基于转录组学研究岩藻黄素在扰动剪切应力对EPCs炎性及增殖影响

目的 在扰动剪切应力（Oscillatory shear stress, OSS, ±4 dynes/cm2, 1 Hz）作用下内皮祖细胞（Endothelial progenitor cells, EPCs）转录组学数据生物信息学分析的基础上,探讨岩藻黄素（Fucoxanthin, FUCO）对OSS作用下的EPCs炎性、增殖以及细胞周期等生物活性改变的影响作用。方法 采用Flexcell flow STR-4000流体系统模拟体内扰动流剪切应力环境;利用Illumina高通量测序平台对相应处理的EPCs进行转录组测序分析,并对筛选到的差异蛋白编码基因进行功能以及通路分析;利用实时荧光定量PCR技术（RT-qPCR）验证相应生物信息学数据;Western blot（WB）检测筛选基因-前列腺素内过氧化物合酶2（PTGS2）蛋白表达;采用EdU和PI染色分别进行EPCs增殖和周期检测。结果 与静止对照组相比,共计差异表达基因1066个,涉及细胞增殖和死亡、感染性疾病等信号转导通路;GO功能分析显示,该类基因功能主要影响的过程有细胞及细胞组分、细胞进程、细胞器及生物进程等生物活动;根据P值<0.05且Fold change（FC）>2的条件,筛选显著差异基因数17个,并经RT-qPCR以及WB验证,显示PTGS2 mRNA差异表达最为显著（P<0.001）,PTGS2蛋白表达差异明显（P<0.05）;进一步的结果显示,与OSS组EPCs相比,FUCO处理的OSS组EPCs中PTGS2 mRNA表达显著降低（P<0.001）,其蛋白表达被抑制（P<0.05）,并且FUCO处理过的OSS组EPCs增殖活性以及DNA合成能力增强。结论 结合转录组数据基础,提示FUCO能够显著降低OSS引发的EPCs炎症反应,尤其明显抑制炎性因子PTGS2表达;促进EPCs细胞增殖和 DNA合成,这为FUCO临床干预EPCs进而完善心血管疾病干细胞治疗提供理论依据。     

Fucoxanthin Protects Cultured Human Keratinocytes against Oxidative Stress by Blocking Free Radicals and Inhibiting Apoptosis

Fucoxanthin is an important carotenoid derived from edible brown seaweeds and is used in indigenous herbal medicines. The aim of the present study was to examine the cytoprotective effects of fucoxanthin against hydrogen peroxide-induced cell damage. Fucoxanthin decreased the level of intracellular reactive oxygen species, as assessed by fluorescence spectrometry performed after staining cultured human HaCaT keratinocytes with 2'',7''-dichlorodihydrofl uorescein diacetate. In addition, electron spin resonance spectrometry showed that fucoxanthin scavenged hydroxyl radical generated by the Fenton reaction in a cell-free system. Fucoxanthin also inhibited comet tail formation and phospho-histone H2A.X expression, suggesting that it prevents hydrogen peroxideinduced cellular DNA damage. Furthermore, the compound reduced the number of apoptotic bodies stained with Hoechst 33342, indicating that it protected keratinocytes against hydrogen peroxide-induced apoptotic cell death. Finally, fucoxanthin prevented the loss of mitochondrial membrane potential. These protective actions were accompanied by the down-regulation of apoptosispromoting mediators (i.e., B-cell lymphoma-2-associated x protein, caspase-9, and caspase-3) and the up-regulation of an apoptosis inhibitor (B-cell lymphoma-2). Taken together, the results of this study suggest that fucoxanthin defends keratinocytes against oxidative damage by scavenging ROS and inhibiting apoptosis.     

褐藻素对HSC-T6细胞生长和凋亡的影响

目的:探讨褐藻素对HSC-T6细胞生长和凋亡的影响。方法:将HSC-T6细胞分为空白对照组、阴性对照组及药物组,用不同浓度的褐藻素培养HSC-T6细胞。采用CCK-8检测在24 h、48 h和72 h褐藻素对HSC-T6细胞活力变化的影响,流式细胞术检测细胞周期和凋亡,Western blot法分别检测Bcl-2和Bax的蛋白表达。结果:与空白对照组相比,CCK-8检测的结果表明,褐藻素在一定浓度范围内(15~75μmol/L)内能显著抑制HSC-T6细胞的活力(P0.01),呈剂量和时间依赖性。流式细胞术结果显示,24 h后高浓度(60μmol/L)组对HSC-T6细胞周期影响的效果显著(P0.01),G_1期比例显著下降(P0.01),G_2期和S期的比例显著升高(P0.01),48 h后低浓度(15μmol/L)和中浓度(30μmol/L)组对HSC-T6细胞周期的阻滞作用增强,呈剂量依赖性(P0.05);低、中、高浓度组早期凋亡率和总凋亡率都显著升高,呈剂量依赖性(P0.05)。蛋白印迹法实验结果表明,低、中、高浓度组Bax的蛋白表达显著上调,中、高浓度组Bcl-2的蛋白表达显著下调(P0.05)。结论:褐藻素可以通过使细胞周期阻滞于S期和G2期而抑制HSC-T6细胞生长;同时能通过下调Bcl-2和上调Bax的表达而诱导HSC-T6细胞凋亡。     

岩藻黄质水凝胶透皮贴剂体外释放度及透皮率的测定

目的研究不同吸收促进剂对岩藻黄质水凝胶透皮贴剂体外释放度及透皮率的影响。方法采用HPLC法测定岩藻黄,Ultimate色谱柱(250mm×4.6mm,5μm),流动相为乙腈-水(70%~100%、100%~100%、100%~70%),检测波长为449nm,流速为1.0mL/min,进样量20μL。采用Franz透皮扩散池,以离体小鼠腹部皮肤为透皮屏障,3%薄荷醇、3%氮酮、1%,3%,5%油酸为吸收促进剂,测定岩藻黄质透皮贴剂透皮率,考察各类促渗剂对岩藻黄质经皮吸收的影响。采用《中国药典》释放度测定法第三法测定岩藻黄质水凝胶透皮贴剂体外释放度,释放介质为60%乙醇–生理盐水。结果各类吸收促进剂对岩藻黄质水凝胶透皮贴剂的经皮渗透均有一定的促进作用,以5%油酸最为显著。岩藻黄质水凝胶透皮贴剂的体外释放行为比较符合零级方程,J=11.785μg·cm-2·h-1。结论以亲水性高分子材料为基质,5%油酸为吸收促进剂,制成岩藻黄质水凝胶贴剂,为其药代动力学和临床研究研究提供依据。     

Fucoxanthin alters the apelin-13/APJ pathway in certain organs of γ-irradiated mice

Apelin-13 and APJ are implicated in different key physiological processes. This work aims at exploring the radioprotective effect of fucoxanthin (FX) on γ-radiation (RAD)-induced changes in the apelin-13/APJ pathway, which causes damage in the liver, kidney, lung and spleen of mice. Mice were administered FX (10 mg kg^–1 day^–1, i.p) and exposed to γ-radiation (2.5 Gy week^–1) for four consecutive weeks. The treatment of irradiated mice by FX resulted in a significant amendment in protein expression of the apelin-13/APJ/NF-κB signalling pathway concurrently with reduced hypoxia (hypoxia-inducible factor-1α), suppressed oxidative stress marker (malondialdehyde), enhanced antioxidant defence mechanisms (reduced glutathione and glutathione peroxidase), a modulated inflammatory response [interleukin-6 (IL-6), monocyte chemoattractant protein-1, IL-10 and α-7-nicotinic acetylcholine receptor) and ameliorated angiogenic regulators [matrix metalloproteinase (MMP-2), MMP-9 and tissue inhibitor of metalloproteinase-1), as well as the tissue damage indicator (lactate dehydrogenase) in organ tissues. In addition, there were significant improvement in serum inflammatory markers tumour necrosis factor-α, IL-10, IL-1β and C-reactive protein compared with irradiated mice. The histopathological investigation of the FX + RAD organ tissues support the biochemical findings where the improvements in the tissues’ architecture were obvious when compared with those of RAD. FX was thus shown to have a noticeable radioprotective action mediated through its regulatory effect on the apelin-13/APJ/NF-κB signalling pathway attributed to its antioxidant and anti-inflammatory activity that was reflected in different physiological processes. It could be recommended to use FX in cases of radiation exposure to protect normal tissues.     

高效液相色谱法测定海胆黄中岩藻黄质与岩藻黄醇

目的 建立高效液相色谱法同时测定海胆黄中岩藻黄质及岩藻黄醇的方法。方法 采用高效液相色谱法,色谱柱为Hypersil ODS C18(4.6 mm×250 mm,５μｍ),流动相为甲醇-水(90:10) ,检测波长为449 nm,流速１mL.min^－１,进样量10 μＬ。结果 岩藻黄质与岩藻黄醇在此色谱条件下获得良好分离, 岩藻黄质在0.88～56 μg/mL范围内呈良好线性 (y = 102.75x + 4.4072,r = 0.9999, 平均加样回收率为97.76%, RSD 1.88%),岩藻黄醇在0.88～56 μg/mL范围内呈良好线性 (y = 92.906x + 2.2318,r = 0.9999,平均加样回收率为95.28%, RSD 1.85%)。结论 本方法准确、可靠, 可用于海胆等生物样品中岩藻黄质及岩藻黄醇的含量测定。     

Kinetics and molecular docking studies of fucosterol and fucoxanthin,BACE1 inhibitors from brown algae Undaria pinnatifida and Ecklonia stolonifera

Since the action of β-site amyloid precursor protein cleaving enzyme 1 (BACE1) is strongly correlated with the onset of Alzheimer's disease (AD), the development of BACE1 inhibitors as therapeutic agents is being vigorously pursued. In our ongoing research aimed at identifying anti-AD remedies derived from maritime plants, we evaluated the BACE1 inhibitory activities of fucosterol and fucoxanthin from Ecklonia stolonifera and Undaria pinnatifida. In vitro anti-AD activities were performed via BACE1 inhibition assays, as well as enzyme kinetic and molecular docking predictions. Based on enzyme-based assays, fucosterol and fucoxanthin showed noncompetitive and mixed-type inhibition, respectively, against BACE1. In addition, docking simulation results demonstrated that the Lys224 residue of BACE1 interacted with one hydroxyl group of fucosterol, while two additional BACE1 residues (Gly11 and Ala127) interacted with two hydroxyl groups of fucoxanthin. Moreover, the binding energy of fucosterol and fucoxanthin was negative (−10.1 and −7.0 kcal/mol), indicating that hydrogen bonding may stabilize the open form of the enzyme and potentiate tight binding of the active site of BACE1, resulting in more effective BACE1 inhibition. The results suggest that fucosterol and fucoxanthin may be used beneficially in the treatment of AD and provide potential guidelines for the design of new BACE1 inhibitors.     

Beneficial effects of Undaria pinnatifida ethanol extract on diet-induced-insulin resistance in C57BL/6J mice

This study was performed to evaluate the beneficial effect of Undaria pinnatifida ethanol extract (UEFx) on insulin resistance in diet-induced obese mice. A high-fat diet was supplemented with the UEFx at 0.69% (wt/wt) dose, which contains an equivalent amount of 0.02% fucoxanthin (wt/wt), or with Fx at 0.02% (wt/wt) dose in diet. After 9 weeks, both UEFx supplement significantly lowered the amount of visceral fat, the size of adipocyte, the fasting blood glucose concentration, the plasma insulin and the insulin resistance index similar to pure as shown by Fx supplement, compared to the high-fat (HF) control group. Blood glucose level was negatively correlated with hepatic glucokinase activity (r = −0.533, p < 0.05), whereas positively correlated with hepatic gluconeogenic enzyme activities (r = 0.463, p < 0.05 for glucose-6-phosphatase; r = 0.457, p < 0.05 for phosphoenolpyruvate carboxykinase). Ratio of hepatic glucokinase/glucose-6-phosphatase and glycogen content were significantly elevated by the UEFx and Fx supplements. Supplementation of the UEFx as well as Fx seemed to stimulate the β-oxidation activity and inhibit the phosphatidate phosphohydrolase activity resulting in a decrease in the hepatic lipid droplet accumulation. The results indicate that the UEFx can prevent insulin resistance and hepatic fat accumulation that is partly mediated by modulating the hepatic glucose and lipid homeostasis in the high fat-induced obese mice.