Metabolic signatures of lung cancer in biofluids: NMR-based metabonomics of blood plasma

In this work, the variations in the metabolic profile of blood plasma from lung cancer patients and healthy controls were investigated through NMR-based metabonomics, to assess the potential of this approach for lung cancer screening and diagnosis. PLS-DA modeling of CPMG spectra from plasma, subjected to Monte Carlo Cross Validation, allowed cancer patients to be discriminated from controls with sensitivity and specificity levels of about 90%. Relatively lower HDL and higher VLDL + LDL in the patients' plasma, together with increased lactate and pyruvate and decreased levels of glucose, citrate, formate, acetate, several amino acids (alanine, glutamine, histidine, tyrosine, valine), and methanol, could be detected. These changes were found to be present at initial disease stages and could be related to known cancer biochemical hallmarks, such as enhanced glycolysis, glutaminolysis, and gluconeogenesis, together with suppressed Krebs cycle and reduced lipid catabolism, thus supporting the hypothesis of a systemic metabolic signature for lung cancer. Despite the possible confounding influence of age, smoking habits, and other uncontrolled factors, these results indicate that NMR-based metabonomics of blood plasma can be useful as a screening tool to identify suspicious cases for subsequent, more specific radiological tests, thus contributing to improved disease management.     

Association of genetic variants in complement factor H and factor H-related genes with systemic lupus erythematosus susceptibility

Systemic lupus erythematosus (SLE), a complex polygenic autoimmune disease, is associated with increased complement activation. Variants of genes encoding complement regulator factor H (CFH) and five CFH-related proteins (CFHR1-CFHR5) within the chromosome 1q32 locus linked to SLE, have been associated with multiple human diseases and may contribute to dysregulated complement activation predisposing to SLE. We assessed 60 SNPs covering the CFH-CFHRs region for association with SLE in 15,864 case-control subjects derived from four ethnic groups. Significant allelic associations with SLE were detected in European Americans (EA) and African Americans (AA), which could be attributed to an intronic CFH SNP (rs6677604, in intron 11, P _meta = 6.6×10⁻⁸, OR = 1.18) and an intergenic SNP between CFHR1 and CFHR4 (rs16840639, P _meta = 2.9×10⁻⁷, OR = 1.17) rather than to previously identified disease-associated CFH exonic SNPs, including I62V, Y402H, A474A, and D936E. In addition, allelic association of rs6677604 with SLE was subsequently confirmed in Asians (AS). Haplotype analysis revealed that the underlying causal variant, tagged by rs6677604 and rs16840639, was localized to a ∼146 kb block extending from intron 9 of CFH to downstream of CFHR1. Within this block, the deletion of CFHR3 and CFHR1 (CFHR3-1Δ), a likely causal variant measured using multiplex ligation-dependent probe amplification, was tagged by rs6677604 in EA and AS and rs16840639 in AA, respectively. Deduced from genotypic associations of tag SNPs in EA, AA, and AS, homozygous deletion of CFHR3-1Δ (P _meta = 3.2×10⁻⁷, OR = 1.47) conferred a higher risk of SLE than heterozygous deletion (P _meta = 3.5×10⁻⁴, OR = 1.14). These results suggested that the CFHR3-1Δ deletion within the SLE-associated block, but not the previously described exonic SNPs of CFH, might contribute to the development of SLE in EA, AA, and AS, providing new insights into the role of complement regulators in the pathogenesis of SLE.     

Physiological level of norepinephrine increases adenine nucleotides hydrolysis in rat blood serum

Extracellular adenosine 5′-triphosphate (ATP) and its breakdown products, adenosine 5′-diphosphate (ADP) and adenosine, have significant effects on a variety of biological processes. NTPDase enzymes, responsible for adenine nucleotides hydrolysis, are considered the major regulators of purinergic signaling in the blood. Previous work by our group demonstrated that ATP and ADP hydrolysis in rat blood serum are higher during the dark (activity) phase compared to the light (rest) phase. In nocturnal animals (e.g., rats), important physiological changes occur during the dark phase, such as increased circulating levels of melatonin, corticosterone, and norepinephrine (NE). This study investigated the physiological effects, in vivo and in vitro, of melatonin, dexamethasone, and NE upon nucleotides hydrolysis in rat blood serum. For in vivo experiments, the animals received a single injection of saline (control), melatonin (0.05 mg/kg), dexamethasone (0.1 mg/kg), or NE (0.03 mg/kg). For in vitro experiments, melatonin (1.0 nM), dexamethasone (1.0 μM), or NE (1.0 nM) was added directly to the reaction medium with blood serum before starting the enzyme assay. The results demonstrated that ATP and ADP hydrolysis in both in vitro and in vivo experiments were significantly higher with NE treatment compared to control (in vitro: ATP = 36.63%, ADP = 22.43%, P < 0.05; in vivo: ATP = 44.1%, ADP = 37.28%, P < 0.001). No significant differences in adenine nucleotides hydrolysis were observed with melatonin and dexamethasone treatments. This study suggests a modulatory role of NE in the nucleotidases pathway, decreasing extracellular ATP and ADP, and suggests that NE might modulate its own release by increasing the activities of soluble nucleotidases.     

Three groups of interneurons account for nearly 100% of neocortical GABAergic neurons

An understanding of the diversity of cortical GABAergic interneurons is critical to understand the function of the cerebral cortex. Recent data suggest that neurons expressing three markers, the Ca2+-binding protein parvalbumin (PV), the neuropeptide somatostatin (SST), and the ionotropic serotonin receptor 5HT3a (5HT3aR) account for nearly 100% of neocortical interneurons. Interneurons expressing each of these markers have a different embryological origin. Each group includes several types of interneurons that differ in morphological and electrophysiological properties and likely have different functions in the cortical circuit. The PV group accounts for ～40% of GABAergic neurons and includes fast spiking basket cells and chandelier cells. The SST group, which represents ～30% of GABAergic neurons, includes the Martinotti cells and a set of neurons that specifically target layerIV. The 5HT3aR group, which also accounts for ～30% of the total interneuronal population, is heterogeneous and includes all of the neurons that express the neuropeptide VIP, as well as an equally numerous subgroup of neurons that do not express VIP and includes neurogliaform cells. The universal modulation of these neurons by serotonin and acetylcholine via ionotropic receptors suggests that they might be involved in shaping cortical circuits during specific brain states and behavioral contexts.     

Tobacco smoke mediated induction of sinonasal microbial biofilms

Cigarette smokers and those exposed to second hand smoke are more susceptible to life threatening infection than non-smokers. While much is known about the devastating effect tobacco exposure has on the human body, less is known about the effect of tobacco smoke on the commensal and commonly found pathogenic bacteria of the human respiratory tract, or human respiratory tract microbiome. Chronic rhinosinusitis (CRS) is a common medical complaint, affecting 16% of the US population with an estimated aggregated cost of $6 billion annually. Epidemiologic studies demonstrate a correlation between tobacco smoke exposure and rhinosinusitis. Although a common cause of CRS has not been defined, bacterial presence within the nasal and paranasal sinuses is assumed to be contributory. Here we demonstrate that repetitive tobacco smoke exposure induces biofilm formation in a diverse set of bacteria isolated from the sinonasal cavities of patients with CRS. Additionally, bacteria isolated from patients with tobacco smoke exposure demonstrate robust in vitro biofilm formation when challenged with tobacco smoke compared to those isolated from smoke naïve patients. Lastly, bacteria from smoke exposed patients can revert to a non-biofilm phenotype when grown in the absence of tobacco smoke. These observations support the hypothesis that tobacco exposure induces sinonasal biofilm formation, thereby contributing to the conversion of a transient and medically treatable infection to a persistent and therapeutically recalcitrant condition.     

Irrelevant features of a stimulus can either facilitate or disrupt performance in a working memory task: the role of fluid intelligence

It has been shown that fluid intelligence (gf) is fundamental to overcome interference due to information of a previously encoded item along a task-relevant domain. However, the biasing effect of task-irrelevant dimensions is still unclear as well as its relation with gf. The present study aimed at clarifying these issues. Gf was assessed in 60 healthy subjects. In a different session, the same subjects performed two versions (letter-detection and spatial) of a three-back working memory task with a set of physically identical stimuli (letters) presented at different locations on the screen. In the letter-detection task, volunteers were asked to match stimuli on the basis of their identity whereas, in the spatial task, they were required to match items on their locations. Cross-domain bias was manipulated by pseudorandomly inserting a match between the current and the three back items on the irrelevant domain. Our findings showed that a task-irrelevant feature of a salient stimulus can actually bias the ongoing performance. We revealed that, at trials in which the current and the three-back items matched on the irrelevant domain, group accuracy was lower (interference). On the other hand, at trials in which the two items matched on both the relevant and irrelevant domains, the group showed an enhancement of the performance (facilitation). Furthermore, we demonstrated that individual differences in fluid intelligence covaries with the ability to override cross-domain interference in that higher gf subjects showed better performance at interference trials than low gf subjects. Altogether, our findings suggest that stimulus features irrelevant to the task can affect cognitive performance along the relevant domain and that gf plays an important role in protecting relevant memory contents from the hampering effect of such a bias.     

Boosting of synaptic potentials and spine Ca transients by the peptide toxin SNX-482 requires alpha-1E-encoded voltage-gated Ca channels

The majority of glutamatergic synapses formed onto principal neurons of the mammalian central nervous system are associated with dendritic spines. Spines are tiny protuberances that house the proteins that mediate the response of the postsynaptic cell to the presynaptic release of glutamate. Postsynaptic signals are regulated by an ion channel signaling cascade that is active in individual dendritic spines and involves voltage-gated calcium (Ca) channels, small conductance (SK)-type Ca-activated potassium channels, and NMDA-type glutamate receptors. Pharmacological studies using the toxin SNX-482 indicated that the voltage-gated Ca channels that signal within spines to open SK channels belong to the class Ca(V)2.3, which is encoded by the Alpha-1E pore-forming subunit. In order to specifically test this conclusion, we examined the effects of SNX-482 on synaptic signals in acute hippocampal slices from knock-out mice lacking the Alpha-1E gene. We find that in these mice, application of SNX-482 has no effect on glutamate-uncaging evoked synaptic potentials and Ca influx, indicating that that SNX-482 indeed acts via the Alpha-1E-encoded Ca(V)2.3 channel.     

Re-structuring of marine communities exposed to environmental change: a global study on the interactive effects of species and functional richness

Species richness is the most commonly used but controversial biodiversity metric in studies on aspects of community stability such as structural composition or productivity. The apparent ambiguity of theoretical and experimental findings may in part be due to experimental shortcomings and/or heterogeneity of scales and methods in earlier studies. This has led to an urgent call for improved and more realistic experiments. In a series of experiments replicated at a global scale we translocated several hundred marine hard bottom communities to new environments simulating a rapid but moderate environmental change. Subsequently, we measured their rate of compositional change (re-structuring) which in the great majority of cases represented a compositional convergence towards local communities. Re-structuring is driven by mortality of community components (original species) and establishment of new species in the changed environmental context. The rate of this re-structuring was then related to various system properties. We show that availability of free substratum relates negatively while taxon richness relates positively to structural persistence (i.e., no or slow re-structuring). Thus, when faced with environmental change, taxon-rich communities retain their original composition longer than taxon-poor communities. The effect of taxon richness, however, interacts with another aspect of diversity, functional richness. Indeed, taxon richness relates positively to persistence in functionally depauperate communities, but not in functionally diverse communities. The interaction between taxonomic and functional diversity with regard to the behaviour of communities exposed to environmental stress may help understand some of the seemingly contrasting findings of past research.     

Metabolon disruption: a mechanism that regulates bicarbonate transport

Carbonic anhydrases (CA) catalyze the reversible conversion of CO2 to HCO3-. Some bicarbonate transporters bind CA, forming a complex called a transport metabolon, to maximize the coupled catalytic/transport flux. SLC26A6, a plasma membrane Cl-/HCO3- exchanger with a suggested role in pancreatic HCO3- secretion, was found to bind the cytoplasmic enzyme CAII. Mutation of the identified CAII binding (CAB) site greatly reduced SLC26A6 activity, demonstrating the importance of the interaction. Regulation of SLC26A6 bicarbonate transport by protein kinase C (PKC) was investigated. Angiotensin II (AngII), which activates PKC, decreased Cl-/HCO3- exchange in cells coexpressing SLC26A6 and AT1a-AngII receptor. Activation of PKC reduced SLC26A6/CAII association in immunoprecipitates. Similarly, PKC activation displaced CAII from the plasma membrane, as monitored by immunofluorescence. Finally, mutation of a PKC site adjacent to the SLC26A6 CAB site rendered the transporter unresponsive to PKC. PKC therefore reduces CAII/SLC26A6 interaction, reducing bicarbonate transport rate. Taken together, our data support a mechanism for acute regulation of membrane transport: metabolon disruption.     

Dried blood spots as a practical and inexpensive source for human immunodeficiency virus and hepatitis C virus surveillance

Passive surveillance of infectious diseases with a high percentage of asymptomatic cases or long incubation periods, such as acquired immunodeficiency syndrome (AIDS), does not reflect the current transmission dynamics. Thus, a multi-strategic surveillance, such as the human immunodeficiency virus (HIV) sentinel surveillance proposed by the World Health Organization (WHO), is necessary. The Brazilian HIV sentinel surveillance was started in May 1992 with this purpose. The objectives of this study were to evaluate the feasibility and costs of HIV and hepatitis C virus (HCV) surveillance using dried blood spots (DBS) collected for neonatal screening of metabolic diseases in the state of Minas Gerais, Brazil. This was accomplished through the comparison of HIV and HCV seroprevalence with previous Brazilian studies. From December 2001 to June 2002, 24,905 newborns were tested for HIV and 4211 for HCV. HIV seroprevalence was 0.25% and the 95% confidence interval (CI) was 0.18, 0.31%; and HCV seroprevalence was 0.71% and the 95% CI was 0.46, 0.97%. These numbers are similar to previous Brazilian studies. Cost in this study was approximately USD 3.10 per sample, which was roughly one third of the cost of the same exam at the Brazilian HIV sentinel surveillance. We conclude that it is possible and more cost-effective to use DBS for infectious diseases surveillance, albeit it is still necessary to compare these results with the usual sentinel methodology in a concomitant trial.