研究者詳細 - 富田　洋平

論文 - 富田　洋平

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Associations between fatty acid intake and diabetic retinopathy in a Japanese population

Sasaki M., Yuki K., Hanyuda A., Yamagishi K., Motomura K., Kurihara T., Tomita Y., Mori K., Ozawa N., Ozawa Y., Sawada N., Negishi K., Tsubota K., Tsugane S., Iso H.

Scientific Reports （Scientific Reports） 13 （ 1 ） 2023年12月

Residents of Chikusei City, aged 40–74 years, underwent systemic and ophthalmological screening, and participants with diabetes were included in this analysis. Dietary intake was assessed using a food frequency questionnaire and calculated as a percentage of the total energy. The presence of diabetic retinopathy (DR) was defined as Early Treatment Diabetic Retinopathy Study levels ≥ 20 in either eye. The association between dietary fatty acid intake and DR has been examined in a cross-sectional study. Among the 647 diabetic participants, 100 had DR. The mean total fat and saturated fatty acid (SFA) intakes were 22.0% and 7.3% of the total energy intake, respectively. After adjusting for potential confounders, the highest quartiles of total fat and SFA intake were positively associated with the presence of DR compared with the lowest quartiles (odds ratios (95% confidence intervals), 2.61 (1.07–6.39), p for trend = 0.025, and 2.40 (1.12–5.17), p for trend = 0.013, respectively). No significant associations were found between DR prevalence and monounsaturated or unsaturated fatty acid intake. These results suggest that a high intake of fat and SFA may affect the development of DR, even in individuals whose total fat intake is generally much lower than that of Westerners.

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Pemafibrate, a potent selective peroxisome proliferator-activated receptor α modulator, a promising novel treatment for ischemic retinopathy?

Lee D., Tomita Y., Negishi K., Kurihara T.

Neural Regeneration Research （Neural Regeneration Research） 18 （ 7 ） 1495 - 1496 2023年07月

ISSN 16735374

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Therapeutic roles of PPARα activation in ocular ischemic diseases

Lee D., Tomita Y., Negishi K., Kurihara T.

Histology and Histopathology （Histology and Histopathology） 38 （ 4 ） 391 - 401 2023年04月

ISSN 02133911

Ocular ischemia is one of the leading causes of blindness. It is related to various ocular diseases and disorders, including age-related macular degeneration, diabetic retinopathy, glaucoma, and corneal injury. Ocular ischemia occurs due to an abnormal supply of oxygen and nutrients to the eye, resulting in ocular metabolic dysfunction. These changes can be linked with pathologic conditions in the eye, such as inflammation, neovascularization, and cell death, ultimately leading to vision loss. The current treatment care for ocular ischemia is limited. Peroxisome proliferator-activated recept or α (PPARα) i s a nucl ear recept or prot ei n functioning in regulating lipid metabolism, fatty acid oxidation, and glucose homeostasis. Recently, PPARα activation has been suggested as a useful therapeutic t arget i n t r eat i ng ocul ar i schemi a. However, i t s applications have not been well summarized. In this review, we cover an overview of the therapeutic roles of PPARα activation in various ocular ischemic conditions with recent experimental evidence and further provide clinical implications of its therapeutic applications. Our review will enable more approaches to comprehensively understand the therapeutic roles of PPARα activation for preventing ocular ischemic diseases.

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Molecular and Cellular Regulations in the Development of the Choroidal Circulation System

Imanishi S., Tomita Y., Negishi K., Tsubota K., Kurihara T.

International Journal of Molecular Sciences （International Journal of Molecular Sciences） 24 （ 6 ） 2023年03月

ISSN 16616596

Disorders in the development and regulation of blood vessels are involved in various ocular disorders, such as persistent hyperplastic primary vitreous, familial exudative vitreoretinopathy, and choroidal dystrophy. Thus, the appropriate regulation of vascular development is essential for healthy ocular functions. However, regulation of the developing choroidal circulation system has not been well studied compared with vascular regulation in the vitreous and the retina. The choroid is a vascular-rich and uniquely structured tissue supplying oxygen and nutrients to the retina, and hypoplasia and the degeneration of the choroid are involved in many ocular disorders. Therefore, understanding the developing choroidal circulation system expands our knowledge of ocular development and supports our understanding of ocular disorders. In this review, we examine studies on regulating the developing choroidal circulation system at the cellular and molecular levels and discuss the relevance to human diseases.

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Pemafibrate prevents choroidal neovascularization in a mouse model of neovascular age-related macular degeneration

Lee D., Nakai A., Miwa Y., Negishi K., Tomita Y., Kurihara T.

PeerJ （PeerJ） 11 2023年01月

Background. Pathological choroidal neovascularization (CNV) is one of the major causes of visual impairment in neovascular age-related macular degeneration (AMD). CNV has been suppressed by using anti-vascular endothelial growth factor (VEGF) antibodies. However, some clinical cases have demonstrated the failure of anti-VEGF therapies. Furthermore, anti-VEGF agents might induce the development of ocular atrophy. Recently, peroxisome proliferator-activated receptor alpha (PPARα) activation using pemafibrate treatment was suggested as one of the promising therapeutic targets in the prevention of ocular ischemia. However, the preventive role of pemafibrate remains unclear in CNV. We aimed to examine the preventive role of pemafibrate on laser-induced pathological CNV. Methods. Adult male C57BL/6 mice were orally supplied pemafibrate (0.5 mg/kg) for four days, followed by laser irradiation. Then, pemafibrate was consecutively given to mice with the same condition. CNV was visualized with isolectin-IB4. The eye (retina and/or retinal pigment epithelium [RPE]-choroid), liver, and serum were used for biomolecular analyses. Results. We found that pemafibrate administration suppressed CNV volumes. Pemafibrate administration activated PPARα downstream genes in the liver and eye (especially, RPE-choroid). Furthermore, pemafibrate administration elevated serum fibroblast growth factor 21 levels and reduced serum levels of triglycerides. Conclusions. Our data suggest a promising pemafibrate therapy for suppressing CNV in AMD.

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Association Between Fatty Acid Intakes and Age-Related Macular Degeneration in a Japanese Population: JPHC-NEXT Eye Study

Yasukawa T., Sasaki M., Motomura K., Yuki K., Kurihara T., Tomita Y., Mori K., Ozawa N., Ozawa Y., Yamagishi K., Hanyuda A., Sawada N., Tsubota K., Tsugane S., Iso H.

Translational Vision Science and Technology （Translational Vision Science and Technology） 12 （ 1 ） 2023年01月

Purpose: To determine the associations between fatty acid intakes and the prevalence of age-related macular degeneration (AMD) under a population-based cross-sectional study. Methods: Residents of Chikusei City aged ≥40 years underwent systemic and eye screening. AMD was graded according to a modified version of the Age-Related Eye Disease Study classification. Dietary intake was assessed using a food frequency questionnaire and was adjusted for total energy intake. Results: Altogether, 10,788 eyes of 5394 participants, 2116 men (mean [standard devia-tion (SD)] age, 62.4 [9.4] years) and 3278 women (60.6 [9.5] years), were included. The mean daily total fat intakes were 52.8 g and 59.0 g in men and women, respectively. After adjustments for potential confounders, saturated fatty acid (SFA) intake was inversely associated with the prevalence of any AMD in men (for each energy-adjusted 1-SD increase: odds ratio [OR], 0.86; 95% confidence interval [CI], 0.74–1.00). Significant trends were found for decreasing odds ratios of AMD with increasing SFA, monounsaturated fatty acid (MUFA), and polyunsaturated fatty acid (PUFA) intake (P for trend = 0.02, 0.04, and 0.04, respectively). In women, only a significant association was observed between the second quartile of linolenic acid intake and the prevalence of any AMD (OR, 0.78; 95% CI, 0.62–0.99). Conclusions: We found an inverse association of SFA intake and a weak inverse association of MUFA and PUFA intakes with the prevalence of any AMD in a Japanese popula-tion. Translational Relevance: Adequate fatty acid intake may be necessary to prevent or decelerate AMD.

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Nicotinamide mononucleotide, a potential future treatment in ocular diseases

Lee D., Tomita Y., Shinojima A., Ban N., Yamaguchi S., Nishioka K., Negishi K., Yoshino J., Kurihara T.

Graefe's Archive for Clinical and Experimental Ophthalmology （Graefe's Archive for Clinical and Experimental Ophthalmology） 2023年

ISSN 0721832X

Purpose: The burden of ocular diseases has been gradually increasing worldwide. Various factors are suggested for the development and progression of ocular diseases, such as ocular inflammation, oxidative stress, and complex metabolic dysregulation. Thus, managing ocular diseases requires the modulation of pathologic signaling pathways through many mechanisms. Nicotinamide mononucleotide (NMN) is a bioactive molecule naturally found in life forms. NMN is a direct precursor of the important molecule nicotinamide adenine dinucleotide (NAD+), an essential co-enzyme required for enormous cellular functions in most life forms. While the recent experimental evidence of NMN treatment in various metabolic diseases has been well-reviewed, NMN treatment in ocular diseases has not been comprehensively summarized yet. In this regard, we aimed to focus on the therapeutic roles of NMN treatment in various ocular diseases with recent advances. Methods: How we came to our current opinion with a recent summary was described based on our own recent reports as well as a search of the related literature. Results: We found that NMN treatment might be available for the prevention of and protection from various experimental ocular diseases, as NMN treatment modulated ocular inflammation, oxidative stress, and complex metabolic dysregulation in murine models for eye diseases such as ischemic retinopathy, corneal defect, glaucoma, and age-related macular degeneration. Conclusion: Our current review suggests and discusses new modes of actions of NMN for the prevention of and protection from various ocular diseases and can urge future research to obtain more solid evidence on a potential future NMN treatment in ocular diseases at the preclinical stages.

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Nicotinamide Mononucleotide Protects against Retinal Dysfunction in a Murine Model of Carotid Artery Occlusion

Lee D., Tomita Y., Miwa Y., Jeong H., Shinojima A., Ban N., Yamaguchi S., Nishioka K., Negishi K., Yoshino J., Kurihara T.

International Journal of Molecular Sciences （International Journal of Molecular Sciences） 23 （ 23 ） 2022年12月

ISSN 16616596

Cardiovascular abnormality-mediated retinal ischemia causes severe visual impairment. Retinal ischemia is involved in enormous pathological processes including oxidative stress, reactive gliosis, and retinal functional deficits. Thus, maintaining retinal function by modulating those pathological processes may prevent or protect against vision loss. Over the decades, nicotinamide mononucleotide (NMN), a crucial nicotinamide adenine dinucleotide (NAD+) intermediate, has been nominated as a promising therapeutic target in retinal diseases. Nonetheless, a protective effect of NMN has not been examined in cardiovascular diseases-induced retinal ischemia. In our study, we aimed to investigate its promising effect of NMN in the ischemic retina of a murine model of carotid artery occlusion. After surgical unilateral common carotid artery occlusion (UCCAO) in adult male C57BL/6 mice, NMN (500 mg/kg/day) was intraperitoneally injected to mice every day until the end of experiments. Electroretinography and biomolecular assays were utilized to measure ocular functional and further molecular alterations in the retina. We found that UCCAO-induced retinal dysfunction was suppressed, pathological gliosis was reduced, retinal NAD+ levels were preserved, and the expression of an antioxidant molecule (nuclear factor erythroid-2-related factor 2; Nrf2) was upregulated by consecutive administration of NMN. Our present outcomes first suggest a promising NMN therapy for the suppression of cardiovascular diseases-mediated retinal ischemic dysfunction.

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Nicotinamide Mononucleotide Prevents Retinal Dysfunction in a Mouse Model of Retinal Ischemia/Reperfusion Injury

Lee D., Tomita Y., Miwa Y., Shinojima A., Ban N., Yamaguchi S., Nishioka K., Negishi K., Yoshino J., Kurihara T.

International Journal of Molecular Sciences （International Journal of Molecular Sciences） 23 （ 19 ） 2022年10月

ISSN 16616596

Retinal ischemia/reperfusion (I/R) injury can cause severe vision impairment. Retinal I/R injury is associated with pathological increases in reactive oxygen species and inflammation, resulting in retinal neuronal cell death. To date, effective therapies have not been developed. Nicotinamide mononucleotide (NMN), a key nicotinamide adenine dinucleotide (NAD+) intermediate, has been shown to exert neuroprotection for retinal diseases. However, it remains unclear whether NMN can prevent retinal I/R injury. Thus, we aimed to determine whether NMN therapy is useful for retinal I/R injury-induced retinal degeneration. One day after NMN intraperitoneal (IP) injection, adult mice were subjected to retinal I/R injury. Then, the mice were injected with NMN once every day for three days. Electroretinography and immunohistochemistry were used to measure retinal functional alterations and retinal inflammation, respectively. The protective effect of NMN administration was further examined using a retinal cell line, 661W, under CoCl2-induced oxidative stress conditions. NMN IP injection significantly suppressed retinal functional damage, as well as inflammation. NMN treatment showed protective effects against oxidative stress-induced cell death. The antioxidant pathway (Nrf2 and Hmox-1) was activated by NMN treatment. In conclusion, NMN could be a promising preventive neuroprotective drug for ischemic retinopathy.

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Cytochrome P450 oxidase 2J inhibition suppresses choroidal neovascularization in mice

Gong Y., Tomita Y., Edin M.L., Ren A., Ko M., Yang J., Bull E., Zeldin D.C., Hellström A., Fu Z., Smith L.E.H.

Metabolism: Clinical and Experimental （Metabolism: Clinical and Experimental） 134 2022年09月

ISSN 00260495

Introduction: Choroidal neovascularization (CNV) in age-related macular degeneration (AMD) leads to blindness. It has been widely reported that increased intake of ω−3 long-chain polyunsaturated fatty acids (LCPUFA) diets reduce CNV. Of the three major pathways metabolizing ω−3 (and ω−6 LCPUFA), the cyclooxygenase and lipoxygenase pathways generally produce pro-angiogenic metabolites from ω−6 LCPUFA and anti-angiogenic ones from ω−3 LCPUFA. Howevehr, cytochrome P450 oxidase (CPY) 2C produces pro-angiogenic metabolites from both ω−6 and ω−3 LCPUFA. The effects of CYP2J2 products on ocular neovascularization are still unknown. Understanding how each metabolic pathway affects the protective effect of ω−3 LCPUFA on retinal neovascularization may lead to therapeutic interventions. Objectives: To investigate the effects of LCPUFA metabolites through CYP2J2 pathway and CYP2J2 regulation on CNV both in vivo and ex vivo. Methods: The impact of CYP2J2 overexpression and inhibition on neovascularization in the laser-induced CNV mouse model was assessed. The plasma levels of CYP2J2 metabolites were measured by liquid chromatography and tandem mass spectroscopy. The choroidal explant sprouting assay was used to investigate the effects of CYP2J2 inhibition and specific LCPUFA CYP2J2 metabolites on angiogenesis ex vivo. Results: CNV was exacerbated in Tie2-Cre CYP2J2-overexpressing mice and was associated with increased levels of plasma docosahexaenoic acids. Inhibiting CYP2J2 activity with flunarizine decreased CNV in both ω−6 and ω−3 LCPUFA-fed wild-type mice. In Tie2-Cre CYP2J2-overexpressing mice, flunarizine suppressed CNV by 33 % and 36 % in ω−6, ω−3 LCPUFA diets, respectively, and reduced plasma levels of CYP2J2 metabolites. The pro-angiogenic role of CYP2J2 was corroborated in the choroidal explant sprouting assay. Flunarizine attenuated ex vivo choroidal sprouting, and 19,20-EDP, a ω−3 LCPUFA CYP2J2 metabolite, increased sprouting. The combined inhibition of CYP2J2 with flunarizine and CYP2C8 with montelukast further enhanced CNV suppression via tumor necrosis factor-α suppression. Conclusions: CYP2J2 inhibition augmented the inhibitory effect of ω−3 LCPUFA on CNV. Flunarizine suppressed pathological choroidal angiogenesis, and co-treatment with montelukast inhibiting CYP2C8 further enhanced the effect. CYP2 inhibition might be a viable approach to suppress CNV in AMD.

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Retinal degeneration induced in a mouse model of ischemia–reperfusion injury and its management by pemafibrate treatment

Lee D., Nakai A., Miwa Y., Tomita Y., Kunimi H., Chen J., Ikeda S.I., Tsubota K., Negishi K., Kurihara T.

FASEB Journal （FASEB Journal） 36 （ 9 ） 2022年09月

ISSN 08926638

Retinal ischemia–reperfusion (I/R) injury is a common cause of visual impairment. To date, no effective treatment is available for retinal I/R injury. In addition, the precise pathological mechanisms still need to be established. Recently, pemafibrate, a peroxisome proliferator-activated receptor α (PPARα) modulator, was shown to be a promising drug for retinal ischemia. However, the role of pemafibrate in preventing retinal I/R injury has not been documented. Here, we investigated how retinal degeneration occurs in a mouse model of retinal I/R injury by elevation of intraocular pressure and examined whether pemafibrate could be beneficial against retinal degeneration. Adult mice were orally administered pemafibrate (0.5 mg/kg/day) for 4 days, followed by retinal I/R injury. The mice were continuously administered pemafibrate once every day until the end of the experiments. Retinal functional changes were measured using electroretinography. Retina, liver, and serum samples were used for western blotting, quantitative PCR, immunohistochemistry, or enzyme linked immunosorbent assay. Retinal degeneration induced by retinal inflammation was prevented by pemafibrate administration. Pemafibrate administration increased the hepatic PPARα target gene expression and serum levels of fibroblast growth factor 21, a neuroprotective molecule in the eye. The expression of hypoxia-response and pro-and anti-apoptotic/inflammatory genes increased in the retina following retinal I/R injury; however, these changes were modulated by pemafibrate administration. In conclusion, pemafibrate is a promising preventive drug for ischemic retinopathies.

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Endothelial Cell Transcytosis Assay as an In Vitro Model to Evaluate Inner Blood-Retinal Barrier Permeability

Bora K., Wang Z., Yemanyi F., Maurya M., Blomfield A.K., Tomita Y., Chen J.

Journal of Visualized Experiments （Journal of Visualized Experiments） 2022 （ 184 ） 2022年06月

ISSN 1940087X

Dysfunction of the blood-retinal barrier (BRB) contributes to the pathophysiology of several vascular eye diseases, often resulting in retinal edema and subsequent vision loss. The inner blood-retinal barrier (iBRB) is mainly composed of retinal vascular endothelium with low permeability under physiological conditions. This feature of low permeability is tightly regulated and maintained by low rates of paracellular transport between adjacent retinal microvascular endothelial cells, as well as transcellular transport (transcytosis) through them. The assessment of retinal transcellular barrier permeability may provide fundamental insights into iBRB integrity in health and disease. In this study, we describe an endothelial cell (EC) transcytosis assay, as an in vitro model for evaluating iBRB permeability, using human retinal microvascular endothelial cells (HRMECs). This assay assesses the ability of HRMECs to transport transferrin and horseradish peroxidase (HRP) in receptor-and caveolae-mediated transcellular transport processes, respectively. Fully confluent HRMECs cultured on porous membrane were incubated with fluorescent-tagged transferrin (clathrin-dependent transcytosis) or HRP (caveolae-mediated transcytosis) to measure the levels of transferrin or HRP transferred to the bottom chamber, indicative of transcytosis levels across the EC monolayer. Wnt signaling, a known pathway regulating iBRB, was modulated to demonstrate the caveolae-mediated HRP-based transcytosis assay method. The EC transcytosis assay described here may provide a useful tool for investigating the molecular regulators of EC permeability and iBRB integrity in vascular pathologies and for screening drug delivery systems.

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Ocular Ischemic Syndrome and Its Related Experimental Models

Lee D., Tomita Y., Yang L., Negishi K., Kurihara T.

International Journal of Molecular Sciences （International Journal of Molecular Sciences） 23 （ 9 ） 2022年05月

ISSN 16616596

Ocular ischemic syndrome (OIS) is one of the severe ocular disorders occurring from stenosis or occlusion of the carotid arteries. As the ophthalmic artery is derived from the branch of the carotid artery, stenosis or occlusion of the carotid arteries could induce chronic ocular hypoperfusion, finally leading to the development of OIS. To date, the pathophysiology of OIS is still not clearly unraveled. To better explore the pathophysiology of OIS, several experimental models have been developed in rats and mice. Surgical occlusion or stenosis of common carotid arteries or internal carotid arteries was conducted bilaterally or unilaterally for model development. In this regard, final ischemic outcomes in the eye varied depending on the surgical procedure, even though similar findings on ocular hypoperfusion could be observed. In the current review, we provide an overview of the pathophysiology of OIS from various experimental models, as well as several clinical cases. Moreover, we cover the status of current therapies for OIS along with promising preclinical treatments with recent advances. Our review will enable more comprehensive therapeutic approaches to prevent the development and/or progression of OIS.

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Non-Perfusion Area Index for Prognostic Prediction in Diabetic Retinopathy

Ofuji Y., Katada Y., Tomita Y., Nagai N., Sonobe H., Watanabe K., Shinoda H., Ozawa Y., Negishi K., Tsubota K., Kurihara T.

Life （Life） 12 （ 4 ） 2022年04月

Fundus fluorescent angiography is a standard examination in Japan that can directly visualize the circulatory failure in diabetic retinopathy but is not used in Western countries. In this study, we examine the relationship between the non-perfusion area in fundus fluorescent angiography and the progression of diabetic retinopathy. We evaluated 22 eyes between 22 patients who had their first fundus fluorescent angiography during a clinical episode at Keio University Hospital from January 2012 to May 2015, were diagnosed as having preproliferative diabetic retinopathy, and could be followed for at least three years. The non-perfusion area index (%) in nine segmented fundi in the initial fundus fluorescent angiography was calculated, and the progression to proliferative diabetic retinopathy over three years was evaluated. Three out of the 22 eyes (13.6%) developed proliferative diabetic retinopathy over three years. The non-perfusion area index for the initial fundus fluorescent angiography was significantly associated with progression to proliferative diabetic retinopathy. The non-perfusion area index in the posterior pole was most strongly correlated with the progression to proliferative diabetic retinopathy. Thus, the non-perfusion area index in the posterior pole among those with preproliferative diabetic retinopathy may predict the progression to proliferative diabetic retinopathy in the subsequent three years.

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Amino acid transporter SLC38A5 regulates developmental and pathological retinal angiogenesis

Wang Z., Yemanyi F., Blomfield A.K., Bora K., Huang S., Liu C.H., Britton W.R., Cho S.S., Tomita Y., Fu Z., Ma J.X., Li W.H., Chen J.

eLife （eLife） 11 2022年

Amino acid (AA) metabolism in vascular endothelium is important for sprouting angio-genesis. SLC38A5 (solute carrier family 38 member 5), an AA transporter, shuttles neutral AAs across cell membrane, including glutamine, which may serve as metabolic fuel for proliferating endothelial cells (ECs) to promote angiogenesis. Here, we found that Slc38a5 is highly enriched in normal retinal vascular endothelium, and more specifically, in pathological sprouting neovessels. Slc38a5 is suppressed in retinal blood vessels from Lrp5−/− and Ndpy/− mice, both genetic models of defec-tive retinal vascular development with Wnt signaling mutations. Additionally, Slc38a5 transcription is regulated by Wnt/β-catenin signaling. Genetic deficiency of Slc38a5 in mice substantially delays retinal vascular development and suppresses pathological neovascularization in oxygen-induced retinopathy modeling ischemic proliferative retinopathies. Inhibition of SLC38A5 in human retinal vascular ECs impairs EC proliferation and angiogenic function, suppresses glutamine uptake, and dampens vascular endothelial growth factor receptor 2. Together these findings suggest that SLC38A5 is a new metabolic regulator of retinal angiogenesis by controlling AA nutrient uptake and homeostasis in ECs.

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Pparα modulation-based therapy in central nervous system diseases

Lee D., Tomita Y., Allen W., Tsubota K., Negishi K., Kurihara T.

Life （Life） 11 （ 11 ） 2021年11月

The burden of neurodegenerative diseases in the central nervous system (CNS) is increasing globally. There are various risk factors for the development and progression of CNS diseases, such as inflammatory responses and metabolic derangements. Thus, curing CNS diseases requires the modulation of damaging signaling pathways through a multitude of mechanisms. Peroxisome proliferator-activated receptors (PPARs) are a family of nuclear hormone receptors (PPARα, PPARβ/δ, and PPARγ), and they work as master sensors and modulators of cellular metabolism. In this regard, PPARs have recently been suggested as promising therapeutic targets for suppressing the development of CNS diseases and their progressions. While the therapeutic role of PPARγ modulation in CNS diseases has been well reviewed, the role of PPARα modulation in these diseases has not been comprehensively summarized. The current review focuses on the therapeutic roles of PPARα modulation in CNS diseases, including those affecting the brain, spinal cord, and eye, with recent advances. Our review will enable more comprehensive therapeutic approaches to modulate PPARα for the prevention of and protection from various CNS diseases.

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Metabolism in retinopathy of prematurity

Tomita Y., Usui-Ouchi A., Nilsson A.K., Yang J., Ko M., Hellström A., Fu Z.

Life （Life） 11 （ 11 ） 2021年11月

Retinopathy of prematurity is defined as retinal abnormalities that occur during development as a consequence of disturbed oxygen conditions and nutrient supply after preterm birth. Both neuronal maturation and retinal vascularization are impaired, leading to the compensatory but uncontrolled retinal neovessel growth. Current therapeutic interventions target the hypoxia-induced neovessels but negatively impact retinal neurons and normal vessels. Emerging evidence suggests that metabolic disturbance is a significant and underexplored risk factor in the disease pathogenesis. Hyperglycemia and dyslipidemia correlate with the retinal neurovascular dysfunction in infants born prematurely. Nutritional and hormonal supplementation relieve metabolic stress and improve retinal maturation. Here we focus on the mechanisms through which metabolism is involved in preterm-birth-related retinal disorder from clinical and experimental investigations. We will review and discuss potential therapeutic targets through the restoration of metabolic responses to prevent disease development and progression.

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Myeloid lineage contributes to pathological choroidal neovascularization formation via SOCS3

Wang T., Zhou P., Xie X., Tomita Y., Cho S., Tsirukis D., Lam E., Luo H.R., Sun Y.

EBioMedicine （EBioMedicine） 73 2021年11月

Background: Pathological neovascularization in neovascular age-related macular degeneration (nAMD) is the leading cause of vision loss in the elderly. Increasing evidence shows that cells of myeloid lineage play important roles in controlling pathological endothelium formation. Suppressor of cytokine signaling 3 (SOCS3) pathway has been linked to neovascularization. Methods: We utilised a laser-induced choroidal neovascularization (CNV) mouse model to investigate the neovascular aspect of human AMD. In several cell lineage reporter mice, bone marrow chimeric mice and Socs3 loss-of-function (knockout) and gain-of-function (overexpression) mice, immunohistochemistry, confocal, and choroidal explant co-culture with bone marrow-derived macrophage medium were used to study the mechanisms underlying pathological CNV formation via myeloid SOCS3. Findings: SOCS3 was significantly induced in myeloid lineage cells, which were recruited into the CNV lesion area. Myeloid Socs3 overexpression inhibited laser-induced CNV, reduced myeloid lineage-derived macrophage/microglia recruitment onsite, and attenuated pro-inflammatory factor expression. Moreover, SOCS3 in myeloid regulated vascular sprouting ex vivo in choroid explants and SOCS3 agonist reduced in vivo CNV. Interpretation: These findings suggest that myeloid lineage cells contributed to pathological CNV formation regulated by SOCS3. Funding: This project was funded by NIH/NEI (R01EY030140, R01EY029238), BrightFocus Foundation, American Health Assistance Foundation (AHAF), and Boston Children's Hospital Ophthalmology Foundation for YS and the National Institutes of Health/National Heart, Lung and Blood Institute (U01HL098166) for PZ.

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Müller glial responses compensate for degenerating photoreceptors in retinitis pigmentosa

Tomita Y., Qiu C., Bull E., Allen W., Kotoda Y., Talukdar S., Smith L.E.H., Fu Z.

Experimental and Molecular Medicine （Experimental and Molecular Medicine） 53 （ 11 ） 1748 - 1758 2021年11月

ISSN 12263613

Photoreceptor degeneration caused by genetic defects leads to retinitis pigmentosa, a rare disease typically diagnosed in adolescents and young adults. In most cases, rod loss occurs first, followed by cone loss as well as altered function in cells connected to photoreceptors directly or indirectly. There remains a gap in our understanding of retinal cellular responses to photoreceptor abnormalities. Here, we utilized single-cell transcriptomics to investigate cellular responses in each major retinal cell type in retinitis pigmentosa model (P23H) mice vs. wild-type littermate mice. We found a significant decrease in the expression of genes associated with phototransduction, the inner/outer segment, photoreceptor cell cilium, and photoreceptor development in both rod and cone clusters, in line with the structural changes seen with immunohistochemistry. Accompanying this loss was a significant decrease in the expression of genes involved in metabolic pathways and energy production in both rods and cones. We found that in the Müller glia/astrocyte cluster, there was a significant increase in gene expression in pathways involving photoreceptor maintenance, while concomitant decreases were observed in rods and cones. Additionally, the expression of genes involved in mitochondrial localization and transport was increased in the Müller glia/astrocyte cluster. The Müller glial compensatory increase in the expression of genes downregulated in photoreceptors suggests that Müller glia adapt their transcriptome to support photoreceptors and could be thought of as general therapeutic targets to protect against retinal degeneration.

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Updates on the current treatments for diabetic retinopathy and possibility of future oral therapy

Tomita Y., Lee D., Tsubota K., Negishi K., Kurihara T.

Journal of Clinical Medicine （Journal of Clinical Medicine） 10 （ 20 ） 2021年10月

Diabetic retinopathy (DR) is a complication of diabetes and one of the leading causes of vision loss worldwide. Despite extensive efforts to reduce visual impairment, the prevalence of DR is still increasing. The initial pathophysiology of DR includes damage to vascular endothelial cells and loss of pericytes. Ensuing hypoxic responses trigger the expression of vascular endothelial growth factor (VEGF) and other pro-angiogenic factors. At present, the most effective treatment for DR and diabetic macular edema (DME) is the control of blood glucose levels. More advanced cases require laser, anti-VEGF therapy, steroid, and vitrectomy. Pan-retinal photocoagulation for non-proliferative diabetic retinopathy (NPDR) is well established and has demonstrated promising outcomes for preventing the progressive stage of DR. Furthermore, the efficacy of laser therapies such as grid and subthreshold diode laser micropulse photocoagulation (SDM) for DME has been re-ported. Vitrectomy has been performed for vitreous hemorrhage and tractional retinal detachment for patients with PDR. In addition, anti-VEGF treatment has been widely used for DME, and re-cently its potential to prevent the progression of PDR has been remarked. Even with these treat-ments, many patients with DR lose their vision and suffer from potential side effects. Thus, we need alternative treatments to address these limitations. In recent years, the relationship between DR, lipid metabolism, and inflammation has been featured. Research in diabetic animal models points to peroxisome proliferator-activated receptor alpha (PPARα) activation in cellular metabolism and inflammation by oral fenofibrate and/or pemafibrate as a promising target for DR. In this paper, we review the status of existing therapies, summarize PPARα activation therapies for DR, and discuss their potentials as promising DR treatments.

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論文 - 富田　洋平