Comprehensive Expression Analyses of Neural Cell-Type-Specific miRNAs Identify New Determinants of the Specification and Maintenance of Neuronal Phenotypes.

MicroRNAs (miRNAs) have been shown to play important roles in both brain development and the regulation of adult neural cell functions. However, a systematic analysis of brain miRNA functions has been hindered by a lack of comprehensive information regarding the distribution of miRNAs in neuronal versus glial cells. To address this issue, we performed microarray analyses of miRNA expression in the four principal cell types of the CNS (neurons, astrocytes, oligodendrocytes, and microglia) using primary cultures from postnatal d 1 rat cortex. These analyses revealed that neural miRNA expression is highly cell-type specific, with 116 of the 351 miRNAs examined being differentially expressed fivefold or more across the four cell types. We also demonstrate that individual neuron-enriched or neuron-diminished RNAs had a significant impact on the specification of neuronal phenotype: overexpression of the neuron-enriched miRNAs miR-376a and miR-434 increased the differentiation of neural stem cells into neurons, whereas the opposite effect was observed for the glia-enriched miRNAs miR-223, miR-146a, miR-19, and miR-32. In addition, glia-enriched miRNAs were shown to inhibit aberrant glial expression of neuronal proteins and phenotypes, as exemplified by miR-146a, which inhibited neuroligin 1-dependent synaptogenesis. This study identifies new nervous system functions of specific miRNAs, reveals the global extent to which the brain may use differential miRNA expression to regulate neural cell-type-specific phenotypes, and provides an important data resource that defines the compartmentalization of brain miRNAs across different cell types.

Heterogeneity of atherosclerotic plaque phenotypes and composition in four different arterial beds: an intravascular ultrasound virtual histology study

Purpose: The purpose of this study was to compare the plaque morphology between coronary and peripheral arteries using intravascular ultrasound (IVUS). Methods: IVUS was performed in 68 patients with coronary and 93 with peripheral artery lesions (29 carotid, 50 renal, and 14 iliac). Plaques were classified as fibroatheroma (VH-FA) (further subclassified as thin-capped [VH-TCFA] and thick-capped [VH-ThCFA]), fibrocalcific plaque (VH-FC) and pathological intimal thickening (VH-PIT). Results: Plaque rupture (13% of coronary, 7% of carotid, 6% of renal, and 7% of iliac arteries; P=NS) and VH-TCFA (37% of coronary, 24% of carotid, 16% of renal, and 7% of iliac arteries; P=0.02) was observed in all arteries. Compared to coronary arteries, VH-FA was less frequently observed in renal (P<0.001) and iliac arteries (P<0.006), while VH-PIT and VH-FC were prevalent in both of these peripheral arteries. Lesions with positive remodeling demonstrated more characteristics of VH-FA in coronary, carotid, and renal arteries compared to those with intermediate/negative remodeling (all P<0.01). There was positive relationship between RI and percent necrotic core area in all four arteries. Conclusions: Atherosclerotic plaque phenotypes were heterogeneous among four different arteries. In contrast, the associations of remodeling mode with plaque phenotype and composition were similar among the various arterial beds.

Propietats protectores de la lipoproteïna de alta densitat (HDL) sobre l'acció inflamatòria de la lipoproteïna de baixa densitat electronegativa (LDL(-)) en monòcits humans

Electronegative low-density lipoprotein (LDL(-)) is a modified fraction of LDL present in peripheral blood whose proportion is elevated in subjects with increased cardiovascular risk. LDL(-) has been shown to have an inflammatory effect on human endothelial cells and mononuclear blood cells. On the other hand, high-density lipoprotein (HDL) is known to have a protective effect against cardiovascular disease, partly mediated by its anti-inflammatory properties. The objective of the current work is to study the putative protective properties of HDL towards the inflammatory effect of LDL(-) in human monocytes, in order to elucidate the mechanisms behind their interaction. Total LDL and HDL were isolated by ultracentrifugation and LDL(-) was obtained from total LDL by anion exchange chromatography. HDL and LDL(-) were incubated together and then re-isolated, and their characteristics were compared to those of untreated lipoproteins. The inflammatory activity of the lipoproteins was determined by incubating monocytes with lipoproteins and measuring cytokine release from the cultured monocytes. The biochemical composition and electrophoretic mobility of the lipoproteins were also determined before and after their interaction. Incubation of HDL with LDL(-) reduced the inflammatory effect of LDL(-) and, in turn, HDL gained inflammatory properties. This indicates a transfer of inflammatory potential taking place during the interaction of LDL(-) and HDL. Additionally, LDL(-) lost non-esterified fatty acids (NEFAs) while HDL gained the same. We conclude that a transfer of NEFAs takes place between LDL(-) and HDL. These observations suggest that NEFAs play a role in the inflammatory effect mediated by LDL(-).

Phenotypes of lung mononuclear phagocytes in HIV seronegative tuberculosis patients: evidence for new recruitment and cell activation

Mycobacterium tuberculosis preferentially resides in mononuclear phagocytes. The mechanisms by which mononuclear phagocytes keep M. tuberculosis in check or by which the microbe evades control to cause disease remain poorly understood. As an initial effort to delineate these mechanisms, we examined by immunostaining the phenotype of mononuclear phagocytes obtained from lungs of patients with active tuberculosis. From August 1994 to March 1995, consecutive patients who had an abnormal chest X-ray, no demostrable acid-fast bacilli in sputum specimens and required a diagnostic bronchoalveolar lavage (BAL) were enrolled. Of the 39 patients enrolled, 21 had microbiologically diagnosed tuberculosis. Thirteen of the 21 tuberculosis patients were either HIV seronegative (n = 12) or had no risk factor for HIV and constituted the tuberculosis group. For comparison, M. tuberculosis negative patients who had BAL samples taken during this time (n = 9) or normal healthy volunteers (n = 3) served as control group. Compared to the control group, the tuberculosis group had significantly higher proportion of cells expressing markers of young monocytes (UCHM1) and RFD7, a marker for phagocytic cells, and increased expression of HLA-DR, a marker of cell activation. In addition, tuberculosis group had significantly higher proportion of cells expressing dendritic cell marker (RFD1) and epithelioid cell marker (RFD9). These data suggest that despite recruitment of monocytes probably from the peripheral blood and local cell activation, host defense of the resident lung cells is insufficient to control M. tuberculosis.

Evolutionary and convergence stability for continuous phenotypes in finite populations derived from two-allele models.

The evolution of a quantitative phenotype is often envisioned as a trait substitution sequence where mutant alleles repeatedly replace resident ones. In infinite populations, the invasion fitness of a mutant in this two-allele representation of the evolutionary process is used to characterize features about long-term phenotypic evolution, such as singular points, convergence stability (established from first-order effects of selection), branching points, and evolutionary stability (established from second-order effects of selection). Here, we try to characterize long-term phenotypic evolution in finite populations from this two-allele representation of the evolutionary process. We construct a stochastic model describing evolutionary dynamics at non-rare mutant allele frequency. We then derive stability conditions based on stationary average mutant frequencies in the presence of vanishing mutation rates. We find that the second-order stability condition obtained from second-order effects of selection is identical to convergence stability. Thus, in two-allele systems in finite populations, convergence stability is enough to characterize long-term evolution under the trait substitution sequence assumption. We perform individual-based simulations to confirm our analytic results.

Changes in nuclear phenotypes following cold shock in Panstrongylus megistus (Burmeister)

The nuclear phenotypes of Malpighian tubule epithelial cells of 5th instar male nymphs of the blood-sucking insect Panstrongylus megistus were studied immediately after a short (1 h) cold shock at 0ºC, and 10 and 30 days later. The objective was to compare the responses to a cold shock with those known to occur after hyperthermia in order to provide insight into the cellular effect of cold in this species. Nuclei which usually exhibited a conspicuous Y chromosome chromocenter were the most frequent phenotype in control and treated specimens. Phenotypes in which the heterochromatin was unravelled, or in which there was nuclear fusion or cell death were more abundant in the shocked specimens. Most of the changes detected have also been found in heat-shocked nymphs, except for nuclear fusion which generates giant nuclei and which appeared to be less effective or necessary than that elicited after heat shock. Since other studies showed that a short cold shock does not affect the survival of more than 14% of 5th instar nymphs of P. megistus with domestic habit and can induce tolerance to a prolonged cold shock, heat shock proteins proteins are probably the best candidates for effective protection of the cells and the insects from drastic damage caused by low temperature shocks.

Effect of sequential heat and cold shocks on nuclear phenotypes of the blood-sucking insect, Panstrongylus megistus (Burmeister) (Hemiptera, Reduviidae)

Thermal shocks induce changes in the nuclear phenotypes that correspond to survival (heterochromatin decondensation, nuclear fusion) or death (apoptosis, necrosis) responses in the Malpighian tubules of Panstrongylus megistus. Since thermal tolerance increased survival and molting rate in this species following sequential shocks, we investigated whether changes in nuclear phenotypes accompanied the insect survival response to sequential thermal shocks. Fifth instar nymphs were subjected to a single heat (35 or 40°C, 1 h) or cold (5 or 0°C, 1 h) shock and then subjected to a second shock for 12 h at 40 or 0°C, respectively, after 8, 18, 24 and 72 h at 28°C (control temperature). As with specimen survival, sequential heat and cold shocks induced changes in frequency of the mentioned nuclear phenotypes although their patterns differed. The heat shock tolerance involved decrease in apoptosis simultaneous to increase in cell survival responses. Sequential cold shocks did not involve cell/nuclear fusion and even elicited increase in necrosis with advancing time after shocks. The temperatures of 40 and 0ºC were more effective than the temperatures of 35 and 5ºC in eliciting the heat and cold shock tolerances, respectively, as shown by cytological analysis of the nuclear phenotypes. It is concluded that different sequential thermal shocks can trigger different mechanisms of cellular protection against stress in P. megistus, favoring the insect to adapt to various ecotopes.

Increased efflux of amyloid-β peptides through the blood-brain barrier by muscarinic acetylcholine receptor inhibition reduces pathological phenotypes in mouse models of brain amyloidosis.

The formation and accumulation of toxic amyloid-β peptides (Aβ) in the brain may drive the pathogenesis of Alzheimer's disease. Accordingly, disease-modifying therapies for Alzheimer's disease and related disorders could result from treatments regulating Aβ homeostasis. Examples are the inhibition of production, misfolding, and accumulation of Aβ or the enhancement of its clearance. Here we show that oral treatment with ACI-91 (Pirenzepine) dose-dependently reduced brain Aβ burden in AβPPPS1, hAβPPSL, and AβPP/PS1 transgenic mice. A possible mechanism of action of ACI-91 may occur through selective inhibition of muscarinic acetylcholine receptors (AChR) on endothelial cells of brain microvessels and enhanced Aβ peptide clearance across the blood-brain barrier. One month treatment with ACI-91 increased the clearance of intrathecally-injected Aβ in plaque-bearing mice. ACI-91 also accelerated the clearance of brain-injected Aβ in blood and peripheral tissues by favoring its urinal excretion. A single oral dose of ACI-91 reduced the half-life of interstitial Aβ peptide in pre-plaque mhAβPP/PS1d mice. By extending our studies to an in vitro model, we showed that muscarinic AChR inhibition by ACI-91 and Darifenacin augmented the capacity of differentiated endothelial monolayers for active transport of Aβ peptide. Finally, ACI-91 was found to consistently affect, in vitro and in vivo, the expression of endothelial cell genes involved in Aβ transport across the Blood Brain Brain (BBB). Thus increased Aβ clearance through the BBB may contribute to reduced Aβ burden and associated phenotypes. Inhibition of muscarinic AChR restricted to the periphery may present a therapeutic advantage as it avoids adverse central cholinergic effects.

Opposite clinical phenotypes of glucokinase disease: Description of a novel activating mutation and contiguous inactivating mutations in human glucokinase (GCK) gene.

Glucokinase is essential for glucose-stimulated insulin release from the pancreatic beta-cell, serving as glucose sensor in humans. Inactivating or activating mutations of glucokinase lead to different forms of glucokinase disease, i.e. GCK-monogenic diabetes of youth, permanent neonatal diabetes (inactivating mutations), and congenital hyperinsulinism, respectively. Here we present a novel glucokinase gene (GCK)-activating mutation (p.E442K) found in an infant with neonatal hypoglycemia (1.5 mmol/liter) and in two other family members suffering from recurrent hypoglycemic episodes in their childhood and adult life. In contrast to the severe clinical presentation in the index case, functional studies showed only a slight activation of the protein (relative activity index of 3.3). We also report on functional studies of two inactivating mutations of the GCK (p.E440G and p.S441W), contiguous to the activating one, that lead to monogenic diabetes of youth. Interestingly, adult family members carrying the GCK pE440G mutation show an unusually heterogeneous and progressive diabetic phenotype, a feature not typical of GCK-monogenic diabetes of youth. In summary, we identified a novel activating GCK mutation that although being associated with severe neonatal hypoglycemia is characterized by the mildest activation of the glucokinase enzyme of all previously reported.

Inverse relation between levels of anti-oxidized-LDL antibodies and eicosapentanoic acid (EPA).

Oxidative modification of LDL is thought to play an important role in the development of atherosclerosis. Susceptibility of LDL to peroxidation may partly depend on the compositional characteristics of the antioxidant and fatty acid content. The aim of this study was to examine the association between levels of antibodies to oxidized LDL and the various serum fatty acids in women. A total of 465 women aged 18-65 years were selected randomly from the adult population census of Pizarra, a town in southern Spain. Measurement of anti-oxidized-LDL was done by ELISA and the fatty acid composition of serum phospholipids was determined by GC. The levels of anti-oxidized-LDL antibodies were significantly related with age (r - 0.341, P < 0.001), BMI (r - 0.239, P < 0.001), waist:hip ratio (r - 0.285, P < 0.001), glucose (r - 0.208, P < 0.001), cholesterol (r - 0.243, P < 0.001), LDL-cholesterol (r - 0.185, P = 0.002), EPA (r - 0.159, P = 0.003), DHA (r - 0.121, P = 0.026), and the sum of the serum phospholipid n-3 PUFA (r - 0.141, P = 0.009). Multiple regression analysis showed that the variables that explained the behaviour of the levels of anti-oxidized-LDL antibodies were age (P < 0.001) and the serum phospholipid EPA (P < 0.001). This study showed that the fatty acid composition of serum phospholipids, and especially the percentage of EPA, was inversely related with the levels of anti-oxidized-LDL antibodies.

Behavioural responses to human skin extracts and antennal phenotypes of sylvatic first filial generation and long rearing laboratory colony Rhodnius prolixus

Chagas disease is a major public health issue and is mainly spread by Triatominae insects (Hemiptera: Reduviidae). Rhodnius prolixus is the main vector species in Northern South America. Host-seeking behaviour in R. prolixus is mediated by different compounds that are produced by and emanate from the host or microbiota on the host's skin. We tested the behavioural responses of sylvatic first filial generation (F1) and colony insects to extracts of human skin with a dual choice olfactometer. In addition, we compared the antennal phenotypes in both populations. No statistical differences were found between the two populations at the behavioural level. Both showed a preference for face and feet extracts and this effect was abolished for face extracts after treatment with an antibacterial gel. The observation of the antennal phenotype showed that there were differences between both groups in the total length, total surface area and number and density of bristles. However, the number and density of chemoreceptive sensilla (basiconic and thin and thick-walled trichoids) and the total density of sensilla did not show statistically significant differences. These results demonstrate that colony insects, which have only been fed with living hens for the last 30 years, are attracted by human skin extracts in a similar way as F1 sylvatic insects.

MicroRNA-200 family modulation in distinct breast cancer phenotypes.

The epithelial to mesenchymal transition (EMT) contributes to tumor invasion and metastasis in a variety of cancer types. In human breast cancer, gene expression studies have determined that basal-B/claudin-low and metaplastic cancers exhibit EMT-related characteristics, but the molecular mechanisms underlying this observation are unknown. As the family of miR-200 microRNAs has been shown to regulate EMT in normal tissues and cancer, here we evaluated whether the expression of the miR-200 family (miR-200f) and their epigenetic state correlate with EMT features in human breast carcinomas. We analyzed by qRT-PCR the expression of miR-200f members and various EMT-transcriptional inducers in a series of 70 breast cancers comprising an array of phenotypic subtypes: estrogen receptor positive (ER+), HER2 positive (HER2+), and triple negative (TN), including a subset of metaplastic breast carcinomas (MBCs) with sarcomatous (homologous or heterologous) differentiation. No MBCs with squamous differentiation were included. The DNA methylation status of miR-200f loci in tumor samples were inspected using Sequenom MassArray® MALDI-TOF platform. We also used two non-tumorigenic breast basal cell lines that spontaneously undergo EMT to study the modulation of miR-200f expression during EMT in vitro. We demonstrate that miR-200f is strongly decreased in MBCs compared with other cancer types. TN and HER2+ breast cancers also exhibited lower miR-200f expression than ER+ tumors. Significantly, the decreased miR-200f expression found in MBCs is accompanied by an increase in the expression levels of EMT-transcriptional inducers, and hypermethylation of the miR-200c-141 locus. Similar to tumor samples, we demonstrated that downregulation of miR-200f and hypermethylation of the miR-200c-141 locus, together with upregulation of EMT-transcriptional inducers also occur in an in vitro cellular model of spontaneous EMT. Thus, the expression and methylation status of miR-200f could be used as hypothetical biomarkers to assess the occurrence of EMT in breast cancer.

Nevirapine vs efavirenz in virologically supressed patients: Differences in lipoprotein subclasses and inflammatory biomarkers.

Background: The interaction between lipid disturbances and inflammatory markers is not well known in patients on antiretroviral therapy (ART). As nevirapine (NVP) is associated with a better lipid profile than efavirenz (EFV), we investigated the relationships between lipid profiles, lipoprotein subclasses and inflammatory biomarkers in patients with prolonged viral suppression with either NVP or EFV and no obvious clinical inflammation. Methods: 122 clinically stable HIV-infected patients with HIV-1 RNA <20 copies longer than 6 months on NNRTI therapy were studied. 72 (59%) were on EFV and 50 (41%) on NVP. Any potentially inflammatory co-morbid diseases (concurrent viral hepatitis, diabetes, hypertension, chronic liver or renal diseases), or statin treatment, were exclusion criteria. Inflammatory biomarkers included hsCRP, LpPLA2, sCD40L, IL-6, IL-8, t-PA, MCP-1, p-selectin and VCAM-1. Lipoprotein subclass measures (VLDL, LDL, IDL and HDL particle number and size) were obtained by the use of proton nuclear magnetic resonance spectroscopy. Results: 82% were male; median age 45 years. Median CD4 count 550/μL (IQR 324). Median time since HIV diagnosis 96 months (IQR 102) and accumulated time on ART 50 months (IQR 101). Patients on NVP had higher time since HIV diagnosis (126.9 [66.7] vs 91.3 [6.6] months, p=0.008) a prolonged time on ART (89.6 [54.6] vs 62.3 [52.2] months, p=0.01) and were older (47.7 vs 40.7 years, p=0.001) than those on EFV. NVP-treated patients presented increased HDL-c (55.8 [16] vs 48.8 [10.7] mg/dL, p=0.007) and apoA1 levels (153.4 [31.9] vs 141.5 [20.5] mg/dL, p=0.02), and reduced apoB/apoA1 ratio (0.68 [0.1] vs 0.61 [0.1], p=0.003) than EFV-treated patients. No differences in inflammatory markers or lipoprotein subclasses were found between NVP and EFV. In patients with extreme lipid values (less favorable: 75th percentiles of LDL, small/dense LDLp and small HDLp, or more favorable: HDL p75 and apoB/apoA1 ratio p25), no consistent differences in inflammatory biomarkers were found. Conclusions: Patients with prolonged viral suppression on NVP present significantly higher HDL and apoA1 levels and reduced apoB/apoA1 ratios than those on EFV, but no differences were found in lipoprotein particles nor inflammatory biomarkers. Relationships between lipid parameters and inflammatory biomarkers in NNRTItreated patients are complex and do not show a linear relationship in this study.

Phenotypes and endotypes of uncontrolled severe asthma: new treatments.

Severe asthma is a heterogeneous disease that affects only 5%-10% of asthmatic patients, although it accounts for a significant percentage of the consumption of health care resources. Severe asthma is characterized by the need for treatment with high doses of inhaled corticosteroids and includes several clinical and pathophysiological phenotypes. To a large extent, this heterogeneity restricts characterization of the disease and, in most cases, hinders the selection of appropriate treatment. In recent years, therefore, emphasis has been placed on improving our understanding of the various phenotypes of severe asthma and the identification of biomarkers for each of these phenotypes. Likewise, the concept of the endotype has been gaining acceptance with regard to the various subtypes of the disease, which are classified according to their unique functional or pathophysiological mechanism. This review discusses the most relevant aspects of the clinical and inflammatory phenotypes of severe asthma, including severe childhood asthma and the various endotypes of severe asthma. The main therapeutic options available for patients with uncontrolled severe asthma will also be reviewed.

Airway surface liquid volume regulation determines different airway phenotypes in liddle compared with betaENaC-overexpressing mice.

Studies in cystic fibrosis patients and mice overexpressing the epithelial Na(+) channel beta-subunit (betaENaC-Tg) suggest that raised airway Na(+) transport and airway surface liquid (ASL) depletion are central to the pathogenesis of cystic fibrosis lung disease. However, patients or mice with Liddle gain-of-function betaENaC mutations exhibit hypertension but no lung disease. To investigate this apparent paradox, we compared the airway phenotype (nasal versus tracheal) of Liddle with CFTR-null, betaENaC-Tg, and double mutant mice. In mouse nasal epithelium, the region that functionally mimics human airways, high levels of CFTR expression inhibited Liddle epithelial Nat channel (ENaC) hyperfunction. Conversely, in mouse trachea, low levels of CFTR failed to suppress Liddle ENaC hyperfunction. Indeed, Na(+) transport measured in Ussing chambers ("flooded" conditions) was raised in both Liddle and betaENaC-Tg mice. Because enhanced Na(+) transport did not correlate with lung disease in these mutant mice, measurements in tracheal cultures under physiologic "thin film" conditions and in vivo were performed. Regulation of ASL volume and ENaC-mediated Na(+) absorption were intact in Liddle but defective in betaENaC-Tg mice. We conclude that the capacity to regulate Na(+) transport and ASL volume, not absolute Na(+) transport rates in Ussing chambers, is the key physiologic function protecting airways from dehydration-induced lung disease.