Xin Jin

Third Military Medical University, Ch’ung-ch’ing-shih, Chongqing Shi, China

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Publications (9)39.31 Total impact

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    ABSTRACT: Oxidized LDL (oxLDL) induced vascular endothelial cell injury is a key event in the pathogenesis of atherosclerosis (AS). In our previous studies, we showed that delphinidin-3-glucoside (Dp), a natural anthocyanin, attenuated oxLDL-induced injury in human umbilical vein endothelial cells (HUVECs), indicating its potential role in preventing AS. However, the involved mechanism is not fully understood.
    Molecular Nutrition & Food Research 07/2014; · 4.31 Impact Factor
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    ABSTRACT: Inflammation participates centrally in all stages of atherosclerosis (AS), which begins with inflammatory changes in the endothelium, characterized by expression of the adhesion molecules. Resveratrol (RSV) is a naturally occurring phytoalexin that can attenuate endothelial inflammation; however, the exact mechanisms have not been thoroughly elucidated. Autophagy refers to the normal process of cell degradation of proteins and organelles, and is protective against certain inflammatory injuries. Thus, we intended to determine the role of autophagy in the antiinflammatory effects of RSV in human umbilical vein endothelial cells (HUVECs). We found that RSV pretreatment reduced tumor necrosis factor α (TNF/TNFα)-induced inflammation and increased MAP1LC3B2 (microtubule-associated protein 1 light chain 3 β 2) expression and SQSTM1/p62 (sequestosome 1) degradation in a concentration-dependent manner. A bafilomycin A 1 (BafA1) challenge resulted in further accumulation of MAP1LC3B2 in HUVECs. Furthermore, autophagy inhibitors 3-methyladenine (3-MA), chloroquine as well as ATG5 and BECN1 siRNA significantly attenuated RSV-induced autophagy, which, subsequently, suppressed the downregulation of RSV-induced inflammatory factors expression. RSV also increased cAMP (cyclic adenosine monophosphate) content, the expression of PRKA (protein kinase A) and SIRT1 (sirtuin 1), as well as the activity of AMPK (AMP-activated protein kinase). RSV-induced autophagy in HUVECs was abolished in the presence of inhibitors of ADCY (adenylyl cyclase, KH7), PRKA (H-89), AMPK (compound C), or SIRT1 (nicotinamide and EX-527), as well as ADCY, PRKA, AMPK, and SIRT1 siRNA transfection, indicating that the effects of RSV on autophagy induction were dependent on cAMP, PRKA, AMPK and SIRT1. In conclusion, RSV attenuates endothelial inflammation by inducing autophagy, and the autophagy in part was mediated through the activation of the cAMP-PRKA-AMPK-SIRT1 signaling pathway.
    Autophagy 09/2013; 9(12). · 12.04 Impact Factor
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    ABSTRACT: Resveratrol is a natural polyphenol that exerts potent effects to suppress atherosclerosis. However, its low concentration in plasma has placed this role in doubt. Thus, resveratrol effects might be dependent on its transport into vascular endothelium, a question not previously addressed in spite of its obvious and fundamental importance. Via high-performance liquid chromatography and liquid chromatography/mass spectrometry, we found that resveratrol was absorbed by human umbilical vein endothelial cells in a temperature-, concentration- and time-dependent manner, suggesting the involvement of passive diffusion and active transport. As determined by confocal laser scanning microscopy, resveratrol primarily distributed throughout the cytoplasm. Furthermore, resveratrol absorption was modulated by serum proteins and sodium-dependent glucose transporter 1 (SGLT1) yet inhibited by glucose (an SGLT1 substrate) and phlorizin (an SGLT1 selective inhibitor), as well as SGLT1 siRNA transfection. Additionally, Sprague-Dawley rats were intragastrically administrated with 100mg/kg of resveratrol and the concentration of resveratrol in blood vessels declined more slowly up to 24h compared to that in the blood. Our results suggested that resveratrol uptake by vascular endothelial cells involved both passive diffusion and an SGLT1-mediated process, at least partially. Moreover, the intracellular resveratrol pool may be more important than the serum level in vivo. These provide new insights into the cardiovascular benefits of resveratrol.
    The Journal of nutritional biochemistry 08/2013; · 4.29 Impact Factor
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    ABSTRACT: Delphinidin-3-glucoside (Dp) is a member of a family of bioactive compounds known as anthocyanins that occur naturally in pigmented plants and are known to ameliorate oxidative stress. Previous studies have showed that Dp decreased oxidative stress in vascular endothelial cells, however, the underlying mechanisms remain largely unknown. In the present study, we showed that pretreatment with Dp significantly suppressed oxidized low-density lipoprotein (oxLDL)-induced cell proliferation inhibition and apoptosis in primary human umbilical vein endothelial cells (HUVECs). Also, Dp pretreatment attenuated oxLDL-induced mitochondrial dysfunction via decreased reactive oxygen species (ROS) and superoxide anion generation, thereby repressing mitochondrial membrane potential and closing mitochondrial permeability transition pore. Furthermore, in vitro and in vivo data showed that Dp was transported into endothelial cells in a temperature, concentration, and time-dependent manner via the sodium-dependent glucose transporter (SGLT1). Suppression of SGLT1 by its substrate glucose, its inhibitor phlorizin or SGLT1 siRNA blocked Dp transportation. Repression of SGLT1 significantly inhibited Dp function of ameliorating mitochondrial dysfunction induced by pro-apoptotic factors (Apoptosis-inducing factor, Cytochrome c, Caspase-3 and Bax/Bcl-2 ratio). Taken together, our data indicate that Dp protects VECs via the SGLT1-ROS-mitochodria pathway. This new insight may help to elucidate the molecular mechanisms underlying the vascular protection afforded by Dp, and anthocyanins in general, in the context of prevention of endothelial dysfunction and atherosclerosis.
    PLoS ONE 01/2013; 8(7):e68617. · 3.73 Impact Factor
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    ABSTRACT: Increased intracellular reactive oxygen species (ROS) is crucial for vascular endothelial dysfunction, a key step in the initiating of atherosclerosis (AS). The antioxidant activity of flavonoids has been suggested to contribute to AS prevention. However, The association of the structure characteristics to antioxidant capacities in relation to the inhibitory effects on endothelial dysfunction has not been well established. In this study, four subclasses of flavonoids with similar structures, including two anthocyanins (delphinidin and cyanidin), two flavonols (myricetin and quercetin), two flavones (luteolin and apigenin) and two isoflavones (genistein and daidzein) were examined for their inhibitory effects on intracellular ROS-mediated signaling pathway in the human umbilical vein endothelial cell EA.hy926. Cells were pretreated with different flavonoids for 2 h and then exposed to oxLDL of 100 μg/ml for another 24 h. It was found that treatment with different flavonoids alone had no notable effects on cell viability. However, the oxLDL-induced decrease of cell viability, generation of O(2)(·-) and ROS, p38MAPK activation, NF-κB nuclear translocation, NF-κB-modulated transcriptional activity as well as the mRNA expression of genes including ICAM-1, VCAM-1, E-selectin, MMP-1, MMP-2 and MMP-9 were notably inhibited by the pretreatment of different flavonoids through blunting ROS-triggered signaling pathway, in spite of apparent differences. And the number of hydroxyl groups in total, 3',4'-ortho-dihydroxyl in B-ring and 3-hydroxyl group in C-ring of flavonoids were important structure characteristics for the inhibitory effects. Thus, anthocyanins and flavonols such as delphinidin and myricetin exert higher ROS scavenging activities and more significant endothelium-protective effects compared to the other compounds. Our results provide evidence for AS prevention and a basis for designing the potent anti-atherosclerotic agents.
    Biochimie 06/2012; 94(9):2035-44. · 3.14 Impact Factor
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    ABSTRACT: Monocyte adhesion to the vascular endothelium and their subsequent trans-endothelial migration are pivotal early events in atherogenesis. In this study, the effect of delphinidin, belonging to the group of anthocyanin, on adhesion of monocytes to endothelial cells induced by ox-LDL was investigated. The results showed that the pre-treatment with delphinidin (50, 100, or 200 μM) dose-dependently decreased the ox-LDL-induced up-regulation of the expression of ICAM-1 and P-selectin, and the enhanced adhesion and transmigration of monocytes. To determine the role of ROS/p38MAPK/NF-κB pathway, intracellular ROS level, p38MAPK protein expression, NF-κB transcription activity and protein expression, IκB-α degradation, NADPH oxidase subunit (Nox2 and p22phox) protein, and mRNA expression were measured. The results showed that delphinidin attenuated ox-LDL-induced generation of ROS, p38MAPK protein expression, NF-κB transcription activity and protein expression, IκB-α degradation, NADPH oxidase subunit (Nox2 and p22phox) protein and mRNA expression in endothelial cells in a dose-dependent manner. These results suggest that delphinidin attenuates ox-LDL induced expression of adhesion molecules (P-selectin and ICAM-1) and the adhesion of monocytes to endothelial cells by inhibiting ROS/p38MAPK/NF-κB pathway. These findings provide a basis for the design of potent antiatherosclerotic agents that will have therapeutic potential in the prevention of AS.
    Cell biochemistry and biophysics 06/2011; 61(2):337-48. · 3.34 Impact Factor
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    ABSTRACT: Vascular endothelial dysfunction induced by oxidative stress has been demonstrated to be the initiation step of atherosclerosis (AS), and flavonoids may play an important role in AS prevention and therapy. Twenty-three flavonoids categorized into flavones, flavonols, isoflavones, and flavanones, all with 4-oxo-pyronenucleus, were examined for what structural characteristics are required for the inhibitory effects on endothelial dysfunction induced by oxidized low-density lipoprotein (oxLDL). Human vascular endothelial cells EA.hy926 were pretreated with different 4-oxo-flavonoids for 2 hs, and then exposed to oxLDL for another 24 hs. Cell viability and the level of malondialdehyde (MDA), nitric oxide (NO) and soluble intercellular adhesion molecule-1 (sICAM-1) were measured, respectively. Then, correlation analysis and paired comparison were used to analyze the structure-activity relationships. Significant correlations were observed between the number of -OH moieties in total or in B-ring and the inhibitory effectson endothelial dysfunction. Furthermore, 3',4'-ortho-dihydroxyl on B-ring, 3-hydroxyl on C-ring and 2,3-double bondwere correlated closely to the inhibitory effects of flavonolson cell viability decrease and lipid peroxidation. 5,7-meta-dihydroxyl group on A-ring was crucial for the anti-inflammatory effects of flavones and isoflavones in endothelial cells. Moreover, the substituted position of B-ring on C3 rather than C2 was important for NO release. Additionally, hydroxylation at C6 position significantly attenuated the inhibitory effects of 4-oxo-flavonoids on endothelial dysfunction. Our findings indicated that the effective agents in inhibiting endothelial dysfunction include myricetin, quercetin, luteolin, apigenin, genistein and daidzein. Our work might provide some evidence for AS prevention and a strategy for the design of novel AS preventive agents.
    International Journal of Molecular Sciences 01/2011; 12(9):5471-5489. · 2.46 Impact Factor
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    ABSTRACT: Anthocyanins may play an important role in atherosclerosis prevention. However, the structure-function relationships are not well understood. The objective of this study was to compare the inhibitory effect of 21 anthocyanins against oxidized low-density lipoprotein-induced endothelial injury to understand the relationship between anthocyanin chemical structure and the endothelial protective properties, measured as cell viability, MDA production and NO release. Additionally, the intracellular anti-radical activity of the selected anthocyanins was investigated to identify the correlation with endothelial protection. Our results provide evidence that the number of -OH in total or in B-ring, 3',4'-ortho-dihydroxyl and 3-hydroxyl are the main structural requirements of anthocyanins in suppressing oxidative stress-induced endothelial injury and such inhibitory effect was significantly correlated with the intracellular radical scavenging activity.
    FEBS letters 12/2009; 584(3):583-90. · 3.54 Impact Factor
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    ABSTRACT: Moderate consumption of natural dietary polyphenolic compounds can reduce the risk of cardiovascular diseases. Here we investigated the protective effects of delphinidin against oxidized low-density lipoprotein (oxLDL)-induced damage in human umbilical vein endothelial cells (HUVECs). The MTT assay showed that 2h pre-incubation with delphinidin markedly restored the oxLDL-induced viability loss in HUVECs in a concentration-dependent manner. This effect was accompanied by a significant decrease in intracellular reactive oxygen species. Moreover, delphinidin imposed preventive effects on suppressing the production of lipid peroxidation, restoring the activities of endogenous antioxidants, and increasing the level of nitric oxide. Pre-incubation of delphinidin with HUVECs led to the reduction of apoptosis. Finally, delphinidin can efficiently prevent the down-regulation of Bcl-2 protein and up-regulation of Bax protein. Together, our findings suggest that delphinidin can effectively protect HUVECs against oxidative stress induced by oxLDL, which may be important for preventing both plaque development and stability in atherosclerosis.
    Chemico-biological interactions 10/2009; 183(1):105-12. · 2.46 Impact Factor