SIK2 shRNA重组腺病毒载体构建及其在3T3-L1脂肪细胞的表达

目的构建特异性小鼠盐诱导基因（Salt induced kinase2,SIK2）的shRNA腺病毒载体,干扰脂肪细胞中SIK2的表达。方法设计3对靶向SIK2的shRNA,插入穿梭质粒pENTR/U6载体,转染3T3-L1脂肪细胞,通过Real-timePCR方法筛选最佳沉默SIK2效果的穿梭质粒,经腺病毒同源重组后,重组小鼠SIK2shRNA腺病毒载体经脂质体转染HEK293A细胞,在细胞内包装获得腺病毒颗粒AdV-SIK2-shRNA,并进行大量扩增和纯化。纯化的腺病毒感染成熟的3T3-L1脂肪细胞,通过Real-time PCR及免疫印迹法检测鼠SIK2在3T3-L1脂肪细胞中的表达水平。结果纯化后的Ad-shRNA-SIK2重组腺病毒载体可特异下调成熟3T3-L1脂肪细胞SIK2 mRNA和SIK2蛋白的表达。结论干扰3T3-L1脂肪细胞SIK2表达的短发夹RNA重组腺病毒载体构建成功。     

RNAi blocks DYT1 mutant torsinA inclusions in neurons

Early onset generalized dystonia is a dominantly inherited movement disorder caused by neuronal dysfunction without an apparent loss of neurons. The same single mutation (GAG deletion) causes most cases and results in loss of a glutamic acid (E) in the carboxy terminal region of torsinA (Delta302/303). To model the neuronal involvement, adult rat primary sensory dorsal root ganglion neurons in culture were infected with lentivirus vectors expressing human wild-type or mutant torsinA. Expression of the mutant protein resulted in formation of torsinA-positive perinuclear inclusions. When the cells were co-infected with lentivirus vectors expressing the mutant torsinA message and a shRNA selectively targeting this message, inclusion formation was blocked. Vector-delivered siRNAs have the potential to decrease the adverse effects of this mutant protein in neurons without affecting wild-type protein.     

Stable integration of a functional shRNA expression cassette into the murine leukemia virus genome

Short hairpin RNA (shRNA) can be stably expressed in cells to down-modulate gene expression. While retroviral and lentiviral vectors can be used to deliver shRNAs, the restricted viral titer is the major limitation for efficient gene transfer, which is especially important for cancer gene therapy. We were interested in using replicating murine leukemia virus (MLV) to enhance the shRNA transfer. Although stem loop structures could potentially interfere with the retroviral life cycle, we were able to demonstrate that the insertion of shRNA expression cassettes into MLV did not interfere significantly with viral fitness. The virus was genetically stable and able to silence target gene expression. Our results show that replicating MLVs are excellent tools for delivering shRNAs efficiently throughout the culture and have the potential to be used for gene function elucidation or even for cancer gene therapy.     

Examination of mesenchymal stem cell-mediated RNAi transfer to Huntington's disease affected neuronal cells for reduction of huntingtin

Huntington's disease (HD) is a fatal, autosomal dominant neurodegenerative disorder caused by an expanded trinucleotide (CAG) repeat in exon 1 of the huntingtin gene (Htt). This expansion creates a toxic polyglutamine tract in the huntingtin protein (HTT). Currently, there is no treatment for either the progression or prevention of the disease. RNA interference (RNAi) technology has shown promise in transgenic mouse models of HD by reducing expression of mutant HTT and slowing disease progression. The advancement of RNAi therapies to human clinical trials is hampered by problems delivering RNAi to affected neurons in a robust and sustainable manner. Mesenchymal stem cells (MSC) have demonstrated a strong safety profile in both completed and numerous ongoing clinical trials. MSC exhibit a number of innate therapeutic effects, such as immune system modulation, homing to injury, and cytokine release into damaged microenvironments. The ability of MSC to transfer larger molecules and even organelles suggested their potential usefulness as delivery vehicles for therapeutic RNA inhibition. In a series of model systems we have found evidence that MSC can transfer RNAi targeting both reporter genes and mutant huntingtin in neural cell lines. MSC expressing shRNA antisense to GFP were found to decrease expression of GFP in SH-SY5Y cells after co-culture when assayed by flow cytometry. Additionally MSC expressing shRNA antisense to HTT were able to decrease levels of mutant HTT expressed in both U87 and SH-SY5Y target cells when assayed by Western blot and densitometry. These results are encouraging for expanding the therapeutic abilities of both RNAi and MSC for future treatments of Huntington's disease.     

IQGAP1 involvement in MTOC and granule polarization in NK-cell cytotoxicity

Natural killer (NK) cells form a region of tight contact called the NK immunological synapse (NKIS) with their target cells. This is a dynamic region serving as a platform for targeted signaling and exocytotic events. We previously identified IQGAP1 as a cytoskeletal component of the NK-like cell line YTS. The present study was undertaken to determine the role of IQGAP1 in the function of NK cells. Silencing of IQGAP1 expression resulted in almost complete loss of the cytotoxic activity of YTS cells. Loss of IQGAP1 did not prevent conjugate formation with target cells but it did result in a failure to reorient the microtubule organizing centre to the immune synapse. Significantly, IQGAP1 expression was required for the perigranular accumulation of an F-actin network. IQGAP1 was shown to undergo marked rearrangements during synapse maturation in effector target conjugates of YTS or primary NK cells. These results suggest previously undescribed role(s) for IQGAP1 in regulating multiple aspects of cytoskeletal organization and granule polarization in NK cells.     

乙酰肝素酶shRNA双基因共表达真核载体的构建和筛选

目的：构建并筛选有效的、编码2条shRNA的乙酰肝素酶（Hpa）特异性基因真核表达载体．方法：分别设计、化学合成6对寡核苷酸单链,经退火、连接和磷酸化后得到Hpa shRNA双链,将两两随机问隔4～8个碱基后定向克隆入带有各自的U6启动子和终止码、共同的绿色荧光蛋白（green fluoreseent protein,EGFP）基因和Neo基因的pGenesil-1中,构建3条含两段Hpa基因shRNA的pGenesil-1-Hpa—shRNA真核表达载体,转染卵巢癌细胞株SKOV3,流式细胞仪和荧光显微镜下观察转染效率,免疫组化分析Hpa蛋白表达．结果：酶切与测序证实pGenesil-1-HPSE—shRNA构建成功,无任何碱基突变,3组质粒转染细胞均有Hpa表达的变化,3种不同shRNA质粒转染细胞后Hpa蛋白表达有明显差别．结论：构建并筛选了针对Hpa特异性的双基因shRNA真核表达载体pGenesil-1-Hpa-shRNA．     

siRNA和shRNA在syt基因沉默中的一致性

目的通过小干扰RNA(small interference RNA,siRNA)和短发夹RNA(short hairpin RNA,shRNA)对PC12细胞中Synaptotagmin(syt)基因表达沉默效果的比较,确认siRNA在基因沉默中与shRNA的等效性.方法用T7 RNA聚合酶体外合成的针对syt Ⅰ与Ⅸ的siRNA和在H1.1载体上构建的shRNA表达质粒转染PC12细胞,用标记荧光蛋白和免疫荧光检测shRNA和siRNA的转染率,用Western印迹方法检测沉默效果.结果siRNA和shRNA在PC12细胞中沉默syt Ⅰ和Ⅸ的表达时,有一致的沉默效率.结论siRNA可作为基因沉默中快速筛选的工具,可在RNA干扰的应用中与shRNA 配合使用.     

RNAi screening reveals a synthetic chemical–genetic interaction between ATP synthase and PFK1 in cancer cells

To meet cellular bioenergetic and biosynthetic demands, cancer cells remodel their metabolism to increase glycolytic flux, a phenomenon known as the Warburg effect and believed to contribute to cancer malignancy. Among glycolytic enzymes, phosphofructokinase-1 (PFK1) has been shown to act as a rate-limiting enzyme and to facilitate the Warburg effect in cancer cells. In this study, however, we found that decreased PFK1 activity did not affect cell survival or proliferation in cancer cells. This raised a question regarding the importance of PFK1 in malignancy. To gain insights into the role of PFK1 in cancer metabolism and the possibility of adopting it as a novel anticancer therapeutic target, we screened for genes that caused lethality when they were knocked down in the presence of tryptolinamide (TLAM), a PFK1 inhibitor. The screen revealed a synthetic chemical–genetic interaction between genes encoding subunits of ATP synthase (complex V) and TLAM. Indeed, after TLAM treatment, the sensitivity of HeLa cells to oligomycin A (OMA), an ATP synthase inhibitor, was 13,000 times higher than that of untreated cells. Furthermore, this sensitivity potentiation by TLAM treatment was recapitulated by genetic mutations of PFK1. By contrast, TLAM did not potentiate the sensitivity of normal fibroblast cell lines to OMA, possibly due to their reduced energy demands compared to cancer cells. We also showed that the PFK1-mediated glycolytic pathway can act as an energy reservoir. Selective potentiation of the efficacy of ATP synthase inhibitors by PFK1 inhibition may serve as a foundation for novel anticancer therapeutic strategies.     

Apelin triggers macrophage polarization to M2 type in head and neck cancer

Cancer comes after cardiovascular diseases in terms of mortality rate in the world. Chemotherapy, radiotherapy and surgical interventions are the current cancer treatment. Recently, it has been observed that immunotherapeutic approaches provide a significant improvement when used along with these interventions. The mononuclear system mainly consists of macrophages that play an active role in the pathology of many diseases because of having high plasticity capacities. Previous research suggested that they can be used as an alternative to cancer treatment. Aim was to investigate the effect of apelin on macrophage polarization in the tumor microenvironment.Mouse macrophage cell line RAW264.7 cells and head and were chosen for this study. The apelin expression was knockdown in neck cell carcinoma cell line SCCL MT1 cells using shRNA technique. SCCL MT1 cells having normal or suppressed apelin expression were co-cultured with mouse macrophage RAW264.7 cells. The effect of co-culturing on the expression of inflammatory genes in RAW264.7 cells was investigated.Suppressed apelin expression in SCCL MT1 cells resulted in elevated pro-inflammatory response in co-cultured macrophages. Expression of the IL1β, IL6, and TNFα genes significantly increased, however anti-inflammatory cytokine levels were significantly decreased. However, in the control group, a downregulation was determined in pro-inflammatory genes, while an increase was observed in anti-inflammatory genes. The protein levels of these cytokines in concordance with the RT-PCR analysis.As a result of this study, apelin released from cancer cells was found to affect macrophage polarization. These results indicated that the apelin peptide may cause the intense presence of M2-type macrophages in the tumor niche, and the therapeutic approaches targeting of apelin in cancer cells may have a potential role in macrophage polarization.