Ophthalmologies
Abstract
BACKGROUND. A randomized clinical trial from 1984-1992 indicated that vitamin A supplementation had a beneficial effect on the progression of retinitis pigmentosa (RP), while vitamin E had an adverse effect. METHODS. Sequencing of banked DNA samples from that trial provided the opportunity to determine if certain genotypes responded preferentially to vitamin supplementation. RESULTS. The genetic solution rate was 587/765 (77%) of sequenced samples. Combining genetic solutions with electroretinogram outcomes showed that there were systematic differences in severity and progression seen among different genetic subtypes of RP, extending findings made for USH2A, RHO, RPGR, PRPF31, and EYS. Baseline electroretinogram 30Hz flicker implicit time was an independent strong predictor of progression rate. Using additional data and baseline implicit time as a predictor, the deleterious effect of vitamin E was still present. Surprisingly, the effect of vitamin A progression in the cohort as a whole was not detectable, with or without data from subsequent trials. Subgroup analyses are also discussed. CONCLUSION. Overall, genetic subtype and implicit time have significant predictive power for a patient’s rate of progression, which is useful prognostically. While vitamin E supplementation should still be avoided, these data do not support a generalized neuroprotective effect of vitamin A for all types of RP. TRAIL REGISTRATION. ClinicalTrials.gov NCT00000114, NCT00000116, NCT00346333 FUNDING. the Foundation Fighting Blindness and the National Eye Institute: RO1 EY012910 (EAP), R01 EY031036 (JC), R01EY026904 (KMB/EAP), and P30EY014104.
Authors
Jason Comander, Carol Weigel DiFranco, Kit Green Sanderson, Emily M. Place, Matthew Maher, Erin Zampaglione, Yan Zhao, Rachel M. Huckfeldt, Kinga M. Bujakowska, Eric A. Pierce
Abstract
Familial exudative vitreoretinopathy (FEVR) is a complex hereditary eye disorder characterized by incomplete development of the retinal vasculature, thereby affecting retinal angiogenesis. But the genetic factors contributing to its development or pathogenesis remain elusive. In a Chinese FEVR family with 19 members, by utilizing whole exome sequencing, we identified a candidate disease-causing DNA variant in sorting nexin 31 (SNX31) (c.963delG; p. Trp321Cys), which results in a frameshift mutation. Herein we studied the biochemical mechanism of this mutation and uncovered that it is deficient in β1-integrin binding and integrin stability. The SNX31 c.963delG point mutation mouse model (SNX31m/m) was constructed using CRISPR/Cas9 technology. At 2-4 months of age, SNX31m/m mice showed fundus phenotypes similar to FEVR-like changes, including vascular leakage and retinal atrophy. Moreover, we found that VEGF and apoptotic pathways were involved in these ocular phenotypes. At present, the FEVR-like mouse model is mainly constructed by intravitreal injection, and we are the first to construct it by gene knockout. Hence our study extended FEVR mutation spectrum to include SNX31. Meanwhile, these findings expanded our understanding of the molecular pathogenesis of FEVR and may facilitate the development of methods for the diagnosis and prevention of FEVR patients.
Authors
Ningda Xu, Yi Cai, Jiarui Li, Tianchang Tao, Caifei Liu, Yan Shen, Xiaoxin Li, Leiliang Zhang, Mingwei Zhao, Xuan Shi, Jing Li, Lvzhen Huang
Abstract
Patients with neovascular AMD (nAMD) suffer vision loss from destructive angiogenesis, termed choroidal neovascularization (CNV). Macrophages are found in CNV lesions from nAMD patients. Additionally, Ccr2-/- mice, which lack classical monocyte-derived macrophages, show reduced CNV size. However, macrophages are highly diverse cells that can perform multiple functions. We performed single-cell RNA-sequencing on immune cells from wildtype and Ccr2-/- eyes to uncover macrophage heterogeneity during the laser-induced CNV mouse model of nAMD. We identified 12 macrophage clusters, including Spp1+ macrophages. Spp1+ macrophages were enriched from wildtype lasered eyes and expressed a pro-angiogenic transcriptome via multiple pathways, including vascular endothelial growth factor signaling, endothelial cell sprouting, cytokine signaling, and fibrosis. Additionally, Spp1+ macrophages expressed the marker CD11c, and CD11c+ macrophages were increased by laser and present in CNV lesions. Finally, CD11c+ macrophage depletion reduced CNV size by 40%. These findings broaden our understanding of ocular macrophage heterogeneity and implicate CD11c+ macrophages as a potential therapeutic target for treatment-resistant nAMD patients.
Authors
Steven Droho, Amrita Rajesh, Carla M. Cuda, Harris Perlman, Jeremy A. Lavine
Abstract
Pathological angiogenesis is a major cause of irreversible blindness in individuals of all age groups with proliferative retinopathy (PR). Mononuclear phagocytes (MPs) within neovascular areas contribute to aberrant retinal angiogenesis. Due to their cellular heterogeneity, defining the roles of MP subsets in PR onset and progression has been challenging. Here, we aimed to investigate the heterogeneity of microglia associated with neovascularization and characterize the transcriptional profiles and metabolic pathways of pro-angiogenic microglia in a mouse model of oxygen-induced proliferative retinopathy (OIR). Using transcriptional single-cell sorting, we comprehensively map all microglia populations in retinas of room air (RA) and OIR mice. We unveil several unique types of PR-associated microglia (PRAM) and identify markers, signaling pathways, and regulons associated with these cells. Among these microglia subpopulations, we found a highly proliferative microglia subset with high self-renewal capacity and a hyper-metabolic microglia subset that expresses high levels of activating microglia markers, glycolytic enzymes and pro-angiogenic insulin-like growth factor 1. Immunohistochemical staining shows these PRAMs were spatially located within or around neovascular (NV) tufts. These unique microglia-types have the potential to promote retinal angiogenesis, which may have important implications for future treatment of PR and other pathological ocular angiogenesis-related diseases.
Authors
Zhiping Liu, Huidong Shi, Jiean Xu, Qiuhua Yang, Qian Ma, Xiaoxiao Mao, Zhimin Xu, Yaqi Zhou, Qingen Da, Yongfeng Cai, David J.R. Fulton, Zheng Dong, Akrit Sodhi, Ruth B. Caldwell, Yuqing Huo
Abstract
We describe affected members of a two-generation family segregating a Stargardt disease-like phenotype caused by a two base pair deletion-insertion, c.1014_1015delGAinsCT;p(Trp338_Asn339delinsCysTyr), in BEST1. The variant was identified by whole exome sequencing and its pathogenicity was verified through chloride channel recording using wild-type (WT) and transfected mutant HEK293 cells. Clinical examination of both patients revealed a similar phenotype at two different disease stages that were attributable to difference in their age at presentation. Hyperautofluorescent flecks along the arcades were observed in the proband, while the affected mother exhibited more advanced retinal pigment epithelium (RPE) loss in the central macula. Full-field electroretinogram testing was unremarkable in the daughter, however, moderate attenuation of generalized cone function was detected in the mother. Electro-oculogram testing in the daughter was consistent with widespread dysfunction of the RPE characteristic of Best disease. Whole-cell patch clamp recordings revealed statistically significant decrease in chloride conductance of the mutant compared to WT cells. This report broadens the clinical spectrum of BEST1-associated retinopathy in the form of a mother and daughter with BEST1 genotype phenocopying Stargardt disease.
Authors
Masha Kolesnikova, Jin Kyun Oh, Jiali Wang, Winston Lee, Jana Zernant, Pei-Yin Su, Angela H. Kim, Laura A. Jenny, Tingting Yang, Rando Allikmets, Stephen H. Tsang
Abstract
Loss of retinal blood flow autoregulation is an early feature of diabetes that precedes the development of clinically recognizable diabetic retinopathy (DR). Retinal blood flow autoregulation is mediated by the myogenic response of the retinal arterial vessels, a process that is initiated by the stretch‑dependent activation of TRPV2 channels on the retinal vascular smooth muscle cells (VSMCs). Here, we show that the impaired myogenic reaction of retinal arterioles from diabetic animals is associated with a complete loss of stretch‑dependent TRPV2 current activity on the retinal VSMCs. This effect could be attributed, in part, to TRPV2 channel downregulation, a phenomenon that was also evident in human retinal VSMCs from diabetic donors. We also demonstrate that TRPV2 heterozygous rats, a nondiabetic model of impaired myogenic reactivity and blood flow autoregulation in the retina, develop a range of microvascular, glial, and neuronal lesions resembling those observed in DR, including neovascular complexes. No overt kidney pathology was observed in these animals. Our data suggest that TRPV2 dysfunction underlies the loss of retinal blood flow autoregulation in diabetes and provide strong support for the hypothesis that autoregulatory deficits are involved in the pathogenesis of DR.
Authors
Michael O’Hare, Gema Esquiva, Mary K. McGahon, Jose Manuel Romero Hombrebueno, Josy Augustine, Paul Canning, Kevin S. Edgar, Peter Barabas, Thomas Friedel, Patrizia Cincolà, Jennifer Henry, Katie Mayne, Hannah Ferrin, Alan W. Stitt, Timothy J. Lyons, Derek P. Brazil, David J. Grieve, J. Graham McGeown, Tim M. Curtis
Abstract
Familial exudative vitreoretinopathy (FEVR) is a hereditary disorder that can cause vision loss. The CTNND1 gene encodes a cellular adhesion protein p120-catenin (p120), which is essential for vascularization, yet the function of p120 in postnatal physiological angiogenesis remains unclear. Here, we applied whole-exome sequencing (WES) on 140 probands of FEVR families and identified three candidate variants in the human CTNND1 gene. We performed inducible deletion of Ctnnd1 in the postnatal mouse endothelial cells (ECs) and observed typical phenotypes of FEVR. Immunofluorescence of retina flat mounts also revealed immune responses, including reactive astrogliosis and microgliosis accompanied by abnormal Vegfa expression. Using an unbiased proteomics analysis in combination with in vivo or in vitro approaches, we propose that p120 is critical for the integrity of cadherin/catenin complex, and that p120 activates Wnt signaling activity by protecting β-catenin from Gsk3β-ubiquitin-guided degradation. Treatment of CTNND1-depleted HRECs with Gsk3β inhibitors LiCl or CHIR-99021 successfully enhanced cell proliferation by preventing β-catenin from degradation. Moreover, LiCl treatment increased vessel density in Ctnnd1-deficient mouse retinas. Functional analysis also revealed that variants in CTNND1 cause FEVR by compromising the expression of adherens junctions (AJs) and Wnt signaling activity. Additionally, genetic interactions between p120 and β-catenin or α-catenin revealed by double heterozygous deletion in mice further confirmed that p120 regulates vascular development through the Wnt/Cadherin axis. Together, we propose that CTNND1 is a novel candidate gene associated with FEVR, and that variants in CTNND1 can cause FEVR through the Wnt/Cadherin axis.
Authors
Mu Yang, Shujin Li, Li Huang, Rulian Zhao, Erkuan Dai, Xiaoyan Jiang, Yunqi He, Jinglin Lu, Li Peng, Wenjing Liu, Zhaotian Zhang, Dan Jiang, Yi Zhang, Zhilin Jiang, Yeming Yang, Peiquan Zhao, Xianjun Zhu, Xiaoyan Ding, Zhenglin Yang
Abstract
Most patients with neovascular age-related macular degeneration (nvAMD), the leading cause of severe vision loss in elderly Americans, respond inadequately to current therapies targeting a single angiogenic mediator, vascular endothelial growth factor (VEGF). Here we report that aqueous levels of a second vasoactive mediator, angiopoietin-like 4 (ANGPTL4), can help predict the response of nvAMD patients to anti-VEGF therapies. ANGPTL4 expression was higher in patients who required monthly treatment with anti-VEGF therapies compared to patients who could be effectively treated with less frequent injections. We further demonstrate that ANGPTL4 acts synergistically with VEGF to promote the growth and leakage of choroidal neovascular (CNV) lesions in mice. Targeting ANGPTL4 expression was as effective as targeting VEGF expression for treating CNV in mice, while simultaneously targeting both was more effective than targeting either factor alone. To help translate these findings to patients, we used a soluble receptor that binds to both VEGF and ANGPTL4 and effectively inhibited the development of CNV lesions in mice. Our findings provide an assay that can help predict the response of nvAMD patients to anti-VEGF monotherapy and suggest that therapies targeting both ANGPTL4 and VEGF will be a more effective approach for the treatment of this blinding disease.
Authors
Yu Qin, Aumreetam Dinabandhu, Xuan Cao, Jaron C. Sanchez, Kathleen Jee, Murilo Rodrigues, Chuanyu Guo, Jing Zhang, Jordan Vancel, Deepak Menon, Noore-Sabah Khan, Tao Ma, Stephany Y. Tzeng, Yassine J. Daoud, Jordan J. Green, Gregg L. Semenza, Silvia Montaner, Akrit Sodhi
Abstract
Disruption of the neurovascular unit (NVU) underlies the pathophysiology of various CNS diseases.(1-3) One strategy to repair NVU dysfunction would use stem/progenitor cells to provide trophic support to the NVU’s functionally coupled and interdependent vasculature and surrounding CNS parenchyma.(4) A subset of endothelial progenitor cells, endothelial colony forming cells (ECFCs) with high expression of the CD44 hyaluronan receptor (CD44hi), provides such neurovasculotrophic support via a paracrine mechanism.(5) Here, we report that bioactive extracellular vesicles from CD44hi ECFCs (EVshi) are paracrine mediators, recapitulating the effects of intact cell therapy in murine models of ischemic/neurodegenerative retinopathy; vesicles from ECFCs with low expression levels of CD44 (EVslo) were ineffective. Small RNA sequencing comparing the microRNA (miR) cargo from EVshi and EVslo identified candidate miRs that contribute to these effects. EVshi may be used to repair NVU dysfunction through multiple mechanisms to stabilize hypoxic vasculature, promote vascular growth, and support neural cells.
Authors
Kyle V. Marra, Edith Aguilar, Wei Guoqin, Ayumi Usui-Ouchi, Yochiro Ideguchi, Susumu Sakimoto, Martin Friedlander
Abstract
Rhodopsin (RHO)-associated retinitis pigmentosa (RP) is a progressive retinal disease that currently has no cure. RHO protein misfolding leads to disturbed proteostasis and the death of rod photoreceptors, resulting in decreased vision. We previously identified non-retinoid chaperones of RHO, including YC-001 and F5257-0462, by small-molecule high-throughput screening. Here, we profile the chaperone activities of these molecules towards the cell-surface level of 27 RP-causing human RHO mutants in NIH3T3 cells. Further, using retinal explant culture, we show that YC-001 improves retinal proteostasis by supporting RHO homeostasis in RhoP23H/+ mouse retinae, which results in thicker outer nuclear layers (ONL) indicating delayed photoreceptor degeneration. Interestingly, YC-001 ameliorated retinal immune responses and reduced the number of microglia/macrophages in the RhoP23H/+ retinal explants. Similarly, F5257-0462 also protects photoreceptors in RhoP23H/+ retinal explants. In vivo, intravitreal injection of YC-001 or F5257-0462 microparticles in PBS shows that F5257-0462 has a higher efficacy in preserving photoreceptor function and delaying photoreceptor death in RhoP23H/+ mice. Collectively, we provide proof of principle that non-retinoid chaperones are promising drug candidates in treating RHO-associated RP.
Authors
Abhishek Vats, Yibo Xi, Bing Feng, Owen D. Clinger, Anthony J. St. Leger, Xujie Liu, Archisha Ghosh, Chase D. Dermond, Kira L. Lathrop, Gregory P. Tochtrop, Serge Picaud, Yuanyuan Chen
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