LncRNA SNHG12 promotes tumorigenesis and metastasis in osteosarcoma by upregulating Notch2 by sponging miR-195-5p

Osteosarcoma is the most common primary malignant bone tumor and has a high fatality rate in children and adolescents. Recently, an increasing amount of evidence has demonstrated that lncRNAs have crucial roles in regulating biological characteristics in malignant tumors. Therefore, this research was carried out to uncover the biological function and the potential molecular mechanism of SNHG12 in osteosarcoma. In this study, we found that SNHG12 was significantly upregulated in both osteosarcoma tissues and cell lines and osteosarcoma patients with high levels of SNHG12 tended to have a poor prognosis. We evaluated the biological function of SNHG12 in 143B and U2OS cells and show that the downregulation of SNHG12 suppressed cell proliferation by blocking cell cycle progression at the G0/G1 phase and weakened cell invasion and migration abilities. Dual-luciferase reporter and RIP assays were conducted to confirm that SNHG12 functioned as a ceRNA, modulating the expression of Notch2 by sponging miR-195-5p in osteosarcoma. We further demonstrate that Notch2 played a crucial role in activating the Notch signaling pathway. In conclusion, SNHG12 might serve as a valuable biomarker and prognosis factor in osteosarcoma patients. The SNHG12/miR-195-5p/Notch2-Notch signaling pathway axis might become a novel therapeutic for osteosarcoma.     

Hemopexin increases the neurotoxicity of hemoglobin when haptoglobin is absent

Hemopexin (Hpx) binds heme with extraordinary affinity, and after haptoglobin may provide a second line of defense against the toxicity of extracellular hemoglobin (Hb). In this series of experiments, the hypothesis that Hpx protects neurons from Hb neurotoxicity was evaluated in murine primary cultures containing neurons and glial cells. Contrary to hypothesis, Hpx increased neuronal loss due to micromolar concentrations of Hb by 4‐ to 12‐fold, as measured by LDH release assay; conversely, the neurotoxicity of hemin was completely prevented. The endogenous fluorescence of Hpx was quenched by Hb, consistent with transfer of Hb‐bound heme to Hpx. This was associated with precipitation of globin chains, as detected by immunostaining and fluorescent Hb labeling. A portion of this precipitate attached firmly to cells and could not be removed by multiple washes. Concomitant treatment with haptoglobin (Hp) prevented globin precipitation and most of the increase in neuronal loss. Hpx weakly attenuated the increase in culture non‐heme iron produced by Hb treatment, quantified by ferrozine assay. However, Hb‐Hpx toxicity was iron‐dependent, and was blocked by deferoxamine and ferrostatin‐1. Up‐regulation of cell ferritin expression, a primary cell defense against Hb toxicity, was not observed on western blots of culture lysates that had been concomitantly treated with Hpx. These results suggest that Hpx destabilizes Hb in the absence of haptoglobin, leading to globin precipitation and exacerbation of iron‐dependent oxidative cell injury. Combined therapy with hemopexin plus haptoglobin may be preferable to hemopexin alone after CNS hemorrhage.

     

重组人心房利钠肽 (ANP) 的原核表达、纯化及鉴定

为提高重组人心房利钠肽(Atrial natriuretic peptide,ANP)的表达量,将3个ANP通过赖氨酸(Lysine,K)串联,并构建相对应的重组表达载体p ET28a(+)/ANP3。转染大肠杆菌进行诱导表达,目的蛋白约占菌体总蛋白的60%。经过包涵体变复性,赖氨酸酶(Lys-C)和羧肽酶(CPB)水解,以及一系列层析纯化,每升培养液可获得约16 mg的ANP蛋白。最终,纯化后的ANP经UPLC及Tricine SDS-PAGE鉴定,纯度大于90%,LC-MS鉴定显示其分子量为3 080 Da,且为二硫键正确形成的ANP单体,通过ELISA试剂盒检测,其具有和参比品一致活性。本研究为ANP的大规模制备打下了基础。同时,所采用的串联表达技术也为其他多肽类药物的重组表达提供了新的思路。     

转录激活因子样效应物核酸酶介导的山羊β-乳球蛋白基因敲除和人乳铁蛋白基因定点整合

为了敲除山羊乳中致敏源β-乳球蛋白(BLG)基因,同时在BLG基因座定点整合人乳铁蛋白(hLF)基因。首先针对山羊BLG第3外显子识别位点设计了1对特异性TALEN-3-L/R质粒对;同时,构建了含有1个HSV-TK负筛选基因的hLF基因打靶载体BLC14-TK。TALENs质粒对转染山羊胎儿成纤维细胞,2μg/m L嘌呤霉素筛选3 d,PCR扩增产物测序来验证其切割DNA活性。打靶载体BLC14-TK与TALEN-3-L/R质粒对共转染山羊胎儿成纤维细胞,经700μg/m L G418和2μg/m L GCV共筛选药物抗性细胞株;通过整合检测和同源重组检测来筛选hLF基因打靶细胞株;BLG~–/hLF~+打靶细胞株作为供核细胞进行山羊体细胞核移植。结果为:TALEN-3-L/R致突变率为25%-30%;获得BLG~–/hLF~+打靶细胞6株;共制作重构胚胎335枚,移植受体山羊23只,B超检测到30-35 d的妊娠受体9只(妊娠率39.1%),其中1只50日龄克隆胎儿验证为BLG~–/hLF~+基因型。以上结果表明获得BLG基因座定点整合hLF基因的基因打靶山羊是可行的,为培育羊乳中含低致敏原和富含hLF的山羊新品系奠定了基础。     

A short motif in Arabidopsis CDK inhibitor ICK1 decreases the protein level,probably through a ubiquitin‐independent mechanism

The ICK/KRP family of cyclin‐dependent kinase (CDK) inhibitors modulates the activity of plant CDKs through protein binding. Previous work has shown that changing the levels of ICK/KRP proteins by overexpression or downregulation affects cell proliferation and plant growth, and also that the ubiquitin proteasome system is involved in degradation of ICK/KRPs. We show in this study that the region encompassing amino acids 21 to 40 is critical for ICK1 levels in both Arabidopsis and yeast. To determine how degradation of ICK1 is controlled, we analyzed the accumulation of hemagglutinin (HA) epitope‐tagged ICK1 proteins in yeast mutants defective for two ubiquitin E3 ligases. The highest level of HA‐ICK1 protein was observed when both the N‐terminal 1–40 sequence was removed and the SCF (SKP1–Cullin1–F‐box complex) function disrupted, suggesting the involvement of both SCF‐dependent and SCF‐independent mechanisms in the degradation of ICK1 in yeast. A short motif consisting of residues 21–30 is sufficient to render green fluorescent protein (GFP) unstable in plants and had a similar effect in plants regardless of whether it was fused to the N‐terminus or C‐terminus of GFP. Furthermore, results from a yeast ubiquitin receptor mutant rpn10Δ indicate that protein ubiquitination is not critical in the degradation of GFP‐ICK1^1–40 in yeast. These results thus identify a protein‐destabilizing sequence motif that does not contain a typical ubiquitination residue, suggesting that it probably functions through an SCF‐independent mechanism.     

Induction of multiple cytotoxic T lymphocyte responses in mice by a multiepitope DNA vaccine against dengue virus serotype 1

Dengue virus (DENV) is still a major threat to human health in most tropical and subtropical countries and regions. In the present study, a multi‐epitope DNA vaccine that encodes 15 immunogenic and conserved HLA‐A*0201‐, HLA‐A*1101‐, HLA‐A*2402‐restricted CTL epitopes from DENV serotype 1 (DENV‐1) was constructed based on the eukaryotic expressing plasmid pcDNA^TM3.1/myc‐His(?) A. Immunization of HLA‐A*0201, HLA‐A*1101 and HLA‐A*2402 transgenic mice with the recombinant plasmid pcDNA^TM3.1/myc‐His(?) A‐DENV‐1‐Meg resulted in significantly greater IFN‐γ‐secreting T‐cell responses against most (14/15) CTL epitopes than occurred in mice immunized with the empty plasmid pcDNA^TM3.1/myc‐His(?) A. Additionally, the epitope‐specific T cells directed to some epitopes secreted not only IFN‐γ but also IL‐6 and/or TNF‐α. Finally, the induced epitope‐specific T cells also efficiently lysed epitope‐pulsed splenocytes and DENV‐1‐infected splenic monocytes. The present study confirms the immunogenicity of multi‐epitope DENV vaccine, suggesting that it may contribute to the development of a universal DENV vaccine.

     

Orthosteric,Allosteric and Biased Signalling at the Relaxin-3 Receptor RXFP3

Relaxin-3 is a neuropeptide that has roles in stress, memory and appetite regulation. The peptide acts on its cognate receptor RXFP3 to induce coupling to inhibitory G proteins to inhibit adenylyl cyclase and activate MAP-kinases such as ERK1/2, p38MAPK and JNK. Other relaxin family peptides can activate the receptor to produce alternative patterns of signalling and there is an allosteric modulator 135PAM1 that displays probe-selectivity. There are now a variety of selective peptide agonists and antagonists that will assist in the determination of the physiological roles of the relaxin-RXFP3 system and its potential as a drug target.     

Comparative proteomic analysis reveals the positive effect of exogenous spermidine on photosynthesis and salinity tolerance in cucumber seedlings

Key message

Our results based on proteomics data and physiological alterations proposed the putative mechanism of exogenous Spd enhanced salinity tolerance in cucumber seedlings.

Abstract

Current studies showed that exogenous spermidine (Spd) could alleviate harmful effects of salinity. It is important to increase our understanding of the beneficial physiological responses of exogenous Spd treatment, and to determine the molecular responses underlying these responses. Here, we combined a physiological analysis with iTRAQ-based comparative proteomics of cucumber (Cucumis sativus L.) leaves, treated with 0.1 mM exogenous Spd, 75 mM NaCl and/or exogenous Spd. A total of 221 differentially expressed proteins were found and involved in 30 metabolic pathways, such as photosynthesis, carbohydrate metabolism, amino acid metabolism, stress response, signal transduction and antioxidant. Based on functional classification of the differentially expressed proteins and the physiological responses, we found cucumber seedlings treated with Spd under salt stress had higher photosynthesis efficiency, upregulated tetrapyrrole synthesis, stronger ROS scavenging ability and more protein biosynthesis activity than NaCl treatment, suggesting that these pathways may promote salt tolerance under high salinity. This study provided insights into how exogenous Spd protects photosynthesis and enhances salt tolerance in cucumber seedlings.