Claudin蛋白家族在泌尿系肿瘤中的研究进展北大核心

Claudin蛋白家族是构成细胞紧密连接(tight junctions,TJs)的重要骨架蛋白,在细胞极性、上皮屏障特性、细胞运动性和细胞间的稳定性等方面发挥着关键作用。最近研究发现,Claudin蛋白家族在人类多种肿瘤中都有表达失调,起着癌基因或者抑癌基因的作用。本文综述了近年来Claudin蛋白家族在泌尿系统肿瘤(膀胱癌、前列腺癌、肾癌)中的研究进展。     

紧密连接蛋白Claudin-3与三阴性乳腺癌患者临床特征的相关性

目的:探讨紧密连接蛋白Claudin-3与三阴性乳腺癌患者临床特征的相关性。方法:自2012年3月至2017年3月，收集我院收治的三阴性乳腺癌患者108例，行乳腺癌根治术，术中取乳腺癌标本和癌旁标本，检测组织中紧密连接蛋白Claudin-3表达情况，分析紧密连接蛋白Claudin-3与患者临床病理参数的相关性。对患者随访1年，分析术后1年复发患者与不复发患者组织中紧密连接蛋白Claudin-3的差异。结果:乳腺癌组织和癌旁组织中紧密连接蛋白Claudin-3表达无统计学差异(P=0.331)。与紧密连接蛋白Claudin-3阴性的患者相比，紧密连接蛋白Claudin-3阳性的患者TNM分期为Ⅲ期的比例显著增高(52.46% vs 29.79%,P=0.018),淋巴结转移比例增高(55.74% vs 29.79%,P=0.007),术后复发率显著增高(26.23% vs 10.64%,P=0.042)。结论:紧密连接蛋白Claudin-3与淋巴结转移和TNM分期有关，对预测患者术后复发具有一定价值。     

养血解毒方对银屑病角质形成细胞紧密连接的调节作用

目的:观察银屑病样小鼠皮损紧密连接蛋白中水闸蛋白(claduin-1,claudin-7),闭锁蛋白(occludin)的表达,明确养血解毒方对银屑病表皮通透屏障的修复作用,为养血解毒方治疗银屑病提供科学依据。方法:将C57BL/6J小鼠随机分为空白组、模型组、甲氨喋呤组、养血解毒方组,制备甲氨喋呤溶液、养血解毒方水煎剂对应灌胃干预,同时小鼠背部剃毛后给予咪喹莫特涂抹诱导银屑病样皮损模型。每日拍照记录皮损形态并对严重程度指数(PASI)评分;水油测试笔检测皮损表皮含水量;苏木素-伊红(HE)染色观察其病理改变、测量表皮厚度;免疫荧光法检测增殖相关的核抗原(Ki67);免疫组化法检测表皮兜甲蛋白(loricrin),真皮中CD3^+T淋巴细胞浸润和紧密连接蛋白claduin-1,claudin-7,occludin的表达;蛋白免疫印迹法(Western blot)检测皮损中claudin-7,occludin的表达。模拟银屑病皮损微环境,建立白细胞介素-17(IL-17,1 mg·L^-1)刺激的角质形成细胞(Hacat)模型,制作养血组分、解毒组分、养血解毒方喷干粉进行干预。采用细胞增殖毒性检测试剂盒-8(CCK-8)法检测药物对Hacat细胞的毒性;细胞免疫荧光法检测药物对角质形成细胞claudin-1,claudin-7,occludin表达的干预作用。结果:与模型组比较,养血解毒方可显著减轻小鼠银屑病样皮损表现,降低PASI评分及皮损表皮厚度(P<0.01),增加皮损区表皮水分含量(P<0.01),减少表皮ki67,loricrin的异常表达和真皮CD3+T细胞浸润(P<0.01),并增加紧密连接蛋白claudin-1,claudin-7,occludin的表达(P<0.05),增加紧密连接结构的完整性;体外研究发现,与模型组比较,养血解毒方组和养血组分组明显升高紧密连接蛋白claudin-1,claudin-7,occludin的表达(P<0.05);与模型组比较,解毒组分组蛋白表达水平无统计学差异。结论:养血解毒方通过调节角质形成细胞间紧密连接的表达抑制其异常的增殖分化过程,进一步恢复破坏的表皮通透屏障,可能是其治疗银屑病的作用机制之一。其中养血解毒方的养血组分对调节紧密连接的修复起主要作用。     

GDF15 promotes simultaneous astrocyte remodeling and tight junction strengthening at the blood–brain barrier

Perivascular astrocyte processes (PAP) surround cerebral endothelial cells (ECs) and modulate the strengthening of tight junctions to influence blood–brain barrier (BBB) permeability. Morphologically altered astrocytes may affect barrier properties and trigger the onset of brain pathologies. However, astrocyte-dependent mediators of these events remain poorly studied. Here, we show a pharmacologically driven elevated expression and release of growth/differentiation factor 15 (GDF15) in rat primary astrocytes and cerebral PAP. GDF15 has been shown to possess trophic properties for motor neurons, prompting us to hypothesize similar effects on astrocytes. Indeed, its increased expression and release occurred simultaneously to morphological changes of astrocytes in vitro and PAP, suggesting modulatory effects of GDF15 on these cells, but also neighboring EC. Administration of recombinant GDF15 was sufficient to promote astrocyte remodeling and enhance barrier properties between ECs in vitro, whereas its pharmacogenetic abrogation prevented these effects. We validated our findings in male high anxiety-related behavior rats, an animal model of depressive-like behavior, with shrunk PAP associated with reduced expression of the junctional protein claudin-5, which were both restored by a pharmacologically induced increase in GDF15 expression. Thus, we identified GDF15 as an astrocyte-derived trigger of astrocyte process remodeling linked to enhanced tight junction strengthening at the BBB.     

Bioinformatic identification of key candidate genes and pathways in axon regeneration after spinal cord injury in zebrafish

Zebrafish and human genomes are highly homologous;however,despite this genomic similarity,adult zebrafish can achieve neuronal proliferation,regeneration and functional restoration within 6–8 weeks after spinal cord injury,whereas humans cannot.To analyze differentially expressed zebrafish genes between axon-regenerated neurons and axon-non-regenerated neurons after spinal cord injury,and to explore the key genes and pathways of axonal regeneration after spinal cord injury,microarray GSE56842 was analyzed using the online tool,GEO2R,in the Gene Expression Omnibus database.Gene ontology and protein-protein interaction networks were used to analyze the identified differentially expressed genes.Finally,we screened for genes and pathways that may play a role in spinal cord injury repair in zebrafish and mammals.A total of 636 differentially expressed genes were obtained,including 255 up-regulated and 381 down-regulated differentially expressed genes in axon-regenerated neurons.Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment results were also obtained.A protein-protein interaction network contained 480 node genes and 1976 node connections.We also obtained the 10 hub genes with the highest correlation and the two modules with the highest score.The results showed that spectrin may promote axonal regeneration after spinal cord injury in zebrafish.Transforming growth factor beta signaling may inhibit repair after spinal cord injury in zebrafish.Focal adhesion or tight junctions may play an important role in the migration and proliferation of some cells,such as Schwann cells or neural progenitor cells,after spinal cord injury in zebrafish.Bioinformatic analysis identified key candidate genes and pathways in axonal regeneration after spinal cord injury in zebrafish,providing targets for treatment of spinal cord injury in mammals.     

Epithelial physical barrier defects in chronic rhinosinusitis

Introduction: Chronic rhinosinusitis (CRS) is a common upper airway disease with a prevalence of greater than 10% of the general population. Although the pathogenesis of CRS remains poorly understood, there is growing evidence indicating that epithelial physical barrier defects play an important role in CRS pathogenesis.

Areas covered: Epithelial physical barriers are maintained by various intercellular junctions, especially tight junctions (TJs). Recent studies suggest that the expression of TJ molecules and epithelial barrier function in human nasal epithelium are modulated by various internal and external factors. This review summarizes recent advances regarding the structure, function, and regulating mechanisms of the epithelial physical barrier in the context of CRS.

Expert opinion: Available data indicate that epithelial physical barrier defects in CRS can result from inhaled allergens, microbial or virus infections, cytokines, hypoxia, or zinc deficiency, among other causes. Several genes/molecules, such as SPINK5, S100A7, S100A8/9, PCDH1, NDRG1, SPRR, and p63 are involved in modulating the physical barrier function in the context of CRS. The exact mechanisms and molecular pathways that lead to these barrier defects, however, require additional study. Additional work is necessary to further explore the epithelial physical barrier function in normal and pathologic sinonasal mucosa.     

Virulence factors impair epithelial junctions during bacterial infection

Epithelial cells are typically connected through different types of cell junctions that are localized from the apical membrane to the basal surface. In this way, epithelium cells form the first barrier against pathogenic microorganisms and prevent their entry into internal organs and the circulatory system. Recent studies demonstrate that bacterial pathogens disrupt epithelial cell junctions through targeting junctional proteins by secreted virulence factors. In this review, we discuss the diverse strategies used by common bacterial pathogens, including Pseudomonas aeruginosa, Helicobacter pylori, and enteropathogenic Escherichia coli, to disrupt epithelial cell junctions during infection. We also discuss the potential of targeting the pathogenic mechanisms in the treatment of pathogen‐associated diseases.     

Nasal epithelial barrier disruption by particulate matter ≤2.5 μm via tight junction protein degradation

Upper airway diseases including sinonasal disorders may be caused by exposure to fine particulate matter (≤2.5 μm; PM2.5), as proven by epidemiological studies. PM2.5 is a complex entity whose chemical constituents and physicochemical properties are not confined to a single, independent “particle” but which in this study means a distinctive environmental “toxin.” The mechanism whereby PM2.5 induces nasal epithelial barrier dysfunction leading to sinonasal pathology remains unknown. In the present study, human nasal epithelial cells were exposed to non‐cytotoxic doses of PM2.5 to examine how PM2.5 affects the nasal epithelial barrier. Tight junction (TJ) integrity and function were assessed by transepithelial electric resistance and paracellular permeability. The expression levels of TJ proteins such as zona occludens‐1, occludin and claudin‐1 were assessed by immunofluorescence staining and western blot. PM2.5 exposure induced epithelial barrier dysfunction as reflected by increased paracellular permeability and decreased transepithelial electric resistance. TJ proteins zona occludens‐1, occludin and claudin‐1 were found to be downregulated. Pretreatment with N‐acetyl‐l ‐cysteine alleviated PM2.5‐mediated reactive oxygen species generation in RPMI 2650 cells, further preventing barrier dysfunction and attenuating the degradation of TJ proteins. These results suggest that PM2.5 induces nasal epithelial barrier disruption via oxidative stress, and N‐acetyl‐l ‐cysteine counteracts this PM2.5‐mediated effect. Thus, nasal epithelial barrier disruption caused by PM2.5, which leads to sinonasal disease, may be prevented or treated through the inhibition of reactive oxygen species.     

山姜素对葡聚糖硫酸钠诱导小鼠溃疡性结肠炎的保护作用及其作用机制研究

目的探讨山姜素对葡聚糖硫酸钠诱导的溃疡性结肠炎小鼠的保护作用及其作用机制。方法 C57BL/6小鼠随机分为对照组、模型组和25、50、100 mg/kg山姜素组。模型组和治疗组每天给予3%葡聚糖硫酸钠溶液,连续7 d。治疗组每日ip生理盐水0.5 m L+25、50、100 mg/kg山姜素,对照组和模型组每天ip生理盐水0.5 m L,连续7 d。观察小鼠体质量变化、结肠长度、疾病活动指数(DAI)评分、组织学损伤评分等炎症反应;透射电镜观察肠上皮细胞间连接;免疫组织化学法、Western blotting法检测肠道紧密连接蛋白claudin-2、occludin、ZO-1、STAT3、p STAT3、IL-6的表达和STAT3/IL-6信号通路的表达情况。结果与模型组比较,山姜素能够显著缓解小鼠体质量减轻和肠管缩短,降低DAI和组织学评分。山姜素可增强小鼠肠黏膜occludin、ZO-1表达,减弱claudin-2表达,并能够抑制STAT3/IL-6信号通路。结论山姜素能够上调葡聚糖硫酸钠诱导的溃疡性结肠炎小鼠结肠组织occludin、ZO-1的表达,下调claudin-2的表达,通过调节紧密连接蛋白的表达,保护肠上皮细胞屏障的完整性和通透性。通过抑制IL-6/STAT3通路,减轻结肠炎症反应。