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.

Timolol maleate, a ß blocker eye drop, improved edema in a retinal vein occlusion model.

Purpose: To investigate the therapeutic effects of eye drops, namely, timolol maleate, a ß-adrenergic receptor antagonist, and latanoprost, a prostaglandin F2α analog, on retinal edema in a murine retinal vein occlusion (RVO) model. Methods: An RVO model was established using laser-induced RVO in mice, which were administered timolol maleate and latanoprost eye drops several times after venous occlusion. Subsequently, the thickness of the inner nuclear layer (INL) and the expression levels of such genes as Vegf and Atf4, which are stress markers of the endoplasmic reticulum, were examined. Primary human cultured retinal microvascular endothelial cells (HRMECs) were treated with timolol under hypoxic conditions, after which the gene expression pattern was investigated. Importantly, an integrated stress response inhibitor (ISRIB) was used in the RVO model, he known ISRIB, which suppresses the expression of ATF4 in retinal edema. Results: Increased INL thickness was suppressed by timolol eye drops, as were the expressions of Vegf and Atf4, in the RVO model. However, latanoprost eye drops did not induce any change in INL thickness. In HRMECs, hypoxic stress and serum deprivation increased the Vegf and Atf4 expressions; in response, treatment with timolol suppressed the Vegf expression. Furthermore, the ISRIB decreased the Vegf expression pattern and edema formation, which are associated with RVO. Conclusions: These results indicate that timolol eye drops may be a potential option for RVO treatment.

TRPV4 channels promote vascular permeability in retinal vascular disease.

This study aimed to determine the role of transient receptor potential vanilloid 4 (TRPV4), a calcium (Ca2+)-permeable cation channel, in the pathophysiology of retinal vascular disease. The retinal vein occlusion (RVO) murine model was created by irradiating retinal veins using lasers. TRPV4 expression and localization were evaluated in RVO mice retinas. In addition, we examined the effects of TRPV4 antagonists (RQ-00317310, HC-067047, GSK2193874, and GSK2798745) on retinal edema, blood flow, and ischemic areas in RVO mice. Furthermore, changes in the retinal expression of tumor necrosis factor (TNF)-α and aquaporin4 (AQP4) by RQ-00317310 were analyzed using Western blot. We also assessed the barrier integrity of epithelial cell monolayers using trans-endothelial electrical resistance (TEER) in Human Retinal Microvascular Endothelial Cells (HRMECs). The expression of TRPV4 was significantly increased and co-localized with glutamine synthetase (GS), a Müller glial marker, in the ganglion cell layer (GCL) of the RVO mice. Moreover, RQ-00317310 administration ameliorated the development of retinal edema and ischemia in RVO mice. In addition, the up regulation of TNF-α and down-regulation of AQP4 were lessened by the treatment with RQ-00317310. Treatment with GSK1016790A, a TRPV4 agonist, increased vascular permeability, while RQ-00317310 treatment decreased vascular endothelial growth factor (VEGF)- or TRPV4-induced retinal vascular hyperpermeability in HRMECs. These findings suggest that TRPV4 plays a role in the development of retinal edema and ischemia. Thus, TRPV4 could be a new therapeutic target against the pathological symptoms of retinal vascular diseases.

The pathological association between the anterior eye segment and the retina in a murine model of neovascular glaucoma.

Neovascular glaucoma (NVG) is caused by the formation of new blood vessels in the angle, iris, and cornea in retinal ischemic disease, such as proliferative diabetic retinopathy (PDR) and retinal vein occlusion (RVO), which can reduce the visual acuity. However, the pathophysiological symptoms of NVG are still not well understood because there is no model for the formation of NVG in the angle, iris, and cornea. The aim of this study was to investigate the involvement of NVG during ischemic disease, in a murine model of retinal ischemia. We evaluated the changes of the intraocular pressure (IOP) and pathological symptoms in the anterior eye segment and retina in this model, and the changes in the RNA or protein expression of vascular endothelial growth factor (VEGF) and fibrosis-related factors were analyzed in the retina and cornea by quantitative real-time polymerase chain reaction or western blot, respectively. Furthermore, we examined the changes in IOP after intravitreal injection of an anti-VEGF antibody. First, NVG formed in the retinal ischemic murine model, and the IOP was elevated in mice with NVG formation. Interestingly, VEGF expression was decreased in the retina but increased in the cornea in the murine model of NVG. On the other hand, fibrosis-related factors were increased in the retina and also significantly increased in the cornea in NVG. Moreover, the administration of anti-VEGF antibody immediately after vessel occlusion suppressed the increase in IOP, but administration at 7 days after vessel occlusion accelerated the increase in IOP. These findings suggest that the formation of NVG may be correlated with the pathological symptoms of retinal ischemic disease, via changes in VEGF and fibrosis-related factor expression.

Arctigenin Prevents Retinal Edema in a Murine Retinal Vein Occlusion Model.

Macular edema causes vision loss in patients with retinal vein occlusion (RVO) and diabetic macular edema (DME). The intravitreal injection of anti-vascular endothelial growth factor (VEGF) agents is used for treatment; however, this therapy is invasive, and recurrence occurs in some cases. The establishment of a non-invasive treatment would help to solve these problems. Here, we focused on arctigenin, a lignan polyphenol found in burdock sprout, and has effects on inflammatory and microcirculatory when taken orally. We hypothesized that oral intake of arctigenin could be effective against retinal edema in RVO and DME. In this study, the degree of retinal edema by measuring the total retinal thickness using optical coherence tomography (OCT) and the thickness of the inner nuclear layer (INL) by hematoxylin-eosin (H&E) staining were investigated. Oral administration of arctigenin ameliorated retinal edema in an RVO murine model by inhibiting the decrease in occludin and vascular endothelial (VE)-cadherin. Moreover, in retinas with edema, arctigenin suppressed the induction of VEGF, tumor necrosis factor α (TNFα), and matrix metallopeptidase 9 (MMP9). Next, the effects of arctigenin on barrier function were assessed in human retinal microvascular endothelial cells (HRMECs) by measuring the trans-endothelial electrical resistance (TEER) and conducting fluorescein isothiocyanate (FITC)-dextran permeability assays. Arctigenin showed a protective effect against VEGF-induced barrier dysfunction. In addition, arctigenin inhibited the TNFα-mediated activation of the nuclear factor-kappaB (NF-κB)/p38 mitogen-activated protein kinase (MAPK) pathway. These results suggested that oral administration of arctigenin has beneficial effects on retinal edema by inhibiting vascular hyperpermeability in endothelial cells.

Excess adiponectin in eyes with progressive ocular vascular diseases.

Anti-vascular endothelial growth factor (VEGF) therapies are now the first-line treatment for many ocular diseases, but some patients are non-responders to these therapies. The purpose of this study was to determine whether the level of adiponectin increased the pathogenesis of retinal edema and neovascularization in the retina of progressive ocular vascular diseases. We examined the role played by adiponectin in two types of cells and animal models which are retinal vein occlusion (RVO) and oxygen-induced retinopathy (OIR) mice. Our results showed that an injection of anti-adiponectin antibody ameliorated the retinal edema and ischemia through the depression of the expression level of VEGF-related factors and tight junction-related proteins in the retina of RVO mice. The intravitreal injection of anti-adiponectin antibody also decreased the degree of retinal neovascularization in an OIR mice. In addition, exposure of human retinal microvascular endothelial cells and human brain microvascular pericytes in culture to adiponectin increased both the vascular permeability and neovascularization through the increase of inflammatory factor and the dropout of the pericytes. These findings indicate that adiponectin plays a critical role in retinal edema and neovascularization, and adiponectin is a potential therapeutic target for the treatment of diabetic macular edema, proliferative diabetic retinopathy, and RVO.

Establishment of a pigmented murine model abundant with characteristics of retinal vein occlusion.

Retinal vein occlusion (RVO) is a vascular disease that represents characteristic retinal hemorrhage and dilated retinal veins. Despite its clinical importance, its pathogenesis remains largely unknown because of limited opportunities to acquire human retinal samples. Therefore, an animal model that reproduces the clinical features of RVO patients is required for further investigation. In this study, we established a pigmented murine RVO model that reproduced characteristic fundus appearances similar to human RVO findings. Retinal edema in this model was observed in both optical coherence tomography and histological analysis, which is a clinically important outcome. With quantitative real-time PCR analysis on retinal samples, we revealed that the mRNA level of vascular endothelial growth factor (VEGF) increased in the retina induced RVO. Moreover, this retinal edema was reduced by intravitreal injection of anti-VEGF antibody. These results were consistent with human clinical knowledge and suggested that this model could be a useful tool for research into new therapeutic approaches.

Oral administration of NSP-116, a free radical scavenger, suppresses the symptoms of retinal vein occlusion in the murine model.

Retinal vein occlusion (RVO) is an intractable eye disease that results in reduced visual acuity, associated with retinal ischemia, hemorrhage, and edema. RVO results in excessive ROS production in the retina, causing inflammation and retinal edema. A free radical scavenger, 4-(4-acetylpiperazin-1-yl)-2-(1H-imidazole-1-yl) aniline (NSP-116), has been reported to demonstrate antioxidative effects and prevent ROS production in the retina. Therefore, NSP-116 may represent a useful drug for treating the pathological symptoms of RVO, such as retinal edema and ischemic symptoms. This study aimed to investigate the effects of NSP-116 in a murine model of RVO. We evaluated the thickness of the retinal layer and the size of the non-perfused area following the oral administration of NSP-116. Moreover, we used western blot analysis to examine the expression levels of vascular endothelial growth factor (VEGF) and tumor necrosis factor (TNF)-α, after NSP-116 administration, and examined the localization of 8-hydroxy-2'-deoxyguanosine (8-OHdG), by immunostaining. The findings indicate that NSP-116 suppressed retinal edema and expansion the non-perfused area by suppressing the increased expression of VEGF, TNF-α, and 8-OHdG in the murine RVO model. In conclusion, the oral administration of NSP-116 may serve as an effective pharmacological treatment for the pathological symptoms of RVO.

Role of Activating Transcription Factor 4 in Murine Choroidal Neovascularization Model.

Neovascular age-related macular degeneration (nAMD) featuring choroidal neovascularization (CNV) is the principal cause of irreversible blindness in elderly people in the world. Integrated stress response (ISR) is one of the intracellular signals to be adapted to various stress conditions including endoplasmic reticulum (ER) stress. ISR signaling results in the upregulation of activating transcription factor 4 (ATF4), which is a mediator of ISR. Although recent studies have suggested ISR contributes to the progression of some age-related disorders, the effects of ATF4 on the development of CNV remain unclear. Here, we performed a murine model of laser-induced CNV and found that ATF4 was highly expressed in endothelial cells of the blood vessels of the CNV lesion site. Exposure to integrated stress inhibitor (ISRIB) reduced CNV formation, vascular leakage, and the upregulation of vascular endothelial growth factor (VEGF) in retinal pigment epithelium (RPE)-choroid-sclera complex. In human retinal microvascular endothelial cells (HRMECs), ISRIB reduced the level of ATF4 and VEGF induced by an ER stress inducer, thapsigargin, and recombinant human VEGF. Moreover, ISRIB decreased the VEGF-induced cell proliferation and migration of HRMECs. Collectively, our findings showed that pro-angiogenic effects of ATF4 in endothelial cells may be a potentially therapeutic target for patients with nAMD.

Oral and ocular administration of crocetin prevents retinal edema in a murine retinal vein occlusion model.

Purpose: We investigated the effects of oral and ocular administration of crocetin in a murine retinal vein occlusion (RVO) model. Crocetin is a type of carotenoid contained in the fruit of gardenia (Gardenia jasminoides Ellis) and the stigma of saffron (Crocus staruts L). Methods: This study was performed on a murine RVO model, which was created by laser irradiation of retinal veins. We evaluated the retinal thickness after the oral administration of crocetin (100 mg/kg) 1 and 6 h before laser irradiation, and immediately, 6 h, 12 h, and 18 h after laser irradiation in the murine RVO model. In addition, we measured the retinal layer thickness after administration of crocetin eye drops (0.03% or 0.10%) immediately, 6 h, and 12 h after laser irradiation. Western blotting of retinal tissue was used to determine the expression levels of matrix metalloproteinase (MMP-9), tumor nuclear factor (TNF-α), and occludin after oral administration of crocetin. Results: Oral and ocular administration of crocetin improved retinal edema in the murine RVO model. Crocetin administration statistically significantly suppressed overexpression of MMP-9 and TNF-α, and reversed the reduction of occludin. Conclusions: These findings indicate that crocetin can protect retinal tight junctions by suppressing retinal edema through an anti-inflammatory effect, which suggests that crocetin may be useful for RVO disease.

Exposure to excessive blue LED light damages retinal pigment epithelium and photoreceptors of pigmented mice.

To determine the characteristics of the damages of the retinal pigment epithelium (RPE) and photoreceptors of pigmented mice induced by exposure to blue light emitting diode (LED) light, and to determine the mechanisms causing the damages. Exposure to blue LED light for 3 days induced retinal damage, and the characteristics of the damage differed from that induced by white fluorescent light exposure. Ophthalmoscopy showed that blue LED exposure for 3 days induced white spots on the retina, and histological examinations showed materials accumulated at the IS/OS junction of the photoreceptors. The accumulated materials were stained by ionized calcium binding adapter molecule-1 (Iba-1), a marker for macrophages. The debris was also positive for periodic acid-Schiff (PAS). An enlarging the area of RPE was detected just after the blue LED exposure especially around the optic nerve, and this led to a secondary degeneration of the photoreceptors. Exposure of pigmented mice to 3 consecutive days of blue LED light will cause RPE and photoreceptor damage. The damage led to an accumulation of macrophages and drusen-like materials around the outer segments of the photoreceptors. This blue light exposed model may be useful for investigating the pathogenesis of non-exudative age-related macular degeneration.

Effects of ripasudil, a ROCK inhibitor, on retinal edema and nonperfusion area in a retinal vein occlusion murine model.

Rho-associated coiled-coil containing protein kinase (ROCK) inhibitors are used to treat glaucoma patients and have protective effects on ischemic states. However, it is poorly understood how the ROCK pathway affects the pathological signs of retinal vein occlusion (RVO). In this study, we evaluated the effects of ripasudil, a ROCK inhibitor, on a murine RVO model. In vivo, RVO was induced by retinal vein laser irradiation in mice, and evaluated with ripasudil. In vitro, the effects of ripasudil were examined on tight junction protein integrity in human retinal microvascular endothelial cells (HRMECs). Moreover, we investigated the expression level of the phosphorylated myosin phosphatase target protein (MYPT)-1 after administration of ripasudil. Ripasudil significantly prevented deterioration, such as retinal edema, reduced the size of the nonperfusion area, and improved retinal blood flow. Ripasudil treatment inhibited disintegration of ZO-1 in HRMECs. Administration of ripasudil suppressed retinal phosphorylation of MYPT-1 in a murine RVO model. These findings indicate that ripasudil might be as a possible therapeutic agent for RVO.

Effects of kallidinogenase on retinal edema and size of non-perfused areas in mice with retinal vein occlusion.

Kallidinogenase has been used to treat retinal vein occlusion (RVO) in patients, although there are no evidences on the effects of kallidinogenase on the retinal edema and the non-perfused areas in eyes with a RVO. We have established a murine RVO model with retinal edema and non-perfused areas. The purpose of this study was to evaluate the effects of kallidinogenase on the retinal edema and size of the non-perfused areas in the mouse RVO model. We evaluated the thickness of the retinal layers and size of the non-perfused areas, and the blood flow by laser speckle flowgraphy in RVO model. The effects of an intravenous injection of kallidinogenase on the retinal edema and size of the non-perfused areas were determined. In addition, the expressions of phosphorylated protein kinase B (Akt) and endothelial nitric oxide synthase (eNOS) were measured by Western blotting. Our results showed that kallidinogenase reduced the degree of retinal edema and size of the non-perfused areas by an increase in the blood flow in RVO model. Kallidinogenase also increased the levels of phosphorylated Akt and eNOS. These findings indicate that kallidinogenase acted through Akt/eNOS-dependent phosphorylation. Thus, kallidinogenase should be considered as a possible therapeutic agent for RVO patients.

Sphingosine-1-phosphate receptor 1/5 selective agonist alleviates ocular vascular pathologies.

Ocular abnormal angiogenesis and edema are featured in several ocular diseases. S1P signaling via S1P1 likely is part of the negative feedback mechanism necessary to maintain vascular health. In this study, we conducted pharmacological experiments to determine whether ASP4058, a sphingosine 1-phosphate receptor 1/5 (S1P1/5) agonist, is useful in abnormal vascular pathology in the eye. First, human retinal microvascular endothelial cells (HRMECs) were examined using vascular endothelial growth factor (VEGF)-induced cell proliferation and hyperpermeability. ASP4058 showed high affinity and inhibited VEGF-induced proliferation and hyperpermeability of HRMECs. Furthermore, S1P1 expression and localization changes were examined in the murine laser-induced choroidal neovascularization (CNV) model, a mouse model of exudative age-related macular degeneration, and the efficacy of ASP4058 was verified. In the CNV model mice, S1P1 tended to decrease in expression immediately after laser irradiation and colocalized with endothelial cells and Müller glial cells. Oral administration of ASP4058 also suppressed vascular hyperpermeability and CNV, and the effect was comparable to that of the intravitreal administration of aflibercept, an anti-VEGF drug. Next, efficacy was also examined in a retinal vein occlusion (RVO) model in which retinal vascular permeability was increased. ASP4058 dose-dependently suppressed the intraretinal edema. In addition, it suppressed the expansion of the perfusion area observed in the RVO model. ASP4058 also suppressed the production of VEGF in the eye. Collectively, ASP4058 can be a potential therapeutic agent that normalizes abnormal vascular pathology, such as age-related macular degeneration and RVO, through its direct action on endothelial cells.

A-910823, a squalene-based emulsion adjuvant, induces T follicular helper cells and humoral immune responses via α-tocopherol component.

Background: Adjuvants are chemical or biological materials that enhance the efficacy of vaccines. A-910823 is a squalene-based emulsion adjuvant used for S-268019-b, a novel vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that is currently in clinical development. Published evidence has demonstrated that A-910823 can enhance the induction of neutralizing antibodies against SARS-CoV-2 in humans and animal models. However, the characteristics and mechanisms of the immune responses induced by A-910823 are not yet known. Methods and Results: To characterize A-910823, we compared the adaptive immune response profile enhanced by A-910823 with that of other adjuvants (AddaVax, QS21, aluminum salt-based adjuvants, and empty lipid nanoparticle [eLNP]) in a murine model. Compared with other adjuvants, A-910823 enhanced humoral immune responses to an equal or greater extent following potent T follicular helper (Tfh) and germinal center B (GCB) cell induction, without inducing a strong systemic inflammatory cytokine response. Furthermore, S-268019-b containing A-910823 adjuvant produced similar results even when given as a booster dose following primary administration of a lipid nanoparticle-encapsulated messenger RNA (mRNA-LNP) vaccine. Preparation of modified A-910823 adjuvants to identify which components of A-910823 play a role in driving the adjuvant effect and detailed evaluation of the immunological characteristics induced by each adjuvant showed that the induction of humoral immunity and Tfh and GCB cell induction in A-910823 were dependent on α-tocopherol. Finally, we revealed that the recruitment of inflammatory cells to the draining lymph nodes and induction of serum cytokines and chemokines by A-910823 were also dependent on the α-tocopherol component. Conclusions: This study demonstrates that the novel adjuvant A-910823 is capable of robust Tfh cell induction and humoral immune responses, even when given as a booster dose. The findings also emphasize that α-tocopherol drives the potent Tfh-inducing adjuvant function of A-910823. Overall, our data provide key information that may inform the future production of improved adjuvants.

Efficacy of an Anti-Semaphorin 3A Neutralizing Antibody in a Male Experimental Retinal Vein Occlusion Mouse Model.

Purpose: Semaphorin 3A (Sema3A) is a promising therapeutic target for macular edema in age-related macular degeneration, diabetic retinopathy, and retinal vein occlusion (RVO). Anti-vascular endothelial growth factors (anti-VEGFs) are the current standard of care for many retinal diseases. This study investigated the Sema3A neutralizing antibody BI-X and/or anti-VEGF therapy (aflibercept) in an RVO mouse model. Treatment efficacy was examined and grouped by timing subsequent to the RVO mouse model induction: efficacy against the onset of intraretinal edema 1 day postinduction and protective effects at 7 days postinduction. Methods: We examined the changes in expression of Sema3A in the retina of an RVO mouse model. In addition, changes in expression of tumor necrosis factor (TNF)-α and semaphorin-related proteins (neuropilin-1 and plexin A1) in the retina upon treatment were analyzed by Western blotting. The effects of BI-X and/or aflibercept were evaluated using measures of retinal edema, blood flow, and thinning of the inner nuclear layer. Results: Induction of vein occlusion in the RVO mouse model significantly increased Sema3A expression in the retina, particularly in the inner nuclear layer. BI-X was effective as a monotherapy and in combination with anti-VEGF therapy, demonstrating a beneficial effect on intraretinal edema and retinal blood flow. Moreover, in the RVO mouse model, BI-X monotherapy normalized the changes in expression of TNF-α and semaphorin-related proteins. Conclusions: These findings support targeting Sema3A to treat intraretinal edema and retinal ischemia.

The Changes in Blood Flow Seen in the Eye after Foot Acupuncture Treatment in Mice.

Acupuncture is used to treat a wide variety of eye diseases, although there is little evidence about the effects of acupuncture treatment and the mechanisms responsible for them. Foot acupuncture treatment has effects in both mice and humans. The purpose of this study was to investigate the effects of acupuncture treatment on ocular blood flow in mice. We evaluated ocular blood flow in C57BL/6J mice after foot acupuncture treatment using laser speckle flowgraphy. The mean blur rate, which is an index of blood flow velocity, was increased in the foot acupuncture group. Our results showed that, after 3 minutes' foot acupuncture, ocular blood flow was significantly increased in both the blood vessels and tissue of the eye in C57BL/6J mice. Thus, performing acupuncture in mice might help to determine its effects. Furthermore, acupuncture is considered to be a possible treatment for ocular disease.

Effects of progranulin on the pathological conditions in experimental myocardial infarction model.

Progranulin is a secreted growth factor associated with multiple physiological functions in ischemic pathophysiology. However, it is still not fully understood how progranulin is involved in ischemic lesion and cardiac remodeling after myocardial infarction (MI). In this study, we investigated the effects of progranulin on myocardial ischemia and reperfusion injury. We investigated progranulin expression using Western blotting and immunostaining after permanent left coronary artery (LCA) occlusion in mice. Infarct size and the number of infiltrating neutrophils were measured 24 h after permanent LCA occlusion. Recombinant mouse progranulin was administered before LCA occlusion. In addition, we evaluated cardiac function using cardiac catheterization and echocardiography, and fibrosis size by Masson's trichrome staining after myocardial ischemia/reperfusion in rabbits. Recombinant human progranulin was administered immediately after induction of reperfusion. Progranulin expression increased in the myocardial ischemic area 1, 3, and 5 days after permanent LCA occlusion in mice. The administration of recombinant mouse progranulin significantly attenuated infarct size and infiltrating neutrophils 24 h after permanent LCA occlusion in mice. We also found that administration of recombinant human progranulin ameliorated the deterioration of cardiac dysfunction and fibrosis after myocardial ischemia/reperfusion in rabbits. These findings suggest that progranulin may protect myocardial ischemia/reperfusion injury.

Nrf2 Activator RS9 Suppresses Pathological Ocular Angiogenesis and Hyperpermeability.

Purpose: Ocular angiogenesis, including retinopathy of prematurity, diabetic retinopathy, and exudative age-related macular degeneration, are closely related to oxidative stress. Many reports have shown that the cellular protective mechanism against oxidative stress and inflammatory response has nuclear factor-erythroid 2-related factor-2 (Nrf2) activity. The aim of this study was to investigate the effectiveness and mechanism of Nrf2 activation in treating the ocular diseases with abnormal vessels. Methods: The effects of Nrf2 activators, bardoxolone methyl (BARD) and RS9, were evaluated against vascular endothelial growth factor (VEGF)-induced cell migration in human retinal microvascular endothelial cells (HRMECs). We measured the expression of the Nrf2 target genes, Ho-1 and Nqo-1 mRNA, in mouse retinas after a single injection of BARD and RS9. The effects and mechanisms of RS9 against retinal angiogenesis were evaluated using an oxygen-induced retinopathy (OIR) model in mice. Moreover, the effect of RS9 against choroidal neovascularization (CNV) was evaluated in a laser-induced CNV monkey model. Results: Both BARD and RS9 decreased VEGF-induced cell migration, and significantly increased Ho-1 mRNA expression; however, only RS9 significantly increased Nqo-1 mRNA. RS9 decreased retinal neovascularization through suppressing VEGF expression and increasing Nrf2, HO-1, platelet-derived growth factor receptor (PDGFR)-ß, and tight junction proteins in OIR murine retinas. Furthermore, RS9 showed a tendency toward decreasing CNV lesions, and improved vascular leakage in a CNV monkey model. Conclusions: These data indicate that a Nrf2 activator might be a candidate for treatment of ocular diseases characterized by pathophysiological angiogenesis and hyperpermeability.

Irreversible Photoreceptors and RPE Cells Damage by Intravenous Sodium Iodate in Mice Is Related to Macrophage Accumulation.

Purpose: To determine the mechanism causing degeneration of the retinal pigment epithelium (RPE) and photoreceptors in mice after an intravenous injection of sodium iodate (NaIO3). Methods: The time-dependent changes in NaIO3-induced retinal degeneration were determined by analyzing the retinal morphology by optical coherence tomographic (OCT) images, histological sections of the retina, physiology of the retina by electroretinography (ERG), and retinal blood flow by laser speckle flowgraphy. In addition, the expression of the genes associated with age-related macular degeneration in humans was assessed in the NaIO3-treated mice by RT-PCR. We also investigated whether macrophages were involved in the NaIO3-induced retinal degeneration. Results: The intravenous injection of 20 mg/kg NaIO3 altered the morphology of the RPE cells and the ERGs transiently. With 40 mg/kg of NaIO3, the degeneration of the RPE cells was still present at 28 days. Aggregated melanin granules were surrounded by zonula occludens protein 1 (ZO-1)-positive cells. In addition, 40 mg/kg of NaIO3 led to a reduction in the amplitudes of the a- and b-waves of the dark-adapted ERGs. Histological studies showed that macrophages had infiltrated the retina and were present around the altered RPE cells. Depletion of the macrophages by a prior injection of clodronate liposomes prevented the damage of the outer retina after the NaIO3 injection but not the RPE. Conclusions: The NaIO3-induced retinal damage was reversible at low concentrations but permanent at high concentrations of NaIO3. The accumulation of macrophages around the RPE cells caused the photoreceptor cell death.