Activation of sterol regulatory element binding protein and its involvement in endothelial cell migration / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the activation of sterol regulatory element binding protein (SREBP) and its critical role in endothelial cell migration.</p><p><b>METHODS</b>Bovine aortic endothelial cells (ECs) were cultured. The expression of SREBP and Cdc42 were determined by Western blot and quantitative real-time PCR. Moreover, outward growth migration model and transwell chamber assay were used to detect ECs migration.</p><p><b>RESULTS</b>(1) SREBP was activated during ECs migration. Western blot analysis demonstrated increased active form SREBP in migrating as compared to non-migrating ECs population. SREBP activation decreased as ECs migration slowed;(2) Coincidental with SREBP activation, mRNA expression of its target genes such as low density lipoprotein receptor, HMG-CoA reductase, and fatty acid synthase also increased in migrating ECs population as detected by real-time PCR; (3) Migration induced SREBP activation in ECs was inhibited by SREBP-acting protein RNAi and pharmacologically by 25-hydroxycholesterol; (4) Inhibition of SREBP led to decreased ECs migration in various models; (5) Cells genetically deficient in SREBP-acting protein, S1P, or S2P, phenotypically exhibited impaired migration; (6) SREBP inhibition in ECs suppressed the activity of small GTPase Cdc42, a key molecule for ECs motility.</p><p><b>CONCLUSIONS</b>SREBP is activated during and plays a critical role in ECs migration. Targeting SREBP could become a novel approach in fighting diseases involving abnormal ECs migration.</p>

A novel approach of proteomics to study the mechanism of action of grape seed proanthocyanidin extracts on diabetic retinopathy in rats / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Diabetic retinopathy (DR) is a leading cause of visual impairment and blindness among the people of occupational age. To prevent the progress of retina injury, effective therapies directed toward the key molecular target are required. Grape seed proanthocyanidin extracts (GSPE) have been reported to be effective in treating diabetic complications, while little is discussed about the functional protein changes.</p><p><b>METHODS</b>We used streptozotocin (STZ) to induce diabetes in rats. GSPE (250 mg/kg body weight per day) were administrated to diabetic rats for 24 weeks. Serum glucose, glycated hemoglobin and advanced glycation end products (AGEs) were determined. Consequently, 2-D difference gel electrophoresis and mass spectrometry were used to investigate retina protein profiles among control, STZ-induced diabetic rats, and GSPE treated diabetic rats.</p><p><b>RESULTS</b>GSPE significantly reduced the AGEs of diabetic rats (P < 0.05). Moreover, GSPE significantly suppressed the vascular lesions of central regions, decreased capillary enlargements and neovascularization, similar to those of the control rats under light microscope. Eighteen proteins were found either up-regulated or down-regulated in the retina of STZ-induced diabetic rats. And seven proteins in the retina of diabetic rats were found to be back-regulated to normal levels after GSPE therapy. These back-regulated proteins are involved in many important biological processes such as heat shock, ubiquitin-proteasome system, cell proliferation, cell growth and glucose metabolism.</p><p><b>CONCLUSIONS</b>These findings might promote a better understanding for the mechanism of DR, and provide novel targets for evaluating the effects of GSPE therapy.</p>