Progranulin-deficient macrophages cause cardiotoxicity under hypoxic conditions.

Myocardial infarction (MI) induces structural and electrical cardiac remodeling in response to ischemic insult, causing lethal arrhythmias and sudden death. Progranulin (PGRN) is a glycoprotein mainly expressed in macrophages that modulates the immune responses. In this study, we investigated the direct influence of PGRN knockout (Grn-/-) macrophages on post-MI pathophysiology. An MI mouse model was established by ligating the left coronary artery for RNA sequencing and electrocardiographic analysis. Bone marrow-derived macrophages (BMDMs) were injected into mice and supernatant was collected for the measurement of reactive oxygen species (ROS) levels and extracellular flux analysis. Administration of Grn-/- BMDMs prolonged the QT intervals in the MI mouse model. Moreover, genes highly expressed in macrophages were upregulated in Grn-/- heart after MI. Post-hypoxic supernatant of Grn-/- BMDMs increased the oxygen-glucose deprivation-induced cardiomyocyte death. Grn-/- BMDMs exhibited increased ROS production, oxygen consumption, and extracellular acidification under hypoxia and inflammatory conditions. These findings suggest that PGRN deficiency causes cardiotoxicity via secretory components of macrophages that exhibit metabolic abnormalities under hypoxia.

Progranulin deficiency exacerbates cardiac remodeling after myocardial infarction.

Myocardial infarction (MI) is a lethal disease that causes irreversible cardiomyocyte death and subsequent cardiovascular remodeling. We have previously shown that the administration of recombinant progranulin (PGRN) protects against myocardial ischemia and reperfusion injury. However, the post-MI role of PGRN remains unclear. In the present study, we investigated the effects of PGRN deficiency on cardiac remodeling after MI. Wild-type and PGRN-knockout mice were subjected to MI by ligation of the left coronary artery for histological, electrophysiological, and protein expression analysis. Cardiac macrophage subpopulations were analyzed by flow cytometry. Bone marrow-derived macrophages (BMDMs) were acquired and treated with LPS + IFN-γ and IL-4 to evaluate mRNA levels and phagocytic ability. PGRN expression was gradually increased in the whole heart at 1, 3, and 7 days after MI. Macrophages abundantly expressed PGRN at the border areas at 3 days post-MI. PGRN-knockout mice showed higher mortality, increased LV fibrosis, and severe arrhythmia following MI. PGRN deficiency increased the levels of CD206 and MerTK expression and macrophage infiltration in the infarcted myocardium, which was attributed to a larger subpopulation of cardiac CCR2+ Ly6Clow CD11b+ macrophages. PGRN-deficient BMDMs exhibited higher TGF-ß, IL-4R, and lower IL-1ß, IL-10 and increased acute phagocytosis following stimulation of LPS and IFN-γ. PGRN deficiency reduced survival and increased cardiac fibrosis following MI with the induction of abnormal subpopulation of cardiac macrophages early after MI, thereby providing insight into the relationship between properly initiating cardiac repair and macrophage polarization after MI.

VGF nerve growth factor inducible has the potential to protect pancreatic ß-cells.

VGF nerve growth factor inducible (VGF) is a secreted polypeptide involved in metabolic regulation. VGF-derived peptides have been reported to regulate insulin secretion in the plasma of patients with type 2 diabetes and model mice. However, the protective effects of VGF on pancreatic ß-cells in diabetic model are not well understood. In this study, we aimed to elucidate the ß-cell protective effect of VGF on a streptozotocin (STZ)-induced diabetic model using VGF-overexpressing (OE) mice and also examined the therapeutic effect by a small molecule, SUN N8075 which is an inducer of VGF. VGF-OE mice improved blood glucose levels and maintained ß-cell mass compared to wild-type (WT) mice on STZ-induced diabetic model. In addition, VGF-OE mice showed better glucose tolerance than WT mice. In culture, AQEE-30, a VGF-derived peptide, suppressed STZ-induced ß-cell death in vitro and attenuated the decrease in the phosphorylation of Akt and GSK3ß. Furthermore, SUN N8075 suppressed the blood glucose levels and increased VGF expression in the pancreatic islet. SUN N8075 also protected STZ-induced ß-cell death in vitro. These findings indicate that VGF plays a hypoglycemic role in response to blood glucose levels in diabetes and protects ß-cells from STZ-induced cell death. Therefore, VGF and its inducer have the therapeutic potential by preserving ß-cells in diabetes.

Distribution of Carotenoids and Protective Effects of Zeaxanthin on Retina of Ayu Sweetfish (Plecoglossus altivelis).

Ayu sweetfish (Plecoglossus altivelis) is a diurnal freshwater fish that are surface swimmers and active under broad and short wavelength-dominated light. Biochemical analyses have shown that the ayu fish have abundant carotenoids including zeaxanthin in their integuments. Although zeaxanthin plays an important role in the physiological function of the retina, the amount and location of zeaxanthin in the ayu eye have not been accurately determined. In this study, circular dichroism spectral data and chiral high-performance liquid chromatography analysis showed that zeaxanthin was the primary carotenoid in the ayu eye, and the eye had the highest carotenoid content compared to those in the integuments, subcutaneous fat, and digestive tract. Interestingly, zeaxanthin in the ayu eyeball was expressed in the photoreceptor layer and near the retinal pigmented epithelium. In vitro assays showed that zeaxanthin could protect photoreceptors and retinal pigmented epithelial cell lines against the oxidative stress induced by exposure to L-buthionine-(S,R)-sulfoximine/glutamate. These findings indicate that zeaxanthin plays protective roles against oxidative stress in the vision of wild ayu.

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.

Present and Future Perspectives of Using Human-Induced Pluripotent Stem Cells and Organoid Against Liver Failure.

Organ failure manifests severe symptoms affecting the whole body that may cause death. However, the number of organ donors is not enough for patients requiring transplantation worldwide. Illegal transplantation is also sometimes conducted. To help address this concern, primary hepatocytes are clinically transplanted in the liver. However, donor shortage and host rejection via instant blood-mediated inflammatory reactions are worrisome. Induced pluripotent stem cell-derived hepatocyte-like cells have been developed as an alternative treatment. Recently, organoid technology has been developed to investigate the pathology and mechanism of organoids in cultures. Organoids can be transplanted with vascularization and connected to host blood vessels, and functionally mature better in vivo than in vitro. Hepatic organoids improve pathology in liver disease models. In this review, we introduce induced pluripotent stem cell- and organoid-based therapies against liver diseases considering present and future perspectives.

Potential effects of progranulin and granulins against retinal photoreceptor cell degeneration.

Purpose: The authors previously reported that progranulin attenuated retinal degeneration. The present study focused on the role of progranulin and its cleavage products, granulins, in the pathogenesis of photoreceptor degeneration. Methods: Photoreceptor degeneration was induced with excessive exposure of murine photoreceptor cells and the retinas of albino mice to white fluorescent light. Damaged photoreceptor cells and retinas were examined using a cell death assay, western blotting, and immunostaining. Results: Even after proteolytic cleavage, treatment with progranulin or its cleavage products or both exerted protective effects on photoreceptors against light exposure. In the murine retina, the expression levels of granulins and the macrophage and microglia marker Iba-1 were increased at 48 h after light exposure. Additionally, progranulin+ and Iba-1+ double-positive cells had accumulated in the outer nuclear layer, the primary location of photoreceptor cells. Conclusions: These results suggest that progranulin or its cleavage products, granulins, or both may be therapeutic targets for age-related macular degeneration and other neurodegenerative diseases.

Impaired Cerebellar Development in Mice Overexpressing VGF.

VGF nerve growth factor inducible (VGF) is a neuropeptide precursor induced by brain-derived neurotrophic factor and nerve growth factor. VGF is increased in the prefrontal cortex and cerebrospinal fluid in schizophrenia patients. In our previous study, VGF-overexpressing mice exhibited schizophrenia-like behaviors and smaller brain weights. Brain developmental abnormality is one cause of mental illness. Research on brain development is important for discovery of pathogenesis of mental disorders. In the present study, we investigated the role of VGF on cerebellar development. We performed a histological analysis with cerebellar sections of adult and postnatal day 3 mice by Nissl staining. To investigate cerebellar development, we performed immunostaining with antibodies of immature and mature granule cell markers. To understand the mechanism underlying these histological changes, we examined MAPK, Wnt, and sonic hedgehog signaling by Western blot. Finally, we performed rotarod and footprint tests using adult mice to investigate motor function. VGF-overexpressing adult mice exhibited smaller cerebellar sagittal section area. In postnatal day 3 mice, a cerebellar sagittal section area reduction of the whole cerebellum and external granule layer and a decrease in the number of mature granule cells were found in VGF-overexpressing mice. Additionally, the number of proliferative granule cell precursors was lower in VGF-overexpressing mice. Phosphorylation of Trk and Erk1 were increased in the cerebellum of postnatal day 3 VGF-overexpressing mice. Adult VGF-overexpressing mice exhibited motor disability. All together, these findings implicate VGF in the development of cerebellar granule cells via promoting MAPK signaling and motor function in the adult stage.

Carteolol hydrochloride reduces visible light-induced retinal damage in vivo and BSO/glutamate-induced oxidative stress in vitro.

The purpose of this study was to determine whether carteolol eye drops, a ß-adrenoceptor antagonist used as an intraocular hypotensive agent, has protective effects against the light-induced oxidative stress in retina. Dark-adapted pigmented rats were pre-treated with topical carteolol ophthalmic solution or saline and then exposed to visible light. The effects on electroretinogram (ERG), morphology, oxidative stress, and expression of mRNAs in the retinas were determined. The l-buthionine-(S,R)-sulfoximine (BSO)/glutamate-induced oxidative stress in 661 W cells, a murine photoreceptor cell line, was evaluated by cell death assays, production of reactive oxygen species (ROS), and activation of caspase. In vivo studies showed that exposure to light caused a decrease in the amplitudes of ERGs and the outer nuclear layer (ONL) thickness and an increase of the 8-hydroxy-2'-deoxyguanosine (8-OHdG)-positive cells in the ONL. These changes were significantly reduced by pre-treatment with carteolol. Carteolol also significantly up-regulated the mRNA levels of thioredoxin 1 and glutathione peroxidase 1 compared to saline-treated group. Moreover, carteolol and timolol, another ß-adrenoceptor antagonist, significantly inhibited BSO/glutamate-induced cell death and reduced caspase-3/7 activity and ROS production in vitro. Therefore, carteolol could protect retina from light-induced damage with multiple effects such as enhancing the antioxidative potential and decreasing the intracellular ROS production.

VGF nerve growth factor inducible is involved in retinal ganglion cells death induced by optic nerve crush.

VGF nerve growth factor inducible (VGF) is a polypeptide that is induced by neurotrophic factors and is involved in neurite growth and neuroprotection. The mRNA of the Vgf gene has been detected in the adult rat retina, however the roles played by VGF in the retina are still undetermined. Thus, the purpose of this study was to determine the effects of VGF on the retinal ganglion cells (RGCs) of mice in the optic nerve crush (ONC) model, rat-derived primary cultured RGCs and human induced pluripotent stem cells (iPSCs)-derived RGCs. The mRNA and protein of Vgf were upregulated after the ONC. Immunostaining showed that the VGF was located in glial cells including Müller glia and astrocytes but not in the retinal neurons and their axons. AQEE-30, a VGF peptide, suppressed the loss of RGCs induced by the ONC, and it increased survival rat-derived RGCs and promoted the outgrowth of neurites of rat and human iPSCs derived RGCs in vitro. These findings indicate that VGF plays important roles in neuronal degeneration and has protective effects against the ONC on RGCs. Thus, VGF should be considered as a treatment of RGCs degeneration.

Bilberry extract and anthocyanins suppress unfolded protein response induced by exposure to blue LED light of cells in photoreceptor cell line.

Purpose: The purpose of this study was to investigate the effects of bilberry extract with its anthocyanins on retinal photoreceptor cell damage and on the endoplasmic reticulum (ER) stress induced by exposure to blue light-emitting diode (LED) light. Methods: Cultured murine photoreceptor cells (661W) were exposed to blue LED light with or without bilberry extract or its anthocyanins in the culture media. Aggregated short-wavelength opsin (S-opsin) in murine photoreceptor cells was observed with immunostaining. The expression of factors involved in the unfolded protein response was examined with immunoblot analysis and quantitative real-time reverse transcription (RT)-PCR. Furthermore, cell death was observed with double staining with Hoechst 33342 and propidium iodide after dithiothreitol (DTT) treatment. Results: Bilberry extract and anthocyanins suppressed the aggregation of S-opsin, activation of ATF4, and expression of the mRNA of the factors associated with the unfolded protein response (UPR). In addition, bilberry extract and the anthocyanins inhibited the death of photoreceptor cells induced by DTT, an ER stress inducer. Conclusions: These findings suggest that bilberry extract containing anthocyanins can alter the effects of blue LED light and DTT-induced retinal photoreceptor cell damage. These effects were achieved by modulating the activation of ATF4 and through the suppression of the abnormal aggregation of S-opsin.

Transient acceleration of autophagic degradation by pharmacological Nrf2 activation is important for retinal pigment epithelium cell survival.

Non-exudative age-related macular degeneration (AMD) is mainly caused by the accumulation of lipofuscin and drusen on the retinal pigment epithelium (RPE). Both oxidative stress and autophagic dysfunction accelerate the deposition of lipofuscin at the RPE. One of the key regulators in the response against oxidative stress is the NF-E2-Related Factor 2 (Nrf2)-kelch like ECH associated protein 1 (Keap1) axis, which is also closely associated with the autophagy pathway. Nrf2 activation upregulates the expression levels of certain anti-oxidative enzymes [e.g. Heme oxygenase-1 (HO-1)], which attenuates oxidative damage. However, until now, the relationship between cytoprotective effects of Nrf2 activation and autophagic degradation remain unclear. To address these questions, we investigated the effects of a novel Nrf2 activator, RS9, on RPE damage. We found that RS9 protected ARPE-19 cells against NaIO3-induced oxidative damage, and that the protective effects of RS9 were inhibited by co-treatment with zinc protoporphyrin, an HO-1 inhibitor. Next, we examined the involvement of autophagic degradation in the protective effects of RS9. Co-treatment with RS9 and chloroquine, a lysosomal acidification inhibitor, inhibited the protective effect. Furthermore, western blotting and immunostaining showed that RS9 accelerated autophagy flux and induced transient upregulation of p62 [also known as sequestosome 1 (SQSTM1)]. Co-treatment with chloroquine and RS9 also inhibited the degradation of autophagosomes. Transient upregulation of SQSTM1 by RS9 was unaltered by HO-1 knockdown using siRNA. RS9 and chloroquine had the same actions in light damaged adult zebrafish retina as those in vitro. In conclusion, we clarified the relationship between acceleration of the autophagy pathway and the cytoprotective effects of Nrf2 activation in RPE cells and zebrafish retina. These findings indicated that Nrf2 activation could be a promising therapeutic approach for non-exudative AMD by supporting RPE maintenance.

Intravitreal aflibercept protects photoreceptors of mice against excessive light exposure.

Our previous studies found that an anti-placental growth factor (PlGF) antibody protected the retina in light-induced retinal damage model, a model of non-exudative age-related macular degeneration (AMD). Aflibercept is an inhibitor of vascular endothelial growth factor (VEGF) and PlGF. In present study, we revealed that the intravitreal injection of aflibercept lessens light-induced retinal damage, while anti-VEGF antibody has no effect on the light-exposed retina. Moreover, PlGF disrupted the tight junctions between the human retinal pigment epithelial cells in vitro, and aflibercept blocked the disruption. These data suggest that the aflibercept may be an effective treatment of non-exudative AMD.

Microglia increases the proliferation of retinal precursor cells during postnatal development.

Purpose: In mice, retinal development continues throughout the postnatal stage accompanied by the proliferation of retinal precursor cells. Previous reports showed that during the postnatal stage microglia increase from postnatal day 0 (P0) to P7. However, how microglia are associated with retinal development remains unknown. Methods: The involvement of microglia in retinal development was investigated by two approaches, microglial activation and loss, using lipopolysaccharide (LPS) and PLX3397 (pexidartinib), respectively. Results: LPS injection at 1 mg/kg, intraperitoneally (i.p.) in the neonatal mice increased the number of retinal microglia at P7. 5-Bromo-2´-deoxyuridine (BrdU)-positive proliferative cells were increased by LPS treatment compared to the control group. The proliferative cells were mainly colocalized with paired box 6 (Pax6), a marker of retinal precursor cells. However, the depletion of microglia by treatment with PLX3397 decreased the BrdU-positive proliferative cells. Moreover, progranulin deficiency decreased the number of microglia and retinal precursor cells. Conclusions: These findings indicated that microglia regulate the proliferation of immature retinal cells.

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.

Characterization of an L-Carnitine Transport System in Murine Photoreceptor Cell Line.

While it is well known that L-carnitine [3-hydroxy-4-(trimethylazaniumyl)-butanoate] is an essential molecule for ß-oxidation, it provides anti-oxidative effects as well. Since these effects have been observed in photoreceptor cells, the carnitine's intracellular concentration is considered to play a protective role against oxidative damage to those cells. However, even though its high hydrophilicity makes it likely that carnitine import is accomplished via a dedicated host transport system, the specific uptake process into those cells is currently unknown. Therefore, in this study, we sought to identify and characterize photoreceptor cell carnitine uptake transporter(s) utilizing 661W cells as a photoreceptor cell model. The results of our uptake assays showed that carnitine was transported into 661W cells in a saturable manner (Km=5.5 mM), and that the activity was susceptible to extracellular pH and Na+. While these data suggest the involvement of a transporter in 661W cell carnitine uptake, the observed transport profile did not correspond to any of the currently known carnitine transporters such as organic cation/carnitine transporter 1 (Octn1), Octn2, Octn3, B0,+ and Ct2. In fact, in our experiments, the mRNA expressions for such carnitine transporters in 661W cells were consistently very low and the carnitine transporter substrates did not inhibit the uptake activities. Taken as a whole, our results indicate that carnitine is transported into 661W cells in a carrier-mediated manner. However, since its transport modes cannot be fully explained by known carnitine transporters, it is highly likely that photoreceptor cells utilize a unique molecularly-based carnitine uptake system.

Platelet-Derived Growth Factor-BB Lessens Light-Induced Rod Photoreceptor Damage in Mice.

Purpose: Platelet-derived growth factor (PDGF)-BB is known to have neuroprotective effects against various neurodegenerative disorders. The purpose of this study was to determine whether PDGF-BB can be neuroprotective against light-induced photoreceptor damage in mice. Methods: Mice were exposed to 8000-lux luminance for 3 hours to induce phototoxicity. Two hours before light exposure, the experimental mice were injected with PDGF-BB intravitreally, and the control mice were injected with phosphate-buffered saline. The light-exposed PDGF-BB-injected mice and saline-injected mice were evaluated electroretinographically and histologically. The site and expression levels of PDGFR-ß and PDGF-BB were determined by immunostaining and Western blotting, respectively. The effect of PDGF-BB on light-induced cone and rod photoreceptor damage was also evaluated in vitro in 661W cells, a murine cone photoreceptor cell line, and in primary retinal cell cultures. Results: An intravitreal injection of PDGF-BB significantly reduced the decrease in the amplitudes of the electroretinograms (ERGs) and the thinning of the outer nuclear layer (ONL) induced by the light exposure. It also reduced the number of TUNEL-positive cells in the ONL. PDGFR-ß was expressed in the rod outer segments (OSs) but not the cone OSs. The levels of PDGF-BB and PDGFR-ß were decreased after light irradiation. In addition, PDGF-BB had protective effects against light-induced damage to cells of rod photoreceptors but had no effect on the 661W cells in vitro. Conclusions: These findings indicate that PDGF-BB reduces the degree of light-induced retinal damage by activating PDGFR-ß in rod photoreceptors. These findings suggest that PDGF-BB could play a role in the prevention of degeneration in eyes susceptible to phototoxicity.

The Involvement of the Oxidative Stress in Murine Blue LED Light-Induced Retinal Damage Model.

The aim of study was to establish a mouse model of blue light emitting diode (LED) light-induced retinal damage and to evaluate the effects of the antioxidant N-acetylcysteine (NAC). Mice were exposed to 400 or 800 lx blue LED light for 2 h, and were evaluated for retinal damage 5 d later by electroretinogram amplitude and outer nuclear layer (ONL) thickness. Additionally, we investigated the effect of blue LED light exposure on shorts-wave-sensitive opsin (S-opsin), and rhodopsin expression by immunohistochemistry. Blue LED light induced light intensity dependent retinal damage and led to collapse of S-opsin and altered rhodopsin localization from inner and outer segments to ONL. Conversely, NAC administered at 100 or 250 mg/kg intraperitoneally twice a day, before dark adaptation and before light exposure. NAC protected the blue LED light-induced retinal damage in a dose-dependent manner. Further, blue LED light-induced decreasing of S-opsin levels and altered rhodopsin localization, which were suppressed by NAC. We established a mouse model of blue LED light-induced retinal damage and these findings indicated that oxidative stress was partially involved in blue LED light-induced retinal damage.

Astaxanthin analogs, adonixanthin and lycopene, activate Nrf2 to prevent light-induced photoreceptor degeneration.

Carotenoids, in particular astaxanthin, possess potent antioxidant capabilities. Astaxanthin also induces NF-E2-related factor 2 (Nrf2), which plays a major regulatory role in the antioxidative response. However, little is known whether the carotenoid, by-products of astaxanthin, activate Nrf2. Toward this end, we screened eight astaxanthin analogs for Nrf2 activation in murine photoreceptor cell line, 661 W, by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). In addition, we monitored cell death in 661 W cells pretreated with astaxanthin analogs or only pretreated for 6 h with astaxanthin analogs and then exposed to light. Furthermore, we quantified the reactive oxygen species (ROS) production. Cell death was quantified after light exposure by nuclear staining. Nrf2-controlled genes Ho-1, Nqo-1, and Gclm by qRT-PCR and Nrf2 in the nucleus were upregulated in 661 W cells exposed astaxanthin, adonixanthin, echinenone, and lycopene. Moreover, astaxanthin, adonixanthin, echinenone, ß-carotene, adonirubin, and lycopene, but not canthaxanthin, suppressed ROS production and protected cells against light-induced damage. Moreover, pretreatment with adonixanthin or lycopene only before light exposure protected against light-induced cell damage and Nrf2 silencing canceled these effects. These findings indicate that the more potent astaxanthin analogs, adonixanthin and lycopene, protect against light-induced cell damage through not only an anti-oxidative response but also through Nrf2 activation.

Progranulin deficiency causes the retinal ganglion cell loss during development.

Astrocytes are glial cells that support and protect neurons in the central nervous systems including the retina. Retinal ganglion cells (RGCs) are in contact with the astrocytes and our earlier findings showed the reduction of the number of cells in the ganglion cell layer in adult progranulin deficient mice. In the present study, we focused on the time of activation of the astrocytes and the alterations in the number of RGCs in the retina and optic nerve in progranulin deficient mice. Our findings showed that the number of Brn3a-positive cells was reduced and the expression of glial fibrillary acidic protein (GFAP) was increased in progranulin deficient mice. The progranulin deficient mice had a high expression of GFAP on postnatal day 9 (P9) but not on postnatal day 1. These mice also had a decrease in the number of the Brn3a-positive cells on P9. Taken together, these findings indicate that the absence of progranulin can affect the survival of RGCs subsequent the activation of astrocytes during retinal development.