1
|
Wei Z, Hao C, Radeen KR, Srinivasagan R, Chen JK, Sharma S, McGee-Lawrence ME, Hamrick MW, Monnier VM, Fan X. Prevention of age-related truncation of γ-glutamylcysteine ligase catalytic subunit (GCLC) delays cataract formation. SCIENCE ADVANCES 2024; 10:eadl1088. [PMID: 38669339 PMCID: PMC11051666 DOI: 10.1126/sciadv.adl1088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 03/22/2024] [Indexed: 04/28/2024]
Abstract
A sharp drop in lenticular glutathione (GSH) plays a pivotal role in age-related cataract (ARC) formation. Despite recognizing GSH's importance in lens defense for decades, its decline with age remains puzzling. Our recent study revealed an age-related truncation affecting the essential GSH biosynthesis enzyme, the γ-glutamylcysteine ligase catalytic subunit (GCLC), at aspartate residue 499. Intriguingly, these truncated GCLC fragments compete with full-length GCLC in forming a heterocomplex with the modifier subunit (GCLM) but exhibit markedly reduced enzymatic activity. Crucially, using an aspartate-to-glutamate mutation knock-in (D499E-KI) mouse model that blocks GCLC truncation, we observed a notable delay in ARC formation compared to WT mice: Nearly 50% of D499E-KI mice remained cataract-free versus ~20% of the WT mice at their age of 20 months. Our findings concerning age-related GCLC truncation might be the key to understanding the profound reduction in lens GSH with age. By halting GCLC truncation, we can rejuvenate lens GSH levels and considerably postpone cataract onset.
Collapse
Affiliation(s)
- Zongbo Wei
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Caili Hao
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Kazi Rafsan Radeen
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Ramkumar Srinivasagan
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Jian-Kang Chen
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Shruti Sharma
- Department of Ophthalmology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Meghan E. McGee-Lawrence
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Mark W. Hamrick
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Vincent M. Monnier
- Department of Pathology and Biochemistry, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Xingjun Fan
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| |
Collapse
|
2
|
Duché G, Sanderson JM. The Chemical Reactivity of Membrane Lipids. Chem Rev 2024; 124:3284-3330. [PMID: 38498932 PMCID: PMC10979411 DOI: 10.1021/acs.chemrev.3c00608] [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: 09/04/2023] [Revised: 02/27/2024] [Accepted: 02/28/2024] [Indexed: 03/20/2024]
Abstract
It is well-known that aqueous dispersions of phospholipids spontaneously assemble into bilayer structures. These structures have numerous applications across chemistry and materials science and form the fundamental structural unit of the biological membrane. The particular environment of the lipid bilayer, with a water-poor low dielectric core surrounded by a more polar and better hydrated interfacial region, gives the membrane particular biophysical and physicochemical properties and presents a unique environment for chemical reactions to occur. Many different types of molecule spanning a range of sizes, from dissolved gases through small organics to proteins, are able to interact with membranes and promote chemical changes to lipids that subsequently affect the physicochemical properties of the bilayer. This Review describes the chemical reactivity exhibited by lipids in their membrane form, with an emphasis on conditions where the lipids are well hydrated in the form of bilayers. Key topics include the following: lytic reactions of glyceryl esters, including hydrolysis, aminolysis, and transesterification; oxidation reactions of alkenes in unsaturated fatty acids and sterols, including autoxidation and oxidation by singlet oxygen; reactivity of headgroups, particularly with reactive carbonyl species; and E/Z isomerization of alkenes. The consequences of reactivity for biological activity and biophysical properties are also discussed.
Collapse
Affiliation(s)
- Genevieve Duché
- Génie
Enzimatique et Cellulaire, Université
Technologique de Compiègne, Compiègne 60200, France
| | - John M Sanderson
- Chemistry
Department, Durham University, Durham DH1 3LE, United Kingdom
| |
Collapse
|
3
|
Overly KE, Shervette VR. Caribbean deepwater snappers: Application of the bomb radiocarbon age estimation validation in understanding aspects of ecology and life history. PLoS One 2023; 18:e0295650. [PMID: 38150486 PMCID: PMC10752517 DOI: 10.1371/journal.pone.0295650] [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: 04/14/2023] [Accepted: 11/21/2023] [Indexed: 12/29/2023] Open
Abstract
Reef fishes have been utilized as food fish throughout the U.S. Caribbean and Gulf of Mexico waters for centuries, with increasing fishing effort in recent decades. As a result, many species have experienced declines in landings, including deepwater snappers such as queen snapper Etelis oculatus and blackfin snapper Lutjanus buccanella. However, little to no peer-reviewed published research exists on basic life history parameters for either species. Confirming the accuracy of an age estimation method for a fish species is essential for ensuring sustainable fisheries management. This is because in the assessment of fisheries species population age-based parameters, including longevity, age at sexual maturity, growth rate, mortality, age-specific reproductive output, and lifetime reproductive output, are important in understanding overall life history strategies of managed stocks. The past stock assessment on U.S. Caribbean queen snapper utilized an estimated longevity of 8 y, derived from length frequencies for fish from St. Lucia. Blackfin snapper has an estimated longevity of 27 y based on a relatively small study from offshore waters of the southeastern U.S. The focus of our investigation was to estimate maximum longevity of two data-poor species in the U.S. Caribbean. The accuracy of ageing methods was tested via bomb radiocarbon age estimation validation and effects of depth on Δ14C in otolith cores and eye lens core values were examined. Results from our work indicate a maximum validated age of 45 y for queen snapper, and 43 y for blackfin snapper. Our findings indicate queen snapper and blackfin snapper are long-lived (> 40 y). The resulting Δ14C comparison between eye lens cores and otolith cores has important implications for the study of age validation, specifically when deepwater species are involved.
Collapse
Affiliation(s)
- Katherine E. Overly
- Technical and Engineering Support Alliance, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Southeast Fisheries Science Center, Panama City, Florida, United States of America
- School of Forest, Fisheries, and Geomatics Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Virginia R. Shervette
- Fish/Fisheries Conservation Lab, University of South Carolina Aiken, Aiken, South Carolina, United States of America
| |
Collapse
|
4
|
Mong MA. Vitamin K and the Visual System-A Narrative Review. Nutrients 2023; 15:nu15081948. [PMID: 37111170 PMCID: PMC10143727 DOI: 10.3390/nu15081948] [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: 02/01/2023] [Revised: 03/30/2023] [Accepted: 03/31/2023] [Indexed: 04/29/2023] Open
Abstract
Vitamin K occupies a unique and often obscured place among its fellow fat-soluble vitamins. Evidence is mounting, however, that vitamin K (VK) may play an important role in the visual system apart from the hepatic carboxylation of hemostatic-related proteins. However, to our knowledge, no review covering the topic has appeared in the medical literature. Recent studies have confirmed that matrix Gla protein (MGP), a vitamin K-dependent protein (VKDP), is essential for the regulation of intraocular pressure in mice. The PREDIMED (Prevención con Dieta Mediterránea) study, a randomized trial involving 5860 adults at risk for cardiovascular disease, demonstrated a 29% reduction in the risk of cataract surgery in participants with the highest tertile of dietary vitamin K1 (PK) intake compared with those with the lowest tertile. However, the specific requirements of the eye and visual system (EVS) for VK, and what might constitute an optimized VK status, is currently unknown and largely unexplored. It is, therefore, the intention of this narrative review to provide an introduction concerning VK and the visual system, review ocular VK biology, and provide some historical context for recent discoveries. Potential opportunities and gaps in current research efforts will be touched upon in the hope of raising awareness and encouraging continued VK-related investigations in this important and highly specialized sensory system.
Collapse
Affiliation(s)
- Michael A Mong
- Department of Ophthalmology, Veteran Affairs North Texas Health Care Medical Center, Dallas, TX 75216, USA
| |
Collapse
|
5
|
Uwineza A, Cummins I, Jarrin M, Kalligeraki AA, Barnard S, Mol M, Degani G, Altomare AA, Aldini G, Schreurs A, Balschun D, Ainsbury EA, Dias IHK, Quinlan RA. Identification and quantification of ionising radiation-induced oxysterol formation in membranes of lens fibre cells. ADVANCES IN REDOX RESEARCH 2023; 7:None. [PMID: 38798747 PMCID: PMC11112148 DOI: 10.1016/j.arres.2022.100057] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 12/06/2022] [Accepted: 12/13/2022] [Indexed: 05/29/2024]
Abstract
Ionising radiation (IR) is a cause of lipid peroxidation, and epidemiological data have revealed a correlation between exposure to IR and the development of eye lens cataracts. Cataracts remain the leading cause of blindness around the world. The plasma membranes of lens fibre cells are one of the most cholesterolrich membranes in the human body, forming lipid rafts and contributing to the biophysical properties of lens fibre plasma membrane. Liquid chromatography followed by mass spectrometry was used to analyse bovine eye lens lipid membrane fractions after exposure to 5 and 50 Gy and eye lenses taken from wholebody 2 Gy-irradiated mice. Although cholesterol levels do not change significantly, IR dose-dependant formation of the oxysterols 7β-hydroxycholesterol, 7-ketocholesterol and 5, 6-epoxycholesterol in bovine lens nucleus membrane extracts was observed. Whole-body X-ray exposure (2 Gy) of 12-week old mice resulted in an increase in 7β-hydroxycholesterol and 7-ketocholesterol in their eye lenses. Their increase regressed over 24 h in the living lens cortex after IR exposure. This study also demonstrated that the IR-induced fold increase in oxysterols was greater in the mouse lens cortex than the nucleus. Further work is required to elucidate the mechanistic link(s) between oxysterols and IR-induced cataract, but these data evidence for the first time that IR exposure of mice results in oxysterol formation in their eye lenses.
Collapse
Affiliation(s)
- Alice Uwineza
- Department of Biosciences, University of Durham, Upper Mountjoy Science Site, South Road, Durham DH1 3LE, United Kingdom
- Biophysical Sciences Institute, University of Durham, South Road, Durham D1 3LE, United Kingdom
| | - Ian Cummins
- Department of Biosciences, University of Durham, Upper Mountjoy Science Site, South Road, Durham DH1 3LE, United Kingdom
| | - Miguel Jarrin
- Department of Biosciences, University of Durham, Upper Mountjoy Science Site, South Road, Durham DH1 3LE, United Kingdom
- Biophysical Sciences Institute, University of Durham, South Road, Durham D1 3LE, United Kingdom
| | - Alexia A. Kalligeraki
- Department of Biosciences, University of Durham, Upper Mountjoy Science Site, South Road, Durham DH1 3LE, United Kingdom
- Biophysical Sciences Institute, University of Durham, South Road, Durham D1 3LE, United Kingdom
| | - Stephen Barnard
- Department of Biosciences, University of Durham, Upper Mountjoy Science Site, South Road, Durham DH1 3LE, United Kingdom
- Biophysical Sciences Institute, University of Durham, South Road, Durham D1 3LE, United Kingdom
- UK Health Security Agency, Cytogenetics and Pathology Group, Centre for Radiation, Chemical and Environmental Hazards Division, Chilton, Oxon OX11 0RQ, Didcot, United Kingdom
| | - Marco Mol
- Department of Pharmaceutical Sciences, Via Mangiagalli 25, Milano 20133, Italy
| | - Genny Degani
- Department of Biosciences, Via Celoria 26, Milano 20133, Italy
| | | | - Giancarlo Aldini
- Department of Pharmaceutical Sciences, Via Mangiagalli 25, Milano 20133, Italy
| | - An Schreurs
- Brain & Cognition, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Detlef Balschun
- Brain & Cognition, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Elizabeth A. Ainsbury
- UK Health Security Agency, Cytogenetics and Pathology Group, Centre for Radiation, Chemical and Environmental Hazards Division, Chilton, Oxon OX11 0RQ, Didcot, United Kingdom
| | - Irundika HK Dias
- Aston Medical School, Aston University, B4 7ET, Birmingham, United Kingdom
| | - Roy A. Quinlan
- Department of Biosciences, University of Durham, Upper Mountjoy Science Site, South Road, Durham DH1 3LE, United Kingdom
- Biophysical Sciences Institute, University of Durham, South Road, Durham D1 3LE, United Kingdom
- Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, United States
| |
Collapse
|
6
|
Muhuri M, Levy DI, Schulz M, McCarty D, Gao G. Durability of transgene expression after rAAV gene therapy. Mol Ther 2022; 30:1364-1380. [PMID: 35283274 PMCID: PMC9077371 DOI: 10.1016/j.ymthe.2022.03.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 01/09/2022] [Accepted: 03/07/2022] [Indexed: 11/19/2022] Open
Abstract
Recombinant adeno-associated virus (rAAV) gene therapy has the potential to transform the lives of patients with certain genetic disorders by increasing or restoring function to affected tissues. Following the initial establishment of transgene expression, it is unknown how long the therapeutic effect will last, although animal and emerging human data show that expression can be maintained for more than 10 years. The durability of therapeutic response is key to long-term treatment success, especially since immune responses to rAAV vectors may prevent re-dosing with the same therapy. This review explores the non-immunological and immunological processes that may limit or improve durability and the strategies that can be used to increase the duration of the therapeutic effect.
Collapse
Affiliation(s)
- Manish Muhuri
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA; Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA, USA
| | | | | | | | - Guangping Gao
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA; Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA, USA; Li Weibo Institute for Rare Diseases Research, University of Massachusetts Medical School, Worcester, MA, USA.
| |
Collapse
|
7
|
Timsina R, Mainali L. Association of Alpha-Crystallin with Fiber Cell Plasma Membrane of the Eye Lens Accompanied by Light Scattering and Cataract Formation. MEMBRANES 2021; 11:447. [PMID: 34203836 PMCID: PMC8232717 DOI: 10.3390/membranes11060447] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 06/11/2021] [Accepted: 06/12/2021] [Indexed: 02/04/2023]
Abstract
α-crystallin is a major protein found in the mammalian eye lens that works as a molecular chaperone by preventing the aggregation of proteins and providing tolerance to stress in the eye lens. These functions of α-crystallin are significant for maintaining lens transparency. However, with age and cataract formation, the concentration of α-crystallin in the eye lens cytoplasm decreases with a corresponding increase in the membrane-bound α-crystallin, accompanied by increased light scattering. The purpose of this review is to summarize previous and recent findings of the role of the: (1) lens membrane components, i.e., the major phospholipids (PLs) and sphingolipids, cholesterol (Chol), cholesterol bilayer domains (CBDs), and the integral membrane proteins aquaporin-0 (AQP0; formally MIP26) and connexins, and (2) α-crystallin mutations and post-translational modifications (PTMs) in the association of α-crystallin to the eye lens's fiber cell plasma membrane, providing thorough insights into a molecular basis of such an association. Furthermore, this review highlights the current knowledge and need for further studies to understand the fundamental molecular processes involved in the association of α-crystallin to the lens membrane, potentially leading to new avenues for preventing cataract formation and progression.
Collapse
Affiliation(s)
- Raju Timsina
- Department of Physics, Boise State University, Boise, ID 83725, USA;
| | - Laxman Mainali
- Department of Physics, Boise State University, Boise, ID 83725, USA;
- Biomolecular Sciences Graduate Program, Boise State University, Boise, ID 83725, USA
| |
Collapse
|
8
|
Lu Q, Zhang Y, Kasetti RB, Gaddipati S, Cvm NK, Borchman D, Li Q. Heterozygous Loss of Yap1 in Mice Causes Progressive Cataracts. Invest Ophthalmol Vis Sci 2021; 61:21. [PMID: 33085740 PMCID: PMC7585397 DOI: 10.1167/iovs.61.12.21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Yap1 encodes an evolutionarily conserved transcriptional coactivator and functions as a down-stream effector of the Hippo signaling pathway that controls tissue size and cell growth. Yap1 contributes to lens epithelial development. However, the effect of Yap1 haplodeficiency on the lens epithelium and its role in the development of cataracts has not been reported. The aim of the current study is to investigate Yap1 function and its regulatory mechanisms in lens epithelial cells (LECs). Methods Lens phenotypes were investigated in Yap1 heterozygous mutant mice by visual observation and histological and biochemical methods. Primary LEC cultures were used to study regulatory molecular mechanism. Results The heterozygous inactivation of Yap1 in mice caused cataracts during adulthood with defective LEC phenotypes. Despite a normal early development of the eye including the lens, the majority of Yap1 heterozygotes developed cataracts in the first six months of age. Cataract was preceded by multiple morphological defects in the lens epithelium, including decreased cell density and abnormal cell junctions. The low LEC density was coincident with reduced LEC proliferation. In addition, expression of the Yap1 target gene Crim1 was reduced in the Yap1+/− LEC, and overexpression of Crim1 restored Yap1+/− LEC cell proliferation in vitro. Conclusions Homozygosity of the Yap1 gene was critical for adequate Crim1 expression needed to maintain the constant proliferation of LEC and to maintain a normal-sized lens. Yap1 haplodeficiency leads to cataracts.
Collapse
Affiliation(s)
- Qingxian Lu
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky, United States
| | - Yingnan Zhang
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky, United States
| | - Ramesh Babu Kasetti
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky, United States
| | - Subhash Gaddipati
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky, United States
| | - Naresh Kumar Cvm
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky, United States
| | - Douglas Borchman
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky, United States
| | - Qiutang Li
- Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, Louisville, Kentucky, United States
| |
Collapse
|
9
|
Borchman D. Lipid conformational order and the etiology of cataract and dry eye. J Lipid Res 2021; 62:100039. [PMID: 32554545 PMCID: PMC7910524 DOI: 10.1194/jlr.tr120000874] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/15/2020] [Indexed: 12/12/2022] Open
Abstract
Lens and tear film lipids are as unique as the systems they reside in. The major lipid of the human lens is dihydrosphingomylein, found in quantity only in the lens. The lens contains a cholesterol to phospholipid molar ratio as high as 10:1, more than anywhere else in the body. Lens lipids contribute to maintaining lens clarity, and alterations in lens lipid composition due to age are likely to contribute to cataract. Lens lipid composition reflects adaptations to the unique characteristics of the lens: no turnover of lens lipids or proteins; the lowest amount of oxygen of any tissue; and contains almost no intracellular organelles. The tear film lipid layer (TFLL) is also unique. The TFLL is a thin (100 nm) layer of lipid on the surface of tears covering the cornea that contributes to tear film stability. The major lipids of the TFLL are wax esters and cholesterol esters that are not found in the lens. The hydrocarbon chains associated with the esters are longer than those found anywhere else in the body (as long as 32 carbons), and many are branched. Changes in the composition and structure of the 30,000 different moieties of TFLL contribute to the instability of tears. The focus of the current review is how spectroscopy has been used to elucidate the relationships between lipid composition, conformational order and function, and the etiology of cataract and dry eye.
Collapse
Affiliation(s)
- Douglas Borchman
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, KY 40202.
| |
Collapse
|
10
|
Lee Y, Overholtzer M. After-Death Functions of Cell Death. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2019; 92:687-694. [PMID: 31866783 PMCID: PMC6913823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cell death can occur through numerous regulated mechanisms, from apoptosis to necrosis, entosis, and others. Each has a distinct mode of regulation and effect on tissue homeostasis. While the elimination of individual cells is typically considered the relevant physiologic endpoint of cell death, in some cases the remnants left behind by death can also function to support tissue homeostasis. Here we discuss specific functions of the end products of cell death, and how "after-death" functions may contribute to the roles of programmed cell death in physiology.
Collapse
Affiliation(s)
- Yongchan Lee
- Cell Biology Program, Sloan Kettering Institute for Cancer Research, New York, NY
| | - Michael Overholtzer
- Cell Biology Program, Sloan Kettering Institute for Cancer Research, New York, NY,Louis V. Gerstner, Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY,BCMB Allied Program, Weill Cornell Medical College, New York, NY,To whom all correspondence should be addressed: Michael Overholtzer, 411 East 67th Street, Rm. RRL-629, New York, NY 10065; Tel: 212-639-6536, Fax: 212-794-4342,
| |
Collapse
|
11
|
Liu P, Edassery SL, Ali L, Thomson BR, Savas JN, Jin J. Long-lived metabolic enzymes in the crystalline lens identified by pulse-labeling of mice and mass spectrometry. eLife 2019; 8:50170. [PMID: 31820737 PMCID: PMC6914337 DOI: 10.7554/elife.50170] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 12/04/2019] [Indexed: 01/29/2023] Open
Abstract
The lenticular fiber cells are comprised of extremely long-lived proteins while still maintaining an active biochemical state. Dysregulation of these activities has been implicated in diseases such as age-related cataracts. However, the lenticular protein dynamics underlying health and disease is unclear. We sought to measure the global protein turnover rates in the eye using nitrogen-15 labeling of mice and mass spectrometry. We measured the 14N/15N-peptide ratios of 248 lens proteins, including Crystallin, Aquaporin, Collagen and enzymes that catalyze glycolysis and oxidation/reduction reactions. Direct comparison of lens cortex versus nucleus revealed little or no 15N-protein contents in most nuclear proteins, while there were a broad range of 14N/15N ratios in cortex proteins. Unexpectedly, like Crystallins, many enzymes with relatively high abundance in nucleus were also exceedingly long-lived. The slow replacement of these enzymes in spite of young age of mice suggests their potential roles in age-related metabolic changes in the lens.
Collapse
Affiliation(s)
- Pan Liu
- Feinberg Cardiovascular and Renal Research Institute, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Seby Louis Edassery
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Laith Ali
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Benjamin R Thomson
- Feinberg Cardiovascular and Renal Research Institute, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Jeffrey N Savas
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Jing Jin
- Feinberg Cardiovascular and Renal Research Institute, Feinberg School of Medicine, Northwestern University, Chicago, United States
| |
Collapse
|
12
|
Why Is Very High Cholesterol Content Beneficial for the Eye Lens but Negative for Other Organs? Nutrients 2019; 11:nu11051083. [PMID: 31096723 PMCID: PMC6566707 DOI: 10.3390/nu11051083] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/08/2019] [Accepted: 05/09/2019] [Indexed: 12/13/2022] Open
Abstract
The plasma membranes of the human lens fiber cell are overloaded with cholesterol that not only saturates the phospholipid bilayer of these membranes but also leads to the formation of pure cholesterol bilayer domains. Cholesterol level increases with age, and for older persons, it exceeds the cholesterol solubility threshold, leading to the formation of cholesterol crystals. All these changes occur in the normal lens without too much compromise to lens transparency. If the cholesterol content in the cell membranes of other organs increases to extent where cholesterol crystals forma, a pathological condition begins. In arterial cells, minute cholesterol crystals activate inflammasomes, induce inflammation, and cause atherosclerosis development. In this review, we will indicate possible factors that distinguish between beneficial and negative cholesterol action, limiting cholesterol actions to those performed through cholesterol in cell membranes and by cholesterol crystals.
Collapse
|
13
|
Distribution of Glycerophospholipids in the Adult Human Lens. Biomolecules 2018; 8:biom8040156. [PMID: 30469542 PMCID: PMC6315977 DOI: 10.3390/biom8040156] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 11/15/2018] [Indexed: 12/04/2022] Open
Abstract
In humans, the age of fibre cells differs across the ocular lens, ranging from those formed before birth in the core of the lens to those formed just prior to death in the outer cortex. The distribution of glycerophospholipids in the adult human lens should reflect this range; however, limited data currently exists to confirm this hypothesis. Accordingly, this study aimed to determine the distribution of glycerophospholipids in adult human lens using mass spectrometry imaging. To achieve this, 20-µm thick slices of two human lenses, aged 51 and 67 were analysed by matrix-assisted laser desorption ionisation imaging mass spectrometry. The data clearly indicate that intact glycerophospholipids such as phosphatidylethanolamine, phosphatidylserine, and phosphatidic acid are mainly present in the outer cortex region, corresponding to the youngest fibre cells, while lyso-phosphatidylethanolamine, likely produced by the degradation of phosphatidylethanolamine, is present in the nucleus (older fibre cells). This study adds further evidence to the relationship between fibre cell age and glycerophospholipid composition.
Collapse
|
14
|
Singh P, Li R. Emerging roles for sphingolipids in cellular aging. Curr Genet 2017; 64:761-767. [PMID: 29260307 DOI: 10.1007/s00294-017-0799-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 12/12/2017] [Accepted: 12/14/2017] [Indexed: 02/07/2023]
Abstract
Aging is a gradual loss of physiological functions as organisms' progress in age. Although aging in multicellular organisms is complex, some fundamental mechanisms and pathways may be shared from the single cellular yeast to human. Budding yeast Saccharomyces cerevisiae has been established model system for aging studies. A yeast cell divides asymmetrically to produce two cells that differ in size and age. The one that is smaller coming from bud is a newborn cell that with a full replicative potential head irrespective of the replicative age of its mother-the larger cell from which the bud grows out before division. The age asymmetry between daughter and mother is thought to be dependent on asymmetric segregation of certain factors such as protein aggregates, extrachromosomal DNA (ERCs) and dysfunctional organelles during successive cell divisions of the yeast replicative lifespan (RLS). It is also thought that certain plasma membrane proteins, in particular multidrug-resistant (MDR) proteins, asymmetrically partition between the mother and the bud based on the age of the polypeptides. Functional decline associated with the molecular aging of those proteins contributes to the fitness decline at advance age. In our recent study, we showed that sphingolipids facilitate the age-dependent segregation of MDRs between daughter and mother cell. In this review, we highlight and discuss the potential mechanisms by which sphingolipids regulate the aging process in yeast and cells of vertebrate animals including human.
Collapse
Affiliation(s)
- Pushpendra Singh
- Laboratory of Adjuvant and Antigen Research, US Military HIV Research Program, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD, 20910, USA. .,US Military HIV Research Program, Henry M. Jackson Foundation for the Advancement of Military Medicine, 6720A Rockledge Drive, Bethesda, MD, 20817, USA.
| | - Rong Li
- Department of Cell Biology, Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.,Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
| |
Collapse
|
15
|
Borchman D, Stimmelmayr R, George JC. Whales, lifespan, phospholipids, and cataracts. J Lipid Res 2017; 58:2289-2298. [PMID: 29038122 DOI: 10.1194/jlr.m079368] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 10/04/2017] [Indexed: 12/18/2022] Open
Abstract
This study addresses the question: why do rats get cataracts at 2 years, dogs at 8 years, and whales do not develop cataracts for 200 years? Whale lens lipid phase transitions were compared with the phase transitions of other species that were recalculated. The major phospholipids of the whale lens were sphingolipids, mostly dihydrosphingomyelins with an average molar cholesterol/phospholipid ratio of 10. There was a linear correlation between the percentage of lens sphingolipid and lens lipid hydrocarbon chain order until about 60% sphingolipid. The percentage of lens sphingolipid correlated with the lens lipid phase transition temperature. The lifespan of the bowhead whale was the longest of the species measured and the percentage of whale lens sphingolipid fit well in the correlation between the percentage of lens sphingolipid and lifespan for many species. In conclusion, bowhead whale lens membranes have a high sphingolipid content that confers resistance to oxidation, allowing these lenses to stay clear relatively longer than many other species. The strong correlation between sphingolipid and lifespan may form a basis for future studies, which are needed because correlations do not infer cause. One could hope that if human lenses could be made to have a lipid composition similar to whales, like the bowhead, humans would not develop age-related cataracts for over 100 years.
Collapse
Affiliation(s)
- Douglas Borchman
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, KY
| | - Raphaela Stimmelmayr
- Department of Wildlife Management, North Slope Borough, Utqiagvik, AK.,Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK
| | - J Craig George
- Department of Wildlife Management, North Slope Borough, Utqiagvik, AK
| |
Collapse
|
16
|
Barnes S, Quinlan RA. Small molecules, both dietary and endogenous, influence the onset of lens cataracts. Exp Eye Res 2016; 156:87-94. [PMID: 27039707 DOI: 10.1016/j.exer.2016.03.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 03/18/2016] [Accepted: 03/28/2016] [Indexed: 12/11/2022]
Abstract
How the lens ages successfully is a lesson in biological adaption and the emergent properties of its complement of cells and proteins. This living tissue contains some of the oldest proteins in our bodies and yet they remain functional for decades, despite exposure to UV light, to reactive oxygen species and all the other hazards to protein function. This remarkable feat is achieved by a shrewd investment in very stable proteins as lens crystallins, by providing a reservoir of ATP-independent protein chaperones unequalled by any other tissue and by an oxidation-resistant environment. In addition, glutathione, a free radical scavenger, is present in mM concentrations and the plasma membranes contain oxidation-resistant sphingolipids what compromises lens function as it ages? In this review, we examine the role of small molecules in the prevention or causation of cataracts, including those associated with diet, metabolic pathways and drug therapy (steroids).
Collapse
Affiliation(s)
- Stephen Barnes
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Roy A Quinlan
- Biophysical Sciences Institute, University of Durham, Durham DH1 3LE, UK; University of Durham, Durham DH1 3LE, UK.
| |
Collapse
|