A therapeutic dose-response relationship linking NT-501–derived CNTF levels to JAK/STAT3 activation and photoreceptor protection in human retinal tissue is established, and an optimal concentration range for efficacy is suggested.
Abstract
Sustained trophic factor delivery via Encapsulated Cell Technology (ECT) is a powerful new class of therapeutics with broad potential for targeted treatment. Intravitreal delivery of ciliary neurotrophic factor (CNTF) via the ECT, NT-501, is a first-in-class therapy that slows the progression of macular telangiectasia type 2 (MacTel). Despite its clinical efficacy, key questions remain regarding its mechanism of action, including whether other implant-derived factors contribute to therapeutic benefit and how optimal dosing should be determined. Resolving these issues is critical for optimizing NT-501 in MacTel and guiding the development of ECT-based therapies for other diseases. We evaluated the biological activity of implant-derived cytokines on retinal tissue, using long-term NT-501 intravitreal implants in rabbits alongside human retinal organoid (hRO) models treated with NT-501–conditioned medium (NT-501–CM). Then, using a MacTel-specific photoreceptor degeneration model in hROs, we showed NT-501–CM significantly reduced photoreceptor cell death, and this protective effect was abolished by either CNTF-neutralizing antibodies or JAK inhibitor. We also established a therapeutic dose-response relationship linking NT-501–derived CNTF levels to JAK/STAT3 activation and photoreceptor protection. These findings directly connect ECT-derived CNTF exposure with JAK/STAT3-mediated photoreceptor protection in human retinal tissue and suggest an optimal concentration range for efficacy.
Neurotrophic keratopathy (NK) is a serious ocular surface disease that develops due to a reduction or loss of corneal innervation. Conventional therapeutic approaches, such as the use of artificial tears and autologous serum, primarily serve as symptomatic relief measures and do not target the underlying neurodegenerative process. The introduction of recombinant human nerve growth factor (rhNGF, cenegermin) has marked the first disease-modifying pharmacological therapy for NK, providing evidence of enhanced epithelial healing and improved corneal sensitivity. In recent years, with biotechnological advancements and the emergence of genetic therapy strategies, the importance of pathophysiology-oriented treatments in NK therapy has increased. The objective of this review is to offer an analysis of the management of NK in the context of recent pharmacological and biotechnological advancements in the light of current literature. This review aims to provide an integrated and pathophysiology-oriented synthesis of NK management, uniquely bridging pharmacological treatments with emerging biotechnological strategies including gene therapy, cell-based approaches, and novel drug delivery systems.
M. Çiftçi, M. Gurdal, O. B. Selver· Indian Journal of Ophthalmol...· 0 citations
Purpose This study aimed to compare the neuroprotective effects of subretinally delivered human central nervous system stem cells (HuCNS-SC) and a novel, single-cell suspension formulation, Neubright (NB) in the RCS rat. Methods At postnatal day 21, RCS rats were subretinally injected with a 150,000 cell dose of either HuCNS-SC or NB in a 2 μL volume. The contralateral control eye was injected with balanced salt solution. Visual function outcomes were measured using optokinetic tracking and electroretinography. Whole globes were harvested at P60 and P180 for immunofluorescence (IF). To identify cells in the subretinal space, retinal cross-sections were stained with a human specific marker (STEM121). Cell spread, outer nuclear layer (ONL) thickness, and cell migration were quantified using confocal microscopy and image J. Results IF demonstrated a clear presence of STEM121-positive cells in the subretinal space after delivery of both HuCNS-SC and NB. The ONL was thicker in areas adjacent to the injected cells, whereas a greater degree of degeneration was observed outside of treated areas. The novel NB formulation had significantly increased cell spread and visual performance compared to the original HuCNS-SC formulation. Conclusions A novel single-cell suspension of human neural stem cells, NB, with high cell viability was successfully generated. NB improved cell spread in the subretinal space compared to HuCNS-SC improving visual outcomes in the RCS rat. Translational Relevance: This bridging study will be used as an investigational new drug approval enabling study to evaluate NB in clinical trials for macular retinal degeneration.
Sebastian Arrizabalaga, N. Uchida, Allison G Curtis et al.· PLoS ONE· 0 citations
BACKGROUND
Parkinson's disease (PD) is a neurodegenerative disorder marked by motor dysfunction. No definitive methods exist to repair damaged neurons. Vascular endothelial growth factor (VEGF) and nerve growth factor (NGF) are two neuroprotective agents that work synergistically. However, these large molecular proteins have difficulty crossing the blood-brain barrier (BBB). Extracellular vesicles (EVs) offer superior targeting and low immunogenicity, making them excellent carriers. In this study we examined the protective effects of VEGF and NGF in a cell model and evaluated the therapeutic potential of VEGF-NGF contained within EVs in PD rats.
METHODS
EVs were isolated using sequential differential centrifugation and characterized using transmission electron microscopy, nanoparticle tracking analysis, and western blotting (WB). VEGF and NGF were loaded into the EVs using a saponin-assisted method to create VEGF@EVs, NGF@EVs, and VEGF/NGF@EVs. The viability of 6-hydroxydopamine hydrochloride (6-OHDA)-induced SH-SY5Y cells was measured using the cell counting kit-8 assay before and after treatment with VEGF and NGF. Autophagy levels were assessed using WB, and the role of autophagy was further explored using the autophagy inhibitor chloroquine. Unilateral PD rat models were established via stereotactic injection of 6-OHDA into male Sprague-Dawley rats. Behavioral changes were monitored before and after treatment. Neuronal recovery, neurotransmitter levels, and autophagy levels in the rat brains were evaluated using immunohistochemistry, enzyme-linked immunosorbent assay, and WB.
RESULTS
VEGF/NGF@EVs significantly enhanced the viability of 6-OHDA-induced SH-SY5Y cells. A complete autophagic process was identified as essential for this protective effect. The intranasal administration of VEGF/NGF@EVs improved motor behavior in PD rats, with performance better than that of single growth factor treatments. The number of tyrosine hydroxylase (TH)-positive neurons, TH protein expression, and dopamine content were significantly increased. In addition, the level of autophagy in the rat substantia nigra was elevated.
CONCLUSIONS
VEGF/NGF@EVs exert protective effects in both in vitro and in vivo 6-OHDA-induced PD models by promoting autophagy, demonstrating greater efficacy than either growth factor alone. By transplanting VEGF/NGF@EVs into PD rats, we showed that these vesicles can effectively cross the BBB and deliver targeted therapy to the central nervous system. This study highlights the significant potential of EV-mediated protein transplantation strategies for treating neurological disorders.
Wenyu Yan, Xianyue Meng, Yan Wang et al.· Journal of Integrative Neuro...· 0 citations
Dry age-related macular degeneration (dAMD) is a leading cause of irreversible vision loss, driven by chronic oxidative stress and inflammation in the retinal pigment epithelium (RPE). Disruption of key negative regulators of the JAK-STAT pathway, particularly SOCS3, contributes to this oxidative-inflammatory cascade. To address this, we developed a dual-restricted ocular gene delivery platform that combines suprachoroidal administration with an RPE-specific Best1 promoter, enabling localized, durable, and cell-restricted SOCS3 expression. Comparative analysis showed that intravitreal injection poorly transduced the RPE, whereas suprachoroidal delivery improved AAV access to the RPE/outer retinal region, and the Best1 promoter further restricted expression to RPE cells, reducing neural retinal off-target expression. In vitro, SOCS3 restoration suppressed STAT3 activation, inflammatory cytokine release, reactive oxygen species accumulation, mitochondrial disruption, and barrier impairment. In vivo, the dual-restricted system achieved long-term, ocular-localized expression for at least six months, reducing microglial/macrophage activation, inflammation, oxidative stress, and apoptosis, thereby preserving outer retinal architecture. Ocular and systemic safety assessments detected no overt toxicity under the tested conditions. Together, these findings support suprachoroidal AAV-Best1-SOCS3 delivery as a dual-restricted platform for localized modulation of oxidative-inflammatory retinal degeneration and warrant further preclinical evaluation.
Yiquan Zhang, F. Luan, Jing Feng et al.· Journal of Controlled Releas...· 0 citations
Abstract Retinal degenerations, comprising a heterogeneous group of disorders culminating in neuroretinal dysfunction, such as inherited retinal dystrophies (IRDs) and age-related retinal degeneration, are among the leading causes of irreversible vision loss worldwide. Restoring visual function through cell replacement therapy represents an attractive, yet challenging, strategy. Candidate retinal cell sources include retinal progenitor cells (RPCs), Müller glia, human neuroretinal stem-like cells (hNRSCs), and pluripotent stem cells (PSCs). In this review, we discuss their translational advantages and limitations, which in turn influence clinical implementation. We analyze critical manufacturing challenges, including GMP scalability, quality assurance, and ethical considerations in donor material sourcing. Experimental criteria for assessing cellular products’ integration into host circuitry and their capacity to restore visual function in preclinical retinal degeneration models must account for donor maturity, host retina architecture, and immune modulation, which determine survival, synapse connectivity, and delivery requirements. Ongoing clinical trials highlight the diversity of cell replacement strategies—from fetal-derived and allogenic progenitor suspensions to laminated PSC-derived retinal sheets—with each approach presenting distinct implications for survival, true integration, and logistical complexity.
S. Saietz, Filippo Locri, Helena Isla-Magrané et al.· Stem Cells Translational Med...· 0 citations
Wet age-related macular degeneration (wAMD) is a leading cause of irreversible vision loss characterized by pathological choroidal neovascularization (CNV). While anti-VEGF therapies are the standard of care, limitations such as treatment resistance and side effects necessitate novel therapeutic agents. This study evaluates the therapeutic efficacy and mechanism of EV30, a novel pterostilbene derivative, in suppressing CNV. EV30 was synthesized based on the pterostilbene template. In vitro, the effects of EV30 on human umbilical vein endothelial cells (HUVECs) proliferation, migration, and tube formation were assessed using Cell Counting Kit-8 (CCK-8), scratch wound, and tube formation assays, respectively. Mechanistic pathways were investigated via Western blotting and RT-qPCR. In vivo, a laser-induced CNV mouse model was treated with intravitreal EV30. Efficacy was evaluated utilizing fundus photography, fluorescein angiography (FFA), optical coherence tomography (OCT), and choroidal flat mounts (IB4 staining). Finally, biosafety was assessed through histology (H&E), electroretinography (ERG), and blood analysis. EV30 demonstrated potent anti-angiogenic properties in vitro, significantly inhibiting HUVEC proliferation, migration, and tube formation in a dose- and time-dependent manner. EV30 reduced vascular endothelial growth factor A (VEGFA) expression and modulated the phosphorylation status of proteins associated with the mTOR/NF-κB/p38 MAPK signaling pathway. In the laser-induced CNV model, EV30 effectively reduced lesion area and vascular leakage comparable to bevacizumab. Furthermore, ERG analysis revealed that EV30 partially preserved retinal electrophysiological function, as indicated by improved scotopic a-wave amplitudes, suggesting functional protection of the retina in the CNV model. EV30 exerted anti-angiogenic effects and was associated with modulation of mTOR/NF-κB/p38 MAPK signaling activity. Together, these findings suggest that EV30 represents a potential therapeutic candidate for CNV by suppressing pathological angiogenesis and modulating inflammation-associated signaling pathways.
Songyu Xu, Qiao Zhuo, Jing Li et al.· Microvascular Research· 0 citations