Anterior chamber proliferative membrane interception (AC-PMI)-enhanced trabeculectomy versus trabeculectomy for treating neovascular glaucoma: protocol for a randomized controlled trial.

BACKGROUND: Neovascular glaucoma (NVG) is an irreversible blinding eye disease worldwide and is classified as one of the refractory glaucoma conditions, severely impacting visual function and vision. Unfortunately, effective surgical interventions to improve the prognosis of NVG patients are currently lacking. The study aims to evaluate the efficacy and safety of anterior chamber proliferative membrane interception (AC-PMI)-enhanced trabeculectomy compared to the traditional trabeculectomy. METHODS: AC-PMI enhanced trabeculectomy versus trabeculectomy for the treatment of NVG is a single-center, prospective, double-arms, and randomized controlled trial of superior efficacy, which will involve 100 NVG inpatients. Patients will be randomly assigned into two groups using the random number table method. One group will undergo trabeculectomy using anti-vascular endothelial growth factor (Anti-VEGF) preoperatively and mitomycin C intraoperatively, while the other group will undergo AC-PMI enhanced trabeculectomy with the same medications (Anti-VEGF and mitomycin C). The patients will be followed up at the baseline and 1 day, 1 week, 1 month, 3 months, 6 months, 12 months, 18 months, and 24 months postoperatively. Meanwhile, we will collect the demographics, characteristics, and examination results and monitor any occurrences of adverse events at each follow-up time. DISCUSSION: This is an efficacy study of a novel surgical approach for treating neovascular glaucoma. Building upon conventional filtering surgeries, this approach introduces an additional step involving the interception of the proliferative membrane to effectively halt the growth of fibrovascular tissue. This study aims to explore a promising new surgical approach for managing NVG and contribute to the advancement of glaucoma treatment strategies. TRIAL REGISTRATION: ChiCTR ChiCTR2200055138. Registered on 01 January 2022. https://www.chictr.org.cn/showproj.html?proj=145255.

ISR inhibition reverses pancreatic ß-cell failure in Wolfram syndrome models.

Pancreatic ß-cell failure by WFS1 deficiency is manifested in individuals with wolfram syndrome (WS). The lack of a suitable human model in WS has impeded progress in the development of new treatments. Here, human pluripotent stem cell derived pancreatic islets (SC-islets) harboring WFS1 deficiency and mouse model of ß cell specific Wfs1 knockout were applied to model ß-cell failure in WS. We charted a high-resolution roadmap with single-cell RNA-seq (scRNA-seq) to investigate pathogenesis for WS ß-cell failure, revealing two distinct cellular fates along pseudotime trajectory: maturation and stress branches. WFS1 deficiency disrupted ß-cell fate trajectory toward maturation and directed it towards stress trajectory, ultimately leading to ß-cell failure. Notably, further investigation of the stress trajectory identified activated integrated stress response (ISR) as a crucial mechanism underlying WS ß-cell failure, characterized by aberrant eIF2 signaling in WFS1-deficient SC-islets, along with elevated expression of genes in regulating stress granule formation. Significantly, we demonstrated that ISRIB, an ISR inhibitor, efficiently reversed ß-cell failure in WFS1-deficient SC-islets. We further validated therapeutic efficacy in vivo with ß-cell specific Wfs1 knockout mice. Altogether, our study provides novel insights into WS pathogenesis and offers a strategy targeting ISR to treat WS diabetes.

Widefield swept-source optical coherence tomography angiography metrics associated with neovascular glaucoma in patients with proliferative diabetic retinopathy.

PURPOSE: To explore the association between widefield swept-source optical coherence tomography angiography (WF SS-OCTA) metrics, including nonperfusion area (NPA) and neovascularization (NV), and presence of neovascular glaucoma (NVG) in patients with proliferative diabetic retinopathy (PDR). METHODS: A prospective, cross-sectional study was conducted from November 2018 to February 2020. A total of 85 eyes of 60 PDR patients without NVG and 9 eyes of 8 PDR patients with NVG were included. Retinal ischemic parameters (NPA; ischemia index [NPA/total retinal area]) and NV features (NV number; NV area; NV vessel density) were evaluated. Foveal avascular zone (FAZ), macular thickness/volume, and choroidal thickness/volume were obtained using the Zeiss ARI Network. WF SS-OCTA retinal and choroidal metrics, systemic, and ocular parameters were screened using Least Absolute Shrinkage and Selection Operator (LASSO) logistic regression for variable selection. Firth's bias-reduced logistic regression (outcome: presence of NVG) was subsequently used to identify parameters associated with NVG. RESULTS: After LASSO variable selection, 8 variables were significantly associated with the presence of NVG: DM duration (years), insulin (yes/no), best-corrected visual acuity (BCVA) (logMAR), IOP, ischemia index, skeletonized vessel density, macular thickness (inner inferior, outer temporal regions). Firth's bias-reduced logistic regression showed ischemia index (odds ratio [OR]=13.2, 95% confidence interval [CI]:5.3-30.7, P<0.001) and BCVA (OR=5.8, 95%CI:1.2-28.8, P<0.05) were associated with the presence of NVG. NV metrics, FAZ, and choroidal parameters were not related to NVG. CONCLUSIONS: Retinal ischemia but not NV was associated with the presence of NVG in patients with PDR using WF SS-OCTA. Larger, longitudinal studies are needed to validate imaging biomarkers associated with diabetic NVG.

Quantitative Wide-Field Swept-Source Optical Coherence Tomography Angiography and Visual Outcomes in RAO.

Purpose: Retinal artery occlusion (RAO) is an ophthalmic emergency that can lead to poor visual outcomes and is associated with an increased risk of stroke and cardiovascular events. Wide-field swept-source OCT-A (WF SS-OCTA) can provide quick and non-invasive angiographic information with a wide field of view. Here, we looked for associations between OCT-A vascular imaging metrics and vision in RAO patients. Methods: Patients with diagnoses of central (CRAO) or branched retinal artery occlusion (BRAO) were included. 6mm × 6mm Angio and 15mm × 15mm AngioPlex Montage OCT-A images were obtained for both eyes in each patient using Zeiss Plex Elite 9000 WF SS-OCTA device. Each 6mm × 6mm image was divided into nine Early Treatment Diabetic Retinopathy Study (ETDRS) subfields. Non-perfusion area (NPA) was manually measured using 15mm × 15mm images. A linear regression model was utilized to identify correlation between imaging metrics and vision. P-values less than 0.05 were considered as statistically significant. Results: Twenty-five subjects were included. For RAO eyes, there was a statistically significant inverse correlation between retinal thickness as well as superficial capillary plexus (SCP) vessel density (VD) and vision. An inverse correlation was found between deep capillary plexus (DCP) VD and vision without statistical significance. There was a positive correlation between choroidal thickness as well as choroidal volume and vision without statistical significance. No significant correlation was found between the metrics and vision in contralateral eyes. For NPA and vision, no significant correlation was identified. Conclusion: This is the first study to investigate the utility of WF SS-OCTA in RAO and to demonstrate correlations between retinal vascular imaging metrics and visual outcomes. The results of this study provide a basis to understand the structural changes involved in vision in RAO and may guide management of RAO and prevention of cerebral stroke and cardiovascular accidents.

Structure-function associations between contrast sensitivity and widefield swept-source optical coherence tomography angiography in diabetic macular edema.

PURPOSE: To evaluate the relationship between contrast sensitivity (CS) and widefield swept-source optical coherence tomography angiography (WF SS-OCTA) vascular metrics in diabetic macular edema (DME) was the purpose. METHODS: This prospectively enrolled cross-sectional observational study included 61 eyes of 48 patients that were tested with the quantitative CS function (qCSF) test on the same day as imaging with WF SS-OCTA (PLEX® Elite 9000, Carl Zeiss Meditec) 3 × 3, 6 × 6, and 12 × 12 mm scans. Outcomes included visual acuity (VA) and multiple qCSF metrics. Vascular metrics included vessel density (VD) and vessel skeletonized density (VSD) in the superficial (SCP) and deep capillary plexus (DCP) and whole retina (WR) and foveal avascular zone (FAZ) parameters. Mixed effects multivariable linear regression models controlling for age, lens status, and diabetic retinopathy stage were performed. Standardized beta coefficients were calculated by refitting the standardized data. RESULTS: SS-OCTA metrics had a significant association with CS and VA. The effect size of OCTA metrics was larger on CS compared to VA. For example, the standardized beta coefficients for VSD and CS at 3 cpd (ßSCP = 0.76, ßDCP = 0.71, ßWR = 0.72, p < 0.001) were larger than those for VA (ßSCP = - 0.55, p < 0.001; ßDCP = - 0.43, p = 0.004; ßWR = - 0.50, p < 0.001). On 6 × 6 mm images, AULCSF, CS at 3 cpd, and CS at 6 cpd were significantly associated with VD and VSD in all three slab types (SCP, DCP, and WR), while VA was not. CONCLUSION: Structure-function associations in patients with DME leveraging the qCSF device suggest microvascular changes on WF SS-OCTA are associated with larger changes in contrast sensitivity than VA.

Remodeling of H3K9me3 during the pluripotent to totipotent-like state transition.

Multiple chromatin modifiers associated with H3K9me3 play important roles in the transition from embryonic stem cells to 2-cell (2C)-like cells. However, it remains elusive how H3K9me3 is remodeled and its association with totipotency. Here, we integrated transcriptome and H3K9me3 profiles to conduct a detailed comparison of 2C embryos and 2C-like cells. Globally, H3K9me3 is highly preserved and H3K9me3 dynamics within the gene locus is not associated with gene expression change during 2C-like transition. Promoter-deposited H3K9me3 plays non-repressive roles in the activation of genes during 2C-like transition. In contrast, transposable elements, residing in the nearby regions of up-regulated genes, undergo extensive elimination of H3K9me3 and are tended to be induced in 2C-like transitions. Furthermore, a large fraction of trophoblast stem cell-specific enhancers undergo loss of H3K9me3 exclusively in MERVL+/Zscan4+ cells. Our study therefore reveals the unique H3K9me3 profiles of 2C-like cells, facilitating the further exploration of totipotency.

Prevalence of venous loops and association with retinal ischemia in diabetic retinopathy using widefield swept-source OCT angiography.

PURPOSE: To investigate the prevalence and clinical characteristics of diabetic patients with retinal venous loops (RVLs) and to assess the association with retinal ischemia using widefield swept-source optical coherence tomography angiography (WF SS-OCTA). METHODS: In this retrospective, cross-sectional study, a total of 195 eyes of 132 diabetic patients (31 eyes with no diabetic retinopathy (DR), 76 eyes with nonproliferative DR (NPDR), and 88 eyes with proliferative DR (PDR)) were imaged with WF SS-OCTA using Angio 6 × 6 mm and Montage 15 × 15 mm scans. Quantitative ischemia-related parameters, including ischemia index (ratio of nonperfusion area to total retinal area), foveal avascular zone (FAZ), and neovascularization features, were evaluated. RVLs were classified as type I or type II according to the branching level of the feeder vessel. A multivariate generalized estimating equations (GEE) logistic regression model was used to analyze the association of systemic parameters and ischemia-related metrics with RVLs in PDR eyes. RESULTS: Forty-eight RVLs were identified in 22 eyes (11.28%). The prevalence of RVLs was higher in PDR compared to NPDR eyes (21.59% vs. 3.95%, P < 0.05). Type II RVLs accounted for a higher proportion than type I (89.58% vs. 10.42%, P < 0.001). RVLs were more likely to originate from superior (vs. inferior) and temporal (vs. nasal) veins (P < 0.05). The GEE model showed that neovascularization (NV) flow area and diastolic blood pressure were associated with RVLs in the PDR group (P < 0.05). CONCLUSION: WF SS-OCTA is useful for the identification of RVLs in patients with DR. NV flow area and diastolic blood pressure were associated with the presence of RVLs in eyes with PDR. Ischemia index, FAZ, and other WF SS-OCTA parameters were not associated with RVLs. Further longitudinal studies are needed to identify the role of RVLs in DR progression.

Characterising collateral vessels in eyes with branch retinal vein occlusions using widefield swept-source optical coherence tomography angiography.

BACKGROUND/AIMS: To characterise the morphology, location and functional significance of both macular and extramacular collateral vessels (CVs) in patients with a history of branch retinal vein occlusion (BRVO) using widefield swept-source optical coherence tomography angiography (WF SS OCTA). METHODS: Patients with a history of BRVO underwent WF SS OCTA testing to acquire 12×12 mm images, which were evaluated for CVs and non-perfusion area (NPA). Region of interest analysis of individual CVs was performed to identify correlations between CV size, depth and retinal location. Mixed effects multivariate regression analyses of factors associated with NPA and visual acuity (VA) were performed. RESULTS: Fifty-five CVs were identified in 28 BRVO eyes from 27 patients. CVs were identified in 42.9% (12/28) of eyes with a history of BRVO, and of these, 45.5% (25/55) were extramacular. The majority of CVs (87.3%, 48/55) coursed through both the superficial and the deep capillary plexus (DCP), while a subset (12.7%, 7/55) were strictly superficial. No CVs were found to course strictly through the DCP alone. CV depth increased with distance from the optic disc (p=0.011) and CV size increased with distance from the fovea (p=0.005). There were no statistically significant associations between CVs and NPA, or between CVs and VA. CONCLUSIONS: WF SS OCTA revealed that a large fraction of CVs that form after BRVO are extramacular, and the morphology of CVs varies as a function of retinal location. Depth-resolved study of CVs may offer valuable insights on the pathophysiological mechanisms leading to the development of macular oedema.

Clinical outcomes of penetrating canaloplasty in patients with traumatic angle recession glaucoma: a prospective interventional case series.

BACKGROUND/AIM: To evaluate the clinical outcomes of penetrating canaloplasty in traumatic angle recession glaucoma at 1 year. METHODS: Patients with angle recession glaucoma underwent penetrating canaloplasty, a new Schlemm's canal-based internal drainage procedure, which creates a direct canal for flow of aqueous humour from the anterior chamber to the ostia of Schlemm's canal via a window created at the corneal scleral bed without use of antimetabolites. Postoperative intraocular pressure (IOP), number of glaucoma medications, and procedure-related complications were evaluated. Success was defined as an IOP ≤21 mm Hg without (complete) or with (qualified) use of glaucoma medication. RESULTS: Forty eyes in 40 patients with angle recession glaucoma underwent successful circumferential catheterisation. The mean patient age was 42±13 years. In patients with penetrating canaloplasty that was deemed to be completely successful, the mean IOP decreased from a preoperative value of 37.8±12.3 mm Hg on 3.3±1.2 anti-glaucoma medications to 18.5±6.4 mm Hg on 1.2±1.4 medications, 14.9±4.6 mm Hg on 0.1±0.5 medications, 15.7±5.4 mm Hg on 0.1±0.4 medications and 14.8±3.6 mm Hg on 0.1±0.5 medications at 1, 3, 6 and 12 months postoperatively (p<0.05). Complete success was achieved in 35/40 eyes (87.5%) at 6 months and in 34/38 (89.5%) at 12 months. Hyphema (18/40, 45.0%) and transient IOP elevation (≥30 mm Hg, 9/40, 22.5%) were the most common postoperative complications. CONCLUSION: Penetrating canaloplasty significantly reduces IOP and has a high success rate in angle recession glaucoma. TRIAL REGISTRATION NUMBER: ChiCTR1900020511.

Wide-field swept-source optical coherence tomography angiography in the assessment of retinal microvasculature and choroidal thickness in patients with myopia.

BACKGROUND/AIMS: Pathological myopia (PM) is a leading cause of blindness worldwide. We aimed to evaluate microvascular and chorioretinal changes in different stages of myopia with wide-field (WF) swept-source (SS) optical coherence tomography angiography (OCTA). METHODS: This prospective cross-sectional observational study included 186 eyes of 122 patients who had undergone imaging between November 2018 and October 2020. Vessel density (VD) and vessel skeletonised density (VSD) of superficial capillary plexus, deep capillary plexus and whole retina, as well as foveal avascular zone parameters, retinal thickness (RT) and choroidal thickness (CT), were calculated. RESULTS: This study evaluated 75 eyes of 48 patients with high myopia (HM), 43 eyes of 31 patients with mild to moderate myopia and 68 eyes of 53 age-matched controls. Controlling for age and the presence of systemic hypertension, we found that HM was associated with decrease in VD and VSD in all layers on 12×12 mm² scans. Furthermore, HM was associated with a VD and VSD decrease in every Early Treatment Diabetic Retinopathy Study grid, with a larger decrease temporally (ßVD=-0.39, ßVSD=-10.25, p<0.01). HM was associated with decreased RT and CT. Reduction in RT was outside the macular region, while reduction in CT was in the macular region. CONCLUSION: Using WF SS-OCTA, we identified reduction in microvasculature and structural changes associated with myopia. Decrease in VD and VSD was greater in the temporal quadrant, and reductions in RT and CT were uneven across the retina. Further work may help identify risk factors for the progression of PM and associated vision-threatening complications.

Outcomes of Penetrating Canaloplasty in Childhood Glaucoma.

PRCIS: Penetrating canaloplasty was safe and effective for the management of refractory childhood glaucoma. PURPOSE: The purpose of this paper is to report the safety and efficacy of penetrating canaloplasty for the management of childhood glaucoma. MATERIALS AND METHODS: This single-center prospective interventional case series enrolled 50 eyes of 32 patients with childhood glaucoma between July 2017 and July 2020. Penetrating canaloplasty to create direct communication between the anterior chamber and tensioning suture-dilated the Schlemm canal was performed through a trabecular meshwork ostium in the affected eyes. Preoperative and postoperative intraocular pressure (IOP), number of glaucoma medications, and procedure-related complications were recorded. Qualified and complete success was defined as IOP≥5 and ≤21 mm Hg with or without glaucoma medications, respectively. RESULTS: A total of 43 eyes (86.0%) achieved 360 degrees catheterization of Schlemm canal and completed penetrating canaloplasty. The median age at surgery was 5 years (range, 10 d-17 y, mean 6.20±5.46 y). The mean IOP decreased from 33.11±10.89 mm Hg on 2 medications (median, range: 0-5) before surgery to 13.46±4.71 mm Hg on 0 medications (median, range:0-2) postoperatively at 12 months ( P <0.001). Complete and qualified success rates were 81.08% and 89.19%, respectively, at the 12-month follow-up. Hyphema (6/43, 13.95%) and a transient shallow anterior chamber with hypotony (5/43, 11.63%) were the most commonly observed early complications. CONCLUSION: Penetrating canaloplasty demonstrated good safety and efficacy in eyes with childhood glaucoma, and may be considered an option for managing refractory childhood glaucoma.

Achieving Inner Aqueous Drain in Glaucoma Secondary to Iridocorneal Endothelial Syndrome: One Year Results of Penetrating Canaloplasty.

PURPOSES: To report the efficacy of a bleb-independent penetrating canaloplasty in the management of glaucoma secondary to iridocorneal endothelial syndrome (GS-ICE). DESIGN: Prospective, non-comparative clinical study. METHODS: Penetrating canaloplasty was performed on 35 eyes from 35 patients with GS-ICE and medically uncontrolled intraocular pressure (IOP) between January 2018 and April 2020. Patients were followed up at 1 week, months 1, 3, 6, 12 postoperatively, and semi-annually thereafter. The IOP, anti-glaucoma medication, and surgery-related complications were recorded. Surgical success was defined as IOP ≥ 5 mmHg and ≤ 21 mmHg without (complete success) or with/without (qualified success) IOP-lowering medication. RESULTS: A total of 29 eyes (82.9%) had 360° catheterization and successfully received penetrating canaloplasty. Of these eyes, 24 (82.8%) achieved qualified success and 22 (75.9%) achieved qualified success at 12 months after surgery. The mean IOP decreased from 39.5 ± 11.8 mmHg on 2.9 ± 1.0 medications before surgery to 16.6 ± 5.3 mmHg (P < .001) on 0.2 ± 0.6 medications (P < .001) at 12 months postoperatively, respectively. Hyphema (37.9%), transient hypotony (34.5%), and transient postoperative IOP elevation (≥ 30 mmHg, 17.9%) were the most commonly observed early complications at the 1 week and 1 month visits. From 1 month and beyond, all treated eyes showed no obvious bleb at the operation quadrant. CONCLUSIONS: Penetrating canaloplasty rescued the inner aqueous outflow in ICE eyes and demonstrated acceptable success in IOP control with few complications, providing a new option for the management of GS-ICE.

Nonperfusion Area and Other Vascular Metrics by Wider Field Swept-Source OCT Angiography as Biomarkers of Diabetic Retinopathy Severity.

Purpose: To study the wider field swept-source optical coherence tomography angiography (WF SS-OCTA) metrics, especially non-perfusion area (NPA), in the diagnosing and staging of DR. Design: Cross-sectional observational study (November 2018-September 2020). Participants: 473 eyes of 286 patients (69 eyes of 49 control patients and 404 eyes of 237 diabetic patients). Methods: We imaged using 6mm×6mm and 12mm×12mm angiograms on WF SS-OCTA. Images were analyzed using the ARI Network and FIJI ImageJ. Mixed effects multiple regression models and receiver operator characteristic analysis was used for statistical analyses. Main Outcome Measures: Quantitative metrics such as vessel density (VD); vessel skeletonized density (VSD); foveal avascular zone (FAZ) area, circularity, and perimeter; and NPA in DR and their relative performance for its diagnosis and grading. Results: Among patients with diabetes (median age 59 years), 51 eyes had no DR, 185 eyes (88 mild, 97 moderate-severe) had non-proliferative DR (NPDR); and 168 eyes had proliferative DR (PDR). Trend analysis revealed a progressive decline in superficial capillary plexus (SCP) VD and VSD, and increased NPA with increasing DR severity. Additionally, there was a significant reduction in deep capillary plexus (DCP) VD and VSD in early DR (mild NPDR), but the progressive reduction in advanced DR stages was not significant. NPA was the best parameter to diagnose DR (AUC:0.96), whereas all parameters combined on both angiograms efficiently diagnosed (AUC:0.97) and differentiated between DR stages (AUC range:0.83-0.97). The presence of diabetic macular edema was associated with reduced SCP and DCP VD and VSD within mild NPDR eyes, whereas an increased VD and VSD in SCP among moderate-severe NPDR group. Conclusions: Our work highlights the importance of NPA, which can be more readily and easily measured with WF SS-OCTA compared to fluorescein angiography. It is additionally quick and non-invasive, and hence can be an important adjunct for DR diagnosis and management. In our study, a combination of all OCTA metrics on both 6mm×6mm and 12mm×12mm angiograms had the best diagnostic accuracy for DR and its severity. Further longitudinal studies are needed to assess NPA as a biomarker for progression or regression of DR severity.

Efficacy of bleb-independent penetrating canaloplasty in primary angle-closure glaucoma: one-year results.

PURPOSE: To report the efficacy and safety of bleb-independent penetrating canaloplasty in the management of primary angle-closure glaucoma (PACG). METHODS: This single-centre prospective interventional case series enrolled 57 eyes from 53 PACG patients with medically uncontrolled intraocular pressure (IOP) and peripheral anterior synechiae of over 270°. Penetrating canaloplasty, mainly consisted of tensioning suture-aided Schlemm's canal dilation and a trabeculectomy, was performed to create a direct communication between the anterior chamber and the Schlemm's canal. Postoperative IOP, number of glaucoma medications and procedure-related complications were evaluated. Rate of success was defined as IOP ≤ 21, ≤18 and ≤15 mmHg, and a ≥30% IOP reduction without (complete) or with/without (qualified) IOP-lowering medications. RESULTS: A total of 45 eyes had 360° catheterization successfully completed. The mean preoperative IOP was 33.9 ± 11.7 mmHg (range, 13-59.6 mmHg), on 3.2 ± 0.8 glaucoma medications (range 2-5), which was decreased to 15.4 ± 3.7 mmHg (range, 8.6-22.5) and 0.2 ± 0.6 (range, 0-3) medications at 6 months and 14.8 ± 3.5 mmHg (range, 9-24) and 0.1 ± 0.3 (range, 0-1) medications at 12 months postoperatively. Complete success at 12 months were achieved in 78.9% (95% CI: 0.65-0.93), 71.1% (0.56-0.86) and 50.0% (0.33-0.67) eyes at IOP ≤ 21, ≤18 and ≤15 mmHg, respectively. Transient IOP elevation (>30 mmHg, 26.7%) and hyphema (11.1%) were the most common early surgical complications. CONCLUSION: Penetrating canaloplasty in PACG appeared to have good efficacy and safety profiles in this pilot study. Further studies are justified.

Detection of neovascularisation in the vitreoretinal interface slab using widefield swept-source optical coherence tomography angiography in diabetic retinopathy.

AIMS: To compare the efficacy of diabetic retinal neovascularisation (NV) detection using the widefield swept-source optical coherence tomography angiography (WF SS-OCTA) vitreoretinal interface (VRI) Angio slab and SS-OCT VRI Structure slab. METHODS: A prospective, observational study was performed at Massachusetts Eye and Ear from January 2019 to June 2020. Patients with proliferative diabetic retinopathy (PDR), patients with non-proliferative diabetic retinopathy and patients with diabetes but without diabetic retinopathy were included. All patients were imaged with WF SS-OCTA using the 12×12 mm Angio scan protocol centred on the fovea and optic disc. The en-face SS-OCTA VRI Angio slab and SS-OCT VRI Structure slab were evaluated for the presence or absence of NV. SS-OCTA B-scan was used to classify NV according to cross-sectional morphology (forward, tabletop or flat). All statistical analyses were performed using SPSS V.26.0. RESULTS: One hundred and forty-two eyes of 89 participants were included in the study. VRI Angio detected NV at higher rates compared with VRI Structure (p<0.05). Combining VRI Angio and Structure improved detection rates compared with VRI Angio alone (p<0.05). Due to segmentation errors of the internal limiting membrane, NV with flat morphological classification had lower rates of detection on VRI Angio compared with NV with forward and tabletop morphology (p<0.05). CONCLUSIONS: WF SS-OCTA 12×12 mm VRI Angio and SS-OCT VRI Structure imaging centred on the fovea and optic disc detected NV with high sensitivity and low false positives. The VRI slab may be useful to diagnose and monitor PDR in clinical practice.

Phosphorylation at Ser68 facilitates DCAF11-mediated ubiquitination and degradation of CENP-A during the cell cycle.

CENP-A (centromeric protein A), a histone H3 variant, specifies centromere identity and is essential to centromere maintenance. Little is known about how protein levels of CENP-A are controlled in mammalian cells. Here, we report that the phosphorylation of CENP-A Ser68 primes the ubiquitin-proteasome-mediated proteolysis of CENP-A during mitotic phase in human cultured cells. We identify two major polyubiquitination sites that are responsible for this phosphorylation-dependent degradation. Substituting the two residues, Lys49 and Lys124, with arginines abrogates proper CENP-A degradation and results in CENP-A mislocalization to non-centromeric regions. Furthermore, we find that DCAF11 (DDB1 and CUL4 associated factor 11/WDR23) is the E3 ligase that specifically mediates the observed polyubiquitination. Deletion of DCAF11 hampers CENP-A degradation and causes its mislocalization. We conclude that the Ser68 phosphorylation plays an important role in regulating cellular CENP-A homeostasis via DCAF11-mediated degradation to prevent ectopic localization of CENP-A during the cell cycle.

Surf4 facilitates reprogramming by activating the cellular response to endoplasmic reticulum stress.

OBJECTIVES: Maternal factors that are enriched in oocytes have attracted great interest as possible key factors in somatic cell reprogramming. We found that surfeit locus protein 4 (Surf4), a maternal factor, can facilitate the generation of induced pluripotent stem cells (iPSCs) previously, but the mechanism remains elusive. MATERIALS AND METHODS: In this study, we investigated the function and mechanism of Surf4 in somatic cell reprogramming using a secondary reprogramming system. Alkaline phosphatase (AP) staining, qPCR and immunofluorescence (IF) staining of expression of related markers were used to evaluate efficiency of iPSCs derived from mouse embryonic fibroblasts. Embryoid body and teratoma formation assays were performed to evaluate the differentiation ability of the iPSC lines. RNA-seq, qPCR and western blot analysis were applied to validate the downstream targets of Surf4. RESULTS: Surf4 can significantly facilitate the generation of iPSCs in a proliferation-independent manner. When co-expressed with Oct4, Sox2, Klf4 and c-Myc (OSKM), Surf4 can activate the response to endoplasmic reticulum (ER) stress at the early stage of reprogramming. We further demonstrated that Hspa5, a major ER chaperone, and the active spliced form of Xbp1 (sXbp1), a major mediator of ER stress, can mimic the effects of Surf4 on somatic cell reprogramming. Concordantly, blocking the unfolded protein response compromises the effect of Surf4 on reprogramming. CONCLUSIONS: Surf4 promotes somatic cell reprogramming by activating the response to ER stress.

Nuclear m6A reader YTHDC1 regulates the scaffold function of LINE1 RNA in mouse ESCs and early embryos.

N6-methyladenosine (m6A) on chromosome-associated regulatory RNAs (carRNAs), including repeat RNAs, plays important roles in tuning the chromatin state and transcription, but the intrinsic mechanism remains unclear. Here, we report that YTHDC1 plays indispensable roles in the self-renewal and differentiation potency of mouse embryonic stem cells (ESCs), which highly depends on the m6A-binding ability. Ythdc1 is required for sufficient rRNA synthesis and repression of the 2-cell (2C) transcriptional program in ESCs, which recapitulates the transcriptome regulation by the LINE1 scaffold. Detailed analyses revealed that YTHDC1 recognizes m6A on LINE1 RNAs in the nucleus and regulates the formation of the LINE1-NCL partnership and the chromatin recruitment of KAP1. Moreover, the establishment of H3K9me3 on 2C-related retrotransposons is interrupted in Ythdc1-depleted ESCs and inner cell mass (ICM) cells, which consequently increases the transcriptional activities. Our study reveals a role of m6A in regulating the RNA scaffold, providing a new model for the RNA-chromatin cross-talk.