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Meng B, Wang K, Huang Y, Wang Y. The G allele of the IGF1 rs2162679 SNP is a potential protective factor for any myopia: Updated systematic review and meta-analysis. PLoS One 2022; 17:e0271809. [PMID: 35862416 PMCID: PMC9302841 DOI: 10.1371/journal.pone.0271809] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 07/07/2022] [Indexed: 12/03/2022] Open
Abstract
Background The insulin-like growth factor 1 (IGF1) gene is located within the myopia-associated MYP3 interval, which suggests it may play an important role in the progression of myopia. However, the association between IGF1 SNPs and any myopia is rarely reported. Methods A comprehensive literature search was conducted on studies published up to July 22, 2021 in PubMed, EMBASE, CBM, COCHRANE, CNKI, WANFANG and VIP databases. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for single-nucleotide polymorphisms (SNPs) that have been evaluated in at least three studies. Results Nine studies involving 4596 subjects with any myopia and 4950 controls examined 25 SNPs in IGF1 gene, among which seven SNPs were included in this meta-analysis. Significant associations were not found in any genetic models between rs6214, rs12423791, rs5742632, rs10860862, rs5742629 and any myopia. Rs2162679 was suggestively associated with any myopia in the codominant model (GA vs. AA: OR = 0.87, 95% CI: 0.76–1.00) and the dominant model (GG+GA vs. AA: OR = 0.88, 95% CI = 0.78–1.00). Conclusion Meta-analysis of updated data reveals that the G allele of the IGF1 rs2162679 SNP is a potential protective factor for any myopia, which is worth further researches.
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Kunceviciene E, Muskieta T, Sriubiene M, Liutkeviciene R, Smalinskiene A, Grabauskyte I, Insodaite R, Juoceviciute D, Kucinskas L. Association of CX36 Protein Encoding Gene GJD2 with Refractive Errors. Genes (Basel) 2022; 13:genes13071166. [PMID: 35885949 PMCID: PMC9319995 DOI: 10.3390/genes13071166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 06/27/2022] [Accepted: 06/27/2022] [Indexed: 02/04/2023] Open
Abstract
Purpose: This study aimed to evaluate the associations of GJD2 (rs634990, rs524952) and RASGRF1 (rs8027411, rs4778879, rs28412916) gene polymorphisms with refractive errors. Methods: The study included 373 subjects with refractive errors (48 myopia, 239 myopia with astigmatism, 14 hyperopia, and 72 hyperopia with astigmatism patients) and 104 ophthalmologically healthy subjects in the control group. A quantitative real-time polymerase chain reaction (qPCR) method was chosen for genotyping. Statistical calculations and analysis of results were performed with IBM SPSS Statistics 27 software. Results: The correlations in monozygotic (MZ) twin pairs were higher compared to DZ pairs, indicating genetic effects on hyperopia and astigmatism. The heritability (h2) of hyperopia and astigmatism was 0.654 for the right eye and 0.492 for the left eye. The GJD2 rs634990 TT genotype increased the incidence of hyperopia with astigmatism by 2.4-fold and the CT genotype decreased the incidence of hyperopia with astigmatism by 0.51-fold (p < 0.05). The GJD2 rs524952 AT genotype reduced the incidence of hyperopia with astigmatism by 0.53-fold (p < 0.05). Haplotype analysis of SNPs in the GJD2 gene revealed two statistically significant haplotypes: ACTAGG for rs634990 and TTTAGA for rs524952, which statistically significantly reduced the incidence of hyperopia and hyperopia with astigmatism by 0.41-fold (95% CI: 0.220−0.765) and 0.383-fold (95% CI: 0.199−0.737), respectively (p < 0.05). It was also found that, in the presence of haplotypes ACTAGG for rs634990 and TATAGA for rs524952, the possibility of hyperopia was reduced by 0.4-fold (p < 0.05). Conclusions: the heritability of hyperopia and hyperopia with astigmatism was 0.654−0.492, according to different eyes in patients between 20 and 40 years. The GJD2 rs634990 was identified as an SNP, which has significant associations with the co-occurrence of hyperopia and astigmatism. Patients with the GJD2 gene rs634990 TT genotype were found to have a 2.4-fold higher risk of develop hyperopia with astigmatism.
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Liu QY, Cui XH, Li Z, Shao Y, Xing DJ, Li WB, Li XR. [Knobloch syndrome: a case report]. [ZHONGHUA YAN KE ZA ZHI] CHINESE JOURNAL OF OPHTHALMOLOGY 2022; 58:457-459. [PMID: 35692029 DOI: 10.3760/cma.j.cn112142-20210618-00296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
A 5-year-old girl came to the Tianjin Medical University Eye Hospital in May 2021 because of her poor eyesight after birth. The physical examination showed that she had high myopia, esotropia, horizontal tremor, and high myopia retinopathy of both eyes. After inquiring about her medical history, we found that the baby's occipital cystic mass swelled after birth, and CT examination showed that the occipital skull plate defect with meningocele, but without treatment, at present, the occipital mass had subsided by itself. Considering the eye manifestations and skull changes of the child, it may be conformed to Knobloch syndrome, after the detection of V4 by full exon gene, it was found that the child had the compound heterozygous variation of pathogenic gene COL18A1, and Knobloch syndrome was definite, Knobloch syndrome is a rare autosomal recessive hereditary disease with typical features of high myopia, retinal detachment and occipital encephalocele. At present, there is no clear treatment plan, and gene therapy may be an effective treatment for Knobloch syndrome in the future.
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Guggenheim JA, Clark R, Cui J, Terry L, Patasova K, Haarman AEG, Musolf AM, Verhoeven VJM, Klaver CCW, Bailey-Wilson JE, Hysi PG, Williams C. Whole exome sequence analysis in 51 624 participants identifies novel genes and variants associated with refractive error and myopia. Hum Mol Genet 2022; 31:1909-1919. [PMID: 35022715 PMCID: PMC9169456 DOI: 10.1093/hmg/ddac004] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 12/31/2021] [Accepted: 01/04/2022] [Indexed: 11/30/2022] Open
Abstract
Refractive errors are associated with a range of pathological conditions, such as myopic maculopathy and glaucoma, and are highly heritable. Studies of missense and putative loss of function (pLOF) variants identified via whole exome sequencing (WES) offer the prospect of directly implicating potentially causative disease genes. We performed a genome-wide association study for refractive error in 51 624 unrelated adults, of European ancestry, aged 40-69 years from the UK and genotyped using WES. After testing 29 179 pLOF and 495 263 missense variants, 1 pLOF and 18 missense variants in 14 distinct genomic regions were taken forward for fine-mapping analysis. This yielded 19 putative causal variants of which 18 had a posterior inclusion probability >0.5. Of the 19 putative causal variants, 12 were novel discoveries. Specific variants were associated with a more myopic refractive error, while others were associated with a more hyperopic refractive error. Association with age of onset of spectacle wear (AOSW) was examined in an independent validation sample (38 100 early AOSW cases and 74 243 controls). Of 11 novel variants that could be tested, 8 (73%) showed evidence of association with AOSW status. This work identified COL4A4 and ATM as novel candidate genes associated with refractive error. In addition, novel putative causal variants were identified in the genes RASGEF1, ARMS2, BMP4, SIX6, GSDMA, GNGT2, ZNF652 and CRX. Despite these successes, the study also highlighted the limitations of community-based WES studies compared with high myopia case-control WES studies.
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Wen Y, Dai B, Zhang X, Zhu H, Xie C, Xia J, Sun Y, Zhu M, Tong J, Shen Y. Retinal Transcriptomics Analysis Reveals the Underlying Mechanism of Disturbed Emmetropization Induced by Wavelength Defocus. Curr Eye Res 2022; 47:908-917. [PMID: 35225751 DOI: 10.1080/02713683.2022.2048395] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 02/24/2022] [Indexed: 12/28/2022]
Abstract
PURPOSE Wavelength signals play a vital role in refractive development. This study aimed to explore the retinal transcriptome signature in these processes. METHODS Guinea pigs were randomly divided into three groups exposed to white, blue, or green environmental light for eight weeks. Refraction and axial length were evaluated every 4 weeks, and the retinal transcriptome was profiled at 8 weeks. RESULTS Compared with the white group, ocular refraction significantly decreased and ocular axial length significantly extended in the green group whereas these parameters showed opposite trends in the blue group. RNA-sequencing showed that, compared with the white group, 184 and 171 differentially expressed genes (DEGs) were found in the blue and green groups, respectively. Among these DEGs, only 31 overlapped. These two sets of DEGs were enriched in distinct biological processes and pathways. There were 268 DEGs between the blue and green groups, which were primarily enriched in the extracellular matrix, and metabolism, receptor activity, and ion binding processes. In addition, nine human genes, including ECEL1, CHRND, SHBG, PRSS56, OVOL1, RDH5, WNT7B, PEBP4, CA12, were identified to be related to myopia development and wavelength response, indicating the potential role of these genes in human wavelength-induced myopia. CONCLUSIONS In this study, we identified retinal targets and pathways involved in the response to wavelength signals in emmetropization.
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Simcoe MJ, Shah A, Fan B, Choquet H, Weisschuh N, Waseem NH, Jiang C, Melles RB, Ritch R, Mahroo OA, Wissinger B, Jorgenson E, Wiggs JL, Garway-Heath DF, Hysi PG, Hammond CJ. Genome-Wide Association Study Identifies Two Common Loci Associated with Pigment Dispersion Syndrome/Pigmentary Glaucoma and Implicates Myopia in its Development. Ophthalmology 2022; 129:626-636. [PMID: 35031440 DOI: 10.1016/j.ophtha.2022.01.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 01/03/2022] [Accepted: 01/05/2022] [Indexed: 11/27/2022] Open
Abstract
PURPOSE To identify genetic variants associated with pigment dispersion syndrome (PDS) and pigmentary glaucoma (PG) in unrelated patients and to further understand the genetic and potentially causal relationships between PDS and associated risk factors. DESIGN A 2-stage genome-wide association meta-analysis with replication and subsequent in silico analyses including Mendelian randomization. PARTICIPANTS A total of 574 cases with PG or PDS and 52 627 controls of European descent. METHODS Genome-wide association analyses were performed in 4 cohorts and meta-analyzed in 3 stages: (1) a discovery meta-analysis was performed in 3 cohorts, (2) replication was performed in the fourth cohort, and (3) all 4 cohorts were meta-analyzed to increase statistical power. Two-sample Mendelian randomization was used to determine whether refractive error and intraocular pressure exert causal effects over PDS. MAIN OUTCOME MEASURES The association of genetic variants with PDS and whether myopia exerts causal effects over PDS. RESULTS Significant association was present at 2 novel loci for PDS/PG. These loci and follow-up analyses implicate the genes gamma secretase activator protein (GSAP) (lead single nucleotide polymorphism [SNP]: rs9641220, P = 6.0×10-10) and glutamate metabotropic receptor 5 (GRM5)/TYR (lead SNP: rs661177, P = 3.9×10-9) as important factors in disease risk. Mendelian randomization showed significant evidence that negative refractive error (myopia) exerts a direct causal effect over PDS (P = 8.86×10-7). CONCLUSIONS Common SNPs relating to the GSAP and GRM5/TYR genes are associated risk factors for the development of PDS and PG. Although myopia is a known risk factor, this study uses genetic data to demonstrate that myopia is, in part, a cause of PDS and PG.
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Neitz M, Wagner-Schuman M, Rowlan JS, Kuchenbecker JA, Neitz J. Insight from OPN1LW Gene Haplotypes into the Cause and Prevention of Myopia. Genes (Basel) 2022; 13:genes13060942. [PMID: 35741704 PMCID: PMC9222437 DOI: 10.3390/genes13060942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 05/18/2022] [Accepted: 05/24/2022] [Indexed: 02/01/2023] Open
Abstract
Nearsightedness (myopia) is a global health problem of staggering proportions that has driven the hunt for environmental and genetic risk factors in hopes of gaining insight into the underlying mechanism and providing new avenues of intervention. Myopia is the dominant risk factor for leading causes of blindness, including myopic maculopathy and retinal detachment. The fundamental defect in myopia—an excessively elongated eyeball—causes blurry distance vision that is correctable with lenses or surgery, but the risk of blindness remains. Haplotypes of the long-wavelength and middle-wavelength cone opsin genes (OPN1LW and OPN1MW, respectively) that exhibit profound exon-3 skipping during pre-messenger RNA splicing are associated with high myopia. Cone photoreceptors expressing these haplotypes are nearly devoid of photopigment. Conversely, cones in the same retina that express non-skipping haplotypes are relatively full of photopigment. We hypothesized that abnormal contrast signals arising from adjacent cones differing in photopigment content stimulate axial elongation, and spectacles that reduce contrast may significantly slow myopia progression. We tested for an association between spherical equivalent refraction and OPN1LW haplotype in males of European ancestry as determined by long-distance PCR and Sanger sequencing and identified OPN1LW exon 3 haplotypes that increase the risk of common myopia. We also evaluated the effects of contrast-reducing spectacles lenses on myopia progression in children. The work presented here provides new insight into the cause and prevention of myopia progression.
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Jiang X, Xu Z, Soorma T, Tariq A, Bhatti T, Baneke AJ, Pontikos N, Leo SM, Webster AR, Williams KM, Hammond CJ, Hysi PG, Mahroo OA. Electrical responses from human retinal cone pathways associate with a common genetic polymorphism implicated in myopia. Proc Natl Acad Sci U S A 2022; 119:e2119675119. [PMID: 35594404 PMCID: PMC9173800 DOI: 10.1073/pnas.2119675119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 04/08/2022] [Indexed: 11/25/2022] Open
Abstract
Myopia is the commonest visual impairment. Several genetic loci confer risk, but mechanisms by which they do this are unknown. Retinal signals drive eye growth, and myopia usually results from an excessively long eye. The common variant most strongly associated with myopia is near the GJD2 gene, encoding connexin-36, which forms retinal gap junctions. Light-evoked responses of retinal neurons can be recorded noninvasively as the electroretinogram (ERG). We analyzed these responses from 186 adult twin volunteers who had been genotyped at this locus. Participants underwent detailed ERG recordings incorporating international standard stimuli as well as experimental protocols aiming to separate dark-adapted rod- and cone-driven responses. A mixed linear model was used to explore association between allelic dosage at the locus and international standard ERG parameters after adjustment for age, sex, and family structure. Significant associations were found for parameters of light-adapted, but not dark-adapted, responses. Further investigation of isolated rod- and cone-driven ERGs confirmed associations with cone-driven, but not rod-driven, a-wave amplitudes. Comparison with responses to similar experimental stimuli from a patient with a prior central retinal artery occlusion, and from two patients with selective loss of ON-bipolar cell signals, was consistent with the associated parameters being derived from signals from cone-driven OFF-bipolar cells. Analysis of single-cell transcriptome data revealed strongest GJD2 expression in cone photoreceptors; bipolar cell expression appeared strongest in OFF-bipolar cells and weakest in rod-driven ON-bipolar cells. Our findings support a potential role for altered signaling in cone-driven OFF pathways in myopia development.
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González-Iglesias E, López-Vázquez A, Noval S, Nieves-Moreno M, Granados-Fernández M, Arruti N, Rosa-Pérez I, Pacio-Míguez M, Montaño VEF, Rodríguez-Solana P, del Pozo A, Santos-Simarro F, Vallespín E. Next-Generation Sequencing Screening of 43 Families with Non-Syndromic Early-Onset High Myopia: A Clinical and Genetic Study. Int J Mol Sci 2022; 23:ijms23084233. [PMID: 35457050 PMCID: PMC9031962 DOI: 10.3390/ijms23084233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 04/04/2022] [Indexed: 02/01/2023] Open
Abstract
Early-onset high myopia (EoHM) is a disease that causes a spherical refraction error of ≥-6 diopters before 10 years of age, with potential multiple ocular complications. In this article, we report a clinical and genetic study of 43 families with EoHM recruited in our center. A complete ophthalmological evaluation was performed, and a sample of peripheral blood was obtained from proband and family members. DNA was analyzed using a customized next-generation sequencing panel that included 419 genes related to ophthalmological disorders with a suspected genetic cause, and genes related to EoHM pathogenesis. We detected pathogenic and likely pathogenic variants in 23.9% of the families and detected variants of unknown significance in 76.1%. Of these, 5.7% were found in genes related to non-syndromic EoHM, 48.6% in genes associated with inherited retinal dystrophies that can include a syndromic phenotype, and 45.7% in genes that are not directly related to EoHM or retinal dystrophy. We found no candidate genes in 23% of the patients, which suggests that further studies are needed. We propose a systematic genetic analysis for patients with EoHM because it helps with follow-up, prognosis and genetic counseling.
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Ando Y, Keino H, Inoue M, Hirota K, Takahashi H, Sano K, Koto T, Sato T, Takeuchi M, Hirakata A. Circulating Vitreous microRNA as Possible Biomarker in High Myopic Eyes with Macular Hole. Int J Mol Sci 2022; 23:ijms23073647. [PMID: 35409006 PMCID: PMC8998168 DOI: 10.3390/ijms23073647] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 01/27/2023] Open
Abstract
High myopia is a major cause of irreversible visual impairment globally. In the present study, we investigated the microRNA (miRNA) profile in the vitreous of macular hole (MH) and high myopic MH. We performed miRNA analysis using TaqMan® Low Density Arrays (Thermo Fisher Scientific, Waltham, MA, USA) to investigate the circulating vitreous miRNA profile from patients with MH (axial length < 26.5 mm, n = 11) and high myopic MH (axial length ≥ 26.5 mm, n = 11) who underwent pars plana vitrectomy. The vitreous inflammatory cytokine signature was examined in high myopic MH eyes using a multiplex assay. A miRNA-Array analysis revealed that let-7c was significantly up-regulated and miR-200a was significantly down-regulated in high myopic MH eyes compared to those in MH eyes. The bioinformatics analysis for up-regulated miRNA targeted gene identified 23 pathways including mitogen-activated protein kinase (MAPK) and several inflammatory signaling pathways, whereas the bioinformatics analysis for down-regulated miRNA targeted genes showed 32 enriched pathways including phosphoinositide 3-kinase/protein kinase B (PI3K/AKT). The levels of inflammatory cytokines including IP-10, IFN-γ, and MCP-1 were significantly higher in the vitreous of high myopic MH eyes. These results suggest that specific miRNAs expressed in the vitreous may be associated with the pathological condition of high myopic MH and the above mentioned miRNAs may contribute to the development of inflammatory status in the vitreous of high myopic eyes.
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Li Q, Zheng Q, He J, Li L, Xie X, Liang H. Hsa-miR-142-3p reduces collagen I in human scleral fibroblasts by targeting TGF-β1 in high myopia. Exp Eye Res 2022; 219:109023. [PMID: 35276183 DOI: 10.1016/j.exer.2022.109023] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 03/01/2022] [Accepted: 03/04/2022] [Indexed: 11/18/2022]
Abstract
High myopia has been continually increasing globally until now and often results in visual impairment. Scleral extracellular matrix (ECM) remodeling is considered a common factor contributing to progression of myopia. However, the role of microRNAs (miRNAs) in regulating scleral ECM organization is not well understood. We aimed to explore the effect and regulatory mechanism of hsa-miR-142-3p on collagen I in human scleral fibroblasts in high myopia. First, next-generation sequencing was conducted to identify 37 miRNAs differentially expressed in the aqueous humor of high myopia samples and control samples. Furthermore, hsa-miR-142-3p in the aqueous humor was found to positively relate to the ocular axial length. Besides, the results of immunofluorescence and Western blot assay indicated that hsa-miR-142-3p overexpression decreased collagen I expression in the human fetal scleral fibroblasts (HFSFs); while hsa-miR-142-3p downregulation increased collagen I. Moreover, hsa-miR-142-3p targets TGFβ-1 gene expression. Quantitative polymerase chain reaction (qPCR) and Western blot analysis showed that miRNA 142-3p reduced TGFβ-1 expression while an inhibitor had an opposite effect. Therefore, there is an inverse relationship between changes in miR-142-3p expression levels and those of collagen1a1 in human scleral fibroblasts. Such a dependence suggests that miR-142-3p may be a target to improve therapeutic management of this condition.
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van der Sande E, Haarman AEG, Quint WH, Tadema KCD, Meester-Smoor MA, Kamermans M, De Zeeuw CI, Klaver CCW, Winkelman BHJ, Iglesias AI. The Role of GJD2(Cx36) in Refractive Error Development. Invest Ophthalmol Vis Sci 2022; 63:5. [PMID: 35262731 PMCID: PMC8934558 DOI: 10.1167/iovs.63.3.5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 02/16/2022] [Indexed: 02/06/2023] Open
Abstract
Refractive errors are common eye disorders characterized by a mismatch between the focal power of the eye and its axial length. An increased axial length is a common cause of the refractive error myopia (nearsightedness). The substantial increase in myopia prevalence over the last decades has raised public health concerns because myopia can lead to severe ocular complications later in life. Genomewide association studies (GWAS) have made considerable contributions to the understanding of the genetic architecture of refractive errors. Among the hundreds of genetic variants identified, common variants near the gap junction delta-2 (GJD2) gene have consistently been reported as one of the top hits. GJD2 encodes the connexin 36 (Cx36) protein, which forms gap junction channels and is highly expressed in the neural retina. In this review, we provide current evidence that links GJD2(Cx36) to the development of myopia. We summarize the gap junctional communication in the eye and the specific role of GJD2(Cx36) in retinal processing of visual signals. Finally, we discuss the pathways involving dopamine and gap junction phosphorylation and coupling as potential mechanisms that may explain the role of GJD2(Cx36) in refractive error development.
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Liu L, Zhu D, Ding W, Zhang T, Ma X, Zou J. MiRNA-21- HIF-1α-VEGF Axis is Associated with Myopic Choroidal Neovascularization in Guinea Pigs. Ophthalmic Res 2022; 65:493-505. [PMID: 35158368 DOI: 10.1159/000522511] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 02/05/2022] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Myopic choroidal neovascularization (mCNV) often causes serious damage to central vision. The mechanisms behind it remain unclear. METHOD In this study, monocular form deprivation was applied to induce high myopia and 532 nm laser was employed to induce CNV in guinea pig. The development of neovascularization was measured comprehensively by fundus fluorescein angiography, Optical coherence tomography and HE-staining. Gene expression was detected by real-time polymerase chain reaction and Immunohistochemistry. RESULTS The proliferation of new blood vessels increased with time and peaked at 21 d. At each time point after laser photocoagulation, the incidence of CNV was higher in form-deprived myopia (FDM) group than in control group. Myopic CNV started earlier and decreased more slowly. The obvious continuous fluorescein leakage could last as long as one month. The expressions of hypoxia-inducible factor (HIF)-1α and vascular endothelial growth factor (VEGF) increased and peaked at 14 d in both groups after laser photocoagulation. Moreover, after laser photocoagulation, miR-21 expression was upregulated in both groups, reached a peak at 7 d, with a level much higher in FDM group. In addition, miR-21 expression was positively correlated with VEGF and HIF-1α expression in both groups. CONCLUSION miR-21 correlated with HIF-1α-VEGF signaling pathway may promote CNV formation in high-myopia guinea.
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[Chinese expert consensus on the reference interval of ocular hyperopia reserve, axial length, corneal curvature and genetic factors in school-age children (2022)]. [ZHONGHUA YAN KE ZA ZHI] CHINESE JOURNAL OF OPHTHALMOLOGY 2022; 58:96-102. [PMID: 35144349 DOI: 10.3760/cma.j.cn112142-20210603-00267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Myopia is a focal issue affecting the eye health of children and adolescents in China. Hyperopia reserve is the refractive state before the occurrence of myopia. As the result of dynamic matching between the axial length, cornea and lens, it is of great significance to the prevention and control of myopia. There has been a lack of the reference basis for children's eyeball development parameters and the influence of genetic factors, especially the changing law of the above-mentioned parameters in the process of children's "emmetropization". To promote the prevention and control of myopia in children and adolescents and to standardize population screening and clinical treatment, based on the survey data of refractive errors in children and adolescents from different regions, a consensus has been reached on the reference interval of hyperopia reserve, axial length and corneal curvature and related genetic factors of emmetropia at different ages among school-age children by the Public Health Ophthalmology Branch of the Chinese Preventive Medicine Association.
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Long KR, Rbaibi Y, Bondi CD, Ford BR, Poholek AC, Boyd-Shiwarski CR, Tan RJ, Locker JD, Weisz OA. Cubilin-, megalin-, and Dab2-dependent transcription revealed by CRISPR/Cas9 knockout in kidney proximal tubule cells. Am J Physiol Renal Physiol 2022; 322:F14-F26. [PMID: 34747197 PMCID: PMC8698540 DOI: 10.1152/ajprenal.00259.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 11/01/2021] [Accepted: 11/01/2021] [Indexed: 01/03/2023] Open
Abstract
The multiligand receptors megalin (Lrp2) and cubilin (Cubn) and their endocytic adaptor protein Dab2 (Dab2) play essential roles in maintaining the integrity of the apical endocytic pathway of proximal tubule (PT) cells and have complex and poorly understood roles in the development of chronic kidney disease. Here, we used RNA-sequencing and CRISPR/Cas9 knockout (KO) technology in a well-differentiated cell culture model to identify PT-specific transcriptional changes that are directly consequent to the loss of megalin, cubilin, or Dab2 expression. KO of Lrp2 had the greatest transcriptional effect, and nearly all genes whose expression was affected in Cubn KO and Dab2 KO cells were also changed in Lrp2 KO cells. Pathway analysis and more granular inspection of the altered gene profiles suggested changes in pathways with immunomodulatory functions that might trigger the pathological changes observed in KO mice and patients with Donnai-Barrow syndrome. In addition, differences in transcription patterns between Lrp2 and Dab2 KO cells suggested the possibility that altered spatial signaling by aberrantly localized receptors contributes to transcriptional changes upon the disruption of PT endocytic function. A reduction in transcripts encoding sodium-glucose cotransporter isoform 2 was confirmed in Lrp2 KO mouse kidney lysates by quantitative PCR analysis. Our results highlight the role of megalin as a master regulator and coordinator of ion transport, metabolism, and endocytosis in the PT. Compared with the studies in animal models, this approach provides a means to identify PT-specific transcriptional changes that are directly consequent to the loss of these target genes.NEW & NOTEWORTHY Megalin and cubilin receptors together with their adaptor protein Dab2 represent major components of the endocytic machinery responsible for efficient uptake of filtered proteins by the proximal tubule (PT). Dab2 and megalin expression have been implicated as both positive and negative modulators of kidney disease. We used RNA sequencing to knock out CRISPR/Cas9 cubilin, megalin, and Dab2 in highly differentiated PT cells to identify PT-specific changes that are directly consequent to knockout of each component.
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MESH Headings
- Adaptor Proteins, Signal Transducing/genetics
- Adaptor Proteins, Signal Transducing/metabolism
- Agenesis of Corpus Callosum/genetics
- Agenesis of Corpus Callosum/metabolism
- Agenesis of Corpus Callosum/pathology
- Animals
- Apoptosis Regulatory Proteins/genetics
- Apoptosis Regulatory Proteins/metabolism
- CRISPR-Associated Protein 9/genetics
- CRISPR-Cas Systems
- Cells, Cultured
- Databases, Genetic
- Gene Knockout Techniques
- Gene Regulatory Networks
- Hearing Loss, Sensorineural/genetics
- Hearing Loss, Sensorineural/metabolism
- Hearing Loss, Sensorineural/pathology
- Hernias, Diaphragmatic, Congenital/genetics
- Hernias, Diaphragmatic, Congenital/metabolism
- Hernias, Diaphragmatic, Congenital/pathology
- Humans
- Kidney Tubules, Proximal/metabolism
- Kidney Tubules, Proximal/pathology
- Low Density Lipoprotein Receptor-Related Protein-2/genetics
- Low Density Lipoprotein Receptor-Related Protein-2/metabolism
- Male
- Mice, Knockout
- Monodelphis
- Myopia/genetics
- Myopia/metabolism
- Myopia/pathology
- Proteinuria/genetics
- Proteinuria/metabolism
- Proteinuria/pathology
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/metabolism
- Renal Tubular Transport, Inborn Errors/genetics
- Renal Tubular Transport, Inborn Errors/metabolism
- Renal Tubular Transport, Inborn Errors/pathology
- Transcription, Genetic
- Mice
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Hong N, Jiang B, Gu L, Chen SY, Tong JP. MicroRNA expression profiling in myopia: a meta-analysis and systematic review. Ophthalmic Res 2021; 65:254-263. [PMID: 34959240 DOI: 10.1159/000521300] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 11/21/2021] [Indexed: 11/19/2022]
Abstract
BACKGROUND Myopia (nearsightedness) is currently the most common human eye disorder worldwide. In the recent years, several studies have addressed the role of microRNAs (miRNAs) in the pathogenesis of myopia. OBJECTIVES The aim of this study was to perform a meta-analysis on the miRNA expression profiling studies in myopia to identify commonly dysregulated miRNAs in myopic tissues. METHOD Seven independent studies were included in the meta-analysis. A vote-counting strategy were employed as the meta-analysis method. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis and Gene Ontology (GO) functional enrichment analysis were performed to identify the pathways most strongly affected by the dysregulated mouse miRNAs. RESULTS According to the vote-counting method, eighteen miRNAs were reported in at least two studies with the consistent direction, of which 13 miRNAs were commonly up-regulated in myopic samples compared with control samples and five miRNAs were commonly down-regulated. Subgroup analyses divided and compared the differentially expressed miRNAs according to species (human and animal) and ocular tissue types. The KEGG analysis showed that the dysregulated mouse miRNAs were most enriched in extracellular matrix (ECM)-receptor interaction signal pathway. The most enriched GO processes regulated by the dysregulated mouse miRNAs was cellular protein modification process. CONCLUSIONS Our meta-analysis recommends several miRNAs may provide some clues of the potential biomarkers in myopia. Further mechanistic studies are warranted to elucidate the biological role of the dysregulated miRNAs in the development of myopia.
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Yang J, Ouyang X, Fu H, Hou X, Liu Y, Xie Y, Yu H, Wang G. Advances in biomedical study of the myopia-related signaling pathways and mechanisms. Biomed Pharmacother 2021; 145:112472. [PMID: 34861634 DOI: 10.1016/j.biopha.2021.112472] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 11/18/2021] [Accepted: 11/23/2021] [Indexed: 11/18/2022] Open
Abstract
Myopia has become one of the most critical health problems in the world with the increasing time spent indoors and increasing close work. Pathological myopia may have multiple complications, such as myopic macular degeneration, retinal detachment, cataracts, open-angle glaucoma, and severe cases that can cause blindness. Mounting evidence suggests that the cause of myopia can be attributed to the complex interaction of environmental exposure and genetic susceptibility. An increasing number of researchers have focused on the genetic pathogenesis of myopia in recent years. Scleral remodeling and excessive axial elongating induced retina thinning and even retinal detachment are myopia's most important pathological manifestations. The related signaling pathways are indispensable in myopia occurrence and development, such as dopamine, nitric oxide, TGF-β, HIF-1α, etc. We review the current major and recent progress of biomedicine on myopia-related signaling pathways and mechanisms.
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118
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Zeng L, Li X, Liu J, Liu H, Xu H, Yang Z. RNA-Seq Analysis Reveals an Essential Role of the Tyrosine Metabolic Pathway and Inflammation in Myopia-Induced Retinal Degeneration in Guinea Pigs. Int J Mol Sci 2021; 22:ijms222212598. [PMID: 34830490 PMCID: PMC8618104 DOI: 10.3390/ijms222212598] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 11/15/2021] [Accepted: 11/17/2021] [Indexed: 12/26/2022] Open
Abstract
Myopia is the second leading cause of visual impairment globally. Myopia can induce sight-threatening retinal degeneration and the underlying mechanism remains poorly defined. We generated a model of myopia-induced early-stage retinal degeneration in guinea pigs and investigated the mechanism of action. Methods: The form-deprivation-induced myopia (FDM) was induced in the right eyes of 2~3-week-old guinea pigs using a translucent balloon for 15 weeks. The left eye remained untreated and served as a self-control. Another group of untreated age-matched animals was used as naïve controls. The refractive error and ocular biometrics were measured at 3, 7, 9, 12 and 15 weeks post-FDM induction. Visual function was evaluated by electroretinography. Retinal neurons and synaptic structures were examined by confocal microscopy of immunolabelled retinal sections. The total RNAs were extracted from the retinas and processed for RNA sequencing analysis. Results: The FDM eyes presented a progressive axial length elongation and refractive error development. After 15 weeks of intervention, the average refractive power was -3.40 ± 1.85 D in the FDM eyes, +2.94 ± 0.59 D and +2.69 ± 0.56 D in the self-control and naïve control eyes, respectively. The a-wave amplitude was significantly lower in FDM eyes and these eyes had a significantly lower number of rods, secretagogin+ bipolar cells, and GABAergic amacrine cells in selected retinal areas. RNA-seq analysis showed that 288 genes were upregulated and 119 genes were downregulated in FDM retinas compared to naïve control retinas. In addition, 152 genes were upregulated and 12 were downregulated in FDM retinas compared to self-control retinas. The KEGG enrichment analysis showed that tyrosine metabolism, ABC transporters and inflammatory pathways were upregulated, whereas tight junction, lipid and glycosaminoglycan biosynthesis were downregulated in FDM eyes. Conclusions: The long-term (15-week) FDM in the guinea pig models induced an early-stage retinal degeneration. The dysregulation of the tyrosine metabolism and inflammatory pathways may contribute to the pathogenesis of myopia-induced retinal degeneration.
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Foo LL, Ng WY, Lim GYS, Tan TE, Ang M, Ting DSW. Artificial intelligence in myopia: current and future trends. Curr Opin Ophthalmol 2021; 32:413-424. [PMID: 34310401 DOI: 10.1097/icu.0000000000000791] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
PURPOSE OF REVIEW Myopia is one of the leading causes of visual impairment, with a projected increase in prevalence globally. One potential approach to address myopia and its complications is early detection and treatment. However, current healthcare systems may not be able to cope with the growing burden. Digital technological solutions such as artificial intelligence (AI) have emerged as a potential adjunct for myopia management. RECENT FINDINGS There are currently four significant domains of AI in myopia, including machine learning (ML), deep learning (DL), genetics and natural language processing (NLP). ML has been demonstrated to be a useful adjunctive for myopia prediction and biometry for cataract surgery in highly myopic individuals. DL techniques, particularly convoluted neural networks, have been applied to various image-related diagnostic and predictive solutions. Applications of AI in genomics and NLP appear to be at a nascent stage. SUMMARY Current AI research is mainly focused on disease classification and prediction in myopia. Through greater collaborative research, we envision AI will play an increasingly critical role in big data analysis by aggregating a greater variety of parameters including genomics and environmental factors. This may enable the development of generalizable adjunctive DL systems that could help realize predictive and individualized precision medicine for myopic patients.
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Koschak A, Fernandez-Quintero ML, Heigl T, Ruzza M, Seitter H, Zanetti L. Cav1.4 dysfunction and congenital stationary night blindness type 2. Pflugers Arch 2021; 473:1437-1454. [PMID: 34212239 PMCID: PMC8370969 DOI: 10.1007/s00424-021-02570-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 04/14/2021] [Accepted: 04/18/2021] [Indexed: 12/04/2022]
Abstract
Cav1.4 L-type Ca2+ channels are predominantly expressed in retinal neurons, particularly at the photoreceptor terminals where they mediate sustained Ca2+ entry needed for continuous neurotransmitter release at their ribbon synapses. Cav1.4 channel gating properties are controlled by accessory subunits, associated regulatory proteins, and also alternative splicing. In humans, mutations in the CACNA1F gene encoding for Cav1.4 channels are associated with X-linked retinal disorders such as congenital stationary night blindness type 2. Mutations in the Cav1.4 protein result in a spectrum of altered functional channel activity. Several mouse models broadened our understanding of the role of Cav1.4 channels not only as Ca2+ source at retinal synapses but also as synaptic organizers. In this review, we highlight different structural and functional phenotypes of Cav1.4 mutations that might also occur in patients with congenital stationary night blindness type 2. A further important yet mostly neglected aspect that we discuss is the influence of alternative splicing on channel dysfunction. We conclude that currently available functional phenotyping strategies should be refined and summarize potential specific therapeutic options for patients carrying Cav1.4 mutations. Importantly, the development of new therapeutic approaches will permit a deeper understanding of not only the disease pathophysiology but also the physiological function of Cav1.4 channels in the retina.
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MESH Headings
- 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester/pharmacology
- Animals
- Calcium Channel Agonists/pharmacology
- Calcium Channels, L-Type/genetics
- Calcium Channels, L-Type/metabolism
- Eye Diseases, Hereditary/genetics
- Eye Diseases, Hereditary/metabolism
- Genetic Diseases, X-Linked/genetics
- Genetic Diseases, X-Linked/metabolism
- Humans
- Mutation/physiology
- Myopia/genetics
- Myopia/metabolism
- Night Blindness/genetics
- Night Blindness/metabolism
- Retina/drug effects
- Retina/metabolism
- Synapses/drug effects
- Synapses/genetics
- Synapses/metabolism
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121
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Haarman AEG, Enthoven CA, Tedja MS, Polling JR, Tideman JWL, Keunen JEE, Boon CJF, Felix JF, Raat H, Geerards AJM, Luyten GPM, van Rijn GA, Verhoeven VJM, Klaver CCW. Phenotypic Consequences of the GJD2 Risk Genotype in Myopia Development. Invest Ophthalmol Vis Sci 2021; 62:16. [PMID: 34406332 PMCID: PMC8375003 DOI: 10.1167/iovs.62.10.16] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 01/26/2021] [Indexed: 12/12/2022] Open
Abstract
Purpose To study the relatively high effect of the refractive error gene GJD2 in human myopia, and to assess its relationship with refractive error, ocular biometry and lifestyle in various age groups. Methods The population-based Rotterdam Study (RS), high myopia case-control study MYopia STudy, and the birth-cohort study Generation R were included in this study. Spherical equivalent (SER), axial length (AL), axial length/corneal radius (AL/CR), vitreous depth (VD), and anterior chamber depth (ACD) were measured using standard ophthalmologic procedures. Biometric measurements were compared between GJD2 (rs524952) genotype groups; education and environmental risk score (ERS) were calculated to estimate gene-environment interaction effects, using the Synergy index (SI). Results RS adults carrying two risk alleles had a lower SER and longer AL, ACD and VD (AA versus TT, 0.23D vs. 0.70D; 23.79 mm vs. 23.52 mm; 2.72 mm vs. 2.65 mm; 16.12 mm vs. 15.87 mm; all P < 0.001). Children carrying two risk alleles had larger AL/CR at ages 6 and 9 years (2.88 vs. 2.87 and 3.00 vs. 2.96; all P < 0.001). Education and ERS both negatively influenced myopia and the biometric outcomes, but gene-environment interactions did not reach statistical significance (SI 1.25 [95% confidence interval {CI}, 0.85-1.85] and 1.17 [95% CI, 0.55-2.50] in adults and children). Conclusions The elongation of the eye caused by the GJD2 risk genotype follows a dose-response pattern already visible at the age of 6 years. These early effects are an example of how a common myopia gene may drive myopia.
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Burgess FR, Carroll N, Young SL, Schmoll C, Lampe AK, Chan J. A short-sighted approach to high myopia-not just an eye problem. J AAPOS 2021; 25:247-248. [PMID: 34166818 DOI: 10.1016/j.jaapos.2021.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 03/16/2021] [Accepted: 03/26/2021] [Indexed: 11/17/2022]
Abstract
We present the first case of rapid onset high myopia in early childhood as the presenting feature of Loeys-Dietz syndrome. The patient progressed from a normal degree of hyperopia (+2 diopter sphere [DS]) at 18 months of age to high myopia (-10 DS) 9 months later. Subsequent genetic testing revealed both her brothers and her father to carry the same TGFB3 pathogenic variant. This case aims to highlight the importance of considering systemic conditions in children with high myopia.
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123
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Yuan XL, Zhang R, Zheng Y, Sun L, Wang G, Chen S, Xu Y, Chen SL, Qiu K, Ng TK. Corneal curvature-associated MTOR variant differentiates mild myopia from high myopia in Han Chinese population. Ophthalmic Genet 2021; 42:446-457. [PMID: 33979260 DOI: 10.1080/13816810.2021.1923035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 02/27/2021] [Accepted: 04/18/2021] [Indexed: 02/05/2023]
Abstract
BACKGROUND Myopia is the most prevalent ocular disorder in the world, and corneal parameters have been regarded as key ocular biometric parameters determining the refractive status. Here, we aimed to determine the association of genome-wide association study-identified corneal curvature (CC)-related gene variants with different severity of myopia and ocular biometric parameters in Chinese population. METHODS Total 2,101 unrelated Han Chinese subjects were recruited, including 1,649 myopia and 452 control subjects. Five previously reported CC-associated gene variants (PDGFRA, MTOR, WNT7B, CMPK1 and RBP3) were genotyped by TaqMan assay, and their association with different myopia severity and ocular biometric parameters were evaluated. RESULTS Joint additive effect analysis showed that MTOR rs74225573 paired with PDGFRA rs2114039 (P = .009, odds ratio (OR) = 4.91) or CMPK1 rs17103186 (P = .002, OR = 13.03) were significantly associated with higher risk in mild myopia. Critically, mild myopia subjects had significantly higher frequency in MTOR rs74225573 C allele than high myopia subjects (P = .003), especially in male subjects (P = .001, OR = 0.49). High myopia subjects carrying MTOR rs74225573 C allele have significant flatter CC (P = .035) and longer corneal radius (P = .044) than those carrying TT genotype. CONCLUSION This study revealed that male high myopia subjects are more prone to carry CC-related MTOR rs74225573 T allele, whereas mild myopia subjects are prone to carry the C allele. MTOR rs7422573 variant could be a genetic marker to differentiate mild from high myopia in risk assessment. ABBREVIATIONS ACD: anterior chamber depth; AL: axial length; AL/CR: axial length/corneal radius ratio; ANOVA: analysis of variance; CC: corneal curvature; CCT: central corneal thickness; C.I.: confidence interval; CMPK1: cytidine/uridine monophosphate kinase 1; CR: corneal radius; D: diopter; GWAS: genome-wide association studies; HWE: Hardy-Weinberg equilibrium; LT: lens thickness; MIPEP: mitochondrial intermediate peptidase; MTOR: mechanistic target of rapamycin kinase; OR: odds ratio; PDGFRA: platelet-derived growth factor receptor-α; RBP3: retinol-binding protein 3; SD: standard deviation; SE: spherical equivalence; SNTB1: syntrophin beta 1; VCD: vitreous chamber depth; VIPR2: vasoactive intestinal peptide receptor 2; WNT7B: wingless/integrated family member 7B.
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Al Sayed ZR, Canac R, Cimarosti B, Bonnard C, Gourraud JB, Hamamy H, Kayserili H, Girardeau A, Jouni M, Jacob N, Gaignerie A, Chariau C, David L, Forest V, Marionneau C, Charpentier F, Loussouarn G, Lamirault G, Reversade B, Zibara K, Lemarchand P, Gaborit N. Human model of IRX5 mutations reveals key role for this transcription factor in ventricular conduction. Cardiovasc Res 2021; 117:2092-2107. [PMID: 32898233 DOI: 10.1093/cvr/cvaa259] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 01/15/2020] [Accepted: 08/28/2020] [Indexed: 01/02/2023] Open
Abstract
AIMS Several inherited arrhythmic diseases have been linked to single gene mutations in cardiac ion channels and interacting proteins. However, the mechanisms underlying most arrhythmias, are thought to involve altered regulation of the expression of multiple effectors. In this study, we aimed to examine the role of a transcription factor (TF) belonging to the Iroquois homeobox family, IRX5, in cardiac electrical function. METHODS AND RESULTS Using human cardiac tissues, transcriptomic correlative analyses between IRX5 and genes involved in cardiac electrical activity showed that in human ventricular compartment, IRX5 expression strongly correlated to the expression of major actors of cardiac conduction, including the sodium channel, Nav1.5, and Connexin 40 (Cx40). We then generated human-induced pluripotent stem cells (hiPSCs) derived from two Hamamy syndrome-affected patients carrying distinct homozygous loss-of-function mutations in IRX5 gene. Cardiomyocytes derived from these hiPSCs showed impaired cardiac gene expression programme, including misregulation in the control of Nav1.5 and Cx40 expression. In accordance with the prolonged QRS interval observed in Hamamy syndrome patients, a slower ventricular action potential depolarization due to sodium current reduction was observed on electrophysiological analyses performed on patient-derived cardiomyocytes, confirming the functional role of IRX5 in electrical conduction. Finally, a cardiac TF complex was newly identified, composed by IRX5 and GATA4, in which IRX5 potentiated GATA4-induction of SCN5A expression. CONCLUSION Altogether, this work unveils a key role for IRX5 in the regulation of human ventricular depolarization and cardiac electrical conduction, providing therefore new insights into our understanding of cardiac diseases.
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Rashwan R, Hunt DM, Carvalho LS. The role of voltage-gated ion channels in visual function and disease in mammalian photoreceptors. Pflugers Arch 2021; 473:1455-1468. [PMID: 34255151 DOI: 10.1007/s00424-021-02595-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 05/31/2021] [Accepted: 06/10/2021] [Indexed: 12/26/2022]
Abstract
Light activation of the classical light-sensing retinal neurons, the photoreceptors, results in a graded change in membrane potential that ultimately leads to a reduction in neurotransmitter release to the post-synaptic retinal neurons. Photoreceptors show striking powers of adaptation, and for visual processing to function optimally, they must adjust their gain to remain responsive to different levels of ambient light intensity. The presence of a tightly controlled balance of inward and outward currents modulated by several different types of ion channels is what gives photoreceptors their remarkably dynamic operating range. Part of the resetting and modulation of this operating range is controlled by potassium and calcium voltage-gated channels, which are involved in setting the dark resting potential and synapse signal processing, respectively. Their essential contribution to visual processing is further confirmed in patients suffering from cone dystrophy with supernormal rod response (CDSRR) and congenital stationary night blindness type 2 (CSNB2), both conditions that lead to irreversible vision loss. This review will discuss these two types of voltage-gated ion channels present in photoreceptors, focussing on their structure and physiology, and their role in visual processing. It will also discuss the use and benefits of knockout mouse models to further study the function of these channels and what routes to potential treatments could be applied for CDSRR and CSNB2.
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