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2014 | 282 Publications
Pasquale L, Kang J, Wiggs J. Prospects for gene-environment interactions in exfoliation syndrome.. J Glaucoma. 2014;:S64–7.

Complex traits can be triggered by environmental factors in genetically predisposed individuals. The lysyl oxidase-like 1 gene (LOXL1) variants associated with exfoliation syndrome (XFS) are detected in >90% of cases that have been genotyped from sites around the world. Remarkably, roughly 80% of people without XFS also possess these same variants in all populations that have been tested. Nonetheless, the prevalence of XFS varies from ≤0.4% to >20%. These data suggest that other genetic variants, epigenetic modifications, or environmental factors also contribute to XFS. Furthermore, it is possible that environmental factors modify the association between LOXL1 and XFS. Interactions between LOXL1 variants and environmental factors could explain the varying prevalence of XFS seen throughout the world. At the very least, the discovery of the association between LOXL1 variants and XFS has opened the door to the discovery of environmental risk factors for this condition. Candidate gene-environment interactions in XFS will be discussed.

Wiggs J, Pasquale L. Expression and Regulation of LOXL1 and Elastin-related Genes in Eyes With Exfoliation Syndrome.. J Glaucoma. 2014;:S62–3.

Variants in LOXL1 are significantly associated with exfoliation syndrome (XFS), however the impact of the associated variants on disease development is not yet understood. Initially the associated missense changes, R141L and G153D, were considered to be pathogenic alleles. Flipping of the risk allele in certain populations for both missense variants provided strong evidence that these missense changes are not biologically significant and suggest that other LOXL1 variant(s), in linkage disequilibrium with these missense variants, predispose to exfoliation syndrome by affecting gene expression or protein function. Several lines of evidence support dysregulation of LOXL1 gene expression as a contributing factor to disease development. First, in the German population the R141L (rs1048661) risk allele reduced LOXL1 expression by 20%. Second, haplotype analysis identified a risk haplotype that includes including R141L, G153D, as well as a LOXL1 promoter region variant previously shown to reduce gene expression (rs16958477). Third, the LOXL1 risk haplotype influences gene expression induced by disease-associated factors TGF-B1, oxidative stress, UV light and hypoxia. Finally, a LOXL1 null mouse has some features of XFS suggesting that decreased enzyme activity contributes to predisposition to the disease. Collectively, these results suggest that dysregulation of LOXL1 expression is a contributing factor to exfoliation disease development.

Zhu R, Cho KS, Chen DF, Yang L. Ephrin-A2 and -A3 are negative regulators of the regenerative potential of Möller cells. Chin Med J (Engl). 2014;127(19):3438–42.
BACKGROUND: In a previous study, we demonstrated that ephrin-A2 and -A3 negatively regulate the growth of neural progenitor cells in the central nervous system. Adult mice deficient in ephrin-A2 and -A3 (A2(-/-)A3(-/-)) displayed active ongoing neurogenesis throughout the brain, and mice deficient in ephrin-A3 alone showed increased proliferation of ciliary epithelium derived retinal stem cells. This study aimed to detect that the increase in proliferation and neurogenic potential of Müller cells is influenced by the absence of ephrin-A2 and -A3. METHODS: We assessed the retinal and Müller cell expression of ephrin-As and their receptor and neural progenitor cell markers by immunostaining and real-time PCR. We cultured purified primary Müller cells derived from wild-type and A2(-/-)A3(-/-) mice in a defined culture medium that enables trans-differentiation of Müller cells into retinal neurons. To evaluate proliferating Müller cells in vivo, we injected 5'-ethylnyl-2'-deoxiuridine (EdU) intraperitoneally to adult mice. RESULTS: Expression of ephrin-A2/A3 and their receptor EphA4 were detected in the retinas of adult mice, with EphA4 expression particularly enriched in Müller cells. Müller cells of A2(-/-)A3(-/-) mice exhibited significantly elevated expression of retinal progenitor cell markers, Pax6 and Chx10, when compared with those from wild-type mice. Moreover, a higher percentage of Müller cells of A2(-/-)A3(-/-) mice trans-differentiated and became recoverin+ and β-III-tublin+ in the culture than those from wild type mice. Strikingly, an increased number of EdU+ retinal cells was detected in the retinas of adult A2(-/-)A3(-/-) mice as compared with wild-type mice. CONCLUSIONS: Ephrin-A2 and -A3 are negative regulators of the proliferative and neurogenic potentials of Müller cells. Manipulating ephrin-A signaling may thus represent a novel strategy for stimulating neuroregeneration from endogenous progenitors to participate in retinal repair in case of disease or damage.
Hysi P, Cheng CY, Springelkamp H, Macgregor S, Bailey JC, Wojciechowski R, Vitart V, Nag A, Hewitt A, Höhn R, Venturini C, Mirshahi A, Ramdas W, Thorleifsson G, Vithana E, Khor CC, Stefansson A, Liao J, Haines J, Amin N, Wang YX, Wild P, Ozel A, Li J, Fleck B, Zeller T, Staffieri S, Teo YY, Cuellar-Partida G, Luo X, Allingham R, Richards J, Senft A, Karssen L, Zheng Y, Bellenguez C, Xu L, Iglesias A, Wilson J, Kang J, Leeuwen E, Jonsson V, Thorsteinsdottir U, Despriet D, Ennis S, Moroi S, Martin N, Jansonius N, Yazar S, Tai ES, Amouyel P, Kirwan J, Koolwijk L, Hauser M, Jonasson F, Leo P, Loomis S, Fogarty R, Rivadeneira F, Kearns L, Lackner K, Jong P, Simpson C, Pennell C, Oostra B, Uitterlinden A, Saw SM, Lotery A, Bailey-Wilson J, Hofman A, Vingerling J, Maubaret C, Pfeiffer N, Wolfs R, Lemij H, Young T, Pasquale L, Delcourt C, Spector T, Klaver C, Small K, Burdon K, Stefansson K, Wong TY, BMES GWAS Group, NEIGHBORHOOD Consortium, Wellcome Trust Case Control Consortium 2, Viswanathan A, Mackey D, Craig J, Wiggs J, Duijn C, Hammond C, Aung T. Genome-wide analysis of multi-ancestry cohorts identifies new loci influencing intraocular pressure and susceptibility to glaucoma.. Nat Genet. 2014;46(10):1126–30.

Elevated intraocular pressure (IOP) is an important risk factor in developing glaucoma, and variability in IOP might herald glaucomatous development or progression. We report the results of a genome-wide association study meta-analysis of 18 population cohorts from the International Glaucoma Genetics Consortium (IGGC), comprising 35,296 multi-ancestry participants for IOP. We confirm genetic association of known loci for IOP and primary open-angle glaucoma (POAG) and identify four new IOP-associated loci located on chromosome 3q25.31 within the FNDC3B gene (P = 4.19 × 10(-8) for rs6445055), two on chromosome 9 (P = 2.80 × 10(-11) for rs2472493 near ABCA1 and P = 6.39 × 10(-11) for rs8176693 within ABO) and one on chromosome 11p11.2 (best P = 1.04 × 10(-11) for rs747782). Separate meta-analyses of 4 independent POAG cohorts, totaling 4,284 cases and 95,560 controls, showed that 3 of these loci for IOP were also associated with POAG.

Gharahkhani P, Burdon K, Fogarty R, Sharma S, Hewitt A, Martin S, Law M, Cremin K, Bailey JC, Loomis S, Pasquale L, Haines J, Hauser M, Viswanathan A, McGuffin P, Topouzis F, Foster P, Graham S, Casson R, Chehade M, White A, Zhou T, Souzeau E, Landers J, Fitzgerald J, Klebe S, Ruddle J, Goldberg I, Healey P, Wellcome Trust Case Control Consortium 2, NEIGHBORHOOD Consortium, Mills R, Wang JJ, Montgomery G, Martin N, Radford-Smith G, Whiteman D, Brown M, Wiggs J, Mackey D, Mitchell P, Macgregor S, Craig J. Common variants near ABCA1, AFAP1 and GMDS confer risk of primary open-angle glaucoma.. Nat Genet. 2014;46(10):1120–5.

Primary open-angle glaucoma (POAG) is a major cause of irreversible blindness worldwide. We performed a genome-wide association study in an Australian discovery cohort comprising 1,155 cases with advanced POAG and 1,992 controls. We investigated the association of the top SNPs from the discovery stage in two Australian replication cohorts (932 cases and 6,862 controls total) and two US replication cohorts (2,616 cases and 2,634 controls total). Meta-analysis of all cohorts identified three loci newly associated with development of POAG. These loci are located upstream of ABCA1 (rs2472493[G], odds ratio (OR) = 1.31, P = 2.1 × 10(-19)), within AFAP1 (rs4619890[G], OR = 1.20, P = 7.0 × 10(-10)) and within GMDS (rs11969985[G], OR = 1.31, P = 7.7 × 10(-10)). Using RT-PCR and immunolabeling, we show that these genes are expressed within human retina, optic nerve and trabecular meshwork and that ABCA1 and AFAP1 are also expressed in retinal ganglion cells.

Sanderson J, Dartt DA, Trinkaus-Randall V, Pintor J, Civan M, Delamere N, Fletcher E, Salt T, Grosche A, Mitchell C. Purines in the eye: recent evidence for the physiological and pathological role of purines in the RPE, retinal neurons, astrocytes, Müller cells, lens, trabecular meshwork, cornea and lacrimal gland. Exp Eye Res. 2014;127:270–9.
This review highlights recent findings that describ how purines modulate the physiological and pathophysiological responses of ocular tissues. For example, in lacrimal glands the cross-talk between P2X7 receptors and both M3 muscarinic receptors and α1D-adrenergic receptors can influence tear secretion. In the cornea, purines lead to post-translational modification of EGFR and structural proteins that participate in wound repair in the epithelium and influence the expression of matrix proteins in the stroma. Purines act at receptors on both the trabecular meshwork and ciliary epithelium to modulate intraocular pressure (IOP); ATP-release pathways of inflow and outflow cells differ, possibly permitting differential modulation of adenosine delivery. Modulators of trabecular meshwork cell ATP release include cell volume, stretch, extracellular Ca(2+) concentration, oxidation state, actin remodeling and possibly endogenous cardiotonic steroids. In the lens, osmotic stress leads to ATP release following TRPV4 activation upstream of hemichannel opening. In the anterior eye, diadenosine polyphosphates such as Ap4A act at P2 receptors to modulate the rate and composition of tear secretion, impact corneal wound healing and lower IOP. The Gq11-coupled P2Y1-receptor contributes to volume control in Müller cells and thus the retina. P2X receptors are expressed in neurons in the inner and outer retina and contribute to visual processing as well as the demise of retinal ganglion cells. In RPE cells, the balance between extracellular ATP and adenosine may modulate lysosomal pH and the rate of lipofuscin formation. In optic nerve head astrocytes, mechanosensitive ATP release via pannexin hemichannels, coupled with stretch-dependent upregulation of pannexins, provides a mechanism for ATP signaling in chronic glaucoma. With so many receptors linked to divergent functions throughout the eye, ensuring the transmitters remain local and stimulation is restricted to the intended target may be a key issue in understanding how physiological signaling becomes pathological in ocular disease.
Zinn E, Vandenberghe L. Adeno-associated virus: fit to serve.. Curr Opin Virol. 2014;8C:90–97.

Adeno-associated virus (AAV) is a helper-dependent parvovirus which has not been linked with human disease. This aspect, in combination with its broad cell and tissue tropism, and limited viral host response has made it an attractive vector system for gene therapy. The viral protein capsid, the primary interface with the host, is the main determinant for these phenotypes, is highly variable, and is most subject to pressures during replication. Here, we explore the evolutionary path of AAV and other parvoviruses in respect to these phenotypes, as well as directed evolution and engineering strategies that have exploited the lessons learned from natural selection in order to address remaining limitations of AAV as a therapeutic gene transfer platform.

Kazlauskas A. Plakophilin-2 promotes activation of epidermal growth factor receptor.. Mol Cell Biol. 2014;34(20):3778–9.

While growth factor-driven dimerization of receptor tyrosine kinases (RTKs) is a simple and intuitive mechanism of activating RTKs, K.-I. Arimoto et al. (Mol. Cell. Biol. 34:3843-3854, 2014, doi:10.1128/MCB.00758-14) describe a novel means of promoting the activity of RTKs. Namely, plakophilin-2 (PKP2) associates with the epidermal growth factor receptor (EGFR) and enhances its ligand-dependent and ligand-independent activity. This discovery suggests that antagonizing PKP2 may be a new therapeutic opportunity to combat tumors in which activation of EGFR contributes to pathogenesis.

Farkas M, Lew D, Sousa M, Bujakowska K, Chatagnon J, Bhattacharya S, Pierce E, Nandrot E. Mutations in pre-mRNA processing factors 3, 8, and 31 cause dysfunction of the retinal pigment epithelium.. Am J Pathol. 2014;184(10):2641–52.

Mutations in the ubiquitously expressed pre-mRNA processing factors 3, 8, and 31 (PRPF3, PRPF8, and PRPF31) cause nonsyndromic dominant retinitis pigmentosa in humans, an inherited retinal degeneration. It is unclear what mechanisms, or which cell types of the retina, are affected. Transgenic mice with the human mutations in these genes display late-onset morphological changes in the retinal pigment epithelium (RPE). To determine whether the observed morphological changes are preceded by abnormal RPE function, we investigated its phagocytic function in Prpf3(T494M/T494M), Prpf8(H2309P/H2309P), and Prpf31(+/-) mice. We observe decreased phagocytosis in primary RPE cultures from mutant mice, and this is replicated by shRNA-mediated knockdown of PRPF31 in human ARPE-19 cells. The diurnal rhythmicity of phagocytosis is almost lost, indicated by the marked attenuation of the phagocytic burst 2 hours after light onset. The strength of adhesion between RPE apical microvilli and photoreceptor outer segments also declined during peak adhesion in all mutants. In all models, at least one of the receptors involved in binding and internalization of shed photoreceptor outer segments was subjected to changes in localization. Although the mechanism underlying these changes in RPE function is yet to be elucidated, these data are consistent with the mouse RPE being the primary cell affected by mutations in the RNA splicing factors, and these changes occur at an early age.

Valdez C, Arboleda-Velasquez J, Amarnani D, Kim L, D’Amore P. Retinal microangiopathy in a mouse model of inducible mural cell loss. Am J Pathol. 2014;184(10):2618–26.
Diabetes can lead to vision loss because of progressive degeneration of the neurovascular unit in the retina, a condition known as diabetic retinopathy. In its early stages, the pathology is characterized by microangiopathies, including microaneurysms, microhemorrhages, and nerve layer infarcts known as cotton-wool spots. Analyses of postmortem human retinal tissue and retinas from animal models indicate that degeneration of the pericytes, which constitute the outer layer of capillaries, is an early event in diabetic retinopathy; however, the relative contribution of specific cellular components to the pathobiology of diabetic retinopathy remains to be defined. We investigated the phenotypic consequences of pericyte death on retinal microvascular integrity by using nondiabetic mice conditionally expressing a diphtheria toxin receptor in mural cells. Five days after administering diphtheria toxin in these adult mice, changes were observed in the retinal vasculature that were similar to those observed in diabetes, including microaneurysms and increased vascular permeability, suggesting that pericyte cell loss is sufficient to trigger retinal microvascular degeneration. Therapies aimed at preventing or delaying pericyte dropout may avoid or attenuate the retinal microangiopathy associated with diabetes.
Song D, Grieco S, Li Y, Hunter A, Chu S, Zhao L, Song Y, DeAngelis R, Shi LY, Liu Q, Pierce E, Nishina P, Lambris J, Dunaief J. A murine RP1 missense mutation causes protein mislocalization and slowly progressive photoreceptor degeneration. Am J Pathol. 2014;184(10):2721–9.
Mutations in the RP1 gene can cause retinitis pigmentosa. We identified a spontaneous L66P mutation caused by two adjacent point mutations in the Rp1 gene in a colony of C57BL/6J mice. Mice homozygous for the L66P mutation exhibited slow, progressive photoreceptor degeneration throughout their lifespan. Optical coherence tomography imaging found abnormal photoreceptor reflectivity at 1 month of age. Histology found shortening and disorganization of the photoreceptor inner and outer segments and progressive thinning of the outer nuclear layer. Electroretinogram a- and b-wave amplitudes were decreased with age. Western blot analysis found that the quantity and size of the mutated retinitis pigmentosa 1 (RP1) protein were normal. However, immunohistochemistry found that the mutant Rp1 protein partially mislocalized to the transition zone of the shortened axonemes. This mutation disrupted colocalization with cytoplasmic microtubules in vitro. In conclusion, the L66P mutation in the first doublecortin domain of the Rp1 gene impairs Rp1 protein localization and function, leading to abnormalities in photoreceptor outer segment structure and progressive photoreceptor degeneration. This is the first missense mutation in Rp1 shown to cause retinal degeneration. It provides a unique, slowly progressive photoreceptor degeneration model that mirrors the slow degeneration kinetics in most patients with retinitis pigmentosa.
Rahimi Darabad R, Suzuki T, Richards S, Jakobiec F, Zakka F, Barabino S, Sullivan D. Does estrogen deficiency cause lacrimal gland inflammation and aqueous-deficient dry eye in mice?. Exp Eye Res. 2014;127:153–60.

Researchers have proposed that estrogen deficiency will lead to a Sjögren's syndrome (SjS)-like lacrimal gland inflammation, aqueous tear deficiency and dry eye. The purpose of this study was to determine whether this proposal is correct. Lacrimal glands were obtained from adult, age-matched wild type (WT) and aromatase knockout (ArKO) mice, in which estrogen synthesis is completely eliminated. Tissues were also obtained from autoimmune MRL/Mp-lpr/lpr (MRL/lpr) mice as inflammation controls. Tear volumes in WT and ArKO mice were measured and glands were processed for molecular biological and histological evaluation. Our results demonstrate that estrogen absence does not lead to a SjS-like inflammation in lacrimal tissue or to an aqueous-deficient dry eye. There was no upregulation of genes associated with inflammatory pathways in lacrimal glands of male or female ArKO mice. Such inflammatory activity was prominent in autoimmune MRL/lpr tissues. We also found no evidence of inflammation in lacrimal gland tissue sections of estrogen-deficient mice, and tear volumes of ArKO males were actually increased as compared to those WT controls. Interestingly, our study did show that estrogen absence influences the expression of thousands of lacrimal gland genes, and that this impact is sex- and genotype-specific. Our findings demonstrate that estrogen absence is not a risk factor for the development of SjS-like lacrimal gland inflammation or for aqueous-deficient dry eye in mice.

Dartt DA, Masli S. Conjunctival epithelial and goblet cell function in chronic inflammation and ocular allergic inflammation.. Curr Opin Allergy Clin Immunol. 2014;14(5):464–70.

PURPOSE OF REVIEW: Although conjunctival goblet cells are a major cell type in ocular mucosa, their responses during ocular allergy are largely unexplored. This review summarizes the recent findings that provide key insights into the mechanisms by which their function and survival are altered during chronic inflammatory responses, including ocular allergy. RECENT FINDINGS: Conjunctiva represents a major component of the ocular mucosa that harbors specialized lymphoid tissue. Exposure of mucin-secreting goblet cells to allergic and inflammatory mediators released by the local innate and adaptive immune cells modulates proliferation, secretory function, and cell survival. Allergic mediators like histamine, leukotrienes, and prostaglandins directly stimulate goblet cell mucin secretion and consistently increase goblet cell proliferation. Goblet cell mucin secretion is also detectable in a murine model of allergic conjunctivitis. Additionally, primary goblet cell cultures allow evaluation of various inflammatory cytokines with respect to changes in goblet cell mucin secretion, proliferation, and apoptosis. These findings in combination with the preclinical mouse models help understand the goblet cell responses and their modulation during chronic inflammatory diseases, including ocular allergy. SUMMARY: Recent findings related to conjunctival goblet cells provide the basis for novel therapeutic approaches, involving modulation of goblet cell mucin production, to improve treatment of ocular allergies.

Jakobiec F, Rashid A, Lane K, Kazim M. Granulomatous dacryoadenitis in regional enteritis (crohn disease).. Am J Ophthalmol. 2014;158(4):838–844.e1.

PURPOSE: To evaluate the clinical and immunopathologic features of 2 patients with bilateral dacryoadenitis associated with regional enteritis. DESIGN: Retrospective, clinicopathologic study. METHODS: Clinical records, photographs, and imaging studies were reviewed and microscopic sections of lacrimal gland biopsy samples were critically re-evaluated. The microscopic slides were stained with hematoxylin and eosin, special stains for organisms, and a range of immunohistochemical biomarkers, including CD3, CD4, CD5, CD8, CD20, CD68, CD138, CD1a, and immunoglobulins Ig G, IgG4, and IgA. RESULTS: Both patients were young women with a well-established diagnosis of regional enteritis. Histopathologic examination of biopsy samples disclosed moderate intraparenchymal fibrosis and lymphoplasmacytic infiltrates without lymphoid follicles. Small to medium intraparenchymal, noncaseating granulomas lacking multinucleated giant cells and, in 1 patient, CD68-positive and CD1a-negative palisading granulomas in widened interlobular fibrous septa were detected. Vasculitis and IgG4 plasma cells were not observed. Additional immunohistochemical studies revealed that CD8 T lymphocytes (suppressor or cytotoxic subset) predominated over CD4-positive T lymphocytes (helper cells) surrounding the necrobiotic foci and were intermixed with the CD68-positive histiocytes in the absence of CD20 B lymphocytes. Special stains for organisms demonstrated negative results. CONCLUSIONS: Dacryoadenitis is the rarest form of ocular adnexal involvement in regional enteritis, which affects the orbit far more frequently than ulcerative colitis. It is a granulomatous process with the possibility of palisading necrobiotic foci. In contrast, ulcerative colitis causes an interstitial lymphocytic and nongranulomatous myositis. Sarcoidosis, Wegener granulomatosis, and pseudorheumatoid nodules must be ruled out. Treatment options entail a wide variety of agents with selection based on empirical considerations and tailored to the patient's symptoms.

Werdich X, Jakobiec F, Curtin H, Fay A. A clinical, radiologic, and immunopathologic study of five periorbital intraosseous cavernous vascular malformations.. Am J Ophthalmol. 2014;158(4):816–826.e1.

PURPOSE: To correlate the clinical, radiographic, histopathologic, and immunohistochemical features of 5 primary periorbital intraosseous cavernous vascular malformations. DESIGN: Retrospective interventional case series. METHODS: Clinical and operative records and radiographic images were reviewed. Histopathologic slides were evaluated with hematoxylin-eosin, trichrome, and elastin stains. Immunohistochemical studies were performed with a spectrum of monoclonal antibodies directed at antigens of vascular cells. RESULTS: Three men and 2 women ranged in age from 36 to 64 years. Vision was unaffected and there was no proptosis or globe displacement. The slow-growing lesions measured 13-25 mm in greatest diameter (mean 16.4 mm). Computed tomographic studies revealed that 2 lesions were situated in the maxillary bone, 2 in the frontal, and 1 in the zygoma, all anteriorly and with circumscribed, lucent, honeycombed, or sunburst characteristics. Histopathologically the lesions were composed of cavernous or telangiectatic channels; 1 showed advanced fibrotic vascular involution. Immunohistochemistry demonstrated CD31/34 positivity for vascular endothelium and D2-40 negativity for lymphatic endothelium. A typically thin mural myofibroblastic cuff was smooth muscle actin positive, weakly calponin positive, and desmin negative. Glucose transporter-1 and Ki-67 were negative in the endothelium. CONCLUSIONS: Intraosseous vascular lesions resemble orbital cavernous venous malformations (not true hemangiomas), except that their vascular walls are thinner owing to the constraints imposed by neighboring bone spicules, which limit the amount of interstitium from which mural myofibroblasts can be recruited. The bony trabeculae conferred the honeycomb or sunburst appearances observed radiographically. En bloc excision of these lesions was successful and avoided complications (mean follow-up, 46 months).

Samsom M, Morrison S, Masala N, Sullivan B, Sullivan D, Sheardown H, Schmidt T. Characterization of full-length recombinant human Proteoglycan 4 as an ocular surface boundary lubricant. Exp Eye Res. 2014;127:14–9.
Proteoglycan 4 (PRG4, or lubricin) is a lubricating mucin-like glycoprotein recently discovered at the ocular surface, where it functions as a boundary lubricant and appears to play a protective role. Recent technological advances have enabled abundant expression of full-length recombinant human PRG4 (rhPRG4). The objectives of this study were to 1) biochemically characterize the gross structure and glycosylations of full-length rhPRG4, and 2) assess the ocular surface boundary lubricating ability of rhPRG4 at both human cornea-eyelid and human cornea-polydimethylsiloxane (PDMS) biointerfaces. rhPRG4 expressed by a Chinese hamster ovary cell line was characterized and compared to native bovine PRG4 by SDS-PAGE western blotting, and protein identity was assessed by tandem mass spectrometry (MS/MS). Human corneas were articulated against PDMS or human eyelids, at effective sliding velocities of 0.3-30 mm/s under physiological loads of ∼15 kPa, to assess and compare the ocular lubricating ability of rhPRG4 to PRG4. Samples were tested serially in PRG4, rhPRG4 (both 300 μg/ml), then saline. Western blotting indicated that rhPRG4 had immunoreactivity at the appropriate apparent molecular weight, and possessed O-linked glycosylation consistent with that of PRG4. rhPRG4 protein identity was confirmed by MS/MS. Both PRG4 and rhPRG4 significantly, and similarly, reduced friction compared to saline at both human cornea - PDMS and human cornea-eyelid biointerfaces. In conclusion, the rhPRG4 studied here demonstrated appropriate higher order structure, O-linked glycosylations, and ocular surface boundary lubricating. Purified rhPRG4 may have clinical utility as a topical treatment of dry eye disease or contact lens biomaterial coating to promote more comfortable wear.
Sandberg M, Pearce E, Harper S, Weigel-DiFranco C, Hart L, Rosner B, Berson E. The relationship of central foveal thickness to urinary iodine concentration in retinitis pigmentosa with or without cystoid macular edema.. JAMA Ophthalmol. 2014;132(10):1209–14.

IMPORTANCE: Current treatments for cystoid macular edema (CME) in retinitis pigmentosa (RP) are not always effective, may lead to adverse effects, and may not restore visual acuity. The present research lays the rationale for evaluating whether an iodine supplement could reduce CME in RP. OBJECTIVE: To determine whether central foveal thickness (CFT) in the presence of CME is related to dietary iodine intake inferred from urinary iodine concentration (UIC) in nonsmoking adults with RP. DESIGN, SETTING, AND PARTICIPANTS: We performed a cross-sectional observational study of 212 nonsmoking patients aged 18 to 69 years referred to our institution for RP with visual acuity of no worse than 20/200 in at least 1 eye. EXPOSURE: Retinitis pigmentosa with or without CME. MAIN OUTCOMES AND MEASURES: With the eye as the unit of analysis, the relationship of log CFT measured by optical coherence tomography to UIC measured from multiple spot samples and represented as a 3-level classification variable (<100, 100-199, and ≥200 µg/L), assigning greater weight to patients with more reliable UIC estimates. RESULTS: Analyses were limited to 199 patients after excluding 11 who failed to return urine samples for measuring UIC and 2 outliers for UIC. Of the 199 patients, 36.2% had CME in 1 or both eyes. Although log CFT was inversely related to UIC based on findings from all eyes (P = .02), regression of log CFT on UIC separately for eyes with and without CME showed a strong inverse significant relationship for the former group (P < .001) and no significant relationship for the latter group (P = .66) as tested. For the eyes with CME, CFT ranged from a geometric mean of 267 µm for a median UIC of less than 100 µg/L to a geometric mean of 172 µm for a median UIC of 200 µg/L or greater. In contrast, we found no significant association between CME prevalence and UIC based on the entire sample as tested (odds ratio, 1.01 [95% CI, 0.38-2.67]; P = .99). CONCLUSIONS AND RELEVANCE: A higher UIC in nonsmoking adults with RP was significantly associated with less central foveal swelling in eyes with CME. Additional study is required to determine whether an iodine supplement can limit or reduce the extent of CME in patients with RP.

Ratnapriya R, Zhan X, Fariss R, Branham K, Zipprer D, Chakarova C, Sergeev Y, Campos M, Othman M, Friedman J, Maminishkis A, Waseem N, Brooks M, Rajasimha H, Edwards A, Lotery A, Klein B, Truitt B, Li B, Schaumberg D, Morgan D, Morrison M, Souied E, Tsironi E, Grassmann F, Fishman G, Silvestri G, Scholl H, Kim I, Ramke J, Tuo J, Merriam J, Merriam J, Park KH, Olson L, Farrer L, Johnson M, Peachey N, Lathrop M, Baron R, Igo R, Klein R, Hagstrom S, Kamatani Y, Martin T, Jiang Y, Conley Y, Sahel JA, Zack D, Chan CC, Pericak-Vance M, Jacobson S, Gorin M, Klein M, Allikmets R, Iyengar S, Weber B, Haines J, Léveillard T, Deangelis M, Stambolian D, Weeks D, Bhattacharya S, Chew E, Heckenlively J, Abecasis G, Swaroop A. Rare and common variants in extracellular matrix gene Fibrillin 2 (FBN2) are associated with macular degeneration.. Hum Mol Genet. 2014;23(21):5827–37.

Neurodegenerative diseases affecting the macula constitute a major cause of incurable vision loss and exhibit considerable clinical and genetic heterogeneity, from early-onset monogenic disease to multifactorial late-onset age-related macular degeneration (AMD). As part of our continued efforts to define genetic causes of macular degeneration, we performed whole exome sequencing in four individuals of a two-generation family with autosomal dominant maculopathy and identified a rare variant p.Glu1144Lys in Fibrillin 2 (FBN2), a glycoprotein of the elastin-rich extracellular matrix (ECM). Sanger sequencing validated the segregation of this variant in the complete pedigree, including two additional affected and one unaffected individual. Sequencing of 192 maculopathy patients revealed additional rare variants, predicted to disrupt FBN2 function. We then undertook additional studies to explore the relationship of FBN2 to macular disease. We show that FBN2 localizes to Bruch's membrane and its expression appears to be reduced in aging and AMD eyes, prompting us to examine its relationship with AMD. We detect suggestive association of a common FBN2 non-synonymous variant, rs154001 (p.Val965Ile) with AMD in 10 337 cases and 11 174 controls (OR = 1.10; P-value = 3.79 × 10(-5)). Thus, it appears that rare and common variants in a single gene-FBN2-can contribute to Mendelian and complex forms of macular degeneration. Our studies provide genetic evidence for a key role of elastin microfibers and Bruch's membrane in maintaining blood-retina homeostasis and establish the importance of studying orphan diseases for understanding more common clinical phenotypes.

Cattaneo Z, Lega C, Gardelli C, Merabet L, Cela-Conde C, Nadal M. The role of prefrontal and parietal cortices in esthetic appreciation of representational and abstract art: a TMS study. Neuroimage. 2014;99:443–50.
To explain the biological foundations of art appreciation is to explain one of our species' distinctive traits. Previous neuroimaging and electrophysiological studies have pointed to the prefrontal and the parietal cortex as two critical regions mediating esthetic appreciation of visual art. In this study, we applied transcranial magnetic stimulation (TMS) over the left prefrontal cortex and the right posterior parietal cortex while participants were evaluating whether they liked, and by how much, a particular painting. By depolarizing cell membranes in the targeted regions, TMS transiently interferes with the activity of specific cortical areas, which allows clarifying their role in a given task. Our results show that both regions play a fundamental role in mediating esthetic appreciation. Critically though, the effects of TMS varied depending on the type of art considered (i.e. representational vs. abstract) and on participants' a-priori inclination toward one or the other.
Silva P, Diala P, Hamam R, Arrigg P, Shah S, Murtha T, Schlossman D, Cavallerano J, Sun J, Aiello L. Visual outcomes from pars plana vitrectomy versus combined pars plana vitrectomy, phacoemulsification, and intraocular lens implantation in patients with diabetes.. Retina. 2014;34(10):1960–8.

PURPOSE: To compare visual acuity outcomes and diabetic retinopathy progression after pars plana vitrectomy (PPV) versus combined pars plana vitrectomy and phacoemulsification (PPVCE) in patients with diabetes. METHODS: Retrospective review of 222 consecutive diabetic patients undergoing PPV or PPVCE. RESULTS: A total of 251 eyes of 222 patients were evaluated (PPV = 122, PPVCE = 129). Four-year follow-up was 64% (161 eyes). Overall, patients undergoing PPVCE had better preoperative visual acuity (PPVCE = 20/80, PPV = 20/160, P = 0.03). At 4-year follow-up, visual acuity improved (PPV = +22, PPVCE = +11 letters) compared with baseline in both groups. After correcting for baseline differences in visual acuity, no statistically significant difference in final visual acuity was observed (PPVCE = 20/32, PPV = 20/50, P = 0.09). Results did not differ substantially by surgical indication (vitreous hemorrhage, traction retinal detachment, epiretinal membrane, and/or diabetic macular edema). Cataract progression occurred in 64%, and cataract surgery was performed in 39% of phakic eyes undergoing PPV. Rates of diabetic retinopathy progression, vitreous hemorrhage, and retinal detachment were not statistically different. Neovascular glaucoma developed in 2 patients (2%) after PPV and 6 patients (8%) after PPVCE (P = 0.07). CONCLUSION: In diabetic patients, equivalent visual acuity improvement over 4 years was observed after PPV or PPVCE. Visual outcomes and retinopathy progression rates were not significantly different after either intervention, suggesting that PPVCE may be appropriate when indicated in patients with diabetes.

Leidl M, Choi C, Syed Z, Melki S. Intraocular pressure fluctuation and glaucoma progression: what do we know?. Br J Ophthalmol. 2014;98(10):1315–1319.

While mean intraocular pressure (IOP) has long been known to correlate with glaucomatous damage, the role of IOP fluctuation is less clearly defined. There is extensive evidence in the literature for and against the value of short-term and long-term IOP fluctuation in the evaluation and prognosis of patients with glaucoma. We present here the arguments made by both sides, as well as a discussion of the pitfalls of prior research and potential directions for future studies. Until a reliable method is developed that allows for constant IOP monitoring, many variables will continue to hinder us from drawing adequate conclusions regarding the significance of IOP variation.

Arboleda-Velasquez J, Primo V, Graham M, James A, Manent J, D’Amore P. Notch signaling functions in retinal pericyte survival. Invest Ophthalmol Vis Sci. 2014;55(8):5191–9.
PURPOSE: Pericytes, the vascular cells that constitute the outer layer of capillaries, have been shown to have a crucial role in vascular development and stability. Loss of pericytes precedes endothelial cell dysfunction and vascular degeneration in small-vessel diseases, including diabetic retinopathy. Despite their clinical relevance, the cellular pathways controlling survival of retinal pericytes remain largely uncharacterized. Therefore, we investigated the role of Notch signaling, a master regulator of cell fate decisions, in retinal pericyte survival. METHODS: A coculture system of ligand-dependent Notch signaling was developed using primary cultured retinal pericytes and a mesenchymal cell line derived from an inducible mouse model expressing the Delta-like 1 Notch ligand. This model was used to examine the effect of Notch activity on pericyte survival using quantitative PCR (qPCR) and a light-induced cell death assay. The effect of Notch gain- and loss-of-function was analyzed in monocultures of retinal pericytes using antibody arrays to interrogate the expression of apoptosis-related proteins. RESULTS: Primary cultured retinal pericytes differentially expressed key molecules of the Notch pathway and displayed strong expression of canonical Notch/RBPJK (recombination signal-binding protein 1 for J-kappa) downstream targets. A gene expression screen using gain- and loss-of-function approaches identified genes relevant to cell survival as downstream targets of Notch activity in retinal pericytes. Ligand-mediated Notch activity protected retinal pericytes from light-induced cell death. CONCLUSIONS: Our results have identified signature genes downstream of Notch activity in retinal pericytes and suggest that tight regulation of Notch signaling is crucial for pericyte survival.
Arnoldner M, Kheirkhah A, Jakobiec F, Durand M, Hamrah P. Successful treatment of Paecilomyces lilacinus keratitis with oral posaconazole. Cornea. 2014;33(7):747–9.
PURPOSE: To report a case of successful medical treatment with oral posaconazole in refractory fungal keratitis caused by Paecilomyces lilacinus. METHODS: Case report. RESULTS: A 57-year-old male, soft contact lens wearer presented with irritation, pain, photophobia, and reduced vision. Slit-lamp examination showed a large corneal epithelial defect with a peripheral infiltrate. The patient did not improve on fortified topical antibiotics. After the diagnosis of P. lilacinus fungal keratitis, oral voriconazole and topical antifungal therapy were started. Despite antifungal therapy, progressive disease required therapeutic penetrating keratoplasty. Postoperatively, because of clinical signs of recurrence and in vivo confocal microscopy findings of presumed hyphae in the cornea, intracameral miconazole was injected and oral posaconazole was started. The patient improved and demonstrated no hyphae 6 weeks after starting posaconazole. When posaconazole was stopped, the cornea remained clear with excellent acuity. However, because of acute graft rejection 2 months after stopping posaconazole, keratoprosthesis was implanted, with no evidence of infection at surgery or during the 3.5-year follow-up. CONCLUSIONS: To the best of our knowledge, this is the first report on the use of oral posaconazole for Paecilomyces keratitis. Posaconazole might be indicated in the treatment of refractory Paecilomyces keratitis that is resistant to conventional therapy.