Choroidal Neovascularization Lesions Research Articles

Two macular holes due to choroidal neovascularization after pars plana vitrectomy with internal limiting membrane peeling

Introduction: To present a case of two macular holes (MHs) with myopic choroidal neovascularization (CNV) lesion. Case Presentation: A single case was evaluated. A 72-year-old woman presented with two small MHs in her left eye. One year ago, she had undergone vitrectomy for myopic foveal schisis, and a significant reduction of the schisis and a CNV lesion was observed after surgery. On examination, OCT (optical coherence tomography) showed the atrophic CNV and two MHs were located upper and lower close to the edge of the CNV. A PPV (pars plana vitrectomy) with two free ILM (internal limiting membrane) flaps implant was performed in her left eye. At 3 months after surgery, the two macular holes were both closed and the BCVA (best corrected visual acuity) was improved. Conclusions: Two MHs secondary to the regression of CNV after primary PPV combined with complete ILM peeling in eyes with macular schisis.

Imaging-Guided Classification of Neovascularization in Neovascular Age-Related Macular Degeneration: Progress to Date.

Purpose: To review the evolution of terminology describing the classification of lesions in neovascular age-related macular degeneration (nAMD) based on retinal imaging technologies. Methods: A review of the current and historical literature on imaging-guided classification of neovascularization in nAMD was performed. Results: Imaging-guided classification of neovascularization in nAMD facilitates understanding of the pathological mechanisms and disease progression. Neovascularization classification has evolved with advances in imaging technologies, from earlier classifications based on neovascularization patterns assessed by fluorescein angiography to multimodal imaging patterns, resulting in varied descriptions of lesions depending on the techniques used. Until recently, there has been a lack of consensus regarding the clinical features of choroidal neovascularization lesion types as a result of the imaging modalities initially used to define them; a recent consensus on classification has the potential to simplify and clarify descriptions of neovascularization in nAMD. The use of multimodal imaging techniques will improve lesion identification and has the potential to individualize treatment plans and improve outcomes. Conclusions: Widespread adoption of a consensus-based, image-guided classification system for neovascular lesions in nAMD and the appropriate imaging techniques used to identify them will aid clinical research and could potentially improve patient outcomes by individualizing treatment plans in the future.

Inflammasome activation aggravates choroidal neovascularization.

Inflammasome activation is implicated in diseases of aberrant angiogenesis such as age-related macular degeneration (AMD), though its precise role in choroidal neovascularization (CNV), a characteristic pathology of advanced AMD, is ill-defined. Reports on inhibition of inflammasome constituents on CNV are variable and the precise role of inflammasome in mediating pathological angiogenesis is unclear. Historically, subretinal injection of inflammasome agonists alone has been used to investigate retinal pigmented epithelium (RPE) degeneration, while the laser photocoagulation model has been used to study pathological angiogenesis in a model of CNV. Here, we report that the simultaneous introduction of any of several disease-relevant inflammasome agonists (Alu or B2 RNA, Alu cDNA, or oligomerized amyloid β (1-40)) exacerbates laser-induced CNV. These activities were diminished or abrogated by genetic or pharmacological targeting of inflammasome signaling constituents including P2rx7, Nlrp3, caspase-1, caspase-11, and Myd88, as well as in myeloid-specific caspase-1 knockout mice. Alu RNA treatment induced inflammasome activation in macrophages within the CNV lesion, and increased accumulation of macrophages in an inflammasome-dependent manner. Finally, IL-1β neutralization prevented inflammasome agonist-induced chemotaxis, macrophage trafficking, and angiogenesis. Collectively, these observations support a model wherein inflammasome stimulation promotes and exacerbates CNV and may be a therapeutic target for diseases of angiogenesis such as neovascular AMD.

Beta-alanine promotes angiogenesis in laser-induced choroidal neovascularization mice models.

To investigate the effect of β-alanine (BA) on laser-induced choroidal neovascularization (CNV) mice models. Laser-induced CNV mice models were established, and BA was administrated for one week and two weeks in advance, separately. Furthermore, retinal pigment epithelium (RPE)-choroid flat mounts were separated, and immunohistochemical staining was performed. The laser-induced CNV lesion areas were measured and compared. In addition, liver and kidney morphologies were observed to identify potential hepatorenal toxicity. Enlarged CNV lesion areas were observed in the BA treated group. No significant differences were observed in the liver and kidney sections between groups. BA treatment increase CNV lesion areas, suggesting the detrimental effects of BA as a nutritional supplement in age-related macular degeneration (AMD) population.

The Effects of STRA6 Regulation of the Circadian Rhythm on Choroidal Neovascularization.

This study aims to investigate the relationship among STRA6, circadian rhythm, and choroidal neovascularization (CNV) formation, as well as the regulatory mechanism of STRA6 in CNV under circadian rhythm disturbances. C57BL/6J male mice (aged 6 weeks) were randomly divided into control and jet lag groups (using a time shift method every 4days to disrupt the molecular clock's capacity to synchronize with a stable rhythm). A laser-induced CNV model was established in both the control and the jet lag group after 2 weeks of jet lag. The size of CNV lesions and vascular leakage were detected by morphological and imaging examination on the seventh day post laser. STRA6 was screened by full transcriptome sequencing. Bioinformatics analysis was conducted to assess the variation and association of STRA6 in the GSE29801 dataset. The effects of STRA6 were evaluated both in vivo and in vitro. The pathway mechanism was further elucidated and confirmed through immunofluorescence of paraffin sections and Western blotting. The disturbance of circadian rhythm promotes the formation of CNV. Patients with age-related macular degeneration (AMD) exhibited higher levels of STRA6 expression compared to the control group, and STRA6 was enriched in pathways related to angiogenesis. In addition, CLOCK and BMAL1, which are initiators that drive the circadian cycle, had regulatory effects on STRA6. Knocking down STRA6 reversed the promotion of CNV formation caused by circadian rhythm disturbance in vivo, and it also affected the proliferation, migration, and VEGF secretion of RPE cells without circadian rhythm in vitro, as well as impacting endothelial cells. Through activation of the JAK2/STAT3/VEGFA signaling pathway in unsynchronized RPE cells, STRA6 promotes CNV formation. This study suggests that STRA6 reduces CNV production by inhibiting JAK2/STAT3 phosphorylation after circadian rhythm disturbance. The results suggest that STRA6 may be a new direction for the treatment of AMD.

Targeted 8-arm PEG Nanosystems for Localization of Choroidal Neovascularization Macular Degeneration Model.

8-arm PEG (polyethylene-glycol) is a highly promising nanoplatform due to its small size (<10 nm), ease-of-conjugation (many functionalized variants are readily available with "click-like" properties), biocompatibility, and optical inactivity. This study evaluates 8-arm PEG uptake into cells (in vitro) and localization and clearance in vasculature (in vivo) for targeting of choroidal neovascularization in mice, an animal model of macular degeneration. 8-arm PEG nanoparticles were labeled with fluorescein isothiocyanate (FITC) and functionalized in the absence or presence of pentameric Ar-Gly-Asp (RGD; 4 RGD motifs and a PGC linker), one of the most common peptide motifs used for active targeting. In vitro studies show that RGD-conjugated 8-arm PEG nanoparticles exhibit enhanced cellular uptake relative to non-RGD-conjugated control NPs at 34% ± 9%. Laser-induced choroidal neovascularization (CNV) was performed in a mouse model to measure 8-arm PEG localization and clearance to model macular degeneration lesions in vivo. It was determined that both RGD-conjugated and non-RGD-conjugated (nRGD) 8-arm PEG particles localized to CNV lesions, with a half-life around 24 h. In vivo experiments showed that RGD-conjugated nanoparticles exhibited enhanced localization by 15-20% relative to without RGD controls. Exhibiting a high rate of localization and fast clearance relative to larger nanoparticles, targeted 8-arm PEG nanoparticles with a conjugated RGD-peptide could be a promising modality for macular degeneration diagnosis and therapy.

Natural killer cells promote neutrophil extracellular traps and restrain macular degeneration in mice.

Neovascular age-related macular degeneration (nvAMD) is the leading cause of blindness in the elderly population. Although it is known that nvAMD is associated with focal inflammation, understanding of the precise immune components governing this process remains limited. Here, we identified natural killer (NK) cells as a prominent lymphocyte population infiltrating the perivascular space of choroidal neovascularization (CNV) lesions in patients with nvAMD and in mouse models. Olink proteomic analysis and single-cell RNA sequencing combined with knockout studies demonstrated the involvement of C-C chemokine receptor 5 (CCR5) in NK cell recruitment and extravasation at the CNV sites of mice. Depletion of NK cells or inhibition of activating receptor NK group 2, member D (NKG2D) inhibited the formation of neutrophil extracellular traps, increased vascular leakage, and exacerbated pathological angiogenesis, indicating that NK cells restrain pathogenesis in this mouse model. Age is the strongest risk factor for AMD, and we show that NK cells from aged human donors exhibited a less cytotoxic phenotype. NK cells from old mice exhibited compromised protective effects in the CNV mouse model. In addition, interleukin-2 complex-mediated expansion of NK cells improved CNV formation in mice. Collectively, our study highlights NK cells as a potential therapeutic target for patients with nvAMD.

PDK4-mediated metabolic reprogramming is a potential therapeutic target for neovascular age-related macular degeneration

Age-related macular degeneration (AMD) causes severe blindness in the elderly due to choroidal neovascularization (CNV), which results from the dysfunction of the retinal pigment epithelium (RPE). While normal RPE depends exclusively on mitochondrial oxidative phosphorylation for energy production, the inflammatory conditions associated with metabolic reprogramming of the RPE play a pivotal role in CNV. Although mitochondrial pyruvate dehydrogenase kinase (PDK) is a central node of energy metabolism, its role in the development of CNV in neovascular AMD has not been investigated. In the present study, we used a laser-induced CNV mouse model to evaluate the effects of Pdk4 gene ablation and treatment with pan-PDK or specific PDK4 inhibitors on fluorescein angiography and CNV lesion area. Among PDK isoforms, only PDK4 was upregulated in the RPE of laser-induced CNV mice, and Pdk4 gene ablation attenuated CNV. Next, we evaluated mitochondrial changes mediated by PDK1-4 inhibition using siRNA or PDK inhibitors in inflammatory cytokine mixture (ICM)-treated primary human RPE (hRPE) cells. PDK4 silencing only in ICM-treated hRPE cells restored mitochondrial respiration and reduced inflammatory cytokine secretion. Likewise, GM10395, a specific PDK4 inhibitor, restored oxidative phosphorylation and decreased ICM-induced upregulation of inflammatory cytokine secretion. In a laser-induced CNV mouse model, GM10395 significantly alleviated CNV. Taken together, we demonstrate that specific PDK4 inhibition could be a therapeutic strategy for neovascular AMD by preventing mitochondrial metabolic reprogramming in the RPE under inflammatory conditions.

H-151, a Selective STING Inhibitor, Has Potential as a Treatment for Neovascular Age-Related Macular Degeneration.

The cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS) stimulator of interferon gene (STING) pathway is a crucial cascade in the inflammatory response initiated by the recognition of cytosolic double-stranded DNA (dsDNA). The aim of this study was to evaluate the effect of STING inhibitor in murine choroidal neovascularization (CNV). To investigate whether the cGAS-STING pathway is activated during CNV, CNV was induced using laser photocoagulation in male C57BL/6J mice. The expression of change of cGAS and STING during CNV development was confirmed by Western-blotting. H-151, a potent STING palmitoylation antagonist, was used as a STING inhibitor. H-151 was administered intravitreally immediately after laser induction. To confirm the role of the cGAS-STING pathway in CNV formation, we evaluated CNV size and performed fundus fluorescein angiography. The expression levels of cGAS and STING were significantly upregulated in the RPE-choroid complex after CNV induction, and dsDNA merged with cGAS was observed in CNV lesions. Intravitreal administration of H-151 suppressed CNV development and fluorescent leakage from neovessels. In CNV lesions, the high expression of STING and cGAS was observed in infiltrating F4/80+ macrophages. H-151 administration attenuated downstream signals of the cGAS-STING pathway, including the phosphorylation of nuclear factor-κB, and downregulated the expression of interleukin 1β. These findings support that the inhibition of cGAS-STING pathway treats abnormal ocular angiogenesis.

Botulinum neurotoxin serotype A inhibited ocular angiogenesis through modulating glial activation via SOCS3.

Pathological angiogenesis causes significant vision loss in neovascular age-related macular degeneration and other retinopathies with neovascularization (NV). Neuronal/glial-vascular interactions influence the release of angiogenic and neurotrophic factors. We hypothesized that botulinum neurotoxin serotype A (BoNT/A) modulates pathological endothelial cell proliferation through glial cell activation and growth factor release. A laser-induced choroidal NV (CNV) was employed to investigate the anti-angiogenic effects of BoNT/A. Fundus fluorescence angiography, immunohistochemistry, and real-time PCR were used to assess BoNT/A efficacy in inhibiting CNV and the molecular mechanisms underlying this inhibition. Neuronal and glial suppressor of cytokine signaling 3 (SOCS3) deficient mice were used to investigate the molecular mechanisms of BoNT/A in inhibiting CNV via SOCS3. In laser-induced CNV mice with intravitreal BoNT/A treatment, CNV lesions decreased > 30%; vascular leakage and retinal glial activation were suppressed; and Socs3 mRNA expression was induced while vascular endothelial growth factor A (Vegfa) mRNA expression was suppressed. The protective effects of BoNT/A on CNV development were diminished in mice lacking neuronal/glial SOCS3. BoNT/A suppressed laser-induced CNV and glial cell activation, in part through SOCS3 induction in neuronal/glial cells. BoNT/A treatment led to a decrease of pro-angiogenic factors, including VEGFA, highlighting the potential of BoNT/A as a therapeutic intervention for pathological angiogenesis in retinopathies.

Sema4D Knockout Attenuates Choroidal Neovascularization by Inhibiting M2 Macrophage Polarization Via Regulation of the RhoA/ROCK Pathway.

The aim of this study was to elucidate the role of Sema4D in the pathogenesis of senescence-associated choroidal neovascularization (CNV) and to explore its underlying mechanisms. In this study, we utilized a model of laser-induced CNV in both young (3 months old) and old (18 months old) mice, including those with or without Sema4D knockout. The expression and localization of Sema4D in CNV were assessed using PCR, Western blot, and immunostaining. Subsequently, the morphological and imaging examinations were used to evaluate the size of CNV and vascular leakage. Finally, the expression of M2 markers, senescence-related markers, and molecules involved in the RhoA/ROCK pathway was detected. We found that Sema4D was predominantly expressed in macrophages within CNV lesions, and both the mRNA and protein levels of Sema4D progressively increased following laser photocoagulation, a trend more pronounced in old mice. Moreover, Sema4D knockout markedly inhibited M2 polarization in senescent macrophages and reduced the size and leakage of CNV, particularly in aged mice. Mechanistically, aging was found to upregulate RhoA/ROCK signaling, and knockout of Sema4D effectively suppressed the activation of this pathway, with more significant effects observed in aged mice. Our findings revealed that the deletion of Sema4D markedly inhibited M2 macrophage polarization through the suppression of the RhoA/ROCK pathway, ultimately leading to the attenuation of senescence-associated CNV. These data indicate that targeting Sema4D could offer a promising approach for gene editing therapy in patients with neovascular age-related macular degeneration.

Role of NLRP3 Inflammasomes in Monocyte and Microglial Recruitments in Choroidal Neovascularization.

Although the pathogenesis of choroidal neovascularization (CNV) is largely unknown in age-related macular degeneration (AMD), inflammasomes may contribute to CNV development and progression. To understand the role NLRP3 inflammasomes in CNV, we used Ccr2RFPCx3cr1GFP dual-reporter mice and immunostaining techniques to confirm localization of NLRP3 inflammasomes in the laser-induced CNV (LCNV) lesions. Confocal microscopy was used to image and quantify LCNV volumes. MCC950 was used as NLRP3 inhibitor. ELISA and quantitative RT-PCR were used to confirm the activation of NLRP3 by monitoring the expression of IL-1β protein and mRNA in choroidal tissues from LCNV mice. In addition, NLRP3 (-/-) LCNV mice were used to investigate whether NLRP3 inflammasomes contribute to the development of LCNV lesions. We observed that red fluorescent protein (RFP)-positive monocyte-derived macrophages and GFP-positive microglia-derived macrophages, in addition to other cell types, were localized in LCNV lesions at day 7 post-laser injury. In addition, NLRP3 inflammasomes are associated with LCNV lesions. Inhibition of NLRP3 inflammasomes, using MCC950, caused an increased Ccr2RFP-positive macrophages, Cx3cr1GFP-positive microglia, and other cells, resulting in an increase in total lesion size. NLRP3 (-/-) LCNV mice showed significantly increased lesion size compared with age-matched controls. Inhibition of NLRP3 resulted in decreased IL-1β mRNA and protein expression in the choroidal tissues, suggesting that increased lesion size may not be directly related to IL-1β.

Chorioretinal Atrophic Lesions Evolution in Patients with Quiescent Myopic Choroidal Neovascularization Followed for More Than 10 Years.

To evaluate the progression of chorioretinal atrophic areas associated with myopic choroidal neovascularization (CNV) in high myopic patients followed by a minimum period of 10 years. Patients with myopic CNV lesions that achieved clinical and structural remissions over 10 years of follow-up were included. Medical records were reviewed for CNV characterization and treatment, best-corrected visual acuity at baseline (BCVA0), immediately after the last treatment (BCVA1) and at the latest visit (BCVA2). Fundus autofluorescence (FAF) was used to quantify the amount of atrophic area increase per year associated with the treated myopic CNV lesion. The first FAF performed after treatment suspension (FAF1) was compared with the most recent exam (FAF2). Thirty-six eyes from 36 patients were included. Mean total follow-up was 12.38 ± 2.68 years. Mean number of intravitreal injections (IVI) was 12.50 ± 12.40 and 25% of the eyes had previous treatment with photodynamic therapy (PDT). Mean improvement between BCVA0 and BCVA1 was 5.58 ± 15.98 letters (p < 0.001). However, a drop of 8.03 ± 12.25 letters was noticed between BCVA1 and BCVA2. FAF1 was 6.34 ± 4.92mm2 and increased to 9.88 ± 7.56mm2 (3.54 ± 3.79mm2 variation p < 0.001). The mean growth rate of the atrophic area was 0.89 ± 0.84mm2 per year. BCVA2 negatively correlated with FAF2 (k = -0.498, p = 0.002) being worse in patients with higher atrophic area growth rate (k = -0.341, p = 0.042). Eyes treated with PDT needed less IVI (5.89 ± 5.21 vs 14.70 ± 13.36, p = 0.008) but had larger FAF1 (9.80 ± 5.33 vs 5.19 ± 4.27, p = 0.013) and FAF2 (16.05 ± 7.10 vs 7.83 ± 6.63, p = 0.003). Hypothyroidism was associated with higher atrophy growth rate (1.55 ± 1.15 vs 0.73 ± 0.67, p = 0.016). This research demonstrates the importance of chorioretinal atrophy progression after myopic CNV lesions regression and its impact on visual prognosis, reporting a mean yearly growth of 0.89 mm2 in atrophic areas. Previous treatment with PDT and hypothyroidism were identified as risk factors associated with larger atrophic areas and worse visual outcomes.

MiR-199a-5p modulates choroidal neovascularization by regulating Wnt7b/Wnt/β-catenin signaling pathway.

Choroidal neovascularization (CNV) can be seen in many fundus diseases, and lead to fundus exudation, bleeding, or vision loss. miRNAs are vital regulator in CNV. miR-199a-5p has been proved to be involved in regulating vascular formation of endothelial cells, but its role in CNV remains unclear. This study aims to study the role of miR-199a-5p in CNV. Laser irradiation was used to induce CNV model. The lesion area of CNV was calculated by high-resolution angiography with fluorescein isothiocyanate-dextran. Wnt family member 7b (Wnt7b), β-catenin, and Wnt pathway proteins was measured by western blot. Immunofluorescence was performed to test Wnt7b, β-catenin, CD31, and p-p65. miR-199a-5p and Wnt7b mRNA were tested by reverse transcription real-time polymerase chain reaction. Cell count kit-8, wound healing, Transwell, tube formation, and flow cytometry were used to detect the function of miR-199a-5p and Wnt7b on human retinal microvascular endothelial cells (HRMEC). TargetScan database and dual-luciferase reporter assay verified the interaction between miR-199a-5p and Wnt7b. The results revealed that Wnt7b increased in CNV rats. Knocking down Wnt7b repressed cell proliferation, migration, invasion, and angiogenesis, and accelerated cell apoptosis of HRMEC. Dual-luciferase reporter assay verified that miR-199a-5p targeted Wnt7b. Overexpression of miR-199a-5p inhibited the angiogenesis of HRMEC and promoted cell apoptosis by inhibiting Wbt7b. In vivo experiment found that Wnt7b rescued the promotion of miR-199a-5p inhibition on CNV lesion of rats. In addition, Wnt7b positively regulated Wnt/β-catenin signaling pathway and promoted the angiogenesis of HRMEC. In conclusion, overexpression of miR-199a-5p inhibited the angiogenesis of HRMEC by regulating Wnt7b/Wnt/β-catenin signaling pathway, which may serve as a promising therapy target of CNV.

Microglial repopulation restricts ocular inflammation and choroidal neovascularization in mice.

Age-related macular degeneration (AMD) is a prevalent, chronic and progressive retinal degenerative disease characterized by an inflammatory response mediated by activated microglia accumulating in the retina. In this study, we demonstrate the therapeutically effects and the underlying mechanisms of microglial repopulation in the laser-induced choroidal neovascularization (CNV) model of exudative AMD. The CSF1R inhibitor PLX3397 was used to establish a treatment paradigm for microglial repopulation in the retina. Neovascular leakage and neovascular area were examined by fundus fluorescein angiography (FFA) and immunostaining of whole-mount RPE-choroid-sclera complexes in CNV mice receiving PLX3397. Altered cellular senescence was measured by beta-galactosidase (SA-β-gal) activity and p16INK4a expression. The effect and mechanisms of repopulated microglia on leukocyte infiltration and the inflammatory response in CNV lesions were analyzed. We showed that ten days of the CSF1R inhibitor PLX3397 treatment followed by 11 days of drug withdrawal was sufficient to stimulate rapid repopulation of the retina with new microglia. Microglial repopulation attenuated pathological choroid neovascularization and dampened cellular senescence in CNV lesions. Repopulating microglia exhibited lower levels of activation markers, enhanced phagocytic function and produced fewer cytokines involved in the immune response, thereby ameliorating leukocyte infiltration and attenuating the inflammatory response in CNV lesions. The microglial repopulation described herein are therefore a promising strategy for restricting inflammation and choroidal neovascularization, which are important players in the pathophysiology of AMD.

Granzyme B degrades extracellular matrix and promotes inflammation and choroidal neovascularization

Age-related macular degeneration (AMD) is a common retinal neurodegenerative disease among the elderly. Neovascular AMD (nAMD), a leading cause of AMD-related blindness, involves choroidal neovascularization (CNV), which can be suppressed by anti-angiogenic treatments. However, current CNV treatments do not work in all nAMD patients. Here we investigate a novel target for AMD. Granzyme B (GzmB) is a serine protease that promotes aging, chronic inflammation and vascular permeability through the degradation of the extracellular matrix (ECM) and tight junctions. Extracellular GzmB is increased in retina pigment epithelium (RPE) and mast cells in the choroid of the healthy aging outer retina. It is further increased in donor eyes exhibiting features of nAMD and CNV. Here, we show in RPE-choroidal explant cultures that exogenous GzmB degrades the RPE-choroid ECM, promotes retinal/choroidal inflammation and angiogenesis while diminishing anti-angiogenic factor, thrombospondin-1 (TSP-1). The pharmacological inhibition of either GzmB or mast-cell degranulation significantly reduces choroidal angiogenesis. In line with our in vitro data, GzmB-deficiency reduces the extent of laser-induced CNV lesions and the age-related deterioration of electroretinogram (ERG) responses in mice. These findings suggest that targeting GzmB, a serine protease with no known endogenous inhibitors, may be a potential novel therapeutic approach to suppress CNV in nAMD.

M2-type macrophage-targeted delivery of IKKβ siRNA induces M2-to-M1 repolarization for CNV gene therapy

Choroidal Neovascularization (CNV) is capable of inciting recurrent hemorrhage in the macular region, severely impairing patients' visual acuity. During the onset of CNV, infiltrating M2 macrophages play a crucial role in promoting angiogenesis.To control this disease, our study utilizes the RNA interference (RNAi)-based gene therapy to reprogram M2 macrophages to the M1 phenotype in CNV lesions. We synthesize the mannose-modified siRNA-loaded liposome specifically targeting M2 macrophages to inhibit the inhibitory kappa B kinase β (IKKβ) gene involved in the polarization of macrophages, consequently modulating macrophage polarization state. In vitro and in vivo, the mannose-modified IKKβ siRNA-loaded liposome (siIKKβ-ML) has been proven to effectively target M2 macrophages to repolarize them to M1 phenotype, and inhibit the progression of CNV. Collectively, our findings elucidate that siIKKβ-ML holds the potential to control CNV by reprogramming the macrophage phenotype, indicating a promising therapeutic avenue for CNV management.

Tocilizumab attenuates choroidal neovascularization by regulating macrophage polarization through the IL-6R/STAT3/VEGF pathway

Globally, age-related macular degeneration (AMD) is the leading cause of irreversible visual impairment. Up to 80% of severe vision loss is caused by AMD, which is characterized by the development of choroidal neovascularization (CNV). Uncertainty exists regarding the precise pathophysiological mechanisms of CNV. It has been suggested that the interleukin (IL) IL-6/IL-6R signaling pathway is crucial in the progression of CNV. Tocilizumab (TCZ), a monoclonal antibody, binds to soluble and membrane-bound IL-6R and competitively inhibits IL-6 downstream signaling. Previous research has demonstrated that TCZ promotes several roles related to inflammation and neovascularization. However, the effects of TCZ on CNV and the underlying mechanism are still unknown. This study found that TCZ administration decreased the area and leakage of CNV lesions in the mice model of laser-induced CNV. Additionally, results demonstrated that TCZ promotes the expression of iNOS, CCL-3, CCL-5, TNF-α and inhibits the expression of Arg-1, IL-10, YM-1 and CD206. Furthermore, TCZ treatment inhibited the signal transducer and activator of transcription (STAT) STAT3/vascular endothelial growth factor (VEGF) pathway, which was activated after CNV formation. Colivelin, a STAT3 agonist, reversed the inhibitory effects of TCZ on CNV formation and macrophage polarization. In a mouse model of laser-induced CNV, our findings demonstrated that TCZ attenuated CNV formation and inhibited the leakage of CNV lesions by regulating macrophage polarization via inhibiting the STAT3/VEGF axis. TCZ is the potential therapeutic strategy for CNV.

Chrysin alleviates DNA damage to improve disturbed immune homeostasis and pro-angiogenic environment in laser-induced choroidal neovascularization

Choroidal neovascularization (CNV) is a devastating pathology of numerous ocular diseases, such as wet age-related macular degeneration (wAMD), which causes irreversible vision loss. Although anti-vascular endothelial growth factor (VEGF) therapy has been widely used, poor response or no response still exists in some cases, suggesting that there are other components involved in the angiogenic process. Therefore, the underlying mechanism needs to be clarified and new target of anti-angiogenic therapy is urgently needed. It has been demonstrated that damaged retinal pigment epithelium (RPE) cells can activate inflammasome, driving a degenerative tissue environment and an enhanced pro-angiogenic response, which implies that RPE dysfunction may be a hallmark of the pathogenesis. Previously, we have shown that DNA damage can induce RPE dysfunction, triggering senescence-associated secretory phenotype (SASP) and local inflammation. In this study, we identify that chrysin can reduce DNA damage, especially telomere erosion in vitro, thus compromise the dysfunction of RPE and the decreased expression of SASP factor. Importantly, we find that DNA damage of RPE cells is remarkable in laser-induced CNV lesion, resulting in inflammatory response, which can be ameliorated by chrysin, mainly through IL-17 signaling pathway and its downstream signal transducer and activator of transcription 3 (STAT3) activities. In summary, our results indicate the interplay between DNA damage, perturbed RPE homeostasis, inflammatory response and angiogenesis in laser-induced CNV, and more importantly, chrysin may be an effective therapeutic supplement for CNV.

Monomeric C‐reactive protein exacerbates choroidal neovascularization in vivo: Implications for age‐related macular degeneration

Aims/Purpose: Increased systemic levels of the acute phase reactant C‐reactive protein (CRP) have been linked to increased risk of age‐related macular degeneration (AMD). CRP undergoes conformational changes upon activation in inflammatory microenvironments between pentameric (pCRP) and monomeric forms (mCRP). CRP conformations present different phenotypes, as mCRP has more proinflammatory properties and has been shown to induce blood retinal barrier disruption in vitro. Thus, we aimed to evaluate the impact of CRP forms on choroidal neovascularization (CNV) in vivo.Methods: pCRP and mCRP forms were intravenously (iv) or intravitreally (ivt) injected in C57BL6/J mice (n = 12) previously subjected to CNV induction by laser and compared to controls. CNV lesions were monitored by fluorescein angiography and mice were euthanized 11 days after lesion induction. CNV areas were measured in lectin stained choroidal flatmounts. To evaluate the CRP dissociation, pCRP was coupled to a fluorescent molecule before injection. After tissue extraction mCRP was detected by immunofluorescence in posterior pole flatmounts.Results: Both pCRP and mCRP injected significantly increased CNV areas compared to control mice. Retinal severe edema was also observed close to the lesion in retinographies, and was more severe in intravitreally injected groups. Finally, pCRP was observed to dissociate into mCRP in intravitreally injected animals with pCRP.Conclusions: We confirmed that CRP increases CNV areas and severe edema in the retina, suggesting that CRP is activated in the CNV inflammatory environment. Additionally, the pCRP form dissociates in vivo into mCRP close to CNV damaged tissue, hypothesizing that mCRP is the CRP conformation that contributes to the exacerbation of the CNV process. Further studies are needed to investigate anti‐mCRP molecules as candidates for mono‐ or anti‐VEGF combined therapy for AMD treatments.