The Role of Connexins and Pannexins in Mammary Gland Development and Tumorigenesis

The identification of key regulators of breast cancer onset and progression is critical for the development of targeted therapies. Connexins and pannexins are characterized by their ability to form large-pore channels and are frequently dysregulated in cancer. However, their role in breast cancer progression remains poorly understood due to a lack of in vivo models capable of assessing the proposed and opposing roles of connexins and pannexins as both tumor suppressors and/or facilitators in multiple stages of the disease. Using 2 previously uncharacterized genetically-modified mice, connexin43 (Cx43) and connexin26 (Cx26) were evaluated for their role in normal mammary gland development and function prior to using the mice to assess their linkage to breast cancer onset and progression. In addition, pannexin1 (Panx1) was evaluated for the first time in the context of mammary gland development and correlated to clinical outcomes in patients with breast cancer using in silico arrays. Using a mouse model expressing a loss-of-function Cx43 mutant it was revealed that the severity of milk ejection defects associated with Cx43 are linked to its functional status. Using a similar mouse model induced to develop primary breast cancer lesions, we identified that low functional levels of Cx43 resulted in mainly hyperplasic mammary glands that greatly increased the frequency of developing metastases to the lungs. Our assessment of mice with conditional knockdown of Cx26 during pregnancy revealed that basal levels of Cx26 were sufficient for normal alveolar development and proper lactation, but increased the susceptibility of mammary tumor onset in a chemically induced mouse model of breast cancer. Finally, genetically modified mice with systemic knockout of Panx1 identified a role for Panx1 in timely alveolar development during early lactation. In addition, Panx1 mRNA expression was correlated with worse clinical outcomes in breast cancer. Collectively, our results redefine our view of Cx43, Cx26 and Panx1 in mammary gland development; supporting a tumor suppressive role for Cx43 and Cx26, and a tumor facilitating role for Panx1 in breast cancer progression which may have implications for extending to their use as therapeutic targets

Assessing the Organizational Responsibility of Headquarters Under Differing Level of Stress

This paper describes the second in a series of full scale computer aided wargames have applied a new approach in quantitative measurement of command and control. This new approach incorporates the use of the Headquarters Effectiveness Tool, which was developed by Defense System Incorporated (DSI) of McLean, Virginia, in measuring the responses of headquarters during full-scale exercises and subsequent simulations here at the Naval Postgraduate School (NPS)

Classification of multiple electromagnetic interference events in high-voltage power plant

This paper addresses condition assessment of electrical assets contained in high voltage power plants. Our work introduces a novel analysis approach of multiple event signals related to faults, and which are measured using Electro-Magnetic Interference method. The proposed method transfers the expert’s knowledge on events presence in the signals to an intelligent system which could potentially be used for automatic EMI diagnosis. Cyclic spectrum analysis is used as feature extraction to efficiently extract the repetitive rate and the dynamic discharge level of the events, and multi-class support vector machine is adopted for their classification. This first and novel method achieved successful results which may have potential implications on developing a framework for automatic diagnosis tool of EMI events

Imaging time series for the classification of EMI discharge sources

In this work, we aim to classify a wider range of Electromagnetic Interference (EMI) discharge sources collected from new power plant sites across multiple assets. This engenders a more complex and challenging classification task. The study involves an investigation and development of new and improved feature extraction and data dimension reduction algorithms based on image processing techniques. The approach is to exploit the Gramian Angular Field technique to map the measured EMI time signals to an image, from which the significant information is extracted while removing redundancy. The image of each discharge type contains a unique fingerprint. Two feature reduction methods called the Local Binary Pattern (LBP) and the Local Phase Quantisation (LPQ) are then used within the mapped images. This provides feature vectors that can be implemented into a Random Forest (RF) classifier. The performance of a previous and the two new proposed methods, on the new database set, is compared in terms of classification accuracy, precision, recall, and F-measure. Results show that the new methods have a higher performance than the previous one, where LBP features achieve the best outcome

Classification of EMI discharge sources using time–frequency features and multi-class support vector machine

This paper introduces the first application of feature extraction and machine learning to Electromagnetic Interference (EMI) signals for discharge sources classification in high voltage power generating plants. This work presents an investigation on signals that represent different discharge sources, which are measured using EMI techniques from operating electrical machines within power plant. The analysis involves Time-Frequency image calculation of EMI signals using General Linear Chirplet Analysis (GLCT) which reveals both time and frequency varying characteristics. Histograms of uniform Local Binary Patterns (LBP) are implemented as a feature reduction and extraction technique for the classification of discharge sources using Multi-Class Support Vector Machine (MCSVM). The novelty that this paper introduces is the combination of GLCT and LBP applications to develop a new feature extraction algorithm applied to EMI signals classification. The proposed algorithm is demonstrated to be successful with excellent classification accuracy being achieved. For the first time, this work transfers expert's knowledge on EMI faults to an intelligent system which could potentially be exploited to develop an automatic condition monitoring system

Long Term Potentiation (LTP) and Long Term Depression (LTD) Cause Differential Spatial Redistribution of the Synaptic Vesicle Protein Synaptophysin in the Middle Molecular Layer of the Dentate Gyrus in Rat Hippocampus

The presynaptic modifications that accompany long-term changes in synaptic plasticity are still not fully understood. Synaptophysin is a major synaptic vesicle protein involved in neurotransmitter release. We have used quantitative electron microscopy to study synaptophysin (Syn) immunolabelling in the hippocampus of adult rats 24h after induction in vivo of long term potentiation (LTP), and long term depression (LTD). Electrodes were implanted chronically in hippocampus with stimulation at either the medial (MPP) or lateral perforant path (LPP). 24h following induction of LTP or LTD rats were rapidly perfusion fixed and hippocampal tissue processed to electron microscopy via freeze substitution method. Anti-synaptophysin post-embedding immunolabelling was performed and tissue was imaged in the middle molecular layer (MML) of the dentate gyrus. There was a significant decrease in number of Syn labelled vesicles per unit area of bouton after LTP, but not LTD. An analysis of the spatial distribution of Syn labelled synaptic vesicles showed an increase in nearest neighbour distances, more so in the LTP than the LTD group, which is consistent with the overall decrease of Syn after LTP. These data are in agreement with the suggestion that Syn is involved in clathrin-dependent and “kiss and run” endocytosis which occurs perisynaptically. Thus, an increase in release of neurotransmitter and in consequence endocytosis would be consistent with an increased active zone distance for vesicles containing Syn

Ultrastructural Distribution of the 7 Nicotinic Acetylcholine Receptor Subunit in Rat Hippocampus

Acetylcholine (ACh) is an important neurotransmitter in the mammalian brain; it is implicated in arousal, learning, and other cognitive functions. Recent studies indicate that nicotinic receptors contribute to these cholinergic effects, in addition to the established role of muscarinic receptors. In the hippocampus, where cholinergic involvement in learning and memory is particularly well documented, 7 nicotinic acetylcholine receptor subunits (7 nAChRs) are highly expressed, but their precise ultrastructural localization has not been determined. Here, we describe the results of immunogold labeling of serial ultrathin sections through stratum radiatum of area CA1 in the rat. Using both anti-7 nAChR immunolabeling and -bungarotoxin binding, we find that 7 nAChRs are present at nearly all synapses in CA1 stratum radiatum, with immunolabeling present at both presynaptic and postsynaptic elements. Morphological considerations and double immunolabeling indicate that GABAergic as well as glutamatergic synapses bear 7 nAChRs, at densities approaching those observed for glutamate receptors in CA1 stratum radiatum. Postsynaptically, 7 nAChRs often are distributed at dendritic spines in a perisynaptic annulus. In the postsynaptic cytoplasm, immunolabeling is associated with spine apparatus and other membranous structures, suggesting that 7 nAChRs may undergo dynamic regulation, with insertion into the synapse and subsequent internalization. The widespread and substantial expression of 7 nAChRs at synapses in the hippocampus is consistent with an important role in mediating and/or modulating synaptic transmission, plasticity, and neurodegeneration

Lymphatic expression of CLEVER-1 in breast cancer and its relationship with lymph node metastasis

BACKGROUND Mechanisms regulating breast cancer lymph node metastasis are unclear. Staining of CLEVER-1 (common lymphatic endothelial and vascular endothelial receptor-1) in human breast tumors was used, along with in vitro techniques, to assess involvement in the metastatic process. METHODS 148 sections of primary invasive breast cancers, with 10 yr follow-up, were stained with anti-CLEVER-1. Leukocyte infiltration was assessed, along with involvement of specific subpopulations by staining with CD83 (mature dendritic cells, mDC), CD209 (immature DC, iDC) and CD68 (macrophage, Mϕ). In vitro expression of CLEVER-1 on lymphatic (LEC) and blood endothelial cells (BEC) was examined by flow cytometry. RESULTS In vitro results showed that although both endothelial cell types express CLEVER-1, surface expression was only evident on LEC. In tumour sections CLEVER-1 was expressed in blood vessels (BV, 61.4% of samples), lymphatic vessels (LV, 18.2% of samples) and in Mϕ/DCs (82.4% of samples). However, only CLEVER-1 expression in LV was associated with LN metastasis (p = 0.027) and with Mϕ indices (p = 0.021). Although LV CLEVER-1 was associated with LN positivity there was no significant correlation with recurrence or overall survival, BV CLEVER-1 expression was, however, associated with increased risk of recurrence (p = 0.049). The density of inflammatory infiltrate correlated with CLEVER-1 expression in BV (p < 0.001) and LV (p = 0.004). CONCLUSIONS The associations between CLEVER-1 expression on endothelial vessels and macrophage/leukocyte infiltration is suggestive of its regulation by inflammatory conditions in breast cancer, most likely by macrophage-associated cytokines. Its upregulation on LV, related surface expression, and association with LN metastasis suggest that it may be an important mediator of tumor cell metastasis to LN

Effects of oxytocin-family peptides and substance P on locomotor activity and filial preferences in visually naïve chicks.

Nonapeptides from the vasopressin/oxytocin family have been implicated in a wide variety of social behaviors across vertebrates. Experimental manipulations that alter nonapeptide levels or receptor function in the brain have provided evidence for understanding how nonapeptides influence responses to social stimuli in adults. While behaviors in adults have been extensively studied, much less in known about roles of nonapeptides in early life and the development of affiliative social behaviors. We examined an experience-independent preference (social predisposition) that is present at hatching and is characterized by the tendency of visually naïve chicks (Gallus gallus) to prefer to approach a stuffed-hen stimulus over a control stimulus in a choice test. Among chicks that show the social predisposition preference, bilateral intracranial mesotocin injections resulted in higher mean hen preference scores compared to saline-injected controls. Equimolar doses of mesotocin and vasotocin injections had different effects on locomotor activity: vasotocin, but not mesotocin, resulted in hypoactivity. We also tested whether intraperitoneal substance P had an effect on hen preference scores because previous research has proposed that vasotocin effects on social approach are mediated by peripheral release of substance P, but found no significant effect. All together, our data suggests that mesotocin signaling may be important for social predispositions and can potentially enhance the perceived salience of social stimuli soon after hatching. Specifically, mesotocin release and signaling in the brain may regulate the ability to recognize naturalistic stimuli and/or to act on the motivation to approach naturalistic stimuli

Genome-Wide Association Study for Maize Leaf Cuticular Conductance Identifies Candidate Genes Involved in the Regulation of Cuticle Development.

The cuticle, a hydrophobic layer of cutin and waxes synthesized by plant epidermal cells, is the major barrier to water loss when stomata are closed at night and under water-limited conditions. Elucidating the genetic architecture of natural variation for leaf cuticular conductance (g c) is important for identifying genes relevant to improving crop productivity in drought-prone environments. To this end, we conducted a genome-wide association study of g c of adult leaves in a maize inbred association panel that was evaluated in four environments (Maricopa, AZ, and San Diego, CA, in 2016 and 2017). Five genomic regions significantly associated with g c were resolved to seven plausible candidate genes (ISTL1, two SEC14 homologs, cyclase-associated protein, a CER7 homolog, GDSL lipase, and β-D-XYLOSIDASE 4). These candidates are potentially involved in cuticle biosynthesis, trafficking and deposition of cuticle lipids, cutin polymerization, and cell wall modification. Laser microdissection RNA sequencing revealed that all these candidate genes, with the exception of the CER7 homolog, were expressed in the zone of the expanding adult maize leaf where cuticle maturation occurs. With direct application to genetic improvement, moderately high average predictive abilities were observed for whole-genome prediction of g c in locations (0.46 and 0.45) and across all environments (0.52). The findings of this study provide novel insights into the genetic control of g c and have the potential to help breeders more effectively develop drought-tolerant maize for target environments