小鼠FGFR3可控性RNAi载体的构建和抑制效率验证

目的构建小鼠成纤维细胞生长因子受体3(fibroblast growth factor receptor 3,FGFR3)可控性RNAi载体及RNAi载体,并在体外验证后者效率。方法以含有pLoxPneo基因的pBSK/U6载体为骨架,首先构建针对FGFR3的可控性RNAi载体pBSU6/FGFR3i,然后经Cre重组酶去除neo基因后得到RNAi载体FGFR3-RNAi。将FGFR3-RNAi与FGFR3表达载体分别共转染RAW264.7和HEK293T细胞株,经半定量RT-PCR和Western blot分别检测FGFR3 mRNA和蛋白表达情况。结果成功构建针对FGFR3的可控性敲低载体和RNAi载体;FGFR3载体在细胞水平可明显降低FGFR3 mRNA的丰度及蛋白表达。结论为进一步获得FGFR3可控性敲低的小鼠模型奠定基础。

RNAi Mediated Silencing of Gene Encoding 1-Deoxy-D-Xylulose-5-Phosphate Reductoisomerase (DXR) in <i>Centella asiatica</i>

Centella asiatica (L.) is one of the most valuable medicinal plants since prehistoric times. The pharmaceutical importance of this herb is due to the accumulation of large quantities of pentacyclic triterpenoid saponins, collectively known as centelloids synthesized by the isoprenoid biosynthesis pathway. Biosynthesis of triterpenoid in the plants proceeds via either of the two pathways, viz. Mevalonate (MVA) pathway (in the cytosol) or 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway (in plastid). In Centella, the pathway leading to the accumulation of triterpenoid is still not known or elucidated. Thus, to know whether the MVA or MEP pathway or a cross-talk between the pathway leads to the biosynthesis of triterpenoid, silencing the key regulatory gene using RNAi tool, of each of the pathway and then analyze a metabolite is an efficient approach. The key regulatory enzyme of the MVA pathway i.e. 3-Hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) has already been successfully silenced using RNAi tool [1]. In the present study, the 1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXR) a key regulatory enzyme in MEP pathway is silenced. The RNAi-DXR construct in pHANNIBAL vector was cloned into a binary vector pART27 and subsequently transformed into Agrobacterium strain AGL1. The transient analysis of the RNAi-CaDXR using semi-quantitative RT-PCR confirmed the silencing of the endogenous DXR gene in Nicotiana and further confirmed in Centella asiatica. The present study is the first step aimed to delineate the MEP pathway using RNAi silencing approach to elucidate its role in the accumulation of triterpenoid in this important medicinal plant.

骨形成蛋白4条件性RNA干扰小鼠的建立

为研究骨形成蛋白4(Bone morphogenetic protein 4,BMP4)在骨骼发育中的作用,我们以含有LoxPneo的pBSK/U6载体为骨架,构建小鼠BMP4条件性RNAi(conditional RNA interference),CRNA;载体(BMP4CRNAi),经KpnⅠ和AflⅢ双酶切获取针对bmp4并含neo基因的目的干扰片段,纯化后的目的片段显微注射入0.5d的FVB/NJ小鼠受精卵,并植入同期发情的假孕母鼠中,获取G0代转基因小鼠;利用PCR对G0代转基因小鼠基因型进行鉴定,PCR阳性的小鼠与FVB/NJ小鼠交配,最终获取稳定传代的BMP4CRNAi小鼠。稳定传代的BMP4CRNAi小鼠与成骨和软骨前体细胞表达Cre的转基因小鼠(Col2a1-Cre)交配,获取BMP4Col2a1-CRNAi小鼠。分离BMP4Col2a1-CRNAi小鼠原代软骨细胞,提取总RNA,利用半定量RT-PCR检测RNA干扰效率。小鼠基因型鉴定结果表明:成功获得条件性RNAi转基因小鼠;BMP4干扰效率检测结果表明:在软骨细胞中BMP4的干扰效率为81%。以上结果表明,我们成功制备了BMP4CRNAi小鼠和BMP4Col2a1-CRNAi小鼠,BMP4CRNAi小鼠与不同Cre转基因小鼠交配,可以研究BMP4在不同细胞、组织和器官的功能,BMP4Col2a1-CRNAi小鼠的获得为研究BMP4在软骨发育中的作用提供了合适的动物模型。

Inhibition of Rgs10 Expression Prevents Immune Cell Infiltration in Bacteria-induced Inflammatory Lesions and Osteoclast-mediated Bone Destruction

Regulator of G-protein Signaling 10 （Rgsl0） plays an important function in osteoclast differentiation. However, the role of Rgsl0 in immune cells and inflammatory responses, which activate osteoclasts in inflam- matory lesions, such as bacteria-induced periodontal disease lesions, remains largely unknown. In this study, we used an adeno-associated virus （AAV-） mediated RNAi （AAV-shRNA-Rgs10） knockdown approach to study Rgsl0＇s function in immune cells and osteoclasts in bacteria-induced inflammatory lesions in a mouse model of periodontal disease. We found that AAV-shRNA-Rgs10 mediated Rgs10 knockdown impaired osteoclastogenesis and osteoclast-mediated bone resorption, in vitro and in vivo. Interestingly, local injection of AAV-shRNA-Rgs10 into the periodontal tissues in the bacteria-induced inflammatory lesion greatly decreased the number of dendritic cells, T-cells and osteoclasts, and protected the periodontal tissues from local inflammatory damage and bone destruction. Importantly, AAV-mediated Rgs10 knockdown also reduced local expression of osteoclast markers and pro-inflammatory cytokines. Our results demonstrate that AAV- shRNA-Rgs10 knockdown in periodontal disease tissues can prevent bone resorption and inflammation simultaneously. Our data indicate that Rgsl0 may regulate dendritic cell proliferation and maturation, as well as the subsequent stimulation of T-cell proliferation and maturation, and osteoclast differentiation and acti- vation. Our study suggests that AAV-shRNA-Rgs10 can be useful as a therapeutic treatment of periodontal disease.

A molecular, phylogenetic and functional study of the <i>dADAR</i>mRNA truncated isoform during <i>Drosophila</i>embryonic development reveals an editing-independent function

Adenosine Deaminases Acting on RNA (ADARs) have been studied in many animal phyla, where they have been shown to deaminate specific adenosines into inosines in duplex mRNA regions. In Drosophila, two isoform classes are encoded, designated full-length (contains the editase domain) and truncated (lacks this domain). Much is known about the full-length isoform, which plays a major role in regulating functions of voltage-gated ion channel proteins in the adult brain. In contrast, almost nothing is known about the functional significance of the truncated isoform. In situ hybridization shows that both isoform mRNA classes are maternally derived and transcripts for both localize primarily to the developing central nervous system. Quantitative RT-PCR shows that about 35% of all dADAR mRNA transcripts belong to the truncated class in embryos. 3’-RACE results show that abundance of the truncated isoform class is developmentally regulated, with a longer transcript appearing after the mid-blastula transition.3’-UTR sequences for the truncated isoform have been determined from diverse Drosophila species and important regulatory regions including stop codons have been mapped. Western analysis shows that both mRNA isoform classes are translated into protein during embryonic development, as full-length variant levels gradually diminish. The truncated protein isoform is present in every Drosophila species studied, extending over a period spanning about 40 x 106 years, implying a conserved function. Previous work has shown that a dADAR protein isoform binds to the evolutionarily conserved rnp-4f pre-mRNA stem-loop located in the 5’-UTR to regulate splicing, while no RNA editing was observed, suggesting the hypothesis that it is the non-catalytic truncated isoform which regulates splicing. To test this hypothesis, we have utilized RNAi technology, the results of which support the hypothesis. These results demonstrate a novel, non-catalytic function for the truncated dADAR protein isoform in Drosophila embryonic development, which is very likely evolutionarily conserved.

Application of RNA interference in triatomine （Hemiptera： Reduviidae） studies

Triatomines （Hemiptera： Reduviidae） are obligate hematophagous insects. They are of medical importance because they are vectors of Trypanosoma cruzi, the causative agent of Chagas disease in the Americas. In recent years, the RNA interference （RNAi） technology has emerged as a practical and useful alternative means of studying gene function in insects, including triatomine bugs. RNAi research in triatomines is still in its early stages, several issues still need to be elucidated, including the description of the molecules involved in the RNAi machinery and aspects related to phenotype evaluation and persistence of the knockdown in different tissues and organs. This review considers recent applications of RNAi to triatomine research, describing the major methods that have been applied during the knockdown process such as the double-stranded RNA delivery mechanism （injection, microinjection, or ingestion） and the phenotype characterization （mRNA and target protein levels） in studies conducted with the intent to provide greater insights into the biology of these insects. In addition to the characterization of insect biomolecules, some with biopharmacological potential, RNAi may provide a new view of the interaction between triatomine and trypanosomatids, enabling the development of new measures for vector control and transmission of the parasite.