新早期胃癌标志物PRDX4通过清除ROS促进胃癌的发生发展

胃癌是全球第四大最常见的癌症,也是全球癌症中引起死亡的第二大原因。为了降低胃癌的死亡率,目前亟需解决的问题是发现新的早期胃癌特异性的标志物,提高早期胃癌的检出率,从而从根本上解决胃癌死亡率高的问题。实验室前期研究发现过氧化物酶4 (Peroxiredoxin 4,PRDX4)具有早期胃癌标志物的潜能,文中通过建立恶性转化模型及转化细胞过表达等方法,研究PRDX4在转化细胞中的作用。结果显示PRDX4通过减少转化细胞中活性氧(Reactive oxygen species,ROS)含量,使细胞处在利于生长增殖的微环境中,从而促进细胞发生恶性转化,即PRDX4通过清除ROS促进胃癌的发生发展。     

Human iPSC‐derived neural precursor cells differentiate into multiple cell types to delay disease progression following transplantation into YAC128 Huntington's disease mouse model

ObjectivesTo investigate whether human HLA‐homozygous induced pluripotent stem cell (iPSC)‐derived neural precursor cells (iPSC‐NPCs) can provide functional benefits in Huntington’s disease (HD), we transplanted them into the YAC128 transgenic HD mouse model.Materials and MethodsCHAi001‐A, an HLA‐homozygous iPSC line (A*33:03‐B*44:03‐DRB1*13:02), was differentiated into neural precursor cells, and then, they were transplanted into 6 months‐old YAC128 mice. Various behavioural and histological analyses were performed for five months after transplantation.ResultsMotor and cognitive functions were significantly improved in transplanted animals. Cells transplanted in the striatum showed multipotential differentiation. Five months after transplantation, the donor cells had differentiated into neurons, oligodendrocytes and astrocytes. Transplantation restored DARPP‐32 expression, synaptophysin density, myelin basic protein expression in the corpus callosum and astrocyte function.ConclusionAltogether, these results strongly suggest that iPSC‐NPCs transplantation induces neuroprotection and functional recovery in a mouse model of HD and should be taken forward for clinical trials in HD patients.     

Long non-coding RNA-ATB promotes EMT during silica-induced pulmonary fibrosis by competitively binding miR-200c

Long non-coding RNAs (lncRNAs) are important signal transduction regulators that act by various patterns. However, little is known about the molecular mechanisms of lncRNA related pathways in occupational lung fibrosis. Our previous study found that epithelial-mesenchymal transition (EMT) was one of the key events in silica-induced pulmonary fibrosis. This study showed that the lncRNA-ATB promoted EMT by acting as a miR-200c sponge. miR-200c was identified by miRNA array as a potential target of lncRNA-ATB and verified by dual luciferase reporter gene together with RNA pull-down assays. Moreover, our findings demonstrated that lncRNA-ATB is abundantly expressed during EMT of lung epithelial cells, which contributes to decreased levels of miR-200c. miR-200c targeted ZEB1 to relief silicosis by blocking EMT in vivo and in vitro. The results also suggested M2 macrophages secreted transforming growth factor-β1 (TGF-β1) to induce EMT process by activating lncRNA-ATB in epithelial cells. Collectively, silica-stimulated macrophages secreted TGF-β1 to induce lncRNA-ATB in epithelia cells, promoting EMT by binding with miR-200c and releasing ZEB1. These observations provide further understanding of the regulatory network of silica-induced pulmonary fibrosis and identify new therapeutic targets hopefully.     

Metagenomic sequencing reveals viral abundance and diversity in mosquitoes from the Shaanxi-Gansu-Ningxia region,China

BackgroundMosquitoes host and transmit numerous arthropod-borne viruses (arboviruses) that cause disease in both humans and animals. Effective surveillance of virome profiles in mosquitoes is vital to the prevention and control of mosquito-borne diseases in northwestern China, where epidemics occur frequently.MethodsMosquitoes were collected in the Shaanxi-Gansu-Ningxia region (Shaanxi Province, Gansu Province, and Ningxia Hui Autonomous Region) of China from June to August 2019. Morphological methods were used for taxonomic identification of mosquito species. High-throughput sequencing and metagenomic analysis were used to characterize mosquito viromes.ResultsA total of 22,959 mosquitoes were collected, including Culex pipiens (45.7%), Culex tritaeniorhynchus (40.6%), Anopheles sinensis (8.4%), Aedes (5.2%), and Armigeres subalbatus (0.1%). In total, 3,014,183 (0.95% of clean reads) viral sequences were identified and assigned to 116 viral species (including pathogens such as Japanese encephalitis virus and Getah virus) in 31 viral families, including Flaviviridae, Togaviridae, Phasmaviridae, Phenuiviridae, and some unclassified viruses. Mosquitoes collected in July (86 species in 26 families) showed greater viral diversity than those from June and August. Culex pipiens (69 species in 25 families) and Culex tritaeniorhynchus (73 species in 24 families) carried more viral species than Anopheles sinensis (50 species in 19 families) or Aedes (38 species in 20 families) mosquitoes.ConclusionViral diversity and abundance were affected by mosquito species and collection time. The present study elucidates the virome compositions of various mosquito species in northwestern China, improving the understanding of virus transmission dynamics for comparison with those of disease outbreaks.     

A proteomic approach for identifying cellular proteins interacting with erythropoietin in recombinant Chinese hamster ovary cells

Identification of the cellular proteins interacting with incompletely folded and unfolded forms of erythropoietin (EPO) in recombinant CHO (rCHO) cells leads to better insight into the possible genetic manipulation approaches for increasing EPO production. To do so, a pull‐down assay was performed with dual‐tagged (N‐terminal GST‐ and C‐terminal hexahistidine‐tagged) EPO expressed in E. coli as bait proteins and cell lysates of rCHO cells (DG44) as prey proteins. Cellular proteins interacting with dual‐tagged EPO were then resolved by two‐dimensional gel electrophoresis (2DE) and identified by MALDI‐TOF MS/MS. A total of 27 protein spots including glucose‐regulated protein 78 (GRP78) were successfully identified. Western blot analysis of GRP78 confirmed the results of the MS analyses. Taken together, a pull‐down assay followed by a proteomic approach is found to be an efficient means to identify cellular proteins interacting with foreign protein in rCHO cells. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010     

SILAC analysis of oxidative stress‐mediated proteins in human pneumocytes: New role for treacle

To better understand lung oxidant stress responses, we examined A549 lung cells exposed to H₂O₂ using “stable isotope labeling by amino acids.” We identified 466 cytosolic and 387 nuclear proteins; H₂O₂ exposure produced ≥twofold differences in 31, all were downregulations. None were previously reported as oxidant stress response proteins, although they share common functions. One of the responders, treacle, was linked to p53, an important oxidative stress response. The Treacher Collins–Franceschetti syndrome can result from treacle mutation and insufficiency was suggested to cause increased p53 leading to the syndrome. However, results here indicate p53 and treacle responses to H₂O₂ are independent: treacle remains suppressed after p53 recovery; the threshold for treacle reduction is well above that for p53 induction; and treacle suppression by short interfering RNA does not modify the p53 response. Evidence of treacle antioxidant activity include reduction being driven by proteasome degradation independently of mRNA, typical for oxidant‐absorbing proteins, and increased sensitivity to H₂O₂ consequent to short interfering RNA suppression. Data here show a link between oxidative stress and treacle reduction, demonstrate that treacle does not control p53, provide evidence of a treacle oxidant defense role, support the hypothesis that oxidant stress plays a role in the Treacher Collins–Franceschetti syndrome, and raise the possibility that treacle plays an anti‐oxidant role in lungs.     

53BP1 promotes ATM activity through direct interactions with the MRN complex

The Mre11/Rad50/Nbs1 (MRN) complex has a central function in facilitating activation of the ATM protein kinase at sites of DNA double‐strand breaks (DSBs). However, several other factors are also required in human cells for efficient signalling through MRN and ATM, including the tumour suppressor proteins p53‐binding protein 1 (53BP1) and BRCA1. In this study, we investigate the functions of these mediator proteins in ATM activation and find that the presence of 53BP1 and BRCA1 can amplify the effects of MRN when interactions between MRN and ATM are compromised. This effect is dependent on a direct interaction between MRN and the tandem breast cancer carboxy‐terminal (BRCT) repeats in 53BP1, and is accompanied by hyper‐phosphorylation of both Nbs1 and 53BP1. We also find that the BRCT domains of 53BP1 affect the overall structure of 53BP1 multimers and that this structure is important for promoting ATM phosphorylation of substrates as well as for the repair of DNA DSBs in mammalian cells.     

Involvement of c‐Jun N‐terminal kinase and extracellular signal‐regulated kinase 1/2 in EGF‐induced angiogenesis

Angiogenesis is a process during which endothelial cells divide and migrate to form new capillaries from the preexisting blood vessels. The present study was designed to investigate whether MAPKs (mitogen‐activated protein kinases) play crucial roles in regulating EGF (epidermal growth factor)‐induced endothelial cell angiogenesis. Our results showed that EGF stimulated HUVEC (human umbilical vein endothelial cells) proliferation in a concentration‐dependent manner, of which the maximum effective concentration of EGF was 10 ng/ml. Western blot analysis showed that EGF at 10 ng/ml significantly induced the phosphorylation of ERK1/2 (extracellular signal‐regulated kinase 1 and 2) and p38 kinase at 5 min, while it induced the phosphorylation of JNK/SAPK (c‐Jun N‐terminal kinase/stress‐activated protein kinase) at 15 min. Further results showed that a JNK/SAPK inhibitor, SP600125, and a specific siRNA JNK/SAPK could both significantly inhibit EGF‐induced tube formation in HUVEC cells, and an ERK1/2 inhibitor PD098059 could also block the tube formation in some content, while a p38 inhibitor SB203580 failed to do so. Furthermore, only SP600125 significantly inhibited EGF‐induced HUVEC cell proliferation under no cytotoxic concentration, so did JNK/SAPK siRNA. In conclusion, JNK/SAPK and ERK1/2 signals therefore play critical roles in EGF‐mediated HUVEC cell angiogenesis.