Vaspin对巨噬细胞THP-1向泡沫细胞转变的抑制作用

目的 腹腔脂肪型丝氨酸蛋白酶抑制剂(visceral adipose tissue-derived serine protease inhibitor, vaspin)是新发现的脂肪因子,对代谢性疾病具有改善作用。该研究旨在研究vaspin对体外培养的THP-1细胞泡沫化的影响。方法 100nM佛波酯孵育THP-1巨噬细胞48h后分为对照组,氧化低密度脂蛋白组(ox-LDL浓度50μg/ml,48h),vaspin干预组(vaspin终浓度100ng/ml,预孵24h);采用油红0染色法检测vaspin对THP-1细胞泡沫化的影响;Real-time PCR和Western blot法检测vaspin对THP-1细胞中酰基辅酶A胆固醇酰基转移酶-1(acy1-coenzyme A:cholesterol acyltrasferase-1,ACAT-1)、ATP结合盒转运体A1(ATP binding casstte transporterA1,ABCA1)及细胞清道夫受体-A1(scavenger receptor-A1, SR-A1)mRNA及蛋白表达水平的影响。结果 与ox-LDL组比较,ox-LDL+vaspin组巨噬细胞泡沫化程度明显下降(P＜0.05);ox-LDL+vaspin组ACAT-1和SR-A1 mRNA及蛋白表达水平明显降低(P＜0.05),而ABCA1 mRNA及蛋白表达水平明显升高(P＜0.05)。结论 vaspin能够抑制巨噬细胞向泡沫细胞的转化,发挥抗动脉粥样硬化(atherosclerosis, As)的作用。     

去甲肾上腺素对THP-1源性巨噬细胞SR-A1和转化生长因子-β1表达的影响

目的:探讨去甲肾上腺素对人THP-1源性巨噬细胞SR-A1和转化生长因子(TGF)-β1表达的影响.方法:不同浓度的去甲肾上腺素(10 pmol/L～10 μmol/L)作用THP-1源性巨噬细胞24 h,运用逆转录多聚酶链反应检测SR-A1和TGF-β1 mRNA的表达,Western-Blot检测SR-A1蛋白的表达,酶联免疫吸附试验检测TGF-β1蛋白的表达.结果:1 μmol/L及10 μmol/L的去甲肾上腺素作用THP-1源性巨噬细胞后,SR-A1 mRNA和蛋白表达上调,100 nmol/L 、1 μmol/L及10 μmol/L的去甲肾上腺素引起巨噬细胞中 TGF-β1 mRNA和蛋白水平均下降(均P＜0.05).结论:应激浓度的去甲肾上腺素能增加THP-1源性巨噬细胞SR-A1的表达,降低TGF-β1的表达.     

β3-AR mRNA表达与SR-AⅠ/Ⅱ基因敲除小鼠对膳食诱导肥胖易感的关系

目的观察SR-AⅠ/Ⅱ基因敲除小鼠白色脂肪组织中β3-AR mRNA的表达,探讨其与SR-AⅠ/Ⅱ基因敲除小鼠肥胖易感的关系。方法应用荧光定量RT-PCR检测小鼠附睾周白色脂肪组织中β3-AR mRNA的表达;图像分析法评估附睾周脂肪细胞形态学变化;酶法检测TG、TC、LDL-C等血脂水平。结果:SR-AⅠ/Ⅱ基因敲除小鼠白色脂肪组织β3-AR mRNA表达量低于野生对照小鼠;血清TG、TC、LDL-C水平高于野生系对照小鼠;附睾周脂肪细胞面积和直径均大于对照小鼠。结论:SR-AⅠ/Ⅱ基因敲除小鼠对膳食诱导的肥胖易感可能与其白色脂肪组织β3-AR mRNA表达降低有关。     

金属硫蛋白对ApoE基因缺陷小鼠血脂、动脉粥样硬化及主动脉SR-AⅠ表达的影响

目的观察金属硫蛋白对ApoE基因缺陷小鼠血脂、动脉粥样硬化以及主动脉AⅠ型清道夫受体(SR-AⅠ)表达的影响。方法将20只6周龄雄性ApoE基因缺陷小鼠随机分为高脂模型组、金属硫蛋白组各10只,高脂饮食喂养13周;取10只野生雄性小鼠作为正常对照组,正常饮食喂养13周。13周后摘眼球取血测定血清总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)。处死小鼠后取主动脉,HE染色及SR-AⅠ免疫组织化学染色后观察主动脉血管壁形态学变化;用Western Blot和RT-PCR法检测主动脉壁组织中的SR-AⅠ蛋白和mR-NA表达。结果金属硫蛋白组TC、TG、LDL-C与高脂高脂模型组比较P均>0.05;金属硫蛋白组小鼠肝肾功能和肌酸磷酸激酶指标与高脂模型组相比P均>0.05。与正常对照组相比,高脂模型组主动脉粥样硬化病变程度明显加重,主动脉壁SR-AⅠ蛋白和mRNA表达均明显增加(P均<0.05);与高脂模型组相比,金属硫蛋白组主动脉粥样硬化程度减轻,SR-AⅠ蛋白和mRNA的表达均降低(P均<0.05)。结论金属硫蛋白对ApoE基因缺陷小鼠血脂无明显影响,但可降低其主动脉壁SR-AⅠ蛋白和mRNA,降低粥样硬化病变程度。     

Class A scavenger receptor activation inhibits endoplasmic reticulum stress-induced autophagy in macrophage

Macrophage death in advanced atherosclerosis promotes plaque necrosis and destabilization.Involvement of autophagy in bulk degradation of cellular components has been recognized recently as an important mechanism for cell survival under endoplasmic reticulum（ER） stress.We previously found that the engagement of class A scavenger receptor（SR-A） triggered JNK-dependent apoptosis in ER-stressed macrophages.However,pro-apoptotic mechanisms mediated by SR-A are not fully understood.Therefore,we sought to see if SR-A mediated apoptosis was associated with autophagy in macrophages.Here,we showed that fucoidan inhibited microtubule-associated protein light chain 3-phospholipid conjugates（LC3-Ⅱ） formation as well as the number of autophagosomes under ER stress.The inhibition of LC3-Ⅱ formation was paralleled by the activation of the mTOR pathway,and the inhibition of mTOR allowed LC3-Ⅱ induction in macrophages treated with thapsigargin plus fucoidan.Furthermore,apoptosis induced by fucoidan was prevented under ER stress by the mTOR inhibitor.We propose that fucoidan,a SR-A agonist,may contribute to macrophage apoptosis during ER stress by inhibiting autophagy.     

高脂饮食诱导ApoE/CD36/SR-A三敲除小鼠肾脏损害及其机制

目的 探讨低密度脂蛋白受体相关蛋白(low density lipoprotein receptor-related protein ,LRP1)、清道夫受体CD36、SR-A在脂质诱导肾脏损伤中的作用.方法 雄性ApoE/CD36/SR-A三敲除小鼠12只,按随机数字表法分为普通组和高脂组.检测血清淀粉样蛋白(serum amyloid A protein,SAA),IL-6、脂质水平及尿蛋白.油红"O"染色及酶法检测肾组织内脂质沉积情况.HE、过碘酸-希夫(periodic acid Schiff reaction,PAS)、马松(Masson)方法 观察肾脏形态学改变,定量PCR技术,Western blot与免疫组化技术检测肾组织相关因子水平.结果 高脂组脂质水平[TC(51.96±5.60)、LDL(16 79±4.80)mmol/L]显著高于普通组[TC(18.11±3.07)、LDL(3.27±1.79) mmol/L](P<0.05).肾脏脂质的沉积明显升高,高脂组尿蛋白[(2.90±0.50)mg/ml]显著高于普通组[(1.85±0.18)mg/ml] (P<0.05),肾脏病理改变显著,进一步检测发现高脂组上调了LRP1(增高2.23倍)、肾脏Ⅰ型胶原蛋白、转化生长因子(TGF-β)、纤维连接蛋白(Fibronectin)mRNA与蛋白的表达.结论 LRP1可能参与肾脏泡沫细胞的形成及肾脏的损伤,SR-A,CD36不能解释泡沫细胞形成的全部机制.     

A novel scavenger receptor-cysteine-rich (SRCR) domain containing scavenger receptor identified from mollusk mediated PAMP recognition and binding

Scavenger receptors (SRs) are significant endocytic receptors contributing to constant internal environment. SR-cysteine-rich (SRCR) domain-containing SR is the most important class of SRs which has been so far reported exclusively in mammals and birds. In the present study, a novel SRCR domain-containing SR (CfSR) was firstly identified from scallop Chlamys farreri. The full-length cDNA of CfSR was of 2639 bp encoding a polypeptide of 804 amino acids with a signal peptide, six SRCR domains, a UPAR-like domain and a ShK toxin-like domain. All the SRCR domains contain highly conserved six cysteine residues to form three pairs of intradomain disulfide, among which SRCR-D5 was assumed to participate in ligand-binding. An attachment site of sequence CTTPLCN was found in UPAR-like domain, indicating CfSR was an anchor protein. This prediction was confirmed by its localization on the outer surface of hemocytes with immunofluorescence assay. The mRNA expression of CfSR was up-regulated significantly by the stimulations of lipopolysaccharides, peptidoglycan and β-glucan. A truncated CfSR (from V⁴⁵⁶ to T⁸⁰⁴) including SRCR-D5 was recombined and expressed in Escherichia coli, and the recombined protein displayed unique broad ligand-binding properties not only for acetylated low density lipoprotein (Ac-LDL) and dextran sulfate, but also for various pathogen associated molecular patterns, such as LPS, PGN, mannan and zymosan. All the results indicated that CfSR, the most primitive SR identified to date, was a versatile PRR involved in immune recognition, and the existence of functional SR might trace back to at least mollusk phylum.     

Effects of rosiglitazone and atorvastatin on the expression of genes that control cholesterol homeostasis in differentiating monocytes

We studied the effects of 5 microM atorvastatin, 2 microM rosiglitazone and their combination on intracellular cholesterol levels and on the expression of genes controlling cholesterol trafficking in human monocytes during their differentiation into macrophages. Our results show that treatment with rosiglitazone caused an increase in CD36 mRNA and protein levels (2.7- and 2.9-fold, P<0.001), but significantly induced the expression of most genes related to cholesterol efflux: ABCA1 mRNA (23%, P<0.05) and protein (2.4-fold, P<0.05), apo E protein (2.4-fold, P<0.05), caveolin-1 mRNA (2.6-fold, P<0.001) and SR-BI mRNA (1.9-fold, P<0.001) and protein (3-fold, P<0.01). As a consequence, rosiglitazone treatment reduced intracellular free cholesterol levels by 22% (P<0.01). Treatment with 5 microM atorvastatin caused the opposite effect on the expression of cholesterol efflux-related genes, which was generally reduced: ABCA1 mRNA (71%, P<0.05), apo E mRNA (46%, P<0.001) and protein (5.6-fold, P<0.001), and CYP27 mRNA (15%, P<0.05). Despite these reductions, intracellular total and free cholesterol levels were also reduced by 30% (P<0.01), an effect that can be attributed to the inhibition of de novo cholesterol synthesis by the statins. The combination of rosiglitazone with atorvastatin attenuated CD36 induction, and caused reductions similar to those caused by the statin alone on the expression of genes involved in cholesterol efflux and on intracellular cholesterol levels.     

与动脉粥样硬化密切相关的清道夫受体

动脉粥样硬化(atherosclerosis,AS)是一种严重危害人类健康的心血管疾病,其发病机制与血脂代谢紊乱密切相关。流行病学的大量研究证明,血浆低密度脂蛋白胆固醇(1ow density lipoprotein choles-terol,LDL-C)浓度与AS的发生呈正相关,高密度脂蛋白胆固醇(high density lipoprotei