Publications

2018

Han S, Qiu C, Lee K, Jung JH, Peli E. Word recognition: re-thinking prosthetic vision evaluation. J Neural Eng. 2018;15(5):055003.
OBJECTIVE: Evaluations of vision prostheses and sensory substitution devices have frequently relied on repeated training and then testing with the same small set of items. These multiple forced-choice tasks produced above chance performance in blind users, but it is unclear if the observed performance represents restoration of vision that transfers to novel, untrained items. APPROACH: Here, we tested the generalizability of the forced-choice paradigm on discrimination of low-resolution word images. Extensive visual training was conducted with the same 10 words used in previous BrainPort tongue stimulation studies. The performance on these 10 words and an additional 50 words was measured before and after the training sessions. MAIN RESULTS: The results revealed minimal performance improvement with the untrained words, demonstrating instead pattern discrimination limited mostly to the trained words. SIGNIFICANCE: These findings highlight the need to reconsider current evaluation practices, in particular, the use of forced-choice paradigms with a few highly trained items. While appropriate for measuring the performance thresholds in acuity or contrast sensitivity of a functioning visual system, performance on such tasks cannot be taken to indicate restored spatial pattern vision.
Hua J, Inomata T, Chen Y, Foulsham W, Stevenson W, Shiang T, Bluestone J, Dana R. Pathological conversion of regulatory T cells is associated with loss of allotolerance. Sci Rep. 2018;8(1):7059.
CD4CD25Foxp3 Regulatory T cells (Tregs) play a critical role in immune tolerance. The plasticity and functional adaptability of Tregs in an inflammatory microenvironment has been demonstrated in autoimmunity. Here, using a double transgenic mouse model that permits Foxp3 lineage tracing, we investigated the phenotypic plasticity of Foxp3 Tregs in a well-characterized murine model of corneal transplantation. In order to subvert the normal immune privilege of the cornea and foster an inflammatory milieu, host mice were exposed to desiccating stress prior to transplantation. Treg frequencies and function were decreased following desiccating stress, and this corresponded to decreased graft survival. A fraction of Tregs converted to IL-17 or IFNγ 'exFoxp3' T cells that were phenotypically indistinguishable from effector Th17 or Th1 cells, respectively. We investigated how Foxp3 expression is modulated in different Treg subsets, demonstrating that neuropilin-1 peripherally-derived Tregs are particularly susceptible to conversion to IL-17/IFNγ exFoxp3 cells in response to cues from their microenvironment. Finally, we show that IL-6 and IL-23 are implicated in the conversion of Tregs to exFoxp3 cells. This report demonstrates that the pathological conversion of Tregs contributes to the loss of corneal immune privilege.
Iglesias A, Mishra A, Vitart V, Bykhovskaya Y, Höhn R, Springelkamp H, Cuellar-Partida G, Gharahkhani P, Bailey JC, Willoughby C, Li X, Yazar S, Nag A, Khawaja A, Polašek O, Siscovick D, Mitchell P, Tham YC, Haines J, Kearns L, Hayward C, Shi Y, Leeuwen E, Taylor K, Blue Mountains Eye Study—GWAS group, Bonnemaijer P, Rotter J, Martin N, Zeller T, Mills R, Staffieri S, Jonas J, Schmidtmann I, Boutin T, Kang J, Lucas S, Wong TY, Beutel M, Wilson J, NEIGHBORHOOD Consortium, Wellcome Trust Case Control Consortium 2 (WTCCC2), Uitterlinden A, Vithana E, Foster P, Hysi P, Hewitt A, Khor CC, Pasquale L, Montgomery G, Klaver C, Aung T, Pfeiffer N, Mackey D, Hammond C, Cheng CY, Craig J, Rabinowitz Y, Wiggs J, Burdon K, Duijn C, Macgregor S. Cross-ancestry genome-wide association analysis of corneal thickness strengthens link between complex and Mendelian eye diseases. Nat Commun. 2018;9(1):1864.
Central corneal thickness (CCT) is a highly heritable trait associated with complex eye diseases such as keratoconus and glaucoma. We perform a genome-wide association meta-analysis of CCT and identify 19 novel regions. In addition to adding support for known connective tissue-related pathways, pathway analyses uncover previously unreported gene sets. Remarkably, >20% of the CCT-loci are near or within Mendelian disorder genes. These included FBN1, ADAMTS2 and TGFB2 which associate with connective tissue disorders (Marfan, Ehlers-Danlos and Loeys-Dietz syndromes), and the LUM-DCN-KERA gene complex involved in myopia, corneal dystrophies and cornea plana. Using index CCT-increasing variants, we find a significant inverse correlation in effect sizes between CCT and keratoconus (r = -0.62, P = 5.30 × 10) but not between CCT and primary open-angle glaucoma (r = -0.17, P = 0.2). Our findings provide evidence for shared genetic influences between CCT and keratoconus, and implicate candidate genes acting in collagen and extracellular matrix regulation.
Johnston T, Van Tyne D, Chen R, Fawzi N, Kwon B, Kelso M, Gilmore M, Mylonakis E. Propyl-5-hydroxy-3-methyl-1-phenyl-1H-pyrazole-4-carbodithioate (HMPC): a new bacteriostatic agent against methicillin-resistant Staphylococcus aureus. Sci Rep. 2018;8(1):7062.
The emergence of Staphylococcus aureus strains resistant to 'last resort' antibiotics compels the development of new antimicrobials against this important human pathogen. We found that propyl 5-hydroxy-3-methyl-1-phenyl-1H-pyrazole-4-carbodithioate (HMPC) shows bacteriostatic activity against S. aureus (MIC = 4 μg/ml) and rescues Caenorhabditis elegans from S. aureus infection. Whole-genome sequencing of S. aureus mutants resistant to the compound, along with screening of a S. aureus promoter-lux reporter array, were used to explore possible mechanisms of action. All mutants resistant to HMPC acquired missense mutations at distinct codon positions in the global transcriptional regulator mgrA, followed by secondary mutations in the phosphatidylglycerol lysyltransferase fmtC/mprF. The S. aureus promoter-lux array treated with HMPC displayed a luminescence profile that was unique but showed similarity to DNA-damaging agents and/or DNA replication inhibitors. Overall, HMPC is a new anti-staphylococcal compound that appears to act via an unknown mechanism linked to the global transcriptional regulator MgrA.
Kang JH, Rosner B, Wiggs J, Pasquale L. Sex hormone levels and risk of primary open-angle glaucoma in postmenopausal women. Menopause. 2018;25(10):1116–1123.
OBJECTIVE: We evaluated the relation of prediagnostic sex hormone levels in postmenopausal women with primary open-angle glaucoma (POAG) and intraocular pressure (IOP). METHODS: Among postmenopausal participants of the Nurses' Health Study, POAG cases (n = 189; diagnosed 1990-2008) and controls (n = 189) were matched on age, fasting status, and postmenopausal hormone use at blood draw (1989-1990). Plasma concentrations of estrone sulfate, estradiol, testosterone, sex hormone binding globulin, and dehydroepiandrosterone sulfate were assessed. The primary outcome was POAG; in secondary analyses, among cases only, we evaluated maximum untreated IOP at diagnosis. Multivariable-adjusted logistic/multiple linear regression models were used to evaluate tertiles (Ts) of biomarker levels and the two outcomes, adjusting for various potential confounders. RESULTS: We observed no significant associations of estrone, estradiol, sex hormone binding globulin, or dehydroepiandrosterone sulfate with POAG risk or with maximum IOP at glaucoma diagnosis among cases. Suggestive significant associations were observed with highest testosterone and POAG risk (T3 vs T1 multivariable-adjusted odds ratio 1.84; 95% confidence interval 1.02, 3.33; P trend 0.10). Similarly, for maximum IOP at diagnosis among cases only (mean 8 years after blood draw), higher testosterone was significantly associated with higher IOP (multivariable-adjusted difference in IOP T3 vs T1 2.17 mm Hg; 95% confidence interval 0.34, 3.99; P trend 0.02). CONCLUSIONS: Overall, plasma sex hormone levels in postmenopausal women were not associated with POAG risk; however, a trend of higher testosterone levels being associated with higher POAG risk and higher IOP at diagnosis was observed and needs confirmation.
Khawaja A, Cooke Bailey J, Wareham N, Scott R, Simcoe M, Igo R, Song Y, Wojciechowski R, Cheng CY, Khaw P, Pasquale L, Haines J, Foster P, Wiggs J, Hammond C, Hysi P, Consortium UBEV, NEIGHBORHOOD Consortium. Genome-wide analyses identify 68 new loci associated with intraocular pressure and improve risk prediction for primary open-angle glaucoma. Nat Genet. 2018;50(6):778–782.
Glaucoma is the leading cause of irreversible blindness globally . Despite its gravity, the disease is frequently undiagnosed in the community . Raised intraocular pressure (IOP) is the most important risk factor for primary open-angle glaucoma (POAG). Here we present a meta-analysis of 139,555 European participants, which identified 112 genomic loci associated with IOP, 68 of which are novel. These loci suggest a strong role for angiopoietin-receptor tyrosine kinase signaling, lipid metabolism, mitochondrial function and developmental processes underlying risk for elevated IOP. In addition, 48 of these loci were nominally associated with glaucoma in an independent cohort, 14 of which were significant at a Bonferroni-corrected threshold. Regression-based glaucoma-prediction models had an area under the receiver operating characteristic curve (AUROC) of 0.76 in US NEIGHBORHOOD study participants and 0.74 in independent glaucoma cases from the UK Biobank. Genetic-prediction models for POAG offer an opportunity to target screening and timely therapy to individuals most at risk.
Lee A, Karamichos D, Onochie O, Hutcheon A, Rich C, Zieske J, Trinkaus-Randall V. Hypoxia modulates the development of a corneal stromal matrix model. Exp Eye Res. 2018;170:127–137.
Deposition of matrix proteins during development and repair is critical to the transparency of the cornea. While many cells respond to a hypoxic state that can occur in a tumor, the cornea is exposed to hypoxia during development prior to eyelid opening and during the diurnal sleep cycle where oxygen levels can drop from 21% to 8%. In this study, we used 2 three-dimensional (3-D) models to examine how stromal cells respond to periods of acute hypoxic states. The first model, a stromal construct model, is a 3-D stroma-like construct that consists of human corneal fibroblasts (HCFs) stimulated by a stable form of ascorbate for 1, 2, and 4 weeks to self-assemble their own extracellular matrix. The second model, a corneal organ culture model, is a corneal wound-healing model, which consists of wounded adult rat corneas that were removed and placed in culture to heal. Both models were exposed to either normoxic or hypoxic conditions for varying time periods, and the expression and/or localization of matrix proteins was assessed. No significant changes were detected in Type V collagen, which is associated with Type I collagen fibrils; however, significant changes were detected in the expression of both the small leucine-rich repeating proteoglycans and the larger heparan sulfate proteoglycan, perlecan. Also, hypoxia decreased both the number of Cuprolinic blue-positive glycosaminoglycan chains along collagen fibrils and Sulfatase 1, which modulates the effect of heparan sulfate by removing the 6-O-sulfate groups. In the stromal construct model, alterations were seen in fibronectin, similar to those that occur in development and after injury. These changes in fibronectin after injury were accompanied by changes in proteoglycans. Together these findings indicate that acute hypoxic changes alter the physiology of the cornea, and these models will allow us to manipulate the conditions in the extracellular environment in order to study corneal development and trauma.
PURPOSE: To report a simple, highly effective technique of simultaneous transconjunctival repair of upper and lower eyelid retraction in patients with thyroid eye disease (TED). METHODS: A retrospective interventional case review was conducted on 22 eyes of 19 TED patients. The lower eyelid was recessed with placement of a tarsoconjunctival spacer graft harvested from the upper eyelid. The upper eyelid was then recessed through the conjunctival incision used to harvest the tarsal graft. A temporary tarsorrhaphy was placed for 5-7 days. The postoperative outcome was assessed by measuring the margin reflex distance of the upper eyelid (MRD1), inferior scleral show (ISS), and lagophthalmos. RESULTS: The absolute change in MRD1 ranged from 0 to 5 mm with an average of 1.86 ± 1.34 mm. The absolute change in ISS ranged from 0 to 2 mm with an average of 1.3 ± 0.49 mm. One patient had postoperative lagophthalmos and 17 of 19 had improvement in their ocular surface exposure symptoms. None of the patients' grafts were observed to undergo absorption during the postoperative course. CONCLUSIONS: This technique of harvesting a free tarsoconjunctival graft from the upper eyelid as a posterior spacer for the lower while simultaneously recessing the upper eyelid through the same incision is an effective and durable method of correcting eyelid retraction in TED.
Maurer A, Pacouret S, Cepeda Diaz AK, Blake J, Andres-Mateos E, Vandenberghe L. The Assembly-Activating Protein Promotes Stability and Interactions between AAV’s Viral Proteins to Nucleate Capsid Assembly. Cell Rep. 2018;23(6):1817–1830.
The adeno-associated virus (AAV) vector is a preferred delivery platform for in vivo gene therapy. Natural and engineered variations of the AAV capsid affect a plurality of phenotypes relevant to gene therapy, including vector production and host tropism. Fundamental to these aspects is the mechanism of AAV capsid assembly. Here, the role of the viral co-factor assembly-activating protein (AAP) was evaluated in 12 naturally occurring AAVs and 9 putative ancestral capsid intermediates. The results demonstrate increased capsid protein stability and VP-VP interactions in the presence of AAP. The capsid's dependence on AAP can be partly overcome by strengthening interactions between monomers within the assembly, as illustrated by the transfer of a minimal motif defined by a phenotype-to-phylogeny mapping method. These findings suggest that the emergence of AAP within the Dependovirus genus relaxes structural constraints on AAV assembly in favor of increasing the degrees of freedom for the capsid to evolve.
McDermott A, Baidouri H, Woodward A, Kam W, Liu Y, Chen X, Ziemanski J, Vistisen K, Hazlett L, Nichols K, Argüeso P, Sullivan D. Short Tandem Repeat (STR) Profiles of Commonly Used Human Ocular Surface Cell Lines. Curr Eye Res. 2018;43(9):1097–1101.
PURPOSE: The purpose of this study is to establish the short tandem repeat (STR) profiles of several human cell lines commonly used in ocular surface research. MATERIALS AND METHODS: Independently DNA was extracted from multiple passages of three human corneal epithelial cell lines, two human conjunctival epithelial cell lines and one meibomian gland cell line, from different laboratories actively involved in ocular surface research. The samples were then subjected to STR analysis on a fee-for-service basis in an academic setting and the data compared against that in available databases. RESULTS: The STR profiles for the human corneal epithelial cells were different among the three cell lines studied and for each line the profiles were identical across the samples provided by three laboratories. Profiles for the human conjunctival epithelial cells were different among the two cell lines studied. Profiles for the meibomian gland cell line were identical across the samples provided by three laboratories. No samples were contaminated by elements of other cell lines such as HeLa. CONCLUSIONS: This comprehensive study provides verification of STR profiles for commonly used human ocular surface cell lines that can now be used as a reference by others in the field to authenticate the cell lines in use in their own laboratories.