1
|
Padamsey Z, McGuinness L, Emptage NJ. Inhibition of lysosomal Ca 2+ signalling disrupts dendritic spine structure and impairs wound healing in neurons. Commun Integr Biol 2017; 10:e1344802. [PMID: 29259727 PMCID: PMC5731510 DOI: 10.1080/19420889.2017.1344802] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 06/14/2017] [Accepted: 06/15/2017] [Indexed: 11/21/2022] Open
Abstract
A growing body of evidence suggests that lysosomes, which have traditionally been regarded as degradative organelles, can function as Ca2+ stores, regulated by the second messenger nicotinic acid adenine dinucleotide phosphate (NAADP). We previously demonstrated that in hippocampal pyramidal neurons, activity-dependent Ca2+ release from these stores triggers fusion of the lysosome with the plasma membrane. We found that the physiological role of this Ca2+-dependent fusion was to maintain the long-term structural enlargement of dendritic spines induced by synaptic activity. Here, we examined the pathophysiological consequences of lysosomal dysfunction in hippocampal pyramidal neurons by chronically inhibiting lysosomal Ca2+ signalling using the NAADP antagonist, NED-19. We found that within just 20 hours, inhibition of lysosomal function led to a profound intracellular accumulation of lysosomal membrane. This was accompanied by a significant change in dendritic spine structure, which included a lengthening of dendritic spines, an increase in the number of filipodia, and an overall decrease in spine number. Inhibition of lysosomal function also inhibited wound healing in neurons by preventing lysosomal fusion with the plasma membrane. Neurons were therefore more susceptible to injury. Our findings suggest that dysfunction in lysosomal Ca2+ signalling and lysosomal fusion with the plasma membrane may contribute to the loss of dendritic spines and neurons seen in neurological disorders, such as Niemann-Pick disease type C1, in which lysosomal function is impaired.
Collapse
Affiliation(s)
- Zahid Padamsey
- Department of Pharmacology, University of Oxford, Oxford, UK
| | | | - Nigel J Emptage
- Department of Pharmacology, University of Oxford, Oxford, UK
| |
Collapse
|
2
|
Padamsey Z, McGuinness L, Bardo SJ, Reinhart M, Tong R, Hedegaard A, Hart ML, Emptage NJ. Activity-Dependent Exocytosis of Lysosomes Regulates the Structural Plasticity of Dendritic Spines. Neuron 2016; 93:132-146. [PMID: 27989455 PMCID: PMC5222721 DOI: 10.1016/j.neuron.2016.11.013] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 09/02/2016] [Accepted: 10/31/2016] [Indexed: 11/28/2022]
Abstract
Lysosomes have traditionally been viewed as degradative organelles, although a growing body of evidence suggests that they can function as Ca2+ stores. Here we examined the function of these stores in hippocampal pyramidal neurons. We found that back-propagating action potentials (bpAPs) could elicit Ca2+ release from lysosomes in the dendrites. This Ca2+ release triggered the fusion of lysosomes with the plasma membrane, resulting in the release of Cathepsin B. Cathepsin B increased the activity of matrix metalloproteinase 9 (MMP-9), an enzyme involved in extracellular matrix (ECM) remodelling and synaptic plasticity. Inhibition of either lysosomal Ca2+ signaling or Cathepsin B release prevented the maintenance of dendritic spine growth induced by Hebbian activity. This impairment could be rescued by exogenous application of active MMP-9. Our findings suggest that activity-dependent exocytosis of Cathepsin B from lysosomes regulates the long-term structural plasticity of dendritic spines by triggering MMP-9 activation and ECM remodelling. Back-propagating action potentials induce Ca2+ release from lysosomes in neurons Lysosomal Ca2+ release triggers exocytosis of the lysosomal protease Cathepsin B Cathepsin B maintains activity-dependent dendritic spine growth by activating MMP-9
Collapse
Affiliation(s)
- Zahid Padamsey
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Lindsay McGuinness
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Scott J Bardo
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Marcia Reinhart
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Rudi Tong
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Anne Hedegaard
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Michael L Hart
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Nigel J Emptage
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
| |
Collapse
|
3
|
Lovchinsky I, Sushkov AO, Urbach E, de Leon NP, Choi S, De Greve K, Evans R, Gertner R, Bersin E, Müller C, McGuinness L, Jelezko F, Walsworth RL, Park H, Lukin MD. Nuclear magnetic resonance detection and spectroscopy of single proteins using quantum logic. Science 2016; 351:836-41. [DOI: 10.1126/science.aad8022] [Citation(s) in RCA: 301] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 01/21/2016] [Indexed: 02/05/2023]
Affiliation(s)
- I. Lovchinsky
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - A. O. Sushkov
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - E. Urbach
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - N. P. de Leon
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - S. Choi
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - K. De Greve
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - R. Evans
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - R. Gertner
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - E. Bersin
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - C. Müller
- Institute for Quantum Optics and Center for Integrated Quantum Science and Technology (IQST), Ulm University, D-89081, Ulm, Germany
| | - L. McGuinness
- Institute for Quantum Optics and Center for Integrated Quantum Science and Technology (IQST), Ulm University, D-89081, Ulm, Germany
| | - F. Jelezko
- Institute for Quantum Optics and Center for Integrated Quantum Science and Technology (IQST), Ulm University, D-89081, Ulm, Germany
| | - R. L. Walsworth
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
- Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA
- Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - H. Park
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
- Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
- Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA
| | - M. D. Lukin
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| |
Collapse
|
4
|
Andonov A, Lin L, McGuinness L, Krajden M. Distribution of Hepatitis C virus genotypes among newly acquired HCV infections in British Columbia (2000-2013). Can Commun Dis Rep 2014; 40:437-443. [PMID: 29769875 PMCID: PMC5864462 DOI: 10.14745/ccdr.v40i19a03] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Characterization of newly acquired Hepatitis C virus (HCV) infections is important in order to understand the epidemiology and spread of HCV. OBJECTIVE To describe the Hepatitis C virus (HCV) genotype distribution of newly acquired HCV infections in the province of British Columbia for the period 2000-2013. METHODS A descriptive cross-sectional analysis of multi-year data on HCV genotypes. Time trends for the proportion of different HCV genotypes are presented only for newly acquired (incident) HCV infections. RESULTS For acute cases, genotype 1a remains the dominant HCV type in circulation (50%), followed by genotype 3a (34%). HCV genotype 1b declined, while genotype 2 was relatively stable. Phylogenetically-related clusters of HCV strains were observed indicating a common source of infection. CONCLUSION Enhanced hepatitis surveillance provides a mechanism for monitoring different HCV strains currently circulating in the community. While HCV genotype 1a continues to be the most prevalent, changes in the relative frequency of genotypes 1 and 3 have been observed. This may have important implications for the control and prevention of the infection.
Collapse
Affiliation(s)
- A Andonov
- National Microbiology Laboratory, Public Health Agency of Canada, WinnipegMB
| | - L Lin
- National Microbiology Laboratory, Public Health Agency of Canada, WinnipegMB
| | - L McGuinness
- Public Health Microbiology and Reference Laboratory, British Columbia Centre for Disease Control, Vancouver, BC
| | - M Krajden
- Public Health Microbiology and Reference Laboratory, British Columbia Centre for Disease Control, Vancouver, BC
| |
Collapse
|
5
|
McGuinness L, Taylor C, Taylor RDT, Yau C, Langenhan T, Hart ML, Christian H, Tynan PW, Donnelly P, Emptage NJ. Presynaptic NMDARs in the hippocampus facilitate transmitter release at theta frequency. Neuron 2011; 68:1109-27. [PMID: 21172613 DOI: 10.1016/j.neuron.2010.11.023] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2010] [Indexed: 11/19/2022]
Abstract
A rise in [Ca(2+)](i) provides the trigger for neurotransmitter release at neuronal boutons. We have used confocal microscopy and Ca(2+) sensitive dyes to directly measure the action potential-evoked [Ca(2+)](i) in the boutons of Schaffer collaterals. This reveals that the trial-by-trial amplitude of the evoked Ca(2+) transient is bimodally distributed. We demonstrate that "large" Ca(2+) transients occur when presynaptic NMDA receptors are activated following transmitter release. Presynaptic NMDA receptor activation proves critical in producing facilitation of transmission at theta frequencies. Because large Ca(2+) transients "report" transmitter release, their frequency on a trial-by-trial basis can be used to estimate the probability of release, p(r). We use this novel estimator to show that p(r) increases following the induction of long-term potentiation.
Collapse
Affiliation(s)
- Lindsay McGuinness
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | | | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Moon HS, McGuinness L, Kukkadapu RK, Peacock AD, Komlos J, Kerkhof LJ, Long PE, Jaffé PR. Microbial reduction of uranium under iron- and sulfate-reducing conditions: Effect of amended goethite on microbial community composition and dynamics. Water Res 2010; 44:4015-4028. [PMID: 20541787 DOI: 10.1016/j.watres.2010.05.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 04/30/2010] [Accepted: 05/04/2010] [Indexed: 05/29/2023]
Abstract
There is a growing need for a better understanding of the biogeochemical dynamics involved in microbial U(VI) reduction due to an increasing interest in using biostimulation via electron donor addition as a means to remediate uranium contaminated sites. U(VI) reduction has been observed to be maximized during iron-reducing conditions and to decrease upon commencement of sulfate-reducing conditions. There are many unknowns regarding the impact of iron/sulfate biogeochemistry on U(VI) reduction. This includes Fe(III) availability as well as the microbial community changes, including the activity of iron-reducers during the uranium biostimulation period even after sulfate reduction becomes dominant. Column experiments were conducted with Old Rifle site sediments containing Fe-oxides, Fe-clays, and sulfate rich groundwater. Half of the columns had sediment that was augmented with small amounts of Fe(III) in the form of (57)Fe-goethite, allowing for a detailed tracking of minute changes of this added phase to study the effects of increased Fe(III) levels on the overall biostimulation dynamics. Mössbauer spectroscopy showed that the added (57)Fe-goethite was bioreduced only during the first thirty days of biostimultuion, after which it remained constant. Augmentation with Fe(III) had a significant effect on the total flux of electrons towards different electron acceptors; it suppressed the degree of sulfate reduction, had no significant impact on Geobacter-type bacterial numbers but decreased the bacterial numbers of sulfate reducers and affected the overall microbial community composition. The addition of Fe(III) had no noticeable effect on the total uranium reduction.
Collapse
Affiliation(s)
- H S Moon
- Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ 08544, USA
| | | | | | | | | | | | | | | |
Collapse
|
7
|
Jen A, Parkyn CJ, Mootoosamy RC, Ford MJ, Warley A, Liu Q, Bu G, Baskakov IV, Moestrup S, McGuinness L, Emptage N, Morris RJ. Neuronal low-density lipoprotein receptor-related protein 1 binds and endocytoses prion fibrils via receptor cluster 4. J Cell Sci 2010; 123:246-55. [PMID: 20048341 DOI: 10.1242/jcs.058099] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
For infectious prion protein (designated PrP(Sc)) to act as a template to convert normal cellular protein (PrP(C)) to its distinctive pathogenic conformation, the two forms of prion protein (PrP) must interact closely. The neuronal receptor that rapidly endocytoses PrP(C) is the low-density lipoprotein receptor-related protein 1 (LRP1). We show here that on sensory neurons LRP1 is also the receptor that binds and rapidly endocytoses smaller oligomeric forms of infectious prion fibrils, and recombinant PrP fibrils. Although LRP1 binds two molecules of most ligands independently to its receptor clusters 2 and 4, PrP(C) and PrP(Sc) fibrils bind only to receptor cluster 4. PrP(Sc) fibrils out-compete PrP(C) for internalization. When endocytosed, PrP(Sc) fibrils are routed to lysosomes, rather than recycled to the cell surface with PrP(C). Thus, although LRP1 binds both forms of PrP, it traffics them to separate fates within sensory neurons. The binding of both to ligand cluster 4 should enable genetic modification of PrP binding without disrupting other roles of LRP1 essential to neuronal viability and function, thereby enabling in vivo analysis of the role of this interaction in controlling both prion and LRP1 biology.
Collapse
Affiliation(s)
- Angela Jen
- Wolfson Centre for Age Related Disease, King's College London, SE1 1UL, UK
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Babcock DA, Wawrik B, Paul JH, McGuinness L, Kerkhof LJ. Rapid screening of a large insert BAC library for specific 16S rRNA genes using TRFLP. J Microbiol Methods 2007; 71:156-61. [PMID: 17888534 DOI: 10.1016/j.mimet.2007.07.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Accepted: 07/30/2007] [Indexed: 11/20/2022]
Abstract
It is widely believed that the vast majority of microbes in the environment have-yet-to-be cultured using standard techniques. Bulk DNA from microbial communities is therefore often cloned into large insert vectors (e.g. bacterial artificial chromosomes [BAC] or cosmids) in order to study the genetic properties of these as yet (un)-cultured bacteria. In a typical BAC experiment, tens of thousands of clones are generated with only a small fraction of colonies containing the target(s) of interest. Efficient screening methodologies are therefore needed to allow targeted clone isolation. In this paper, we describe a rapid, inexpensive protocol that allows for the identification of specific 16S ribosomal RNA genes in a metagenomic library arrayed into 384-well microtiter plates. The rapid screening protocol employs Terminal Restriction Fragment Length Polymorphism (TRFLP) analysis to identify wells containing specific T-RF peaks. A nested approach using multiplexed samples of 384, 48, 8, and single colony analysis is described and applied in order to survey a BAC library generated from a marine microbial community off the coast of New Jersey. Screening revealed a total of 50 different 16 rRNA genes within the BAC library. Overall, the multiplexing format provided a simple, cost effective methodology for detecting clones bearing a target gene of interest in a large clone library. However, the limitations of screening BAC libraries using PCR methodologies and recommendations for improved screening efficiency using this approach are also discussed.
Collapse
Affiliation(s)
- D A Babcock
- Department of Environmental Sciences at Rutgers University, Cook College, New Brunswick, New Jersey 08901-8521, USA
| | | | | | | | | |
Collapse
|
9
|
Ward B, McGuinness L, Akerman CJ, Fine A, Bliss TVP, Emptage NJ. State-dependent mechanisms of LTP expression revealed by optical quantal analysis. Neuron 2007; 52:649-61. [PMID: 17114049 DOI: 10.1016/j.neuron.2006.10.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2005] [Revised: 07/07/2006] [Accepted: 10/09/2006] [Indexed: 10/23/2022]
Abstract
The expression mechanism of long-term potentiation (LTP) remains controversial. Here we combine electrophysiology and Ca(2+) imaging to examine the role of silent synapses in LTP expression. Induction of LTP fails to change p(r) at these synapses but instead mediates an unmasking process that is sensitive to the inhibition of postsynaptic membrane fusion. Once unmasked, however, further potentiation of formerly silent synapses leads to an increase in p(r). The state of the synapse thus determines how LTP is expressed.
Collapse
Affiliation(s)
- Bonnie Ward
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | | | | | | | | | | |
Collapse
|
10
|
McGuinness L, Bardo SJ, Emptage NJ. The lysosome or lysosome-related organelle may serve as a Ca2+ store in the boutons of hippocampal pyramidal cells. Neuropharmacology 2007; 52:126-35. [PMID: 16930634 DOI: 10.1016/j.neuropharm.2006.07.029] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2006] [Revised: 07/17/2006] [Accepted: 07/17/2006] [Indexed: 10/24/2022]
Abstract
Boutons are specialised presynaptic compartments that lie along the axons of central neurons. Release of neurotransmitter from boutons is tightly regulated by the level of intracellular calcium [Ca2+]i. A rise in Ca2+ level may be generated in several ways; entry of extracellular Ca2+ via voltage gated calcium channels (VGCCs), entry via ligand-operated channels (LOCs) or the release of Ca2+ from intracellular Ca2+ stores. The role of Ca2+ stores in boutons remains poorly understood, despite recent work indicating that the release of Ca2+ from the endoplasmic reticulum (ER) may contribute to transmitter release. In this study we assess whether the lysosome or a closely related organelle functions as a Ca2+ store in the boutons of hippocampal pyramidal neurones. Lysosomes are small acidic organelles more commonly known for their role in degrading redundant cellular constituents. Using a fluorescent lysosomal marker, we show that lysosomes are located in the axons of hippocampal CA3 neurones. Selective pharmacological lysis of the lysosomes with glycyl-phenylalanine 2-naphthylamide (GPN) generates rapid, highly focal Ca2+ transients within the axon and increases the frequency of spontaneous miniature excitatory post-synaptic currents (mEPSCs), revealing that the organelle contains Ca2+ at a concentration sufficient to evoke transmitter release. Confocal laser scanning microscopy, combined with electrophysiology is used to monitor the action potential evoked increases in [Ca2+]i in boutons. We show that disruption of lysosomes compromises action potential evoked [Ca2+]i but this effect is occluded if the ER is discharged. Conversely, disruption of the lysosome does not appear to impact on the capacity of the ER to release Ca2+. These results suggest that the lysosome may serve as a Ca2+ store within hippocampal boutons, with a Ca2+ signalling role that is unique from that of the ER.
Collapse
Affiliation(s)
- Lindsay McGuinness
- University of Oxford, Department of Pharmacology, Mansfield Road, Oxford OX1 3QT, UK
| | | | | |
Collapse
|
11
|
Gallagher E, McGuinness L, Phelps C, Young LY, Kerkhof LJ. 13C-carrier DNA shortens the incubation time needed to detect benzoate-utilizing denitrifying bacteria by stable-isotope probing. Appl Environ Microbiol 2005; 71:5192-6. [PMID: 16151104 PMCID: PMC1214685 DOI: 10.1128/aem.71.9.5192-5196.2005] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The active bacterial community able to utilize benzoate under denitrifying conditions was elucidated in two coastal sediments using stable-isotope probing (SIP) and nosZ gene amplification. The SIP method employed samples from Norfolk Harbor, Virginia, and a Long-Term Ecosystem Observatory (no. 15) off the coast of Tuckerton, New Jersey. The SIP method was modified by use of archaeal carrier DNA in the density gradient separation. The carrier DNA significantly reduced the incubation time necessary to detect the (13)C-labeled bacterial DNA from weeks to hours in the coastal enrichments. No denitrifier DNA was found to contaminate the archaeal (13)C-carrier when [(12)C]benzoate was used as a substrate in the sediment enrichments. Shifts in the activity of the benzoate-utilizing denitrifying population could be detected throughout a 21-day incubation. These results suggest that temporal analysis using SIP can be used to illustrate the initial biodegrader(s) in a bacterial population and to document the cross-feeding microbial community.
Collapse
Affiliation(s)
- E Gallagher
- Institute of Marine and Coastal Sciences, Cook Campus, Rutgers University, 71 Dudley Road., New Brunswick, NJ 08901-8521, USA
| | | | | | | | | |
Collapse
|
12
|
Bennett E, McGuinness L, Gevers EF, Thomas GB, Robinson ICAF, Davey HW, Luckman SM. Hypothalamic STAT proteins: regulation of somatostatin neurones by growth hormone via STAT5b. J Neuroendocrinol 2005; 17:186-94. [PMID: 15796771 DOI: 10.1111/j.1365-2826.2005.01296.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Signal transducers and activators of transcription (STATs) are a family of transcription factors linked to class I cytokine receptors. In the present study, we investigated whether their distribution in the hypothalamus reflects the feedback regulation by growth hormone and what role they might play in the functioning of target neurones. We demonstrate that each of the seven known STATs has a distinct distribution in the hypothalamus. Notably, the STAT5 proteins, that are important in growth hormone (GH) and prolactin signalling in peripheral tissues, were expressed in somatostatin neurones of the periventricular nucleus and dopamine neurones of the arcuate nucleus. Because somatostatin neurones are regulated by feedback from circulating GH, we investigated the importance of STAT5 in these neurones. We demonstrate that STAT5b protein expression, similar to somatostatin mRNA, is sexually dimorphic in the periventricular nucleus of rats and mice. Furthermore, chronic infusion of male dwarf rats with GH increased the expression of STAT5b, while a single injection of GH into similar rats induced the phosphorylation of STAT5 proteins. The cellular abundance of somatostatin mRNA in STAT5b-deficient mice was significantly reduced in the periventricular nucleus, effectively reducing the sexually dimorphic expression. These results are consistent with the hypothesis that STAT5 proteins are involved in the feedback regulation of somatostatin neurones by GH, and that these neurones may respond to patterned GH secretion to reinforce sexual dimorphism in the GH axis.
Collapse
Affiliation(s)
- E Bennett
- Faculty of Life Sciences, University of Manchester, Manchester, UK
| | | | | | | | | | | | | |
Collapse
|
13
|
McGuinness L, Magoulas C, Sesay AK, Mathers K, Carmignac D, Manneville JB, Christian H, Phillips JA, Robinson ICAF. Autosomal dominant growth hormone deficiency disrupts secretory vesicles in vitro and in vivo in transgenic mice. Endocrinology 2003; 144:720-31. [PMID: 12538635 DOI: 10.1210/en.2002-220847] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Autosomal dominant GH deficiency type II (IGHDII) is often associated with mutations in the human GH gene (GH1) that give rise to products lacking exon-3 ((Deltaexon3)hGH). In the heterozygous state, these act as dominant negative mutations that prevent the release of human pituitary GH (hGH). To determine the mechanisms of these dominant negative effects, we used a combination of transgenic and morphological approaches in both in vitro and in vivo models. Rat GC cell lines were generated expressing either wild-type GH1 (WT-hGH-GC) or a genomic GH1 sequence containing a G->A transition at the donor splice site of IVS3 ((Deltaexon3)hGH-GC). WT-hGH-GC cells grew normally and produced equivalent amounts of human and rGH packaged in dense-cored secretory vesicles (SVs). In contrast, (Deltaexon3)hGH-GC cells showed few SVs but accumulated secretory product in amorphous cytoplasmic aggregates. They produced much less rGH and grew more slowly than WT-hGH-GC cells. When cotransfected with an enhanced green fluorescent protein construct (GH-eGFP), which copackages with GH in SVs, WT-hGH-GC cells showed normal electron microscopy morphology and SV movements, tracked with total internal reflectance fluorescence microscopy. In contrast, coexpression of (Deltaexon3)hGH with GH-eGFP abolished the vesicular targeting of GH-eGFP, which instead accumulated in static aggregates. Transgenic mice expressing (Deltaexon3)hGH in somatotrophs showed an IGHD-II phenotype with mild to severe pituitary hypoplasia and dwarfism, evident at weaning in the most severely affected lines. Hypothalamic GHRH expression was up-regulated and somatostatin expression reduced in (Deltaexon3)hGH transgenic mice, consistent with their profound GHD. Few SVs were detectable in the residual pituitary somatotrophs in (Deltaexon3)hGH transgenic mice, and these cells showed grossly abnormal morphology. A low copy number transgenic line showed a mild effect relatively specific for GH, whereas two severely affected lines with higher transgene copy numbers showed early onset, widespread pituitary damage, macrophage invasion, and multiple hormone deficiencies. These new in vitro and in vivo models shed new light on the cellular mechanisms involved in IGHDII, as well as its phenotypic consequences in vivo.
Collapse
Affiliation(s)
- Lindsay McGuinness
- National Institute for Medical Research, Mill Hill, London NW7 1AA, United Kingdom
| | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Abstract
AIM OF THE STUDY To present the results of evaluation research investigating a successful community development project. RATIONALE Many governments, health care agencies, and organizations require community participation in health care. As a result, nurses and other health professionals are often required to practice using a philosophy of community development. Although the theoretical, philosophical, and practical components of community development are well articulated, there is little evidence that exemplifies the experience of initiating and participating in a community development project. This paper provides evidence of how one organization successfully engaged the broader community on a respite care project. METHOD Using qualitative research methods and guided by the principles and practices of participatory action research, this evaluation engaged with the community in data collection, analysis, dissemination of finding, and in promoting effective change. RESULTS Four themes emerged that provide insight into how one HIV/AIDS organization successfully undertook community development. These themes include: (a) identifying a community need; (b) addressing the various components identified in the community development process; (c) highlighting the strategies used to engage in successful community development; and (d) attending to factors that influence community development. CONCLUSION The results of this research contribute to the body of knowledge related to engaging in the process of community development. By highlighting the experiences of one community group, it is hoped that nurses can learn and incorporate this knowledge into practice.
Collapse
Affiliation(s)
- E Lindsey
- University of Victoria, British Columbia, Canada.
| | | | | |
Collapse
|
15
|
Magoulas C, McGuinness L, Balthasar N, Carmignac DF, Sesay AK, Mathers KE, Christian H, Candeil L, Bonnefont X, Mollard P, Robinson IC. A secreted fluorescent reporter targeted to pituitary growth hormone cells in transgenic mice. Endocrinology 2000; 141:4681-9. [PMID: 11108283 DOI: 10.1210/endo.141.12.7828] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In stable transfection experiments in the GH-producing GC cell line, a construct containing the entire signal peptide and the first 22 residues of human GH linked in frame with enhanced green fluorescent protein (eGFP), produced brightly fluorescent cells with a granular distribution of eGFP. This eGFP reporter was then inserted into a 40-kb cosmid transgene containing the locus control region for the hGH gene and used to generate transgenic mice. Anterior pituitaries from these GH-eGFP transgenic mice showed numerous clusters of strongly fluorescent cells, which were also immunopositive for GH, and which could be isolated and enriched by fluorescence-activated cell sorting. Confocal scanning microscopy of pituitary GH cells from GH-eGFP transgenic mice showed a markedly granular appearance of fluorescence. Immunogold electron microscopy and RIA confirmed that the eGFP product was packaged in the dense cored secretory vesicles of somatotrophs and was secreted in parallel with GH in response to stimulation by GRF. Using eGFP fluorescence, it was possible to identify clusters of GH cells in acute pituitary slices and to observe spontaneous transient rises in their intracellular Ca2+ concentrations after loading with Ca2+ sensitive dyes. This transgenic approach opens the way to direct visualization of spontaneous and secretagogue-induced secretory mechanisms in identified GH cells.
Collapse
Affiliation(s)
- C Magoulas
- Division of Neurophysiology, National Institute for Medical Research Mill Hill, London, United Kingdom
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Abstract
Participatory action research (PAR) has been heralded as an important research methodology to address issues of research relevance, community involvement, democracy, emancipation and liberation. Increasingly, nurse researchers are turning to PAR as a method of choice. Although nursing interest in PAR is expanding little is known about how to successfully involve the community in research. This article attends to this dearth of information by presenting the results of a study investigating the significant elements of community involvement in PAR. Through the use of qualitative research methods, five themes emerged that describe the community participation process: (a) planning for participation, (b) the structural components of community participation, (c) living the philosophy, (d) enhancing the credibility, and (e) the type of leadership required to facilitate community participation. It is hoped that by sharing these results others may consider the knowledge gleaned from this project as they plan and proceed with the challenges and rewards inherent in PAR.
Collapse
Affiliation(s)
- E Lindsey
- School of Nursing, University of Victoria, British Columbia, Canada
| | | |
Collapse
|
17
|
Abstract
Data collection and validation for the Liverpool Congenital Malformations Registry (LCMR) are described. Founded in 1960, the LCMR increased its area of surveillance in 1979 to include five health districts in Liverpool and its environs with approximately 20,000 births per annum. The LCMR is now one of the members of the European Congenital Anomalies Register (EUROCAT). Multiple sources of ascertainment are employed, the most useful of these being OPCS notifications, hospital discharge letters and data from specialised paediatric units. In spite of several difficulties encountered in data collection the data base is an invaluable tool both for routine monitoring of prevalence rates and as a starting point for epidemiological research.
Collapse
Affiliation(s)
- J R Owens
- Liverpool Congenital Malformations Registry, Institute of Child Health, UK
| | | | | | | |
Collapse
|
18
|
McGuinness L, Kline T. Hospital breaks new ground with hybrid financing package. Trustee 1984; 37:21-2. [PMID: 10264904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
By applying financial management techniques that are more traditionally associated with corporate businesses, an Illinois hospital was able to generate the funds needed for a new replacement facility at a time when the money market was especially tight. The authors explain the structure of the hybrid financing package they used, and how such a strategy enabled the hospital to generate $61 million in capital at an interest rate almost 5 percent below prime.
Collapse
|