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Tong J, Yao G, Chen Y, Xie H, Zheng X, Sun L, Huang Z, Xie Z. Mesenchymal Stem Cells Regulate Microglial Polarization via Inhibition of the HMGB1/TLR4 Signaling Pathway in Diabetic Retinopathy. Inflammation 2024:10.1007/s10753-024-02005-6. [PMID: 38625640 DOI: 10.1007/s10753-024-02005-6] [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: 01/05/2024] [Revised: 02/29/2024] [Accepted: 03/05/2024] [Indexed: 04/17/2024]
Abstract
Diabetic retinopathy (DR) is recognized as the most prevalent retinal degenerative disorder. Inflammatory response usually precedes microvascular alteration and is the primary factor of diabetic retinopathy. Activated microglia express many pro-inflammatory cytokines that exacerbate retina inflammation and disruption. In the present study, we found that MSCs alleviated blood-retina barrier (BRB) breakdown in diabetic rats, as evidenced by reduced retinal edema, decreased vascular leakage, and increased occludin expression. The MSC-treated retinal microglia exhibited reduced expression of M1-phenotype markers in the diabetic rats, including inducible nitric oxide synthase (iNOS), CD16, and pro-inflammatory cytokines. On the other hand, MSCs increased the expression of M2-phenotype markers, such as arginase-1 (Arg-1), CD206, and anti-inflammatory cytokines. HMGB1/TLR4 signaling pathway is activated in DR and inhibited after MSC treatment. Consistent with in vivo evidence, MSCs drove BV2 microglia toward M2 phenotype in vitro. Overexpression of HMGB1 in microglia reversed the effects of MSC treatment, suggesting HMGB1/TLR4 pathway is necessary for MSCs' regulatory effects on microglia polarization. Collectively, MSCs exert beneficial effects on DR by polarizing microglia from M1 toward M2 phenotype via inhibiting the HMGB1/TLR4 signaling pathway.
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Affiliation(s)
- Jun Tong
- Department of Ophthalmology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
- Department of Ophthalmology, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Genhong Yao
- Department of Rheumatology and Immunology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Yueqin Chen
- Department of Ophthalmology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Hairong Xie
- Department of Ophthalmology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Xinyu Zheng
- Department of Ophthalmology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Lingyun Sun
- Department of Rheumatology and Immunology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China.
| | - Zhenping Huang
- Department of Ophthalmology, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China.
| | - Zhenggao Xie
- Department of Ophthalmology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China.
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Hu A, Schmidt MHH, Heinig N. Microglia in retinal angiogenesis and diabetic retinopathy. Angiogenesis 2024:10.1007/s10456-024-09911-1. [PMID: 38564108 DOI: 10.1007/s10456-024-09911-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 02/18/2024] [Indexed: 04/04/2024]
Abstract
Diabetic retinopathy has a high probability of causing visual impairment or blindness throughout the disease progression and is characterized by the growth of new blood vessels in the retina at an advanced, proliferative stage. Microglia are a resident immune population in the central nervous system, known to play a crucial role in regulating retinal angiogenesis in both physiological and pathological conditions, including diabetic retinopathy. Physiologically, they are located close to blood vessels and are essential for forming new blood vessels (neovascularization). In diabetic retinopathy, microglia become widely activated, showing a distinct polarization phenotype that leads to their accumulation around neovascular tufts. These activated microglia induce pathogenic angiogenesis through the secretion of various angiogenic factors and by regulating the status of endothelial cells. Interestingly, some subtypes of microglia simultaneously promote the regression of neovascularization tufts and normal angiogenesis in neovascularization lesions. Modulating the state of microglial activation to ameliorate neovascularization thus appears as a promising potential therapeutic approach for managing diabetic retinopathy.
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Affiliation(s)
- Aiyan Hu
- Institute of Anatomy, Medical Faculty Carl Gustav Carus, Technische Universität Dresden School of Medicine, Fetscherstr 74, 01307, Dresden, Germany
| | - Mirko H H Schmidt
- Institute of Anatomy, Medical Faculty Carl Gustav Carus, Technische Universität Dresden School of Medicine, Fetscherstr 74, 01307, Dresden, Germany.
| | - Nora Heinig
- Institute of Anatomy, Medical Faculty Carl Gustav Carus, Technische Universität Dresden School of Medicine, Fetscherstr 74, 01307, Dresden, Germany.
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Chen J, Wang Q, Li R, Li Z, Jiang Q, Yan F, Ye J. The role of Keap1-Nrf2 signaling pathway during the progress and therapy of diabetic retinopathy. Life Sci 2024; 338:122386. [PMID: 38159594 DOI: 10.1016/j.lfs.2023.122386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 12/09/2023] [Accepted: 12/22/2023] [Indexed: 01/03/2024]
Abstract
Diabetic retinopathy is a complex and progressive ocular complication of diabetes mellitus and is a leading cause of blindness in people of working age worldwide. The pathophysiology of diabetic retinopathy involves multifactorial processes, including oxidative stress, inflammation and vascular abnormalities. Understanding the underlying molecular mechanisms involved in its pathogenesis is essential for the development of effective therapeutic interventions. One of the pathways receiving increasing attention is the Keap1-Nrf2 signaling pathway, which regulates the cellular response to oxidative stress by activating Nrf2. In this review, we analyze the current evidence linking Keap1-Nrf2 signaling pathway dysregulation to diabetic retinopathy. In addition, we explore the potential therapeutic implications and the challenges of targeting this pathway for disease management. A comprehensive understanding of the molecular mechanisms of diabetic retinopathy and the therapeutic potential of the Keap1-Nrf2 pathway may pave the way for innovative and effective interventions to combat this vision-threatening disease.
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Affiliation(s)
- Jiawen Chen
- State Key Laboratory of Natural Medicines, Research Center of Biostatistics and Computational Pharmacy, China Pharmaceutical University, Nanjing 211198, China; School of Life Science and Technology, China Pharmaceutical University, Nanjing 210006, China; Department of Ophthalmology, The First Affiliated Hospital of Yangtze University, Jingzhou, Hubei 434000, China
| | - Qi Wang
- Department of Ophthalmology, The First Affiliated Hospital of Yangtze University, Jingzhou, Hubei 434000, China
| | - Ruiyan Li
- School of Life Science and Technology, China Pharmaceutical University, Nanjing 210006, China
| | - Zhe Li
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China; Cardiovascular research Institute, Wuhan University, Wuhan 430060, China
| | - Qizhou Jiang
- School of Life Science and Technology, China Pharmaceutical University, Nanjing 210006, China
| | - Fangrong Yan
- State Key Laboratory of Natural Medicines, Research Center of Biostatistics and Computational Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
| | - Junmei Ye
- School of Life Science and Technology, China Pharmaceutical University, Nanjing 210006, China.
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Suzuki T, Sato T, Masuhara K, Tokusanai M, Akatsuka H, Kashikawa T, Suzuki Y. Trapa Bispinosa Roxb. Inhibits the Insulin-Dependent AKT/WNK1 Pathway to Induce Autophagy in Mice with Type 2 Diabetes. Diabetes Metab Syndr Obes 2023; 16:3095-3104. [PMID: 37818405 PMCID: PMC10561618 DOI: 10.2147/dmso.s430132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 10/04/2023] [Indexed: 10/12/2023] Open
Abstract
Purpose To elucidate the antiglycation activity of Trapa bispinosa Roxb. extract (TBE) and the related mechanism using a mouse model with type 2 diabetes. Materials and Methods We prepared control mice by giving them a normal diet, leptin-deficient ob/ob mouse (ob/ob mice) with a normal diet (normal ob/ob mice), and ob/ob mice with a diet containing TBE (TBE ob/ob mice). The effect of TBE on diabetic retina was evaluated by immunohistochemical staining and quantitative real-time polymerase chain reaction (qPCR) analysis. Results In both groups with ob/ob mice, body weight and hyperglycemia levels increased over time. Immunohistochemical staining analysis revealed that glial fibrillary acidic protein (GFAP) and advanced glycation end products (AGEs) expression levels were higher in normal ob/ob mice than in control mice, and lower in the TBE ob/ob mice than in normal ob/ob mice. Light chain-3 (LC-3) expression levels reduced in normal ob/ob mice compared to the control mice, but increased in TBE ob/ob mice compared to normal ob/ob mice. In the qPCR analysis, LC-3 expression levels were significantly lower in normal ob/ob mice compared to control mice, and significantly higher in TBE ob/ob mice compared to normal ob/ob mice. Conversely, AKT1 and with-no-lysine kinases 1 (WNK1) expression levels were significantly higher in normal ob/ob mice compared to control mice, and significantly lower in TBE ob/ob mice than in normal ob/ob mice. Conclusion In type 2 diabetes, it was suggested that TBE inhibits the insulin-dependent AKT/WNK1 pathway to induce autophagy, and thereby might promote anti-glycation and reduce retinal damage.
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Affiliation(s)
- Takahiro Suzuki
- Department of Ophthalmology, Tokai University School of Medicine, Kanagawa, Japan
| | - Takehito Sato
- Department of Immunology, Tokai University School of Medicine, Kanagawa, Japan
| | - Kaori Masuhara
- Department of Immunology, Tokai University School of Medicine, Kanagawa, Japan
| | - Mizuki Tokusanai
- Department of Immunology, Tokai University School of Medicine, Kanagawa, Japan
| | - Hisako Akatsuka
- Department of Immunology, Tokai University School of Medicine, Kanagawa, Japan
| | - Tomohiro Kashikawa
- Department of Immunology, Tokai University School of Medicine, Kanagawa, Japan
| | - Yasuyuki Suzuki
- Department of Ophthalmology, Tokai University School of Medicine, Kanagawa, Japan
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A Comprehensive Profiling of Cellular Sphingolipids in Mammalian Endothelial and Microglial Cells Cultured in Normal and High-Glucose Conditions. Cells 2022; 11:cells11193082. [PMID: 36231042 PMCID: PMC9563724 DOI: 10.3390/cells11193082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 09/20/2022] [Accepted: 09/23/2022] [Indexed: 11/17/2022] Open
Abstract
Sphingolipids (SPLs) play a diverse role in maintaining cellular homeostasis. Dysregulated SPL metabolism is associated with pathological changes in stressed and diseased cells. This study investigates differences in SPL metabolism between cultured human primary retinal endothelial (HREC) and murine microglial cells (BV2) in normal conditions (normal glucose, NG, 5 mM) and under high-glucose (HG, 25 mM)-induced stress by sphingolipidomics, immunohistochemistry, biochemical, and molecular assays. Measurable differences were observed in SPL profiles between HREC and BV2 cells. High-glucose treatment caused a >2.5-fold increase in the levels of Lactosyl-ceramide (LacCer) in HREC, but in BV2 cells, it induced Hexosyl-Ceramides (HexCer) by threefold and a significant increase in Sphingosine-1-phosphate (S1P) compared to NG. Altered SPL profiles coincided with changes in transcript levels of inflammatory and vascular permeability mediators in HREC and inflammatory mediators in BV2 cells. Differences in SPL profiles and differential responses to HG stress between endothelial and microglial cells suggest that SPL metabolism and signaling differ in mammalian cell types and, therefore, their pathological association with those cell types.
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Karimi R, Bakhshi A, Dayati P, Abazari O, Shahidi M, Savaee M, Kafi E, Rahmanian M, Naghib SM. Silymarin reduces retinal microvascular damage in streptozotocin-induced diabetic rats. Sci Rep 2022; 12:15872. [PMID: 36151457 PMCID: PMC9508129 DOI: 10.1038/s41598-022-20297-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Accepted: 09/12/2022] [Indexed: 11/29/2022] Open
Abstract
Diabetic retinopathy is a severe microvascular problem in diabetes mellitus. Silymarin is a flavonoid compound, and according to previous studies, it is a bioactive compound with potent antioxidant and anti-inflammatory properties. This investigation aims to peruse the impact of silymarin against diabetic retinopathy in streptozotocin (STZ)-provoked rats. Thirty-two adult male Wistar rats were randomly allocated into the control group, STZ group, STZ + silymarin (50 mg/kg), and STZ + silymarin (100 mg/kg). STZ rats received silymarin every day until 2 months after diabetes induction. The serum and retinal tissues were collected 2 months after silymarin treatment to determine biochemical and molecular analyses. Silymarin markedly lowered the serum glucose concentration in diabetic rats. Silymarin reduced the increased levels of advanced glycosylated end products (AGEs), the receptors for AGEs (RAGE), and reactive oxygen species (ROS) in diabetic rats. Silymarin also attenuated the phosphorylation of p38 MAP kinase and nuclear factor (NF)-κB p65 and diminished diabetes-induced overexpression of inflammatory cytokines, vascular endothelial growth factor (VEGF), adhesion molecules, and extracellular matrix proteins in STZ rats. Our data suggested that silymarin has protective effects against diabetic retinopathy, which might be related to the inhibition of the AGEs/RAGE axis and its antioxidant and anti-inflammatory activities.
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Affiliation(s)
- Rahman Karimi
- Department of Cell & Molecular Biology, Faculty of Biological Sciences, Kharazmi University, Tehran, Iran
| | - Ali Bakhshi
- Department of Clinical Biochemistry, School of Medicine, Shahid Sadoughi University of Medical Sciences and Health Services, Yazd, Iran
| | - Parisa Dayati
- Department of Clinical Biochemistry, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Omid Abazari
- Department of Clinical Biochemistry, School of Medicine, Shahid Sadoughi University of Medical Sciences and Health Services, Yazd, Iran
| | - Maryamsadat Shahidi
- Department of Clinical Biochemistry, School of Medicine, Shahid Sadoughi University of Medical Sciences and Health Services, Yazd, Iran
| | - Mohamadreza Savaee
- Department of Clinical Biochemistry, School of Medicine, Shahid Sadoughi University of Medical Sciences and Health Services, Yazd, Iran
| | - Ehsan Kafi
- Department of Clinical Biochemistry, School of Medicine, Shahid Sadoughi University of Medical Sciences and Health Services, Yazd, Iran
| | - Mehdi Rahmanian
- Biomaterials and Tissue Engineering Department, Breast Cancer Research Center, Motamed Cancer Institute, ACECR, Tehran, 1517964311, Iran
| | - Seyed Morteza Naghib
- Nanotechnology Department, School of Advanced Technologies, Iran University of Science and Technology (IUST), Tehran, Iran.
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7
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Mohamed MK, Atef AA, Moemen LA, Abdel Azeem AA, Mohalhal IA, Taha AM. Association study of HIF-1α rs11549465 and VEGF rs3025039 genetic variants with diabetic retinopathy in Egyptian patients: crosslinks with angiogenic, inflammatory, and anti-inflammatory markers. J Genet Eng Biotechnol 2022; 20:122. [PMID: 35969320 PMCID: PMC9378806 DOI: 10.1186/s43141-022-00401-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 07/14/2022] [Indexed: 11/10/2022]
Abstract
Background Genetic factors are implicated in the progression of DR—a global cause of blindness. Hence, the current work investigated the association of HIF-1α rs11549465 and VEGF rs3025039 genetic variants with the different stages of retinopathy among T2DM Egyptian patients. The crosslinks of these variants were explored with angiogenesis (VEGF), inflammation (AGEP and VCAM-1), and anti-inflammation (CTRP3) markers. Two hundred eighty-eight subjects were recruited in this study: 72 served as controls and 216 were having T2DM and were divided into diabetics without retinopathy (DWR), diabetics with non-proliferative retinopathy (NPDR), and diabetics with proliferative retinopathy (PDR). The genetic variants were analyzed using PCR-RFLP and their associations with NPDR and PDR were statistically tested. The circulating levels of AGEP, VCAM-1, HIF-1α, VEGF, and CTRP3 were assayed followed by analyzing their associations statistically with the studied variants. Results Only HIF-1α rs11549465 genetic variant (recessive model) was significantly associated with the development of NPDR among T2DM patients (p < 0.025) with a significant correlation with the circulating HIF-1α level (p < 0.0001). However, this variant was not associated with PDR progression. Neither HIF-1α rs11549465 nor VEGF rs3025039 genetic variants were associated with the PDR progression. The circulating AGEP, VCAM-1, HIF-1α, and VEGF were significantly elevated (p < 0.0001) while the CTRP3 was significantly decreased (p < 0.0001) in NPDR and PDR groups. The HIF-1α rs11549465 CT and/or TT genotype carriers were significantly associated with AGEP and VCAM-1 levels in the NPDR group, while it showed a significant association with the CTRP3 level in the PDR group. The VEGF rs3025039 TT genotype carriers showed only a significant association with the CTRP3 level in the PDR group. Conclusion The significant association of HIF-1α rs11549465 other than VEGF rs3025039 with the initiation of NPDR in T2DM Egyptian patients might protect them from progression to the proliferative stage via elevating circulating HIF-1α. However, this protective role was not enough to prevent the development of NPDR because of enhancing angiogenesis and inflammation together with suppressing anti-inflammation. The non-significant association of HIF-1α rs11549465 with PDR among T2DM patients could not make this variant a risk factor for PDR progression.
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Affiliation(s)
| | - Azza A Atef
- Department of Biochemistry, Faculty of Science, Ain Shams University, Cairo, Egypt
| | - Leqaa A Moemen
- Biochemistry Unit, Research Institute of Ophthalmology, Giza, Egypt
| | | | - Islam A Mohalhal
- Surgical Retina, Research Institute of Ophthalmology, Giza, Egypt
| | - Alshaimaa M Taha
- Department of Biochemistry, Faculty of Science, Ain Shams University, Cairo, Egypt.
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Advanced Glycations End Products in the Skin as Biomarkers of Cardiovascular Risk in Type 2 Diabetes. Int J Mol Sci 2022; 23:ijms23116234. [PMID: 35682915 PMCID: PMC9181586 DOI: 10.3390/ijms23116234] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 05/31/2022] [Accepted: 05/31/2022] [Indexed: 02/01/2023] Open
Abstract
The incidence and prevalence of diabetes are increasing worldwide, and cardiovascular disease (CVD) is the leading cause of death among subjects with type 2 diabetes (T2D). The assessment and stratification of cardiovascular risk in subjects with T2D is a challenge. Advanced glycation end products are heterogeneous molecules produced by non-enzymatic glycation of proteins, lipids, or nucleic acids. Accumulation of advanced glycation end products is increased in subjects with T2D and is considered to be one of the major pathogenic mechanism in developing complications in diabetes. Skin AGEs could be assessed by skin autofluorescence. This method has been validated and related to the presence of micro and macroangiopathy in individuals with type 2 diabetes. In this context, the aim of this review is to critically summarize current knowledge and scientific evidence on the relationship between skin AGEs and CVD in subjects with type 2 diabetes, with a brief reference to other diabetes-related complications.
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Chen Y, Xie T, Ye M, Lai Q, Wang Y, Xu Y, Chen W, Zheng W, Feng S, Huang Y. Combination of pathological and spectroscopic characterization to promote diagnosis of retinal pigment epithelium-Bruch's membrane complex in a diabetic rat model. BIOMEDICAL OPTICS EXPRESS 2021; 12:2221-2235. [PMID: 33996225 PMCID: PMC8086466 DOI: 10.1364/boe.419716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/13/2021] [Accepted: 03/15/2021] [Indexed: 05/04/2023]
Abstract
Diabetic retinopathy (DR) is a common condition of diabetes, and approaches to detecting early DR using the unique characteristics of the retinal pigment epithelium-Bruch's membrane complex (RBC) have increasingly attracted attention. A diabetic model was established in Sprague-Dawley rats via streptozocin (STZ) injection for 1 (DM1) and 6 months (DM6), confirmed by weekly blood glucose measurement. Serum and retinal tissue-based advanced glycation endproducts (AGE) levels significantly elevated in diabetic rats, and RBC was evaluated by transmission electron microscopy and Raman spectroscopy. The results showed that whole Raman spectra and all marked band intensities could respectively achieve almost equal and accurate discrimination of all animal groups, along with the determination of important molecules from the band data. Further quantitative analyses indicated series of metabolic disturbance due to hyperglycemia were involved while the body self-regulation mechanism still played a role with different effects during the disease progression. Given this, Raman spectroscopy can reliably distinguish the early characterization of DR in addition to providing intrinsic key molecules that is sensitive to identify the early disease progression.
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Affiliation(s)
- Yang Chen
- Department of Laboratory Medicine, Fujian Medical University, Fuzhou 350004, China
| | - Ting Xie
- Department of Ophthalmology & Optometry, Fujian Medical University, Fuzhou 350004, China
| | - Minlu Ye
- Department of Laboratory Medicine, Fujian Medical University, Fuzhou 350004, China
| | - Qiaoling Lai
- Department of Ophthalmology & Optometry, Fujian Medical University, Fuzhou 350004, China
| | - Yuting Wang
- Department of Laboratory Medicine, Fujian Medical University, Fuzhou 350004, China
| | - Yunchao Xu
- Key Laboratory of Optoelectronic Science and Technology for Medicine, Ministry of Education, Fujian Provincial Key Laboratory for Photonics Technology, Fujian Normal University, Fuzhou 350007, China
| | - Wenyi Chen
- Department of Ophthalmology & Optometry, Fujian Medical University, Fuzhou 350004, China
| | - Weidong Zheng
- Department of Ophthalmology, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350004, China
| | - Shangyuan Feng
- Key Laboratory of Optoelectronic Science and Technology for Medicine, Ministry of Education, Fujian Provincial Key Laboratory for Photonics Technology, Fujian Normal University, Fuzhou 350007, China
| | - Yan Huang
- Department of Ophthalmology & Optometry, Fujian Medical University, Fuzhou 350004, China
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10
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Mrugacz M, Bryl A, Zorena K. Retinal Vascular Endothelial Cell Dysfunction and Neuroretinal Degeneration in Diabetic Patients. J Clin Med 2021; 10:jcm10030458. [PMID: 33504108 PMCID: PMC7866162 DOI: 10.3390/jcm10030458] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 01/11/2021] [Accepted: 01/19/2021] [Indexed: 12/13/2022] Open
Abstract
Diabetes mellitus (DM) has become a vital societal problem as epidemiological studies demonstrate the increasing incidence of type 1 and type 2 diabetes. Lesions observed in the retina in the course of diabetes, referred to as diabetic retinopathy (DR), are caused by vascular abnormalities and are ischemic in nature. Vascular lesions in diabetes pertain to small vessels (microangiopathy) and involve precapillary arterioles, capillaries and small veins. Pericyte loss, thickening of the basement membrane, and damage and proliferation of endothelial cells are observed. Endothelial cells (monolayer squamous epithelium) form the smooth internal vascular lining indispensable for normal blood flow. Breaking its continuity initiates blood coagulation at that site. The endothelium controls the process of exchange of chemical substances (nutritional, regulatory, waste products) between blood and the retina, and blood cell passing through the vascular wall. Endothelial cells produce biologically active substances involved in blood coagulation, regulating vascular wall tension and stimulating neoangiogenesis. On the other hand, recent studies have demonstrated that diabetic retinopathy may be not only a microvascular disease, but is a result of neuroretinal degeneration. Neuroretinal degeneration appears structurally, as neural apoptosis of amacrine and Muller cells, reactive gliosis, ganglion cell layer/inner plexiform (GCL) thickness, retinal thickness, and retinal nerve fiber layer thickness, and a reduction of the neuroretinal rim in minimum rim width (MRW) and functionally as an abnormal electroretinogram (ERG), dark adaptation, contrast sensitivity, color vision, and microperimetric test. The findings in early stages of diabetic retinopathy may precede microvascular changes of this disease. Furthermore, the article's objective is to characterize the factors and mechanisms conducive to microvascular changes and neuroretinal apoptosis in diabetic retinopathy. Only when all the measures preventing vascular dysfunction are determined will the risk of complications in the course of diabetes be minimized.
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Affiliation(s)
- Malgorzata Mrugacz
- Department of Ophthalmology and Eye Rehabilitation, Medical University of Bialystok, 15-089 Białystok, Poland
| | - Anna Bryl
- Department of Ophthalmology and Eye Rehabilitation, Medical University of Bialystok, 15-089 Białystok, Poland
| | - Katarzyna Zorena
- Department of Immunobiology and Environment Microbiology, Medical University of Gdańsk, 18-211 Gdańsk, Poland
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Prantner D, Nallar S, Vogel SN. The role of RAGE in host pathology and crosstalk between RAGE and TLR4 in innate immune signal transduction pathways. FASEB J 2020; 34:15659-15674. [PMID: 33131091 DOI: 10.1096/fj.202002136r] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/07/2020] [Accepted: 10/13/2020] [Indexed: 12/15/2022]
Abstract
Although the innate immune receptor protein, Receptor for Advanced Glycation End products (RAGE), has been extensively studied, there has been renewed interest in RAGE for its potential role in sepsis, along with a host of other inflammatory diseases of chronic, noninfectious origin. In contrast to other innate immune receptors, for example, Toll-like receptors (TLRs), that recognize ligands derived from pathogenic organisms that are collectively known as "pathogen-associated molecular patterns" (PAMPs) or host-derived "damage-associated molecular patterns" (DAMPs), RAGE has been shown to recognize a broad collection of DAMPs exclusively. Historically, these DAMPs have been shown to be pro-inflammatory in nature. Early studies indicated that the adaptor molecule, MyD88, might be important for this change. More recent studies have explored further the mechanisms underlying this inflammatory change. Overall, the newer results have shown that there is extensive crosstalk between RAGE and TLRs. The three canonical RAGE ligands, Advanced Glycation End products (AGEs), HMGB1, and S100 proteins, have all been shown to activate both TLRs and RAGE to varying degrees in order to induce inflammation in in vitro models. As with any field that delves deeply into innate signaling, obstacles of reagent purity may be a cause of some of the discrepancies in the literature, and we have found that commercial antibodies that have been widely used exhibit a high degree of nonspecificity. Nonetheless, the weight of published evidence has led us to speculate that RAGE may be physically interacting with TLRs on the cell surface to elicit inflammation via MyD88-dependent signaling.
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Affiliation(s)
- Daniel Prantner
- Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Shreeram Nallar
- Institute of Human Virology, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Stefanie N Vogel
- Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, MD, USA
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12
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Gui F, You Z, Fu S, Wu H, Zhang Y. Endothelial Dysfunction in Diabetic Retinopathy. Front Endocrinol (Lausanne) 2020; 11:591. [PMID: 33013692 PMCID: PMC7499433 DOI: 10.3389/fendo.2020.00591] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 07/20/2020] [Indexed: 12/21/2022] Open
Abstract
Diabetic retinopathy (DR) is a diabetic complication which affects retinal function and results in severe loss of vision and relevant retinal diseases. Retinal vascular dysfunction caused by multifactors, such as advanced glycosylation end products and receptors, pro-inflammatory cytokines and chemokines, proliferator-activated receptor-γ disruption, growth factors, oxidative stress, and microRNA. These factors promote retinal endothelial dysfunction, which results in the development of DR. In this review, we summarize the contributors in the pathophysiology of DR for a better understanding of the molecular and cellular mechanism in the development of DR with a special emphasis on retinal endothelial dysfunction.
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