Xenophagy in Helicobacter pylori‐ and Epstein–Barr virus‐induced gastric cancer

Helicobacter pylori and Epstein–Barr virus (EBV) account for roughly 80% and 10%, respectively, of gastric carcinomas worldwide. Autophagy is an evolutionarily conserved and intricately regulated cellular process that involves the sequestration of cytoplasmic proteins and organelles into double‐membrane autophagosomes that eventually fuse with lysosomes for degradation of the engulfed content. Emerging evidence indicates that xenophagy, a form of selective autophagy, plays a crucial role in the pathogenesis of H. pylori‐ and EBV‐induced gastric cancer. Xenophagy specifically recognizes intracellular H. pylori and EBV and physically targets these pathogens to the autophagosomal–lysosomal pathway for degradation. In this connection, H. pylori or EBV‐induced dysregulation of autophagy may be causally linked to gastric tumourigenesis and therefore can be exploited as therapeutic targets. This review will discuss how H. pylori and EBV infection activate autophagy and how these pathogens evade recognition and degradation by the autophagic pathway. Elucidating the molecular aspects of H. pylori‐ and EBV‐induced autophagy will help us better understand the pathogenesis of gastric cancer and promote the development of autophagy modulators as antimicrobial agents. Published by John Wiley & Sons, Ltd     

Autophagy mediates neutrophil responses to bacterial infection

Neutrophils constitute the first line of cellular defense against pathogens and autophagy is a fundamental cellular homeostasis pathway that operates with the intracellular degradation/recycling system. Induction of the autophagic process in neutrophils, in response to invading pathogens, constitutes a crucial mechanism in innate immunity. Exploration of autophagy has greatly progressed and diverse strategies have been reported for studying this molecular process in different biological systems; especially in infectious and inflammatory diseases. Furthermore, the role of autophagy in neutrophils, during pathogenic infection, continues to be of interest, due to the role of the cell in immunity function, its recruitment to the site of infection and its implication in inflammatory diseases. This review focuses on the known role of autophagy in neutrophils defence against pathogenic infections. A more detailed discussion will concern the recent findings highlighting the role of autophagy in inflammation and cell death in infected neutrophils.     

Autophagy Activity in Pulmonary Metastatic Tumor Tissues from Colorectal Cancer: A Pilot Study

Purpose

Autophagy has been reported to be involved in treatment failure in tumor. We aimed to evaluate autophagy activity in tumor tissue and compare them between the recurrence and non-recurrence groups.

Materials and Methods

We analyzed expressions of autophagy-related proteins in tumor tissues which were obtained from pulmonary metastases of colorectal cancer patients by Western blot. We also analyzed autophagosomes by transmission electron microscopy.

Results

Tumor tissues from recurrence group showed increased levels of LC3B-II, decreased levels of p62/SQSTM1, and also a marked accumulation of autophagosomes compared with tissues from non-recurrence group.

Conclusion

The present study suggests that autophagy may be associated with treatment failure of metastatic colorectal cancer.     

柯萨奇病毒B组3型2B蛋白诱导细胞自噬及其基序鉴定

目的 探讨柯萨奇病毒B组3型(CVB3) woodruff病毒2B蛋白对细胞自噬的诱导作用,及其自噬相关基序的鉴定.方法 分别构建增强型绿色荧光蛋白(EGFP)与CVB3 woodruff病毒2B蛋白及其9种截短蛋白的融合蛋白(EGFP-2B、EGFP-2B1-249、EGFP-2B1-201、EGFP-2B1-153、EGFP-2B1-105、EGFP-2B1-57、EGFP-2B106.201、EGFP-2B106-249、EGFP-2 B205-297、EGFP-2B106-201)真核表达载体,红色荧光蛋白(mCherry)与微管相关蛋白轻链3(LC3)的融合蛋白真核表达载体pmCherry-LC3;应用激光共聚焦与蛋白质免疫印迹(Western blot)检测病毒2B蛋白对宫颈癌细胞(HeLa) LC3表达的影响;荧光显微镜观察9种截短蛋白在HeLa细胞中的表达;Western blot检测pEGFP-2B和pEGFP-2B106-249转染细胞后LC3的表达;观察自噬抑制剂3-甲基腺苷(3-MA)处理后,pEGFP-2B和pEGFP-2B106-249诱导细胞自噬的情况.结果 CVB3攻击HeLa细胞后,mCherry-LC3呈现细胞核周点状聚集表达,Western blot检测出现清晰LC3-Ⅱ条带;pEGFP-2B与pmCherry-LC3共转染后也可见细胞核周围绿色荧光与红色荧光均成点状聚集并相互重叠,且LC3-Ⅱ条带明显;9种截短融合蛋白质粒分别转染HeLa细胞后,其中可见细胞核周围绿色荧光点状聚集的最短截短蛋白为EGFP-2B106-249;pEGFP-2B和pEGFP-2B106-249转染细胞后可检测出现清晰LC3-Ⅱ条带;3-MA处理后,pEGFP-2B和pEGFP-2B106-249分别与pmCherry-LC3共转染的细胞均未见绿色和红色荧光的核周点状聚集.结论 CVB3 woodruff病毒2B蛋白可以诱导宿主细胞发生自噬,其中截短蛋白2B106-249是病毒蛋白2B诱导HeLa细胞发生自噬的功能基序.     

Cell death mechanisms induced by synergistic effects of halofuginone and artemisinin in colorectal cancer cells

Our previous study found that the combination of halofuginone (HF) and artemisinin (ATS) synergistically arrest colorectal cancer (CRC) cells at the G1/G0 phase of the cell cycle; however, it remains unclear whether HF-ATS induces cell death. Here we report that HF-ATS synergistically induced caspase-dependent apoptosis in CRC cells. Specifically, both in vitro and in vivo experiments showed that HF or HF-ATS induces apoptosis via activation of caspase-9 and caspase-8 while only caspase-9 is involved in ATS-induced apoptosis. Furthermore, we found HF or HF-ATS induces autophagy; ATS can''t induce autophagy until caspase-9 is blocked. Further analyzing the crosstalk between autophagic and caspase activation in CRC cells, we found autophagy is essential for activation of caspase-8, and ATS switches to activate capase-8 via induction of autophagy when caspase-9 is inhibited. When apoptosis is totally blocked, HF-ATS switches to induce autophagic cell death. This scenario was then confirmed in studies of chemoresistance CRC cells with defective apoptosis. Our results indicate that HF-ATS induces cell death via interaction between apoptosis and autophagy in CRC cells. These results highlight the value of continued investigation into the potential use of this combination in cancer therapy.     

人黄韧带细胞骨化发生过程中的自噬

文题释义： 黄韧带骨化症：是由于脊柱黄韧带发生骨向分化而形成的一种韧带骨化疾病,常导致椎管狭窄,造成脊髓受压,并产生不可逆损害,出现肢体感觉障碍,严重的将导致瘫痪。目前对黄韧带骨化病因学研究取得了一定的进展,但其具体的发病机制仍未完全明确。 自噬：因外界或自身环境的改变,细胞器和胞内蛋白通过溶酶体进行分解消化并重新利用,从而达到适应外界环境、维持细胞内环境稳定的过程,是真核细胞特有一种表现形式。 MAPK信号通路：是生物体内重要的信号转导系统之一,它可以被物理应激、炎性细胞因子、生长因子以及细胞复合物等一系列细胞外信号或刺激激活,从而参与介导细胞生长、发育、分裂以及分化等多种生理及病理过程。在哺乳动物细胞中MAPK信号通路的主要信号分子包括ERK1/2、JNK以及P38等。 背景：黄韧带骨化发生的病理机制尚不清楚,临床上无有效的药物或非手术治疗的方法。目前研究发现,骨桥蛋白与自噬在成骨过程中均发挥重要作用,二者在黄韧带骨化中的作用尚不清楚。 目的：通过对骨桥蛋白和自噬在黄韧带骨化发生机制的研究,尝试找出药物治疗的潜在作用靶点。 方法：①黄韧带骨化病、胸椎骨折或单纯腰椎间盘突出症患者行后路全椎板切除减压获取黄韧带,将标本分为骨化组和非骨化组,每组各取8例标本,通过免疫组化染色观察骨桥蛋白、骨钙素及自噬指标Beclin-1、LC3、P62的表达;②通过组织块贴壁法进行黄韧带细胞的分离培养,并用不同质量浓度的骨桥蛋白干预不同时间来构建体外黄韧带细胞骨化模型;③非骨化组黄韧带细胞用不同浓度的自噬抑制剂3-甲基腺嘌呤干预后,再用100 μg/L骨桥蛋白诱导,应用Western blot检测骨化指标碱性磷酸酶、骨钙素的表达变化;④用100 μg/L骨桥蛋白干预非骨化黄韧带细胞,并在0,15,30,60,120 min终止骨化诱导过程,应用Western blot检测MAPK信号通路中重要分子ERK1/2、JNK、P38的磷酸化情况;⑤非骨化组黄韧带细胞用ERK1/2特异的磷酸化阻滞剂U0126阻断ERK1/2通路磷酸化后,再用100 μg/L骨桥蛋白诱导,应用Western blot检测碱性磷酸酶以及骨钙素的表达变化。 结果与结论：①骨化黄韧带和非骨化黄韧带组织骨钙素、骨桥蛋白的免疫组化均呈阳性表达;骨化黄韧带组织中Beclin-1呈阳性表达,而LC3及P62未见明显阳性结果;非黄韧带骨化组织中Beclin-1、LC3、P62均呈阳性表达;②与非骨化组比较,骨化组黄韧带细胞中碱性磷酸酶和骨钙素的表达增加;骨桥蛋白可诱导黄韧带骨化,骨桥蛋白的作用具有浓度相关性和时间相关性;③自噬强弱与骨化程度呈负相关,即自噬越明显,骨化作用越弱;④骨桥蛋白能使MAPK信号通路磷酸化,并具有一定的时间相关性;抑制MAPK磷酸化过程后,骨桥蛋白仍然能够诱导黄韧带细胞的骨化;⑤结果表明,黄韧带骨化发生过程中,信号通路上ERK1/2、骨桥蛋白、骨钙素、碱性磷酸酶分子的上下游关系为：ERK1/2→骨桥蛋白→骨钙素/碱性磷酸酶。 ORCID: 0000-0003-0008-9802(许国峰) 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

炎症性肠病的自噬与表观遗传修饰

文题释义：自噬：是一个吞噬自身细胞质蛋白或细胞器并使其包被进入囊泡,并与溶酶体融合形成自噬溶酶体,降解其所包裹的内容物的过程,以此实现细胞本身的代谢需要和某些细胞器的更新。 表观遗传：是指DNA序列不发生变化,但基因表达却发生了可遗传的改变,主要包括DNA甲基化、组蛋白修饰、染色质重塑以及非编码RNA的调控,这种改变在细胞发育和增殖过程中能稳定的传递。 背景：炎症性肠病是一种与肠道自身免疫相关的慢性炎症性疾病,自噬是促进免疫调节的细胞途径,相关基因的表达异常与肠道炎症以及免疫反应关系密切,而表观遗传修饰对炎症性肠病自噬的调控机制尚未阐明。 目的：文章旨在对表观遗传修饰在炎症性肠病自噬中的调控作用作一介绍,以期探讨炎症性肠病自噬的发生机制。 方法：检索PubMed数据库,检索时限1998年1月至2019年4月,检索关键词为“inflammatory bowel disease,autophagy,autophagy related genes,epigenetic modification,DNA methylation,histone modification,chromatin remodeling,miRNA”,选择61篇符合标准的文献。 结果与结论：表观遗传(DNA甲基化、组蛋白修饰、染色质重塑、非编码RNA)可通过修饰炎症性肠病的易感基因ATG、IRGM等来调控肠道炎症、免疫以及自噬,从而介导炎症性肠病的发生和发展。 ORCID: 0000-0003-0627-9236(郭娅静) 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

黄芩苷调控自噬保护肠黏膜屏障干预肠道急性移植物抗宿主病

文题释义：移植物抗宿主病：是由于移植后异体供者移植物中的T淋巴细胞,经受者发动的一系列“细胞因子风暴”刺激,显著增强了其对受者抗原的免疫反应,以受者靶细胞为目标发动细胞毒攻击,其中皮肤、肝及肠道是主要的靶目标。根据移植物抗宿主病在移植后发生的时间,如在100 d内发生者称为急性移植物抗宿主病,在100 d后发生者称为慢性移植物抗宿主病。黄芩苷：黄芩汤的君药黄芩,《神农本草经》谓可治“肠辟泄利”,性苦寒,可清肺胃胆及大肠经之湿热,黄芩苷是黄芩中提取的一种黄酮类化合物,具有抑菌、清除氧自由基等作用,减轻蛋白酶与炎性因子对组织的损害。 摘要背景：急性移植物抗宿主病是造血干细胞移植后早期最容易致死的并发症之一,如何干预急性移植物抗宿主病病程是个热点问题。目的：探讨黄芩苷调控自噬干预肠道急性移植物抗宿主病的机制。方法：⁶⁰Co照射CB6F1小鼠4 h,立即尾静脉输注Balb/c小鼠单个核细胞悬液(骨髓+脾),建立单倍体造血干细胞移植模型。造模后当天开始模型组灌胃生理盐水,治疗组灌胃黄芩苷,剂量为30 mg/(kg·d),共14 d。治疗后进行小鼠急性移植物抗宿主病临床评分、小肠黏膜急性移植物抗宿主病病理评级,透射电镜观察小肠黏膜自噬泡结构,流式细胞仪检测小肠黏膜上皮细胞活性氧水平,Western blot检测自噬相关蛋白LC3Ⅱ、LC3-Ⅰ、Beclin1的表达。结果与结论：①治疗组临床急性移植物抗宿主病评分、小肠黏膜病理评级明显优于模型组;②透射电镜下模型组存在自噬泡但线粒体结构毁坏严重,治疗组自噬泡增多且线粒体结构相对完整;③治疗组小鼠小肠黏膜上皮细胞活性氧水平低于模型组(P < 0.01),治疗组LC3Ⅱ/Ⅰ、Beclin1的表达水平明显高于模型组(P < 0.01);④结果表明,黄芩苷可以通过降低活性氧的产生,提高小肠黏膜细胞的自噬水平,保护肠黏膜屏障,进而降低移植后肠道急性移植物抗宿主病的发病率。ORCID: 0000-0002-8771-5898(崔兴) 中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程