Autophagy protects macrophages from oxidized low-density lipoprotein-induced apoptosis by inhibiting C/EBP homologous protein expression

AIM: To investigate the protective effect of autophagy on oxidized low density lipoprotein (ox-LDL)-induced macrophage apoptosis and the underlying molecular mechanisms. METHODS: The RAW264.7 macrophages were pretreated with 3 mmol/L 3-methyladenine (3-MA), 1 μmol/L rapamycin (Rap) or 4 mmol/L 4-phenylbutyric acid (PBA) respectively for 1 h and then treated with ox-LDL (100 mg/L) for 12 h. The cell viability and apoptosis were determined by MTT assay and flow cytometry with Annexin V-FITC/PI staining, respectively. The activities of lactate dehydrogenase (LDH) in the medium and caspase-3 in the cells were determined by detection kits. The protein levels of beclin-1 (a molecular marker of autophagy), glucose-regulated protein 78 (GRP78, an endoplasmic reticulum stress marker) and C/EBP homologous protein (CHOP, a key-signaling component of endoplasmic reticulum stress-induced apoptosis) were examined by Western blot. Microtubule-associated protein 1 light chain 3 (LC3, another molecular marker of autophagy) was observed under laser scanning confocal microscope.RESULTS: Treatment of the RAW264.7 macrophages with ox-LDL at 100 mg/L for 12 h resulted in significant decrease in cell viability, and dramatic elevation in LDH leakage, cell apoptosis and caspase-3 activity, which were promoted by 3-MA (an autophagy inhibitor) and inhibited by Rap (an autophagy inducer). ox-LDL induced autophagy in the macrophages as assessed by beclin-1 upregulation and frequent granulation of LC3, which were inhibited by 3-MA and promoted by Rap. Interestingly, 3-MA enhanced, while Rap blocked, the CHOP upregulation induced by ox-LDL. Moreover, PBA (endoplasmic reticulum stress inhibitor) significantly inhibited ox-LDL-induced GRP78 upregulation and autophagy as determined by the attenuation of beclin-1 upregulation and frequent granulation of LC3. CONCLUSION: Endoplasmic reticulum stress mediates ox-LDL-induced autophagy in macrophages, and moderates activation of autophagy may protect macrophages from ox-LDL-induced apoptosis by inhibiting CHOP expression.     

Impact of hyperlipidaemia on intermediary metabolism,faecal microbial metabolites and urinary characteristics of lipoprotein lipase deficient vs. normal cats

Findings in humans and rats indicate that hyperlipidaemia may be associated with enhanced endogenous oxalate (Ox) synthesis, which may be relevant for calcium oxalate (CaOx) urolith formation. Moreover, changes in lipid metabolism are proposed to negatively affect gut microbiota. This study aimed to investigate those potential interactions in hyperlipidaemic cats. Therefore, 10 normal control cats and seven lipoprotein lipase (LPL)‐deficient cats were fed a low‐fat diet for seven weeks. During the last week of the study, cats were housed in metabolic cages to collect urine and faeces. Blood was taken on the last day of the study. The LPL‐deficient cats had significantly higher serum triglyceride concentrations than normal cats, while lactate dehydrogenase (LDH) activity was not different. Urinary relative supersaturation with CaOx, urinary Ox, calcium, and citrate excretions, and urine pH did not differ between groups. Lower faecal acetic, propionic and total short‐chain fatty acid concentrations were observed in the LPL‐deficient cats. In conclusion, hyperlipidaemia does not appear to be a specific risk factor for CaOx urolith formation in cats. In contrast to results in rats, hyperlipidaemia was not accompanied by elevated serum LDH activity. As LDH can synthesise Ox from glycolate or other precursors, this might be one possible explanation for the similar urinary parameters in the LPL‐deficient and normal cats. Non‐diet‐induced hyperlipidaemia was not associated with marked changes in faecal microbial metabolites, suggesting no differences in the composition of the intestinal microbiota.     

性早熟前后中华绒螯蟹血淋巴中总蛋白和高密度脂蛋白水平的比较

研究发现,在进入卵巢快速发育期后,斑节对虾(Penaeus monodon)卵巢中甘油三脂(TG)、磷脂酰乙醇胺(PE)和磷脂酰胆碱(PC)含量都有所升高,而与此同时,肝胰腺中的脂类(主要是TG及PC)含量却下降[1]。这说明,在卵母细胞发育期间,肝胰腺中有一部分脂类转运到了卵巢。由于脂类不溶于水,     

Protective Effect of Flavonoids from a Deep-Sea-Derived Arthrinium sp. against ox-LDL-Induced Oxidative Injury through Activating the AKT/Nrf2/HO-1 Pathway in Vascular Endothelial Cells

Oxidized low-density lipoprotein (ox-LDL)-induced oxidative injury in vascular endothelial cells is crucial for the progression of cardiovascular diseases, including atherosclerosis. Several flavonoids have been shown cardiovascular protective effects. Recently, our research group confirmed that the novel flavonoids isolated from the deep-sea-derived fungus Arthrinium sp., 2,3,4,6,8-pentahydroxy-1-methylxanthone (compound 1) and arthone C (compound 2) effectively scavenged ROS in vitro. In this study, we further investigated whether these compounds could protect against ox-LDL-induced oxidative injury in endothelial cells and the underlying mechanisms. Our results showed that compounds 1 and 2 inhibited ox-LDL-induced apoptosis and adhesion factors expression in human umbilical vein vascular endothelial cells (HUVECs). Mechanistic studies showed that these compounds significantly inhibited the ROS level increase and the NF-κB nuclear translocation induced by ox-LDL. Moreover, compounds 1 and 2 activated the Nrf2 to transfer into nuclei and increased the expression of its downstream antioxidant gene HO-1 by inducing the phosphorylation of AKT in HUVECs. Importantly, the AKT inhibitor MK-2206 2HCl or knockdown of Nrf2 by RNA interference attenuated the inhibition effects of these compounds on ox-LDL-induced apoptosis in HUVECs. Meanwhile, knockdown of Nrf2 abolished the effects of the compounds on ox-LDL-induced ROS level increase and the translocation of NF-κB to nuclei. Collectively, the data showed that compounds 1 and 2 protected endothelial cells against ox-LDL-induced oxidative stress through activating the AKT/Nrf2/HO-1 pathway. Our study provides new strategies for the design of lead compounds for related cardiovascular diseases treatment.     

甜叶菊提取液对星斑川鲽生长性能和生理生化指标的影响

试验采用添加甜叶菊提取液的饲料饲喂星斑川鲽56d后,进行形体、生长和生理生化指标的测．定,结果表明,添加甜叶菊提取液显著提高了饲料系数、高密度脂蛋白含量及超氧化物歧化酶活性,对其他指标无显著影响。     

红松仁蛋白对实验小鼠血脂代谢的影响

利用高脂饲料建立实验小鼠模型,然后灌胃不同剂量的红松仁蛋白,4周后检测血清中总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)及高密度脂蛋白胆固醇(HDL-C)的含量.结果表明,红松仁蛋白能明显降低肥胖小鼠血清中TC、TG、LDL-C的含量,升高HDL-C的含量,红松仁蛋白对肥胖小鼠具有降血脂的作用.     

有机Cr对产蛋鸡生产性能及蛋黄胆固醇质量分数的影响

前后做了２个试验．试验Ⅰ选用８０只６０周龄海兰褐商品蛋鸡,随机分为１个对照组（ＣＫ）和４个处理组（Ｔ１、Ｔ２、Ｔ３、Ｔ４）．处理组Ｔ１、Ｔ２分别在日粮中添加质量分数为０．４×１０－ ６和０．８×１０－ ６（以Ｃｒ计）的无机氯化铬（ＣｒＣ１３·６Ｈ２Ｏ）;处理组Ｔ３、Ｔ４分别在日粮中添加质量分数为０．４×１０－ ６和０．８×１０－ ６（以Ｃｒ计）的铬酵母（Ｃｒｙｅａｓｔ, Ｃｒ－Ｙ）．试验Ⅱ选用９０只５５周龄父母代种用蛋鸡,同样分成１个ＣＫ 组和４个处理组（ｔ１、ｔ２、ｔ３、ｔ４）．处理组ｔ１,ｔ２分别在日粮中添加质量分数为０．４×１０－ ６和０．８×１０－ ６（以Ｃｒ计）的Ｃｒ－Ｙ;ｔ３,ｔ４分别在日粮中添加质量分数为０．４×１０－ ６和０．８×１０－ ６（以Ｃｒ计）的烟酸铬（Ｃｒ ｎｉｃｏｔｉｎａｔｅ, Ｃｒ－Ｎｉｃ）．２个试验均为期１个月．结果表明,日粮补充无机Ｃｒ或有机Ｃｒ对产蛋鸡各项生产性能未见明显影响,但于试验未,添加有机Ｃｒ组的蛋黄胆固醇质量分数和血清总胆固醇水平均比ＣＫ组和无机Ｃｒ组显著降低,而血清高密度脂蛋白胆固醇水平则有所提高;有机Ｃｒ组中质量分数为０．８×１０－ ６的与０．４×１０－ ６的相比,前者作?     

The influences of dietary linseed oil and saturated fatty acids on caecal enterocytes in Arctic char (Salvelinus alpinus L.): a quantitative ultrastructural study

Arctic char (Salvelinus alpinus L.) were fed over a three-week period with a commercial diet or one of seven casein-based diets. The latter were either lipid-free or supplemented with 50–200 g linseed oil kg^–1 diet by dry weight, 160 g linseed oil and 40 g 14:0 or 160 g linseed oil and 40 g 16:0. Three fish having filled guts were sampled from each dietary group and analysed for ultrastructural changes in the pyloric caecum.Increasing the dietary lipid level increased the accumulation of lipid droplets in columnar absorptive enterocytes from about 9% of epithelial volume in fish fed a diet of 50 g linseed oil, to almost 61% in fish fed a diet of 200 g linseed oil. Replacing linseed oil in the diet with 14:0 (160 g linseed oil + 40 g 14:0 kg^–1 diet) appeared to produce a smaller lipid loading (roughly 53%) but the difference was not statistically significant. However, replacing 40 g linseed oil with 40 g of 16:0 in the diet decreased lipid loading significantly to just under 10%. Epithelial damage to enterocytes was assessed using a ranking scale based on ultrastructural signs of cell and organelle swelling and degeneration. The extent of damage closely followed the level of lipid loading, being lowest in fish fed the lipid-free or low-lipid (damage index 0.07–0.13) diets, and highest in char maintained on a diet containing 200 g linseed oil (index 1.41). Replacing linseed oil with 14:0 (160 g linseed oil + 40 g 14:0) appeared to reduce the damage index to 0.77 but this was not significant. However, a significant reduction of the damage index to 0.27 was observed when linseed oil was replaced by 16:0.We conclude that higher dietary linseed oil promotes lipid droplet accumulation in enterocytes. The droplets are probably related to the amount of polyunsaturated fatty acids in the lipid. Intracellular droplet formation and cellular damage are both reduced by adding saturated fatty acids to the diet. This could be related to disruptions in the lipoprotein assembly rate. The cellular damages observed with high lipid diets are likely to be pathological and may lead to intestinal malfunction and represent a major infection route for pathogenic bacteria.     

苜蓿总黄酮对小鼠脂类代谢及氧自由基的影响

试验结果显示：灌胃给予苜蓿总黄酮（TFA）的小鼠全血中甘油三酯（TG）和低密度脂蛋白胆固醇（LDL—C）的含量明显降低（P〈0．05）,而高密度脂蛋白胆固醇（HDL—C）含量升高,而且其肝脏和肾脏组织匀浆中过氧化物歧化酶（SOD）的活性显著升高（P〈0．05）,丙二醛（MDA）的含量降低。因此得出结论：TFA具有降血脂、降低低密度脂蛋白胆固醇含量、预防和减轻动脉硬化的作用;同时也具有抑制氧自由基损伤、防止脂质过氧化的作用。     

A Carotenoid Algal Preparation Containing Phytoene and Phytofluene Inhibited LDL Oxidation In Vitro

The antioxidative effect of the carotenoids phytoene and phytofluene in biological systems has not yet been studied. We therefore sought to investigate the effect of these carotenoids, isolated from the alga Dunaliella bardawil, in a biological system and used the in vitro low density lipoprotein (LDL) oxidation method to assay their antioxidative effects. We found that similar to beta-carotene and alpha-tocopherol, a carotenoid algal preparation containing phytoene and phytofluene inhibited LDL oxidation. These findings and the presence of phytoene and phytofluene in human tissues suggest that they can be part of the defense system against oxidative stress.