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Qin X, Zou H, Niu C. The STING pathway: An uncharacterized angle beneath the gut-retina axis. Exp Eye Res 2022; 217:108970. [PMID: 35114214 DOI: 10.1016/j.exer.2022.108970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 01/25/2022] [Accepted: 01/26/2022] [Indexed: 11/16/2022]
Abstract
The gut-retina axis is an emerging concept that describes a close interaction between the gut host-microbiota interface and the retina. Stimulator of interferon genes (STING) is a universally expressed adaptor protein localized in the endoplasmic reticulum. When activated by the cytosolic DNA sensor cyclic GMP-AMP synthase (cGAS), STING induces the activation of the transcription factor interferon regulatory factor 3 (IRF3) and nuclear factor-κB (NF-κB). Downstream effects include inflammation, autophagy, and programmed cell death. Dysregulation of the STING pathway has emerged as a crucial pathogenic mechanism underpinning a broad range of inflammatory diseases, autoimmune diseases, and cancer. Recently, a positive feedback loop between dysbiosis and aberrant activation of the intestinal STING pathway has been demonstrated, concurrently related to increased intestinal permeability. Alternations in the STING pathway have also been reported in the retina of patients with ocular diseases and retinal cells treated with pathological stimuli. Collectively, there is a chance that dysbiosis in patients with retinal diseases disrupts intestinal homeostasis and exacerbates barrier dysfunction through the erroneous accumulation of STING in the gut. Subsequent translocation of microbial products into the bloodstream allows access to the eye via the impaired blood-retina barrier, inducing the chronic activation of the STING pathway in the retina to participate in the disease progression. In this review, we explore how the alterations in the STING pathway could contribute to the gut disturbance and retinal pathologies and discuss its potential as a therapeutic target to treat the gut-retina axis-related diseases, which sheds some light on the better understanding of the crosstalk between the gut and retina.
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Affiliation(s)
- Xinran Qin
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Haidong Zou
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Eye Diseases Prevention & Treatment Center, Shanghai Eye Hospital, Shanghai, China; Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China; National Clinical Research Center for Eye Diseases, Shanghai, China; Shanghai Key Laboratory of Fundus Diseases, Shanghai, China.
| | - Chen Niu
- FosunLead Lingzhi Biomedical Technology Co. Ltd, Shanghai, China
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miR-223 Enhances the Neuroprotection of Estradiol Against Oxidative Stress Injury by Inhibiting the FOXO3/TXNIP Axis. Neurochem Res 2021; 47:1865-1877. [PMID: 34843004 DOI: 10.1007/s11064-021-03490-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 08/20/2021] [Accepted: 09/09/2021] [Indexed: 12/23/2022]
Abstract
Alzheimer's disease (AD) is an irreversible neurodegenerative disorder characterized by complex pathogenesis, of which oxidative stress has long been regarded as a major mechanism. Previously, the protective effects of estradiol on SH-SY5Y cells against Aβ42-induced injuries were demonstrated. In this study, the protection of SH-SY5Y cells by estradiol from H2O2-caused oxidative stress injury and Alzheimer's mice was further confirmed. H2O2 downregulated, whereas estradiol upregulated miR-223 expression. miR-223 overexpression promoted cell viability, inhibited cell apoptosis, reduced ROS levels, enhanced Superoxide Dismutase (SOD) activity, and decreased malondialdehyde (MDA) content. However, miR-223 inhibition exerted opposite effects. miR-223 directly targeted forkhead box O3 (FOXO3) and inhibited FOXO3 expression. H2O2 increased, whereas estradiol decreased thioredoxin interacting protein (TXNIP) levels; FOXO3 positively regulated TXNIP protein levels. In SH-SY5Y cells, FOXO3 overexpression increased, whereas FOXO3 knockdown reduced the cell apoptosis and ROS levels. FOXO3 bound to TXNIP promoter region and activated TXNIP transcription, whereas the activation could be partially inhibited by estradiol. Collectively, the FOXO3/TXNIP axis is downstream of miR-223. miR-223 enhances the neuroprotection of estradiol against oxidative stress injury through the FOXO3/TXNIP axis.
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Liu J, Tang M, Harkin K, Du X, Luo C, Chen M, Xu H. Single-cell RNA sequencing study of retinal immune regulators identified CD47 and CD59a expression in photoreceptors-Implications in subretinal immune regulation. J Neurosci Res 2020; 98:1498-1513. [PMID: 32166783 DOI: 10.1002/jnr.24618] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 02/21/2020] [Accepted: 02/29/2020] [Indexed: 12/29/2022]
Abstract
The neuroretina is protected by its own defense system, that is microglia and the complement system. Under normal physiological conditions, microglial activation is tightly regulated by the neurons although the underlying mechanism remains elusive. Using published single-cell RNA sequencing data sets, we found that immune regulatory molecules including CD200, CD47, CX3CL1, TGFβ, and complement inhibitor CD59a are expressed by various retinal neurons. Importantly, we found that photoreceptors express higher levels of CD47 and CD59a, which was further confirmed in cultured 661W cells, WERI-Rb1 cells, and microdissected photoreceptors from human eyes. The expression of CD59a mRNA in 661W cells was upregulated by TNFα and hypoxia, whereas LPS, hypoxia, and IL-4 upregulated CD47 mRNA expression in 661W cells. Immunofluorescence staining detected strong CD59a immunoreactivity in the outer nuclear layer, inner/outer segments, and discrete staining in ganglion cell layer (GCL), inner plexiform layer (IPL), and outer plexiform layer. The expression of CD59a in photoreceptors was increased in the detached retina, but decreased in retinas from experimental autoimmune uveoretinitis (EAU) mice. In EAU retina, CD59a was highly expressed by active immune cells. CD47 was detected in GCL, IPL, and inner nuclear layer and some photoreceptors. The expression of CD47 in photoreceptors was also increased in the detached retina but decreased in EAU retina. In a coculture system, 661W enhanced arginase-1 and reduced IL-6 mRNA expression in BV2 microglial cells. Our results suggest that photoreceptors express immune regulatory molecules and may have the potential to regulate immune activation in the outer retina/subretinal space under pathophysiological conditions.
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Affiliation(s)
- Jian Liu
- Aier Eye Institute, Aier School of Ophthalmology, Central South University, Changsha, P.R. China
| | - Miao Tang
- The Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, UK
| | - Kevin Harkin
- The Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, UK
| | - Xuan Du
- The Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, UK
| | - Chang Luo
- Aier Eye Institute, Aier School of Ophthalmology, Central South University, Changsha, P.R. China
| | - Mei Chen
- The Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, UK
| | - Heping Xu
- Aier Eye Institute, Aier School of Ophthalmology, Central South University, Changsha, P.R. China.,The Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, UK
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Vajaranant TS, Ray RM, Pasquale LR, Mares JA, Ritch R, Gower EW, Haan MN, Jackson RD, Maki PM. Racial Differences in the Effects of Hormone Therapy on Incident Open-Angle Glaucoma in a Randomized Trial. Am J Ophthalmol 2018; 195:110-120. [PMID: 30081016 DOI: 10.1016/j.ajo.2018.07.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Revised: 07/20/2018] [Accepted: 07/25/2018] [Indexed: 10/28/2022]
Abstract
PURPOSE We conducted a secondary analysis of a randomized, placebo-controlled trial to test if hormone therapy (HT) altered the risk of open-angle glaucoma (OAG), and if the risk reduction varied by race. DESIGN Secondary analysis of randomized controlled trial data. METHODS We linked Medicare claims data to 25 535 women in the Women's Health Initiative. Women without a uterus were randomized to receive either oral conjugated equine estrogens (CEE 0.625 mg/day) or placebo, and women with a uterus received oral CEE and medroxyprogesterone acetate (CEE 0.625 mg/day + MPA 2.5 mg/day) or placebo. We used Cox proportional hazards models to calculate hazard ratios (HR) and 95% confidence interval. RESULTS After exclusion of women with prevalent glaucoma or without claims for eye care provider visits, the final analysis included 8102 women (mean age = 68.5 ± 4.8 years). The OAG incidence was 7.6% (mean follow-up = 11.5 ± 5.2 years; mean HT duration = 4.4 ± 2.3 years). Increased age (P trend = .01) and African-American race (HR = 2.69, 95% CI = 2.13-3.42; white as a reference) were significant risk factors for incident OAG. We found no overall benefit of HT in reducing incident OAG (HR = 1.01, 95% CI = 0.79-1.29 in the CEE trial, and HR = 1.05, 95% CI = 0.85-1.29 in the CEE + MPA trial). However, race modified the relationship between CEE use and OAG risk (P interaction = .01), and risk was reduced in African-American women treated with CEE (HR = 0.49, 95% CI = 0.27-0.88), compared to placebo. Race did not modify the relation between CEE + MPA use and OAG risk (P interaction = .68). CONCLUSIONS Analysis suggests that HT containing estrogen, but not a combination of estrogen and progesterone, reduces the risk of incident OAG among African-American women. Further investigation is needed.
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Chaychi S, Polosa A, Chemtob S, Lachapelle P. Evaluating the neuroprotective effect of 17β-estradiol in rodent models of oxidative retinopathies. Doc Ophthalmol 2018; 137:151-168. [PMID: 30368631 DOI: 10.1007/s10633-018-9658-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 10/15/2018] [Indexed: 12/14/2022]
Abstract
PURPOSE To determine the neuroprotective effect of estrogen on the structure and function of the retina exposed to an oxidative stress. METHODS Male Sprague-Dawley rat pups were exposed to either hyperoxia (O2E: from P8 to P14) or bright light (LE: from P14 to P28) with or without 17 β-estradiol (βE2) treatment. Retinal structure (histology) and function (ERG) were assessed at selected time points. RESULTS In the O2E model, βE2 injections caused a significant reduction of the ERG and a significantly thinner OPL compared to untreated oxygen-exposed group (O2-exposed) rats. In contrast, in the LE model βE2, treatment was beneficial to the retinal structure (thicker ONL) and function (better preserved ERG amplitudes) compared to untreated light-exposed group (light-exposed rats). CONCLUSION Our results show that in conditions where the primary target of the oxidative stress is the outer retina (i.e., the photoreceptors) estrogen can protect the retina, while in situations where the inner retina (or retinal vasculature) is the main site of oxidative damage, estrogen may potentiate the detrimental effect of oxidative stress on the retina.
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Affiliation(s)
- Samaneh Chaychi
- Departments of Ophthalmology and Neurology-Neurosurgery, Faculty of Medicine, McGill University and Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Glen Site, Block E, Room EM03238, Montréal, QC, H4A 3J1, Canada
| | - Anna Polosa
- Departments of Ophthalmology and Neurology-Neurosurgery, Faculty of Medicine, McGill University and Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Glen Site, Block E, Room EM03238, Montréal, QC, H4A 3J1, Canada
| | - Sylvain Chemtob
- Departments of Pediatrics, Ophthalmology, and Pharmacology, Centre Hospitalier Universitaire Ste-Justine Research Center, Montréal, QC, Canada
| | - Pierre Lachapelle
- Departments of Ophthalmology and Neurology-Neurosurgery, Faculty of Medicine, McGill University and Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Glen Site, Block E, Room EM03238, Montréal, QC, H4A 3J1, Canada.
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Ogasawara S, Cheng XW, Inoue A, Hu L, Piao L, Yu C, Goto H, Xu W, Zhao G, Lei Y, Yang G, Kimura K, Umegaki H, Shi GP, Kuzuya M. Cathepsin K activity controls cardiotoxin-induced skeletal muscle repair in mice. J Cachexia Sarcopenia Muscle 2018; 9:160-175. [PMID: 29058826 PMCID: PMC5803616 DOI: 10.1002/jcsm.12248] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 08/30/2017] [Accepted: 09/05/2017] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Cathepsin K (CatK) is a widely expressed cysteine protease that has gained attention because of its enzymatic and non-enzymatic functions in signalling. Here, we examined whether CatK-deficiency (CatK-/- ) would mitigate injury-related skeletal muscle remodelling and fibrosis in mice, with a special focus on inflammation and muscle cell apoptosis. METHODS Cardiotoxin (CTX, 20 μM/200 μL) was injected into the left gastrocnemius muscle of male wild-type (CatK+/+ ) and CatK-/- mice, and the mice were processed for morphological and biochemical studies. RESULTS On post-injection Day 14, CatK deletion ameliorated muscle interstitial fibrosis and remodelling and performance. At an early time point (Day 3), CatK-/- reduced the lesion macrophage and leucocyte contents and cell apoptosis, the mRNA levels of monocyte chemoattractant protein-1, toll-like receptor-2 and toll-like receptor-4, and the gelatinolytic activity related to matrix metalloproteinase-2/-9. CatK deletion also restored the protein levels of caspase-3 and cleaved caspase-8 and the ratio of the BAX to the Bcl-2. Moreover, CatK deficiency protected muscle fibre laminin and desmin disorder in response to CTX injury. These beneficial muscle effects were mimicked by CatK-specific inhibitor treatment. In vitro experiments demonstrated that pharmacological CatK inhibition reduced the apoptosis of C2C12 mouse myoblasts and the levels of BAX and caspase-3 proteins induced by CTX. CONCLUSIONS These results demonstrate that CatK plays an essential role in skeletal muscle loss and fibrosis in response to CTX injury, possibly via a reduction of inflammation and cell apoptosis, suggesting a novel therapeutic strategy for the control of skeletal muscle diseases by regulating CatK activity.
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Affiliation(s)
- Shinyu Ogasawara
- Department of Community Healthcare & Geriatrics, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Aichiken, Japan
| | - Xian Wu Cheng
- Department of Community Healthcare & Geriatrics, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Aichiken, Japan.,Institute of Innovation for Future Society, Nagoya University, Nagoya, 464-0814, Aichiken, Japan.,Department of Cardiology and ICU, Yanbian University Hospital, Yanji, 133000, Jilin, China.,Department of Internal Medicine, Kyung Hee University, Seoul, 130-702, Korea
| | - Aiko Inoue
- Department of Community Healthcare & Geriatrics, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Aichiken, Japan.,Institute of Innovation for Future Society, Nagoya University, Nagoya, 464-0814, Aichiken, Japan
| | - Lina Hu
- Department of Community Healthcare & Geriatrics, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Aichiken, Japan.,Department of Public Health, Guilin Medical College, Guilin, 541004, Guangxi, China
| | - Limei Piao
- Department of Community Healthcare & Geriatrics, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Aichiken, Japan.,Department of Cardiology and ICU, Yanbian University Hospital, Yanji, 133000, Jilin, China
| | - Chenglin Yu
- Department of Community Healthcare & Geriatrics, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Aichiken, Japan.,Department of Cardiology and ICU, Yanbian University Hospital, Yanji, 133000, Jilin, China
| | - Hiroki Goto
- Department of Community Healthcare & Geriatrics, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Aichiken, Japan
| | - Wenhu Xu
- Department of Community Healthcare & Geriatrics, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Aichiken, Japan.,Department of Cardiology and ICU, Yanbian University Hospital, Yanji, 133000, Jilin, China
| | - Guangxian Zhao
- Department of Community Healthcare & Geriatrics, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Aichiken, Japan.,Department of Cardiology and ICU, Yanbian University Hospital, Yanji, 133000, Jilin, China
| | - Yanna Lei
- Department of Community Healthcare & Geriatrics, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Aichiken, Japan.,Department of Cardiology and ICU, Yanbian University Hospital, Yanji, 133000, Jilin, China
| | - Guang Yang
- Department of Community Healthcare & Geriatrics, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Aichiken, Japan.,Department of Cardiology and ICU, Yanbian University Hospital, Yanji, 133000, Jilin, China
| | - Kaoru Kimura
- Department of Community Healthcare & Geriatrics, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Aichiken, Japan
| | - Hiroyuki Umegaki
- Department of Community Healthcare & Geriatrics, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Aichiken, Japan
| | - Guo-Ping Shi
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 20115, USA
| | - Masafumi Kuzuya
- Department of Community Healthcare & Geriatrics, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Aichiken, Japan.,Institute of Innovation for Future Society, Nagoya University, Nagoya, 464-0814, Aichiken, Japan
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