DNA-methylation-mediated silencing of miR-7-5p promotes gastric cancer stem cell invasion via increasing Smo and Hes1

Cancer stem cells are undifferentiated cancer cells that have self-renewal ability, a high tumorigenic activity, and a multilineage differentiation potential. MicroRNAs play a critical role in regulating gene expression during carcinogenesis. Here, we investigated the role of miR-7 and the mechanism by which it is dysregulated in gastric cancer stem cells (GCSCs). The stem cell marker, CD44, was used to sort GCSCs by fluorescence-activated cell sorting. We found that CD44 (+) cells have higher invasiveness and form more number of sphere colonies than CD44 (−) cells. Quantitative real-time polymerase chain reaction (PCR) revealed that the miR-7-5p expression was remarkably downregulated in GCSCs but was significantly increased in the methionine-deprived medium. The downregulation of miR-7-5p results from the increased DNA methylation in the promoter region using the methylation-specific PCR. Overexpression of miR-7-5p reduced the formation of colony and decreased the invasion of GCSCs through targeting Smo and Hes1 and subsequent repressing Notch and Hedgehog signaling pathways in vitro. Notably, upregulating miR-7-5p inhibited the growth of tumor in the xenograft model. Hence, these data demonstrated that miR-7-5p represses GCSC invasion through inhibition of Smo and Hes1, which provides a potential therapeutic target of gastric cancer treatment.     

Lung tissue extracellular matrix-derived hydrogels protect against radiation-induced lung injury by suppressing epithelial–mesenchymal transition

This study aimed to examine whether lung tissue extracellular matrix (ECM) hydrogels have protective effects on radiation-induced lung injury (RILI). The cytocompatibility and histocompatibility were tested for the obtained ECM-derived hydrogel. Sprague–Dawley rats were randomly divided into three groups (n = 18): control group (control); rats receiving irradiation and intratracheal injection of normal saline (IR + NS); and rats receiving irradiation and intratracheal injection of lung ECM-derived hydrogel (IR + ECM). The wet/dry weight ratio was used to evaluate the congestion and edema of the lungs. Histopathological analysis of lung tissues was performed using hemotoxylin and eosin staining and Masson's trichrome staining. Immunohistochemical staining and western blot analyses were carried out to determine the expression of epithelial–mesenchymal transition (EMT)-related proteins in lung tissues (E-cadherin, α-smooth muscle actin [α-SMA], and vimentin). In addition, tumor necrosis factor-α (TNF-α), transforming growth factor-β1 (TGF-β1) and interleukin-6 (IL-6), hydroxyproline, malondialdehyde (MDA), and superoxide dismutase (SOD) levels were also evaluated. The ECM-derived hydrogels had good cytocompatibility and histocompatibility. ECM-derived hydrogel treatment improved lung histopathology injury and pulmonary edema. Higher expression of E-cadherin and lower expression of vimentin and α-SMA were found in the IR + ECM group compared with those in the IR + NS group. Hydroxyproline levels were reduced by ECM-derived hydrogel treatment compared with those in the IR + NS group. Obvious increases of TNF-α, IL-6, and TGF-β1 were identified following irradiation. Marked reductions in MDA content and increases in SOD were induced by ECM-derived hydrogel treatment in rats after radiation. ECM-derived hydrogels were shown to protect against RILI, potentially by reducing EMT, inflammation, and oxidative damage.     

NLRC3 inhibits PDGF-induced PASMCs proliferation via PI3K-mTOR pathway

Few studies about nucleotide-oligomerization domain-like receptor subfamily C3 (NLRC3) in PASMCs have been conducted. This research aimed to investigate the role of NLRC3 on platelet-derived growth factor (PDGF)-induced proliferation of pulmonary artery smooth muscle cells (PASMCs) and its underlying mechanism. We found that the proliferation of PASMCs stimulated with PDGF decreased when phosphoinositide 3-kinase (PI3K) or mammalian target of rapamycin (mTOR) inhibitors pretreatment. Overexpression of NLRC3 inhibited the proliferation of PASMCs and the phosphorylation of PI3K and mTOR while knocking down NLRC3 reversed this effect. Targeted to PI3K or mTOR can also reverse the effect of NLRC3. Activation of PI3K increased the phosphorylation of mTOR while inhibition of PI3K reduced it. Our data suggest that PDGF can induce abnormal proliferation of PASMCs, and NLRC3 suppresses activation of the PI3K-mTOR signaling thus inhibits PASMCs proliferation. These findings unveiled the effect of NLRC3 as an inhibitor of the PI3K-mTOR pathway mediating protection against PASMCs proliferation.     

MicroRNA-29a-3p regulates abdominal aortic aneurysm development and progression via direct interaction with PTEN

Various research studies have been conducted in deducing the role of microRNAs (miRNAs) in the pathogenesis and physiological processes of various systematic diseases. This study aims at demonstration of the important role played by miR-29a-3p, through association with phosphatase and tensin homolog (PTEN), in the regulation of abdominal aortic aneurysm development and progression. Quantitative real-time polymerase chain reaction (RT-qPCR) examined miRNA-19a-3p and PMEPA1 expression in multiplied vascular smooth muscle cells (VSMCs). Cell transfection upregulated or downregulated the genes and cell counting kit-8 assay determined cellular viability. RT-qPCR detected cellular proliferation and cell death using the cell proliferation and apoptosis biomarkers Ki87 and proliferating cell nuclear antigen, caspase-8 and caspase-3, respectively. Furthermore, luciferase assay analyzed the luciferase activity and western blot analysis determined miRNA-19a-3p and PMEPA1 protein expression in proliferation and apoptosis biomarkers. TargetScan 4.2 online software ( www.targetscan.org ) was used to perform the bioinformatics analysis so as to forecast the putative targets of miR-29a-3p and PTEN. The results inferred that there was an increased expression of miRNA-29a-3p found in AAA-mimic cells with increased cellular viability and significant pathological apoptosis. Further, when the expression of miRNA-29a-3p was downregulated, it reduced the cell viability of AAA cells. On the basis of the gene interplays, it can be understood that the PTEN was directly targeted by miRNA-29a-3p so as to regulate the AAA progression. Thus, PTEN was found to strengthen the proliferation effect of miRNA-29a-3p in AAA cells. The current study thus shed more insights about the molecular mechanistic roles of miRNA-29a-3p and PTEN, opening doors for novel therapeutic approach to AAA.     

Type locality and species identity of Pareuchiloglanis sinensis (Hora & Silas) with a description of a new species of the genus from the upper Yangtze River basin in southern China

The genus Pareuchiloglanis, distributed in the Salween, Mekong, Red, Pearl and Yangtze River basins in China, Laos, Myanmar and Vietnam, consists of 20 valid species and 5 uncertain species. This study provided a taxonomic revision to Pareuchiloglanis occurring in the Yangtze River. According to the results of a morphological comparison, the type locality of Pareuchiloglanis sinensis was updated to the Nanpan-jiang (the upper Pearl River) basin; five species were identified in Pareuchiloglanis from the Yangtze River basin. Specimens formerly identified as Pareuchiloglanis sinensis from this basin were described as a new species, Pareuchiloglanis chui sp. nov. Moreover, Pareuchiloglanis tianquanensis was synonymized with Pareuchiloglanis sichuanensis. This study provided a key to these two species and three others (Pareuchiloglanis anteanalis, Pareuchiloglanis hupingshanensis and Pareuchiloglanis robusta) from the Yangtze River basin, including information about their geographical distribution. These findings provide an insight into the evolution, distribution and taxonomy of this genus for future studies.     

Dielectric Properties of Normal and Metastatic Lymph Nodes Ex Vivo From Lung Cancer Surgeries

The dielectric properties of normal and tumor human tissues have been widely reported in recent years. However, the dielectric properties of intrathoracic lymph nodes (LNs) have not been reported. In this communication, we measured the dielectric properties (i.e., permittivity and conductivity) of ex vivo intrathoracic LNs obtained from lung cancer surgeries. Results show that the permittivity and conductivity of metastatic LNs are higher than those of normal LNs over the frequency range of 1 MHz–4 GHz. Statistically significant differences are observed at single specific frequencies (64, 128, 298, 433, and 915 MHz and 2.45 GHz). Our study provides the basic data to support future-related research and fills the research gap on the dielectric properties of LNs in the lungs. Bioelectromagnetics. 2020;41:148–155. © 2020 Bioelectromagnetics Society.     

快速纯化重组腺联病毒的受体结合捕捉方法

【目的】建立用于重组腺联病毒(AAV)纯化的受体结合捕捉方法。【方法】将AAV受体的多囊肾病(PKD)结构域1和2与类弹性蛋白多肽(ELP)在重组大肠杆菌中进行融合表达,利用相变循环(ITC)纯化ELP-PKD融合蛋白;分别用昆虫和AAV-293细胞制备rAAV-GFP,与ELP-PKD融合蛋白共孵育后进行ITC,从沉淀复合物提取病毒DNA进行PCR检测;在优化条件下利用ELP-PKD蛋白结合捕捉rAAV-GFP,利用电子显微镜观察、免疫转印和细胞感染试验进行rAAV鉴定。【结果】ELP-PKD融合蛋白获得正确、可溶性表达,ITC纯化的蛋白纯度大于90%;ELP-PKD蛋白能特异结合rAAV-GFP,结合具有p H、温度和时间依赖性,受体结合捕捉方法可在1h内完成,从两种细胞纯化rAAV-GFP的回收率分别为58%和56%;rAAV-GFP洗脱具有p H和温度依赖性,洗脱rAAV-GFP的回收率分别为46%和44%;纯化rAAV-GFP具有AAV的典型形态和结构蛋白。【结论】建立的ELP-PKD结合捕捉法可用于不同细胞源rAAV的快速纯化。     

链霉菌形态分化与次级代谢产物合成的研究进展

链霉菌是一类具有复杂的形态分化周期和强大的次级代谢能力的高GC含量的放线菌,能够利用其初级代谢产生的前体化合物和能量,合成多种结构复杂、功能多样的具有生物活性的次级代谢产物,在农业、食品、畜牧业、工业以及医药研究等领域都具有重要的价值。在链霉菌的形态分化后期常常伴随着次级代谢产物的生物合成,并且两者都受到复杂的网络调控;同时链霉菌的形态对次级代谢产物的产量和种类造成很大影响。对链霉菌生长周期的全面理解将加深对链霉菌形态分化与次级代谢产物合成关系的认识。本文将对链霉菌的形态分化过程、形态分化和抗生素合成两者共同的调控因子以及链霉菌形态与抗生素产量之间的关系进行综述,这将有助于理解抗生素的合成过程,也将会在缩短发酵周期、构建高产工程菌株、新型杀菌剂的研发以及新型抗生素的合成等方面给予我们启发。     

城市绿地微生物及其对城市化的响应

城市绿地微生物的稳定性是城市绿地发挥其重要生态系统功能的重要因素。人类世时代的快速城市化会改变城市绿地土壤理化性质、输入新兴污染物、加剧微生物生态系统潜在风险、改变微生物群落多样性及生态系统功能多样性,深远地影响了城市绿地的生态系统服务功能。本文综述了城市绿地微生物的特征,以及城市化进程对城市绿地微生物组（包括土壤、植物叶际和空气）、抗生素抗性基因、病原微生物和稀有物种群落的影响。与自然微生物相比,城市绿地微生物普遍具有较高的异质性,受人类活动影响大。同时,抗生素抗性基因水平以及人类致病菌数量则显著增加,体现了城市化对城市绿地生态系统健康和功能的扰动。今后研究中应更加关注城市化对于城市绿地微生物的影响,为其对人群健康影响风险评价提供可靠理论支持。