C1q/TNF-Related Protein 3 Prevents Diabetic Retinopathy via AMPK Dependent Stabilization of Blood-Retinal Barrier Tight Junctions

Abstract Background The impairment of the inner blood-retinal barrier (iBRB) increases the pathological development of diabetic retinopathy (DR), a severe complication in diabetic patients. Identifying approaches to preserving iBRB integrity and function is a major challenge in DR. C1q/tumor necrosis factor-related proteins-3 (CTRP3) is a newly discovered adipokine and an important biomarker predicting DR severity. We sought to determine whether and how CTRP3 affects the pathological development of non-proliferative diabetic retinopathy (NPDR). Methods To clarify the pathophysiologic progress of the blood-retinal barrier in NPDR and explore its potential mechanism, a mouse type 2 diabetic model of diabetic retinopathy was used. The capillary leakage was assessed by confocal microscope with fluorescent-labeled protein in vivo. Furthermore, the effect of CTRP3 on the inner blood-retinal barrier (iBRB) and its molecular mechanism was clarified. Results The results demonstrated that CTRP3 protects iBRB integrity and resists the vascular permeability induced by DR. Mechanistically, the administration of CTRP3 activates AMPK signaling pathway and enhances the expression of Occludin and Claudin-5 (tight junction protein) in vivo and in vitro. Meanwhile, CTRP3 improves the injury of human retinal endothelial cells (HRMECs) induced by high glucose/high lipids (HG/HL) and its protective effects are AMPK dependent. Conclusions In summary, we report for the first time that CTRP3 prevents diabetes-induced retinal vascular permeability via stabilizing the tight junctions of the iBRB and AMPK-dependent Occludin/Claudin-5 signaling pathway, thus critically affecting the development of NPDR.

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Protective effects of ginsenoside Rg1 on intestinal ischemia/reperfusion injury-induced oxidative stress and apoptosis via activation of the Wnt/β-catenin pathway

Scientific Reports ◽

10.1038/srep38480 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 27

Author(s):

Guo Zu ◽

Jing Guo ◽

Ningwei Che ◽

Tingting Zhou ◽

Xiangwen Zhang

Keyword(s):

Signaling Pathway ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Inflammatory Factors ◽

Therapeutic Effects ◽

Protective Effects ◽

Ginsenoside Rg1 ◽

Intestinal Ischemia Reperfusion

Abstract Ginsenoside Rg1 (Rg1) is one of the major bioactive ingredients in Panax ginseng, and it attenuates inflammation and apoptosis. The aims of our study were to explore the potential of Rg1 for the treatment of intestinal I/R injury and to determine whether the protective effects of Rg1 were exerted through the Wnt/β-catenin signaling pathway. In this study, Rg1 treatment ameliorated inflammatory factors, ROS and apoptosis that were induced by intestinal I/R injury. Cell viability was increased and cell apoptosis was decreased with Rg1 pretreatment following hypoxia/reoxygenation (H/R) in the in vitro study. Rg1 activated the Wnt/β-catenin signaling pathway in both the in vivo and in vitro models, and in the in vitro study, the activation was blocked by DKK1. Our study provides evidence that pretreatment with Rg1 significantly reduces ROS and apoptosis induced by intestinal I/R injury via activation of the Wnt/β-catenin pathway. Taken together, our results suggest that Rg1 could exert its therapeutic effects on intestinal I/R injury through the Wnt/β-catenin signaling pathway and provide a novel treatment modality for intestinal I/R injury.

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Tetrahydrocurcumin Ameliorates Diabetic Cardiomyopathy by Attenuating High Glucose-Induced Oxidative Stress and Fibrosis via Activating the SIRT1 Pathway

Oxidative Medicine and Cellular Longevity ◽

10.1155/2019/6746907 ◽

2019 ◽

Vol 2019 ◽

pp. 1-15 ◽

Cited By ~ 12

Author(s):

Kaifeng Li ◽

Mengen Zhai ◽

Liqing Jiang ◽

Fan Song ◽

Bin Zhang ◽

...

Keyword(s):

Oxidative Stress ◽

Signaling Pathway ◽

Diabetic Cardiomyopathy ◽

High Glucose ◽

Therapeutic Potential ◽

Ros Generation ◽

Protective Effects ◽

Collagen Iii

Hyperglycemia-induced oxidative stress and fibrosis play a crucial role in the development of diabetic cardiomyopathy (DCM). Tetrahydrocurcumin (THC), a major bioactive metabolite of natural antioxidant curcumin, is reported to exert even more effective antioxidative and superior antifibrotic properties as well as anti-inflammatory and antidiabetic abilities. This study was designed to investigate the potential protective effects of THC on experimental DCM and its underlying mechanisms, pointing to the role of high glucose-induced oxidative stress and interrelated fibrosis. In STZ-induced diabetic mice, oral administration of THC (120 mg/kg/d) for 12 weeks significantly improved the cardiac function and ameliorated myocardial fibrosis and cardiac hypertrophy, accompanied by reduced reactive oxygen species (ROS) generation. Mechanically, THC administration remarkably increased the expression of the SIRT1 signaling pathway both in vitro and in vivo, further evidenced by decreased downstream molecule Ac-SOD2 and enhanced deacetylated production SOD2, which finally strengthened antioxidative stress capacity proven by repaired activities of SOD and GSH-Px and reduced MDA production. Additionally, THC treatment accomplished its antifibrotic effect by depressing the ROS-induced TGFβ1/Smad3 signaling pathway followed by reduced expression of cardiac fibrotic markers α-SMA, collagen I, and collagen III. Collectively, these finds demonstrated the therapeutic potential of THC treatment to alleviate DCM mainly by attenuating hyperglycemia-induced oxidative stress and fibrosis via activating the SIRT1 pathway.

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Sodium Tanshinone IIA Silate Exerts Microcirculation Protective Effects against Spinal Cord Injury In Vitro and In Vivo

Oxidative Medicine and Cellular Longevity ◽

10.1155/2020/3949575 ◽

2020 ◽

Vol 2020 ◽

pp. 1-16

Author(s):

Xing Li ◽

Dan Luo ◽

Yu Hou ◽

Yonghui Hou ◽

Shudong Chen ◽

...

Keyword(s):

Spinal Cord ◽

Endothelial Cells ◽

Notch Signaling ◽

Signaling Pathway ◽

Notch Signaling Pathway ◽

Tanshinone Iia ◽

Protective Effects ◽

Cord Injury

Spinal cord microcirculation involves functioning endothelial cells at the blood spinal cord barrier (BSCB) and maintains normal functioning of spinal cord neurons, axons, and glial cells. Protection of both the function and integrity of endothelial cells as well as the prevention of BSCB disruption may be a strong strategy for the treatment of spinal cord injury (SCI) cases. Sodium Tanshinone IIA silate (STS) is used for the treatment of coronary heart disease and improves microcirculation. Whether STS exhibits protective effects for SCI microcirculation is not yet clear. The purpose of this study is to investigate the protective effects of STS on oxygen-glucose deprivation- (OGD-) induced injury of spinal cord endothelial cells (SCMECs) in vitro and to explore effects on BSCB and neurovascular protection in vivo. SCMECs were treated with various concentrations of STS (1 μM, 3 μM, and 10 μM) for 24 h with or without OGD-induction. Cell viability, tube formation, migration, and expression of Notch signaling pathway components were evaluated. Histopathological evaluation (H&E), Nissl staining, BSCB permeability, and the expression levels of von Willebrand Factor (vWF), CD31, NeuN, and Notch signaling pathway components were analyzed. STS was found to improve SCMEC functions and reduce inflammatory mediators after OGD. STS also relieved histopathological damage, increased zonula occludens-1 (ZO-1), inhibited BSCB permeability, rescued microvessels, protected motor neuromas, and improved functional recovery in a SCI model. Moreover, we uncovered that the Notch signaling pathway plays an important role during these processes. These results indicated that STS protects microcirculation in SCI, which may be used as a therapeutic strategy for SCI in the future.

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Protective Effects of Rice Peptide Oryza Peptide-P60 against Oxidative Injury through Activation of Nrf2 Signaling Pathway In Vitro and In Vivo

ACS Omega ◽

10.1021/acsomega.0c01016 ◽

2020 ◽

Vol 5 (22) ◽

pp. 13096-13107

Author(s):

Chie Moritani ◽

Kayoko Kawakami ◽

Hiroshi Shimoda ◽

Tadashi Hatanaka ◽

Etsuko Suzaki ◽

...

Keyword(s):

Signaling Pathway ◽

Oxidative Injury ◽

Protective Effects ◽

Nrf2 Signaling Pathway

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The Blood–Retinal Barrier in Retinal Disease

European Ophthalmic Review ◽

10.17925/eor.2009.03.02.105 ◽

2009 ◽

Vol 03 (02) ◽

pp. 105 ◽

Cited By ~ 11

Author(s):

José Cunha-Vaz ◽

Keyword(s):

Diabetic Retinopathy ◽

Tight Junctions ◽

Retinal Pigment ◽

Water Flux ◽

Retinal Disease ◽

Retinal Pigment Epithelial Cells ◽

Age Related Macular Degeneration ◽

Retinal Diseases ◽

Blood Retinal Barrier ◽

Age Related

The blood–ocular barrier system is formed by two main barriers: the blood–aqueous barrier and the blood–retinal barrier (BRB). The BRB is particularly tight and restrictive and is a physiological barrier that regulates ion, protein and water flux into and out of the retina. The BRB consists of inner and outer components, the inner BRB being formed of tight junctions between retinal capillary endothelial cells and the outer BRB of tight junctions between retinal pigment epithelial cells. The BRB is essential to maintaining the eye as a privileged site and is essential for normal visual function. Alterations of the BRB play a crucial role in the development of retinal diseases. The two most frequent and relevant retinal diseases, diabetic retinopathy and age-related macular degeneration (AMD), are directly associated with alterations of the BRB. Diabetic retinopathy is initiated by an alteration of the inner BRB and neovascular AMD is a result of an alteration of the outer BRB. Treatment of retinal diseases must also deal with the BRB either by using its specific transport mechanisms or by circumventing it through intravitreal injections

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Berberine Exerts a Protective Effect on Gut-Vascular Barrier via the Modulation of the Wnt/Beta-Catenin Signaling Pathway During Sepsis

Cellular Physiology and Biochemistry ◽

10.1159/000493412 ◽

2018 ◽

Vol 49 (4) ◽

pp. 1342-1351 ◽

Cited By ~ 8

Author(s):

Yan He ◽

Xiaoming Yuan ◽

Hao Zuo ◽

Ying Sun ◽

Aiwen Feng

Keyword(s):

Protective Effect ◽

Vascular Permeability ◽

Signaling Pathway ◽

Cecal Ligation ◽

Endothelial Permeability ◽

Bacterial Invasion ◽

Beta Catenin ◽

Endotoxin Level

Background/Aims: The gut-vascular barrier (GVB) has recently been depicted to dampen the bacterial invasion of the bloodstream. The intestinal mucosa is a tissue rich in small vessels including capillaries. In this study, the protective effect of berberine on GVB in small bowel mucosa was investigated. Methods: The rat cecal ligation and puncture (CLP) sepsis model was employed to evaluate the effect of berberine on serum endotoxin level and intestinal vascular permeability to Evans blue in vivo. The rat intestinal microvascular endothelial cells (RIMECs) treated by lipopolysaccharide (LPS) were used to assess the effect of berberine on endothelial permeability to FITC-labeled dextran, transendothelial electrical resistance (TEER), and tight junction (TJ) and adherens junction (AJ) expression in vitro. Results: After 24-hr CLP operation the serum endotoxin concentration and gut vascular permeability were significantly increased, while berberine markedly reduced endotoxin level and vascular leakage. In vitro, LPS not only dramatically increased endothelial permeability of RIMECs to FITC-dextran, but also decreased TEER and inhibited claudin-12, beta-catenin and VE-cadherin expression. These effects of LPS were antagonized by berberine. In addition, our in vivo and vitro studies also confirmed that the effect of berberine on GVB could be partially abolished by ICG001. Conclusion: Berberine exerted a protective effect on GVB function in sepsis, which was strictly related to the modulation of the Wnt/beta-catenin signaling pathway.

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Retinal Inflammation, Oxidative Stress, and Vascular Impairment Is Ablated in Diabetic Mice Receiving XMD8-92 Treatment

Frontiers in Pharmacology ◽

10.3389/fphar.2021.732630 ◽

2021 ◽

Vol 12 ◽

Author(s):

Scott J. Howell ◽

Chieh A. Lee ◽

Julia C. Batoki ◽

Thomas E. Zapadka ◽

Sarah I. Lindstrom ◽

...

Keyword(s):

Oxidative Stress ◽

Diabetic Retinopathy ◽

New Drugs ◽

Type I ◽

Type Ii ◽

Diabetic Mice ◽

Junction Protein ◽

Type Ii Diabetics ◽

Retinal Inflammation

The global number of diabetics continues to rise annually. As diabetes progresses, almost all of Type I and more than half of Type II diabetics develop diabetic retinopathy. Diabetic retinopathy is a microvascular disease of the retina, and is the leading cause of blindness in the working-age population worldwide. With such a significant health impact, new drugs are required to halt the blinding threat posed by this visual disorder. The cause of diabetic retinopathy is multifactorial, and an optimal therapeutic would halt inflammation, cease photoreceptor cell dysfunction, and ablate vascular impairment. XMD8-92 is a small molecule inhibitor that blocks inflammatory activity downstream of ERK5 (extracellular signal-related kinase 5) and BRD4 (bromodomain 4). ERK5 elicits inflammation, is increased in Type II diabetics, and plays a pathologic role in diabetic nephropathy, while BRD4 induces retinal inflammation and plays a role in retinal degeneration. Further, we provide evidence that suggests both pERK5 and BRD4 expression are increased in the retinas of our STZ (streptozotocin)-induced diabetic mice. Taken together, we hypothesized that XMD8-92 would be a good therapeutic candidate for diabetic retinopathy, and tested XMD8-92 in a murine model of diabetic retinopathy. In the current study, we developed an in vivo treatment regimen by administering one 100 μL subcutaneous injection of saline containing 20 μM of XMD8-92 weekly, to STZ-induced diabetic mice. XMD8-92 treatments significantly decreased diabetes-mediated retinal inflammation, VEGF production, and oxidative stress. Further, XMD8-92 halted the degradation of ZO-1 (zonula occludens-1), which is a tight junction protein associated with vascular permeability in the retina. Finally, XMD8-92 treatment ablated diabetes-mediated vascular leakage and capillary degeneration, which are the clinical hallmarks of non-proliferative diabetic retinopathy. Taken together, this study provides strong evidence that XMD8-92 could be a potentially novel therapeutic for diabetic retinopathy.

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Sitagliptin and the Blood-Retina Barrier: Effects on Retinal Endothelial Cells Manifested Only after Prolonged Exposure

Journal of Diabetes Research ◽

10.1155/2020/2450781 ◽

2020 ◽

Vol 2020 ◽

pp. 1-16

Author(s):

Anja Jäckle ◽

Focke Ziemssen ◽

Eva-Maria Kuhn ◽

Jürgen Kampmeier ◽

Gerhard K. Lang ◽

...

Keyword(s):

Extracellular Matrix ◽

Endothelial Cells ◽

Prolonged Exposure ◽

Diabetic Patients ◽

Barrier Dysfunction ◽

Fibronectin Receptor ◽

Retinal Endothelial Cells ◽

Junction Protein

Inhibitors of dipeptidyl peptidase-4 (DPP-4) are widely used to treat diabetes mellitus, but data concerning their effects on the barrier stability of retinal endothelial cells (REC) in vivo and in vitro are inconsistent. Therefore, we studied whether the barrier properties of immortalized endothelial cells of the bovine retina (iBREC) were affected by the inhibitors of DPP-4 sitagliptin (10-1000 nM) and diprotin A (1-25 μM). Their effects were also investigated in the presence of VEGF-A165 because diabetic patients often develop macular edema caused by VEGF-A-induced permeability of REC. To detect even transient or subtle changes of paracellular and transcellular flow as well as adhesion of the cells to the extracellular matrix, we continuously monitored the cell index (CI) of confluent iBREC grown on gold electrodes. Initially, the CI remained stable but started to decline significantly and persistently at 40 h or 55 h after addition of sitagliptin or diprotin A, respectively. Both inhibitors did not modulate, prevent, or revert the persistent VEGF-A165-induced reduction of the CI. Interestingly, sitagliptin and diprotin A increased the expression of the tight-junction protein claudin-1 which is an important component of a functional barrier formed by iBREC. In contrast, expressions of CD29—a subunit of the fibronectin receptor—or of the tetraspanin CD9 were lower after extended treatment with the DPP-4 inhibitors; less of the CD9 was seen at the plasma membrane after prolonged exposure to sitagliptin. Because both associated proteins are important for adhesion of iBREC to the extracellular matrix, the observed low CI might be caused by weakened attachment of the cells. From our results, we conclude that extended inhibition of DPP-4 destabilizes the barrier formed by microvascular REC and that DPP-4 inhibitors like sitagliptin do not counteract or enhance a VEGF-A165-induced barrier dysfunction as frequently observed in DME.

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DNMT1-mediated lncRNA MEG3 methylation accelerates endothelial-mesenchymal transition in diabetic retinopathy through the PI3K/AKT/mTOR signaling pathway

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00089.2020 ◽

2020 ◽

Author(s):

Yue He ◽

Yujiao Dan ◽

Xiaorong Gao ◽

Li Huang ◽

Hongbin Lv ◽

...

Keyword(s):

Diabetic Retinopathy ◽

Signaling Pathway ◽

Dna Methyltransferase ◽

Cell Model ◽

Mtor Signaling ◽

Diabetic Patients ◽

Cell Models ◽

Mtor Signaling Pathway ◽

Mesenchymal Transition ◽

Endothelial Mesenchymal Transition

Diabetic retinopathy (DR) is one of the serious complications that occur in diabetic patients that frequently causes blindness. Long non-coding RNAs (lncRNAs) have been associated with DR pathology. This study aimed to determine the underlying mechanism of lncRNA maternally expressed gene 3 (MEG3) in association with DNA methyltransferase 1 (DNMT1) in the endothelial-mesenchymal transition (endMT) that occurs in DR. A rat model of DR was induced by streptozotocin (STZ) injection, and high glucose (HG)-induced cell model was established by exposing microvascular endothelial cells obtained from retina of rats to HG. Subsequently, MEG3 was overexpressed in rat and cell models to characterize its impact on endMT in DR and the involvement of the PI3K/AKT/mTOR signaling pathway. Furthermore, the methylation level of MEG3 promoter region was determined with the application of methylation-specific polymerase chain reaction, followed by Chromatin immunoprecipitation assay for methyltransferase enrichment. Finally, we examined the regulation of DNMT1 on MEG3 methylation and endMT in the HG-induced cell model. The results obtained revealed downregulated MEG3 expression in DR rat and cell models. Overexpressed MEG3 was shown to suppress endMT in DR rat and cell models through the inhibition of the PI3K/AKT/mTOR signaling pathway. Notably, DNMT1 could promote MEG3 promoter methylation to inhibit MEG3 expression by recruiting methyltransferase, which activated the PI3K/AKT/mTOR signaling pathway to accelerate endMT in DR. These findings further highlighted the inhibitory effect of MEG3 on endMT in DR, thus presenting a novel therapeutic target candidate for DR treatment.

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Cannabinoid receptor 2 deletion deteriorates myocardial infarction through the down-regulation of AMPK-mTOR-p70S6K signaling-mediated autophagy

Bioscience Reports ◽

10.1042/bsr20180650 ◽

2019 ◽

Vol 39 (4) ◽

Cited By ~ 3

Author(s):

Yao Hu ◽

Yu Tao ◽

Jing Hu

Keyword(s):

Myocardial Infarction ◽

Cell Viability ◽

Signaling Pathway ◽

Cannabinoid Receptor ◽

Cell Counting ◽

Protective Effects ◽

Cannabinoid Receptor 2 ◽

Related Proteins

AbstractCannabinoid receptor 2 (CB2R) has been reported to play an important role in the regulation of pathogenesis and progression of myocardial infarction (MI). Here we tried to investigate its potential mechanisms. The ratio of infarct size in heart issue was detected by TTC staining, and cardiac functions were calculated according to echocardiographic evaluation. Cell viability in cardiomyocytes was investigated by Cell Counting Kit-8 (CCK-8) and lactate dehydrogenase (LDH) release assays. Western blot was used to detect autophagy-related proteins including Beclin-1, LC3, p62, adenosine 5′-monophosphate (AMP)-activated protein kinase (AMPK)-mammalian target of rapamycin rabbit (mTOR)-p70 ribosomal protein S6 kinase (p70S6K) signaling-related proteins including AMPK, mTOR, p70S6K, and their phosphorylation formation. Rapamycin was used for the induction of autophagy. Cleaved caspase-3 and Bax were detected for analyzing apoptosis. TEM was used for the detection of autophagosomes. We found that CB2R deletion (CB2R KO) largely deteriorated the severity of MI and the cardiac function as well as cell viability of cardiomyocytes. Knocking out CB2R decreased the level of autophagy in heart issues from MI mice as well as cardiomyocytes under oxygen-glucose deprivation (OGD). Furthermore, CB2R dysfunction significantly attenuated the cardiac protective effects of rapamycin both in vivo and in vitro. Finally, we found that CB2R-mediated autophagy was induced by AMPK-mTOR-p70S6K signaling pathway. Our current study demonstrated for the first time that CB2R deletion led to a detrimental effect of MI through the dysfunction of AMPK-mTOR-p70S6K signaling pathway, which might provide a novel insight in the treatment of MI.

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