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Mining of Ebola virus entry inhibitors identifies approved drugs as two-pore channel pore blockers.

Latest Publications - Tue, 11/26/2019 - 15:07
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Mining of Ebola virus entry inhibitors identifies approved drugs as two-pore channel pore blockers.

Biochim Biophys Acta Mol Cell Res. 2019 07;1866(7):1151-1161

Authors: Penny CJ, Vassileva K, Jha A, Yuan Y, Chee X, Yates E, Mazzon M, Kilpatrick BS, Muallem S, Marsh M, Rahman T, Patel S

Abstract
Two-pore channels (TPCs) are Ca2+-permeable ion channels localised to the endo-lysosomal system where they regulate trafficking of various cargoes including viruses. As a result, TPCs are emerging as important drug targets. However, their pharmacology is ill-defined. There are no approved drugs to target them. And their mechanism of ligand activation is largely unknown. Here, we identify a number of FDA-approved drugs as TPC pore blockers. Using a model of the pore of human TPC2 based on recent structures of mammalian TPCs, we virtually screened a database of ~1500 approved drugs. Because TPCs have recently emerged as novel host factors for Ebola virus entry, we reasoned that Ebola virus entry inhibitors may exert their effects through inhibition of TPCs. Cross-referencing hits from the TPC virtual screen with two recent high throughput anti-Ebola screens yielded approved drugs targeting dopamine and estrogen receptors as common hits. These compounds inhibited endogenous NAADP-evoked Ca2+ release from sea urchin egg homogenates, NAADP-mediated channel activity of TPC2 re-routed to the plasma membrane, and PI(3,5)P2-mediated channel activity of TPC2 expressed in enlarged lysosomes. Mechanistically, single channel analyses showed that the drugs reduced mean open time consistent with a direct action on the pore. Functionally, drug potency in blocking TPC2 activity correlated with inhibition of Ebola virus-like particle entry. Our results expand TPC pharmacology through the identification of approved drugs as novel blockers, support a role for TPCs in Ebola virus entry, and provide insight into the mechanisms underlying channel regulation. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.

PMID: 30408544 [PubMed - indexed for MEDLINE]

Categories: pubmed

Conserved RNA binding activity of a Yin-Yang 1 homologue in the ova of the purple sea urchin Strongylocentrotus purpuratus.

Latest Publications - Tue, 11/26/2019 - 15:07
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Conserved RNA binding activity of a Yin-Yang 1 homologue in the ova of the purple sea urchin Strongylocentrotus purpuratus.

Sci Rep. 2018 05 23;8(1):8061

Authors: Belak ZR, Ovsenek N, Eskiw CH

Abstract
Yin-Yang 1 (YY1) is a highly conserved transcription factor possessing RNA-binding activity. A putative YY1 homologue was previously identified in the developmental model organism Strongylocentrotus purpuratus (the purple sea urchin) by genomic sequencing. We identified a high degree of sequence similarity with YY1 homologues of vertebrate origin which shared 100% protein sequence identity over the DNA- and RNA-binding zinc-finger region with high similarity in the N-terminal transcriptional activation domain. SpYY1 demonstrated identical DNA- and RNA-binding characteristics between Xenopus laevis and S. purpuratus indicating that it maintains similar functional and biochemical properties across widely divergent deuterostome species. SpYY1 binds to the consensus YY1 DNA element, and also to U-rich RNA sequences. Although we detected SpYY1 RNA-binding activity in ova lysates and observed cytoplasmic localization, SpYY1 was not associated with maternal mRNA in ova. SpYY1 expressed in Xenopus oocytes was excluded from the nucleus and associated with maternally expressed cytoplasmic mRNA molecules. These data demonstrate the existence of an YY1 homologue in S. purpuratus with similar structural and biochemical features to those of the well-studied vertebrate YY1; however, the data reveal major differences in the biological role of YY1 in the regulation of maternally expressed mRNA in the two species.

PMID: 29795182 [PubMed - indexed for MEDLINE]

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Sea urchin histamine receptor 1 regulates programmed cell death in larval Strongylocentrotus purpuratus.

Latest Publications - Tue, 10/29/2019 - 14:39
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Sea urchin histamine receptor 1 regulates programmed cell death in larval Strongylocentrotus purpuratus.

Sci Rep. 2018 03 05;8(1):4002

Authors: Lutek K, Dhaliwal RS, Van Raay TJ, Heyland A

Abstract
Settlement is a rapid process in many marine invertebrate species, transitioning a planktonic larva into a benthic juvenile. In indirectly developing sea urchins, this ecological transition correlates with a morphological, developmental and physiological transition (metamorphosis) during which apoptosis is essential for the resorption and remodelling of larval and juvenile structures. While settlement is initiated by environmental cues (i.e. habitat-specific or benthic substrate cues), metamorphosis is regulated by developmental endocrine signals, such as histamine (HA), thyroid hormones (THs) and nitric oxide (NO). In the purple sea urchin, Strongylocentrotus purpuratus, we found that suH1R mRNA levels increase during larval development and peak during metamorphic competence. SuH1R positive cell clusters are prominently visible in the mouth region of sea urchin larvae, but the protein appears to be expressed at low levels throughout the larval arms and epidermis. SuH1R knock-down experiments in larval stages show that the function of suH1R is in inhibiting apoptosis. Our results therefore suggest that suH1R is regulating the metamorphic transition by inhibiting apoptosis. These results provide new insights into metamorphic mechanisms and have implications for our understanding of settlement and metamorphosis in the marine environment.

PMID: 29507306 [PubMed - indexed for MEDLINE]

Categories: pubmed

Toxigenic effects of two benthic diatoms upon grazing activity of the sea urchin: morphological, metabolomic and de novo transcriptomic analysis.

Latest Publications - Thu, 10/24/2019 - 14:35
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Toxigenic effects of two benthic diatoms upon grazing activity of the sea urchin: morphological, metabolomic and de novo transcriptomic analysis.

Sci Rep. 2018 04 04;8(1):5622

Authors: Ruocco N, Costantini S, Zupo V, Lauritano C, Caramiello D, Ianora A, Budillon A, Romano G, Nuzzo G, D'Ippolito G, Fontana A, Costantini M

Abstract
Diatoms are unicellular algae playing a key role as photosynthetic organisms in the world's ocean food webs. The chemical ecology of planktonic diatoms is well documented, but few studies have reported on the effects of benthic diatoms on their consumers, also due to difficulties in the collection, quantification and massive culturing of benthic species. Here for the first time we investigate the effects of feeding on two abundantly occurring benthic diatoms, Nanofrustulum shiloi and Cylindrotheca closterium, isolated from the leaves of the seagrass Posidonia oceanica, on the sea urchin Paracentrotus lividus. Adult P. lividus were fed for one month on diets of either one of the two diatoms and on the green alga Ulva rigida, used as a feeding control. By combining morphological, metabolomic and de novo transcriptomic approaches, we demonstrate toxigenic effect on embryos generated by females fed with these benthic diatoms. Furthermore, chemical analysis reveal the presence of polyunsaturated aldehydes only for N. shiloi, and a high production of other oxylipins (cytotoxic compounds on their grazers and on cancer cell lines) for both diatoms, including some additional peaks not correlated to the canonic oxylipins commonly observed in planktonic diatoms. These findings open new perspectives in the study of diatom secondary metabolites influencing their grazers.

PMID: 29618786 [PubMed - indexed for MEDLINE]

Categories: pubmed