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1.
West J Emerg Med ; 23(5): 716-723, 2022 Aug 28.
Article in English | MEDLINE | ID: mdl-36205678

ABSTRACT

INTRODUCTION: Research suggests that pain assessment involves a complex interaction between patients and clinicians. We sought to assess the agreement between pain scores reported by the patients themselves and the clinician's perception of a patient's pain in the emergency department (ED). In addition, we attempted to identify patient and physician factors that lead to greater discrepancies in pain assessment. METHODS: We conducted a prospective observational study in the ED of a tertiary academic medical center. Using a standard protocol, trained research personnel prospectively enrolled adult patients who presented to the ED. The entire triage process was recorded, and triage data were collected. Pain scores were obtained from patients on a numeric rating scale of 0 to 10. Five physician raters provided their perception of pain ratings after reviewing videos. RESULTS: A total of 279 patients were enrolled. The mean age was 53 years. There were 141 (50.5%) female patients. The median self-reported pain score was 4 (interquartile range 0-6). There was a moderately positive correlation between self-reported pain scores and physician ratings of pain (correlation coefficient, 0.46; P <0.001), with a weighted kappa coefficient of 0.39. Some discrepancies were noted: 102 (37%) patients were rated at a much lower pain score, whereas 52 (19%) patients were given a much higher pain score from physician review. The distributions of chief complaints were different between the two groups. Physician raters tended to provide lower pain scores to younger (P = 0.02) and less ill patients (P = 0.008). Additionally, attending-level physician raters were more likely to provide a higher pain score than resident-level raters (P <0.001). CONCLUSION: Patients' self-reported pain scores correlate positively with the pain score provided by physicians, with only a moderate agreement between the two. Under- and over-estimations of pain in ED patients occur in different clinical scenarios. Pain assessment in the ED should consider both patient and physician factors.


Subject(s)
Emergency Service, Hospital , Triage , Adult , Female , Humans , Male , Middle Aged , Pain/diagnosis , Pain/etiology , Pain Measurement , Prospective Studies
2.
Acad Emerg Med ; 29(9): 1050-1056, 2022 09.
Article in English | MEDLINE | ID: mdl-35785459

ABSTRACT

OBJECTIVE: Appropriate triage in patients presenting to the emergency department (ED) is often challenging. Little is known about the role of physician gestalt in ED triage. We aimed to compare the accuracy of emergency physician gestalt against the currently used computerized triage process. METHODS: We conducted a prospective observational study in the ED at an academic medical center. Adult patients aged ≥20 years were included and underwent a standard triage protocol. The patients underwent system-based triage using the computerized software the Taiwan Triage and Acuity Scale. The entire triage process was recorded, and triage data were collected. Five physician raters provided triage levels (physician-based) according to their perceived urgency after reviewing videos. The primary outcome was hospital admission. The secondary outcomes were ED length of stay (EDLOS) and charges. RESULTS: In total, 656 patients were recruited (mean age 52 years, 50% male). The median system-based triage level was 3. By contrast, the median physician-based triage level was 4. The physician raters tended to provide lower triage levels than the system, with an average difference of 1. There was modest concordance between the two triage methods (correlation coefficient 0.30), with a weighted kappa coefficient of 0.18. The area under the receiver operating curve for the system- and physician-based triage in predicting hospital admission were similar (0.635 vs. 0.631, p = 0.896). Attending physicians appeared to have better performance than residents in predicting admission. The variation explained (R2 ) in EDLOS and charges were similar between the two triage methods (R2  = 3% for EDLOS, 7%-9% for charges). CONCLUSIONS: Emergency physician gestalt for triage showed similar performance to a computerized system; however, physicians redistributed patients to lower triage levels. Physician gestalt has advantages for identifying low-risk patients. This approach may avoid undue time pressure for health care providers and promote rapid discharge.


Subject(s)
Physicians , Triage , Adult , Emergency Service, Hospital , Female , Humans , Male , Middle Aged , Patient Discharge , Prospective Studies , Triage/methods
3.
Am J Emerg Med ; 55: 111-116, 2022 05.
Article in English | MEDLINE | ID: mdl-35306437

ABSTRACT

BACKGROUND: Little is known about pain trajectories in the emergency department (ED), which could inform the heterogeneous response to pain treatment. We aimed to identify clinically relevant subphenotypes of pain resolution in the ED and their relationships with clinical outcomes. METHODS: This retrospective cohort study used electronic clinical warehouse data from a tertiary medical center. We retrieved data from 733,398 ED visits over a 7-year period. We selected one ED visit per person and retrieved data including patient demographics, triage data, repeated pain scores evaluated on a numeric rating scale, pain characteristics, laboratory markers, and patient disposition. The primary outcome measures were hospitalization and ED revisit. RESULTS: 28,105 adult ED patients were included with a total of 154,405 pain measurements. Three distinct pain trajectory groups were identified: no pain (57.1%); moderate-to-severe pain, fast resolvers (17.9%); and moderate pain, slow resolvers (24.9%). The fast resolvers responded well to treatment and were independently associated with a lower risk of hospitalization (adjusted odds ratio [aOR], 0.75; 95% confidence interval [CI], 0.70-0.81). By contrast, the slow resolvers had lingering pain in the ED and were independently associated with a higher risk of ED revisit (aOR, 2.65; 95%CI, 1.85-3.69). This group also had higher levels of inflammatory markers, including a higher leukocyte count and a higher level of C-reactive protein. CONCLUSIONS: We identified three novel pain subphenotypes with distinct patterns in clinical characteristics and patient outcomes. A better understanding of the pain trajectories may help with the personalized approach to pain management in the ED.


Subject(s)
Emergency Service, Hospital , Triage , Adult , Biomarkers , Hospitalization , Humans , Pain , Retrospective Studies
4.
PLoS One ; 16(6): e0252841, 2021.
Article in English | MEDLINE | ID: mdl-34161378

ABSTRACT

BACKGROUND: Outbreaks of emerging infectious diseases, such as COVID-19, have negative impacts on bystander cardiopulmonary resuscitation (BCPR) for fear of transmission while breaking social distancing rules. The latest guidelines recommend hands-only cardiopulmonary resuscitation (CPR) and facemask use. However, public willingness in this setup remains unknown. METHODS: A cross-sectional, unrestricted volunteer Internet survey was conducted to assess individuals' attitudes and behaviors toward performing BCPR, pre-existing CPR training, occupational identity, age group, and gender. The raking method for weights and a regression analysis for the predictors of willingness were performed. RESULTS: Among 1,347 eligible respondents, 822 (61%) had negative attitudes toward performing BCPR. Healthcare providers (HCPs) and those with pre-existing CPR training had fewer negative attitudes (p < 0.001); HCPs and those with pre-existing CPR training and unchanged attitude showed more positive behaviors toward BCPR (p < 0.001). Further, 9.7% of the respondents would absolutely refuse to perform BCPR. In contrast, 16.9% would perform BCPR directly despite the outbreak. Approximately 9.9% would perform it if they were instructed, 23.5%, if they wore facemasks, and 40.1%, if they were to perform hands-only CPR. Interestingly, among the 822 respondents with negative attitudes, over 85% still tended to perform BCPR in the abovementioned situations. The weighted analysis showed similar results. The adjusted predictors for lower negative attitudes toward BCPR were younger age, being a man, and being an HCP; those for more positive behaviors were younger age and being an HCP. CONCLUSIONS: Outbreaks of emerging infectious diseases, such as COVID-19, have negative impacts on attitudes and behaviors toward BCPR. Younger individuals, men, HCPs, and those with pre-existing CPR training tended to show fewer negative attitudes and behaviors. Meanwhile, most individuals with negative attitudes still expressed positive behaviors under safer measures such as facemask protection, hands-only CPR, and available dispatch instructions.


Subject(s)
COVID-19/epidemiology , Cardiopulmonary Resuscitation/psychology , Public Opinion , Adult , Aged , Cardiopulmonary Resuscitation/education , Cardiopulmonary Resuscitation/methods , Cross-Sectional Studies , Female , Hand , Health Knowledge, Attitudes, Practice , Health Personnel/psychology , Humans , Male , Masks , Middle Aged , Taiwan , Young Adult
5.
Cell Rep ; 26(7): 1774-1786.e4, 2019 02 12.
Article in English | MEDLINE | ID: mdl-30759389

ABSTRACT

Pathogenic mutations in leucine-rich repeat kinase 2 (LRRK2) induce an age-dependent loss of dopaminergic (DA) neurons. We have identified Furin 1, a pro-protein convertase, as a translational target of LRRK2 in DA neurons. Transgenic knockdown of Furin1 or its substrate the bone morphogenic protein (BMP) ligand glass bottom boat (Gbb) protects against LRRK2-induced loss of DA neurons. LRRK2 enhances the accumulation of phosphorylated Mad (pMad) in the nuclei of glial cells in the vicinity of DA neurons but not in DA neurons. Consistently, exposure to paraquat enhances Furin 1 levels in DA neurons and induces BMP signaling in glia. In support of a neuron-glial signaling model, knocking down BMP pathway members only in glia, but not in neurons, can protect against paraquat toxicity. We propose that a neuron-glial BMP-signaling cascade is critical for mediating age-dependent neurodegeneration in two models of Parkinson's disease, thus opening avenues for future therapeutic interventions.


Subject(s)
Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/genetics , Neurodegenerative Diseases/genetics , Neuroglia/metabolism , Humans , Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/metabolism , Signal Transduction
6.
PLoS Genet ; 14(1): e1007184, 2018 01.
Article in English | MEDLINE | ID: mdl-29373576

ABSTRACT

Retrograde signaling is essential for neuronal growth, function and survival; however, we know little about how signaling endosomes might be directed from synaptic terminals onto retrograde axonal pathways. We have identified Khc-73, a plus-end directed microtubule motor protein, as a regulator of sorting of endosomes in Drosophila larval motor neurons. The number of synaptic boutons and the amount of neurotransmitter release at the Khc-73 mutant larval neuromuscular junction (NMJ) are normal, but we find a significant decrease in the number of presynaptic release sites. This defect in Khc-73 mutant larvae can be genetically enhanced by a partial genetic loss of Bone Morphogenic Protein (BMP) signaling or suppressed by activation of BMP signaling in motoneurons. Consistently, activation of BMP signaling that normally enhances the accumulation of phosphorylated form of BMP transcription factor Mad in the nuclei, can be suppressed by genetic removal of Khc-73. Using a number of assays including live imaging in larval motor neurons, we show that loss of Khc-73 curbs the ability of retrograde-bound endosomes to leave the synaptic area and join the retrograde axonal pathway. Our findings identify Khc-73 as a regulator of endosomal traffic at the synapse and modulator of retrograde BMP signaling in motoneurons.


Subject(s)
Bone Morphogenetic Proteins/metabolism , Drosophila Proteins/physiology , Endosomes/metabolism , Kinesins/physiology , Neuromuscular Junction/metabolism , Animals , Animals, Genetically Modified , Drosophila Proteins/genetics , Drosophila melanogaster/embryology , Drosophila melanogaster/genetics , Drosophila melanogaster/metabolism , Embryo, Nonmammalian , Gene Expression Regulation, Developmental , Kinesins/genetics , Motor Neurons/metabolism , Presynaptic Terminals/metabolism , Signal Transduction/genetics , Signal Transduction/physiology , Synapses/metabolism
7.
Clin Pharmacol Drug Dev ; 7(2): 110-122, 2018 02.
Article in English | MEDLINE | ID: mdl-29197175

ABSTRACT

Given their established analgesic properties, nonsteroidal anti-inflammatory drugs (NSAIDs) represent an important postoperative pain management option. This study investigated: (1) the effects of mild or moderate renal insufficiency and mild hepatic impairment on the pharmacokinetics (PK) of diclofenac and hydroxypropyl-ß-cyclodextrin (HPßCD) following administration of the injectable NSAID HPßCD-diclofenac; and (2) the PK of HPßCD following administration of HPßCD-diclofenac and intravenous itraconazole formulated with HPßCD in healthy adults. Diclofenac clearance (CL) and volume of distribution (Vz ) tended to increase with decreasing renal function (moderate insufficiency versus mild insufficiency or healthy controls). Regression analysis demonstrated a significant relationship between Vz (but not CL or elimination half-life, t½ ) and renal function. HPßCD CL was significantly decreased in subjects with renal insufficiency, with a corresponding increase in t½ . There were no significant differences in diclofenac or HPßCD PK in subjects with mild hepatic impairment versus healthy subjects. Exposure to HPßCD in healthy subjects following HPßCD-diclofenac administration was ∼12% of that with intravenous itraconazole, after adjusting for dosing schedule and predicted accumulation (<5% without adjustment). With respect to PK properties, these results suggest that HPßCD-diclofenac might be administered to patients with mild or moderate renal insufficiency or mild hepatic impairment without dose adjustment (NCT00805090).


Subject(s)
2-Hydroxypropyl-beta-cyclodextrin/pharmacokinetics , Anti-Inflammatory Agents, Non-Steroidal/pharmacokinetics , Diclofenac/pharmacokinetics , Liver Diseases/metabolism , Renal Insufficiency/metabolism , 2-Hydroxypropyl-beta-cyclodextrin/administration & dosage , 2-Hydroxypropyl-beta-cyclodextrin/adverse effects , 2-Hydroxypropyl-beta-cyclodextrin/blood , Adult , Aged , Anti-Inflammatory Agents, Non-Steroidal/administration & dosage , Anti-Inflammatory Agents, Non-Steroidal/adverse effects , Anti-Inflammatory Agents, Non-Steroidal/blood , Diclofenac/administration & dosage , Diclofenac/adverse effects , Diclofenac/blood , Female , Humans , Injections, Intravenous , Male , Middle Aged
8.
Nat Commun ; 7: 12188, 2016 07 19.
Article in English | MEDLINE | ID: mdl-27432119

ABSTRACT

Parkinson's disease gene leucine-rich repeat kinase 2 (LRRK2) has been implicated in a number of processes including the regulation of mitochondrial function, autophagy and endocytic dynamics; nevertheless, we know little about its potential role in the regulation of synaptic plasticity. Here we demonstrate that postsynaptic knockdown of the fly homologue of LRRK2 thwarts retrograde, homeostatic synaptic compensation at the larval neuromuscular junction. Conversely, postsynaptic overexpression of either the fly or human LRRK2 transgene induces a retrograde enhancement of presynaptic neurotransmitter release by increasing the size of the release ready pool of vesicles. We show that LRRK2 promotes cap-dependent translation and identify Furin 1 as its translational target, which is required for the synaptic function of LRRK2. As the regulation of synaptic homeostasis plays a fundamental role in ensuring normal and stable synaptic function, our findings suggest that aberrant function of LRRK2 may lead to destabilization of neural circuits.


Subject(s)
Drosophila Proteins/metabolism , Drosophila melanogaster/metabolism , Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/metabolism , Neuromuscular Junction/metabolism , Synapses/metabolism , Animals , Furin/metabolism , HEK293 Cells , Homeostasis , Humans , Larva/metabolism , Mutant Proteins/metabolism , Mutation/genetics , Neurotransmitter Agents/metabolism , Protein Biosynthesis , RNA Caps/metabolism , Signal Transduction , Synaptic Transmission , Synaptic Vesicles/metabolism
9.
EMBO J ; 32(12): 1745-60, 2013 Jun 12.
Article in English | MEDLINE | ID: mdl-23665919

ABSTRACT

A neuronal F-box protein FSN-1 regulates Caenorhabditis elegans neuromuscular junction development by negatively regulating DLK-mediated MAPK signalling. In the present study, we show that attenuation of insulin/IGF signalling also contributes to FSN-1-dependent synaptic development and function. The aberrant synapse morphology and synaptic transmission in fsn-1 mutants are partially and specifically rescued by reducing insulin/IGF-signalling activity in postsynaptic muscles, as well as by reducing the activity of EGL-3, a prohormone convertase that processes agonistic insulin/IGF ligands INS-4 and INS-6, in neurons. FSN-1 interacts with, and potentiates the ubiquitination of EGL-3 in vitro, and reduces the EGL-3 level in vivo. We propose that FSN-1 may negatively regulate insulin/IGF signalling, in part, through EGL-3-dependent insulin-like ligand processing.


Subject(s)
Caenorhabditis elegans Proteins/metabolism , Caenorhabditis elegans/metabolism , F-Box Proteins/metabolism , Insulin/metabolism , MAP Kinase Signaling System/physiology , Muscles/metabolism , Synapses/metabolism , Animals , Caenorhabditis elegans/genetics , Caenorhabditis elegans Proteins/genetics , F-Box Proteins/genetics , HEK293 Cells , Humans , Insulin/genetics , MAP Kinase Kinase Kinases/genetics , MAP Kinase Kinase Kinases/metabolism , Mutation , Proprotein Convertase 2/genetics , Proprotein Convertase 2/metabolism , Somatomedins/genetics , Somatomedins/metabolism , Synapses/genetics , Ubiquitination/physiology
10.
Neuron ; 74(1): 166-78, 2012 Apr 12.
Article in English | MEDLINE | ID: mdl-22500638

ABSTRACT

Homeostatic mechanisms operate to stabilize synaptic function; however, we know little about how they are regulated. Exploiting Drosophila genetics, we have uncovered a critical role for the target of rapamycin (TOR) in the regulation of synaptic homeostasis at the Drosophila larval neuromuscular junction. Loss of postsynaptic TOR disrupts a retrograde compensatory enhancement in neurotransmitter release that is normally triggered by a reduction in postsynaptic glutamate receptor activity. Moreover, postsynaptic overexpression of TOR or a phosphomimetic form of S6 ribosomal protein kinase, a common target of TOR, can trigger a strong retrograde increase in neurotransmitter release. Interestingly, heterozygosity for eIF4E, a critical component of the cap-binding protein complex, blocks the retrograde signal in all these cases. Our findings suggest that cap-dependent translation under the control of TOR plays a critical role in establishing the activity dependent homeostatic response at the NMJ.


Subject(s)
Drosophila Proteins/metabolism , Gene Expression Regulation/physiology , Homeostasis/physiology , Neuromuscular Junction/metabolism , Protein Kinases/metabolism , Synaptic Transmission/physiology , Animals , Drosophila , Drosophila Proteins/genetics , Eukaryotic Initiation Factor-4E/genetics , Eukaryotic Initiation Factor-4E/physiology , Exocytosis/physiology , Larva/metabolism , Motor Neurons/metabolism , Mutation , Protein Kinases/genetics , Protein Transport/physiology , Receptors, Glutamate/metabolism , Ribosomal Protein S6 Kinases/metabolism , Signal Transduction/physiology , TOR Serine-Threonine Kinases
11.
Neuron ; 68(5): 879-93, 2010 Dec 09.
Article in English | MEDLINE | ID: mdl-21145002

ABSTRACT

Emerging data implicate microRNAs (miRNAs) in the regulation of synaptic structure and function, but we know little about their role in the regulation of neurotransmission in presynaptic neurons. Here, we demonstrate that the miR-310-313 cluster is required for normal synaptic transmission at the Drosophila larval neuromuscular junction. Loss of miR-310-313 cluster leads to a significant enhancement of neurotransmitter release, which can be rescued with temporally restricted expression of mir-310-313 in larval presynaptic neurons. Kinesin family member, Khc-73 is a functional target for miR-310-313 as its expression is increased in mir-310-313 mutants and reducing it restores normal synaptic function. Cluster mutants show an increase in the active zone protein Bruchpilot accompanied by an increase in electron dense T bars. Finally, we show that repression of Khc-73 by miR-310-313 cluster influences the establishment of normal synaptic homeostasis. Our findings establish a role for miRNAs in the regulation of neurotransmitter release.


Subject(s)
Drosophila Proteins/genetics , Drosophila/genetics , MicroRNAs/genetics , Neuromuscular Junction/genetics , Synaptic Transmission/genetics , Animals , Drosophila/growth & development , Drosophila/metabolism , Drosophila Proteins/metabolism , Kinesins/metabolism , Larva/genetics , Larva/metabolism , Motor Neurons/metabolism , Multigene Family/genetics , Neuromuscular Junction/metabolism , Synaptic Transmission/physiology
12.
Neuron ; 66(4): 536-49, 2010 May 27.
Article in English | MEDLINE | ID: mdl-20510858

ABSTRACT

Retrograde signaling is essential for coordinating the growth of synaptic structures; however, it is not clear how it can lead to modulation of cytoskeletal dynamics and structural changes at presynaptic terminals. We show that loss of retrograde bone morphogenic protein (BMP) signaling at the Drosophila larval neuromuscular junction (NMJ) leads to a significant reduction in levels of Rac GEF Trio and a diminution of transcription at the trio locus. We further find that Trio is required in motor neurons for normal structural growth. Finally, we show that transgenic expression of Trio in motor neurons can partially restore NMJ defects in larvae mutant for BMP signaling. Based on our findings, we propose a model in which a retrograde BMP signal from the muscle modulates GTPase activity through transcriptional regulation of Rac GEF trio, thereby regulating the homeostasis of synaptic growth at the NMJ.


Subject(s)
Bone Morphogenetic Proteins/physiology , Drosophila Proteins/biosynthesis , Guanine Nucleotide Exchange Factors/biosynthesis , Motor Neurons/physiology , Neuromuscular Junction/physiology , Phosphoproteins/biosynthesis , Protein Serine-Threonine Kinases/biosynthesis , Synapses/physiology , Animals , Cell Line , Drosophila , Gene Expression Regulation, Developmental , Humans , Signal Transduction/physiology , Synapses/ultrastructure
13.
Traffic ; 9(5): 742-54, 2008 May.
Article in English | MEDLINE | ID: mdl-18298590

ABSTRACT

Intersectins (Itsn) are conserved EH and SH3 domain containing adaptor proteins. In Drosophila melanogaster, ITSN is required to regulate synaptic morphology, to facilitate efficient synaptic vesicle recycling and for viability. Here, we report our genetic analysis of Caenorhabditis elegans intersectin. In contrast to Drosophila, C. elegans itsn-1 protein null mutants are viable and display grossly normal locomotion and development. However, motor neurons in these mutants show a dramatic increase in large irregular vesicles and accumulate membrane-associated vesicles at putative endocytic hotspots, approximately 300 nm from the presynaptic density. This defect occurs precisely where endogenous ITSN-1 protein localizes in wild-type animals and is associated with a significant reduction in synaptic vesicle number and reduced frequency of endogenous synaptic events at neuromuscular junctions (NMJs). ITSN-1 forms a stable complex with EHS-1 (Eps15) and is expressed at reduced levels in ehs-1 mutants. Thus, ITSN-1 together with EHS-1, coordinate vesicle recycling at C. elegans NMJs. We also found that both itsn-1 and ehs-1 mutants show poor viability and growth in a Disabled (dab-1) null mutant background. These results show for the first time that intersectin and Eps15 proteins function in the same genetic pathway, and appear to function synergistically with the clathrin-coat-associated sorting protein, Disabled, for viability.


Subject(s)
Adaptor Proteins, Vesicular Transport/metabolism , Caenorhabditis elegans Proteins/metabolism , Neuromuscular Junction/physiology , Synaptic Vesicles/metabolism , Adaptor Proteins, Vesicular Transport/genetics , Animals , Animals, Genetically Modified , Caenorhabditis elegans/anatomy & histology , Caenorhabditis elegans/genetics , Caenorhabditis elegans/physiology , Caenorhabditis elegans Proteins/genetics , Drosophila melanogaster , Endocytosis , Gene Deletion , Genes, Reporter , Humans , Intracellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Patch-Clamp Techniques , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/metabolism , Synapses/metabolism , Synapses/ultrastructure , Synaptic Transmission/physiology , Synaptic Vesicles/ultrastructure , Two-Hybrid System Techniques
14.
Nature ; 430(6997): 345-50, 2004 Jul 15.
Article in English | MEDLINE | ID: mdl-15208641

ABSTRACT

During synapse formation, specialized subcellular structures develop at synaptic junctions in a tightly regulated fashion. Cross-signalling initiated by ephrins, Wnts and transforming growth factor-beta family members between presynaptic and postsynaptic termini are proposed to govern synapse formation. It is not well understood how multiple signals are integrated and regulated by developing synaptic termini to control synaptic differentiation. Here we report the identification of FSN-1, a novel F-box protein that is required in presynaptic neurons for the restriction and/or maturation of synapses in Caenorhabditis elegans. Many F-box proteins are target recognition subunits of SCF (Skp, Cullin, F-box) ubiquitin-ligase complexes. fsn-1 functions in the same pathway as rpm-1, a gene encoding a large protein with RING finger domains. FSN-1 physically associates with RPM-1 and the C. elegans homologues of SKP1 and Cullin to form a new type of SCF complex at presynaptic periactive zones. We provide evidence that T10H9.2, which encodes the C. elegans receptor tyrosine kinase ALK (anaplastic lymphoma kinase), may be a target or a downstream effector through which FSN-1 stabilizes synapse formation. This neuron-specific, SCF-like complex therefore provides a localized signal to attenuate presynaptic differentiation.


Subject(s)
Caenorhabditis elegans Proteins/metabolism , Caenorhabditis elegans/cytology , Caenorhabditis elegans/enzymology , Cell Differentiation , F-Box Proteins/metabolism , SKP Cullin F-Box Protein Ligases/chemistry , SKP Cullin F-Box Protein Ligases/metabolism , Synapses/enzymology , Anaplastic Lymphoma Kinase , Animals , Caenorhabditis elegans Proteins/genetics , F-Box Proteins/genetics , Gene Expression Regulation , Guanine Nucleotide Exchange Factors/genetics , Guanine Nucleotide Exchange Factors/metabolism , Macromolecular Substances , Mutation/genetics , Neurons/cytology , Neurons/enzymology , Neurons/metabolism , Organ Specificity , Protein Binding , Protein-Tyrosine Kinases/antagonists & inhibitors , Protein-Tyrosine Kinases/metabolism , Receptor Protein-Tyrosine Kinases , SKP Cullin F-Box Protein Ligases/genetics , Signal Transduction , Substrate Specificity , Synapses/metabolism
15.
Infect Immun ; 72(5): 2742-52, 2004 May.
Article in English | MEDLINE | ID: mdl-15102784

ABSTRACT

Individual Neisseria gonorrhoeae colony opacity-associated (Opa) protein variants can bind up to four different carcinoembryonic antigen-related cellular adhesion molecule (CEACAM) receptors. Most human cells encountered by gonococci express a combination of CEACAM receptors, thereby complicating the elucidation of intracellular signaling pathways triggered by individual receptors. Here, we compare the process of bacterial engulfment by a panel of stably transfected HeLa epithelial cell lines expressing each CEACAM receptor in isolation. CEACAM1 and CEACAM3 each contain proteinaceous transmembrane and cytoplasmic domains; however, the processes of neisserial uptake mediated by these receptors differ with respect to their susceptibilities to both tyrosine kinase inhibitors and the actin microfilament-disrupting agent cytochalasin D. Neisserial uptake mediated by glycosylphosphatidylinositol (GPI)-anchored CEACAM5 and CEACAM6 was not significantly affected by any of a broad spectrum of inhibitors tested. However, cleavage of the GPI anchor by phosphatidylinositol-specific phospholipase C reduced bacterial uptake by HeLa cells expressing CEACAM5, consistent with a single zipper-like mechanism of uptake mediated by this receptor. Regardless of the CEACAM receptor expressed, internalized gonococci were effectively killed by a microtubule-dependent process that required acidification of the bacterium-containing phagosome. Given the phase-variable nature of neisserial Opa proteins, these results indicate that the mechanism of bacterial engulfment and the cellular response to gonococcal infection depend on both the receptor specificities of the neisserial Opa protein variants expressed and the spectrum of CEACAM receptors present on target cells, each of which determines the combination of receptors ultimately engaged.


Subject(s)
Bacterial Adhesion/immunology , Integrins/physiology , Neisseria gonorrhoeae/immunology , Antigens, CD/genetics , Antigens, CD/physiology , Antigens, Differentiation/genetics , Antigens, Differentiation/physiology , Antigens, Neoplasm/genetics , Antigens, Neoplasm/physiology , Carcinoembryonic Antigen/genetics , Carcinoembryonic Antigen/physiology , Cell Adhesion Molecules/genetics , Cell Adhesion Molecules/physiology , Cytoskeleton/physiology , GPI-Linked Proteins , Glycosylphosphatidylinositols/physiology , HeLa Cells , Humans , Integrins/genetics , Kinetics , Models, Biological , Neisseria gonorrhoeae/pathogenicity , Phagocytosis , Phosphorylation , Transfection
16.
Mol Microbiol ; 49(3): 623-37, 2003 Aug.
Article in English | MEDLINE | ID: mdl-12864848

ABSTRACT

Gonorrhea is characterized by a purulent urethral or cervical discharge consisting primarily of neutrophils associated with Neisseria gonorrhoeae. These interactions are facilitated by gonococcal colony opacity-associated (Opa) protein binding to host cellular CEACAM receptors. Of these, CEACAM3 is restricted to neutrophils and contains an immunoreceptor tyrosine-based activation motif (ITAM) reminiscent of that found within certain phagocytic Fc receptors. CEACAM3 was tyrosine phosphorylated by a Src family kinase-dependent process upon infection by gonococci expressing CEACAM-specific Opa proteins. This phosphorylation was necessary for efficient bacterial uptake; however, a less efficient uptake process became evident when kinase inhibitors or mutagenesis of the ITAM were used to prevent phosphorylation. Ligated CEACAM3 was recruited to a cytoskeleton-containing fraction, intense foci of polymerized actin were evident where bacteria attached to HeLa-CEACAM3, and disruption of polymerized actin by cytochalasin D blocked all bacterial uptake by these cells. These data support a model whereby CEACAM3 can mediate the Opa-dependent uptake of N. gonorrhoeae via either an efficient, ITAM phosphorylation-dependent process that resembles phagocytosis or a less efficient, tyrosine phosphorylation-independent mechanism.


Subject(s)
Adhesins, Bacterial/metabolism , Bacterial Proteins/metabolism , Carcinoembryonic Antigen/metabolism , Neisseria gonorrhoeae/metabolism , Neutrophils/metabolism , Protein Processing, Post-Translational , Proteoglycans/metabolism , Receptors, Cell Surface/metabolism , src-Family Kinases/metabolism , Actin Cytoskeleton/ultrastructure , Adhesins, Bacterial/genetics , Amino Acid Motifs , Amino Acid Sequence , Antigens, Bacterial , Bacterial Proteins/genetics , Carcinoembryonic Antigen/chemistry , Carcinoembryonic Antigen/genetics , Cytoskeleton/metabolism , Cytoskeleton/ultrastructure , HeLa Cells/metabolism , HeLa Cells/microbiology , Humans , Molecular Sequence Data , Neisseria gonorrhoeae/genetics , Neutrophils/microbiology , Neutrophils/ultrastructure , Phosphorylation , Proteoglycans/genetics , Receptors, Cell Surface/genetics , Recombinant Fusion Proteins/metabolism , Transfection
17.
J Biol Chem ; 278(16): 14037-45, 2003 Apr 18.
Article in English | MEDLINE | ID: mdl-12571236

ABSTRACT

Neisseria gonorrhoeae can be internalized by mammalian cells through interactions between bacterial opacity-associated (Opa) adhesins and members of the human carcinoembryonic antigen-related cellular adhesion molecule (CEACAM) family. We examined the role of phosphatidylinositol 3-kinases (PI3Ks) in gonococcal invasion of epithelial cell lines expressing either CEACAM1 or CEACAM3. CEACAM3-mediated internalization, but not that mediated by CEACAM1, was accompanied by localized and transient accumulation of the class I PI3K product phosphatidylinositol 3,4,5-trisphosphate at sites of bacterial engulfment. Inhibition of phosphatidylinositol 3-kinases reduced CEACAM3-mediated uptake but, paradoxically, led to an increase in intracellular survival of bacteria internalized via either CEACAM1 or CEACAM3, suggesting additional roles for PI3K products. Consistent with this finding, the class III PI3K product phosphatidylinositol 3-phosphate accumulated and persisted in the membrane of gonococcal phagosomes after internalization. Inhibition of PI3K blocked phagosomal acquisition of the late endosomal marker lysosome-associated membrane protein 2 and reduced phagosomal acidification. Inhibiting phagosomal acidification with concanamycin A also increased survival of intracellular gonococci. These results suggest two modes of action of phosphatidylinositol 3-kinases during internalization of gonococci: synthesis of phosphatidylinositol 3,4,5-trisphosphate is important for CEACAM3-mediated uptake, while phosphatidylinositol 3-phosphate is needed for phagosomal maturation and acidification, which are required for optimal bacterial killing.


Subject(s)
Antigens, CD/metabolism , Antigens, Differentiation/metabolism , Carcinoembryonic Antigen/metabolism , Macrolides , Phosphatidylinositol 3-Kinases/physiology , Androstadienes/pharmacology , Anti-Bacterial Agents/pharmacology , Cell Adhesion Molecules , Cell Division , Cell Line , Cell Nucleus/metabolism , Chromones/pharmacology , Drug Resistance , Endosomes/metabolism , Enzyme Inhibitors/pharmacology , Epithelial Cells/metabolism , Epithelial Cells/microbiology , Gentamicins/pharmacology , HeLa Cells , Humans , Hydrogen-Ion Concentration , Lysosomes/metabolism , Microscopy, Confocal , Morpholines/pharmacology , Neisseria gonorrhoeae/metabolism , Phagosomes/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Plasmids/metabolism , Time Factors , Wortmannin
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