Investigating Angiogenesis on a Functional and Molecular Level by Leveraging the Scratch Wound Migration Assay and the Spheroid Sprouting Assay.

Angiogenesis plays a crucial role in both physiological and pathological processes within the body including tumor growth or neovascular eye disease. A detailed understanding of the underlying molecular mechanisms and reliable screening models are essential for targeting diseases effectively and developing new therapeutic options. Several in vitro assays have been developed to model angiogenesis, capitalizing on the opportunities a controlled environment provides to elucidate angiogenic drivers at a molecular level and screen for therapeutic targets. This study presents workflows for investigating angiogenesis in vitro using human umbilical vein endothelial cells (HUVECs). We detail a scratch wound migration assay utilizing a live cell imaging system measuring endothelial cell migration in a 2D setting and the spheroid sprouting assay assessing endothelial cell sprouting in a 3D setting provided by a collagen matrix. Additionally, we outline strategies for sample preparation to enable further molecular analyses such as transcriptomics, particularly in the 3D setting, including RNA extraction as well as immunocytochemistry. Altogether, this framework offers scientists a reliable and versatile toolset to pursue their scientific inquiries in in vitro angiogenesis assays.

Hyalocytes-guardians of the vitreoretinal interface.

Originally discovered in the nineteenth century, hyalocytes are the resident macrophage cell population in the vitreous body. Despite this, a comprehensive understanding of their precise function and immunological significance has only recently emerged. In this article, we summarize recent in-depth investigations deciphering the critical role of hyalocytes in various aspects of vitreous physiology, such as the molecular biology and functions of hyalocytes during development, adult homeostasis, and disease. Hyalocytes are involved in fetal vitreous development, hyaloid vasculature regression, surveillance and metabolism of the vitreoretinal interface, synthesis and breakdown of vitreous components, and maintenance of vitreous transparency. While sharing certain resemblances with other myeloid cell populations such as retinal microglia, hyalocytes possess a distinct molecular signature and exhibit a gene expression profile tailored to the specific needs of their host tissue. In addition to inflammatory eye diseases such as uveitis, hyalocytes play important roles in conditions characterized by anomalous posterior vitreous detachment (PVD) and vitreoschisis. These can be hypercellular tractional vitreo-retinopathies, such as macular pucker, proliferative vitreo-retinopathy (PVR), and proliferative diabetic vitreo-retinopathy (PDVR), as well as paucicellular disorders such as vitreo-macular traction syndrome and macular holes. Notably, hyalocytes assume a significant role in the early pathophysiology of these disorders by promoting cell migration and proliferation, as well as subsequent membrane contraction, and vitreoretinal traction. Thus, early intervention targeting hyalocytes could potentially mitigate disease progression and prevent the development of proliferative vitreoretinal disorders altogether, by eliminating the involvement of vitreous and hyalocytes.

Central serous chorioretinopathy: An evidence-based treatment guideline.

Central serous chorioretinopathy (CSC) is a relatively common disease that causes vision loss due to macular subretinal fluid leakage and it is often associated with reduced vision-related quality of life. In CSC, the leakage of subretinal fluid through defects in the retinal pigment epithelial layer's outer blood-retina barrier appears to occur secondary to choroidal abnormalities and dysfunction. The treatment of CSC is currently the subject of controversy, although recent data obtained from several large randomized controlled trials provide a wealth of new information that can be used to establish a treatment algorithm. Here, we provide a comprehensive overview of our current understanding regarding the pathogenesis of CSC, current therapeutic strategies, and an evidence-based treatment guideline for CSC. In acute CSC, treatment can often be deferred for up to 3-4 months after diagnosis; however, early treatment with either half-dose or half-fluence photodynamic therapy (PDT) with the photosensitive dye verteporfin may be beneficial in selected cases. In chronic CSC, half-dose or half-fluence PDT, which targets the abnormal choroid, should be considered the preferred treatment. If PDT is unavailable, chronic CSC with focal, non-central leakage on angiography may be treated using conventional laser photocoagulation. CSC with concurrent macular neovascularization should be treated with half-dose/half-fluence PDT and/or intravitreal injections of an anti-vascular endothelial growth factor compound. Given the current shortage of verteporfin and the paucity of evidence supporting the efficacy of other treatment options, future studies-ideally, well-designed randomized controlled trials-are needed in order to evaluate new treatment options for CSC.

Clinical Landscape of Central Serous Chorioretinopathy in Germany: Retina.net CSC Registry Report Number 1.

INTRODUCTION: The German Registry of central serous chorioretinopathy (CSC) collects data on CSC patients in a nationwide multicenter approach to analyze epidemiology, risk factors, clinical presentations, as well as diagnosis and treatment patterns. METHODS: In this multicenter cohort study, patients with CSC were enrolled in nine tertiary referral centers in Germany between January 2022 and June 2023. After consenting to the study, demographic data, risk factors, reported symptoms, best-corrected visual acuity (BCVA), funduscopic findings, disease severity, and diagnostic and treatment decisions were recorded and analyzed. RESULTS: A total of 539 eyes of 411 CSC patients were enrolled in this study including 308 males (75%) and 103 females (25%). Patients were predominantly of Caucasian origin and had a mean age of 55.5 years (IQR 41.0-70.0). 28% of eyes were classified as acute (<4 months duration) CSC, 28% as chronic (>4 months duration) CSC, 21% as inactive CSC, 11% as chronic atrophic CSC, and 12% as CSC with secondary CNV. 128 patients (31%) demonstrated bilateral CSC. The most common risk factors reported were psychological stress (52%), smoking (38%), arterial hypertension (38%), and a history of or current use of steroids (30%). Most frequently encountered symptoms included decreased visual acuity (76%), metamorphopsia (49%), relative scotoma (47%), blurred vision (19%), and dyschromatopsia (9%). The mean logMAR BCVA on initial examination was 0.2 (≈20/30, IQR 0.2-0.4) but showed significant variation with a tendency of lower BCVA in chronic cases. At the baseline visit, 74% of the overall cohort received no treatment, while 19% underwent local treatment and only 2% underwent systemic treatment. Of the local therapies, anti-VEGF injections were the most frequently performed procedure (33%, mainly for secondary CNV), followed by micropulse laser (28%), focal nonpulsed laser (23%), verteporfin photodynamic therapy (14%), and nonsteroidal anti-inflammatory eye drops (2%). Among intravitreal anti-VEGF agents, aflibercept was used most frequently, followed by bevacizumab and ranibizumab. CONCLUSION: This registry represents one of the largest cohorts of European patients with CSC to date. Patient age and the proportion of women were higher than expected and bilateral active disease was lower than anticipated, highlighting that neither age nor gender should be overemphasized when diagnosing CSC. Therapeutic interventions are heterogeneous and include verteporfin photodynamic therapy, micropulse laser, and anti-VEGF injections in case of secondary CNV.

Retinal vessel volume reference database derived from volume-rendered optical coherence tomography angiography.

Optical coherence tomography angiography (OCTA) enables three-dimensional reconstruction of the functional blood vessels in the retina. Therefore, it enables the quantification of 3D retinal vessel parameters such as surface area and vessel volume. In spite of the widespread use of OCTA, no representative volume-rendered vessel volume (VV) data are published to date. In this study, OCTA 3 × 3 mm macular cubes were processed with volume-rendering techniques to measure VV in 203 eyes from 107 healthy volunteers. Generalized linear models (GLM) were constructed to assess the impact of age, gender, visual acuity (VA), spherical equivalent (SE), and axial length (AL) on VV. Overall mean VV was 0.23 ± 0.05mm3. Age and axial length showed a negative correlation with VV. However, GLM model analysis found that AL exerted the most pronounced influence on VV. No statistically significant associations were identified between gender or between left and right eyes. This is the first study to assess 3D OCTA VV and its naturally occurring variations in a large series of healthy subjects. It offers novel insights into the characterization of normal retinal vascular anatomy in healthy individuals, contributing to a valuable reference for future research in this field.

ZEISS PLEX Elite 9000 Widefield Optical Coherence Tomography Angiography as Screening Method for Early Detection of Retinal Hemangioblastomas in von Hippel-Lindau Disease.

Purpose: To evaluate early detection of retinal hemangioblastomas (RHs) in von Hippel-Lindau disease (VHLD) with widefield optical coherence tomography angiography (wOCTA) compared to the standard of care in ophthalmologic VHLD screening in a routine clinical setting. Methods: We conducted prospective comparisons of three screening methods: wOCTA, standard ophthalmoscopy, and fluorescein angiography (FA), which was performed only in uncertain cases. The numbers of detected RHs were compared among the three screening methods. The underlying causes for the lack of detection were investigated. Results: In 91 eyes (48 patients), 67 RHs were observed (mean, 0.74 ± 1.59 RH per eye). FA was performed in eight eyes. Ophthalmoscopy overlooked 25 of the 35 RHs detected by wOCTA (71.4%) due to the background color of the choroid (n = 5), small tumor size (n = 13), masking by a bright fundus reflex (n = 2), and masking by surrounding retinal scars (n = 5). However, wOCTA missed 29 RHs due to peripheral location (43.3%). The overall detection rates were up to 37% on the basis of ophthalmoscopy alone, up to 52% for wOCTA, and 89% for FA. Within the retinal area covered by wOCTA, the detection rates were up to 46.7% for ophthalmoscopy alone, up to 92.1% for wOCTA, and 73.3% for FA. Conclusions: The overall low detection rate of RHs using wOCTA is almost exclusively caused by its inability to visualize the entire peripheral retina. Therefore, in unclear cases, FA is necessary after ophthalmoscopy. Translational Relevance: Within the imageable retinal area, wOCTA shows a high detection rate of RHs and therefore may be suitable to improve screening for RHs in VHLD.

Psychometric assessment of patients with central serous chorioretinopathy and correlation with disease stage and progression: a case control study.

BACKGROUND: Central serous chorioretinopathy (CSC) has frequently been associated with increased stress levels as well as an increased prevalence of other psychiatric conditions. This study used standardized psychometric scores to assess stress, depression and anxiety levels of CSC patients and compared them to controls without retinal disease ("healthy") and with branch retinal vein occlusion (BRVO). METHODS: Monocentric, longitudinal case control study on consecutive CSC patients seen at a tertiary referral center. Controls without retinal disease were recruited from the oculoplastics clinic and those with BRVO from the medical retina clinic. Patients completed pseudonymized tests measuring stress levels (PHQ-stress), depression (PHQ-9) and anxiety (GAD-7) at baseline and at 3- and 6-months follow-up. Higher scores indicated higher trait levels. RESULTS: 65 CSC patients, 19 healthy controls and 19 BRVO patients were included in this study. CSC patients showed significantly higher stress levels at baseline compared to controls (p = 0.009), but not compared to BRVO patients (p = 1.00). At 3- and 6-months follow-up, no significant difference between groups was observed anymore. Acute CSC patients showed higher scores than those with chronic CSC, which also subsided over time. Depression and anxiety scores did not differ between groups at any timepoint. CONCLUSIONS: Patients with CSC do not show higher initial stress levels than patients with BRVO, while anxiety and depression levels did not differ from controls. Stress may thus rather represent a consequence of the onset of visual deterioration observed in CSC or other ocular diseases.

METHYLATION-ASSOCIATED PATHWAYS IN MACULAR TELANGIECTASIA TYPE 2 AND OPHTHALMOLOGIC FINDINGS IN PATIENTS WITH GENETIC METHYLATION DISORDERS.

PURPOSE: Serine (Ser) and glycine (Gly) levels were reported to differ between patients with macular telangiectasia type 2 (MacTel) compared with healthy controls. Because they are closely related to methylation metabolism, this report investigates methylation-associated metabolite levels in patients with MacTel and retinal changes in monogenetic methylation disorders. METHODS: Prospective, monocentric study on patients with MacTel and healthy controls underwent a standardized protocol including a blood draw. Methylation-associated metabolite levels in plasma were determined using targeted quantitative metabolomics. Furthermore, patient records of cystathionine beta-synthase, methylenetetrahydrofolate reductase, and methylmalonic aciduria and homocystinuria type C protein (MMACHC) deficiency were screened for reported retinal changes. RESULTS: In total, 29 patients with MacTel and 27 healthy controls were included. Patients with MacTel showed lower plasma Ser ( P = 0.02 and P = 0.01) and Gly ( P = 0.11 and P = 0.11) levels than controls. Principal component analyses revealed that methylation-associated metabolite, especially homocysteine, contributed to a distinct clustering of patients with MacTel. No retinal changes were seen in cystathionine beta-synthase (n = 1) and methylenetetrahydrofolate reductase (n = 2) deficiency, while two patients with MMACHC (n = 4) deficiency displayed extensive macular dystrophy. CONCLUSION: Patients with MacTel show distinct clustering of methylation-associated metabolite compared with controls. Of the three homocystinurias, only MMACHC resulted in macular dystrophy, possibly due to distinct compensatory pathways.

2D and 3D in vitro angiogenesis assays highlight different aspects of angiogenesis.

In angiogenesis research, scientists need to carefully select appropriate in vitro models to test their hypotheses to minimize the risk for false negative or false positive study results. In this study, we investigate molecular differences between simple two-dimensional and more complex three-dimensional angiogenesis assays and compare them to in vivo data from cancer-associated angiogenesis using an unbiased transcriptomic analysis. Human umbilical vein endothelial cells were treated with VEGF in 2D wound healing and proliferation assays and the 3D spheroid sprouting assay. VEGF-induced transcriptomic shifts were assessed in both settings by bulk RNA sequencing. Immunocytochemistry was used for protein detection. The data was linked to the transcriptomic profile of vascular endothelial cells from a single cell RNA sequencing dataset of various cancer tissue compared to adjacent healthy tissue control. VEGF induced a more diverse transcriptomic shift in vascular endothelial cells in a 3D experimental setting (767 differentially expressed genes) compared to the 2D settings (167 differentially expressed genes). Particularly, VEGF-induced changes in cell-matrix interaction, tip cell formation, and glycolysis were pronounced in the 3D spheroid sprouting experiments. Immunocytochemistry for VCAM1 and CD34 confirmed enhanced expression in response to VEGF-treatment in 3D settings. In vivo, vascular endothelial cells within various cancer tissue were characterized by strong transcriptomic changes in cell-matrix interaction and glycolysis similar to the 3D setting. Consequently, 3D assays may better address certain key aspects of angiogenesis in comparison to fast and scalable 2D assays. This should be taken into consideration within the context of each research question.

Transcriptional Comparison of Human and Murine Retinal Neovascularization.

Purpose: Retinal neovascularization (RNV) is the leading cause of vision loss in diseases like proliferative diabetic retinopathy (PDR). A significant failure rate of current treatments indicates the need for novel treatment targets. Animal models are crucial in this process, but current diabetic retinopathy models do not develop RNV. Although the nondiabetic oxygen-induced retinopathy (OIR) mouse model is used to study RNV development, it is largely unknown how closely it resembles human PDR. Methods: We therefore performed RNA sequencing on murine (C57BL/6J) OIR retinas (n = 14) and human PDR RNV membranes (n = 7) extracted during vitrectomy, each with reference to control tissue (n=13/10). Differentially expressed genes (DEG) and associated biological processes were analyzed and compared between human and murine RNV to assess molecular overlap and identify phylogenetically conserved factors. Results: In total, 213 murine- and 1223 human-specific factors were upregulated with a small overlap of 94 DEG (7% of human DEG), although similar biological processes such as angiogenesis, regulation of immune response, and extracellular matrix organization were activated in both species. Phylogenetically conserved mediators included ANGPT2, S100A8, MCAM, EDNRA, and CCR7. Conclusions: Even though few individual genes were upregulated simultaneously in both species, similar biological processes appeared to be activated. These findings demonstrate the potential and limitations of the OIR model to study human PDR and identify phylogenetically conserved potential treatment targets for PDR.

Face-down positioning or posturing after macular hole surgery.

BACKGROUND: Macular holes cause severe impairment of sight. With the aim of improving the outcome of surgery for macular holes, particularly larger macular holes (those measuring over 400 µm), a variable period of face-down positioning may be advised. This review is an update of a Cochrane Review published in 2011. OBJECTIVES: To evaluate the effect of postoperative face-down positioning on the outcome of surgery for macular hole. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2022, Issue 5), which contains the Cochrane Eyes and Vision Trials Register, Ovid MEDLINE, Ovid Embase, the ISRCTN registry, ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform. There were no date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 25 May 2022. SELECTION CRITERIA: We included randomised controlled trials (RCTs) in which postoperative face-down positioning was compared to no face-down positioning following surgery for macular holes. The primary outcome of interest was closure of the macular hole. Other outcomes of interest included visual outcomes, quality of life outcomes, and the occurrence of adverse events. Pairs of review authors independently selected studies for inclusion, extracted data, assessed risk of bias, and evaluated the certainty of evidence using GRADE. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. We analysed dichotomous data as risk ratios (RRs), and continuous data as mean differences (MDs), with 95% confidence intervals (CI). The unit of analysis was eyes. MAIN RESULTS: We included eight studies allocating a total of 709 eyes (699 participants). There was heterogeneity in study design, including the control group treatment (from no positioning to strict maintenance of other 'face-forward' postures) and surgical procedures (with or without inner limiting membrane peeling, with or without cataract surgery). There were also different durations of positioning, with two studies using 3 days, two studies using 5 days, and three studies using 10 days of face-down positioning. Whilst the overall risk of bias was low, all included studies were judged to be at high or unclear risk of bias due to absence of assessment of adherence to the 'prescribed' intervention of face-down positioning or posturing. The primary outcome of successful anatomical hole closure at one to six months following surgery was reported in 95 of every 100 eyes of participants advised to position face-down for at least three days after surgery, and in 85 of every 100 eyes of participants not advised to position face-down (RR 1.05, 95% CI 0.99 to 1.12, 709 eyes, 8 studies, I² = 44%). Amongst the 327 eyes of participants with macular holes of at least 400 µm, hole closure was noted in 94 of every 100 eyes of participants advised to position face-down, and in 84 of every 100 eyes of participants not advised to position face-down (RR 1.08, 95% CI 0.93 to 1.26, 5 studies, I² = 62%). Amongst the 129 eyes of participants with macular holes of less than 400 µm, hole closure was noted in 100 of every 100 eyes of participants advised to position face-down, and in 96 of every 100 eyes of participants not advised to position face-down (RR 1.03, CI 0.97 to 1.11, 4 studies, I² = 0%). The certainty of the evidence was low, downgraded for imprecision (CIs including no effect) and study design limitations (with different durations of face-down posturing used in the absence of a dose-response gradient, and limitations in measuring the exposure). Meta-analysis of visual acuity data was challenging given the use of different definitions of postoperative visual outcome across studies. Three studies reported findings by gain in Early Treatment Diabetic Retinopathy Study (ETDRS) letters (MD 2.04, 95% CI -0.01 to 4.09, very low-certainty evidence). Meta-analyses of quality of life data were not possible because of inconsistency in outcome metrics across studies. One study reported no difference between groups in quality of life, as reported on a validated quality of life metric scale (the National Eye Institute Visual Function Questionnaire - 25 (NEI VFQ-25), between face-down positioning for five days and non-face-down positioning (median NEI VFQ-25 score was 89 (interquartile range (IQR) 76 to 94) in the face-down group versus 87 (IQR 73 to 93) in the non-face-down group (adjusted mean difference on a logistic scale 0.02, 95% CI -0.03 to 0.07, P = 0.41)). Two studies reported increased ease of positioning and less pain in non-face-down positioning groups on non-validated 0-to-10-point visual analogue scores. On an ease-of-positioning score running from 0 (very difficult) to 10 (very easy), there were consistent reports of the discomfort associated with face-down positioning: the median participant-reported ease-of-positioning score was 6 (IQR 4 to 8) in those undergoing 5 days of face-down positioning versus 9 (IQR 7 to 10) in the comparator group (P = 0.01). On a pain score with 0 being pain-free and 10 being in severe pain, mean pain score was 6.52 ± 2.48 in the face-down positioning group versus 2.53 ± 2.6 in the non-face-down positioning group. The adverse event of postoperative nerve compression occurred in less than 1 in every 100 (3 per 1000) participants advised to position face-down, and 0 in every 100 participants not advised to position face-down (699 participants, 8 studies, moderate-certainty evidence). AUTHORS' CONCLUSIONS: We identified eight RCTs evaluating face-down positioning following surgery for macular hole. The included studies were not all directly comparable due to differences in the surgical techniques used and the durations of postoperative positioning advised. Low-certainty evidence suggests that face-down positioning may have little or no effect on macular hole closure after surgery. Face-down positioning is a low-risk intervention, with serious adverse events affecting fewer than 1 in 300 people. We suggest that any future trials focus on patients with larger macular holes, with interventions and outcome measures used in previous trials (i.e. with inner limiting membrane peeling, positioning durations of three to five days, and validated quality of life metrics) to allow future meta-analyses to determine any effect with greater precision and confidence.

Skewed X-inactivation is associated with retinal dystrophy in female carriers of RPGR mutations.

Progressive degeneration of rod and cone photoreceptors frequently is caused by mutations in the X-chromosomal gene Retinitis Pigmentosa GTPase Regulator (RPGR). Males hemizygous for a RPGR mutation often are affected by Retinitis Pigmentosa (RP), whereas female mutation carriers only occasionally present with severe RP phenotypes. The underlying pathomechanism leading to RP in female carriers is not well understood. Here, we analyzed a three-generation family in which two of three female carriers of a nonsense RPGR mutation presented with RP. Among two cell lines derived from the same female family members, differences were detected in RPGR transcript expression, in localization of RPGR along cilia, as well as in primary cilium length. Significantly, these differences correlated with alterations in X-chromosomal inactivation patterns found in the patient-derived cell lines from females. In summary, our data suggest that skewed X-chromosomal inactivation is an important factor that determines the disease manifestation of RP among female carriers of pathogenic sequence alterations in the RPGR gene.

Transcriptional Profiling Identifies Prognostic Gene Signatures for Conjunctival Extranodal Marginal Zone Lymphoma.

This study characterizes the transcriptional profile and the cellular tumor microenvironment of conjunctival extranodal marginal zone lymphoma (EMZL) and identifies prognostically relevant biomarkers. Ten formalin-fixed and paraffin-embedded conjunctival EMZL and eight healthy conjunctival specimens were analyzed by Massive Analysis of cDNA Ends (MACE) RNA sequencing. The 3417 upregulated genes in conjunctival EMZL were involved in processes such as B cell proliferation and Rac protein signaling, whereas the 1188 downregulated genes contributed most significantly to oxidative phosphorylation and UV protection. The tumor microenvironment, as determined by deconvolution analysis, was mainly composed of multiple B cell subtypes which reflects the tumor's B cell lineage. However, several T cell types, including T helper 2 cells and regulatory T cells, as well as innate immune cell types, such as anti-inflammatory macrophages and plasmacytoid dendritic cells, were also strongly enriched in conjunctival EMZL. A 13-biomarker prognostic panel, including S100A8 and S100A9, classified ocular and extraocular tumor recurrence, exceeded prognostic accuracy of Ann Arbor and American Joint Committee on Cancer (AJCC) staging, and demonstrated prognostic value for patient survival in 21 different cancer types in a database of 12,332 tumor patients. These findings may lead to new options of targeted therapy and may improve prognostic prediction for conjunctival EMZL.

STAT3 signaling induced by the IL-6 family of cytokines modulates angiogenesis.

Aberrant angiogenesis is a hallmark of cardiovascular and retinal neovascular disease. The STAT3 signaling pathway represents a potential pharmacological target for these diseases due to its impact on angiogenesis. Surprisingly, some STAT3 activators, such as the IL-6 cytokine family member oncostatin M (OSM), enhance angiogenesis, whereas others, such as ciliary neurotropic factor (CNTF), reduce it. This study aimed to clarify these conflicting effects. In contrast to the anti-angiogenic cytokine CNTF, the pro-angiogenic cytokine OSM was able to activate intracellular signaling pathways beyond the STAT3 pathway, including the ERK and AKT pathways. These differences translated into transcriptomic and metabolic shifts. siRNA-mediated STAT3 knockdown experiments showed a decrease in VEGF-induced endothelial migration and sprouting, enhancing the pro-angiogenic drive of OSM and switching the CNTF response from anti-angiogenic to pro-angiogenic. These effects correlated with a transcriptomic shift representing enhanced STAT1 and ERK activity following STAT3 knockdown, including a compensatory prolonged phosphorylated STAT1 activity. In conclusion, the angiogenic effect of STAT3 appears to be determined by cytokine-induced STAT3 specificity and simultaneous activity of other intracellular signaling pathways, whereas the STAT3 pathway, predominantly recognized for its pro-angiogenic phenotypes, reveals novel anti-angiogenic potential.

Web-based gene expression analysis-paving the way to decode healthy and diseased ocular tissue.

BACKGROUND: Gene expression analysis using RNA sequencing has helped to improve the understanding of many diseases. Databases, such as the Gene Expression Omnibus database of the National Center for Biotechnology Information provide RNA sequencing raw data from various diseased tissue types but their analysis requires advanced bioinformatics skills. Therefore, specific ocular databases provide the transcriptional profiles of different ocular tissues and in addition enable intuitive web-based data analysis. OBJECTIVE: The aim of this narrative review is to provide an overview of ocular transcriptome databases and to compare them with the Human Eye Transcriptome Atlas newly established in Freiburg. METHODS: PubMed literature search. RESULTS: A total of nine ocular transcriptome databases focusing on different aspects were identified. The iSyTE and Express platforms specialize in gene expression during lens and retinal development in mice, whereas retina.tigem.it, Eye in a Disk, and Spectacle focus on selected ocular tissues such as the retina. Spectacle, UCSC Cell Browser and Single Cell Portal allow intuitive exploration of single cell RNA sequencing data derived from retinal, choroid, cornea, iris, trabecular meshwork and sclera specimens. The microarray profiles of a variety of healthy ocular tissues are included in the Ocular Tissue Database. The Human Eye Transcriptome Atlas provides the largest collection of different ocular tissue types, contains the highest number of ocular diseases and is characterized by a high level of quality achieved by methodological consistency. CONCLUSION: Ocular transcriptome databases provide comprehensive and intuitive insights into the transcriptional profiles of a variety of healthy and diseased ocular tissues. Thus, they improve our understanding of the underlying molecular mediators, support hypothesis generation and help in the search for new diagnostic and therapeutic targets for various ocular diseases.

Transcriptional profiling specifies the pathogen-specific human host response to infectious keratitis.

Purpose: Corneal infections are a leading cause of visual impairment and blindness worldwide. Here we applied high-resolution transcriptomic profiling to assess the general and pathogen-specific molecular and cellular mechanisms during human corneal infection. Methods: Clinical diagnoses of herpes simplex virus (HSV) (n=5) and bacterial/fungal (n=5) keratitis were confirmed by histology. Healthy corneas (n=7) and keratoconus (n=4) samples served as controls. Formalin-fixed, paraffin-embedded (FFPE) human corneal specimens were analyzed using the 3' RNA sequencing method Massive Analysis of cDNA Ends (MACE RNA-seq). The cellular host response was investigated using comprehensive bioinformatic deconvolution (xCell and CYBERSORTx) analyses and by integration with published single cell RNA-seq data of the human cornea. Results: Our analysis identified 216 and 561 genes, that were specifically overexpressed in viral or bacterial/fungal keratitis, respectively, and allowed to distinguish the two etiologies. The virus-specific host response was driven by adaptive immunity and associated molecular signaling pathways, whereas the bacterial/fungal-specific host response mainly involved innate immunity signaling pathways and cell types. We identified several genes and pathways involved in the host response to infectious keratitis, including CXCL9, CXCR3, and MMP9 for viral, and S100A8/A9, MMP9, and the IL17 pathway for bacterial/fungal keratitis. Conclusions: High-resolution molecular profiling provides new insights into the human corneal host response to viral and bacterial/fungal infection. Pathogen-specific molecular profiles may provide the foundation for novel diagnostic biomarker and therapeutic approaches that target inflammation-induced damage to corneal host cells with the goal to improve the outcome of infectious keratitis.

Transcriptional Profiling Provides New Insights into Organ Culture-Induced Changes in Human Donor Corneas.

Corneal transplantation is one of the most common forms of tissue transplantation worldwide. Donor corneal tissue used in transplantation is provided by eye banks, which store the tissue in culture medium after procurement. To date, the effects of cell culture on human corneal tissue have not been fully elucidated. Using the 3' RNA sequencing method for massive analysis of cDNA ends (MACE), we show that cultivation of corneal tissue leads to significant changes in a variety of molecular processes in human corneal tissue that go well beyond aspects of previously known culture effects. Functionally grouped network analysis revealed nine major groups of biological processes that were affected by corneal organ culture, among them keratinization, hypoxia, and angiogenesis, with genes from each group being affected by culture time. A cell type deconvolution analysis revealed significant modulations of the corneal immune cell profile in a time dependent manner. The results suggest that current culture conditions should be further refined and that prolonged cultivation may be detrimental. Recently, we showed that MACE enables transcriptional profiling of formalin-fixed and paraffin-embedded (FFPE) conjunctival tissue with high accuracy even after more than 10 years of storage. Here we demonstrate that MACE provides comparable results for native and FFPE corneal tissue, confirming that the technology is suitable for transcriptome analysis of a wide range of archived diseased corneal samples stored in histological archives. Finally, our data underscore the feasibility of bioinformatics cell-type enrichment analysis in bulk RNA-seq data to profile immune cell composition in fixed and archived corneal tissue samples, for which RNA-seq analysis of individual cells is often not possible.

Hyalocytes in proliferative vitreo-retinal diseases.

Introduction: Hyalocytes are sentinel macrophages residing within the posterior vitreous cortex anterior to the retinal inner limiting membrane (ILM). Following anomalous PVD and vitreoschisis, hyalocytes contribute to paucicellular (vitreo-macular traction syndrome, macular holes) and hypercellular (macular pucker, proliferative vitreo-retinopathy, proliferative diabetic vitreo-retinopathy) diseases. Areas covered: Studies of human tissues employing dark-field, phase, and electron microscopy; immunohistochemistry; and in vivo imaging of human hyalocytes. Expert opinion: Hyalocytes are important in early pathophysiology, stimulating cell migration and proliferation, as well as subsequent membrane contraction and vitreo-retinal traction. Targeting hyalocytes early could mitigate advanced disease. Ultimately, eliminating the role of vitreous and hyalocytes may prevent proliferative vitreo-retinal diseases entirely.

[Next-generation sequencing in ophthalmology]. / Next-Generation-Sequencing in der Augenheilkunde.

New methods for basic research are finding their way into ophthalmology and expand the options for research, diagnostics and treatment. This article centers on the study of gene activity in cells and tissues by next-generation sequencing (NGS). Following a brief introduction to the basic principles of NGS, this article focuses on transcriptome analysis by RNA sequencing using examples from ophthalmology. The RNA sequencing provides a comprehensive and unbiased overview of gene activity in cells and tissues and thus forms an important foundation for generating new testable scientific hypotheses. It thus contributes to the in-depth characterization of pathological changes and supports the development of new diagnostic and therapeutic approaches.