Ziming Luo

All Publications

• Tppp3 is a novel molecule for retinal ganglion cell identification and optic nerve regeneration. Acta neuropathologica communications Rao, M., Luo, Z., Liu, C. C., Chen, C. Y., Wang, S., Nahmou, M., Tanasa, B., Virmani, A., Byrne, L., Goldberg, J. L., Sahel, J. A., Chang, K. C. 2024; 12 (1): 204

  Abstract

  Mammalian central nervous system (CNS) axons cannot spontaneously regenerate after injury, creating an unmet need to identify molecular regulators to promote axon regeneration and reduce the lasting impact of CNS injuries. While tubulin polymerization promoting protein family member 3 (Tppp3) is known to promote axon outgrowth in amphibians, its role in mammalian axon regeneration remains unknown. Here we investigated Tppp3 in retinal ganglion cells (RGCs) neuroprotection and axonal regeneration using an optic nerve crush (ONC) model in the rodent. Single-cell RNA sequencing identified the expression of Tppp3 in RGCs of mice, macaques, and humans. Tppp3 overexpression enhanced neurite outgrowth in mouse primary RGCs in vitro, promoted axon regeneration, and improved RGC survival after ONC. Bulk RNA sequencing indicated that Tppp3 overexpression upregulates axon regeneration genes such as Bmp4 and neuroinflammatory pathways. Our findings advance regenerative medicine by developing a new therapeutic strategy for RGC neuroprotection and axon regeneration.

  View details for DOI 10.1186/s40478-024-01917-6

  View details for PubMedID 39734233

  View details for PubMedCentralID 8931466

• Establishment of a Disease Model Using Patient-Specific Induced Pluripotent Stem Cells-Derived Trabecular Meshwork Cells in a Chinese Primary Open-Angle Glaucoma Mega-Pedigree. Discovery medicine Rong, H., Luo, Z., Tang, M., Tang, J., Li, K., Yang, R., Fan, Z., Sun, N., Ge, J. 2024; 36 (189): 2013-2025

  Abstract

  Primary open-angle glaucoma (POAG) is one of the most common insidious blinding eye diseases. Understanding the pathogenic mechanisms of it is extremely important. It is accepted that POAG attacks specific ocular tissue, such as trabecular meshwork and optic nerve damage, which causes elevated intraocular pressure and optic nerve damage. This study aimed to develop a preliminary prediction model for this disease by establishing the patient-specific induced pluripotent stem cells (iPSCs)-derived trabecular meshwork cells (TMCs) (p-iPSCs-TMCs) in the largest POAG family named "GZ.1" in China and preliminarily analyze the pathogenic mechanisms.Peripheral blood of patients in GZ.1 and healthy individuals not belonging to the family were collected and reprogrammed into iPSCs. Then, the iPSCs were differentiated into iPSCs-TMCs. Next, their morphology and function were compared. Finally, their pathogenic mechanisms were analyzed.The patient-specific iPSCs (p-iPSCs) and healthy individual-specific iPSCs (n-iPSCs) were all successfully generated. Their morphology was quite similar to each other. However, p-iPSCs-TMCs exhibited compromised morphology and function. p-iPSCs-TMCs displayed the morphology of heterogeneous distribution and accumulation in clusters, while n-iPSCs-derived TMCs (n-iPSCs-TMCs) showed a uniformly distributed and homogenous appearance. Moreover, p-iPSCs-TMCs showed greater cell apoptosis (p < 0.01), impaired proliferating ability (24-h and 48-h time points: p < 0.05, 72-h and 96-h time points: p < 0.001), production of reactive oxygen species (p < 0.05), and impaired phagocytosis ability than n-iPSCs-TMCs (24-h, 48-h, and 72-h time points: p < 0.0001, 96-h time point: p < 0.001).The p-iPSCs-TMCs can be successfully differentiated from peripheral blood, while the cells show impaired morphology and function compared with n-iPSCs-TMCs. Given this, p-iPSCs-TMCs can serve as an ideal disease model for POAG in GZ.1. Our study on the morphology and function of iPSCs-TMCs in GZ.1 may provide a valuable tool for elucidating the pathogenesis of POAG.

  View details for DOI 10.24976/Discov.Med.202436189.185

  View details for PubMedID 39463221

• Gene regulatory roles of growth and differentiation factors in retinal development. iScience Luo, Z., Shah, S., Tanasa, B., Chang, K. C., Goldberg, J. L. 2024; 27 (6): 110100

  Abstract

  Retinal ganglion cell (RGC) differentiation is tightly controlled by extrinsic and intrinsic factors. Growth and differentiation factor 15 (GDF-15) promotes RGC differentiation, opposite to GDF-11 which inhibits RGC differentiation, both in the mouse retina and in human stem cells. To deepen our understanding of how these two closely related molecules confer opposing effects on retinal development, here we assess the transcriptional profiles of mouse retinal progenitors exposed to exogenous GDF-11 or -15. We find a dichotomous effect of GDF-15 on RGC differentiation, decreasing RGCs expressing residual pro-proliferative genes and increasing RGCs expressing non-proliferative genes, suggestive of greater RGC maturation. Furthermore, GDF-11 promoted the differentiation of photoreceptors and amacrine cells. These data enhance our understanding of the mechanisms underlying the differentiation of RGCs and photoreceptors from retinal progenitors and suggest new approaches to the optimization of protocols for the differentiation of these cell types.

  View details for DOI 10.1016/j.isci.2024.110100

  View details for PubMedID 38947520

  View details for PubMedCentralID PMC11214324

• A potential therapeutic target for optic nerve regeneration Rao, M., Luo, Z., Liu, C., Nahmou, M., Tanasa, B., Virmani, A., Byrne, L., Goldberg, J., Sahel, J., Chang, K. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2024

  View details for Web of Science ID 001312227707102

• Ca<SUP>2+</SUP> /calmodulin-dependent protein kinase II enhances retinal ganglion cell survival but suppresses axon regeneration after optic nerve injury Xia, X., Shi, C., Tsien, C., Sun, C. B., Xie, L., Luo, Z., Bian, M., Russano, K., Thakur, H., Benowitz, L., Goldberg, J., Kapiloff, M. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2024

  View details for Web of Science ID 001313316200208

• Pre-adhesion promotes human stem cell-derived retinal ganglion cell integration after transplant Luo, Z., Xia, X., Nahmou, M., Tsien, C., Bian, M., Huie, E., Goldberg, J. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2024

  View details for Web of Science ID 001312227704185

• Cell replacement with stem cell-derived retinal ganglion cells from different protocols NEURAL REGENERATION RESEARCH Luo, Z., Chang, K. 2024; 19 (4): 807-810

  View details for DOI 10.4103/1673-5374.381494

  View details for Web of Science ID 001064661300023

• Cell replacement with stem cell-derived retinal ganglion cells from different protocols. Neural regeneration research Luo, Z., Chang, K. C. 2024; 19 (4): 807-810

  Abstract

  Glaucoma, characterized by a degenerative loss of retinal ganglion cells, is the second leading cause of blindness worldwide. There is currently no cure for vision loss in glaucoma because retinal ganglion cells do not regenerate and are not replaced after injury. Human stem cell-derived retinal ganglion cell transplant is a potential therapeutic strategy for retinal ganglion cell degenerative diseases. In this review, we first discuss a 2D protocol for retinal ganglion cell differentiation from human stem cell culture, including a rapid protocol that can generate retinal ganglion cells in less than two weeks and focus on their transplantation outcomes. Next, we discuss using 3D retinal organoids for retinal ganglion cell transplantation, comparing cell suspensions and clusters. This review provides insight into current knowledge on human stem cell-derived retinal ganglion cell differentiation and transplantation, with an impact on the field of regenerative medicine and especially retinal ganglion cell degenerative diseases such as glaucoma and other optic neuropathies.

  View details for DOI 10.4103/1673-5374.381494

  View details for PubMedID 37843215

• Ca2+/Calmodulin-Dependent Protein Kinase II Enhances Retinal Ganglion Cell Survival But Suppresses Axon Regeneration after Optic Nerve Injury. eNeuro Xia, X., Shi, C., Tsien, C., Sun, C. B., Xie, L., Luo, Z., Bian, M., Russano, K., Thakur, H. S., Benowitz, L. I., Goldberg, J. L., Kapiloff, M. S. 2024; 11 (3)

  Abstract

  Neuroprotection after injury or in neurodegenerative disease remains a major goal for basic and translational neuroscience. Retinal ganglion cells (RGCs), the projection neurons of the eye, degenerate in optic neuropathies after axon injury, and there are no clinical therapies to prevent their loss or restore their connectivity to targets in the brain. Here we demonstrate a profound neuroprotective effect of the exogenous expression of various Ca2+/calmodulin-dependent protein kinase II (CaMKII) isoforms in mice. A dramatic increase in RGC survival following the optic nerve trauma was elicited by the expression of constitutively active variants of multiple CaMKII isoforms in RGCs using adeno-associated viral (AAV) vectors across a 100-fold range of AAV dosing in vivo. Despite this neuroprotection, however, short-distance RGC axon sprouting was suppressed by CaMKII, and long-distance axon regeneration elicited by several pro-axon growth treatments was likewise inhibited even as CaMKII further enhanced RGC survival. Notably, in a dose-escalation study, AAV-expressed CaMKII was more potent for axon growth suppression than the promotion of survival. That diffuse overexpression of constitutively active CaMKII strongly promotes RGC survival after axon injury may be clinically valuable for neuroprotection per se. However, the associated strong suppression of the optic nerve axon regeneration demonstrates the need for understanding the intracellular domain- and target-specific CaMKII activities to the development of CaMKII signaling pathway-directed strategies for the treatment of optic neuropathies.

  View details for DOI 10.1523/ENEURO.0478-23.2024

  View details for PubMedID 38548335

• Therapeutic strategies for glaucoma and optic neuropathies. Molecular aspects of medicine Lo, J., Mehta, K., Dhillon, A., Huang, Y. K., Luo, Z., Nam, M. H., Al Diri, I., Chang, K. C. 2023; 94: 101219

  Abstract

  Glaucoma is a neurodegenerative eye disease that causes permanent vision impairment. The main pathological characteristics of glaucoma are retinal ganglion cell (RGC) loss and optic nerve degeneration. Glaucoma can be caused by elevated intraocular pressure (IOP), although some cases are congenital or occur in patients with normal IOP. Current glaucoma treatments rely on medicine and surgery to lower IOP, which only delays disease progression. First-line glaucoma medicines are supported by pharmacotherapy advancements such as Rho kinase inhibitors and innovative drug delivery systems. Glaucoma surgery has shifted to safer minimally invasive (or microinvasive) glaucoma surgery, but further trials are needed to validate long-term efficacy. Further, growing evidence shows that adeno-associated virus gene transduction and stem cell-based RGC replacement therapy hold potential to treat optic nerve fiber degeneration and glaucoma. However, better understanding of the regulatory mechanisms of RGC development is needed to provide insight into RGC differentiation from stem cells and help choose target genes for viral therapy. In this review, we overview current progress in RGC development research, optic nerve fiber regeneration, and human stem cell-derived RGC differentiation and transplantation. We also provide an outlook on perspectives and challenges in the field.

  View details for DOI 10.1016/j.mam.2023.101219

  View details for PubMedID 37839232

• Retinal ganglion cell repopulation for vision restoration in optic neuropathy: a roadmap from the RReSTORe Consortium. Molecular neurodegeneration Soucy, J. R., Aguzzi, E. A., Cho, J., Gilhooley, M. J., Keuthan, C., Luo, Z., Monavarfeshani, A., Saleem, M. A., Wang, X., Wohlschlegel, J., RReSTORe Consortium, Baranov, P., Di Polo, A., Fortune, B., Gokoffski, K. K., Goldberg, J. L., Guido, W., Kolodkin, A. L., Mason, C. A., Ou, Y., Reh, T. A., Ross, A. G., Samuels, B. C., Welsbie, D., Zack, D. J., Johnson, T. V., Fouda, A. Y., Ashok, A., Moshiri, A., Chedotal, A., Reed, A. A., Askary, A., Su, A. A., La Torre, A., Jalligampala, A., Silva-Lepe, A., Das, A., Wirostko, B., Frankfort, B. J., Sivyer, B., Alapure, B., Young, B., Clark, B., Jones, B. W., Hellmer, C., Mitchell, C., Ufongene, C., Goldman, D., Feldheim, D., Gutmann, D. H., Calkins, D. J., Krizaj, D., Gamm, D. M., Lozano, D. C., Bovenkamp, D. E., Chen, D. F., Cordero, E. V., Trakhtenberg, E. F., Tian, F., Zhou, F., McLellan, G. J., Quigley, H. A., Serhan, H. A., Tribble, J. R., Meyer, J., Gross, J., Mumm, J. S., Sivak, J. M., Zhang, J. S., Do, J. L., Crowston, J., Chen, J., McGregor, J., Vinnakota, K. C., Huang, K., Peynshaert, K., Uyhazi, K. E., Martin, K., Muller, K., Park, K. K., Cho, K., Chang, K., Benowitz, L., Levin, L. A., Todd, L., De Groef, L., Moons, L., Alarcon-Martinez, L., Singh, M. S., Vidal-Sanz, M., Silveira, M. S., Pavlou, M., Veldman, M. B., Van Hook, M., Samuel, M., Hu, M., Peng, M., Young, M., Cayouette, M., Geranmayeh, M. H., Woodworth, M., Vetter, M., Marsh-Armstrong, N. R., Williams, P. A., Rasiah, P. K., Subramanian, P., Cui, Q. N., Sappington, R. M., Amine, R., Eva, R., Johnston, R. J., Giger, R. J., Ethier, R., Abed, S., Momin, S. N., Blackshaw, S., Liddelow, S. A., Mary, S., Atolagbe, S., Varadarajan, S., Nabhan, T. I., Khatib, T., Sharma, T. P., Brunner, T., Greenwell, T., Rex, T. S., Watkins, T., Badea, T. C., Vrathasha, V., Chavali, V. R., Oliveira-Valenca, V. M., Tai, W. L., Batchelor, W. M., Yang, X., Park, Y., Pan, Y. 2023; 18 (1): 64

  Abstract

  Retinal ganglion cell (RGC) death in glaucoma and other optic neuropathies results in irreversible vision loss due to the mammalian central nervous system's limited regenerative capacity. RGC repopulation is a promising therapeutic approach to reverse vision loss from optic neuropathies if the newly introduced neurons can reestablish functional retinal and thalamic circuits. In theory, RGCs might be repopulated through the transplantation of stem cell-derived neurons or via the induction of endogenous transdifferentiation. The RGC Repopulation, Stem Cell Transplantation, and Optic Nerve Regeneration (RReSTORe) Consortium was established to address the challenges associated with the therapeutic repair of the visual pathway in optic neuropathy. In 2022, the RReSTORe Consortium initiated ongoing international collaborative discussions to advance the RGC repopulation field and has identified five critical areas of focus: (1) RGC development and differentiation, (2) Transplantation methods and models, (3) RGC survival, maturation, and host interactions, (4) Inner retinal wiring, and (5) Eye-to-brain connectivity. Here, we discuss the most pertinent questions and challenges that exist on the path to clinical translation and suggest experimental directions to propel this work going forward. Using these five subtopic discussion groups (SDGs) as a framework, we suggest multidisciplinary approaches to restore the diseased visual pathway by leveraging groundbreaking insights from developmental neuroscience, stem cell biology, molecular biology, optical imaging, animal models of optic neuropathy, immunology & immunotolerance, neuropathology & neuroprotection, materials science & biomedical engineering, and regenerative neuroscience. While significant hurdles remain, the RReSTORe Consortium's efforts provide a comprehensive roadmap for advancing the RGC repopulation field and hold potential for transformative progress in restoring vision in patients suffering from optic neuropathies.

  View details for DOI 10.1186/s13024-023-00655-y

  View details for PubMedID 37735444

• Pre-Adhesion Promotes Cell Survival and Axon Regeneration After Stem Cell-Derived RGC Transplant Luo, Z., Xia, X., Nahmou, M., Tsien, C., Goldberg, J. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2023

  View details for Web of Science ID 001053795603143

• Mitomycin C-loaded PTMC15-F127-PTMC15 hydrogel maintained better bleb function after filtering glaucoma surgery in monkeys with intraocular hypertension. RSC advances Tu, S., Luo, Z., Yang, R., Hu, D., Xian, B., Zhao, F., Ge, J. 2023; 13 (20): 13604-13615

  Abstract

  There is an unmet need for a safer and more effective approach for antimetabolite application to prevent bleb fibrosis after glaucoma filtering surgery. Here, we utilized our previously developed thermosensitive sustained-release agent, mitomycin C-loaded poly(trimethylene carbonate)15-F127-poly(trimethylene carbonate)15 (MMC-hydrogel), aiming to further evaluate the efficacy and safety of MMC-hydrogel in high intraocular pressure (IOP) primate eyes. Twelve primate eyes after high IOP induction were randomly divided into three groups, which respectively received phosphate-buffered saline (PBS)-hydrogel, MMC-hydrogel, and MMC treatment during trabeculectomy. IOP and bleb volume were measured using a Tonopen and anterior segment optical coherence tomography over 28 days. At the end of the experiment, all experimental primate eyes were enucleated. Histopathology and immunohistochemistry were performed to reveal myofibroblast cells and collagen deposition of filtering blebs. The MMC-hydrogel group had satisfactory IOP control (9.25 ± 4.80 mmHg) and maintained well-functioning blebs for a longer time. Fibrosis and scarring were significantly alleviated in this MMC-hydrogel group. There was no obvious toxicity to ocular surfaces or intraocular structures. Taken together, these data suggest that PTMC15-F127-PTMC15-loaded MMC-hydrogel plays a role in functional maintenance and scarring inhibition, showing high efficacy in reducing post-filtering surgery bleb fibrosis. This MMC-hydrogel may offer a new solution for filtering bleb management after glaucoma surgery.

  View details for DOI 10.1039/d3ra01002c

  View details for PubMedID 37152569

  View details for PubMedCentralID PMC10155495

• Kif5a Regulates Mitochondrial Transport in Developing Retinal Ganglion Cells In Vitro. Investigative ophthalmology & visual science Yokota, S., Shah, S. H., Huie, E. L., Wen, R. R., Luo, Z., Goldberg, J. L. 2023; 64 (3): 4

  Abstract

  Axon transport of organelles and neurotrophic factors is necessary for maintaining cellular function and survival of retinal ganglion cells (RGCs). However, it is not clear how trafficking of mitochondria, essential for RGC growth and maturation, changes during RGC development. The purpose of this study was to understand the dynamics and regulation of mitochondrial transport during RGC maturation using acutely purified RGCs as a model system.Primary RGCs were immunopanned from rats of either sex during three stages of development. MitoTracker dye and live-cell imaging were used to quantify mitochondrial motility. Analysis of single-cell RNA sequencing was used to identify Kinesin family member 5A (Kif5a) as a relevant motor candidate for mitochondrial transport. Kif5a expression was manipulated with either short hairpin RNA (shRNA) or exogenous expression adeno-associated virus viral vectors.Anterograde and retrograde mitochondrial trafficking and motility decreased through RGC development. Similarly, the expression of Kif5a, a motor protein that transports mitochondria, also decreased during development. Kif5a knockdown decreased anterograde mitochondrial transport, while Kif5a expression increased general mitochondrial motility and anterograde mitochondrial transport.Our results suggested that Kif5a directly regulates mitochondrial axonal transport in developing RGCs. Future work exploring the role of Kif5a in vivo in RGCs is indicated.

  View details for DOI 10.1167/iovs.64.3.4

  View details for PubMedID 36862119

• Characterization of Primary Cilia Formation in Human ESC-Derived Retinal Organoids. Stem cells international Ning, K., Luo, Z., Kowal, T. J., Tran, M., Majumder, R., Jarin, T. M., Wu, A. Y., Goldberg, J. L., Sun, Y. 2023; 2023: 6494486

  Abstract

  Objectives: Primary cilia are conserved organelles found in polarized mammalian cells that regulate neuronal growth, migration, and differentiation. Proper cilia formation is essential during eye development. Our previous reports found that both amacrine and retinal ganglion cells (RGCs) contain primary cilia in primate and rodent retinas. However, whether primary cilia are present in the inner retina of human retinal organoids remains unknown. The purpose of this study is to characterize the primary cilia distribution in human embryonic stem cell (hESC-derived retinal organoid development.Materials and Methods: Retinal organoids were differentiated from a hESC line, harvested at various developmental timepoints (day 44-day 266), and immunostained with antibodies for primary cilia, including Arl13b (for the axoneme), AC3, and Centrin3 (for the basal body). AP2alpha, Prox1, GAD67, Calretinin, GFAP, PKCalpha, and Chx10 antibodies as well as Brn3b-promoted tdTomato expression were used to visualize retinal cell types.Results: A group of ciliated cells were present in the inner aspects of retinal organoids from day 44 to day 266 in culture. Ciliated Chx10-positive retinal progenitor cells, GFAP-positive astrocytes, and PKCalpha-positive rod-bipolar cells were detected later during development (day 176 to day 266). Ciliation persisted during all stages of retinal developmental in AP2alpha-positive amacrine cells, but it was decreased in Brn3b-positive retinal ganglion cells (RGCs) at later time points. Additionally, AC3-positive astrocytes significantly decreased during the later stages of organoid formation.Conclusions: Amacrine cells in retinal organoids retain cilia throughout development, whereas RGC ciliation gradually and progressively decreases with organoid maturation.

  View details for DOI 10.1155/2023/6494486

  View details for PubMedID 36684387

• Directly induced human retinal ganglion cells mimic fetal RGCs and are neuroprotective after transplantation invivo. Stem cell reports Luo, Z., Chang, K., Wu, S., Sun, C., Xia, X., Nahmou, M., Bian, M., Wen, R. R., Zhu, Y., Shah, S., Tanasa, B., Wernig, M., Goldberg, J. L. 2022

  Abstract

  Retinal ganglion cell (RGC) replacement therapy could restore vision in glaucoma and other optic neuropathies. We developed a rapid protocol for directly induced RGC (iRGC) differentiation from human stem cells, leveraging overexpression of NGN2. Neuronal morphology and neurite growth were observed within 1week of induction; characteristic RGC-specific gene expression confirmed identity. Calcium imaging demonstrated gamma-aminobutyric acid (GABA)-induced excitation characteristic of immature RGCs. Single-cell RNA sequencing showed more similarities between iRGCs and early-stage fetal human RGCs than retinal organoid-derived RGCs. Intravitreally transplanted iRGCs survived and migrated into host retinas independent of prior optic nerve trauma, but iRGCs protected host RGCs from neurodegeneration. These data demonstrate rapid iRGC generation invitro into an immature cell with high similarity to human fetal RGCs and capacity for retinal integration after transplantation and neuroprotective function after optic nerve injury. The simplicity of this system may benefit translational studies on human RGCs.

  View details for DOI 10.1016/j.stemcr.2022.10.011

  View details for PubMedID 36368332

• Understanding RGC differentiation and development in retinal organoids by scRNA-seq Luo, Z., Chang, K., Tanasa, B., Goldberg, J. L. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2022

  View details for Web of Science ID 000844437006261

• Impact of Neurofibromatosis type 1 (NF1) heterozygosity on RGC death after optic nerve injury Xia, X., Sun, C., Luo, Z., Shyamsundar, S., Russano, K., Goldberg, J. L. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2022

  View details for Web of Science ID 000844401302314

• Distribution Of Primary Cilia In hESC-Derived Retinal Organoid Jarin, T., Ning, K., Luo, Z., Kowal, T., Li, B., Hu, Y., Wu, A. Y., Goldberg, J. L., Sun, Y. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2022

  View details for Web of Science ID 000844437004144

• Carbon Nanotube Polymer Scaffolds as a Conductive Alternative for the Construction of Retinal Sheet Tissue. ACS chemical neuroscience Yang, R., Yang, S., Li, K., Luo, Z., Xian, B., Tang, J., Ye, M., Lu, S., Zhang, H., Ge, J. 2021

  Abstract

  With the great success of graphene in the biomedical field, carbon nanotubes have attracted increasing attention for different applications in ophthalmology. Here, we report a novel retinal sheet composed of carbon nanotubes (CNTs) and poly(lactic-co-glycolic acid) (PLGA) that can enhance retinal cell therapy. By tuning our CNTs to regulate the mechanical characteristics of retina sheets, we were able to improve the in vitro viability of retinal ganglion cells derived from human-induced pluripotent stem cells incorporated into CNTs. Engrafted retinal ganglion cells displayed signs of regenerating processes along the optic nerve. Compared with PLGA scaffolds, CNT-PLGA retinal sheet tissue has excellent electrical conductivity, biocompatibility, and biodegradation. This new biomaterial offers new insight into retinal injury, repair, and regeneration.

  View details for DOI 10.1021/acschemneuro.1c00242

  View details for PubMedID 34375091

• Scaffolds Facilitate Epiretinal Transplantation of hiPSC-Derived Retinal Neurons in Nonhuman Primates. Acta biomaterialia Luo, Z., Xian, B., Li, K., Li, K., Yang, R., Chen, M., Xu, C., Tang, M., Rong, H., Hu, D., Ye, M., Yang, S., Lu, S., Zhang, H., Ge, J. 2021

  Abstract

  Transplantation of stem cell-derived retinal neurons is a promising regenerative therapy for optic neuropathy. However, significant anatomic differences compromise its efficacy in large animal models. The present study describes the procedure and outcomes of human-induced pluripotent stem cell (hiPSC)-derived retinal sheet transplantation in primate models using biodegradable materials. Stem cell-derived retinal organoids were seeded on polylactic-coglycolic acid (PLGA) scaffolds and directed toward a retinal ganglion cell (RGC) fate. The seeded tissues showed active proliferation, typical neuronal morphology, and electrical excitability. The cellular scaffolds were then epiretinally transplanted onto the inner surface of rhesus monkey retinas. With sufficient graft-host contact provided by the scaffold, the transplanted tissues survived for up to 1 year without tumorigenesis. Histological examinations indicated survival, further maturation, and migration. Moreover, green fluorescent protein-labeled axonal projections toward the host optic nerve were observed. Cryopreserved organoids were also able to survive and migrate after transplantation. Our results suggest the potential efficacy of RGC replacement therapy in the repair of optic neuropathy for the restoration of visual function.

  View details for DOI 10.1016/j.actbio.2021.07.040

  View details for PubMedID 34314890

• Rapid protocol for induced retinal ganglion cell differentiation from human stem cells Luo, Z., Chang, K., Tanasa, B., Wernig, M., Goldberg, J. L. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2021

  View details for Web of Science ID 000690761600554

• Retinal organoid differentiation and transplantatio Chang, K., Luo, Z., Xia, X., Knasel, C., Goldberg, J. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2020

  View details for Web of Science ID 000554495705088

• Islet1 and Brn3 Expression Pattern Study in Human Retina and hiPSC-Derived Retinal Organoid. Stem cells international Luo, Z., Xu, C., Li, K., Xian, B., Liu, Y., Li, K., Liu, Y., Rong, H., Tang, M., Hu, D., Yang, S., Ye, M., Zhong, X., Ge, J. 2019; 2019: 8786396

  Abstract

  This study was conducted to determine the dynamic Islet1 and Brn3 (POU4F) expression pattern in the human fetal retina and human-induced pluripotent stem cell- (hiPSC-) derived retinal organoid. Human fetal eyes from 8 to 27 fetal weeks (Fwks), human adult retina, hiPSC-derived retinal organoid from 7 to 31 differentiation weeks (Dwks), and rhesus adult retina were collected for cyrosectioning. Immunofluorescence analysis showed that Islet1 was expressed in retinal ganglion cells in the fetal retina, human adult retina, and retinal organoids. Unexpectedly, after Fwk 20, Brn3 expression gradually decreased in the fetal retina. In the midstage of development, Islet1 was detected in bipolar and developing horizontal cells. As the photoreceptor developed, the Islet1-positive cone precursors gradually became Islet1-negative/S-opsin-positive cones. This study highlights the distinguishing characteristics of Islet1 dynamic expression in human fetal retina development and proposes more concerns which should be taken regarding Brn3 as a cell-identifying marker in mature primate retina.

  View details for DOI 10.1155/2019/8786396

  View details for PubMedID 31885629

• Dexamethasone Provides Effective Immunosuppression for Improved Survival of Retinal Organoids after Epiretinal Transplantation. Stem cells international Xian, B. n., Luo, Z. n., Li, K. n., Li, K. n., Tang, M. n., Yang, R. n., Lu, S. n., Zhang, H. n., Ge, J. n. 2019; 2019: 7148032

  Abstract

  We investigated the efficacy of the immunosuppressants rapamycin (RAP) and dexamethasone (DEX) in improving the survival of retinal organoids after epiretinal transplantation. We first compared the immunosuppressive abilities of DEX and RAP in activated microglia in an in vitro setting. Following this, we used immunofluorescence, real-time polymerase chain reaction, and flow cytometry to investigate the effects of DEX and RAP on cells in the retinal organoids. Retinal organoids were then seeded onto poly(lactic-co-glycolic) acid (PLGA) scaffolds and implanted into rhesus monkey eyes (including a healthy individual and three monkeys with chronic ocular hypertension (OHT) induction) and subjected to different post-operative immunosuppressant treatments; 8 weeks after the experiment, histological examinations were carried out to assess the success of the different treatments. Our in vitro experiments indicated that both DEX and RAP treatments were equally effective in suppressing microglial activity. Although both immunosuppressants altered the morphologies of cells in the retinal organoids and caused a slight decrease in the differentiation of cells into retinal ganglion cells, the organoid cells retained their capacity to grow and differentiate into retinal tissues. Our in vivo experiments indicate that the retinal organoid can survive and differentiate into retinal tissues in a healthy rhesus monkey eye without immunosuppressive treatment. However, the survival and differentiation of these organoids in OHT eyes was successful only with the DEX treatment. RAP treatment was ineffective in preventing immunological rejection, and the retinal organoid failed to survive until the end of 8 weeks. DEX is likely a promising immunosuppressant to enhance the survival of epiretinal implants.

  View details for DOI 10.1155/2019/7148032

  View details for PubMedID 31428159

  View details for PubMedCentralID PMC6683795

• BAM15 attenuates transportation-induced apoptosis in iPS-differentiated retinal tissue. Stem cell research & therapy Tang, M. n., Luo, Z. n., Wu, Y. n., Zhuang, J. n., Li, K. n., Hu, D. n., Rong, H. n., Xian, B. n., Ge, J. n. 2019; 10 (1): 64

  Abstract

  BAM15 is a novel mitochondrial protonophore uncoupler capable of protecting mammals from acute renal ischemic-reperfusion injury and cold-induced microtubule damage. The purpose of our study was to investigate the effect of BAM15 on apoptosis during 5-day transportation of human-induced pluripotent stem (hiPS)-differentiated retinal tissue.Retinal tissues of 30 days and 60 days were transported with or without BAM15 for 5 days in the laboratory or by real express. Immunofluorescence staining of apoptosis marker cleaved caspase3, proliferation marker Ki67, and neural axon marker NEFL was performed. And expression of apoptotic-related factors p53, NFkappaB, and TNF-a was detected by real-time PCR. Also, location of ganglion cells, photoreceptor cells, amacrine cells, and precursors of neuronal cell types in retinal tissue was stained by immunofluorescence after transportation. Furthermore, cell viability was assessed by CCK8 assay.Results showed transportation remarkably intensified expression of apoptotic factor cleaved caspase3, p53, NFkappaB, and TNF-a, which could be reduced by supplement of BAM15. In addition, neurons were severely injured after transportation, with axons manifesting disrupted and tortuous by staining NEFL. And the addition of BAM15 in transportation was able to protect neuronal structure and increase cell viability without affecting subtypes cells location of retinal tissue.BAM15 might be used as a protective reagent on apoptosis during transporting retinal tissues, holding great potential in research and clinical applications.

  View details for DOI 10.1186/s13287-019-1151-y

  View details for PubMedID 30795805

  View details for PubMedCentralID PMC6387563

• Alpha 1-antitrypsin inhibits microglia activation and facilitates the survival of iPSC grafts in hypertension mouse model. Cellular immunology Yang, S., Xian, B., Li, K., Luo, Z., Liu, Y., Hu, D., Ge, J. 2018; 328: 49-57

  Abstract

  This study was conducted to investigate the use of Alpha 1-antitrypsin (AAT) to inhibit microglia activation in chronic hypertension model and provide a permissive environment for stem cell transplantation. Chronic ocular hypertension of C57BL/6 mice using magnetic microbead injection was induced 3 weeks prior to iPSCs transplantation. The ocular hypertension model was assessed histologically and intraocular pressure was measured. Survival of grafted cells and microglia activation were examined by flow cytometry and immunofluorescence in AAT and PBS treated hosts. Retinal cytokines expression was also detected by real-time PCR. Chronic ocular hypertension resulted in persistent microglia activation and stem cell grafts loss. AAT treatment significantly inhibited microglia activation and facilitated the survival of transplant iPSCs 4w post transplantation compared to PBS treatment. AAT holds tremendous potential for the clinical application to control neuroinflammation factor in glaucoma and improve the stem cell replacement therapy of retinal neurodegenerative disease.

  View details for DOI 10.1016/j.cellimm.2018.03.006

  View details for PubMedID 29573789

• Establishing a Surgical Procedure for Rhesus Epiretinal Scaffold Implantation with HiPSC-Derived Retinal Progenitors. Stem cells international Luo, Z. n., Li, K. n., Li, K. n., Xian, B. n., Liu, Y. n., Yang, S. n., Xu, C. n., Fan, Z. n., Lu, S. n., Zhang, H. n., Ge, J. n. 2018; 2018: 9437041

  Abstract

  To develop an effective surgical procedure for cellular scaffold epiretinal implantation in rhesus, facilitating subsequent epiretinal stem cell transplantation.Retinal progenitors were seeded onto a poly(lactic-co-glycolic) acid (PLGA) scaffold. First, the cellular scaffolds were delivered by 18G catheter or retinal forceps into rabbit epiretinal space (n = 50). Then, the cell survival rate was evaluated by Cell Counting Kit-8 (CCK-8). Second, three methods of scaffold fixation, including adhesion after gas-liquid exchange (n = 1), tamponade by hydrogel (n = 1), and fixation by retinal tacks (n = 4), were performed in rhesus monkeys. After one month, fundus photography and SD-OCT were performed to assess the outcomes, and histological examination was performed to evaluate proliferation.The cell survival rate was significantly higher in the catheter group. Follow-up examination showed that retinal tack fixation was the only method to maintain the scaffolds attached to host retina for at least 3 weeks, which is the minimal time required for cell integration. Histological staining demonstrated slight glial fibrillary acidic protein (GFAP) accumulation in the retinal tack insertion area.The established surgical procedure offers a new insight into research of epiretinal cell replacement therapy in rhesus eyes. The successful delivery and long-term fixation provide a prerequisite for cell migration and integration.

  View details for DOI 10.1155/2018/9437041

  View details for PubMedID 29760741

  View details for PubMedCentralID PMC5924980

• An Optimized System for Effective Derivation of Three-Dimensional Retinal Tissue via Wnt Signaling Regulation. Stem cells (Dayton, Ohio) Luo, Z. n., Zhong, X. n., Li, K. n., Xie, B. n., Liu, Y. n., Ye, M. n., Li, K. n., Xu, C. n., Ge, J. n. 2018; 36 (11): 1709–22

  Abstract

  Effective derivation of three-dimensional (3D) retinal tissue from human-induced pluripotent stem cells (hiPSCs) could provide models for drug screening and facilitate patient-specific retinal cell replacement therapy. However, some hiPSC lines cannot undergo 3D self-organization and show inadequate differentiation efficiency to meet clinical demand. In this study, we developed an optimized system for derivation of 3D retinal tissue. We found that the Wnt signaling pathway antagonist Dickkopf-related protein 1 (DKK-1) rescued the inability of differentiated retinal progenitors to self-organize. By evaluating DKK-1 expression and supplying DKK-1 if necessary, retinal organoids were differentiated from six hiPSC lines, which were reprogramed from three common initiating cell types. Retinal tissues derived from the optimized system were well organized and capable of surviving for further maturation. Thus, using this system, we generated retinal tissues from various hiPSC lines with high efficiency. This novel system has many potential applications in regenerative therapy and precision medicine. Stem Cells 2018;36:1709-1722.

  View details for DOI 10.1002/stem.2890

  View details for PubMedID 29999566

• HiPSC-derived retinal ganglion cells grow dendritic arbors and functional axons on a tissue-engineered scaffold. Acta biomaterialia Li, K., Zhong, X., Yang, S., Luo, Z., Li, K., Liu, Y., Cai, S., Gu, H., Lu, S., Zhang, H., Wei, Y., Zhuang, J., Zhuo, Y., Fan, Z., Ge, J. 2017; 54: 117-127

  Abstract

  Numerous therapeutic procedures in modern medical research rely on the use of tissue engineering for the treatment of retinal diseases. However, the cell source and the transplantation method are still a limitation. Previously, it was reported that a self-organizing three-dimensional neural retina can be induced from human-induced pluripotent stem cells (hiPSCs). In this study, we disclose the generation of retinal ganglion cells (RGCs) from the neural retina and their seeding on a biodegradable poly (lactic-co-glycolic acid) (PLGA) scaffold to create an engineered RGC-scaffold biomaterial. Moreover, we explored the dendritic arbor, branching point, functional axon and action potential of the biomaterial. Finally, the cell-scaffold was transplanted into the intraocular environment of rabbits and rhesus monkeys.As a part of the mammalian central nervous system (CNS), the retinal ganglion cell (RGC) shows little regenerative capacity. With the use of medical biomaterial for cells seeding and deliver, a new domain is now emerging that uses tissue engineering therapy for retinal disease. However, previous studies utilized RGCs from rodent model, which has limitations for human disease treatment. In the present study, we generated RGCs from hiPSCs-3D neural retina and then seeded these RGCs on PLGA scaffold to create an engineered RGC-scaffold biomaterial. Moreover, we assessed the transplantation method for biomaterial in vivo. Our study provides a technique to produce the engineered human RGC-scaffold biomaterial.

  View details for DOI 10.1016/j.actbio.2017.02.032

  View details for PubMedID 28216299