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Yang X, Zhao Z, Wang C, Wang W, Zhang L. Four mutations identified in Chinese families with autosomal dominant congenital cataracts by next-generation sequencing. Genes Genomics 2024; 46:917-925. [PMID: 38869770 DOI: 10.1007/s13258-024-01525-7] [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: 12/24/2023] [Accepted: 05/17/2024] [Indexed: 06/14/2024]
Abstract
BACKGROUND Congenital cataracts, which can arise due to a combination of factors like environmental influences and genetic predisposition, significantly impact children's visual health globally. The occurrence rate of congenital cataracts varies from 0. 63 to 9.74 per 10,000 births. There are 7.4 instances per 10,000 children, with the highest occurrence seen in Asia. Symptoms of the disease include clouding of the lens and visual impairment. Timely identification of the condition plays a crucial role in the management and outlook of pediatric patients. OBJECTIVE This investigation aimed to discover causative mutations in four separate Chinese family lineages. METHODS The detailed clinical data and family history of four Chinese families with autosomal dominant congenital cataracts were carefully documented. Examination of the Whole Exome Sequencing was utilized to identify the genetic anomalies present in the familial cases. Subsequent validation of the identified mutations was carried out using PCR and Sanger sequencing. Following this, various computational predictive programs were utilized to evaluate how the mutations impact the structure and function of the protein. RESULTS The sequencing results reveal four potential disease-causing mutations: c.436G > A (p.V146M) of CRYBB2 Family 1, c.26G > T (p.R9I) of GJA3 in family 2, c.227G > A (p.R76H) of GJA8 in family 3, c.-168G > T of FTL in family 4. Among them, the causative mutation in Family GJA3 is novel, and Family FTL is a rare cataract syndrome. These familial mutations showed complete co-segregation with the affected individuals, with no presence in unaffected family members or the 100 controls. Several bioinformatic prediction tools also support the likely pathogenicity of these mutations. CONCLUSION Our findings expand the mutational and phenotypic spectrum of genes associated with congenital cataracts and provide clues to the pathogenesis of congenital cataracts. These data also demonstrate the importance of NGS technology for the molecular diagnosis of congenital cataract patients.
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Affiliation(s)
- Xinyi Yang
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin, 150000, China
| | - Zitong Zhao
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin, 150000, China
| | - Chun Wang
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin, 150000, China
| | - Wenxuan Wang
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin, 150000, China
| | - Lu Zhang
- Eye Hospital, The First Affiliated Hospital of Harbin Medical University, Harbin, 150000, China.
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Sun J, Morishima K, Inoue R, Sugiyama M, Takata T. Characterization of βB2-crystallin tryptophan mutants reveals two different folding states in solution. Protein Sci 2024; 33:e5092. [PMID: 38924206 PMCID: PMC11201810 DOI: 10.1002/pro.5092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2024] [Revised: 06/07/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024]
Abstract
Conserved tryptophan residues are critical for the structure and the stability of β/γ-crystallin in the lenses of vertebrates. During aging, in which the lenses are continuously exposed to ultraviolet irradiation and other environmental stresses, oxidation of tryptophan residues in β/γ-crystallin is triggered and impacts the lens proteins to varying degrees. Kynurenine derivatives, formed by oxidation of tryptophan, accumulate, resulting in destabilization and insolubilization of β/γ-crystallin, which correlates with age-related cataract formation. To understand the contribution of tryptophan modification on the structure and stability of human βB2-crystallin, five tryptophan residues were mutated to phenylalanine considering its similarity in structure and hydrophilicity to kynurenine. Among all mutants, W59F and W151F altered the stability and homo-oligomerization of βB2-crystallin-W59F promoted tetramerization whereas W151F blocked oligomerization. Most W59F dimers transformed into tetramer in a month, and the separated dimer and tetramer of W59F demonstrated different structures and hydrophobicity, implying that the biochemical properties of βB2-crystallin vary over time. By using SAXS, we found that the dimer of βB2-crystallin in solution resembled the lattice βB1-crystallin dimer (face-en-face), whereas the tetramer of βB2-crystallin in solution resembled its lattice tetramer (domain-swapped). Our results suggest that homo-oligomerization of βB2-crystallin includes potential inter-subunit reactions, such as dissociation, unfolding, and re-formation of the dimers into a tetramer in solution. The W>F mutants are useful in studying different folding states of βB2-crystallin in lens.
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Affiliation(s)
- Jiayue Sun
- Department of Chemistry, Graduate School of ScienceKyoto UniversityKyotoJapan
| | - Ken Morishima
- Institute for Integrated Radiation and Nuclear ScienceKyoto UniversityOsakaJapan
| | - Rintaro Inoue
- Institute for Integrated Radiation and Nuclear ScienceKyoto UniversityOsakaJapan
| | - Masaaki Sugiyama
- Institute for Integrated Radiation and Nuclear ScienceKyoto UniversityOsakaJapan
| | - Takumi Takata
- Institute for Integrated Radiation and Nuclear ScienceKyoto UniversityOsakaJapan
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Blue EE, Moore KJ, North KE, Desrosiers TA, Carmichael SL, White JJ, Chong JX, Bamshad MJ, Jenkins MM, Almli LM, Brody LC, Freedman SF, Reefhuis J, Romitti PA, Shaw GM, Werler M, Kay DM, Browne ML, Feldkamp ML, Finnell RH, Nembhard WN, Pangilinan F, Olshan AF. Exome sequencing identifies novel genes underlying primary congenital glaucoma in the National Birth Defects Prevention Study. Birth Defects Res 2024; 116:e2384. [PMID: 38990107 PMCID: PMC11245170 DOI: 10.1002/bdr2.2384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 06/07/2024] [Accepted: 06/25/2024] [Indexed: 07/12/2024]
Abstract
BACKGROUND Primary congenital glaucoma (PCG) affects approximately 1 in 10,000 live born infants in the United States (U.S.). PCG has a autosomal recessive inheritance pattern, and variable expressivity and reduced penetrance have been reported. Likely causal variants in the most commonly mutated gene, CYP1B1, are less prevalent in the U.S., suggesting that alternative genes may contribute to the condition. This study utilized exome sequencing to investigate the genetic architecture of PCG in the U.S. and to identify novel genes and variants. METHODS We studied 37 family trios where infants had PCG and were part of the National Birth Defects Prevention Study (births 1997-2011), a U.S. multicenter study of birth defects. Samples underwent exome sequencing and sequence reads were aligned to the human reference sample (NCBI build 37/hg19). Variant filtration was conducted under de novo and Mendelian inheritance models using GEMINI. RESULTS Among candidate variants, CYP1B1 was most represented (five trios, 13.5%). Twelve probands (32%) had potentially pathogenic variants in other genes not previously linked to PCG but important in eye development and/or to underlie Mendelian conditions with potential phenotypic overlap (e.g., CRYBB2, RXRA, GLI2). CONCLUSION Variation in the genes identified in this population-based study may help to further explain the genetics of PCG.
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Affiliation(s)
- Elizabeth E Blue
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, Washington, USA
- Brotman-Baty Institute for Precision Medicine, Seattle, Washington, USA
| | - Kristin J Moore
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Kari E North
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Tania A Desrosiers
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Suzan L Carmichael
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA
| | - Janson J White
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Jessica X Chong
- Brotman-Baty Institute for Precision Medicine, Seattle, Washington, USA
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Michael J Bamshad
- Brotman-Baty Institute for Precision Medicine, Seattle, Washington, USA
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington, USA
- Division of Genetic Medicine, Seattle Children's Hospital, Seattle, Washington, USA
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, Washington, USA
| | - Mary M Jenkins
- National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Lynn M Almli
- National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Lawrence C Brody
- Division of Genomics and Society, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Sharon F Freedman
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, USA
| | - Jennita Reefhuis
- National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Paul A Romitti
- Department of Epidemiology, College of Public Health, The University of Iowa, Iowa City, Iowa, USA
| | - Gary M Shaw
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA
| | - Martha Werler
- Department of Epidemiology, School of Public Health, Boston University, Boston, Massachusetts, USA
- Slone Epidemiology Center at Boston University, Boston, Massachusetts, USA
| | - Denise M Kay
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Marilyn L Browne
- New York State Department of Health, Birth Defects Registry, Albany, New York, USA
- Department of Epidemiology and Biostatistics, University at Albany School of Public Health, Rensselaer, New York, USA
| | - Marcia L Feldkamp
- Division of Medical Genetics, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Richard H Finnell
- Center for Precision Environmental Health, Departments of Molecular and Cellular Biology and Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Wendy N Nembhard
- Department of Epidemiology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Faith Pangilinan
- Division of Genomics and Society, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Andrew F Olshan
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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Shu X, Liu Y, He F, Gong Y, Li J. A bibliometric and visualized analysis of the pathogenesis of cataracts from 1999 to 2023. Heliyon 2024; 10:e26044. [PMID: 38390089 PMCID: PMC10881887 DOI: 10.1016/j.heliyon.2024.e26044] [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: 07/17/2023] [Revised: 02/01/2024] [Accepted: 02/07/2024] [Indexed: 02/24/2024] Open
Abstract
Research on the pathogenesis of cataracts is ongoing and the number of publications on this topic is increasing annually. This study offers an overview of the research status, popular topics, and scholarly tendencies in the field of cataract pathogenesis over recent decades,which helps to guide future research directions, and optimize resource allocation. In the present study, we performed a bibliometric analysis of cataract pathogenesis. Publications from January 1, 1999, to December 20, 2023, were collected from the Web of Science Core Collection (WoSCC), and the extracted data were quantified and analyzed. We analyzed and presented the data using Microsoft Excel, VOSviewer, CiteSpace, and Python. In all, 4006 articles were evaluated based on various characteristics, including publication year, authors, countries, institutions, journals, citations, and keywords. This study utilized VOSviewer to conduct visualized analysis, including co-authorship, co-citation, co-occurrence, and network visualization. The CiteSpace software was used to identify keywords with significant bursts of activity. The number of annual global publications climbed from 76 to 277 between 1999 and 2023, a 264.47% rise. Experimental Eye Research published the most manuscripts (178 publications), whereas Investigative Ophthalmology & Visual Science received the most citations (6675 citations). The most influential and productive country, institution, and author were the United States (1244 publications, 54,456 citations), University of California system (136 publications, 5401 citations), and Yao Ke (49 publications, 838 citations), respectively. The top 100 ranked keywords are divided into four clusters through co-occurrence analysis: (1) secondary cataracts, (2) oxidative stress, (3) gene mutations and protein abnormalities, and (4) alteration of biological processes in lens epithelial cells. Further discussions on the four subtopics outline the research topics and trends. In conclusion, the specific mechanism of cataract formation remains a popular topic for future research and should be explored in greater depth.
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Affiliation(s)
- Xinjie Shu
- Department of Ophthalmology, Medical Sciences Research Center, University-Town Hospital of Chongqing Medical University, No. 55, University Town Central Road, Shapingba District, Chongqing, 401331, People's Republic of China
| | - Yingying Liu
- Department of Ophthalmology, Medical Sciences Research Center, University-Town Hospital of Chongqing Medical University, No. 55, University Town Central Road, Shapingba District, Chongqing, 401331, People's Republic of China
| | - Fanfan He
- Department of Ophthalmology, Medical Sciences Research Center, University-Town Hospital of Chongqing Medical University, No. 55, University Town Central Road, Shapingba District, Chongqing, 401331, People's Republic of China
| | - Yu Gong
- Department of Ophthalmology, Medical Sciences Research Center, University-Town Hospital of Chongqing Medical University, No. 55, University Town Central Road, Shapingba District, Chongqing, 401331, People's Republic of China
| | - Jiawen Li
- Department of Ophthalmology, Medical Sciences Research Center, University-Town Hospital of Chongqing Medical University, No. 55, University Town Central Road, Shapingba District, Chongqing, 401331, People's Republic of China
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Delas F, Koller S, Feil S, Dacheva I, Gerth-Kahlert C, Berger W. Novel CRYGC Mutation in Conserved Ultraviolet-Protective Tryptophan (p.Trp131Arg) Is Linked to Autosomal Dominant Congenital Cataract. Int J Mol Sci 2023; 24:16594. [PMID: 38068917 PMCID: PMC10706789 DOI: 10.3390/ijms242316594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 10/13/2023] [Accepted: 11/14/2023] [Indexed: 12/18/2023] Open
Abstract
Congenital cataract (CC), the most prevalent cause of childhood blindness and amblyopia, necessitates prompt and precise genetic diagnosis. The objective of this study is to identify the underlying genetic cause in a Swiss patient with isolated CC. Whole exome sequencing (WES) and copy number variation (CNV) analysis were conducted for variant identification in a patient born with a total binocular CC without a family history of CC. Sanger Sequencing was used to confirm the variant and segregation analysis was used to screen the non-affected parents. The first de novo missense mutation at c.391T>C was identified in exon 3 of CRYGC on chromosome 2 causing the substitution of a highly conserved Tryptophan to an Arginine located at p.Trp131Arg. Previous studies exhibit significant changes in the tertiary structure of the crystallin family in the following variant locus, making CRYGC prone to aggregation aggravated by photodamage resulting in cataract. The variant can be classified as pathogenic according to the American College of Medical Genetics and Genomics (ACMG) criteria (PP3 + PM1 + PM2 + PS2; scoring 10 points). The identification of this novel variant expands the existing knowledge on the range of variants found in the CRYGC gene and contributes to a better comprehension of cataract heterogeneity.
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Affiliation(s)
- Flora Delas
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (F.D.); (S.K.); (S.F.)
| | - Samuel Koller
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (F.D.); (S.K.); (S.F.)
| | - Silke Feil
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (F.D.); (S.K.); (S.F.)
| | - Ivanka Dacheva
- Department of Ophthalmology, Cantonal Hospital of St. Gallen, 9007 St. Gallen, Switzerland;
| | | | - Wolfgang Berger
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (F.D.); (S.K.); (S.F.)
- Neuroscience Center Zürich (ZNZ), University of Zurich and ETH Zurich, 8006 Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8006 Zurich, Switzerland
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Xu J, Zhang Y, Liu J, Hu L, Luo C, Yao K, Chen X. Heteromeric formation with βA3 protects the low thermal stability of βB1-L116P. Br J Ophthalmol 2023; 107:1936-1942. [PMID: 36126102 DOI: 10.1136/bjo-2022-322247] [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: 07/16/2022] [Accepted: 08/22/2022] [Indexed: 11/04/2022]
Abstract
BACKGROUND/AIMS Congenital cataract is the leading cause of visual disability and blindness in childhood. βB1-crystallin (CRYBB1) comprises about 1/10th of crystallin structural proteins, forming heteromers to maintain lens transparency. We previously reported a CRYBB1 mutation (c.347T>C, p.L116P) affecting 16 patients in a congenital nuclear cataract family. In this study, we investigate the underlying pathogenic mechanism of βB1-L116P. METHODS Protein isolation, size-exclusion chromatography, spectroscopy, Uncle stability screens and molecular dynamics simulations were used to assess βA3- and βB1-crystallin thermal stability, structural properties and heteromer formation. RESULTS Cells that overexpressed βB1-L116P tended to form aggregates and precipitations under heat-shock stress. Thermal denaturation and time-dependent turbidity experiments showed that thermal stability was significantly impaired. Moreover, protein instability appeared to increase with elevated concentrations detected by the Uncle system. Additionally, βA3 had a relative protective effect on βB1-L116P after heteromers were formed, although βA3 was relatively unstable and was usually protected by basic β-crystallins. Molecular dynamic simulations revealed that L116P mutation altered the hydrophobic residues at the surface around the mutant site, providing solvents more access to the internal and hydrophobic parts of the protein. CONCLUSIONS Decreased βB1-crystallin thermal stability in the presence of the cataract-related L116P mutation contributes significantly to congenital cataract formation. Moreover, its formation of heteromers with βA3 protects against the low thermal stability of βB1-L116P.
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Affiliation(s)
- Jingjie Xu
- Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Ying Zhang
- Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Jian Liu
- Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- National Clinical Research Center for Child Health, Hangzhou, Zhejiang Province, China
| | - Lidan Hu
- Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- National Clinical Research Center for Child Health, Hangzhou, Zhejiang Province, China
| | - Chenqi Luo
- Eye Center, Second Hospital Affiliated to Medical College of Zhejiang University, Hangzhou, Zhejiang, China
| | - Ke Yao
- Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xiangjun Chen
- Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- National Clinical Research Center for Child Health, Hangzhou, Zhejiang Province, China
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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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Luo C, Xu J, Fu C, Yao K, Chen X. New insights into change of lens proteins' stability with ageing under physiological conditions. Br J Ophthalmol 2023; 107:442-446. [PMID: 34593413 DOI: 10.1136/bjophthalmol-2021-319834] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 09/12/2021] [Indexed: 11/03/2022]
Abstract
BACKGROUND Age-related cataract, which presents as a cloudy lens, is the primary cause of vision impairment worldwide and can cause more than 80% senile blindness. Previous studies mainly explored the profile of lens proteins at a low concentration because of technical limitations, which could not reflect physiological status. This study focuses on protein stability changes with ageing under physiological conditions using a novel equipment, Unchained Labs (Uncle), to evaluate protein thermal stability. METHODS Samples were assessed through Unchained Labs, size-exclusion chromatography, western blot and biophysics approaches including the Thioflavin T, ultraviolet and internal fluorescence. RESULTS With age, the melting temperature value shifted from 67.8°C in the young group to 64.2°C in the aged group. Meanwhile, crystallin may form more isomeric oligomers and easy to be degraded in aged lenses. The spectroscopic and size-exclusion chromatography results show a higher solubility after administrated with lanosterol under the environmental stress. CONCLUSION We are the first to explore rabbit lens protein stability changes with ageing using biophysical methods under physiological conditions, and this study can conclude that the structural stability and solubility of lens proteins decrease with ageing. Additionally, lanosterol could aid in resolving protein aggregation, making it a potential therapeutic option for cataracts. So, this study provides cataract models for anti-cataract drug developments.
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Affiliation(s)
- Chenqi Luo
- Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jingjie Xu
- Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Chenxi Fu
- Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ke Yao
- Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiangjun Chen
- Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China .,Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
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9
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Cysteine Pathogenic Variants of PMM2 Are Sensitive to Environmental Stress with Loss of Structural Stability. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2023; 2023:5964723. [PMID: 36743691 PMCID: PMC9891822 DOI: 10.1155/2023/5964723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 08/27/2022] [Accepted: 09/10/2022] [Indexed: 01/26/2023]
Abstract
Congenital disorders of glycosylation (CDG) are severe metabolic disorders caused by an imbalance in the glycosylation pathway. Phosphomannomutase2 (PMM2-CDG), the most prevalent CDG, is mainly due to the disorder of PMM2. Pathogenic variants in cysteine have been found in various diseases, and cysteine residues have a potential as therapeutic targets. PMM2 harbor six cysteines; the variants Cys9Tyr (C9Y) and Cys241Ser (C241S) of PMM2 have been identified to associate with CDG, but the underlying molecular mechanisms remain uncharacterized. Here, we purified PMM2 wild type (WT), C9Y, and C241S to investigate their structural characteristics and biophysical properties by spectroscopic experiments under physiological temperature and environmental stress. Notably, the variants led to drastic changes in the protein properties and were prone to aggregate at physiological temperature. Meanwhile, PMM2 was sensitive to oxidative stress, and the cysteine pathogenic variants led to obvious aggregate formation and a higher cellular apoptosis ratio under oxidative stress. Molecular dynamic simulations indicated that the pathogenic variants changed the core domain of homomeric PMM2 and subunit binding free energy. Moreover, we tested the potential drug targeting PMM2-celastrol in cell level and explained the result by molecular docking simulation. In this study, we delineated the pathological mechanism of the cysteine substitution in PMM2, which addressed the vital role of cysteine in PMM2 and provided novel insights into prevention and treatment strategies for PMM2-CDG.
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Tang Y, Xu J, Lu Y, Zheng T. Three Novel Mutations of Microphthalmos Identified in Two Chinese Families. PHENOMICS (CHAM, SWITZERLAND) 2022; 2:254-260. [PMID: 36939803 PMCID: PMC9590552 DOI: 10.1007/s43657-022-00053-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 03/03/2022] [Accepted: 03/08/2022] [Indexed: 10/18/2022]
Abstract
Genetic alterations are a major cause of microphthalmos, while novel-related genes and mutations in microphthalmos have rarely been explored. To identify the underlying genetic defect responsible for microphthalmos eyes in two three-generation Chinese families, we screened 425 genes involved in common inherited non-syndromic eye diseases with next-generation sequencing-based target capture sequencing of the two probands of two three-generation Chinese families diagnosed with microphthalmos. Variants were filtered and analyzed to identify possible disease-causing variants before Sanger sequencing validation. We enrolled two families with microphthalmos (Family 1: microphthalmos with congenital ocular coloboma and Family 2: simple microphthalmos). Two novel heterozygous mutations, Peroxidasin (PXDN) c.3165C>T (p.Pro1055Pro) and PXDN c.2640C>G (p.Arg880Arg), were found in Family 1, and Crystallin Beta B2 (CRYBB2) c.481G>A (p.Gly161Arg) was found in Family 2, but none of the mutations were found in the unaffected individuals, who were phenotypically normal. Multiple orthologous sequence alignment (MSA) revealed that the CRYBB2 p.Gly161Arg mutation was a deleterious effect mutation. In conclusion, the three novel mutations found in our study extend our current understanding of the genetic basis of microphthalmos and provide early pre-symptomatic diagnosis and emphasize the significance of genetic diagnosis of microphthalmos.
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Affiliation(s)
- Yating Tang
- grid.411079.a0000 0004 1757 8722Department of Ophthalmology and Eye Research Institute, Eye and ENT Hospital of Fudan University, Shanghai, 200031 China
- grid.506261.60000 0001 0706 7839NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Science, Shanghai, 200031, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, 200031 China
| | - Jie Xu
- grid.411079.a0000 0004 1757 8722Department of Ophthalmology and Eye Research Institute, Eye and ENT Hospital of Fudan University, Shanghai, 200031 China
- grid.506261.60000 0001 0706 7839NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Science, Shanghai, 200031, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, 200031 China
| | - Yi Lu
- grid.411079.a0000 0004 1757 8722Department of Ophthalmology and Eye Research Institute, Eye and ENT Hospital of Fudan University, Shanghai, 200031 China
- grid.506261.60000 0001 0706 7839NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Science, Shanghai, 200031, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, 200031 China
| | - Tianyu Zheng
- grid.411079.a0000 0004 1757 8722Department of Ophthalmology and Eye Research Institute, Eye and ENT Hospital of Fudan University, Shanghai, 200031 China
- grid.506261.60000 0001 0706 7839NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Science, Shanghai, 200031, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, 200031 China
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11
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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: 6] [Impact Index Per Article: 3.0] [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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12
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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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13
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Novel Likely Pathogenic Variants Identified by Panel-Based Exome Sequencing in Congenital Cataract Patients. J Ophthalmol 2021; 2021:3847409. [PMID: 34840822 PMCID: PMC8612798 DOI: 10.1155/2021/3847409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 10/02/2021] [Indexed: 11/18/2022] Open
Abstract
Purpose To identify likely pathogenic variants in three families with congenital cataracts via panel-based exome sequencing. Methods A panel containing 153 genes associated with congenital cataracts was designed. Genes were selected through reference to databases including the Human Gene Mutation Database (HGMD), Online Mendelian Inheritance in Man (OMIM), Genetic Home Reference, and the latest peer-reviewed publications on the genetics of hereditary cataracts. Panel-based exome sequencing was performed with the Illumina HiSeq X-Ten platform, and then the identified variants were confirmed with Sanger sequencing and evaluated according to the American College of Medical Genetics and Genomics (ACMG) criteria. Results Three likely pathogenic variants were found. A novel CRYBB2: c.230G > T p.G77V variant was identified in family A, a novel CRYBB2: c.230G > A p.G77D variant was identified in family B, and a novel CRYGD: c.475delG p.A159Pfs∗9 variant was identified in family C. Conclusion Panel-based exome sequencing revealed three likely pathogenic variants in three unrelated Chinese families with congenital cataracts. These data expand the genetic spectrum associated with congenital cataracts.
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14
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Chen D, Zhu S. Whole-exome sequencing identification of a recurrent CRYBB2 variant in a four-generation Chinese family with congenital nuclear cataracts. Exp Ther Med 2021; 22:1375. [PMID: 34650623 PMCID: PMC8506933 DOI: 10.3892/etm.2021.10810] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 08/19/2021] [Indexed: 12/25/2022] Open
Abstract
Congenital cataracts is the most common cause of visual impairment and blindness in children. Although there have been extensive studies into the pathogenesis of congenital cataracts, the pathogenic mechanism underlying the recurrent variant CRYBB2:c.62T>A(p.I21N) has not been previously reported. Thus, the present study aimed to use whole-exome sequencing (WES) to identify potential genetic variants and investigate how they may have induced the occurrence of cataracts in a four-generation Chinese family with congenital nuclear cataracts. The medical history of this family was recorded and WES was conducted for one proband. Sanger sequencing was used to verify the presence of the putative variant in all participants. PolyPhen-2, SIFT and ProtScale were used to analyze the effect of the identified variants on protein function and hydrophobicity, and Pymol was used to show the structure of the wild-type (Wt) and mutant β-crystallin B2 (CRYBB2) protein. Full-length Wt-CRYBB2 or mutant-CRYBB2 (I21N-CRYBB2) were fused to green fluorescent protein (GFP), and the recombinant plasmids were transfected into HeLa cells. Reverse transcription-quantitative PCR and western blotting were used to detect the expression levels of CRYBB2 mRNA and protein. Immunofluorescence and flow cytometry analyses were used to detect protein localization and apoptosis, respectively. A recurrent variant CRYBB2:c.62T>A(p.I21N) was identified in a four-generation Chinese family with congenital nuclear cataracts. Multiple-sequence alignment of CRYBB2 demonstrated that codon 21 was highly conserved. Pymol revealed that the structure of the I21N-CRYBB2 protein was distinct from that of Wt-CRYBB2. PolyPhen-2 predicted that it had a variant provean score 1.0, suggesting it was 'probably damaging', and SIFT predicted it had a variant provean score of -5.113, indicating it was 'deleterious'. ProtScale indicated that the hydrophobicity of the mutation site was significantly reduced. The protein expression levels of the I21N-CRYBB2 were decreased compared with the Wt-CRYBB2. Immunofluorescence analysis revealed that the variant I21N-CRYBB2 protein tended to accumulate around the nucleus, and flow cytometry analysis indicated that it increased cell apoptosis. Furthermore, I21N-CRYBB2 induced the activation of the unfolded protein response (UPR). In conclusion, a pathogenic variant of CRYBB2:c.62T>A(p.I21N) was identified via WES in a four-generation Chinese family with congenital nuclear cataracts. Through biological analysis, it was found that the variant induced abnormal protein aggregation, activated the UPR and triggered excessive cell apoptosis, which may lead to the occurrence of congenital nuclear cataracts in this family.
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Affiliation(s)
- Doudou Chen
- Eye School of Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 610075, P.R. China.,Department of Ophthalmology, Ineye Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 610032, P.R. China.,Key Laboratory of Sichuan Province Ophthalmopathy Prevention & Cure and Visual Function Protection, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 610032, P.R. China
| | - Siquan Zhu
- Eye School of Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 610075, P.R. China.,Department of Ophthalmology, Ineye Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 610032, P.R. China.,Key Laboratory of Sichuan Province Ophthalmopathy Prevention & Cure and Visual Function Protection, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 610032, P.R. China.,Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100006, P.R. China
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15
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Rocha MA, Sprague-Piercy MA, Kwok AO, Roskamp KW, Martin RW. Chemical Properties Determine Solubility and Stability in βγ-Crystallins of the Eye Lens. Chembiochem 2021; 22:1329-1346. [PMID: 33569867 PMCID: PMC8052307 DOI: 10.1002/cbic.202000739] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/17/2020] [Indexed: 11/10/2022]
Abstract
βγ-Crystallins are the primary structural and refractive proteins found in the vertebrate eye lens. Because crystallins are not replaced after early eye development, their solubility and stability must be maintained for a lifetime, which is even more remarkable given the high protein concentration in the lens. Aggregation of crystallins caused by mutations or post-translational modifications can reduce crystallin protein stability and alter intermolecular interactions. Common post-translational modifications that can cause age-related cataracts include deamidation, oxidation, and tryptophan derivatization. Metal ion binding can also trigger reduced crystallin solubility through a variety of mechanisms. Interprotein interactions are critical to maintaining lens transparency: crystallins can undergo domain swapping, disulfide bonding, and liquid-liquid phase separation, all of which can cause opacity depending on the context. Important experimental techniques for assessing crystallin conformation in the absence of a high-resolution structure include dye-binding assays, circular dichroism, fluorescence, light scattering, and transition metal FRET.
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Affiliation(s)
- Megan A. Rocha
- Department of Chemistry, University of California, Irvine, 1102 Natural Sciences 2, Irvine, CA 92697-2025 (USA)
| | - Marc A. Sprague-Piercy
- Department of Molecular Biology and Biochemistry, University of California Irvine, 3205 McGaugh Hall, Irvine, CA 92697-2525
| | - Ashley O. Kwok
- Department of Chemistry, University of California, Irvine, 1102 Natural Sciences 2, Irvine, CA 92697-2025 (USA)
| | - Kyle W. Roskamp
- Department of Chemistry, University of California, Irvine, 1102 Natural Sciences 2, Irvine, CA 92697-2025 (USA)
| | - Rachel W. Martin
- Department of Chemistry, University of California, Irvine, 1102 Natural Sciences 2, Irvine, CA 92697-2025 (USA)
- Department of Molecular Biology and Biochemistry, University of California Irvine, 3205 McGaugh Hall, Irvine, CA 92697-2525
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16
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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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17
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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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18
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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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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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Yang X, Xu J, Fu C, Jia Z, Yao K, Chen X. The cataract-related S39C variant increases γS-crystallin sensitivity to environmental stress by destroying the intermolecular disulfide cross-links. Biochem Biophys Res Commun 2020; 526:459-465. [DOI: 10.1016/j.bbrc.2020.03.072] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 03/11/2020] [Indexed: 02/06/2023]
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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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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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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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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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