Intracellular Trafficking Governs the Processing of the Amyloid Precursor Protein and the Secretion of Beta-Amyloid

One of the hallmarks of Alzheimer’s disease (AD) is the pathological accumulation of β-amyloid (Aβ) in the brains of AD patients. Oligomeric and fibrillar aggregates of Aβ have been shown to be neurotoxic to neurons and hippocampal slices. Therefore, limiting Aβ production is an important area of research in order to delay or stop AD progression. Aβ is produced by amyloidogenic cleavage of amyloid precursor protein (APP). Amyloidogenic cleavage requires ectodomain removal by β-secretase and intramembrane γ-cleavage by γ-secretase to release Aβ products ranging from 38-43 residues. Work from our lab has shown that APP and γ-secretase are resident proteins of the lysosome. Furthermore, the acidic environment of lysosomes that promotes the aggregation of Aβ. While many lines of evidence demonstrate that APP internalization is important to the Aβ production, the intracellular itinerary of APP, from production to cleavage, is unclear. In order to follow the intracellular trafficking of APP and Aβ, we have applied various microscopy techniques, in combination with fluorescently-tagged proteins. Using a photoactivatable mutant of GFP (paGFP), we accurately photoactivated nascent APP and followed its trafficking to lysosomes. To our surprise, we found that APP was delivered to lysosomes, where it is cleaved by γ-secretase, through an entirely intracellular pathway. This intracellular pathway was dependent upon an interaction between APP and adaptor protein 3. We found that the interaction between APP and AP-3 is dependent on the 709YTSI712 tyrosine motif. Furthermore, phosphorylation of the serine within this motif, by PKCε, can disrupt this interaction. By decreasing APP trafficking to lysosomes, through disrupting the APP/AP-3 interaction we decreased the production of Aβ. While lysosomes have traditionally been thought to be responsible for cellular waste disposal, they also have a secretory role in a number of cell types; including neurons. We demonstrate that lysosomes are not only responsible for the production of Aβ, but may also be responsible for the secretion of lysosomal Aβ into the extracellular space. This research may provide new therapeutic targets to limit the production and release of Aβ

Prolonged myoclonus after a single bolus dose of propofol

Propofol is a commonly used anaesthetic agent and is rarely associated with seizure-like phenomena. This case report presents a young woman with seizure-like phenomena lasting more than 4 weeks after a single dose of propofol. The underlying pathophysiology of this condition is poorly understood but a psychological component is possible in this case. © 2009 The Authors.postprin

Aspects of high density effective theory in QCD

We study an effective theory of QCD at high density in detail, including the finite temperature effects and the leading order correction in $1/\mu$ expansion. We investigate the Cooper pair gap equation and find that the color-flavor locking phase is energetically preferred at high density. We also find the color-superconducting phase transition occurs in dense quark matter when the chemical potential is larger than $250\pm 100~{\rm MeV}$ and the temperature is lower than 0.57 times the Cooper pair gap in the leading order in the hard-dense-loop approximation. The quark-neutrino four-Fermi coupling and the quark-axion coupling receive significant corrections in dense quark matter.Comment: 23 pages, 5 figures. The gap equations are re-analyzed in the HDL approximatio

Promotion of knowledge and awareness of parents in HK about infant oral health care

Aim: To promote the knowledge and awareness of infant oral health (OH) care among Hong Kong parents with children aged 0 to 2 years through an interactive workshop and to evaluate its effectiveness. Methods: Parents were recruited from government-registered childcare centers and private playgroups. Interactive workshops consisted of a 30-minute PowerPoint presentation and 20 minutes of small-group activities, which included infant oral hygiene instruction with custom-made infant dentition models, diet analysis and question-and-answer session. Self-completed questionnaires used to evaluate the knowledge and attitude of parents were distributed before and after the workshops. Scores on general OH knowledge (range=0-18), infant OH knowledge (0-10) and parent’s attitude (0-4) were computed. Scores of at least 70% were considered proficient. Results: Among the 111 participants (aged 26 to 54 years, 64% mothers), 96% had a child aged 0 to 30 months. 30% had their children’s mouth cleaned at least twice a day. Only one participant had brought his/her child to see a dentist. Weaker aspects in parents’ OH knowledge and common misconceptions were identified in the pre-survey. Only 35% identified frequent meals as an increased caries risk; only 59% and 79% identified starchy food and formula milk as cariogenic food respectively. 58% did not know water fluoridation can prevent caries, while 33% of parents pointed out calcium supplement can prevent caries. Before the workshop, 41% had proficient general OH knowledge (mean=11.9) and 16% had proficient infant OH knowledge (mean=4.8). Over half of parents showed positive attitude (mean=3.4). Significant improvements in general OH knowledge (mean=15.6, p<0.001), infant OH knowledge (mean=8.8, p<0.001) and attitude (mean=3.9, p<0.001) were observed. Parents reflected the workshops were useful (94%) and they learned new practices to improve their infants’ OH (95%). Conclusion: Several deficiencies in oral health knowledge and behaviour are identified. The interactive workshops can effectively promote the knowledge and awareness of infant oral health care among parents with children aged 0 to 2 years. Large-scale infant oral health survey is needed. Interactive workshops with longer follow-up periods are recommended. More guidelines can be provided to parents and general dentists for prevention of caries.published_or_final_versio

Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context

Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts

Pan-cancer Alterations of the MYC Oncogene and Its Proximal Network across the Cancer Genome Atlas

Although theMYConcogene has been implicated incancer, a systematic assessment of alterations ofMYC, related transcription factors, and co-regulatoryproteins, forming the proximal MYC network (PMN),across human cancers is lacking. Using computa-tional approaches, we define genomic and proteo-mic features associated with MYC and the PMNacross the 33 cancers of The Cancer Genome Atlas.Pan-cancer, 28% of all samples had at least one ofthe MYC paralogs amplified. In contrast, the MYCantagonists MGA and MNT were the most frequentlymutated or deleted members, proposing a roleas tumor suppressors.MYCalterations were mutu-ally exclusive withPIK3CA,PTEN,APC,orBRAFalterations, suggesting that MYC is a distinct onco-genic driver. Expression analysis revealed MYC-associated pathways in tumor subtypes, such asimmune response and growth factor signaling; chro-matin, translation, and DNA replication/repair wereconserved pan-cancer. This analysis reveals insightsinto MYC biology and is a reference for biomarkersand therapeutics for cancers with alterations ofMYC or the PMN

Genomic, Pathway Network, and Immunologic Features Distinguishing Squamous Carcinomas

This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing molecular features of squamous cell carcinomas (SCCs) from five sites associated with smokin