Apricot Melanoidins Prevent Oxidative Endothelial Cell Death by Counteracting Mitochondrial Oxidation and Membrane Depolarization

The cardiovascular benefits associated with diets rich in fruit and vegetables are thought to be due to phytochemicals contained in fresh plant material. However, whether processed plant foods provide the same benefits as unprocessed ones is an open question. Melanoidins from heat-processed apricots were isolated and their presence confirmed by colorimetric analysis and browning index. Oxidative injury of endothelial cells (ECs) is the key step for the onset and progression of cardiovascular diseases (CVD), therefore the potential protective effect of apricot melanoidins on hydrogen peroxide-induced oxidative mitochondrial damage and cell death was explored in human ECs. The redox state of cytoplasmic and mitochondrial compartments was detected by using the redox-sensitive, fluorescent protein (roGFP), while the mitochondrial membrane potential (MMP) was assessed with the fluorescent dye, JC-1. ECs exposure to hydrogen peroxide, dose-dependently induced mitochondrial and cytoplasmic oxidation. Additionally detected hydrogen peroxide-induced phenomena were MMP dissipation and ECs death. Pretreatment of ECs with apricot melanoidins, significantly counteracted and ultimately abolished hydrogen peroxide-induced intracellular oxidation, mitochondrial depolarization and cell death. In this regard, our current results clearly indicate that melanoidins derived from heat-processed apricots, protect human ECs against oxidative stress.     

丙型肝炎病毒核心蛋白对胞外基质金属蛋白酶诱导物基因转录的影响

目的：探讨丙型肝炎病毒（HCV）核心蛋白对胞外基质金属蛋白酶诱导物（EMMPRIN）基因转录的影响。方法：构建HCV核心蛋白真核表达载体和EMMPRIN启动子删除突变体pGL3载体,应用双萤光素酶报告基因系统检测EMMPRIN启动子不同删除突变体的转录活性,并寻找核心蛋白上调EMMPRIN转录相关的关键启动子区段。结果：HCV核心蛋白可以显著上调EMMPRIN的表达;调节EMMPRIN转录的启动子关键区段为＋1～435bp,HCV核心蛋白主要通过该关键区段上调EMMPRIN的转录,并呈现剂量依赖性。结论：HCV核心蛋白有可能通过EMMPRIN启动子关键区段上调EMMPRIN的转录,从而上调基质金属蛋白酶,最终导致肝癌转移。     

Expression of cell adhesion molecule T-cadherin in the human vasculature

Alterations in expression of surface adhesion molecules on resident vascular and blood-derived cells play a fundamental role in the pathogenesis of cardiovascular disease. Smooth muscle cells (SMCs) have been shown to express T-cadherin (T-cad), an unusual GPI-anchored member of the cadherin family of adhesion molecules. Particular relevance for T-cad in cardiovascular tissues is indicated by our present screen (immunoblotting) of human tissues and organs whereby highest expression of T-cad was found in aorta, carotid, iliac and renal arteries and heart. To explore the (patho)physiological role for T-cad in the vasculature we performed an immunohistochemical analysis of T-cad expression in normal human aorta and atherosclerotic lesions of varying severity. T-cad was present both in the intima and media and was expressed in endothelial cells (ECs), SMCs and pericytes, but not in monocytes/macrophages, foam cells and lymphocytes. In the adventitia T-cad was present in the wall of vasa vasorum and was expressed in ECs, SMCs and pericytes. T-cad was differentially expressed in SMCs from distinct vascular layers of normal aorta (for example, high in the subendothelial (proteoglycan) layer of the intima, low in the musculoelastic intimal layer and in the media), as well as at different stages of lesion progression. In SMCs there was an apparent inverse relationship between the intensities of T-cad and smooth muscle alpha-actin expression, this being most prominent in lesions. The findings suggest a phenotype-associated expression of T-cad which may be relevant to control of the normal vascular architecture and its remodelling during atherogenesis.     

Integrated investigation of lipidome and related signaling pathways uncovers molecular mechanisms of tetramethylpyrazine and butylidenephthalide protecting endothelial cells under oxidative stress

Tetramethylpyrazine (TMP) and butylidenephthalide (BP) are two bioactive components isolated from Ligusticum chuanxiong Hort and Angelica sinensis, respectively. These two traditional Chinese medicines have been widely used in clinical treatments for vascular disease. The mechanism by which TMP and BP protect endothelial cells (ECs) against oxidative stress remains unknown, as does their effects on the steady state of the lipidome of ECs. Here, we demonstrate that both compounds protect EA.hy926 cells against H(2)O(2) induced injury in a dose-dependent manner. We then apply an integrated analysis of the lipidome and signal transduction pathways to explore the underlying mechanism of their protective effects. We found that TMP elevates the content of several phosphatidylcholine (PC) species, reduces the release of arachidonic acid (AA) and inhibits the phosphorylation of cytosolic phospholipase A(2) (cPLA(2)). Compared to eicosatetraynoic acid (ETYA), a cPLA(2) inhibitor, TMP preferentially increases the content of arachidonoyl PCs. We also show that BP mainly elevates the pool of phosphatidylinositol (PI) species and inhibits the phosphorylation of both phospholipase C(γ) (PLC(γ)) and extracellular signal-regulated kinase 1/2 (ERK1/2). In contrast, specific inhibition of ERK1/2 by PD98059 decreases the cell viability and increases pool of phosphatidylserine (PS). Taken together, these results demonstrate that TMP protects oxidatively stressed ECs through inhibition of cPLA(2) and preferential increase of arachidonoyl PC levels. Conversely, the effects of BP are tied to inhibition of PLC(γ) and an increase in PI levels. The current work suggests that the interaction of the lipidome and phospholipases can serve as a promising therapeutic target in oxidatively stressed ECs.