Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 18 de 18
Filter
1.
Contemp Clin Trials ; 108: 106506, 2021 09.
Article in English | MEDLINE | ID: mdl-34273551

ABSTRACT

OBJECTIVE: Caregivers of individuals with Alzheimer's disease and related dementias (ADRD) often experience debilitating caregiver burden and emotional distress. To address these negative emotional consequences of caregiving, we will test and refine a strategy training intervention - Problem-Solving Training (PST) - that promotes self-efficacy and reduces caregiver burden and depressive symptoms. Previous research supports efficacy of PST; however, we do not know exactly how many PST sessions are needed or if post-training "boosters" are required to maintain PST benefits. Additionally, we translated and culturally-adapted PST into "Descubriendo Soluciones Juntos" (DSJ), our novel intervention for Spanish-speaking caregivers. METHOD: In this 2 × 2 factorial design randomized controlled trial, we will test remotely-delivered PST/DSJ sessions for both English- and Spanish-speaking caregivers of persons with ADRD to determine the optimal number of PST/DSJ sessions and ongoing "booster" sessions needed to best help caregivers navigate their current and future needs. AIMS: 1) Compare the efficacy of three vs. six PST/DSJ sessions each with and without booster sessions for decreasing caregiver burden and depression and enhancing caregiver problem-solving; 2) Identify key factors associated with efficacy of PST/DSJ, including age, gender, primary language, relationship to care recipient, and uptake of the PST/DSJ strategy. RESULTS: These results will establish guidelines needed for an evidence-based, culturally-adapted, and implementable problem-solving intervention to reduce caregiver stress and burden and improve caregiver health and well-being. CONCLUSION: This work promotes inclusion of diverse and underserved populations and advances therapeutic behavioral interventions that improve the lives of caregivers of individuals with chronic conditions.


Subject(s)
Alzheimer Disease , Juniperus , Adult , Caregivers , Humans , Problem Solving , Randomized Controlled Trials as Topic , Research Design
2.
Childs Nerv Syst ; 34(4): 681-690, 2018 04.
Article in English | MEDLINE | ID: mdl-29230542

ABSTRACT

BACKGROUND: Cerebral edema peaks 36-72 h after moderate traumatic brain injury but thought to be uncommon after mild traumatic brain injury. Post-traumatic headache can develop 48-72 h post-injury, perhaps reflecting the developing cerebral edema. Pseudotumor cerebri can result from various causes, including cerebral edema, and is characterized by increased intracranial pressure, headache, visual, and other common symptoms. Our objective was to report a phenotypically identifiable post-traumatic headache subtype. CASE SERIES PRESENTATION: This case series of six pediatric patients with post-traumatic pseudotumor cerebri was assessed at 48-120 h post-primary injury with new or a change in symptoms such as headache, vision, auditory, balance, and cognition. Clinical findings included slight fever, neck/head pain, papilledema or cranial nerve deficit (6th), and lack of coordination. Elevated cerebral spinal fluid pressure was documented by lumbar puncture, with no infection. Symptoms improved with treatment specific to post-traumatic headache subtype (lumbar puncture, topiramate, or acetazolamide). CONCLUSIONS: Recognition of specific post-traumatic headache subtypes after mild traumatic brain injury will expedite treatment intervention to lower intracranial pressure and resolve symptoms.


Subject(s)
Brain Injuries, Traumatic/complications , Post-Traumatic Headache/etiology , Pseudotumor Cerebri/etiology , Adolescent , Brain Injuries, Traumatic/diagnostic imaging , Child , Female , Humans , Magnetic Resonance Angiography , Magnetic Resonance Imaging , Male , Neurologic Examination , Post-Traumatic Headache/diagnostic imaging , Pseudotumor Cerebri/diagnostic imaging
3.
J Perianesth Nurs ; 32(3): 219-224, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28527550

ABSTRACT

PURPOSE: On arrival to the postanesthesia care unit (PACU), patients are observed closely for significant neurological status changes. In particular, patients require frequent neurological examinations, which include assessment of the pupils for changes and/or abnormalities. DESIGN: This is a prospective, nonrandomized, observational study to examine the findings of pupillary examinations by nurses using different light sources in patients with existing pupillary assessments as ordered by standard of care. METHODS: PACU nurses were asked to perform their pupillary assessments using either a penlight with a gauge or a penlight without a gauge. Assessments were completed on the same patient within 5 minutes of one another, and results were compared. FINDINGS: PACU nurses using the same penlight with a gauge had more consistent results than those using different penlights without a gauge. CONCLUSIONS: Pupil assessments should be done with standardized light source.


Subject(s)
Postanesthesia Nursing/organization & administration , Pupil , Humans , Prospective Studies
4.
J Nurs Adm ; 46(12): 648-653, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27851706

ABSTRACT

OBJECTIVE: We hypothesized that nurses would benefit from the fellowship model traditionally used to engage physicians in clinical research. The Neuroscience Nursing Research Center (NNRC) fellowship program was created as a model for engaging nurses at all levels of clinical practice to become active in clinical research. BACKGROUND: The NNRC was established in 2013 as a novel approach to promote bedside nurses as primary investigators in clinical research. METHODS: The NNRC developed 4 pathways to nursing research success: research fellowship, student-nurse internship, didactic training, and research consultation. RESULTS: Fellows have enrolled more than 900 participants in 14 studies. Nurses have presented more than 20 abstracts at 12 conferences and submitted 11 manuscripts for publication. The NNRC has provided research training to more than 150 nurses. CONCLUSIONS: The NNRC program is successful in engaging nurses in research. It shows promise to continue to develop nursing research that is applicable to clinicians and thus improve patient care.


Subject(s)
Clinical Nursing Research/education , Neuroscience Nursing/education , Clinical Nursing Research/economics , Clinical Nursing Research/methods , Fellowships and Scholarships , Humans , Mentors , Neuroscience Nursing/economics , Neuroscience Nursing/methods , Research Support as Topic
5.
Crit Care Nurse ; 36(2): e1-7, 2016 Apr.
Article in English | MEDLINE | ID: mdl-27037347

ABSTRACT

Nurses caring for patients with acute stroke are likely to administer both music and medication with therapeutic intent. The administration of medication is based on accumulated scientific evidence and tailored to the needs of each patient. However, the therapeutic use of music is generally based on good intentions and anecdotal evidence. This review summarizes and examines the current literature regarding the effectiveness of music in the treatment of critically ill patients and the use of music in neurologically injured patients. The rationale for hypothesis-driven research to explore therapeutic music intervention in acute stroke is compelling.


Subject(s)
Critical Care Nursing/methods , Music Therapy , Stroke Rehabilitation/methods , Stroke/nursing , Adult , Aged , Aged, 80 and over , Education, Nursing, Continuing , Female , Humans , Male , Middle Aged
6.
Int Emerg Nurs ; 25: 48-52, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26360412

ABSTRACT

INTRODUCTION: The emergency department (ED) is demanding and high risk. The impact of sleep quantity has been hypothesized to impact patient care. This study investigated the hypothesis that fatigue and impaired mentation, due to sleep disturbance and shortened overall sleeping hours, would lead to increased nursing errors. METHODS: This is a prospective observational study of 30 ED nurses using self-administered survey and sleep architecture measured by wrist actigraphy as predictors of self-reported error rates. An actigraphy device was worn prior to working a 12-hour shift and nurses completed the Pittsburgh Sleep Quality Index (PSQI). Error rates were reported on a visual analog scale at the end of a 12-hour shift. RESULTS: The PSQI responses indicated that 73.3% of subjects had poor sleep quality. Lower sleep quality measured by actigraphy (hours asleep/hours in bed) was associated with higher self-perceived minor errors. Sleep quantity (total hours slept) was not associated with minor, moderate, nor severe errors. DISCUSSION: Our study found that ED nurses' sleep quality, immediately prior to a working 12-hour shift, is more predictive of error than sleep quantity. These results present evidence that a "good night's sleep" prior to working a nursing shift in the ED is beneficial for reducing minor errors.


Subject(s)
Fatigue/complications , Nurses/psychology , Nurses/standards , Research Design , Sleep , Adult , Emergency Service, Hospital , Female , Humans , Male , Prospective Studies , Surveys and Questionnaires , Workforce
7.
Channels (Austin) ; 8(3): 230-42, 2014.
Article in English | MEDLINE | ID: mdl-24476841

ABSTRACT

Dysregulated endoplasmic reticulum (ER) calcium (Ca(2+)) signaling is reported to play an important role in Alzheimer disease (AD) pathogenesis. The role of ER Ca(2+) release channels, the ryanodine receptors (RyanRs), has been extensivelys tudied in AD models and RyanR expression and activity are upregulated in the brains of various familial AD (FAD) models.The objective of this study was to utilize a genetic approach to evaluate the importance of RyanR type 3 (RyanR3) in the context of AD pathology.The expression of RyanR3 was also elevated in hippocampus of APPPS1 mice (Thy1-APPKM670/671NL, Thy1-PS1L166P).In young (≤ 3 mo) APPPS1 mice, the deletion of RyanR3 increased hippocampal neuronal network excitability and accelerated AD pathology, leading to mushroom spine loss and increased amyloid accumulation. In contrast, deletion of RyanR3 in older APPPS1 mice (≥ 6 mo) rescued network excitability and mushroom spine loss, reduced amyloid plaque load and reduced spontaneous seizure occurrence.Our data suggests a dual role for RyanR3 in AD pathology. In young AD neurons, RyanR3 protects AD neurons from synaptic and network dysfunction. In older AD neurons, increased RyanR3 activity contributes to pathology. These results imply that blockade of RyanR3 may be beneficial for those in the later stages of the disease, but RyanR activators may be beneficial when used prior to disease onset or in its initial stages. Caffeine is an activator of RyanRs and our results may help to explain a complex epidemiological connection between coffee consumption in mid-life and risk of AD development in old age.


Subject(s)
Alzheimer Disease/metabolism , Ryanodine Receptor Calcium Release Channel/metabolism , Alzheimer Disease/genetics , Amyloid beta-Peptides/metabolism , Animals , Disease Models, Animal , Hippocampus/metabolism , Humans , Mice , Mice, Inbred C57BL , Mice, Knockout , Neurons/metabolism , Ryanodine Receptor Calcium Release Channel/genetics
9.
Mol Neurodegener ; 6: 81, 2011 Nov 25.
Article in English | MEDLINE | ID: mdl-22118545

ABSTRACT

BACKGROUND: Huntington's disease (HD) is a progressive neurodegenerative disorder caused by a polyglutamine expansion in the Huntingtin protein which results in the selective degeneration of striatal medium spiny neurons (MSNs). Our group has previously demonstrated that calcium (Ca2+) signaling is abnormal in MSNs from the yeast artificial chromosome transgenic mouse model of HD (YAC128). Moreover, we demonstrated that deranged intracellular Ca2+ signaling sensitizes YAC128 MSNs to glutamate-induced excitotoxicity when compared to wild type (WT) MSNs. In previous studies we also observed abnormal neuronal Ca2+ signaling in neurons from spinocerebellar ataxia 2 (SCA2) and spinocerebellar ataxia 3 (SCA3) mouse models and demonstrated that treatment with dantrolene, a ryanodine receptor antagonist and clinically relevant Ca2+ signaling stabilizer, was neuroprotective in experiments with these mouse models. The aim of the current study was to evaluate potential beneficial effects of dantrolene in experiments with YAC128 HD mouse model. RESULTS: The application of caffeine and glutamate resulted in increased Ca2+ release from intracellular stores in YAC128 MSN cultures when compared to WT MSN cultures. Pre-treatment with dantrolene protected YAC128 MSNs from glutamate excitotoxicty, with an effective concentration of 100 nM and above. Feeding dantrolene (5 mg/kg) twice a week to YAC128 mice between 2 months and 11.5 months of age resulted in significantly improved performance in the beam-walking and gait-walking assays. Neuropathological analysis revealed that long-term dantrolene feeding to YAC128 mice significantly reduced the loss of NeuN-positive striatal neurons and reduced formation of Httexp nuclear aggregates. CONCLUSIONS: Our results support the hypothesis that deranged Ca2+ signaling plays an important role in HD pathology. Our data also implicate the RyanRs as a potential therapeutic target for the treatment of HD and demonstrate that RyanR inhibitors and Ca2+ signaling stabilizers such as dantrolene should be considered as potential therapeutics for the treatment of HD and other polyQ-expansion disorders.


Subject(s)
Dantrolene/pharmacology , Huntington Disease/physiopathology , Neurons/drug effects , Neuroprotective Agents/pharmacology , Animals , Apoptosis/drug effects , Caffeine/pharmacology , Calcium/metabolism , Calcium Signaling/physiology , Cells, Cultured , Central Nervous System Stimulants/pharmacology , Corpus Striatum/metabolism , Corpus Striatum/pathology , Dantrolene/therapeutic use , Disease Models, Animal , Glutamic Acid/toxicity , Huntington Disease/drug therapy , Huntington Disease/pathology , Mice , Mice, Transgenic , Motor Activity/drug effects , Muscle Relaxants, Central/pharmacology , Muscle Relaxants, Central/therapeutic use , Neurons/cytology , Neurons/metabolism , Neuroprotective Agents/therapeutic use
10.
Chem Biol ; 18(9): 1113-25, 2011 Sep 23.
Article in English | MEDLINE | ID: mdl-21944750

ABSTRACT

Polyglutamine(polyQ)-expanded proteins are potential therapeutic targets for the treatment of polyQ expansion disorders such as Huntington's disease (HD) and spinocerebellar ataxia type 3 (SCA3). Here, we used an amino-terminal fragment of a mutant Huntingtin protein (Htt-N-82Q) as bait in an unbiased screen of a 60,000 peptoid library. Peptoid HQP09 was selected from the isolated hits and confirmed as a specific ligand of Htt-N-82Q and Atxn3-77Q mutant proteins in biochemical experiments. We identified three critical residues in the HQP09 sequence that are important for its activity and generated a minimal derivative, HQP09_9, which maintains the specific polyQ-binding activity. We demonstrated that HQP09 and HQP09_9 inhibited aggregation of Htt-N-53Q in vitro and exerted Ca(2+)-stabilizing and neuroprotective effects in experiments with primary striatal neuronal cultures derived from HD mice. We further demonstrated that intracerebroventricular delivery of HQP09 to an HD mouse model resulted in reduced accumulation of mutant Huntingtin aggregates and improved motor behavioral outcomes. These results suggest that HQP09 and similar peptoids hold promise as novel therapeutics for developing treatments for HD, SCA3, and other polyglutamine expansion disorders.


Subject(s)
Huntington Disease/drug therapy , Neuroprotective Agents/chemistry , Peptides/metabolism , Peptoids/chemistry , Peptoids/therapeutic use , Animals , Cells, Cultured , Huntingtin Protein , Machado-Joseph Disease/drug therapy , Mice , Nerve Tissue Proteins/chemistry , Nerve Tissue Proteins/metabolism , Neurons/cytology , Neurons/drug effects , Neurons/metabolism , Neuroprotective Agents/pharmacology , Neuroprotective Agents/therapeutic use , Nuclear Proteins/chemistry , Nuclear Proteins/metabolism , Peptides/chemistry , Peptoids/pharmacology , Protein Binding
11.
Sci China Life Sci ; 54(8): 744-51, 2011 Aug.
Article in English | MEDLINE | ID: mdl-21786197

ABSTRACT

Alzheimer disease (AD) is the most common neurodegenerative disorder worldwide and is at present, incurable. The accumulation of toxic amyloid-beta (Aß) peptide aggregates in AD brain is thought to trigger the extensive synaptic loss and neurodegeneration linked to cognitive decline, an idea that underlies the 'amyloid hypothesis' of AD etiology in both the familal (FAD) and sporadic forms of the disease. Genetic mutations causing FAD also result in the dysregulation of neuronal calcium (Ca(2+)) handling and may contribute to AD pathogenesis, an idea termed the 'calcium hypothesis' of AD. Mutations in presenilin proteins account for majority of FAD cases. Presenilins function as catalytic subunit of γ-secretase involved in generation of Aß peptide Recently, we discovered that presenilns function as low-conductance, passive ER Ca(2+) leak channels, independent of γ-secretase activity. We further discovered that many FAD mutations in presenilins result in loss of ER Ca(2+) leak function activity and Ca(2+) overload in the ER. These results provided potential explanation for abnormal Ca(2+) signaling observed in FAD cells with mutations in presenilns. Our latest work on studies of ER Ca(2+) leak channel function of presenilins and implications of these findings for understanding AD pathogenesis are discussed in this article.


Subject(s)
Alzheimer Disease/physiopathology , Calcium Channels/metabolism , Calcium/metabolism , Endoplasmic Reticulum/metabolism , Presenilins/metabolism , Alzheimer Disease/genetics , Alzheimer Disease/pathology , Amyloid Precursor Protein Secretases/genetics , Amyloid Precursor Protein Secretases/metabolism , Amyloid beta-Peptides/genetics , Amyloid beta-Peptides/metabolism , Calcium Signaling/physiology , Humans , Models, Molecular , Mutation , Neurons/physiology , Presenilins/genetics , Protein Conformation
12.
Cell Calcium ; 50(3): 303-9, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21663966

ABSTRACT

Alzheimer's disease (AD) is the most common neurodegenerative disorder worldwide and is at present, incurable. The accumulation of toxic amyloid-beta (Aß) peptide aggregates in AD brain is thought to trigger the extensive synaptic loss and neurodegeneration linked to cognitive decline, an idea that underlies the 'amyloid hypothesis' of AD etiology in both the familal (FAD) and sporadic forms of the disease. Genetic mutations causing FAD also result in the dysregulation of neuronal calcium (Ca(2+)) handling and may contribute to AD pathogenesis, an idea termed the 'calcium hypothesis' of AD. Mutations in presenilin proteins account for the majority of FAD cases. Presenilins function as catalytic subunits of γ-secretase involved in the generation of Aß peptide. Recently, we discovered that presenilns function as low-conductance, passive ER Ca(2+) leak channels, independent of γ-secretase activity. We further discovered that many FAD mutations in presenilins results in the loss of ER Ca(2+) leak function activity and Ca(2+) overload in the ER. These results provided potential explanation for abnormal Ca(2+) signaling observed in FAD cells with mutations in presenilns. The implications of these findings for understanding AD pathogenesis are discussed in this article.


Subject(s)
Alzheimer Disease/metabolism , Calcium Channels/metabolism , Calcium/metabolism , Endoplasmic Reticulum/metabolism , Presenilins/physiology , Alzheimer Disease/genetics , Calcium Signaling/physiology , Humans , Mutation , Neurons/metabolism
13.
J Biol Chem ; 286(25): 22339-47, 2011 Jun 24.
Article in English | MEDLINE | ID: mdl-21531718

ABSTRACT

Missense mutations in presenilin 1 (PS1) and presenilin 2 (PS2) proteins are a major cause of familial Alzheimer disease. Presenilins are proteins with nine transmembrane (TM) domains that function as catalytic subunits of the γ-secretase complex responsible for the cleavage of the amyloid precursor protein and other type I transmembrane proteins. The water-filled cavity within presenilin is necessary to mediate the intramembrane proteolysis reaction. Consistent with this idea, cysteine-scanning mutagenesis and NMR studies revealed a number of water-accessible residues within TM7 and TM9 of mouse PS1. In addition to γ-secretase function, presenilins also demonstrate a low conductance endoplasmic reticulum Ca(2+) leak function, and many familial Alzheimer disease presenilin mutations impair this function. To map the potential Ca(2+) conductance pore in PS1, we systematically evaluated endoplasmic reticulum Ca(2+) leak activity supported by a series of cysteine point mutants in TM6, TM7, and TM9 of mouse PS1. The results indicate that TM7 and TM9, but not TM6, could play an important role in forming the conductance pore of PS1. These results are consistent with previous cysteine-scanning mutagenesis and NMR analyses of PS1 and provide further support for our hypothesis that the hydrophilic catalytic cavity of presenilins may also constitute a Ca(2+) conductance pore.


Subject(s)
Calcium/metabolism , Electric Conductivity , Mutagenesis , Presenilin-1/genetics , Presenilin-1/metabolism , Animals , Cell Line , Cell Membrane/metabolism , Cysteine , Endoplasmic Reticulum/metabolism , Hydrophobic and Hydrophilic Interactions , Mice , Mutation , Porosity , Presenilin-1/chemistry , Protein Structure, Tertiary
14.
J Alzheimers Dis ; 21(3): 781-93, 2010.
Article in English | MEDLINE | ID: mdl-20634584

ABSTRACT

Mutations in presenilins 1 and 2 (PS1 and PS2) are responsible for approximately 40% of all early onset familial Alzheimer's disease (FAD) monogenic cases. Presenilins (PSs) function as the catalytic subunit of γ-secretase and support cleavage of the amyloid-ß protein precursor (AßPP). We previously discovered that PSs also function as passive endoplasmic reticulum (ER) calcium (Ca2+) leak channels and that most FAD mutations in PSs affected their ER Ca2+ leak function. To further validate the relevance of our findings to human disease, we here performed Ca2+ imaging experiments with lymphoblasts established from FAD patients. We discovered that most FAD mutations in PSs disrupted ER Ca2+ leak function and resulted in increased ER Ca2+ pool in human lymphoblasts. However, we found that a subset of PS1 FAD mutants supported ER Ca2+ leak activity, as ER Ca2+ pool was unaffected in lymphoblasts. Most of the "functional" mutations for ER Ca2+ leak were clustered in the exon 8-9 area of PSEN1 gene and segregated with the cotton wool plaques and spastic paraparesis clinical phenotype occasionally observed in PS1 FAD patients. Our findings with the "functional" and "non-functional" PS1 FAD mutants were confirmed in Ca2+ rescue experiments with PS double-knockout mouse embryonic fibroblasts. Based on the combined effects of the PS1 FAD mutations on ER Ca2+ leak and γ-secretase activities we propose a model that explains the heterogeneity observed in FAD. The proposed model has implications for understanding the pathogenesis of both familial and sporadic AD.


Subject(s)
Alzheimer Disease/genetics , Calcium/metabolism , Endoplasmic Reticulum/metabolism , Presenilins/genetics , Alzheimer Disease/metabolism , Amyloid Precursor Protein Secretases/genetics , Amyloid Precursor Protein Secretases/metabolism , Analysis of Variance , Animals , Cell Line , Cells, Cultured , Endoplasmic Reticulum/genetics , Humans , Mice , Mice, Knockout , Mutation , Phenotype , Presenilins/metabolism
15.
J Alzheimers Dis ; 20 Suppl 2: S487-98, 2010.
Article in English | MEDLINE | ID: mdl-20413848

ABSTRACT

Alzheimer's disease (AD) is the most common neurodegenerative disorder among the aged worldwide. AD is characterized by extensive synaptic and neuronal loss that leads to impaired memory and cognitive decline. The cause of AD is not completely understood and no effective therapy has been developed. The accumulation of toxic amyloid-beta42 (Abeta42) peptide oligomers and aggregates in AD brain has been proposed to be primarily responsible for the pathology of the disease, an idea dubbed the 'amyloid hypothesis' of AD etiology. In addition to the increase in Abeta42 levels, disturbances in neuronal calcium (Ca2+) signaling and alterations in expression levels of Ca2+ signaling proteins have been observed in animal models of familial AD and in studies of postmortem brain samples from sporadic AD patients. Based on these data, the 'Ca2+ hypothesis of AD' has been proposed. In particular, familial AD has been linked with enhanced Ca2+ release from the endoplasmic reticulum and elevated cytosolic Ca2+ levels. The augmented cytosolic Ca2+ levels can trigger signaling cascades that affect synaptic stability and function and can be detrimental to neuronal health, such as activation of calcineurin and calpains. Here we review the latest results supporting the 'Ca2+ hypothesis' of AD pathogenesis. We further argue that over time, supranormal cytosolic Ca2+ signaling can impair mitochondrial function in AD neurons. We conclude that inhibitors and stabilizers of neuronal Ca2+ signaling and mitochondrial function may have therapeutic potential for AD treatment. We also discuss latest and planned AD therapeutic trials of agents targeting Ca2+ channels and mitochondria.


Subject(s)
Alzheimer Disease/pathology , Calcium Signaling/physiology , Mitochondrial Diseases/pathology , Neurons/metabolism , Alzheimer Disease/drug therapy , Alzheimer Disease/etiology , Animals , Calcium Channel Blockers/therapeutic use , Humans , Mitochondrial Diseases/complications , Mitochondrial Diseases/drug therapy , Models, Biological
16.
Cell Calcium ; 47(2): 183-9, 2010 Feb.
Article in English | MEDLINE | ID: mdl-20080301

ABSTRACT

Alzheimer disease (AD) is the most common neurodegenerative disorder worldwide and is at present, incurable. The accumulation of toxic amyloid-beta (Abeta) peptide aggregates in AD brain are thought to trigger the extensive synaptic loss and neurodegeneration linked to cognitive decline, an idea that underlies the 'amyloid hypothesis' of AD etiology in both the familal (FAD) and sporadic forms of the disease. Mutations causing FAD also result in the dysregulation of neuronal calcium (Ca2+) handling and may contribute to AD pathogenesis, an idea termed the 'calcium hypothesis' of AD. In particular, Ca2+ dysregulation by the endoplasmic reticulum (ER) in AD mouse models results in augmented cytosolic Ca2+ levels which can trigger signalling cascades that are detrimental to neuronal function and health. However, there is growing evidence to suggest that not all forms of Ca2+ dysregulation in AD neurons are harmful and some of them instead may be compensatory. These changes may help modulate neuronal excitability and slow AD pathology, especially in the early stages of the disease. Clearly, a better understanding of how dysregulation of neuronal Ca2+ handling contributes to neurodegeneration and neuroprotection in AD is needed as Ca2+ signalling modulators are targets of great interest as potential AD therapeutics.


Subject(s)
Alzheimer Disease/metabolism , Calcium Channels/metabolism , Calcium Signaling , Calcium/metabolism , Neurons/metabolism , Alzheimer Disease/drug therapy , Alzheimer Disease/genetics , Alzheimer Disease/pathology , Amyloid/genetics , Amyloid/metabolism , Animals , Apoptosis , Calcium Channels/genetics , Electron Transport , Endoplasmic Reticulum/metabolism , Humans , Memantine/therapeutic use , Mice , Mutation/genetics , Neurons/pathology , Synaptic Transmission
17.
J Neurochem ; 112(2): 356-65, 2010 Jan.
Article in English | MEDLINE | ID: mdl-19903243

ABSTRACT

The cellular pathology of Alzheimer's disease is progressive and protracted leading eventually to considerable neuronal death. The underlying mechanisms of the pathology are complex but changes in the control of intracellular Ca2+ are believed to contribute to the demise of neurons. In this study, we investigated the functional consequences of an increase in the expression of the type 3 isoform of the ryanodine receptor (RyR3). We found that although cortical neurons from TgCRND8 mice secreted significantly more amyloid beta protein and showed significantly increased RyR3 expression, they were no more sensitive to cell stress than non-transgenic neurons. Furthermore, despite increased intracellular Ca2+ release in response to ryanodine, we found that basal Ca2+, K+-evoked Ca2+ responses, and capacitative Ca2+ entry were no different in TgCRND8 neurons compared with non-transgenic neurons. Therefore, as RyR3 up-regulation did not affect neuronal health or global Ca2+ homeostasis, we investigated the effect of reducing RyR3 expression using small interfering RNA. Surprisingly, a reduction of RyR3 expression in TgCRND8, but not in non-transgenic, neurons increased neuronal death. These data reveal a new role for RyR3 and indicate a novel potential therapeutic target to delay or prevent the progression of Alzheimer's disease.


Subject(s)
Alzheimer Disease/metabolism , Neurons/metabolism , Ryanodine Receptor Calcium Release Channel/metabolism , Up-Regulation/genetics , Alzheimer Disease/genetics , Alzheimer Disease/pathology , Amyloid beta-Peptides/metabolism , Amyloid beta-Protein Precursor/genetics , Animals , Calcium/metabolism , Cell Death/drug effects , Cells, Cultured , Cerebral Cortex/cytology , Disease Models, Animal , Dose-Response Relationship, Drug , Enzyme-Linked Immunosorbent Assay/methods , Glutamic Acid/pharmacology , Green Fluorescent Proteins/genetics , Humans , Mice , Mice, Transgenic , Mutation/genetics , Neurons/drug effects , Peptide Fragments/metabolism , Phosphopyruvate Hydratase/metabolism , Potassium/pharmacology , Presenilin-1/genetics , RNA, Messenger/metabolism , RNA, Small Interfering/pharmacology , Ryanodine Receptor Calcium Release Channel/genetics , Tetrazolium Salts , Thiazoles , Up-Regulation/drug effects
18.
J Biol Chem ; 281(50): 38440-7, 2006 Dec 15.
Article in English | MEDLINE | ID: mdl-17050533

ABSTRACT

Disruption of intracellular calcium homeostasis precedes the neurodegeneration that occurs in Alzheimer disease (AD). Of the many neuronal calcium-regulating proteins, we focused on endoplasmic reticulum (ER)-resident ryanodine receptors (RyRs) because they are increased in the hippocampus of mice expressing mutant presenilin-1 and are associated with neurotoxicity. Others have observed that ryanodine binding is elevated in human postmortem hippocampal regions suggesting that RyR(s) are involved in AD pathogenesis. Here we report that extracellular amyloid-beta(Abeta)-(1-42) specifically increased RyR-3, but not RyR-1 or RyR-2, gene expression in cortical neurons from C57Bl6 mice. Furthermore, endogenously produced Abeta-(1-42) increased RyR-3 mRNA and protein in cortical neurons from transgenic (Tg)CRND8 mice, a mouse model of AD. Increased RyR-3 mRNA and protein was also observed in brain tissue from 4- to 4.5-month-old Tg animals compared with non-Tg littermate controls. In experiments performed in nominal extracellular calcium, neurons from Tg mice had significant increases in intracellular calcium following ryanodine or glutamate treatment compared with littermate controls, which was abolished by treatment with small interfering RNA directed to RyR-3, indicating that the higher levels of calcium originated from RyR-3-regulated stores. Taken together, these observations suggest that Abeta-(1-42)-mediated changes in intracellular calcium homeostasis is regulated in part through a direct increase of RyR-3 expression and function.


Subject(s)
Amyloid beta-Peptides/pharmacology , Neurons/physiology , Peptide Fragments/pharmacology , Ryanodine Receptor Calcium Release Channel/drug effects , Alzheimer Disease/physiopathology , Animals , Base Sequence , Calcium/metabolism , DNA Primers , Endoplasmic Reticulum/metabolism , Mice , Mice, Transgenic , Neurons/metabolism , RNA, Messenger/genetics , Ryanodine Receptor Calcium Release Channel/genetics , Ryanodine Receptor Calcium Release Channel/physiology
SELECTION OF CITATIONS
SEARCH DETAIL
...