616 research outputs found

    Circumventricular organ apelin receptor knockdown decreases blood pressure and sympathetic drive responses in the spontaneously hypertensive rat

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    The central site(s) mediating the cardiovascular actions of the apelin-apelin receptor (APJ) system remains a major question. We hypothesized that the sensory circumventricular organs (CVOs), interfacing between the circulation and deeper brain structures, are sites where circulating apelin acts as a signal in the central nervous system to decrease blood pressure (BP). We show that APJ gene (aplnr) expression was elevated in the CVOs of spontaneously hypertensive rats (SHRs) compared to normotensive Wistar Kyoto (WKY) controls, and that there was a greater mean arterial BP (MABP) decrease following microinjection of [Pyr(1)]apelin-13 to the CVOs of SHRs compared to WKY rats. Lentiviral APJ-specific-shRNA (LV-APJ-shRNA) was used to knockdown aplnr expression, both collectively in three CVOs and discretely in individual CVOs, of rats implanted with radiotelemeters to measure arterial pressure. LV-APJ-shRNA-injection decreased aplnr expression in the CVOs and abolished MABP responses to microinjection of [Pyr(1)]apelin-13. Chronic knockdown of aplnr in any of the CVOs, collectively or individually, did not affect basal MABP in SHR or WKY rats. Moreover, knockdown of aplnr in any of the CVOs individually did not affect the depressor response to systemic [Pyr(1)]apelin-13. By contrast, multiple knockdown of aplnr in the three CVOs reduced acute cardiovascular responses to peripheral [Pyr(1)]apelin-13 administration in SHR but not WKY rats. These results suggest that endogenous APJ activity in the CVOs has no effect on basal BP but that functional APJ in the CVOs is required for an intact cardiovascular response to peripherally administered apelin in the SHR

    Increased apelin receptor gene expression in the subfornical organ of spontaneously hypertensive rats.

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    The vascular organ of the lamina terminalis, subfornical organ (SFO), and area postrema comprise the sensory circumventricular organs (CVO) which are central structures that lie outside the blood brain barrier and are thought to provide an interface between peripherally circulating signals and the brain through their projections to central autonomic structures. The SFO expresses mRNA for the G protein-coupled apelin receptor (APJ, gene name aplnr) and exogenous microinjection of the neuropeptide apelin (apln) to the SFO elicits a depressor effect. Here we investigated the expression and cellular distribution of aplnr, apln and the recently described ligand apela (apela) in the CVOs and investigated whether differences in the levels of expression of apelinergic gene transcripts in these regions might underlie the chronic elevated blood pressure seen in hypertension. We carried out multiplex in situ hybridization histochemistry on CVO tissue sections from spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto (WKY) controls. Confocal immunofluorescent images indicated strong aplnr expression, with lower levels of apln and modest apela expression, in the CVOs of both WKY rats and SHRs, in both neurons and glia. The expression level of aplnr transcripts was increased in the SFO of SHRs compared to WKY rats. Our data may highlight a potential dysfunction in the communication between CVOs and downstream signalling pathways in SHRs, which may contribute to its different phenotype/s

    Dependence on Mincle and Dectin-2 Varies With Multiple Candida Species During Systemic Infection

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    FUNDING SO was supported by a Sir Henry Dale Fellowship jointly funded by the Wellcome Trust and the Royal Society (Grant No. 099953/Z/12/Z) and by a Wellcome Trust Cross-Disciplinary Award. NG acknowledges Wellcome Trust support of a Senior Investigator (101873/Z/13/Z), Collaborative (200208/A/15/Z) and Strategic Awards (097377/Z11/Z) and the MRC Centre for Medical Mycology (MR/N006364/2). PT was funded by a Wellcome Trust Investigator Award (107964/Z/15/Z) and the UK Dementia Research Institute. ACKNOWLEDGMENTS We wish to acknowledge the NIH-sponsored Mutant Mouse Regional Resource Center (MMRRC) National System as the source of genetically altered mice (C57BL/6-Clec4et m1. 1C fg /Mmucd 031936-UCD) for use in this study. The mice were produced and deposited to the MMRRC by the Consortium for Functional Glycomics supported by the National Institute of General Medical Sciences (GM62116). We also thank the Microscopy and Histology Core Facility at the University of Aberdeen for expert assistance with TEM.Peer reviewedPublisher PD

    Limitation of Algal Growth by Iron Deficiency in the Australian Subantarctic Region

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    In March 1998 we measured iron in the upper water column and conducted iron- and nutrient-enrichment bottle-incubation experiments in the open-ocean Subantarctic region southwest of Tasmania, Australia. In the Subtropical Convergence Zone (∼42°S, 142°E), silicic acid concentrations were low (\u3c 1.5μM) in the upper water column, whereas pronounced vertical gradients in dissolved iron concentration (0.12-0.84 nM) were observed., presumably reflecting the interleaving of Subtropical and Subantarctic waters, and mineral aerosol input. Results of a bottle-incubation experiment performed at this location indicate that phytoplankton growth rates were limited by iron deficiency within the iron-poor layer of the euphotic zone. In the Subantarctic water mass (∼46.8°S, 142°E), low concentrations of dissolved iron (0.05-0.11nM) and silicic acid (\u3c 1μM) were measured throughout the upper water column, and our experimental results indicate that algal growth was limited by iron deficiency. These observations suggest that availability of dissolved iron is a primary factor limiting phytoplankton growth over much of the Subantarctic Southern Ocean in the late summer and autumn

    Measuring societal awareness of the rural agrarian landscape: indicators and scale issues

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    The work presented in this report is part of the effort to define the landscape state and diversity indicator in the frame of COM (2006) 508 “Development of agri-environmental indicators for monitoring the integration of environmental concerns into the common agricultural policy”. The Communication classifies the indicators according to their level of development, which, for the landscape indicator is “in need of substantial improvements in order to become fully operational”. For this reason a full re-definition of the indicator has been carried out, following the initial proposal presented in the frame of the IRENA operation (“Indicator Reporting on the Integration of Environmental Concerns into Agricultural Policy”). The new proposal for the landscape state and diversity indicator is structured in three components: the first concerns the degree of naturalness, the second landscape structure, the third the societal appreciation of the rural landscape. While the first two components rely on a strong bulk of existing literature, the development of the methodology has made evident the need for further analysis of the third component, which is based on a newly proposed top-down approach. This report presents an in-depth analysis of such component of the indicator, and the effort to include a social dimension in large scale landscape assessment.JRC.H.4-Monitoring Agricultural Resource

    The protective effect of inflammatory monocytes during systemic C. albicans infection is dependent on collaboration between C-type lectin-like receptors

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    Acknowledgments The authors wish to acknowledge the NIH-sponsored Mutant Mouse Regional Resource Center (MMRRC) National System as the source of genetically-altered mice (C57BL/6-Clec4etm1.1Cfg/Mmucd 031936-UCD) for use in this study. The mice were produced and deposited to the MMRRC by the Consortium for Functional Glycomics supported by the National Institute of General Medical Sciences (GM62116). We would like to thank Catherine Neiseryan and Ann Kift-Morgan for cell sorting. We would like to thank Wales Gene Park for providing computer resources that assisted this research. Funding: SJO was funded by a Sir Henry Dale Fellowship jointly funded by the Wellcome Trust and the Royal Society (Grant Number 099953/Z/12/Z) and by a Wellcome Trust ISSF Cross-Disciplinary Award. LCD is supported by a Henry Wellcome Trust Postdoctoral Fellowship (103973/Z/14/Z). CL is supported by a Kidney Research UK/MedImmune Joint Fellowship Award (PDF_006_20151127). GDB is funded by a Wellcome Trust Investigator Award (102705) and the MRC Centre for Medical Mycology and the University of Aberdeen (MR/N006364/1). IRH is supported by a Wellcome Trust Senior Research Fellowship (207503/Z/17/Z). PRT is supported by a Wellcome Trust Investigator Award (107964/Z/15/Z) and the UK Dementia Research Institute. Funding URLs: https://wellcome.ac.uk/ https://royalsociety.org/ https://www.kidneyresearchuk.org/ https://mrc.ukri.org/ https://ukdri.ac.uk/ The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Data Availability: All relevant data apart from RNAseq files are within the manuscript and its Supporting Information files. RNAseq data files are available from ArrayExpress (https://www.ebi.ac.uk/arrayexpress/), (accession number E-MTAB-8030).Peer reviewedPublisher PD
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