Degradation of FAK-targeting by proteolytic targeting chimera technology to inhibit the metastasis of hepatocellular carcinoma

Liver cancer is a prevalent malignant cancer,ranking third in terms of mortality rate.Metastasis and recurrence primarily contribute to the high mortality rate of liver cancer.Hepatocellular carcinoma(HCC)has low expression of focal adhesion kinase(FAK),which increases the risk of metastasis and recurrence.Nevertheless,the efficacy of FAK phosphorylation inhibitors is currently limited.Thus,investigating the mechanisms by which FAK affects HCC metastasis to develop targeted therapies for FAK may present a novel strategy to inhibit HCC metastasis.This study examined the correlation between FAK expression and the prognosis of HCC.Additionally,we explored the impact of FAK degradation on HCC metastasis through wound healing experiments,transwell invasion experiments,and a xenograft tumor model.The expression of proteins related to epithelial-mesenchymal transition(EMT)was measured to elucidate the underlying mechanisms.The results showed that FAK PROTAC can degrade FAK,inhibit the migration and invasion of HCC cells in vitro,and notably decrease the lung metastasis of HCC in vivo.Increased expression of E-cadherin and decreased expression of vimentin indicated that EMT was inhibited.Consequently,degradation of FAK through FAK PROTAC effectively suppressed liver cancer metastasis,holding significant clinical implications for treating liver cancer and developing innovative anti-neoplastic drugs.

Comparative studies of versatile extracellular proteolytic activities of lactic acid bacteria and their potential for extracellular amino acid productions as feed supplements

Background:Increasing understanding on the functions of amino acids (AA) has led to new commercial applications and expansion of the worldwide markets.However,the current technologies rely heavily on non-food grade microorganism and chemical synthesis for the production of AA.Several studies reported that lactic acid bacteria (LAB) have the capability of producing AA owing to their well-established proteolytic system and amino acid biosynthesis genes.Hence,the objectives of this study were to explore the extracellular proteolytic activity of LAB isolated from various Malaysian fermented foods and their potential to produce AA extracellularly as feed supplements.Results:All the studied LAB isolates were versatile extracellular protease producers,whereby extracellular protease activities were detected from acidic to alkaline pH (pH 5,pH 6.5,pH 8) using qualitative and quantitative proteolytic assays.The highest proteolytic activity at pH 5 (15.76 U/mg) and pH 8 (19.42 U/mg) was achieved by Lactobacillus plantarum RG14,while Lactobacillus plantarum RS5 exhibited the highest proteolytic activity of 17.22 U/mg at pH 6.5.As for the results of AA production conducted in de Man,Rogosa and Sharpe medium and analysed by high pressure liquid chromatography system,all LAB isolates were capable of producing an array of AA.Generally,Pediococcus sp.showed greater ability for AA production as compared to Lactobacillus sp.Moreover,the studied LAB were able to produce a few major feed supplement AA such as methionine,lysine,threonine and tryptophan.P.pentosaceus TL-3 recorded the highest methionine and threonine productivity of 3.72 mg/L/h and 5.58 mg/L/h respectively.However,L.plantarum I-UL4 demonstrated a lysine productivity of 1.24 mg/L/h,while P.acidilactici TP-6 achieved up to 1.73 mg/L/h of tryptophan productivity.Conclusion:All the 17 studied LAB isolates possessed versatile extracellular proteolytic system and have vast capability of producing various amino acids including a few major feed supplement AA such as methionine,lysine,threonine and tryptophan.Despite AA production was strain dependent,the studied LAB isolates possessed vast potential and can be exploited further as a bio-agent or an alternative amino acids and bioactive peptide producers.

Effects of light intensities and photoperiods on growth and proteolytic activity in purple non-sulfur marine bacterium, <i>Afifella marina</i>strain ME (KC205142)

Afifella marina strain ME (KC205142), a purple non-sulfur bacterium was isolated from mangrove habitats of Sabah. The effects of light intensities and photoperiods on proteolytic activity in Afifella marina strain ME (KC205142) were investigated. Secretion of proteolytic enzymes in Afifella marina was preliminarily assessed by skim milk agarose media. Subsequently, light intensities, such as, dark, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500 and 5000 lux were used to evaluate the effects on proteolytic activity in Afifella marina strain ME under anaerobic condition. After that, the effect of photoperiods on proteolytic activity was monitored under anaerobic light condition (3000 lux) at 0 h (0L/24D), 6 h (6L/18D), 12 h (12L/12D), 18 h (18L/6D) and 24 h (24L/0D) of photoperiod. The highest proteolytic activity of 74.67 U was recorded at 3000 lux illumination light intensity. The proteolytic activity in bacterium Afifella marina strain ME was positively associated with the dry cell weight. The proteolytic activity of 72.67 U in bacterium Afifella marina strain ME at 18 h (18L/6D) photoperiod is not significantly different (p > 0.05) from proteolytic activity of 74.67 U recorded at continuous light (24L/0D) condition. Light intensity of 3000 lux, culture period of 48 h and a photoperiod of 18 h (18L/ 6D) were the optimum parameters for proteolytic activity in bacterium Afifella marina strain ME.

Effect of proteolytic starter culture isolated from Chinese Dong fermented pork(Nanx Wudl)on microbiological,biochemical and organoleptic attributes in dry fermented sausages

The effect of a proteolytic starter culture isolated from Nanx Wudl,on microbiological,biochemical and organoleptic attributes of dry fermented sausages was investigated during processing.Based on preliminary screening,the combination of Staphylococcus xylosus SX16 and Lactobacillus plantarum CMRC6,showing excellent proteolytic activity in vitro,was selected as the multi-strain starter(starter LS).For comparison,the single-strain starter culture of L.plantarum CMRC6(starter LB)and non-inoculated control were also tested.During fermentation,lactic acid bacteria and staphylococci dominated the microbiota and suppressed the Enterobacteriaceae growth in LS-inoculated sausages.The addition of LS starter accelerated acidification and proteolysis during ripening,improving the contents of total free amino acids and several essential free amino acids(Phe,Ile and Leu).Volatile compounds analysis revealed that LS-fermented sausage showed the highest abundance of 3-methyl-1-butanol,probably due to the inoculated S.xylosus.The inoculation of LS starter improved the sensory properties of sausages,especially the flavor attribute.Therefore,S.xylosus SX16 and L.plantarum CMRC6 are promising candidates for inclusion as multi-strain starters in the manufacture of gourmet fermented dry sausage.

Trimethylamine Adsorption Mechanism on Activated Carbon and Removal in Water and Oyster Proteolytic Solution

In this study,seven coal-based activated carbons(ACs)were adopted to remove trimethylamine(TMA)in an aqueous solution as environmentally friendly and harmless adsorbents.The results showed that columnar AC(CAC)had a clear scale and honeycomb structures with few fragments and micropores,contributing to superior TMA removal capacity compared to granular AC(GAC)(71.67%for 6.0 mm CAC and 69.92%for 40–60 mesh GAC).In addition,the process of adsorption was accompanied by desorption,and the recommended absorbed time was 120–180 min.The short time to achieve equilibrium indicated that adsorption was kinetically controlled,and pseudo-second-order kinetics was more appropriate than pseudo-first-order kinetics in explaining the adsorption mechanism in both water and oyster enzymatic hydrolysate.The intraparticle diffusion model presented that the adsorption processes could be divided into three steps for GAC and two steps for CAC.The adsorption processes were consistent with the Freundlich model,indicating the existence of physisorption and chemisorption as multilayer adsorption.The results indicated that AC,especially CAC,has great potential for TMA elimination in aquatic product processing.

Effect of MUC2 Antisense Oligodeoxynucleotide on Cell Proliferation,Adhesion,and Proteolytic Enzyme in Human Gastric Carcinoma in vitro

Objective：To investigate the effect of MUC2 antisense oligodeoxynucleotide （ASODN） on cell proliferation, adhesion and proteolytic enzyme inhuman gastric carcinoma cell line （SGC7901）. Methods： Phosphorothioate MUC2 ASODN was synthesized and packaged by lipofectin, and then transfected to SGC7901 cells. The expression of MUC2 mRNA and protein after transfection was detected by reverse transcription-polymerase chain reaction （RT-PCR） and immunohistochemical method respectively, and the effect of MUC2 ASODN on cell proliferation, adhesion and proteolytic enzyme was determined by flow cytometry（FCM）, MTT method, Rose Bengal and immunohistochemical method. Results： Compared with the blank control group, ASODN efficiently downregulated the expression of MUC2 mRNA and protein in SGC7901 cells 48h after transfection（P〈0.01）. Various concentrations of ASODN could significantly inhibit the growth of SGC7901, and the inhibition peaked at the 48th hour after transfection（P〈0.05）. The apoptosis rate of the experimental group was about 4.38%, and the percentage of S-phase cells rose while G0/G1-phase cells fell because most of them were blocked at S-phase. In addition, cells treated with MUC2 ASODN showed lower adhesion ability with matrix and endothelial cells than control cells in vitro（P〈0.01）. By immunohistochemical method, the upregulation of E-cadherin proteins and the downregulation of MMP2 and cathepsinD proteins were also observed（P〈0.05）. Conclusion： MUC2 ASODN could efficiently inhibit SGC7901 cell proliferation, reduce cell adhesion ability and downregulate the expression levels of proteolytic enzyme in vitro.

Phenotypic and Genetic Characterization of Bacillus Species Exhibiting Strong Proteolytic Activity Isolated from Terasi,An Indonesian Fermented Seafood Product

In this study, two bacilli strains namely S2-3 and S4-5, isolated from Terasi, a traditional fermented seafood product of Indonesia, were studied in terms of their phenotypic and genotypic properties. Both strains are of great interests due to their high proteolytic activity. Initially, they were subjected to morphological determination and a series of biochemical tests. These bacteria were Gram-positive, endospore-forming bacilli. Based on 16S rRNA gene sequence analysis, the identities of the strains S2-3 and S4-5 were confirmed as Bacillus thuringiensis and B. subtilis, respectively. Additionally, the two strains were also evaluated for their antibiogram profiles. It was found that they were susceptible to chloramphenicol, erythromycin, kanamycin, tetracycline and vancomycin and resistant to ampicillin and intermediately susceptible to bacitracin.

凝固剂对干酪风味、质构及蛋白水解代谢特征的影响

干酪蛋白质形成凝胶的过程,是干酪加工的关键环节。凝固剂的种类及用量与干酪凝胶的品质特征密切相关。该文综述酶类凝固剂及酸类凝固剂对干酪风味、质构及蛋白水解代谢特征的影响,并对干酪凝固剂加工及应用工业面临的机遇与未来发展趋势进行探讨,以期为今后干酪产品开发及品质提升提供参考。

酿酒酵母表面展示NX1101蛋白酶全细胞催化剂制备火麻多肽

酶解法火麻肽制备具有安全性好、能耗低、营养损失小等优点。研究在综合脱脂火麻仁籽粕蛋白提取以及蛋白水解酶筛选的基础上,以穿梭质粒pYD1为表达载体,将源于牛肠道宏基因组文库中的蛋白水解酶NX1101锚定在酿酒酵母菌株(EYB100)表面,并以此重组菌株作为全细胞催化剂制备火麻多肽。酶学性质分析发现:该全细胞催化剂的最适反应pH值为8.0,在pH 8~10酶活稳定性较高,为耐碱性全细胞催化剂;其最适反应温度50℃,在50℃以下时酶活稳定性较高。脱脂火麻蛋白经表面展示表达NX1101的重组酵母全细胞催化剂酶解后,共获得1095个多肽,其中氨基酸数量≤10的短肽数量达140个。全细胞催化剂酶解效率相较常规酶解技术(以碱性蛋白酶粉剂为对照)增加6.5倍以上。

医院制剂蛇药酒抑制眼镜蛇毒酶活性的实验研究

目的探讨医院制剂蛇药酒抗眼镜蛇毒中4种主要酶活性的效果。方法采用不同浓度蛇药酒与蛇毒共孵育作为蛇药酒组,同时设置无蛇药酒的蛇毒对照组。通过琼脂平板法比较蛇药酒组及蛇毒对照组产生透明圈的直径,以检测不同浓度蛇药酒对眼镜蛇毒中磷脂酶A_(2)(PLA_(2))、纤维蛋白原溶酶(以下简称纤溶酶)的抑制作用;分别以福林法和浊度法检测两组的蛋白水解酶和透明质酸酶活性,观察蛇药酒对眼镜蛇毒中蛋白水解酶、透明质酸酶的抑制作用。结果蛇药酒浓度为0.0008、0.004、0.02、0.1、0.5 mg/ml时,对眼镜蛇毒中的PLA_(2)有较强的抑制作用;蛇药酒浓度为1.3、13、130 mg/ml时,可明显抑制纤溶酶活性;蛇药酒浓度为0.5、2、8、32 mg/ml时,对蛇毒中蛋白水解酶抑制作用显著;蛇药酒浓度为0.0625、0.125、0.25、0.5、1 mg/ml时,对眼镜蛇毒中透明质酸酶抑制作用呈剂量依赖性。结论医院制剂蛇药酒在体外有直接抑制眼镜蛇毒中PLA_(2)、纤溶酶、蛋白水解酶及透明质酸酶的作用。

基于蛋白降解靶向嵌合体的IRAK4降解剂的设计、合成及生物活性评价

目的 设计并合成具有抗肿瘤活性的白细胞介素-1受体相关激酶4(IRAK4)降解剂。方法 将IRAK4蛋白配体与E3连接酶配体经不同类型和长度的连接链进行连接,合成目标化合物,其结构经MS谱和~1H NMR谱确证。以大B细胞淋巴瘤细胞OCI-LY10为测试细胞株,对所合成的目标化合物进行体外抗肿瘤活性评价以及对IRAK4的降解测试。结果 合成了9个靶向IRAK4的降解剂,活性测试结果显示目标化合物均可抑制大B细胞淋巴瘤细胞OCI-LY10细胞增殖,其中化合物Ⅲ、Ⅶ、Ⅷ、Ⅸ对IRAK4有较强的降解活性,半数最大降解浓度(DC_(50))值在1~10 nmol·L^(-1)。结论 利用蛋白降解靶向嵌合体技术,通过对IRAK4的降解,实现对肿瘤细胞的增殖抑制,值得进一步研究。

人参不同炮制品蛋白酶解肽对LPS诱导RAW264.7细胞的抗炎作用研究

研究从人参炮制品生晒参、红参、黑参中筛选出具有抗炎作用的蛋白酶解肽并进行对比分析。采用低温浸提法从三种炮制品中提取人参不同炮制品蛋白,采用分步酶解法,利用碱性蛋白酶、中性蛋白酶和胃蛋白酶对三种人参蛋白进行酶解,得到BGP(黑参蛋白酶解肽)、RGP(红参蛋白酶解肽)、SGP(生晒参蛋白酶解肽)三种酶解产物;使用超滤膜进行分离,分别得到不同分子量的超滤组分。通过建立脂多糖(LPS)诱导的RAW264.7炎症模型确定了具有最强抗炎活性的组分。酶联免疫法测定活性组分对RAW264.7细胞分泌一氧化氮(NO)、肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)的影响。分析三种蛋白酶解肽的氨基酸组成及含量。采用多元统计分析筛选出人参三种炮制品的差异性氨基酸并探究其与抑制RAW264.7细胞分泌细胞因子之间的关系。结果表明,人参三种炮制品蛋白酶解肽小于1 kDa组分较其他组分相比,对RAW264.7细胞增殖的作用最强且在质量浓度为50~200μg/mL时可显著抑制NO、TNF-α、IL-6、IL-1β的分泌(P<0.05)。质量浓度为200μg/mL时,三种蛋白酶解肽给药组对细胞因子释放的抑制作用最强,且BGP-4对细胞因子释放的抑制作用高于RGP-4和SGP-4,具有显著差异(P<0.05)。三种蛋白酶解肽均含有17种氨基酸,但含量存在明显差异。其中,苯丙氨酸含量最高且为三种人参炮制品差异氨基酸与抑制炎症因子的分泌密切相关。本研究初步探讨了炮制对人参抗炎活性的影响,并筛选出不同炮制品的差异性氨基酸,为人参炮制品的加工提供了参考依据。

针药联合对阿尔兹海默病模型大鼠小脑皮质谷氨酸受体2及Caspase-3表达的影响

目的观察针药联合对阿尔兹海默病(AD)模型大鼠小脑皮质谷氨酸受体(GluR2)及天冬氨酸蛋白水解酶(Caspase-3)表达的影响,探讨小脑在AD发病机制中的作用。方法30只雄性SD大鼠随机分为5组:对照组(C组)、模型组(M组)、电针组(EA组)、天麻素组(Gas组)、针药联合组(EA+Gas组),每组6只。C组不作任何处理;M组大鼠给予双侧海马内微量注射5μL的Aβ1-42进行造模;EA组予以频率2 Hz、强度1mA的电针刺激,选取穴位“大椎”“百会”“足三里”,每日30 min,连续4周。Gas组予以腹腔注射Gas注射液(10 mg/kg),每天1次,连续4周;EA+Gas组同时予以电针和Gas治疗,连续4周。Morris水迷宫检测大鼠学习记忆行为能力,Nissl染色和免疫组化方法观察各组大鼠小脑皮质细胞形态和数量,Western Blot法检测各组GluR2和Caspase-3蛋白的表达。结果M组小脑皮质中浦肯野层细胞数量减少(P<0.05),GluR2表达降低(P<0.05),Caspase-3表达增高(P<0.05);各治疗组较M组的细胞形态趋于正常,GluR2的表达增加(P<0.05),Caspase-3的表达降低(P<0.05),其中以EA+Gas组改变最为明显。结论电针、天麻素及针药联合均可通过调节GluR2和Caspase-3的表达水平进而改善AD模型大鼠学习记忆能力,其中针药联合效果最佳。

NLRC4、DPP3、Caspase-8在脓毒症心肌损伤诊断及预后评估中的价值

目的:探讨核苷酸结合寡聚化结构域样受体蛋白4(NLRC4)、二肽基肽酶Ⅲ(DPP3)、半胱氨酸天冬氨酸蛋白水解酶-8(Caspase-8)对脓毒症心肌损伤的诊断和预后评估价值。方法:选取本院收治的133例脓毒症患者为研究对象,根据是否合并心肌损分为心肌损伤组(44例)和非心肌损伤组(89例),根据患者预后将心肌损伤患者分为存活组(28例)和死亡组(16例),比较不同组间NLRC4、DPP3、Caspase-8水平;并分析心肌损伤组NLRC4、DPP3、Caspase-8水平与氨基末端脑钠肽前体(NT-proBNP)、心肌肌钙蛋白(cTnI)、肌酸激酶同工酶(CK-MB)水平的相关性。ROC曲线分析NLRC4、DPP3、Caspase-8对心肌损伤的诊断和预后评估价值。结果:与非心肌损伤组比较,心肌损伤组患者NLRC4、DPP3、Caspase-8水平升高,与存活组比较,死亡组NLRC4、DPP3、Caspase-8水平升高(P<0.05),且NLRC4、DPP3、Caspase-8水平与NT-proBNP、cTnI、CK-MB水平均呈正相关(P<0.05);ROC曲线分析结果显示,NLRC4、DPP3、Caspase-8单独及联合检测诊断心肌损伤的AUC均>0.8,评估患者预后的AUC均>0.7。结论:NLRC4、DPP3、Caspase-8与脓毒症心肌损伤密切相关,且三者在心肌损伤的诊断及预后评估中均具有一定临床参考价值。

面制品速冻工艺中蛋白质水解酶的应用与面团品质改进

本文通过深入研究蛋白质水解酶的分类与作用机理,以明确其在面团加工中的潜在价值。在实验中,通过采用添加蛋白质水解酶的方法,并优化了工艺参数,以观察水解酶对面团品质的影响。结果表明,蛋白质水解酶的适当应用能够显著增强面团的弹性和延展性,改善口感,并优化面制品的整体品质。综合研究结果可以看出蛋白质水解酶在面制品速冻工艺中具有显著的应用价值,为面制品的品质提升和加工优化提供了新的途径。

Casp-8通过调控NLRP3炎性小体介导的细胞焦亡减轻脓毒症引起的急性肺损伤

目的:分析半胱氨酸天冬氨酸蛋白水解酶-8(Casp-8)对脓毒症引起的急性肺损伤(ALI)的作用及其相关分子机制。方法:对40只C57BL/6小鼠使用盲肠结扎穿孔术(CLP)建立脓毒症诱导的小鼠ALI模型,将造模成功的小鼠随机分为模型组(CLP组)和CLP+Casp-8抑制剂组(CLP+Z-IETD-FMK组),每组20只。另取20只正常饲养的小鼠设为假手术组(sham组)。采用称质量法测定小鼠肺组织湿干质量比值(W/D),HE染色观察小鼠肺组织病理变化,TUNEL染色检测肺组织细胞凋亡情况,ELISA检测小鼠支气管肺泡灌洗液(BALF)中炎症因子水平,qRT-PCR检测肺组织中Casp-8 mRNA表达,Western blotting检测小鼠肺组织中Casp-8蛋白、核苷酸结合寡聚化结构域样受体蛋白3(NLRP3)炎性小体及细胞焦亡相关蛋白表达。结果:与sham组比较,CLP组小鼠24 h存活率明显降低(P<0.05);小鼠肺组织充血水肿,肺泡结构严重破坏,肺间质内大量炎症细胞浸润;肺组织W/D,细胞凋亡率,BALF中肿瘤坏死因子-α(TNF-α)、白细胞介素(IL)-6、IL-1β、IL-18水平均显著升高(P<0.05);肺组织中Casp-8 mRNA和蛋白表达水平,NLRP3、凋亡相关斑点样蛋白(ASC)、半胱氨酸天冬氨酸蛋白酶-1(Caspase-1)、切割蛋白D(GSDMD)蛋白表达水平均显著升高(P<0.05)。与CLP组比较,CLP+Z-IETD-FMK组小鼠存活率明显升高(P<0.05);小鼠肺泡结构破坏减轻,肺部炎症细胞浸润减少;肺组织W/D,细胞凋亡率,BALF中TNF-α、IL-6、IL-1β、IL-18水平均显著降低(P<0.05);肺组织中Casp-8 mRNA和蛋白表达水平,NLRP3、ASC、Caspase-1、GSDMD蛋白表达水平均显著降低(P<0.05)。结论:Casp-8通过调控NLRP3炎性小体介导的细胞焦亡减轻脓毒症引起的ALI。

南美白对虾副产物酶解工艺优化及其蛋白肽活性评价

为高质化利用南美白对虾加工副产物蛋白资源,本研究以南美白对虾加工副产物虾头虾壳为原料,蛋白水解度为考察指标,采用单因素和响应面试验优化酶解工艺。检测虾蛋白肽分子量的分布范围,评价其抗氧化能力及免疫调节作用。结果表明,碱性蛋白酶与虾头内源酶自溶酶解具有较好的协同作用,最佳酶解工艺参数值为:酶添加量4%、酶解时间6.5 h、酶解温度40℃、料液比1∶5。经蛋白层析仪检测,分子质量分布在75~1 355 Da的蛋白肽占比达到76.35%。虾蛋白肽的羟自由基清除率IC50为4.64 mg/mL、DPPH自由基清除率IC50为3.08 mg/mL,提示其具有一定的抗氧化能力。虾蛋白肽中剂量组(10 mg/kg)能显著促进淋巴细胞增殖,并提高免疫低下模型小鼠的免疫器官指数和吞噬指数,表明虾蛋白肽具有显著的免疫调节作用。

三文鱼加工副产物酶解物对肌肉的冷冻保护作用研究

目的探究三文鱼加工副产物酶解物的冷冻保护作用。方法以三文鱼头部、鱼骨以及其他副产物为原料,通过胃蛋白酶、胰蛋白酶、中性蛋白酶进行酶解制备其酶解产物,将酶解液对三文鱼进行浸渍预处理,探究3次冻融循环前后对肌肉理化性质、肌原纤维蛋白氧化和结构变化的影响,来探究三文鱼加工副产物酶解物的抗冻活性。结果三文鱼不同部位以及不同的酶所制备的酶解物在3次冻融循环后对鱼肉均表现出不同程度的抗冻活性。与对照组相比,鱼骨中性酶酶解物对鱼肉的硬度、弹性、胶着度、回复性和色泽物理性质的保护效果最明显,水分损失最少,微观程度上降低肌原纤维蛋白的冷冻氧化变性程度最大,有效维持了肌原纤维蛋白的结构稳定性。结论三文鱼鱼骨中性酶酶解物的抗冻活性最好,经过3次冻融循环后可以最大程度地减少鱼肉的冷冻变性程度,维持鱼肉的品质,这为鱼类加工副产物的有效利用以及蛋白酶解物对鱼类冷冻保护的深入研究与应用提供理论基础和实验依据。

Inducing prion protein shedding as a neuroprotective and regenerative approach in pathological conditions of the brain:from theory to facts

In the last decades,the role of the prion protein(PrP) in neurodegenerative diseases has been intensively investigated,initially in prion diseases of humans(e.g., Creutzfeldt-J akob disease) and animals(e.g.,scrapie in sheep,chronic wasting disease in deer and elk,or "mad cow disease" in cattle).Templated misfolding of physiological cellular prion protein(PrPC) into an aggregation-prone isoform(termed PrP "Scrapie"(PrPSc)),self-re plication and spreading of the latter inside the brain and to peripheral tissues,and the associated formation of infectious proteopathic seeds(termed "prions")are among the essential pathogenic mechanisms underlying this group of fatal and transmissible spongiform encephalopathies.Late r,key roles of the correctly folded PrPCwere identified in more common human brain diseases(such as Alzheimer s disease or Parkinson’s disease) associated with the misfolding and/or accumulation of other proteins(such as amyloid-β,tau or α-synuclein,respectively).PrPChas also been linked with n euro protective and regenerative functions,for instance in hypoxic/ischemic conditions such as stroke.However,despite a mixed "bouquet" of suggested functions,our understanding of pathological and,especially,physiological roles played by PrPCin the brain and beyond is ce rtainly incomplete.Interactions with various other proteins at the cell surfa ce or within intracellular compartments may account for the functional diversity linked with PrPC.Moreover,conserved endogenous proteolytic processing of PrPCgenerates seve ral defined PrPCfragments,possibly holding intrinsic functions in physiological and pathological conditions,thus making the "true and complete biology" of this protein more complicated to be elucidated.Here,we focus on one of those released PrPCfragments,namely shed PrP(sPrP),generated by a membrane-proximate ADAM10-mediated cleavage event at the cell surfa ce.Similar to other soluble PrP fragments(such as the N1 fragment representing PrP’s released N-terminal tail upon the major α-cleavage event)or expe rimentally employed recombinant PrP,sPrP is being suggested to act n euro protective in Alzheimer’s disease and other protein misfolding diseases.Seve ral lines of evidence on extracellular PrPC(fragments) suggest that induction of PrPCrelease co uld be a future therapeutic option in various brain disorders.Our recent identification of a substrate-specific approach to stimulate the shedding by ADAM 10,based on ligands binding to cell surface PrPC,may further set the stage for research into this direction.

花粉蛋白水解酶在变应性鼻炎黏膜屏障与炎症通路中的研究进展

变应性鼻炎是一种由花粉、尘螨、真菌孢子、动物皮屑等过敏原诱导的Th2炎症性疾病,发病率达32%,花粉穿透鼻黏膜屏障的机制与通路尚未完全阐明。气传花粉中蛋白水解酶是风传受精过程关键蛋白,同时参与释放花粉颗粒中的前列腺素E2(PGE2)、白三烯B4(LTB4)等炎症介质,尘螨、霉菌中蛋白水解酶可结合蛋白酶激活受体2(PAR-2)破坏细胞间紧密连接,破坏黏膜上皮屏障。真菌中的蛋白水解酶通过激活Ras/Raf1/ERK信号通路介导的Th2炎症反应。综述了花粉、尘螨、真菌中蛋白水解酶介导变应性鼻炎炎症反应的研究进展。