Directly visualized glioblastoma-derived extracellular vesicles transfer RNA to microglia/macrophages in the brain

Background

To understand the ability of gliomas to manipulate their microenvironment, we visualized the transfer of vesicles and the effects of tumor-released extracellular RNA on the phenotype of microglia in culture and in vivo.

Methods

Extracellular vesicles (EVs) released from primary human glioblastoma (GBM) cells were isolated and microRNAs (miRNAs) were analyzed. Primary mouse microglia were exposed to GBM-EVs, and their uptake and effect on proliferation and levels of specific miRNAs, mRNAs, and proteins were analyzed. For in vivo analysis, mouse glioma cells were implanted in the brains of mice, and EV release and uptake by microglia and monocytes/macrophages were monitored by intravital 2-photon microscopy, immunohistochemistry, and fluorescence activated cell sorting analysis, as well as RNA and protein levels.

Results

Microglia avidly took up GBM-EVs, leading to increased proliferation and shifting of their cytokine profile toward immune suppression. High levels of miR-451/miR-21 in GBM-EVs were transferred to microglia with a decrease in the miR-451/miR-21 target c-Myc mRNA. In in vivo analysis, we directly visualized release of EVs from glioma cells and their uptake by microglia and monocytes/macrophages in brain. Dissociated microglia and monocytes/macrophages from tumor-bearing brains revealed increased levels of miR-21 and reduced levels of c-Myc mRNA.

Conclusions

Intravital microscopy confirms the release of EVs from gliomas and their uptake into microglia and monocytes/macrophages within the brain. Our studies also support functional effects of GBM-released EVs following uptake into microglia, associated in part with increased miRNA levels, decreased target mRNAs, and encoded proteins, presumably as a means for the tumor to manipulate its environs.     

Molecular subgroups of medulloblastoma identification using noninvasive magnetic resonance spectroscopy

Background

Medulloblastomas in children can be categorized into 4 molecular subgroups with differing clinical characteristics, such that subgroup determination aids in prognostication and risk-adaptive treatment strategies. Magnetic resonance spectroscopy (MRS) is a widely available, noninvasive tool that is used to determine the metabolic characteristics of tumors and provide diagnostic information without the need for tumor tissue. In this study, we investigated the hypothesis that metabolite concentrations measured by MRS would differ between molecular subgroups of medulloblastoma and allow accurate subgroup determination.

Methods

MRS was used to measure metabolites in medulloblastomas across molecular subgroups (SHH = 12, Groups 3/4 = 17, WNT = 1). Levels of 14 metabolites were analyzed to determine those that were the most discriminant for medulloblastoma subgroups in order to construct a multivariable classifier for distinguishing between combined Group 3/4 and SHH tumors.

Results

Medulloblastomas across molecular subgroups revealed distinct spectral features. Group 3 and Group 4 tumors demonstrated metabolic profiles with readily detectable taurine, lower levels of lipids, and high levels of creatine. SHH tumors showed prominent choline and lipid with low levels of creatine and little or no evidence of taurine. A 5-metabolite subgroup classifier inclusive of creatine, myo-inositol, taurine, aspartate, and lipid 13a was developed that could discriminate between Group 3/4 and SHH medulloblastomas with excellent accuracy (cross-validated area under the curve [AUC] = 0.88).

Conclusions

The data show that medulloblastomas of Group 3/4 differ metabolically as measured using MRS when compared with SHH molecular subgroups. MRS is a useful and accurate tool to determine medulloblastoma molecular subgroups.     

Assessment of dietary practice among diabetic patients in the United arab emirates

OBJECTIVES: The aim of this study was to assess dietary practices and risk profile (hypertension, obesity, lipid profile and glycemic control) among people with diabetes in Al-Ain District, United Arab Emirates (UAE). METHODS: During 2006, we performed a cross-sectional study of diabetic patients attending diabetic outpatient clinics at Tawam Hospital and primary health care centers in Al-Ain District. Subjects completed an interviewer-administered questionnaire, blood pressure, body mass index, percentage body fat and abdominal circumference were measured and recorded and the most recent HbA1c levels and fasting lipid profile were identified. RESULTS: A sample of 409 diabetic patients was recruited, 50% of whom were illiterate. Only 24% read food labeling. 76% reported being unable to distinguish clearly between low and high carbohydrate index food items and no one reported counting calorie intake. 46% reported that they had never been seen by dietician since their diagnosis. Their overall risk profile, notably body weight, lipid profile and blood pressure, was very unfavorable; more than half of the study sample had uncontrolled hypertension and uncontrolled lipid profile and the majority was overweight (36%) or obese (45%). Abdominal obesity was particularly common (59%). Only 31% had an HbA1c of less than 7%. CONCLUSIONS: The dietary practices of diabetic patients in the UAE are inadequate and need improvement.     

The nasopharyngeal microbiota in patients with viral respiratory tract infections is enriched in bacterial pathogens

The nasopharynx is the primary site of colonization by respiratory pathogen that constitutes the port of entrance in the respiratory tract. The role of mucosal respiratory microbiota in infection has been recently emphasized; therefore, we aimed to assess if a specific respiratory microbiota profile was associated with symptomatic infection and/or with presence of respiratory viruses. We performed a case-control study to characterize the healthy respiratory microbiota and its alteration during acute viral infections. Next-generation sequencing of the 16S rRNA gene was applied to 225 nasopharyngeal samples from 177 patients with viral respiratory infection and 48 matched healthy controls. We evidenced an important decrease of bacterial alpha-diversity in patients with symptomatic respiratory infection and a loss of the healthy core microbiota, specifically anaerobes and Prevotella spp. Moreover, eight respiratory pathogens were enriched in these patients, including Staphylococcus aureus, Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis, Dol osigranulum pigrum and Corynebacterium propinquum/pseudodiphtheriticum, whose role in respiratory infection is unclear. The asymptomatic carrier of influenza harbors a microbiota similar to healthy subjects, suggesting a critical role of microbiota in the clinical expression of viruses. These data suggest that the commensal microbiota plays a significant role in susceptibility to viral infection. The frequent co-detection of virus and bacteria raises the question of a strategy to prevent bacterial disease, focusing on the prevention of nasopharyngeal colonization through effective antibiotic treatment. In addition to antibiotics, further studies should test preventive or therapeutic interventions for maintaining or restoring a healthy nasopharyngeal microbiota.     

Feeling-of-knowing in episodic memory: an event-related fMRI study

An individual may fail to recall an item from memory but still feel that it would be recognized on a later test, a retrieval state termed the "feeling-of-knowing" (FOK). In this study we used event-related fMRI and the FOK to examine both encoding- and retrieval-related factors that are associated with different levels of recall performance: successful retrieval of a previously studied item, retrieval failure accompanied by the FOK, and retrieval failure without any FOK. The results revealed one predominant pattern of retrieval-related activation: an intermediate level of activation for FOK-less than that associated with successful recall and greater than that associated with unsuccessful recall (frontal and left parietal cortices). Two further patterns were also observed: greater activation for both successful recall and FOK than for unsuccessful recall (left midlateral prefrontal cortex) and greater activation for successful recall than for both FOK and unsuccessful recall (left MTL). Analysis of encoding trials conditional upon subsequent retrieval success revealed a pattern of activation that appeared to predict subsequent recall, but which further analysis indicated to be a better predictor of subsequent recognition. These results provide evidence that the phenomenology of graded recall is represented neurally in frontal and parietal cortices, but that activation at encoding may not precipitate the different levels of recall experience.     

Dexanabinol (HU-211) in the treatment of severe closed head injury: a randomized, placebo-controlled, phase II clinical trial

OBJECTIVE: To establish the safety of intravenous dexanabinol in severe head injury. DESIGN: Prospective, randomized, double-blind, placebo- (vehicle) controlled, multicenter, escalating dose study of a single administration of drug (48 or 150 mg) or vehicle (1 or 3 mL). SETTING: All Israeli neurosurgical intensive care units (a total of six units). PATIENTS: Sixty-seven patients, aged 16-65 yrs, Glasgow Coma Scale score of 4-8, injured within 6 hrs of treatment. MEASUREMENTS AND MAIN RESULTS: Intracranial pressure, cerebral perfusion pressure, blood pressure, and heart rate were measured continuously in the intensive care unit. Adverse medical events were recorded and clinical outcome was assessed by the Glasgow outcome scale throughout a 6-month follow-up period. A highly significant reduction in the percentage of time with intracranial pressure >25, cerebral perfusion pressure <50, and systolic blood pressure <90 mm Hg was observed in the drug-treated group. The nature and incidence of adverse medical events were similar in the two groups. The percentage of patients achieving good neurologic outcome on the Glasgow outcome scale was 21% and 14% higher in the drug-treated group at 3 and 6 months, respectively. Statistical analysis of these differences by a logistic model using dose, entry Glasgow coma scale score, and computed tomograph as covariates yielded p values for the effect of treatment of .03 and .14 at 3 and 6 months, respectively. CONCLUSIONS: Dexanabinol was safe and well tolerated in severe head injury. The treated patients achieved significantly better intracranial pressure/cerebral perfusion pressure control without jeopardizing blood pressure. A trend toward faster and better neurologic outcome was also observed.