Neurotransmission is an important target for anthelmintic drugs, where receptor characteristics and response can be examined through reconstitution
ex vivo
in
Xenopus laevis
oocytes. The homomeric ...ACR-16 nicotine sensitive acetylcholine receptors (N-AChRs) of several helminth species have been characterized in this way. Our efforts to reconstitute the N-AChR from the clade III filarial parasite,
Brugia malayi
using similar conditions, initially produced no detectable response. A robust response to acetylcholine is obtained from the closely related clade III parasite
Ascaris suum
, suggesting that specific changes have occurred between
Ascaris
and
Brugia
. N-AChRs from three species intermediate between
A
.
suum
and
B
.
malayi
were characterized to provide information on the cause. Maximal response to acetylcholine did not change abruptly, consistent with a discrete event, but rather decreased progressively from
A
.
suum
through
Dracunculus medinensis
,
Gonglylonema pulchrum
and
Thelazia callipaeda
. Receptor responses to the characteristic nicotine, and other agonists were generally similar. The decrease in maximal current did correlate with a delayed time to reach larger response. Together, this suggested that the failure to reconstitute the
B
.
malayi
N-AChR was one extreme of a progressive decrease and that an issue with synthesis of the receptor in oocytes was responsible. Addition of accessory proteins EMC-6, NRA-2 and NRA-4, in addition to RIC-3, produced a small, but measurable
B
.
malayi
N-AChR response. Pharmacological properties of a chimeric
B
.
malayi
N-AChR were equivalent to the other species, confirming the receptor response remains unchanged while its production is increasingly dependent on accessory proteins. One possibility is that loss of many subunits for acetylcholine receptors from the filarial nematode genome is linked to new subunit combinations that lead to such a dependence. This novel phylogenetic approach allowed the first characterization of a
B
.
malayi
AChR
ex vivo
and in doing so, provides a framework for the successful characterization of other receptors that have yet to be reconstituted.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
BACKGROUND AND PURPOSE Several studies have demonstrated anti‐proliferative and pro‐apoptotic actions of cannabinoids on various tumours, together with their anti‐angiogenic properties. The ...non‐psychoactive cannabinoid cannabidiol (CBD) effectively inhibits the growth of different types of tumours in vitro and in vivo and down‐regulates some pro‐angiogenic signals produced by glioma cells. As its anti‐angiogenic properties have not been thoroughly investigated to date, and given its very favourable pharmacological and toxicological profile, here, we evaluated the ability of CBD to modulate tumour angiogenesis.
EXPERIMENTAL APPROACH Firstly, we evaluated the effect of CBD on human umbilical vein endothelial cell (HUVEC) proliferation and viability – through 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay and FACS analysis – and in vitro motility – both in a classical Boyden chamber test and in a wound‐healing assay. We next investigated CBD effects on different angiogenesis‐related proteins released by HUVECs, using an angiogenesis array kit and an ELISA directed at MMP2. Then we evaluated its effects on in vitro angiogenesis in treated HUVECs invading a Matrigel layer and in HUVEC spheroids embedded into collagen gels, and further characterized its effects in vivo using a Matrigel sponge model of angiogenesis in C57/BL6 mice.
KEY RESULTS CBD induced HUVEC cytostasis without inducing apoptosis, inhibited HUVEC migration, invasion and sprouting in vitro, and angiogenesis in vivo in Matrigel sponges. These effects were associated with the down‐modulation of several angiogenesis‐related molecules.
CONCLUSIONS AND IMPLICATIONS This study reveals that CBD inhibits angiogenesis by multiple mechanisms. Its dual effect on both tumour and endothelial cells supports the hypothesis that CBD has potential as an effective agent in cancer therapy.
Control and elimination of the parasitic disease schistosomiasis relies on mass administration of praziquantel. Whilst these programmes reduce infection prevalence and intensity, their impact on ...parasite transmission and evolution is poorly understood. Here we examine the genomic impact of repeated mass drug administration on Schistosoma mansoni populations with documented reduced praziquantel efficacy. We sequenced whole-genomes of 198 S. mansoni larvae from 34 Ugandan children from regions with contrasting praziquantel exposure. Parasites infecting children from Lake Victoria, a transmission hotspot, form a diverse panmictic population. A single round of treatment did not reduce this diversity with no apparent population contraction caused by long-term praziquantel use. We find evidence of positive selection acting on members of gene families previously implicated in praziquantel action, but detect no high frequency functionally impactful variants. As efforts to eliminate schistosomiasis intensify, our study provides a foundation for genomic surveillance of this major human parasite.
Haemonchus contortus is a globally distributed and economically important gastrointestinal pathogen of small ruminants and has become a key nematode model for studying anthelmintic resistance and ...other parasite-specific traits among a wider group of parasites including major human pathogens. Here, we report using PacBio long-read and OpGen and 10X Genomics long-molecule methods to generate a highly contiguous 283.4 Mbp chromosome-scale genome assembly including a resolved sex chromosome for the MHco3(ISE).N1 isolate. We show a remarkable pattern of conservation of chromosome content with Caenorhabditis elegans, but almost no conservation of gene order. Short and long-read transcriptome sequencing allowed us to define coordinated transcriptional regulation throughout the parasite's life cycle and refine our understanding of cis- and trans-splicing. Finally, we provide a comprehensive picture of chromosome-wide genetic diversity both within a single isolate and globally. These data provide a high-quality comparison for understanding the evolution and genomics of Caenorhabditis and other nematodes and extend the experimental tractability of this model parasitic nematode in understanding helminth biology, drug discovery and vaccine development, as well as important adaptive traits such as drug resistance.
Nematode glutamate-gated chloride channels (GluCls) are targets of ivermectin (IVM) and moxidectin (MOX), structurally dissimilar macrocyclic lactone (ML) anthelmintics. IVM and MOX possess different ...pharmacokinetics and efficacy profiles but are thought to have the same binding site, through which they allosterically activate GluCls, apart from the GLC-2 receptor, which is antagonized by IVM. Our goal was to determine GLC-2 sensitivity to MOX, investigate residues involved in antagonism of GLC-2, and to identify differences in receptor-level pharmacology between IVM and MOX.
Two-electrode voltage clamp electrophysiology was used to study the pharmacology of Caenorhabditis elegans GLC-2 receptors heterologously expressed in Xenopus laevis oocytes. In silico homology modeling identified Cel-GLC-2 residues Met291 and Gln292 at the IVM binding site that differ from other GluCls; we mutated these residues to those found in ML-sensitive GluCls, and those of filarial nematode GLC-2.
We discovered that MOX inhibits wild-type C. elegans GLC-2 receptors roughly 10-fold more potently than IVM, and with greater maximal inhibition of glutamate activation (MOX = 86.9 ± 2.5%; IVM = 57.8 ± 5.9%). IVM was converted into an agonist in the Met291Gln mutant, but MOX remained an antagonist. Glutamate responses were abrogated in a Met291Leu Gln292Thr double mutant (mimicking filarial nematode GLC-2), but MOX and IVM were converted into positive allosteric modulators of glutamate at this construct.
Our data provides new insights into differences in receptor-level pharmacology between IVM and MOX and identify residues responsible for ML antagonism of GLC-2.
Display omitted
•GLC-2 is antagonized by MOX more potently and with greater efficacy than IVM.•We identified receptor-level difference between IVM and MOX.•Implicates an effect of GluCl subunit composition on sensitivity to IVM and MOX.•Potential biomarker of interest for drug resistance.
The CMS experiment at the Large Hadron Collider at CERN is upgrading the photo-detection and readout system of the forward hadronic calorimeter. The phase 1 upgrade of the CMS forward calorimeter ...requires the replacement of the current photomultiplier tubes, as well as the installation of a new front-end readout system. The new photomultiplier tubes contain a thinner window as well as multi-anode readout. The front-end electronics will use the QIE10 ASIC which combines signal digitization with timing information. The major components of the upgrade as well as the current status are described in this paper.
The intricate interplay between the endothelium and immune cells has been well recognized in the context of immune responses. However, the fact that this inter-relation extends well beyond immune ...regulation is becoming increasingly recognized, with particular regards to the influence of the immune system on the essential endothelial process of angiogenesis, where the contribution of cytokines drives the angiogenic process. As angiogenesis is an important component of numerous pathological states, among these chronic inflammatory conditions and cancer, understanding the role of cytokines and chemokines in guiding new vessel formation provides key insight into novel therapeutic modalities. Here we review the actions of principal cytokines and chemokines on the angiogenic process and discuss how both can be considered potential pharmaceutical targets or pharmaceuticals themselves for modulation of angiogenesis in chronic inflammation associated with cancer, rheumatoid arthritis and other inflammatory diseases.
The main role of vitamin D is to control mineral homeostasis. However, recent studies suggested the existence of a number of extraskeletal effects. Among the latter, preclinical studies provided ...consistent data on the involvement of vitamin D in innate and adaptive immunity and autoimmunity. Molecular biology studies showed that both vitamin D receptor and vitamin D enzymatic complexes are expressed in a large number of cells and tissues unrelated to mineral homeostasis. In contrast, only a few randomized clinical trials in humans investigated the possible role of vitamin D in the prevention or treatment of immunological disorders. In this regard, low serum vitamin D levels have been reported in observational trials in human autoimmune disorders. The aim of the present paper was to review the potential implications of vitamin D in immune modulation, with special focus on thyroid autoimmune disorders.
Somatostatin was reported to inhibit Kaposi’s sarcoma (KS) cell (KS-Imm) xenografts through an antiangiogenic activity. Here, we show that somatostatin blocks growth of established KS-Imm tumors with ...the same efficacy as adriamycin, a clinically effective cytotoxic drug. Whereas KS-Imm cells do not express somatostatin receptors (SSTRs), endothelial cells express several SSTRs, in particular SSTR3. We investigated the molecular mechanisms and receptor specificity of somatostatin inhibition of angiogenesis. Somatostatin significantly inhibited angiogenesis in vivo in the matrigel sponge assay; this inhibition was mimicked by the SSTR3 agonist L-796778 and reversed by the SSTR3 antagonist BN81658, demonstrating involvement of SSTR3. In vitro experiments showed that somatostatin directly affected different endothelial cell line proliferation through a block of growth-factor-stimulated MAPK and endothelial nitric oxide (NO) synthase (eNOS) activities. BN81658 reversed somatostatin inhibition of cell proliferation, NO production, and MAPK activity, indicating that SSTR3 activation is required for the effects of somatostatin in vitro. Finally in vivo angiogenesis assays demonstrated that eNOS inhibition was a prerequisite for the antiangiogenic effects of somatostatin, because high concentrations of sodium nitroprusside, an NO donor, abolished the somatostatin effects. In conclusion, we demonstrate that somatostatin is a powerful antitumor agent in vivo that inhibits tumor angiogenesis through SSTR3-mediated inhibition of both eNOS and MAPK activities.
The idea of cancer stem cell (CSC) has recently moved to the forefront of cancer research. There is still a lack of a widespread consensus on their description and definition. ,The increasing ...literature on CSCs has compelled researchers worldwide to rewrite the natural history of cancer including those cells as principal players as well as to revise their views on tumor formation and progression. CSCs are tumor cell components that can initiate a new tumor after an apparent therapeutic eradication. A functional definition of cancer stem cell or cancer initiating cell is that of a cell which, when transplanted in a mouse model, can give rise to a tumor recapitulating the original one or even a phenotypically diverse tumor related to the tumor of origin. Since the characteristic asymmetric division of stem cells is somewhat anomalous in cancer, it might be advisable to refer to them as "stemloids". Stemness in cancer is not as much as an identity but rather a status. There is increasing evidence of the importance of the tumor and the host micro-environment in conditioning the stem cell status itself. The cancer stem cell micro-environment may be the key in the development of therapeutic strategies. We must think in terms of targeting "standard" tumor cells, cancer stem cells, and also their niche and tumor micro-environment. Here we discuss some features of cancer stem cells, and the role of the micro-environment, envisaging a choral view of cancer stem cell development and-or latency, towards development of specific therapeutic approaches. Here we propose models of replication and quiescence and the modulation by cells, genes and miRNAs. We also summarize in a table surface makers useful for the identification and isolation of CSCs.
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