Development of an osteosarcoma model with MYCN amplification and TP53 mutation in hiPS cell-derived neural crest cells.

Mesenchymal stem cell- or osteoblast-derived osteosarcoma is the most common malignant bone tumor. Its highly metastatic malignant phenotypes, which are often associated with a poor prognosis, have been correlated with the modulation of TP53- and cell-cycle-related pathways. MYC, which regulates the transcription of cell-cycle modulating genes, is used as a representative prognostic marker for osteosarcoma. Another member of the MYC oncoprotein family, MYCN, is highly expressed in a subset of osteosarcoma, however its roles in osteosarcoma have not been fully elucidated. Here, we attempted to create an in vitro tumorigenesis model using hiPSC-derived neural crest cells, which are precursors of mesenchymal stem cells, by overexpressing MYCN on a heterozygous TP53 hotspot mutation (c.733G>A; p.G245S) background. MYCN-expressing TP53 mutated transformed clones were isolated by soft agar colony formation, and administered subcutaneously into the periadrenal adipose tissue of immunodeficient mice, resulting in the development of chondroblastic osteosarcoma. MYCN suppression decreased the proliferation of MYCN-induced osteosarcoma cells, suggesting MYCN as a potential target for a subset of osteosarcoma treatment. Further, comprehensive analysis of gene expression and exome sequencing of MYCN-induced clones indicated osteosarcoma-specific molecular features, such as the activation of TGF-ß signaling and DNA copy number amplification of GLI1. The model of MYCN-expressing chondroblastic osteosarcoma was developed from hiPSC-derived neural crest cells, providing a useful tool for the development of new tumor models using hiPSC-derived progenitor cells with gene modifications and in vitro transformation.

Genome-wide characterization of aspartic protease (AP) gene family in Populus trichocarpa and identification of the potential PtAPs involved in wood formation.

BACKGROUND: Aspartic protease (AP) is one of four large proteolytic enzyme families that are involved in plant growth and development. Little is known about the AP gene family in tree species, although it has been characterized in Arabidopsis, rice and grape. The AP genes that are involved in tree wood formation remain to be determined. RESULTS: A total of 67 AP genes were identified in Populus trichocarpa (PtAP) and classified into three categories (A, B and C). Chromosome mapping analysis revealed that two-thirds of the PtAP genes were located in genome duplication blocks, indicating the expansion of the AP family by segmental duplications in Populus. The microarray data from the Populus eFP browser demonstrated that PtAP genes had diversified tissue expression patterns. Semi-qRT-PCR analysis further determined that more than 10 PtAPs were highly or preferentially expressed in the developing xylem. When the involvement of the PtAPs in wood formation became the focus, many SCW-related cis-elements were found in the promoters of these PtAPs. Based on PtAPpromoter::GUS techniques, the activities of PtAP66 promoters were observed only in fiber cells, not in the vessels of stems as the xylem and leaf veins developed in the transgenic Populus tree, and strong GUS signals were detected in interfascicular fiber cells, roots, anthers and sepals of PtAP17promoter::GUS transgenic plants. Intensive GUS activities in various secondary tissues implied that PtAP66 and PtAP17 could function in wood formation. In addition, most of the PtAP proteins were predicted to contain N- and (or) O-glycosylation sites, and the integration of PNGase F digestion and western blotting revealed that the PtAP17 and PtAP66 proteins were N-glycosylated in Populus. CONCLUSIONS: Comprehensive characterization of the PtAP genes suggests their functional diversity during Populus growth and development. Our findings provide an overall understanding of the AP gene family in trees and establish a better foundation to further describe the roles of PtAPs in wood formation.

A Novel Two-Stage Generation Framework for Promoting the Persona-Consistency and Diversity of Responses in Neural Dialog Systems.

Although quite natural for human beings to communicate based on their own personality in daily life, it is rather challenging for neural dialog systems to do the same. This is because the general dialog systems are difficult to generate diverse responses while at the same time maintaining consistent persona information. Existing methods basically focus on merely one of them, ignoring either of them will reduce the quality of dialog. In this work, we propose a two-stage generation framework to promote the persona-consistency and diversity of responses. In the first stage, we propose a persona-guided conditional variational autoencoder (persona-guided CVAE) to generate diverse responses, and the main difference when compared with general CVAE-based model is that we use additional dialog attribute to assist the latent variables to encode the effective information in the response and further use it as a guiding vector for response generation. In the second stage, we employ persona-consistency checking module and the response rewriting module to mask the inconsistent word in the generated response prototype and rewrite it to more consistent. Automatic evaluation results demonstrate that the proposed model is able to generate diverse and persona-consistent responses.

Serum metabolomics analysis in patients with alcohol dependence.

Objective: Alcohol dependence (AD) is a chronic recurrent mental disease caused by long-term drinking. It is one of the most prevalent public health problems. However, AD diagnosis lacks objective biomarkers. This study was aimed to shed some light on potential biomarkers of AD patients by investigating the serum metabolomics profiles of AD patients and the controls. Methods: Liquid chromatography-mass spectrometry (LC-MS) was used to detect the serum metabolites of 29 AD patients (AD) and 28 controls. Six samples were set aside as the validation set (Control: n = 3; AD group: n = 3), and the remaining were used as the training set (Control: n = 26; AD group: n = 25). Principal component analysis (PCA) and partial least squares discriminant analysis (PCA-DA) were performed to analyze the training set samples. The metabolic pathways were analyzed using the MetPA database. The signal pathways with pathway impact >0.2, value of p <0.05, and FDR < 0.05 were selected. From the screened pathways, the metabolites whose levels changed by at least 3-fold were screened. The metabolites with no numerical overlap in their concentrations in the AD and the control groups were screened out and verified with the validation set. Results: The serum metabolomic profiles of the control and the AD groups were significantly different. We identified six significantly altered metabolic signal pathways, including protein digestion and absorption; alanine, aspartate, and glutamate metabolism; arginine biosynthesis; linoleic acid metabolism; butanoate metabolism; and GABAergic synapse. In these six signal pathways, the levels of 28 metabolites were found to be significantly altered. Of these, the alterations of 11 metabolites changed by at least 3-fold compared to the control group. Of these 11 metabolites, those with no numerical overlap in their concentrations between the AD and the control groups were GABA, 4-hydroxybutanoic acid, L-glutamic acid, citric acid and L-glutamine. Conclusion: The metabolite profile of the AD group was significantly different from that of the control group. GABA, 4-hydroxybutanoic acid, L-glutamic acid, citric acid, and L-glutamine could be used as potential diagnostic markers for AD.

[Clinical significance of 5-HT and DA levels in serum and cerebrospinal fluid of the patients with delayed encephalopathy after acute carbon monoxide poisoning].

OBJECTIVE: To explore the changes and the clinical significance of 5-hydroxytryptamine (5-HT), dopamine (DA) levels in serum and cerebrospinal fluid (CSF) of patients with delayed encephalopathy (DEACMP) after acute carbon monoxide poisoning. METHODS: The dynamic detection of 5-HT and DA levels in serum and CSF from 42 patients with DEACMP was performed with high performance liquid chromatography (HPLC). The condition changes of patients with DEACMP were analyzed with three types of scales: the activity of daily living scale (ADL), information memory concentration test (IMCT) and Hasegawa's dementia scale (HDS); these changes were compared with those from 38 other encephalopathy patients and 38 non-encephalopathy patients, respectively. RESULTS: Before treatment, the serum 5-HT and DA levels [(662.61 ± 178.50) and (155.74 ± 60.32) nmol/L, respectively] of DEACMP group were both significantly lower than those [(914.08 ± 198.04) and (225.70 ± 48.53) nmol/L] of non-encephalopathy group (P < 0.05); the serum DA level of DEACMP group was also significantly lower than that [(243.57 ± 66.94) nmol/L] of other encephalopathy group (P < 0.05); the serum 5-HT level of DEACMP group was not significantly different from that [(729.54 ± 299.87) nmol/L] of other encephalopathy group (P > 0.05). After treatment, the serum 5-HT and DA levels [(714.08 ± 170.47) and (192.18 ± 33.07 nmol/L, respectively)] of DEACMP group elevated to various extent, but only serum DA level was significantly higher than that before treatment (P < 0.05). Before treatment, the CSF 5-HT and DA levels of DEACMP group were significantly lower than those of non-encephalopathy group and those of other encephalopathy group (P < 0.05). After treatment, the CSF 5-HT level (232.44 ± 54.28 nmol/L) was similar to normal level and significantly higher than that before treatment (P < 0.05); the CSF DA level [(56.83 ± 12.85) nmol/L] of DEACMP group increased only slightly (P > 0.05). In DEACMP group, ADL score (50.64 ± 7.23), HDS score (8.55 ± 8.08) and IMCT score (4.95 ± 7.30) before treatment were significantly different from those (8.5 ± 8.08, 4.95 ± 7.30 and 15.64 ± 10.90) after treatment (P < 0.01). In DEACMP group, there wasa negative correlation between DA level changes and HDS score changes, when the DA levels and HDS scores before treatment were compared with those after treatment (P < 0.05). CONCLUSION: The dynamic changes of 5-HT and DA levels in serum and CSF of patients with DEACMP consisted basically with the patient's condition change. The dynamically detected 5-HT and DA levels can be used as the biological indicators to reflect the condition change and treatment effects of DEACMP patients.

Urine-derived induced pluripotent/neural stem cells for modeling neurological diseases.

Neurological diseases are mainly modeled using rodents through gene editing, surgery or injury approaches. However, differences between humans and rodents in terms of genetics, neural development, and physiology pose limitations on studying disease pathogenesis in rodent models for neuroscience research. In the past decade, the generation of induced pluripotent stem cells (iPSCs) and induced neural stem cells (iNSCs) by reprogramming somatic cells offers a powerful alternative for modeling neurological diseases and for testing regenerative medicines. Among the different somatic cell types, urine-derived stem cells (USCs) are an ideal cell source for iPSC and iNSC reprogramming, as USCs are highly proliferative, multipotent, epithelial in nature, and easier to reprogram than skin fibroblasts. In addition, the use of USCs represents a simple, low-cost and non-invasive procedure for generating iPSCs/iNSCs. This review describes the cellular and molecular properties of USCs, their differentiation potency, different reprogramming methods for the generation of iPSCs/iNSCs, and their potential applications in modeling neurological diseases.

Photocatalytic Protein Damage by Silver Nanoparticles Circumvents Bacterial Stress Response and Multidrug Resistance.

Silver nanoparticles (AgNPs) are known for their broad-spectrum antibacterial properties, especially against antibiotic-resistant bacteria. However, the bactericidal mechanism of AgNPs remains unclear. In this study, we found that the bactericidal ability of AgNPs is induced by light. In contrast to previous postulates, visible light is unable to trigger silver ion release from AgNPs or to promote AgNPs to induce reactive oxygen species (ROS) in Escherichia coli In fact, we revealed that light excited AgNPs to induce protein aggregation in a concentration-dependent manner in E. coli, indicating that the bactericidal ability of AgNPs relies on the light-catalyzed oxidation of cellular proteins via direct binding to proteins, which was verified by fluorescence spectra. AgNPs likely absorb the light energy and transfer it to the proteins, leading to the oxidation of proteins and thus promoting the death of the bacteria. Isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomics revealed that the bacteria failed to develop effective resistance to the light-excited AgNPs. This direct physical mechanism is unlikely to be counteracted by any known drug resistance mechanisms of bacteria and therefore may serve as a last resort against drug resistance. This mechanism also provides a practical hint regarding the antimicrobial application of AgNPs-light exposure improves the efficacy of AgNPs.IMPORTANCE Although silver nanoparticles (AgNPs) are well known for their antibacterial properties, the mechanism by which they kill bacterial cells remains a topic of debate. In this study, we uncovered the bactericidal mechanism of AgNPs, which is induced by light. We tested the efficacy of AgNPs against a panel of antimicrobial-resistant pathogens as well as Escherichia coli under conditions of light and darkness and revealed that light excited the AgNPs to promote protein aggregation within the bacterial cells. Our report makes a significant contribution to the literature because this mechanism bypasses microbial drug resistance mechanisms, thus presenting a viable option for the treatment of multidrug-resistant bacteria.

Cytotoxicity of Silver Nanoparticles Against Bacteria and Tumor Cells.

With the rapid increase of multiple drug-resistant bacteria, silver nanoparticles (AgNPs) with broad-spectrum antibacterial activities have been widely applied in the treatment of bacterial infection. Meanwhile, AgNPs also have anticancer activities against different cell lines. The toxic effects of AgNPs depend on concentration, size, shape, coated materials and surrounding environments. In order to better understand the antibacterial and antitumor effects of AgNPs, various investigations have been carried out to uncover the molecular mechanism of action. This review summarizes the recent studies on the action mechanisms of AgNPs related to their antibacterial activities including collapsing cell walls, inducing reactive oxygen species, inhibiting aerobic respiration and damaging DNA and their antitumor effects including impairing mitochondria, blocking cell cycle, and activating apoptosis. In these investigations, the systematic approaches have not been extensively applied. Increasingly matured omics techniques including genomics, transcriptomic, translatomics and proteomics should be more widely explored to provide the comprehensive views of the cytotoxic effects of AgNPs to bacteria and tumor cells and thus globally illustrate the molecular mechanisms of the cytotoxicity, promoting the better medical application of AgNPs in the future.

iTRAQ-Based Proteomics Revealed the Bactericidal Mechanism of Sodium New Houttuyfonate against Streptococcus pneumoniae.

Sodium new houttuyfonate (SNH), an addition product of active ingredient houttuynin from the plant Houttuynia cordata Thunb., inhibits a variety of bacteria, yet the mechanism by which it induces cell death has not been fully understood. In the present study, we utilized iTRAQ-based quantitative proteomics to analyze the protein alterations in Streptococcus pneumoniae in response to SNH treatment. Numerous proteins related to the production of reactive oxygen species (ROS) were found to be up-regulated by SNH, suggesting that ROS pathways may be involved as analyzed via bioinformatics. As reported recently, cellular reactions stimulated by ROS including superoxide anion (O2(•-)), hydrogen peroxide (H2O2), and hydroxyl radicals (OH(•)) have been implicated as mechanisms whereby bactericidal antibiotics kill bacteria. We then validated that SNH killed S. pneumoniae in a dose-dependent manner accompanied by the increasing level of H2O2. On the other hand, the addition of catalase, which can neutralize H2O2 in cells, showed a significant recovery in bacterial survival. These results indicate that SNH indeed induced H2O2 formation to contribute to the cell lethality, providing new insights into the bactericidal mechanism of SNH and expanding our understanding of the common mechanism of killing induced by bactericidal agents.