44 research outputs found
The Serotonin 5-HT7Dro Receptor Is Expressed in the Brain of Drosophila, and Is Essential for Normal Courtship and Mating
The 5-HT7 receptor remains one of the less well characterized
serotonin receptors. Although it has been demonstrated to be involved in the
regulation of mood, sleep, and circadian rhythms, as well as relaxation of
vascular smooth muscles in mammals, the precise mechanisms underlying these
functions remain largely unknown. The fruit fly, Drosophila
melanogaster, is an attractive model organism to study
neuropharmacological, molecular, and behavioral processes that are largely
conserved with mammals. Drosophila express a homolog of the mammalian
5-HT7 receptor, as well as homologs for the mammalian
5-HT1A, and 5-HT2, receptors. Each fly receptor
couples to the same effector pathway as their mammalian counterpart and have
been demonstrated to mediate similar behavioral responses. Here, we report on
the expression and function of the 5-HT7Dro receptor in Drosophila.
In the larval central nervous system, expression is detected postsynaptically in
discreet cells and neuronal circuits. In the adult brain there is strong
expression in all large-field R neurons that innervate the ellipsoid body, as
well as in a small group of cells that cluster with the PDF-positive LNvs
neurons that mediate circadian activity. Following both pharmacological and
genetic approaches, we have found that 5-HT7Dro activity is essential
for normal courtship and mating behaviors in the fly, where it appears to
mediate levels of interest in both males and females. This is the first reported
evidence of direct involvement of a particular serotonin receptor subtype in
courtship and mating in the fly
Circadian pacemaker coupling by multi-peptidergic neurons in the cockroach Leucophaea maderae
Lesion and transplantation studies in the cockroach, Leucophaea maderae, have located its bilaterally symmetric circadian pacemakers necessary for driving circadian locomotor activity rhythms to the accessory medulla of the optic lobes. The accessory medulla comprises a network of peptidergic neurons, including pigment-dispersing factor (PDF)-expressing presumptive circadian pacemaker cells. At least three of the PDF-expressing neurons directly connect the two accessory medullae, apparently as a circadian coupling pathway. Here, the PDF-expressing circadian coupling pathways were examined for peptide colocalization by tracer experiments and double-label immunohistochemistry with antisera against PDF, FMRFamide, and Asn13-orcokinin. A fourth group of contralaterally projecting medulla neurons was identified, additional to the three known groups. Group one of the contralaterally projecting medulla neurons contained up to four PDF-expressing cells. Of these, three medium-sized PDF-immunoreactive neurons coexpressed FMRFamide and Asn13-orcokinin immunoreactivity. However, the contralaterally projecting largest PDF neuron showed no further peptide colocalization, as was also the case for the other large PDF-expressing medulla cells, allowing the easy identification of this cell group. Although two-thirds of all PDF-expressing medulla neurons coexpressed FMRFamide and orcokinin immunoreactivity in their somata, colocalization of PDF and FMRFamide immunoreactivity was observed in only a few termination sites. Colocalization of PDF and orcokinin immunoreactivity was never observed in any of the terminals or optic commissures. We suggest that circadian pacemaker cells employ axonal peptide sorting to phase-control physiological processes at specific times of the day
Fluctuations in active membranes
Active contributions to fluctuations are a direct consequence of metabolic
energy consumption in living cells. Such metabolic processes continuously
create active forces, which deform the membrane to control motility,
proliferation as well as homeostasis. Membrane fluctuations contain therefore
valuable information on the nature of active forces, but classical analysis of
membrane fluctuations has been primarily centered on purely thermal driving.
This chapter provides an overview of relevant experimental and theoretical
approaches to measure, analyze and model active membrane fluctuations. In the
focus of the discussion remains the intrinsic problem that the sole fluctuation
analysis may not be sufficient to separate active from thermal contributions,
since the presence of activity may modify membrane mechanical properties
themselves. By combining independent measurements of spontaneous fluctuations
and mechanical response, it is possible to directly quantify time and
energy-scales of the active contributions, allowing for a refinement of current
theoretical descriptions of active membranes.Comment: 38 pages, 9 figures, book chapte
TargetMine, an Integrated Data Warehouse for Candidate Gene Prioritisation and Target Discovery
Prioritising candidate genes for further experimental characterisation is a
non-trivial challenge in drug discovery and biomedical research in general. An
integrated approach that combines results from multiple data types is best
suited for optimal target selection. We developed TargetMine, a data warehouse
for efficient target prioritisation. TargetMine utilises the InterMine
framework, with new data models such as protein-DNA interactions integrated in a
novel way. It enables complicated searches that are difficult to perform with
existing tools and it also offers integration of custom annotations and in-house
experimental data. We proposed an objective protocol for target prioritisation
using TargetMine and set up a benchmarking procedure to evaluate its
performance. The results show that the protocol can identify known
disease-associated genes with high precision and coverage. A demonstration
version of TargetMine is available at http://targetmine.nibio.go.jp/
RANK, RANKL and osteoprotegerin in bone biology and disease
Upon the discovery of RANK, RANKL and OPG in the late 1990s, their importance in the maintenance of the skeletal structure and their dramatic role in bone disease were largely unexpected. In recent years the understanding of these proteins, in particular their regulation, has greatly increased. This review aims to bring the interested reader up to date with the latest news and views on the mechanisms controlling bone resorption in normal and pathological conditions
Alterations in Genes of the EGFR Signaling Pathway and Their Relationship to EGFR Tyrosine Kinase Inhibitor Sensitivity in Lung Cancer Cell Lines
Deregulation of EGFR signaling is common in non-small cell lung cancers (NSCLC) and this finding led to the development of tyrosine kinase inhibitors (TKIs) that are highly effective in a subset of NSCLC. Mutations of EGFR (mEGFR) and copy number gains (CNGs) of EGFR (gEGFR) and HER2 (gHER2) have been reported to predict for TKI response. Mutations in KRAS (mKRAS) are associated with primary resistance to TKIs.We investigated the relationship between mutations, CNGs and response to TKIs in a large panel of NSCLC cell lines. Genes studied were EGFR, HER2, HER3 HER4, KRAS, BRAF and PIK3CA. Mutations were detected by sequencing, while CNGs were determined by quantitative PCR (qPCR), fluorescence in situ hybridization (FISH) and array comparative genomic hybridization (aCGH). IC50 values for the TKIs gefitinib (Iressa) and erlotinib (Tarceva) were determined by MTS assay. For any of the seven genes tested, mutations (39/77, 50.6%), copy number gains (50/77, 64.9%) or either (65/77, 84.4%) were frequent in NSCLC lines. Mutations of EGFR (13%) and KRAS (24.7%) were frequent, while they were less frequent for the other genes. The three techniques for determining CNG were well correlated, and qPCR data were used for further analyses. CNGs were relatively frequent for EGFR and KRAS in adenocarcinomas. While mutations were largely mutually exclusive, CNGs were not. EGFR and KRAS mutant lines frequently demonstrated mutant allele specific imbalance i.e. the mutant form was usually in great excess compared to the wild type form. On a molar basis, sensitivity to gefitinib and erlotinib were highly correlated. Multivariate analyses led to the following results: 1. mEGFR and gEGFR and gHER2 were independent factors related to gefitinib sensitivity, in descending order of importance. 2. mKRAS was associated with increased in vitro resistance to gefitinib.Our in vitro studies confirm and extend clinical observations and demonstrate the relative importance of both EGFR mutations and CNGs and HER2 CNGs in the sensitivity to TKIs
Anti-angiogenic therapy for cancer: Current progress, unresolved questions and future directions
Tumours require a vascular supply to grow and can achieve this via the expression of pro-angiogenic growth factors, including members of the vascular endothelial growth factor (VEGF) family of ligands. Since one or more of the VEGF ligand family is overexpressed in most solid cancers, there was great optimism that inhibition of the VEGF pathway would represent an effective anti-angiogenic therapy for most tumour types. Encouragingly, VEGF pathway targeted drugs such as bevacizumab, sunitinib and aflibercept have shown activity in certain settings. However, inhibition of VEGF signalling is not effective in all cancers, prompting the need to further understand how the vasculature can be effectively targeted in tumours. Here we present a succinct review of the progress with VEGF-targeted therapy and the unresolved questions that exist in the field: including its use in different disease stages (metastatic, adjuvant, neoadjuvant), interactions with chemotherapy, duration and scheduling of therapy, potential predictive biomarkers and proposed mechanisms of resistance, including paradoxical effects such as enhanced tumour aggressiveness. In terms of future directions, we discuss the need to delineate further the complexities of tumour vascularisation if we are to develop more effective and personalised anti-angiogenic therapies. © 2014 The Author(s)