Tkatchenko, A. V., Tkatchenko, T. V., Guggenheim, J. A., Verhoeven, V. J. M., Hysi, P. G., Wojciechowski, R., Singh, P. K., Kumar, A., Thinakaran, G., Williams, C. (2015). APLP2 Regulates Refractive Error and Myopia Development in Mice and Humans. PLoS Genetics, 11(8), [e1005432]. https://doi.org/10.1371/journal.pgen.1005432 Publisher's PDF, also known as Version of record License (if available): CC BY Link to published version (if available): 10.1371/journal.pgen.1005432 Link to publication record in Explore Bristol Research PDF-document This is the final published version of the article (version of record). It first appeared online via Public Library of Science at http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1005432. Please refer to any applicable terms of use of the publisher. University of Bristol - Explore Bristol Research General rights This document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/red/research-policy/pure/user-guides/ebr-terms/ RESEARCH ARTICLE APLP2 Regulates Refractive Error and Myopia Development in Mice and Humans Andrei V. Tkatchenko1,2☯*, Tatiana V. Tkatchenko1☯, Jeremy A. Guggenheim3☯, Virginie J. M. Verhoeven4,5, Pirro G. Hysi6, Robert Wojciechowski7,8, Pawan Kumar Singh9, Ashok Kumar9,10, Gopal Thinakaran11, Consortium for Refractive Error and Myopia (CREAM)¶, Cathy Williams12 1 Department of Ophthalmology, Columbia University, New York, New York, United States of America, 2 Department of Pathology and Cell Biology, Columbia University, New York, New York, United States of America, 3 School of Optometry & Vision Sciences, Cardiff University, Cardiff, United Kingdom, 4 Department of Ophthalmology, Erasmus Medical Center, Rotterdam, Netherlands, 5 Department of Epidemiology, Erasmus Medical Center, Rotterdam, Netherlands, 6 Department of Twin Research and Genetic Epidemiology, King’s College London School of Medicine, London, United Kingdom, 7 Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America, 8 Statistical Genetics Section, Inherited Disease Research Branch, National Human Genome Research Institute (NIH), Baltimore, Maryland, United States of America, 9 Department of Ophthalmology, Wayne State University, Detroit, Michigan, United States of America, 10 Department of Anatomy and Cell Biology, Wayne State University, Detroit, Michigan, United States of America, 11 Departments of OPEN ACCESS Neurobiology, Neurology, and Pathology, University of Chicago, Chicago, Illinois, United States of America, 12 School of Social and Community Medicine, University of Bristol, Bristol, United Kingdom Citation: Tkatchenko AV, Tkatchenko TV, ☯ Guggenheim JA, Verhoeven VJM, Hysi PG, These authors contributed equally to this work. Wojciechowski R, et al. (2015) APLP2 Regulates ¶ A full list of CREAM members and their affiliations appears in the Supporting Information. * [email protected] Refractive Error and Myopia Development in Mice and Humans. PLoS Genet 11(8): e1005432. doi:10.1371/journal.pgen.1005432 Editor: Gregory S. Barsh, Stanford University School Abstract of Medicine, UNITED STATES Myopia is the most common vision disorder and the leading cause of visual impairment Received: February 10, 2015 worldwide. However, gene variants identified to date explain less than 10% of the variance Accepted: July 7, 2015 in refractive error, leaving the majority of heritability unexplained (“missing heritability”). Published: August 27, 2015 Previously, we reported that expression of APLP2 was strongly associated with myopia in a ’ APLP2 Copyright: © 2015 Tkatchenko et al. This is an open primate model. Here, we found that low-frequency variants near the 5 -end of were access article distributed under the terms of the associated with refractive error in a prospective UK birth cohort (n = 3,819 children; top SNP Creative Commons Attribution License, which permits rs188663068, p = 5.0 × 10−4) and a CREAM consortium panel (n = 45,756 adults; top SNP unrestricted use, distribution, and reproduction in any rs7127037, p = 6.6 × 10−3). These variants showed evidence of differential effect on child- medium, provided the original author and source are credited. hood longitudinal refractive error trajectories depending on time spent reading (gene x time spent reading x age interaction, p = 4.0 × 10−3). Furthermore, Aplp2 knockout mice devel- Data Availability Statement: All relevant data are −4 within the paper and its Supporting Information files oped high degrees of hyperopia (+11.5 ± 2.2 D, p < 1.0 × 10 ) compared to both heterozy- − − except for the gene expression and sequencing data, gous (-0.8 ± 2.0 D, p < 1.0 × 10 4) and wild-type (+0.3 ± 2.2 D, p < 1.0 × 10 4) littermates which were deposited in the Gene Expression and exhibited a dose-dependent reduction in susceptibility to environmentally induced myo- Omnibus (Accession: GSE3300) and GeneBank < −4 (Accession: AY680431-AY680585). pia (F(2, 33) = 191.0, p 1.0 × 10 ). This phenotype was associated with reduced contrast − sensitivity (F(12, 120) = 3.6, p = 1.5 × 10 4) and changes in the electrophysiological proper- Funding: This work was supported by grants Aplp2 APLP2 R21EY018902 and R01EY023839 from the US ties of retinal amacrine cells, which expressed . This work identifies as one of National Institutes of Health (NIH) and research the “missing” myopia genes, demonstrating the importance of a low-frequency gene variant grants from the Midwest Eye-Banks to AVT. The UK in the development of human myopia. It also demonstrates an important role for APLP2 in Medical Research Council and the Wellcome Trust (Grant ref: 102215/2/13/2) and the University of PLOS Genetics | DOI:10.1371/journal.pgen.1005432 August 27, 2015 1/25 APLP2 Regulates Refractive Eye Development in Mice and Humans Bristol provide core support for ALSPAC; this refractive development in mice and humans, suggesting a high level of evolutionary conser- research was supported specifically by the National vation of the signaling pathways underlying refractive eye development. Eye Research Centre, Bristol (SCIAD053); CW is supported by an NIHR Fellowship. JAG was supported by grant Z0GM from the Hong Kong Polytechnic University. GT is supported by grant R01AG019070, RW is supported by grant Author Summary K08EY022943, AK is supported by grant R01EY019888 from NIH. We thank 23andMe for Gene variants identified by GWAS studies to date explain only a small fraction of myopia funding the generation of the ALSPAC GWA data. cases because myopia represents a complex disorder thought to be controlled by dozens or The funders had no role in study design, data even hundreds of genes. The majority of genetic variants underlying myopia seems to be collection and analysis, decision to publish, or preparation of the manuscript. of small effect and/or low frequency, which makes them difficult to identify using classical genetic approaches, such as GWAS, alone. Here, we combined gene expression profiling Competing Interests: The authors have declared in a monkey model of myopia, human GWAS, and a gene-targeted mouse model of myo- that no competing interests exist. pia to identify one of the “missing” myopia genes, APLP2. We found that a low-frequency risk allele of APLP2 confers susceptibility to myopia only in children exposed to large amounts of daily reading, thus, providing an experimental example of the long-hypothe- sized gene-environment interaction between nearwork and genes underlying myopia. Functional analysis of APLP2 using an APLP2 knockout mouse model confirmed func- tional significance of APLP2 in refractive development and implicated a potential role of synaptic transmission at the level of glycinergic amacrine cells of the retina for the devel- opment of myopia. Furthermore, mouse studies revealed that lack of Aplp2 has a dose- dependent suppressive effect on susceptibility to form-deprivation myopia, providing a potential gene-specific target for therapeutic intervention to treat myopia. Introduction Postnatal refractive eye development is a tightly coordinated process whereby visual experience fine-tunes a genetic program of ocular growth towards an optimal match between the optical power of the eye and its axial length in a process called “emmetropization” [1,2]. The emmetro- pization process is regulated by a vision-driven feedback loop in the retina and downstream signaling cascades in other ocular tissues, and normally results in sharp vision (emmetropia). Failure to achieve or maintain emmetropia leads to the development of refractive errors, i.e., farsightedness (hyperopia) or nearsightedness (myopia). Myopia is the most common vision disorder worldwide [3]. The prevalence of myopia has increased from 25% to 44% of the adult population in the United States in the last 30 years [4], and reached more than 80% of young adults in some parts of Asia [5,6]. Myopia negatively affects self-perception, job/activity choices, and ocular health [7–9]. Epidemiological data suggest that common myopia represents a major risk factor for a number of potentially blinding ocular diseases such as cataract, glau- coma, retinal detachment, and myopic maculopathy, which is comparable to the risks associ- ated with hypertension for stroke and myocardial infarction, and represents one of the leading causes of blindness [10–12]. It is estimated that 2.5 billion people (1/3 of the world’s