C1q/TNF–Related Protein-3 attenuates endothelial dysfunction in diabetic retinopathy via the Nitric Oxide signaling pathway

2020 ◽  
Author(s):  
Zheyi Yan ◽  
Xiaoming Cao ◽  
Chunfang Wang ◽  
Sha Liu ◽  
Lu Gan ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Cell Death ◽  
Diabetic Retinopathy ◽  
Endothelial Dysfunction ◽  
Signaling Pathway ◽  
Molecular Mechanisms ◽  
Apoptotic Cell ◽  
Related Protein

Abstract Background Diabetic retinopathy (DR) is a severe microvasculature complication of diabetes. Restoration of dysfunctional endothelial cells represents a promising approach to treatment of DR. It has been demonstrated that a number of CTRP (C1q/tumor necrosis factor-related protein) members improves vascular endothelial function of the aortic vasculature. However, the role of CTRPs in the treatment of DR remains largely unresolved. Therefore, the aim of this study was to determine whether members of the CTRP family improve diabetes-induced endothelial dysfunction of retinal vasculature, thus exhibiting a protective effect against diabetic injury of retina. Methods The vasoactivity of currently identified murine CTRP family members was assessed in vascular rings and the underlying molecular mechanisms elucidated in human retinal microvascular endothelial cells. We then mimicked diabetic retinopathy both in vitro and in vivo, after which they were treated with CTRP3, and the vasoactivity, apoptotic cell death and vascular leakage in the retina were evaluated. Discovery-drive approaches followed by cause-effect analysis were used to uncover the molecular mechanisms of CTRP3. Results Our results demonstrate that CTRP3, CTRP5, and CTRP9 exert vasorelaxant effects on macro- and micro-vessels, with CTRP3 being the most potent in micro-vessels. The effects of CTRP3 were found to be endothelium-dependent via the AdipoR1/AMPK/eNOS/Nitric Oxide (NO) pathway. In in vitro microvascular reactivity studies, CTRP3 successfully improved high glucose/high lipid-induced impairment of endothelium-dependent vasodilatation. Blockade of either AMPK or eNOS completely abolished the previously observed effects of CTRP3. In addition, in the murine diabetic retinopathy model, CTRP3 treatment increased endothelium-dependent relaxation and NO levels in microvessels, and inhibited apoptotic cell death and vascular leakage in the retina. Finally,blockade of NO synthesis completely abolished the effects of CTRP3 that had been measured previously. Conclusion Taken together, our findings reveal that the AdipoR1/AMPK/eNOS/NO signaling pathway, through which CTRP3 reverses endothelial dysfunction of the microvasculature by normalization of impaired vasodilatation, represents a novel intervention effective against diabetic injury of retina.

Interaction between NO and COX pathways in retinal cells exposed to elevated glucose and retina of diabetic rats

2004 ◽  
Vol 287 (4) ◽  
pp. R735-R741 ◽  
Author(s):  
Yunpeng Du ◽  
V. P. Sarthy ◽  
T. S. Kern
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Cell Death ◽  
Diabetic Retinopathy ◽  
Diabetic Rats ◽  
No Production ◽  
Retinal Cells ◽  
Elevated Glucose ◽  
Cox 2

A nonselective inhibitor of cyclooxygenase (COX; high-dose aspirin) and a relatively selective inhibitor of inducible nitric oxide synthase (iNOS; aminoguanidine) have been found to inhibit development of diabetic retinopathy in animals, raising a possibility that NOS and COX play important roles in the development of retinopathy. In this study, the effects of hyperglycemia on retinal nitric oxide (NO) production and the COX-2 pathway, and the interrelationship of the NOS and COX-2 pathways in retina and retinal cells, were investigated using a general inhibitor of NOS [ NG-nitro-l-arginine methyl ester (l-NAME)], specific inhibitors of iNOS [l- N6-(1-iminoethyl)lysine (l-NIL)] and COX-2 (NS-398), and aspirin and aminoguanidine. In vitro studies used a transformed retinal Müller (glial) cell line (rMC-1) and primary bovine retinal endothelial cells (BREC) incubated in 5 and 25 mM glucose with and without these inhibitors, and in vivo studies utilized retinas from experimentally diabetic rats (2 mo) treated or without aminoguanidine or aspirin. Retinal rMC-1 cells cultured in high glucose increased production of NO and prostaglandin E2 (PGE2) and expression of iNOS and COX-2. Inhibition of NO production with l-NAME or l-NIL inhibited all of these abnormalities, as did aminoguanidine and aspirin. In contrast, inhibition of COX-2 with NS-398 blocked PGE2 production but had no effect on NO or iNOS. In BREC, elevated glucose increased NO and PGE2 significantly, whereas expression of iNOS and COX-2 was unchanged. Viability of rMC-1 cells or BREC in 25 mM glucose was significantly less than at 5 mM glucose, and this cell death was inhibited by l-NAME or NS-398 in both cell types and also by l-NIL in rMC-1 cells. Retinal homogenates from diabetic animals produced significantly greater than normal amounts of NO and PGE2 and of iNOS and COX-2. Oral aminoguanidine and aspirin significantly inhibited all of these increases. The in vitro results suggest that the hyperglycemia-induced increase in NO in retinal Müller cells and endothelial cells increases production of cytotoxic prostaglandins via COX-2. iNOS seems to account for the increased production of NO in Müller cells but not in endothelial cells. We postulate that NOS and COX-2 act together to contribute to retinal cell death in diabetes and to the development of diabetic retinopathy and that inhibition of retinopathy by aminoguanidine or aspirin is due at least in part to inhibition of this NO/COX-2 axis.

scholarly journals Diabetic Endothelial Cells Differentiated From Patient iPSCs Show Dysregulated Glycine Homeostasis and Senescence Associated Phenotypes

2021 ◽  
Vol 9 ◽  
Author(s):  
Liping Su ◽  
Xiaocen Kong ◽  
Sze Jie Loo ◽  
Yu Gao ◽  
Jean-Paul Kovalik ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Dysfunction ◽  
Pluripotent Stem Cells ◽  
Molecular Mechanisms ◽  
Cell Transfer ◽  
Angiogenic Potential ◽  
Patients With Diabetes ◽  
Induced Pluripotent

Induced pluripotent stem cells derived cells (iPSCs) not only can be used for personalized cell transfer therapy, but also can be used for modeling diseases for drug screening and discovery in vitro. Although prior studies have characterized the function of rodent iPSCs derived endothelial cells (ECs) in diabetes or metabolic syndrome, feature phenotypes are largely unknown in hiPSC-ECs from patients with diabetes. Here, we used hiPSC lines from patients with type 2 diabetes mellitus (T2DM) and differentiated them into ECs (dia-hiPSC-ECs). We found that dia-hiPSC-ECs had disrupted glycine homeostasis, increased senescence, and impaired mitochondrial function and angiogenic potential as compared with healthy hiPSC-ECs. These signature phenotypes will be helpful to establish dia-hiPSC-ECs as models of endothelial dysfunction for understanding molecular mechanisms of disease and for identifying and testing new targets for the treatment of endothelial dysfunction in diabetes.

scholarly journals DEPTOR Deficiency-Mediated mTORc1 Hyperactivation in Vascular Endothelial Cells Promotes Angiogenesis

2018 ◽  
Vol 46 (2) ◽  
pp. 520-531 ◽  
Author(s):  
Yan Ding ◽  
Lanlan Shan ◽  
Wenqing Nai ◽  
Xiaojun Lin ◽  
Ling Zhou ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Signaling Pathway ◽  
Molecular Mechanisms ◽  
Gene Knockout ◽  
Umbilical Vein ◽  
Vascular Endothelial Cell ◽  
Tube Formation ◽  
Vascular Endothelial

Background/Aims: The mechanistic target of rapamycin (mTOR) signaling pathway is essential for angiogenesis and embryonic development. DEP domain-containing mTOR-interacting protein (DEPTOR) is an mTOR binding protein that functions to inhibit the mTOR pathway In vitro experiments suggest that DEPTOR is crucial for vascular endothelial cell (EC) activation and angiogenic responses. However, knowledge of the effects of DEPTOR on angiogenesis in vivo is limited. This study aimed to determine the role of DEPTOR in tissue angiogenesis and to elucidate the molecular mechanisms. Methods: Cre/loxP conditional gene knockout strategy was used to delete the Deptor gene in mouse vascular ECs. The expression or distribution of cluster of differentiation 31 (CD31), vascular endothelial growth factor (VEGF) and hypoxia inducible factor-1 alpha (HIF-1α) were detected by immunohistochemical staining or western blot. Tube formation assay was used to measure angiogenesis in vitro. Results: Deptor knockdown led to increased expression of CD31, VEGF and HIF-1α in heart, liver, kidney and aorta. After treatment with rapamycin, their expression was significantly down regulated. In vitro, human umbilical vein endothelial cells (HUVECs) were transfected with DEPTOR-specific small interfering RNA (siRNA), which resulted in a significant increase in endothelial tube formation and migration rates. In contrast, DEPTOR overexpression markedly reduced the expression of CD31, VEGF and HIF-1α. Conclusions: Our findings demonstrated that deletion of the Deptor gene in vascular ECs resulted in upregulated expression of CD31 and HIF-1α, and further stimulated the expression of VEGF which promoted angiogenesis, indicating that disruption of normal angiogenic pathways may occur through hyperactivation of the mTORC1/HIF-1α/VEGF signaling pathway.

scholarly journals Iron toxicity, lipid peroxidation and ferroptosis after intracerebral haemorrhage

2019 ◽  
Vol 4 (2) ◽  
pp. 93-95 ◽  
Author(s):  
Jieru Wan ◽  
Honglei Ren ◽  
Jian Wang
Keyword(s):  
Lipid Peroxidation ◽  
Cell Death ◽  
Intracerebral Haemorrhage ◽  
Neuronal Death ◽  
Molecular Mechanisms ◽  
Apoptotic Cell ◽  
Iron Toxicity ◽  
Secondary Brain Injury

Intracerebral haemorrhage (ICH) is a devastating type of stroke with high mortality and morbidity. However, we have few options for ICH therapy and limited knowledge about post-ICH neuronal death and related mechanisms. In the aftermath of ICH, iron overload within the perihaematomal region can induce lethal reactive oxygen species (ROS) production and lipid peroxidation, which contribute to secondary brain injury. Indeed, iron chelation therapy has shown efficacy in preclinical ICH studies. Recently, an iron-dependent form of non-apoptotic cell death known as ferroptosis was identified. It is characterised by an accumulation of iron-induced lipid ROS, which leads to intracellular oxidative stress. The ROS cause damage to nucleic acids, proteins and lipid membranes, and eventually cell death. Recently, we and others discovered that ferroptosis does occur after haemorrhagic stroke in vitro and in vivo and contributes to neuronal death. Inhibition of ferroptosis is beneficial in several in vivo and in vitro ICH conditions. This minireview summarises current research on iron toxicity, lipid peroxidation and ferroptosis in the pathomechanisms of ICH, the underlying molecular mechanisms of ferroptosis and the potential for combined therapeutic strategies. Understanding the role of ferroptosis after ICH will provide a vital foundation for cell death-based ICH treatment and prevention.

scholarly journals L-Arginine/Nitric Oxide Pathway and KCa Channels in Endothelial Cells: A Mini-Review

2020 ◽  
Author(s):  
Marcelo González ◽  
José Carlos Rivas
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Endothelial Function ◽  
Vascular Tone ◽  
Molecular Mechanisms ◽  
Cardiovascular Health ◽  
Kca Channels ◽  
Subsequent Activation ◽  
Regulation Of Vascular Tone

The endothelium is an organ with a key role in the maintenance of cardiovascular health through the regulation of vascular tone, vascular resistance, blood flow, and arterial pressure. These functions are related with the synthesis and release of vasoactive molecules, mainly vasodilators like nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF). Both factors are released and diffused from endothelial cells to the smooth muscle cells, where there is a subsequent activation of signaling pathways that finally decrease the intracellular calcium to induce the vascular relaxation. The study of the molecular mechanisms that underlie the endothelial function still is in development, but from the evidence obtained from the endothelial cells in vitro studies are possible to partially describe the pathways to regulate the physiological endothelial function and the disturbances in pathological conditions. In this mini-review, we describe the main mechanisms for NO synthesis and the role of potassium channels related with EDHF. We include schemes and graphical summaries for better understanding of the molecular regulation of vascular tone in the human cardiovascular system.

scholarly journals Upregulation of microRNA-876 Induces Endothelial Cell Apoptosis by Suppressing Bcl-Xl in Development of Atherosclerosis

2017 ◽  
Vol 42 (4) ◽  
pp. 1540-1549 ◽  
Author(s):  
Kaicheng Xu ◽  
Peng Liu ◽  
Yue Zhao
Keyword(s):  
Endothelial Cells ◽  
Cell Death ◽  
Endothelial Cell ◽  
Aortic Arch ◽  
Cell Apoptosis ◽  
Apoptotic Cell ◽  
Apoptotic Cell Death ◽  
Luciferase Reporter ◽  
Endothelial Cell Apoptosis

Background/Aims: The injury and apoptotic cell death of endothelial cells hallmark the development of atherosclerosis (AS), characterized by dysregulation of lipid homeostasis, immune responses, and formation of coronary plaques. However, the mechanisms underlying the initiation of endothelial cell apoptosis remain ill-defined. Recent evidence suggests a role of microRNAs in the processes of AS-associated endothelial cell apoptosis. Thus, we studied this question in the current study. Methods: AS was developed in ApoE (-/-) mice suppled with high-fat diet (HFD), compared to ApoE (-/-) mice suppled with normal diet (ND). Mouse endothelial cells were isolated from the aortic arch using flow cytometry based on their expression of Pecam-1. Oxidized low-density lipoprotein (ox-LDL) were used to treat human aortic endothelial cells (HAECs) as an in vitro model for AS. Gene expression was quantified by RT-qPCR and protein levels were analyzed by Western blotting. Apoptosis was evaluated by FITC Annexin V Apoptosis essay and by TUNEL staining. Prediction of the binding between miRNAs and 3'-UTR of mRNA from the target gene was performed by bioinformatics analyses and confirmed by a dual luciferase reporter assay. Results: HFD mice, but not ND mice, developed AS in 12 weeks. Significantly reduced endothelial cell marks and significantly increased mesenchymal cell marks were detected in the aortic arch of the HFD mice, compared to the ND mice. The endothelial cell apoptosis was significantly higher in HFD mice, seemingly due to functional suppression of protein translation of anti-apoptotic Bcl-Xl protein through upregulation of miR-876. Similar results were obtained from in vitro study. Inhibition of miR-876 abolished the effects of ox-LDL-induced apoptotic cell death of HAECs. Conclusion: AS-associated endothelial cell apoptosis may partially result from downregulation of Bcl-Xl, through upregulation of miR-876 that binds and suppresses translation of Bcl-Xl mRNA.

scholarly journals Cell Death and Ageing – A Question of Cell Type

2002 ◽  
Vol 2 ◽  
pp. 943-948 ◽  
Author(s):  
Pidder Jansen-Dürr
Keyword(s):  
Cell Death ◽  
Molecular Mechanisms ◽  
Replicative Senescence ◽  
Apoptotic Cell ◽  
Apoptotic Cell Death ◽  
Ageing Process ◽  
Human Ageing

Replicative senescence of human cells in primary culture is a widely accepted model for studying the molecular mechanisms of human ageing. The standard model used for studying human ageing consists of fibroblasts explanted from the skin and grown intoin vitrosenescence. From this model, we have learned much about molecular mechanisms underlying the human ageing process; however, the model presents clear limitations. In particular, a long-standing dogma holds that replicative senescence involves resistance to apoptosis, a belief that has led to considerable confusion concerning the role of apoptosis during human ageing. While there are data suggesting that apoptotic cell death plays a key role for ageingin vitroand in the pathogenesis of various age-associated diseases, this is not reflected in the current literature onin vitrosenescence. In this article, I summarize key findings concerning the relationship between apoptosis and ageingin vivoand also review the literature concerning the role of apoptosis during in vitro senescence. Recent experimental findings, summarized in this article, suggest that apoptotic cell death (and probably other forms of cell death) are important features of the ageing process that can also be recapitulated in tissue culture systems to some extent. Another important lesson to learn from these studies is that mechanisms ofin vivosenescence differ considerably between various histotypes.

scholarly journals Homoharringtonine inhibits fibroblasts proliferation, extracellular matrix production and reduces surgery-induced knee arthrofibrosis via PI3K/AKT/mTOR pathway-mediated apoptosis

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yu Sun ◽  
Jihang Dai ◽  
Rui Jiao ◽  
Qing Jiang ◽  
Jingcheng Wang
Keyword(s):  
Extracellular Matrix ◽  
Cell Death ◽  
Signaling Pathway ◽  
Apoptotic Cell ◽  
Dependent Manner ◽  
Potential Mechanism ◽  
Mtor Signaling Pathway ◽  
Extracellular Matrix Production ◽  
Matrix Production

Abstract Background The prevention of surgery-induced intraarticular fibrosis remains a challenge following orthopedic surgery. Homoharringtonine (HHT) has been reported to have positive effects in preventing various kinds of fibrosis. However, little is known regarding its effect as well as the potential mechanism of HHT in preventing surgery-induced intraarticular fibrosis. Methods Various concentrations of HHTs were locally applied in vivo to reduce knee intraarticular fibrosis in rabbits. Histological macroscopic assessments such as hematoxylin and eosin (HE) staining, Masson’s trichrome staining, and Picric-sirius red polarized light were used to evaluate the effect of HHT in reducing intraarticular fibrosis. CCK-8, cell cycle assay, and EdU incorporation assay were used in vitro to detect HHT’s effect on inhibiting fibroblast viability and proliferation. The effect of HHT on fibroblast differentiation, extracellular matrix production, and apoptosis were evaluated by western blot, flow cytometry, immunofluorescent staining, and TUNEL analysis. Moreover, the expressions of PI3K/AKT/mTOR signaling pathway were detected. Results The results demonstrated that HHT could reduce the formation of intraarticular fibrosis. HHT was also found to induce fibroblast apoptotic cell death in a dose- and time-dependent manner in vitro. Moreover, HHT could effectively inhibit the production of the extracellular matrix secreted by fibroblasts and inhibited the expression of p-PI3K, p-AKT, and p-mTOR in a dose-dependent manner. After treating with insulin-like growth factor-1 (IGF-1), an activator of the PI3K/AKT axis, the expressions of pro-apoptosis-related proteins were decreased, and the fibroblast apoptosis rate was also inhibited. Conclusions In conclusion, this study demonstrated that HHT could reduce the formation of intraarticular fibrosis through the inhibition of fibroblast proliferation, extracellular matrix production, and the induction of fibroblast apoptotic cell death. Furthermore, its potential mechanism may be through the suppression of the PI3K/AKT/mTOR signaling pathway.

scholarly journals The role of asymmetric dimethylarginine in the development of arterial hypertension.

2018 ◽  
Vol 95 (11) ◽  
pp. 965-970
Author(s):  
V. I. Podzolkov ◽  
T. A. Safronova ◽  
Dinara U. Natkina
Keyword(s):  
Endothelial Cells ◽  
Endothelial Dysfunction ◽  
Molecular Mechanisms ◽  
Asymmetric Dimethylarginine ◽  
Biological Marker ◽  
No Production ◽  
Nitric Oxide Synthase Inhibitor ◽  
Synthase Inhibitor

The results of numerous studies of recent decades confirm the crucial role of vascular endothelium in regulating vascular homeostasis. A plethora of recent studies have shed light on the clinical significance of endothelial dysfunction in essential hypertension. Asymmetric dimethylarginine (ADMA) is an endogenous nitric oxide synthase inhibitor. At present, it is considered as a generally recognized marker of endothelial dysfunction by most researchers. In vitro experiments showed that ADMA inhibits endothelium-dependent arterial relaxation, increases the level of indicators characterizing the degree of oxidative stress in endothelial cells, enhances the synthesis of the superoxide anion radical by endothelial cells. The molecular mechanisms described above, activated with an increase in the concentration of ADMA, cause various disturbances in the function of the cardiovascular system, which gave grounds to consider the level of ADMA as a criterion and risk factor for the development of cardiovascular diseases. Thus, ADMA plays a key role in the development and progression of CVD associated with a spectrum of diseases and pathological conditions characterized by a disturbance in NO production. Despite clinical and experimental confirmation of the relationship between the increase in ADMA in plasma and the development of cardiovascular events, the unambiguous etiopathogenetic role of ADMA in CVD requires further research. In order to accurately answer the question of whether ADMA is an etiological factor or a biological marker of CVD, additional analysis is needed to study the biochemical, genetic and pharmacological aspects of ADMA metabolism, the results of which are presented in this article.

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