1
|
Zhou X, Backman LJ, Danielson P. Activation of NF-κB signaling via cytosolic mitochondrial RNA sensing in kerotocytes with mitochondrial DNA common deletion. Sci Rep 2021; 11:7360. [PMID: 33795727 PMCID: PMC8016944 DOI: 10.1038/s41598-021-86522-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 03/16/2021] [Indexed: 02/01/2023] Open
Abstract
Scar formation as a result of corneal wound healing is a leading cause of blindness. It is a challenge to understand why scar formation is more likely to occur in the central part of the cornea as compared to the peripheral part. The purpose of this study was to unravel the underlying mechanisms. We applied RNA-seq to uncover the differences of expression profile in keratocytes in the central/peripheral part of the cornea. The relative quantity of mitochondrial RNA was measured by multiplex qPCR. The characterization of mitochondrial RNA in the cytoplasm was confirmed by immunofluoresence microscope and biochemical approach. Gene expression was analyzed by western blot and RT qPCR. We demonstrate that the occurrence of mitochondrial DNA common deletion is greater in keratocytes from the central cornea as compared to those of the peripheral part. The keratocytes with CD have elevated oxidative stress levels, which leads to the leakage of mitochondrial double-stranded RNA into the cytoplasm. The cytoplasmic mitochondrial double-stranded RNA is sensed by MDA5, which induces NF-κB activation. The NF-κB activation thereafter induces fibrosis-like extracellular matrix expressions and IL-8 mRNA transcription. These results provide a novel explanation of the different clinical outcome in different regions of the cornea during wound healing.
Collapse
Affiliation(s)
- Xin Zhou
- grid.12650.300000 0001 1034 3451Department of Integrative Medical Biology, Umeå University, 90187 Umeå, Sweden
| | - Ludvig J. Backman
- grid.12650.300000 0001 1034 3451Department of Integrative Medical Biology, Umeå University, 90187 Umeå, Sweden ,grid.12650.300000 0001 1034 3451Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, 90187 Umeå, Sweden
| | - Patrik Danielson
- grid.12650.300000 0001 1034 3451Department of Integrative Medical Biology, Umeå University, 90187 Umeå, Sweden ,grid.12650.300000 0001 1034 3451Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Ahmadi M, Golalipour M, Samaei NM. Mitochondrial Common Deletion Level in Blood: New Insight Into the Effects of Age and Body Mass Index. Curr Aging Sci 2020; 11:250-254. [PMID: 30714539 PMCID: PMC6635417 DOI: 10.2174/1874609812666190201163421] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 01/06/2019] [Accepted: 01/25/2019] [Indexed: 01/07/2023]
Abstract
BACKGROUND Age-related decrease in mitochondrial activity has been reported in several tissues. Reactive Oxygen Species (ROS) produced from defected mitochondria lead to aging and accumulate through time. However, studies about the mitochondrial DNA mutation level in blood are contradictory. Other lifestyle factors may modify the effects of age in post-mitotic tissues such as blood. The BMI represents the sum of the various lifestyle factors. OBJECTIVE We proposed that age, obesity and mtDNA deletion are three ROS producing factors, which may interact with each other and induce senescence. METHODS In a cross-sectional study, 172 male and female volunteers without known mitochondrial diseases were selected and the presence of common mitochondrial 4977bp deletion (ΔmtDNA4977) evaluated using Nested-PCR. RESULTS Our results showed that a high percentage of samples (54.06%) harbor common deletion in blood. Furthermore, both BMI and the ΔmtDNA4977 levels significantly decrease with age. The chronological age, BMI and ΔmtDNA4977 reciprocally affect each other. CONCLUSION Our data suggest that age affects purifying selection and BMI, which may influence the relative level of the mtDNA common deletion in blood.
Collapse
Affiliation(s)
- Mahboube Ahmadi
- Department of Biology, School of Basic Sciences, Golestan University, Gorgan, Iran
| | - Masoud Golalipour
- Cellular and Molecular Research Center, Golestan University of Medical Sciences, Gorgan, Iran.,Department of Medical Genetics, Faculty of Advanced Medical Technologies, Golestan University of Medical Sciences, Gorgan, Iran
| | - Nader M Samaei
- Department of Medical Genetics, Faculty of Advanced Medical Technologies, Golestan University of Medical Sciences, Gorgan, Iran
| |
Collapse
|
4
|
Massanella M, Karris MY, Pérez-Santiago J, Yek C, Vitomirov A, Mehta SR. Analyses of Mitochondrial DNA and Immune Phenotyping Suggest Accelerated T-Cell Turnover in Treated HIV. J Acquir Immune Defic Syndr 2019; 79:399-406. [PMID: 30312276 DOI: 10.1097/qai.0000000000001824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND HIV infection is associated with premature aging, and mitochondrial integrity is compromised during the aging process. Because mitochondrial toxicity is a consequence of antiretroviral therapies (ARTs), we hypothesized HIV and long-term ART would correlate with immunosenescence and mitochondrial DNA (mtDNA) pathology. SETTING Thirteen older HIV-infected individuals (aged >40 years) with virologic suppression (stratified by duration of ART) were compared with 10 uninfected controls well-matched for age. METHODS Peripheral blood T-cells were immunophenotyped to measure immune activation, proliferation, and immunosenescence in subsets. mtDNA copies per cell and the relative abundance of mtDNA carrying the "common deletion" (RACD) were quantified by droplet digital polymerase chain reaction. RESULTS Immune activation was higher in HIV-infected individuals than HIV-uninfected individuals in mature CD4 T-cell subsets (CD4TTM P = 0.025, CD4TEM P = 0.0020) regardless of ART duration. Cell populations from uninfected individuals were more likely to be more senescent populations in mature CD4 T-cell subsets (TTM P = 0.017), and CD8 (CD8TEMRA+ P = 0.0026). No differences were observed in mtDNA or RACD levels in any CD4 T-cell subsets, while CD8TSCM of infected individuals trended to have more mtDNA (P = 0.057) and reduced RACD (P = 0.0025). CONCLUSIONS HIV-infected individuals demonstrated increased immune activation, but reduced senescence in more mature T-cell subsets. Increased mtDNA content and lower RACD in CD8TSCM suggest immune activation driven turnover of these cells in HIV-infected persons.
Collapse
Affiliation(s)
- Marta Massanella
- Department of Medicine, University of California San Diego, CA.,Department of Microbiology, Infectiology and Immunology, Centre de Recherche du CHUM, Universite[Combining Acute Accent] de Montre[Combining Acute Accent]al, Montre[Combining Acute Accent]al, QC, Canada
| | - Maile Y Karris
- Department of Medicine, University of California San Diego, CA
| | - Josué Pérez-Santiago
- Department of Medicine, University of California San Diego, CA.,Comprehensive Cancer Center, University of Puerto Rico, San Juan, PR
| | - Christina Yek
- Department of Medicine, University of California San Diego, CA.,University of Texas Southwestern Medical Center, Dallas, TX
| | | | - Sanjay R Mehta
- Department of Medicine, University of California San Diego, CA.,Department of Pathology, University of California San Diego, CA.,Veterans Affairs Medical Center, San Diego, CA
| |
Collapse
|
5
|
Han B, Zhou T, Tu Y, Wang T, He Z, Li Y, Yuan J, Yang X, Sun H. Correlation between mitochondrial DNA 4977 bp deletion and presbycusis: A system review and meta-analysis. Medicine (Baltimore) 2019; 98:e16302. [PMID: 31277167 PMCID: PMC6635239 DOI: 10.1097/md.0000000000016302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE Researchers have evaluated the associations between mitochondrial DNA (mtDNA) 4977 bp deletion and presbycusis. This study aimed to assess the differences of mtDNA 4977 bp deletion between presbycusis patients and controls by conducting a meta-analysis of published studies. METHODS Databases, including PubMed, Embase, Web of Science, China National Knowledge Infrastructure (CNKI), and Wanfang Data were searched to collect case-control studies on the correlation between mitochondrial DNA 4977 bp deletion and presbycusis. The research findings of related articles were collected according to the inclusion criteria. Pooled odds ratios (ORs) and corresponding confidence intervals (CIs) were calculated. Meanwhile, subgroup analysis was performed to examine the source of heterogeneity. Revman 5.3 and Stata 12.0 software were used for data synthesis. RESULTS Eight English and Chinese studies were included in the meta-analysis, the results of which showed that mitochondrial DNA 4977 bp deletion could increase the risk of presbycusis (OR = 8.16, 95% CI: 3.51-18.99), and the difference was statistically significant (P <. 01). Analysis of the polled OR showed the incidence of mtDNA 4977 bp deletion was 8.50 times higher in Asians with presbycusis than in the control group. And the OR in the studies of occidentals was 7.24. Sample source analysis was also performed with the sample source divided by temporal bone source and other sources (hair and blood). The OR was 4.18 and 22.36 for the temporal bone and other sources, respectively. CONCLUSION Mitochondrial DNA 4977 bp deletion could increase the risk of presbycusis.
Collapse
Affiliation(s)
- Baoai Han
- Departments of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei
- Public Laboratory, Key Laboratory of Breast Cancer Prevention and Therapy, Ministry of Education, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin Medical University, Tianjin, China
| | - Tao Zhou
- Departments of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei
| | - Yaqin Tu
- Departments of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei
| | - Tian Wang
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA
| | - Zuhong He
- Departments of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei
| | - Yongqin Li
- Departments of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei
| | - Jie Yuan
- Departments of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei
| | - Xiuping Yang
- Departments of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei
| | - Haiying Sun
- Departments of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA
| |
Collapse
|
6
|
Du ZD, He L, Tu C, Guo XA, Yu S, Liu K, Gong S. Mitochondrial DNA 3,860-bp Deletion Increases with Aging in the Auditory Nervous System of C57BL/6J Mice. ORL J Otorhinolaryngol Relat Spec 2019; 81:92-100. [PMID: 31129670 DOI: 10.1159/000499475] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 03/08/2019] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS Mitochondrial DNA (mtDNA) is sensitive to oxidative damage during aging, which can result in mtDNA mutations. A previous study reported that a 3,860-bp mtDNA deletion, similar to a 4,977-bp mtDNA deletion in humans, is also common occurrence in murine tissues, and increases in the brain and liver with aging. However, no previous study evaluated both topics in the murine auditory nervous system. METHODS We compared mtDNA oxidative damage, mitochondrial ultrastructural changes, and the frequency of the 3,860-bp deletion in the peripheral (spiral ganglion, SG) and central (auditory cortex, AC) auditory nervous system of C57BL/6J mice aged 2, 12, and 18 months. RESULTS We found that the threshold of auditory brainstem response increased with age along with the signal of 8-hydroxy-2'-deoxyguanosine - a marker of DNA oxidative damage - in the mitochondria of SG and AC neurons. The mitochondrial ultrastructural damage also increased with aging in the SG and AC neurons. Moreover, the relative amount of mtDNA 3,860-bp deletion in 12- and 18-month-old mice was significantly higher in the SG and AC as compared to 2-month-old mice. CONCLUSION These results suggest that the mtDNA 3,860-bp deletion is common in the auditory nervous system of mice and increases with age and may contribute to age-related hearing loss.
Collapse
Affiliation(s)
- Zheng-De Du
- Department of Otorhinolaryngology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Lu He
- Department of Otorhinolaryngology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Chunmei Tu
- Department of Otorhinolaryngology, First People's Hospital of Jinan, Jinan, China
| | - Xiao-An Guo
- Department of Otorhinolaryngology, First Affiliated Hospital of China Medical University, Shenyang, China
| | - Shukui Yu
- Department of Otorhinolaryngology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Ke Liu
- Department of Otorhinolaryngology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Shusheng Gong
- Department of Otorhinolaryngology, Beijing Friendship Hospital, Capital Medical University, Beijing, China,
| |
Collapse
|
7
|
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.
Collapse
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
| |
Collapse
|
8
|
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.
Collapse
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.
| |
Collapse
|
9
|
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.
Collapse
|
10
|
Bahrehmand Namaghi I, Vaziri H. Sperm mitochondrial DNA deletion in Iranian infertiles with asthenozoospermia. Andrologia 2016; 49. [DOI: 10.1111/and.12627] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/05/2016] [Indexed: 12/24/2022] Open
Affiliation(s)
| | - H. Vaziri
- Department of Biology; Faculty of Sciences; University of Guilan; Rasht Iran
| |
Collapse
|
11
|
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.
Collapse
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.
| |
Collapse
|
12
|
Levin L, Mishmar D. A Genetic View of the Mitochondrial Role in Ageing: Killing Us Softly. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 847:89-106. [DOI: 10.1007/978-1-4939-2404-2_4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
13
|
Liu H, Han Y, Wang S, Wang H. Association between the mitochondrial DNA 4977 common deletion in the hair shaft and hearing loss in presbycusis. Mol Med Rep 2014; 11:1127-31. [PMID: 25373716 DOI: 10.3892/mmr.2014.2877] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 07/21/2014] [Indexed: 11/06/2022] Open
Abstract
The aim of the present study was to examine the role of the mitochondrial (mt) DNA common deletion (CD) 4977 (mtDNACD4977) in the hair shaft in patients with presbycusis. A total of 87 individuals with presbycusis and 95 normal‑hearing controls were selected based on strict audiometric criteria. Nested polymerase chain reaction (PCR), sequencing and quantitative (q)PCR were used to examine the expression levels of mtDNACD4977 in the hair shaft in presbycusis. Nested PCR of the hair shaft demonstrated that 8/95 cases with normal hearing were found to be positive for mtDNACD4977, as compared with 59/87 cases in the presbycusis group. The mtDNACD4977 was positive in 22/43 cases with mild‑to‑moderate hearing loss, 25/31 cases with moderate‑to‑severe, severe hearing loss, and 12/13 cases with profound deafness. Statistically significant differences in mtDNACD4977 expression were identified among all of the groups (P<0.001). The sequencing and qPCR assays demonstrated a trend towards an increase in the mean CD level of mtDNACD4977 with a more severe hearing loss at 8 kHz (r=0.778, P<0.001) and all ranges of frequency (r=0.858, P<0.001). In conclusion, the present study demonstrates a correlation between mtDNACD4977 in the human hair shaft and the severity of hearing loss in presbycusis.
Collapse
Affiliation(s)
- Hong Liu
- Department of Otorhinolaryngology Head and Neck Surgery, Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250000, P.R. China
| | - Yuechen Han
- Department of Otorhinolaryngology Head and Neck Surgery, Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250000, P.R. China
| | - Shuai Wang
- Department of Thoracic Surgery, Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250000, P.R. China
| | - Haibo Wang
- Department of Otorhinolaryngology Head and Neck Surgery, Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250000, P.R. China
| |
Collapse
|
14
|
Wang CH, Wu SB, Wu YT, Wei YH. Oxidative stress response elicited by mitochondrial dysfunction: implication in the pathophysiology of aging. Exp Biol Med (Maywood) 2013; 238:450-60. [PMID: 23856898 DOI: 10.1177/1535370213493069] [Citation(s) in RCA: 227] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Under normal physiological conditions, reactive oxygen species (ROS) serve as 'redox messengers' in the regulation of intracellular signalling, whereas excess ROS may induce irreversible damage to cellular components and lead to cell death by promoting the intrinsic apoptotic pathway through mitochondria. In the aging process, accumulation of mitochondria DNA mutations, impairment of oxidative phosphorylation as well as an imbalance in the expression of antioxidant enzymes result in further overproduction of ROS. This mitochondrial dysfunction-elicited ROS production axis forms a vicious cycle, which is the basis of mitochondrial free radical theory of aging. In addition, several lines of evidence have emerged recently to demonstrate that ROS play crucial roles in the regulation of cellular metabolism, antioxidant defence and posttranslational modification of proteins. We first discuss the oxidative stress responses, including metabolites redistribution and alteration of the acetylation status of proteins, in human cells with mitochondrial dysfunction and in aging. On the other hand, autophagy and mitophagy eliminate defective mitochondria and serve as a scavenger and apoptosis defender of cells in response to oxidative stress during aging. These scenarios mediate the restoration or adaptation of cells to respond to aging and age-related disorders for survival. In the natural course of aging, the homeostasis in the network of oxidative stress responses is disturbed by a progressive increase in the intracellular level of the ROS generated by defective mitochondria. Caloric restriction, which is generally thought to promote longevity, has been reported to enhance the efficiency of this network and provide multiple benefits to tissue cells. In this review, we emphasize the positive and integrative roles of mild oxidative stress elicited by mitochondria in the regulation of adaptation, anti-aging and scavenging pathway beyond their roles in the vicious cycle of mitochondrial dysfunction in the aging process.
Collapse
Affiliation(s)
- Chih-Hao Wang
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei 112, Taiwan
| | | | | | | |
Collapse
|
15
|
Kamenisch Y, Berneburg M. Mitochondrial CSA and CSB: Protein interactions and protection from ageing associated DNA mutations. Mech Ageing Dev 2013; 134:270-4. [DOI: 10.1016/j.mad.2013.03.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 03/05/2013] [Accepted: 03/25/2013] [Indexed: 12/31/2022]
|
16
|
Gendron SP, Bastien N, Mallet JD, Rochette PJ. The 3895-bp mitochondrial DNA deletion in the human eye: a potential involvement in corneal ageing and macular degeneration. Mutagenesis 2013; 28:197-204. [DOI: 10.1093/mutage/ges071] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
|
17
|
Saccà SC, Roszkowska AM, Izzotti A. Environmental light and endogenous antioxidants as the main determinants of non-cancer ocular diseases. Mutat Res 2013; 752:153-171. [PMID: 23337404 DOI: 10.1016/j.mrrev.2013.01.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 01/10/2013] [Accepted: 01/11/2013] [Indexed: 02/03/2023]
Abstract
The human eye is constantly exposed to sunlight and artificial lighting. Exogenous sources of reactive oxygen species (ROS) such as UV light, visible light, ionizing radiation, chemotherapeutics, and environmental toxins contribute to oxidative damage in ocular tissues. Long-term exposure to these insults places the aging eye at considerable risk for pathological consequences of oxidative stress. Furthermore, in eye tissues, mitochondria are an important endogenous source of ROS. Over time, all ocular structures, from the tear film to the retina, undergo oxidative stress, and therefore, the antioxidant defenses of each tissue assume the role of a safeguard against degenerative ocular pathologies. The ocular surface and cornea protect the other ocular tissues and are significantly exposed to oxidative stress of environmental origin. Overwhelming of antioxidant defenses in these tissues clinically manifests as pathologies including pterygium, corneal dystrophies, and endothelial Fuch's dystrophy. The crystalline lens is highly susceptible to oxidative damage in aging because its cells and their intracellular proteins are not turned over or replaced, thus providing the basis for cataractogenesis. The trabecular meshwork, which is the anterior chamber tissue devoted to aqueous humor drainage, has a particular susceptibility to mitochondrial oxidative injury that affects its endothelium and leads to an intraocular pressure increase that marks the beginning of glaucoma. Photo-oxidative stress can cause acute or chronic retinal damage. The pathogenesis of age-related macular degeneration involves oxidative stress and death of the retinal pigment epithelium followed by death of the overlying photoreceptors. Accordingly, converging evidence indicates that mutagenic mechanisms of environmental and endogenous sources play a fundamental pathogenic role in degenerative eye diseases.
Collapse
Affiliation(s)
- Sergio C Saccà
- Department of Head/Neck Pathologies, St Martino Hospital, Ophthalmology unit, Genoa, Italy
| | - Anna Maria Roszkowska
- Department of Specialized Surgery, University Hospital, Ophthalmology Unit, Messina, Italy
| | - Alberto Izzotti
- Department of Health Sciences, University of Genoa, Via A. Pastore 1, I-16132, Genoa, Italy.
| |
Collapse
|