Compromised ATP binding as a mechanism of phosphoinositide modulation of ATP-sensitive K+ channels

AbstractInhibition of ATP-sensitive K+ (KATP) channels by ATP, a process presumably initiated by binding of ATP to the pore-forming subunit, Kir6.2, is reduced in the presence of phosphoinositides (PPIs). Previous studies led to the hypothesis that PPIs compromise ATP binding. Here, this hypothesis was tested using purified Kir6.2. We show that PPIs bind purified Kir6.2 in an isomer-specific manner, that biotinylated ATP analogs photoaffinity label purified Kir6.2, and that this labeling is weakened in the presence of PPIs. Patch-clamp measurements confirmed that these ATP analogs inhibited Kir6.2 channels, and that PPIs decreased the level of inhibition. These results indicate that interaction of PPIs with Kir6.2 impedes ATP-binding activity. The PPI regulation of ATP binding revealed in this study provides a putative molecular mechanism that is potentially pivotal to the nucleotide sensitivity of KATP channels

Autophagy is involved in oligodendroglial precursor-mediated clearance of amyloid peptide

BACKGROUND: Accumulation of β-amyloid peptides is an important hallmark of Alzheimer\u27s disease (AD). Tremendous efforts have been directed to elucidate the mechanisms of β-amyloid peptides degradation and develop strategies to remove β-amyloid accumulation. In this study, we demonstrated that a subpopulation of oligodendroglial precursor cells, also called NG2 cells, were a new cell type that can clear β-amyloid peptides in the AD transgene mice and in NG2 cell line. RESULTS: NG2 cells were recruited and clustered around the amyloid plaque in the APPswe/PS1dE9 mice, which is Alzheimer\u27s disease mouse model. In vitro, NG2 cell line and primary NG2 cells engulfed β-amyloid peptides through the mechanisms of endocytosis in a time dependent manner. Endocytosis is divided into pinocytosis and phagocytosis. Aβ(42) internalization by NG2 cells was mediated by actin-dependent macropinocytosis. The presence of β-amyloid peptides stimulated the autophagic pathway in NG2 cells. Once inside the cells, the β-amyloid peptides in NG2 cells were transported to lysosomes and degraded by autophagy. CONCLUSIONS: Our findings suggest that NG2 cells are a new cell type that can clear β-amyloid peptides through endocytosis and autophagy

Yes-Associated Protein Expression in Head and Neck Squamous Cell Carcinoma Nodal Metastasis

INTRODUCTION:Yes-associated protein (YAP) is considered an oncogene found amplified in multiple tumors, including head and neck squamous cell carcinoma (HNSCC). However, the role for YAP expression in HNSCC is not understood. Based on the central role of YAP in the hippo pathway, we tested if YAP was associated with the stage of HNSCC progression and metastatic potential. METHODS:To determine the expression of YAP in human benign and HNSCC tissue specimens, immunohistochemical analyses were performed in whole tissue samples and tissue microarrays. The expression of YAP in tissues of microarray was first associated with clinic-pathologic factors and results verified in samples from whole tissue sections. To investigate the role of YAP and p63 in regulating HNSCC epithelial to mesenchymal transition, epithelial and mesenchymal markers were assayed in Fadu and SCC-25 cells, HNSCC cells with endogenously elevated YAP expression and siRNA-mediated expression knockdown. RESULTS:Analysis of human HNSCC tissues suggested YAP expression was elevated in tumors compared to benign tissues and specifically localized at the tumor invasive front (p value < 0.05). But, indexed YAP expression was lower with greater tumor grade (p value  =  0.02). In contrast, p63 expression was primarily elevated in high-grade tumors. Interestingly, both YAP and p63 was strongly expressed at the tumor invasive front and in metastatic HNSCC. Strikingly, we demonstrated YAP expression in the primary HNSCC tumor was associated with nodal metastasis in univariate analysis (p value  =  0.02). However, the knockdown of YAP in Fadu and SCC-25 cell lines was not associated with changes in epithelial to mesenchymal transdifferentiation or p63 expression. CONCLUSION:Together, YAP expression, in combination with p63 can facilitate identification of HNSCC tumors from hyperplastic and benign tissues and the metastatic function of YAP in HNSCC may not be a result of epithelia to mesenchymal transdifferentiation

Detection of intergenic non-coding RNAs expressed in the main developmental stages in Drosophila melanogaster

How many intergenically encoded non-coding RNAs (ncRNAs) are expressed during various developmental stages in Drosophila? Previous analyses in one or a few developmental stages indicated abundant expression of intergenic ncRNAs. However, some reported that ncRNAs have been recently falsified, and, in general, the false positive rate for ncRNA detection is unknown. In this report, we used reverse transcription-PCR (RT-PCR), a more robust method, to detect ncRNAs from the intergenic regions that are expressed in four major developmental stages (6–8 h embryo, 20–22 h embryo, larvae and adult). We tested 1027 regions, ∼10% of all intergenic regions, and detected transcription by RT–PCR. The results from 18 342 RT–PCR experiments revealed evidence for transcription in 72.7% of intergenic regions in the developmental process. The early developmental stage appears to be associated with more abundant ncRNAs than later developmental stages. In the early stage, we detected 43.6% of intergenic regions that encode transcripts in the triplicate RT–PCR experiments, yielding an estimate of 5006 intergenic regions in the entire genome likely encoding ncRNAs. We compared the RT–PCR-related approach with previous tiling array-based approach and observed that the latter method is insensitive to short ncRNAs, especially the molecules less than 120 bp. We measured false positive rates for the analyzed genomic approaches including the RT–PCR and tiling array method

Research on the Evaluation System of Vocational College Teachers’ Teaching Ability in the Digital Economy Era

The era of digital economy promotes the transformation of enterprises and puts forward new requirements for the development of talent ability and higher requirements for the teaching quality of vocational colleges. A scientific and reasonable evaluation system can evaluate the teaching ability of vocational college teachers, accurately locate and solve the problems existing in teaching links, so as to achieve a new leap in the level of vocational college teachers and better meet the needs of the times. Based on the excellent practice achievements of American universities and the iceberg theory model, this paper takes Shanghai Vocational College as an example, and makes a statistical analysis of the data obtained from 208 questionnaires by using analytic hierarchy process, so as to establish a more refined, scientific and timely evaluation system and evaluation rules for teachers’ teaching ability in vocational colleges. The evaluation system takes “students” as the evaluation subject, “teachers” as the evaluation basis, and “evaluation questionnaire” as the evaluation form, including 2 first-level indicators, 5 second-level indicators and 24 third-level indicators

Carrier recombination spatial transfer by reduced potential barrier causes blue/red switchable luminescence in C8 carbon quantum dots/organic hybrid light-emitting devices

The underlying mechanism behind the blue/red color-switchable luminescence in the C8 carbon quantum dots (CQDs)/organic hybrid light-emitting devices (LEDs) is investigated. The study shows that the increasing bias alters the energy-level spatial distribution and reduces the carrier potential barrier at the CQDs/organic layer interface, resulting in transition of the carrier transport mechanism from quantum tunneling to direct injection. This causes spatial shift of carrier recombination from the organic layer to the CQDs layer with resultant transition of electroluminescence from blue to red. By contrast, the pure CQDs-based LED exhibits green–red electroluminescence stemming from recombination of injected carriers in the CQDs

Effect of surface carbon-oxygen complexes during NO reduction by coal char

Eleven coal chars are studied in a laboratory scale fixed bed reactor using a simulated flue gas for NO reduction. XPS are applied to evaluate the distributions of different surface carbon-oxygen complexes on char surface and distinguish their roles in the reaction of NO with carbon in the presence of oxygen. BET and TEM have been employed to characterize the textural and structural properties of these coal chars. It is found that thermally relatively stable C-O species play a more important role compared with (RC)-C-2 = O and O-C = O. Enrichment of surface C-O species on char surface can enhance NO reduction and simultaneously control CO formation. Activated carbon and H2O2-modified activated carbon are also investigated to verify this point. Two different reaction mechanisms, i.e., surface carbon-oxygen complexes involved reactions and directly burn-off unoccupied surface, are put forward to explain different performance exhibited by the samples examined in this work. (C) 2017 Elsevier Ltd. All rights reserved.</p