Pathologic vs. protective roles of hypoxia-inducible factor 1 in RPE and photoreceptors in wet vs. dry age-related macular degeneration.

It has previously been reported that antioxidant vitamins can help reduce the risk of vision loss associated with progression to advanced age-related macular degeneration (AMD), a leading cause of visual impairment among the elderly. Nonetheless, how oxidative stress contributes to the development of choroidal neovascularization (CNV) in some AMD patients and geographic atrophy (GA) in others is poorly understood. Here, we provide evidence demonstrating that oxidative stress cooperates with hypoxia to synergistically stimulate the accumulation of hypoxia-inducible factor (HIF)-1α in the retinal pigment epithelium (RPE), resulting in increased expression of the HIF-1-dependent angiogenic mediators that promote CNV. HIF-1 inhibition blocked the expression of these angiogenic mediators and prevented CNV development in an animal model of ocular oxidative stress, demonstrating the pathological role of HIF-1 in response to oxidative stress stimulation in neovascular AMD. While human-induced pluripotent stem cell (hiPSC)-derived RPE monolayers exposed to chemical oxidants resulted in disorganization and disruption of their normal architecture, RPE cells proved remarkably resistant to oxidative stress. Conversely, equivalent doses of chemical oxidants resulted in apoptosis of hiPSC-derived retinal photoreceptors. Pharmacologic inhibition of HIF-1 in the mouse retina enhanced-while HIF-1 augmentation reduced-photoreceptor apoptosis in two mouse models for oxidative stress, consistent with a protective role for HIF-1 in photoreceptors in patients with advanced dry AMD. Collectively, these results suggest that in patients with AMD, increased expression of HIF-1α in RPE exposed to oxidative stress promotes the development of CNV, but inadequate HIF-1α expression in photoreceptors contributes to the development of GA.

Anti-angiogenic properties of microRNA-29a in preclinical ocular models.

Abnormal neovascularization is an important cause of blindness in many ocular diseases, for which the etiology and pathogenic mechanisms remain incompletely understood. Recent studies have revealed the diverse roles of noncoding RNAs in various biological processes and facilitated the research and development of the clinical application of numerous RNA drugs, including microRNAs. Here, we report the antiangiogenic activity of microRNA-29a (miR-29a) in three animal models of ocular neovascularization. The miR-29a knockout (KO) mice displayed enhanced vessel pruning, resulting in a decreased vascularized area during retinal development. In contrast, miR-29a deletion in adult mice accelerated angiogenesis in preclinical disease models, including corneal neovascularization, oxygen-induced retinopathy, and choroidal neovascularization, while the administration of agomir-29a ameliorated pathological neovascularization. Furthermore, miR-29a exerted inhibitory effects on endothelial cell proliferation, migration, and tube formation capacities. RNA sequencing analysis of retinas from miR-29a KO mice and RNA interference experiments identified platelet-derived growth factor C and several extracellular matrix genes as downstream targets of miR-29a involved in regulating ocular angiogenesis. Our data suggest that miR-29a may be a promising clinical candidate for the treatment of neovascular diseases.

Therapeutic intervention in neuroinflammation for neovascular ocular diseases through targeting the cGAS-STING-necroptosis pathway.

The microglia-mediated neuroinflammation have been shown to play a crucial role in the ocular pathological angiogenesis process, but specific immunotherapies for neovascular ocular diseases are still lacking. This study proposed that targeting GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) might be a novel immunotherapy for these angiogenesis diseases. We found a significant upregulation of CGAS and STING genes in the RNA-seq data derived from retinal tissues of the patients with proliferative diabetic retinopathy. In experimental models of ocular angiogenesis including laser-induced choroidal neovascularization (CNV) and oxygen-induced retinopathy (OIR), the cGAS-STING pathway was activated as angiogenesis progressed. Either genetic deletion or pharmacological inhibition of STING resulted in a remarkable suppression of neovascularization in both models. Furthermore, cGAS-STING signaling was specifically activated in myeloid cells, triggering the subsequent RIP1-RIP3-MLKL pathway activation and leading to necroptosis-mediated inflammation. Notably, targeted inhibition of the cGAS-STING pathway with C-176 or SN-011 could significantly suppress pathological angiogenesis in CNV and OIR. Additionally, the combination of C-176 or SN-011 with anti-VEGF therapy led to least angiogenesis, markedly enhancing the anti-angiogenic effectiveness. Together, our findings provide compelling evidence for the importance of the cGAS-STING-necroptosis axis in pathological angiogenesis, highlighting its potential as a promising immunotherapeutic target for treating neovascular ocular diseases.

Long-Acting Microparticle Formulation of Griseofulvin for Ocular Neovascularization Therapy.

Neovascular age-related macular degeneration (nAMD) is a leading cause of vision loss in older adults. nAMD is treated with biologics targeting vascular endothelial growth factor; however, many patients do not respond to the current therapy. Here, a small molecule drug, griseofulvin (GRF), is used due to its inhibitory effect on ferrochelatase, an enzyme important for choroidal neovascularization (CNV). For local and sustained delivery to the eyes, GRF is encapsulated in microparticles based on poly(lactide-co-glycolide) (PLGA), a biodegradable polymer with a track record in long-acting formulations. The GRF-loaded PLGA microparticles (GRF MPs) are designed for intravitreal application, considering constraints in size, drug loading content, and drug release kinetics. Magnesium hydroxide is co-encapsulated to enable sustained GRF release over >30 days in phosphate-buffered saline with Tween 80. Incubated in cell culture medium over 30 days, the GRF MPs and the released drug show antiangiogenic effects in retinal endothelial cells. A single intravitreal injection of MPs containing 0.18 µg GRF releases the drug over 6 weeks in vivo to inhibit the progression of laser-induced CNV in mice with no abnormality in the fundus and retina. Intravitreally administered GRF MPs prove effective in preventing CNV, providing proof-of-concept toward a novel, cost-effective nAMD therapy.

Dual anti-angiogenic and anti-inflammatory action of tRNA-Cys-5-0007 in ocular vascular disease.

BACKGROUND: Intravitreal injections of angiogenesis inhibitors have proved efficacious in the majority of patients with ocular angiogenesis. However, one-fourth of all treated patients fail to derive benefits from intravitreal injections. tRNA-derived small RNA (tsRNA) emerges as a crucial class of non-coding RNA molecules, orchestrating key roles in the progression of human diseases by modulating multiple targets. Through our prior sequencing analyses and bioinformatics predictions, tRNA-Cys-5-0007 has shown as a potential regulator of ocular angiogenesis. This study endeavors to elucidate the precise role of tRNA-Cys-5-0007 in the context of ocular angiogenesis. METHODS: Quantitative reverse transcription PCR (qRT-PCR) assays were employed to detect tRNA-Cys-5-0007expression. EdU assays, sprouting assays, transwell assays, and Matrigel assays were conducted to elucidate the involvement of tRNA-Cys-5-0007 in endothelial angiogenic effects. STZ-induced diabetic model, OIR model, and laser-induced CNV model were utilized to replicate the pivotal features of ocular vascular diseases and evaluate the influence of tRNA-Cys-5-0007 on ocular angiogenesis and inflammatory responses. Bioinformatics analysis, luciferase activity assays, RNA pull-down assays, and in vitro studies were employed to elucidate the anti-angiogenic mechanism of tRNA-Cys-5-0007. Exosomal formulation was employed to enhance the synergistic anti-angiogenic and anti-inflammatory efficacy of tRNA-Cys-5-0007. RESULTS: tRNA-Cys-5-0007 expression was down-regulated under angiogenic conditions. Conversely, tRNA-Cys-5-0007 overexpression exhibited anti-angiogenic effects in retinal endothelial cells, as evidenced by reduced proliferation, sprouting, migration, and tube formation abilities. In diabetic, laser-induced CNV, and OIR models, tRNA-Cys-5-0007 overexpression led to decreased ocular vessel leakage, inhibited angiogenesis, and reduced ocular inflammation. Mechanistically, these effects were attributed to the targeting of vascular endothelial growth factor A (VEGFA) and TGF-ß1 by tRNA-Cys-5-0007. The utilization of an exosomal formulation further potentiated the synergistic anti-angiogenic and anti-inflammatory efficacy of tRNA-Cys-5-0007. CONCLUSIONS: Concurrent targeting of tRNA-Cys-5-0007 for anti-angiogenic and anti-inflammatory therapy holds promise for enhancing the effectiveness of current anti-angiogenic therapy.

Progression of retinal choroidal neovascularization by latent human cytomegalovirus infection and immunological signaling among neonatal patients admitted to tertiary care hospital.

Choroidal neovascularization (CNV) is a serious condition that affects the retina, causing partial or complete blindness in people of different ages. While CNV is a common occurrence in various chorioretinopathies, research on its occurrence in neonates is limited. Human cytomegalovirus (HCMV) is a significant health threat to neonates, with a strong association with retinal angiogenesis. However, there has been limited investigation into HCMV-associated CNV progression. In this article, we extensively studied the expression of different inflammatory cytokines and chemokines during latent HCMV-associated retinal neovascularization. Our research found that HCMV-induced CNV progression was significantly prominent in the presence of AT2R-dependent angiogenesis (p < 0.001), whereas in the absence of HCMV, AT1R-dependent CCL-5-mediated angiogenesis was documented. We also observed significant increases in CCL-19, CCL-21 chemokine responses, followed by CCR-7 chemokine receptor activation (p < 0.001) in HCMV-induced CNV patients compared to HCMV non-induced CNV groups. Furthermore, significant changes in predictive chemokine markers of HCMV-induced CNV were positively correlated with HCMV viremia. These immunological alterations ultimately lead to the switching of NFκB canonical and noncanonical pathways, respectively, in HCMV-induced neonatal CNV and HCMV non-induced CNV. This clinical observation presents a novel hypothesis that ocular HCMV latency poses a noteworthy risk factor for the progression of retinal neovascularization through a distinctive immunological signaling pathway. The current study represents the first of its kind to report on this association, which may have significant implications for the clinical management of patients with ocular HCMV.

The landscape of angiogenesis and inflammatory factors in eyes with myopic choroidal neovascularization before and after anti-VEGF injection.

INTRODUCTION: To investigate the levels of angiogenesis and inflammatory cytokines in individuals with myopic choroidal neovascularization (mCNV) and the changes in these factors following intravitreal anti-VEGF injection. METHODS: Aqueous humor samples were gathered from eyes with mCNV, those with single macular bleeding (SMB) without mCNV in highly myopic eyes, and those with age-related cataracts. Using a multiplex bead immunoassay, we analyzed 28 angiogenesis and inflammatory factors in the aqueous humor. Furthermore, clinical data were documented for correlation analysis. RESULTS: In this study, the levels of vascular endothelial growth factor A (VEGF-A), interleukin 8 (IL-8), and fibroblast growth factors 1 (FGF-1) were significantly elevated in mCNV compared to SMB eyes (p < 0.05). Their odds ratios for mCNV occurrence were 1.05, 3.45, and 2.64, respectively. Hepatocyte growth factor (HGF) and VEGF-C were notably higher in mCNV than in cataract patients (p < 0.05), and VEGF-C correlated to the degree of myopic atrophic maculopathy (p = 0.024). Axial length exhibited a negative correlation with VEGF-A and positive correlations with VEGF-C, HGF, and MCP-1 (p < 0.01). Following anti-VEGF treatment, a reduction in VEGF-A, endothelin-1, and FGF-2 was noted in mCNV patients (p < 0.05), but MCP-1 levels increased. CONCLUSION: Our findings highlight the predominant role of angiogenesis and inflammation factors in mCNV pathogenesis. VEGF-C's correlation with axial length and atrophy suggests its involvement in the process of myopic atrophic maculopathy.

Human lens epithelial-secreted exosomes attenuate ocular angiogenesis via inhibiting microglial activation.

The lens is an avascular tissue, where epithelial cells (LECs) are the primary living cells. The role of LECs-derived exosomes (LEC-exos) is largely unknown. In our study, we determined the anti-angiogenic role of LEC-exos, manifested as regressed retinal neovascularization (NV) using the oxygen-induced retinopathy (OIR), and reduced choroidal NV size and pathological vascular leakage using the laser-induced choroidal neovascularization (laser-induced CNV). Furthermore, the activation and accumulation of microglia were also restricted by LEC-exos. Based on Luminex multiplex assays, the expressions of chemokines such as SCYB16/CXCL16, MCP-1/CCL2, I-TAC/CXCL11, and MIP 3beta/CCL19 were decreased after treatment with LEC-exos. Transwell assays showed that LEC-exos restricted the migration of the mouse microglia cell line (BV2 cells). After incubation with LEC-exos-treated BV2 cells, human umbilical vein endothelial cells (hUVECs) were collected for further evaluation using tube formation, Transwell assays, and 5-ethynyl-2'-deoxyuridine (EDU) assays. Using in vitro experiments, the pro-angiogenic effect of microglia was restricted by LEC-exos. Hence, it was investigated that LEC-exos attenuated ocular NV, which might attribute to the inhibition of microglial activation and accumulation.

Verteporfin regulates corneal neovascularization through inhibition of YAP protein activation.

Corneal neovascularization (CNV) is a vision-threatening disease that is becoming a growing public health concern. While Yes-associated protein (YAP) plays a critical role in neovascular disease and allow for the sprouting angiogenesis. Verteporfin (VP) is a classical inhibitor of the YAP-TEAD complex, which is used for clinical treatment of neovascular macular degeneration through photodynamic therapy. The purpose of this study is to explore the effect of verteporfin (VP) on the inhibition of CNV and its potential mechanism. Rat CNV model were established by suturing in the central cornea and randomly divided into three groups (control, CNV and VP group). Neovascularization was observed by slit lamp to extend along the corneal limbus to the suture line. RNA-sequencing was used to reveal the related pathways on the CNV and the results revealed the vasculature development process and genes related with angiogenesis in CNV. In CNV group, we detected the nuclear translocation of YAP and the expression of CD31 in corneal neovascular endothelial cells through immunofluorescence. After the application of VP, the proliferation, migration and the tube formation of HUVECs were significantly inhibited. Furthermore, VP showed the CNV inhibition by tail vein injection without photoactivation. Then we found that the expression of phosphorylated YAP significantly decreased, and its downstream target protein connective tissue growth factor (CTGF) increased in the CNV group, while the expression was just opposite in other groups. Besides, both the expression of vascular endothelial growth factor receptor 2 (VEGFR2) and cofilin significantly increased in CNV group, and decreased after VP treatment. Therefore, we conclude that Verteporfin could significantly inhibited the CNV without photoactivation by regulating the activation of YAP.

Effects of slit lamp-delivered retinal laser photobiomodulation in a rat model of choroidal neovascularization.

Neovascular age-related macular degeneration, also known as exudative or wet age-related macular degeneration, is the leading cause of blindness in the developed world. Photobiomodulation has the potential to target the up-stream hypoxic and pro-inflammatory drivers of choroidal neovascularization. This study investigated whether photobiomodulation attenuates characteristic pathological features of choroidal neovascularization in a rodent model. Experimental choroidal neovascularization was induced in Brown Norway rats with laser photocoagulation. A custom-designed, slit-lamp-mounted, 670 nm laser was used to administer retinal photobiomodulation every 3 days, beginning 6 days prior to choroidal neovascularization induction and continuing until the animals were killed 14 days later. The effect of photobiomodulation on the size of choroidal neovascular membranes was determined using isolectin-B4 immunohistochemistry and spectral domain-optical coherence tomography. Vascular leakage was determined with fluorescein angiography. The effect of treatment on levels of vascular endothelial growth factor expression was quantified with enzyme-linked immunosorbent assay. Treatment with photobiomodulation was associated with choroidal neovascular membranes that were smaller, had less fluorescein leakage, and a diminished presence of inflammatory cells as compared to sham eyes. These effects were not associated with a statistically significant difference in the level of vascular endothelial growth factor when compared to sham eyes. The data shown herein indicate that photobiomodulation attenuates pathological features of choroidal neovascularization in a rodent model by mechanisms that may be independent of vascular endothelial growth factor.

Crocetin inhibits choroidal neovascularization in both in vitro and in vivo models.

Choroidal neovascularization (CNV) is the primary pathogenic process underlying wet age-related macular degeneration, leading to severe vision loss. Despite current anti-vascular endothelial growth factor (VEGF) therapies, several limitations persist. Crocetin, a major bioactive constituent of saffron, exhibits multiple pharmacological activities, yet its role and mechanism in CNV remain unclear. Here, we investigated the potential effects of crocetin on CNV using in vitro and in vivo models. In human umbilical vein endothelial cells, crocetin demonstrated inhibition of VEGF-induced cell proliferation, migration, and tube formation in vitro, as assessed by CCK-8 and EdU assays, transwell and scratch assays, and tube formation analysis. Additionally, crocetin suppressed choroidal sprouting in ex vivo experiments. In the human retinal pigment epithelium (RPE) cell line ARPE-19, crocetin attenuated cobalt chloride-induced hypoxic cell injury, as evidenced by CCK-8 assay. As evaluated by quantitative PCR and Western blot assay, it also reduced hypoxia-induced expression of VEGF and hypoxia-inducible factor 1α (HIF-1α), while enhancing zonula occludens-1 expression. In a laser-induced CNV mouse model, intravitreal administration of crocetin significantly reduced CNV size and suppressed elevated expressions of VEGF, HIF-1α, TNFα, IL-1ß, and IL-6. Moreover, crocetin treatment attenuated the elevation of phospho-S6 in laser-induced CNV and hypoxia-induced RPE cells, suggesting its potential anti-angiogenic effects through antagonizing the mechanistic target of rapamycin complex 1 (mTORC1) signaling. Our findings indicate that crocetin may hold promise as an effective drug for the prevention and treatment of CNV.

Single-cell profiling transcriptomic reveals cellular heterogeneity and cellular crosstalk in choroidal neovascularization model.

Choroidal neovascularization (CNV) is a hallmark of neovascular age-related macular degeneration (nAMD) and a major contributor to vision loss in nAMD cases. However, the identification of specific cell types associated with nAMD remains challenging. Herein, we performed single-cell sequencing to comprehensively explore the cellular diversity and understand the foundational components of the retinal pigment epithelium (RPE)/choroid complex. We unveiled 10 distinct cell types within the RPE/choroid complex. Notably, we observed significant heterogeneity within endothelial cells (ECs), fibroblasts, and macrophages, underscoring the intricate nature of the cellular composition in the RPE/choroid complex. Within the EC category, four distinct clusters were identified and EC cluster 0 was tightly associated with choroidal neovascularization. We identified five clusters of fibroblasts actively involved in the pathogenesis of nAMD, influencing fibrotic responses, angiogenic effects, and photoreceptor function. Additionally, three clusters of macrophages were identified, suggesting their potential roles in regulating the progression of nAMD through immunomodulation and inflammation regulation. Through CellChat analysis, we constructed a complex cell-cell communication network, revealing the role of EC clusters in interacting with fibroblasts and macrophages in the context of nAMD. These interactions were found to govern angiogenic effects, fibrotic responses, and inflammatory processes. In summary, this study reveals noteworthy cellular heterogeneity in the RPE/choroid complex and provides valuable insights into the pathogenesis of CNV. These findings will open up potential avenues for deep understanding and targeted therapeutic interventions in nAMD.

BCL6B Contributes to Ocular Vascular Diseases via Notch Signal Silencing.

BACKGROUND: Endothelial cell activation is tightly controlled by the balance between VEGF (vascular endothelial cell growth factor) and Notch signaling pathway. VEGF destabilizes blood vessels and promotes neovascularization, which are common features of sight-threatening ocular vascular disorders. Here, we show that BCL6B (B-cell CLL/lymphoma 6 member B protein), also known as BAZF, ZBTB28, and ZNF62, plays a pivotal role in the development of retinal edema and neovascularization. METHODS: The pathophysiological physiological role of BCL6B was investigated in cellular and animal models mimicking 2 pathological conditions: retinal vein occlusion and choroidal neovascularization. An in vitro experimental system was used in which human retinal microvascular endothelial cells were supplemented with VEGF. Choroidal neovascularization cynomolgus monkey model was generated to investigate the involvement of BCL6B in the pathogenesis. Mice lacking BCL6B or treated with BCL6B-targeting small-interfering ribose nucleic acid were examined for histological and molecular phenotypes. RESULTS: In retinal endothelial cells, the BCL6B expression level was increased by VEGF. BCL6B-deficient endothelial cells showed Notch signal activation and attenuated cord formation via blockage of the VEGF-VEGFR2 signaling pathway. Optical coherence tomography images showed that choroidal neovascularization lesions were decreased by BCL6B-targeting small-interfering ribose nucleic acid. Although BCL6B mRNA expression was significantly increased in the retina, BCL6B-targeting small-interfering ribose nucleic acid suppressed ocular edema in the neuroretina. The increase in proangiogenic cytokines and breakdown of the inner blood-retinal barrier were abrogated in BCL6B knockout (KO) mice via Notch transcriptional activation by CBF1 (C promotor-binding factor 1) and its activator, the NICD (notch intracellular domain). Immunostaining showed that Müller cell activation, a source of VEGF, was diminished in BCL6B-KO retinas. CONCLUSIONS: These data indicate that BCL6B may be a novel therapeutic target for ocular vascular diseases characterized by ocular neovascularization and edema.

Novel CCR3-targeted cyclic peptides as potential therapeutic agents for age-related macular degeneration via inhibiting angiogenesis and reducing retinal photoreceptor damage.

The prolonged intravitreal administration of anti-vascular endothelial growth factor (VEGF) drugs is prone to inducing aberrant retinal vascular development and causing damage to retinal neurons. Hence, we have taken an alternative approach by designing and synthesizing a series of cyclic peptides targeting CC motif chemokine receptor 3 (CCR3). Based on the binding mode of the N-terminal region in CCR3 protein to CCL11, we used computer-aided identification of key amino acid sequence, conformational restriction through different cyclization methods, designed and synthesized a series of target cyclic peptides, and screened the preferred compound IB-2 through affinity. IB-2 exhibits excellent anti-angiogenic activity in HRECs. The apoptosis level of 661W cells demonstrated a significant decrease with the escalating concentration of IB-2. This suggests that IB-2 may have a protective effect on photoreceptor cells. In vivo experiments have shown that IB-2 significantly reduces retinal vascular leakage and choroidal neovascularization (CNV) area in a laser-induced mouse model of CNV. These findings indicate the potential of IB-2 as a safe and effective therapeutic agent for AMD, warranting further development.

Lycopene inhibits endothelial-to-mesenchymal transition of choroidal vascular endothelial cells in laser-induced mouse choroidal neovascularization.

Choroidal neovascularization (CNV), is a major cause of irreversible blindness among the elderly population in developed countries, which is resulted from subretinal fibrosis without effective therapeutic strategies. Endothelial-to-mesenchymal transition (EndMT) of choroidal vascular endothelial cells (CVECs) contributes to subretinal fibrosis. Lycopene (LYC), a non-pro-vitamin A carotenoid, plays an anti-fibrotic role. Herein, we explored the effect and mechanism of LYC on the EndMT of CVECs during CNV. Firstly, LYC inhibited EndMT in hypoxic human choroidal endothelial cells (HCVECs). Meanwhile, LYC inhibited proliferation, androgen receptor (AR) expression and nuclear localization in hypoxic HCVECs. Then LYC-inhibited AR promotes the activation of microphthalmia-associated transcription factor (MITF) in hypoxic HCVECs. In addition, LYC down-regulated AR and induced MITF up-regulated pigment epithelium-derived factor (PEDF) transcription and expression in hypoxic HCVECs. Moreover, LYC-induced PEDF bound to laminin receptor (LR), inhibiting EndMT of hypoxic HCVECs via down-regulating protein kinase B (AKT)/ß-catenin pathway. In vivo, LYC alleviated mouse laser-induced subretinal fibrosis secondary to CNV via up-regulating PEDF without any ocular or systemic toxicity. These results indicate that LYC inhibits EndMT of CVECs via modulating AR/MITF/PEDF/LR/AKT/ß-catenin pathway, showing LYC is a promising therapeutic agent for CNV.

Insights into myopic choroidal neovascularization based on quantitative proteomics analysis of the aqueous humor.

BACKGROUND: Previous studies on the biomarkers of pathologic myopia choroidal neovascularization (pmCNV) development merely detected limited types of proteins and provide a meagre illustration of the underlying pathways. Hence, a landscape of protein changes in the aqueous humor (AH) of pmCNV patients is lacking. Here, to explore the potential mechanisms and biomarkers of pmCNV, we analyzed the clinical data and protein profile among atrophic (A) lesions, tractional lesions (T) and neovascular (N) lesions in myopic patients based on the ATN grading system for myopic maculopathy (MM). RESULTS: After investigating demographic data of our patients, a correlation was found between A and N lesions (R = 0.5753, P < 0.0001). Accordingly, groups were divided into patients without MM, patients with myopic atrophic maculopathy (MAM), and patients with pmCNV (N2a lesion). In proteomics analysis, the increased protein level of GFAP and complement-associated molecules in AH samples of the 3 groups also indicated that MAM and pmCNV shared similar characteristics. The GO enrichment and KEGG pathway analysis were performed, which mapped that differential expressed proteins mainly engaged in JAK-STAT pathway between the pmCNV group and two controls. Furthermore, we identified several potential biomarkers for pmCNV, including FCN3, GFAP, EGFR, SFRP3, PPP2R1A, SLIT2, and CD248. CONCLUSIONS: Atrophic lesions under pathologic myopic conditions demonstrated similarities to neovascularization development. Potential biomarkers including GFAP were associated with the pathogenesis of pmCNV. In summary, our study provides new insights for further research on pmCNV development.

Granzyme B Contributes to Choroidal Neovascularization and Age-Related Macular Degeneration Through Proteolysis of Thrombospondin-1.

Age-related macular degeneration (AMD) is a leading cause of irreversible central vision loss in the elderly. The pathology of neovascular age-related macular degeneration (nAMD), also known as wet AMD, is associated with an abnormal blood vessel growth in the eye and involves an imbalance of proangiogenic and antiangiogenic factors. Thrombospondin (TSP)-1 and TSP-2 are endogenous matricellular proteins that inhibit angiogenesis. TSP-1 is significantly diminished in eyes with AMD, although the mechanisms involved in its reduction are unknown. Granzyme B (GzmB) is a serine protease with an increased extracellular activity in the outer retina and choroid of human eyes with nAMD-related choroidal neovascularization (CNV). This study investigated whether TSP-1 and TSP-2 are GzmB substrates using in silico and cell-free cleavage assays and explored the relationship between GzmB and TSP-1 in human eyes with nAMD-related CNV and the effect of GzmB on TSP-1 in retinal pigment epithelial culture and an explant choroid sprouting assay (CSA). In this study, TSP-1 and TSP-2 were identified as GzmB substrates. Cell-free cleavage assays substantiated the GzmB proteolysis of TSP-1 and TSP-2 by showing dose-dependent and time-dependent cleavage products. TSP-1 and TSP-2 proteolysis were hindered by the inhibition of GzmB. In the retinal pigment epithelium and choroid of human eyes with CNV, we observed a significant inverse correlation between TSP-1 and GzmB, as indicated by lower TSP-1 and higher GzmB immunoreactivity. In CSA, the vascular sprouting area increased significantly with GzmB treatment and reduced significantly with TSP-1 treatment. Western blot showed significantly reduced expression of TSP-1 in GzmB-treated retinal pigment epithelial cell culture and CSA supernatant compared with that in controls. Together, our findings suggest that the proteolysis of antiangiogenic factors such as TSP-1 by extracellular GzmB might represent a mechanism through which GzmB may contribute to nAMD-related CNV. Future studies are needed to investigate whether pharmacologic inhibition of extracellular GzmB can mitigate nAMD-related CNV by preserving intact TSP-1.

Engineered Knockout of TRPA1 Inhibits Laser-Induced Choroidal Neovascularization Along With Associated TGFß1 Expression and Neutrophil Infiltration.

We examined the effects of gene ablation and chemical inhibition of transient receptor potential ankyrin 1 (TRPA1) on the growth of experimental argon laser-induced choroidal neovascularization (CNV) in mice. CNV was induced in the eyes of 6- to 8-week-old TRPA1-null (knockout [KO]) and wild-type (WT) mice by argon laser irradiation. Gene expression analysis was performed in laser-injured tissues at days 1 and 3. CNV growth was evaluated at day 14. Reciprocal bone marrow transplantation was performed between each genotype to identify the components responsible for either recipient tissue or bone marrow-derived inflammatory cells. Our results show that laser irradiation successfully induced CNV growth at the site of laser injury. The size of induced CNV was significantly smaller in KO mice than in WT mice at day 14, as determined by angiography with fluorescein isothiocyanate-dextran. Invasion of neutrophils, but not macrophages, was suppressed in association with suppression of the expression of transforming growth factor ß1 and interleukin 6 in laser-irradiated KO tissue. Bone marrow transplantation indicated that the genotype of the recipient mouse, but not of inflammatory cells, is attributable to the KO phenotype. Systemic administration of a TRPA1 antagonist also reduced the CNV in a WT mouse. In conclusion, TRPA1 signaling in local cells is involved in growth of laser-induced CNV. The phenotype was not attributable to vascular endothelial cells and inflammatory cells. Blocking TRPA1 signal may therefore be a potential treatment strategy for CNV-related ocular diseases.

5α-Hydroxycostic acid inhibits choroidal neovascularization in rats through a dual signalling pathway mediated by VEGF and angiopoietin 2.

BACKGROUND: 5α-Hydroxycostic acid is a eudemane sesquiterpene that is isolated from the natural plant, Laggera alata. It exerts anti-inflammatory and anti-angiogenic effects on human breast cancer cells, but its role and underlying mechanism in choroidal neovascularization (CNV) are still unclear. We conducted a study to verify that 5α-Hydroxycostic acid can inhibit the formation and leakage of CNV, and describe the possible dual pathway by which it exerts its inhibitory effects in this process. METHODS: An in vitro model of choroidal neovascularization was established using VEGF164, while a rat model of choroidal neovascularization was established using a 532 nm laser. In both models, the effects of 5α-Hydroxycostic acid in vivo and in vitro were evaluated to determine its inhibitory effect on abnormal cell proliferation, migration and tubule formation, as well as its effect on pathological changes in choroidal tissues and the area of neovascularization leakage in rats. The levels of components in the VEGF/VEGFR and Ang2/Tie2 signaling pathways were measured in tissues and cells. RESULTS: In vitro experiments have shown that 5α-Hydroxycostic acid can inhibit abnormal cell proliferation, migration and angiogenesis. Additionally, 5α-Hydroxycostic acid enhances cell adhesion by inhibiting the phosphorylation pathways of VEGFR2 and Tie2. In vivo experiments demonstrated that 5α-Hydroxycostic acid has a positive therapeutic effect on choroidal neovascularization in rats. It can effectively reduce vascular leakage, consistent with the results of the cell experiments. CONCLUSION: 5α-Hydroxycostic acid can inhibit choroidal neovascularization by interfering with the VEGF- and Ang2/Tie2-related pathways, and it may be a good candidate drug for treating CNV.

Old age promotes retinal fibrosis in choroidal neovascularization through circulating fibrocytes and profibrotic macrophages.

BACKGROUND: Retinal fibrosis affects 40-70% of neovascular age-related macular degeneration patients. This study investigated the effect of ageing on subretinal fibrosis secondary to choroidal neovascularization and the mechanism of action. METHODS: Subretinal fibrosis was induced in young (2.5-month) and aged (15-16-month) C57BL/6J mice using the two-stage laser protocol. Five and 30 days later, eyes were collected and stained for CD45 and collagen-1 and observed by confocal microscopy. Fibrocytes (CD45+collagen-1+) were detected in the bone marrow (BM), blood and fibrotic lesions by flow cytometry and confocal microscopy, respectively. BM-derived macrophages (BMDMs) were cultured from young and aged mice with or without TGF-ß1 (10 ng/mL) treatment. The expression of mesenchymal marker αSMA (Acta2), fibronectin (Fn1) and collagen-1 (Col1a1) was examined by qPCR and immunocytochemistry, whereas cytokine/chemokine production was measured using the Luminex multiplex cytokine assay. BM were transplanted from 22-month (Ly5.2) aged mice into 2.5-month (Ly5.1) young mice and vice versa. Six weeks later, subretinal fibrosis was induced in recipient mice and eyes were collected for evaluation of fibrotic lesion size. RESULTS: Under normal conditions, the number of circulating fibrocytes (CD45+collagen-1+) and the expression levels of Tgfb1, Col1a1, Acta2 and Fn1 in BMDMs were significantly higher in aged mice compared to young mice. Induction of subretinal fibrosis significantly increased the number of circulating fibrocytes, enhanced the expression of Col1a1, Acta2 and Fn1 and the production of soluble urokinase plasminogen activator surface receptor (suPAR) but decreased the production of CXCL10 in BMDMs. BMDMs from aged subretinal fibrosis mice produced significantly higher levels of VEGF, angiopoietin-2 and osteopontin than cells from young subretinal fibrosis mice. The subretinal fibrotic lesion in 15-16-month aged mice was 62% larger than that in 2.5-month young mice. The lesion in aged mice contained a significantly higher number of fibrocytes compared to that in young mice. The number of circulating fibrocytes positively correlated with the size of subretinal fibrotic lesion. Transplantation of BM from aged mice significantly increased subretinal fibrosis in young mice. CONCLUSIONS: A retina-BM-blood-retina pathway of fibrocyte/macrophage recruitment exists during retinal injury. Ageing promotes subretinal fibrosis through higher numbers of circulating fibrocytes and profibrotic potential of BM-derived macrophages.