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Yordi S, Cakir Y, Kalra G, Cetin H, Hu M, Abraham J, Reese J, Srivastava SK, Ehlers JP. Ellipsoid Zone Integrity and Visual Function in Dry Age-Related Macular Degeneration. J Pers Med 2024; 14:543. [PMID: 38793125 PMCID: PMC11122652 DOI: 10.3390/jpm14050543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 05/08/2024] [Accepted: 05/16/2024] [Indexed: 05/26/2024] Open
Abstract
In this longitudinal retrospective image analysis, conducted on patients diagnosed with dry age-related macular degeneration (AMD) and 5 years of follow-up imaging data, the study aimed to investigate the relationship between ellipsoid zone (EZ) integrity on spectral domain optical coherence tomography (SD-OCT) and visual acuity (VA). Using a machine learning-enabled feature extraction tool, quantitative EZ parameters were derived from SD-OCT images. The analysis revealed significant correlations between EZ integrity metrics and VA. Eyes with excellent VA (≥20/25 Snellen) exhibited higher EZ integrity, including less EZ attenuation, thicker ellipsoid zone-retinal pigment epithelium (EZ-RPE) thickness, and higher EZ intensity, in contrast to eyes with worse VA (≤20/40 Snellen). Additionally, eyes with geographic atrophy (GA) in the foveal region displayed compromised EZ integrity compared to those without GA. Notably, baseline EZ integrity metrics were predictive of future VA loss. These findings suggest that quantitative SD-OCT measurements of EZ integrity could potentially detect early changes in dry AMD and serve as valuable indicators for predicting future functional outcomes. Furthermore, these measurements hold promise for use in clinical trial screenings, offering insights into the progression of the disease and its impact on visual acuity. This study underscores the importance of EZ integrity assessment in understanding and managing dry AMD.
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Affiliation(s)
- Sari Yordi
- The Tony and Leona Campane Center for Excellence in Image-Guided Surgery and Advanced Imaging Research, Cleveland Clinic, Cleveland, OH 44195, USA; (S.Y.); (Y.C.); (G.K.); (H.C.); (M.H.); (J.R.); (S.K.S.)
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44195, USA;
| | - Yavuz Cakir
- The Tony and Leona Campane Center for Excellence in Image-Guided Surgery and Advanced Imaging Research, Cleveland Clinic, Cleveland, OH 44195, USA; (S.Y.); (Y.C.); (G.K.); (H.C.); (M.H.); (J.R.); (S.K.S.)
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44195, USA;
| | - Gagan Kalra
- The Tony and Leona Campane Center for Excellence in Image-Guided Surgery and Advanced Imaging Research, Cleveland Clinic, Cleveland, OH 44195, USA; (S.Y.); (Y.C.); (G.K.); (H.C.); (M.H.); (J.R.); (S.K.S.)
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44195, USA;
| | - Hasan Cetin
- The Tony and Leona Campane Center for Excellence in Image-Guided Surgery and Advanced Imaging Research, Cleveland Clinic, Cleveland, OH 44195, USA; (S.Y.); (Y.C.); (G.K.); (H.C.); (M.H.); (J.R.); (S.K.S.)
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44195, USA;
| | - Ming Hu
- The Tony and Leona Campane Center for Excellence in Image-Guided Surgery and Advanced Imaging Research, Cleveland Clinic, Cleveland, OH 44195, USA; (S.Y.); (Y.C.); (G.K.); (H.C.); (M.H.); (J.R.); (S.K.S.)
- Department of Quantitative Health Sciences, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Joseph Abraham
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44195, USA;
| | - Jamie Reese
- The Tony and Leona Campane Center for Excellence in Image-Guided Surgery and Advanced Imaging Research, Cleveland Clinic, Cleveland, OH 44195, USA; (S.Y.); (Y.C.); (G.K.); (H.C.); (M.H.); (J.R.); (S.K.S.)
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44195, USA;
| | - Sunil K. Srivastava
- The Tony and Leona Campane Center for Excellence in Image-Guided Surgery and Advanced Imaging Research, Cleveland Clinic, Cleveland, OH 44195, USA; (S.Y.); (Y.C.); (G.K.); (H.C.); (M.H.); (J.R.); (S.K.S.)
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44195, USA;
| | - Justis P. Ehlers
- The Tony and Leona Campane Center for Excellence in Image-Guided Surgery and Advanced Imaging Research, Cleveland Clinic, Cleveland, OH 44195, USA; (S.Y.); (Y.C.); (G.K.); (H.C.); (M.H.); (J.R.); (S.K.S.)
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44195, USA;
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2
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Ulhaq ZS, Bittencourt GB, Soraya GV, Istifiani LA, Pamungkas SA, Ogino Y, Nurputra DK, Tse WKF. Association between glaucoma susceptibility with combined defects in mitochondrial oxidative phosphorylation and fatty acid beta oxidation. Mol Aspects Med 2024; 96:101238. [PMID: 38215610 DOI: 10.1016/j.mam.2023.101238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 11/08/2023] [Accepted: 11/28/2023] [Indexed: 01/14/2024]
Abstract
Glaucoma is one of the leading causes of visual impairment and blindness worldwide, and is characterized by the progressive damage of retinal ganglion cells (RGCs) and the atrophy of the optic nerve head (ONH). The exact cause of RGC loss and optic nerve damage in glaucoma is not fully understood. The high energy demands of these cells imply a higher sensitivity to mitochondrial defects. Moreover, it has been postulated that the optic nerve is vulnerable towards damage from oxidative stress and mitochondrial dysfunction. To investigate this further, we conducted a pooled analysis of mitochondrial variants related to energy production, specifically focusing on oxidative phosphorylation (OXPHOS) and fatty acid β-oxidation (FAO). Our findings revealed that patients carrying non-synonymous (NS) mitochondrial DNA (mtDNA) variants within the OXPHOS complexes had an almost two-fold increased risk of developing glaucoma. Regarding FAO, our results demonstrated that longer-chain acylcarnitines (AC) tended to decrease, while shorter-chain AC tended to increase in patients with glaucoma. Furthermore, we observed that the knocking down cpt1a (a key rate-limiting enzyme involved in FAO) in zebrafish induced a degenerative process in the optic nerve and RGC, which resembled the characteristics observed in glaucoma. In conclusion, our study provides evidence that genes encoding mitochondrial proteins involved in energy metabolisms, such as OXPHOS and FAO, are associated with glaucoma. These findings contribute to a better understanding of the molecular mechanisms underlying glaucoma pathogenesis and may offer potential targets for therapeutic interventions in the future.
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Affiliation(s)
- Zulvikar Syambani Ulhaq
- Research Center for Pre-clinical and Clinical Medicine, National Research and Innovation Agency Republic of Indonesia, Cibinong, Indonesia; Laboratory of Developmental Disorders and Toxicology, Center for Promotion of International Education and Research, Faculty of Agriculture, Kyushu University, Fukuoka, Japan.
| | - Guido Barbieri Bittencourt
- Departamento de Psicologia Experimental, Instituto de Psicologia, Universidade de São Paulo, São Paulo, Brazil
| | - Gita Vita Soraya
- Department of Biochemistry, Faculty of Medicine, Hasanuddin University, Makassar, Indonesia
| | - Lola Ayu Istifiani
- Department of Nutrition, Faculty of Health Sciences, Brawijaya University, Malang, Indonesia
| | | | - Yukiko Ogino
- Laboratory of Aquatic Molecular Developmental Biology, Center for Promotion of International Education and Research, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
| | | | - William Ka Fai Tse
- Laboratory of Developmental Disorders and Toxicology, Center for Promotion of International Education and Research, Faculty of Agriculture, Kyushu University, Fukuoka, Japan.
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3
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Dutta D, Kanca O, Byeon SK, Marcogliese PC, Zuo Z, Shridharan RV, Park JH, Lin G, Ge M, Heimer G, Kohler JN, Wheeler MT, Kaipparettu BA, Pandey A, Bellen HJ. A defect in mitochondrial fatty acid synthesis impairs iron metabolism and causes elevated ceramide levels. Nat Metab 2023; 5:1595-1614. [PMID: 37653044 PMCID: PMC11151872 DOI: 10.1038/s42255-023-00873-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Accepted: 07/21/2023] [Indexed: 09/02/2023]
Abstract
In most eukaryotic cells, fatty acid synthesis (FAS) occurs in the cytoplasm and in mitochondria. However, the relative contribution of mitochondrial FAS (mtFAS) to the cellular lipidome is not well defined. Here we show that loss of function of Drosophila mitochondrial enoyl coenzyme A reductase (Mecr), which is the enzyme required for the last step of mtFAS, causes lethality, while neuronal loss of Mecr leads to progressive neurodegeneration. We observe a defect in Fe-S cluster biogenesis and increased iron levels in flies lacking mecr, leading to elevated ceramide levels. Reducing the levels of either iron or ceramide suppresses the neurodegenerative phenotypes, indicating an interplay between ceramide and iron metabolism. Mutations in human MECR cause pediatric-onset neurodegeneration, and we show that human-derived fibroblasts display similar elevated ceramide levels and impaired iron homeostasis. In summary, this study identifies a role of mecr/MECR in ceramide and iron metabolism, providing a mechanistic link between mtFAS and neurodegeneration.
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Affiliation(s)
- Debdeep Dutta
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Oguz Kanca
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Seul Kee Byeon
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Paul C Marcogliese
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
- Department of Biochemistry & Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Zhongyuan Zuo
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Rishi V Shridharan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Jun Hyoung Park
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Guang Lin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Ming Ge
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Gali Heimer
- Pediatric Neurology Unit, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Ramat Gan, Israel
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Jennefer N Kohler
- Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Matthew T Wheeler
- Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Benny A Kaipparettu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Akhilesh Pandey
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
- Manipal Academy of Higher Education, Manipal, India
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA.
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4
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Yin Y, Wu S, Niu L, Huang S. Atonal homolog 7 (ATOH7) confers neuroprotection for photoreceptor cells in glaucoma via inhibition of the notch pathway. J Neurochem 2023; 166:847-861. [PMID: 37526008 DOI: 10.1111/jnc.15905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 06/13/2023] [Accepted: 06/20/2023] [Indexed: 08/02/2023]
Abstract
Single-cell RNA sequencing (scRNA-seq) technologies enable the profiling and analysis of the transcriptomes of single cells and hold promise for clarifying gene mechanisms at single-cell resolution. We based this study on scRNA-seq data to reveal glaucoma-related genes and downstream pathways with neuroprotection effects. The scRNA-seq datasets related to glaucoma of retinal tissue samples of human beings and Atonal Homolog 7 (ATOH7)-null mice were obtained from the GEO database. The 74 top marker genes and 20 cell clusters were obtained in human retinal tissue samples. The key gene ATOH7 was found after the intersection with genes from GeneCards data. In the ATOH7-null mouse retinal tissue samples, pseudotime inference demonstrated significant changes in cell differentiation. Moreover, mouse retinal photoreceptor cells (PRCs) were cultured and treated with lentivirus carrying oe-ATOH7 alone or in combination with Notch signaling pathway activator Jagged-1/FC, after which cell biological functions were determined. The involvement of ATOH7 in glaucoma was identified through regulating PRCs. Furthermore, ATOH7 conferred neuroprotection in PRCs in glaucoma by mediating the Notch signaling pathway. In vitro data confirmed that ATOH7 overexpression promoted the differentiation of PRCs and inhibited their apoptosis by suppressing the Notch signaling pathway. The evidence provided by our study highlighted the involvement of ATOH7 in the blockade of the Notch signaling pathway, resulting in the neuroprotection for PRCs in glaucoma.
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Affiliation(s)
- Yuan Yin
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, People's Republic of China
| | - Shuai Wu
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, People's Republic of China
| | - Lingzhi Niu
- Department of Ophthalmology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, People's Republic of China
| | - Shiwei Huang
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, People's Republic of China
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5
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Nozawa N, Noguchi M, Shinno K, Saito T, Asada A, Ishii T, Takahashi K, Ishizuka M, Ando K. 5-Aminolevulinic acid bypasses mitochondrial complex I deficiency and corrects physiological dysfunctions in Drosophila. Hum Mol Genet 2023; 32:2611-2622. [PMID: 37364055 PMCID: PMC10407699 DOI: 10.1093/hmg/ddad092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 04/15/2023] [Accepted: 06/15/2023] [Indexed: 06/28/2023] Open
Abstract
Complex I (CI) deficiency in mitochondrial oxidative phosphorylation (OXPHOS) is the most common cause of mitochondrial diseases, and limited evidence-based treatment options exist. Although CI provides the most electrons to OXPHOS, complex II (CII) is another entry point of electrons. Enhancement of this pathway may compensate for a loss of CI; however, the effects of boosting CII activity on CI deficiency are unclear at the animal level. 5-Aminolevulinic acid (5-ALA) is a crucial precursor of heme, which is essential for CII, complex III, complex IV (CIV) and cytochrome c activities. Here, we show that feeding a combination of 5-ALA hydrochloride and sodium ferrous citrate (5-ALA-HCl + SFC) increases ATP production and suppresses defective phenotypes in Drosophila with CI deficiency. Knockdown of sicily, a Drosophila homolog of the critical CI assembly protein NDUFAF6, caused CI deficiency, accumulation of lactate and pyruvate and detrimental phenotypes such as abnormal neuromuscular junction development, locomotor dysfunctions and premature death. 5-ALA-HCl + SFC feeding increased ATP levels without recovery of CI activity. The activities of CII and CIV were upregulated, and accumulation of lactate and pyruvate was suppressed. 5-ALA-HCl + SFC feeding improved neuromuscular junction development and locomotor functions in sicily-knockdown flies. These results suggest that 5-ALA-HCl + SFC shifts metabolic programs to cope with CI deficiency. Bullet outline 5-Aminolevulinic acid (5-ALA-HCl + SFC) increases ATP production in flies with complex I deficiency.5-ALA-HCl + SFC increases the activities of complexes II and IV.5-ALA-HCl + SFC corrects metabolic abnormalities and suppresses the detrimental phenotypes caused by complex I deficiency.
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Affiliation(s)
- Naoko Nozawa
- Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Tokyo 192-0397, Japan
- Division of Pharmaceutical Research, SBI Pharmaceuticals Co., Ltd, Tokyo 106-6020, Japan
| | - Marie Noguchi
- Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Kanako Shinno
- Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Taro Saito
- Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Tokyo 192-0397, Japan
- Department of Biological Sciences, School of Science, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Akiko Asada
- Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Tokyo 192-0397, Japan
- Department of Biological Sciences, School of Science, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Takuya Ishii
- Division of Pharmaceutical Research, SBI Pharmaceuticals Co., Ltd, Tokyo 106-6020, Japan
- Medical- Engineering Collaboration and Innovation Office, National Cancer Center Hospital East, 6-5-1 Kashinoha, Kashiwa, Chiba 277-8577, Japan
| | - Kiwamu Takahashi
- Division of Pharmaceutical Research, SBI Pharmaceuticals Co., Ltd, Tokyo 106-6020, Japan
| | - Masahiro Ishizuka
- Division of Pharmaceutical Research, SBI Pharmaceuticals Co., Ltd, Tokyo 106-6020, Japan
| | - Kanae Ando
- Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Tokyo 192-0397, Japan
- Department of Biological Sciences, School of Science, Tokyo Metropolitan University, Tokyo 192-0397, Japan
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Cheramangalam RN, Anand T, Pandey P, Balasubramanian D, Varghese R, Singhal N, Jaiswal SN, Jaiswal M. Bendless is essential for PINK1-Park mediated Mitofusin degradation under mitochondrial stress caused by loss of LRPPRC. PLoS Genet 2023; 19:e1010493. [PMID: 37098042 PMCID: PMC10162545 DOI: 10.1371/journal.pgen.1010493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 05/05/2023] [Accepted: 04/03/2023] [Indexed: 04/26/2023] Open
Abstract
Cells under mitochondrial stress often co-opt mechanisms to maintain energy homeostasis, mitochondrial quality control and cell survival. A mechanistic understanding of such responses is crucial for further insight into mitochondrial biology and diseases. Through an unbiased genetic screen in Drosophila, we identify that mutations in lrpprc2, a homolog of the human LRPPRC gene that is linked to the French-Canadian Leigh syndrome, result in PINK1-Park activation. While the PINK1-Park pathway is well known to induce mitophagy, we show that PINK1-Park regulates mitochondrial dynamics by inducing the degradation of the mitochondrial fusion protein Mitofusin/Marf in lrpprc2 mutants. In our genetic screen, we also discover that Bendless, a K63-linked E2 conjugase, is a regulator of Marf, as loss of bendless results in increased Marf levels. We show that Bendless is required for PINK1 stability, and subsequently for PINK1-Park mediated Marf degradation under physiological conditions, and in response to mitochondrial stress as seen in lrpprc2. Additionally, we show that loss of bendless in lrpprc2 mutant eyes results in photoreceptor degeneration, indicating a neuroprotective role for Bendless-PINK1-Park mediated Marf degradation. Based on our observations, we propose that certain forms of mitochondrial stress activate Bendless-PINK1-Park to limit mitochondrial fusion, which is a cell-protective response.
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Affiliation(s)
| | - Tarana Anand
- Tata Institute of Fundamental Research, Hyderabad, India
| | - Priyanka Pandey
- CSIR–Centre For Cellular and Molecular Biology, Hyderabad, India
| | | | - Reshmi Varghese
- CSIR–Centre For Cellular and Molecular Biology, Hyderabad, India
| | - Neha Singhal
- Tata Institute of Fundamental Research, Hyderabad, India
| | | | - Manish Jaiswal
- Tata Institute of Fundamental Research, Hyderabad, India
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Natural History of the Relative Ellipsoid Zone Reflectivity in Age-Related Macular Degeneration. Ophthalmol Retina 2022; 6:1165-1172. [PMID: 35709960 DOI: 10.1016/j.oret.2022.06.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 05/08/2022] [Accepted: 06/06/2022] [Indexed: 01/06/2023]
Abstract
PURPOSE Relative ellipsoid zone reflectivity (rEZR) has been reported to be reduced in intermediate age-related macular degeneration (iAMD). However, longitudinal changes in rEZR remain unknown. This study investigated the natural history of rEZR in iAMD and its association with risk factors for disease progression, including the presence or extent of drusen volume, reticular pseudodrusen (RPD), and pigmentary abnormalities (PAs). DESIGN Longitudinal observational study. PARTICIPANTS Subjects with bilateral large drusen. METHODS Spectral-domain (SD) OCT images of both eyes from each participant were obtained every 6 months for 3 years. Using an automated rEZR determination approach, the average rEZR of the central 20° macula was determined for each SD-OCT volume scan. Linear mixed models were used to determine the rate of change in rEZR with age (using the cross-sectional data at baseline) and over time (longitudinal data) and the interactions between the rate of rEZR changes with AMD risk factors at baseline. MAIN OUTCOME MEASURES Relative ellipsoid zone reflectivity and its rate of change with age and over time. RESULTS A total of 280 eyes from 140 individuals with bilateral large drusen were included in this study. Cross-sectional data showed that rEZR reduced with increasing age (-8.4 arbitrary units [AUs] per decade; 95% confidence interval [CI], -11.5 to -5.2; P < 0.001). Longitudinal data showed that, on average, rEZR declined at a rate of -2.1 AU per year (95% CI, -2.6 to -1.6 AU per year; P < 0.001). Larger RPD area (P = 0.042) at baseline was associated with a faster rate of rEZR decline over time, whereas the presence of PAs and the drusen volume at baseline showed no significant association with rEZR decline over time (P = 0.068 and P = 0.529, respectively). CONCLUSIONS The rEZR significantly reduces over 3 years in subjects with iAMD, and both the presence and increasing extent of coexistent RPD at baseline are associated with a faster rate of decline. These findings warrant further studies to understand the value of rEZR as a biomarker of AMD progression.
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8
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CGG repeat expansion in NOTCH2NLC causes mitochondrial dysfunction and progressive neurodegeneration in Drosophila model. Proc Natl Acad Sci U S A 2022; 119:e2208649119. [PMID: 36191230 PMCID: PMC9565157 DOI: 10.1073/pnas.2208649119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Neuronal intranuclear inclusion disease (NIID) is a neuromuscular/neurodegenerative disease caused by the expansion of CGG repeats in the 5' untranslated region (UTR) of the NOTCH2NLC gene. These repeats can be translated into a polyglycine-containing protein, uN2CpolyG, which forms protein inclusions and is toxic in cell models, albeit through an unknown mechanism. Here, we established a transgenic Drosophila model expressing uN2CpolyG in multiple systems, which resulted in progressive neuronal cell loss, locomotor deficiency, and shortened lifespan. Interestingly, electron microscopy revealed mitochondrial swelling both in transgenic flies and in muscle biopsies of individuals with NIID. Immunofluorescence and immunoelectron microscopy showed colocalization of uN2CpolyG with mitochondria in cell and patient samples, while biochemical analysis revealed that uN2CpolyG interacted with a mitochondrial RNA binding protein, LRPPRC (leucine-rich pentatricopeptide repeat motif-containing protein). Furthermore, RNA sequencing (RNA-seq) analysis and functional assays showed down-regulated mitochondrial oxidative phosphorylation in uN2CpolyG-expressing flies and NIID muscle biopsies. Finally, idebenone treatment restored mitochondrial function and alleviated neurodegenerative phenotypes in transgenic flies. Overall, these results indicate that transgenic flies expressing uN2CpolyG recapitulate key features of NIID and that reversing mitochondrial dysfunction might provide a potential therapeutic approach for this disorder.
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9
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Saßmannshausen M, Behning C, Isselmann B, Schmid M, Finger RP, Holz FG, Schmitz-Valckenberg S, Pfau M, Thiele S. Relative ellipsoid zone reflectivity and its association with disease severity in age-related macular degeneration: a MACUSTAR study report. Sci Rep 2022; 12:14933. [PMID: 36056113 PMCID: PMC9440143 DOI: 10.1038/s41598-022-18875-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 08/22/2022] [Indexed: 12/03/2022] Open
Abstract
Quantification of the relative ellipsoid zone reflectivity (rEZR) might be a structural surrogate parameter for an early disease progression in the context of age-related macular degeneration (AMD). Within the European multicenter, cross-sectional MACUSTAR study, we have devised an automatic approach to determine the mean rEZR [arbitrary units, AU] at two independent visits in SD-OCT volume scans in study participants. Linear mixed-effects models were applied to analyze the association of AMD stage and AMD associated high-risk features including presence of pigmentary abnormalities, reticular pseudodrusen (RPD), volume of the retinal-pigment-epithelial-drusenoid-complex (RPEDC) with the rEZR. Intra-class correlation coefficients (ICC) were determined for rEZR reliability analysis. Within the overall study cohort (301 participants), we could observe decreased rEZR values (coefficient estimate ± standard error) of - 8.05 ± 2.44 AU (p = 0.0011) in the intermediate and of - 22.35 ± 3.28 AU (p < 0.0001) in the late AMD group. RPD presence was significantly associated with the rEZR in iAMD eyes (- 6.49 ± 3.14 AU; p = 0.0403), while there was a good ICC of 0.846 (95% confidence interval: 0.809; 0.876) in the overall study cohort. This study showed an association of rEZR with increasing disease severity and the presence of iAMD high-risk features. Further studies are necessary to evaluate the rEZR's value as a novel biomarker for AMD and disease progression.
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Affiliation(s)
- Marlene Saßmannshausen
- Department of Ophthalmology, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
- GRADE Reading Center, University of Bonn, Bonn, Germany
| | - Charlotte Behning
- Institute for Medical Biometry, Informatics and Epidemiology, University of Bonn, Bonn, Germany
| | - Ben Isselmann
- Department of Ophthalmology, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Matthias Schmid
- Institute for Medical Biometry, Informatics and Epidemiology, University of Bonn, Bonn, Germany
| | - Robert P Finger
- Department of Ophthalmology, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Frank G Holz
- Department of Ophthalmology, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
- GRADE Reading Center, University of Bonn, Bonn, Germany
| | - Steffen Schmitz-Valckenberg
- Department of Ophthalmology, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
- GRADE Reading Center, University of Bonn, Bonn, Germany
- John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
| | - Maximilian Pfau
- Department of Ophthalmology, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
- GRADE Reading Center, University of Bonn, Bonn, Germany
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, Bethesda, MD, USA
| | - Sarah Thiele
- Department of Ophthalmology, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany.
- GRADE Reading Center, University of Bonn, Bonn, Germany.
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10
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Kam JH, Hogg C, Fosbury R, Shinhmar H, Jeffery G. Mitochondria are specifically vulnerable to 420nm light in drosophila which undermines their function and is associated with reduced fly mobility. PLoS One 2021; 16:e0257149. [PMID: 34478469 PMCID: PMC8415596 DOI: 10.1371/journal.pone.0257149] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 08/24/2021] [Indexed: 01/05/2023] Open
Abstract
Increased blue light exposure has become a matter of concern as it has a range of detrimental effects, but the mechanisms remain unclear. Mitochondria absorb short wavelength light but have a specific absorbance at 420nm at the lower end of the human visual range. This 420nm absorption is probably due to the presence of porphyrin. We examine the impact of 420nm exposure on drosophila melanogaster mitochondria and its impact on fly mobility. Daily 15 mins exposures for a week significantly reduced mitochondrial complex activities and increased mitochondrial inner membrane permeability, which is a key metric of mitochondrial health. Adenosine triphosphate (ATP) levels were not significantly reduced and mobility was unchanged. There are multiple options for energy/time exposure combinations, but we then applied single 420nm exposure of 3h to increase the probability of an effect on ATP and mobility, and both were significantly reduced. ATP and mitochondrial membrane permeability recovered and over corrected at 72h post exposure. However, despite this, normal mobility did not return. Hence, the effect of short wavelengths on mitochondrial function is to reduce complex activity and increasing membrane permeability, but light exposure to reduce ATP and to translate into reduced mobility needs to be sustained.
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Affiliation(s)
- Jaimie Hoh Kam
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - Chris Hogg
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - Robert Fosbury
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - Harpreet Shinhmar
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - Glen Jeffery
- Institute of Ophthalmology, University College London, London, United Kingdom
- * E-mail:
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11
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cGMP-PKG dependent transcriptome in normal and degenerating retinas: Novel insights into the retinitis pigmentosa pathology. Exp Eye Res 2021; 212:108752. [PMID: 34478738 DOI: 10.1016/j.exer.2021.108752] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 06/25/2021] [Accepted: 08/25/2021] [Indexed: 12/26/2022]
Abstract
Retinitis Pigmentosa represents a group of genetic disorders that cause progressive vision loss via degeneration of photoreceptors, but there is in principle no treatment available. For any therapy development, a deeper comprehension of the disease-leading mechanism(s) at the molecular level is needed. Here we focused on the cGMP-PKG system, which has been suggested to be a driver in several models of the disease. To gain insights in its downstream signaling we manipulated the cGMP-PKG system with the aid of organotypic retinal explant cultures from either a mouse-based disease model, i.e. the rd1 mouse, or its healthy wild-type counterpart (wt), by adding different types of cGMP analogues to either inhibit or activate PKG in retinal explants from rd1 and wt, respectively. An RNA sequencing was then performed to study the cGMP-PKG dependent transcriptome. Expression changes of gene sets related to specific pathways or functions, that fulfilled criteria involving that the changes should match PKG activation and inhibition, were determined via bioinformatics. The analyses highlighted that several gene sets linked to oxidative phosphorylation and mitochondrial pathways were regulated by this enzyme system. Specifically, the expression of such pathway components was upregulated in the rd1 treated with PKG inhibitor and downregulated in the wt with PKG activator treatment, suggesting that cGMP-PKG act as a negative regulator in this context. Downregulation of energy production pathways may thus play an integral part in the mechanism behind the degeneration for at least several RP mutations.
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12
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Kizawa Y, Sekikawa T, Kageyama M, Tomobe H, Kobashi R, Yamada T. Effects of anthocyanin, astaxanthin, and lutein on eye functions: a randomized, double-blind, placebo-controlled study. J Clin Biochem Nutr 2021; 69:77-90. [PMID: 34376917 PMCID: PMC8325772 DOI: 10.3164/jcbn.20-149] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Accepted: 10/25/2020] [Indexed: 12/12/2022] Open
Abstract
We examined the effects of a test food containing anthocyanin, astaxanthin, and lutein on the eye function in healthy Japanese adults with eye fatigue after operating visual display terminals. Forty-four subjects were randomly but equally assigned to the active or placebo group. Two active or placebo capsules were taken once daily for 6 weeks. Accommodative function, tear film break-up time, visual acuity, the value of Schirmer's test, macular pigment optical density level, muscle hardness, and a questionnaire were evaluated before and after a 6-week intervention. Each group included 20 subjects in the efficacy analysis. The active group showed a significant improvement in the percentage of pupillary response of an average of both eyes and dominant eye pre- and post-visual display terminal operation at 6 weeks compared with the placebo group. Moreover, the active group showed a significant improvement in the scores of "A sensation of trouble in focusing the eyes" and "Difficulty in seeing objects in one's hand and nearby, or fine print" compared with the placebo group between before and after ingestion. Therefore, 6-weeks consumption of the test food inhibited a decrease in the accommodative function caused by visual display terminal operation (UMIN000036989).
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Affiliation(s)
- Yuki Kizawa
- BGG Japan Co., Ltd., 8F Ginza Kobikicho Building, 8-18-1 Ginza, Chuo-ku, Tokyo 104-0061, Japan
| | - Takahiro Sekikawa
- BGG Japan Co., Ltd., 8F Ginza Kobikicho Building, 8-18-1 Ginza, Chuo-ku, Tokyo 104-0061, Japan
| | - Masakatsu Kageyama
- DHC Corporation, Laboratories Division 2, 2-42 Hamada, Mihama-ku, Chiba-shi, Chiba, 261-0025, Japan
| | - Haruna Tomobe
- DHC Corporation, Laboratories Division 2, 2-42 Hamada, Mihama-ku, Chiba-shi, Chiba, 261-0025, Japan
| | - Riyo Kobashi
- DHC Corporation, Laboratories Division 2, 2-42 Hamada, Mihama-ku, Chiba-shi, Chiba, 261-0025, Japan
| | - Takahiro Yamada
- Ario Nishiarai Eye Clinic, 2F Ario Nishiarai, 1-20-1 Nishiarai Sakae-cho, Adachi-ku, Tokyo 123-0843, Japan
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13
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Datta S, Jaiswal M. Mitochondrial calcium at the synapse. Mitochondrion 2021; 59:135-153. [PMID: 33895346 DOI: 10.1016/j.mito.2021.04.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 03/28/2021] [Accepted: 04/13/2021] [Indexed: 12/15/2022]
Abstract
Mitochondria are dynamic organelles, which serve various purposes, including but not limited to the production of ATP and various metabolites, buffering ions, acting as a signaling hub, etc. In recent years, mitochondria are being seen as the central regulators of cellular growth, development, and death. Since neurons are highly specialized cells with a heavy metabolic demand, it is not surprising that neurons are one of the most mitochondria-rich cells in an animal. At synapses, mitochondrial function and dynamics is tightly regulated by synaptic calcium. Calcium influx during synaptic activity causes increased mitochondrial calcium influx leading to an increased ATP production as well as buffering of synaptic calcium. While increased ATP production is required during synaptic transmission, calcium buffering by mitochondria is crucial to prevent faulty neurotransmission and excitotoxicity. Interestingly, mitochondrial calcium also regulates the mobility of mitochondria within synapses causing mitochondria to halt at the synapse during synaptic transmission. In this review, we summarize the various roles of mitochondrial calcium at the synapse.
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Affiliation(s)
- Sayantan Datta
- Tata Institute of Fundamental Research, Hyderabad, India
| | - Manish Jaiswal
- Tata Institute of Fundamental Research, Hyderabad, India.
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14
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Cao X, An J, Cao Y, Lv J, Wang J, Ding Y, Lin X, Zhou X. EMC3 Is Essential for Retinal Organization and Neurogenesis During Mouse Retinal Development. Invest Ophthalmol Vis Sci 2021; 62:31. [PMID: 33605987 PMCID: PMC7900856 DOI: 10.1167/iovs.62.2.31] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 01/18/2021] [Indexed: 12/15/2022] Open
Abstract
Purpose We used a mouse model to explore the role of the endoplasmic reticulum membrane protein complex subunit 3 (EMC3) in mammalian retinal development. Methods The transcription pattern of Emc3 in C57BL/6 mice was analyzed by in situ hybridization. To explore the effects of EMC3 absence on retinal development, the Cre-loxP system was used to generate retina-specific Emc3 in knockout mice (Emc3flox/flox, Six3-cre+; CKO). Morphological changes in the retina of E13.5, E17.5, P0.5, and P7 mice were observed via hematoxylin and eosin staining. Immunofluorescence staining was used to assess protein distribution and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining to assess apoptosis changes. Proteins were identified and quantified by Western blotting and proteomic analysis. Electroretinogram (ERG), fundus color photography, and optical coherence tomography were performed on 5-week-old mice to evaluate retinal function and structure. Results The Emc3 mRNA was widely distributed in the whole retina during development. Loss of retinal EMC3 led to retinal rosette degeneration with mislocalization of cell junction molecules (β-catenin, N-cadherin, and zonula occludens-1) and polarity molecules (Par3 and PKCζ). Endoplasmic reticulum stress and TUNEL apoptosis signals were present in retinal rosette-forming cells. Although the absence of EMC3 promoted the production of photoreceptor cells, 5-week-old mice lost all visual function and had severe retinal morphological degeneration. Conclusions EMC3 regulates retinal structure by maintaining the polarity of retinal progenitor cells and regulating retinal cell apoptosis.
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Affiliation(s)
- Xiaowen Cao
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
| | - Jianhong An
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
| | - Yuqing Cao
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
| | - Juan Lv
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
| | - Jiawei Wang
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
| | - Yang Ding
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
| | - Xinhua Lin
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Xiangtian Zhou
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
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15
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Cheng YS, Linetsky M, Li H, Ayyash N, Gardella A, Salomon RG. 4-Hydroxy-7-oxo-5-heptenoic acid lactone can induce mitochondrial dysfunction in retinal pigmented epithelial cells. Free Radic Biol Med 2020; 160:719-733. [PMID: 32920040 PMCID: PMC7704664 DOI: 10.1016/j.freeradbiomed.2020.09.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 08/25/2020] [Accepted: 09/04/2020] [Indexed: 11/30/2022]
Abstract
Oxidation of docosahexaenoate (DHA)-containing phospholipids in the cell plasma membrane leads to release of the α,β-unsaturated aldehyde 4-hydroxy-7-oxo-5-heptenoic acid (HOHA) lactone which is capable of inducing retinal pigmented epithelial (RPE) cell dysfunction. Previously, HOHA lactone was shown to induce apoptosis and angiogenesis, and to activate the alternative complement pathway. RPE cells metabolize HOHA lactone through enzymatic conjugation with glutathione (GSH). Competing with this process is the adduction of HOHA lactone to protein lysyl residues generating 2-(ω-carboxyethyl)pyrrole (CEP) derivatives that have pathological relevance to age-related macular degeneration (AMD). We now find that HOHA lactone induces mitochondrial dysfunction. It decreases ATP levels, mitochondrial membrane potentials, enzymatic activities of mitochondrial complexes, depletes GSH and induces oxidative stress in RPE cells. The present study confirmed that pyridoxamine and other primary amines, which have been shown to scavenge γ-ketoaldehydes formed by carbohydrate or lipid peroxidation, are ineffective for scavenging the α,β-unsaturated aldehydes. Histidyl hydrazide (HH), that has both hydrazide and imidazole nucleophile functionalities, is an effective scavenger of HOHA lactone and it protects ARPE-19 cells against HOHA lactone-induced cytotoxicity. The HH α-amino group is not essential for this electrophile trapping activity. The Nα-acyl L-histidyl hydrazide derivatives with 2- to 7-carbon acyl groups with increasing lipophilicities are capable of maintaining the effectiveness of HH in protecting ARPE-19 cells against HOHA lactone toxicity, which potentially has therapeutic utility for treatment of age related eye diseases.
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Affiliation(s)
- Yu-Shiuan Cheng
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Mikhail Linetsky
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106, USA; Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Haoting Li
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Naji Ayyash
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Anthony Gardella
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Robert G Salomon
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106, USA; Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA.
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16
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Thiele S, Isselmann B, Pfau M, Holz FG, Schmitz-Valckenberg S, Wu Z, Guymer RH, Luu CD. Validation of an Automated Quantification of Relative Ellipsoid Zone Reflectivity on Spectral Domain-Optical Coherence Tomography Images. Transl Vis Sci Technol 2020; 9:17. [PMID: 33133775 PMCID: PMC7581490 DOI: 10.1167/tvst.9.11.17] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 09/24/2020] [Indexed: 11/24/2022] Open
Abstract
Purpose Relative ellipsoid zone reflectivity (rEZR) represents a potential biomarker of photoreceptor health on spectral-domain optical coherence tomography (SD-OCT). Because manual quantification of rEZR is laborious and lacks of spatial resolution, automated quantification of the rEZR would be beneficial. The purpose of this study was to evaluate the reliability and reproducibility of an automated rEZR quantification method. Methods The rEZR was acquired using a manual and an automated approach in eyes with age-related macular degeneration (AMD) and healthy controls. The rEZR obtained from both methods was compared and the agreement between the methods and their reproducibility assessed. Results Forty eyes of 40 participants with a mean (± standard deviation) age of 65.2 ± 7.8 years were included. Both the manual and automated method showed that control eyes exhibit a greater rEZR than AMD eyes (P < 0.001). Overall, the limits of agreement between the manual and automated method were -7.5 to 7.3 arbitrary units (AU) and 95% of the data points had a difference in the rEZR between the methods of ±8.2%. An expected perfect reproducibility was observed for the automated method, whereas the manual method had a coefficient of repeatability of 6.3 arbitrary units. Conclusions The automated quantification of rEZR method is reliable and reproducible. Further studies of the rEZR as a novel biomarker for AMD severity and progression are warranted. Translational Relevance Automated quantification of SD-OCT-based rEZR allows for its comprehensive and longitudinal characterization evaluating its relevance as an in vivo biomarker of photoreceptor function and its prognostic value for AMD progression.
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Affiliation(s)
- Sarah Thiele
- Department of Ophthalmology, University of Bonn, Bonn, Germany.,GRADE Reading Center, University of Bonn, Bonn, Germany
| | - Ben Isselmann
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Maximilian Pfau
- Department of Ophthalmology, University of Bonn, Bonn, Germany.,GRADE Reading Center, University of Bonn, Bonn, Germany.,Department of Biomedical Data Science, Stanford University, Stanford, California, USA
| | - Frank G Holz
- Department of Ophthalmology, University of Bonn, Bonn, Germany.,GRADE Reading Center, University of Bonn, Bonn, Germany
| | - Steffen Schmitz-Valckenberg
- Department of Ophthalmology, University of Bonn, Bonn, Germany.,GRADE Reading Center, University of Bonn, Bonn, Germany
| | - Zhichao Wu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Australia
| | - Robyn H Guymer
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Australia
| | - Chi D Luu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Australia
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17
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Ha A, Kim YK, Lee J, Bak E, Han YS, Kim YW, Jeoung JW, Park KH. Interdigitation Zone Change According to Glaucoma-Stage Advancement. Invest Ophthalmol Vis Sci 2020; 61:20. [PMID: 32301971 PMCID: PMC7401448 DOI: 10.1167/iovs.61.4.20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Purpose To compare the macular interdigitation zone (IZ) of normal eyes with eyes showing different normal-tension glaucoma (NTG) stages. Methods Forty-two normal eyes (age, 56 ± 5.4 years), 45 pre-perimetric eyes (age, 59 ± 6.9 years), 51 mild-to-moderate glaucoma eyes (age, 58 ± 7.2 years; mean deviation [MD], –5.5 ± 3.0 dB), and 50 severe glaucoma eyes (age, 59 ± 6.9 years; MD, –15.1 ± 5.4 dB) were enrolled. All of the subjects underwent high-resolution spectral-domain optical coherence tomography (SD-OCT) to obtain 19 horizontal and 19 vertical macular B-scans 9 mm in length. The en face image of the scan area was divided into 589 rectangular boxes (side length of 375 µm). The IZ locations were marked on the corresponding image boxes. The IZ area was then quantified according to the number of boxes showing IZs among the 589 total boxes. Results The IZ area in the severe glaucoma eyes was significantly smaller than in the mild-to-moderate glaucoma eyes (28.99 ± 7.88 mm2 vs. 40.79 ± 7.46 mm2; P < 0.001), was smaller in the mild-to-moderate glaucoma eyes than in the pre-perimetric glaucoma eyes (40.79 ± 7.46 mm2 vs. 49.92 ± 8.10 mm2; P < 0.001), and was smaller still in the pre-perimetric glaucoma eyes than in the normal eyes (49.92 ± 8.10 mm2 vs. 56.85 ± 7.94 mm2; P < 0.001). In the 146 NTG eyes, a statistically significant correlation was found between IZ area and MD (r = 0.64; P < 0.001). Conclusions SD-OCT revealed a reduction in IZ area in NTG eyes, and the extent of the reduction was positively associated with glaucoma severity. These findings suggest, though tentatively, that changes in the outer retinal layer can occur in the course of glaucoma progression.
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18
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Zhong Y, Mohan K, Liu J, Al-Attar A, Lin P, Flight RM, Sun Q, Warmoes MO, Deshpande RR, Liu H, Jung KS, Mitov MI, Lin N, Butterfield DA, Lu S, Liu J, Moseley HNB, Fan TWM, Kleinman ME, Wang QJ. Loss of CLN3, the gene mutated in juvenile neuronal ceroid lipofuscinosis, leads to metabolic impairment and autophagy induction in retinal pigment epithelium. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165883. [PMID: 32592935 DOI: 10.1016/j.bbadis.2020.165883] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 06/08/2020] [Accepted: 06/16/2020] [Indexed: 12/13/2022]
Abstract
Juvenile neuronal ceroid lipofuscinosis (JNCL, aka. juvenile Batten disease or CLN3 disease) is a lysosomal storage disease characterized by progressive blindness, seizures, cognitive and motor failures, and premature death. JNCL is caused by mutations in the Ceroid Lipofuscinosis, Neuronal 3 (CLN3) gene, whose function is unclear. Although traditionally considered a neurodegenerative disease, CLN3 disease displays eye-specific effects: Vision loss not only is often one of the earliest symptoms of JNCL, but also has been reported in non-syndromic CLN3 disease. Here we described the roles of CLN3 protein in maintaining healthy retinal pigment epithelium (RPE) and normal vision. Using electroretinogram, fundoscopy and microscopy, we showed impaired visual function, retinal autofluorescent lesions, and RPE disintegration and metaplasia/hyperplasia in a Cln3 ~ 1 kb-deletion mouse model [1] on C57BL/6J background. Utilizing a combination of biochemical analyses, RNA-Seq, Seahorse XF bioenergetic analysis, and Stable Isotope Resolved Metabolomics (SIRM), we further demonstrated that loss of CLN3 increased autophagic flux, suppressed mTORC1 and Akt activities, enhanced AMPK activity, and up-regulated gene expression of the autophagy-lysosomal system in RPE-1 cells, suggesting autophagy induction. This CLN3 deficiency induced autophagy induction coincided with decreased mitochondrial oxygen consumption, glycolysis, the tricarboxylic acid (TCA) cycle, and ATP production. We also reported for the first time that loss of CLN3 led to glycogen accumulation despite of impaired glycogen synthesis. Our comprehensive analyses shed light on how loss of CLN3 affect autophagy and metabolism. This work suggests possible links among metabolic impairment, autophagy induction and lysosomal storage, as well as between RPE atrophy/degeneration and vision loss in JNCL.
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Affiliation(s)
- Yu Zhong
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, United States
| | - Kabhilan Mohan
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY, United States
| | - Jinpeng Liu
- Markey Cancer Center, University of Kentucky, Lexington, KY, United States
| | - Ahmad Al-Attar
- Center for Environmental and Systems Biochemistry, University of Kentucky, Lexington, KY, United States
| | - Penghui Lin
- Center for Environmental and Systems Biochemistry, University of Kentucky, Lexington, KY, United States
| | - Robert M Flight
- Markey Cancer Center, University of Kentucky, Lexington, KY, United States; Center for Environmental and Systems Biochemistry, University of Kentucky, Lexington, KY, United States
| | - Qiushi Sun
- Center for Environmental and Systems Biochemistry, University of Kentucky, Lexington, KY, United States
| | - Marc O Warmoes
- Center for Environmental and Systems Biochemistry, University of Kentucky, Lexington, KY, United States
| | - Rahul R Deshpande
- Center for Environmental and Systems Biochemistry, University of Kentucky, Lexington, KY, United States
| | - Huijuan Liu
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, United States
| | - Kyung Sik Jung
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY, United States
| | - Mihail I Mitov
- Markey Cancer Center, University of Kentucky, Lexington, KY, United States
| | | | - D Allan Butterfield
- Markey Cancer Center, University of Kentucky, Lexington, KY, United States; Department of Chemistry, University of Kentucky, Lexington, KY, United States
| | - Shuyan Lu
- Pfizer Inc., San Diego, CA, United States
| | - Jinze Liu
- Markey Cancer Center, University of Kentucky, Lexington, KY, United States; Department of Computer Science, University of Kentucky, Lexington, KY, United States; Institute for Biomedical Informatics, University of Kentucky, Lexington, KY, United States
| | - Hunter N B Moseley
- Markey Cancer Center, University of Kentucky, Lexington, KY, United States; Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, United States; Institute for Biomedical Informatics, University of Kentucky, Lexington, KY, United States
| | - Teresa W M Fan
- Markey Cancer Center, University of Kentucky, Lexington, KY, United States; Center for Environmental and Systems Biochemistry, University of Kentucky, Lexington, KY, United States; Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, KY, United States
| | - Mark E Kleinman
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY, United States
| | - Qing Jun Wang
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY, United States; Markey Cancer Center, University of Kentucky, Lexington, KY, United States.
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19
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Automated Quantification of Macular Ellipsoid Zone Intensity in Glaucoma Patients: the Method and its Comparison with Manual Quantification. Sci Rep 2019; 9:19771. [PMID: 31875050 PMCID: PMC6930206 DOI: 10.1038/s41598-019-56337-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 12/05/2019] [Indexed: 11/08/2022] Open
Abstract
The macular ellipsoid zone intensity (mEZi) is a known marker of disease severity in a number of diverse ocular diseases. The purpose of this study was to establish an automated method (AM) for mEZi quantification and to compare the method's performance with that of a manual method (MM) for glaucoma patients and healthy controls. Seventy-one (71) mild-to-moderate glaucoma patients, 71 severe-glaucoma patients, and 51 controls were enrolled. Both calibration (n = 160) and validation (n = 33) image sets were compiled. The correlation of AM to MM quantification was assessed by Deming regression for the calibration set, and a compensation formula was generated. Then, for each image in the validation set, the compensated AM quantification was compared with the mean of five repetitive MM quantifications. The AM quantification of the calibration set was found to be linearly correlated with MM in the normal-to-severe-stage glaucoma patients (R2 = 0.914). The validation set's compensated AM quantification produced R2 = 0.991, and the relationship between the 2 quantifications was AM = 1.004(MM) + 0.139. In the validation set, the compensated AM quantification fell within MM quantification's 95% confidence interval in 96.9% of the images. An AM for mEZi quantification was calibrated and validated relative to MM quantification for both glaucoma patients and healthy controls.
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20
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Singh G, Sridharan D, Khan M, Seshagiri PB. Mouse embryonic stem cell-derived cardiomyocytes cease to beat following exposure to monochromatic light: association with increased ROS and loss of calcium transients. Am J Physiol Cell Physiol 2019; 317:C725-C736. [PMID: 31314584 DOI: 10.1152/ajpcell.00188.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We earlier established the mouse embryonic stem (ES) cell "GS-2" line expressing enhanced green fluorescent protein (EGFP) and have been routinely using it to understand the molecular regulation of differentiation into cardiomyocytes. During such studies, we made a serendipitous discovery that functional cardiomyocytes derived from ES cells stopped beating when exposed to blue light. We observed a gradual cessation of contractility within a few minutes, regardless of wavelength (nm) ranges tested: blue (~420-495), green (~510-575), and red (~600-700), with green light manifesting the strongest impact. Following shifting of cultures back into the incubator (darkness), cardiac clusters regained beatings within a few hours. The observed light-induced contractility-inhibition effect was intrinsic to cardiomyocytes and not due to interference from other cell types. Also, this was not influenced by any physicochemical parameters or intracellular EGFP expression. Interestingly, the light-induced cardiomyocyte contractility inhibition was accompanied by increased intracellular reactive oxygen species (ROS), which could be abolished in the presence of N-acetylcysteine (ROS quencher). Besides, the increased intracardiomyocyte ROS levels were incidental to the inhibition of calcium transients and suppression of mitochondrial activity, both being essential for sarcomere function. To the best of our knowledge, ours is the first report to demonstrate the monochromatic light-mediated inhibition of contractions of cardiomyocytes with no apparent loss of cell viability and contractility. Our findings have implications in cardiac cell biology context in terms of 1) mechanistic insights into light impact on cardiomyocyte contraction, 2) potential use in laser beam-guided (cardiac) microsurgery, photo-optics-dependent medical diagnostics, 3) transient cessation of hearts during coronary artery bypass grafting, and 4) functional preservation of hearts for transplantation.
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Affiliation(s)
- Gurbind Singh
- Centre for Stem Cell Research, Christian Medical College Campus, Bagayam, Vellore, India
| | - Divya Sridharan
- Department of Molecular Reproduction, Development, and Genetics, Indian Institute of Science, Bangalore, India
| | - Mahmood Khan
- Department of Emergency Medicine, Wexner Medical Centre, Ohio State University, Columbus, Ohio
| | - Polani B Seshagiri
- Department of Molecular Reproduction, Development, and Genetics, Indian Institute of Science, Bangalore, India
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Burkemper B, Torres M, Jiang X, McKean-Cowdin R, Varma R. Factors Associated with Visual Impairment in Chinese American Adults: The Chinese American Eye Study. Ophthalmic Epidemiol 2019; 26:329-335. [PMID: 31146615 DOI: 10.1080/09286586.2019.1622737] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Purpose: To assess associations between multiple factors comprising a conceptual model of visual impairment (VI) in a population of Chinese Americans (CAs), and identify independent VI risk factors. Methods: A population-based study of 4582 CAs aged 50 years and older residing in Monterey Park, California. A comprehensive eye examination was performed. VI was defined as best-corrected visual acuity <20/40 (US definition) in the better-seeing eye. Results: Of five independent risk factors identified, age and self-reported history of ocular disease were most strongly associated with VI. Participants 70 years and older were 10.0 times as likely to have VI compared to those in their 50s (95% confidence interval (CI) 4.0-25.0), while those with a history of ocular disease were 4.2 times as likely to have VI (95% CI 2.2-7.8). Additional risk factors included low education (OR 2.8, 95% CI 1.7-4.8), low acculturation (OR 5.9, 95% CI 2.0-17.3) and self-reported history of diabetes (OR 2.0, 95% CI 1.2-3.2). A comparison to data previously described from the Los Angeles Latino Eye Study indicated that four of the factors that predict VI risk in CAs also represent clinically relevant risk factors for VI in Latinos. Conclusions: Screening programs for individuals with advanced age and a history of ocular disease have the potential to reduce the burden of VI in CAs, as do educational programs for those with fewer years in school, a history of diabetes, and low acculturation.
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Affiliation(s)
- Bruce Burkemper
- Southern California Eye Institute, CHA Hollywood Presbyterian Medical Center , Los Angeles , CA , USA
| | - Mina Torres
- Southern California Eye Institute, CHA Hollywood Presbyterian Medical Center , Los Angeles , CA , USA
| | - Xuejuan Jiang
- Departments of Ophthalmology and Preventive Medicine, Keck School of Medicine of the University of Southern California , Los Angeles , CA , USA
| | - Roberta McKean-Cowdin
- Departments of Ophthalmology and Preventive Medicine, Keck School of Medicine of the University of Southern California , Los Angeles , CA , USA
| | - Rohit Varma
- Southern California Eye Institute, CHA Hollywood Presbyterian Medical Center , Los Angeles , CA , USA
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22
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Du J, An J, Linton JD, Wang Y, Hurley JB. How Excessive cGMP Impacts Metabolic Proteins in Retinas at the Onset of Degeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1074:289-295. [PMID: 29721955 DOI: 10.1007/978-3-319-75402-4_35] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Aryl-hydrocarbon receptor interacting protein-like 1 (AIPL1) is essential to stabilize cGMP phosphodiesterase 6 (PDE6) in rod photoreceptors. Mutation of AIPL1 leads to loss of PDE6, accumulation of intracellular cGMP, and rapid degeneration of rods. To understand the metabolic basis for the photoreceptor degeneration caused by excessive cGMP, we performed proteomics and phosphoproteomics analyses on retinas from AIPL1-/- mice at the onset of rod cell death. AIPL1-/- retinas have about 18 times less than normal PDE6a and no detectable PDE6b. We identified twelve other proteins and thirty-nine phosphorylated proteins related to cell metabolism that are significantly altered preceding the massive degeneration of rods. They include transporters, kinases, phosphatases, transferases, and proteins involved in mitochondrial bioenergetics and metabolism of glucose, lipids, amino acids, nucleotides, and RNA. In AIPLI-/- retinas mTOR and proteins involved in mitochondrial energy production and lipid synthesis are more dephosphorylated, but glycolysis proteins and proteins involved in leucine catabolism are more phosphorylated than in normal retinas. Our findings indicate that elevating cGMP rewires cellular metabolism prior to photoreceptor degeneration and that targeting metabolism may be a productive strategy to prevent or slow retinal degeneration.
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Affiliation(s)
- Jianhai Du
- Departments of Ophthalmology, and Biochemistry, West Virginia University, Morgantown, WV, USA
- Department of Ophthalmology, University of Washington, Seattle, WA, USA
| | - Jie An
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - Jonathan D Linton
- Department of Ophthalmology, University of Washington, Seattle, WA, USA
| | - Yekai Wang
- Departments of Ophthalmology, and Biochemistry, West Virginia University, Morgantown, WV, USA
| | - James B Hurley
- Department of Ophthalmology, University of Washington, Seattle, WA, USA.
- Department of Biochemistry, University of Washington, Seattle, WA, USA.
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Loss of MPC1 reprograms retinal metabolism to impair visual function. Proc Natl Acad Sci U S A 2019; 116:3530-3535. [PMID: 30808746 DOI: 10.1073/pnas.1812941116] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Glucose metabolism in vertebrate retinas is dominated by aerobic glycolysis (the "Warburg Effect"), which allows only a small fraction of glucose-derived pyruvate to enter mitochondria. Here, we report evidence that the small fraction of pyruvate in photoreceptors that does get oxidized by their mitochondria is required for visual function, photoreceptor structure and viability, normal neuron-glial interaction, and homeostasis of retinal metabolism. The mitochondrial pyruvate carrier (MPC) links glycolysis and mitochondrial metabolism. Retina-specific deletion of MPC1 results in progressive retinal degeneration and decline of visual function in both rod and cone photoreceptors. Using targeted-metabolomics and 13C tracers, we found that MPC1 is required for cytosolic reducing power maintenance, glutamine/glutamate metabolism, and flexibility in fuel utilization.
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24
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Deal SL, Yamamoto S. Unraveling Novel Mechanisms of Neurodegeneration Through a Large-Scale Forward Genetic Screen in Drosophila. Front Genet 2019; 9:700. [PMID: 30693015 PMCID: PMC6339878 DOI: 10.3389/fgene.2018.00700] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 12/13/2018] [Indexed: 01/04/2023] Open
Abstract
Neurodegeneration is characterized by progressive loss of neurons. Genetic and environmental factors both contribute to demise of neurons, leading to diverse devastating cognitive and motor disorders, including Alzheimer's and Parkinson's diseases in humans. Over the past few decades, the fruit fly, Drosophila melanogaster, has become an integral tool to understand the molecular, cellular and genetic mechanisms underlying neurodegeneration. Extensive tools and sophisticated technologies allow Drosophila geneticists to identify and study evolutionarily conserved genes that are essential for neural maintenance. In this review, we will focus on a large-scale mosaic forward genetic screen on the fly X-chromosome that led to the identification of a number of essential genes that exhibit neurodegenerative phenotypes when mutated. Most genes identified from this screen are evolutionarily conserved and many have been linked to human diseases with neurological presentations. Systematic electrophysiological and ultrastructural characterization of mutant tissue in the context of the Drosophila visual system, followed by a series of experiments to understand the mechanism of neurodegeneration in each mutant led to the discovery of novel molecular pathways that are required for neuronal integrity. Defects in mitochondrial function, lipid and iron metabolism, protein trafficking and autophagy are recurrent themes, suggesting that insults that eventually lead to neurodegeneration may converge on a set of evolutionarily conserved cellular processes. Insights from these studies have contributed to our understanding of known neurodegenerative diseases such as Leigh syndrome and Friedreich's ataxia and have also led to the identification of new human diseases. By discovering new genes required for neural maintenance in flies and working with clinicians to identify patients with deleterious variants in the orthologous human genes, Drosophila biologists can play an active role in personalized medicine.
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Affiliation(s)
- Samantha L Deal
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, United States
| | - Shinya Yamamoto
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, United States.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States.,Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, United States
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25
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Lehmann M, Knust E, Hebbar S. Drosophila melanogaster: A Valuable Genetic Model Organism to Elucidate the Biology of Retinitis Pigmentosa. Methods Mol Biol 2019; 1834:221-249. [PMID: 30324448 DOI: 10.1007/978-1-4939-8669-9_16] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Retinitis pigmentosa (RP) is a complex inherited disease. It is associated with mutations in a wide variety of genes with many different functions. These mutations impact the integrity of rod photoreceptors and ultimately result in the progressive degeneration of rods and cone photoreceptors in the retina, leading to complete blindness. A hallmark of this disease is the variable degree to which symptoms are manifest in patients. This is indicative of the influence of the environment, and/or of the distinct genetic makeup of the individual.The fruit fly, Drosophila melanogaster, has effectively proven to be a great model system to better understand interconnected genetic networks. Unraveling genetic interactions and thereby different cellular processes is relatively easy because more than a century of research on flies has enabled the creation of sophisticated genetic tools to perturb gene function. A remarkable conservation of disease genes across evolution and the similarity of the general organization of the fly and vertebrate photoreceptor cell had prompted research on fly retinal degeneration. To date six fly models for RP, including RP4, RP11, RP12, RP14, RP25, and RP26, have been established, and have provided useful information on RP disease biology. In this chapter, an outline of approaches and experimental specifications are described to enable utilizing or developing new fly models of RP.
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Affiliation(s)
- Malte Lehmann
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Elisabeth Knust
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
| | - Sarita Hebbar
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
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26
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Marcogliese PC, Shashi V, Spillmann RC, Stong N, Rosenfeld JA, Koenig MK, Martínez-Agosto JA, Herzog M, Chen AH, Dickson PI, Lin HJ, Vera MU, Salamon N, Graham JM, Ortiz D, Infante E, Steyaert W, Dermaut B, Poppe B, Chung HL, Zuo Z, Lee PT, Kanca O, Xia F, Yang Y, Smith EC, Jasien J, Kansagra S, Spiridigliozzi G, El-Dairi M, Lark R, Riley K, Koeberl DD, Golden-Grant K, Yamamoto S, Wangler MF, Mirzaa G, Hemelsoet D, Lee B, Nelson SF, Goldstein DB, Bellen HJ, Pena LDM. IRF2BPL Is Associated with Neurological Phenotypes. Am J Hum Genet 2018; 103:245-260. [PMID: 30057031 PMCID: PMC6081494 DOI: 10.1016/j.ajhg.2018.07.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 07/02/2018] [Indexed: 12/23/2022] Open
Abstract
Interferon regulatory factor 2 binding protein-like (IRF2BPL) encodes a member of the IRF2BP family of transcriptional regulators. Currently the biological function of this gene is obscure, and the gene has not been associated with a Mendelian disease. Here we describe seven individuals who carry damaging heterozygous variants in IRF2BPL and are affected with neurological symptoms. Five individuals who carry IRF2BPL nonsense variants resulting in a premature stop codon display severe neurodevelopmental regression, hypotonia, progressive ataxia, seizures, and a lack of coordination. Two additional individuals, both with missense variants, display global developmental delay and seizures and a relatively milder phenotype than those with nonsense alleles. The IRF2BPL bioinformatics signature based on population genomics is consistent with a gene that is intolerant to variation. We show that the fruit-fly IRF2BPL ortholog, called pits (protein interacting with Ttk69 and Sin3A), is broadly detected, including in the nervous system. Complete loss of pits is lethal early in development, whereas partial knockdown with RNA interference in neurons leads to neurodegeneration, revealing a requirement for this gene in proper neuronal function and maintenance. The identified IRF2BPL nonsense variants behave as severe loss-of-function alleles in this model organism, and ectopic expression of the missense variants leads to a range of phenotypes. Taken together, our results show that IRF2BPL and pits are required in the nervous system in humans and flies, and their loss leads to a range of neurological phenotypes in both species.
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Affiliation(s)
- Paul C Marcogliese
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Vandana Shashi
- Division of Medical Genetics, Department of Pediatrics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Rebecca C Spillmann
- Division of Medical Genetics, Department of Pediatrics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Nicholas Stong
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY 10032, USA
| | - Jill A Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mary Kay Koenig
- Division of Child & Adolescent Neurology, Department of Pediatrics, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Julián A Martínez-Agosto
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Child and Adolescent Psychiatry, Resnick Neuropsychiatric Hospital, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Matthew Herzog
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Agnes H Chen
- Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Patricia I Dickson
- Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Henry J Lin
- Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Moin U Vera
- Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Noriko Salamon
- Department of Radiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - John M Graham
- Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Damara Ortiz
- Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, PA 15224, USA
| | - Elena Infante
- Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, PA 15224, USA
| | - Wouter Steyaert
- Department of Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium
| | - Bart Dermaut
- Department of Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium
| | - Bruce Poppe
- Department of Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium
| | - Hyung-Lok Chung
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zhongyuan Zuo
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Pei-Tseng Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Oguz Kanca
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Fan Xia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yaping Yang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Edward C Smith
- Division of Neurology, Department of Pediatrics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Joan Jasien
- Division of Neurology, Department of Pediatrics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Sujay Kansagra
- Division of Neurology, Department of Pediatrics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Gail Spiridigliozzi
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC 27710, USA
| | - Mays El-Dairi
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Robert Lark
- Department of Orthopedic Surgery, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kacie Riley
- Division of Medical Genetics, Department of Pediatrics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Dwight D Koeberl
- Division of Medical Genetics, Department of Pediatrics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Katie Golden-Grant
- Division of Genetic Medicine, Seattle Children's Hospital, Seattle, WA 98105, USA
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Michael F Wangler
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Ghayda Mirzaa
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98105, USA; Department of Pediatrics, University of Washington, Seattle, WA 98105, USA
| | - Dimitri Hemelsoet
- Department of Neurology, Ghent University Hospital, 9000 Ghent, Belgium
| | - Brendan Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Stanley F Nelson
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - David B Goldstein
- Institute for Genomic Medicine, Columbia University Medical Center, New York, NY 10032, USA
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA.
| | - Loren D M Pena
- Division of Medical Genetics, Department of Pediatrics, Duke University School of Medicine, Durham, NC 27710, USA.
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Ha A, Kim YK, Jeoung JW, Park KH. Ellipsoid Zone Change According to Glaucoma Stage Advancement. Am J Ophthalmol 2018; 192:1-9. [PMID: 29750944 DOI: 10.1016/j.ajo.2018.04.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/24/2018] [Accepted: 04/28/2018] [Indexed: 01/01/2023]
Abstract
PURPOSE To compare retinal photoreceptor ellipsoid zone (EZ) intensity between normal eyes and those with different stages of glaucoma. DESIGN Retrospective cross-sectional study. METHODS The study included 37 normal, 38 preperimetric glaucoma, 39 mild-to-moderate glaucoma (visual field [VF] mean deviation [MD]: -7.7 ± 2.0 dB), and 36 severe glaucoma eyes (VF MD: -17.8 ± 3.2 dB). The subjects underwent high-resolution horizontal and vertical line scans through the fovea by spectral-domain optical coherence tomography (SD-OCT). Image processing software was employed to quantify the intensity of the first and second hyperreflective bands corresponding with the external limiting membrane (ELM) and EZ. In order to account for the brightness variation among scans, the relative EZ intensity as the ratio of the second to first reflective band (EZ/ELM) was determined. RESULTS The relative EZ intensity in severe glaucoma eyes was significantly lower than in mild-to-moderate glaucoma eyes (2.46 ± 0.38 vs 3.15 ± 0.43, P < .001); also, it was lower in mild-to-moderate than in preperimetric glaucoma eyes (3.15 ± 0.43 vs 3.86 ± 0.44, P < .001). However, the comparison between preperimetric glaucoma and normal eyes showed no significant difference (3.86 ± 0.44 vs 4.06 ± 0.40, P = .751). In 75 glaucomatous eyes with VF defect, there was a significant correlation between relative EZ intensity and VF MD (r = 0.83 and P < .001). CONCLUSIONS According to SD-OCT, relative EZ intensity reduction occurs in the mild-to-moderate and severe glaucoma stages. These findings suggest, at least provisionally, that in the course of glaucoma progression, mitochondrial changes in the inner segments of photoreceptors occur. Further investigation is warranted to evaluate the potential clinical significance of EZ intensity reduction in glaucoma.
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Affiliation(s)
- Ahnul Ha
- Department of Medicine, Seoul National University College of Medicine, Seoul, South Korea; and Department of Ophthalmology, Seoul National University Hospital, Seoul, South Korea
| | - Young Kook Kim
- Department of Medicine, Seoul National University College of Medicine, Seoul, South Korea; and Department of Ophthalmology, Seoul National University Hospital, Seoul, South Korea
| | - Jin Wook Jeoung
- Department of Medicine, Seoul National University College of Medicine, Seoul, South Korea; and Department of Ophthalmology, Seoul National University Hospital, Seoul, South Korea
| | - Ki Ho Park
- Department of Medicine, Seoul National University College of Medicine, Seoul, South Korea; and Department of Ophthalmology, Seoul National University Hospital, Seoul, South Korea.
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29
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Singhal N, Jaiswal M. Pathways to neurodegeneration: lessons learnt from unbiased genetic screens in Drosophila. J Genet 2018; 97:773-781. [PMID: 30027908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Neurodegenerative diseases are a complex set of disorders that are known to be caused by environmental as well as genetic factors. In the recent past, mutations in a large number of genes have been identified that are linked to several neurodegenerative diseases. The pathogenic mechanisms in most of these disorders are unknown. Recently, studies of genes that are linked to neurodegeneration in Drosophila, the fruit flies, have contributed significantly to our understanding of mechanisms of neuroprotection and degeneration. In this review, we focus on forward genetic screens in Drosophila that helped in identification of novel genes and pathogenic mechanisms linked to neurodegeneration. We also discuss identification of four novel pathways that contribute to neurodegeneration upon mitochondrial dysfunction.
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Affiliation(s)
- Neha Singhal
- Tata Institute of Fundamental Research Hyderabad, Hyderabad 500 107, India.
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30
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Şentürk M, Bellen HJ. Genetic strategies to tackle neurological diseases in fruit flies. Curr Opin Neurobiol 2018; 50:24-32. [PMID: 29128849 PMCID: PMC5940587 DOI: 10.1016/j.conb.2017.10.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 10/13/2017] [Accepted: 10/17/2017] [Indexed: 10/18/2022]
Abstract
Drosophila melanogaster is a genetic model organism that has contributed to the discovery of numerous genes whose human homologues are associated with diseases. The development of sophisticated genetic tools to manipulate its genome accelerates the discovery of the genetic basis of undiagnosed human diseases and the elucidation of molecular pathogenic events of known and novel diseases. Here, we discuss various approaches used in flies to assess the function of the fly homologues of disease-associated genes. We highlight how systematic and combinatorial approaches based on recently established methods provide us with integrated tool sets that can be applied to the study of neurodevelopmental and neurodegenerative disorders.
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Affiliation(s)
- Mümine Şentürk
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA; Department of Molecular and Human Genetics, BCM, Houston TX 77030, USA; Department of Neuroscience, BCM, Houston TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston TX 77030, USA; Howard Hughes Medical Institute, BCM, Houston, TX 77030, USA.
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31
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Ueda A, Woods S, McElree I, O'Harrow TCDG, Inman C, Thenuwara S, Aftab M, Iyengar A. Two novel forms of ERG oscillation in Drosophila: age and activity dependence. J Neurogenet 2018; 32:118-126. [PMID: 29688104 DOI: 10.1080/01677063.2018.1461866] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Over an animal's lifespan, neuronal circuits and systems often decline in an inherently heterogeneous fashion. To compare the age-dependent progression of changes in visual behavior with alterations in retinal physiology, we examined phototaxis and electroretinograms (ERGs) in a wild-type D. melanogaster strain (Canton-S) across their lifespan. In aged flies (beyond 50% median lifespan), we found a marked decline in phototaxis, while motor coordination was less disrupted, as indicated by relatively stronger negative geotaxis. These aged flies displayed substantially reduced ERG transient amplitudes while the receptor potentials (RP) remained largely intact. Using a repetitive light flash protocol, we serendipitously discovered two forms of activity-dependent oscillation in the ERG waveforms of young flies: 'light-off' and 'light-on' oscillations. After repeated 500 ms light flashes, light-off oscillations appeared during the ERG off-transients (frequency: 50-120 Hz, amplitude: ∼1 mV). Light-on oscillations (100-200 Hz, ∼0.3 mV) were induced by a series of 50 ms flashes, and were evident during the ERG on-transients. Both forms of oscillation were observed in other strains of D. melanogaster (Oregon-R, Berlin), additional Drosophila species (D. funerbris, D. euronotus, D. hydei, D. americana), and were evoked by a variety of light sources. Both light-off and light-on oscillations were distinct from previously described ERG oscillations in the visual mutant rosA in terms of location within the waveform and frequency. However, within rosA mutants, light-off oscillations, but not light-on oscillations could be recruited by the repetitive light flash protocol. Importantly though, we found that both forms of oscillation were rarely observed in aged flies. Although the physiological bases of these oscillations remain to be elucidated, they may provide important clues to age-related changes in neuronal excitability and synaptic transmission.
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Affiliation(s)
- Atsushi Ueda
- a Department of Biology , University of Iowa , Iowa City , IA , USA
| | - Scott Woods
- a Department of Biology , University of Iowa , Iowa City , IA , USA
| | - Ian McElree
- a Department of Biology , University of Iowa , Iowa City , IA , USA
| | | | - Casey Inman
- a Department of Biology , University of Iowa , Iowa City , IA , USA
| | | | - Muhammad Aftab
- a Department of Biology , University of Iowa , Iowa City , IA , USA
| | - Atulya Iyengar
- a Department of Biology , University of Iowa , Iowa City , IA , USA
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Jaiswal M, Haelterman NA, Sandoval H, Xiong B, Donti T, Kalsotra A, Yamamoto S, Cooper TA, Graham BH, Bellen HJ. Correction: Impaired Mitochondrial Energy Production Causes Light-Induced Photoreceptor Degeneration Independent of Oxidative Stress. PLoS Biol 2018; 16:e1002622. [PMID: 29509758 PMCID: PMC5839534 DOI: 10.1371/journal.pbio.1002622] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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33
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Ackerman CM, Weber PK, Xiao T, Thai B, Kuo TJ, Zhang E, Pett-Ridge J, Chang CJ. Multimodal LA-ICP-MS and nanoSIMS imaging enables copper mapping within photoreceptor megamitochondria in a zebrafish model of Menkes disease. Metallomics 2018; 10:474-485. [PMID: 29507920 DOI: 10.1039/c7mt00349h] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Copper is essential for eukaryotic life, and animals must acquire this nutrient through the diet and distribute it to cells and organelles for proper function of biological targets. Indeed, mutations in the central copper exporter ATP7A contribute to a spectrum of diseases, including Menkes disease, with symptoms ranging from neurodegeneration to lax connective tissue. As such, a better understanding of the fundamental impacts of ATP7A mutations on in vivo copper distributions is of relevance to those affected by these diseases. Here we combine metal imaging and optical imaging techniques at a variety of spatial resolutions to identify tissues and structures with altered copper levels in the Calamitygw71 zebrafish model of Menkes disease. Rapid profiling of tissue slices with LA-ICP-MS identified reduced copper levels in the brain, neuroretina, and liver of Menkes fish compared to control specimens. High resolution nanoSIMS imaging of the neuroretina, combined with electron and confocal microscopies, identified the megamitochondria of photoreceptors as loci of copper accumulation in wildtype fish, with lower levels of megamitochondrial copper observed in Calamitygw71 zebrafish. Interestingly, this localized copper decrease does not result in impaired photoreceptor development or altered megamitochondrial morphology, suggesting the prioritization of copper at sufficient levels for maintaining essential mitochondrial functions. Together, these data establish the Calamitygw71 zebrafish as an optically transparent in vivo model for the study of neural copper misregulation, illuminate a role for the ATP7A copper exporter in trafficking copper to the neuroretina, and highlight the utility of combining multiple imaging techniques for studying metals in whole organism settings with spatial resolution.
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Affiliation(s)
- Cheri M Ackerman
- Department of Chemistry, University of California, Berkeley, California, USA.
| | - Peter K Weber
- Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, California, USA.
| | - Tong Xiao
- Department of Chemistry, University of California, Berkeley, California, USA. and Howard Hughes Medical Institute, University of California, Berkeley, California, USA
| | - Bao Thai
- Department of Chemistry, University of California, Berkeley, California, USA.
| | - Tiffani J Kuo
- Department of Chemistry, University of California, Berkeley, California, USA.
| | - Emily Zhang
- Department of Chemistry, University of California, Berkeley, California, USA.
| | - Jennifer Pett-Ridge
- Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, California, USA.
| | - Christopher J Chang
- Department of Chemistry, University of California, Berkeley, California, USA. and Howard Hughes Medical Institute, University of California, Berkeley, California, USA and Department of Molecular and Cellular Biology, University of California, Berkeley, California, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
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Schur RM, Gao S, Yu G, Chen Y, Maeda A, Palczewski K, Lu ZR. New GABA modulators protect photoreceptor cells from light-induced degeneration in mouse models. FASEB J 2018; 32:3289-3300. [PMID: 29401616 DOI: 10.1096/fj.201701250r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
No clinically approved therapies are currently available that prevent the onset of photoreceptor death in retinal degeneration. Signaling between retinal neurons is regulated by the release and uptake of neurotransmitters, wherein GABA is the main inhibitory neurotransmitter. In this work, novel 3-chloropropiophenone derivatives and the clinical anticonvulsants tiagabine and vigabatrin were tested to modulate GABA signaling and protect against light-induced retinal degeneration. Abca4-/-Rdh8-/- mice, an accelerated model of retinal degeneration, were exposed to intense light after prophylactic injections of one of these compounds. Imaging and functional assessments of the retina indicated that these compounds successfully protected photoreceptor cells from degeneration to maintain a full-visual-field response. Furthermore, these compounds demonstrated a strong safety profile in wild-type mice and did not compromise visual function or damage the retina, despite repeated administration. These results indicate that modulating inhibitory GABA signaling can offer prophylactic protection against light-induced retinal degeneration.-Schur, R. M., Gao, S., Yu, G., Chen, Y., Maeda, A., Palczewski, K., Lu, Z.-R. New GABA modulators protect photoreceptor cells from light-induced degeneration in mouse models.
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Affiliation(s)
- Rebecca M Schur
- Case Center for Biomolecular Engineering, Department of Biomedical Engineering, School of Engineering, Case Western Reserve University, Cleveland, Ohio, USA
| | - Songqi Gao
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Guanping Yu
- Case Center for Biomolecular Engineering, Department of Biomedical Engineering, School of Engineering, Case Western Reserve University, Cleveland, Ohio, USA
| | - Yu Chen
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Akiko Maeda
- Department of Ophthalmology and Visual Sciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Krzysztof Palczewski
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Zheng-Rong Lu
- Case Center for Biomolecular Engineering, Department of Biomedical Engineering, School of Engineering, Case Western Reserve University, Cleveland, Ohio, USA
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35
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Liu L, MacKenzie KR, Putluri N, Maletić-Savatić M, Bellen HJ. The Glia-Neuron Lactate Shuttle and Elevated ROS Promote Lipid Synthesis in Neurons and Lipid Droplet Accumulation in Glia via APOE/D. Cell Metab 2017; 26:719-737.e6. [PMID: 28965825 PMCID: PMC5677551 DOI: 10.1016/j.cmet.2017.08.024] [Citation(s) in RCA: 301] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 06/21/2017] [Accepted: 08/30/2017] [Indexed: 01/04/2023]
Abstract
Elevated reactive oxygen species (ROS) induce the formation of lipids in neurons that are transferred to glia, where they form lipid droplets (LDs). We show that glial and neuronal monocarboxylate transporters (MCTs), fatty acid transport proteins (FATPs), and apolipoproteins are critical for glial LD formation. MCTs enable glia to secrete and neurons to absorb lactate, which is converted to pyruvate and acetyl-CoA in neurons. Lactate metabolites provide a substrate for synthesis of fatty acids, which are processed and transferred to glia by FATP and apolipoproteins. In the presence of high ROS, inhibiting lactate transfer or lowering FATP or apolipoprotein levels decreases glial LD accumulation in flies and in primary mouse glial-neuronal cultures. We show that human APOE can substitute for a fly glial apolipoprotein and that APOE4, an Alzheimer's disease susceptibility allele, is impaired in lipid transport and promotes neurodegeneration, providing insights into disease mechanisms.
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Affiliation(s)
- Lucy Liu
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Kevin R MacKenzie
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, TX 77030, USA; Center for Drug Discovery, Baylor College of Medicine, Houston, TX 77030, USA
| | - Nagireddy Putluri
- Department of Molecular and Cellular Biology and Advanced Technology Cor, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mirjana Maletić-Savatić
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX 77030, USA
| | - Hugo J Bellen
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA.
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36
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Nagarkar-Jaiswal S, Manivannan SN, Zuo Z, Bellen HJ. A cell cycle-independent, conditional gene inactivation strategy for differentially tagging wild-type and mutant cells. eLife 2017; 6. [PMID: 28561736 PMCID: PMC5493436 DOI: 10.7554/elife.26420] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 05/25/2017] [Indexed: 12/14/2022] Open
Abstract
Here, we describe a novel method based on intronic MiMIC insertions described in Nagarkar-Jaiswal et al. (2015) to perform conditional gene inactivation in Drosophila. Mosaic analysis in Drosophila cannot be easily performed in post-mitotic cells. We therefore, therefore, developed Flip-Flop, a flippase-dependent in vivo cassette-inversion method that marks wild-type cells with the endogenous EGFP-tagged protein, whereas mutant cells are marked with mCherry upon inversion. We document the ease and usefulness of this strategy in differential tagging of wild-type and mutant cells in mosaics. We use this approach to phenotypically characterize the loss of SNF4Aγ, encoding the γ subunit of the AMP Kinase complex. The Flip-Flop method is efficient and reliable, and permits conditional gene inactivation based on both spatial and temporal cues, in a cell cycle-, and developmental stage-independent fashion, creating a platform for systematic screens of gene function in developing and adult flies with unprecedented detail. DOI:http://dx.doi.org/10.7554/eLife.26420.001 The instructions needed to build and maintain cells in an organism are encoded in their DNA. There are many different cell types, and each type only needs a small portion of the information found in the DNA to do its job. Hence, only some of the instructions, in the form of genes, need to be active or ‘expressed’ in any given cell type. To understand how a gene works, it is necessary to know in which cell the gene is expressed and where in the cell the gene product – normally a protein – is located. Researchers may study a gene by deleting it, which prevents the protein from being made, or by attaching a new instruction into the gene, which generates a fluorescent tag on the protein to determine where and when it is expressed. Until now, it was not possible to selectively inactivate a gene and simultaneously mark both normal cells containing the protein and mutant cells lacking the protein. Based on an existing tagging approach, Nagarkar-Jaiswal et al. have now developed a method in which normal and mutant cells of fruit flies are marked differently. A gene of interest is tagged with a fluorescent marker called green fluorescent protein (or GFP). The same gene is then inactivated in some of the cells, which are tagged with a red marker called mCherry. Nagarkar-Jaiswal et al. compared normal and mutant cells, and were able to determine how long it takes before the mutant cells become abnormal. With this new method, the role of numerous genes in any tissue of adult flies can be reassessed. This will allow to investigate what happens when a protein is removed in specific cells in adult flies. A future goal will be to apply this method to other animals that are more closely related to humans, such as mice, to gain a clearer picture of the role of genes in different cell types and how faulty genes may cause disease. DOI:http://dx.doi.org/10.7554/eLife.26420.002
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Affiliation(s)
| | - Sathiya N Manivannan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Zhongyuan Zuo
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Hugo J Bellen
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States.,Department of Neuroscience, Baylor College of Medicine, Houston, United States.,Program in Developmental Biology, Baylor College of Medicine, Houston, United States.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States
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37
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Yoon WH, Sandoval H, Nagarkar-Jaiswal S, Jaiswal M, Yamamoto S, Haelterman NA, Putluri N, Putluri V, Sreekumar A, Tos T, Aksoy A, Donti T, Graham BH, Ohno M, Nishi E, Hunter J, Muzny DM, Carmichael J, Shen J, Arboleda VA, Nelson SF, Wangler MF, Karaca E, Lupski JR, Bellen HJ. Loss of Nardilysin, a Mitochondrial Co-chaperone for α-Ketoglutarate Dehydrogenase, Promotes mTORC1 Activation and Neurodegeneration. Neuron 2017; 93:115-131. [PMID: 28017472 PMCID: PMC5242142 DOI: 10.1016/j.neuron.2016.11.038] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 08/21/2016] [Accepted: 11/14/2016] [Indexed: 01/01/2023]
Abstract
We previously identified mutations in Nardilysin (dNrd1) in a forward genetic screen designed to isolate genes whose loss causes neurodegeneration in Drosophila photoreceptor neurons. Here we show that NRD1 is localized to mitochondria, where it recruits mitochondrial chaperones and assists in the folding of α-ketoglutarate dehydrogenase (OGDH), a rate-limiting enzyme in the Krebs cycle. Loss of Nrd1 or Ogdh leads to an increase in α-ketoglutarate, a substrate for OGDH, which in turn leads to mTORC1 activation and a subsequent reduction in autophagy. Inhibition of mTOR activity by rapamycin or partially restoring autophagy delays neurodegeneration in dNrd1 mutant flies. In summary, this study reveals a novel role for NRD1 as a mitochondrial co-chaperone for OGDH and provides a mechanistic link between mitochondrial metabolic dysfunction, mTORC1 signaling, and impaired autophagy in neurodegeneration.
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Affiliation(s)
- Wan Hee Yoon
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hector Sandoval
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Sonal Nagarkar-Jaiswal
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Manish Jaiswal
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Nele A Haelterman
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Nagireddy Putluri
- Department of Molecular and Cellular Biology and Advanced Technology Core, Baylor College of Medicine, Houston, TX 77030, USA
| | - Vasanta Putluri
- Department of Molecular and Cellular Biology and Advanced Technology Core, Baylor College of Medicine, Houston, TX 77030, USA
| | - Arun Sreekumar
- Department of Molecular and Cellular Biology and Advanced Technology Core, Baylor College of Medicine, Houston, TX 77030, USA
| | - Tulay Tos
- Department of Medical Genetics, Dr. Sami Ulus Research and Training Hospital of Women's and Children's Health and Diseases, Ankara 06080, Turkey
| | - Ayse Aksoy
- Department of Child Neurology, Dr. Sami Ulus Research and Training Hospital of Women's and Children's Health and Diseases, Ankara 06080, Turkey
| | - Taraka Donti
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Brett H Graham
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mikiko Ohno
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan, Baylor College of Medicine, Houston, TX 77030, USA
| | - Eiichiro Nishi
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jill Hunter
- Department of Pediatric Radiology, Texas Children's Hospital and Department of Radiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Donna M Muzny
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jason Carmichael
- Medical Genetics and Metabolism, Valley Children's Hospital, Madera, CA 93636, USA
| | - Joseph Shen
- Medical Genetics and Metabolism, Valley Children's Hospital, Madera, CA 93636, USA
| | - Valerie A Arboleda
- Departments of Human Genetics and Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Stanley F Nelson
- Departments of Human Genetics and Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Michael F Wangler
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Ender Karaca
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA; Department of Pediatrics, Texas Children's Hospital, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hugo J Bellen
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA.
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38
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Chen K, Lin G, Haelterman NA, Ho TSY, Li T, Li Z, Duraine L, Graham BH, Jaiswal M, Yamamoto S, Rasband MN, Bellen HJ. Loss of Frataxin induces iron toxicity, sphingolipid synthesis, and Pdk1/Mef2 activation, leading to neurodegeneration. eLife 2016; 5:e16043. [PMID: 27343351 PMCID: PMC4956409 DOI: 10.7554/elife.16043] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 06/24/2016] [Indexed: 12/22/2022] Open
Abstract
Mutations in Frataxin (FXN) cause Friedreich's ataxia (FRDA), a recessive neurodegenerative disorder. Previous studies have proposed that loss of FXN causes mitochondrial dysfunction, which triggers elevated reactive oxygen species (ROS) and leads to the demise of neurons. Here we describe a ROS independent mechanism that contributes to neurodegeneration in fly FXN mutants. We show that loss of frataxin homolog (fh) in Drosophila leads to iron toxicity, which in turn induces sphingolipid synthesis and ectopically activates 3-phosphoinositide dependent protein kinase-1 (Pdk1) and myocyte enhancer factor-2 (Mef2). Dampening iron toxicity, inhibiting sphingolipid synthesis by Myriocin, or reducing Pdk1 or Mef2 levels, all effectively suppress neurodegeneration in fh mutants. Moreover, increasing dihydrosphingosine activates Mef2 activity through PDK1 in mammalian neuronal cell line suggesting that the mechanisms are evolutionarily conserved. Our results indicate that an iron/sphingolipid/Pdk1/Mef2 pathway may play a role in FRDA.
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Affiliation(s)
- Kuchuan Chen
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Guang Lin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Nele A Haelterman
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Tammy Szu-Yu Ho
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
| | - Tongchao Li
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Zhihong Li
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Lita Duraine
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
| | - Brett H Graham
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Manish Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
| | - Shinya Yamamoto
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, United States
| | - Matthew N Rasband
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, United States
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39
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David-Morrison G, Xu Z, Rui YN, Charng WL, Jaiswal M, Yamamoto S, Xiong B, Zhang K, Sandoval H, Duraine L, Zuo Z, Zhang S, Bellen HJ. WAC Regulates mTOR Activity by Acting as an Adaptor for the TTT and Pontin/Reptin Complexes. Dev Cell 2016; 36:139-51. [PMID: 26812014 DOI: 10.1016/j.devcel.2015.12.019] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 10/16/2015] [Accepted: 12/18/2015] [Indexed: 01/09/2023]
Abstract
The ability to sense energy status is crucial in the regulation of metabolism via the mechanistic Target of Rapamycin Complex 1 (mTORC1). The assembly of the TTT-Pontin/Reptin complex is responsive to changes in energy status. Under energy-sufficient conditions, the TTT-Pontin/Reptin complex promotes mTORC1 dimerization and mTORC1-Rag interaction, which are critical for mTORC1 activation. We show that WAC is a regulator of energy-mediated mTORC1 activity. In a Drosophila screen designed to isolate mutations that cause neuronal dysfunction, we identified wacky, the homolog of WAC. Loss of Wacky leads to neurodegeneration, defective mTOR activity, and increased autophagy. Wacky and WAC have conserved physical interactions with mTOR and its regulators, including Pontin and Reptin, which bind to the TTT complex to regulate energy-dependent activation of mTORC1. WAC promotes the interaction between TTT and Pontin/Reptin in an energy-dependent manner, thereby promoting mTORC1 activity by facilitating mTORC1 dimerization and mTORC1-Rag interaction.
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Affiliation(s)
| | - Zhen Xu
- The Brown Foundation Institute of Molecular Medicine, The University of Texas Medical School at Houston, Houston, TX 77030, USA
| | - Yan-Ning Rui
- The Brown Foundation Institute of Molecular Medicine, The University of Texas Medical School at Houston, Houston, TX 77030, USA
| | - Wu-Lin Charng
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Manish Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - Shinya Yamamoto
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Bo Xiong
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ke Zhang
- Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hector Sandoval
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lita Duraine
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zhongyuan Zuo
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Sheng Zhang
- The Brown Foundation Institute of Molecular Medicine, The University of Texas Medical School at Houston, Houston, TX 77030, USA; Department of Neurobiology and Anatomy, The University of Texas Medical School at Houston, Houston, TX 77030, USA; Programs in Human and Molecular Genetics and Neuroscience, The Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX 77030, USA.
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, TX 77030, USA.
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