Inflammation-related Gene Polymorphisms Associated With Childhood Acute Lymphoblastic Leukemia.

BACKGROUND: Acute lymphoblastic leukemia (ALL) is a malignant hematological disease and is often accompanied by a variety of genetic abnormalities. The pathogenesis of inflammation-related single-nucleotide polymorphism (SNP) in children with ALL remains unclear. OBJECTIVE: This study was to discover the association of the SNP sites of some inflammation-related genes and the susceptibility and treatment response of ALL in children, so as to provide personalized treatment for ALL in children. PROCEDURE: One hundred sixty-five childhood ALL patients and 175 age-matched healthy participants were recruited in this study. We investigated the involvement of 31 SNPs of the inflammation-related genes in the pathogenesis and treatment response of childhood ALL. RESULTS: Statistical analysis revealed that rs2280714 in IRF5, rs2297630 in SDF-1, rs4353135 in NLRP3, rs1946518 in interleukin-18 were related to the susceptibility to pediatric ALL. Interleukin-1ß rs16944 SNP was correlated with ALL risk stage in children. Rs7633631 in CD226 and rs10818488 in TRAF1 were related to the minimal residual disease (MRD) on day 15 and day 33. CONCLUSIONS: Certain SNPs of inflammation genes were associated with the susceptibility and treatment response of ALL children. These findings may help in the early detection, diagnostic evaluation, and making individual chemotherapy regimen for ALL children according to the genotype of these sites at the time of initial diagnosis.

Graphene/gold nanoparticle composites for ultrasensitive and versatile biomarker assay using single-particle inductively-coupled plasma/mass spectrometry.

An ultrasensitive and versatile assay for biomarkers has been developed using graphene/gold nanoparticles (AuNPs) composites and single-particle inductively-coupled plasma/mass spectrometry (spICP-MS). Thrombin was chosen as a model biomarker for this study. AuNPs modified with thrombin aptamers were first non-selectively adsorbed onto the surface of graphene oxide (GO) to form GO/AuNPs composites. In the presence of thrombin, the AuNPs desorbed from the GO/AuNPs composites due to a conformation change of the thrombin aptamer after binding with thrombin. The desorbed AuNPs were proportional to the concentration of thrombin and could be quantified by spICP-MS. By counting the individual AuNPs in the spICP-MS measurement, the concentration of thrombin could be determined. This assay achieved an ultralow detection limit of 4.5 fM with a broad linear range from 10 fM to 100 pM. The method also showed excellent selectivity and reproducibility when a complex protein matrix was evaluated. Furthermore, the diversity and ready availability of ssDNA ligands make this method a versatile new technique for ultrasensitive detection of a wide variety of biomarkers in clinical diagnostics.

CD82 supports survival of childhood acute myeloid leukemia cells via activation of Wnt/ß-catenin signaling pathway.

BACKGROUND: Stem cell marker CD82 plays a vital role in the oncogenesis and progression of acute myelogenous leukemia (AML), especially in sharing properties of leukemia stem cells (LSCs). The Wnt/ß-catenin pathway is required for the development of LSCs in AML. The present study aimed to validate whether CD82 supports the survival of LSCs in pediatric AML via activation of Wnt/ß-catenin signaling pathway. METHODS: CD82 expression and its correlation with molecules downstream of Wnt/ß-catenin pathway in samples from pediatric AML patients were analyzed. Forced or downregulated expression of CD82 in AML cells was evaluated for the effects of CD82 on cell proliferation, cycle regulation, apoptosis, and adriamycin chemoresistance and to validate the underlying mechanism. RESULT: Aberrant expression of CD82 in pediatric AML patients was found. CD82 messenger RNA expression correlated positively with downstream molecules of Wnt/ß-catenin pathway in AML children. Knockdown of CD82 induced apoptosis, suppressed growth, and decreased adriamycin chemoresistance in AML cells. CD82 accelerated ß-catenin nuclear location and then stimulated the expression of downstream molecules of Wnt/ß-catenin pathway. CONCLUSION: CD82 regulates the proliferation and chemotherapy resistance of AML cells via activation of the Wnt/ß-catenin pathway, which suggest that the CD82 may be a potential therapeutic target in AML children.

Effects of silica nanoparticles on endolysosome function in primary cultured neurons 1.

Silica nanoparticles (SiNPs) have been used as vehicles for drug delivery, molecular detection, and cellular manipulations in nanoneuromedicine. SiNPs may cause adverse effects in the brain including neurotoxicity, neuroinflammation, neurodegeneration, and enhancing levels of amyloid beta (Aß) protein-all pathological hallmarks of Alzheimer's disease. Therefore, the extent to which SiNPs influence Aß generation and the underlying mechanisms by which this occurs deserve investigation. Our studies were focused on the effects of SiNPs on endolysosomes which uptake, traffic, and mediate the actions of SiNPs. These organelles are also where amyloidogenesis largely originates. We found that SiNPs, in primary cultured hippocampal neurons, accumulated in endolysosomes and caused a rapid and persistent deacidification of endolysosomes. SiNPs significantly reduced endolysosome calcium stores as indicated by a significant reduction in the ability of the lysosomotropic agent glycyl-l-phenylalanine 2-naphthylamide (GPN) to release calcium from endolysosomes. SiNPs increased Aß1-40 secretion, whereas 2 agents that acidified endolysosomes, ML-SA1 and CGS21680, blocked SiNP-induced deacidification and increased generation of Aß1-40. Our findings suggest that SiNP-induced deacidification of and calcium release from endolysosomes might be mechanistically linked to increased amyloidogenesis. The use of SiNPs might not be the best nanomaterial for therapeutic strategies against Alzheimer's disease and other neurological disorders linked to endolysosome dysfunction.

Aggregation-based determination of mercury(II) using DNA-modified single gold nanoparticle, T-Hg(II)-T interaction, and single-particle ICP-MS.

An ultrasensitive assay is described for the detection and determination of Hg2+(aq) in water samples based on single-particle inductively-coupled plasma/mass spectrometry (spICP-MS). In the presence of Hg2+(aq), AuNPs modified with a segment of single-stranded DNA aggregate due to the formation of the well-known thymine (T)-Hg2+-T complex. Single particle (sp) ICP-MS is used quantify the degree of aggregation by the overall decrease in number of detected AuNPs or NP aggregates. Compared with most other Hg2+ assays that use the same principle of aggregation-dispersion with DNA modified AuNPs, this method has a much lower detection limit of (0.031 ng L-1, 155 fM) and a wider (10,000-fold) linear range (up to 1 µg L-1). The method also showed good practical potential because of its minimal interference from the water sample matrix. Graphical abstractSchematic representation of Hg2+ determination by using modified AuNP probes measured by spICP-MS. AuNPs pulses detected in ICP-MS is relative to the aggregation status of AuNPs based on thymine-Hg2+-thymine interaction.

Study of Fluorescence Quenching Ability of Graphene Oxide with a Layer of Rigid and Tunable Silica Spacer.

The fluorescence quenching property of graphene oxide (GO) has been newly demonstrated and applied for fluorescence imaging and biosensing. In this work, a new nanostructure was designed for effectively studying the quenching ability of GO. The key element in this design is the fabrication of a layer of rigid and thickness adjustable silica spacer for manipulating the distance between the GO and fluorophores. First, a silica core modified with organic dye molecules was prepared, followed by the formation of a silica shell with a tunable thickness. Afterward, the GO was wrapped around silica nanoparticles based on the electrostatic interaction between the negatively charged GO and positively charged silica. The quenching efficiency of GO to different dye molecules was studied at various spacer thicknesses and varying concentrations of GO. Fluorescence lifetime of fluorophores was measured to determine the quenching mechanism. We found that the quenching efficiency of GO was still around 30% when the distance between dyes and GO was increased to more than 30 nm, which indicated the long-distance quenching ability of GO and confirmed the previous theoretical calculation. The quenching mechanisms were proposed schematically based on our experimental results. We expected that the proposed nanostructure could act as a feasible model for studying GO quenching property and shed light on designing GO-based fluorescence sensing systems.

Regulation of cell cycle progression by forkhead transcription factor FOXO3 through its binding partner DNA replication factor Cdt1.

To ensure genome stability, DNA must be replicated once and only once during each cell cycle. Cdt1 is tightly regulated to make sure that cells do not rereplicate their DNA. Multiple regulatory mechanisms operate to ensure degradation of Cdt1 in S phase. However, little is known about the positive regulators of Cdt1 under physiological conditions. Here we identify FOXO3 as a binding partner of Cdt1. FOXO3 forms a protein complex with Cdt1, which in turn blocks its interaction with DDB1 and PCNA. Conversely, FOXO3 depletion facilitated the proteolysis of Cdt1 in unperturbed cells. Intriguingly, FOXO3 deficiency resulted in impaired S-phase entry and reduced cell proliferation. We provide data that FOXO3 knockdown mimics Cdt1 down-regulation and affects G1/S transitions. Our results demonstrate a unique role of FOXO3 in binding to Cdt1 and maintaining its level required for cell cycle progression.

Screening of DNA aptamers against myoglobin using a positive and negative selection units integrated microfluidic chip and its biosensing application.

An aptamer screening method using a positive and negative selection units integrated microfluidic chip was introduced. Here, myoglobin (Myo), one of the early markers to increase after acute myocardial infarction, was used as the model. After 7-round selection, the aptamers, which exhibited dissociation constants (K(d)) in the nanomolar range (from 4.93 to 6.38 nM), were successfully obtained using a positive and negative selection units integrated microfluidic chip. The aptamer with the highest affinity (K(d) = 4.93 nM) was then used for the fabrication of a label-free supersandwich electrochemical biosensor for Myo detection based on target-induced aptamer displacement. The detection limit of this aptamer-based electrochemical biosensor was 10 pM, which was significantly lower than that of those previous antibody-based biosensors for Myo detection. This work may not only develop a strategy for screening aptamer but also offer promising alternatives to the traditional analytical and immunological methods for Myo detection.

Enhanced synergetic antibacterial activity by a reduce graphene oxide/Ag nanocomposite through the photothermal effect.

Multidrug-resistant (MDR) bacterial strains have led to notable heathy threats to human beings. The demand for the development of effective antibacterial materials is increasing. Silver nanoparticles (AgNPs) and graphene-based nanomaterials are two major types of nanomaterials that are studied to inhibit and/or kill bacteria. In this study, by combining the excellent photothermal effect of graphene and antibacterial activity of AgNPs, we have applied reduced graphene oxide/silver (RGO/Ag) nanocomposite to destroy the MDR bacteria. The antibacterial activity of the RGO/Ag nanocomposite was systematically investigated using a regular bacterium of Escherichia coli (E. coli) and an MDR bacterium of Klebsiella pneumoniae (Kp). Compared with AgNPs, graphene oxide (GO) and RGO, the RGO/Ag nanocomposite showed significant higher antibacterial efficiency for both regular bacteria and MDR bacteria. Under a near-infrared (NIR) irradiation (0.30 W/cm2 for 10 min), the RGO/Ag nanocomposite demonstrated an enhanced synergetic antibacterial activity through the photothermal effect. Nearly 100 % of E. coli and Kp were killed by the treatment of 15 µg/mL and 30 µg/mL of RGO/Ag nanocomposite, respectively. Moreover, a membrane integrity assay and a reactive oxygen species (ROS) assay demonstrated that the RGO/Ag nanocomposite under NIR irradiation induced the cell membrane disruption and generation of ROS, providing possible mechanisms for their high antibacterial activity besides the photothermal effect. Finally, the cytotoxicity of the RGO/Ag nanocomposites toward different mammalian cells was studied, the cell viabilities retained above 60 % at higher concentrations of RGO/Ag, indicating that the RGO/Ag nanocomposites may be a low cytotoxic, efficient antibacterial agent with the irradiation.

Reduced Graphene Oxide/Mesoporous Silica Nanocarriers for pH-Triggered Drug Release and Photothermal Therapy.

A sandwich structured bifunctional nanocarrier (rGO@msilica) composed of an inner layer of reduced graphene oxide (rGO) and an outer layer of mesoporous silica (msilica) was developed for synergistic chemo-photothermal therapy. The rGO@msilica not only acted as a pH-triggered drug nanocarrier but also worked as a near-infrared (NIR) photothermal agent. The loaded drug, doxorubicin (DOX), in the rGO@msilica nanocarrier was controllably released in the acidic tumor microenvironment. Moreover, the cancer cells were ablated by laser irradiation (808 nm), contributing to the high photothermal conversion efficiency of the rGO core. With this two-in-one system, in vitro cancer cell experiments indicated that the synergistic therapeutic strategy was superior to those of single modality therapy. These findings imply that the bifunctional rGO@msilica nanocarrier could provide a powerful platform for cancer therapy.

Biocompatible G-Quadruplex/Hemin for Enhancing Antibacterial Activity of H2O2.

The G-quadruplex/hemin (G/H) complex has been broadly used in the field of bioanalytical chemistry for peroxidase-mimicking applications. The property of the G/H complex makes it possible to catalyze the decomposition of H2O2. The hydroxyl radical (·OH) generated during the procedure has a higher antibacterial performance than the original H2O2. Herein, an efficient and biocompatible antibacterial system, which provides the same antibacterial efficiency at lower H2O2 concentration to alleviate the H2O2 toxicity, has been demonstrated based on the conversion of H2O2 to ·OH. With the G/H complex as the additive, the antibacterial activity of H2O2 was vastly enhanced against both Gram-positive and Gram-negative bacteria in in vitro experiments. Furthermore, the designed antibacterial system was applied on the mice wound model in vivo and showed outstanding antibacterial activity of the G/H complex to prevent wound infection and facilitate wound healing. Our study renders the possibility of using the G/H complex to help control both Gram-positive and Gram-negative infections.

Graphene Oxide-Based Biocompatible 3D Mesh with a Tunable Porosity and Tensility for Cell Culture.

One of the major challenges associated with modeling the influence of the cellular microenvironment on cell growth and differentiation is finding suitable substrates for growing the cells in a manner that recapitulates the cell-cell and cell-microenvironmental interactions in vitro. As one approach to address this challenge, we have developed graphene oxide (GO)-3D mesh with tunable hardness and porosity for application in cell culture systems. The synthetic method of GO-3D mesh is simple, easily reproducible, and low cost. The foundation of the method is the combination of poly(ethylene)(glycol) (PEG) and GO together with a salt-leaching approach (NaCl) in addition to a controlled application of heat during the synthetic process to tailor the mechanical properties, porosity, and pore-size distribution of the resulting GO-3D mesh. With this methodology, the hydrogel formed by PEG and GO generates a microporous mesh in the presence of the NaCl, leading to the formation of a stable 3D scaffold after extensive heating and washing. Varying the ratio of NaCl to GO controls porosity, pore size, and pore connectivity for the GO-3D mesh. When the porosity is less than 90%, with an increasing ratio of NaCl to GO, the number of pores increases with good interconnectivity. The 3D-mesh showed excellent biocompatibility with vascular cells which can take on a morphology comparable to that observed in vessels in vivo. Cell proliferation and gene expression can be determined from cells grown on the GO-3D scaffold, providing a valuable tool for investigating cell-microenvironmental changes. The GO-3D mesh described results from the synergy of the combined chemical properties of the PEG and GO with the salt-leaching methodology to generate a unique and flexible mesh that can be modified and optimized for a variety of in vitro applications.

One-Pot Synthesis of Reduced Graphene Oxide/Metal (Oxide) Composites.

Graphene, one of the most attractive two-dimensional nanomaterials, has demonstrated a broad range of applications because of its excellent electronic, mechanical, optical, and chemical properties. In this work, a general, environmentally friendly, one-pot method for the fabrication of reduced graphene oxide (RGO)/metal (oxide) (e.g., RGO/Au, RGO/Cu2O, and RGO/Ag) composties was developed using glucose as the reducing agent and the stabilizer. The glucose not only reduced GO effectively to RGO but also reduced the metal precursors to form metal (oxide) nanoparticles on the surface of RGO. Moreover, the RGO/metal (oxide) composites were stabilized by gluconic acid on the surface of RGO. The developed RGO/metal (oxide) composites were characterized using STEM, FE-SEM, EDS, UV-vis absorption spectroscopy, XRD, FT-IR, and Raman spectroscopy. Finally, the developed nanomaterials were successfully applied as an electrode catalyst to simultaneous electrochemical analysis of l-ascorbic acid, dopamine, and uric acid.

Graphene oxide as an efficient antimicrobial nanomaterial for eradicating multi-drug resistant bacteria in vitro and in vivo.

Graphene is a novel two-dimensional nanomaterial with a growing number of practical applications across numerous fields. In this work, we explored potential biomedical applications of graphene oxide (GO) by systematically studying antibacterial capacity of GO in both macrophages and animal models. Three types of bacteria, including Klebsiella pneumoniae (Kp), Escherichia coli (E. coli) and P. aeruginosa (Pa) were used for in vitro study. Kp was also selected as a representative multidrug resistant (MDR) bacterium for in vivo study. In in vitro study, GO effectively eradicated Kp in agar dishes and thus protected alveolar macrophages (AM) from Kp infection in the culture. In the in vivo evaluation, GO were introduced intranasally into mouse lungs followed by testing organ tissue damage including lung, liver, spleen, and kidneys, polymorphonuclear neutrophil (PMN) penetration, bacterial dissemination, and mortality in Kp-infected mice. We found that GO can prohibit the growth and spread of Kp both in vitro and in vivo, resulting in significantly increased cell survival rate, less tissue injury, subdued inflammatory response, and prolonged mice survival. These findings indicate that GO could be a promising biomaterial for effectively controlling MDR pathogens.