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Woodman J, Fara T, Dzieciatkowska M, Trejo M, Luong N, Hansen KC, Megee PC. Cell cycle-specific cleavage of Scc2 regulates its cohesin deposition activity. Proc Natl Acad Sci U S A 2014; 111:7060-5. [PMID: 24778232 PMCID: PMC4024903 DOI: 10.1073/pnas.1321722111] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [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: 11/18/2022] Open
Abstract
Sister chromatid cohesion (SCC), efficient DNA repair, and the regulation of some metazoan genes require the association of cohesins with chromosomes. Cohesins are deposited by a conserved heterodimeric loading complex composed of the Scc2 and Scc4 proteins in Saccharomyces cerevisiae, but how the Scc2/Scc4 deposition complex regulates the spatiotemporal association of cohesin with chromosomes is not understood. We examined Scc2 chromatin association during the cell division cycle and found that the affinity of Scc2 for chromatin increases biphasically during the cell cycle, increasing first transiently in late G1 phase and then again later in G2/M. Inactivation of Scc2 following DNA replication reduces cellular viability, suggesting that this post S-phase increase in Scc2 chromatin binding affinity is biologically relevant. Interestingly, high and low Scc2 chromatin binding levels correlate strongly with the presence of full-length or amino-terminally cleaved forms of Scc2, respectively, and the appearance of the cleaved Scc2 species is promoted in vitro either by treatment with specific cell cycle-staged cellular extracts or by dephosphorylation. Importantly, Scc2 cleavage eliminates Scc2-Scc4 physical interactions, and an scc2 truncation mutant that mimics in vivo Scc2 cleavage is defective for cohesin deposition. These observations suggest a previously unidentified mechanism for the spatiotemporal regulation of cohesin association with chromosomes through cell cycle regulation of Scc2 cohesin deposition activity by Scc2 dephosphorylation and cleavage.
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Affiliation(s)
- Julie Woodman
- Molecular Biology Program, andDepartment of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045
| | - Tyler Fara
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045
| | - Monika Dzieciatkowska
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045
| | - Michael Trejo
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045
| | - Nancy Luong
- Molecular Biology Program, andDepartment of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045
| | - Kirk C Hansen
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045
| | - Paul C Megee
- Molecular Biology Program, andDepartment of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045
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Zhou W, Bercury K, Cummiskey J, Luong N, Lebin J, Freed CR. Phenylbutyrate up-regulates the DJ-1 protein and protects neurons in cell culture and in animal models of Parkinson disease. J Biol Chem 2011; 286:14941-51. [PMID: 21372141 DOI: 10.1074/jbc.m110.211029] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Parkinson disease is caused by the death of midbrain dopamine neurons from oxidative stress, abnormal protein aggregation, and genetic predisposition. In 2003, Bonifati et al. (23) found that a single amino acid mutation in the DJ-1 protein was associated with early-onset, autosomal recessive Parkinson disease (PARK7). The mutation L166P prevents dimerization that is essential for the antioxidant and gene regulatory activity of the DJ-1 protein. Because low levels of DJ-1 cause Parkinson, we reasoned that overexpression might stop the disease. We found that overexpression of DJ-1 improved tolerance to oxidative stress by selectively up-regulating the rate-limiting step in glutathione synthesis. When we imposed a different metabolic insult, A53T mutant α-synuclein, we found that DJ-1 turned on production of the chaperone protein Hsp-70 without affecting glutathione synthesis. After screening a number of small molecules, we have found that the histone deacetylase inhibitor phenylbutyrate increases DJ-1 expression by 300% in the N27 dopamine cell line and rescues cells from oxidative stress and mutant α-synuclein toxicity. In mice, phenylbutyrate treatment leads to a 260% increase in brain DJ-1 levels and protects dopamine neurons against 1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine (MPTP) toxicity. In a transgenic mouse model of diffuse Lewy body disease, long-term administration of phenylbutyrate reduces α-synuclein aggregation in brain and prevents age-related deterioration in motor and cognitive function. We conclude that drugs that up-regulate DJ-1 gene expression may slow the progression of Parkinson disease by moderating oxidative stress and protein aggregation.
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Affiliation(s)
- Wenbo Zhou
- Division of Clinical Pharmacology and Toxicology, Department of Medicine, School of Medicine, University of Colorado Denver, Aurora, Colorado 80045, USA.
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Village J, Trask C, Luong N, Chow Y, Johnson P, Koehoorn M, Teschke K. Development and evaluation of an observational Back-Exposure Sampling Tool (Back-EST) for work-related back injury risk factors. Appl Ergon 2009; 40:538-544. [PMID: 18950744 DOI: 10.1016/j.apergo.2008.09.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2007] [Revised: 05/24/2008] [Accepted: 09/03/2008] [Indexed: 05/27/2023]
Abstract
We developed and evaluated an observational Back-Exposure Sampling Tool. A literature review suggested 53 exposure variables; these were reduced to 20 following field trials. Kappas for agreement beyond chance between six observers assessing exposures in 72 photos ranged from 0.21 to 1.0, with the highest values for posture type, trunk angle, manual materials handling, hands on item, and load weight. Intraclass correlations for agreement between pairs observing 17 workers once per minute for a full-shift were >0.74 for most postural, trunk angle, and manual materials handling variables. In validity testing, the proportions of shifts in flexion/extension and lateral bending observed for 169 full-shifts were compared to inclinometer measurements. Pearson correlations were 0.42 for 45-60 degrees flexion and 0.9 for >60 degrees flexion, but only 0.11-0.19 for lateral bending and trunk flexion less than 45 degrees . When lower flexion angles were collapsed to include trunk extension, correlations increased to >0.5.
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Affiliation(s)
- J Village
- School of Environmental Health, University of British Columbia, Faculty of Graduate Studies, 3rd Floor, Library Processing Center, 2206 East Mall, Vancouver, British Columbia, Canada V6T 1Z3.
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Trask C, Teschke K, Village J, Chow Y, Johnson P, Luong N, Koehoorn M. Measuring low back injury risk factors in challenging work environments: an evaluation of cost and feasibility. Am J Ind Med 2007; 50:687-96. [PMID: 17680639 DOI: 10.1002/ajim.20497] [Citation(s) in RCA: 49] [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: 11/07/2022]
Abstract
BACKGROUND Measuring low back injury risk factors in field research presents challenges not encountered in laboratory environments. METHODS We compared the practical application of five measurement methods (observations, interviews, electromyography (EMG), inclinometry, and vibration monitoring) for 223 worker days in 50 heavy-industry worksites in western Canada. Data collection successes, challenges, costs, and data detail were documented for each method. RESULTS Measurement success rates varied from 42.2% (seatpan accelerometer) to 99.6% (post-shift interview) of worker days assessed. Missed days for direct monitoring equipment were primarily due to explosive environments, workplace conditions likely to damage the equipment, and malfunctions. Costs per successful measurement day were lowest for interviews (approximately 23 dollars), about 10-fold higher for observations and inclinometry, and more than 20-fold higher for EMG and vibration monitoring. CONCLUSIONS Costs and successful field performance need to be weighed against the added data detail gained from monitoring equipment when making choices about exposure assessment techniques for epidemiological studies.
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Affiliation(s)
- Catherine Trask
- School of Occupational and Environmental Hygiene, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4.
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Luong N, Davies CR, Wessells RJ, Graham SM, King MT, Veech R, Bodmer R, Oldham SM. Activated FOXO-mediated insulin resistance is blocked by reduction of TOR activity. Cell Metab 2006; 4:133-42. [PMID: 16890541 DOI: 10.1016/j.cmet.2006.05.013] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2005] [Revised: 04/07/2006] [Accepted: 05/19/2006] [Indexed: 11/21/2022]
Abstract
Reducing insulin/IGF signaling allows for organismal survival during periods of inhospitable conditions by regulating the diapause state, whereby the organism stockpiles lipids, reduces fertility, increases stress resistance, and has an increased lifespan. The Target of Rapamycin (TOR) responds to changes in growth factors, amino acids, oxygen tension, and energy status; however, it is unclear how TOR contributes to physiological homeostasis and disease conditions. Here, we show that reducing the function of Drosophila TOR results in decreased lipid stores and glucose levels. Importantly, this reduction of dTOR activity blocks the insulin resistance and metabolic syndrome phenotypes associated with increased activity of the insulin responsive transcription factor, dFOXO. Reduction in dTOR function also protects against age-dependent decline in heart function and increases longevity. Thus, the regulation of dTOR activity may be an ancient "systems biological" means of regulating metabolism and senescence, that has important evolutionary, physiological, and clinical implications.
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Affiliation(s)
- Nancy Luong
- The Burnham Institute for Medical Research, Cancer Research Center, Neuroscience and Aging Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USA
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Wiebe CB, Penagos H, Luong N, Slots J, Epstein E, Siegel D, Häkkinen L, Putnins EE, Larjava HS. Clinical and microbiologic study of periodontitis associated with Kindler syndrome. J Periodontol 2003; 74:25-31. [PMID: 12593592 DOI: 10.1902/jop.2003.74.1.25] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [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: 11/13/2022]
Abstract
BACKGROUND Little is known about the onset and prevalence of periodontal disease in patients with the rare Kindler syndrome, a genodermatological disorder. This study investigated the level of clinical periodontal attachment in relation to age and presence of putative periodontopathogenic bacteria in individuals with Kindler syndrome. METHODS Eighteen individuals diagnosed with Kindler syndrome and 13 control subjects, aged 4 to 37 years, from rural Panama received a limited clinical periodontal examination. Subgingival samples were collected for identification of putative periodontal pathogens by polymerase chain reaction. RESULTS Mild to severe gingivitis was a common finding in all adults of the study population. Seventy-two percent (13/18) of the Kindler patients and 46% (6/13) of the control subjects showed mild to severe periodontal disease (P = 0.001, chi-square test). The onset of periodontitis was earlier and the progression occurred at a faster rate in the Kindler group. There was a strong correlation (r = 0.83) between the level of attachment loss and age in the Kindler group and a weaker correlation (r = 0.66) in the control group. The appearance of gingival tissues suggested atypical periodontitis with spontaneous bleeding and fragile, often desquamative, gingiva. In periodontitis patients, Porphyromonas gingivallis and Diallster pneumosintes tended to occur more frequently in control individuals compared to those with Kindler syndrome. CONCLUSIONS In the Kindler group, periodontitis had an onset in early teenage years and progressed more rapidly compared to non-Kindler individuals of the same geographic and ethnic group. Clinical and microbiological findings suggest atypical periodontitis in Kindler patients. We propose to include Kindler syndrome in the category of medical disorders predisposing to destructive periodontal disease.
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Affiliation(s)
- Colin B Wiebe
- Department of Oral Biological & Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, BC.
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Luong N, Tsai J, Chen C. Susceptibilities of Eikenella corrodens, Prevotella intermedia, and Prevotella nigrescens clinical isolates to amoxicillin and tetracycline. Antimicrob Agents Chemother 2001; 45:3253-5. [PMID: 11600394 PMCID: PMC90820 DOI: 10.1128/aac.45.11.3253-3255.2001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The AB Biodisk Etest showed that 106 (100%) and 98 (92%) isolates of Eikenella corrodens were susceptible to amoxicillin and tetracycline, respectively. Twenty-three (68%) Prevotella intermedia isolates and 14 (67%) Prevotella nigrescens isolates were susceptible to amoxicillin. Seventy-nine percent of the P. intermedia isolates and 67% of the P. nigrescens isolates were susceptible to tetracycline. A higher percentage of beta-lactamase-producing isolates of P. intermedia and P. nigrescens were identified with selective agar containing amoxicillin than with nonselective agar.
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Affiliation(s)
- N Luong
- Division of Primary Oral Health Care, School of Dentistry, University of Southern California, Los Angeles, California 90089, USA
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Reach I, Luong N, Chastang C, Chakroun M, Mirshahi S, Mirshahi MC, Soria J, Desmichels D, Baumelou A. Dose effect relationship of reviparin in chronic hemodialysis: a crossover study versus nadroparin. Artif Organs 2001; 25:591-5. [PMID: 11493282 DOI: 10.1046/j.1525-1594.2001.025007591.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Low molecular weight heparins (LMWHs) are used for prevention of clotting in the dialysis circuit. The aim of this trial was to define the optimal dose of a new LMWH and to test the efficiency of a single dose at the start of the session. Fifteen patients were treated according to a double blind and crossover design during 4 blocks of 5 consecutive reviparin doses assigned randomly as 50, 60, 70, 85, and 100 IU anti-Xa/kg. Assessment was carried out on screening of fibrin rings or clots in the arterial and venous air traps and on visual detection of fiber in the dialyzer after rinsing. These clinical results were compared to plasmatic anti-Xa activity and thrombin-antithrombin (TAT) complex generation. A standard dose of 70 IU anti-Xa/kg of nadroparin was used as the control. After a bolus of 50 to 100 IU anti-Xa/kg, the occurrence of fibrin rings and clots in the air traps was dependent on three factors: dose of LMWH, time of the session, and patient status. A bolus of 85 IU anti-Xa/kg of reviparin was effective and safe for sessions of 4 h. For this dose, plasmatic anti-Xa activity was 0.96 +/- 0.28 IU/ml at Hour 2 and 0.82 +/- 0.22 IU/ml at Hour 4. TAT complexes are good markers of the activation of the coagulation. They did not increase during a 4 h session after a reviparin bolus of 100 IU/kg. For the same LMWH dose, the trial shows a great variability of the clinical effect and anti-Xa activities from one patient to another. A single dose of 85 IU anti-Xa/kg of reviparin can be used at the start of the dialysis session as a loading dose. We advise adapting the dose during the subsequent sessions according to the appearance of the blood circuit. The benefit of monitoring anti-Xa activity and TAT complexes could be tested in a further trial.
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Affiliation(s)
- I Reach
- Department of Hemodialysis, Medical and Surgical Center, La Porte de Choisy, Paris, France
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Hornych A, Rémy P, Luong N, Aumont J, Bariéty J. Biocompatibility of haemodialysis membranes: haemodialysis-related leukotriene B4 and C4 generation. France. Nephron Clin Pract 1996; 74:11-8. [PMID: 8883014 DOI: 10.1159/000189275] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [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: 02/02/2023] Open
Abstract
UNLABELLED The aim of our study was (1) to verify whether haemodialysis (HD) with cuprophane (CUP) and polyacrylonitrile (PAN) membranes is associated with the release of vasoactive leukotriene (LT) C4 and chemotactic LTB4 and (2) to analyse the respective roles of lipoxygenase and cyclo-oxygenase metabolites of arachidonic acid in membrane bio-incompatibility. The investigation was performed in 10 uremic patients using hollow-fibre dialysers and dialysed successively, in random order, with CUP and PAN membranes. The arterial and venous (from dialyser) blood was sampled for the measurement of biochemical parameters, plasma LTC4, LTB4 and prostaglandins (PG) 6-keto-F1 alpha, E2, F2 alpha and thromboxane B2 before and after 15, 30 and 240 min of HD. Eicosanoids were measured by RIA after prior extraction and HPLC separation. RESULTS CUP HD was associated with a marked early leukopenia and a delayed decrease in blood pO2. Simultaneously, plasma LTB4 and LTC4 increased significantly in arterial blood after 30 min of HD and in venous blood at the end of session of 240 min. Cyclo-oxygenase metabolites increased as well, but nonsignificantly, with a maximum at the end of HD. PAN HD did not significantly change white blood cell count, pO2, or plasma eicosanoid levels. CONCLUSION CUP membranes stimulate the release of proinflammatory and vasoactive LTB4 and LTC4. PAN membrane haemodialysis is without such side effects. The release of LTs may be an additional valuable marker of membrane bioincompatibility.
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Affiliation(s)
- A Hornych
- Department of Nephrology, U-430 INSERM, Broussais Hospital, Paris
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Paul JL, Roch-Arveiller M, Man NK, Luong N, Moatti N, Raichvarg D. Influence of uremia on polymorphonuclear leukocytes oxidative metabolism in end-stage renal disease and dialyzed patients. Nephron Clin Pract 1991; 57:428-32. [PMID: 1646409 DOI: 10.1159/000186308] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The oxygen (O2) consumption, and superoxide anion (O2-.) and hydrogen peroxide (H2O2) production by polymorphonuclear leukocytes (PMNs) were investigated in 5 end-stage renal disease patients, before and after the 1st, 4th and 10th dialysis sessions. Resting values of O2-. production and O2 consumption were not significantly different from values for PMNs from normal subjects. After stimulation by opsonized zymosan or phorbol myristate acetate, the three parameters measured were significantly (p less than 0.001) enhanced in comparison with healthy control values. Cross-incubation studies showed a lack of effect of patient plasma on O2-. production by stimulated control cells: PMN oxidative metabolism would therefore appear to be increased in these patients. The anomalies observed probably arise via a mechanism involving a cellular dysfunction resulting from the renal disease, rather than from the presence of a plasma factor.
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Affiliation(s)
- J L Paul
- Laboratoire de Biochimie, Hôpital Broussais, Paris, France
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