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MacFarlane ER, Donaldson PJ, Grey AC. UV light and the ocular lens: a review of exposure models and resulting biomolecular changes. FRONTIERS IN OPHTHALMOLOGY 2024; 4:1414483. [PMID: 39301012 PMCID: PMC11410779 DOI: 10.3389/fopht.2024.1414483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Accepted: 08/12/2024] [Indexed: 09/22/2024]
Abstract
UV light is known to cause damage to biomolecules in living tissue. Tissues of the eye that play highly specialised roles in forming our sense of sight are uniquely exposed to light of all wavelengths. While these tissues have evolved protective mechanisms to resist damage from UV wavelengths, prolonged exposure is thought to lead to pathological changes. In the lens, UV light exposure is a risk factor for the development of cataract, which is a condition that is characterised by opacity that impairs its function as a focusing element in the eye. Cataract can affect spatially distinct regions of the lens. Age-related nuclear cataract is the most prevalent form of cataract and is strongly associated with oxidative stress and a decrease in the antioxidant capacity of the central lens region. Since UV light can generate reactive oxygen species to induce oxidative stress, its effects on lens structure, transparency, and biochemistry have been extensively investigated in animal models in order to better understand human cataract aetiology. A review of the different light exposure models and the advances in mechanistic understanding gained from these models is presented.
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Affiliation(s)
- Emily R MacFarlane
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Paul J Donaldson
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Angus C Grey
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
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2
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Li H, Yu Y, Ruan M, Jiao F, Chen H, Gao J, Weng Y, Bao Y. The mechanism for thermal-enhanced chaperone-like activity of α-crystallin against UV irradiation-induced aggregation of γD-crystallin. Biophys J 2022; 121:2233-2250. [PMID: 35619565 DOI: 10.1016/j.bpj.2022.05.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 05/11/2022] [Accepted: 05/20/2022] [Indexed: 11/18/2022] Open
Abstract
Exposure to solar UV irradiation damages γ-crystallin, leading to cataract formation via aggregation. α-Crystallin, as a small heat-shock protein (sHsps), efficiently suppresses this irreversible aggregation by selectively binding the denatured γ-crystallin monomer. In this study, liquid chromatography tandem mass spectrometry (LC-MS) was used to evaluate UV-325 nm irradiation-induced photodamage of human γD-crystallin in the presence of bovine α-crystallin, atomic force microscope (AFM) and dynamic light scattering (DLS) techniques were used to detect the quaternary structure changes of α-crystallin oligomer, and Fourier transform infrared (FTIR) spectroscopy and temperature-jump (T-jump) nanosecond time-resolved IR absorbance difference spectroscopy were used to probe the secondary structure changes of bovine α-crystallin. We find that the thermal-induced subunit dissociation of α-crystallin oligomer involves the breaking of hydrogen bonds at the dimeric interface, leading to three different spectral components at varied temperature regions as resolved from temperature-dependent IR spectra. Under UV-325 nm irradiation, unfolded γD-crystallin binds to the dissociated α-crystallin subunit to form αγ-complex, then follows the reassociation of αγ-complex to the partially dissociated α-crystallin oligomer. This prevents the aggregation of denatured γD-crystallin. The formation of the γD-bound α-crystallin oligomer is further confirmed by AFM and DLS analysis, which reveals an obvious size expansion in the reassociated αγ-oligomers. In addition, UV-325 nm irradiation causes a peptide bond cleavage of γD-crystallin at Ala158 in presence of α-crystallin. Our results suggest a very effective protection mechanism for subunits dissociated from α-crystallin oligomers against UV irradiation-induced aggregation of γD-crystallin, at an expense of a loss of a short C-terminal peptide in γD-crystallin.
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Affiliation(s)
- Hao Li
- Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China; College of Chemical Biology and Biotechnology, Beijing University Shenzhen Graduate School, Shenzhen, China; Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yingying Yu
- Department of Ophthalmology, Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, College of Optometry, Peking University Health Science Center, Beijing, China
| | - Meixia Ruan
- Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Fang Jiao
- Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Hailong Chen
- Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Jiali Gao
- College of Chemical Biology and Biotechnology, Beijing University Shenzhen Graduate School, Shenzhen, China; Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen, China
| | - Yuxiang Weng
- Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.
| | - Yongzhen Bao
- Department of Ophthalmology, Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, College of Optometry, Peking University Health Science Center, Beijing, China.
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3
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Hsueh SS, Lu JH, Wu JW, Lin TH, Wang SSS. Protection of human γD-crystallin protein from ultraviolet C-induced aggregation by ortho-vanillin. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 261:120023. [PMID: 34098480 DOI: 10.1016/j.saa.2021.120023] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 05/20/2021] [Accepted: 05/24/2021] [Indexed: 06/12/2023]
Abstract
Cataract is known as one of the leading causes of vision impairment worldwide. While the detailed mechanism of cataratogenesis remains unclear, cataract is believed to be correlated with the aggregation and/or misfolding of human ocular lens proteins called crystallins. A 173-residue structural protein human γD-crystallin is a major γ-crystallin protein in the human eye lens and associated with the development of juvenile and mature-onset cataracts. This work is aimed at investigating the effect of a small molecule, e.g., ortho-vanillin, on human γD-crystallin aggregation upon exposure to ultraviolet-C irradiation. According to the findings of right-angle light scattering, transmission electron microscopy, and gel electrophoresis, ortho-vanillin was demonstrated to dose-dependently suppress ultraviolet-C-triggered aggregation of human γD-crystallin. Results from the synchronous fluorescence spectroscopy, tryptophan fluorescence quenching, and molecular docking studies revealed the structural change of γD-crystallin induced by the interaction/binding between ortho-vanillin and protein. We believe the outcome from this work may contribute to the development of potential therapeutics for cataract.
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Affiliation(s)
- Shu-Shun Hsueh
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Jian-Hong Lu
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Josephine W Wu
- Department of Optometry, Yuanpei University of Medical Technology, Hsinchu City 30015, Taiwan.
| | - Ta-Hsien Lin
- Basic Research Division, Medical Research Department, Taipei Veterans General Hospital, Taipei 11217, Taiwan; Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan.
| | - Steven S-S Wang
- Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan.
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Muranova LK, Sudnitsyna MV, Gusev NB. αB-Crystallin Phosphorylation: Advances and Problems. BIOCHEMISTRY (MOSCOW) 2018; 83:1196-1206. [DOI: 10.1134/s000629791810005x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Cetinel S, Semenchenko V, Cho JY, Sharaf MG, Damji KF, Unsworth LD, Montemagno C. UV-B induced fibrillization of crystallin protein mixtures. PLoS One 2017; 12:e0177991. [PMID: 28542382 PMCID: PMC5444657 DOI: 10.1371/journal.pone.0177991] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 05/05/2017] [Indexed: 12/28/2022] Open
Abstract
Environmental factors, mainly oxidative stress and exposure to sunlight, induce the oxidation, cross-linking, cleavage, and deamination of crystallin proteins, resulting in their aggregation and, ultimately, cataract formation. Various denaturants have been used to initiate the aggregation of crystallin proteins in vitro. All of these regimens, however, are obviously far from replicating conditions that exist in vivo that lead to cataract formation. In fact, it is our supposition that only UV-B radiation may mimic the observed in vivo cause of crystallin alteration leading to cataract formation. This means of inducing cataract formation may provide the most appropriate in vitro platform for in-depth study of the fundamental cataractous fibril properties and allow for testing of possible treatment strategies. Herein, we showed that cataractous fibrils can be formed using UV-B radiation from α:β:γ crystallin protein mixtures. Characterization of the properties of formed aggregates confirmed the development of amyloid-like fibrils, which are in cross-β-pattern and possibly in anti-parallel β-sheet arrangement. Furthermore, we were also able to confirm that the presence of the molecular chaperone, α-crystallin, was able to inhibit fibril formation, as observed for ‘naturally’ occurring fibrils. Finally, the time-dependent fibrillation profile was found to be similar to the gradual formation of age-related nuclear cataracts. This data provided evidence for the initiation of fibril formation from physiologically relevant crystallin mixtures using UV-B radiation, and that the formed fibrils had several traits similar to that expected from cataracts developing in vivo.
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Affiliation(s)
- Sibel Cetinel
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, Canada
- Ingenuity Lab., University of Alberta, Edmonton, AB, Canada
| | - Valentyna Semenchenko
- National Institute of Nanotechnology (NINT), 11421, Saskatchewan Drive NW, Edmonton, AB, Canada
| | - Jae-Young Cho
- National Institute of Nanotechnology (NINT), 11421, Saskatchewan Drive NW, Edmonton, AB, Canada
| | - Mehdi Ghaffari Sharaf
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, Canada
- Ingenuity Lab., University of Alberta, Edmonton, AB, Canada
| | - Karim F. Damji
- Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, AB, Canada
| | - Larry D. Unsworth
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, Canada
- National Institute of Nanotechnology (NINT), 11421, Saskatchewan Drive NW, Edmonton, AB, Canada
- * E-mail: (CM); (LDU)
| | - Carlo Montemagno
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, Canada
- Ingenuity Lab., University of Alberta, Edmonton, AB, Canada
- * E-mail: (CM); (LDU)
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Panda AK, Nandi SK, Chakraborty A, Nagaraj RH, Biswas A. Differential role of arginine mutations on the structure and functions of α-crystallin. Biochim Biophys Acta Gen Subj 2015; 1860:199-210. [PMID: 26080000 DOI: 10.1016/j.bbagen.2015.06.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 05/22/2015] [Accepted: 06/09/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND α-Crystallin is a major protein of the eye lens in vertebrates. It is composed of two subunits, αA- and αB-crystallin. α-Crystallin is an oligomeric protein having these two subunits in 3:1 ratio. It belongs to small heat shock protein family and exhibits molecular chaperone function, which plays an important role in maintaining the lens transparency. Apart from chaperone function, both subunits also exhibit anti-apoptotic property. Comparison of their primary sequences reveals that αA- and αB-crystallin posses 13 and 14 arginine residues, respectively. Several of them undergo mutations which eventually lead to various eye diseases such as congenital cataract, juvenile cataract, and retinal degeneration. Interestingly, many arginine residues of these subunits are modified during glycation and even some are truncated during aging. All these facts indicate the importance of arginine residues in α-crystallin. SCOPE OF REVIEW In this review, we will emphasize the recent in vitro and in vivo findings related to congenital cataract causing arginine mutations in α-crystallin. MAJOR CONCLUSIONS Congenital cataract causing arginine mutations alters the structure and decreases the chaperone function of α-crystallin. These mutations also affect the lens morphology and phenotypes. Interestingly, non-natural arginine mutations (generated for mimicking the glycation and truncation environment) improve the chaperone function of α-crystallin which may play an important role in maintaining the eye lens transparency during aging. GENERAL SIGNIFICANCE The neutralization of positive charge on the guanidino group of arginine residues is not always detrimental to the functionality of α-crystallin. This article is part of a Special Issue entitled Crystallin Biochemistry in Health and Disease.
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Affiliation(s)
- Alok Kumar Panda
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar, Odisha 751013, India
| | - Sandip Kumar Nandi
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar, Odisha 751013, India
| | - Ayon Chakraborty
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar, Odisha 751013, India
| | - Ram H Nagaraj
- Department of Ophthalmology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Ashis Biswas
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar, Odisha 751013, India.
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Hegde SM, Srivastava K, Tiwary E, Srivastava OP. Molecular mechanism of formation of cortical opacity in CRYAAN101D transgenic mice. Invest Ophthalmol Vis Sci 2014; 55:6398-408. [PMID: 25146988 DOI: 10.1167/iovs.14-14623] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
PURPOSE The CRYAAN101D transgenic mouse model expressing deamidated αA-crystallin (deamidation at N101 position to D) develops cortical cataract at the age of 7 to 9 months. The present study was carried out to explore the molecular mechanism that leads to the development of cortical opacity in CRYAAN101D lenses. METHODS RNA sequence analysis was carried out on 2- and 4-month-old αA-N101D and wild type (WT) lenses. To understand the biologic relevance and function of significantly altered genes, Ingenuity Pathway Analysis (IPA) was done. To elucidate terminal differentiation defects, immunohistochemical, and Western blot analyses were carried out. RESULTS RNA sequence and IPA data suggested that the genes belonging to gene expression, cellular assembly and organization, and cell cycle and apoptosis networks were altered in N101D lenses. In addition, the tight junction signaling and Rho A signaling were among the top three canonical pathways that were affected in N101D mutant. Immunohistochemical analysis identified a series of terminal differentiation defects in N101D lenses, specifically, increased proliferation and decreased differentiation of lens epithelial cells (LEC) and decreased denucleation of lens fiber cells (LFC). The expression of Rho A was reduced in different-aged N101D lenses, and, conversely, Cdc42 and Rac1 expressions were increased in the N101D mutants. Moreover, earlier in development, the expression of major membrane-bound molecular transporter Na,K-ATPase was drastically reduced in N101D lenses. CONCLUSIONS The results suggest that the terminal differentiation defects, specifically, increased proliferation and decreased denucleation are responsible for the development of lens opacity in N101D lenses.
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Affiliation(s)
- Shylaja M Hegde
- Department of Vision Sciences, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Kiran Srivastava
- Department of Vision Sciences, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Ekta Tiwary
- Department of Vision Sciences, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Om P Srivastava
- Department of Vision Sciences, University of Alabama at Birmingham, Birmingham, Alabama, United States
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8
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Wu JWR, Kao CY, Lin LTW, Wen WS, Lai JT, Wang SSS. Human γD-crystallin aggregation induced by ultraviolet C irradiation is suppressed by resveratrol. Biochem Eng J 2013. [DOI: 10.1016/j.bej.2013.03.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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9
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Pajer V, Tiboldi Á, Bae N, Li K, Kang SU, Hopp B, Kolozsvári L, Lubec G, Nógrádi A. The Molecular Background of the Differential UV Absorbance of the Human Lens in the 240-400 nm Range. Photochem Photobiol 2013; 89:856-63. [DOI: 10.1111/php.12063] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 02/07/2013] [Indexed: 11/28/2022]
Affiliation(s)
| | - Ákos Tiboldi
- Department of Pediatrics; Medical University of Vienna; Vienna; Austria
| | - Narkhyun Bae
- Department of Pediatrics; Medical University of Vienna; Vienna; Austria
| | - Kongzhao Li
- Department of Pediatrics; Medical University of Vienna; Vienna; Austria
| | - Sung Ung Kang
- Department of Pediatrics; Medical University of Vienna; Vienna; Austria
| | - Béla Hopp
- Research Group on Laser Physics; Hungarian Academy of Sciences and University of Szeged; Hungary
| | - Lajos Kolozsvári
- Department of Ophthalmology; Albert Szent-Györgyi Clinical Centre; Faculty of Medicine; University of Szeged; Hungary
| | - Gert Lubec
- Department of Pediatrics; Medical University of Vienna; Vienna; Austria
| | - Antal Nógrádi
- Department of Ophthalmology; Albert Szent-Györgyi Clinical Centre; Faculty of Medicine; University of Szeged; Hungary
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The response of human skin commensal bacteria as a reflection of UV radiation: UV-B decreases porphyrin production. PLoS One 2012; 7:e47798. [PMID: 23133525 PMCID: PMC3485044 DOI: 10.1371/journal.pone.0047798] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 09/17/2012] [Indexed: 11/19/2022] Open
Abstract
Recent global radiation fears reflect the urgent need for a new modality that can simply determine if people are in a radiation risk of developing cancer and other illnesses. Ultraviolet (UV) radiation has been thought to be the major risk factor for most skin cancers. Although various biomarkers derived from the responses of human cells have been revealed, detection of these biomarkers is cumbersome, probably requires taking live human tissues, and varies significantly depending on human immune status. Here we hypothesize that the reaction of Propionibacterium acnes (P. acnes), a human resident skin commensal, to UV radiation can serve as early surrogate markers for radiation risk because the bacteria are immediately responsive to radiation. In addition, the bacteria can be readily accessible and exposed to the same field of radiation as human body. To test our hypothesis, P. acnes was exposed to UV-B radiation. The production of porphyrins in P. acnes was significantly reduced with increasing doses of UV-B. The porphyrin reduction can be detected in both P. acnes and human skin bacterial isolates. Exposure of UV-B to P. acnes- inoculated mice led to a significant decrease in porphyrin production in a single colony of P. acnes and simultaneously induced the formation of cyclobutane pyrimidine dimers (CPD) in the epidermal layers of mouse skin. Mass spectrometric analysis via a linear trap quadrupole (LTQ)-Orbitrap XL showed that five peptides including an internal peptide (THLPTGIVVSCQNER) of a peptide chain release factor 2 (RF2) were oxidized by UV-B. Seven peptides including three internal peptides of 60 kDa chaperonin 1 were de-oxidized by UV-B. When compared to UV-B, gamma radiation also decreased the porphyrin production of P. acnes in a dose-dependent manner, but induced a different signature of protein oxidation/de-oxidation. We highlight that uncovering response of skin microbiome to radiation will facilitate the development of pre-symptomatic diagnosis of radiation risk in a battlefield exposure, nuclear accidents, terrorist attacks, or cancer imaging/therapy.
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Kumar PA, Reddy GB. Modulation of alpha-crystallin chaperone activity: a target to prevent or delay cataract? IUBMB Life 2009; 61:485-95. [PMID: 19391162 DOI: 10.1002/iub.176] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Cataract, loss of eye lens transparency, is the leading cause of blindness worldwide. alpha-Crystallin, initially known as one of the major structural proteins of the eye lens, is composed of two homologous subunits alphaA- and alphaB-crystallins. It is convincingly established now that alpha-crystallin functions like a chaperone and plays a decisive role in the maintenance of eye lens transparency. The functional ability of alpha-crystallin subunits is to act in cooperation as molecular chaperones to prevent the cellular aggregation and/or inactivation of client proteins under variety of stress conditions. However, chaperone-like activity of alpha-crystallin could be deteriorated or lost during aging or under certain clinical conditions because of various genetic and environmental factors. This review will focus specifically on relevance of alpha-crystallin chaperone function to lens transparency. In particular, we reviewed the studies that demonstrate the modulation of alpha-crystallin chaperone-like activity and discussed the possibility of chaperone-like activity of alpha-crystallin as a potential target to prevent or delay the cataractogenesis.
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Affiliation(s)
- Pasupulati Anil Kumar
- Biochemistry Division, National Institute of Nutrition, Hyderabad, Andhra Pradesh, India
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12
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Dhir P, Akhtar NJ, Sun TX, Liang JJN. Photooxidized Products of Recombinant αA-Crystallin and W9F Mutant. Photochem Photobiol 2008. [DOI: 10.1111/j.1751-1097.1999.tb03294.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
We undertook an unfolding and refolding study of alpha(L)-crystallin in presence of urea to explore the breakdown and formation of various levels of structure and to find out whether the breakdown of various levels of structure occurs simultaneously or in a hierarchal manner. We used various techniques such as circular dichroism, fluorescence spectroscopy, light scattering, polarization to determine the changes in secondary, tertiary, and quaternary structure. Unfolding and refolding occurred through a number of intermediates. The results showed that all levels of structure in alpha(L)-crystallin collapsed or reformed simultaneously. The intermediates that occurred in the 2-4 M urea concentration range during unfolding and refolding differed from each other in terms of the polarity of the tryptophan environment. The ANS binding experiments revealed that refolded alpha(L)-crystallin had higher number of hydrophobic pockets compared to native one. On the other hand, polarity of these pockets remained same as that of the native protein. Both light scattering and polarization measurements showed smaller oligomeric size of refolded alpha(L)-crystallin. Thus, although the secondary structural changes were almost reversible, the tertiary and quaternary structural changes were not. The refolded alpha(L)-crystallin had more exposed hydrophobic sites with increased binding affinity. The refolded form also showed higher chaperone activity than native one. Since the refolded form was smaller in oligomeric size, some buried hydrophobic sites were available. The higher chaperone activity of lower sized oligomer of alpha(L)-crystallin again revealed that chaperone activity was dependent on hydrophobicity and not on oligomeric size.
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Affiliation(s)
- S Saha
- Protein Chemistry Laboratory, Department of Chemistry, Bose Institute, 93/1 APC Road, Kolkata, 700 009, India
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Wu Z, Nagano I, Boonmars T, Takahashi Y. Thermally induced and developmentally regulated expression of a small heat shock protein in Trichinella spiralis. Parasitol Res 2007; 101:201-12. [PMID: 17268805 DOI: 10.1007/s00436-007-0462-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Accepted: 01/09/2007] [Indexed: 12/14/2022]
Abstract
A cDNA encoding a small heat shock protein of Trichinella spiralis, Ts-sHsp, was cloned and expressed and is herein characterized. This cDNA encoded a predicted protein of 165 amino acids, which had a high sequence identity in alpha crystallin domain with various small heat shock proteins of other organisms. A Western blot analysis indicated that anti-Ts-sHsp recombinant antibody recognized the protein of adults and larvae migrating at about 19 kDa. An in situ localization study showed the protein to be abundantly present in the body wall muscle cells, hypodermis, stichocytes, and esophagus of muscle larvae. The Ts-sHsp recombinant protein possessed chaperone activity to suppress the thermally-induced aggregation of citrate synthase. This sHsp was expressed at various developmental stages of T. spiralis, but at different levels. A high level was observed in mature muscle larvae (infective larvae), which was much higher than the levels seen in adults, newborn larvae, or immature muscle larvae. The expression of the sHsp gene was thermal inducible, thus responding to both cold (0 degrees C) and heat shock (43 degrees C) stress; however, at different patterns. The expression of Ts-sHsp increased gradually from 3 to 72 h after cold stress, while the expression was elevated to its highest after 3 h heat stress and then decreased. These results suggest that this small heat shock protein likely plays a role in the tolerance to both chemical and physical stresses, thereby enhancing the survival ability of Trichinella muscle larvae.
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Affiliation(s)
- Z Wu
- Department of Parasitology, Gifu University Graduate School of Medicine, Yanagido 1-1, Gifu 501-1194, Japan.
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15
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Manzer R, Pappa A, Estey T, Sladek N, Carpenter JF, Vasiliou V. Ultraviolet radiation decreases expression and induces aggregation of corneal ALDH3A1. Chem Biol Interact 2003; 143-144:45-53. [PMID: 12604188 DOI: 10.1016/s0009-2797(02)00171-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Substantial reduction in corneal ALDH3A1 enzymatic activity associated with eye pathology was previously reported in C57BL/6J mice subjected to ultraviolet radiation (UVR). The aim of this study was to examine whether UVR diminishes corneal ALDH3A1 expression through modifications at the transcriptional, translational, or post-translational level. Adult C57BL/6J mice were subjected to UVR exposure (302 nm peak wavelength) for various periods of time, and corneal ALDH3A1 mRNA and protein levels were monitored by Northern and Western blot analysis, respectively. In addition, ALDH3A1 enzymatic activity was determined as a measure of post-translational modification. Mice exposed to 0.2 J/cm(2) UVB radiation demonstrated an extensive decrease, approximately 80%, in mRNA and protein levels, as well as enzymatic activity of corneal ALDH3A1. Significant reductions in corneal ALDH3A1 enzymatic activity were detected in mice 96 h after exposure to 0.05 and 0.1 J/cm(2) UVB radiation; no significant changes were observed in mRNA and protein levels. These data suggest that UVB down-regulates corneal ALDH3A1 expression at the transcriptional and/or post-translational level depending on the dose of UVB. Reduction in gene transcription requires UVB doses greater than or equal to 0.2 J/cm(2). In vitro experiments with human corneal epithelial cell lines stably transfected with human ALDH3A1 cDNA, and with purified recombinant human ALDH3A1 protein, indicated that ALDH3A1 undergoes post-translational modifications after UVR exposure. These modifications result in both covalent and non-covalent aggregation of the protein with no detectable precipitation. Such conformational changes may be associated with the function of ALDH3A1 as a chaperone-like molecule in the cornea.
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Affiliation(s)
- Rizwan Manzer
- Molecular Toxicology and Environmental Health Sciences Program, Department of Pharmaceutical Sciences, University of Colorado Health Sciences Center, Denver, CO 80262, USA
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Liao JH, Lee JS, Chiou SH. Distinct roles of alphaA- and alphaB-crystallins under thermal and UV stresses. Biochem Biophys Res Commun 2002; 295:854-61. [PMID: 12127973 DOI: 10.1016/s0006-291x(02)00784-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
alpha-Crystallin, a major protein of all vertebrate lenses, consists of two subunits, alphaA and alphaB, which form polymeric aggregates with an average molecular mass of about 800kDa. In this study, we have employed various biophysical methods to study aggregate sizes and conformational properties of purified alphaA, alphaB subunits, and cloned recombinant alphaB subunit. From far- and near-UV CD spectra, native alpha-, alphaA-, alphaB-, and recombinant alphaB-crystallins from porcine lenses all show similar beta-sheet conformation to that from bovine and human lenses as reported previously. By means of gel-filtration chromatography and dynamic light scattering, we have found that the molecular sizes of all four crystallin aggregates are polydispersedly distributed in the following order of aggregate sizes, i.e., native alpha>alphaA>alphaB approximately recombinant alphaB. To investigate the structural and functional relationships, we have also compared the chaperone activities of all four alpha-crystallin aggregates at different temperatures. From the results of chaperone-activity assays, ANS (8-anilinonaphthalene-1-sulfonic acid) binding and thermal stability studies, there appeared to be at least two factors playing major roles in the chaperone-like activity of these lens proteins: one is the hydrophobicity of the exposed protein surface and the other is the structural stability associated with each protein. We showed that alphaA-crystallin is a better chaperone to protect gamma-crystallin against UV irradiation than alphaB-crystallin, in contrast to the observation that alphaB is generally a better chaperoning protein than alphaA for enzyme protective assays at physiological temperatures.
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Affiliation(s)
- Jiahn Haur Liao
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
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17
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Srinivas V, Santhoshkumar P, Sharma KK. Effect of trifluoroethanol on the structural and functional properties of alpha-crystallin. JOURNAL OF PROTEIN CHEMISTRY 2002; 21:87-95. [PMID: 11934279 DOI: 10.1023/a:1014572110926] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Alpha crystallin is an eye lens protein with a molecular weight of approximately 800 kDa. It belongs to the class of small heat shock proteins. Besides its structural role, it is known to prevent the aggregation of beta- and gamma-crystallins and several other proteins under denaturing conditions and is thus believed to play an important role in maintaining lens transparency. In this communication, we have investigated the effect of 2,2,2-trifluoroethanol (TFE) on the structural and functional features of the native alpha-crystallin and its two constituent subunits. A conformational change occurs from the characteristic beta-sheet to the alpha-helix structure in both native alpha-crystallin and its subunits with the increase in TFE levels. Among the two subunits, alphaA-crystallin is relatively stable and upon preincubation prevents the characteristic aggregation of alphaB-crystallin at 20% and 30% (v/v) TFE. The hydrophobicity and chaperone-like activity of the crystallin subunits decrease on TFE treatment. The ability of alphaA-crystallin to bind and prevent the aggregation of alphaB-crystallin, despite a conformational change, could be important in protecting the lens from external stress. The loss in chaperone activity of alphaA-crystallin exposed to TFE and the inability of peptide chaperone--the functional site of alphaA-crystallin--to stabilize alphaB-crystallin at 20-30% TFE suggest that the site(s) involved in subunit interaction and chaperone-like function are quite distinct.
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Affiliation(s)
- V Srinivas
- Department of Ophthalmology, University of Missouri, Columbia 65212, USA
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18
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Hernández-Quintero M, García-Villegas R, Castro-Muñozledo F. Differentiation-dependent increases in lactate dehydrogenase activity and isoenzyme expression in rabbit corneal epithelial cells. Exp Eye Res 2002; 74:71-82. [PMID: 11878820 DOI: 10.1006/exer.2001.1110] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Lactate dehydrogenase (LDH) and glucose-6-phosphate dehydrogenase (G-6-PDH) activities were studied during corneal epithelial growth and differentiation in cell culture. LDH and G-6-PDH activities increased up to 60 and 150-fold, respectively, when corneal epithelial cells constituted a differentiated four to five layered epithelium; these increases showed a similar time-course to the expression of K3 keratin. Immunostaining experiments showed that in growing colonies, LDH staining is stronger in those cells that are K3 positive; in contrast, in confluent four to five layered epithelia LDH and K3 were located in all cell layers, similar to the pattern found in frozen sections from rabbit central cornea. During growth and differentiation, the LDH isoenzyme set from corneal epithelial cells did not change; and it was different from those observed in cultured conjunctival, esophageal and epidermal cells. The augment in LDH activity was due to a 25-fold increase in the LDH-H mRNA and a 12-fold augment in LDH-M mRNA. A computer-assisted search led to identify AP2 and Sp1 binding sites in the LDH and G-6-PDH promoters, suggesting that their expression might share common regulatory mechanisms with the regulation of the differentiation-linked keratins. It is proposed that LDH may be an early marker of corneal epithelial differentiation, and its isozyme pattern could be distinctive from other epithelial cell lineages.
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Affiliation(s)
- Miriam Hernández-Quintero
- Department of Cell Biology, Centro de Investigación y Estudios Avanzados del IPN, Mexico City, Apdo, 07000, Mexico
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19
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Shroff NP, Bera S, Cherian-Shaw M, Abraham EC. Substituted hydrophobic and hydrophilic residues at methionine-68 influence the chaperone-like function of alphaB-crystallin. Mol Cell Biochem 2001. [PMID: 11451372 DOI: 10.1023/a: 1010834107809] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Amino acid residues 57-69 in alphaB-crystallin have been implicated as a target protein binding site. Moreover, a direct correlation between the extent of alpha-crystallin hydrophobicity and chaperone-like activity has been demonstrated. The purpose of this study was to mutate a moderately hydrophobic residue Met-68 (M-68) in the above region to strongly hydrophobic and hydrophilic residues and show whether chaperoning ability is affected with or without structural changes. Mutation of M-68 to Val, Ile or Thr did not result in significant changes in molecular mass and secondary and tertiary structures. However, the Val and Ile mutants showed significant improvement and the Thr mutant showed substantial loss in chaperone activity. Differences in chaperone function in the absence of any structural changes confirmed that the hydrophobicity or hydrophilicity of the substituted amino acid in the putative target protein binding site was the only contributing factor.
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Affiliation(s)
- N P Shroff
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock 72205, USA
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20
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Peluso G, Petillo O, Barbarisi A, Melone MA, Reda E, Nicolai R, Calvani M. Carnitine protects the molecular chaperone activity of lens alpha-crystallin and decreases the post-translational protein modifications induced by oxidative stress. FASEB J 2001; 15:1604-6. [PMID: 11427500 DOI: 10.1096/fj.00-0727fje] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- G Peluso
- Institute of Protein Biochemistry and Enzymology, C.N.R., Arco Felice, and Department of Experimental Oncology, National Cancer Institute, Naples, Italy.
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21
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Shroff NP, Bera S, Cherian-Shaw M, Abraham EC. Substituted hydrophobic and hydrophilic residues at methionine-68 influence the chaperone-like function of alphaB-crystallin. Mol Cell Biochem 2001; 220:127-33. [PMID: 11451372 DOI: 10.1023/a:1010834107809] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Amino acid residues 57-69 in alphaB-crystallin have been implicated as a target protein binding site. Moreover, a direct correlation between the extent of alpha-crystallin hydrophobicity and chaperone-like activity has been demonstrated. The purpose of this study was to mutate a moderately hydrophobic residue Met-68 (M-68) in the above region to strongly hydrophobic and hydrophilic residues and show whether chaperoning ability is affected with or without structural changes. Mutation of M-68 to Val, Ile or Thr did not result in significant changes in molecular mass and secondary and tertiary structures. However, the Val and Ile mutants showed significant improvement and the Thr mutant showed substantial loss in chaperone activity. Differences in chaperone function in the absence of any structural changes confirmed that the hydrophobicity or hydrophilicity of the substituted amino acid in the putative target protein binding site was the only contributing factor.
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Affiliation(s)
- N P Shroff
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock 72205, USA
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22
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Abstract
Alpha-crystallin, a large lenticular protein complex made up of two related subunits (alphaA- and alphaB-crystallin), is known to associate increasingly with fiber cell plasma membranes with age and/or the onset of cataract. To understand better the binding mechanism, we developed a sensitive membrane binding assay using lens plasma membranes and recombinant human alphaA- and alphaB-crystallins conjugated to a small fluorescent tag (Alexa350). Both alphaA and alphaB homopolymer complexes, as well as a reconstituted 3:1 heteromeric complex, bind to lens membranes in a specific, saturable, and partially irreversible manner that is sensitive to both time and temperature. The amount of alpha-crystallin that binds to the membrane increases under acidic pH conditions and upon removal of exposed intrinsic membrane protein domains but is not affected at high ionic strength, suggesting that alpha-crystallin binds to the fiber cell plasma membranes mainly through hydrophobic interactions. The binding capacity and affinity for the reconstituted 3:1 heteromeric complex were measured to be 3. 45 +/- 0.11 ng/microg of membrane and 4.57 +/- 0.50 x 10(-4) microg(-1) of membrane, respectively. The present membrane binding data support the hypothesis that the physical properties of a mixed alpha-crystallin complex may hold particular relevance for the function of alpha-crystallin within the lens.
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Affiliation(s)
- Brian A. Cobb
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri 63110
| | - J. Mark Petrash
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri 63110
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110
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23
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Kamińska A, Kowalska M. A study of the lens crystallin's photodegradation in the presence of β-carotene. Polym Degrad Stab 1999. [DOI: 10.1016/s0141-3910(99)00046-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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24
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Sharma KK, Kaur H, Kumar GS, Kester K. Interaction of 1,1'-bi(4-anilino)naphthalene-5,5'-disulfonic acid with alpha-crystallin. J Biol Chem 1998; 273:8965-70. [PMID: 9535881 DOI: 10.1074/jbc.273.15.8965] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The hydrophobic sites in alpha-crystallin were evaluated using a fluorescent probe 1,1'-bi(4-anilino)naphthalenesulfonic acid (bis-ANS). Approximately one binding site/subunit of alpha-crystallin at 25 degrees C was estimated by equilibrium binding and Scatchard analysis (Kd = 1.1 microM). Based on fluorescence titration, the dissociation constant was 0.95 microM. The number of bis-ANS binding sites nearly doubled upon heat treatment of the protein at 60 degrees C. Likewise, the exposure of alpha-crystallin to 2-3 M urea resulted in increased binding of bis-ANS. Above 3 M urea there was a rapid loss in the fluorescence indicating the loss of interaction between bis-ANS and protein. The alpha-crystallin refolded from 6 M urea showed tryptophan fluorescence emission similar to the native alpha-crystallin. However, the refolded alpha-crystallin showed a 60% increase in bis-ANS binding, suggesting distinct changes on the protein surface resulting from exposure to urea similar to the changes occurring due to heat treatment. The fluorescence of tryptophan in native alpha-crystallin was quenched by the addition of bis-ANS. The quenching was inversely related to the amount of bis-ANS bound to alpha-crystallin. Additionally, the binding of bis-ANS reduced the chaperone-like activity of the protein. Photolysis of bis-ANS-alpha-crystallin complex resulted in incorporation of the probe to both A- and B-subunits, indicating that both subunits in native alpha-crystallin contribute to the surface hydrophobicity of the protein.
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Affiliation(s)
- K K Sharma
- Mason Eye Institute, Department of Ophthalmology, University of Missouri, Columbia, Missouri 65212, USA.
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25
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Lee JS, Samejima T, Liao JH, Wu SH, Chiou SH. Physiological role of the association complexes of alpha-crystallin and its substrates on the chaperone activity. Biochem Biophys Res Commun 1998; 244:379-83. [PMID: 9514930 DOI: 10.1006/bbrc.1998.8272] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous reports on the chaperone activity of alpha-crystallin to prevent protein denaturation and thermal aggregation have suggested that partially denatured proteins can bind alpha-crystallin in its central region. Likewise, beta- and gamma-crystallin can also be localized to the central cavity of alpha-crystallin particle in vivo, which provides indirect evidence that alpha-crystallin can function as a chaperone in the intact lens. In this study, we have further demonstrated that the binding of the substrate proteins to alpha-crystallin by short-term preincubation may mimic the in vivo conditions of crystallin association. Preheating of alpha-crystallin with its substrate proteins at 60 degrees C for 20 min resulted in the formation of stable complexes between alpha-crystallin and its substrates (8.0% of insulin or 5.3% of gamma-crystallin was involved in complex formation). Under such conditions, the chaperone activity of alpha-crystallin to inhibit dithiothreitol-, ultraviolet-, or oxidation-induced protein aggregation can be greatly enhanced. Since UV-irradiation and oxidative stress are common insults to eye lenses under normal physiological conditions, the presence of alpha/gamma and alpha/beta complex in vivo may play an important role to maintain the lens in a transparent state.
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Affiliation(s)
- J S Lee
- Department of Ophthalmology, Chang-Gung Memorial Hospital, Taipei, Taiwan
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26
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Lee JS, Satoh T, Shinoda H, Samejima T, Wu SH, Chiou SH. Effect of heat-induced structural perturbation of secondary and tertiary structures on the chaperone activity of alpha-crystallin. Biochem Biophys Res Commun 1997; 237:277-82. [PMID: 9268700 DOI: 10.1006/bbrc.1997.7131] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
alpha-Crystallin, a major protein of the lens, is known to have chaperone activity to protect other proteins against thermal aggregation. Heat-induced structural change of alpha-crystallin was previously shown to increase its chaperone activity. In this report, we studied the thermal reversibility of alpha-crystallin and the effect of change in secondary structure on its chaperone function in vitro. The heat-induced conformational changes in the aromatic region of near-UV CD spectra showed only a small degree of reversibility. The structural transitions from 50 to 70 degrees C were largely reversible if the incubation time was short. However, the protective ability to inhibit thermal aggregation of alcohol dehydrogenase by alpha-crystallin was essentially similar at 48 and 70 degrees C. Under long-term heating at high temperatures, there was a time-dependent irreversibility of structural change in alpha-crystallin as revealed by CD spectroscopy. Such denatured alpha-crystallin by long-term heating can still preserve its ability to prevent UV-induced aggregation of gamma-crystallin at room temperature, indicating relatively little effect of heat-induced changes in secondary structure on the chaperone activity of alpha-crystallin.
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Affiliation(s)
- J S Lee
- Institute of Biochemical Sciences, Chang-Gung Memorial Hospital, Taipei, Academia, Taiwan
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