Ophthalmology
Abstract
Human pluripotent stem cells (hPSCs) hold great promise for the treatment of various human diseases. However, their therapeutic benefits and mechanisms for treating corneal endothelial dysfunction remain undefined. Here, we developed a therapeutic regimen consisting of the combination of hPSC-derived corneal endothelial precursors (CEPs) with nicotinamide (NAM) for effective treatment of corneal endothelial dysfunction. In rabbit and nonhuman primate models, intracameral injection of CEPs and NAM achieved long-term recovery of corneal clarity and thickness, similar with the therapeutic outcome of cultured human corneal endothelial cells (CECs). The transplanted human CEPs exhibited structural and functional integration with host resident CECs. However, the long-term recovery relied on the stimulation of endogenous endothelial regeneration in rabbits, but predominantly on the replacing function of transplanted cells during the 3-year follow-up in nonhuman primates, which resemble human corneal endothelium with limited regenerative capacity. Mechanistically, NAM ensured in vivo proper maturation of transplanted CEPs into functional CECs by preventing premature senescence and endothelial-mesenchymal transition within the TGF-β–enriched aqueous humor. Together, we provide compelling experimental evidence and mechanistic insights of simultaneous delivery of CEPs and NAM as a potential approach for treating corneal endothelial dysfunction.
Authors
Zongyi Li, Haoyun Duan, Yanni Jia, Can Zhao, Wenjing Li, Xin Wang, Yajie Gong, Chunxiao Dong, Bochao Ma, Shengqian Dou, Bin Zhang, Dongfang Li, Yihai Cao, Lixin Xie, Qingjun Zhou, Weiyun Shi
Abstract
BACKGROUND. To reduce the treatment burden for patients with neovascular age-related macular degeneration (nvAMD), emerging therapies targeting vascular endothelial growth factor (VEGF) are being designed to extend the interval between treatments, thereby minimizing the number of intraocular injections. However, which patients will benefit from longer-acting agents is not clear. METHODS. Eyes with nvAMD (n=122) underwent 3 consecutive monthly injections with currently available anti-VEGF therapies, followed by a treat-and-extend protocol. Patients who remained quiescent 12 weeks from their prior treatment entered a “treatment pause” and were switched to pro re nata (PRN) treatment (based on vision, clinical exam, and/or imaging studies). Proteomic analysis was performed on aqueous fluid to identify proteins that correlate with patients’ response to treatment. RESULTS. At the end of 1 year, 38/122 eyes (31%) entered a treatment pause (≥30 weeks). Conversely, 21/122 eyes (17%) failed extension and required monthly treatment at the end of year 1. Proteomic analysis of aqueous fluid identified proteins that correlated with patients’ response to treatment including proteins previously implicated in AMD pathogenesis. Interestingly, apolipoprotein-B100 (ApoB100), a principal component of drusen implicated in the progression of non-neovascular AMD, was increased in treated patients who required less frequent injections. ApoB100 expression was higher in AMD eyes compared to controls but was lower in eyes that develop choroidal neovascularization (CNV), consistent with a protective role. Accordingly, mice over-expressing ApoB100 were partially protected from laser-induced CNV. CONCLUSIONS. Aqueous biomarkers could help identify nvAMD patients who may not require – nor benefit from – long-term treatment with anti-VEGF therapy.
Authors
Xuan Cao, Jaron Castillo Sanchez, Aumreetam Dinabandhu, Chuanyu Guo, Tapan P. Patel, Zhiyong Yang, Ming-Wen Hu, Lijun Chen, Yuefan Wang, Danyal Malik, Kathleen Jee, Yassine J. Daoud, James T. Handa, Hui Zhang, Jiang Qian, Silvia Montaner, Akrit Sodhi
Abstract
BACKGROUND. Noninvasive assessment of metabolic processes that sustain regeneration of human retinal visual pigments (visual cycle) is essential to improve ophthalmic diagnostics and to accelerate development of new treatments to counter retinal diseases. Fluorescent vitamin A derivatives, which are the chemical intermediates of these processes, are highly sensitive to UV light; thus, safe analyses of these processes in humans are currently beyond the reach of even the most modern ocular imaging modalities. METHODS. We present a compact fluorescence scanning laser ophthalmoscope (TPEF-SLO) and spectrally resolved images of the human retina based on two-photon excitation (TPE) with near-infrared (IR) light. A custom Er:fiber laser with integrated pulse selection, along with intelligent post-processing of data, enables excitation with low laser power and precise measurement of weak signals. RESULTS. We demonstrate spectrally resolved TPE fundus images of human subjects. Comparison of TPE data between human and mouse models of retinal diseases revealed similarity with mouse models that rapidly accumulate bisretinoid condensation products. Thus, visual cycle intermediates and toxic byproducts of this metabolic pathway can be measured and quantified by TPE imaging. CONCLUSION. Our work establishes a TPE instrument and measurement method for noninvasive metabolic assessment of the human retina. This approach opens the possibility for monitoring eye diseases in the earliest stages before structural damage to the retina occurs. FUNDING. NIH, Research to Prevent Blindness, Foundation for Polish Science, European Regional Development Fund, Polish National Agency for Academic Exchange and Polish Ministry of Science and Higher Education.
Authors
Jakub Boguslawski, Grazyna Palczewska, Slawomir Tomczewski, Jadwiga Milkiewicz, Piotr Kasprzycki, Dorota Stachowiak, Katarzyna Komar, Marcin J. Marzejon, Bartosz L. Sikorski, Arkadiusz Hudzikowski, Aleksander Głuszek, Zbigniew Łaszczych, Karol Karnowski, Grzegorz Soboń, Krzysztof Palczewski, Maciej Wojtkowski
Abstract
BACKGROUND. A long-held dream of scientists is to transfer information directly to the visual cortex of blind individuals, thereby restoring a rudimentary form of sight. However, no clinically available cortical visual prosthesis yet exists. METHODS.We implanted an intracortical microelectrode array consisting of 96 electrodes in the visual cortex of a 57-year-old person with complete blindness for a six- month period. We measured thresholds and the characteristics of the visual percepts elicited by intracortical microstimulation. RESULTS. Implantation and subsequent explantation of intracortical microelectrodes were carried out without complications. The mean stimulation threshold for single electrodes was 66.8 ± 36.5 μA. We consistently obtained high-quality recordings from visually deprived neurons and the stimulation parameters remained stable over time. Simultaneous stimulation via multiple electrodes were associated with a significant reduction in thresholds (p<0.001, ANOVA test) and evoked discriminable phosphene percepts, allowing the blind participant to identify some letters and recognize object boundaries. Furthermore, we observed a learning process that helped the subject to recognize complex patterns over time. CONCLUSIONS. Our results demonstrate the safety and efficacy of chronic intracortical microstimulation via a large number of electrodes in human visual cortex, showing its high potential for restoring functional vision in the blind. TRIAL REGISTRATION. ClinicalTrials.gov identifier NCT02983370. FUNDING. Funding was provided by grant RTI2018-098969-B-100 from the Spanish Ministerio de Ciencia Innovación y Universidades, by grant PROMETEO/2019/119 from the Generalitat Valenciana (Spain), by the Bidons Egara Research Chair of the University Miguel Hernández (Spain) and by the John Moran Eye Center of the University of Utah (US).
Authors
Eduardo Fernández, Arantxa Alfaro, Cristina Soto-Sánchez, Pablo González-López, Antonio M. Lozano Ortega, Sebastian Peña, María Dolores Grima, Alfonso Rodil, Bernardeta Gómez, Xing Chen, Pieter R. Roelfsema, John D. Rolston, Tyler S. Davis, Richard A. Normann
Abstract
Therapies targeting VEGF have proven only modestly effective for the treatment of proliferative sickle cell retinopathy (PSR), the leading cause of blindness in patients with sickle cell disease. Here, we shift our attention upstream from the genes that promote retinal neovascularization (NV) to the transcription factors that regulate their expression. We demonstrated increased expression of HIF-1α and HIF-2α in the ischemic inner retina of PSR eyes. Although both HIFs participated in promoting VEGF expression by hypoxic retinal Müller cells, HIF-1 alone was sufficient to promote retinal NV in mice, suggesting that therapies targeting only HIF-2 would not be adequate to prevent PSR. Nonetheless, administration of a HIF-2–specific inhibitor currently in clinical trials (PT2385) inhibited NV in the oxygen-induced retinopathy (OIR) mouse model. To unravel these discordant observations, we examined the expression of HIFs in OIR mice and demonstrated rapid but transient accumulation of HIF-1α but delayed and sustained accumulation of HIF-2α; simultaneous expression of HIF-1α and HIF-2α was not observed. Staggered HIF expression was corroborated in hypoxic adult mouse retinal explants but not in human retinal organoids, suggesting that this phenomenon may be unique to mice. Using pharmacological inhibition or an in vivo nanoparticle-mediated RNAi approach, we demonstrated that inhibiting either HIF was effective for preventing NV in OIR mice. Collectively, these results explain why inhibition of either HIF-1α or HIF-2α is equally effective for preventing retinal NV in mice but suggest that therapies targeting both HIFs will be necessary to prevent NV in patients with PSR.
Authors
Jing Zhang, Yaowu Qin, Mireya Martinez, Miguel Flores-Bellver, Murilo Rodrigues, Aumreetam Dinabandhu, Xuan Cao, Monika Deshpande, Yu Qin, Silvia Aparicio-Domingo, Yuan Rui, Stephany Y. Tzeng, Shaima Salman, Jin Yuan, Adrienne W. Scott, Jordan J. Green, M. Valeria Canto-Soler, Gregg L. Semenza, Silvia Montaner, Akrit Sodhi
Abstract
Leber’s hereditary optic neuropathy (LHON) is a maternally inherited eye disease. X-linked nuclear modifiers were proposed to modify the phenotypic manifestation of LHON-associated mitochondrial DNA (mtDNA) mutations. By whole exome sequencing, we identified the X-linked LHON modifier (c.157C>T, p. Arg53Trp) in the PRICKLE3 encoding a mitochondrial protein linked to biogenesis of ATPase in three Chinese families. All affected individuals carried both ND4 11778G>A and p.Arg53Trp mutations, while subjects bearing only single mutation exhibited normal vision. The cells carrying the p.Arg53Trp mutation exhibited the defective assembly, stability and function of ATP synthase, verified by PRICKLE3 knock-down cells. Co-immunoprecipitation indicated the direct interaction of PRICKLE3 with ATP synthase via ATP8. Strikingly, mutant cells bearing both p.Arg53Trp and m.11778G>A mutations displayed greater mitochondrial dysfunctions than those carrying only single mutation. These indicated that the p.Arg53Trp mutation acted in synergy with m.11778G>A mutation and deteriorated mitochondrial dysfunctions necessary for the expression of LHON. Furthermore, we demonstrated that Prickle3 deficient mice exhibited the pronounced ATPase deficiencies. Prickle3 knock-out mice recapitulated LHON phenotypes with retina deficiencies including degeneration of retinal ganglion cells and abnormal vasculature. Our findings provided new insights into pathophysiology of LHON that were manifested by interaction between mtDNA mutation and X-linked nuclear modifier.
Authors
Jialing Yu, Xiaoyang Liang, Yanchun Ji, Cheng Ai, Junxia Liu, Ling Zhu, Zhipeng Nie, Xiaofen Jin, Chenghui Wang, Juanjuan Zhang, Fuxin Zhao, Shuang Mei, Xiaoxu Zhao, Xiangtian Zhou, Minglian Zhang, Meng Wang, Taosheng Huang, Pingping Jiang, Min-Xin Guan
Abstract
Retinitis pigmentosa (RP) is a genetically heterogenous group of eye diseases in which initial degeneration of rods triggers secondary degeneration of cones, leading to significant loss of daylight, color, and high-acuity vision. Gene complementation with adeno-associated viral (AAV) vectors is one strategy to treat RP. Its implementation faces substantial challenges, however — e.g., the tremendous number of loci with causal mutations. Gene therapy targeting secondary cone degeneration is an alternative approach that could provide a much-needed generic treatment for many RP patients. Here, we show that microglia are required for the upregulation of potentially neurotoxic inflammatory factors during cone degeneration in RP, creating conditions that might contribute to cone dysfunction and death. To ameliorate the effects of such factors, we used AAV vectors to express isoforms of the anti-inflammatory cytokine transforming growth factor-beta (TGF-β). AAV-mediated delivery of TGF-β1 rescued degenerating cones in three mouse models of RP carrying different pathogenic mutations. Treatment with TGF-β1 protected vision, as measured by two behavioral assays, and could be pharmacologically disrupted by either depleting microglia or blocking the TGF-β receptors. Our results suggest that TGF-β1 may be broadly beneficial for patients with cone degeneration, and potentially other forms of neurodegeneration, through a pathway dependent upon microglia.
Authors
Sean K. Wang, Yunlu Xue, Constance L. Cepko
Abstract
Diabetic retinopathy (DR) is the leading cause of blindness in working-age adults. Vascular pericyte degeneration is the predominant clinical manifestation of DR, yet the mechanism governing pericyte degeneration is poorly understood. Circular RNAs (circRNAs) play important roles in multiple biological processes and disease progression. Here, we investigated the role of circRNA in pericyte biology and diabetes-induced retinal vascular dysfunction. cZNF532 expression was upregulated in pericytes under diabetic stress, in the retinal vessels of a diabetic murine model, and in the vitreous humor of diabetic patients. cZNF532 silencing reduced the viability, proliferation, and differentiation of pericytes and suppressed the recruitment of pericytes toward endothelial cells in vitro. cZNF532 regulated pericyte biology by acting as a miR-29a-3p sponge and inducing increased expression of NG2, LOXL2, and CDK2. Knockdown of cZNF532 or overexpression of miR-29a-3p aggravated streptozotocin-induced retinal pericyte degeneration and vascular dysfunction. By contrast, overexpression of cZNF532 or inhibition of miR-29a-3p ameliorated human diabetic vitreous-induced retinal pericyte degeneration and vascular dysfunction. Collectively, these data identify a circRNA-mediated mechanism that coordinates pericyte biology and vascular homeostasis in DR. Induction of cZNF532 or antagonism of miR-29a-3p is an exploitable therapeutic approach for the treatment of DR.
Authors
Qin Jiang, Chang Liu, Chaopeng Li, Shanshan Xu, Mudi Yao, Huimin Ge, Yanan Sun, Xiumiao Li, Shujie Zhang, Kun Shan, Baihui Liu, Jin Yao, Chen Zhao, Biao Yan
Abstract
Background: In retinitis pigmentosa (RP) rod photoreceptors degenerate from one of many mutations after which cones are compromised by oxidative stress. N-acetylcysteine (NAC) reduces oxidative damage and increases cone function/survival in RP models. We tested the safety, tolerability, and visual function effects of oral NAC in RP patients. Methods: Subjects (n = 10 per cohort) received 600 mg (cohort 1), 1200 mg (cohort 2), or 1800 mg (cohort 3) NAC BID for 12 weeks and then TID for 12 weeks. Best-corrected visual acuity (BCVA), macular sensitivity, ellipsoid zone (EZ) width, and aqueous NAC were measured. Linear mixed effects models were used to estimate the rates of changes during the treatment period. Results: There were 9 drug-related gastrointestinal adverse events which resolved spontaneously or with dose reduction (MTD 1800 mg bid). During the 24 week treatment period, mean BCVA significantly improved at 0.4 (95% CI 0.2–0.6, P < 0.001), 0.5 (95% CI 0.3–0.7, P < 0.001) and 0.2 (95% CI 0.02–0.4, P = 0.03) letters/month in cohorts 1, 2 and 3, respectively. There was no significant improvement in mean sensitivity (MS) over time in cohorts 1 and 2, but there was in cohort 3 (0.15 dB/month, 95%CI 0.04–0.26). There was no significant change in mean EZ width in any cohort. Conclusion: Oral NAC is safe and well-tolerated in patients with moderately advanced RP and may improve suboptimally functioning macular cones. A randomized, placebo-controlled trial is needed to determine if oral NAC can provide long term stabilization and/or improvement in visual function in patients with RP.
Authors
Peter A. Campochiaro, Mustafa Iftikhar, Gulnar Hafiz, Anam Akhlaq, Grace Tsai, Dagmar Wehling, Lili Lu, G. Michael Wall, Mandeep S. Singh, Xiangrong Kong
Abstract
Increases in the number of cell therapies in the preclinical and clinical phases have prompted the need for reliable and non-invasive assays to validate transplant function in clinical biomanufacturing. We developed a robust characterization methodology composed of quantitative bright-field absorbance microscopy (QBAM) and deep neural networks (DNNs) to non-invasively predict tissue function and cellular donor identity. The methodology was validated using clinical-grade induced pluripotent stem cell derived retinal pigment epithelial cells (iPSC-RPE). QBAM images of iPSC-RPE were used to train DNNs that predicted iPSC-RPE monolayer transepithelial resistance, predicted polarized vascular endothelial growth factor (VEGF) secretion, and matched iPSC-RPE monolayers to the stem cell donors. DNN predictions were supplemented with traditional machine learning algorithms that identified shape and texture features of single cells that were used to predict tissue function and iPSC donor identity. These results demonstrate non-invasive cell therapy characterization can be achieved with QBAM and machine learning.
Authors
Nicholas J. Schaub, Nathan A. Hotaling, Petre Manescu, Sarala Padi, Qin Wan, Ruchi Sharma, Aman George, Joe Chalfoun, Mylene Simon, Mohamed Ouladi, Carl G. Simon, Jr., Peter Bajcsy, Kapil Bharti
Copyright © 2022 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)