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Pomerleau J, Weidmann C, Coutant K, Lowry CM, Veilleux MP, Bérubé J, Wagner JR, Landreville S. Experimental eye research / short communication format characterization of DNA hydroxymethylation in the ocular choroid. Exp Eye Res 2021; 205:108473. [PMID: 33524365 DOI: 10.1016/j.exer.2021.108473] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 01/05/2021] [Accepted: 01/21/2021] [Indexed: 12/11/2022]
Abstract
DNA methylation and hydroxymethylation represent important epigenetic modifications involved in cell differentiation. DNA hydroxymethylation can be used to classify independent biological samples by tissue type. Relatively little is known regarding the genomic abundance and function of 5-hydroxymethylcytosine (5-hmC) in ocular tissues. The choroid supplies oxygen and nutrients to the outer retina through its dense network of blood vessels. This connective tissue is mainly composed of pigmented melanocytes, and stromal fibroblasts. Since DNA hydroxymethylation level is relatively high in cutaneous melanocytes, we investigated the presence of 5-hmC in choroidal melanocytes, as well as the expression of ten-eleven translocation methylcytosine dioxygenases (TETs) and isocitrate dehydrogenases (IDHs) implicated in this DNA demethylation pathway. Immunofluorescence, DNA slot blots and liquid chromatography coupled to tandem mass spectrometry performed with choroidal tissues and melanocytes within these tissues revealed that they have a relatively high level of 5-hmC. We also examined the expression of TET1/2 and IDH1/2 in choroidal melanocytes by gene expression profiling, qPCR and Western blotting. In addition, we detected decreased levels of 5-hmC when choroidal melanocytes were exposed to a lower concentration of oxygen. Our study therefore demonstrates that DNA hydroxymethylation is present in choroidal melanocytes, and that the abundance of this epigenetic mark is impacted by hypoxia.
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Affiliation(s)
- Jade Pomerleau
- Axe Médecine Régénératrice and Centre Universitaire d'Ophtalmologie (CUO)-Recherche, Centre de Recherche du CHU de Québec-Université Laval, Quebec City, QC, Canada; Département d'Ophtalmologie et ORL-CCF, Faculté de Médecine, Université Laval, Quebec City, QC, Canada; Centre de Recherche en Organogénése Expérimentale de l'Université Laval/LOEX, Quebec City, QC, Canada
| | - Cindy Weidmann
- Axe Médecine Régénératrice and Centre Universitaire d'Ophtalmologie (CUO)-Recherche, Centre de Recherche du CHU de Québec-Université Laval, Quebec City, QC, Canada; Département d'Ophtalmologie et ORL-CCF, Faculté de Médecine, Université Laval, Quebec City, QC, Canada; Centre de Recherche en Organogénése Expérimentale de l'Université Laval/LOEX, Quebec City, QC, Canada; Centre de Recherche sur le Cancer de l'Université Laval, Quebec City, QC, Canada
| | - Kelly Coutant
- Axe Médecine Régénératrice and Centre Universitaire d'Ophtalmologie (CUO)-Recherche, Centre de Recherche du CHU de Québec-Université Laval, Quebec City, QC, Canada; Département d'Ophtalmologie et ORL-CCF, Faculté de Médecine, Université Laval, Quebec City, QC, Canada; Centre de Recherche en Organogénése Expérimentale de l'Université Laval/LOEX, Quebec City, QC, Canada; Centre de Recherche sur le Cancer de l'Université Laval, Quebec City, QC, Canada
| | - Carolyne-Mary Lowry
- Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Marie-Pier Veilleux
- Axe Médecine Régénératrice and Centre Universitaire d'Ophtalmologie (CUO)-Recherche, Centre de Recherche du CHU de Québec-Université Laval, Quebec City, QC, Canada; Département d'Ophtalmologie et ORL-CCF, Faculté de Médecine, Université Laval, Quebec City, QC, Canada; Centre de Recherche en Organogénése Expérimentale de l'Université Laval/LOEX, Quebec City, QC, Canada; Centre de Recherche sur le Cancer de l'Université Laval, Quebec City, QC, Canada
| | - Julie Bérubé
- Axe Médecine Régénératrice and Centre Universitaire d'Ophtalmologie (CUO)-Recherche, Centre de Recherche du CHU de Québec-Université Laval, Quebec City, QC, Canada; Centre de Recherche en Organogénése Expérimentale de l'Université Laval/LOEX, Quebec City, QC, Canada; Centre de Recherche sur le Cancer de l'Université Laval, Quebec City, QC, Canada
| | - J Richard Wagner
- Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Solange Landreville
- Axe Médecine Régénératrice and Centre Universitaire d'Ophtalmologie (CUO)-Recherche, Centre de Recherche du CHU de Québec-Université Laval, Quebec City, QC, Canada; Département d'Ophtalmologie et ORL-CCF, Faculté de Médecine, Université Laval, Quebec City, QC, Canada; Centre de Recherche en Organogénése Expérimentale de l'Université Laval/LOEX, Quebec City, QC, Canada; Centre de Recherche sur le Cancer de l'Université Laval, Quebec City, QC, Canada.
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St-Pierre V, Vandenberghe C, Lowry CM, Fortier M, Castellano CA, Wagner R, Cunnane SC. Plasma Ketone and Medium Chain Fatty Acid Response in Humans Consuming Different Medium Chain Triglycerides During a Metabolic Study Day. Front Nutr 2019; 6:46. [PMID: 31058159 PMCID: PMC6481320 DOI: 10.3389/fnut.2019.00046] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [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: 11/27/2018] [Accepted: 03/27/2019] [Indexed: 12/22/2022] Open
Abstract
Background: Medium chain triglycerides (MCT) are ketogenic but the relationship between the change in plasma ketones and the change plasma medium chain fatty acids (MCFA)—octanoate, decanoate, or dodecanoate—after an oral dose of MCT is not well-known. An 8 h metabolic study day is a suitable model to assess the acute effects on plasma ketones and MCFA after a dose of tricaprylin (C8), tricaprin (C10), trilaurin (C12) or mixed MCT (C8C10). Objective: To assess in healthy humans the relationship between the change in plasma ketones, and octanoate, decanoate and dodecanoate in plasma total lipids during an 8 h metabolic study day in which a first 20 ml dose of the homogenized test oil is taken with breakfast and a second 20 ml dose is taken 4 h later without an accompanying meal. Results: The change in plasma acetoacetate, β-hydroxybutyrate and total ketones was highest after C8 (0.5 to 3 h post-dose) and was lower during tests in which octanoate was absent or was diluted by C10 in the test oil. The plasma ketone response was also about 2 fold higher without an accompanying meal (P = 0.012). However, except during the pure C10 test, the response of octanoate, decanoate or dodecanoate in plasma total lipids to the test oils was not affected by consuming an accompanying meal. Except with C12, the 4 h area-under-the-curve of plasma β-hydroxybutyrate/acetoacetate was 2–3 fold higher when no meal was consumed (P < 0.04). Conclusion: C8 was about three times more ketogenic than C10 and about six times more ketogenic than C12 under these acute metabolic test conditions, an effect related to the post-dose increase in octanoate in plasma total lipids.
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Affiliation(s)
| | | | - Carolyne-Mary Lowry
- Departments of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Sherbrooke, QC, Canada
| | | | | | - Richard Wagner
- Research Center on Aging, Sherbrooke, QC, Canada.,Departments of Nuclear Medicine and Radiobiology, Université de Sherbrooke, Sherbrooke, QC, Canada.,Departments of Medicine, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Stephen C Cunnane
- Research Center on Aging, Sherbrooke, QC, Canada.,Departments of Medicine, Université de Sherbrooke, Sherbrooke, QC, Canada.,Departments of Pharmacology and Physiology, Université de Sherbrooke, Sherbrooke, QC, Canada
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Lowry CM, Marty FM, Vargas SO, Lee JT, Fiumara K, Deykin A, Baden LR. Safety of aerosolized liposomal versus deoxycholate amphotericin B formulations for prevention of invasive fungal infections following lung transplantation: a retrospective study. Transpl Infect Dis 2007; 9:121-5. [PMID: 17461997 DOI: 10.1111/j.1399-3062.2007.00209.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Nebulized amphotericin B deoxycholate (AmBd) has been used to prevent invasive pulmonary aspergillosis after lung transplantation. METHODS In this retrospective study we compared the safety and tolerability of nebulized AmBd and nebulized liposomal amphotericin B (L-AmB) in 38 consecutive lung transplant recipients. Progress notes, medication administration records, microbiology, and pulmonary function reports were reviewed. Histologic sections from lung tissue were examined. Plasma amphotericin B levels were measured. RESULTS A total of 1206 doses of AmBd and 1149 doses of L-AmB were administered. Eighteen patients received AmBd only, 11 received L-AmB only, and 9 received the medications sequentially. The total number of complaints vs. the number of doses administered was 1.0% for AmBd-treated patients and 1.2% for L-AmB-treated patients. No differences were observed between the treatment groups on lung biopsy specimens. Plasma amphotericin B levels were <0.2-0.9 microg/mL in AmBd-treated patients and <0.2 microg/mL in L-AmB-treated patients. CONCLUSIONS In lung transplant recipients, both inhaled AmBd and L-AmB were safe and well tolerated over a large number of medication exposures.
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Affiliation(s)
- C M Lowry
- Department of Pharmacy, Brigham & Women's Hospital, Boston, MA 02115, USA
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Bigler ED, Lowry CM, Anderson CV, Johnson SC, Terry J, Steed M. Dementia, quantitative neuroimaging, and apolipoprotein E genotype. AJNR Am J Neuroradiol 2000; 21:1857-68. [PMID: 11110538 PMCID: PMC7974277] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2000] [Indexed: 02/18/2023]
Abstract
BACKGROUND AND PURPOSE Quantitative MR imaging differences in an elderly population of subjects with various clinical disorders (including dementia, particularly Alzheimer's disease and vascular dementia) and disorders of mild cognitive impairment were examined. Potential quantitative MR differences were assessed by presence or absence of the apolipoprotein E (APOE) epsilon4 allele and by level of cognitive deficit. METHODS One hundred eighty subjects with a diagnosis of dementia or other clinical disorders were identified from an eligible population of 5,677 elderly individuals. Age, duration of disease, and head size (where appropriate) were considered as covariates. APOE genotype was determined by polymerase chain reaction using buccal material. Axial and coronal intermediate- and T2-weighted MR images were quantified using a multispectral segmentation algorithm. Cognitive status was assessed by means of a modified Mini-Mental Status Examination. RESULTS All types of dementing illness showed significant volume reductions in the majority of structures examined, particularly in the total brain, hippocampus, and white and gray matter, and increased CSF and ventricular volumes. Subjects with mild cognitive impairment showed fewer atrophic changes but were still distinguishable from the 24 control subjects. Presence of an epsilon4 allele was associated with smaller hippocampal volume in subjects with Alzheimer's disease and vascular dementia within just 1 year of disease onset. For other analyses, atrophy related to the presence of the epsilon4 allele disappeared after controlling for age and length of disease. CONCLUSION The effects of the epsilon4 allele on brain morphology may be subtly expressed early in the development of dementia, but do not specifically affect cerebral atrophy thereafter. Cognitive impairment is associated with atrophy irrespective of diagnosis and presence of epsilon4.
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Affiliation(s)
- E D Bigler
- Department of Psychology and Neuroscience, Brigham Young University, Provo, UT 84602, USA
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O'Beirne C, Lowry CM, Voorheis HP. Both IgM and IgG anti-VSG antibodies initiate a cycle of aggregation-disaggregation of bloodstream forms of Trypanosoma brucei without damage to the parasite. Mol Biochem Parasitol 1998; 91:165-93. [PMID: 9574934 DOI: 10.1016/s0166-6851(97)00191-6] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.5] [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: 02/07/2023]
Abstract
Bloodstream forms of Trypanosoma brucei, when aggregated in the presence of either acute immune plasma, acute immune serum, purified IgM anti-VSG antibodies or purified IgG anti-VSG antibodies, subsequently disaggregated with a t1/2 for disaggregation of 15 min at 37 degrees C as long as the trypanosomes were metabolically active at the beginning of the experiment and maintained during the experiment in a suitable supporting medium. The t1/2 for disaggregation was found to be directly dependent upon temperature and inversely proportional to the antibody concentration. The trypanosomes were always motile and metabolically active during aggregation and after disaggregation and were fully infective for a mammalian host following disaggregation as well as able to grow and divide normally during axenic culture. The disaggregation was strictly energy dependent and was inhibited when intracellular ATP levels were reduced by salicylhydroxamic acid or following addition of oligomycin while respiring glucose. In addition the process of disaggregation was dependent upon normal endosomal activity as evidenced by its sensitivity to a wide variety of inhibitors of various endosomal functions. Disaggregation was not due to separation of immunoglobulin chains by either disulphide reduction or disulphide exchange reactions and gross proteolytic cleavage of the immunoglobulins attached to the surface of the parasite was not detected. In addition, gross cleavage or release of the VSG from the surface of the cell did not occur during disaggregation but proteolytic cleavage of a small proportion of either the VSG or the immunoglobulins could not be eliminated from consideration. Finally the mechanism of disaggregation was found to be a regulated process, independent of Ca2+ movements but dependent upon the activity of protein kinase C or related kinases and inhibited by the activity of protein kinase A as evidenced by the effects of a panel of inhibitors and cAMP analogues on the process of disaggregation. The mechanism of disaggregation displayed by trypanosomes aggregated by anti-VSG antibody is proposed to form part of the parasite's defence against the host immune system and functions to aid survival of trypanosomes in the presence of antibody in the host prior to the occurrence of a VSG switching event.
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Affiliation(s)
- C O'Beirne
- Department of Biochemistry, Trinity College, Dublin, Ireland
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