1
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Lin N, Song H, Zhang Y, Chen F, Xu J, Wu W, Tian Q, Luo C, Yao K, Hu L, Chen X. Truncation mutations of CRYGD gene in congenital cataracts cause protein aggregation by disrupting the structural stability of γD-crystallin. Int J Biol Macromol 2024; 277:134292. [PMID: 39084439 DOI: 10.1016/j.ijbiomac.2024.134292] [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: 05/10/2024] [Revised: 07/19/2024] [Accepted: 07/28/2024] [Indexed: 08/02/2024]
Abstract
Congenital cataracts, a prevalent cause of blindness in children, are associated with protein aggregation. γD-crystallin, essential for sustaining lens transparency, exists as a monomer and exhibits excellent structural stability. In our cohort, we identified a nonsense mutation (c.451_452insGACT, p.Y151X) in the CRYGD gene. To explore the effect of truncation mutations on the structure of γD-crystallin, we examined the Y151X and T160RfsX8 mutations, both located in the Greek key motif 4 at the cellular and protein level in this study. Both truncation mutations induced protein misfolding and resulted in the formation of insoluble aggregates when overexpressed in HLE B3 and HEK 293T cells. Moreover, heat, UV irradiation, and oxidative stress increased the proportion of aggregates of mutants in the cells. We next purified γD-crystallin to estimate its structural changes. Truncation mutations led to conformational disruption and a concomitant decrease in protein solubility. Molecular dynamics simulations further demonstrated that partial deletion of the conserved domain within the Greek key motif 4 markedly compromised the overall stability of the protein structure. Finally, co-expression of α-crystallins facilitated the proper folding of truncated mutants and mitigated protein aggregation. In summary, the structural integrity of the Greek key motif 4 in γD-crystallin is crucial for overall structural stability.
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Affiliation(s)
- Ningqin Lin
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China; Institute of Translational Medicine, Zhejiang University School of Medicine, 268 Kaixuan Road, Hangzhou 310020, China
| | - Hang Song
- Department of Ophthalmology, Peking Union Medical College Hospital, No.1 Shuaifuyuan, Beijing 100730, China
| | - Ying Zhang
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China; Institute of Translational Medicine, Zhejiang University School of Medicine, 268 Kaixuan Road, Hangzhou 310020, China
| | - Fanrui Chen
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jingjie Xu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China
| | - Wei Wu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China
| | - Qing Tian
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China; Institute of Translational Medicine, Zhejiang University School of Medicine, 268 Kaixuan Road, Hangzhou 310020, China
| | - Chenqi Luo
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China
| | - Ke Yao
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China
| | - Lidan Hu
- The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, 3333 Binsheng Road, Hangzhou 310052, China.
| | - Xiangjun Chen
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China; Institute of Translational Medicine, Zhejiang University School of Medicine, 268 Kaixuan Road, Hangzhou 310020, China.
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2
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Chen S, Guo J, Xu W, Song H, Xu J, Luo C, Yao K, Hu L, Chen X, Yu Y. Cataract-related variant R114C increases βA3-crystallin susceptibility to environmental stresses by disrupting the protein senior structure. Int J Biol Macromol 2024; 262:130191. [PMID: 38360245 DOI: 10.1016/j.ijbiomac.2024.130191] [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: 12/31/2023] [Revised: 02/12/2024] [Accepted: 02/12/2024] [Indexed: 02/17/2024]
Abstract
Congenital cataract is a major cause of childhood blindness worldwide, with crystallin mutations accounting for over 40 % of gene-mutation-related cases. Our research focused on a novel R114C mutation in a Chinese family, resulting in bilateral coronary cataract with blue punctate opacity. Spectroscopic experiments revealed that βA3-R114C significantly altered the senior structure, exhibiting aggregation, and reduced solubility at physiological temperature. The mutant also displayed decreased resistance and stability under environmental stresses such as UV irradiation, oxidative stress, and heat. Further, cellular models confirmed its heightened sensitivity to environmental stresses. These data suggest that the R114C mutation impairs the hydrogen bond network and structural stability of βA3-crystallin, particularly at the boundary of the second Greek-key motif. This study revealed the pathological mechanism of βA3-R114C and may help in the development of potential treatment strategies for related cataracts.
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Affiliation(s)
- Silong Chen
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China
| | - Jiarui Guo
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China
| | - Wanyue Xu
- Hangzhou TCM Hospital Affiliated to Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, China
| | - Hang Song
- Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Jingjie Xu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China
| | - Chenqi Luo
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China
| | - Ke Yao
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China
| | - Lidan Hu
- The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, Zhejiang Province 310052, China.
| | - Xiangjun Chen
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China; Institute of Translational Medicine, Zhejiang University School of Medicine, 268 Kaixuan Road, Hangzhou 310020, China.
| | - Yibo Yu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China.
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3
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Hashimi M, Amin HA, Zagkos L, Day AC, Drenos F. Using genetics to investigate the association between lanosterol and cataract. Front Genet 2024; 15:1231521. [PMID: 38440190 PMCID: PMC10910428 DOI: 10.3389/fgene.2024.1231521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 02/06/2024] [Indexed: 03/06/2024] Open
Abstract
Background: Cataract is one of the most prevalent causes of blindness worldwide. Whilst surgery is the primary treatment for cataracts, it is not always an available option, particularly in developing countries. Non-surgical methods of treatment would increase treatment availability for more patients. Several studies have investigated how topical application of oxysterols, such as lanosterol, may break down aggregated proteins and restore lens transparency. However, the results are conflicting and inconclusive. Aim: In this study, we focus on combining genetic evidence for associations between lanosterol related genetic variation and cataract to explore whether lanosterol is a potentially suitable drug treatment option. Method: Using data from 45,449 available cataract cases from the UK Biobank, with participant ages ranging from 40-69, we conducted a genetic association study (GWAS) to assess the risk of cataract. Cataract cases were defined using diagnostic and operation codes. We focused on genetic variants in the lanosterol synthase gene region. We also compared our results with previously published genetic associations of phytosterol-to-lanosterol ratios. Finally, we performed a genetic risk score analysis to test the association between lanosterol within the cholesterol synthesis pathway and the risk of cataract. Results: No statistically significant single nucleotide polymorphisms (SNPs) associations with cataract were observed in the gene region of lanosterol synthase at a multiple testing adjusted significance threshold of p < 0.05/13. The comparison between cataract risk and genetic association of 8 phytosterol-to-lanosterol GWAS results also showed no evidence to support lanosterol's protective properties for cataract risk. No statistically significant association was found between the lanosterol within the cholesterol synthesis pathway genetic risk score and cataract outcomes (OR = 1.002 p = 0.568). Conclusion: There was no evidence observed for genetic associations between lanosterol and cataract risk. Our results do not support lanosterol's potential role in treating cataracts. Further research may be needed to address the effect of lanosterol on specific cataract subtypes.
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Affiliation(s)
- Munisa Hashimi
- Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Hasnat A. Amin
- Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Loukas Zagkos
- Department of Epidemiology and Biostatistics, Imperial College London, London, United Kingdom
| | - Alexander C. Day
- Moorfields Eye Hospital, London, United Kingdom
- UCL Institute of Ophthalmology, London, United Kingdom
| | - Fotios Drenos
- Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, United Kingdom
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4
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Lin N, Zhang Y, Song X, Xu J, Luo C, Tian Q, Yao K, Wu W, Chen X, Hu L. Cataract-causing mutations S78F and S78P of γD-crystallin decrease protein conformational stability and drive aggregation. Int J Biol Macromol 2023; 253:126910. [PMID: 37739288 DOI: 10.1016/j.ijbiomac.2023.126910] [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: 07/03/2023] [Revised: 08/28/2023] [Accepted: 09/13/2023] [Indexed: 09/24/2023]
Abstract
Congenital cataract is the leading cause of childhood blindness, which primarily results from genetic factors. γD-crystallin is the most abundant γ-crystallin and is essential for maintaining lens transparency and refractivity. Numerous mutations in γD-crystallin have been reported with unclear pathogenic mechanism. Two different cataract-causing mutations Ser78Phe and Ser78Pro in γD-crystallin were previously identified at the same conserved Ser78 residue. In this work, firstly, we purified the mutants and characterized for the structural change using fluorescence spectroscopy, circular dichroism (CD) spectroscopy, and size-exclusion chromatography (SEC). Both mutants were prone to form insoluble precipitates when expressed in Escherichia coli strain BL21 (DE3) cells. Compared with wild-type (WT), both mutations caused structural disruption, increased hydrophobic exposure, decreased solubility, and reduced thermal stability. Next, we investigated the aggregation of the mutants at the cellular level. Overexpression the mutants in HLE-B3 and HEK 293T cells could induce aggresome formations. The environmental stresses (including heat, ultraviolet irradiation and oxidative stress) promoted the formation of aggregates. Moreover, the intracellular S78F and S78P aggregates could be reversed by lanosterol. Molecular dynamic simulation indicated that both mutations disrupted the structural integrity of Greek-key motif 2. Hence, our results reveal the vital role of conserved Ser78 in maintaining the structural stability, which can offer new insights into the mechanism of cataract formation.
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Affiliation(s)
- Ningqin Lin
- Department of Nephrology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, Zhejiang Province, China; Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China; Institute of Translational Medicine, Zhejiang University School of Medicine, 268 Kaixuan Road, Hangzhou 310020, China
| | - Ying Zhang
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China; Institute of Translational Medicine, Zhejiang University School of Medicine, 268 Kaixuan Road, Hangzhou 310020, China
| | - Xiaohui Song
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China
| | - Jingjie Xu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China
| | - Chenqi Luo
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China
| | - Qing Tian
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China; Institute of Translational Medicine, Zhejiang University School of Medicine, 268 Kaixuan Road, Hangzhou 310020, China
| | - Ke Yao
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China
| | - Wei Wu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China.
| | - Xiangjun Chen
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China; Institute of Translational Medicine, Zhejiang University School of Medicine, 268 Kaixuan Road, Hangzhou 310020, China.
| | - Lidan Hu
- Department of Nephrology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, Zhejiang Province, China.
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5
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Lacoste J, Haghighi M, Haider S, Lin ZY, Segal D, Reno C, Qian WW, Xiong X, Shafqat-Abbasi H, Ryder PV, Senft R, Cimini BA, Roth FP, Calderwood M, Hill D, Vidal M, Yi SS, Sahni N, Peng J, Gingras AC, Singh S, Carpenter AE, Taipale M. Pervasive mislocalization of pathogenic coding variants underlying human disorders. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.05.556368. [PMID: 37732209 PMCID: PMC10508771 DOI: 10.1101/2023.09.05.556368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Widespread sequencing has yielded thousands of missense variants predicted or confirmed as disease-causing. This creates a new bottleneck: determining the functional impact of each variant - largely a painstaking, customized process undertaken one or a few genes or variants at a time. Here, we established a high-throughput imaging platform to assay the impact of coding variation on protein localization, evaluating 3,547 missense variants of over 1,000 genes and phenotypes. We discovered that mislocalization is a common consequence of coding variation, affecting about one-sixth of all pathogenic missense variants, all cellular compartments, and recessive and dominant disorders alike. Mislocalization is primarily driven by effects on protein stability and membrane insertion rather than disruptions of trafficking signals or specific interactions. Furthermore, mislocalization patterns help explain pleiotropy and disease severity and provide insights on variants of unknown significance. Our publicly available resource will likely accelerate the understanding of coding variation in human diseases.
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Affiliation(s)
- Jessica Lacoste
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Canada
- These authors contributed equally
| | - Marzieh Haghighi
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
- These authors contributed equally
| | - Shahan Haider
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Canada
| | - Zhen-Yuan Lin
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto, Canada
| | - Dmitri Segal
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Canada
| | - Chloe Reno
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Canada
| | - Wesley Wei Qian
- Department of Computer Science, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Xueting Xiong
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Canada
| | | | | | - Rebecca Senft
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | | | - Frederick P. Roth
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Canada
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto, Canada
- Department of Computer Science, University of Toronto, Toronto, Ontario, Canada
| | - Michael Calderwood
- Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - David Hill
- Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Marc Vidal
- Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - S. Stephen Yi
- Livestrong Cancer Institutes, Department of Oncology, Dell Medical School, The University of Texas at Austin, Austin, TX, USA
- Oden Institute for Computational Engineering and Sciences (ICES), The University of Texas at Austin, Austin, TX, USA
- Department of Biomedical Engineering, Cockrell School of Engineering, The University of Texas at Austin, Austin, TX, USA
- Interdisciplinary Life Sciences Graduate Programs (ILSGP), College of Natural Sciences, The University of Texas at Austin, Austin, TX, USA
| | - Nidhi Sahni
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Quantitative and Computational Biosciences Program, Baylor College of Medicine, Houston, TX, USA
| | - Jian Peng
- Department of Computer Science, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Anne-Claude Gingras
- Department of Molecular Genetics, University of Toronto, Canada
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto, Canada
| | | | | | - Mikko Taipale
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Canada
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6
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Jing X, Zhu M, Lu X, Wei P, Shi L, Zhang BY, Xu Y, Tang YP, Xiang DM, Gong P. Cataract-causing Y204X mutation of crystallin protein CRYβB1 promotes its C-terminal degradation and higher-order oligomerization. J Biol Chem 2023; 299:104953. [PMID: 37356717 PMCID: PMC10382669 DOI: 10.1016/j.jbc.2023.104953] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/16/2023] [Accepted: 06/19/2023] [Indexed: 06/27/2023] Open
Abstract
Crystallin proteins are a class of main structural proteins of the vertebrate eye lens, and their solubility and stability directly determine transparency and refractive power of the lens. Mutation in genes that encode these crystallin proteins is the most common cause for congenital cataracts. Despite extensive studies, the pathogenic and molecular mechanisms that effect congenital cataracts remain unclear. In this study, we identified a novel mutation in CRYBB1 from a congenital cataract family, and demonstrated that this mutation led to an early termination of mRNA translation, resulting in a 49-residue C-terminally truncated CRYβB1 protein. We show this mutant is susceptible to proteolysis, which allowed us to determine a 1.2-Å resolution crystal structure of CRYβB1 without the entire C-terminal domain. In this crystal lattice, we observed that two N-terminal domain monomers form a dimer that structurally resembles the WT monomer, but with different surface characteristics. Biochemical analyses and cell-based data also suggested that this mutant is significantly more liable to aggregate and degrade compared to WT CRYβB1. Taken together, our results provide an insight into the mechanism regarding how a mutant crystalin contributes to the development of congenital cataract possibly through alteration of inter-protein interactions that result in protein aggregation.
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Affiliation(s)
- Xuping Jing
- Joint Laboratory for Translational Precision Medicine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China; Joint Laboratory for Translational Precision Medicine, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China; Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Mingwei Zhu
- Joint Laboratory for Translational Precision Medicine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China; Joint Laboratory for Translational Precision Medicine, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Xiaoyun Lu
- Joint Laboratory for Translational Precision Medicine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China; Joint Laboratory for Translational Precision Medicine, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Ping Wei
- Joint Laboratory for Translational Precision Medicine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China; Joint Laboratory for Translational Precision Medicine, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Lingyu Shi
- Department of Ophthalmology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Bu-Yu Zhang
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yi Xu
- Joint Laboratory for Translational Precision Medicine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China; Joint Laboratory for Translational Precision Medicine, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Ya-Ping Tang
- Joint Laboratory for Translational Precision Medicine, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China; Joint Laboratory for Translational Precision Medicine, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China; Goungdong Key Laboratory of Structural Birth Defects, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China; Department of Imaging, Affiliated Hospital 3, Zhengzhou University, Zhengzhou, Henan, China.
| | - Dao-Man Xiang
- Department of Ophthalmology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China.
| | - Peng Gong
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China.
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7
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Zhang Y, Ren L, Wu W, Liu J, Tian Q, Yao K, Yu Y, Hu L, Chen X. Cataract-causing variant Q70P damages structural stability of βB1-crystallin and increases its tendency to form insoluble aggregates. Int J Biol Macromol 2023; 242:124722. [PMID: 37148932 DOI: 10.1016/j.ijbiomac.2023.124722] [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: 11/16/2022] [Revised: 04/28/2023] [Accepted: 04/30/2023] [Indexed: 05/08/2023]
Abstract
Congenital cataract is the primary cause of childhood blindness worldwide. As the predominant structural protein, βB1-crystallin plays an important role in maintaining lens transparency and cellular homeostasis. Numerous cataract-causing mutations of βB1-crystallin have been identified with unclear pathogenic mechanism. We previously identified the mutation Q70P (Q to P at residue position 70) of βB1-crystallin linked to congenital cataract in a Chinese family. In this work, we investigated the potential molecular mechanism of βB1-Q70P in the congenital cataract at the molecular, protein, and cellular levels. We purified recombinant βB1 wild-type (WT) and Q70P proteins and compared their structural characteristics and biophysical properties by spectroscopic experiments under physiological temperature and environmental stresses (ultraviolet irradiation, heat stress, oxidative stress). Notably, βB1-Q70P significantly changed the structures of βB1-crystallin and exhibited lower solubility at physiological temperature. Meanwhile, βB1-Q70P was prone to aggregation in eukaryotic and prokaryotic cells, and was more sensitive to environmental stresses, along with impaired cellular viability. Furthermore, the molecular dynamics simulation indicated that the mutation Q70P damaged secondary structures and hydrogen bond network of βB1-crystallin, which were essential for the first Greek-key motif. This study delineated the pathological mechanism of βB1-Q70P and provided novel insights into treatment and prevention strategies for cataract-associated βB1 mutations.
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Affiliation(s)
- Ying Zhang
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China; Institute of Translational Medicine, Zhejiang University School of Medicine, 268 Kaixuan Road, Hangzhou 310020, China
| | - Ling Ren
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China
| | - Wei Wu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China
| | - Jian Liu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China; Eye Center of Zhejiang Hospital, Zhejiang University School of Medicine, 12 Lingyin Road, Hangzhou 310012, China
| | - Qing Tian
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China; Institute of Translational Medicine, Zhejiang University School of Medicine, 268 Kaixuan Road, Hangzhou 310020, China
| | - Ke Yao
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China
| | - Yibo Yu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China.
| | - Lidan Hu
- The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, Zhejiang Province 310052, China.
| | - Xiangjun Chen
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China; Institute of Translational Medicine, Zhejiang University School of Medicine, 268 Kaixuan Road, Hangzhou 310020, China.
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8
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Xu W, Xu J, Shi C, Wu J, Wang H, Wu W, Chen X, Hu L. A novel cataract-causing mutation Ile82Met of γA crystallin trends to aggregate with unfolding intermediate. Int J Biol Macromol 2022; 211:357-367. [PMID: 35513103 DOI: 10.1016/j.ijbiomac.2022.04.205] [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: 12/04/2021] [Revised: 02/06/2022] [Accepted: 04/27/2022] [Indexed: 11/05/2022]
Abstract
Cataract is the most common pathogenic ophthalmic disease leading to blindness in children worldwide. Genetic disorder is the leading cause of congenital cataract, among which crystallin mutations have a high incidence. There are few reports on γA-crystallin, one critical member of crystallin superfamilies. In this study, we identified a novel pathogenic mutation (Ile82Met) in γA-crystallin from a three-generation Chinese family with cataract, and investigated the potential molecular mechanism in detail. To elucidate the pathogenic mechanism of I82M mutant, spectroscopic and solubility experiments were performed to determine the difference between the purified γA-crystallin wild type (WT) and I82M mutant under both physiological conditions and environmental stresses (UV irradiation, thermal denaturation or chemical denaturation). The I82M mutant did not affect the secondary/tertiary structure of monomeric γA-crystallin under physiological status, but decreased protein stability and increased aggregatory potency under the stressful treatment. Surprisingly, the chemical denaturation caused I82M to switch from the two-state unfolding of γA-crystallin to three-state unfolding involving an unfolding intermediate. This study expands the genetic variation map of cataract, and provides novel insights into the pathomechanism, in particular, filling in a gap in the understanding of γA-crystallin mutants causing cataract.
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Affiliation(s)
- Wanyue Xu
- The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou 310052, China; Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China; Institute of Translational Medicine, Zhejiang University School of Medicine, 268 Kaixuan Road, Hangzhou 310020, China
| | - Jingjie Xu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China
| | - Caiping Shi
- The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou 310052, China
| | - Jing Wu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China
| | - Huaxia Wang
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China; Institute of Translational Medicine, Zhejiang University School of Medicine, 268 Kaixuan Road, Hangzhou 310020, China
| | - Wei Wu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China
| | - Xiangjun Chen
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China; Institute of Translational Medicine, Zhejiang University School of Medicine, 268 Kaixuan Road, Hangzhou 310020, China.
| | - Lidan Hu
- The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou 310052, China.
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9
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Ren L, Hu L, Zhang Y, Liu J, Xu W, Wu W, Xu J, Chen X, Yao K, Yu Y. Cataract-Causing S93R Mutant Destabilized Structural Conformation of βB1 Crystallin Linking With Aggregates Formation and Cellular Viability. Front Mol Biosci 2022; 9:844719. [PMID: 35359596 PMCID: PMC8964140 DOI: 10.3389/fmolb.2022.844719] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 02/22/2022] [Indexed: 12/14/2022] Open
Abstract
Cataract, opacity of the eye lens, is the leading cause of visual impairment worldwide. The crucial pathogenic factors that cause cataract are misfolding and aggregation of crystallin protein. βB1-crystallin, which is the most abundant water-soluble protein in mammalian lens, is essential for lens transparency. A previous study identified the missense mutation βB1-S93R being responsible for congenital cataract. However, the exact pathogenic mechanism causing cataract remains unclear. The S93 residue, which is located at the first Greek-key motif of βB1-crystallin, is highly conserved, and its substitution to Arginine severely impaired hydrogen bonds and structural conformation, which were evaluated via Molecular Dynamic Simulation. The βB1-S93R was also found to be prone to aggregation in both human cell lines and Escherichia coli. Then, we isolated the βB1-S93R variant from inclusion bodies by protein renaturation. The βB1-S93R mutation exposed more hydrophobic residues, and the looser structural mutation was prone to aggregation. Furthermore, the S93R mutation reduced the structural stability of βB1-crystallin when incubated at physiological temperature and made it more sensitive to environmental stress, such as UV irradiation or oxidative stress. We also constructed a βB1-S93R cellular model and discovered that βB1-S93R was more sensitive to environmental stress, causing not only aggregate formation but also cellular apoptosis and impaired cellular viability. All of the results indicated that lower solubility and structural stability, sensitivity to environmental stress, vulnerability to aggregation, and impaired cellular viability of βB1-S93R might be involved in cataract development.
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Affiliation(s)
- Ling Ren
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Lidan Hu
- National Clinical Research Center for Child Health, The Children’s Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Ying Zhang
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Jian Liu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Eye Center of Zhejiang Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Wanyue Xu
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Wei Wu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jingjie Xu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiangjun Chen
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Ke Yao
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yibo Yu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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10
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Liu J, Xu W, Wang K, Chen F, Ren L, Xu J, Yao K, Chen X. Congenital cataract-causing mutation βB1-L116P is prone to amyloid fibrils aggregation and protease degradation with low structural stability. Int J Biol Macromol 2022; 195:475-482. [PMID: 34896472 DOI: 10.1016/j.ijbiomac.2021.12.044] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/24/2021] [Accepted: 12/06/2021] [Indexed: 12/24/2022]
Abstract
Congenital cataract, a common disease with lens opacification, causes blindness in the newborn worldwide and is mainly caused by abnormal aggregation of crystallin. As the main structural protein in the mammalian lens, βB1-crystallin has an important role in the maintenance of lens transparency. Recently, the L116P mutation in βB1-CRY was found in a Chinese family with congenital nuclear cataracts, while its underlying pathogenic mechanism remains unclear. In the current study, the βB1 wild-type protein was purified, and the mutated form, βB1-L116P, was examined for examining the effect on structural stability and susceptibility against environmental stresses. Our results reveal low solubility and structural stability of βB1-L116P at physiological temperature, which markedly impaired the protein structure and the oligomerization of βB1-crystallin. Under guanidine hydrochloride-induced denaturing conditions, βB1-L116P mutation perturbed the protein unfolding process, making it prone to amyloid fibrils aggregation. More importantly, the L116P mutation increased susceptibility of βB1-crystallin against UV radiation. βB1-L116P overexpression led to the formation of more serious intracellular aggresomes under UV radiation or oxidative stress. Furthermore, the βB1-L116P mutation increased the sensitivity to the proteolysis process. These results indicate that the low structural stability, susceptibility to amyloid fibrils aggregation, and protease degradation of βB1-L116P may contribute to cataract development and associated symptoms.
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Affiliation(s)
- Jian Liu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China; Eye Center of Zhejiang Hospital, Zhejiang University School of Medicine, 12 Lingyin Road, Hangzhou 310012, China
| | - Wanyue Xu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China; Institute of Translational Medicine, Zhejiang University School of Medicine, 268 Kaixuan Road, Hangzhou 310020, China
| | - Kaijie Wang
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology &Visual Sciences Key Lab, Beijing 100062, China
| | - Fanrui Chen
- College of International Education, Xinyang Normal University, No.237 Nanhu Road, Xinyang 464000, China
| | - Ling Ren
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China
| | - Jingjie Xu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China
| | - Ke Yao
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China.
| | - Xiangjun Chen
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, China; Institute of Translational Medicine, Zhejiang University School of Medicine, 268 Kaixuan Road, Hangzhou 310020, China.
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11
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Patel S, Hosur RV. Replica exchange molecular dynamics simulations reveal self-association sites in M-crystallin caused by mutations provide insights of cataract. Sci Rep 2021; 11:23270. [PMID: 34857812 PMCID: PMC8639718 DOI: 10.1038/s41598-021-02728-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 11/09/2021] [Indexed: 11/09/2022] Open
Abstract
Crystallins are ubiquitous, however, prevalence is seen in eye lens. Eye lens crystallins are long-lived and structural intactness is required for maintaining lens transparency and protein solubility. Mutations in crystallins often lead to cataract. In this study, we performed mutations at specific sites of M-crystallin, a close homologue of eye lens crystallin and studied by using replica exchange molecular dynamics simulation with generalized Born implicit solvent model. Mutations were made on the Ca2+ binding residues (K34D and S77D) and in the hydrophobic core (W45R) which is known to cause congenital cataract in homologous γD-crystallin. The chosen mutations caused large motion of the N-terminal Greek key, concomitantly broke the interlocking Greek keys interactions and perturbed the compact core resulting in several folded and partially unfolded states. Partially unfolded states exposed large hydrophobic patches that could act as precursors for self-aggregation. Accumulation of such aggregates is the potential cause of cataract in homologous eye lens crystallins.
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Affiliation(s)
- Sunita Patel
- UM-DAE Centre for Excellence in Basic Sciences, Mumbai University Campus, Vidyanagari, Mumbai, 400098, India.
| | - Ramakrishna V. Hosur
- grid.452882.1UM-DAE Centre for Excellence in Basic Sciences, Mumbai University Campus, Vidyanagari, Mumbai, 400098 India
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12
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Chen X, Xu J, Chen X, Yao K. Cataract: Advances in surgery and whether surgery remains the only treatment in future. ADVANCES IN OPHTHALMOLOGY PRACTICE AND RESEARCH 2021; 1:100008. [PMID: 37846393 PMCID: PMC10577864 DOI: 10.1016/j.aopr.2021.100008] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/27/2021] [Accepted: 10/12/2021] [Indexed: 10/18/2023]
Abstract
Background Cataract is the world's leading eye disease that causes blindness. The prevalence of cataract aged 40 years and older is approximately 11.8%-18.8%. Currently, surgery is the only way to treat cataracts. Main Text From early intracapsular cataract extraction to extracapsular cataract extraction, to current phacoemulsification cataract surgery, the incision ranges from 12 to 3 mm, and sometimes to even 1.8 mm or less, and the revolution in cataract surgery is ongoing. Cataract surgery has transformed from vision recovery to refractive surgery, leading to the era of refractive cataract surgery, and premium intraocular lenses (IOLs) such as toric IOLs, multifocal IOLs, and extended depth-of-focus IOLs are being increasingly used to meet the individual needs of patients. With its advantages of providing better visual acuity and causing fewer complications, phacoemulsification is currently the mainstream cataract surgery technique worldwide. However, patient expectations for the safety and accuracy of the operation are continually increasing. Femtosecond laser-assisted cataract surgery (FLACS) has entered the public's field of vision. FLACS is a combination of new laser technology and artificial intelligence to replace fine manual clear corneal incision, capsulorhexis, and nuclear pre-fragmentation, providing new alternative technologies for patients and ophthalmologists. As FLACS matures, it is being increasingly applied in complex cases; however, some think it is not cost-effective. Although more than 26 million cataract surgeries are performed each year, there is still a gap in the prevalence of cataracts, especially in developing countries. Although cataract surgery is a nearly ideal procedure and complications are manageable, both patients and doctors dream of using drugs to cure cataracts. Is surgery really the only way to treat cataracts in the future? It has been verified by animal experiments that lanosterol therapy in rabbits and dogs could make cataract severity alleviated and lens transparency partially recovered. Although there is still much to learn about cataract reversal, this groundbreaking work provided a new strategy for the prevention and treatment of cataracts. Conclusions Although cataract surgery is nearly ideal, it is still insufficient, we expect the prospects for cataract drugs to be bright.
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Affiliation(s)
- Xinyi Chen
- Eye Center, Second Affiliated Hospital of School of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310009, China
| | - Jingjie Xu
- Eye Center, Second Affiliated Hospital of School of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310009, China
| | - Xiangjun Chen
- Eye Center, Second Affiliated Hospital of School of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310009, China
| | - Ke Yao
- Eye Center, Second Affiliated Hospital of School of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310009, China
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13
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Ou X, Lao Y, Xu J, Wutthinitikornkit Y, Shi R, Chen X, Li J. ATP Can Efficiently Stabilize Protein through a Unique Mechanism. JACS AU 2021; 1:1766-1777. [PMID: 34723279 PMCID: PMC8549052 DOI: 10.1021/jacsau.1c00316] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Indexed: 06/13/2023]
Abstract
Recent experiments suggested that ATP can effectively stabilize protein structure and inhibit protein aggregation when its concentration is less than 10 mM, which is significantly lower than cosolvent concentrations required in conventional mechanisms. The ultrahigh efficiency of ATP suggests a unique mechanism that is fundamentally different from previous models of cosolvents. In this work, we used molecular dynamics simulation and experiments to study the interactions of ATPs with three proteins: lysozyme, ubiquitin, and malate dehydrogenase. ATP tends to bind to the surface regions with high flexibility and high degree of hydration. These regions are also vulnerable to thermal perturbations. The bound ATPs further assemble into ATP clusters mediated by Mg2+ and Na+ ions. More interestingly, in Mg2+-free ATP solution, Na+ at higher concentration (150 mM under physiological conditions) can similarly mediate the formation of the ATP cluster on protein. The ATP cluster can effectively reduce the fluctuations of the vulnerable region and thus stabilize the protein against thermal perturbations. Both ATP binding and the considerable improvement of thermal stability of ATP-bound protein were verified by experiments.
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Affiliation(s)
- Xinwen Ou
- Zhejiang
Province Key Laboratory of Quantum Technology and Device, Department
of Physics, Zhejiang University, Zheda Road 38, Hangzhou 310027, China
| | - Yichong Lao
- Zhejiang
Province Key Laboratory of Quantum Technology and Device, Department
of Physics, Zhejiang University, Zheda Road 38, Hangzhou 310027, China
| | - Jingjie Xu
- Eye
Center of the Second Affiliated Hospital, Institute of Translational
Medicine, School of Medicine, Zhejiang University, Hangzhou 310009, China
| | - Yanee Wutthinitikornkit
- Zhejiang
Province Key Laboratory of Quantum Technology and Device, Department
of Physics, Zhejiang University, Zheda Road 38, Hangzhou 310027, China
| | - Rui Shi
- Zhejiang
Province Key Laboratory of Quantum Technology and Device, Department
of Physics, Zhejiang University, Zheda Road 38, Hangzhou 310027, China
| | - Xiangjun Chen
- Eye
Center of the Second Affiliated Hospital, Institute of Translational
Medicine, School of Medicine, Zhejiang University, Hangzhou 310009, China
| | - Jingyuan Li
- Zhejiang
Province Key Laboratory of Quantum Technology and Device, Department
of Physics, Zhejiang University, Zheda Road 38, Hangzhou 310027, China
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14
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Wang H, Tian Q, Xu J, Xu W, Yao K, Chen X. Cataract-causing G91del mutant destabilised βA3 heteromers formation linking with structural stability and cellular viability. Br J Ophthalmol 2021; 106:1473-1478. [PMID: 34489339 DOI: 10.1136/bjophthalmol-2021-320033] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 08/27/2021] [Indexed: 11/04/2022]
Abstract
BACKGROUND/AIMS Congenital cataracts, which are genetically heterogeneous eye disorders, result in visual loss in childhood around the world. CRYBA1/BA3 serves as an abundant structural protein in the lens, and forms homomers and heteromers to maintain lens transparency. In previous study, we identified a common cataract-causing mutation, βA3-glycine at codon 91 (G91del) (c.271-273delGAG), which deleted a highly conserved G91del and led to perinuclear zonular cataract. In this study, we aimed to explore the underlying pathogenic mechanism of G91del mutation. METHODS Protein purification, size-exclusion chromatography, spectroscopy and molecular dynamics simulation assays were used to investigate the effects on the heteromers formation and the protein structural properties of βA3-crystallin caused by G91del mutation. Intracellular βA3-G91del overexpression, MTT (3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide) and cell apoptosis were used to investigate the cellular functions of βA3-G91del. RESULTS βA3-crystallin and βB2-crystallin could form heteromers, which have much more stable structures than βA3 homomers. Interestingly, βA3/βB2 heteromers improved their resistance against the thermal stress and the guanidine hydrochloride treatment. However, the pathogenic mutation βA3-G91del destroyed the interaction with βB2, and thereby decreased its structural stability as well as the resistance of thermal or chemical stress. What's more, the βA3-G91del mutation induced cell apoptosis and escaped from the protection of βB2-crystallin. CONCLUSIONS βA3/βB2 heteromers play an indispensable role in maintaining lens transparency, while the βA3-G91del mutation destabilises heteromers formation with βB2-crystallin, impairs cellular viability and induces cellular apoptosis. These all might contribute to cataract development.
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Affiliation(s)
- Huaxia Wang
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Qing Tian
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Jingjie Xu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Wanyue Xu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.,Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Ke Yao
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xiangjun Chen
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China .,Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
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15
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Yu Y, Qiao Y, Ye Y, Li J, Yao K. Identification and characterization of six β-crystallin gene mutations associated with congenital cataract in Chinese families. Mol Genet Genomic Med 2021; 9:e1617. [PMID: 33594837 PMCID: PMC8104166 DOI: 10.1002/mgg3.1617] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 12/28/2020] [Accepted: 01/18/2021] [Indexed: 12/21/2022] Open
Abstract
Background This study aims to identify the underlying genetic defects of β‐crystallin (CRYB) genes responsible for congenital cataracts in a group of Chinese families. Methods Detailed family history and clinical data of six Chinese families with autosomal dominant congenital cataracts were recorded. Targeted exome sequencing was applied to detect the underlying genetic defects for the families. Generated variants were confirmed by PCR and sanger sequencing. Afterward, bioinformatic analysis through several computational predictive programs was performed to assess impacts of mutations on protein structure and function. Results A total of 53 participants (23 affected and 30 unaffected) from six unrelated Chinese families were recruited. Cataract phenotypes covered nuclear, total, posterior polar, pulverulent, snowflake‐like, and zonular. Through targeted exome sequencing, six mutations in four β‐crystallin genes were revealed which included five missense mutations CRYBB1 p.Q70P, CRYBB2 p.E23Q, CRYBB2 p.A49V, CRYBB2 R188C, CRYBA4 p.M14K and one splice mutation CRYBB3 c.75+1 G>A. In silico results predicted pathogenic for all four missense variants except variant CRYBB2‐p.A49V yielded results as tolerant. The CRYBB3 c.75+1 G>A splice site mutation was predicted to be deleterious by leading to a broken splice site, a premature stop codon, and subsequently resulting in a short peptide of 113 amino acids, which may affect protein features. Conclusion The obtained results expanded mutational and phenotype spectrum of β‐crystallin genes and offer clues for pathogenesis of congenital cataracts. The data also demonstrated that targeted exome sequencing is valuable for providing molecular diagnostic information for congenital cataract patients.
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Affiliation(s)
- Yinhui Yu
- Department of Eye Center, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China.,Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou, Zhejiang Province, China
| | - Yue Qiao
- Department of Eye Center, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China.,Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou, Zhejiang Province, China
| | - Yang Ye
- Department of Eye Center, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China.,Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou, Zhejiang Province, China
| | - Jinyu Li
- Department of Eye Center, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China.,Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou, Zhejiang Province, China
| | - Ke Yao
- Department of Eye Center, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China.,Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou, Zhejiang Province, China
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16
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Wang KJ, Liao XY, Lin K, Xi YB, Wang S, Wan XH, Yan YB. A novel F30S mutation in γS-crystallin causes autosomal dominant congenital nuclear cataract by increasing susceptibility to stresses. Int J Biol Macromol 2021; 172:475-482. [PMID: 33454329 DOI: 10.1016/j.ijbiomac.2021.01.079] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 01/03/2021] [Accepted: 01/12/2021] [Indexed: 01/14/2023]
Abstract
Despite of increasingly accumulated genetic variations of autosomal dominant congenital cataracts (ADCC), the causative genes of many ADCC patients remains unknown. In this research, we identified a novel F30S mutation in γS-crystallin from a three-generation Chinese family with ADCC. The patients possessing the F30S mutation exhibited nuclear cataract phenotype. The potential molecular mechanism underlying ADCC by the F30S mutation was investigated by comparing the structural features, stability and aggregatory potency of the mutated protein with the wild type protein. Spectroscopic experiments indicated that the F30S mutation did not affect γS-crystallin secondary structure compositions, but modified the microenvironments around aromatic side-chains. Thermal and chemical denaturation studies indicated that the mutation destabilized the protein and increased its aggregatory potency. The mutation altered the two-state unfolding of γS-crystallin to a three-state unfolding with the accumulation of an unfolding intermediate. The almost identical values in the changes of Gibbs free energies for transitions from the native state to intermediate and from the intermediate to unfolded state suggested that the mutation probably disrupted the cooperativity between the two domains during unfolding. Our results expand the genetic variation map of ADCC and provide novel insights into the molecular mechanism underlying ADCC caused by mutations in β/γ-crystallins.
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Affiliation(s)
- Kai-Jie Wang
- Beijing Tongren Eye Center, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China
| | - Xiao-Yan Liao
- State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Kunxia Lin
- Ophthalmology Department, Fujian Provincial Hospital, Fuzhou, 350001, China
| | - Yi-Bo Xi
- State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Sha Wang
- State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiu-Hua Wan
- Beijing Tongren Eye Center, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China.
| | - Yong-Bin Yan
- State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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17
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Fu C, Xu J, Yang X, Chen X, Yao K. Cataract-causing mutations L45P and Y46D impair the thermal stability of γC-crystallin. Biochem Biophys Res Commun 2021; 539:70-76. [PMID: 33422942 DOI: 10.1016/j.bbrc.2020.12.096] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 12/28/2020] [Indexed: 10/22/2022]
Abstract
Crystallin gene mutations are responsible for about half of the congenital cataract caused by genetic disorders. L45P and Y46D mutations of γC-crystallin have been reported in patients with nuclear congenital cataract. In this study, we explored the thermal stability of wild type (WT), L45P, and Y46D mutants of γC-crystallin at low and high concentrations, as well as the effect of αA-crystallin on the thermal stability of mutants. Spectroscopic experiments were used to monitor the structural changes on temperature-gradient and time-course heating process. Intermediate morphologies were determined through cryo-electron microscopy. The thermal stability of WT and mutants at concentrations ranging up to hundreds of milligrams were assessed via the UNcle multifunctional protein stability analysis system. The results showed that L45P and Y46D mutations impaired the thermal stability of γC-crystallin at low (0.2 mg/mL) and high concentrations (up to 200 mg/mL). Notably, with increase in protein concentration, the thermal stability of L45P and Y46D mutants of γC-crystallin simultaneously decreased. Thermal stability of L45P and Y46D mutants could be rescued by αA-crystallin in a concentration-dependent manner. The dramatic decrease in thermal stability of γC-crystallin caused by L45P and Y46D mutations contributed to congenital cataract in the mature human lens.
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Affiliation(s)
- Chenxi Fu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009, China
| | - Jingjie Xu
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009, China
| | - Xiaoxia Yang
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009, China
| | - Xiangjun Chen
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009, China; Institute of Translational Medicine, Zhejiang University School of Medicine, 268 Kaixuan Road, Hangzhou, 310020, China.
| | - Ke Yao
- Eye Center of the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, 310009, China.
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18
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Cataract-causing mutations L45P and Y46D promote γC-crystallin aggregation by disturbing hydrogen bonds network in the second Greek key motif. Int J Biol Macromol 2020; 167:470-478. [PMID: 33278449 DOI: 10.1016/j.ijbiomac.2020.11.158] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/23/2020] [Accepted: 11/23/2020] [Indexed: 02/07/2023]
Abstract
Congenital cataracts caused by genetic disorders are the primary cause of child blindness across the globe. In this work, we investigated the underlying molecular mechanism of two mutations, L45P and Y46D of γC-crystallin in two Chinese families causing nuclear congenital cataracts. Spectroscopic experiments were performed to determine structural differences between the wild-type (WT) and the L45P or Y46D mutant of γC-crystallin, and the structural stabilities of the WT and mutant proteins were measured under environmental stress (ultraviolet irradiation, pH disorders, oxidative stress, or chemical denaturation). The L45P and Y46D mutants had lower protein solubility and more hydrophobic residues exposed, making them prone to aggregation under environmental stress. The dynamic molecular simulation revealed that the L45P and Y46D mutations destabilized γC-crystallin by altering the hydrogen bonds network around the Trp residues in the second Greek key motif. In summary, L45P and Y46D mutants of γC-crystallin caused more hydrophobic residues to be solvent-exposed, lowered the solubility of γC-crystallin, and increased aggregation propensity under environmental stress. These might be the pathogenesis of γC-crystallin L45P and Y46D mutants related to congenital cataract.
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19
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Xu J, Wang H, Wang A, Xu J, Fu C, Jia Z, Yao K, Chen X. βB2 W151R mutant is prone to degradation, aggregation and exposes the hydrophobic side chains in the fourth Greek Key motif. Biochim Biophys Acta Mol Basis Dis 2020; 1867:166018. [PMID: 33246011 DOI: 10.1016/j.bbadis.2020.166018] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 11/14/2020] [Accepted: 11/16/2020] [Indexed: 12/16/2022]
Abstract
Studies have established that congenital cataract is the major cause of blindness in children across the globe. The β-crystallin protein family is the richest and most soluble structural protein in the lens. Their solubility and stability are essential in maintaining lens transparency. In this study, we identified a novel βB2 mutation W151R in a rare progressive cortical congenital cataract family and explored its pathogenesis using purified protein and mutant related cataract-cell models. Due to its low solubility and poor structural stability, the βB2 W151R mutation was prone to aggregation. Moreover, the W151R mutation enhanced the exposure of the hydrophobic side chains in the fourth Greek Key motif, which were readily degraded by trypsin. However, upon the administration of lanosterol, the negative effect of the W151R mutation was reversed. Therefore, lanosterol is a potential therapeutic option for cataracts.
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Affiliation(s)
- Jingjie Xu
- Eye Center of the Second Affiliated Hospital, Medical College of Zhejiang University, 88 Jiefang Road, Hangzhou 310009, China
| | - Huaxia Wang
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou 310020, China
| | - Ailing Wang
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou 310020, China
| | - Jia Xu
- Eye Center of the Second Affiliated Hospital, Medical College of Zhejiang University, 88 Jiefang Road, Hangzhou 310009, China
| | - Chenxi Fu
- Eye Center of the Second Affiliated Hospital, Medical College of Zhejiang University, 88 Jiefang Road, Hangzhou 310009, China
| | - Zhekun Jia
- Eye Center of the Second Affiliated Hospital, Medical College of Zhejiang University, 88 Jiefang Road, Hangzhou 310009, China
| | - Ke Yao
- Eye Center of the Second Affiliated Hospital, Medical College of Zhejiang University, 88 Jiefang Road, Hangzhou 310009, China.
| | - Xiangjun Chen
- Eye Center of the Second Affiliated Hospital, Medical College of Zhejiang University, 88 Jiefang Road, Hangzhou 310009, China; Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou 310020, China.
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20
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Bari KJ, Sharma S. A Perspective on Biophysical Studies of Crystallin Aggregation and Implications for Cataract Formation. J Phys Chem B 2020; 124:11041-11054. [PMID: 33297682 DOI: 10.1021/acs.jpcb.0c07449] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Lens crystallins are subject to various types of damage during their lifetime which triggers protein misfolding and aggregation, ultimately causing cataracts. There are several models for crystallin aggregation, but a comprehensive picture of the mechanism of cataract is still underway. The complex biomolecular interactions underlying crystallin aggregation have motivated major efforts to resolve the structural details and mechanism of aggregation using multiple biophysical techniques at different resolutions. Together, experimental and computational approaches identify and characterize both amyloidogenic and amorphous aggregates leading to an improved understanding of crystallin aggregation. A rigorous characterization of the aggregation-prone intermediates is crucial in cataract-mediated drug discovery. This Perspective summarizes recent biophysical studies on lens crystallin aggregation. We evaluate the outstanding challenges, future outlook, and rewards in this fertile field of research. With lessons learned from protein folding and multiple pathways of aggregation, we highlight the differences in the overall mechanisms of age-related and congenital cataracts. We expect that a correlation between the existing and developing biophysical techniques would provide a platform to study amyloid architecture in the eye lens and reduce the existing gaps in our understanding of crystallin biophysics.
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Affiliation(s)
- Khandekar Jishan Bari
- Center for Interdisciplinary Sciences, Tata Institute of Fundamental Research, Gopanpally, Hyderabad 500107, India.,Department of Chemical Sciences, Indian Institute of Science Education and Research, Berhampur, Odisha 760010, India
| | - Shrikant Sharma
- Center for Interdisciplinary Sciences, Tata Institute of Fundamental Research, Gopanpally, Hyderabad 500107, India.,Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
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21
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Hu LD, Wang J, Chen XJ, Yan YB. Lanosterol modulates proteostasis via dissolving cytosolic sequestosomes/aggresome-like induced structures. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118617. [DOI: 10.1016/j.bbamcr.2019.118617] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 11/17/2019] [Accepted: 11/25/2019] [Indexed: 01/06/2023]
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22
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Molecular genetics of congenital cataracts. Exp Eye Res 2019; 191:107872. [PMID: 31770519 DOI: 10.1016/j.exer.2019.107872] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 11/12/2019] [Accepted: 11/13/2019] [Indexed: 12/18/2022]
Abstract
Congenital cataracts, the most common cause of visual impairment and blindness in children worldwide, have diverse etiologies. According to statistics analysis, about one quarter of congenital cataracts caused by genetic defects. Various mutations of more than one hundred genes have been identified in hereditary cataracts so far. In this review, we briefly summarize recent developments about the genetics, molecular mechanisms, and treatments of congenital cataracts. The studies of these pathogenic mutations and molecular genetics is making it possible for us to comprehend the underlying mechanisms of cataractogenesis and providing new insights into the preventive, diagnostic and therapeutic approaches of cataracts.
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23
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Jin A, Zhang Y, Xiao D, Xiang M, Jin K, Zeng M. A Novel Mutation p.S93R in CRYBB1 Associated with Dominant Congenital Cataract and Microphthalmia. Curr Eye Res 2019; 45:483-489. [PMID: 31566446 DOI: 10.1080/02713683.2019.1675176] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Purpose: To identify the pathogenetic mutations in a four-generation Chinese family with dominant congenital cataracts and microphthalmia.Methods: A four-generation Chinese family with dominant congenital cataracts were recruited. Genomic DNAs were collected from their peripheral blood leukocytes and subjected to whole exome sequencing. The genetic mutations were identified by bioinformatic analyses and verified by Sanger sequencing.Results: Whole exome sequencing revealed a c.279C>G point mutation in the CRYBB1 gene which was further verified by Sanger sequencing. The nucleotide replacement results in a novel mutation p.S93R in a conserved residue of βB1 crystallin which is predicted to disrupt normal βB1 structure and function.Conclusions: We identified a novel missense mutation p.S93R in CRYBB1 in a Chinese family with autosomal dominant congenital cataracts and microphthalmia. This serine residue is extremely conserved evolutionarily in more than 50 βγ-crystallins of many species. These data will be very helpful to further understand the structural and functional features of crystallins.
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Affiliation(s)
- Aixia Jin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Yu Zhang
- Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Dongchang Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Mengqing Xiang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Kangxin Jin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Mingbing Zeng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.,Hainan Eye Hospital, Hainan Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Haikou, China
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24
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Failure of Oxysterols Such as Lanosterol to Restore Lens Clarity from Cataracts. Sci Rep 2019; 9:8459. [PMID: 31186457 PMCID: PMC6560215 DOI: 10.1038/s41598-019-44676-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 05/01/2019] [Indexed: 01/13/2023] Open
Abstract
The paradigm that cataracts are irreversible and that vision from cataracts can only be restored through surgery has recently been challenged by reports that oxysterols such as lanosterol and 25-hydroxycholesterol can restore vision by binding to αB-crystallin chaperone protein to dissolve or disaggregate lenticular opacities. To confirm this premise, in vitro rat lens studies along with human lens protein solubilization studies were conducted. Cataracts were induced in viable rat lenses cultured for 48 hours in TC-199 bicarbonate media through physical trauma, 10 mM ouabain as Na+/K+ ATPase ion transport inhibitor, or 1 mM of an experimental compound that induces water influx into the lens. Subsequent 48-hour incubation with 15 mM of lanosterol liposomes failed to either reverse these lens opacities or prevent the further progression of cataracts to the nuclear stage. Similarly, 3-day incubation of 47-year old human lenses in media containing 0.20 mM lanosterol or 60-year-old human lenses in 0.25 and 0.50 mM 25-hydroxycholesterol failed to increase the levels of soluble lens proteins or decrease the levels of insoluble lens proteins. These binding studies were followed up with in silico binding studies of lanosterol, 25-hydroxycholesterol, and ATP as a control to two wild type (2WJ7 and 2KLR) and one R120G mutant (2Y1Z) αB-crystallins using standard MOETM (Molecular Operating Environment) and Schrödinger's Maestro software. Results confirmed that compared to ATP, both oxysterols failed to reach the acceptable threshold binding scores for good predictive binding to the αB-crystallins. In summary, all three studies failed to provide evidence that lanosterol or 25-hydroxycholesterol have either anti-cataractogenic activity or bind aggregated lens protein to dissolve cataracts.
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25
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Zhang K, Zhao WJ, Yao K, Yan YB. Dissimilarity in the Contributions of the N-Terminal Domain Hydrophobic Core to the Structural Stability of Lens β/γ-Crystallins. Biochemistry 2019; 58:2499-2508. [PMID: 31037943 DOI: 10.1021/acs.biochem.8b01164] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Vertebrate lens β/γ-crystallins share a conserved tertiary structure consisting of four Greek-key motifs divided into two globular domains. Numerous inherited mutations in β/γ-crystallins have been linked to cataractogenesis. In this research, the folding mechanism underlying cataracts caused by the I21N mutation in βB2 was investigated by comparing the effect of mutagenesis on the structural features and stability of four β/γ-crystallins, βB1, βB2, γC, and γD. Our results showed that the four β/γ-crystallins differ greatly in solubility and stability against various stresses. The I21N mutation greatly impaired βB2 solubility and native structure as well as its stability against denaturation induced by guanidine hydrochloride, heat treatment, and ultraviolet irradiation. However, the deleterious effects were much weaker for mutations at the corresponding sites in βB1, γC, and γD. Molecular dynamics simulations indicated that the introduction of a nonnative hydrogen bond contributed to twisting Greek-key motif I outward, which might direct the misfolding of the I21N mutant of βB2. Meanwhile, partial hydration of the hydrophobic interior of the domain induced by the mutation destabilized βB1, γC, and γD. Our findings highlight the importance of nonnative hydrogen bond formation and hydrophobic core hydration in crystallin misfolding caused by inherited mutations.
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Affiliation(s)
- Kai Zhang
- Eye Center of the Second Affiliated Hospital, School of Medicine , Zhejiang University , Hangzhou 310009 , China
| | - Wei-Jie Zhao
- State Key Laboratory of Membrane Biology, School of Life Sciences , Tsinghua University , Beijing 100084 , China
| | - Ke Yao
- Eye Center of the Second Affiliated Hospital, School of Medicine , Zhejiang University , Hangzhou 310009 , China
| | - Yong-Bin Yan
- State Key Laboratory of Membrane Biology, School of Life Sciences , Tsinghua University , Beijing 100084 , China
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26
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Sun M, Chen C, Hou S, Li X, Wang H, Zhou J, Chen X, Liu P, Kijlstra A, Lin S, Ye J. A novel mutation of PANK4 causes autosomal dominant congenital posterior cataract. Hum Mutat 2019; 40:380-391. [PMID: 30585370 DOI: 10.1002/humu.23696] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 11/27/2018] [Accepted: 12/09/2018] [Indexed: 01/19/2023]
Abstract
Though many mutations have been identified to be associated with the occurrence of congenital cataract, pathogenic loci in some affected families are still unknown. Clinical data and genomic DNA were collected from a four-generation Chinese family. Candidate mutations were independently verified for cosegregation in the whole pedigree. Linkage analysis showed that the disease-causing mutation was located between 1p36.21 and 1p36.33. Analysis of the whole-exome sequencing data combined with linkage analysis identified a novel pathogenic variant (g.2451906C>T) at intron 4 of Pantothenate kinase 4 (PANK4 protein, PANK4 gene) in 1p36.32|606162. This variant showed complete cosegregation with the phenotype in the pedigree. The mutation was not detected in 106 normal controls nor in 40 sporadic congenital cataract patients. The mutation was demonstrated to significantly reduce the expression of the PANK4 protein level in the blood of cataract patients than that in normal individuals by ELISA. Pank4-/- mice showed a cataract phenotype with increased numbers of apoptotic lens epithelial cells, fiber cell aggregation, and significant mRNA variation of crystallin family members. Thus, the association of a new entity of an autosomal dominant cataract with mutations in PANK4, which influences cell proliferation, apoptosis of lens epithelial cells, crystallin abnormalities, and fiber cell derangement, subsequently induces cataract.
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Affiliation(s)
- Min Sun
- Department of Ophthalmology, Research Institute of Surgery and Daping Hospital, Army Medical University, Chongqing, China
| | - Chunlin Chen
- Department of Ophthalmology, Research Institute of Surgery and Daping Hospital, Army Medical University, Chongqing, China
| | - Shengping Hou
- The First Affiliated Hospital, Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing, China
| | - Xue Li
- Department of Ophthalmology, Research Institute of Surgery and Daping Hospital, Army Medical University, Chongqing, China
| | | | - Jiaxing Zhou
- Department of Ophthalmology, Research Institute of Surgery and Daping Hospital, Army Medical University, Chongqing, China
| | - Xi Chen
- Department of Ophthalmology, Research Institute of Surgery and Daping Hospital, Army Medical University, Chongqing, China
| | - Pei Liu
- Department of Ophthalmology, Research Institute of Surgery and Daping Hospital, Army Medical University, Chongqing, China
| | - Aize Kijlstra
- University Eye Clinic Maastricht, Maastricht, the Netherlands
| | - Sen Lin
- Department of Ophthalmology, Research Institute of Surgery and Daping Hospital, Army Medical University, Chongqing, China
| | - Jian Ye
- Department of Ophthalmology, Research Institute of Surgery and Daping Hospital, Army Medical University, Chongqing, China
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27
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Lanosterol and 25-hydroxycholesterol dissociate crystallin aggregates isolated from cataractous human lens via different mechanisms. Biochem Biophys Res Commun 2018; 506:868-873. [PMID: 30392915 DOI: 10.1016/j.bbrc.2018.10.175] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 10/28/2018] [Indexed: 12/14/2022]
Abstract
Cataract, a crystallin aggregation disease, is the leading cause of human blindness worldwide. Surgery is the only established treatment of cataracts and no anti-cataract drugs are available thus far. Recently lanosterol and 25-hydroxycholesterol have been reported to redissolve crystallin aggregates and partially restore lens transparency in animals. However, the efficacies of these two compounds have not been quantitatively studied ex vivo using patient tissues. In this research, we developed a quantitative assay applicable to efficacy validations and mechanistic studies by a protocol to isolate protein aggregates from the surgically removed cataractous human lens. Our results showed that both compounds were effective for human cataractous samples with EC50 values at ten micromolar level. The efficacies of both compounds strongly depended on cataract severity. Lanosterol and 25-hydroxycholesterol were two mechanistically different lead compounds of anti-cataract drug design.
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28
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Zhu S, Xi XB, Duan TL, Zhai Y, Li J, Yan YB, Yao K. The cataract-causing mutation G75V promotes γS-crystallin aggregation by modifying and destabilizing the native structure. Int J Biol Macromol 2018; 117:807-814. [DOI: 10.1016/j.ijbiomac.2018.05.220] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/25/2018] [Accepted: 05/29/2018] [Indexed: 12/31/2022]
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29
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Xu J, Zhao WJ, Chen XJ, Yao K, Yan YB. Introduction of an extra tryptophan fluorophore by cataract-associating mutations destabilizes βB2-crystallin and promotes aggregation. Biochem Biophys Res Commun 2018; 504:851-856. [DOI: 10.1016/j.bbrc.2018.09.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Accepted: 09/06/2018] [Indexed: 12/18/2022]
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30
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Zhao WJ, Yan YB. Increasing susceptibility to oxidative stress by cataract-causing crystallin mutations. Int J Biol Macromol 2018; 108:665-673. [DOI: 10.1016/j.ijbiomac.2017.12.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 12/01/2017] [Accepted: 12/04/2017] [Indexed: 11/24/2022]
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31
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Abstract
Jessica Lacoste from the Donnelly Centre at the University of Toronto was awarded best poster at the annual Society of Biomolecular Imaging and Informatics meeting held in San Diego, September 2017. Her work focuses on characterizing the protein localization of variants involved in rare disease. The current works and future directions of research in rare disease are summarized in the following overview.
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Affiliation(s)
- Jessica Lacoste
- Terrence Donnelly Centre for Cellular and Biomolecular Research , Toronto, Canada .,Department of Molecular Genetics, University of Toronto , Toronto, Canada
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32
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E3 ligase UHRF2 stabilizes the acetyltransferase TIP60 and regulates H3K9ac and H3K14ac via RING finger domain. Protein Cell 2016; 8:202-218. [PMID: 27743347 PMCID: PMC5326618 DOI: 10.1007/s13238-016-0324-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Accepted: 08/31/2016] [Indexed: 11/03/2022] Open
Abstract
UHRF2 is a ubiquitin-protein ligase E3 that regulates cell cycle, genomic stability and epigenetics. We conducted a co-immunoprecipitation assay and found that TIP60 and HDAC1 interact with UHRF2. We previously demonstrated that UHRF2 regulated H3K9ac and H3K14ac differentially in normal and cancer cells. However, the accurate signal transduction mechanisms were not clear. In this study, we found that TIP60 acted downstream of UHRF2 to regulate H3K9ac and H3K14ac expression. TIP60 is stabilized in normal cells by UHRF2 ubiquitination. However, TIP60 is destabilized in cancer cells. Depletion or inhibition of TIP60 disrupts the regulatory relationship between UHRF2, H3K9ac and H3K14ac. In summary, the findings suggest that UHRF2 mediated the post-translational modification of histones and the initiation and progression of cancer.
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