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Moiz A, Levett JY, Filion KB, Peri K, Reynier P, Eisenberg MJ. Long-Term Efficacy and Safety of Once-Weekly Semaglutide for Weight Loss in Patients Without Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Am J Cardiol 2024:S0002-9149(24)00319-9. [PMID: 38679221 DOI: 10.1016/j.amjcard.2024.04.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 04/15/2024] [Accepted: 04/19/2024] [Indexed: 05/01/2024]
Abstract
Semaglutide, a glucagon-like peptide-1 receptor agonist, has demonstrated clinically important weight loss effects in patients with type 2 diabetes. However, its effects on sustained weight loss among individuals without diabetes remains unclear. Our objective was to examine the long-term efficacy and safety of semaglutide use for weight loss among individuals with overweight/obesity and without diabetes. MEDLINE, Embase, and the Cochrane Libraries were systematically searched to identify randomized controlled trials (RCTs) that randomized participants with overweight/obesity but without diabetes to once-weekly 2.4 mg subcutaneous semaglutide versus placebo with follow-up of at least 68 weeks. The primary outcome was change in relative body weight from baseline to longest follow-up. Random-effects models with inverse variance weighting were used to estimate weighted mean differences (WMDs) and relative risks (RRs) with 95% confidence intervals (CIs). A total of 4 RCTs (n=3,087) were included. Of the 3 trials which provided BMI by category (n=2,783), 94.0% of participants had a baseline BMI ≥30 kg/m2. Compared to placebo, use of semaglutide was associated with substantial decreases in long-term relative (WMD: -12.1%; 95% CI -13.5, -10.7) and absolute body weight (WMD: -12.3 kg; 95% CI -13.6, -11.0). At longest follow-up, 33.4% of participants randomized to semaglutide achieved ≥20% weight loss compared to 2.2% with placebo (RR: 15.08; 95% CI 9.31, 24.43). The risk of gastrointestinal adverse events was higher among semaglutide participants than placebo (RR: 1:47; 95% CI 1.28, 1.68); however, the majority of these events were transient, mild-to-moderate in severity, and did not require treatment discontinuation. In conclusion, semaglutide is efficacious for sustained weight loss among individuals with overweight/obesity and without diabetes.
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Affiliation(s)
- Areesha Moiz
- Centre for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital/McGill University, Montreal, Canada
| | - Jeremy Y Levett
- Centre for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital/McGill University, Montreal, Canada; Faculty of Medicine and Health Sciences, McGill University, Montreal, Canada
| | - Kristian B Filion
- Centre for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital/McGill University, Montreal, Canada; Faculty of Medicine and Health Sciences, McGill University, Montreal, Canada; Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Canada; Department of Medicine, McGill University, Montreal, Canada
| | - Katya Peri
- Centre for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital/McGill University, Montreal, Canada; Faculty of Medicine and Health Sciences, McGill University, Montreal, Canada
| | - Pauline Reynier
- Centre for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital/McGill University, Montreal, Canada
| | - Mark J Eisenberg
- Centre for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital/McGill University, Montreal, Canada; Faculty of Medicine and Health Sciences, McGill University, Montreal, Canada; Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Canada; Department of Medicine, McGill University, Montreal, Canada; Division of Cardiology, Jewish General Hospital/McGill University, Montreal, Canada.
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Yang SK, Kubo S, Black CS, Peri K, Dai D, Legal T, Valente-Paterno M, Gaertig J, Bui KH. Effect of α-tubulin acetylation on the doublet microtubule structure. eLife 2024; 12:RP92219. [PMID: 38598282 PMCID: PMC11006419 DOI: 10.7554/elife.92219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024] Open
Abstract
Acetylation of α-tubulin at the lysine 40 residue (αK40) by αTAT1/MEC-17 acetyltransferase modulates microtubule properties and occurs in most eukaryotic cells. Previous literatures suggest that acetylated microtubules are more stable and damage resistant. αK40 acetylation is the only known microtubule luminal post-translational modification site. The luminal location suggests that the modification tunes the lateral interaction of protofilaments inside the microtubule. In this study, we examined the effect of tubulin acetylation on the doublet microtubule (DMT) in the cilia of Tetrahymena thermophila using a combination of cryo-electron microscopy, molecular dynamics, and mass spectrometry. We found that αK40 acetylation exerts a small-scale effect on the DMT structure and stability by influencing the lateral rotational angle. In addition, comparative mass spectrometry revealed a link between αK40 acetylation and phosphorylation in cilia.
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Affiliation(s)
- Shun Kai Yang
- Department of Anatomy and Cell Biology, McGill UniversityMontréalCanada
| | - Shintaroh Kubo
- Department of Anatomy and Cell Biology, McGill UniversityMontréalCanada
| | | | - Katya Peri
- Department of Anatomy and Cell Biology, McGill UniversityMontréalCanada
| | - Daniel Dai
- Department of Anatomy and Cell Biology, McGill UniversityMontréalCanada
| | - Thibault Legal
- Department of Anatomy and Cell Biology, McGill UniversityMontréalCanada
| | | | - Jacek Gaertig
- Department of Cellular Biology, University of GeorgiaAthensUnited States
| | - Khanh Huy Bui
- Department of Anatomy and Cell Biology, McGill UniversityMontréalCanada
- Centre de Recherche en Biologie Structurale, McGill UniversityMontréalCanada
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Peri K, Honeycutt L, Wennberg E, Windle SB, Filion KB, Gore G, Kudrina I, Paraskevopoulos E, Moiz A, Martel MO, Eisenberg MJ. Efficacy of interventions targeted at physician prescribers of opioids for chronic non-cancer pain: an overview of systematic reviews. BMC Med 2024; 22:76. [PMID: 38378544 PMCID: PMC10877926 DOI: 10.1186/s12916-024-03287-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 02/07/2024] [Indexed: 02/22/2024] Open
Abstract
BACKGROUND To combat the opioid crisis, interventions targeting the opioid prescribing behaviour of physicians involved in the management of patients with chronic non-cancer pain (CNCP) have been introduced in clinical settings. An integrative synthesis of systematic review evidence is required to better understand the effects of these interventions. Our objective was to synthesize the systematic review evidence on the effect of interventions targeting the behaviours of physician opioid prescribers for CNCP among adults on patient and population health and prescriber behaviour. METHODS We searched MEDLINE, Embase, and PsycInfo via Ovid; the Cochrane Database of Systematic Reviews; and Epistemonikos. We included systematic reviews that evaluate any type of intervention aimed at impacting opioid prescriber behaviour for adult CNCP in an outpatient setting. RESULTS We identified three full texts for our review that contained 68 unique primary studies. The main interventions we evaluated were structured prescriber education (one review) and prescription drug monitoring programmes (PDMPs) (two reviews). Due to the paucity of data available, we could not determine with certainty that education interventions improved outcomes in deprescribing. There is some evidence that PDMPs decrease the number of adverse opioid-related events, increase communication among healthcare workers and patients, modify healthcare practitioners' approach towards their opioid prescribed patients, and offer more chances for education and counselling. CONCLUSIONS Our overview explores the possibility of PDMPs as an opioid deprescribing intervention and highlights the need for more high-quality primary research on this topic.
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Affiliation(s)
- Katya Peri
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada
- Department of Medicine, McGill University, Montreal, QC, Canada
| | - Lucy Honeycutt
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada
| | - Erica Wennberg
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada
- Temerty Faculty of Medicine and Institute of Health Policy, Management and Evaluation, Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
| | - Sarah B Windle
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada
- Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada
| | - Kristian B Filion
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada
- Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada
- Department of Medicine, McGill University, Montreal, QC, Canada
| | - Genevieve Gore
- Schulich Library of Science and Engineering, McGill University, Montreal, QC, Canada
| | - Irina Kudrina
- Departments of Family Medicine and of Anesthesia, McGill University, Montreal, QC, Canada
| | - Elena Paraskevopoulos
- Departments of Family Medicine, Royal Ottawa Mental Health Center and Queensway Carleton Hospital, Ottawa, ON, Canada
| | - Areesha Moiz
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada
| | - Marc O Martel
- Faculty of Dentistry and Department of Anesthesia, McGill University, Montreal, QC, Canada
| | - Mark J Eisenberg
- Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada.
- Department of Medicine, McGill University, Montreal, QC, Canada.
- Division of Cardiology, Jewish General Hospital, Jewish General Hospital, McGill University, 3755 Cote Ste-Catherine Road, Suite H-421, Montreal, QC, H3T 1E2, Canada.
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Peri K, Eisenberg MJ. Evaluating non-cognitive skills in medical school applicants. BMC Med Educ 2024; 24:82. [PMID: 38263009 PMCID: PMC10804460 DOI: 10.1186/s12909-024-05046-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 01/09/2024] [Indexed: 01/25/2024]
Abstract
Medical school candidates must have both the cognitive and professional competencies required to become good physicians. In this commentary, we outline the evidence and outcomes associated with the implementation of these selection methodologies and evaluate their ability to assess non-cognitive skills.
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Affiliation(s)
- Katya Peri
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada
| | - Mark J Eisenberg
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada.
- Departments of Medicine and of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada.
- Division of Cardiology, Jewish General Hospital, McGill University, 3755 Côte Ste-Catherine Road, Suite H-421.1, H3T 1E2, Montreal, QC, Canada.
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Kubo S, Black CS, Joachimiak E, Yang SK, Legal T, Peri K, Khalifa AAZ, Ghanaeian A, McCafferty CL, Valente-Paterno M, De Bellis C, Huynh PM, Fan Z, Marcotte EM, Wloga D, Bui KH. Native doublet microtubules from Tetrahymena thermophila reveal the importance of outer junction proteins. Nat Commun 2023; 14:2168. [PMID: 37061538 PMCID: PMC10105768 DOI: 10.1038/s41467-023-37868-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 04/03/2023] [Indexed: 04/17/2023] Open
Abstract
Cilia are ubiquitous eukaryotic organelles responsible for cellular motility and sensory functions. The ciliary axoneme is a microtubule-based cytoskeleton consisting of two central singlets and nine outer doublet microtubules. Cryo-electron microscopy-based studies have revealed a complex network inside the lumen of both tubules composed of microtubule-inner proteins (MIPs). However, the functions of most MIPs remain unknown. Here, we present single-particle cryo-EM-based analyses of the Tetrahymena thermophila native doublet microtubule and identify 42 MIPs. These data shed light on the evolutionarily conserved and diversified roles of MIPs. In addition, we identified MIPs potentially responsible for the assembly and stability of the doublet outer junction. Knockout of the evolutionarily conserved outer junction component CFAP77 moderately diminishes Tetrahymena swimming speed and beat frequency, indicating the important role of CFAP77 and outer junction stability in cilia beating generation and/or regulation.
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Affiliation(s)
- Shintaroh Kubo
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Corbin S Black
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland
| | - Shun Kai Yang
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Thibault Legal
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Katya Peri
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Ahmad Abdelzaher Zaki Khalifa
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Avrin Ghanaeian
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Caitlyn L McCafferty
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, TX, 78712, USA
| | - Melissa Valente-Paterno
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Chelsea De Bellis
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
| | - Phuong M Huynh
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
| | - Zhe Fan
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
| | - Edward M Marcotte
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, TX, 78712, USA
| | - Dorota Wloga
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland.
| | - Khanh Huy Bui
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada.
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada.
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Black C, Dai DC, Peri K, Ichikawa M, Bui KH. Preparation of Doublet Microtubule Fraction for Single ParticleCryo-electron Microscopy. Bio Protoc 2021; 11:e4041. [PMID: 34250207 PMCID: PMC8249912 DOI: 10.21769/bioprotoc.4041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 02/03/2021] [Accepted: 02/08/2021] [Indexed: 11/02/2022] Open
Abstract
Over the years, studying the ultrastructure of the eukaryotic cilia/flagella using electron microscopy (EM) has contributed significantly toward our understanding of ciliary function. Major complexes in the cilia, such as inner and outer dynein arms, radial spokes, and dynein regulatory complexes, were originally discovered by EM. Classical resin-embedding EM or cryo-electron tomography can be performed directly on the isolated cilia or in some cases, cilia directly attached to the cell body. Recently, single particle cryo-EM has emerged as a powerful structural technique to elucidate high-resolution structures of macromolecular complexes; however, single particle cryo-EM requires non-overlapping complexes, i.e., the doublet microtubule of the cilia. Here, we present a protocol to separate the doublet microtubule from the isolated cilia bundle of two species, Tetrahymena thermophila and Chlamydomonas reinhardtii, using ATP reactivation and sonication. Our approach produces good distribution and random orientation of the doublet microtubule fragments, which is suitable for single particle cryo-EM analysis.
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Affiliation(s)
- Corbin Black
- Department of Anatomy and Cell Biology, McGill University, Montréal, Canada
| | - Daniel Chen Dai
- Department of Anatomy and Cell Biology, McGill University, Montréal, Canada
| | - Katya Peri
- Department of Anatomy and Cell Biology, McGill University, Montréal, Canada
| | - Muneyoshi Ichikawa
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Takayama-cho, Ikoma, Nara, Japan
- PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
| | - Khanh Huy Bui
- Department of Anatomy and Cell Biology, McGill University, Montréal, Canada
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Parsons J, Waters DL, Binns E, Burholt V, Cheung G, Clare S, Duncan R, Fox C, Gibson R, Grant A, Guy G, Jackson T, Kerse N, Logan R, Peri K, Petagna C, Stephens F, Taylor D, Teh R, Wall C. Letter to the Editor: Healthy for Life: An Innovative and Collaborative Approach to COVID 19 Lockdown in New Zealand. J Frailty Aging 2020; 10:72. [PMID: 33331626 PMCID: PMC7782046 DOI: 10.14283/jfa.2020.49] [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] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Recently Boreskie and colleagues published an editorial in the Journal of Frailty and Aging on Preventing Frailty Progression During the COVID-19 Pandemic (1). In it they proposed the SAVE programme (Socialization, Adequate nutrition, Vitamin D, Exercise) to prevent frailty. They concluded that creative thinking and concerted efforts would be needed to disseminate health recommendations to maintain the health of pre-frail and frail older adults in unprecedented times, such as those posed by the COVID-19 pandemic.
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Affiliation(s)
- J Parsons
- A/Prof John Parsons Faculty of Medicine and Health Sciences, University of Auckland, Auckland, New Zealand. Email
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Peri K, Broad JB, Hikaka J, Boyd M, Bloomfield K, Wu Z, Calvert C, Tatton A, Higgins AM, Bramley D, Connolly MJ. Study protocol: older people in retirement villages. A survey and randomised trial of a multi-disciplinary invention designed to avoid adverse outcomes. BMC Geriatr 2020; 20:247. [PMID: 32680465 PMCID: PMC7367387 DOI: 10.1186/s12877-020-01640-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Accepted: 07/03/2020] [Indexed: 12/02/2022] Open
Abstract
Background There is increasing interest among older people in moving into retirement villages (RVs), an attractive option for those seeking a supportive community as they age, while still maintaining independence. Currently in New Zealand there is limited knowledge of the medical, service supports, social status and needs of RV residents. The objective of this study is to explore RV facilities and services, the health and functional status of RV residents, prospectively study their healthcare trajectories and to implement a multidisciplinary team intervention to potentially decrease dependency and impact healthcare utilization. Methods All RVs located in two large district health boards in Auckland, New Zealand were eligible to participate. This three-year project comprised three phases: The survey phase provided a description of RVs, residents’ characteristics and health and functional status. RV managers completed a survey of size, facilities and recreational and healthcare services provided in the village. Residents were surveyed to establish reasons for entry to the village and underwent a Gerontology Nurse Specialist (GNS) assessment providing details of demographics, social engagement, health and functional status. The cohort study phase examines residents’ healthcare trajectories and adverse outcomes, over three years. The final phase is a randomised controlled trial of a multidisciplinary team intervention aimed to improve health outcomes for more vulnerable residents. Residents who triggered potential unmet health needs during the assessment in the survey phase were randomised to intervention or usual care groups. Multidisciplinary team meetings included the resident and support person, a geriatrician or gerontology nurse practitioner, GNS, pharmacist and General Practitioner. The primary outcome of the randomised controlled trial will be first acute hospitalization. Secondary outcomes include all acute hospitalizations, long-term care admissions, and all-cause mortality. Discussion This paper describes the study protocol of this complex study. The study aims to inform policies and practices around health care services for residents in retirement villages. The results of this trial are expected early 2020 with publication subsequently. Trial registration Australia and New Zealand Clinical Trials Registry: ACTRN12616000685415. Registered 25.5.2016. Universal Trial Number (UTN): U111–1173-6083.
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Affiliation(s)
- K Peri
- School of Nursing, University of Auckland, Private Bag 92 019, Auckland, 1142, New Zealand
| | - J B Broad
- Department of Geriatric Medicine, University of Auckland, Level 1, Building 5, Waitemata District Health Board, PO Box 93 503, Auckland, Takapuna, 0740, New Zealand
| | - J Hikaka
- Waitemata District Health Board, PO Box 93 503, Auckland, Takapuna, 0740, New Zealand
| | - M Boyd
- School of Nursing, University of Auckland, Private Bag 92 019, Auckland, 1142, New Zealand.,Department of Geriatric Medicine, University of Auckland, Level 1, Building 5, Waitemata District Health Board, PO Box 93 503, Auckland, Takapuna, 0740, New Zealand
| | - K Bloomfield
- Department of Geriatric Medicine, University of Auckland, Level 1, Building 5, Waitemata District Health Board, PO Box 93 503, Auckland, Takapuna, 0740, New Zealand.,Waitemata District Health Board, PO Box 93 503, Auckland, Takapuna, 0740, New Zealand
| | - Z Wu
- Department of Geriatric Medicine, University of Auckland, Level 1, Building 5, Waitemata District Health Board, PO Box 93 503, Auckland, Takapuna, 0740, New Zealand
| | - C Calvert
- Department of Geriatric Medicine, University of Auckland, Level 1, Building 5, Waitemata District Health Board, PO Box 93 503, Auckland, Takapuna, 0740, New Zealand.,Auckland District Health Board, Private Bag 92 024, Auckland Mail Centre, Auckland, 1142, New Zealand
| | - A Tatton
- Department of Geriatric Medicine, University of Auckland, Level 1, Building 5, Waitemata District Health Board, PO Box 93 503, Auckland, Takapuna, 0740, New Zealand.,Waitemata District Health Board, PO Box 93 503, Auckland, Takapuna, 0740, New Zealand
| | - A-M Higgins
- Department of Geriatric Medicine, University of Auckland, Level 1, Building 5, Waitemata District Health Board, PO Box 93 503, Auckland, Takapuna, 0740, New Zealand
| | - D Bramley
- Waitemata District Health Board, PO Box 93 503, Auckland, Takapuna, 0740, New Zealand
| | - M J Connolly
- Department of Geriatric Medicine, University of Auckland, Level 1, Building 5, Waitemata District Health Board, PO Box 93 503, Auckland, Takapuna, 0740, New Zealand. .,Waitemata District Health Board, PO Box 93 503, Auckland, Takapuna, 0740, New Zealand.
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Dai D, Ichikawa M, Peri K, Rebinsky R, Huy Bui K. Identification and mapping of central pair proteins by proteomic analysis. Biophys Physicobiol 2020; 17:71-85. [PMID: 33178545 PMCID: PMC7596323 DOI: 10.2142/biophysico.bsj-2019048] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [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: 09/20/2019] [Accepted: 06/10/2020] [Indexed: 01/07/2023] Open
Abstract
Cilia or flagella of eukaryotes are small micro-hair like structures that are indispensable to single-cell motility and play an important role in mammalian biological processes. Cilia or flagella are composed of nine doublet microtubules surrounding a pair of singlet microtubules called the central pair (CP). Together, this arrangement forms a canonical and highly conserved 9+2 axonemal structure. The CP, which is a unique structure exclusive to motile cilia, is a pair of structurally dimorphic singlet microtubules decorated with numerous associated proteins. Mutations of CP-associated proteins cause several different physical symptoms termed as ciliopathies. Thus, it is crucial to understand the architecture of the CP. However, the protein composition of the CP was poorly understood. This was because the traditional method of identification of CP proteins was mostly limited by available Chlamydomonas mutants of CP proteins. Recently, more CP protein candidates were presented based on mass spectrometry results, but most of these proteins were not validated. In this study, we re-evaluated the CP proteins by conducting a similar comprehensive CP proteome analysis comparing the mass spectrometry results of the axoneme sample prepared from Chlamydomonas strains with and without CP complex. We identified a similar set of CP protein candidates and additional new 11 CP protein candidates. Furthermore, by using Chlamydomonas strains lacking specific CP sub-structures, we present a more complete model of localization for these CP proteins. This work has established a new foundation for understanding the function of the CP complex in future studies.
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Affiliation(s)
- Daniel Dai
- Department of Anatomy and Cell Biology, McGill University, Montréal, Québec H3A 0C7, Canada
| | - Muneyoshi Ichikawa
- Department of Systems Biology, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Katya Peri
- Department of Anatomy and Cell Biology, McGill University, Montréal, Québec H3A 0C7, Canada
| | - Reid Rebinsky
- Department of Anatomy and Cell Biology, McGill University, Montréal, Québec H3A 0C7, Canada
| | - Khanh Huy Bui
- Department of Anatomy and Cell Biology, McGill University, Montréal, Québec H3A 0C7, Canada
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Ferguson C, Thomson W, Smith M, Kerse N, Peri K, Gribben B. Medication taking in a national sample of dependent older people. Res Social Adm Pharm 2020; 16:299-307. [DOI: 10.1016/j.sapharm.2019.05.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 05/01/2019] [Accepted: 05/19/2019] [Indexed: 01/17/2023]
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Khalifa A, Ichikawa M, Dai D, Black C, Peri K, McAlear T, Kubo S, Veyron S, Kai Yang S, Basu K, Vargas J, Trempe JF, Bechstedt S, Huy Bui K. The Inner Junction Complex of the Cilia is an Interaction Hub that Involves Tubulin Post-translational Modifications. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Khalifa AAZ, Ichikawa M, Dai D, Kubo S, Black CS, Peri K, McAlear TS, Veyron S, Yang SK, Vargas J, Bechstedt S, Trempe JF, Bui KH. The inner junction complex of the cilia is an interaction hub that involves tubulin post-translational modifications. eLife 2020; 9:e52760. [PMID: 31951202 PMCID: PMC6994238 DOI: 10.7554/elife.52760] [Citation(s) in RCA: 173] [Impact Index Per Article: 43.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 01/16/2020] [Indexed: 12/11/2022] Open
Abstract
Microtubules are cytoskeletal structures involved in stability, transport and organization in the cell. The building blocks, the α- and β-tubulin heterodimers, form protofilaments that associate laterally into the hollow microtubule. Microtubule also exists as highly stable doublet microtubules in the cilia where stability is needed for ciliary beating and function. The doublet microtubule maintains its stability through interactions at its inner and outer junctions where its A- and B-tubules meet. Here, using cryo-electron microscopy, bioinformatics and mass spectrometry of the doublets of Chlamydomonas reinhardtii and Tetrahymena thermophila, we identified two new inner junction proteins, FAP276 and FAP106, and an inner junction-associated protein, FAP126, thus presenting the complete answer to the inner junction identity and localization. Our structural study of the doublets shows that the inner junction serves as an interaction hub that involves tubulin post-translational modifications. These interactions contribute to the stability of the doublet and hence, normal ciliary motility.
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Affiliation(s)
- Ahmad Abdelzaher Zaki Khalifa
- Department of Anatomy and Cell BiologyMcGill UniversityQuébecCanada
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
| | | | - Daniel Dai
- Department of Anatomy and Cell BiologyMcGill UniversityQuébecCanada
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
| | - Shintaroh Kubo
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
- Department of Biophysics, Graduate School of ScienceKyoto UniversityKyotoJapan
| | - Corbin Steven Black
- Department of Anatomy and Cell BiologyMcGill UniversityQuébecCanada
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
| | - Katya Peri
- Department of Anatomy and Cell BiologyMcGill UniversityQuébecCanada
| | - Thomas S McAlear
- Department of Anatomy and Cell BiologyMcGill UniversityQuébecCanada
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
| | - Simon Veyron
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
- Department of Pharmacology & TherapeuticsMcGill UniversityMontréalCanada
| | - Shun Kai Yang
- Department of Anatomy and Cell BiologyMcGill UniversityQuébecCanada
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
| | - Javier Vargas
- Department of Anatomy and Cell BiologyMcGill UniversityQuébecCanada
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
| | - Susanne Bechstedt
- Department of Anatomy and Cell BiologyMcGill UniversityQuébecCanada
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
| | - Jean-François Trempe
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
- Department of Pharmacology & TherapeuticsMcGill UniversityMontréalCanada
| | - Khanh Huy Bui
- Department of Anatomy and Cell BiologyMcGill UniversityQuébecCanada
- Centre de Recherche en Biologie Structurale - FRQSMcGill UniversityQuébecCanada
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13
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Connolly MJ, Hikaka J, Bloomfield K, Broad JB, Wu Z, Boyd M, Peri K, Calvert C, Tatton A, Higgins AM, Bramley D. 83RESEARCH IN THE RETIREMENT VILLAGE COMMUNITY: DOES THE RECRUITED SAMPLE REFLECT THE RESIDENT POPULATION? Age Ageing 2019. [DOI: 10.1093/ageing/afz061.04] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- M J Connolly
- Department of Geriatric Medicine, University of Auckland, Takapuna, New Zealand
- Waitemata District Health Board, Auckland, New Zealand
| | - J Hikaka
- Waitemata District Health Board, Auckland, New Zealand
| | - K Bloomfield
- Department of Geriatric Medicine, University of Auckland, Takapuna, New Zealand
- Waitemata District Health Board, Auckland, New Zealand
| | - J B Broad
- Department of Geriatric Medicine, University of Auckland, Takapuna, New Zealand
| | - Z Wu
- Department of Geriatric Medicine, University of Auckland, Takapuna, New Zealand
| | - M Boyd
- School of Nursing, University of Auckland, Grafton, New Zealand
| | - K Peri
- School of Nursing, University of Auckland, Grafton, New Zealand
| | - C Calvert
- Department of Geriatric Medicine, University of Auckland, Takapuna, New Zealand
- Auckland District Health Board, Auckland, New Zealand
| | - A Tatton
- Department of Geriatric Medicine, University of Auckland, Takapuna, New Zealand
- Waitemata District Health Board, Auckland, New Zealand
| | - A -M Higgins
- Department of Geriatric Medicine, University of Auckland, Takapuna, New Zealand
| | - D Bramley
- Waitemata District Health Board, Auckland, New Zealand
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Abstract
OBJECTIVES To determine the nutrition risk status and factors associated with nutrition risk among older adults enrolled in the Brief Risk Identification Geriatric Health Tool (BRIGHT Trial). DESIGN A cluster randomised controlled trial. SETTING Three main centres in New Zealand. PARTICIPANTS A total of 3,893 older adults were recruited from 60 general practices in three of the District Health Board (DHB) regions aged 75 years and older (or 65 years and older if Māori). MEASUREMENTS Nutrition risk was assessed using the Australian Nutrition Screening Initiative (ANSI). Validated questionnaires were used to establish quality of life (WHOQOL-BREF), physical function (the Nottingham Extended Activities of Daily Living) and depressive symptoms (15 item Geriatric Depression Scale). Demographic, standard of living and health data were established. RESULTS Sixty two percent of participants were identified to be at moderate or high nutrition risk. The mean ANSI score was 4.9 (range 0-21, maximum 29). Factors which independently predicted moderate or high nutrition risk were female gender, being Māori and other ethnicities versus European, not being married, taking multiple medications, having more depressive symptoms, cardiovascular disease and diabetes. Protective factors independently related to low nutrition risk were living with others, higher physical and social health related QOL and higher functional status. WHOQOL environmental and psychological factors were not associated with nutrition risk when other predictive factors were taken into account. CONCLUSION Nearly two thirds of participants were identified to be at higher nutrition risk. Women, living alone, taking multiple medications, with depressive symptoms, cardiovascular disease and ndiabetes were factors associated with higher nutrition risk. Those at low nutrition risk had a better functional status and physical and social health related QOL.
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Affiliation(s)
- C A Wham
- C.A. Wham, Massey University, Institute of Food Nutrition and Human Health, Auckland, New Zealand,
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15
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Wright DH, Abran D, Bhattacharya M, Hou X, Bernier SG, Bouayad A, Fouron JC, Vazquez-Tello A, Beauchamp MH, Clyman RI, Peri K, Varma DR, Chemtob S. Prostanoid receptors: ontogeny and implications in vascular physiology. Am J Physiol Regul Integr Comp Physiol 2001; 281:R1343-60. [PMID: 11641101 DOI: 10.1152/ajpregu.2001.281.5.r1343] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [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: 11/22/2022]
Abstract
Prostanoids exert significant effects on circulatory beds. They play a role in the response of the vasculature to adjustments in perfusion pressure and oxygen and carbon dioxide tension, and they mediate the actions of numerous factors. The role of prostanoids in governing circulation of the perinate is suggested to surpass that in the adult. Prostanoids are abundantly generated in the perinate. They have been implicated in autoregulation of blood flow as studied in brain and eyes. Prostaglandins are also dominant regulators of ductus arteriosus tone. The effects of these autacoids are mediated through specific G protein-coupled receptors. In addition to the pharmacological characterization of the prostanoid receptors, important advances in understanding the biology of these receptors have been made in the last decade. Their cloning and the development of animals with disrupted genes of these receptors have been very informative. The involvement of prostanoid receptors in the developing subject, especially on brain and ocular vasculature and on ductus arteriosus, has also begun to be investigated; the expression of these receptors changes with development. Some but not all of the ontogenic changes in these receptors are attributed to homologous regulation. Interestingly, in the process of elucidating their effects, functional perinuclear prostaglandin E2 receptors have been uncovered. This article reviews prostanoid receptors and addresses implications on the developing subject with attention to vascular physiology.
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Affiliation(s)
- D H Wright
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec H3G-1Y6, Canada
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16
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Najarian T, Marrache AM, Dumont I, Hardy P, Beauchamp MH, Hou X, Peri K, Gobeil F, Varma DR, Chemtob S. Prolonged hypercapnia-evoked cerebral hyperemia via K(+) channel- and prostaglandin E(2)-dependent endothelial nitric oxide synthase induction. Circ Res 2000; 87:1149-56. [PMID: 11110772 DOI: 10.1161/01.res.87.12.1149] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [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: 11/16/2022]
Abstract
Mechanisms for secondary sustained increase in cerebral blood flow (CBF) during prolonged hypercapnia are unknown. We show that induction of endothelial NO synthase (eNOS) by an increase in prostaglandins (PGs) contributes to the secondary CBF increase during hypercapnic acidosis. Ventilation of pigs with 6% CO(2) (PaCO(2 approximately)65 mm Hg; pH approximately 7.2) caused a approximately 2.5-fold increase in CBF at 30 minutes, which declined to basal values at 3 hours and gradually rose again at 6 and 8 hours; the latter increase was associated with PG elevation, nitrite formation, eNOS mRNA expression, and in situ NO synthase (NOS) reactivity (NADPH-diaphorase staining). Subjecting free-floating brain sections to acidotic conditions increased eNOS expression, the time course of which was similar to that of CBF increase. Treatment of pigs with the cyclooxygenase inhibitor diclofenac or the NOS inhibitor Nomega-nitro-L-arginine blunted the initial rise and prevented the secondary CBF increase during hypercapnic acidosis; neuronal NOS blockers 1-(2-trifluoromethylphenyl) imidazole and 3-bromo-7-nitroindazole were ineffective. Diclofenac abolished the hypercapnia-induced rise in cerebrovascular nitrite production, eNOS mRNA expression, and NADPH-diaphorase reactivity. Acidosis (pH approximately 7.15, PCO(2 approximately )40 mm Hg; 6 hours) produced similar increases in prostaglandin E(2) (PGE(2)) and eNOS mRNA levels in isolated brain microvessels and in NADPH-diaphorase reactivity of brain microvasculature; these changes were prevented by diclofenac, by the receptor-operated Ca(2+) channel blocker SK&F96365, and by the K(ATP) channel blocker glybenclamide. Acidosis increased Ca(2+) transients in brain endothelial cells, which were blocked by glybenclamide and SK&F96365 but not by diclofenac. Increased PG-related eNOS mRNA and NO-dependent vasorelaxation to substance P was detected as well in rat brain exposed to 6 hours of hypercapnia. PGE(2) was the only major prostanoid that modulated brain eNOS expression during acidosis. Thus, in prolonged hypercapnic acidosis, the secondary CBF rise is closely associated with induction of eNOS expression; this seems to be mediated by PGE(2) generated by a K(ATP) and Ca(2+) channel-dependent process.
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Affiliation(s)
- T Najarian
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
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17
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Hou X, Gobeil F, Peri K, Speranza G, Marrache AM, Lachapelle P, Roberts J, Varma DR, Chemtob S, Ellis EF. Augmented vasoconstriction and thromboxane formation by 15-F(2t)-isoprostane (8-iso-prostaglandin F(2alpha)) in immature pig periventricular brain microvessels. Stroke 2000; 31:516-24; discussion 525. [PMID: 10657431 DOI: 10.1161/01.str.31.2.516] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [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: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Oxidant stress, especially in the premature, plays a major role in the pathogenesis of hypoxic-ischemic encephalopathies mostly manifested in the periventricular region. We studied the vasomotor mode of actions of the peroxidation product 15-F(2t)-isoprostane (15-F(2t)-IsoP) (8-iso-prostaglandin F(2alpha)) on periventricular region during development. METHODS Effects of 15-F(2t)-IsoP on periventricular microvessels of fetal, newborn, and juvenile pigs were studied by video imaging and digital analysis techniques. Thromboxane formation and intracellular Ca(2+) were measured by radioimmunoassay and by using the fluorescent indicator fura 2-AM. RESULTS 15-F(2t)-IsoP-mediated constriction of periventricular microvessels decreased as a function of age such that in the fetus it was approximately 2.5-fold greater than in juvenile pigs. 15-F(2t)-IsoP evoked more thromboxane formation in the fetus than in the newborn, which was greater than that in the juvenile periventricular region; this was associated with immunoreactive thromboxane A(2) (TXA(2)) synthase expression in the fetus that was greater than that in newborn pigs, which was greater than that in juvenile pigs. 15-F(2t)-IsoP-induced vasoconstriction was markedly inhibited by TXA(2) synthase and receptor blockers (CGS12970 and L670596). Vasoconstrictor effects of the TXA(2) mimetic U46619 on fetal, neonatal, and juvenile periventricular microvessels did not differ. 15-F(2t)-IsoP increased TXA(2) synthesis by activating Ca(2+) influx through non-voltage-gated channels in endothelial cells (SK&F96365 sensitive) and N-type voltage-gated channels (omega-conotoxin sensitive) in astrocytes; smooth muscle cells were not responsive to 15-F(2t)-IsoP but generated Ca(2+) transients to U46619 via L-type voltage-sensitive channels. CONCLUSIONS 15-F(2t)-IsoP causes periventricular brain region vasoconstriction in the fetus that is greater than that in the newborn, which in turn is greater than that in the juvenile due to greater TXA(2) formation generated through distinct stimulatory pathways, including from endothelial and astroglial cells. The resulting hemodynamic compromise may contribute to the increased vulnerability of the periventricular brain areas to oxidant stress-induced injury in immature subjects.
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Affiliation(s)
- X Hou
- Centre de Recherche de l'Hôpital Sainte-Justine, Department of Pediatrics and Pharmacology, Université de Montréal, Montréal, Québec, Canada
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18
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Bhattacharya M, Peri K, Ribeiro-da-Silva A, Almazan G, Shichi H, Hou X, Varma DR, Chemtob S. Localization of functional prostaglandin E2 receptors EP3 and EP4 in the nuclear envelope. J Biol Chem 1999; 274:15719-24. [PMID: 10336471 DOI: 10.1074/jbc.274.22.15719] [Citation(s) in RCA: 175] [Impact Index Per Article: 7.0] [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: 11/06/2022] Open
Abstract
The effects of prostaglandin E2 are thought to be mediated via G protein-coupled plasma membrane receptors, termed EP. However recent data implied that prostanoids may also act intracellularly. We investigated if the ubiquitous EP3 and the EP4 receptors are localized in nuclear membranes. Radioligand binding studies on isolated nuclear membrane fractions of neonatal porcine brain and adult rat liver revealed the presence of EP3 and EP4. A perinuclear localization of EP3alpha and EP4 receptors was visualized by indirect immunocytofluorescence and confocal microscopy in porcine cerebral microvascular endothelial cells and in transfected HEK 293 cells that stably overexpress these receptors. Immunoelectron microscopy clearly revealed EP3alpha and EP4 receptors localization in the nuclear envelope of endothelial cells; this is the first demonstration of the nuclear localization of these receptors. Data also reveal that nuclear EP receptors are functional as they affect transcription of genes such as inducible nitric-oxide synthase and intranuclear calcium transients; this appears to involve pertussis toxin-sensitive G proteins. These results define a possible molecular mechanism of action of nuclear EP3 receptors.
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Affiliation(s)
- M Bhattacharya
- Department of Pharmacology & Therapeutics, McGill University, Montreal, PQ, Canada, H3G 1Y6
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19
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Abran D, Dumont I, Hardy P, Peri K, Li DY, Molotchnikoff S, Varma DR, Chemtob S. Characterization and regulation of prostaglandin E2 receptor and receptor-coupled functions in the choroidal vasculature of the pig during development. Circ Res 1997; 80:463-72. [PMID: 9118476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Ontogenic changes in choroidal vascular prostaglandin E2 (PGE2) receptors (EP1, EP2, EP3, and EP4), changes in receptor-coupled functions, and the possible role of high perinatal prostaglandin levels in regulating expression and function of these receptors were studied. PGE2 receptors and their functions on choroidal tissues were characterized by radioligand binding; by measurements of second messengers to receptor stimulation; and by vasomotor response to EP1, EP2, EP3, and EP4 ligands on perfused choroidal vascular beds from saline- and ibuprofen-treated (40 mg/kg every 4 every 4 hours for 48 hours) newborn pigs and from adult animals. PGE2 as well as EP2- and EP4-attributed choroidal stimulation elicited greater vasorelaxation in the saline-treated newborn and was associated with higher nitrite (oxidation product of NO, N omega-nitro-L-arginine inhibitable) production than in adult tissues. In contrast, EP1 and EP3 stimulation caused significantly more constriction in the adult than in the newborn, and this was associated with increased production of inositol 1,4,5-trisphosphate (IP3) and greater reduction of cAMP synthesis in the adult. Maximum [3H]PGE2 binding was also higher (3-fold) in adult than in newborn tissues. Competition binding studies revealed that of the PGE2 receptors in the adult choroid, approximately 55% were of the EP1 subtype, 8% were EP2, 22% were EP3, and 15% were EP4. Newborn choroid contained approximately 33% each of EP1 and EP2 receptors, 20% of EP3, and 15% of EP4. Inhibition of endogenous prostaglandin synthesis for 48 hours with ibuprofen in newborns to attain levels found in the adult resulted in an upregulation of [3H]PGE2 binding, EP1- and EP3-mediated vasoconstriction, and increases and decreases in IP3 and cAMP production, respectively, in newborn tissues compared with adult tissues. On the other hand, ibuprofen treatment of newborns led to a decrease in PGE2- and EP4-mediated vasorelaxation and nitrite synthesis (associated with decreased expression of endothelial NO synthase) to levels observed in adults: EP2-elicited responses in newborns were not affected by ibuprofen. In conclusion, fewer EP1 receptors (associated with vasoconstriction), more EP2 receptors, and greater EP4-coupled NO production (coupled to vasorelaxation) seem to be responsible for the increased vasodilation to PGE2 in the newborn. The decrease in prostaglandin levels with age appears to cause, on one hand, upregulation of EP1 and EP3 receptors and receptor-coupled vasoconstriction and, on the other hand, decreased EP4-coupled NO synthesis and choroidal vasodilation. Altogether, these factors result in increased vasorelaxation to PGE2 in the newborn compared with the adult. These findings may help to explain the inability of the newborn to autoregulate choroidal blood flow.
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Affiliation(s)
- D Abran
- Centre de Recherche de l'Hôpital Sainte-Justine, Department of Pediatrics, Montréal, Canada
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20
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Abstract
Prostaglandins exert significant effects on the range of cerebral blood flow autoregulation. However, the newborn exhibits a narrow cerebral blood flow autoregulatory range compared to the adult, and this apparently contributes to the susceptibility of the newborn to major perinatal complications such as intraventricular cerebral haemorrhage. Reduced vasoconstriction in response to prostaglandins due to the fewer prostaglandin receptors, especially for PGE2 (EP) and PGF2 alpha (FP), seems to contribute in part to the narrower range of cerebral blood flow autoregulation in the newborn. Evidence suggests that high levels of prostaglandins in the perinatal period are responsible for the down-regulation of neurovascular EP and FP receptors. We review the pharmacology of prostaglandin receptors, in particular PGE2 and PGF2 alpha receptors, their ontogeny on the neural vasculature, the perinatal regulation of their expression, and how these changes relate to the control of neural blood flow autoregulation.
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Affiliation(s)
- S Chemtob
- Department of Pediatrics, Centre de Recherche de l'Hôpital Sainte-Justine, Montréal, Québec, Canada
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21
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Chemtob S, Hardy P, Abran D, Li DY, Peri K, Cuzzani O, Varma DR. Peroxide-cyclooxygenase interactions in postasphyxial changes in retinal and choroidal hemodynamics. J Appl Physiol (1985) 1995; 78:2039-46. [PMID: 7665397 DOI: 10.1152/jappl.1995.78.6.2039] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [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: 01/26/2023] Open
Abstract
To test the role of reactive oxygen species and cyclooxygenase products in the retinal hemodynamic changes induced by asphyxia, we measured retinal (RBF) and choroidal blood flows (ChBF), malondialdehyde (MDA), prostaglandin E2 (PGE2), 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha), and thromboxane B2 (TxB2) in 1- to 3-day-old pigs treated with saline, the free radical scavengers U-74389F or high-dose allopurinol, the cyclooxygenase inhibitors ibuprofen or indomethacin, or the thromboxane synthase blocker CGS-13080 before and 5 and 60 min after a 5-min period of asphyxia. In saline-treated animals, RBF and ChBF increased 5 min after asphyxia and decreased at 60 min. The increases in RBF and ChBF at 5 min postasphyxia were slightly attenuated by cyclooxygenase blockers and free radical scavengers but not by thromboxane synthase inhibition, whereas all drugs prevented the decreases at 60 min. MDA, TxB2, PGE2, and 6-keto-PGF1 alpha increased 5 min after asphyxia; at 60 min, PGE2 and 6-keto-PGF1 alpha returned to nearly preasphyxial levels, but MDA and TxB2 continued to increase. Cyclooxygenase inhibition prevented the asphyxia-induced rise in MDA, and the free radical scavengers prevented that of prostanoids. In isolated eyecup preparations, H2O2 and cumene hydroperoxide constricted retinal arteries; this effect was blocked by cyclooxygenase and thromboxane synthase inhibitors. The data suggest that during oxidative stresses reactive oxygen species are generated from the cyclooxygenase pathway and, in turn, also activate the synthesis of thromboxane; the latter mediates the oxidative stress-induced ocular vasoconstriction that might trigger the neovascularization of retinopathy of prematurity.
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Affiliation(s)
- S Chemtob
- Department of Pediatrics, University of Montreal, Québec, Canada
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