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Schreier HK, Wiehe RS, Ricchetti M, Wiesmüller L. Polymerase ζ is Involved in Mitochondrial DNA Maintenance Processes in Concert with APE1 Activity. Genes (Basel) 2022; 13:genes13050879. [PMID: 35627264 PMCID: PMC9141751 DOI: 10.3390/genes13050879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 05/10/2022] [Accepted: 05/11/2022] [Indexed: 01/25/2023] Open
Abstract
Mitochondrial DNA (mtDNA) damaged by reactive oxygen species (ROS) triggers so far poorly understood processes of mtDNA maintenance that are coordinated by a complex interplay among DNA repair, DNA degradation, and DNA replication. This study was designed to identify the proteins involved in mtDNA maintenance by applying a special long-range PCR, reflecting mtDNA integrity in the minor arc. A siRNA screening of literature-based candidates was performed under conditions of enforced oxidative phosphorylation revealing the functional group of polymerases and therein polymerase ζ (POLZ) as top hits. Thus, POLZ knockdown caused mtDNA accumulation, which required the activity of the base excision repair (BER) nuclease APE1, and was followed by compensatory mtDNA replication determined by the single-cell mitochondrial in situ hybridization protocol (mTRIP). Quenching reactive oxygen species (ROS) in mitochondria unveiled an additional, ROS-independent involvement of POLZ in the formation of a typical deletion in the minor arc region. Together with data demonstrating the localization of POLZ in mitochondria, we suggest that POLZ plays a significant role in mtDNA turnover, particularly under conditions of oxidative stress.
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Affiliation(s)
- Heike Katrin Schreier
- Department of Obstetrics and Gynecology, Ulm University, 89075 Ulm, Germany; (H.K.S.); (R.S.W.)
| | - Rahel Stefanie Wiehe
- Department of Obstetrics and Gynecology, Ulm University, 89075 Ulm, Germany; (H.K.S.); (R.S.W.)
| | - Miria Ricchetti
- Department of Developmental and Stem Cell Biology, Institute Pasteur, CEDEX 15, 75724 Paris, France;
| | - Lisa Wiesmüller
- Department of Obstetrics and Gynecology, Ulm University, 89075 Ulm, Germany; (H.K.S.); (R.S.W.)
- Correspondence:
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2
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Sullivan ED, Longley MJ, Copeland WC. Polymerase γ efficiently replicates through many natural template barriers but stalls at the HSP1 quadruplex. J Biol Chem 2021; 295:17802-17815. [PMID: 33454015 DOI: 10.1074/jbc.ra120.015390] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 10/05/2020] [Indexed: 12/27/2022] Open
Abstract
Faithful replication of the mitochondrial genome is carried out by a set of key nuclear-encoded proteins. DNA polymerase γ is a core component of the mtDNA replisome and the only replicative DNA polymerase localized to mitochondria. The asynchronous mechanism of mtDNA replication predicts that the replication machinery encounters dsDNA and unique physical barriers such as structured genes, G-quadruplexes, and other obstacles. In vitro experiments here provide evidence that the polymerase γ heterotrimer is well-adapted to efficiently synthesize DNA, despite the presence of many naturally occurring roadblocks. However, we identified a specific G-quadruplex-forming sequence at the heavy-strand promoter (HSP1) that has the potential to cause significant stalling of mtDNA replication. Furthermore, this structured region of DNA corresponds to the break site for a large (3,895 bp) deletion observed in mitochondrial disease patients. The presence of this deletion in humans correlates with UV exposure, and we have found that efficiency of polymerase γ DNA synthesis is reduced after this quadruplex is exposed to UV in vitro.
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Affiliation(s)
- Eric D Sullivan
- Mitochondrial DNA Replication Group, Genome Integrity and Structural Biology Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Matthew J Longley
- Mitochondrial DNA Replication Group, Genome Integrity and Structural Biology Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - William C Copeland
- Mitochondrial DNA Replication Group, Genome Integrity and Structural Biology Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina, USA.
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3
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Gary AS, Dorr MM, Rochette PJ. The T414G mitochondrial DNA mutation: a biomarker of ageing in human eye. Mutagenesis 2021; 36:187-192. [PMID: 33453104 DOI: 10.1093/mutage/geab003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 01/13/2021] [Indexed: 11/14/2022] Open
Abstract
The mitochondrial mutation T414G (mtDNAT414G) has been shown to accumulate in aged and sun-exposed skin. The human eye is also exposed to solar harmful rays. More precisely, the anterior structures of the eye (cornea, iris) filter UV rays and the posterior portion of the eye (retina) is exposed to visible light. These rays can catalyse mutations in mitochondrial DNA such as the mtDNAT414G, but the latter has never been investigated in the human ocular structures. In this study, we have developed a technique to precisely assess the occurrence of mtDNAT414G. Using this technique, we have quantified mtDNAT414G in different human ocular structures. We found an age-dependent accumulation of mtDNAT414G in the corneal stroma, the cellular layer conferring transparency and rigidity to the human cornea, and in the iris. Since cornea and iris are two anterior ocular structures exposed to solar UV rays, this suggests that the mtDNAT414G mutation is resulting from cumulative solar exposure and this could make the mtDNAT414G a good marker of solar exposure. We have previously shown that the mtDNACD4977 and mtDNA3895 deletions accumulate over time in photo-exposed ocular structures. With the addition of mtDNAT414G mutation, it becomes feasible to combine the levels of these different mtDNA mutations to obtain an accurate assessment of the solar exposure that an individual has accumulated during his/her lifetime.
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Affiliation(s)
- Anne-Sophie Gary
- Centre de recherche du CHU de Québec - Université Laval, Axe Médecine Régénératrice, Hôpital du Saint-Sacrment, Québec, Qc, Canada.,Centre de recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Québec, Qc, Canada
| | - Marie M Dorr
- Centre de recherche du CHU de Québec - Université Laval, Axe Médecine Régénératrice, Hôpital du Saint-Sacrment, Québec, Qc, Canada.,Centre de recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Québec, Qc, Canada
| | - Patrick J Rochette
- Centre de recherche du CHU de Québec - Université Laval, Axe Médecine Régénératrice, Hôpital du Saint-Sacrment, Québec, Qc, Canada.,Centre de recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Québec, Qc, Canada.,Département d'Ophtalmologie et ORL-Chirurgie Cervico-Faciale, Université Laval, Québec, Qc, Canada
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4
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Kozak I, Oystreck DT, Abu-Amero KK, Nowilaty SR, Alkhalidi H, Elkhamary SM, Mohamed S, Hamad MHA, Salih MA, Blakely EL, Taylor RW, Bosley TM. NEW OBSERVATIONS REGARDING THE RETINOPATHY OF GENETICALLY CONFIRMED KEARNS-SAYRE SYNDROME. Retin Cases Brief Rep 2018; 12:349-358. [PMID: 28296806 DOI: 10.1097/icb.0000000000000503] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
PURPOSE To report novel retinal findings in Kearns-Sayre syndrome and correlate degree of retinopathy with other clinical findings. METHODS Observational case series of patients from Saudi Arabia with retinal and neuroophthalmologic examinations, medical chart review, and mitochondrial genetic evaluation. RESULTS The three unrelated patients had progressive external ophthalmoplegia and pigmentary retinopathy bilaterally. Muscle biopsy in two of the cases revealed mitochondrial myopathy. All three had abnormal findings on neuroimaging and modestly reduced visual acuity in both eyes with a variable pigmentary retinopathy. One of the patients had bilateral subretinal fibrosis with a full-thickness macular hole in the right eye. All three patients had single, large-scale mitochondrial DNA (mtDNA) deletions (5.0-7.6 kb in size) with blood mtDNA heteroplasmy levels ranging from below 20% to 57%. Severity of pigmentary retinopathy did not correlate with severity of progressive external ophthalmoplegia, but did correspond grossly with electroretinographic abnormalities, just as the degree of ocular motility restriction and ptosis in each patient correlated with the size of their extraocular muscles on neuroimaging. In addition, the size of the single, large-scale mtDNA deletion and level of mtDNA heteroplasmy corresponded with degree of ocular motility restriction but not with severity of retinopathy. CONCLUSION Subretinal fibrosis and macular hole are novel retinal observations which expand clinical profile in Kearns-Sayre syndrome. Genetic testing for mtDNA deletions and heteroplasmy in blood, muscle biopsy, careful ocular and retinal examination including electroretinography, and imaging are indispensable tests for this condition.
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Affiliation(s)
- Igor Kozak
- King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | - Darren T Oystreck
- Department of Ophthalmology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
- The Division of Ophthalmology, Faculty of Health Sciences, University of Stellenbosch, Tygerberg, South Africa
| | - Khaled K Abu-Amero
- Department of Ophthalmology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
- Department of Ophthalmology, College of Medicine, University of Florida, Jacksonville, Florida
| | | | | | | | - Sarar Mohamed
- Pediatrics, College of Medicine, King Saud University Riyadh, Saudi Arabia
| | | | - Mustafa A Salih
- Pediatrics, College of Medicine, King Saud University Riyadh, Saudi Arabia
| | - Emma L Blakely
- The Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Robert W Taylor
- The Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Thomas M Bosley
- Department of Ophthalmology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
- The Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland
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5
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Kamenisch Y, Ivanova I, Drexler K, Berneburg M. UVA, metabolism and melanoma: UVA makes melanoma hungry for metastasis. Exp Dermatol 2018; 27:941-949. [PMID: 29658146 DOI: 10.1111/exd.13561] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/05/2018] [Indexed: 12/13/2022]
Abstract
Ultraviolet (UV) radiation has a plethora of effects on human tissues. In the UV spectrum, wavelengths above 320 nm fall into the UVA range, and for these, it has been shown that they induce reactive oxygen species (ROS), DNA mutations and are capable to induce melanoma in mice. In addition to this, it was recently shown that UVA irradiation and UVA-induced ROS also increase glucose metabolism of melanoma cells. UVA irradiation causes a persistent increase in glucose consumption, accompanied by increased glycolysis, increased lactic acid production and activation of the pentose phosphate pathway. Furthermore, it was shown that the enhanced secretion of lactic acid is important for invasion of melanoma in vitro. The current knowledge of this link between UVA, metabolism and melanoma, possible mechanisms of UVA-induced glucose metabolism and their starting points are discussed in this review with focus on ROS- and UVA-induced cellular stress signalling, DNA damage signalling and DNA repair systems. When looking at the benefits of UVA-induced glucose metabolism, it becomes apparent that there are more advantages of these metabolic changes than one would expect. Besides the role of lactic acid as initiator of protease expression and invasion, its role for immune escape of melanoma cells and the pentose phosphate pathway-derived nicotinamide adenine dinucleotide phosphate (NADPH) as part of a ROS detoxification strategy are discussed.
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Affiliation(s)
- York Kamenisch
- Department of Dermatology, University Hospital Regensburg, Regensburg, Germany
| | - Irina Ivanova
- Department of Dermatology, University Hospital Regensburg, Regensburg, Germany
| | - Konstantin Drexler
- Department of Dermatology, University Hospital Regensburg, Regensburg, Germany
| | - Mark Berneburg
- Department of Dermatology, University Hospital Regensburg, Regensburg, Germany
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6
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Optogenetik als mögliche Therapie bei degenerativen Netzhauterkrankungen. MED GENET-BERLIN 2017. [DOI: 10.1007/s11825-017-0135-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Zusammenfassung
Bei neurodegenerativen Erkrankungen der Netzhaut sind die lichtempfindlichen Zellen, die Photorezeptoren, oft als Erstes betroffen. Die Optogenetik ist ein vielversprechender Ansatz, die Netzhaut wieder lichtempfindlich zu machen und dadurch das Sehvermögen wiederherzustellen. Bei der Optogenetik werden lichtempfindliche Proteine über gentechnische Methoden in die Netzhaut eingebracht; die Aktivität der Zielzellen wird durch diese Behandlung durch Licht beeinflussbar. Dieser Einfluss kann die direkte lichtinduzierte Änderung des Membranpotenzials sein (sowohl hemmend als auch erregend) oder die lichtinduzierte Aktivierung intrazellulärer Signalkaskaden. Dies hat zur Folge, dass das Zielgewebe, die Netzhaut, wieder auf Licht reagiert. Diese Übersicht beschreibt die Prinzipien der Optogenetik und den gegenwärtigen Stand im Hinblick auf ihre Anwendung zur Behandlung von Blindheit.
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7
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Zinflou C, Rochette PJ. Ultraviolet A-induced oxidation in cornea: Characterization of the early oxidation-related events. Free Radic Biol Med 2017; 108:118-128. [PMID: 28342848 DOI: 10.1016/j.freeradbiomed.2017.03.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 03/08/2017] [Accepted: 03/20/2017] [Indexed: 11/18/2022]
Abstract
Exposure to sunlight ultraviolet-A (UVA), the main component of solar UV reaching the eyes, is suspected to play an important part in the onset of ocular pathologies. UVA primary biological deleterious effects arise from the photo-induction of oxidative stress in cells. However, the molecular bases linking UVA-induced oxidation to UVA toxicity in eyes remain poorly understood, especially with regards to the cornea. To shed some light on this issue, we have investigated the susceptibility and response potential of the different corneal cellular layers (epithelium, stroma and endothelium) to UVA-induced oxidation. We have monitored UVA-induced immediate effects on cellular redox balance, on mitochondrial membrane potential, on 8-Hydroxy-2'-deoxyguanosine (8-OHdG) accumulation in cellular DNA and on S-glutathionylated proteins (PSSG) levels along whole rabbit corneas. Higher redox imbalance was observed in the posterior part of the cornea following irradiation. Conversely, UVA-altered mitochondrial membrane potentials were observed only in anterior portions of the cornea. UVA-induced 8-OHdG were found in nuclear DNA of epithelia, while they were found in both nuclear and mitochondrial DNA in stromal and endothelial cells. Finally, significantly higher levels of cytosolic PSSG were measured in epithelia and endothelia immediately after UVA exposure, but not in stromas. Taken together, our findings indicate that while corneal epithelial cells are subjected to important modifications in response to UVA exposure, they efficiently limit the early manifestations of UVA-induced toxicity. On the other hand, the corneal endothelium is more susceptible to UVA-induced oxidation-related toxicity.
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Affiliation(s)
- Corinne Zinflou
- Axe Médecine Régénératrice, Centre de Recherche du CHU de Québec - Université Laval, Hôpital du Saint-Sacrement, Québec, QC, Canada; Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Université Laval, Québec, QC, Canada
| | - Patrick J Rochette
- Axe Médecine Régénératrice, Centre de Recherche du CHU de Québec - Université Laval, Hôpital du Saint-Sacrement, Québec, QC, Canada; Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Université Laval, Québec, QC, Canada; Département d'Ophtalmologie et ORL - chirurgie cervico-faciale, Université Laval, Québec, QC, Canada.
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8
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Decreased Integrity, Content, and Increased Transcript Level of Mitochondrial DNA Are Associated with Keratoconus. PLoS One 2016; 11:e0165580. [PMID: 27783701 PMCID: PMC5081165 DOI: 10.1371/journal.pone.0165580] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 10/16/2016] [Indexed: 01/01/2023] Open
Abstract
Oxidative stress may play an important role in the pathogenesis of keratoconus (KC). Mitochondrial DNA (mtDNA) is involved in mitochondrial function, and the mtDNA content, integrity, and transcript level may affect the generation of reactive oxygen species (ROS) and be involved in the pathogenesis of KC. We designed a case-control study to research the relationship between KC and mtDNA integrity, content and transcription. One-hundred ninety-eight KC corneas and 106 normal corneas from Chinese patients were studied. Quantitative real-time PCR was used to measure the relative mtDNA content, transcript levels of mtDNA and related genes. Long-extension PCR was used to detect mtDNA damage. ROS, mitochondrial membrane potential and ATP were measured by respective assay kit, and Mito-Tracker Green was used to label the mitochondria. The relative mtDNA content of KC corneas was significantly lower than that of normal corneas (P = 9.19×10−24), possibly due to decreased expression of the mitochondrial transcription factor A (TFAM) gene (P = 3.26×10−3). In contrast, the transcript levels of mtDNA genes were significantly increased in KC corneas compared with normal corneas (NADH dehydrogenase subunit 1 [ND1]: P = 1.79×10−3; cytochrome c oxidase subunit 1 [COX1]: P = 1.54×10−3; NADH dehydrogenase subunit 1, [ND6]: P = 4.62×10−3). The latter may be the result of increased expression levels of mtDNA transcription-related genes mitochondrial RNA polymerase (POLRMT) (P = 2.55×10−4) and transcription factor B2 mitochondrial (TFB2M) (P = 7.88×10−5). KC corneas also had increased mtDNA damage (P = 3.63×10−10), higher ROS levels, and lower mitochondrial membrane potential and ATP levels compared with normal corneas. Decreased integrity, content and increased transcript level of mtDNA are associated with KC. These changes may affect the generation of ROS and play a role in the pathogenesis of KC.
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9
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Finsterer J, Zarrouk-Mahjoub S, Daruich A. The Eye on Mitochondrial Disorders. J Child Neurol 2016; 31:652-62. [PMID: 26275973 DOI: 10.1177/0883073815599263] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Accepted: 07/08/2015] [Indexed: 11/16/2022]
Abstract
Ophthalmologic manifestations of mitochondrial disorders are frequently neglected or overlooked because they are often not regarded as part of the phenotype. This review aims at summarizing and discussing the etiology, pathogenesis, diagnosis, and treatment of ophthalmologic manifestations of mitochondrial disorders. Review of publications about ophthalmologic involvement in mitochondrial disorders by search of Medline applying appropriate search terms. The eye is frequently affected by syndromic as well as nonsyndromic mitochondrial disorders. Primary and secondary ophthalmologic manifestations can be differentiated. The most frequent ophthalmologic manifestations of mitochondrial disorders include ptosis, progressive external ophthalmoplegia, optic atrophy, retinopathy, and cataract. More rarely occurring are nystagmus and abnormalities of the cornea, ciliary body, intraocular pressure, the choroidea, or the brain secondarily affecting the eyes. It is important to recognize and diagnose ophthalmologic manifestations of mitochondrial disorders as early as possible because most are accessible to symptomatic treatment with partial or complete short-term or long-term beneficial effect. Ophthalmologic manifestations of mitochondrial disorders need to be appropriately diagnosed to initiate the most effective management and guarantee optimal outcome.
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Affiliation(s)
| | | | - Alejandra Daruich
- Department of Ophthalmology, University of Lausanne, Jules-Gonin Eye Hospital, Switzerland
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10
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Rifkin RF, Dayet L, Queffelec A, Summers B, Lategan M, d’Errico F. Evaluating the Photoprotective Effects of Ochre on Human Skin by In Vivo SPF Assessment: Implications for Human Evolution, Adaptation and Dispersal. PLoS One 2015; 10:e0136090. [PMID: 26353012 PMCID: PMC4564224 DOI: 10.1371/journal.pone.0136090] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 07/29/2015] [Indexed: 11/18/2022] Open
Abstract
Archaeological indicators of cognitively modern behaviour become increasingly prevalent during the African Middle Stone Age (MSA). Although the exploitation of ochre is viewed as a key feature of the emergence of modern human behaviour, the uses to which ochre and ochre-based mixtures were put remain ambiguous. Here we present the results of an experimental study exploring the efficacy of ochre as a topical photoprotective compound. This is achieved through the in vivo calculation of the sun protection factor (SPF) values of ochre samples obtained from Ovahimba women (Kunene Region, Northern Namibia) and the Palaeozoic Bokkeveld Group deposits of the Cape Supergroup (Western Cape Province, South Africa). We employ visible spectroscopy, energy-dispersive X-ray fluorescence (ED-XRF), X-ray diffraction (XRD) and granulometric analyses to characterise ochre samples. The capacity of ochre to inhibit the susceptibility of humans to the harmful effects of exposure to ultraviolet radiation (UVR) is confirmed and the mechanisms implicated in the efficacy of ochre as a sunscreen identified. It is posited that the habitual application of ochre may have represented a crucial innovation for MSA humans by limiting the adverse effects of ultraviolet exposure. This may have facilitated the colonisation of geographic regions largely unfavourable to the constitutive skin colour of newly arriving populations.
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Affiliation(s)
- Riaan F. Rifkin
- Institute for Archaeology, History, Culture and Religion, University of Bergen, Bergen, Norway
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Laure Dayet
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche, University of Bordeaux, Pessac, France
| | - Alain Queffelec
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche, University of Bordeaux, Pessac, France
| | - Beverley Summers
- Photobiology Laboratory, Department of Pharmacy, University of Limpopo, Medunsa, South Africa
| | - Marlize Lategan
- Photobiology Laboratory, Department of Pharmacy, University of Limpopo, Medunsa, South Africa
| | - Francesco d’Errico
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche, University of Bordeaux, Pessac, France
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11
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Abstract
Age-related macular degeneration (AMD) is the leading cause of blindness among older adults in the developed world. Although the pathological mechanisms have not been definitively elucidated, evidence suggests a key role for mitochondrial (mt) dysfunction. The current study used our unique collection of human retinal samples graded for the donor's stage of AMD to address fundamental questions about mtDNA damage in the retina. To evaluate the distribution of mtDNA damage in the diseased retina, damage in the retinal pigment epithelium (RPE) and neural retina from individual donors were compared. To directly test a long-held belief that the macula is selectively damaged with AMD, RPE mtDNA damage was measured in the macula and peripheral sections from individual donors. Small segments of the entire mt genome were examined to determine whether specific regions are preferentially damaged. Our results show that mtDNA damage is limited to the RPE, equivalent mtDNA damage is found in the macular and peripheral RPE, and sites of damage are localized to regions of the mt genome that may impact mt function. These results provide a scientific basis for targeting the RPE mitochondria with therapies that protect and enhance mt function as a strategy for combating AMD.
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12
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Hao XD, Chen P, Wang Y, Li SX, Xie LX. Mitochondrial DNA copy number, but not haplogroup is associated with keratoconus in Han Chinese population. Exp Eye Res 2015; 132:59-63. [PMID: 25613073 DOI: 10.1016/j.exer.2015.01.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 12/31/2014] [Accepted: 01/18/2015] [Indexed: 10/24/2022]
Abstract
Oxidative stress may play a role in the pathogenesis of keratoconus (KC). Mitochondrial DNA (mtDNA) is closely related to mitochondrion function, and variations may affect the generation of reactive oxygen species (ROS) and be involved in the pathogenesis of KC. To test whether mtDNA background and copy number confer genetic susceptibility to KC in the Han Chinese population, we performed this association study. We analyzed mtDNA sequence variations in 210 KC patients and 309 matched individuals from China, and classified each subject by haplogroup. Mitochondrial DNA copy number was measured in a subset of these subjects (193 patients and 103 controls). Comparison of matrilineal components of the cases and control populations revealed no significant difference. However, measurement of mtDNA copy number showed that KC patients had significantly lower mtDNA copy numbers than controls (P = 0.0002), even when age, gender, and mtDNA background were considered. Our results suggest that mtDNA copy number, but not haplogroup, is associated with keratoconus, and may contribute to its pathogenesis.
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Affiliation(s)
- Xiao-Dan Hao
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong Academy of Medical Sciences, Qingdao, China.
| | - Peng Chen
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong Academy of Medical Sciences, Qingdao, China.
| | - Ye Wang
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong Academy of Medical Sciences, Qingdao, China.
| | - Su-Xia Li
- Shandong Eye Hospital, Shandong Eye Institute, Shandong Academy of Medical Sciences, Jinan, China.
| | - Li-Xin Xie
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong Academy of Medical Sciences, Qingdao, China.
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13
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Lucas RM, Norval M, Neale RE, Young AR, de Gruijl FR, Takizawa Y, van der Leun JC. The consequences for human health of stratospheric ozone depletion in association with other environmental factors. Photochem Photobiol Sci 2015; 14:53-87. [DOI: 10.1039/c4pp90033b] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Ozone depletion, climate and human health.
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Affiliation(s)
- R. M. Lucas
- National Centre for Epidemiology and Population Health
- The Australian National University
- Canberra 2601
- Australia
- Telethon Kids Institute
| | - M. Norval
- Biomedical Sciences
- University of Edinburgh Medical School
- Edinburgh EH8 9AG
- UK
| | - R. E. Neale
- QIMR Berghofer Medical Research Institute
- Brisbane 4029
- Australia
| | - A. R. Young
- King's College London (KCL)
- St John's Institute of Dermatology
- London SE1 9RT
- UK
| | - F. R. de Gruijl
- Department of Dermatology
- Leiden University Medical Centre
- NL-2300 RC Leiden
- The Netherlands
| | - Y. Takizawa
- Akita University Graduate School of Medicine
- Akita Prefecture
- Japan
- National Institute for Minamata Diseases
- Kumamoto Prefecture
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