Diagnostic utility of in vivo confocal microscopy in Acanthamoeba keratitis following corneal crosslinking.

Acanthamoeba keratitis (AK) is a rare but potentially sight-threatening complication of corneal collagen crosslinking (CXL) for keratoconus. In this report, we describe an early adolescent male who underwent routine CXL for progressive keratoconus in his left eye. Preprocedural left visual acuity (VA) was 6/9. At day 5 postprocedure, multifocal corneal infiltrates were identified. Corneal scrape, bandage contact lens cultures and herpetic and Acanthamoeba PCR were negative. In vivo, confocal microscopy (IVCM) identified Acanthamoeba cysts within the corneal stroma. Intensive amoebicidal therapy was initiated, but recovery was complicated by significant inflammation, resulting in widespread aggressive corneal vascularisation necessitating topical steroids and steroid-sparing agents. At 10 months, his left VA was 6/24. This report emphasises the importance of maintaining a high index of suspicion for AK in cases of post-CXL microbial keratitis and highlights the diagnostic value of IVCM, particularly in culture-negative and PCR-negative cases.

α-catenin mechanosensitivity as a route to cytokinesis failure through sequestration of LZTS2.

Epithelial cells can become polyploid upon tissue injury, but mechanosensitive cues that trigger this state are poorly understood. Using α-catenin (α-cat) knock-out Madin Darby Canine Kidney (MDCK) cells reconstituted with wild-type and mutant forms of α-cat as a model system, we find that an established α-cat actin-binding domain unfolding mutant designed to reduce force-sensitive binding to F-actin (α-cat-H0-FABD+) can promote cytokinesis failure, particularly along epithelial wound-fronts. Enhanced α-cat coupling to cortical actin is neither sufficient nor mitotic cell-autonomous for cytokinesis failure, but critically requires the mechanosensitive Middle-domain (M1-M2-M3) and neighboring cells. Disease relevant α-cat M-domain missense mutations known to cause a form of retinal pattern dystrophy (α-cat E307K or L436P) are associated with elevated binucleation rates via cytokinesis failure. Similar binucleation rates are seen in cells expressing an α-cat salt-bridge destabilizing mutant (R551A) designed to promote M2-M3 domain unfurling at lower force thresholds. Since binucleation is strongly enhanced by removal of the M1 as opposed to M2-M3 domains, cytokinetic fidelity is most sensitive to α-cat M2-M3 domain opening. To identify α-cat conformation-dependent proximity partners that contribute to cytokinesis, we used a biotin-ligase approach to distinguished proximity partners that show enhanced recruitment upon α-cat M-domain unfurling (R551A). We identified Leucine Zipper Tumor Suppressor 2 (LZTS2), an abscission factor previously implicated in cytokinesis. We confirm that LZTS2 enriches at the midbody, but discover it also localizes to tight and tricellular junctions. LZTS2 knock-down promotes binucleation in both MDCK and Retinal Pigmented Epithelial (RPE) cells. α-cat mutants with persistent M2-M3 domain opening showed elevated junctional enrichment of LZTS2 from the cytosol compared α-cat wild-type cells. These data implicate LZTS2 as a mechanosensitive effector of α-cat that is critical for cytokinetic fidelity. This model rationalizes how persistent mechano-activation of α-cat may drive tension-induced polyploidization of epithelia post-injury and suggests an underlying mechanism for how pathogenic α-cat mutations drive macular dystrophy.

PIGMENTATION IN FOCAL SCLERAL NODULE.

PURPOSE: To report a case of pigmentation in focal scleral nodule (FSN). METHODS: This is a single case report. RESULT: An asymptomatic 61-year-old woman was referred with small, partially pigmented raised lesion located at the superior margin of the optic nerve head. The lesion's clinical and multimodal imaging features were consistent for FSN including a dome-shaped elevation confined to the sclera with overlying choroidal thinning. However, the pigmentation within our lesion is a novel finding in FSN that has not been described before. CONCLUSION: To our knowledge, we report the first case of pigmentation in FSN. It is likely that our case was a typical FSN that then became pigmented, with melanosomes involving the flanges of the lesion where thin choroid remains. The understanding that FSN can be partially pigmented may eventually help unravel the origins of this poorly understood lesion.

Nasal turbinate mucosal graft for management of contracted anophthalmic socket.

A 67-year-old Caucasian male presented with severe contraction of socket lining 8 years after enucleation, dermis fat graft and successful ocular prosthesis fitting. Following two failed attempts at using amniotic membrane grafts to reform the socket lining, a total socket reconstruction was attempted using a novel nasal turbinate mucosal graft technique. This was performed in a staged fashion with lower fornix reconstruction followed by upper fornix reconstruction 3 months later. The patient was stable at 12 months review, with a satisfactory cosmetic outcome. Nasal turbinate mucosa was used as it was surgically accessible, provided natural socket lubrication due to its mucosal surface, and avoided oral mucosa and its associated morbidity. This case report suggests that nasal turbinate mucosa is a suitable autologous grafting material for total socket reconstruction in contracted anophthalmic sockets.

A proximity-dependent biotinylation map of a human cell.

Compartmentalization is a defining characteristic of eukaryotic cells, and partitions distinct biochemical processes into discrete subcellular locations. Microscopy1 and biochemical fractionation coupled with mass spectrometry2-4 have defined the proteomes of a variety of different organelles, but many intracellular compartments have remained refractory to such approaches. Proximity-dependent biotinylation techniques such as BioID provide an alternative approach to define the composition of cellular compartments in living cells5-7. Here we present a BioID-based map of a human cell on the basis of 192 subcellular markers, and define the intracellular locations of 4,145 unique proteins in HEK293 cells. Our localization predictions exceed the specificity of previous approaches, and enabled the discovery of proteins at the interface between the mitochondrial outer membrane and the endoplasmic reticulum that are crucial for mitochondrial homeostasis. On the basis of this dataset, we created humancellmap.org as a community resource that provides online tools for localization analysis of user BioID data, and demonstrate how this resource can be used to understand BioID results better.

Prognostic factors and epidemiology of adult open globe injuries from Western Sydney: a twelve-year review.

BACKGROUND: To identify prognostic factors determining final visual outcome following open globe injuries. METHODS: Retrospective case series of patients presenting to Westmead Hospital, Sydney, Australia with open globe injuries from 1st January 2005 to 31st December 2017. Data collected included demographic information, ocular injury details, management and initial and final visual acuities. RESULTS: A total of 104 cases were identified. Predictors of poor final visual outcomes included poor presenting visual acuity (p < 0.001), globe rupture (p < 0.001), retinal detachment (p < 0.001), Zone III wounds (p < 0.001), hyphema (p = 0.003), lens expulsion (p = 0.003) and vitreous hemorrhage (p < 0.001). Multivariate analysis demonstrated presenting visual acuity (p < 0.001), globe rupture (p = 0.013) and retinal detachment (p = 0.011) as being statistically significant for predicting poor visual outcomes. The presence of lid laceration (p = 0.197) and uveal prolapse (p = 0.667) were not significantly associated with the final visual acuity. CONCLUSIONS: Poor presenting visual acuity, globe rupture and retinal detachment are the most important prognostic factors determining final visual acuity following open globe injury.

Mitochondrial Threonyl-tRNA Synthetase TARS2 Is Required for Threonine-Sensitive mTORC1 Activation.

Mechanistic target of rapamycin complex 1 (mTORC1) controls cell growth and proliferation by sensing fluctuations in environmental cues such as nutrients, growth factors, and energy levels. The Rag GTPases (Rags) serve as a critical module that signals amino acid (AA) availability to modulate mTORC1 localization and activity. Recent studies have demonstrated how AAs regulate mTORC1 activity through Rags. Here, we uncover an unconventional pathway that activates mTORC1 in response to variations in threonine (Thr) levels via mitochondrial threonyl-tRNA synthetase TARS2. TARS2 interacts with inactive Rags, particularly GTP-RagC, leading to increased GTP loading of RagA. mTORC1 activity in cells lacking TARS2 is resistant to Thr repletion, showing that TARS2 is necessary for Thr-dependent mTORC1 activation. The requirement of TARS2, but not cytoplasmic threonyl-tRNA synthetase TARS, for this effect demonstrates an additional layer of complexity in the regulation of mTORC1 activity.

An Unusual Presentation of Pediatric Conjunctival Mucosa-Associated Lymphoid Tissue Lymphoma.

Ocular adnexal mucosa-associated lymphoid tissue (MALT) lymphoma is uncommon in the pediatric population. Initial misdiagnosis is common and there is lacking consensus regarding the optimal approach to treatment. Herein, we report an atypical presentation of pediatric conjunctival MALT lymphoma and review the presentation and management of this rare condition.

A conserved CCM complex promotes apoptosis non-autonomously by regulating zinc homeostasis.

Apoptotic death of cells damaged by genotoxic stress requires regulatory input from surrounding tissues. The C. elegans scaffold protein KRI-1, ortholog of mammalian KRIT1/CCM1, permits DNA damage-induced apoptosis of cells in the germline by an unknown cell non-autonomous mechanism. We reveal that KRI-1 exists in a complex with CCM-2 in the intestine to negatively regulate the ERK-5/MAPK pathway. This allows the KLF-3 transcription factor to facilitate expression of the SLC39 zinc transporter gene zipt-2.3, which functions to sequester zinc in the intestine. Ablation of KRI-1 results in reduced zinc sequestration in the intestine, inhibition of IR-induced MPK-1/ERK1 activation, and apoptosis in the germline. Zinc localization is also perturbed in the vasculature of krit1-/- zebrafish, and SLC39 zinc transporters are mis-expressed in Cerebral Cavernous Malformations (CCM) patient tissues. This study provides new insights into the regulation of apoptosis by cross-tissue communication, and suggests a link between zinc localization and CCM disease.

Plk4 Promotes Cancer Invasion and Metastasis through Arp2/3 Complex Regulation of the Actin Cytoskeleton.

The polo family serine threonine kinase Plk4 has been proposed as a therapeutic target in advanced cancers based on increased expression in primary human cancers, facilitation of tumor growth in murine xenograft models, and centrosomal amplification induced by its overexpression. However, both the causal link between these phenomena and the feasibility of selective Plk4 inhibition remain unclear. Here we characterize Plk4-dependent cancer cell migration and invasion as well as local invasion and metastasis of cancer xenografts. Plk4 depletion suppressed cancer invasion and induced an epithelial phenotype in poorly differentiated breast cancer cells. In an unbiased BioID screen for Plk4 interactors, we identified members of the Arp2/3 complex and confirmed a physical and functional interaction between Plk4 and Arp2 in mediating Plk4-driven cancer cell movement. This interaction is mediated through the Plk4 Polo-box 1-Polo-box 2 domain and results in phosphorylation of Arp2 at the T237/T238 activation site, which is required for Plk4-driven cell movement. Our results validate Plk4 as a therapeutic target in cancer patients and reveal a new role for Plk4 in regulating Arp2/3-mediated actin cytoskeletal rearrangement. Cancer Res; 77(2); 434-47. ©2016 AACR.

Perfluoroalkylphosphinic Acids in Northern Pike (Esox lucius), Double-Crested Cormorants (Phalacrocorax auritus), and Bottlenose Dolphins (Tursiops truncatus) in Relation to Other Perfluoroalkyl Acids.

Perfluoroalkyl phosphinic acids (PFPIAs) are perfluoroalkyl acids (PFAAs) that are used for their surfactant properties in a variety of applications, resulting in their presence in environmental waters; however, they have not been widely studied in biota. A survey of PFPIAs was conducted in fish, dolphins, and birds from various locations in North America. Northern pike (Esox lucius) were collected at two locations in 2011 near Montréal Island in the St. Lawrence River, Canada, double-crested cormorants (Phalacrocorax auritus) were collected from bird colonies in the Great Lakes in 2010-2012, and bottlenose dolphins (Tursiops truncatus) from Sarasota Bay, FL and Charleston Harbor, SC were sampled in 2004-2009. PFPIAs had a detection frequency of 100% in all animals. This is the first report of PFPIAs in fish, dolphin, and bird plasma. Total PFPIA levels (mean ± standard deviation, 1.87 ± 2.17 ng/g wet weight (ww), range of 0.112-15.3 ng/g ww) were 1-2 orders of magnitude lower than those of perfluoroalkyl carboxylates (PFCA) and perfluoroalkanesulfonates (PFSA) in the same samples. The predominant congeners were 6:8 PFPIA (cormorants and pike) and 6:6 PFPIA (dolphins). Total PFPIAs in cormorants from Hamilton Harbour (5.02 ± 2.80 ng/g ww) were statistically higher than in other areas and taxonomic groups. The ubiquity of PFPIAs warrants further research on sources and effects of these unique compounds.

Proximity biotinylation and affinity purification are complementary approaches for the interactome mapping of chromatin-associated protein complexes.

Mapping protein-protein interactions for chromatin-associated proteins remains challenging. Here we explore the use of BioID, a proximity biotinylation approach in which a mutated biotin ligase (BirA*) is fused to a bait of interest, allowing for the local activation of biotin and subsequent biotinylation of proteins in the bait vicinity. BioID allowed for successful interactome mapping of core histones and members of the mediator complex. We explored the background signal produced by the BioID approach and found that using distinct types of controls increased the stringency of our statistical analysis with SAINTexpress. A direct comparison of BioID with our AP-MS protocol optimized for chromatin-associated protein complexes revealed that the approaches identified few shared interaction partners and enriched for distinct biological processes; yet, both approaches permitted the recovery of biologically meaningful interactions. While no clear bias could be observed for either technique toward protein complexes of particular functions, BioID allowed for the purification of proteins of lower cellular abundance. Finally, we were able to identify a strong association of MED4 with the centrosome by BioID and validated this finding by immunofluorescence. In summary, BioID complements AP-MS for the study of chromatin-associated protein complexes. BIOLOGICAL SIGNIFICANCE: This manuscript describes the application of BioID, a proximity biotinylation approach, to chromatin-associated proteins, namely core histones and members of the mediator complex. We observed that BioID was successful at identifying known interaction partners for the baits tested, but also allowed novel putative interaction partners to be identified. By performing a detailed comparison of BioID versus a standard method for interactome mapping (affinity purification coupled to mass spectrometry, AP-MS), we show that the approaches were complementary, allowing for purification of different interaction partners. These interaction partners were different in the biological processes they are associated with, but also in their abundance. BioID represents a significant technical development in the field of chromatin research by expanding the search space for interactome mapping beyond what is possible with AP-MS. This article is part of a Special Issue entitled: Protein dynamics in health and disease. Guest Editors: Pierre Thibault and Anne-Claude Gingras.

Cell surface profiling using high-throughput flow cytometry: a platform for biomarker discovery and analysis of cellular heterogeneity.

Cell surface proteins have a wide range of biological functions, and are often used as lineage-specific markers. Antibodies that recognize cell surface antigens are widely used as research tools, diagnostic markers, and even therapeutic agents. The ability to obtain broad cell surface protein profiles would thus be of great value in a wide range of fields. There are however currently few available methods for high-throughput analysis of large numbers of cell surface proteins. We describe here a high-throughput flow cytometry (HT-FC) platform for rapid analysis of 363 cell surface antigens. Here we demonstrate that HT-FC provides reproducible results, and use the platform to identify cell surface antigens that are influenced by common cell preparation methods. We show that multiple populations within complex samples such as primary tumors can be simultaneously analyzed by co-staining of cells with lineage-specific antibodies, allowing unprecedented depth of analysis of heterogeneous cell populations. Furthermore, standard informatics methods can be used to visualize, cluster and downsample HT-FC data to reveal novel signatures and biomarkers. We show that the cell surface profile provides sufficient molecular information to classify samples from different cancers and tissue types into biologically relevant clusters using unsupervised hierarchical clustering. Finally, we describe the identification of a candidate lineage marker and its subsequent validation. In summary, HT-FC combines the advantages of a high-throughput screen with a detection method that is sensitive, quantitative, highly reproducible, and allows in-depth analysis of heterogeneous samples. The use of commercially available antibodies means that high quality reagents are immediately available for follow-up studies. HT-FC has a wide range of applications, including biomarker discovery, molecular classification of cancers, or identification of novel lineage specific or stem cell markers.

Neural correlates of behavioural symptoms in behavioural variant frontotemporal dementia and Alzheimers disease: employment of a visual MRI rating scale / Correlatos neuronais de sintomas de comportamento em demência frontotemporal e demência de Alzheimer: aplicação de uma escala visual clínica em ressonância magnética

Frontotemporal dementia (FTD) patients often present with severe behavioural disturbances and concomitant lack of insight. The underlying neural correlates of these disturbances are mostly attributed to prefrontal cortex dysfunction,but are still poorly understood. Objectives: The current study explores whether a simple visual magnetic resonance imaging(MRI) rating scale in combination with the Frontal System Behaviour Scale (FrSBe) can be used to identify the prefrontal correlates of behavioural symptoms in behavioural variant frontotemporal dementia (bvFTD) and Alzheimers disease (AD).Methods: Forty-eight patients with a clinical diagnosis of bvFTD and AD participated in the study. Their behavioural profiles were assessed using the Frontal System Behaviour Scale (FrSBe) and cross-correlated to the atrophy of the sub-regions inthe prefrontal cortex using a 5-point visual rating scale of MRI scans. Results: Patients with bvFTD showed higher incidenceof behavioural disturbances than AD with apathy being the most significant. BvFTD patients also showed the highestincidence of atrophy in the orbital frontal cortex and this atrophy was correlated with the apathetic features. Conclusions: Employment of a simple visual MRI rating scale can be used in combination with a behavioural screening test to identifyreliably the behavioural symptoms in bvFTD and AD. These findings will inform the diagnostic accuracy of the neural correlates of behavioural dysfunction in bvFTD in the future.

Pacientes com demência frontotemporal (DFT) frequentemente se apresentam com graves distúrbios comportamentais e concomitante falta de insight. Os correlatos neurais subjacentes a estes distúrbios são em sua maioria atribuídos a disfunção do córtex pré-frontal, porém, ainda são pouco compreendidos. Objetivos: O presente estudo explorase uma escala de mensuração visual de ressonância magnética (RM) em combinação com a Escala Comportamental doSistema Frontal podem ser usadas para identificar os correlatos pré-frontais de sintomas comportamentais na variantecomportamental da DFT (cDFT) e na doença de Alzheimer (DA). Métodos: Quarenta e oito pacientes com diagnóstico clínicode cDFT e DA participaram do estudo. Seus perfis comportamentais foram avaliados usando a Escala Comportamentaldo Sistema Frontal (ECSF) e correlacionada a atrofia das sub-regiões no córtex pré-frontal utilizando uma escala demensuração visual de 5 pontos na RM. Resultados: Os pacientes com cDFT mostraram uma maior incidência de distúrbioscomportamentais do que os com DA, sendo a apatia o sintoma mais significativo. Os pacientes com cDFT tambémdemonstraram uma maior incidência de atrofia no córtex orbito-frontal e esta atrofia correlacionou-se às característicasapáticas. Conclusões: O emprego de uma escala simples de mensuração visual de RM pode ser usada em combinação a um teste de rastreio comportamental para identificar de forma confiável os sintomas comportamentais na cDFT e DA. Estes achados informarão a acurácia diagnóstica dos correlatos neurais da disfunção comportamental na cDFT no futuro.

Neural correlates of behavioural symptoms in behavioural variant frontotemporal dementia and Alzheimer's disease: Employment of a visual MRI rating scale.

Frontotemporal dementia (FTD) patients often present with severe behavioural disturbances and concomitant lack of insight. The underlying neural correlates of these disturbances are mostly attributed to prefrontal cortex dysfunction, but are still poorly understood. OBJECTIVES: The current study explores whether a simple visual magnetic resonance imaging (MRI) rating scale in combination with the Frontal System Behaviour Scale (FrSBe) can be used to identify the prefrontal correlates of behavioural symptoms in behavioural variant frontotemporal dementia (bvFTD) and Alzheimer's disease (AD). METHODS: Forty-eight patients with a clinical diagnosis of bvFTD and AD participated in the study. Their behavioural profiles were assessed using the Frontal System Behaviour Scale (FrSBe) and cross-correlated to the atrophy of the sub-regions in the prefrontal cortex using a 5-point visual rating scale of MRI scans. RESULTS: Patients with bvFTD showed higher incidence of behavioural disturbances than AD with apathy being the most significant. BvFTD patients also showed the highest incidence of atrophy in the orbital frontal cortex and this atrophy was correlated with the apathetic features. CONCLUSIONS: Employment of a simple visual MRI rating scale can be used in combination with a behavioural screening test to identify reliably the behavioural symptoms in bvFTD and AD. These findings will inform the diagnostic accuracy of the neural correlates of behavioural dysfunction in bvFTD in the future.

Pacientes com demência frontotemporal (DFT) frequentemente se apresentam com graves distúrbios comportamentais e concomitante falta de insight. Os correlatos neurais subjacentes a estes distúrbios são em sua maioria atribuídos a disfunção do córtex pré-frontal, porém, ainda são pouco compreendidos. OBJETIVOS: O presente estudo explora se uma escala de mensuração visual de ressonância magnética (RM) em combinação com a Escala Comportamental do Sistema Frontal podem ser usadas para identificar os correlatos pré-frontais de sintomas comportamentais na variante comportamental da DFT (cDFT) e na doença de Alzheimer (DA). MÉTODOS: Quarenta e oito pacientes com diagnóstico clínico de cDFT e DA participaram do estudo. Seus perfis comportamentais foram avaliados usando a Escala Comportamental do Sistema Frontal (ECSF) e correlacionada a atrofia das sub-regiões no córtex pré-frontal utilizando uma escala de mensuração visual de 5 pontos na RM. RESULTADOS: Os pacientes com cDFT mostraram uma maior incidência de distúrbios comportamentais do que os com DA, sendo a apatia o sintoma mais significativo. Os pacientes com cDFT também demonstraram uma maior incidência de atrofia no córtex orbito-frontal e esta atrofia correlacionou-se às características apáticas. CONCLUSÕES: O emprego de uma escala simples de mensuração visual de RM pode ser usada em combinação a um teste de rastreio comportamental para identificar de forma confiável os sintomas comportamentais na cDFT e DA. Estes achados informarão a acurácia diagnóstica dos correlatos neurais da disfunção comportamental na cDFT no futuro.