OFCD syndrome and extraembryonic defects are revealed by conditional mutation of the Polycomb-group repressive complex 1.1 (PRC1.1) gene BCOR.

BCOR is a critical regulator of human development. Heterozygous mutations of BCOR in females cause the X-linked developmental disorder Oculofaciocardiodental syndrome (OFCD), and hemizygous mutations of BCOR in males cause gestational lethality. BCOR associates with Polycomb group proteins to form one subfamily of the diverse Polycomb repressive complex 1 (PRC1) complexes, designated PRC1.1. Currently there is limited understanding of differing developmental roles of the various PRC1 complexes. We therefore generated a conditional exon 9-10 knockout Bcor allele and a transgenic conditional Bcor expression allele and used these to define multiple roles of Bcor, and by implication PRC1.1, in mouse development. Females heterozygous for Bcor exhibiting mosaic expression due to the X-linkage of the gene showed reduced postnatal viability and had OFCD-like defects. By contrast, Bcor hemizygosity in the entire male embryo resulted in embryonic lethality by E9.5. We further dissected the roles of Bcor, focusing on some of the tissues affected in OFCD through use of cell type specific Cre alleles. Mutation of Bcor in neural crest cells caused cleft palate, shortening of the mandible and tympanic bone, ectopic salivary glands and abnormal tongue musculature. We found that defects in the mandibular region, rather than in the palate itself, led to palatal clefting. Mutation of Bcor in hindlimb progenitor cells of the lateral mesoderm resulted in 2/3 syndactyly. Mutation of Bcor in Isl1-expressing lineages that contribute to the heart caused defects including persistent truncus arteriosus, ventricular septal defect and fetal lethality. Mutation of Bcor in extraembryonic lineages resulted in placental defects and midgestation lethality. Ubiquitous over expression of transgenic Bcor isoform A during development resulted in embryonic defects and midgestation lethality. The defects we have found in Bcor mutants provide insights into the etiology of the OFCD syndrome and how BCOR-containing PRC1 complexes function in development.

iSyTE 2.0: a database for expression-based gene discovery in the eye.

Although successful in identifying new cataract-linked genes, the previous version of the database iSyTE (integrated Systems Tool for Eye gene discovery) was based on expression information on just three mouse lens stages and was functionally limited to visualization by only UCSC-Genome Browser tracks. To increase its efficacy, here we provide an enhanced iSyTE version 2.0 (URL: http://research.bioinformatics.udel.edu/iSyTE) based on well-curated, comprehensive genome-level lens expression data as a one-stop portal for the effective visualization and analysis of candidate genes in lens development and disease. iSyTE 2.0 includes all publicly available lens Affymetrix and Illumina microarray datasets representing a broad range of embryonic and postnatal stages from wild-type and specific gene-perturbation mouse mutants with eye defects. Further, we developed a new user-friendly web interface for direct access and cogent visualization of the curated expression data, which supports convenient searches and a range of downstream analyses. The utility of these new iSyTE 2.0 features is illustrated through examples of established genes associated with lens development and pathobiology, which serve as tutorials for its application by the end-user. iSyTE 2.0 will facilitate the prioritization of eye development and disease-linked candidate genes in studies involving transcriptomics or next-generation sequencing data, linkage analysis and GWAS approaches.

The endocytic recycling regulatory protein EHD1 Is required for ocular lens development.

The C-terminal Eps15 homology domain-containing (EHD) proteins play a key role in endocytic recycling, a fundamental cellular process that ensures the return of endocytosed membrane components and receptors back to the cell surface. To define the in vivo biological functions of EHD1, we have generated Ehd1 knockout mice and previously reported a requirement of EHD1 for spermatogenesis. Here, we show that approximately 56% of the Ehd1-null mice displayed gross ocular abnormalities, including anophthalmia, aphakia, microphthalmia and congenital cataracts. Histological characterization of ocular abnormalities showed pleiotropic defects that include a smaller or absent lens, persistence of lens stalk and hyaloid vasculature, and deformed optic cups. To test whether these profound ocular defects resulted from the loss of EHD1 in the lens or in non-lenticular tissues, we deleted the Ehd1 gene selectively in the presumptive lens ectoderm using Le-Cre. Conditional Ehd1 deletion in the lens resulted in developmental defects that included thin epithelial layers, small lenses and absence of corneal endothelium. Ehd1 deletion in the lens also resulted in reduced lens epithelial proliferation, survival and expression of junctional proteins E-cadherin and ZO-1. Finally, Le-Cre-mediated deletion of Ehd1 in the lens led to defects in corneal endothelial differentiation. Taken together, these data reveal a unique role for EHD1 in early lens development and suggest a previously unknown link between the endocytic recycling pathway and regulation of key developmental processes including proliferation, differentiation and morphogenesis.

[Embryological aspects of clinical presentations of congenital lens and vitreous anomalies]. / Émbriologicheskie aspekty klinicheskikh proiavlenii vrozhdennykh izmenenii khrustalika i steklovidnogo tela.

This report gives a general overview of embryological features of the human eye. Key literature sources published during the last century on evaluation of congenital changes in the vitreous body and identification of signs of its 'underdevelopment' in certain types of congenital cataracts have been studied. The said changes were analyzed in terms of general pathology of the human body as well as local morphological manifestations. According to the authors, such an approach justifies the need for comparison of clinical manifestations of congenital lens and vitreous changes with possible embryonic defects.

Deletion of autophagy-related 5 (Atg5) and Pik3c3 genes in the lens causes cataract independent of programmed organelle degradation.

The lens of the eye is composed of fiber cells, which differentiate from epithelial cells and undergo programmed organelle degradation during terminal differentiation. Although autophagy, a major intracellular degradation system, is constitutively active in these cells, its physiological role has remained unclear. We have previously shown that Atg5-dependent macroautophagy is not necessary for lens organelle degradation, at least during the embryonic period. Here, we generated lens-specific Atg5 knock-out mice and showed that Atg5 is not required for lens organelle degradation at any period of life. However, deletion of Atg5 in the lens results in age-related cataract, which is accompanied by accumulation of polyubiquitinated and oxidized proteins, p62, and insoluble crystallins, suggesting a defect in intracellular quality control. We also produced lens-specific Pik3c3 knock-out mice to elucidate the possible involvement of Atg5-independent alternative autophagy, which is proposed to be dependent on Pik3c3 (also known as Vps34), in lens organelle degradation. Deletion of Pik3c3 in the lens does not affect lens organelle degradation, but it leads to congenital cataract and a defect in lens development after birth likely due to an impairment of the endocytic pathway. Taken together, these results suggest that clearance of lens organelles is independent of macroautophagy. These findings also clarify the physiological role of Atg5 and Pik3c3 in quality control and development of the lens, respectively.

Rubella cataract in vitro: Sensitive period of the developing human lens.

The clinically known sensitive period of rubella cataract was studied in vitro by infecting 79 human eye rudiments from embryos aged 4-10 wk with rubella virus. The course of the infection was followed by histological and indirect immunofluorescence methods. Of the rudiments, 12 pairs were in the lens placode or open-lens-vesicle stage, 40 already had closed lens vesicles and in another 27 closed-stage pairs an incision was made in the lens capsule before infection to allow the virus to enter the lens. Uninfected controls differentiated well in vitro for 4-6 wk. The eye rudiments infected in the open-lens-vesicle stage showed lens fiber destruction and viral antigens within the lens. No damage or viral antigens were detected in rudiments infected in the closed stage unless the lens capsule was incisedmwhen this was done, however, fiber damage ensued and viral antigens appeared. The lens capsule was concluded to form a protective barrier around the sensirive fibers at the time of closure of the lens vesicle, confirming the earlier hypothesis and clinical findings.

Identification of a novel locus for a USH3 like syndrome combined with congenital cataract.

Usher syndrome (USH) is the most common genetic disease that causes both deafness and blindness. USH is divided into three types, USH1, USH2 and USH3, depending on the age of onset, the course of the disease, and on the degree of vestibular dysfunction. By homozygosity mapping of a consanguineous Danish family of Dutch descent, we have identified a novel locus for a rare USH3-like syndrome. The affected family members have a unique association of retinitis pigmentosa, progressive hearing impairment, vestibular dysfunction, and congenital cataract. The phenotype is similar, but not identical to that of USH3 patients, as congenital cataract has not been reported for USH3. By homozygosity mapping, we identified a 7.3 Mb locus on chromosome 15q22.2-23 with a maximum multipoint LOD score of 2.0. The locus partially overlaps with the USH1 locus, USH1H, a novel unnamed USH2 locus, and the non-syndromic deafness locus DFNB48.

Intrauterine Cataract Diagnosis and Follow-up

In this article, we report a 21-gestational-week fetus diagnosed with congenital cataract by ultrasonography. The parents decided to terminate the pregnancy and asked for examination of the fetus. An amniocentesis was performed for fetal karyotyping. After termination of the pregnancy, fetal autopsy was conducted. Whole exome sequencing (Trio-WES) analysis of the mother and father was done from peripheral blood samples. In the pathologic autopsy report, bilateral anterior and posterior subcapsular cataracts were confirmed. Whole exome sequencing analysis revealed a previously unreported class 3 variant of uncertain significance (c755A>G [P.Lys252Arg]) of the CRYBB1 gene, which is associated with congenital cataract, that was homozygous in the fetus and heterozygous in the parents. The obtained result is consistent with a genetic diagnosis of isolated autosomal recessive cataract.

Prenatal diagnosis of fetal cataract: case report and review of the literature.

OBJECTIVES: To report a case of prenatally diagnosed fetal cataract and conduct a systematic review of previously reported cases. METHODS: Review of the literature based mainly on Pubmed search using specific keywords in order to list cataract causes diagnosed prenatally and in early childhood, isolated or associated with microphthalmia. RESULTS AND DISCUSSION: A differential diagnosis list and specific prenatal diagnosis testing are suggested in order to offer the best management of this rare fetal condition.

Deletion of Seventeen Amino Acids at the C-Terminal End of Aquaporin 0 Causes Distortion Aberration and Cataract in the Lenses of AQP0ΔC/ΔC Mice.

Purpose: Investigate the effects of the absence of 17 amino acids at the C-terminal end of Aquaporin 0 (AQP0) on lens transparency, focusing property, and homeostasis. Methods: A knockin (KI) mouse model (AQP0ΔC/ΔC) was developed to express AQP0 only as the end-cleaved form in the lens. For this, AQP0 was genetically engineered as C-terminally end-cleaved with amino acids 1 to 246, instead of the full length 1 to 263 of the wild type (WT). After verifying the KI integration into the genome and its expression, the mouse model was bred for several generations. AQP0 KI homozygous (AQP0ΔC/ΔC) and heterozygous (AQP0+/ΔC) lenses were imaged and analyzed at different developmental stages for transparency. Correspondingly, aberrations in the lens were characterized using the standard metal grid focusing method. Data were compared with age-matched WT, AQP0 knockout (AQP0-/-), and AQP0 heterozygous (AQP0+/-) lenses. Results: AQP0ΔC/ΔC lenses were transparent throughout the embryonic development and until postnatal day 15 (P15) in contrast to age-matched AQP0-/- lenses, which developed cataract at embryonic stage itself. However, there was distortion aberration in AQP0ΔC/ΔC lens at P5; after P15, cataract began to develop and progressed faster surpassing that of age-matched AQP0-/- lenses. AQP0+/ΔC lenses were transparent even at the age of 1 year in contrast to AQP0+/- lenses; however, there was distortion aberration starting at P15. Conclusions: A specific distribution profile of intact and end-cleaved AQP0 from the outer cortex to the inner nucleus is required in the lens for establishing refractive index gradient to enable proper focusing without aberrations and for maintaining transparency.

Autosomal dominant congenital cataract in a Libyan Jewish family: cosegregation with a reciprocal chromosomal translocation [t(3;5)(p22.3; p15.1)].

PURPOSE: To describe a Jewish family of Libyan ancestry in which autosomal dominant congenital cataract segregates with an apparently balanced reciprocal chromosomal translocation. METHODS: Detailed family history and clinical data were recorded. Cytogenetic studies were performed on 13 family members. RESULTS: Embryonal cataracts cosegregated through three generations with a balanced chromosomal translocation [t(3;5)(p22.3; p15.1)] while the unbalanced translocation product, 46,XY,-5,+der(5)t(3:5)(p22:p15.1), had multiple congenital anomalies without cataracts. CONCLUSIONS: These observations suggest that an altered function of a gene at one of the translocation breakpoints on chromosome 3p22.3 or 5p15.1 is causally related to cataract development.

[Corneal anomalies in murine trisomy 16]. / Minoranomalien der Hornhaut bei der murinen Trisomie 16.

BACKGROUND: The prevalence of human Down's syndrome is about 1:700. Investigations using animal models are therefore of clinical relevance for understanding its etiopathogenesis. No corneal changes have been reported with transgenic murine trisomy 16. METHODS: A total of 20 fetal mice (n=40 eyes) with experimentally induced trisomy 16 were investigated from day 18 of pregnancy in order to determine whether visible developmental disorders of the cornea occur. All specimen were investigated microscopically in serial sections. RESULTS: In addition to disturbances in systemic development, the transgenic mouse fetuses showed high rates of malformation of the eyes. Developmental and differentiation disorders of the corneal epithelial cell layers and structural disturbances of the corneal parenchyma were found. Our findings are the first demonstration of developmental disorders of the cornea in mouse fetuses with trisomy 16. These minor anomalies of the cornea could well have resulted in keratoconus if the animals had survived. CONCLUSIONS: Our findings in transgenic mouse fetuses with trisomy 16 correspond to the clinical pattern of Down's syndrome in humans. Disturbed development of lids and lenses have a high prevalence, whereas corneal hypoplasia is found less often.

Effect of astaxanthin on cataract formation induced by glucocorticoids in the chick embryo.

PURPOSE: To examine whether astaxanthin (AST) prevent the cataract formation induced by glucocorticoid in chick embryo. MATERIALS AND METHODS: Hydrocortisone hemisuccinate sodium (HC) (0.5 µmol/egg) was administered directly into the air chamber in the egg shell of chick embryo day 15. The eggs were then kept in an incubator at same conditions and administered 100 µL of 50 (HC + AST50 group), 80 (HC + AST80 group), 100 (HC + AST100 group) mg/mL of AST solutions dissolved in dimethyl sulfoxide (DMSO) 3 h after administration of HC. In addition, non-HC treated group (treated with physiological saline without HC and 100 µL of DMSO), HC-alone group (treated with 0.5 µmol of HC and 100 µL of DMSO), and AST100 group (treated with physiological saline without HC and 100 µL of DMSO) were also incorporated. After 48 h of treatment, lenses were removed from embryo and classified into five stages according to developed opacity. The amounts of reduced glutathione in the lenses and the blood glucose levels were measured. RESULTS: The average scores of lens opacitiy were 2.63 ± 1.02 nmol/lens (HC-alone), 2.78 ± 0.97 nmol/lens (HC + AST50), 2.22 ± 1.20 nmol/lens (HC + AST80) and 1.84 ± 0.83 nmol/lens (HC + AST100; p < 0.05), respectively. Administration of AST decreased the lens opacity dose-dependently. The amounts of reduced glutathione in lenses were 11.6 ± 2.8 nmol/lens (HC-alone), 11.3 ± 2.7 nmol/lens (HC + AST50), 13.4 ± 2.4 nmol/lens (HC + AST80) and 13.7 ± 3.1 nmol/lens (HC + AST100; p < 0.05), respectively. Higher levels of AST prevented loss of reduced glutathione from the lens. CONCLUSION: These findings support that AST protects glucocorticoid-induced cataract in chick embryo.

Developmental ocular abnormalities in rats with X-ray--induced cataract mutation.

Prenatal and early postnatal devpelopment of eyes of Wistar rats with X-ray-induced cataract mutation was assessed histologically, to determine the events leading to cataract formation. A significant phenomenon appeared to be retinal folding, which occurred regularly at 14 to 15 days of gestation and might have pushed the lens against the cornea. A corneal reaction with the lens was indicated by corneal adhesions to the lens, seen frequently during and shortly after the period of retinal folding, and could have stimulated the epithelial hyperplasia that leads invariably to anterior polar cataract in these animals. Changes in the lens fiber cells, which could have been generated by the epithelial hyperplasia, included the sporadic detachment of newly developing fibers from the lens epithelium and the eventual swelling of the anterior ends of fibers still attached to the epithelium. The detached fibers became fusiform and developed postnatally into posterior, suture-associated vacuoles. Anterior uveitis was noted postnatally in some eyes and probably contributed to the subsequent development of the cataract. The results are discussed in the light of congenital anterior polar cataract formation reported in humans and other animals.

The role of Src family kinases in cortical cataract formation.

PURPOSE: The goal of this study was to determine the role of Src family kinases (SFKs) in the development of lens cataract. This question was particularly significant, because these tyrosine kinases mediate the stress pathways known to lead to cataract formation. The experiments were focused on whether the inhibition of SFK activity suppresses the formation of lens opacities. METHODS: A whole-lens culture system was developed, in which cortical opacities formed within 5 days, in embryonic day (E)10 lenses grown in medium containing 10% fetal bovine serum. SFK activity was blocked in the cultured lenses by growth in the presence of the SFK-specific inhibitor PP1. Control cultures were grown in medium without inhibitor or in the presence of PP3, the inactive analogue of PP1. Lenses were cultured for 10 days, observed, and photographed daily. Opacification was quantified with image-analysis software. Tissue architecture was determined after hematoxylin and eosin staining and cellular organization by fluorescent localization of filamentous actin with fluorescein-conjugated phalloidin. RESULTS: Almost all lenses in the control cultures developed cortical opacities covering approximately 50% of the lens area by day 10. Similar to control cultures, PP1-treated lenses showed mild posterior opacities during the first 5 days in culture, but then became strikingly transparent. Only 7% of the PP1-treated lenses showed development of cortical cataract, and the average area of opacity was just 0.5% by culture day 10. In all cultured lenses, even in the presence of the PP1 inhibitor, the bow region of the lens extended to the posterior pole, and distribution of nuclei from the posterior pole toward the anterior aspects of the lens suggested that newly added fiber cells were misdirected. However, neither this feature, nor the presence of vacuoles appeared to correlate with the development of opacity in the cultured lenses. Instead, the lens opacities appeared to result from gross abnormalities in the shape and organization of cells in the equatorial and cortical fiber zones, as observed by F-actin staining. Culturing the lenses in the presence of the SFK inhibitor prevented these lens cell aberrations as well as the development of lens opacity. CONCLUSIONS: The formation of cataract can involve activation of SFK-mediated pathway(s) leading to disorganization of developing lens fiber cells, and inhibiting these tyrosine kinases blocks cataract progression.

Coordinate signaling by Src and p38 kinases in the induction of cortical cataracts.

PURPOSE: The goals of this study were to determine whether MAP kinase signaling pathways play a role in the formation of lens cataracts and to examine the potential signaling relationship between Src and MAP kinases in signaling the induction of lens opacities. METHODS: Embryonic day (E)10 chick lenses were cultured in Medium 199 containing 10% fetal bovine serum. The activation state of Src kinases and the MAP kinases extracellular signal-regulated protein kinase (ERK), c-jun N-terminal kinase (JNK), and p38 in the lens epithelium was determined over a time course from 10 minutes to 10 days in culture by immunoblot analysis. Src kinase activation was suppressed by exposure to the Src family kinase-specific inhibitor PP1. To examine the role of specific MAP kinases in the development of lens opacities, lenses were grown for 10 days in the presence or absence of inhibitors of ERK (U0126), JNK (SP600125), and p38 (SB203580). Lenses were observed and photographed daily, and the degree of opacification was quantified by using image-analysis software. RESULTS: Within a short time after placing embryonic lenses in culture conditions that induce the formation of cataracts, there occurred a great increase in the activation state of the MAP kinase ERK. Activation of ERK was both rapid and transient. No activation of the MAP kinase JNK was observed in the cataract cultures beyond that which occurred in normal lens epithelium, even though JNK activation is often linked to the cellular response to stress. In contrast, although p38 activation was barely detected in the normal embryonic lens, this stress-activated protein kinase exhibited a robust activation in cataract cultures that was sustained throughout the culture period. Studies conducted to map the cataract signaling pathways indicate that the p38 MAP kinase functions upstream of the Src kinase. To analyze the potential role of ERK, JNK, and p38 in cataract induction, lenses were cultured in the presence of specific MAP kinase inhibitors. Although the inhibitors of ERK and JNK did not interfere with the formation of cataract, p38 inhibitors blocked the development of lens opacities with an efficacy similar to that of the Src kinase inhibitor PP1. CONCLUSIONS: Activation of both Src and p38 kinases lead to the induction of cataract.

Is month of birth associated with cataract in later life?

BACKGROUND: It has been suggested that season of birth might influence the susceptibility to cataract in later life. METHODS: This hypothesis was investigated using data pooled from two case-control studies carried out in Oxfordshire. RESULTS/CONCLUSION: The results showed no relation between month or season of birth and cataract in later life in an English population.

Glucocorticoid-induced cataract of developing chick embryo as a screening model for anticataract agents.

In order to develop an effective screening model for anticataract agents, we examined the age dependence of cataract induction by glucocorticoid in developing chick embryos. Hydrocortisone sodium succinate (0.25 mumol) was administered to chick embryos on day 15 (15-day-old) and cataract formation was examined 48 hr later. Administration earlier than on day 13 or later than on day 15 was a little or ineffective. These results indicate that the formation of glucocorticoid-induced cataract in developing chick embryos depends on developing stages. The embryos treated with hydrocortisone sodium succinate on day 15 decreased GSH amount in the lens, approximately 50% of the control in 48hr. However, the embryos treated at other ages, in which cataract was not induced, showed little or no decrease of GSH. The cataract formation in chick embryos appeared to depend on structure of steroid and was due to biological activities of glucocorticoids. Since cataract is easily produced in a reproducible manner with high incidence by glucocorticoid, our chick embryo model will be a valuable model system for screening anticataract agents.

Synthesis of monoesters of pyrroloquinoline quinone and imidazopyrroloquinoline, and radical scavenging activities using electron spin resonance in vitro and pharmacological activity in vivo.

Monoesters with the ester groups at C-2 of pyrroloquinoline quinone (PQQ) and C-9 of imidazopyrroloquinoline (IPQ) were synthesized, and radical scavenging activities of coenzyme PQQ, IPQ compounds synthesized from PQQ and various amino acids, and monoesters of PQQ and IPQ were studied in vitro and in vivo. PQQ and PQQ monoesters had strong radical scavenging activity using ESR in in vitro experiments. The IC50 value for superoxide (O2-) was from 1 to 6 x 10(-8) M and that for the hydroxy radical (.OH) was from 4 to 6 x 10(-5) M. IPQ compounds and IPQ monoesters also showed radical scavenging activity. These compounds prevented injury during in vivo experiments, such as hydrocortisone-induced cataracts, endotoxin shock and CCl4-induced liver injury (isolated hepatocytes and rats). Especially, the monoesters of PQQ and IPQ prevented liver injury in rats equally by oral or intraperitoneal administration. These results suggest that PQQ functions as a radical scavenging factor in addition to being a cofactor of quinoprotein enzymes, and monoesters with the ester groups at C-2 of PQQ and C-9 of IPQ are developed as treatment or preventive medicine for disease caused by radical compounds on the basis of strong radical scavenging activities, absorbability into cells, toxicity, safety and chemical stability.

Inhibition in rat of development of in utero galactose-induced cataract by an aldose reductase inhibitor--a light microscopic study.

Aldose reductase inhibitors (ARIs) have been known to be effective in preventing galactose cataract by blocking the polyol pathway. Because the rat congenital galactose cataract is also induced by accumulated polyol, the effect of an ARI in the induction of congenital galactose cataract was investigated. Pregnant rats were placed on a 30% galactose diet. On fetal day 16, 17, 18 or 20, the fetal lenses were examined by light microscope. Lenses from newborn rats with mothers fed galactose diet until gestational day 16, 17, 18 or 20 and then given a galactose diet containing ARI were also examined. The fetal lenses obtained from galactose-fed mother rats on day 16 of gestation were morphologically similar to those of controls. On day 17, the experimental lenses displayed vacuolated areas. The lenses of newborn rats with mothers given an ARI diet after gestational day 16 showed no morphological changes, while a few small vacuoles were observed in the lens of rats with mothers given the ARI diet after day 17, 18 or 20 of gestation. ARI inhibited the rat congenital galactose cataract even when the drug was given to the mother rat during a late stage of pregnancy.