Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oxidized LDL (oxLDL) has been implicated in the pathogenesis of atherosclerosis accompanying lipid-laden cell appearance, inflammatory responses, and vascular dysfunction. This study examined the potentials of polyphenol quercitrin to inhibit oxLDL induction of scavenger receptor A (SR-A) and CD36 involving activation of peroxisome proliferator-activated receptor gamma (PPARgamma). J774A1 murine macrophages were cultured with 10 microg/mL Cu(2+)-oxLDL for various times in the presence of 1-10 micromol/L quercitrin. Cu(2+)-oxLDL at the given concentration facilitated macrophage proliferation and enhanced oxLDL uptake. Quercitrin dampened oxLDL uptake and lipid accumulation elevated in macrophages exposed to oxLDL. Western blot analysis revealed that 10 microg/mL oxLDL upregulated expression of SR-A and CD36, which was rapidly abolished at the transcriptional levels by 10 micromol/L quercitrin within 4 h. Quercitrin diminished production of proinflammatory and proatherogenic vascular endothelial growth factor that augmented through the oxLDL binding to CD36. Similarly, quercitrin repressed expression of macrophage inflammatory protein-2 and monocyte chemoattractant protein-1 involved in monocyte trafficking and macropahage migration. In addition, quercitrin attenuated oxLDL-induced transcriptional activation of PPARgamma leading to CD36 induction. Furthermore, quercitrin alleviated macrophage uptake of oxLDL through interfering with PKC-PPAR signaling cascades. These results demonstrate that quercitrin blocked oxLDL uptake, cholesterol influx and lipid-laden foam cell formation through inhibiting induction of SR and VEGF linked to PKCalpha-PPARgamma-responsive pathways. Therefore, quercitrin may be an antiatherogenic agent blocking foam cell formation pertaining to induction of SR and VEGF.
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PMID:Dietary compound quercitrin dampens VEGF induction and PPARgamma activation in oxidized LDL-exposed murine macrophages: association with scavenger receptor CD36. 1992 18

Atherosclerosis is a disease resulting from impaired endothelial function, often caused by oxidant injury or inflammation. Endothelial progenitor cells (EPCs) play a critical role in repairing damaged endothelium and protecting against atherosclerosis. Quercitrin, a plant-derived flavonoid compound, displays antioxidant and anti-inflammatory activities. In this study, we showed that quercitrin treatment reduced the apoptosis of EPCs caused by oxidized low-density lipoprotein (ox-LDL) in a dose-dependent manner. Quercitrin improved tube formation, migration and adhesion of ox-LDL-treated EPCs. To determine the effect of quercitrin in vivo, EPCs treated with or without ox-LDL and quercitrin were locally injected into the ischemic hind limb muscle of nude mice. Those injected with EPCs treated with ox-LDL and quercitrin showed significantly increased local accumulation of EPCs, blood flow recovery and capillary density compared with the control and ox-LDL only groups. Furthermore, we showed that quercitrin enhanced autophagy and upregulated mitogen-activated protein kinase and ERK phosphorylation in a dose-dependent manner in vitro. Autophagy inhibitors, chloroquine and 3-methyladenine, abrogated quercitrin-enhanced autophagy caused by ox-LDL as evidenced by decreased numbers of branch points, migratory cells and adherent cells, and increased numbers of apoptotic cells. The ERK inhibitor PD98059 abrogated quercitrin-enhanced autophagy, as identified by decreased autophagosome formation and downregulated ERK phosphorylation. The inhibition of ERK did not affect the expression of Rac1, but enhanced phosphorylation of Akt. Quercitrin treatment also increased the expression of E-cadherin, and PD98059 abrogated the upregulation of E-cadherin induced by quercitrin. Our findings suggested that autophagy is a protective mechanism in EPCs exposed to oxidative damage. Quercitrin can promote autophagy through the activation of ERK and the ERK signaling pathway is therefore thought to play a pivotal role in mediating the protective effects on EPCs.
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PMID:Quercitrin treatment protects endothelial progenitor cells from oxidative damage via inducing autophagy through extracellular signal-regulated kinase. 2701 46