 HLA-A*02-positive patients and 149 HLA-A*02-negative patients, were evaluable for analysis. There were no statistical differences in clinicopathological parameters between HLA-A*02-positive and negative patients before antiviral therapy (P > 0.05). The HLA-A*02-positive patients had a higher rapid virological response (RVR, 74.3 % versus 62.4 %, P = 0.03) and SVR (78.5 % versus 64.4 %, P = 0.01) and a lower relapse rate (4.2 % versus 11.9 %, P = 0.03) than HLA-A*02-negative patients. Multivariable logistic regression analysis showed that HLA-A*02 expression, liver fibrosis stages

Automated cell-based high-throughput screening (HTS) is a powerful tool in drug discovery, and it is increasingly being recognized that three-dimensional (3D) models, which more closely mimic in vivo-like conditions, are desirable screening platforms. One limitation hampering the development of 3D HTS is the lack of suitable 3D culture scaffolds that can readily be incorporated into existing HTS infrastructure. We now show that β-hairpin peptide hydrogels can serve as a 3D cell culture platform that is compatible with HTS. MAX8 β-hairpin peptides can physically assemble into a hydrogel with defined porosity, permeability and mechanical stability with encapsulated cells. Most importantly, the hydrogels can then be injected under shear-flow and immediately reheal into a hydrogel with the same properties exhibited prior to injection. The post-injection hydrogels are cell culture compatible at physiological conditions. Using standard HTS equipment and medulloblastoma pediatric brain tumor cells as a model system, we show that automatic distribution of cell-peptide mixtures into 384-well assay plates results in evenly dispensed, viable MAX8-cell constructs suitable for commercially available cell viability assays. Since MAX8 peptides can be functionalized to mimic the microenvironment of cells from a variety of origins, MAX8 peptide gels should have broad applicability for 3D HTS drug discovery.

Plumbagin inhibits the growth, metastasis, and invasion of prostate cancer (PCa). However, its lower bioavailability limits biopharmaceutical properties due to insolubility in water. Prostate-specific membrane antigen (PSMA) aptamer-targeted nanoparticles (NPs) significantly enhanced cytotoxicity in prostate epithelial cells. This study aimed to investigate the effects of plumbagin-loaded prostate-specific membrane antigen (PSMA) aptamer-targeted poly d,l-lactic-co-glycolic acid-b-polyethylene glycol (PLGA-PEG) nanoparticles (NPs) on prostate cancer (PCa) in vitro. PLGA–PEG with a terminal carboxylic acid group (PLGA-PEG-COOH) was synthesized, and plumbagin was loaded on PLGA-PEG-COOH NPs using the nanoprecipitation method and characterized by field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), and laser light scattering. The uptake and distribution of plumbagin-NPs in human PCa LNCaP cells were investigated by fluorescent labeling. Subsequently, PSMA antibody-targeted PLGA-PEG-COOH NPs (targeted NPs) were prepared by covalent binding and characterized by x-ray photoelectron spectroscopy. Furthermore, the anticancer activity of plumbagin-loaded, targeted NPs was compared with that of nontargeted NPs in LNCaP cells in vitro. Plumbagin-NPs (diameter of 189.4 ± 30.6 nm and zeta potential of −17.1 ± 3.7 mV) were optimized based on theoretical drug loading of 5% and a ratio of water:acetone of 3:1. During the first 2 hours, the cumulative release rate of the drug was 66.4 ± 8.56%. Moreover, plumbagin-targeted NPs with nitrogen atoms were prepared. The uptake rate was 90% at 0.5 hours for targeted and nontargeted NPs. The IC50 of targeted NPs and nontargeted NPs was 32.59 ± 8.03 μM and 39.02 ± 7.64 μM, respectively. Plumbagin-loaded PSMA aptamer-targeted NPs can be used in targeted chemotherapy against PCa.

This study aimed to explore the effect of kushenin combined with adefovir dipivoxil on the load of hepatitis B virus DNA (HBV-DNA) in serum, in immune functions and in liver functions of patients with chronic hepatitis B. A sample of 80 patients with chronic hepatitis B was selected who were admitted to Weifang People's Hospital for treatment between January, 2013 and December, 2015. They were divided into the observation group (n=40) and the control group (n=40). The patients in both groups received adefovir dipivoxil, while those in the observation group additionally received the kushenin. Variations in HBV-DNA load and transforming growth factor-β1 (TGF-β1) in the two groups were detected before intervention, at 1 month, 3 months and 6 months after intervention. In addition, after intervention, we also observed the changes in CD4+, CD8+ and CD4+/CD8+, as well as the levels of immune globulin. Furthermore, in these two groups, we detected the changes in endotoxin in serum before and after intervention, the liver function after intervention, and the variations of hyaluronic acid (HA) and type III procollagen (PCIII) before and after intervention which were used to serve as the indicators for hepatic fibrosis. Results showed that at one month, 3 months and 6 months after intervention, HBV-DNA load and the level of TGF-β1 in the observation group were lower than those in the control group (P

The interaction of human serum albumin (HSA) with hexythiazox (HEX) and the alterations of protein secondary structure in the presence of HEX were investigated by molecular docking, UV-vis absorption spectrometry, synchronous fluorescence spectrometry and three-dimensional fluorescence spectroscopy. Forecasting molecular docking results revealed that HEX could bind on site Ⅰ and site Ⅱ where it was easier to combine in HSA. The experiment results indicated that HEX had a strong ability to quench the intrinsic fluorescence of HSA through static quenching procedure. At the same time, HEX altered HSA surrounding microenvironment and led to change in the peptide chain structure of the protein. Binding affinity ( K A) and the amounts of binding sites ( n ) between HEX and HSA at 298 and 291 K were estimated as 7.35 × 103 mol/L, 0.82 and 1.02 × 104 mol/L, 0.86, respectively, which confirmed that HEX could only bind on site Ⅱ. The binding power between HEX and HSA involved mainly hydrogen bonds, van der Waals and hydrophobic forces, and an apparent distance between the Trp214 and HEX was 3.01 nm. The various informations of these studies help to understand toxicity of pesticide to humans and their bioaccumulative potential at the molecular level.

Background & Aims Few patients from developing countries can afford brand name direct-acting antiviral agents for treating hepatitis C virus (HCV) infection, and controversy regarding the bioequivalence of generics exists. This study aimed to observe the safety and efficacy of 8 or 12weeks of generic ledipasvir-sofosbuvir with or without ribavirin for Chinese genotype 1b HCV-infected patients. Methods In this open-labelled observational study, 63 cirrhotic (group 1) and 65 non-cirrhotic (group 2) patients were administered generic ledipasvir-sofosbuvir plus 1000–1200mg of ribavirin daily for 12 and 8weeks, respectively; and 64 non-cirrhotic patients (group 3) received ledipasvir-sofosbuvir for 8weeks. The primary efficacy endpoint was undetectable HCV RNA at week 12 (SVR12) after cessation of therapy. Safety and pharmacokinetic data were collected. Results One hundred and eighty-seven patients completed treatment, and the latest undetectable HCV RNA was observed in three patients with cirrhosis at week 5 during treatment. Intention-to-treat analysis revealed 96.8% (61/63), 96.9% (63/65), and 96.9% (62/64) of SVR12 rates in groups 1, 2, and 3, respectively. One patient in group 3 relapsed at post-treatment week 4. The regimens were generally well-tolerated. The most common adverse events were fatigue (17.8%), diarrhea (10.9%), and headache (9.9%). Four patients discontinued therapy due to diarrhea and vomiting. One patient from group 2 discontinued treatment on day 29 because of drug-unaffordability; fortunately, she achieved SVR12. Conclusion This study demonstrated that 8 or 12weeks of generic ledipasvir-sofosbuvir with or without ribavirin are safe and effective for patients with genotype 1b HCV infection. Lay summary The price of Harvoni® has led to restrictions and access limitations in many developing and even developed countries with limited healthcare budgets. Gilead approved generic ledipasvir-sofosbuvir costs far less than Harvoni® and presents a similar cure rate for patients with chronic hepatitis C.

Single-crystal silicon nanostructures have attracted much attention in recent years due in part to their unique optical properties. In this work, we demonstrate direct fabrication of single-crystal silicon nanotubes with sub-10 nm walls which show low reflectivity. The fabrication was based on a cryogenic inductively coupled plasma reactive ion etching process using high-resolution hydrogen silsesquioxane nanostructures as the hard mask. Two main etching parameters including substrate low-frequency power and SF6/O2 flow rate ratio were investigated to determine the etching mechanism in the process. With optimized etching parameters, high-aspect-ratio silicon nanotubes with smooth and vertical sub-10 nm walls were fabricated. Compared to commonly-used antireflection silicon nanopillars with the same feature size, the densely packed silicon nanotubes possessed a lower reflectivity, implying possible potential applications of silicon nanotubes in photovoltaics.

Na,K-ATPase is an ion pump that creates an electrochemical gradient across the plasma membrane. In addition, Na,K-ATPase functions as a receptor and a signaling scaffold and its β-subunit has cell adhesion function. Many of the signaling pathways modulated by Na,K-ATPase have been linked to cell growth, apoptosis, cell adhesion, and motility. Changes in Na,K-ATPase function and expression have been reported in various cancers, even early during tumor development. Epithelial–mesenchymal transition (EMT) in which epithelial cells undergo a shift from a well-differentiated polarized epithelial phenotype to a fibroblastic, mesenchymal phenotype is one of the earliest steps in tumor progression. EMT can be induced by growth factors that activate signaling pathways to trigger an intricate network of transcriptional regulators. Interestingly, some of the transcription factors induced during EMT are known regulators of Na,K-ATPase expression. Here we summarize some of the best characterized EMT-inducing pathways, the transcription factors modulated by these signaling pathways and discuss how they may affect Na,K-ATPase subunit expression.

We studied the interaction of 3,3',3'',3'''-ethylenetetrakis-4-hydroxycoumarin (EHC) with bovine serum albumin (BSA) in acetate buffer and phosphate buffer with different pH values by UV-vis absorption spectrometry and fluorescence spectrometry respectively. It was found that the pH values of the buffer solutions had an effect on the interaction process. In acetate buffer of pH 4.70, the carbonyl groups in EHC bound to the amino groups in BSA by means of hydrogen bond and van der Waals force, which made the extent of peptide chain in BSA changed. By contrast, in phosphate buffer of pH 7.40, hydrophobic force played a major role in the interaction between EHC and BSA, while the hydrogen bond and van der Waals force were also involved in the interaction. The results of spectrometry indicated that BSA could enhance the fluorescence intensity of EHC by forming a 1:1 EHC-BSA fluorescent complex through static mechanism at pH 4.70 and 7.40 respectively. Furthermore, EHC bound on site 1 in BSA.

Single crystalline silicon nanotubes along the [001] direction with different outer diameters and wall thicknesses have been successfully prepared via a high-fidelity nanofabrication process by combining electron-beam lithography and reactive-ion etching methods. A higher specific surface-to-volume ratio compared with other solid one-dimensional nanomaterials has been achieved. In situ compression results revealed a strong saddle-shaped surface-to-volume ratio effect on the Young's modulus, and the Young's modulus increases to a peak value at a surface-to-volume ratio of ∼0.04 nm−1 and then decreases at a higher surface-to-volume ratio. A single core with a double shell model is proposed to interpret this unique saddle-shaped surface-to-volume ratio effect, which may play a guiding role in designing the nanoscale objects for device applications.

Medulloblastoma is the most common malignant brain tumor of childhood. Despite major advances, long-term survival is hindered by relapse and leptomeningeal spread, necessitating the development of novel diagnostic and therapeutic approaches. Abnormal tryptophan metabolism, via the immunomodulatory indoleamine-2,3-dioxygenase (IDO)/ tryptophan-2,3 dioxygenase (TDO)-mediated kynurenine pathway (KP), has been demonstrated in tumors, and is emerging as a valid target for immunotherapy as well as non-invasive tumor imaging. Previously, a positron emission tomography (PET) tracer, α-[(11)C] methyl-L-tryptophan ([(11)C] AMT), has been successfully used to evaluate the increased tryptophan metabolism and uptake through KP in patients with glioma. Nevertheless, the short half-life of the carbon-11 isotope has limited the broad applications of [(11)C] AMT in clinical research and diagnostics. In this study, using a novel PET tracer, 1-(2-[(18)F]fluoroethyl)-L-tryptophan (L-1-[(18)F]FETrp) with similar pathophysiological and metabolic properties as [(11)C] AMT, we assessed the tryptophan metabolism in a transgenic mouse model of the Sonic hedgehog (Shh) subgroup of medulloblastoma. In Smo-Smo mice, preliminary PET imaging data showed increased accumulation of L-1-[(18)F]FETrp in tumors as compared to normal brain tissue. Immunofluorescence and molecular analysis of tumor tissues obtained from Smo-Smo mice indicated increased expression of TDO2, but not IDO1. Both TDO2 and IDO1 are tissue-specific first step and rate-limiting enzymes of the KP of tryptophan metabolism. Thus, our preclinical studies in Smo-Smo mice indicate that L-1-[(18)F]FETrp may be a suitable tracer for PET imaging of medulloblastoma tumors and could provide valuable information for noninvasive assessment of immunotherapy response and move towards targeted therapy for medulloblastoma in the future.

The aim of this study was to determine whether combined utilization of untimed single urine monocyte chemoattractant protein 1 (uMCP-1) and tumor necrosis factor (TNF)-like weak inducer of apoptosis (uTWEAK) could serve as a screening test for proteinuria in patients with lupus nephritis (LN).A case-control study that contained 39 biopsy-proven LN patients, 20 non-LN systemic lupus erythematosus (SLE) patients, and 10 healthy controls (HCs) were carried out. Correlations between uMCP-1, uTWEAK, and traditional clinical markers were analyzed by Spearman correlation test. Diagnostic values of uMCP-1, uTWEAK, and urine albumin/creatinine ratio (uACR) in the assessment of proteinuria were investigated by receiver operating characteristic (ROC) curves.Biopsy-proven LN patients showed higher levels of uMCP-1 and uTWEAK than non-LN patients. uMCP-1 and uTWEAK were elevated in renal active patients (rSLEDAI ≥4). Both uMCP-1 and uTWEAK showed significant correlation with patients' rSLEDAI, 24-hour urine proteinuria (24hr UP), and anti-double-stranded DNA (anti-dsDNA) antibodies. No correlations of these 2 biomarkers between cystatin C (Cys-C), creatinine (Cr), and blood urea nitrogen (BUN) were observed. An algorithm combining the moderate sensitivity of uMCP-1 and high specificity of uTWEAK displayed great specificity and sensitivity for proteinuria screening.Both uMCP-1 and uTWEAK were positively correlated with the impairments of LN, and the combined utility of untimed single uMCP-1 and uTWEAK might be used as potential predictors for proteinuria in LN.

Silicon nanostructures have been attracting increasing attention as nanoscale Mie scatters for various applications due to the subwavelength light concentration capability endowed by its high refractive index and the fabrication compatibility with the chip manufacturing processes. In this work, we investigate the polarization-dependent scattering properties of lithographic single-crystalline silicon nanocylindroids at the visible range. Both simulated and experimental studies were carried out to reveal the electric and magnetic resonance modes that occur in the silicon nanocylindroids. Systematic control experiments were conducted to demonstrate the polarization and size dependence of the resonance-induced scattering peaks. The unique anisotropic optical property of lithographically fabricated Si nanostructures at the single particle resolution provides an extra freedom to design silicon-based optical elements at the visible range for enhanced light-matter interactions.

Elevated metallic nanostructures with nanogaps (

Leptin controls body weight by activating its long form receptor (LEPRb). LEPRb binds to Janus kinase 2 (JAK2), a cytoplasmic tyrosine kinase that mediates leptin signaling. We previously reported that genetic deletion of SH2B1 (previously known as SH2-B), a JAK2-binding protein, results in severe leptin-resistant and obese phenotypes, indicating that SH2B1 is a key endogenous positive regulator of leptin sensitivity. Here we show that SH2B1 regulates leptin signaling by multiple mechanisms. In the absence of leptin, SH2B1 constitutively bound, via its non-SH2 domain region(s), to non-tyrosyl-phosphorylated JAK2, and inhibited JAK2. Leptin stimulated JAK2 phosphorylation on Tyr813, which subsequently bound to the SH2 domain of SH2B1. Binding of the SH2 domain of SH2B1 to phospho-Tyr813 in JAK2 enhanced leptin induction of JAK2 activity. JAK2 was required for leptin-stimulated phosphorylation of insulin receptor substrate 1 (IRS1), an upstream activator of the phosphatidylinositol 3-kinase pathway. Overexpression of SH2B1 enhanced both JAK2- and JAK2(Y813F)-mediated tyrosine phosphorylation of IRS1 in response to leptin, even though SH2B1 did not enhance JAK2(Y813F) activation. Leptin promoted the interaction of SH2B1 with IRS1. These data suggest that constitutive SH2B1-JAK2 interaction, mediated by the non-SH2 domain region(s) of SH2B1 and the non-Tyr813 region(s) in JAK2, increases the local concentration of SH2B1 close to JAK2 and inhibits JAK2 activity. Leptin-stimulated SH2B1-JAK2 interaction, mediated by the SH2 domain of SH2B1 and phospho-Tyr813 in JAK2, promotes JAK2 activation, thus globally enhancing leptin signaling. SH2B1-IRS1 interaction facilitates IRS1 phosphorylation by recruiting IRS1 to JAK2 and/or by protecting IRS1 from dephosphorylation, thus specifically enhancing leptin stimulation of the phosphatidylinositol 3-kinase pathway.

Casper/c-FLIP is a caspase-8-related molecule critically involved in regulation of death receptor-induced apoptosis. It has been shown that Casper can either promote or antagonize apoptosis and can activate the transcription factor NF-kappaB. The exact functions of Casper are controversial. To further understand how Casper signals, we searched Casper-interacting proteins by yeast two-hybrid screening. This effort identified NF-kappaB1 (p105), an atypical IkappaB molecule and the precursor of NF-kappaB subunit p50. Co-immunoprecipitation experiments indicated that Casper interacted with p105 in 293 cells and this interaction was mediated through the C-terminal IkappaB-like domain (IkappaBgamma). Overexpression of p105 and IkappaBgamma inhibited Casper-induced NF-kappaB activation and potentiated Casper-induced apoptosis. Furthermore, Casper and its C-terminal caspase-like domain inhibited p105 processing into p50. Our findings suggest that p105 is involved in Casper-mediated regulation of apoptosis and NF-kappaB activation.

The affinity between two plant-growth regulators (PGRs) and human serum albumin (HSA) was investigated by molecular modeling techniques and spectroscopic methods. The results of molecular modeling simulations revealed that paclobutrazol (PAC) could bind on both site I and site II in HSA where the interaction was easier, while uniconazole (UNI) could not bind with HSA. Furthermore, the results of fluorescence spectroscopy, three-dimensional (3D) fluorescence spectroscopy and circular dichroism (CD) spectroscopy suggested that PAC had a strong ability to quench the intrinsic fluorescence of HSA. The binding affinity ( K b ) and the amounts of binding sites ( n ) between PAC and HSA at 291 K were estimated as 2.37 × 10 5 mol L −1 and 1, respectively, which confirm that PAC mainly binds on site II of HSA. An apparent distance between the Trp214 and PAC was 4.41 nm. Additionally, the binding of PAC induced the conformational changes of disulfide bridges of HSA with the decrease of α -helix content. These studies provide more information on the potential toxicological effects and environmental risk assessment of PGRs.

We report a bilayer-like electron-beam lithographic process to obtain three-dimensional (3D) nanostructures by using only a single hydrogen silsesquioxane (HSQ) resist layer. The process utilizes the short penetration depth of low-energy (1.5 keV) electron irradiation to first obtain a partially cross-linked HSQ top layer and then uses a high-voltage electron beam (30 keV) to obtain self-aligned undercut (e.g. mushroom-shaped) and freestanding HSQ nanostructures. Based on the well-defined 3D resist patterns, 3D metallic nanostructures were directly fabricated with high fidelity by just depositing a metallic layer. As an example, Ag-coated mushroom-shaped nanostructures were fabricated, which showed lower plasmon resonance damping compared to their planar counterparts. In addition, the undercut 3D nanostructures also enable more reliable lift-off in comparison with the planar nanostructures, with which high-quality silver nanohole arrays were fabricated which show distinct and extraordinary optical transmission in the visible range.

The direct electrochemistry of hemoglobin (Hb) and application in its interaction with 3,4'-bis-(4-hydro-3-xycoumarin)-2,5-hexanediol (HCH) based on the Hb immobilized in chitosan-room temperature ionic liquid film were investigated by means of cyclic voltammetry, differential pulse voltammetry and amperometry. The binding ratio m and binding constant between HCH and Hb were estimated as 2 and 3.46 M(-1), respectively. The amperometric response showed a linear dependence on the concentration of HCH with the detection limit of 0.06 μM. In addition, the amperometry was a novel method in the field of binding studies and might be taken into account for future binding studies. At last a sensitive and convenient electrochemical method was proposed for the determination of HCH.

Leptin controls body weight by activating the long form of the leptin receptor (LEPRb). Janus kinase 2 (JAK2) is associated with LEPRb and autophosphorylates in response to leptin. JAK2 also phosphorylates LEPRb, STAT3, and multiple other downstream molecules. Surprisingly, here we show that JAK2 is not required for leptin stimulation of STAT3 phosphorylation. Leptin time- and dose-dependently stimulated tyrosine phosphorylation of STAT3 in both human and mouse JAK2-null cells. Leptin also increased the viability of JAK2-null cells. Overexpression of c-Src or Fyn, two Src family members, promoted STAT3 phosphorylation, whereas inhibition of the endogenous Src family members by either pharmacological inhibitors or dominant negative Src(K298M) decreased the ability of leptin to stimulate the phosphorylation of STAT3 and ERK1/2. Leptin also stimulated tyrosine phosphorylation of kinase-inactive JAK2(K882E) in JAK2-null cells. Overexpression of JAK2(K882E) enhanced the ability of leptin to stimulate STAT3 phosphorylation in JAK2-null cells. Tyr1138 in LEPRb was required for leptin-stimulated phosphorylation of STAT3 but not JAK2(K882E). These data suggest that leptin stimulates non-JAK2 tyrosine kinase(s), including the Src family members, which phosphorylate JAK2, STAT3, and other molecules downstream of LEPRb. JAK2 mediates leptin signaling by both phosphorylating its substrates and forming a signaling complex as a scaffolding/adaptor protein. The non-JAK2 kinase(s) and JAK2 may act coordinately and synergistically to mediate leptin response.

Pleckstrin homology (PH) domains are phosphoinositide (PI)-binding modules that target proteins to membrane surfaces. Here we define a family of PH domain proteins, including Tiam1 and ArhGAP9, that demonstrates specificity for PI(4,5)P(2), as well as for PI(3,4,5)P(3) and PI(3,4)P(2), the products of PI 3-kinase. These PH domain family members utilize a non-canonical phosphoinositide binding pocket related to that employed by beta-spectrin. Crystal structures of the PH domain of ArhGAP9 in complex with the headgroups of Ins(1,3,4)P(3), Ins(1,4,5)P(3), and Ins(1,3,5)P(3) reveal how two adjacent phosphate positions in PI(3,4)P(2), PI(4,5)P(2), and PI(3,4,5)P(3) are accommodated through flipped conformations of the bound phospholipid. We validate the non-canonical site of phosphoinositide interaction by showing that binding pocket mutations, which disrupt phosphoinositide binding in vitro, also disrupt membrane localization of Tiam1 in cells. We posit that the diversity in PI interaction modes displayed by PH domains contributes to their versatility of use in biological systems.

Medulloblastoma, which usually arises in the cerebellum, is the most common malignant brain cancer in children and is still associated with substantial mortality and survivors often suffer from serious life-long therapy-related side effects. In recent years several medulloblastoma subtypes with distinct developmental origins, genetic profiles, pathway signatures, and clinicopathological features have been identified. The current consensus divides medulloblastoma tumors into four subgroups, WNT, sonic hedgehog (Shh), Group 3 and Group 4 allowing for different targeted therapeutic approaches. Not specifically restricted to a defined subgroup, aberrant activation of the epidermal growth factor receptor family (EGFR/ErbB) has been reported in a large percentage of medulloblastoma and has been associated with poor outcome. The Shh pathway is an important signaling pathway involved in cerebellar development. Shh is secreted from the Purkinje cells, and acts as a mitogen for cerebellar granule precursor (CGP) cells. Mutations leading to hyperactive Shh signaling have been associated with improper migration and differentiation of CGP cells and medulloblastoma formation. Still, the molecular targets contributing to Shh-mediated proliferation in these cells are poorly understood. Na,K-ATPase is a membrane protein that maintains intracellular ion homeostasis, and is responsible for generating ion gradients across cell membranes. Consisting of a catalytic alpha subunit and a beta subunit, the enzyme not only pumps sodium ions out and potassium ions into the cell using ATP but also functions a signaling scaffold and a cell adhesion molecule. Changes in Na,K-ATPase function and expression have been reported in various cancers and may contribute to tumor development and progression. We now show that the Na,K-ATPase beta1-subunit is drastically reduced in medulloblastoma tumors of mice with aberrant activation of Shh signaling. In addition, Shh activation prevented the upregulation of the beta1-subunit in primary cultures of normal cerebellar granule cells and the polycomb transcription factor Bmi1 that is induced upon activation of Shh signaling repressed beta1-subunit levels. Furthermore, shRNA-mediated knockdown of the beta1-subunit increased cell proliferation and tumorigenicity of medulloblastoma cells. Nevertheless, cardiac glycosides that inhibit the pump function of Na,K-ATPase inhibited EGF-induced signaling and cell motility suggesting that Na,K-ATPase alpha and beta subunit may have dual functions in CGP cells and medulloblastoma. Citation Format: Zhiqin Li, Alisa Litan, Seung Joon Lee, Bruce Graves, Sonali P. Barwe, Sigrid A. Langhans. Distinct roles of Na,K-ATPase function and expression in medulloblastoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 707. doi:10.1158/1538-7445.AM2015-707